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Yokoo T, Tanabe A, Yoshida Y, Caaveiro JMM, Nakakido M, Ikeda Y, Fujimura Y, Matsumoto M, Entzminger K, Maruyama T, Okumura CJ, Nangaku M, Tsumoto K. Antibody recognition of complement Factor H reveals a flexible loop involved in Atypical Hemolytic Uremic Syndrome pathogenesis. J Biol Chem 2022; 298:101962. [PMID: 35452676 PMCID: PMC9127587 DOI: 10.1016/j.jbc.2022.101962] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 04/15/2022] [Accepted: 04/16/2022] [Indexed: 11/28/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a disease associated with dysregulation of the immune complement system, especially of the alternative pathway (AP). Complement factor H (CFH), consisting of 20 domains called CCP1-20, downregulates the AP as a cofactor for mediating C3 inactivation by complement factor I (CFI). However, anomalies related to CFH are known to cause excessive complement activation and cytotoxicity. In aHUS, mutations and the presence of anti-CFH autoantibodies (AAbs) have been reported as plausible causes of CFH dysfunction, and it is known that CFH-related aHUS carries a high probability of end-stage renal disease. Elucidating the detailed functions of CFH at the molecular level will help to understand aHUS pathogenesis. Herein, we used biophysical data to reveal that a heavy-chain antibody fragment, termed VHH4, recognized CFH with high affinity. Hemolytic assays also indicated that VHH4 disrupted the protective function of CFH on sheep erythrocytes. Furthermore, X-ray crystallography revealed that VHH4 recognized the Leu1181-Leu1189CCP20 loop, a known anti-CFH AAbs epitope. We next analyzed the dynamics of the C-terminal region of CFH, and showed that the epitopes recognized by anti-CFH AAbs and VHH4 were the most flexible regions in CCP18-20. Finally, we conducted mutation analyses to elucidate the mechanism of VHH4 recognition of CFH, and revealed that VHH4 inserts Trp1183CCP20 residue of CFH into the pocket formed by the complementary determining region 3 loop. These results suggested that anti-CFH AAbs may adopt a similar molecular mechanism to recognize the flexible loop of Leu1181-Leu1189CCP20, leading to aHUS pathogenesis.
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Affiliation(s)
- Takanori Yokoo
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Aki Tanabe
- Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Yoko Yoshida
- Division of Nephrology and Endocrinology, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Jose M M Caaveiro
- Department of Global Healthcare, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Makoto Nakakido
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
| | - Yoichiro Ikeda
- Division of Nephrology and Endocrinology, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Yoshihiro Fujimura
- Department of Blood Transfusion Medicine, Nara Medical University, 840, Shijo-Cho, Kashihara, Nara, 634-8521, Japan
| | - Masanori Matsumoto
- Department of Blood Transfusion Medicine, Nara Medical University, 840, Shijo-Cho, Kashihara, Nara, 634-8521, Japan
| | - Kevin Entzminger
- Abwiz Bio Inc, 9823 Pacific Heights Blvd, Ste J, San Diego, California, 92121, USA
| | - Toshiaki Maruyama
- Abwiz Bio Inc, 9823 Pacific Heights Blvd, Ste J, San Diego, California, 92121, USA
| | - C J Okumura
- Abwiz Bio Inc, 9823 Pacific Heights Blvd, Ste J, San Diego, California, 92121, USA
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Kouhei Tsumoto
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan; The institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan.
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Guan S, Jian L, He Y, Su Y, Zhou L. Bioinformatic identification of differentially expressed genes regulated by DNA-methylation in glioblastoma. Eur J Neurosci 2021; 55:1278-1290. [PMID: 34963193 DOI: 10.1111/ejn.15580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 11/25/2022]
Abstract
DNA methylation-driven differentially expressed genes (DEGs) play potentially important roles in glioblastoma (GBM). In the present study, we applied bioinformatic analyses to identify key methylation-regulated DEGs (MeDEGs) in glioblastoma and elucidate their functions. Gene expression and methylation profile data from glioblastoma samples along with clinical information were obtained from GEO and TCGA databases. A total of 65 genes were identified as MeDEGs from the aforementioned data. Subsequently, gene ontology and kyoto encyclopedia of genes and genomes enrichment analyses of these MeDEGs exhibited that MeDEGs were mostly enriched in several tumor-related terms such as "activation of cysteine-type endopeptidase activity involved in apoptotic process" and "phospholipid scrambling". Kaplan-Meier survival analysis demonstrated significant correlation of CASP1, CFH, and TTLL7 hyper-methylation with patient prognosis. Finally, CASP1 protein could indirectly interact with CFH protein, but interaction of TTLL7 protein with CASP1 or CFH protein was not evident. Based on gene set enrichment analysis, hyper-methylation of CASP1, CFH, and TTLL7 were found enriched in tumor-related KEGG terms, such as "RNA degradation", "apyruvate metabolism", and "nitrogen metabolism". Methylation levels of CASP1, CFH, and TTLL7 were addressed to negatively correlate with their mRNA levels in GBM cell lines. In sum, the present identification of MeDEGs associated with overall survival put forth potential molecular targets for translation towards improved diagnosis and treatment of GBM and specifically, methylation levels of CASP1, CFH, and TTLL7 genes could serve as key prognostic biomarkers in GBM.
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Affiliation(s)
- Sizhong Guan
- Department of Neurosurgery, The First Hospital of China Medical University, Shenyang, P.R. China
| | - Linge Jian
- West China Medical School, Sichuan University, Chengdu, P.R. China
| | - Ye He
- Department of Laboratory, The First Hospital of China Medical University, Shenyang, P.R. China
| | - Yanna Su
- Department of Laboratory, The First Hospital of China Medical University, Shenyang, P.R. China
| | - Liping Zhou
- Post Graduation Training Department, The First Hospital of China Medical University, Shenyang, P.R. China
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3
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Haydock L, Garneau AP, Tremblay L, Yen HY, Gao H, Harrisson R, Isenring P. Genetic abnormalities in biopsy-proven, adult-onset hemolytic uremic syndrome and C3 glomerulopathy. J Mol Med (Berl) 2021; 100:269-284. [PMID: 34714369 PMCID: PMC8770394 DOI: 10.1007/s00109-021-02102-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 06/03/2021] [Accepted: 06/08/2021] [Indexed: 12/25/2022]
Abstract
Abstract Atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G) have been linked to mutations in many of the proteins that are involved in alternative complement pathway activation. Age and etiology confounded, the prevalence of such mutations has been reported to be over 30 to 50% in these diseases. However, the cohorts studied included many children or individuals with a familial history of complement-related disorders and genetic tests were usually limited to exome sequencing of known causative or risk-associated genes. In this study, a retrospective adult cohort of 35 patients with biopsy-proven thrombotic microangiopathy (the largest in Canada) and 10 patients with C3 glomerulopathy was tested through an extended exome panel to identify causative defects in associated or candidate genes including those of the alternative and terminal complement pathways. A variant of unknown significance was also analyzed for pathogenicity through in vitro studies. To our surprise, the prevalence of known causative or risk-associated variants in either of these cohorts was found to be less than ~ 15% overall. However, the panel used and analyses carried out allowed to identify novel variants of potential clinical significance and a number of candidate genes. The prevalence of known genetic defects in adult-onset aHUS and C3G is thus probably much lower than 30 to 50%. Our results also point towards the importance of investigating diseases of the alternative complement pathway through extended exome panels and in vitro analyses. Key messages The alternative complement pathway plays a major role in the pathogenesis of hemolytic uremic syndrome and C3 glomerulopathy. Based on previous studies, both disorders have been commonly linked to variants in the various intermediates that sustain or regulate this pathway. The prevalence of such mutations in the adult-onset and sporadic forms of these diseases is probably much lower than expected based on larger series. The sporadic forms of complementopathies are likely to involve additional genes that are yet to be uncovered.
Supplementary information The online version contains supplementary material available at 10.1007/s00109-021-02102-1.
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Affiliation(s)
- Ludwig Haydock
- Nephrology Research Group, L'Hôtel-Dieu de Québec Research Center, Department of Medicine, Faculty of Medicine, Laval University, Quebec, QC, G1R2J6, Canada
| | - Alexandre P Garneau
- Nephrology Research Group, L'Hôtel-Dieu de Québec Research Center, Department of Medicine, Faculty of Medicine, Laval University, Quebec, QC, G1R2J6, Canada.,Cardiometabolic Axis, School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montréal, 900, rue Saint-Denis, Montreal, QC, H2X 0A9, Canada
| | - Laurence Tremblay
- Nephrology Research Group, L'Hôtel-Dieu de Québec Research Center, Department of Medicine, Faculty of Medicine, Laval University, Quebec, QC, G1R2J6, Canada
| | - Hai-Yun Yen
- Fulgent Genetics, Temple City, CA, 91780, USA
| | - Hanlin Gao
- Fulgent Genetics, Temple City, CA, 91780, USA
| | - Raphaël Harrisson
- Nephrology Research Group, L'Hôtel-Dieu de Québec Research Center, Department of Medicine, Faculty of Medicine, Laval University, Quebec, QC, G1R2J6, Canada
| | - Paul Isenring
- Nephrology Research Group, L'Hôtel-Dieu de Québec Research Center, Department of Medicine, Faculty of Medicine, Laval University, Quebec, QC, G1R2J6, Canada.
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4
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Complement Inhibitors in Age-Related Macular Degeneration: A Potential Therapeutic Option. J Immunol Res 2021; 2021:9945725. [PMID: 34368372 PMCID: PMC8346298 DOI: 10.1155/2021/9945725] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 07/07/2021] [Accepted: 07/14/2021] [Indexed: 11/18/2022] Open
Abstract
Age-related macular degeneration (AMD) is a multifactorial disease, which can culminate in irreversible vision loss and blindness in elderly. Nowadays, there is a big gap between dry AMD and wet AMD on treatment. Accounting for nearly 90% of AMD, dry AMD still lacks effective treatment. Numerous genetic and molecular researches have confirmed the significant role of the complement system in the pathogenesis of AMD, leading to a deeper exploration of complement inhibitors in the treatment of AMD. To date, at least 14 different complement inhibitors have been or are being explored in AMD in almost 40 clinical trials. While most complement inhibitors fail to treat AMD successfully, two of them are effective in inhibiting the rate of GA progression in phase II clinical trials, and both of them successfully entered phase III trials. Furthermore, recently emerging complement gene therapy and combination therapy also offer new opportunities to treat AMD in the future. In this review, we aim to introduce genetic and molecular associations between the complement system and AMD, provide the updated progress in complement inhibitors in AMD on clinical trials, and discuss the challenges and prospects of complement therapeutic strategies in AMD.
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Pollack S, Eisenstein I, Mory A, Paperna T, Ofir A, Baris-Feldman H, Weiss K, Veszeli N, Csuka D, Shemer R, Glaser F, Prohászka Z, Magen D. A Novel Homozygous In-Frame Deletion in Complement Factor 3 Underlies Early-Onset Autosomal Recessive Atypical Hemolytic Uremic Syndrome - Case Report. Front Immunol 2021; 12:608604. [PMID: 34248927 PMCID: PMC8264753 DOI: 10.3389/fimmu.2021.608604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/24/2021] [Indexed: 11/21/2022] Open
Abstract
Background and Objectives Atypical hemolytic uremic syndrome (aHUS) is mostly attributed to dysregulation of the alternative complement pathway (ACP) secondary to disease-causing variants in complement components or regulatory proteins. Hereditary aHUS due to C3 disruption is rare, usually caused by heterozygous activating mutations in the C3 gene, and transmitted as autosomal dominant traits. We studied the molecular basis of early-onset aHUS, associated with an unusual finding of a novel homozygous activating deletion in C3. Design, Setting, Participants, & Measurements A male neonate with eculizumab-responsive fulminant aHUS and C3 hypocomplementemia, and six of his healthy close relatives were investigated. Genetic analysis on genomic DNA was performed by exome sequencing of the patient, followed by targeted Sanger sequencing for variant detection in his close relatives. Complement components analysis using specific immunoassays was performed on frozen plasma samples from the patient and mother. Results Exome sequencing revealed a novel homozygous variant in exon 26 of C3 (c.3322_3333del, p.Ile1108_Lys1111del), within the highly conserved thioester-containing domain (TED), fully segregating with the familial disease phenotype, as compatible with autosomal recessive inheritance. Complement profiling of the patient showed decreased C3 and FB levels, with elevated levels of the terminal membrane attack complex, while his healthy heterozygous mother showed intermediate levels of C3 consumption. Conclusions Our findings represent the first description of aHUS secondary to a novel homozygous deletion in C3 with ensuing unbalanced C3 over-activation, highlighting a critical role for the disrupted C3-TED domain in the disease mechanism.
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Affiliation(s)
- Shirley Pollack
- Pediatric Nephrology Institute, Ruth Children's Hospital, Haifa, Israel.,Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Israel Eisenstein
- Pediatric Nephrology Institute, Ruth Children's Hospital, Haifa, Israel
| | - Adi Mory
- Genetic Institute, Haifa, Israel
| | | | | | | | | | - Nóra Veszeli
- Research Laboratory, Department of Internal Medicine and Haematology, and MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Dorottya Csuka
- Research Laboratory, Department of Internal Medicine and Haematology, and MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Revital Shemer
- Laboratory of Molecular Medicine, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Fabian Glaser
- Bioinformatics Knowledge Unit, The Lorry I. Lokey Interdisciplinary Center for Life Sciences and Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Zoltán Prohászka
- Research Laboratory, Department of Internal Medicine and Haematology, and MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Daniella Magen
- Pediatric Nephrology Institute, Ruth Children's Hospital, Haifa, Israel.,Laboratory of Molecular Medicine, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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6
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Gavriilaki E, Asteris PG, Touloumenidou T, Koravou EE, Koutra M, Papayanni PG, Karali V, Papalexandri A, Varelas C, Chatzopoulou F, Chatzidimitriou M, Chatzidimitriou D, Veleni A, Grigoriadis S, Rapti E, Chloros D, Kioumis I, Kaimakamis E, Bitzani M, Boumpas D, Tsantes A, Sotiropoulos D, Sakellari I, Kalantzis IG, Parastatidis ST, Koopialipoor M, Cavaleri L, Armaghani DJ, Papadopoulou A, Brodsky RA, Kokoris S, Anagnostopoulos A. Genetic justification of severe COVID-19 using a rigorous algorithm. Clin Immunol 2021; 226:108726. [PMID: 33845193 PMCID: PMC8043057 DOI: 10.1016/j.clim.2021.108726] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 01/04/2023]
Abstract
Recent studies suggest excessive complement activation in severe coronavirus disease-19 (COVID-19). The latter shares common characteristics with complement-mediated thrombotic microangiopathy (TMA). We hypothesized that genetic susceptibility would be evident in patients with severe COVID-19 (similar to TMA) and associated with disease severity. We analyzed genetic and clinical data from 97 patients hospitalized for COVID-19. Through targeted next-generation-sequencing we found an ADAMTS13 variant in 49 patients, along with two risk factor variants (C3, 21 patients; CFH,34 patients). 31 (32%) patients had a combination of these, which was independently associated with ICU hospitalization (p = 0.022). Analysis of almost infinite variant combinations showed that patients with rs1042580 in thrombomodulin and without rs800292 in complement factor H did not require ICU hospitalization. We also observed gender differences in ADAMTS13 and complement-related variants. In light of encouraging results by complement inhibitors, our study highlights a patient population that might benefit from early initiation of specific treatment.
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Affiliation(s)
- Eleni Gavriilaki
- Hematology Department – BMT Unit, G Papanicolaou Hospital, Thessaloniki, Greece,Corresponding author at: Hematology Department – BMT Unit, G. Papanicolaou Hospital, Exochi, 57010, Thessaloniki, Greece
| | - Panagiotis G. Asteris
- Computational Mechanics Laboratory, School of Pedagogical and Technological Education, Athens, Greece
| | | | | | - Maria Koutra
- Hematology Department – BMT Unit, G Papanicolaou Hospital, Thessaloniki, Greece
| | | | - Vassiliki Karali
- Rheumatology and Clinical Immunology Unit, "Attikon" University Hospital, Athens, Greece
| | | | - Christos Varelas
- Hematology Department – BMT Unit, G Papanicolaou Hospital, Thessaloniki, Greece
| | - Fani Chatzopoulou
- Microbiology Department, Aristotle University of Thessaloniki, Greece
| | - Maria Chatzidimitriou
- Biomedical Sciences, Alexander Campus International Hellenic University, Thessaloniki, Greece
| | | | - Anastasia Veleni
- Infectious Disease Committee, G Papanicolaou Hospital, Thessaloniki, Greece
| | - Savvas Grigoriadis
- Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Evdoxia Rapti
- Laboratory of Hematology and Hospital Blood Transfusion Department, University General Hospital “Attikon”, NKUA, Medical School, Greece
| | - Diamantis Chloros
- Pneumonology Department, G Papanicolaou Hospital, Thessaloniki, Greece
| | - Ioannis Kioumis
- Respiratory Failure Department, G Papanicolaou Hospital-Aristotle University of Thessaloniki, Thessaloniki, Greece
| | | | - Milly Bitzani
- 1st Intensive Care Unit, G Papanicolaou Hospital, Thessaloniki, Greece
| | - Dimitrios Boumpas
- Rheumatology and Clinical Immunology Unit, "Attikon" University Hospital, Athens, Greece
| | - Argyris Tsantes
- Laboratory of Hematology and Hospital Blood Transfusion Department, University General Hospital “Attikon”, NKUA, Medical School, Greece
| | | | - Ioanna Sakellari
- Hematology Department – BMT Unit, G Papanicolaou Hospital, Thessaloniki, Greece
| | | | - Stefanos T. Parastatidis
- Computational Mechanics Laboratory, School of Pedagogical and Technological Education, Athens, Greece
| | | | - Liborio Cavaleri
- Department of Civil, Environmental, Aerospace and Materials Engineering, University of Palermo, Palermo, Italy
| | - Danial J. Armaghani
- Department of Civil Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia
| | | | - Robert Alan Brodsky
- Hematology Division, Department of Internal Medicine, Johns Hopkins University, Baltimore, USA
| | - Styliani Kokoris
- Laboratory of Hematology and Hospital Blood Transfusion Department, University General Hospital “Attikon”, NKUA, Medical School, Greece
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de Jong S, Gagliardi G, Garanto A, de Breuk A, Lechanteur YTE, Katti S, van den Heuvel LP, Volokhina EB, den Hollander AI. Implications of genetic variation in the complement system in age-related macular degeneration. Prog Retin Eye Res 2021; 84:100952. [PMID: 33610747 DOI: 10.1016/j.preteyeres.2021.100952] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 12/23/2022]
Abstract
Age-related macular degeneration (AMD) is the main cause of vision loss among the elderly in the Western world. While AMD is a multifactorial disease, the complement system was identified as one of the main pathways contributing to disease risk. The strong link between the complement system and AMD was demonstrated by genetic associations, and by elevated complement activation in local eye tissue and in the systemic circulation of AMD patients. Several complement inhibitors have been and are being explored in clinical trials, but thus far with limited success, leaving the majority of AMD patients without treatment options to date. This indicates that there is still a gap of knowledge regarding the functional implications of the complement system in AMD pathogenesis and how to bring these towards clinical translation. Many different experimental set-ups and disease models have been used to study complement activation in vivo and in vitro, and recently emerging patient-derived induced pluripotent stem cells and genome-editing techniques open new opportunities to study AMD disease mechanisms and test new therapeutic strategies in the future. In this review we provide an extensive overview of methods employed to understand the molecular processes of complement activation in AMD pathogenesis. We discuss the findings, advantages and challenges of each approach and conclude with an outlook on how recent, exciting developments can fill in current knowledge gaps and can aid in the development of effective complement-targeting therapeutic strategies in AMD.
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Affiliation(s)
- Sarah de Jong
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Giuliana Gagliardi
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Alejandro Garanto
- Department of Human Genetics, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Pediatrics, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Amalia Children's Hospital, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Anita de Breuk
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Yara T E Lechanteur
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Suresh Katti
- Gemini Therapeutics Inc., Cambridge, MA, 02139, USA
| | - Lambert P van den Heuvel
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Amalia Children's Hospital, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Laboratory Medicine, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Elena B Volokhina
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Amalia Children's Hospital, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Laboratory Medicine, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Anneke I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Human Genetics, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands.
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8
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Dunne OM, Gao X, Nan R, Gor J, Adamson PJ, Gordon DL, Moulin M, Haertlein M, Forsyth VT, Perkins SJ. A Dimerization Site at SCR-17/18 in Factor H Clarifies a New Mechanism for Complement Regulatory Control. Front Immunol 2021; 11:601895. [PMID: 33552059 PMCID: PMC7859452 DOI: 10.3389/fimmu.2020.601895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/03/2020] [Indexed: 11/15/2022] Open
Abstract
Complement Factor H (CFH), with 20 short complement regulator (SCR) domains, regulates the alternative pathway of complement in part through the interaction of its C-terminal SCR-19 and SCR-20 domains with host cell-bound C3b and anionic oligosaccharides. In solution, CFH forms small amounts of oligomers, with one of its self-association sites being in the SCR-16/20 domains. In order to correlate CFH function with dimer formation and the occurrence of rare disease-associated variants in SCR-16/20, we identified the dimerization site in SCR-16/20. For this, we expressed, in Pichia pastoris, the five domains in SCR-16/20 and six fragments of this with one-three domains (SCR-19/20, SCR-18/20, SCR-17/18, SCR-16/18, SCR-17 and SCR-18). Size-exclusion chromatography suggested that SCR dimer formation occurred in several fragments. Dimer formation was clarified using analytical ultracentrifugation, where quantitative c(s) size distribution analyses showed that SCR-19/20 was monomeric, SCR-18/20 was slightly dimeric, SCR-16/20, SCR-16/18 and SCR-18 showed more dimer formation, and SCR-17 and SCR-17/18 were primarily dimeric with dissociation constants of ~5 µM. The combination of these results located the SCR-16/20 dimerization site at SCR-17 and SCR-18. X-ray solution scattering experiments and molecular modelling fits confirmed the dimer site to be at SCR-17/18, this dimer being a side-by-side association of the two domains. We propose that the self-association of CFH at SCR-17/18 enables higher concentrations of CFH to be achieved when SCR-19/20 are bound to host cell surfaces in order to protect these better during inflammation. Dimer formation at SCR-17/18 clarified the association of genetic variants throughout SCR-16/20 with renal disease.
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Affiliation(s)
- Orla M Dunne
- Division of Biosciences, Department of Structural and Molecular Biology, University College London, London, United Kingdom.,Life Sciences Group, Institut Laue Langevin, Grenoble, France
| | - Xin Gao
- Division of Biosciences, Department of Structural and Molecular Biology, University College London, London, United Kingdom.,Division of Medicine, University College London, London, United Kingdom
| | - Ruodan Nan
- Division of Biosciences, Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Jayesh Gor
- Division of Biosciences, Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Penelope J Adamson
- Department of Microbiology and Infectious Diseases, Flinders Medical Centre and Flinders University, Bedford Park, SA, Australia
| | - David L Gordon
- Department of Microbiology and Infectious Diseases, Flinders Medical Centre and Flinders University, Bedford Park, SA, Australia
| | - Martine Moulin
- Life Sciences Group, Institut Laue Langevin, Grenoble, France
| | | | - V Trevor Forsyth
- Life Sciences Group, Institut Laue Langevin, Grenoble, France.,Faculty of Natural Sciences, Keele University, Staffordshire, United Kingdom
| | - Stephen J Perkins
- Division of Biosciences, Department of Structural and Molecular Biology, University College London, London, United Kingdom
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9
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Sridharan M, Kluge ML, Go RS, Abraham RS, Moyer AM. Challenges in classification of novel CFH variants in patients with atypical hemolytic uremic syndrome. THROMBOSIS UPDATE 2020. [DOI: 10.1016/j.tru.2020.100002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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10
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Kadkhodayi-Kholghi N, Bhatt JS, Gor J, McDermott LC, Gale DP, Perkins SJ. The solution structure of the complement deregulator FHR5 reveals a compact dimer and provides new insights into CFHR5 nephropathy. J Biol Chem 2020; 295:16342-16358. [PMID: 32928961 PMCID: PMC7705313 DOI: 10.1074/jbc.ra120.015132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/06/2020] [Indexed: 11/06/2022] Open
Abstract
The human complement Factor H-related 5 protein (FHR5) antagonizes the main circulating complement regulator Factor H, resulting in the deregulation of complement activation. FHR5 normally contains nine short complement regulator (SCR) domains, but a FHR5 mutant has been identified with a duplicated N-terminal SCR-1/2 domain pair that causes CFHR5 nephropathy. To understand how this duplication causes disease, we characterized the solution structure of native FHR5 by analytical ultracentrifugation and small-angle X-ray scattering. Sedimentation velocity and X-ray scattering indicated that FHR5 was dimeric, with a radius of gyration (Rg ) of 5.5 ± 0.2 nm and a maximum protein length of 20 nm for its 18 domains. This result indicated that FHR5 was even more compact than the main regulator Factor H, which showed an overall length of 26-29 nm for its 20 SCR domains. Atomistic modeling for FHR5 generated a library of 250,000 physically realistic trial arrangements of SCR domains for scattering curve fits. Only compact domain structures in this library fit well to the scattering data, and these structures readily accommodated the extra SCR-1/2 domain pair present in CFHR5 nephropathy. This model indicated that mutant FHR5 can form oligomers that possess additional binding sites for C3b in FHR5. We conclude that the deregulation of complement regulation by the FHR5 mutant can be rationalized by the enhanced binding of FHR5 oligomers to C3b deposited on host cell surfaces. Our FHR5 structures thus explained key features of the mechanism and pathology of CFHR5 nephropathy.
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Affiliation(s)
- Nilufar Kadkhodayi-Kholghi
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Jayesh S Bhatt
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Jayesh Gor
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | | | - Daniel P Gale
- UCL Department of Renal Medicine, Royal Free Hospital, University College London, London, United Kingdom
| | - Stephen J Perkins
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom.
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11
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Tzoumas N, Hallam D, Harris CL, Lako M, Kavanagh D, Steel DHW. Revisiting the role of factor H in age-related macular degeneration: Insights from complement-mediated renal disease and rare genetic variants. Surv Ophthalmol 2020; 66:378-401. [PMID: 33157112 DOI: 10.1016/j.survophthal.2020.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 12/14/2022]
Abstract
Ophthalmologists are long familiar with the eye showing signs of systemic disease, but the association between age-related macular degeneration and abnormal complement activation, common to several renal disorders, has only recently been elucidated. Although complement activation products were identified in drusen almost three decades ago, it was not until the early 21st century that a single-nucleotide polymorphism in the complement factor H gene was identified as a major heritable determinant of age-related macular degeneration, galvanizing global efforts to unravel the pathogenesis of this common disease. Advances in proteomic analyses and familial aggregation studies have revealed distinctive clinical phenotypes segregated by the functional effects of common and rare genetic variants on the mature protein and its splice variant, factor H-like protein 1. The predominance of loss-of-function, N-terminal mutations implicate age-related macular degeneration as a disease of general complement dysregulation, offering several therapeutic avenues for its modulation. Here, we explore the molecular impact of these mutations/polymorphisms on the ability of variant factor H/factor H-like protein 1 to localize to polyanions, pentraxins, proinflammatory triggers, and cell surfaces across ocular and renal tissues and exert its multimodal regulatory functions and their clinical implications. Finally, we critically evaluate key therapeutic and diagnostic efforts in this rapidly evolving field.
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Affiliation(s)
- Nikolaos Tzoumas
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Dean Hallam
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Claire L Harris
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Majlinda Lako
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David Kavanagh
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - David H W Steel
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; Sunderland Eye Infirmary, Sunderland, United Kingdom
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12
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Perkins SJ. Genetic and Protein Structural Evaluation of Atypical Hemolytic Uremic Syndrome and C3 Glomerulopathy. Adv Chronic Kidney Dis 2020; 27:120-127.e4. [PMID: 32553244 DOI: 10.1053/j.ackd.2020.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/26/2020] [Accepted: 03/03/2020] [Indexed: 02/06/2023]
Abstract
Atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G) are associated with loss of regulation of the alternative pathway of complement and its resulting overactivation. As rare diseases, genetic variants leading to aHUS and C3G were previously analysed in relatively low patient numbers. To improve this analysis, data were pooled from six centres. Totals of 610 rare variants for aHUS and 82 for C3G were presented in an interactive database for 13 genes. Using allele frequency comparisons with the Exome Aggregation Consortium as a reference genome, the patients with aHUS showed significantly more protein-altering ultrarare variants (allele frequency <0.01%) in five genes CFH, CFI, CD46, C3, and DGKE. In patients with C3G, the corresponding association was only found for C3 and CFH. Protein structure analyses of these five proteins showed distinct differences in the positioning of these variants in C3 and FH. For aHUS, variants were clustered at the C-terminus of FH and implicated changes in the binding of FH to host cell surfaces. For C3G, variants were clustered at the N-terminal C3b binding site of FH and implicated changes in the fluid-phase regulation of C3b. We discuss the utility of the Web database as a patient resource for clinicians.
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13
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Schröder-Braunstein J, Kirschfink M. Complement deficiencies and dysregulation: Pathophysiological consequences, modern analysis, and clinical management. Mol Immunol 2019; 114:299-311. [PMID: 31421540 DOI: 10.1016/j.molimm.2019.08.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 07/31/2019] [Accepted: 08/03/2019] [Indexed: 02/07/2023]
Abstract
Complement defects are associated with an enhanced risk of a broad spectrum of infectious as well as systemic or local inflammatory and thrombotic disorders. Inherited complement deficiencies have been described for virtually all complement components but can be mimicked by autoantibodies, interfering with the activity of specific complement components, convertases or regulators. While being rare, diseases related to complement deficiencies are often severe with a frequent but not exclusive manifestation during childhood. Whereas defects of early components of the classical pathway significantly increase the risk of autoimmune disorders, lack of components of the terminal pathway as well as of properdin are associated with an enhanced susceptibility to meningococcal infections. The impaired synthesis or function of C1 inhibitor results in the development of hereditary angioedema (HAE). Furthermore, complement dysregulation causes renal disorders such as atypical hemolytic uremic syndrome (aHUS) or C3 glomerulopathy (C3G) but also age-related macular degeneration (AMD). While paroxysmal nocturnal hemoglobinuria (PNH) results from the combined deficiency of the regulatory complement proteins CD55 and CD59, which is caused by somatic mutation of a common membrane anchor, isolated CD55 or CD59 deficiency is associated with the CHAPLE syndrome and polyneuropathy, respectively. Here, we provide an overview on clinical disorders related to complement deficiencies or dysregulation and describe diagnostic strategies required for their comprehensive molecular characterization - a prerequisite for informed decisions on the therapeutic management of these disorders.
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Affiliation(s)
- Jutta Schröder-Braunstein
- University of Heidelberg, Institute of Immunology, Im Neuenheimer Feld 305, 69120 Heidelberg, Germany
| | - Michael Kirschfink
- University of Heidelberg, Institute of Immunology, Im Neuenheimer Feld 305, 69120 Heidelberg, Germany.
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14
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Schönauer R, Seidel A, Grohmann M, Lindner TH, Bergmann C, Halbritter J. Deleterious Impact of a Novel CFH Splice Site Variant in Atypical Hemolytic Uremic Syndrome. Front Genet 2019; 10:465. [PMID: 31156713 PMCID: PMC6530248 DOI: 10.3389/fgene.2019.00465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/30/2019] [Indexed: 12/21/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a heterogeneous disorder characterized by microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and acute kidney injury (AKI). In about 50% of cases, pathogenic variants in genes involved in the innate immune response including complement factors complement factor H (CFH), CFI, CFB, C3, and membrane co-factor protein (MCP/CD46) put patients at risk for uncontrolled activation of the alternative complement pathway. As aHUS is characterized by incomplete penetrance and presence of additional triggers for disease manifestation, genetic variant interpretation is challenging and streamlined functional variant evaluation is urgently needed. Here, we report the case of a 27-year-old female without previous medical and family history who presented with confusion, petechial bleeding, and anuric AKI. Kidney biopsy revealed glomerular thrombotic microangiopathy (TMA). Targeted next generation sequencing identified a paternally transmitted novel heterozygous splice site variant in the CFH gene [c.3134-2A>G; p.Asp1045_Thr1053del] which resulted in a partial in-frame deletion of exon 20 transcript as determined by cDNA analysis. On the protein level, the concomitant loss of 9 amino acids in the short consensus repeat (SCR) domains 17 and 18 of CFH includes a highly conserved cysteine residue, which is assumed to be essential for proper structural folding and protein function. Treatment with steroids, plasmapheresis, and the complement inhibitor eculizumab led to complete hematological and clinical remission after several months and stable renal function up to 6 years later. In conclusion, genetic investigation for pathogenic variants and evaluation of their functional impact, in particular in the case of splice site variants, is clinically relevant and enables not only better molecular understanding but helps to guide therapy with complement inhibitors.
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Affiliation(s)
- Ria Schönauer
- Division of Nephrology, University Hospital Leipzig, Leipzig, Germany
| | - Anna Seidel
- Division of Nephrology, University Hospital Leipzig, Leipzig, Germany
| | - Maik Grohmann
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
| | - Tom H Lindner
- Division of Nephrology, University Hospital Leipzig, Leipzig, Germany
| | | | - Jan Halbritter
- Division of Nephrology, University Hospital Leipzig, Leipzig, Germany
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15
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Berger BE. Atypical hemolytic uremic syndrome: a syndrome in need of clarity. Clin Kidney J 2019; 12:338-347. [PMID: 31198222 PMCID: PMC6543964 DOI: 10.1093/ckj/sfy066] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Indexed: 12/24/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy (TMA) originally understood to be limited to renal and hematopoietic involvement. Whereas aberrations in complement regulatory proteins (CRPs), C3 or complement factor B (CFB) are detected in ∼60% of patients, a complement-derived pathogenesis that reflects dysregulation of the alternative pathway (AP) of complement activation is present in ∼90% of patients. aHUS remains a diagnosis of exclusion. The discovery of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) and its utility in the diagnosis of thrombotic thrombocytopenic purpura (TTP) has resulted in the appreciation that cases of aHUS have been inappropriately diagnosed as TTP. Thus there has been an evolving appreciation of clinical manifestations of aHUS that renders the appellation aHUS misleading. This article will review the pathogenesis and the evolving clinical presentations of aHUS, present a hypothesis that there can be a phenotypic expression of aHUS due to a complement storm in a disorder where direct endothelial damage occurs and discuss future areas of research to more clearly define the clinical spectrum and management of aHUS.
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Affiliation(s)
- Bruce E Berger
- School of Medicine, Case Western Reserve University, Cleveland, OH, USA
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16
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Valoti E, Alberti M, Iatropoulos P, Piras R, Mele C, Breno M, Cremaschi A, Bresin E, Donadelli R, Alizzi S, Amoroso A, Benigni A, Remuzzi G, Noris M. Rare Functional Variants in Complement Genes and Anti-FH Autoantibodies-Associated aHUS. Front Immunol 2019; 10:853. [PMID: 31118930 PMCID: PMC6504697 DOI: 10.3389/fimmu.2019.00853] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/02/2019] [Indexed: 01/06/2023] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by microangiopathic hemolytic anemia, thrombocytopenia and renal failure. It is caused by genetic or acquired defects of the complement alternative pathway. Factor H autoantibodies (anti-FHs) have been reported in 10% of aHUS patients and are associated with the deficiency of factor H-related 1 (FHR1). However, FHR1 deficiency is not enough to cause aHUS, since it is also present in about 5% of Caucasian healthy subjects. In this study we evaluated the prevalence of genetic variants in CFH, CD46, CFI, CFB, C3, and THBD in aHUS patients with anti-FHs, using healthy subjects with FHR1 deficiency, here defined “supercontrols,” as a reference group. “Supercontrols” are more informative than general population because they share at least one risk factor (FHR1 deficiency) with aHUS patients. We analyzed anti-FHs in 305 patients and 30 were positive. The large majority were children (median age: 7.7 [IQR, 6.6–9.9] years) and 83% lacked FHR1 (n = 25, cases) due to the homozygous CFHR3-CFHR1 deletion (n = 20), or the compound heterozygous CFHR3-CFHR1 and CFHR1-CFHR4 deletions (n = 4), or the heterozygous CFHR3-CFHR1 deletion combined with a frameshift mutation in CFHR1 that generates a premature stop codon (n = 1). Of the 960 healthy adult subjects 48 had the FHR1 deficiency (“supercontrols”). Rare likely pathogenetic variants in CFH, THBD, and C3 were found in 24% of cases (n = 6) compared to 2.1% of the “supercontrols” (P-value = 0.005). We also found that the CFH H3 and the CD46GGAAC haplotypes are not associated with anti-FHs aHUS, whereas these haplotypes are enriched in aHUS patients without anti-FHs, which highlights the differences in the genetic basis of the two forms of the disease. Finally, we confirm that common infections are environmental factors that contribute to the development of anti-FHs aHUS in genetically predisposed individuals, which fits with the sharp peak of incidence during scholar-age. Further studies are needed to fully elucidate the complex genetic and environmental factors underlying anti-FHs aHUS and to establish whether the combination of anti-FHs with likely pathogenetic variants or other risk factors influences disease outcome and response to therapies.
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Affiliation(s)
- Elisabetta Valoti
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Marta Alberti
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Paraskevas Iatropoulos
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Rossella Piras
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Caterina Mele
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Matteo Breno
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Alessandra Cremaschi
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Elena Bresin
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Roberta Donadelli
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Silvia Alizzi
- Azienda Ospedaliera-Universitaria, Città della Salute e della Scienza and Department of Medical Sciences, University of Turin, Turin, Italy
| | - Antonio Amoroso
- Azienda Ospedaliera-Universitaria, Città della Salute e della Scienza and Department of Medical Sciences, University of Turin, Turin, Italy
| | - Ariela Benigni
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Giuseppe Remuzzi
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy.,'L. Sacco' Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Marina Noris
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
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17
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Osborne AJ, Nan R, Miller A, Bhatt JS, Gor J, Perkins SJ. Two distinct conformations of factor H regulate discrete complement-binding functions in the fluid phase and at cell surfaces. J Biol Chem 2018; 293:17166-17187. [PMID: 30217822 PMCID: PMC6222095 DOI: 10.1074/jbc.ra118.004767] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/10/2018] [Indexed: 11/06/2022] Open
Abstract
Factor H (FH) is the major regulator of C3b in the alternative pathway of the complement system in immunity. FH comprises 20 short complement regulator (SCR) domains, including eight glycans, and its Y402H polymorphism predisposes those who carry it to age-related macular degeneration. To better understand FH complement binding and self-association, we have studied the solution structures of both the His-402 and Tyr-402 FH allotypes. Analytical ultracentrifugation revealed that up to 12% of both FH allotypes self-associate, and this was confirmed by small-angle X-ray scattering (SAXS), MS, and surface plasmon resonance analyses. SAXS showed that monomeric FH has a radius of gyration (Rg ) of 7.2-7.8 nm and a length of 25 nm. Starting from known structures for the SCR domains and glycans, the SAXS data were fitted using Monte Carlo methods to determine atomistic structures of monomeric FH. The analysis of 29,715 physically realistic but randomized FH conformations resulted in 100 similar best-fit FH structures for each allotype. Two distinct molecular structures resulted that showed either an extended N-terminal domain arrangement with a folded-back C terminus or an extended C terminus and a folded-back N terminus. These two structures are the most accurate to date for glycosylated full-length FH. To clarify FH functional roles in host protection, crystal structures for the FH complexes with C3b and C3dg revealed that the extended N-terminal conformation accounted for C3b fluid-phase regulation, the extended C-terminal conformation accounted for C3d binding, and both conformations accounted for bivalent FH binding to glycosaminoglycans on the target cell surface.
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Affiliation(s)
- Amy J Osborne
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Ruodan Nan
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Ami Miller
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Jayesh S Bhatt
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Jayesh Gor
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Stephen J Perkins
- From the Department of Structural and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, United Kingdom
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18
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Zhao W, Ding Y, Lu J, Zhang T, Chen D, Zhang H, Zeng C, Liu Z, Chen H. Genetic analysis of the complement pathway in C3 glomerulopathy. Nephrol Dial Transplant 2018; 33:1919-1927. [PMID: 29566171 DOI: 10.1093/ndt/gfy033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 01/12/2018] [Indexed: 01/28/2023] Open
Abstract
Background C3 glomerulopathy often presents with a membranoproliferative glomerulonephritis (MPGN) pattern, and is principally caused by unrestricted activation of the complement alternative pathway. Genetic abnormalities of the complement system critically implicate in the pathogenesis of C3 glomerulopathy, but a systemic profile remains open, especially in Asia. Methods In this study, we completed a comprehensive screen of 11 candidate alternative pathway genes by using targeted genomic enrichment and massively parallel sequencing on 43 patients with sporadic C3 glomerulopathy, which were classified as dense deposit disease (DDD; n = 10) and C3 glomerulonephritis (C3GN; n = 33) cases. An additional 24 patients with immune complex-mediated MPGN were also enrolled. Results In total, 4 novel and 16 rare variants were identified: one was classified as likely pathogenic, and the remaining 19 were of uncertain significance. Three variants reportedly led to functional deficiency with supporting evidences. Variants in the CFH, CFI, CD46 and C3 genes were most frequently detected. A defective control of the complement alternative pathway due to hereditary abnormalities was found at frequencies of 50%, 27% and 17% in DDD, C3GN and immune complex-mediated MPGN, respectively. Irrespective of histological type, the patients with likely pathogenic and uncertain significant variants were clinically similar to those without. Conclusions Accurate genetic screening can give rise to progress in understanding the pathogenesis of C3 glomerulopathy, and the correct assignment of pathogenicity classification is of great importance for better patient care and prognostic or therapeutic advice.
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Affiliation(s)
- Weiwei Zhao
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Yin Ding
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.,Division of Nephrology, Jinling Hospital, Southern Medical University, Nanjing, China
| | - Jianping Lu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.,Division of Nephrology, Jinling Hospital, Southern Medical University, Nanjing, China
| | - Tao Zhang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Dacheng Chen
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Haitao Zhang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Caihong Zeng
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Zhihong Liu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.,Division of Nephrology, Jinling Hospital, Southern Medical University, Nanjing, China
| | - Huimei Chen
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
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19
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Lu F, Liu S, Hao Q, Liu L, Zhang J, Chen X, Hu W, Huang P. Association Between Complement Factor C2/C3/CFB/CFH Polymorphisms and Age-Related Macular Degeneration: A Meta-Analysis. Genet Test Mol Biomarkers 2018; 22:526-540. [PMID: 30179527 DOI: 10.1089/gtmb.2018.0110] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Several previous studies have assessed the contribution of polymorphisms in genes encoding the complement factors C2/C3/CFB/CFH with the risk of age-related macular degeneration (AMD), however the results have been inconsistent. We conducted a meta-analysis to systematically review the potential association between complement factor polymorphisms and AMD. METHODS Studies that investigated associations between C2 (rs547154 and rs9332739), C3 (rs1047286), CFB (rs4151667 and rs641153), and CFH (rs551397 and rs2274700) polymorphisms and AMD were identified by searching PubMed, EMBASE, Web of Science, and Cochrane Library databases for articles published prior to January 1, 2018. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to evaluate the association between these polymorphisms and AMD using Stata 12.0 software. Q and I2 statistics were used to evaluate between-study heterogeneity. Publication bias analyses were conducted using Begg's test. We also conducted an ethnic subgroup analysis. RESULTS A total of 53 studies that included data for 53,774 patients and 56,973 healthy controls were evaluated. The pooled ORs for rs551397, rs2274700, rs4151667, rs641153, rs1047286, rs9332739, and rs547154 in the heterozygote model were 0.53 (95% CI: 0.45-0.61), 0.53 (95% CI: 0.40-0.70), 0.54 (95% CI: 0.46-0.63), 0.48 (95% CI: 0.4-0.57), 1.42 (95% CI: 1.22-1.66), 0.5 (95% CI: 0.45-0.56), and 0.52 (95% CI: 0.43-0.62), respectively. CONCLUSION Our findings from this analysis confirmed the protective role of C2/CFB/CFH polymorphisms in the development of AMD, but showed that the single nucleotide polymorphism in C3 was a high-risk factor for AMD. The racial analysis results suggested that the effect of variant alleles was stronger in Caucasians than Asians.
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Affiliation(s)
- Feiteng Lu
- 1 Department of Biochemistry, College of Medicine, Nanchang University , Nanchang, P.R. China
| | - Shuang Liu
- 1 Department of Biochemistry, College of Medicine, Nanchang University , Nanchang, P.R. China
| | - Qingyun Hao
- 1 Department of Biochemistry, College of Medicine, Nanchang University , Nanchang, P.R. China
| | - Lixia Liu
- 2 Department of Internal Medicine, Youhao District People's Hospital , Yichun, P.R. China
| | - Jing Zhang
- 3 Department of Clinical Laboratory, The Second Affiliated Hospital of Nanchang University , Nanchang, P.R. China
| | - Xiaolong Chen
- 4 Department of Epidemiology, School of Public Health, Nanchang University , Nanchang, P.R. China
| | - Wang Hu
- 4 Department of Epidemiology, School of Public Health, Nanchang University , Nanchang, P.R. China
| | - Peng Huang
- 4 Department of Epidemiology, School of Public Health, Nanchang University , Nanchang, P.R. China .,5 Jiangxi Province Key Laboratory of Preventive Medicine, School of Public Health, Nanchang University , Nanchang, P.R. China
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20
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Geerlings MJ, Volokhina EB, de Jong EK, van de Kar N, Pauper M, Hoyng CB, van den Heuvel LP, den Hollander AI. Genotype-phenotype correlations of low-frequency variants in the complement system in renal disease and age-related macular degeneration. Clin Genet 2018; 94:330-338. [PMID: 29888403 PMCID: PMC6175426 DOI: 10.1111/cge.13392] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/24/2018] [Accepted: 06/03/2018] [Indexed: 12/28/2022]
Abstract
Genetic alterations in the complement system have been linked to a variety of diseases, including atypical hemolytic uremic syndrome (aHUS), C3 glomerulopathy (C3G), and age‐related macular degeneration (AMD). We performed sequence analysis of the complement genes complement factor H (CFH), complement factor I (CFI), and complement C3 (C3) in 866 aHUS/C3G and 697 AMD patients. In total, we identified 505 low‐frequency alleles, representing 121 unique variants, of which 51 are novel. CFH contained the largest number of unique low‐frequency variants (n = 64; 53%), followed by C3 (n = 32; 26%) and CFI (n = 25; 21%). A substantial number of variants were found in both patients groups (n = 48; 40%), while 41 (34%) variants were found only in aHUS/C3G and 32 (26%) variants were AMD specific. Genotype‐phenotype correlations between the disease groups identified a higher frequency of protein altering alleles in short consensus repeat 20 (SCR20) of factor H (FH), and in the serine protease domain of factor I (FI) in aHUS/C3G patients. In AMD, a higher frequency of protein‐altering alleles was observed in SCR3, SCR5, and SCR7 of FH, the SRCR domain of FI, and in the MG3 domain of C3. In conclusion, we observed a substantial overlap of variants between aHUS/C3G and AMD; however, there is a distinct clustering of variants within specific domains.
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Affiliation(s)
- M J Geerlings
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - E B Volokhina
- Radboud university medical center, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Department of Pediatric Nephrology, Nijmegen, The Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - E K de Jong
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - N van de Kar
- Radboud university medical center, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Department of Pediatric Nephrology, Nijmegen, The Netherlands
| | - M Pauper
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - C B Hoyng
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - L P van den Heuvel
- Radboud university medical center, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Department of Pediatric Nephrology, Nijmegen, The Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Pediatrics, Department of Growth and Regeneration, University Hospital Leuven, Leuven, Belgium
| | - A I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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21
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Efficacy of eculizumab in severe ADAMTS13-deficient thrombotic thrombocytopenic purpura (TTP) refractory to standard therapies. Transfus Apher Sci 2018; 57:247-249. [PMID: 29567368 DOI: 10.1016/j.transci.2018.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/09/2018] [Accepted: 03/13/2018] [Indexed: 02/06/2023]
Abstract
Thrombotic thrombocytopenic purpura (TTP) is a rare microangiopathic hemolytic anemia (MAHA) defined by mechanical hemolytic anemia, severe thrombocytopenia, and systemic visceral ischemia due to systemic platelet-rich microthrombi. Forty percent of patients with autoimmune TTP experience one or multiple relapses. Patients with refractory TTP are currently managed by corticosteroids, twice-daily PEX, and the anti-CD20 monoclonal antibody rituximab. Herein, we report two cases of severe TTP, refractory to those standard agents. On the basis of the fact that in cases of severe TTP the classical complement pathway is activated, and that the alternative pathway is also involved, both patients underwent eculizumab (anti-C5 monoclonal antibody) therapy. We observed prompt hematological and organ system responses to the eculizumab and the recovery of plasma ADAMTS-13 activity in both cases. Moreover, the fact that both patients discontinued eculizumab, maintaining the response, emphasizes the possibility of its usefulness for limited treatment periods. In conclusion, the diagnostic and therapeutic algorithm in TTP appears complicated by increasing evidence of complement involvement and the eculizumab seems to be a potential agent for refractory patients.
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22
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Osborne AJ, Breno M, Borsa NG, Bu F, Frémeaux-Bacchi V, Gale DP, van den Heuvel LP, Kavanagh D, Noris M, Pinto S, Rallapalli PM, Remuzzi G, Rodríguez de Cordoba S, Ruiz A, Smith RJH, Vieira-Martins P, Volokhina E, Wilson V, Goodship THJ, Perkins SJ. Statistical Validation of Rare Complement Variants Provides Insights into the Molecular Basis of Atypical Hemolytic Uremic Syndrome and C3 Glomerulopathy. THE JOURNAL OF IMMUNOLOGY 2018; 200:2464-2478. [PMID: 29500241 DOI: 10.4049/jimmunol.1701695] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 01/31/2018] [Indexed: 01/02/2023]
Abstract
Atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G) are associated with dysregulation and overactivation of the complement alternative pathway. Typically, gene analysis for aHUS and C3G is undertaken in small patient numbers, yet it is unclear which genes most frequently predispose to aHUS or C3G. Accordingly, we performed a six-center analysis of 610 rare genetic variants in 13 mostly complement genes (CFH, CFI, CD46, C3, CFB, CFHR1, CFHR3, CFHR4, CFHR5, CFP, PLG, DGKE, and THBD) from >3500 patients with aHUS and C3G. We report 371 novel rare variants (RVs) for aHUS and 82 for C3G. Our new interactive Database of Complement Gene Variants was used to extract allele frequency data for these 13 genes using the Exome Aggregation Consortium server as the reference genome. For aHUS, significantly more protein-altering rare variation was found in five genes CFH, CFI, CD46, C3, and DGKE than in the Exome Aggregation Consortium (allele frequency < 0.01%), thus correlating these with aHUS. For C3G, an association was only found for RVs in C3 and the N-terminal C3b-binding or C-terminal nonsurface-associated regions of CFH In conclusion, the RV analyses showed nonrandom distributions over the affected proteins, and different distributions were observed between aHUS and C3G that clarify their phenotypes.
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Affiliation(s)
- Amy J Osborne
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, United Kingdom
| | - Matteo Breno
- Centro di Ricerche Cliniche per le Malattie Rare "Aldo e Cele Daccò," IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri," 24020 Ranica Bergamo, Italy
| | - Nicolo Ghiringhelli Borsa
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Fengxiao Bu
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242.,Medical Genetics Center, Southwest Hospital, Chongqing 400038, China
| | - Véronique Frémeaux-Bacchi
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service d'Immunologie Biologique, 75015 Paris, France
| | - Daniel P Gale
- Centre for Nephrology, Royal Free Hospital, University College London, London NW3 2QG, United Kingdom
| | - Lambertus P van den Heuvel
- Department of Pediatric Nephrology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands.,Department of Pediatric Nephrology, Department of Growth and Regeneration, University Hospital Leuven, 3000 Leuven, Belgium
| | - David Kavanagh
- The National Renal Complement Therapeutics Centre, Newcastle upon Tyne NE1 4LP, United Kingdom.,Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, United Kingdom
| | - Marina Noris
- Centro di Ricerche Cliniche per le Malattie Rare "Aldo e Cele Daccò," IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri," 24020 Ranica Bergamo, Italy
| | - Sheila Pinto
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, 28040 Madrid, Spain
| | - Pavithra M Rallapalli
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, United Kingdom
| | - Giuseppe Remuzzi
- Centro di Ricerche Cliniche per le Malattie Rare "Aldo e Cele Daccò," IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri," 24020 Ranica Bergamo, Italy.,Department of Biomedical and Clinical Sciences, University of Milan, 20122 Milan, Italy; and
| | - Santiago Rodríguez de Cordoba
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, 28040 Madrid, Spain
| | - Angela Ruiz
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, 28040 Madrid, Spain
| | - Richard J H Smith
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Paula Vieira-Martins
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service d'Immunologie Biologique, 75015 Paris, France
| | - Elena Volokhina
- Department of Pediatric Nephrology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Valerie Wilson
- Northern Molecular Genetics Service, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne NE1 3BZ, United Kingdom
| | - Timothy H J Goodship
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, United Kingdom
| | - Stephen J Perkins
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, United Kingdom;
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23
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Cserhalmi M, Uzonyi B, Merle NS, Csuka D, Meusburger E, Lhotta K, Prohászka Z, Józsi M. Functional Characterization of the Disease-Associated N-Terminal Complement Factor H Mutation W198R. Front Immunol 2017; 8:1800. [PMID: 29321782 PMCID: PMC5733548 DOI: 10.3389/fimmu.2017.01800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/30/2017] [Indexed: 12/23/2022] Open
Abstract
Dysregulation of the complement alternative pathway is involved in the pathogenesis of several diseases, including the kidney diseases atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G). In a patient, initially diagnosed with chronic glomerulonephritis, possibly C3G, and who 6 years later had an episode of aHUS, a heterozygous missense mutation leading to a tryptophan to arginine exchange (W198R) in the factor H (FH) complement control protein (CCP) 3 domain has previously been identified. The aim of this study was to clarify the functional relevance of this mutation. To this end, wild-type (FH1-4WT) and mutant (FH1-4W198R) CCPs 1-4 of FH were expressed as recombinant proteins. The FH1-4W198R mutant showed decreased C3b binding compared with FH1-4WT. FH1-4W198R had reduced cofactor and decay accelerating activity compared with the wild-type protein. Hemolysis assays demonstrated impaired capacity of FH1-4W198R to protect rabbit erythrocytes from human complement-mediated lysis, and also to prevent lysis of sheep erythrocytes in human serum induced by a monoclonal antibody binding in FH CCP5 domain, compared with that of FH1-4WT. Thus, the FH W198R exchange results in impaired complement alternative pathway regulation. The heterozygous nature of this mutation in the index patient may explain the manifestation of two diseases, likely due to different triggers leading to complement dysregulation in plasma or on cell surfaces.
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Affiliation(s)
- Marcell Cserhalmi
- MTA-ELTE "Lendület" Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Barbara Uzonyi
- MTA-ELTE Immunology Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Nicolas S Merle
- UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM, Paris, France
| | - Dorottya Csuka
- 3rd Department of Internal Medicine, Semmelweis University, Budapest, Hungary
| | - Edgar Meusburger
- Department of Nephrology and Dialysis, Academic Teaching Hospital Feldkirch, Feldkirch, Austria
| | - Karl Lhotta
- Department of Nephrology and Dialysis, Academic Teaching Hospital Feldkirch, Feldkirch, Austria
| | - Zoltán Prohászka
- 3rd Department of Internal Medicine, Semmelweis University, Budapest, Hungary.,MTA-SE Immunology and Hematology Research Group, Semmelweis University, Budapest, Hungary
| | - Mihály Józsi
- MTA-ELTE "Lendület" Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
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24
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Schnabolk G, Parsons N, Obert E, Annamalai B, Nasarre C, Tomlinson S, Lewin AS, Rohrer B. Delivery of CR2-fH Using AAV Vector Therapy as Treatment Strategy in the Mouse Model of Choroidal Neovascularization. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2017; 9:1-11. [PMID: 29234687 PMCID: PMC5723362 DOI: 10.1016/j.omtm.2017.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/06/2017] [Indexed: 12/12/2022]
Abstract
Complement activation plays a significant role in age-related macular degeneration (AMD) pathogenesis, and polymorphisms interfering with factor H (fH) function, a complement alternative pathway (AP) inhibitor, are associated with increased AMD risk. We have previously validated an AP inhibitor, a fusion protein consisting of a complement receptor 2 fragment linked to the inhibitory domain of fH (CR2-fH) as an efficacious treatment for choroidal neovascularization (CNV) when delivered intravenously. Here we tested an alternative approach of AAV-mediated delivery (AAV5-VMD2-CR2-fH or AAV5-VMD2-mCherry) using subretinal delivery in C57BL/6J mice. Secretion of CR2-fH was confirmed in polarized retinal pigment epithelium (RPE) cells. A safe concentration of AAV5-VMD2-CR2-fH was identified using electroretinography, optical coherence tomography (OCT), RPE morphology, and antibody profiling. One month after gene delivery, CNV was induced using argon laser photocoagulation. OCT assessment demonstrated reduced CNV with AAV5-VMD2-CR2-fH administration. Bioavailability studies revealed that gene-therapy delivered similar levels of CR2-fH to the RPE/choroid as treatment by intravenous injections, and C3a ELISA verified reduced CNV-associated ocular C3a production. These results contribute to existing data illustrating the importance of the AP of complement in CNV development and its potential role in AMD treatment. Demonstration of AAV-vector efficacy opens new avenues for the development of treatment strategies.
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Affiliation(s)
- Gloriane Schnabolk
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Nathaniel Parsons
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Elisabeth Obert
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | | | - Cecile Nasarre
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA.,Ralph H. Johnson VA Medical Center, Division of Research, Charleston, SC 29401, USA
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville FL 32611, USA
| | - Bärbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA.,Ralph H. Johnson VA Medical Center, Division of Research, Charleston, SC 29401, USA
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25
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Fakhouri F, Zuber J, Frémeaux-Bacchi V, Loirat C. Haemolytic uraemic syndrome. Lancet 2017; 390:681-696. [PMID: 28242109 DOI: 10.1016/s0140-6736(17)30062-4] [Citation(s) in RCA: 313] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 10/19/2016] [Accepted: 10/25/2016] [Indexed: 12/17/2022]
Abstract
Haemolytic uraemic syndrome is a form of thrombotic microangiopathy affecting predominantly the kidney and characterised by a triad of thrombocytopenia, mechanical haemolytic anaemia, and acute kidney injury. The term encompasses several disorders: shiga toxin-induced and pneumococcus-induced haemolytic uraemic syndrome, haemolytic uraemic syndrome associated with complement dysregulation or mutation of diacylglycerol kinase ɛ, haemolytic uraemic syndrome related to cobalamin C defect, and haemolytic uraemic syndrome secondary to a heterogeneous group of causes (infections, drugs, cancer, and systemic diseases). In the past two decades, experimental, genetic, and clinical studies have helped to decipher the pathophysiology of these various forms of haemolytic uraemic syndrome and undoubtedly improved diagnostic approaches. Moreover, a specific mechanism-based treatment has been made available for patients affected by atypical haemolytic uraemic syndrome due to complement dysregulation. Such treatment is, however, still absent for several other disease types, including shiga toxin-induced haemolytic uraemic syndrome.
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Affiliation(s)
- Fadi Fakhouri
- Department of Nephrology, Centre Hospitalier Universitaire, and INSERM UMR S1064, Nantes, France
| | - Julien Zuber
- Assistance Publique-Hôpitaux de Paris, Department of Nephrology and Renal Transplantation, Hôpital Necker, Université Paris Descartes, Paris, France
| | - Véronique Frémeaux-Bacchi
- Assistance Publique-Hôpitaux de Paris, Department of Biological Immunology, Hôpital Européen Georges Pompidou, and INSERM UMR S1138, Complément et Maladies, Centre de Recherche des Cordeliers, Paris, France
| | - Chantal Loirat
- Assistance Publique-Hôpitaux de Paris, Department of Pediatric Nephrology, Hôpital Robert Debré, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
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26
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Ekdahl KN, Teramura Y, Hamad OA, Asif S, Duehrkop C, Fromell K, Gustafson E, Hong J, Kozarcanin H, Magnusson PU, Huber-Lang M, Garred P, Nilsson B. Dangerous liaisons: complement, coagulation, and kallikrein/kinin cross-talk act as a linchpin in the events leading to thromboinflammation. Immunol Rev 2017; 274:245-269. [PMID: 27782319 DOI: 10.1111/imr.12471] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Innate immunity is fundamental to our defense against microorganisms. Physiologically, the intravascular innate immune system acts as a purging system that identifies and removes foreign substances leading to thromboinflammatory responses, tissue remodeling, and repair. It is also a key contributor to the adverse effects observed in many diseases and therapies involving biomaterials and therapeutic cells/organs. The intravascular innate immune system consists of the cascade systems of the blood (the complement, contact, coagulation, and fibrinolytic systems), the blood cells (polymorphonuclear cells, monocytes, platelets), and the endothelial cell lining of the vessels. Activation of the intravascular innate immune system in vivo leads to thromboinflammation that can be activated by several of the system's pathways and that initiates repair after tissue damage and leads to adverse reactions in several disorders and treatment modalities. In this review, we summarize the current knowledge in the field and discuss the obstacles that exist in order to study the cross-talk between the components of the intravascular innate immune system. These include the use of purified in vitro systems, animal models and various types of anticoagulants. In order to avoid some of these obstacles we have developed specialized human whole blood models that allow investigation of the cross-talk between the various cascade systems and the blood cells. We in particular stress that platelets are involved in these interactions and that the lectin pathway of the complement system is an emerging part of innate immunity that interacts with the contact/coagulation system. Understanding the resulting thromboinflammation will allow development of new therapeutic modalities.
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Affiliation(s)
- Kristina N Ekdahl
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden.,Linnaeus Center of Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
| | - Yuji Teramura
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden.,Department of Bioengineering, The University of Tokyo, Tokyo, Japan
| | - Osama A Hamad
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden
| | - Sana Asif
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden
| | - Claudia Duehrkop
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden
| | - Karin Fromell
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden
| | - Elisabet Gustafson
- Department of Women's and Children's Health, Uppsala University Hospital, Uppsala, Sweden
| | - Jaan Hong
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden
| | - Huda Kozarcanin
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden
| | - Peetra U Magnusson
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden
| | - Markus Huber-Lang
- Department of Orthopedic Trauma, Hand, Plastic and Reconstructive Surgery, University of Ulm, Ulm, Germany
| | - Peter Garred
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Section 7631, Faculty of Health and Medical Sciences, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Bo Nilsson
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden.
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27
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Xue X, Wu J, Ricklin D, Forneris F, Di Crescenzio P, Schmidt CQ, Granneman J, Sharp TH, Lambris JD, Gros P. Regulator-dependent mechanisms of C3b processing by factor I allow differentiation of immune responses. Nat Struct Mol Biol 2017; 24:643-651. [PMID: 28671664 DOI: 10.1038/nsmb.3427] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/02/2017] [Indexed: 12/26/2022]
Abstract
The complement system labels microbes and host debris for clearance. Degradation of surface-bound C3b is pivotal to direct immune responses and protect host cells. How the serine protease factor I (FI), assisted by regulators, cleaves either two or three distant peptide bonds in the CUB domain of C3b remains unclear. We present a crystal structure of C3b in complex with FI and regulator factor H (FH; domains 1-4 with 19-20). FI binds C3b-FH between FH domains 2 and 3 and a reoriented C3b C-terminal domain and docks onto the first scissile bond, while stabilizing its catalytic domain for proteolytic activity. One cleavage in C3b does not affect its overall structure, whereas two cleavages unfold CUB and dislodge the thioester-containing domain (TED), affecting binding of regulators and thereby determining the number of cleavages. These data explain how FI generates late-stage opsonins iC3b or C3dg in a context-dependent manner, to react to foreign, danger or healthy self signals.
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Affiliation(s)
- Xiaoguang Xue
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Jin Wu
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Daniel Ricklin
- Department of Pathology &Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Federico Forneris
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Patrizia Di Crescenzio
- Department of Pathology &Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Christoph Q Schmidt
- Department of Pathology &Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Joke Granneman
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Thomas H Sharp
- Section Electron Microscopy, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - John D Lambris
- Department of Pathology &Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Piet Gros
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, the Netherlands
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28
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Ferluga J, Kouser L, Murugaiah V, Sim RB, Kishore U. Potential influences of complement factor H in autoimmune inflammatory and thrombotic disorders. Mol Immunol 2017; 84:84-106. [PMID: 28216098 DOI: 10.1016/j.molimm.2017.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 01/01/2023]
Abstract
Complement system homeostasis is important for host self-protection and anti-microbial immune surveillance, and recent research indicates roles in tissue development and remodelling. Complement also appears to have several points of interaction with the blood coagulation system. Deficiency and altered function due to gene mutations and polymorphisms in complement effectors and regulators, including Factor H, have been associated with familial and sporadic autoimmune inflammatory - thrombotic disorders, in which autoantibodies play a part. These include systemic lupus erythematosus, rheumatoid arthritis, atypical haemolytic uremic syndrome, anti-phospholipid syndrome and age-related macular degeneration. Such diseases are generally complex - multigenic and heterogeneous in their symptoms and predisposition/susceptibility. They usually need to be triggered by vascular trauma, drugs or infection and non-complement genetic factors also play a part. Underlying events seem to include decline in peripheral regulatory T cells, dendritic cell, and B cell tolerance, associated with alterations in lymphoid organ microenvironment. Factor H is an abundant protein, synthesised in many cell types, and its reported binding to many different ligands, even if not of high affinity, may influence a large number of molecular interactions, together with the accepted role of Factor H within the complement system. Factor H is involved in mesenchymal stem cell mediated tolerance and also contributes to self-tolerance by augmenting iC3b production and opsonisation of apoptotic cells for their silent dendritic cell engulfment via complement receptor CR3, which mediates anti-inflammatory-tolerogenic effects in the apoptotic cell context. There may be co-operation with other phagocytic receptors, such as complement C1q receptors, and the Tim glycoprotein family, which specifically bind phosphatidylserine expressed on the apoptotic cell surface. Factor H is able to discriminate between self and nonself surfaces for self-protection and anti-microbe defence. Factor H, particularly as an abundant platelet protein, may also modulate blood coagulation, having an anti-thrombotic role. Here, we review a number of interaction pathways in coagulation and in immunity, together with associated diseases, and indicate where Factor H may be expected to exert an influence, based on reports of the diversity of ligands for Factor H.
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Affiliation(s)
- Janez Ferluga
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, United Kingdom
| | - Lubna Kouser
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, United Kingdom
| | - Valarmathy Murugaiah
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, United Kingdom
| | - Robert B Sim
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Uday Kishore
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, United Kingdom.
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29
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Liszewski MK, Java A, Schramm EC, Atkinson JP. Complement Dysregulation and Disease: Insights from Contemporary Genetics. ANNUAL REVIEW OF PATHOLOGY 2017; 12:25-52. [PMID: 27959629 PMCID: PMC6020056 DOI: 10.1146/annurev-pathol-012615-044145] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The vertebrate complement system consists of sequentially interacting proteins that provide for a rapid and powerful host defense. Nearly 60 proteins comprise three activation pathways (classical, alternative, and lectin) and a terminal cytolytic pathway common to all. Attesting to its potency, nearly half of the system's components are engaged in its regulation. An emerging theme over the past decade is that variations in these inhibitors predispose to two scourges of modern humans. One, occurring most often in childhood, is a rare but deadly thrombomicroangiopathy called atypical hemolytic uremic syndrome. The other, age-related macular degeneration, is the most common form of blindness in the elderly. Their seemingly unrelated clinical presentations and pathologies share the common theme of overactivity of the complement system's alternative pathway. This review summarizes insights gained from contemporary genetics for understanding how dysregulation of this powerful innate immune system leads to these human diseases.
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Affiliation(s)
- M Kathryn Liszewski
- Division of Rheumatology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110;
| | - Anuja Java
- Division of Nephrology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | | | - John P Atkinson
- Division of Rheumatology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110;
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30
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Dunne O, Weidenhaupt M, Callow P, Martel A, Moulin M, Perkins SJ, Haertlein M, Forsyth VT. Matchout deuterium labelling of proteins for small-angle neutron scattering studies using prokaryotic and eukaryotic expression systems and high cell-density cultures. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 46:425-432. [PMID: 27844110 PMCID: PMC5486828 DOI: 10.1007/s00249-016-1186-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 10/19/2016] [Accepted: 10/28/2016] [Indexed: 12/17/2022]
Abstract
Small-angle neutron scattering (SANS) is a powerful technique for the characterisation of macromolecular structures and interactions. Its main advantage over other solution state approaches is the ability to use D2O/H2O solvent contrast variation to selectively match out specific parts of a multi-component system. While proteins, nucleic acids, and lipids are readily distinguished in this way, it is not possible to locate different parts of a protein–protein system without the introduction of additional contrast by selective deuteration. Here, we describe new methods by which ‘matchout labelled’ proteins can be produced using Escherichia coli and Pichia pastoris expression systems in high cell-density cultures. The method is designed to produce protein that has a scattering length density that is very close to that of 100% D2O, providing clear contrast when used with hydrogenated partner proteins in a complex. This allows the production of a single sample system for which SANS measurements at different solvent contrasts can be used to distinguish and model the hydrogenated component, the deuterated component, and the whole complex. The approach, which has significant cost advantages, has been extensively tested for both types of expression system.
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Affiliation(s)
- O Dunne
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK.,Institut Laue Langevin, 71 avenue des Martyrs, 38042, Grenoble Cedex 9, France
| | - M Weidenhaupt
- University Grenoble Alpes, CNRS, LMGP, F-38000, Grenoble, France
| | - P Callow
- Institut Laue Langevin, 71 avenue des Martyrs, 38042, Grenoble Cedex 9, France
| | - A Martel
- Institut Laue Langevin, 71 avenue des Martyrs, 38042, Grenoble Cedex 9, France
| | - M Moulin
- Institut Laue Langevin, 71 avenue des Martyrs, 38042, Grenoble Cedex 9, France
| | - S J Perkins
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - M Haertlein
- Institut Laue Langevin, 71 avenue des Martyrs, 38042, Grenoble Cedex 9, France
| | - V T Forsyth
- Institut Laue Langevin, 71 avenue des Martyrs, 38042, Grenoble Cedex 9, France. .,Macromolecular Structure Group, Faculty of Natural Sciences, Keele University, Staffordshire, ST5 5BG, UK.
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31
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Domain structure of human complement C4b extends with increasing NaCl concentration: implications for its regulatory mechanism. Biochem J 2016; 473:4473-4491. [PMID: 27738201 DOI: 10.1042/bcj20160744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 01/06/2023]
Abstract
During the activation of complement C4 to C4b, the exposure of its thioester domain (TED) is crucial for the attachment of C4b to activator surfaces. In the C4b crystal structure, TED forms an Arg104-Glu1032 salt bridge to tether its neighbouring macroglobulin (MG1) domain. Here, we examined the C4b domain structure to test whether this salt bridge affects its conformation. Dual polarisation interferometry of C4b immobilised at a sensor surface showed that the maximum thickness of C4b increased by 0.46 nm with an increase in NaCl concentration from 50 to 175 mM NaCl. Analytical ultracentrifugation showed that the sedimentation coefficient s20,w of monomeric C4b of 8.41 S in 50 mM NaCl buffer decreased to 7.98 S in 137 mM NaCl buffer, indicating that C4b became more extended. Small angle X-ray scattering reported similar RG values of 4.89-4.90 nm for C4b in 137-250 mM NaCl. Atomistic scattering modelling of the C4b conformation showed that TED and the MG1 domain were separated by 4.7 nm in 137-250 mM NaCl and this is greater than that of 4.0 nm in the C4b crystal structure. Our data reveal that in low NaCl concentrations, both at surfaces and in solution, C4b forms compact TED-MG1 structures. In solution, physiologically relevant NaCl concentrations lead to the separation of the TED and MG1 domain, making C4b less capable of binding to its complement regulators. These conformational changes are similar to those seen previously for complement C3b, confirming the importance of this salt bridge for regulating both C4b and C3b.
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32
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Durey MAD, Sinha A, Togarsimalemath SK, Bagga A. Anti-complement-factor H-associated glomerulopathies. Nat Rev Nephrol 2016; 12:563-78. [PMID: 27452363 DOI: 10.1038/nrneph.2016.99] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Atypical haemolytic uraemic syndrome (aHUS), an important cause of acute kidney injury, is characterized by dysregulation of the complement pathway, frequent need for dialysis, and progression to end-stage renal disease. Autoantibodies against complement factor H (FH), the main plasma regulatory protein of the alternative pathway of the complement system, account for a considerable proportion of children with aHUS. The autoantibodies are usually associated with the occurrence of a homozygous deletion in the genes encoding the FH-related proteins FHR1 and FHR3. High levels of autoantibodies, noted at the onset of disease and during relapses, induce functional deficiency of FH, whereas their decline, in response to plasma exchanges and/or immunosuppressive therapy, is associated with disease remission. Management with plasma exchange and immunosuppression is remarkably effective in inducing and maintaining remission in aHUS associated with FH autoantibodies, whereas terminal complement blockade with eculizumab is considered the most effective therapy in other forms of aHUS. Anti-FH autoantibodies are also detected in a small proportion of patients with C3 glomerulopathies, which are characterized by chronic glomerular injury mediated by activation of the alternative complement pathway and predominant C3 deposits on renal histology.
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Affiliation(s)
- Marie-Agnes Dragon Durey
- INSERM UMRS1138, Centre de Recherche des Cordeliers, Université Pierre et Marie Curie, 15 rue de l'ecole de medecine, 75006 Paris, France.,Université Paris Descartes, Paris, France.,Service d'Immunologie Biologique, Hôpital Européen Georges Pompidou, APHP, 20 rue Leblanc, 75015 Paris, France
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
| | - Shambhuprasad Kotresh Togarsimalemath
- INSERM UMRS1138, Centre de Recherche des Cordeliers, Université Pierre et Marie Curie, 15 rue de l'ecole de medecine, 75006 Paris, France.,Université Paris Descartes, Paris, France
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
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33
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Ram S, Shaughnessy J, DeOliveira RB, Lewis LA, Gulati S, Rice PA. Utilizing complement evasion strategies to design complement-based antibacterial immunotherapeutics: Lessons from the pathogenic Neisseriae. Immunobiology 2016; 221:1110-23. [PMID: 27297292 DOI: 10.1016/j.imbio.2016.05.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 05/27/2016] [Indexed: 12/30/2022]
Abstract
Novel therapies are urgently needed to combat the global threat of multidrug-resistant pathogens. Complement forms an important arm of innate defenses against infections. In physiological conditions, complement activation is tightly controlled by soluble and membrane-associated complement inhibitors, but must be selectively activated on invading pathogens to facilitate microbial clearance. Many pathogens, including Neisseria gonorrhoeae and N. meningitidis, express glycans, including N-acetylneuraminic acid (Neu5Ac), that mimic host structures to evade host immunity. Neu5Ac is a negatively charged 9-cabon sugar that inhibits complement, in part by enhancing binding of the complement inhibitor factor H (FH) through C-terminal domains (19 and 20) on FH. Other microbes also bind FH, in most instances through FH domains 6 and 7 or 18-20. Here we describe two strategies to target complement activation on Neisseriae. First, microbial binding domains of FH were fused to IgG Fc to create FH18-20/Fc (binds gonococci) and FH6,7/Fc (binds meningococci). A point mutation in FH domain 19 eliminated hemolysis caused by unmodified FH18-20, but retained binding to gonococci. FH18-20/Fc and FH6,7/Fc mediated complement-dependent killing in vitro and showed efficacy in animal models of gonorrhea and meningococcal bacteremia, respectively. The second strategy utilized CMP-nonulosonate (CMP-NulO) analogs of sialic acid that were incorporated into LOS and prevented complement inhibition by physiologic CMP-Neu5Ac and resulted in attenuated gonococcal infection in mice. While studies to establish the safety of these agents are needed, enhancing complement activation on microbes may represent a promising strategy to treat antimicrobial resistant organisms.
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Affiliation(s)
- Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Rosane B DeOliveira
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Lisa A Lewis
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sunita Gulati
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Peter A Rice
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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34
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Ricklin D, Reis ES, Lambris JD. Complement in disease: a defence system turning offensive. Nat Rev Nephrol 2016; 12:383-401. [PMID: 27211870 DOI: 10.1038/nrneph.2016.70] [Citation(s) in RCA: 369] [Impact Index Per Article: 46.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Although the complement system is primarily perceived as a host defence system, a more versatile, yet potentially more harmful side of this innate immune pathway as an inflammatory mediator also exists. The activities that define the ability of the complement system to control microbial threats and eliminate cellular debris - such as sensing molecular danger patterns, generating immediate effectors, and extensively coordinating with other defence pathways - can quickly turn complement from a defence system to an aggressor that drives immune and inflammatory diseases. These host-offensive actions become more pronounced with age and are exacerbated by a variety of genetic factors and autoimmune responses. Complement can also be activated inappropriately, for example in response to biomaterials or transplants. A wealth of research over the past two decades has led to an increasingly finely tuned understanding of complement activation, identified tipping points between physiological and pathological behaviour, and revealed avenues for therapeutic intervention. This Review summarizes our current view of the key activating, regulatory, and effector mechanisms of the complement system, highlighting important crosstalk connections, and, with an emphasis on kidney disease and transplantation, discusses the involvement of complement in clinical conditions and promising therapeutic approaches.
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Affiliation(s)
- Daniel Ricklin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, 401 Stellar Chance, 422 Curie Boulevard, Philadelphia, Pennsylvania 19104, USA
| | - Edimara S Reis
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, 401 Stellar Chance, 422 Curie Boulevard, Philadelphia, Pennsylvania 19104, USA
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, 401 Stellar Chance, 422 Curie Boulevard, Philadelphia, Pennsylvania 19104, USA
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35
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Berger BE. The Alternative Pathway of Complement and the Evolving Clinical-Pathophysiological Spectrum of Atypical Hemolytic Uremic Syndrome. Am J Med Sci 2016; 352:177-90. [PMID: 27524217 DOI: 10.1016/j.amjms.2016.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 03/31/2016] [Accepted: 05/03/2016] [Indexed: 01/31/2023]
Abstract
Complement-mediated atypical hemolytic uremic syndrome (aHUS) comprises approximately 90% of cases of aHUS, and results from dysregulation of endothelial-anchored complement activation with resultant endothelial damage. The discovery of biomarker ADAMTS13 has enabled a more accurate diagnosis of thrombotic thrombocytopenic purpura (TTP) and an appreciation of overlapping clinical features of TTP and aHUS. Given our present understanding of the pathogenic pathways involved in aHUS, it is unlikely that a specific test will be developed. Rather the use of biomarker data, complement functional analyses, genomic analyses and clinical presentation will be required to diagnose aHUS. This approach would serve to clarify whether a thrombotic microangiopathy present in a complement-amplifying condition arises from the unmasking of a genetically driven aHUS versus a time-limited complement storm-mediated aHUS due to direct endothelial damage in which no genetic predisposition is present. Although both scenarios result in the phenotypic expression of aHUS and involve the alternate pathway of complement activation, long-term management would differ.
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Affiliation(s)
- Bruce E Berger
- School of Medicine, Case Western Reserve University, Cleveland, Ohio.
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36
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Probing the solution structure of Factor H using hydroxyl radical protein footprinting and cross-linking. Biochem J 2016; 473:1805-19. [PMID: 27099340 DOI: 10.1042/bcj20160225] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 04/19/2016] [Indexed: 11/17/2022]
Abstract
The control protein Factor H (FH) is a crucial regulator of the innate immune complement system, where it is active on host cell membranes and in the fluid phase. Mutations impairing the binding capacity of FH lead to severe autoimmune diseases. Here, we studied the solution structure of full-length FH, in its free state and bound to the C3b complement protein. To do so, we used two powerful techniques, hydroxyl radical protein footprinting (HRPF) and chemical cross-linking coupled with mass spectrometry (MS), to probe the structural rearrangements and to identify protein interfaces. The footprint of C3b on the FH surface matches existing crystal structures of C3b complexed with the N- and C-terminal fragments of FH. In addition, we revealed the position of the central portion of FH in the protein complex. Moreover, cross-linking studies confirmed the involvement of the C-terminus in the dimerization of FH.
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37
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Disease Recurrence After Early Discontinuation of Eculizumab in a Patient With Atypical Hemolytic Uremic Syndrome With Complement C3 I1157T Mutation. J Pediatr Hematol Oncol 2016; 38:e137-9. [PMID: 26840081 DOI: 10.1097/mph.0000000000000505] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Eculizumab, terminal complement inhibitor, has become the frontline treatment for atypical hemolytic uremic syndrome (aHUS). However, the optimal treatment schedule has not yet been established. We describe here an aHUS patient with a mutation of C3 I1157T who achieved remission with eculizumab and suffered a recurrence after eculizumab discontinuation, a clinical situation that has not been previously described in patients with C3 mutation. A 9-year-old male experienced an onset of aHUS after viral gastroenteritis and was treated with hemodialysis. At 13 years of age he developed bacterial enterocolitis due to Campylobacter jejuni and experienced a recurrence of aHUS. Eculizumab was initiated on day 4 after disease onset resulting in recovering laboratory parameters. The patient received eculizumab for 5 months before its discontinuation. Second relapse induced by bacterial pharyngitis was confirmed 4 months after eculizumab discontinuation and prompt eculizumab reinitiation resulted in rapid remission. The patients carrying mutations in CFH or C3 have a high frequency of relapse and worse prognosis. More than 50% of aHUS relapses occurred during the first year after the onset. Therefore, long-term treatment with eculizumab is appropriate in patients with aHUS who have experienced a relapse or have mutations associated with poor prognosis.
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38
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39
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Forneris F, Wu J, Xue X, Ricklin D, Lin Z, Sfyroera G, Tzekou A, Volokhina E, Granneman JC, Hauhart R, Bertram P, Liszewski MK, Atkinson JP, Lambris JD, Gros P. Regulators of complement activity mediate inhibitory mechanisms through a common C3b-binding mode. EMBO J 2016; 35:1133-49. [PMID: 27013439 PMCID: PMC4868954 DOI: 10.15252/embj.201593673] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 02/29/2016] [Indexed: 01/17/2023] Open
Abstract
Regulators of complement activation (RCA) inhibit complement‐induced immune responses on healthy host tissues. We present crystal structures of human RCA (MCP, DAF, and CR1) and a smallpox virus homolog (SPICE) bound to complement component C3b. Our structural data reveal that up to four consecutive homologous CCP domains (i–iv), responsible for inhibition, bind in the same orientation and extended arrangement at a shared binding platform on C3b. Large sequence variations in CCP domains explain the diverse C3b‐binding patterns, with limited or no contribution of some individual domains, while all regulators show extensive contacts with C3b for the domains at the third site. A variation of ~100° rotation around the longitudinal axis is observed for domains binding at the fourth site on C3b, without affecting the overall binding mode. The data suggest a common evolutionary origin for both inhibitory mechanisms, called decay acceleration and cofactor activity, with variable C3b binding through domains at sites ii, iii, and iv, and provide a framework for understanding RCA disease‐related mutations and immune evasion.
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Affiliation(s)
- Federico Forneris
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science Utrecht University, Utrecht, The Netherlands
| | - Jin Wu
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science Utrecht University, Utrecht, The Netherlands
| | - Xiaoguang Xue
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science Utrecht University, Utrecht, The Netherlands
| | - Daniel Ricklin
- Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Zhuoer Lin
- Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Georgia Sfyroera
- Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Apostolia Tzekou
- Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Elena Volokhina
- Department of Pediatric Nephrology (830), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joke Cm Granneman
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science Utrecht University, Utrecht, The Netherlands
| | - Richard Hauhart
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO, USA
| | - Paula Bertram
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO, USA
| | - M Kathryn Liszewski
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO, USA
| | - John P Atkinson
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, MO, USA
| | - John D Lambris
- Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Piet Gros
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science Utrecht University, Utrecht, The Netherlands
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40
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Nozal P, Bernabéu-Herrero ME, Uzonyi B, Szilágyi Á, Hyvärinen S, Prohászka Z, Jokiranta TS, Sánchez-Corral P, López-Trascasa M, Józsi M. Heterogeneity but individual constancy of epitopes, isotypes and avidity of factor H autoantibodies in atypical hemolytic uremic syndrome. Mol Immunol 2016; 70:47-55. [DOI: 10.1016/j.molimm.2015.12.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 11/30/2015] [Accepted: 12/02/2015] [Indexed: 01/27/2023]
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41
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Shaughnessy J, Gulati S, Agarwal S, Unemo M, Ohnishi M, Su XH, Monks BG, Visintin A, Madico G, Lewis LA, Golenbock DT, Reed GW, Rice PA, Ram S. A Novel Factor H-Fc Chimeric Immunotherapeutic Molecule against Neisseria gonorrhoeae. THE JOURNAL OF IMMUNOLOGY 2016; 196:1732-40. [PMID: 26773149 DOI: 10.4049/jimmunol.1500292] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 12/07/2015] [Indexed: 01/10/2023]
Abstract
Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection gonorrhea, has developed resistance to almost every conventional antibiotic. There is an urgent need to develop novel therapies against gonorrhea. Many pathogens, including N. gonorrhoeae, bind the complement inhibitor factor H (FH) to evade complement-dependent killing. Sialylation of gonococcal lipooligosaccharide, as occurs in vivo, augments binding of human FH through its domains 18-20 (FH18-20). We explored the use of fusing FH18-20 with IgG Fc (FH18-20/Fc) to create a novel anti-infective immunotherapeutic. FH18-20 also binds to select host glycosaminoglycans to limit unwanted complement activation on host cells. To identify mutation(s) in FH18-20 that eliminated complement activation on host cells, yet maintained binding to N. gonorrhoeae, we created four mutations in domains 19 or 20 described in atypical hemolytic uremic syndrome that prevented binding of mutated fH to human erythrocytes. One of the mutant proteins (D to G at position 1119 in domain 19; FHD1119G/Fc) facilitated complement-dependent killing of gonococci similar to unmodified FH18-20/Fc but, unlike FH18-20/Fc, did not lyse human erythrocytes. FHD1119G/Fc bound to all (100%) of 15 sialylated clinical N. gonorrhoeae isolates tested (including three contemporary ceftriaxone-resistant strains), mediated complement-dependent killing of 10 of 15 (67%) strains, and enhanced C3 deposition (≥10-fold above baseline levels) on each of the five isolates not directly killed by complement. FHD1119G/Fc facilitated opsonophagocytic killing of a serum-resistant strain by human polymorphonuclear neutrophils. FHD1119G/Fc administered intravaginally significantly reduced the duration and burden of gonococcal infection in the mouse vaginal colonization model. FHD1119G/Fc represents a novel immunotherapeutic against multidrug-resistant N. gonorrhoeae.
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Affiliation(s)
- Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester MA 01605
| | - Sunita Gulati
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester MA 01605
| | - Sarika Agarwal
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester MA 01605
| | - Magnus Unemo
- World Health Organization Collaborating Centre for Gonorrhoea and Other Sexually Transmitted Infections, Department of Laboratory Medicine and Microbiology, Orebro University Hospital, SE-701 85 Orebro, Sweden
| | - Makoto Ohnishi
- National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Xia-Hong Su
- Institute of Dermatology, Chinese Academy of Medical Sciences, Peking Union Medical College, Nanjing 210042, China
| | - Brian G Monks
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester MA 01605; Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany
| | - Alberto Visintin
- Centers for Therapeutic Innovation, Pfizer, Inc., Cambridge, MA 02139
| | - Guillermo Madico
- Section of Infectious Diseases, Boston Medical Center, Boston, MA 02118; and
| | - Lisa A Lewis
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester MA 01605
| | - Douglas T Golenbock
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester MA 01605
| | - George W Reed
- Preventive and Behavioral Medicine, University of Massachusetts Medical School, Worcester MA 01605
| | - Peter A Rice
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester MA 01605
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester MA 01605;
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42
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Loeven MA, Rops AL, Lehtinen MJ, van Kuppevelt TH, Daha MR, Smith RJ, Bakker M, Berden JH, Rabelink TJ, Jokiranta TS, van der Vlag J. Mutations in Complement Factor H Impair Alternative Pathway Regulation on Mouse Glomerular Endothelial Cells in Vitro. J Biol Chem 2016; 291:4974-81. [PMID: 26728463 DOI: 10.1074/jbc.m115.702506] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Indexed: 01/28/2023] Open
Abstract
Complement factor H (FH) inhibits complement activation and interacts with glomerular endothelium via its complement control protein domains 19 and 20, which also recognize heparan sulfate (HS). Abnormalities in FH are associated with the renal diseases atypical hemolytic uremic syndrome and dense deposit disease and the ocular disease age-related macular degeneration. Although FH systemically controls complement activation, clinical phenotypes selectively manifest in kidneys and eyes, suggesting the presence of tissue-specific determinants of disease development. Recent results imply the importance of tissue-specifically expressed, sulfated glycosaminoglycans (GAGs), like HS, in determining FH binding to and activity on host tissues. Therefore, we investigated which GAGs mediate human FH and recombinant human FH complement control proteins domains 19 and 20 (FH19-20) binding to mouse glomerular endothelial cells (mGEnCs) in ELISA. Furthermore, we evaluated the functional defects of FH19-20 mutants during complement activation by measuring C3b deposition on mGEnCs using flow cytometry. FH and FH19-20 bound dose-dependently to mGEnCs and TNF-α treatment increased binding of both proteins, whereas heparinase digestion and competition with heparin/HS inhibited binding. Furthermore, 2-O-, and 6-O-, but not N-desulfation of heparin, significantly increased the inhibitory effect on FH19-20 binding to mGEnCs. Compared with wild type FH19-20, atypical hemolytic uremic syndrome-associated mutants were less able to compete with FH in normal human serum during complement activation on mGEnCs, confirming their potential glomerular pathogenicity. In conclusion, our study shows that FH and FH19-20 binding to glomerular endothelial cells is differentially mediated by HS but not other GAGs. Furthermore, we describe a novel, patient serum-independent competition assay for pathogenicity screening of FH19-20 mutants.
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Affiliation(s)
- Markus A Loeven
- From the Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Angelique L Rops
- From the Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Markus J Lehtinen
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, FIN-00290 Helsinki, Finland
| | - Toin H van Kuppevelt
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - Mohamed R Daha
- Department of Nephrology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands, and
| | - Richard J Smith
- Department of Internal Medicine and Otolaryngology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Marinka Bakker
- From the Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Jo H Berden
- From the Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Ton J Rabelink
- Department of Nephrology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands, and
| | - T Sakari Jokiranta
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, FIN-00290 Helsinki, Finland
| | - Johan van der Vlag
- From the Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands,
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Bajic G, Degn SE, Thiel S, Andersen GR. Complement activation, regulation, and molecular basis for complement-related diseases. EMBO J 2015; 34:2735-57. [PMID: 26489954 DOI: 10.15252/embj.201591881] [Citation(s) in RCA: 243] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 09/28/2015] [Indexed: 01/13/2023] Open
Abstract
The complement system is an essential element of the innate immune response that becomes activated upon recognition of molecular patterns associated with microorganisms, abnormal host cells, and modified molecules in the extracellular environment. The resulting proteolytic cascade tags the complement activator for elimination and elicits a pro-inflammatory response leading to recruitment and activation of immune cells from both the innate and adaptive branches of the immune system. Through these activities, complement functions in the first line of defense against pathogens but also contributes significantly to the maintenance of homeostasis and prevention of autoimmunity. Activation of complement and the subsequent biological responses occur primarily in the extracellular environment. However, recent studies have demonstrated autocrine signaling by complement activation in intracellular vesicles, while the presence of a cytoplasmic receptor serves to detect complement-opsonized intracellular pathogens. Furthermore, breakthroughs in both functional and structural studies now make it possible to describe many of the intricate molecular mechanisms underlying complement activation and the subsequent downstream events, as well as its cross talk with, for example, signaling pathways, the coagulation system, and adaptive immunity. We present an integrated and updated view of complement based on structural and functional data and describe the new roles attributed to complement. Finally, we discuss how the structural and mechanistic understanding of the complement system rationalizes the genetic defects conferring uncontrolled activation or other undesirable effects of complement.
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Affiliation(s)
- Goran Bajic
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Søren E Degn
- Department of Biomedicine, Aarhus University, Aarhus, Denmark Program in Cellular and Molecular Medicine, Children's Hospital, Boston, MA, USA
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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Confirmation of Host Genetic Determinants in the CFH Region and Susceptibility to Meningococcal Disease in a Central European Study Sample. Pediatr Infect Dis J 2015; 34:1115-7. [PMID: 26135246 DOI: 10.1097/inf.0000000000000823] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Invasive meningococcal disease (IMD) is a leading cause of meningitis and severe sepsis in children and adolescents. Genetic factors are important in determining the susceptibility to and outcome of IMD. Recently, a genome-wide association study from the United Kingdom showed significant associations of single-nucleotide polymorphisms within complement factor H (CFH; rs1065489) and in CFH-related protein 3 (rs426736) with susceptibility of IMD. We report data of a genetic replication study in Central European children. METHODS The study was conducted as a retrospective case-reference study involving 248 patients with confirmed diagnosis of IMD from Austria and Germany and 835 healthy reference individuals from a multicenter German birth cohort. RESULTS Carriers of the minor alleles of rs1065489 and rs426736 were at lower risk of IMD [allelic odds ratio = 0.60 (0.44-0.82); P = 0.001 and 0.61 (0.45-0.83); P = 0.001]. Also, 2 major haplotypes (GT and TC) derived from the 2 single-nucleotide polymorphisms were significantly associated with IMD (P = 0.001 and P = 0.003, respectively). CONCLUSIONS The consistency of the results between the genome-wide association study and our study population strengthens the association of CFH polymorphisms to the susceptibility of IMD. Our results support the conclusion that CFH is a critical determinant in acquiring meningococcal disease.
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Mutational analysis of Kaposica reveals that bridging of MG2 and CUB domains of target protein is crucial for the cofactor activity of RCA proteins. Proc Natl Acad Sci U S A 2015; 112:12794-9. [PMID: 26420870 DOI: 10.1073/pnas.1506449112] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The complement system has evolved to annul pathogens, but its improper regulation is linked with diseases. Efficient regulation of the system is primarily provided by a family of proteins termed regulators of complement activation (RCA). The knowledge of precise structural determinants of RCA proteins critical for imparting the regulatory activities and the molecular events underlying the regulatory processes, nonetheless, is still limited. Here, we have dissected the structural requirements of RCA proteins that are crucial for one of their two regulatory activities, the cofactor activity (CFA), by using the Kaposi's sarcoma-associated herpesvirus RCA homolog Kaposica as a model protein. We have scanned the entire Kaposica molecule by sequential mutagenesis using swapping and site-directed mutagenesis, which identified residues critical for its interaction with C3b and factor I. Mapping of these residues onto the modeled structure of C3b-Kaposica-factor I complex supported the mutagenesis data. Furthermore, the model suggested that the C3b-interacting residues bridge the CUB (complement C1r-C1s, Uegf, Bmp1) and MG2 (macroglobulin-2) domains of C3b. Thus, it seems that stabilization of the CUB domain with respect to the core of the C3b molecule is central for its CFA. Identification of CFA-critical regions in Kaposica guided experiments in which the equivalent regions of membrane cofactor protein were swapped into decay-accelerating factor. This strategy allowed CFA to be introduced into decay-accelerating factor, suggesting that viral and human regulators use a common mechanism for CFA.
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Oymak Y, Karapınar TH, Ay Y, Özcan E, Müminoğlu N, Aydın Köker S, Töret E, Berdeli A, Serdaroğlu E, Vergin C. Thrombotic Microangiopathy with Complement Factor H Gene Mutations Unassociated with Atypical Hemolytic Uremic Syndrome. Turk J Haematol 2015; 32:275-6. [PMID: 26376595 PMCID: PMC4563206 DOI: 10.4274/tjh.2015.0084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Yeşim Oymak
- Dr. Behçet Uz Children's Hospital, Clinic of Hematology, İzmir, Turkey Phone: +90 532 355 42 28 E-mail:
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Liszewski MK, Atkinson JP. Complement regulator CD46: genetic variants and disease associations. Hum Genomics 2015; 9:7. [PMID: 26054645 PMCID: PMC4469999 DOI: 10.1186/s40246-015-0029-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 05/26/2015] [Indexed: 12/23/2022] Open
Abstract
Membrane cofactor protein (MCP; CD46) is an ubiquitously expressed complement regulatory protein that protects host cells from injury by complement. This type-I membrane glycoprotein serves as a cofactor for the serine protease factor I to mediate inactivation of C3b and C4b deposited on host cells. More than 60 disease-associated mutations in MCP have now been identified. The majority of the mutations are linked to a rare thrombotic microangiopathic-based disease, atypical hemolytic uremic syndrome (aHUS), but new putative links to systemic lupus erythematosus, glomerulonephritis, and pregnancy-related disorders among others have also been identified. This review summarizes our current knowledge of disease-associated mutations in this complement inhibitor.
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Affiliation(s)
- M Kathryn Liszewski
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, 660 South Euclid, Saint Louis, MO, 63110, USA.
| | - John P Atkinson
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, 660 South Euclid, Saint Louis, MO, 63110, USA.
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Sfyroera G, Ricklin D, Reis ES, Chen H, Wu EL, Kaznessis YN, Ekdahl KN, Nilsson B, Lambris JD. Rare loss-of-function mutation in complement component C3 provides insight into molecular and pathophysiological determinants of complement activity. THE JOURNAL OF IMMUNOLOGY 2015; 194:3305-16. [PMID: 25712219 DOI: 10.4049/jimmunol.1402781] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The plasma protein C3 is a central element in the activation and effector functions of the complement system. A hereditary dysfunction of C3 that prevents complement activation via the alternative pathway (AP) was described previously in a Swedish family, but its genetic cause and molecular consequences have remained elusive. In this study, we provide these missing links by pinpointing the dysfunction to a point mutation in the β-chain of C3 (c.1180T > C; p.Met(373)Thr). In the patient's plasma, AP activity was completely abolished and could only be reconstituted with the addition of normal C3. The M373T mutation was localized to the macroglobulin domain 4 of C3, which contains a binding site for the complement inhibitor compstatin and is considered critical for the interaction of C3 with the AP C3 convertase. Structural analyses suggested that the mutation disturbs the integrity of macroglobulin domain 4 and induces conformational changes that propagate into adjacent regions. Indeed, C3 M373T showed an altered binding pattern for compstatin and surface-bound C3b, and the presence of Thr(373) in either the C3 substrate or convertase-affiliated C3b impaired C3 activation and opsonization. In contrast to known gain-of-function mutations in C3, patients affected by this loss-of-function mutation did not develop familial disease, but rather showed diverse and mostly episodic symptoms. Our study therefore reveals the molecular mechanism of a relevant loss-of-function mutation in C3 and provides insight into the function of the C3 convertase, the differential involvement of C3 activity in clinical conditions, and some potential implications of therapeutic complement inhibition.
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Affiliation(s)
- Georgia Sfyroera
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Daniel Ricklin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Edimara S Reis
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Hui Chen
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Emilia L Wu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
| | - Yiannis N Kaznessis
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
| | - Kristina N Ekdahl
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala, Sweden; and Linnæus Center of Biomaterials Chemistry, Linnæus University, SE-391 82 Kalmar, Sweden
| | - Bo Nilsson
- Linnæus Center of Biomaterials Chemistry, Linnæus University, SE-391 82 Kalmar, Sweden
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104;
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Spectrum and management of complement immunodeficiencies (excluding hereditary angioedema) across Europe. J Clin Immunol 2015; 35:199-205. [PMID: 25663093 DOI: 10.1007/s10875-015-0137-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 01/28/2015] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Complement immunodeficiencies (excluding hereditary angioedema and mannose binding lectin deficiency) are rare. Published literature consists largely of case reports and small series. We collated data from 18 cities across Europe to provide an overview of primarily homozygous, rather than partial genotypes and their impact and management. METHODS Patients were recruited through the ESID registry. Clinical and laboratory information was collected onto standardized forms and analyzed using SPSS software. RESULTS Seventy-seven patients aged 1 to 68 years were identified. 44 % presented in their first decade of life. 29 % had C2 deficiency, defects in 11 other complement factors were found. 50 (65 %) had serious invasive infections. 61 % of Neisseria meningitidis infections occurred in patients with terminal pathway defects, while 74 % of Streptococcus pneumoniae infections occurred in patients with classical pathway defects (p < 0.001). Physicians in the UK were more likely to prescribe antibiotic prophylaxis than colleagues on the Continent for patients with classical pathway defects. After diagnosis, 16 % of patients suffered serious bacterial infections. Age of the patient and use of prophylactic antibiotics were not associated with subsequent infection risk. Inflammatory/autoimmune diseases were not seen in patients with terminal pathway, but in one third of patients classical and alternative pathway defects. CONCLUSION The clinical phenotypes of specific complement immunodeficiencies vary considerably both in terms of the predominant bacterial pathogen, and the risk and type of auto-inflammatory disease. Appreciation of these phenotypic differences should help both immunologists and other specialists in their diagnosis and management of these rare and complex patients.
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50
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Alasfar S, Alachkar N. Atypical hemolytic uremic syndrome post-kidney transplantation: two case reports and review of the literature. Front Med (Lausanne) 2014; 1:52. [PMID: 25593925 PMCID: PMC4292050 DOI: 10.3389/fmed.2014.00052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 11/29/2014] [Indexed: 01/09/2023] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare disorder characterized by over-activation and dysregulation of the alternative complement pathway. Its estimated prevalence is 1–2 per million. The disease is characterized by thrombotic microangiopathy, which causes anemia, thrombocytopenia, and acute renal failure. aHUS has more severe course compared to typical (infection-induced) HUS and is frequently characterized by relapses that leads to end stage renal disease. For a long time, kidney transplantation for these patients was contraindicated because of high rate of recurrence and subsequent renal graft loss. The post-kidney transplantation recurrence rate largely depends on the pathogenetic mechanisms involved. However, over the past several years, advancements in the understanding and therapeutics of aHUS have allowed successful kidney transplantation in these patients. Eculizumab, which is a complement C5 antibody that inhibits complement factor 5a and subsequent formation of the membrane-attack complex, has been used in prevention and treatment of post-transplant aHUS recurrence. In this paper, we present two new cases of aHUS patients who underwent successful kidney transplantation in our center with the use of prophylactic and maintenance eculizumab therapy that have not been published before. The purpose of reporting these two cases is to emphasize the importance of using eculizumab as a prophylactic therapy to prevent aHUS recurrence post-transplant in high-risk patients. We will also review the current understanding of the genetics of aHUS, the pathogenesis of its recurrence after kidney transplantation, and strategies for prevention and treatment of post-transplant aHUS recurrence.
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Affiliation(s)
- Sami Alasfar
- Department of Medicine, Division of Nephrology, The Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Nada Alachkar
- Department of Medicine, Division of Nephrology, The Johns Hopkins University School of Medicine , Baltimore, MD , USA
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