1
|
Götz MP, Duque Villegas MA, Fageräng B, Kerfin A, Skjoedt MO, Garred P, Rosbjerg A. Transient Binding Dynamics of Complement System Pattern Recognition Molecules on Pathogens. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:1493-1503. [PMID: 38488502 DOI: 10.4049/jimmunol.2300768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/26/2024] [Indexed: 04/17/2024]
Abstract
Previous studies of pattern recognition molecules (PRMs) of the complement system have revealed difficulties in observing binding on pathogens such as Aspergillus fumigatus and Escherichia coli, despite complement deposition indicative of classical and lectin pathway activation. Thus, we investigated the binding dynamics of PRMs of the complement system, specifically C1q of the classical pathway and mannose-binding lectin (MBL) of the lectin pathway. We observed consistently increasing deposition of essential complement components such as C4b, C3b, and the terminal complement complex on A. fumigatus and E. coli. However, C1q and MBL binding to the surface rapidly declined during incubation after just 2-4 min in 10% plasma. The detachment of C1q and MBL can be linked to complement cascade activation, as the PRMs remain bound in the absence of plasma. The dissociation and the fate of C1q and MBL seem to have different mechanistic functions. Notably, C1q dynamics were associated with local C1 complex activation. When C1s was inhibited in plasma, C1q binding not only remained high but further increased over time. In contrast, MBL binding was inversely correlated with total and early complement activation due to MBL binding being partially retained by complement inhibition. Results indicate that detached MBL might be able to functionally rebind to A. fumigatus. In conclusion, these results reveal a (to our knowledge) novel "hit-and-run" complement-dependent PRM dynamic mechanism on pathogens. These dynamics may have profound implications for host defense and may help increase the functionality and longevity of complement-dependent PRMs in circulation.
Collapse
Affiliation(s)
- Maximilian Peter Götz
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Immunology and Infectious Diseases, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Institute for Systemic Inflammation Research, Medicine Section, University of Lübeck, Lübeck, Germany
| | - Mario Alejandro Duque Villegas
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Infection Immunology, Research Center Borstel, Borstel, Germany
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany
| | - Beatrice Fageräng
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Immunology, University of Oslo, Oslo University Hospital, Oslo, Norway
| | - Aileen Kerfin
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Institute for Systemic Inflammation Research, Medicine Section, University of Lübeck, Lübeck, Germany
| | - Mikkel-Ole Skjoedt
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter Garred
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anne Rosbjerg
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
2
|
Mao Z, Zhang H, Cai W, Yang Y, Zhang X, Jiang F, Li G. NhaA facilitates the maintenance of bacterial envelope integrity and the evasion of complement attack contributing to extraintestinal pathogenic Escherichia coli virulence. Infect Immun 2023; 91:e0003923. [PMID: 37815368 PMCID: PMC10652942 DOI: 10.1128/iai.00039-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 09/01/2023] [Indexed: 10/11/2023] Open
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) is responsible for severe bloodstream infections in humans and animals. However, the mechanisms underlying ExPEC's serum resistance remain incompletely understood. Through the transposon-directed insertion-site sequencing approach, our previous study identified nhaA, the gene encoding a Na+/H+ antiporter, as a crucial factor for infection in vivo. In this study, we investigated the role of NhaA in ExPEC virulence utilizing both in vitro models and systemic infection models involving avian and mammalian animals. Genetic mutagenesis analysis revealed that nhaA deletion resulted in filamentous bacterial morphology and rendered the bacteria more susceptible to sodium dodecyl sulfate, suggesting the role of nhaA in maintaining cell envelope integrity. The nhaA mutant also displayed heightened sensitivity to complement-mediated killing compared to the wild-type strain, attributed to augmented deposition of complement components (C3b and C9). Remarkably, NhaA played a more crucial role in virulence compared to several well-known factors, including Iss, Prc, NlpI, and OmpA. Our findings revealed that NhaA significantly enhanced virulence across diverse human ExPEC prototype strains within B2 phylogroups, suggesting widespread involvement in virulence. Given its pivotal role, NhaA could serve as a potential drug target for tackling ExPEC infections.
Collapse
Affiliation(s)
- Zhao Mao
- Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Haobo Zhang
- National Animal Tuberculosis Reference Laboratory, Division of Zoonoses Surveillance, China Animal Health and Epidemiology Center, Qingdao, China
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Wentong Cai
- Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yan Yang
- Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xinyang Zhang
- Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Fengwei Jiang
- Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Ganwu Li
- Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| |
Collapse
|
3
|
Schanzenbacher J, Hendrika Kähler K, Mesler E, Kleingarn M, Marcel Karsten C, Leonard Seiler D. The role of C5a receptors in autoimmunity. Immunobiology 2023; 228:152413. [PMID: 37598588 DOI: 10.1016/j.imbio.2023.152413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/04/2023] [Accepted: 06/10/2023] [Indexed: 08/22/2023]
Abstract
The complement system is an essential component of the innate immune response and plays a vital role in host defense and inflammation. Dysregulation of the complement system, particularly involving the anaphylatoxin C5a and its receptors (C5aR1 and C5aR2), has been linked to several autoimmune diseases, indicating the potential for targeted therapies. C5aR1 and C5aR2 are seven-transmembrane receptors with distinct signaling mechanisms that play both partially overlapping and opposing roles in immunity. Both receptors are expressed on a broad spectrum of immune and non-immune cells and are involved in cellular functions and physiological processes during homeostasis and inflammation. Dysregulated C5a-mediated inflammation contributes to autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, epidermolysis bullosa acquisita, antiphospholipid syndrome, and others. Therefore, targeting C5a or its receptors may yield therapeutic innovations in these autoimmune diseases by reducing the recruitment and activation of immune cells that lead to tissue inflammation and injury, thereby exacerbating the autoimmune response. Clinical trials focused on the inhibition of C5 cleavage or the C5a/C5aR1-axis using small molecules or monoclonal antibodies hold promise for bringing novel treatments for autoimmune diseases into practice. However, given the heterogeneous nature of (systemic) autoimmune diseases, there are still several challenges, such as patient selection, optimal dosing, and treatment duration, that require further investigation and development to realize the full therapeutic potential of C5a receptor inhibition, ideally in the context of a personalized medicine approach. Here, we aim to provide a brief overview of the current knowledge on the function of C5a receptors, the involvement of C5a receptors in autoimmune disorders, the molecular mechanisms underlying C5a receptor-mediated autoimmunity, and the potential for targeted therapies to modulate their activity.
Collapse
Affiliation(s)
- Jovan Schanzenbacher
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Katja Hendrika Kähler
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Evelyn Mesler
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Marie Kleingarn
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | | | - Daniel Leonard Seiler
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany.
| |
Collapse
|
4
|
Pejchinovski I, Turkkan S, Pejchinovski M. Recent Advances of Proteomics in Management of Acute Kidney Injury. Diagnostics (Basel) 2023; 13:2648. [PMID: 37627907 PMCID: PMC10453063 DOI: 10.3390/diagnostics13162648] [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: 06/28/2023] [Revised: 07/31/2023] [Accepted: 08/03/2023] [Indexed: 08/27/2023] Open
Abstract
Acute Kidney Injury (AKI) is currently recognized as a life-threatening disease, leading to an exponential increase in morbidity and mortality worldwide. At present, AKI is characterized by a significant increase in serum creatinine (SCr) levels, typically followed by a sudden drop in glomerulus filtration rate (GFR). Changes in urine output are usually associated with the renal inability to excrete urea and other nitrogenous waste products, causing extracellular volume and electrolyte imbalances. Several molecular mechanisms were proposed to be affiliated with AKI development and progression, ultimately involving renal epithelium tubular cell-cycle arrest, inflammation, mitochondrial dysfunction, the inability to recover and regenerate proximal tubules, and impaired endothelial function. Diagnosis and prognosis using state-of-the-art clinical markers are often late and provide poor outcomes at disease onset. Inappropriate clinical assessment is a strong disease contributor, actively driving progression towards end stage renal disease (ESRD). Proteins, as the main functional and structural unit of the cell, provide the opportunity to monitor the disease on a molecular level. Changes in the proteomic profiles are pivotal for the expression of molecular pathways and disease pathogenesis. Introduction of highly-sensitive and innovative technology enabled the discovery of novel biomarkers for improved risk stratification, better and more cost-effective medical care for the ill patients and advanced personalized medicine. In line with those strategies, this review provides and discusses the latest findings of proteomic-based biomarkers and their prospective clinical application for AKI management.
Collapse
Affiliation(s)
- Ilinka Pejchinovski
- Department of Quality Assurance, Nikkiso Europe GmbH, 30885 Langenhagen, Germany; (I.P.); (S.T.)
| | - Sibel Turkkan
- Department of Quality Assurance, Nikkiso Europe GmbH, 30885 Langenhagen, Germany; (I.P.); (S.T.)
| | - Martin Pejchinovski
- Department of Analytical Instruments Group, Thermo Fisher Scientific, 82110 Germering, Germany
| |
Collapse
|
5
|
Sülzen H, Began J, Dhillon A, Kereïche S, Pompach P, Votrubova J, Zahedifard F, Šubrtova A, Šafner M, Hubalek M, Thompson M, Zoltner M, Zoll S. Cryo-EM structures of Trypanosoma brucei gambiense ISG65 with human complement C3 and C3b and their roles in alternative pathway restriction. Nat Commun 2023; 14:2403. [PMID: 37105991 PMCID: PMC10140031 DOI: 10.1038/s41467-023-37988-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
African Trypanosomes have developed elaborate mechanisms to escape the adaptive immune response, but little is known about complement evasion particularly at the early stage of infection. Here we show that ISG65 of the human-infective parasite Trypanosoma brucei gambiense is a receptor for human complement factor C3 and its activation fragments and that it takes over a role in selective inhibition of the alternative pathway C5 convertase and thus abrogation of the terminal pathway. No deposition of C4b, as part of the classical and lectin pathway convertases, was detected on trypanosomes. We present the cryo-electron microscopy (EM) structures of native C3 and C3b in complex with ISG65 which reveal a set of modes of complement interaction. Based on these findings, we propose a model for receptor-ligand interactions as they occur at the plasma membrane of blood-stage trypanosomes and may facilitate innate immune escape of the parasite.
Collapse
Affiliation(s)
- Hagen Sülzen
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
- Faculty of Science, Charles University, Albertov 6, 12800, Prague 2, Czech Republic
| | - Jakub Began
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
- Department of Immunobiology, University of Lausanne, Chemin des Boveresses 155, 1066, Epalinges, Switzerland
| | - Arun Dhillon
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
| | - Sami Kereïche
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
- First Faculty of Medicine, Charles University, Albertov 4, 12800, Prague, Czech Republic
| | - Petr Pompach
- Institute of Biotechnology of the Czech Academy of Sciences, 25250, Vestec, Czech Republic
| | - Jitka Votrubova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
| | - Farnaz Zahedifard
- Department of Parasitology, Faculty of Science, Charles University Prague, Biocev, 25250, Vestec, Czech Republic
| | - Adriana Šubrtova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
| | - Marie Šafner
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
| | - Martin Hubalek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
| | - Maaike Thompson
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic
- University of Antwerp, Antwerp, Belgium
- Agidens, Industrial Machinery Manufacturing, Zwijndrecht, Antwerp, Belgium
| | - Martin Zoltner
- Department of Parasitology, Faculty of Science, Charles University Prague, Biocev, 25250, Vestec, Czech Republic
| | - Sebastian Zoll
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo namesti 542/2, 16000, Prague, Czech Republic.
| |
Collapse
|
6
|
Tsiftsoglou SA, Gavriilaki E, Touloumenidou T, Koravou EE, Koutra M, Papayanni PG, Karali V, Papalexandri A, Varelas C, Chatzopoulou F, Chatzidimitriou M, Chatzidimitriou D, Veleni A, Rapti E, Kioumis I, Kaimakamis E, Bitzani M, Boumpas DT, Tsantes A, Sotiropoulos D, Papadopoulou A, Sakellari I, Kokoris S, Anagnostopoulos A. Targeted genotyping of COVID-19 patients reveals a signature of complement C3 and factor B coding SNPs associated with severe infection. Immunobiology 2023; 228:152351. [PMID: 36805858 PMCID: PMC9928680 DOI: 10.1016/j.imbio.2023.152351] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 01/19/2023] [Accepted: 02/11/2023] [Indexed: 02/17/2023]
Abstract
We have attempted to explore further the involvement of complement components in the host COVID-19 (Coronavirus disease-19) immune responses by targeted genotyping of COVID-19 adult patients and analysis for missense coding Single Nucleotide Polymorphisms (coding SNPs) of genes encoding Alternative pathway (AP) components. We have identified a small group of common coding SNPs in Survivors and Deceased individuals, present in either relatively similar frequencies (CFH and CFI SNPs) or with stark differences in their relative abundance (C3 and CFB SNPs). In addition, we have identified several sporadic, potentially protective, coding SNPs of C3, CFB, CFD, CFH, CFHR1 and CFI in Survivors. No coding SNPs were detected for CD46 and CD55. Our demographic analysis indicated that the C3 rs1047286 or rs2230199 coding SNPs were present in 60 % of all the Deceased patients (n = 25) (the rs2230199 in 67 % of all Deceased Males) and in 31 % of all the Survivors (n = 105, p = 0.012) (the rs2230199 in 25 % of all Survivor Males). When we analysed these two major study groups using the presence of the C3 rs1047286 or rs2230199 SNPs as potential biomarkers, we noticed the complete absence of the protective CFB rs12614 and rs641153 coding SNPs from Deceased Males compared to Females (p = 0.0023). We propose that in these individuals, C3 carrying the R102G and CFB lacking the R32W or the R32Q amino acid substitutions, may contribute to enhanced association dynamics of the C3bBb AP pre-convertase complex assembly, thus enabling the exploitation of the activation of the Complement Alternative pathway (AP) by SARS-CoV-2.
Collapse
Affiliation(s)
- Stefanos A Tsiftsoglou
- Laboratory of Pharmacology, Department of Pharmaceutical Sciences, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.
| | - Eleni Gavriilaki
- Hematology Department-BMT Unit, G. Papanicolaou Hospital, Exochi, Thessaloniki 57010, Greece.
| | - Tasoula Touloumenidou
- Hematology Department-BMT Unit, G. Papanicolaou Hospital, Exochi, Thessaloniki 57010, Greece
| | | | - Maria Koutra
- Hematology Department-BMT Unit, G. Papanicolaou Hospital, Exochi, Thessaloniki 57010, Greece
| | | | - Vassiliki Karali
- Rheumatology and Clinical Immunology Unit, University General Hospital "Attikon", Αthens, Greece
| | - Apostolia Papalexandri
- Hematology Department-BMT Unit, G. Papanicolaou Hospital, Exochi, Thessaloniki 57010, Greece
| | - Christos Varelas
- Hematology Department-BMT Unit, G. Papanicolaou Hospital, Exochi, Thessaloniki 57010, 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
| | - Evdoxia Rapti
- Laboratory of Hematology and Hospital Blood Transfusion Department, University General Hospital "Attikon", NKUA, Medical School, Athens, 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 T Boumpas
- Rheumatology and Clinical Immunology Unit, University General Hospital "Attikon", Αthens, Greece
| | - Argyris Tsantes
- Laboratory of Hematology and Hospital Blood Transfusion Department, University General Hospital "Attikon", NKUA, Medical School, Athens, Greece
| | - Damianos Sotiropoulos
- Hematology Department-BMT Unit, G. Papanicolaou Hospital, Exochi, Thessaloniki 57010, Greece
| | - Anastasia Papadopoulou
- Hematology Department-BMT Unit, G. Papanicolaou Hospital, Exochi, Thessaloniki 57010, Greece
| | - Ioanna Sakellari
- Hematology Department-BMT Unit, G. Papanicolaou Hospital, Exochi, Thessaloniki 57010, Greece
| | - Styliani Kokoris
- Laboratory of Hematology and Hospital Blood Transfusion Department, University General Hospital "Attikon", NKUA, Medical School, Athens, Greece
| | | |
Collapse
|
7
|
Hourcade DE, Mitchell LM. A Monoclonal Antibody That Provides a Model for C3 Nephritic Factors. Monoclon Antib Immunodiagn Immunother 2023; 42:9-14. [PMID: 36853837 PMCID: PMC9983123 DOI: 10.1089/mab.2022.0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 01/17/2023] [Indexed: 03/01/2023] Open
Abstract
Complement is a major innate defense system that protects the intravascular space from microbial invasion. Complement activation results in the assembly of C3 convertases, serine proteases that cleave complement protein C3, generating bioactive fragments C3a and C3b. The complement response is rapid and robust, largely due to a positive feedback regulatory loop mediated by alternative pathway (AP) C3 convertase. C3 nephritic factors (C3NEFs) are autoantibodies that stabilize AP convertase, resulting in uncontrolled C3 cleavage, which, in principle, can promote critical tissue injury similar to that seen in certain renal conditions. Investigations of C3NEFs are hampered by a challenging issue: each C3NEF is derived from a different donor source, and there is no method to compare one C3NEF to another. We have identified a widely available mouse anti-C3 mAb that, similar to many C3NEFs, can stabilize functional AP convertase in a form resistant to decay acceleration by multiple complement regulators. The antibody requires the presence of properdin to confer convertase stability, and hampers the activity of Salp20, a tic salivary protein that accelerates convertase dissociation by displacing properdin from the convertase complex. This mAb can serve as an urgently needed standard for the investigation of C3NEFs. This study also provides novel insights into the dynamics of AP convertase.
Collapse
Affiliation(s)
- Dennis E. Hourcade
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lynne M. Mitchell
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| |
Collapse
|
8
|
Rodríguez de Córdoba S. Genetic variability shapes the alternative pathway complement activity and predisposition to complement-related diseases. Immunol Rev 2023; 313:71-90. [PMID: 36089777 PMCID: PMC10086816 DOI: 10.1111/imr.13131] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The implementation of next-generation sequencing technologies has provided a sharp picture of the genetic variability in the components and regulators of the alternative pathway (AP) of the complement system and has revealed the association of many AP variants with different rare and common diseases. An important finding that has emerged from these analyses is that each of these complement-related diseases associate with genetic variants altering specific aspects of the activation and regulation of the AP. These genotype-phenotype correlations have provided valuable insights into their pathogenic mechanisms with important diagnostic and therapeutic implications. While genetic variants in coding regions and structural variants are reasonably well characterized and occasionally have been instrumental to uncover unknown features of the complement proteins, data about complement expressed quantitative trait loci are still very limited. A crucial task for future studies will be to identify these quantitative variations and to determine their impact in the overall activity of the AP. This is fundamental as it is now clear that the consequences of genetic variants in the AP are additive and that susceptibility or resistance to disease is the result of specific combinations of genetic variants in different complement components and regulators ("complotypes").
Collapse
|
9
|
Song G, Wang S, Barkestani MN, Mullan C, Fan M, Jiang B, Jiang Q, Li X, Jane-wit D. Membrane attack complexes, endothelial cell activation, and direct allorecognition. Front Immunol 2022; 13:1020889. [PMID: 36211400 PMCID: PMC9539657 DOI: 10.3389/fimmu.2022.1020889] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/07/2022] [Indexed: 11/18/2022] Open
Abstract
Endothelial cells (ECs) form a critical immune interface regulating both the activation and trafficking of alloreactive T cells. In the setting of solid organ transplantation, donor-derived ECs represent sites where alloreactive T cells encounter major and minor tissue-derived alloantigens. During this initial encounter, ECs may formatively modulate effector responses of these T cells through expression of inflammatory mediators. Direct allorecognition is a process whereby recipient T cells recognize alloantigen in the context of donor EC-derived HLA molecules. Direct alloresponses are strongly modulated by human ECs and are galvanized by EC-derived inflammatory mediators. Complement are immune proteins that mark damaged or foreign surfaces for immune cell activation. Following labeling by natural IgM during ischemia reperfusion injury (IRI) or IgG during antibody-mediated rejection (ABMR), the complement cascade is terminally activated in the vicinity of donor-derived ECs to locally generate the solid-phase inflammatory mediator, the membrane attack complex (MAC). Via upregulation of leukocyte adhesion molecules, costimulatory molecules, and cytokine trans-presentation, MAC strengthen EC:T cell direct alloresponses and qualitatively shape the alloimmune T cell response. These processes together promote T cell-mediated inflammation during solid organ transplant rejection. In this review we describe molecular pathways downstream of IgM- and IgG-mediated MAC assembly on ECs in the setting of IRI and ABMR of tissue allografts, respectively. We describe work demonstrating that MAC deposition on ECs generates 'signaling endosomes' that sequester and post-translationally enhance the stability of inflammatory signaling molecules to promote EC activation, a process potentiating EC-mediated direct allorecognition. Additionally, with consideration to first-in-human xenotransplantation procedures, we describe clinical therapeutics based on inhibition of the complement pathway. The complement cascade critically mediates EC activation and improved understanding of relevant effector pathways will uncover druggable targets to obviate dysregulated alloimmune T cell infiltration into tissue allografts.
Collapse
Affiliation(s)
- Guiyu Song
- Section of Cardiovascular Medicine, Dept of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Shaoxun Wang
- Section of Cardiovascular Medicine, Dept of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
- Department of Surgery, Yale University School of Medicine, New Haven, CT, United States
| | - Mahsa Nouri Barkestani
- Section of Cardiovascular Medicine, Dept of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Clancy Mullan
- Department of Surgery, Yale University School of Medicine, New Haven, CT, United States
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, United States
| | - Matthew Fan
- Section of Cardiovascular Medicine, Dept of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Bo Jiang
- Department of Surgery, Yale University School of Medicine, New Haven, CT, United States
- Department of Vascular Surgery, The First Hospital of China Medical University, Shenyang, China
| | - Quan Jiang
- Section of Cardiovascular Medicine, Dept of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Xue Li
- Section of Cardiovascular Medicine, Dept of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
- Department of Nephrology, The First Hospital of China Medical University, Shenyang, China
| | - Dan Jane-wit
- Section of Cardiovascular Medicine, Dept of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, United States
- Department of Cardiology, West Haven VA Medical Center, West Haven, CT, United States
| |
Collapse
|
10
|
Cramer DAT, Franc V, Caval T, Heck AJR. Charting the Proteoform Landscape of Serum Proteins in Individual Donors by High-Resolution Native Mass Spectrometry. Anal Chem 2022; 94:12732-12741. [PMID: 36074704 PMCID: PMC9494300 DOI: 10.1021/acs.analchem.2c02215] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Most proteins in serum are glycosylated, with several
annotated
as biomarkers and thus diagnostically important and of interest for
their role in disease. Most methods for analyzing serum glycoproteins
employ either glycan release or glycopeptide centric mass spectrometry-based
approaches, which provide excellent tools for analyzing known glycans
but neglect previously undefined or unknown glycosylation and/or other
co-occurring modifications. High-resolution native mass spectrometry
is a relatively new technique for the analysis of intact glycoproteins,
providing a “what you see is what you get” mass profile
of a protein, allowing the qualitative and quantitative observation
of all modifications present. So far, a disadvantage of this approach
has been that it centers mostly on just one specific serum glycoprotein
at the time. To address this issue, we introduce an ion-exchange chromatography-based
fractionation method capable of isolating and analyzing, in parallel,
over 20 serum (glyco)proteins, covering a mass range between 30 and
190 kDa, from 150 μL of serum. Although generating data in parallel
for all these 20 proteins, we focus the discussion on the very complex
proteoform profiles of four selected proteins, i.e., α-1-antitrypsin,
ceruloplasmin, hemopexin, and complement protein C3. Our analyses
provide an insight into the extensive proteoform landscape of serum
proteins in individual donors, caused by the occurrence of various N- and O-glycans, protein cysteinylation,
and co-occurring genetic variants. Moreover, native mass intact mass
profiling also provided an edge over alternative approaches revealing
the presence of apo- and holo-forms of ceruloplasmin and the endogenous
proteolytic processing in plasma of among others complement protein
C3. We also applied our approach to a small cohort of serum samples
from healthy and diseased individuals. In these, we qualitatively
and quantitatively monitored the changes in proteoform profiles of
ceruloplasmin and revealed a substantial increase in fucosylation
and glycan occupancy in patients with late-stage hepatocellular carcinoma
and pancreatic cancer as compared to healthy donor samples.
Collapse
Affiliation(s)
- Dario A T Cramer
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Science, University of Utrecht, Padualaan 8, Utrecht 3584 CH, The Netherlands.,Netherlands Proteomics Centre, University of Utrecht, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | - Vojtech Franc
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Science, University of Utrecht, Padualaan 8, Utrecht 3584 CH, The Netherlands.,Netherlands Proteomics Centre, University of Utrecht, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | - Tomislav Caval
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Science, University of Utrecht, Padualaan 8, Utrecht 3584 CH, The Netherlands.,Netherlands Proteomics Centre, University of Utrecht, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Science, University of Utrecht, Padualaan 8, Utrecht 3584 CH, The Netherlands.,Netherlands Proteomics Centre, University of Utrecht, Padualaan 8, Utrecht 3584 CH, The Netherlands
| |
Collapse
|
11
|
Gerogianni A, Dimitrov JD, Zarantonello A, Poillerat V, Chonat S, Sandholm K, McAdam KE, Ekdahl KN, Mollnes TE, Mohlin C, Roumenina LT, Nilsson PH. Heme Interferes With Complement Factor I-Dependent Regulation by Enhancing Alternative Pathway Activation. Front Immunol 2022; 13:901876. [PMID: 35935964 PMCID: PMC9354932 DOI: 10.3389/fimmu.2022.901876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/23/2022] [Indexed: 11/13/2022] Open
Abstract
Hemolysis, as a result of disease or exposure to biomaterials, is characterized by excess amounts of cell-free heme intravascularly and consumption of the protective heme-scavenger proteins in plasma. The liberation of heme has been linked to the activation of inflammatory systems, including the complement system, through alternative pathway activation. Here, we investigated the impact of heme on the regulatory function of the complement system. Heme dose-dependently inhibited factor I-mediated degradation of soluble and surface-bound C3b, when incubated in plasma or buffer with complement regulatory proteins. Inhibition occurred with factor H and soluble complement receptor 1 as co-factors, and the mechanism was linked to the direct heme-interaction with factor I. The heme-scavenger protein hemopexin was the main contaminant in purified factor I preparations. This led us to identify that hemopexin formed a complex with factor I in normal human plasma. These complexes were significantly reduced during acute vasoocclusive pain crisis in patients with sickle cell disease, but the complexes were normalized at their baseline outpatient clinic visit. Hemopexin exposed a protective function of factor I activity in vitro, but only when it was present before the addition of heme. In conclusion, we present a mechanistic explanation of how heme promotes uncontrolled complement alternative pathway amplification by interfering with the regulatory capacity of factor I. Reduced levels of hemopexin and hemopexin-factor I complexes during an acute hemolytic crisis is a risk factor for heme-mediated factor I inhibition.
Collapse
Affiliation(s)
- Alexandra Gerogianni
- Linnaeus Centre for Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
- Department of Chemistry and Biomedicine, Linnaeus University, Kalmar, Sweden
| | - Jordan D. Dimitrov
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Paris, France
| | - Alessandra Zarantonello
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Paris, France
| | - Victoria Poillerat
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Paris, France
| | - Satheesh Chonat
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Atlanta, GA, United States
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Kerstin Sandholm
- Department of Chemistry and Biomedicine, Linnaeus University, Kalmar, Sweden
| | - Karin E. McAdam
- Department of Immunology, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Kristina N. Ekdahl
- Linnaeus Centre for Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
- Department of Chemistry and Biomedicine, Linnaeus University, Kalmar, Sweden
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Tom E. Mollnes
- Department of Immunology, Oslo University Hospital and University of Oslo, Oslo, Norway
- Centre of Molecular Inflammation Research, and Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
- Research Laboratory, Nordland Hospital, Bodo, Norway
| | - Camilla Mohlin
- Linnaeus Centre for Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
- Department of Chemistry and Biomedicine, Linnaeus University, Kalmar, Sweden
| | - Lubka T. Roumenina
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Paris, France
| | - Per H. Nilsson
- Linnaeus Centre for Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
- Department of Chemistry and Biomedicine, Linnaeus University, Kalmar, Sweden
- Department of Immunology, Oslo University Hospital and University of Oslo, Oslo, Norway
- *Correspondence: Per H. Nilsson,
| |
Collapse
|
12
|
Wang W, Sheng L, Chen Y, Li Z, Wu H, Ma J, Zhang D, Chen X, Zhang S. Total coumarin derivates from Hydrangea paniculata attenuate renal injuries in cationized-BSA induced membranous nephropathy by inhibiting complement activation and interleukin 10-mediated interstitial fibrosis. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 96:153886. [PMID: 35026512 DOI: 10.1016/j.phymed.2021.153886] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 11/21/2021] [Accepted: 12/05/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND Total coumarins extracted from Hydrangea. Paniculata, Sieb (HP) have showed renal protective effect in several experimental acute and chronic kidney diseases. PURPOSE The aim of current study is to evaluate renal protective effect of HP against cationized-BSA (c-BSA) induced experimental membranous nephritis (MN), and further investigate its underlying mechanisms. METHODS Rat MN model was established by intravenous injection of 5 mg c-BSA for consecutive 14 days, and after albuminuria confirmed, HP was orally administrated with 7.5, 15, 30 mg/kg for nine weeks. The renal function was measured and histopathological injuries were observed. RNA sequencing was used to analyze the altered signaling pathways in kidneys. Pharmacokinetics was performed to investigate the pharmacodynamics of major ingredients in HP and possible metabolites. Discover X platform helped to clarify the possible molecular mechanisms of major compound in HP. RESULTS HP administration could significantly improve the renal function, and ameliorate the dyslipidemia and histopathological injuries. mRNA sequencing demonstrated that HP had anti-inflammation and anti-fibrosis effects possible through down-regulating the complement activation and PI3K-AKT pathways. Pharmacokinetics demonstrated that skimmin and 7-hydoxycoumarin (7-HC) were major compound or metabolite in plasma after oral administration. Based on Discover X platform, we confirmed that skimmin and 7-HC inhibited the IL10 production by inflammatory macrophages through blocking PI3K-AKT and NFκB signaling pathways. Finally, we demonstrated that HP protected tubulointerstitium from complement attack by reducing the C3 self-production and auto-cleavage in tubular cells. CONCLUSIONS HP has a renal protective effect, and its drug development may provide one alternative strategy to treat immune-mediated nephropathy.
Collapse
Affiliation(s)
- Weida Wang
- State key laboratory of bioactive substances and functions of natural medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union medical college, Beijing, 100050, P.R. China
| | - Li Sheng
- State key laboratory of bioactive substances and functions of natural medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union medical college, Beijing, 100050, P.R. China
| | - Yuanyuan Chen
- State key laboratory of bioactive substances and functions of natural medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union medical college, Beijing, 100050, P.R. China
| | - Zhaojun Li
- State key laboratory of bioactive substances and functions of natural medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union medical college, Beijing, 100050, P.R. China
| | - Haijie Wu
- State key laboratory of bioactive substances and functions of natural medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union medical college, Beijing, 100050, P.R. China
| | - Jie Ma
- State key laboratory of bioactive substances and functions of natural medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union medical college, Beijing, 100050, P.R. China
| | - Dongming Zhang
- State key laboratory of bioactive substances and functions of natural medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union medical college, Beijing, 100050, P.R. China
| | - Xiaoguang Chen
- State key laboratory of bioactive substances and functions of natural medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union medical college, Beijing, 100050, P.R. China.
| | - Sen Zhang
- State key laboratory of bioactive substances and functions of natural medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union medical college, Beijing, 100050, P.R. China.
| |
Collapse
|
13
|
Jensen RK, Bajic G, Sen M, Springer TA, Vorup-Jensen T, Andersen GR. Complement Receptor 3 Forms a Compact High-Affinity Complex with iC3b. THE JOURNAL OF IMMUNOLOGY 2021; 206:3032-3042. [PMID: 34117107 DOI: 10.4049/jimmunol.2001208] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 04/13/2021] [Indexed: 11/19/2022]
Abstract
Complement receptor 3 (CR3, also known as Mac-1, integrin αMβ2, or CD11b/CD18) is expressed on a subset of myeloid and certain activated lymphoid cells. CR3 is essential for the phagocytosis of complement-opsonized particles such as pathogens and apoptotic or necrotic cells opsonized with the complement fragment iC3b and, to a lesser extent, C3dg. Although the interaction between the iC3b thioester domain and the ligand binding CR3 αM I-domain is structurally and functionally well characterized, the nature of additional CR3-iC3b interactions required for phagocytosis of complement-opsonized objects remains obscure. In this study, we analyzed the interaction between iC3b and the 150-kDa headpiece fragment of the CR3 ectodomain. Surface plasmon resonance experiments demonstrated a 30 nM affinity of the CR3 headpiece for iC3b compared with 515 nM for the iC3b thioester domain, whereas experiments monitoring binding of iC3b to CR3-expressing cells suggested an affinity of 50 nM for the CR3-iC3b interaction. Small angle x-ray scattering analysis revealed that iC3b adopts an extended but preferred conformation in solution. Upon interaction with CR3, iC3b rearranges to form a compact receptor-ligand complex. Overall, the data suggest that the iC3b-CR3 interaction is of high affinity and relies on minor contacts formed between CR3 and regions outside the iC3b thioester domain. Our results rationalize the more efficient phagocytosis elicited by iC3b than by C3dg and pave the way for the development of specific therapeutics for the treatment of inflammatory and neurodegenerative diseases that do not interfere with the recognition of noncomplement CR3 ligands.
Collapse
Affiliation(s)
- Rasmus K Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Goran Bajic
- Laboratory of Molecular Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA.,Department of Pediatrics, Harvard Medical School, Boston, MA.,Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Mehmet Sen
- Department of Biology and Biochemistry, University of Houston, Houston, TX
| | - Timothy A Springer
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA.,Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA; and
| | | | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark;
| |
Collapse
|
14
|
Kaufman SR, Yoganathan P, Small KW, Rusia D, Pachydaki SI, Conti SM, Wenz RE, Gersman MA, Shaya FS, Kustra R. Genetics and Age-Related Eye Disease Study Formulation Interaction in Neovascular Age-Related Macular Degeneration. JOURNAL OF VITREORETINAL DISEASES 2021; 5:46-52. [PMID: 37009583 PMCID: PMC9976046 DOI: 10.1177/2474126420941713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Purpose: This work aims to determine whether previously defined genotype risk groups interact with Age-Related Eye Disease Study formulation (AREDS-F) use in progression to neovascular age-related macular degeneration (nvAMD). Methods: We conducted a case-only study of 265 nvAMD patients. Patients were anonymously genotyped at the complement factor H and age-related maculopathy susceptibility 2 loci and segregated into genotype groups (GTGs) defined by specific combinations of risk alleles. Physicians, who were blind to patients’ GTGs, obtained patients’ AREDS-F use history. The facility performing genetic analysis was blind to the AREDS-F use history. We used logistic analysis to estimate the interaction coefficient between AREDS-F use and GTG 2 vs GTG 3 in a general-population model. Results: The odds ratio of numbers of patients reporting prior AREDS-F use to nonuse for GTG 2 vs GTG 3 was 4.18 ( P = .001). Logistic regression, correcting for nongenetic risk factors, gave an estimate of the β for interaction of AREDS-F with genotype of 1.57 ( P = .001). This estimates a corrected odds ratio associated with the effect of interaction of 4.81 between those in GTG 2 compared with those in GTG 3. Conclusions: Our data indicate an interaction between GTGs and AREDS-F use that is consistent in size and direction with previously published reports, which had found that using AREDS-F supplements significantly increases the risk of nvAMD for some users and significantly protects other users.
Collapse
Affiliation(s)
| | - Pradeepa Yoganathan
- Kresge Eye Institute, Wayne State University, Detroit, MI, USA
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Laurel Eye Clinic, Brookville, PA, USA
| | | | | | | | | | | | | | | | - Rafal Kustra
- Dana Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
15
|
Devalaraja-Narashimha K, Meagher K, Luo Y, Huang C, Kaplan T, Muthuswamy A, Halasz G, Casanova S, O'Brien J, Peyser Boiarsky R, McWhirter J, Gartner H, Bai Y, MacDonnell S, Liu C, Hu Y, Latuszek A, Wei Y, Prasad S, Huang T, Yancopoulos G, Murphy A, Olson W, Zambrowicz B, Macdonald L, Morton LG. Humanized C3 Mouse: A Novel Accelerated Model of C3 Glomerulopathy. J Am Soc Nephrol 2021; 32:99-114. [PMID: 33288630 PMCID: PMC7894673 DOI: 10.1681/asn.2020050698] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 10/16/2020] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND C3 glomerulopathy (C3G) is characterized by the alternative-pathway (AP) hyperactivation induced by nephritic factors or complement gene mutations. Mice deficient in complement factor H (CFH) are a classic C3G model, with kidney disease that requires several months to progress to renal failure. Novel C3G models can further contribute to understanding the mechanism behind this disease and developing therapeutic approaches. METHODS A novel, rapidly progressing, severe, murine model of C3G was developed by replacing the mouse C3 gene with the human C3 homolog using VelociGene technology. Functional, histologic, molecular, and pharmacologic assays characterize the presentation of renal disease and enable useful pharmacologic interventions in the humanized C3 (C3hu/hu) mice. RESULTS The C3hu/hu mice exhibit increased morbidity early in life and die by about 5-6 months of age. The C3hu/hu mice display elevated biomarkers of kidney dysfunction, glomerulosclerosis, C3/C5b-9 deposition, and reduced circulating C3 compared with wild-type mice. Administration of a C5-blocking mAb improved survival rate and offered functional and histopathologic benefits. Blockade of AP activation by anti-C3b or CFB mAbs also extended survival and preserved kidney function. CONCLUSIONS The C3hu/hu mice are a useful model for C3G because they share many pathologic features consistent with the human disease. The C3G phenotype in C3hu/hu mice may originate from a dysregulated interaction of human C3 protein with multiple mouse complement proteins, leading to unregulated C3 activation via AP. The accelerated disease course in C3hu/hu mice may further enable preclinical studies to assess and validate new therapeutics for C3G.
Collapse
|
16
|
Sena L, Oliveira-Toré CF, Skare T, de Messias-Reason IJ, Andrade FA. C3 Gene Functional Polymorphisms and C3 Serum Levels in Patients with Rheumatoid Arthritis. Immunol Invest 2020; 50:1027-1041. [PMID: 32787514 DOI: 10.1080/08820139.2020.1800726] [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] [Indexed: 01/25/2023]
Abstract
The complement system is a key component of the innate immunity that plays a significant role in the development and clinical presentation of Rheumatoid arthritis (RA). Complement protein C3 is a central molecule in the activation of complement with a significant role in the inflammatory processes of RA. Nevertheless, the impact of C3 gene polymorphisms in the development of RA is still unknown. The current study aimed to investigate the possible influence of C3 gene polymorphisms in the susceptibility and clinical expression of RA. Three C3 polymorphisms (rs2250656:A > G, intron 2; rs2230199:C > G [p.Arg102Gly], exon 3 and rs1047286:C > T [p.Pro314Leu], exon 9) were assessed by sequence-specific PCR in a total of 156 RA patients and 270 healthy controls from Southern Brazil. In addition, C3 levels were measured in 60 patients and 60 controls by immunoturbidimetry and clinical features were collected from medical records. The frequency of rs2230199 G allele and GG genotype was significantly higher in RA patients than controls (padj = 0.012 OR = 1.57 [1.11-2.31]; padj = 0.008, OR = 1.60 [1.35-2.33]) as well as the rs1047286 T and TT (padj = 0.010, OR = 1.67 [1.12-2.40]; padj = 0.001, OR = 1.83 [1.27-2.65] and the C3 AGT haplotype (padj = 0.0007 OR = 1.92 [1.32-2.80]). Moreover, C3 serum levels were higher in patients than controls (median: 169 mg/dl vs.155 mg/dl; padj = 0.022), as well as in RF seronegative compared with seropositive patients (172 mg/dl vs. 165 mg/dl; padj = 0.007). Our results suggest that the rs2230199 G (p.102Gly) and rs1047286 T (p.314Leu) alleles play a role in the pathophysiology of RA, possibly impacting complement activation by the alternative pathway.
Collapse
Affiliation(s)
- Leia Sena
- Laboratory of Molecular Immunopathology, Clinic Hospital, Federal University of Paraná, Curitiba, Brazil
| | - Camila F Oliveira-Toré
- Laboratory of Molecular Immunopathology, Clinic Hospital, Federal University of Paraná, Curitiba, Brazil
| | - Thelma Skare
- Rheumatology Unit, Evangelical Mackenzie Hospital, Curitiba, Brazil
| | | | - Fabiana Antunes Andrade
- Laboratory of Molecular Immunopathology, Clinic Hospital, Federal University of Paraná, Curitiba, Brazil
| |
Collapse
|
17
|
Zwarthoff SA, Berends ETM, Mol S, Ruyken M, Aerts PC, Józsi M, de Haas CJC, Rooijakkers SHM, Gorham RD. Functional Characterization of Alternative and Classical Pathway C3/C5 Convertase Activity and Inhibition Using Purified Models. Front Immunol 2018; 9:1691. [PMID: 30083158 PMCID: PMC6064732 DOI: 10.3389/fimmu.2018.01691] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/10/2018] [Indexed: 12/24/2022] Open
Abstract
Complement is essential for the protection against infections; however, dysregulation of complement activation can cause onset and progression of numerous inflammatory diseases. Convertase enzymes play a central role in complement activation and produce the key mediators of complement: C3 convertases cleave C3 to generate chemoattractant C3a and label target cells with C3b, which promotes phagocytosis; C5 convertases cleave C5 into chemoattractant C5a, and C5b, which drives formation of the membrane attack complex. Since convertases mediate nearly all complement effector functions, they are ideal targets for therapeutic complement inhibition. A unique feature of convertases is their covalent attachment to target cells, which effectively confines complement activation to the cell surface. However, surface localization precludes detailed analysis of convertase activation and inhibition. In our previous work, we developed a model system to form purified alternative pathway (AP) C5 convertases on C3b-coated beads and quantify C5 conversion via functional analysis of released C5a. Here, we developed a C3aR cell reporter system that enables functional discrimination between C3 and C5 convertases. By regulating the C3b density on the bead surface, we observe that high C3b densities are important for conversion of C5, but not C3, by AP convertases. Screening of well-characterized complement-binding molecules revealed that differential inhibition of AP C3 convertases (C3bBb) and C5 convertases [C3bBb(C3b)n] is possible. Although both convertases contain C3b, the C3b-binding molecules Efb-C/Ecb and FHR5 specifically inhibit C5 conversion. Furthermore, using a new classical pathway convertase model, we show that these C3b-binding proteins not only block AP C3/C5 convertases but also inhibit formation of a functional classical pathway C5 convertase under well-defined conditions. Our models enable functional characterization of purified convertase enzymes and provide a platform for the identification and development of specific convertase inhibitors for treatment of complement-mediated disorders.
Collapse
Affiliation(s)
- Seline A Zwarthoff
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Evelien T M Berends
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Sanne Mol
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Maartje Ruyken
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Piet C Aerts
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Mihály Józsi
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Carla J C de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Suzan H M Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Ronald D Gorham
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| |
Collapse
|
18
|
Jensen RK, Pihl R, Gadeberg TAF, Jensen JK, Andersen KR, Thiel S, Laursen NS, Andersen GR. A potent complement factor C3-specific nanobody inhibiting multiple functions in the alternative pathway of human and murine complement. J Biol Chem 2018; 293:6269-6281. [PMID: 29497000 PMCID: PMC5925797 DOI: 10.1074/jbc.ra117.001179] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/07/2018] [Indexed: 12/30/2022] Open
Abstract
The complement system is a complex, carefully regulated proteolytic cascade for which suppression of aberrant activation is of increasing clinical relevance, and inhibition of the complement alternative pathway is a subject of intense research. Here, we describe the nanobody hC3Nb1 that binds to multiple functional states of C3 with subnanomolar affinity. The nanobody causes a complete shutdown of alternative pathway activity in human and murine serum when present in concentrations comparable with that of C3, and hC3Nb1 is shown to prevent proconvertase assembly, as well as binding of the C3 substrate to C3 convertases. Our crystal structure of the C3b-hC3Nb1 complex and functional experiments demonstrate that proconvertase formation is blocked by steric hindrance between the nanobody and an Asn-linked glycan on complement factor B. In addition, hC3Nb1 is shown to prevent factor H binding to C3b, rationalizing its inhibition of factor I activity. Our results identify hC3Nb1 as a versatile, inexpensive, and powerful inhibitor of the alternative pathway in both human and murine in vitro model systems of complement activation.
Collapse
Affiliation(s)
| | - Rasmus Pihl
- Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark
| | | | - Jan K. Jensen
- From the Departments of Molecular Biology and Genetics and
| | | | - Steffen Thiel
- Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark
| | | | - Gregers R. Andersen
- From the Departments of Molecular Biology and Genetics and , To whom correspondence should be addressed:
Dept. of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark. Tel.:
45-5144-6530; Fax:
45-8619-6500; E-mail:
| |
Collapse
|
19
|
Roostaei T, Sadaghiani S, Mashhadi R, Falahatian M, Mohamadi E, Javadian N, Nazeri A, Doosti R, Naser Moghadasi A, Owji M, Hashemi Taheri AP, Shakouri Rad A, Azimi A, Voineskos AN, Nazeri A, Sahraian MA. Convergent effects of a functional C3 variant on brain atrophy, demyelination, and cognitive impairment in multiple sclerosis. Mult Scler 2018; 25:532-540. [PMID: 29485352 DOI: 10.1177/1352458518760715] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Complement system activation products are present in areas of neuroinflammation, demyelination, and neurodegeneration in brains of patients with multiple sclerosis (MS). C3 is a central element in the activation of complement cascades. A common coding variant in the C3 gene (rs2230199, C3R102G) affects C3 activity. OBJECTIVES To assess the effects of rs2230199 on MS severity using clinical, cognitive, and imaging measures. METHODS In total, 161 relapse-onset MS patients (Expanded Disability Status Scale (EDSS) ≤ 6) underwent physical assessments, cognitive tests (Paced Auditory Serial Addition Test (PASAT), Symbol Digit Modalities Test (SDMT), and California Verbal Learning Test (CVLT)), and magnetic resonance imaging (MRI). Lesion volumes were quantified semi-automatically. Voxel-wise analyses were performed to assess the effects of rs2230199 genotype on gray matter (GM) atrophy ( n = 155), white matter (WM) fractional anisotropy (FA; n = 105), and WM magnetization transfer ratio (MTR; n = 90). RESULTS While rs2230199 minor-allele dosage (C3-102G) showed no significant effect on EDSS and Multiple Sclerosis Functional Composite (MSFC), it was associated with worse cognitive performance ( p = 0.02), lower brain parenchymal fraction ( p = 0.003), and higher lesion burden ( p = 0.02). Moreover, voxel-wise analyses showed lower GM volume in subcortical structures and insula, and lower FA and MTR in several WM areas with higher copies of rs2230199 minor allele. CONCLUSION C3-rs2230199 affects white and GM damage as well as cognitive impairment in MS patients. Our findings support a causal role for complement system activity in the pathophysiology of MS.
Collapse
Affiliation(s)
- Tina Roostaei
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran/Interdisciplinary Neuroscience Research Program, Tehran University of Medical Sciences, Tehran, Iran/Kimel Family Translational Imaging-Genetics Laboratory, Research Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada/Department of Psychiatry, University of Toronto, Toronto, ON, Canada/Center for Translational and Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Shokufeh Sadaghiani
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran/Interdisciplinary Neuroscience Research Program, Tehran University of Medical Sciences, Tehran, Iran
| | - Rahil Mashhadi
- Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Masih Falahatian
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran/School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Esmaeil Mohamadi
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran
| | - Nina Javadian
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran
| | - Aria Nazeri
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran/Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Rozita Doosti
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran
| | - Abdorreza Naser Moghadasi
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran/Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahsa Owji
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran
| | | | - Ali Shakouri Rad
- Department of Radiology, Tehran University of Medical Sciences, Tehran, Iran
| | - Amirreza Azimi
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran/Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Aristotle N Voineskos
- Kimel Family Translational Imaging-Genetics Laboratory, Research Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada/Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Arash Nazeri
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran/Interdisciplinary Neuroscience Research Program, Tehran University of Medical Sciences, Tehran, Iran/Kimel Family Translational Imaging-Genetics Laboratory, Research Imaging Centre, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Mohammad Ali Sahraian
- Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences and Sina Hospital, Tehran, Iran/Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
20
|
Łukawska E, Polcyn-Adamczak M, Niemir ZI. The role of the alternative pathway of complement activation in glomerular diseases. Clin Exp Med 2018; 18:297-318. [DOI: 10.1007/s10238-018-0491-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 02/12/2018] [Indexed: 01/20/2023]
|
21
|
CFH and ARMS2 genetic risk determines progression to neovascular age-related macular degeneration after antioxidant and zinc supplementation. Proc Natl Acad Sci U S A 2018; 115:E696-E704. [PMID: 29311295 PMCID: PMC5789949 DOI: 10.1073/pnas.1718059115] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of severe vision loss in the elderly and has major economic and quality-of-life impact. Prophylactic high-dose zinc and antioxidant supplements treatments are typically recommended with the assumption of homogeneously distributed benefit and risk of developing neovascular AMD. We show that individual variation at complement factor H and age-related maculopathy susceptibility 2, genes which predispose to AMD, also determines the effectiveness of nutritional prophylaxis. Some individuals paradoxically experience worsening disease with treatment, while others experience greater than average benefit. These divergent responses are difficult to identify when treatment effects have long latency. Understanding individual variations in prophylactic treatment response should inform future research and optimize health outcomes. We evaluated the influence of an antioxidant and zinc nutritional supplement [the Age-Related Eye Disease Study (AREDS) formulation] on delaying or preventing progression to neovascular AMD (NV) in persons with age-related macular degeneration (AMD). AREDS subjects (n = 802) with category 3 or 4 AMD at baseline who had been treated with placebo or the AREDS formulation were evaluated for differences in the risk of progression to NV as a function of complement factor H (CFH) and age-related maculopathy susceptibility 2 (ARMS2) genotype groups. We used published genetic grouping: a two-SNP haplotype risk-calling algorithm to assess CFH, and either the single SNP rs10490924 or 372_815del443ins54 to mark ARMS2 risk. Progression risk was determined using the Cox proportional hazard model. Genetics–treatment interaction on NV risk was assessed using a multiiterative bootstrap validation analysis. We identified strong interaction of genetics with AREDS formulation treatment on the development of NV. Individuals with high CFH and no ARMS2 risk alleles and taking the AREDS formulation had increased progression to NV compared with placebo. Those with low CFH risk and high ARMS2 risk had decreased progression risk. Analysis of CFH and ARMS2 genotype groups from a validation dataset reinforces this conclusion. Bootstrapping analysis confirms the presence of a genetics–treatment interaction and suggests that individual treatment response to the AREDS formulation is largely determined by genetics. The AREDS formulation modifies the risk of progression to NV based on individual genetics. Its use should be based on patient-specific genotype.
Collapse
|
22
|
de Jorge EG, Yebenes H, Serna M, Tortajada A, Llorca O, de Córdoba SR. How novel structures inform understanding of complement function. Semin Immunopathol 2017; 40:3-14. [PMID: 28808775 DOI: 10.1007/s00281-017-0643-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/03/2017] [Indexed: 11/30/2022]
Abstract
During the last decade, the complement field has experienced outstanding advancements in the mechanistic understanding of how complement activators are recognized, what C3 activation means, how protein complexes like the C3 convertases and the membrane attack complex are assembled, and how positive and negative complement regulators perform their function. All of this has been made possible mostly because of the contributions of structural biology to the study of the complement components. The wealth of novel structural data has frequently provided support to previously held knowledge, but often has added alternative and unexpected insights into complement function. Here, we will review some of these findings focusing in the alternative and terminal complement pathways.
Collapse
Affiliation(s)
- Elena Goicoechea de Jorge
- Department of Microbiology I (Immunology), Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Hugo Yebenes
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Marina Serna
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Agustín Tortajada
- Department of Microbiology I (Immunology), Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Oscar Llorca
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain.,Structural Biology Programme, CNIO, C/ Melchor Fernández Almagro 3, 28029, Madrid, Spain
| | - Santiago Rodríguez de Córdoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain. .,Ciber de Enfermedades Raras, Madrid, Spain.
| |
Collapse
|
23
|
Schatz-Jakobsen JA, Pedersen DV, Andersen GR. Structural insight into proteolytic activation and regulation of the complement system. Immunol Rev 2017; 274:59-73. [PMID: 27782336 DOI: 10.1111/imr.12465] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complement system is a highly complex and carefully regulated proteolytic cascade activated through three different pathways depending on the activator recognized. The structural knowledge regarding the intricate proteolytic enzymes that activate and control complement has increased dramatically over the last decade. This development has been pivotal for understanding how mutations within complement proteins might contribute to pathogenesis and has spurred new strategies for development of complement therapeutics. Here we describe and discuss the complement system from a structural perspective and integrate the most recent findings obtained by crystallography, small-angle X-ray scattering, and electron microscopy. In particular, we focus on the proteolytic enzymes governing activation and their products carrying the biological effector functions. Additionally, we present the structural basis for some of the best known complement inhibitors. The large number of accumulated molecular structures enables us to visualize the relative size, position, and overall orientation of many of the most interesting complement proteins and assembled complexes on activator surfaces and in membranes.
Collapse
Affiliation(s)
| | - Dennis V Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
| |
Collapse
|
24
|
Michielsen LA, van Zuilen AD, Muskens IS, Verhaar MC, Otten HG. Complement Polymorphisms in Kidney Transplantation: Critical in Graft Rejection? Am J Transplant 2017; 17:2000-2007. [PMID: 28097805 DOI: 10.1111/ajt.14199] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 12/21/2016] [Accepted: 01/04/2017] [Indexed: 01/25/2023]
Abstract
The complement system, as part of the innate immune system, plays an important role in renal transplantation. Complement is involved in the protection against foreign organisms and clearance of apoptotic cells but can also cause injury to the renal allograft, for instance, via antibody binding or in ischemia-reperfusion injury. Numerous polymorphisms in complement factors have been identified thus far; some of them result in different functionalities or alter complement levels. In this review, we provide an overview of the literature on the role of complement polymorphisms in renal transplantation. Furthermore, we discuss functional complement polymorphisms that have not yet been investigated in kidney transplantation. By investigating multiple polymorphisms both in donor and recipient at the same time, a complotype can be constructed. Because the combination of multiple polymorphisms is likely to have a greater impact than a single one, this could provide valuable prognostic information.
Collapse
Affiliation(s)
- L A Michielsen
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, the Netherlands
| | - A D van Zuilen
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, the Netherlands
| | - I S Muskens
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, the Netherlands
| | - M C Verhaar
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, the Netherlands
| | - H G Otten
- Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, the Netherlands
| |
Collapse
|
25
|
López-Perrote A, Harrison RES, Subías M, Alcorlo M, Rodríguez de Córdoba S, Morikis D, Llorca O. Ionic tethering contributes to the conformational stability and function of complement C3b. Mol Immunol 2017; 85:137-147. [PMID: 28254726 DOI: 10.1016/j.molimm.2016.12.015] [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: 09/23/2016] [Revised: 12/13/2016] [Accepted: 12/15/2016] [Indexed: 11/28/2022]
Abstract
C3b, the central component of the alternative pathway (AP) of the complement system, coexists as a mixture of conformations in solution. These conformational changes can affect interactions with other proteins and complement regulators. Here we combine a computational model for electrostatic interactions within C3b with molecular imaging to study the conformation of C3b. The computational analysis shows that the TED domain in C3b is tethered ionically to the macroglobulin (MG) ring. Monovalent counterion concentration affects the magnitude of electrostatic forces anchoring the TED domain to the rest of the C3b molecule in a thermodynamic model. This is confirmed by observing NaCl concentration dependent conformational changes using single molecule electron microscopy (EM). We show that the displacement of the TED domain is compatible with C3b binding to Factor B (FB), suggesting that the regulation of the C3bBb convertase could be affected by conditions that promote movement in the TED domain. Our molecular model also predicts mutations that could alter the positioning of the TED domain, including the common R102G polymorphism, a risk variant for developing age-related macular degeneration. The common C3b isoform, C3bS, and the risk isoform, C3bF, show distinct energetic barriers to displacement in the TED that are related to a network of electrostatic interactions at the interface of the TED and MG-ring domains of C3b. These computational predictions agree with experimental evidence that shows differences in conformation observed in C3b isoforms purified from homozygous donors. Altogether, we reveal an ionic, reversible attachment of the TED domain to the MG ring that may influence complement regulation in some mutations and polymorphisms of C3b.
Collapse
Affiliation(s)
- Andrés López-Perrote
- Centro de Investigaciones Biológicas, Spanish National Research Council (CSIC), Madrid, Spain
| | - Reed E S Harrison
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Marta Subías
- Centro de Investigaciones Biológicas, Spanish National Research Council (CSIC), Madrid, Spain; Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain
| | - Martín Alcorlo
- Centro de Investigaciones Biológicas, Spanish National Research Council (CSIC), Madrid, Spain
| | - Santiago Rodríguez de Córdoba
- Centro de Investigaciones Biológicas, Spanish National Research Council (CSIC), Madrid, Spain; Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain.
| | - Dimitrios Morikis
- Department of Bioengineering, University of California, Riverside, CA 92521, USA.
| | - Oscar Llorca
- Centro de Investigaciones Biológicas, Spanish National Research Council (CSIC), Madrid, Spain.
| |
Collapse
|
26
|
Papanastasiou M, Koutsogiannaki S, Sarigiannis Y, Geisbrecht BV, Ricklin D, Lambris JD. Structural Implications for the Formation and Function of the Complement Effector Protein iC3b. THE JOURNAL OF IMMUNOLOGY 2017; 198:3326-3335. [PMID: 28258193 DOI: 10.4049/jimmunol.1601864] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/10/2017] [Indexed: 01/17/2023]
Abstract
Complement-mediated opsonization, phagocytosis, and immune stimulation are critical processes in host defense and homeostasis, with the complement activation fragment iC3b playing a key effector role. To date, however, there is no high-resolution structure of iC3b, and some aspects of its structure-activity profile remain controversial. Here, we employed hydrogen-deuterium exchange mass spectrometry to describe the structure and dynamics of iC3b at a peptide resolution level in direct comparison with its parent protein C3b. In our hydrogen-deuterium exchange mass spectrometry study, 264 peptides were analyzed for their deuterium content, providing almost complete sequence coverage for this 173-kDa protein. Several peptides in iC3b showed significantly higher deuterium uptake when compared with C3b, revealing more dynamic, solvent-exposed regions. Most of them resided in the CUB domain, which contains the heptadecapeptide C3f that is liberated during the conversion of C3b to iC3b. Our data suggest a highly disordered CUB, which has acquired a state similar to that of intrinsically disordered proteins, resulting in a predominant form of iC3b that features high structural flexibility. The structure was further validated using an anti-iC3b mAb that was shown to target an epitope in the CUB region. The information obtained in this work allows us to elucidate determinants of iC3b specificity and activity and provide functional insights into the protein's recognition pattern with respect to regulators and receptors of the complement system.
Collapse
Affiliation(s)
- Malvina Papanastasiou
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - Sophia Koutsogiannaki
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - Yiannis Sarigiannis
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - Brian V Geisbrecht
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506
| | - Daniel Ricklin
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| |
Collapse
|
27
|
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.
Collapse
|
28
|
Luz PR, Miyazaki MI, Chiminacio Neto N, Padeski MC, Barros ACM, Boldt ABW, Messias-Reason IJ. Genetically Determined MBL Deficiency Is Associated with Protection against Chronic Cardiomyopathy in Chagas Disease. PLoS Negl Trop Dis 2016; 10:e0004257. [PMID: 26745156 PMCID: PMC4706301 DOI: 10.1371/journal.pntd.0004257] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 11/02/2015] [Indexed: 02/06/2023] Open
Abstract
Chagas disease (CD) is caused by Trypanosoma cruzi, whose sugar moieties are recognized by mannan binding lectin (MBL), a soluble pattern-recognition molecule that activates the lectin pathway of complement. MBL levels and protein activity are affected by polymorphisms in the MBL2 gene. We sequenced the MBL2 promoter and exon 1 in 196 chronic CD patients and 202 controls. The MBL2*C allele, which causes MBL deficiency, was associated with protection against CD (P = 0.007, OR = 0.32). Compared with controls, genotypes with this allele were completely absent in patients with the cardiac form of the disease (P = 0.003). Furthermore, cardiac patients with genotypes causing MBL deficiency presented less heart damage (P = 0.003, OR = 0.23), compared with cardiac patients having the XA haplotype causing low MBL levels, but fully capable of activating complement (P = 0.005, OR = 7.07). Among the patients, those with alleles causing MBL deficiency presented lower levels of cytokines and chemokines possibly implicated in symptom development (IL9, p = 0.013; PDGFB, p = 0.036 and RANTES, p = 0.031). These findings suggest a protective effect of genetically determined MBL deficiency against the development and progression of chronic CD cardiomyopathy. Chagas disease is considered an important neglected tropical disease, affecting approximately ten million people in Latin America. Although most infected individuals remain asymptomatic, one third of patients develop a chronic heart disease, with progressive inflammation, increase of myocardium, arrhythmia, cardiac insufficiency and heart failure. To date, there is no available marker to indicate the progression neither to determinate the severity of heart damage. Mannan binding lectin (MBL) is an important protein of the immune system able to recognize specific regions on the microorganism surfaces (including Trypanosoma cruzi, the causal agent of Chagas disease) which activate the complement system, a crucial mechanism of the effector immunity. MBL levels and protein activity are affected by genetic differences, named polymorphisms, in the MBL2 gene. This is the first Brazilian study with MBL2 polymorphisms in chronic Chagas disease. We sequenced two regions of MBL2 gene in 196 patients and 202 controls. We found that a polymorphism associated with deficient complement activation protects against Chagas disease and patients with deficiency-associated genotypes presented less echocardiographic alterations. Among the patients, those with alleles causing MBL deficiency presented lower levels of cytokines and chemokines possibly implicated in symptom development (IL9, p = 0.013; PDGFB, p = 0.036 and RANTES, p = 0.031). These findings lead us to suggest that genetically determined MBL deficiency plays a protective role against the development and progression of chronic Chagas disease.
Collapse
Affiliation(s)
- Paola Rosa Luz
- Laboratório de Imunopatologia Molecular–Departamento de Patologia Médica, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brasil
| | - Márcia I. Miyazaki
- Ambulatório de Atenção ao Paciente Chagásico—Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brasil
| | - Nelson Chiminacio Neto
- Serviço de Ecocardiografia—Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brasil
| | - Marcela C. Padeski
- Laboratório de Imunopatologia Molecular–Departamento de Patologia Médica, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brasil
| | - Ana Cláudia M. Barros
- Laboratório de Imunopatologia Molecular–Departamento de Patologia Médica, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brasil
| | - Angelica B. W. Boldt
- Laboratório de Imunopatologia Molecular–Departamento de Patologia Médica, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brasil
- Laboratório de Genética Molecular Humana–Departamento de Genética, Universidade Federal do Paraná, Curitiba, Brasil
| | - Iara J. Messias-Reason
- Laboratório de Imunopatologia Molecular–Departamento de Patologia Médica, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brasil
- * E-mail:
| |
Collapse
|
29
|
Berends ETM, Gorham RD, Ruyken M, Soppe JA, Orhan H, Aerts PC, de Haas CJC, Gros P, Rooijakkers SHM. Molecular insights into the surface-specific arrangement of complement C5 convertase enzymes. BMC Biol 2015; 13:93. [PMID: 26552476 PMCID: PMC4638095 DOI: 10.1186/s12915-015-0203-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 10/21/2015] [Indexed: 01/07/2023] Open
Abstract
Background Complement is a large protein network in plasma that is crucial for human immune defenses and a major cause of aberrant inflammatory reactions. The C5 convertase is a multi-molecular protease complex that catalyses the cleavage of native C5 into its biologically important products. So far, it has been difficult to study the exact molecular arrangement of C5 convertases, because their non-catalytic subunits (C3b) are covalently linked to biological surfaces through a reactive thioester. Through development of a highly purified model system for C5 convertases, we here aim to provide insights into the surface-specific nature of these important protease complexes. Results Alternative pathway (AP) C5 convertases were generated on small streptavidin beads that were coated with purified C3b molecules. Site-specific biotinylation of C3b via the thioester allowed binding of C3b in the natural orientation on the surface. In the presence of factor B and factor D, these C3b beads could effectively convert C5. Conversion rates of surface-bound C3b were more than 100-fold higher than fluid-phase C3b, confirming the requirement of a surface. We determine that high surface densities of C3b, and its attachment via the thioester, are essential for C5 convertase formation. Combining our results with molecular modeling explains how high C3b densities may facilitate intermolecular interactions that only occur on target surfaces. Finally, we define two interfaces on C5 important for its recognition by surface-bound C5 convertases. Conclusions We establish a highly purified model that mimics the natural arrangement of C5 convertases on a surface. The developed model and molecular insights are essential to understand the molecular basis of deregulated complement activity in human disease and will facilitate future design of therapeutic interventions against these critical enzymes in inflammation. Electronic supplementary material The online version of this article (doi:10.1186/s12915-015-0203-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Evelien T M Berends
- Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Ronald D Gorham
- Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Maartje Ruyken
- Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Jasper A Soppe
- Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Hatice Orhan
- Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Piet C Aerts
- Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Carla J C de Haas
- Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Piet Gros
- Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.,Department of Chemistry, Faculty of Science, Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Suzan H M Rooijakkers
- Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
| |
Collapse
|
30
|
Chauvet S, Roumenina LT, Bruneau S, Marinozzi MC, Rybkine T, Schramm EC, Java A, Atkinson JP, Aldigier JC, Bridoux F, Touchard G, Fremeaux-Bacchi V. A Familial C3GN Secondary to Defective C3 Regulation by Complement Receptor 1 and Complement Factor H. J Am Soc Nephrol 2015; 27:1665-77. [PMID: 26471127 DOI: 10.1681/asn.2015040348] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 08/24/2015] [Indexed: 01/29/2023] Open
Abstract
C3 glomerulopathy is a recently described form of CKD. C3GN is a subtype of C3 glomerulopathy characterized by predominant C3 deposits in the glomeruli and is commonly the result of acquired or genetic abnormalities in the alternative pathway (AP) of the complement system. We identified and characterized the first mutation of the C3 gene (p. I734T) in two related individuals diagnosed with C3GN. Immunofluorescence and electron microscopy studies showed C3 deposits in the subendothelial space, associated with unusual deposits located near the complement receptor 1 (CR1)-expressing podocytes. In vitro, this C3 mutation exhibited decreased binding to CR1, resulting in less CR1-dependent cleavage of C3b by factor 1. Both patients had normal plasma C3 levels, and the mutant C3 interacted with factor B comparably to wild-type (WT) C3 to form a C3 convertase. Binding of mutant C3 to factor H was normal, but mutant C3 was less efficiently cleaved by factor I in the presence of factor H, leading to enhanced C3 fragment deposition on glomerular cells. In conclusion, our results reveal that a CR1 functional deficiency is a mechanism of intraglomerular AP dysregulation and could influence the localization of the glomerular C3 deposits.
Collapse
Affiliation(s)
- Sophie Chauvet
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S1138, Complément et Maladies, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (UPMC-Paris-6), Paris, France;
| | - Lubka T Roumenina
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S1138, Complément et Maladies, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (UPMC-Paris-6), Paris, France
| | - Sarah Bruneau
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S1064, Institut de Transplantation Urologie-Nephrologie, Centre Hospitalier Universitaire de Nantes, Université de Nantes, Nantes, France
| | - Maria Chiara Marinozzi
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S1138, Complément et Maladies, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (UPMC-Paris-6), Paris, France; Assistance Publique-Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital européen Georges Pompidou, Paris, France
| | - Tania Rybkine
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S1138, Complément et Maladies, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (UPMC-Paris-6), Paris, France
| | - Elizabeth C Schramm
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, Saint Louis, Missouri
| | - Anuja Java
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, Saint Louis, Missouri
| | - John P Atkinson
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, Saint Louis, Missouri
| | | | | | - Guy Touchard
- Service de Nephrologie, and Service d'Anatomo-Pathologie et Pathologie ultrastructurale, Hôpital de Poitiers, France
| | - Veronique Fremeaux-Bacchi
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S1138, Complément et Maladies, Centre de Recherche des Cordeliers, Paris, France; Assistance Publique-Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital européen Georges Pompidou, Paris, France
| |
Collapse
|
31
|
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.
Collapse
|
32
|
Alcorlo M, López-Perrote A, Delgado S, Yébenes H, Subías M, Rodríguez-Gallego C, Rodríguez de Córdoba S, Llorca O. Structural insights on complement activation. FEBS J 2015; 282:3883-91. [PMID: 26250513 DOI: 10.1111/febs.13399] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/06/2015] [Accepted: 08/04/2015] [Indexed: 11/29/2022]
Abstract
The proteolytic cleavage of C3 to generate C3b is the central and most important step in the activation of complement, a major component of innate immunity. The comparison of the crystal structures of C3 and C3b illustrates large conformational changes during the transition from C3 to C3b. Exposure of a reactive thio-ester group allows C3b to bind covalently to surfaces such as pathogens or apoptotic cellular debris. The displacement of the thio-ester-containing domain (TED) exposes hidden surfaces that mediate the interaction with complement factor B to assemble the C3-convertase of the alternative pathway (AP). In addition, the displacement of the TED and its interaction with the macroglobulin 1 (MG1) domain generates an extended surface in C3b where the complement regulators factor H (FH), decay accelerating factor (DAF), membrane cofactor protein (MCP) and complement receptor 1 (CR1) can bind, mediating accelerated decay of the AP C3-convertase and proteolytic inactivation of C3b. In the last few years, evidence has accumulated revealing that the structure of C3b in solution is significantly more flexible than anticipated. We review our current knowledge on C3b structural flexibility to propose a general model where the TED can display a collection of conformations around the MG ring, as well as a few specialized positions where the TED is held in one of several fixed locations. Importantly, this conformational heterogeneity in C3b impacts complement regulation by affecting the interaction with regulators.
Collapse
Affiliation(s)
- Martín Alcorlo
- Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Andrés López-Perrote
- Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Sandra Delgado
- BioGUNE, Unidad de Biología Estructural - Ed. 800, Derio, Bizkaia, Spain
| | - Hugo Yébenes
- Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Marta Subías
- Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - César Rodríguez-Gallego
- Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Santiago Rodríguez de Córdoba
- Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas, Madrid, Spain.,Centro Investigaciones Biológicas, Ciber de Enfermedades Raras, Madrid, Spain
| | - Oscar Llorca
- Centro de Investigaciones Biológicas (CIB), Consejo Superior de Investigaciones Científicas, Madrid, Spain
| |
Collapse
|
33
|
Merle NS, Church SE, Fremeaux-Bacchi V, Roumenina LT. Complement System Part I - Molecular Mechanisms of Activation and Regulation. Front Immunol 2015; 6:262. [PMID: 26082779 PMCID: PMC4451739 DOI: 10.3389/fimmu.2015.00262] [Citation(s) in RCA: 1011] [Impact Index Per Article: 112.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/11/2015] [Indexed: 12/12/2022] Open
Abstract
Complement is a complex innate immune surveillance system, playing a key role in defense against pathogens and in host homeostasis. The complement system is initiated by conformational changes in recognition molecular complexes upon sensing danger signals. The subsequent cascade of enzymatic reactions is tightly regulated to assure that complement is activated only at specific locations requiring defense against pathogens, thus avoiding host tissue damage. Here, we discuss the recent advances describing the molecular and structural basis of activation and regulation of the complement pathways and their implication on physiology and pathology. This article will review the mechanisms of activation of alternative, classical, and lectin pathways, the formation of C3 and C5 convertases, the action of anaphylatoxins, and the membrane-attack-complex. We will also discuss the importance of structure-function relationships using the example of atypical hemolytic uremic syndrome. Lastly, we will discuss the development and benefits of therapies using complement inhibitors.
Collapse
Affiliation(s)
- Nicolas S Merle
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France
| | - Sarah Elizabeth Church
- UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France ; UMR_S 1138, Cordeliers Research Center, Integrative Cancer Immunology Team, INSERM , Paris , France
| | - Veronique Fremeaux-Bacchi
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France ; Service d'Immunologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou , Paris , France
| | - Lubka T Roumenina
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France
| |
Collapse
|
34
|
Wright DW, Perkins SJ. SCT: a suite of programs for comparing atomistic models with small-angle scattering data. J Appl Crystallogr 2015; 48:953-961. [PMID: 26089768 PMCID: PMC4453981 DOI: 10.1107/s1600576715007062] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 04/08/2015] [Indexed: 12/31/2022] Open
Abstract
Small-angle X-ray and neutron scattering techniques characterize proteins in solution and complement high-resolution structural studies. They are of particular utility when large proteins cannot be crystallized or when the structure is altered by solution conditions. Atomistic models of the averaged structure can be generated through constrained modelling, a technique in which known domain or subunit structures are combined with linker models to produce candidate global conformations. By randomizing the configuration adopted by the different elements of the model, thousands of candidate structures are produced. Next, theoretical scattering curves are generated for each model for trial-and-error fits to the experimental data. From these, a small family of best-fit models is identified. In order to facilitate both the computation of theoretical scattering curves from atomistic models and their comparison with experiment, the SCT suite of tools was developed. SCT also includes programs that provide sequence-based estimates of protein volume (either incorporating hydration or not) and add a hydration layer to models for X-ray scattering modelling. The original SCT software, written in Fortran, resulted in the first atomistic scattering structures to be deposited in the Protein Data Bank, and 77 structures for antibodies, complement proteins and anionic oligosaccharides were determined between 1998 and 2014. For the first time, this software is publicly available, alongside an easier-to-use reimplementation of the same algorithms in Python. Both versions of SCT have been released as open-source software under the Apache 2 license and are available for download from https://github.com/dww100/sct.
Collapse
Affiliation(s)
- David W. Wright
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Stephen J. Perkins
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| |
Collapse
|
35
|
Mortensen S, Kidmose RT, Petersen SV, Szilágyi Á, Prohászka Z, Andersen GR. Structural Basis for the Function of Complement Component C4 within the Classical and Lectin Pathways of Complement. THE JOURNAL OF IMMUNOLOGY 2015; 194:5488-96. [PMID: 25911760 DOI: 10.4049/jimmunol.1500087] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/22/2015] [Indexed: 11/19/2022]
Abstract
Complement component C4 is a central protein in the classical and lectin pathways within the complement system. During activation of complement, its major fragment C4b becomes covalently attached to the surface of pathogens and altered self-tissue, where it acts as an opsonin marking the surface for removal. Moreover, C4b provides a platform for assembly of the proteolytically active convertases that mediate downstream complement activation by cleavage of C3 and C5. In this article, we present the crystal and solution structures of the 195-kDa C4b. Our results provide the molecular details of the rearrangement accompanying C4 cleavage and suggest intramolecular flexibility of C4b. The conformations of C4b and its paralogue C3b are shown to be remarkably conserved, suggesting that the convertases from the classical and alternative pathways are likely to share their overall architecture and mode of substrate recognition. We propose an overall molecular model for the classical pathway C5 convertase in complex with C5, suggesting that C3b increases the affinity for the substrate by inducing conformational changes in C4b rather than a direct interaction with C5. C4b-specific features revealed by our structural studies are probably involved in the assembly of the classical pathway C3/C5 convertases and C4b binding to regulators.
Collapse
Affiliation(s)
- Sofia Mortensen
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus, Denmark
| | - Rune T Kidmose
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus, Denmark
| | - Steen V Petersen
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark; and
| | - Ágnes Szilágyi
- 3rd Department of Internal Medicine, Semmelweis University, Budapest 1125, Hungary
| | - Zoltan Prohászka
- 3rd Department of Internal Medicine, Semmelweis University, Budapest 1125, Hungary
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus, Denmark;
| |
Collapse
|
36
|
Martínez-Barricarte R, Heurich M, López-Perrote A, Tortajada A, Pinto S, López-Trascasa M, Sánchez-Corral P, Morgan BP, Llorca O, Harris CL, Rodríguez de Córdoba S. The molecular and structural bases for the association of complement C3 mutations with atypical hemolytic uremic syndrome. Mol Immunol 2015; 66:263-73. [PMID: 25879158 PMCID: PMC4503813 DOI: 10.1016/j.molimm.2015.03.248] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 03/18/2015] [Accepted: 03/24/2015] [Indexed: 01/28/2023]
Abstract
Mutations in C3 have been associated with aHUS and other glomerulopathies. aHUS-associated C3 mutants R592W, R161W, and I1157T impair regulation by MCP, but not by FH. EM analysis provides the structural basis for the functional impairment of the R161W and I1157T mutants. Data supports aHUS-associated C3 mutations selectively affect complement regulation on surfaces.
Atypical hemolytic uremic syndrome (aHUS) associates with complement dysregulation caused by mutations and polymorphisms in complement activators and regulators. However, the reasons why some mutations in complement proteins predispose to aHUS are poorly understood. Here, we have investigated the functional consequences of three aHUS-associated mutations in C3, R592W, R161W and I1157T. First, we provide evidence that penetrance and disease severity for these mutations is modulated by inheritance of documented “risk” haplotypes as has been observed with mutations in other complement genes. Next, we show that all three mutations markedly reduce the efficiency of factor I-mediated C3b cleavage when catalyzed by membrane cofactor protein (MCP), but not when catalyzed by factor H. Biacore analysis showed that each mutant C3b bound sMCP (recombinant soluble MCP; CD46) at reduced affinity, providing a molecular basis for its reduced cofactor activity. Lastly, we show by electron microscopy structural analysis a displacement of the TED domain from the MG ring in C3b in two of the C3 mutants that explains these defects in regulation. As a whole our data suggest that aHUS-associated mutations in C3 selectively affect regulation of complement on surfaces and provide a structural framework to predict the functional consequences of the C3 genetic variants found in patients.
Collapse
Affiliation(s)
- Rubén Martínez-Barricarte
- Centro Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain; Ciber de Enfermedades Raras, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Meike Heurich
- Institute of Infection & Immunity, School of Medicine, Cardiff University Heath Park, Cardiff CF14 4XN, United Kingdom
| | | | - Agustin Tortajada
- Centro Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain; Ciber de Enfermedades Raras, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Sheila Pinto
- Centro Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain; Ciber de Enfermedades Raras, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Margarita López-Trascasa
- Unidad de Inmunología, Hospital Universitario La Paz-IdiPAZ, and Ciber de Enfermedades Raras. Paseo de la Castellana 261, 28046 Madrid, Spain
| | - Pilar Sánchez-Corral
- Unidad de Investigación, Hospital Universitario La Paz-IdiPAZ, and Ciber de Enfermedades Raras. Paseo de la Castellana 261, 28046 Madrid, Spain
| | - B Paul Morgan
- Institute of Infection & Immunity, School of Medicine, Cardiff University Heath Park, Cardiff CF14 4XN, United Kingdom
| | - Oscar Llorca
- Centro Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Claire L Harris
- Institute of Infection & Immunity, School of Medicine, Cardiff University Heath Park, Cardiff CF14 4XN, United Kingdom
| | - Santiago Rodríguez de Córdoba
- Centro Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain; Ciber de Enfermedades Raras, Ramiro de Maeztu 9, 28040 Madrid, Spain.
| |
Collapse
|
37
|
Mapping interactions between complement C3 and regulators using mutations in atypical hemolytic uremic syndrome. Blood 2015; 125:2359-69. [PMID: 25608561 DOI: 10.1182/blood-2014-10-609073] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 01/07/2015] [Indexed: 01/22/2023] Open
Abstract
The pathogenesis of atypical hemolytic uremic syndrome (aHUS) is strongly linked to dysregulation of the alternative pathway of the complement system. Mutations in complement genes have been identified in about two-thirds of cases, with 5% to 15% being in C3. In this study, 23 aHUS-associated genetic changes in C3 were characterized relative to their interaction with the control proteins factor H (FH), membrane cofactor protein (MCP; CD46), and complement receptor 1 (CR1; CD35). In surface plasmon resonance experiments, 17 mutant recombinant proteins demonstrated a defect in binding to FH and/or MCP, whereas 2 demonstrated reduced binding to CR1. In the majority of cases, decreased binding affinity translated to a decrease in proteolytic inactivation (known as cofactor activity) of C3b via FH and MCP. These results were used to map the putative binding regions of C3b involved in the interaction with MCP and CR1 and interrogated relative to known FH binding sites. Seventy-six percent of patients with C3 mutations had low C3 levels that correlated with disease severity. This study expands our knowledge of the functional consequences of aHUS-associated C3 mutations relative to the interaction of C3 with complement regulatory proteins mediating cofactor activity.
Collapse
|