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Kojima T, Oda T. Role of complement activation in anti-neutrophil cytoplasmic antibody-associated glomerulonephritis. Front Med (Lausanne) 2022; 9:1031445. [DOI: 10.3389/fmed.2022.1031445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune disease characterized by necrotizing inflammation of small or medium vessels, causing ANCA associated glomerulonephritis (AAGN). AAGN is defined as pauci-immune glomerulonephritis with no or little immune deposition; hence, activation of the complement system in AAV was overlooked until recently. However, many studies in mice and humans have revealed a crucial role for complement system activation in the development of AAGN. Circulating and urinary detection of various complement components associated with AP activation, which have been broadly correlated with the clinical activity of AAGN, has been reported and may be useful for predicting renal outcome at the time of diagnosis and setting up personalized treatments. Moreover, recent investigations have suggested the possible contribution of the complement classical or lectin pathway activation in the development of AAGN. Thus, as therapeutic options targeting complement components are making rapid strides, the primary complement pathway involved in AAGN disease progression remains to be elucidated: this will directly impact the development of novel therapeutic strategies with high specificity and reduced side effects. This review summarizes and discusses the most recent evidence on the crucial roles of the complement system in the development of AAGN and possible therapeutic strategies that target complement components for disease management.
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2
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Galindo-Izquierdo M, Pablos Alvarez JL. Complement as a Therapeutic Target in Systemic Autoimmune Diseases. Cells 2021; 10:cells10010148. [PMID: 33451011 PMCID: PMC7828564 DOI: 10.3390/cells10010148] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/06/2021] [Accepted: 01/08/2021] [Indexed: 12/16/2022] Open
Abstract
The complement system (CS) includes more than 50 proteins and its main function is to recognize and protect against foreign or damaged molecular components. Other homeostatic functions of CS are the elimination of apoptotic debris, neurological development, and the control of adaptive immune responses. Pathological activation plays prominent roles in the pathogenesis of most autoimmune diseases such as systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, dermatomyositis, and ANCA-associated vasculitis. In this review, we will review the main rheumatologic autoimmune processes in which complement plays a pathogenic role and its potential relevance as a therapeutic target.
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3
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Cho K. Emerging Roles of Complement Protein C1q in Neurodegeneration. Aging Dis 2019; 10:652-663. [PMID: 31165008 PMCID: PMC6538225 DOI: 10.14336/ad.2019.0118] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 01/18/2019] [Indexed: 12/19/2022] Open
Abstract
The innate immune system is an ancient and primary component system that rapidly reacts to defend the body against external pathogens. C1 is the initial responder of classical pathway of the innate immune system. C1 is comprised of C1q, C1r, and C1s. Among them, C1q is known to interact with diverse ligands, which can perform various functions in physiological and pathophysiological conditions. Because C1q participates in the clearance of pathogens, its interaction with novel receptors is expected to facilitate apoptosis induction, which could prevent the onset or progression of neurodegenerative diseases and could delay the aging process. Because senescence-associated secreting phenotype determinants are generally inflammatory cytokines or immune factors to activate immune cells. In the central nervous system, C1q has diverse neuroprotective roles against pathogens and inflammation. Most of neurodegenerative diseases show region specific pathology feature in the brain. It has been suggested the evidences that the active site and amount of C1q may be disease specific. This review considers currently the emerging and under-recognized roles of C1q in neurodegeneration and highlights the need for further research to clarify these roles. Future studies on the roles of C1q in regulating disease progression should consider these aspects, including the age-dependent onset time of each neurodegenerative disease progression.
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Affiliation(s)
- Kyoungjoo Cho
- Department of Life Science, Kyonggi University, Suwon, South Korea
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4
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Nilojan J, Bathige SDNK, Kugapreethan R, Yang H, Kim MJ, Nam BH, Lee J. Molecular features and the transcriptional and functional delineation of complement system activators C1r and C1s from Sebastes schlegelii. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 81:279-290. [PMID: 29247723 DOI: 10.1016/j.dci.2017.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 12/11/2017] [Accepted: 12/11/2017] [Indexed: 06/07/2023]
Abstract
C1r and C1s are serine proteases responsible for activating the classical complement pathway to initiate the complement cascade, which plays a crucial role in eliminating invading pathogenic microbes. In this study, cDNA sequences of C1r and C1s were identified from black rockfish and designated as SsC1r and SsC1s, respectively. In both sequences, two CUB domains, an EGF-like domain, two CCP domains, and a trypsin-like serine protease domain were identified. Multiple sequence alignments with known vertebrate homologs demonstrated that both sequences were highly conserved and, especially, the catalytic and substrate binding residues were completely conserved. In the constructed phylogenetic tree, C1r and C1s formed two separate clusters, which further branched into groups of related organisms. SsC1r and SsC1s joined with their respective teleostean clusters. Transcriptional analysis showed that the highest mRNA expression level was in the liver under normal physiological conditions. Significantly upregulated expression of both mRNAs in spleen and liver after pathologic stress, by intraperitoneal injection with different stimuli, suggested their vital role in immunity. The serine protease domains of SsC1r and SsC1s were cloned and the recombinant proteins were expressed and purified. A protease assay, conducted to confirm their functionality, indicated that both recombinant proteins had proteolytic activity. Taken together, these results indicate that SsC1r and SsC1s have significant properties to aid in the immunity of black rockfish by activating the complement system by proteolytic cleavage.
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Affiliation(s)
- Jehanathan Nilojan
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea
| | - S D N K Bathige
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea; Sri Lanka Institute of Nanotechnology (SLINTEC), Nanotechnology and Science Park, Mahenwatta, Pitipana, Homagama, Sri Lanka
| | - Roopasingam Kugapreethan
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea
| | - Hyerim Yang
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea
| | - Myoung-Jin Kim
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea.
| | - Bo-Hye Nam
- Biotechnology Research Division, National Institute of Fisheries science, 408-1 Sirang-ri, Gijang-up, Gijang-gun, Busan 46083, Republic of Korea
| | - Jehee Lee
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea; Marine Science Institute, Jeju National University, Jeju Self-Governing Province 63333, Republic of Korea.
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5
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Farrero Torres M, Pando M, Luo C, Luikart H, Valantine H, Khush K. The role of complement-fixing donor-specific antibodies identified by a C1q assay after heart transplantation. Clin Transplant 2017; 31. [DOI: 10.1111/ctr.13121] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2017] [Indexed: 11/30/2022]
Affiliation(s)
- M. Farrero Torres
- Heart Failure and Heart Transplantation Program; Cardiovascular Institute, Hospital Clinic; Barcelona Spain
| | - M.J. Pando
- Department of Surgery; Scott & White Medical Center; Temple TX USA
| | - C. Luo
- Histocompatibility, Immunogenetics and Disease Profiling Laboratory; Department of Pathology; Stanford University Medical Center; Palo Alto CA USA
| | - H. Luikart
- Division of Cardiovascular Medicine; Department of Medicine; Stanford University Medical Center; Palo Alto CA USA
| | - H. Valantine
- Laboratory of Transplantation Genomics; National Institutes of Health; Bethesda MD USA
| | - K. Khush
- Division of Cardiovascular Medicine; Department of Medicine; Stanford University Medical Center; Palo Alto CA USA
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6
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Yan J, Han D, Liu C, Gao Y, Li D, Liu Y, Yang G. Staphylococcus aureus VraX specifically inhibits the classical pathway of complement by binding to C1q. Mol Immunol 2017; 88:38-44. [PMID: 28582645 DOI: 10.1016/j.molimm.2017.05.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 04/25/2017] [Accepted: 05/23/2017] [Indexed: 10/19/2022]
Abstract
VraX is a protein secreted by Staphylococcus aureus, an important human pathogen. A dramatic over expression of VraX is observed when S. aureus is exposed to several antimicrobial agents; however, its function remains unclear. Here, we aimed to reveal the function of this protein and the mechanism by which it affects the immune system to enhance the pathogenesis of the bacterium. Our results showed that VraX specifically inhibited the classical pathway of the complement system. In particular, VraX could bind to the C1q protein and block the formation of the C1 complex. Deletion of VraX decreased the pathogenesis of S. aureus. Our findings indicate that over expression of VraX might be a protective response for S. aureus survival.
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Affiliation(s)
- Jun Yan
- Beijing Institute of Basic Medical Sciences, Beijing, China; State key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
| | - Dianpeng Han
- Beijing Institute of Basic Medical Sciences, Beijing, China; State key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
| | - Chenghua Liu
- Beijing Institute of Basic Medical Sciences, Beijing, China; State key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
| | - Yaping Gao
- Beijing Institute of Basic Medical Sciences, Beijing, China; State key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
| | - Di Li
- Beijing Institute of Basic Medical Sciences, Beijing, China; State key Laboratory of Toxicology and Medical Countermeasures, Beijing, China
| | - Yu Liu
- Beijing Institute of Basic Medical Sciences, Beijing, China; State key Laboratory of Toxicology and Medical Countermeasures, Beijing, China.
| | - Guang Yang
- Beijing Institute of Basic Medical Sciences, Beijing, China; State key Laboratory of Toxicology and Medical Countermeasures, Beijing, China.
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7
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Neagu M, Piperigkou Z, Karamanou K, Engin AB, Docea AO, Constantin C, Negrei C, Nikitovic D, Tsatsakis A. Protein bio-corona: critical issue in immune nanotoxicology. Arch Toxicol 2017; 91:1031-1048. [PMID: 27438349 PMCID: PMC5316397 DOI: 10.1007/s00204-016-1797-5] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 07/06/2016] [Indexed: 01/04/2023]
Abstract
With the expansion of the nanomedicine field, the knowledge focusing on the behavior of nanoparticles in the biological milieu has rapidly escalated. Upon introduction to a complex biological system, nanomaterials dynamically interact with all the encountered biomolecules and form the protein "bio-corona." The decoration with these surface biomolecules endows nanoparticles with new properties. The present review will address updates of the protein bio-corona characteristics as influenced by nanoparticle's physicochemical properties and by the particularities of the encountered biological milieu. Undeniably, bio-corona generation influences the efficacy of the nanodrug and guides the actions of innate and adaptive immunity. Exploiting the dynamic process of protein bio-corona development in combination with the new engineered horizons of drugs linked to nanoparticles could lead to innovative functional nanotherapies. Therefore, bio-medical nanotechnologies should focus on the interactions of nanoparticles with the immune system for both safety and efficacy reasons.
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Affiliation(s)
- Monica Neagu
- Immunology Department, "Victor Babes" National Institute of Pathology, Bucharest, Romania
- Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Zoi Piperigkou
- Laboratory of Biochemistry, Biochemistry, Biochemical Analysis and Matrix Pathobiology Research Group, Department of Chemistry, University of Patras, Patras, Greece
- Foundation for Research and Technology-Hellas (FORTH)/Institute of Chemical Engineering Sciences (ICE-HT), Patras, Greece
| | - Konstantina Karamanou
- Laboratory of Biochemistry, Biochemistry, Biochemical Analysis and Matrix Pathobiology Research Group, Department of Chemistry, University of Patras, Patras, Greece
- Laboratório de Bioquímica e Biologia Cellular de Glicoconjugados, Programa de Glicobiologia, Instituto de Bioquímica Médica Leopoldo De Meis and Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ayse Basak Engin
- Department of Toxicology, Faculty of Pharmacy, Gazi University, Ankara, Turkey
| | - Anca Oana Docea
- Department of Toxicology, Faculty of Pharmacy University of Medicine and Pharmacy Craiova, Craiova, Romania
| | - Carolina Constantin
- Immunology Department, "Victor Babes" National Institute of Pathology, Bucharest, Romania
| | - Carolina Negrei
- Department of Toxicology, Faculty of Pharmacy, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
| | - Dragana Nikitovic
- Laboratory of Anatomy-Histology-Embryology, Medical School, University of Crete, Heraklion, Greece
| | - Aristidis Tsatsakis
- Department of Toxicology and Forensic Sciences, Medical School, University of Crete, Heraklion, Greece.
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SALO, a novel classical pathway complement inhibitor from saliva of the sand fly Lutzomyia longipalpis. Sci Rep 2016; 6:19300. [PMID: 26758086 PMCID: PMC4725370 DOI: 10.1038/srep19300] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 12/09/2015] [Indexed: 01/20/2023] Open
Abstract
Blood-feeding insects inject potent salivary components including complement inhibitors into their host’s skin to acquire a blood meal. Sand fly saliva was shown to inhibit the classical pathway of complement; however, the molecular identity of the inhibitor remains unknown. Here, we identified SALO as the classical pathway complement inhibitor. SALO, an 11 kDa protein, has no homology to proteins of any other organism apart from New World sand flies. rSALO anti-complement activity has the same chromatographic properties as the Lu. longipalpis salivary gland homogenate (SGH)counterparts and anti-rSALO antibodies blocked the classical pathway complement activity of rSALO and SGH. Both rSALO and SGH inhibited C4b deposition and cleavage of C4. rSALO, however, did not inhibit the protease activity of C1s nor the enzymatic activity of factor Xa, uPA, thrombin, kallikrein, trypsin and plasmin. Importantly, rSALO did not inhibit the alternative or the lectin pathway of complement. In conclusion our data shows that SALO is a specific classical pathway complement inhibitor present in the saliva of Lu. longipalpis. Importantly, due to its small size and specificity, SALO may offer a therapeutic alternative for complement classical pathway-mediated pathogenic effects in human diseases.
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9
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IgG subclass specificity to C1q determined by surface plasmon resonance using Protein L capture technique. Anal Biochem 2015; 479:15-7. [DOI: 10.1016/j.ab.2015.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 03/04/2015] [Accepted: 03/11/2015] [Indexed: 12/17/2022]
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Yadav S, Gupta S, Selvaraj C, Doharey PK, Verma A, Singh SK, Saxena JK. In silico and in vitro studies on the protein-protein interactions between Brugia malayi immunomodulatory protein calreticulin and human C1q. PLoS One 2014; 9:e106413. [PMID: 25184227 PMCID: PMC4153637 DOI: 10.1371/journal.pone.0106413] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 07/31/2014] [Indexed: 12/20/2022] Open
Abstract
Filarial parasites modulate effective immune response of their host by releasing a variety of immunomodulatory molecules, which help in the long persistence of the parasite within the host. The present study was aimed to characterize an immunomodulatory protein of Brugia malayi and its interaction with the host immune component at the structural and functional level. Our findings showed that Brugia malayi Calreticulin (BmCRT) is responsible for the prevention of classical complement pathway activation via its interaction with the first component C1q of the human host. This was confirmed by inhibition of C1q dependent lysis of immunoglobulin-sensitized Red Blood Cells (S-RBCs). This is possibly the first report which predicts CRT-C1q interaction on the structural content of proteins to explain how BmCRT inhibits this pathway. The molecular docking of BmCRT-C1q complex indicated that C1qB chain (IgG/M and CRP binding sites on C1q) played a major role in the interaction with conserved and non-conserved regions of N and P domain of BmCRT. Out of 37 amino acids of BmCRT involved in the interaction, nine amino acids (Pro(126), Glu(132), His(147), Arg(151), His(153), Met(154), Lys(156), Ala(196) and Lys(212)) are absent in human CRT. Both ELISA and in silico analysis showed the significant role of Ca(+2) in BmCRT-HuC1q complex formation and deactivation of C1r2-C1s2. Molecular dynamics studies of BmCRT-HuC1q complex showed a deviation from ∼ 0.4 nm to ∼ 1.0 nm. CD analyses indicated that BmCRT is composed of 49.6% α helix, 9.6% β sheet and 43.6% random coil. These findings provided valuable information on the architecture and chemistry of BmCRT-C1q interaction and supported the hypothesis that BmCRT binds with huC1q at their targets (IgG/M, CRP) binding sites. This interaction enables the parasite to interfere with the initial stage of host complement activation, which might be helpful in parasites establishment. These results might be utilized for help in blocking the C1q/CRT interaction and preventing parasite infection.
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Affiliation(s)
- Sunita Yadav
- Division of Biochemistry, CSIR-Central Drug Research Institute, BS10/1, Sector 10, Jankipuram extension, Lucknow, Uttar Pradesh, India
| | - Smita Gupta
- Division of Biochemistry, CSIR-Central Drug Research Institute, BS10/1, Sector 10, Jankipuram extension, Lucknow, Uttar Pradesh, India
| | - Chandrabose Selvaraj
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Alagappa University, Karaikudi, Tamilnadu, India
| | - Pawan Kumar Doharey
- Division of Biochemistry, CSIR-Central Drug Research Institute, BS10/1, Sector 10, Jankipuram extension, Lucknow, Uttar Pradesh, India
| | - Anita Verma
- Division of Biochemistry, CSIR-Central Drug Research Institute, BS10/1, Sector 10, Jankipuram extension, Lucknow, Uttar Pradesh, India
| | - Sanjeev Kumar Singh
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Alagappa University, Karaikudi, Tamilnadu, India
| | - Jitendra Kumar Saxena
- Division of Biochemistry, CSIR-Central Drug Research Institute, BS10/1, Sector 10, Jankipuram extension, Lucknow, Uttar Pradesh, India
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Yang P, Baciu P, Kerrigan BCP, Etheridge M, Sung E, Toimil BA, Berchuck JE, Jaffe GJ. Retinal pigment epithelial cell death by the alternative complement cascade: role of membrane regulatory proteins, calcium, PKC, and oxidative stress. Invest Ophthalmol Vis Sci 2014; 55:3012-21. [PMID: 24677108 DOI: 10.1167/iovs.13-13554] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
PURPOSE Retinal pigment epithelial (RPE) cell death is an important feature of the advanced forms of AMD. Complement alternative pathway (AP) activation is associated with RPE cell death in AMD. In this study, we developed a new model to initiate AP activation on RPE cells and investigated the cellular mechanisms modulating AP activation-mediated RPE cell death. METHODS An anti-RPE antibody was developed. A spontaneously arising human RPE cell line (ARPE-19) and donor RPE cells were primed with this antibody followed by stimulation with 6% C1q-depleted human serum (C1q-Dep) to activate AP. Complement activation was evaluated by flow cytometry and immunofluorescent staining. Cellular response to complement activation was examined by measurement of intracellular calcium and adenosine triphosphate (ATP) release. Cell viability was assessed by Sytox orange, tetrazolium salt, and lactate dehydrogenase release assays. RESULTS Alternative pathway complement-mediated RPE cell death was associated with membrane attack complex formation and a rapid rise in intracellular calcium followed by release of ATP. Downregulation of membrane complement regulatory proteins and protein kinase C (PKC) inhibition increased cell susceptibility to complement attack. Pretreatment of RPE cells with either hydrogen peroxide or hydroquinone enhanced cell death. Chronic repetitive treatment of RPE cells with low levels of oxidants also enhanced complement-mediated cell death. CONCLUSIONS Activation of complement through the alternative pathway induces sublytic and lytic phases of complement attack on RPE cells, leading to cell death modulated by extracellular calcium, membrane complement regulatory proteins, and intracellular signaling mechanisms. Single-dose oxidant exposure and low-dose repetitive oxidant exposure rendered RPE cells more susceptible to complement-mediated death.
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Affiliation(s)
- Ping Yang
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States
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12
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Tailoring immunoglobulin Fc for highly potent and serum-stable therapeutic antibodies. BIOTECHNOL BIOPROC E 2013. [DOI: 10.1007/s12257-012-0711-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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13
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A missense mutation (c.1963A<G) of the complementary component 2 (C2) gene is associated with serum Ca⁺⁺ concentrations in pigs. Mol Biol Rep 2012; 39:9291-7. [PMID: 22763733 DOI: 10.1007/s11033-012-1679-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 06/05/2012] [Indexed: 10/28/2022]
Abstract
Serum Ca(++) levels play important roles in the humoral immunity. The aim of this study was to detect quantitative trait loci and the associated positional candidate genes affecting baseline serum Ca(++) concentrations. A genome-wide association study was conducted in an F(2) intercross population between Landrace and Korean native pigs using the porcine single nucleotide polymorphism (SNP) 60 K beadchip and the PLINK program based on linear regression. Data used in the study included 410 F(2) pigs. All experimental animals were genotyped with 36,613 SNP markers located throughout the pig autosomes. We identified a strong association between a SNP marker on chromosome 7 and serum Ca(++) levels (DIAS0002191, genomic control-corrected P = 7.7 × 10(-5)). The position of DIAS0002191 was closely located to SLA class III region containing the C2 gene encoding the complementary component 2 protein, a protein which is important in the humoral immune responses. De novo sequencing of the porcine C2 gene revealed a missense mutation [c.1963A<G (N655D)] and this missense mutation was also strongly associated with serum Ca(++) concentrations (genomic control-corrected P = 5.9 × 10(-5)). Further studies are necessary to investigate the effect of this missense mutation at a functional-molecular level. In conclusion, the missense mutation of the C2 gene identified in this study may help in elucidating the genetic factors underlying humoral immune reactions.
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Huang H, Huang S, Yu Y, Yuan S, Li R, Wang X, Zhao H, Yu Y, Li J, Yang M, Xu L, Chen S, Xu A. Functional characterization of a ficolin-mediated complement pathway in amphioxus. J Biol Chem 2011; 286:36739-48. [PMID: 21832079 PMCID: PMC3196118 DOI: 10.1074/jbc.m111.245944] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 07/20/2011] [Indexed: 12/28/2022] Open
Abstract
The ficolin-mediated complement pathway plays an important role in vertebrate immunity, but it is not clear whether this pathway exists in invertebrates. Here we identified homologs of ficolin pathway components from the cephalochordate amphioxus and investigated whether they had been co-opted into a functional ficolin pathway. Four of these homologs, ficolin FCN1, serine protease MASP1 and MASP3, and complement component C3, were highly expressed in mucosal tissues and gonads, and were significantly up-regulated following bacterial infection. Recombinant FCN1 could induce hemagglutination, discriminate among sugar components, and specifically recognize and aggregate several bacteria (especially gram-positive strains) without showing bactericidal activity. This suggested that FCN1 is a dedicated pattern-recognition receptor. Recombinant serine protease MASP1/3 formed complexes with recombinant FCN1 and facilitated the activation of native C3 protein in amphioxus humoral fluid, in which C3 acted as an immune effector. We conclude that amphioxus have developed a functional ficolin-complement pathway. Because ficolin pathway components have not been reported in non-chordate species, our findings supported the idea that this pathway may represent a chordate-specific innovation in the evolution of the complement system.
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Affiliation(s)
- Huiqing Huang
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Shengfeng Huang
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Yingcai Yu
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Shaochun Yuan
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Rui Li
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Xin Wang
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Hongchen Zhao
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Yanhong Yu
- the Institute of Reproductive Immunology, Jinan University, Guangzhou 510632, People's Republic of China
| | - Jun Li
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Manyi Yang
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Liqun Xu
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Shangwu Chen
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
| | - Anlong Xu
- From the Department of Biochemistry, College of Life Sciences, State Key Laboratory of Biocontrol, National Engineering Research Center of South China Sea Marine Biotechnology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China and
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15
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Carroll MV, Sim RB. Complement in health and disease. Adv Drug Deliv Rev 2011; 63:965-75. [PMID: 21704094 DOI: 10.1016/j.addr.2011.06.005] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 06/06/2011] [Accepted: 06/09/2011] [Indexed: 12/16/2022]
Abstract
The complement system consists of about 35-40 proteins and glycoproteins present in blood plasma or on cell surfaces. Its main biological function is to recognise "foreign" particles and macromolecules, and to promote their elimination either by opsonisation or lysis. Although historically complement has been studied as a system for immune defence against bacteria, it has an important homeostatic role in which it recognises damaged or altered "self" components. Thus complement has major roles in both immune defence against microorganisms, and in clearance of damaged or "used" host components. Since complement proteins opsonise or lyse cells, complement can damage healthy host cells and tissues. The system is regulated by many endogenous regulatory proteins. Regulation is sometimes imperfect and both too much and too little complement activation is associated with many diseases. Excessive or inappropriate activation can cause tissue damage in diseases such as rheumatoid arthritis, age-related macular degeneration (AMD), multiple sclerosis, ischemia-reperfusion injury (e.g. ischemic stroke). Insufficient complement activity is associated with susceptibility to infection (mainly bacterial) and development of autoimmune disease, like SLE (systemic lupus erythematosus).
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16
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Ramírez G, Valck C, Ferreira VP, López N, Ferreira A. Extracellular Trypanosoma cruzi calreticulin in the host-parasite interplay. Trends Parasitol 2011; 27:115-22. [PMID: 21288773 DOI: 10.1016/j.pt.2010.12.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 12/18/2010] [Accepted: 12/20/2010] [Indexed: 11/24/2022]
Abstract
Calreticulin (CRT) from vertebrates is a calcium-binding protein present mainly in the endoplasmic reticulum (ER). There, it directs the conformation of proteins and controls calcium levels. This review will focus on several extracellular roles of Trypanosoma cruzi CRT (TcCRT) in relation to its capacity to inhibit the complement system, mediate parasite infectivity, interfere with angiogenesis and, as a possible consequence, with tumor growth. The TcCRT antiangiogenic effect parallels with the capacity of T. cruzi infection to inhibit tumor development in vivo. Thus, the TcCRT, complement, and endothelial cell interactions seem to be an evolutionary adaptation to promote prolonged parasite-host relationships.
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Affiliation(s)
- Galia Ramírez
- Programa Disciplinario de Inmunología, ICBM, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile
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17
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Infections of people with complement deficiencies and patients who have undergone splenectomy. Clin Microbiol Rev 2010; 23:740-80. [PMID: 20930072 DOI: 10.1128/cmr.00048-09] [Citation(s) in RCA: 252] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The complement system comprises several fluid-phase and membrane-associated proteins. Under physiological conditions, activation of the fluid-phase components of complement is maintained under tight control and complement activation occurs primarily on surfaces recognized as "nonself" in an attempt to minimize damage to bystander host cells. Membrane complement components act to limit complement activation on host cells or to facilitate uptake of antigens or microbes "tagged" with complement fragments. While this review focuses on the role of complement in infectious diseases, work over the past couple of decades has defined several important functions of complement distinct from that of combating infections. Activation of complement in the fluid phase can occur through the classical, lectin, or alternative pathway. Deficiencies of components of the classical pathway lead to the development of autoimmune disorders and predispose individuals to recurrent respiratory infections and infections caused by encapsulated organisms, including Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. While no individual with complete mannan-binding lectin (MBL) deficiency has been identified, low MBL levels have been linked to predisposition to, or severity of, several diseases. It appears that MBL may play an important role in children, who have a relatively immature adaptive immune response. C3 is the point at which all complement pathways converge, and complete deficiency of C3 invariably leads to severe infections, including those caused by meningococci and pneumococci. Deficiencies of the alternative and terminal complement pathways result in an almost exclusive predisposition to invasive meningococcal disease. The spleen plays an important role in antigen processing and the production of antibodies. Splenic macrophages are critical in clearing opsonized encapsulated bacteria (such as pneumococci, meningococci, and Escherichia coli) and intraerythrocytic parasites such as those causing malaria and babesiosis, which explains the fulminant nature of these infections in persons with anatomic or functional asplenia. Paramount to the management of patients with complement deficiencies and asplenia is educating patients about their predisposition to infection and the importance of preventive immunizations and seeking prompt medical attention.
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18
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C1q nephropathy in the pediatric population: pathology and pathogenesis. Pediatr Nephrol 2010; 25:1385-96. [PMID: 20180137 DOI: 10.1007/s00467-009-1429-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 12/11/2009] [Accepted: 12/15/2009] [Indexed: 10/19/2022]
Abstract
C1q nephropathy was originally described nearly 25 years ago by Jennette and Hipp. Since that time there have been a limited number of publications on C1q nephropathy, most of them in the pediatric literature. Despite reported incidences as high as 16% in some pediatric biopsy series, a consensus definition on the diagnosis of C1q nephropathy is lacking and its existence as a distinct clinical disease entity remains controversial. The purpose of this review is to discuss the biology of C1q in the context of mechanisms of C1q deposition, and to provide a detailed analysis of the published pediatric case series with a focus on the pathological criteria used to establish the diagnosis of C1q nephropathy as well as long-term outcomes in children.
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19
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Brier S, Pflieger D, Le Mignon M, Bally I, Gaboriaud C, Arlaud GJ, Daniel R. Mapping surface accessibility of the C1r/C1s tetramer by chemical modification and mass spectrometry provides new insights into assembly of the human C1 complex. J Biol Chem 2010; 285:32251-63. [PMID: 20592021 DOI: 10.1074/jbc.m110.149112] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
C1, the complex that triggers the classic pathway of complement, is a 790-kDa assembly resulting from association of a recognition protein C1q with a Ca(2+)-dependent tetramer comprising two copies of the proteases C1r and C1s. Early structural investigations have shown that the extended C1s-C1r-C1r-C1s tetramer folds into a compact conformation in C1. Recent site-directed mutagenesis studies have identified the C1q-binding sites in C1r and C1s and led to a three-dimensional model of the C1 complex (Bally, I., Rossi, V., Lunardi, T., Thielens, N. M., Gaboriaud, C., and Arlaud, G. J. (2009) J. Biol. Chem. 284, 19340-19348). In this study, we have used a mass spectrometry-based strategy involving a label-free semi-quantitative analysis of protein samples to gain new structural insights into C1 assembly. Using a stable chemical modification, we have compared the accessibility of the lysine residues in the isolated tetramer and in C1. The labeling data account for 51 of the 73 lysine residues of C1r and C1s. They strongly support the hypothesis that both C1s CUB(1)-EGF-CUB(2) interaction domains, which are distant in the free tetramer, associate with each other in the C1 complex. This analysis also provides the first experimental evidence that, in the proenzyme form of C1, the C1s serine protease domain is partly positioned inside the C1q cone and yields precise information about its orientation in the complex. These results provide further structural insights into the architecture of the C1 complex, allowing significant improvement of our current C1 model.
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Affiliation(s)
- Sébastien Brier
- CNRS, UMR 8587, Université d'Evry-Val-d'Essonne, Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement, Boulevard François Mitterrand, 91025 Evry, France.
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20
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Development of a humanized C1q A chain knock-in mouse: assessment of antibody independent beta-amyloid induced complement activation. Mol Immunol 2008; 45:3244-52. [PMID: 18400300 DOI: 10.1016/j.molimm.2008.02.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 02/20/2008] [Accepted: 02/26/2008] [Indexed: 11/22/2022]
Abstract
Evidence has been accumulating for a role of inflammation in the development of Alzheimer's disease (AD), a progressive neurodegenerative disorder causing a common form of dementia in the elderly. C1q, part of the initiation component of the classical complement pathway (CCP), is associated with beta-sheet, fibrillar amyloid plaques in AD brain. In vitro, beta-amyloid peptide in fibrillar beta-sheet conformation (fAbeta) can activate CCP via interaction of specific negatively charged amino acids of the beta-amyloid fibril with human C1q. Previous results using peptide inhibitors led to the hypothesis that a highly positively charged domain consisting of three arginine residues, such as that present in the N-terminal collagen-like region of the human C1q A chain, may be critical for the activation event. However, mouse C1q A chain lacks two of the three arginines in the corresponding C1q A chain collagen-like region. To test the hypothesis that this divergent activation domain results in a weaker C' activation and thus may contribute to the lower neuronal loss observed in transgenic mouse models of AD, a partially humanized C1q A chain knock-in mouse was generated. The mouse C1q A chain gene was modified by homologous recombination to replace 4 residues in the 13-20 amino acid region to mimic the corresponding sequence from human A chain. No significant differences in the expression of C1q were found in sera from mice homozygous for the humanized C1q A chain compared to littermate wild type mice. Two distinct C1 activation assays demonstrated that activation by fAbeta was not significantly different in the homozygous humanized C1q A chain mice. Activation of C1 by DNA, previously hypothesized to interact with this C1q A chain arginine-rich sequence was also not significantly different in the knock-in mouse. Molecular modeling based on the published crystal structure of human C1q B chain globular head and a beta-sheet model for fibrillar amyloid suggests an alternative arginine ladder in the globular head domain may provide the functional C1 activating interaction domains. The humanized C1q mouse generated here should provide a better animal model for assessing the mechanisms of C1 activation and the contribution of C1q to human health and disease.
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21
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Tacnet P, Cheong ECC, Goeltz P, Ghebrehiwet B, Arlaud GJ, Liu XY, Lesieur C. Trimeric reassembly of the globular domain of human C1q. BIOCHIMICA ET BIOPHYSICA ACTA 2008; 1784:518-29. [PMID: 18179779 PMCID: PMC2707929 DOI: 10.1016/j.bbapap.2007.12.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 11/19/2007] [Accepted: 12/03/2007] [Indexed: 11/25/2022]
Abstract
C1q is a versatile recognition protein which binds to a variety of targets and consequently triggers the classical pathway of complement. C1q is a hetero-trimer composed of three chains (A, B and C) arranged in three domains, a short N-terminal region, followed by a collagenous repeat domain that gives rise to the formation of (ABC) triple helices, each ending in a C-terminal hetero-trimeric globular domain, called gC1q, which is responsible for the recognition properties of C1q. The mechanism of the trimeric assembly of C1q and in particular the role of each domain in the process is unknown. Here, we have investigated if the gC1q domain was able to assemble into functional trimers, in vitro, in the absence of the collagenous domain, a motif known to promote obligatory trimers in other proteins. Acid-mediated gC1q protomers reassembled into functional trimers, once neutralized, indicating that it is the gC1q domain which possesses the information for trimerization. However, reassembly occurred after neutralization, only if the gC1q protomers had preserved a residual tertiary structure at the end of the acidic treatment. Thus, the collagenous domain of C1q might initialize the folding of the gC1q domain so that subsequent assembly of the entire molecule can occur.
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Affiliation(s)
- Pascale Tacnet
- Laboratoire d’Enzymologie Moléculaire, Institut de Biologie Structurale, CEA-CNRS-Université Joseph Fourier, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
| | - Eric Chung Chee Cheong
- National University of Singapore, Physics Department, 2 Science Drive 3, 117542, Singapore
| | - Pierrette Goeltz
- Laboratoire d’Enzymologie Moléculaire, Institut de Biologie Structurale, CEA-CNRS-Université Joseph Fourier, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
| | - Berhane Ghebrehiwet
- Department of Medicine, State University of New York, Stony Brook, New York, USA
| | - Gérard J. Arlaud
- Laboratoire d’Enzymologie Moléculaire, Institut de Biologie Structurale, CEA-CNRS-Université Joseph Fourier, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
| | - Xiang-Yang Liu
- National University of Singapore, Physics Department, 2 Science Drive 3, 117542, Singapore
| | - Claire Lesieur
- National University of Singapore, Physics Department, 2 Science Drive 3, 117542, Singapore
- iRTSV/BBSI, CEA-CNRS-Université Joseph Fourier, 17 rue des Martyrs, 38054 Grenoble, France
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22
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Travins JM, Ali F, Huang H, Ballentine SK, Khalil E, Hufnagel HR, Pan W, Gushue J, Leonard K, Bone RF, Soll RM, DesJarlais RL, Crysler CS, Ninan N, Kirkpatrick J, Cummings MD, Huebert N, Molloy CJ, Gaul M, Tomczuk BE, Subasinghe NL. Biphenylsulfonyl-thiophene-carboxamidine inhibitors of the complement component C1s. Bioorg Med Chem Lett 2008; 18:1603-6. [PMID: 18242991 DOI: 10.1016/j.bmcl.2008.01.064] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2007] [Revised: 01/14/2008] [Accepted: 01/16/2008] [Indexed: 11/28/2022]
Abstract
Complement activation has been implicated in disease states such as hereditary angioedema, ischemia-reperfusion injury, acute respiratory distress syndrome, and acute transplant rejection. Even though the complement cascade provides several protein targets for potential therapeutic intervention only two complement inhibitors have been approved so far for clinical use including anti-C5 antibodies for the treatment of paroxysmal nocturnal hemoglobinuria and purified C1-esterase inhibitor replacement therapy for the control of hereditary angioedema flares. In the present study, optimization of potency and physicochemical properties of a series of thiophene amidine-based C1s inhibitors with potential utility as intravenous agents for the inhibition of the classical pathway of complement is described.
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Affiliation(s)
- Jeremy M Travins
- Johnson & Johnson Pharmaceutical Research and Development, L.L.C., 665 Stockton Drive, Exton, PA 19341, USA
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23
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Rawal N, Rajagopalan R, Salvi VP. Activation of complement component C5: comparison of C5 convertases of the lectin pathway and the classical pathway of complement. J Biol Chem 2008; 283:7853-63. [PMID: 18204047 DOI: 10.1074/jbc.m707591200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although the initiating complex of lectin pathway (called M1 in this study) generates C3/C5 convertases similar to those assembled by the initiating complex (C1) of the classical pathway, activation of complement component C5 via the lectin pathway has not been examined. In the present study kinetic analysis of lectin pathway C3/C5 convertases assembled on two surfaces (zymosan and sheep erythrocytes coated with mannan (E(Man))) revealed that the convertases (ZymM1,C4b,C2a and E(Man)M1,C4b,C2a) exhibited a similar but weak affinity for the substrate, C5 indicated by a high K(m) (2.73-6.88 microm). Very high affinity C5 convertases were generated when the low affinity C3/C5 convertases were allowed to deposit C3b by cleaving native C3. These C3b-containing convertases exhibited K(m) (0.0086-0.0075 microm) well below the normal concentration of C5 in blood (0.37 microm). Although kinetic parameters, K(m) and k(cat), of the lectin pathway C3/C5 convertases were similar to those reported for classical pathway C3/C5 convertases, studies on the ability of C4b to bind C2 indicated that every C4b deposited on zymosan or E(Man) was capable of forming a convertase. These findings differ from those reported for the classical pathway C3/C5 convertase, where only one of four C4b molecules deposited formed a convertase. The potential for four times more amplification via the lectin pathway than the classical pathway in the generation of C3/C5 convertases and production of pro-inflammatory products, such as C3a, C4a, and C5a, implies that activation of complement via the lectin pathway might be a more prominent contributor to the pathology of inflammatory reactions.
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Affiliation(s)
- Nenoo Rawal
- Department of Biochemistry, University of Texas Health Science Center, Tyler, Texas 75708, USA.
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24
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Subasinghe NL, Travins JM, Ali F, Huang H, Ballentine SK, Marugán JJ, Khalil E, Hufnagel HR, Bone RF, DesJarlais RL, Crysler CS, Ninan N, Cummings MD, Molloy CJ, Tomczuk BE. A novel series of arylsulfonylthiophene-2-carboxamidine inhibitors of the complement component C1s. Bioorg Med Chem Lett 2006; 16:2200-4. [PMID: 16460935 DOI: 10.1016/j.bmcl.2006.01.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 01/10/2006] [Accepted: 01/11/2006] [Indexed: 11/23/2022]
Abstract
Inhibiting the classical pathway of complement activation by attenuating the proteolytic activity of the serine protease C1s is a potential strategy for the therapeutic intervention in disease states such as hereditary angioedema, ischemia-reperfusion injury, and acute transplant rejection. A series of arylsulfonylthiophene-2-carboxamidine inhibitors of C1s were synthesized and evaluated for C1s inhibitory activity. The most potent compound had a Ki of 10nM and >1000-fold selectivity over uPA, tPA, FX(a), thrombin, and plasmin.
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Affiliation(s)
- Nalin L Subasinghe
- Johnson & Johnson Pharmaceutical Research and Development, L.L.C., 665 Stockton Drive, Exton, PA 19341, USA.
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25
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Waggoner SN, Cruise MW, Kassel R, Hahn YS. gC1q receptor ligation selectively down-regulates human IL-12 production through activation of the phosphoinositide 3-kinase pathway. THE JOURNAL OF IMMUNOLOGY 2005; 175:4706-14. [PMID: 16177118 DOI: 10.4049/jimmunol.175.7.4706] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
gC1qR, a complement receptor for C1q, plays a pivotal role in the regulation of inflammatory and antiviral T cell responses. Several pathogens, including hepatitis C virus, exploit gC1qR-dependent regulatory pathways to manipulate host immunity. However, the molecular mechanism(s) of gC1qR signaling involved in regulating inflammatory responses remains unknown. We report the selective inhibition of TLR4-induced IL-12 production after cross-linking of gC1qR on the surface of macrophages and dendritic cells. Suppression of IL-12 did not result from increased IL-10 or TGF-beta, but was dependent on PI3K activation. Activation of PI3K and subsequent phosphorylation of Akt define an intracellular pathway mediating gC1qR signaling and cross-talk with TLR4 signaling. This is the first report to identify signaling pathways used by gC1qR-mediated immune suppression, and it establishes a means of complement-mediated immune suppression to inhibit Th1 immunity crucial for clearing pathogenic infection.
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Affiliation(s)
- Stephen N Waggoner
- Beirne Carter Center for Immunology Research, University of Virginia, Charlottesville 22908, USA
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26
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Abstract
Osteolytic bone disease is a frequent complication of multiple myeloma, resulting in skeletal complications that are a significant cause of morbidity and mortality. A characteristic feature of myeloma bone disease is that the lesions rarely heal and bone scans are often negative in myeloma patients who have extensive lytic lesions, offering very little in the follow-up of bone disease. X-rays are also of limited value in monitoring bone destruction during anti-myeloma or anti-resorptive treatment. Biochemical markers of bone turnover, such as N- and C-terminal cross-linking telopeptide of type I collagen (NTX, CTX/ICTP, respectively), and newer ones such as the tartrate resistant acid phosphatase isoform 5b, provide information on bone dynamics that in turn may reflect disease activity in bone. Several studies have shown bone markers to be elevated in myeloma patients and reflect the extent of bone disease, while in some of them bone resorption markers correlate with survival. These markers may also be helpful in identifying those patients likely to respond to bisphosphonate treatment, and monitoring the effectiveness of bisphosphonate therapy in the management of myeloma bone disease. This review attempts to summarize the existing data for the role of markers of bone remodeling in assessing the extent of bone destruction in myeloma and monitoring bone turnover during specific anti-myeloma treatment. We also discuss some novel markers that may be of particular interest in the near future.
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Affiliation(s)
- Evangelos Terpos
- Department of Hematology, Faculty of Medicine, Imperial College London, Hammersmith Hospital, W12 0NN London, UK.
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27
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Kishore U, Ghai R, Greenhough TJ, Shrive AK, Bonifati DM, Gadjeva MG, Waters P, Kojouharova MS, Chakraborty T, Agrawal A. Structural and functional anatomy of the globular domain of complement protein C1q. Immunol Lett 2005; 95:113-28. [PMID: 15388251 PMCID: PMC3818097 DOI: 10.1016/j.imlet.2004.06.015] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Accepted: 06/23/2004] [Indexed: 02/06/2023]
Abstract
C1q is the first subcomponent of the classical pathway of the complement system and a major connecting link between innate and acquired immunity. As a versatile charge pattern recognition molecule, C1q is capable of engaging a broad range of ligands via its heterotrimeric globular domain (gC1q) which is composed of the C-terminal regions of its A (ghA), B (ghB) and C (ghC) chains. Recent studies using recombinant forms of ghA, ghB and ghC have suggested that the gC1q domain has a modular organization and each chain can have differential ligand specificity. The crystal structure of the gC1q, molecular modeling and protein engineering studies have combined to illustrate how modular organization, charge distribution and the spatial orientation of the heterotrimeric assembly offer versatility of ligand recognition to C1q. Although the biochemical and structural studies have provided novel insights into the structure-function relationships within the gC1q domain, they have also raised many unexpected issues for debate.
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Affiliation(s)
- Uday Kishore
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK.
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28
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Rooijakkers SHM, van Wamel WJB, Ruyken M, van Kessel KPM, van Strijp JAG. Anti-opsonic properties of staphylokinase. Microbes Infect 2005; 7:476-84. [PMID: 15792635 DOI: 10.1016/j.micinf.2004.12.014] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Revised: 12/07/2004] [Accepted: 12/10/2004] [Indexed: 12/19/2022]
Abstract
Recently we described a novel bacteriophage-encoded pathogenicity island in Staphylococcus aureus that harbors a number of virulence factors that are all involved in the evasion of innate immunity. Here we describe a mechanism by which staphylokinase (SAK), frequently present on this pathogenicity island, interferes with innate immune defenses: SAK is anti-opsonic. By activating human plasminogen (PLG) into plasmin (PL) at the bacterial surface, it creates bacterium-bound serine protease activity that leads to degradation of two major opsonins: human immunoglobulin G (IgG) and human C3b. Incubation of opsonized bacteria with PLG and SAK resulted in removal of anti-staphylococcal IgGs and C3b from the bacterial surface. In phagocytosis assays this proved to be a very efficient mechanism to reduce the opsonic activity of human IgG and serum. The fact that SAK activates human PLG at the bacterial surface and removes IgG as well as C3b makes this protein a unique anti-opsonic molecule.
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Affiliation(s)
- S H M Rooijakkers
- Eijkman Winkler Institute, University Medical Center (UMCU) G04-614, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
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29
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Wicher KB, Fries E. Prohaptoglobin is proteolytically cleaved in the endoplasmic reticulum by the complement C1r-like protein. Proc Natl Acad Sci U S A 2004; 101:14390-5. [PMID: 15385675 PMCID: PMC521962 DOI: 10.1073/pnas.0405692101] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Many secretory proteins are synthesized as proforms that become biologically active through a proteolytic cleavage in the trans-Golgi complex or at a later stage in the secretory pathway. Haptoglobin (Hp) is unusual in that it is cleaved in the endoplasmic reticulum before it enters the Golgi. Here, we present evidence that the recently discovered complement C1r-like protein (C1r-LP) mediates this cleavage. C1r-LP has not previously been shown to possess proteolytic activity, despite its homology to trypsin-like Ser proteinases. We demonstrate that coexpression of the proform of Hp (proHp) and C1r-LP in COS-1 cells effected cleavage of proHp in the endoplasmic reticulum. This cleavage depended on proteolytic activity of C1r-LP because mutation of the putative active-site Ser residue abolished the reaction. Furthermore, incubation of affinity-purified C1r-LP and proHp led to the cleavage of the latter protein. ProHp appeared to be cleaved at the expected site because substitution of Gly for Arg-161 blocked the reaction. C1r-LP showed specificity for proHp, in that it did not cleave the proform of complement C1s, a protein similar to Hp particularly around the cleavage site. C1r-LP accounts for at least part of the endogenous proHp-cleavage activity because suppression of the C1r-LP expression by RNA interference reduced the cleavage of proHp by up to 45% in the cells of a human hepatoma cell line (HepG2).
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Affiliation(s)
- Krzysztof B Wicher
- Department of Medical Biochemistry and Microbiology, Uppsala University, P.O. Box 582, S-751 23 Uppsala, Sweden.
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30
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Steinø A, Jørgensen CS, Laursen I, Houen G. Interaction of C1q with the receptor calreticulin requires a conformational change in C1q. Scand J Immunol 2004; 59:485-95. [PMID: 15140059 DOI: 10.1111/j.0300-9475.2004.01425.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The interaction between C1q and the chaperone calreticulin was studied under various conditions. When both proteins were present in equal amounts in solution, no interaction could be demonstrated. However, C1q immobilized on a hydrophobic surface, exposed to heat-treatment or bound to immunoglobulins (Igs) showed a strong, rapid and specific binding of calreticulin. The interaction appeared to be a two-step process, and the initial phase of interaction was sensitive to high concentrations of salt but not to a physiological salt concentration. The following strong binding was insensitive to salt and extremes of pH but sensitive to strongly denaturing agents (urea and guanidine). The sensitivity to salt during the initial phase of interaction was practically identical to that observed when calreticulin was bound to type V collagen. Binding between C1q and calreticulin could be inhibited by serum amyloid P component and by proteinase K-digested ovalbumin, and the binding of calreticulin to proteinase K-digested ovalbumin was shown to be inhibited by C1q. The data indicate that C1q binds stably to the peptide-binding site of calreticulin and that the initial binding of calreticulin to C1q involves the collagen-like domain of the C1q molecule. In conclusion, our results suggest calreticulin as a potential receptor for an altered conformation of C1q as occurs during binding to Igs. Thus, the chaperone and protein-scavenging function of calreticulin may extend from the endoplasmic reticulum to the topologically equivalent cell surface, where it may contribute to the elimination of immune complexes and apoptotic cells.
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Affiliation(s)
- A Steinø
- Department of Research and Development, Statens Serum Institut, Copenhagen, Denmark
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31
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Abstract
The complement system, composed of more than 30 serum and cell surface components, is collaborating in recognition and elimination of pathogens as a part of both the innate and acquired immune systems. The two collagenous lectins, mannose-binding lectin (MBL) and ficolins, are one of the pattern recognition molecules acting in innate immunity and upon recognition of the pathogens, they trigger the activation of the lectin complement pathway through attached serine proteases (MASPs). A similar lectin-base complement system, consisting of the lectin-protease complex and C3, is present in ascidians, our closest invertebrate relatives and functions in an opsonic manner. On the other hand, ongoing genome projects in both vertebrates and invertebrates revealed that most domains used by mammalian complement components are found in both protostomes and deuterostomes. However, the unique combinations of them as found in mammalian complement components are present only in deuterostomes, indicating the deuterostome origin of the complement system. Unexpectedly, the complement system of an invertebrate deuterostome, ascidian, shows a similar level of complexity as that of mammals, suggesting that expansion of complement genes by gene duplications occurred independently both in the ascidian and vertebrate lineages. Although most characteristic domain structures of the mammalian complement components are found in ascidians, detailed evolutionary analysis casts doubt on their mutual reactivity in several points. Thus, another integrative step seems to have been required to establish the modern complement system of higher vertebrates.
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Affiliation(s)
- Teizo Fujita
- Department of Biochemistry, Fukushima Medical University, and CREST, Japan Science and Technology Agency, Japan.
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32
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Fujita T, Matsushita M, Endo Y. The lectin-complement pathway--its role in innate immunity and evolution. Immunol Rev 2004; 198:185-202. [PMID: 15199963 DOI: 10.1111/j.0105-2896.2004.0123.x] [Citation(s) in RCA: 418] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Innate immunity was formerly thought to be a non-specific immune response characterized by phagocytosis. However, innate immunity has considerable specificity and is capable of discriminating between pathogens and self. Recognition of pathogens is mediated by a set of pattern recognition receptors, which recognize conserved pathogen-associated molecular patterns (PAMPs) shared by broad classes of microorganisms, thereby successfully defending invertebrates and vertebrates against infection. Lectins, carbohydrate-binding proteins, play an important role in innate immunity by recognizing a wide range of pathogens. Mannose-binding lectin (MBL) and ficolin are lectins composed of a lectin domain attached to collagenous region. However, they use a different lectin domain: a carbohydrate recognition domain (CRD) is responsible for MBL and a fibrinogen-like domain for ficolin. These two collagenous lectins are pattern recognition receptors, and upon recognition of the infectious agent, they trigger the activation of the lectin-complement pathway through attached serine proteases, MBL-associated serine proteases (MASPs). A similar lectin-based complement system, consisting of the lectin-protease complex and C3, is present in ascidians, our closest invertebrate relatives, and functions in an opsonic manner. We isolated several lectins homologous to MBLs and ficolins and several MASPs in invertebrates and lower vertebrates, and herein we discuss the molecular evolution of these molecules. Based on these findings, it seems likely that the complement system played a pivotal role in innate immunity before the evolution of an acquired immune system in jawed vertebrates.
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Affiliation(s)
- Teizo Fujita
- Department of Biochemistry, Fukushima Medical University, Fukushima, Japan.
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Tischenko VM, Zav'yalova GA, Bliznyukov OP, Zav'yalov VP. Thermodynamic, conformational and functional properties of the human C1q globular heads in the intact C1q molecule in solution. Mol Immunol 2004; 40:1225-36. [PMID: 15128039 DOI: 10.1016/j.molimm.2003.11.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Thermodynamic. conformational and functional properties of the human C1q globular heads (hgC1q) were studied with the experimental approaches, which allow investigating these properties in the intact hC1q molecule in solution. Surprisingly, the scanning calorimetry data reveal a low level of cooperativity of interactions between the hgC1q A, B and C domains even at a neutral pH area. Ionization of His residues due to acidification of the medium at the pH range from 6 to 5 or the chemical modification of His residues completely abolishes the cooperative interactions between the domains without significant effect on their conformation. The thermodynamic data provide evidence that the hgC1q module is composed of three structurally independent A, B and C globular domains characterized by the practically identical thermal stability and very similar enthalpy of melting. The spectroscopic studies and modification with 2-oxy-5-nitrobenzylbromide (ONBB) indicate that Trp residues in the hgC1q A and C domains are accessible to the solvent that has been confirmed by the hgC1q crystal structure solved and refined to 1.9 A. The modification of Trp residues significantly affects the complement-dependent cytotoxicity without noticeable effect on the hC1q conformation. These data provide evidence that Trp residues are the components of immunoglobulin-binding sites both in the hgC1q A and C domains.
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Affiliation(s)
- V M Tischenko
- The National Center for Biodefense, George Mason University, 10900 University Blvd., MS 4F3 Manassas, VA 20110, USA
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