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Dahmani M, Zhu JC, Cook JH, Riley SP. Anaphylatoxin signaling activates macrophages to control intracellular Rickettsia proliferation. Microbiol Spectr 2023; 11:e0253823. [PMID: 37855623 PMCID: PMC10714731 DOI: 10.1128/spectrum.02538-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 09/11/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE Pathogenic Rickettsia species are extremely dangerous bacteria that grow within the cytoplasm of host mammalian cells. In most cases, these bacteria are able to overpower the host cell and grow within the protected environment of the cytoplasm. However, a dramatic conflict occurs when Rickettsia encounter innate immune cells; the bacteria can "win" by taking over the host, or the bacteria can "lose" if the host cell efficiently fights the infection. This manuscript examines how the immune complement system is able to detect the presence of Rickettsia and alert nearby cells. Byproducts of complement activation called anaphylatoxins are signals that "activate" innate immune cells to mount an aggressive defensive strategy. This study enhances our collective understanding of the innate immune reaction to intracellular bacteria and will contribute to future efforts at controlling these dangerous infections.
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Affiliation(s)
- Mustapha Dahmani
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
| | - Jinyi C. Zhu
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
| | - Jack H. Cook
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
| | - Sean P. Riley
- Department of Veterinary Medicine, University of Maryland-College Park, College Park, Maryland, USA
- Virginia-Maryland College of Veterinary Medicine, College Park, Maryland, USA
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2
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Yadav MK, Maharana J, Yadav R, Saha S, Sarma P, Soni C, Singh V, Saha S, Ganguly M, Li XX, Mohapatra S, Mishra S, Khant HA, Chami M, Woodruff TM, Banerjee R, Shukla AK, Gati C. Molecular basis of anaphylatoxin binding, activation, and signaling bias at complement receptors. Cell 2023; 186:4956-4973.e21. [PMID: 37852260 PMCID: PMC7615941 DOI: 10.1016/j.cell.2023.09.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 07/19/2023] [Accepted: 09/20/2023] [Indexed: 10/20/2023]
Abstract
The complement system is a critical part of our innate immune response, and the terminal products of this cascade, anaphylatoxins C3a and C5a, exert their physiological and pathophysiological responses primarily via two GPCRs, C3aR and C5aR1. However, the molecular mechanism of ligand recognition, activation, and signaling bias of these receptors remains mostly elusive. Here, we present nine cryo-EM structures of C3aR and C5aR1 activated by their natural and synthetic agonists, which reveal distinct binding pocket topologies of complement anaphylatoxins and provide key insights into receptor activation and transducer coupling. We also uncover the structural basis of a naturally occurring mechanism to dampen the inflammatory response of C5a via proteolytic cleavage of the terminal arginine and the G-protein signaling bias elicited by a peptide agonist of C3aR identified here. In summary, our study elucidates the innerworkings of the complement anaphylatoxin receptors and should facilitate structure-guided drug discovery to target these receptors in a spectrum of disorders.
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Affiliation(s)
- Manish K Yadav
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Jagannath Maharana
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Ravi Yadav
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA; The Bridge Institute, Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA, USA
| | - Shirsha Saha
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Parishmita Sarma
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Chahat Soni
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Vinay Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Sayantan Saha
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Manisankar Ganguly
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Xaria X Li
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Samanwita Mohapatra
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Sudha Mishra
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Htet A Khant
- USC Center of Excellence for Nano-Imaging, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - Mohamed Chami
- BioEM Lab, Biozentrum, Universität Basel, Basel, Switzerland
| | - Trent M Woodruff
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ramanuj Banerjee
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.
| | - Arun K Shukla
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.
| | - Cornelius Gati
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA; The Bridge Institute, Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA, USA; Department of Chemistry, Department of Quantitative and Computational Biology, Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, USA.
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3
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Kareem S, Jacob A, Mathew J, Quigg RJ, Alexander JJ. Complement: Functions, location and implications. Immunology 2023; 170:180-192. [PMID: 37222083 PMCID: PMC10524990 DOI: 10.1111/imm.13663] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 05/09/2023] [Indexed: 05/25/2023] Open
Abstract
The complement system, an arm of the innate immune system plays a critical role in both health and disease. The complement system is highly complex with dual possibilities, helping or hurting the host, depending on the location and local microenvironment. The traditionally known functions of complement include surveillance, pathogen recognition, immune complex trafficking, processing and pathogen elimination. The noncanonical functions of the complement system include their roles in development, differentiation, local homeostasis and other cellular functions. Complement proteins are present in both, the plasma and on the membranes. Complement activation occurs both extra- and intracellularly, which leads to considerable pleiotropy in their activity. In order to design more desirable and effective therapies, it is important to understand the different functions of complement, and its location-based and tissue-specific responses. This manuscript will provide a brief overview into the complex nature of the complement cascade, outlining some of their complement-independent functions, their effects at different locale, and their implication in disease settings.
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Affiliation(s)
- Samer Kareem
- Department of Medicine, University at Buffalo, Buffalo, New York, United States
| | - Alexander Jacob
- Department of Medicine, University at Buffalo, Buffalo, New York, United States
| | - John Mathew
- Department of Rheumatology, Christian Medical College, Vellore, India
| | - Richard J Quigg
- Department of Medicine, University at Buffalo, Buffalo, New York, United States
| | - Jessy J Alexander
- Department of Medicine, University at Buffalo, Buffalo, New York, United States
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Holers VM. Complement therapeutics are coming of age in rheumatology. Nat Rev Rheumatol 2023; 19:470-485. [PMID: 37337038 DOI: 10.1038/s41584-023-00981-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2023] [Indexed: 06/21/2023]
Abstract
The complement system was described over 100 years ago, and it is well established that activation of this pathway accompanies the great majority of autoimmune and inflammatory diseases. In addition, over three decades of work in murine models of human disease have nearly universally demonstrated that complement activation is upstream of tissue injury and the engagement of pro-inflammatory mechanisms such as the elaboration of cytokines and chemokines, as well as myeloid cell recruitment and activation. With that background, and taking advantage of advances in the development of biologic and small-molecule therapeutics, the creation and clinical evaluation of complement therapeutics is now rapidly expanding. This article reviews the current state of the complement therapeutics field, with a focus on their use in diseases cared for or consulted upon by rheumatologists. Included is an overview of the activation mechanisms and components of the system, in addition to the mechanisms by which the complement system interacts with other immune system constituents. The various therapeutic approaches to modulating the system in rheumatic and autoimmune diseases are reviewed. To understand how best to clinically assess the complement system, methods of its evaluation are described. Finally, next-generation therapeutic and diagnostic advances that can be envisioned for the future are discussed.
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Affiliation(s)
- V Michael Holers
- Medicine/Rheumatology, University of Colorado School of Medicine, Aurora, CO, USA.
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Subramaniam S, Kothari H, Bosmann M. Tissue factor in COVID-19-associated coagulopathy. Thromb Res 2022; 220:35-47. [PMID: 36265412 PMCID: PMC9525243 DOI: 10.1016/j.thromres.2022.09.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/24/2022] [Accepted: 09/28/2022] [Indexed: 11/17/2022]
Abstract
Evidence of micro- and macro-thrombi in the arteries and veins of critically ill COVID-19 patients and in autopsies highlight the occurrence of COVID-19-associated coagulopathy (CAC). Clinical findings of critically ill COVID-19 patients point to various mechanisms for CAC; however, the definitive underlying cause is unclear. Multiple factors may contribute to the prothrombotic state in patients with COVID-19. Aberrant expression of tissue factor (TF), an initiator of the extrinsic coagulation pathway, leads to thrombotic complications during injury, inflammation, and infections. Clinical evidence suggests that TF-dependent coagulation activation likely plays a role in CAC. Multiple factors could trigger abnormal TF expression and coagulation activation in patients with severe COVID-19 infection. Proinflammatory cytokines that are highly elevated in COVID-19 (IL-1β, IL-6 and TNF-α) are known induce TF expression on leukocytes (e.g. monocytes, macrophages) and non-immune cells (e.g. endothelium, epithelium) in other conditions. Antiphospholipid antibodies, TF-positive extracellular vesicles, pattern recognition receptor (PRR) pathways and complement activation are all candidate factors that could trigger TF-dependent procoagulant activity. In addition, coagulation factors, such as thrombin, may further potentiate the induction of TF via protease-activated receptors on cells. In this systematic review, with other viral infections, we discuss potential mechanisms and cell-type-specific expressions of TF during SARS-CoV-2 infection and its role in the development of CAC.
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van Erp IAM, van Essen TA, Fluiter K, van Zwet E, van Vliet P, Baas F, Haitsma I, Verbaan D, Coert B, de Ruiter GCW, Moojen WA, van der Jagt M, Peul WC. Safety and efficacy of C1-inhibitor in traumatic brain injury (CIAO@TBI): study protocol for a randomized, placebo-controlled, multi-center trial. Trials 2021; 22:874. [PMID: 34863258 PMCID: PMC8642972 DOI: 10.1186/s13063-021-05833-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 11/15/2021] [Indexed: 01/21/2023] Open
Abstract
Background Traumatic brain injury (TBI) is a major cause of death and disability across all ages. After the primary impact, the pathophysiologic process of secondary brain injury consists of a neuroinflammation response that critically leads to irreversible brain damage in the first days after the trauma. A key catalyst in this inflammatory process is the complement system. Inhibiting the complement system could therefore be a therapeutic target in TBI. Objective To study the safety and efficacy of C1-inhibitor (C1-INH) compared to placebo in patients with TBI. By temporarily blocking the complement system, we hypothesize a decrease in the posttraumatic neuroinflammatory response resulting in a less unfavorable clinical outcome for TBI patients. Methods CIAO@TBI is a multicenter, randomized, blinded, phase II placebo-controlled trial. Adult TBI patients with GCS < 13 requiring intracranial pressure (ICP) monitoring will be randomized, using block randomization, within 12 h after trauma to one dose 6000 IU C1-INH or placebo. A total of 106 patients will be included, and follow-up will occur up to 12 months. The primary endpoints are (1) Therapy Intensity Level (TIL) Scale, (2) Glasgow Outcome Scale-Extended (GOSE) at 6 months, and (3) complication rate during hospitalization. Outcomes will be determined by a trial nurse blinded for the treatment allocation. Analyses will be conducted in an intention-to-treat analysis. Discussion We expect that C1-INH administration will be safe and potentially effective to improve clinical outcomes by reducing neuroinflammation in TBI patients. Trial registration ClinicalTrials.gov NCT04489160. Registered on 27 July 2020. EudraCT 2020-000140-58 Supplementary Information The online version contains supplementary material available at 10.1186/s13063-021-05833-1.
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Affiliation(s)
- Inge A M van Erp
- University Neurosurgical Center Holland, Leiden University Medical Center, Haaglanden Medical Center and Haga Teaching Hospital, Albinusdreef 2, J-11-R-83, 2333 ZA, Leiden, Hague, The Netherlands.
| | - Thomas A van Essen
- University Neurosurgical Center Holland, Leiden University Medical Center, Haaglanden Medical Center and Haga Teaching Hospital, Albinusdreef 2, J-11-R-83, 2333 ZA, Leiden, Hague, The Netherlands
| | - Kees Fluiter
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Erik van Zwet
- Department of Biomedical Data Science, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter van Vliet
- Department of Intensive Care, Haaglanden Medical Center, The Hague, The Netherlands
| | - Frank Baas
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Iain Haitsma
- Department of Neurosurgery, Erasmus MC - University Medical Center, Rotterdam, The Netherlands
| | - Dagmar Verbaan
- Neurosurgical Center Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Bert Coert
- Neurosurgical Center Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Godard C W de Ruiter
- University Neurosurgical Center Holland, Leiden University Medical Center, Haaglanden Medical Center and Haga Teaching Hospital, Albinusdreef 2, J-11-R-83, 2333 ZA, Leiden, Hague, The Netherlands
| | - Wouter A Moojen
- University Neurosurgical Center Holland, Leiden University Medical Center, Haaglanden Medical Center and Haga Teaching Hospital, Albinusdreef 2, J-11-R-83, 2333 ZA, Leiden, Hague, The Netherlands
| | - Mathieu van der Jagt
- Department of Intensive Care Adults, Erasmus MC - University Medical Center, Rotterdam, The Netherlands
| | - Wilco C Peul
- University Neurosurgical Center Holland, Leiden University Medical Center, Haaglanden Medical Center and Haga Teaching Hospital, Albinusdreef 2, J-11-R-83, 2333 ZA, Leiden, Hague, The Netherlands
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7
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Silawal S, Kohl B, Girke G, Schneider T, Schulze-Tanzil G. Complement regulation in tenocytes under the influence of leukocytes in an indirect co-culture model. Inflamm Res 2021; 70:495-507. [PMID: 33772629 DOI: 10.1007/s00011-021-01451-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 12/31/2019] [Accepted: 01/09/2020] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION The present in vitro study was undertaken to learn about the effects of leukocytes on tenocytes in respect to complement regulation simulating an inflammatory scenario of the traumatized tissue. METHODS Human hamstring tendon-derived tenocyte monolayers were co-cultured indirectly with human leukocytes (either Peripheral Blood Mononuclear Cells [PBMCs] or neutrophils) using a transwell system with/without (+ /wo) 10 ng/ml tumor necrosis factor α (TNFα) for 4 and 24 h. Tenocyte and leukocyte cell survival was assessed by live-dead assay. Tenocyte gene expression of TNFα, the anaphylatoxin receptor C5aR and the cytoprotective complement regulatory proteins (CRP) CD46, CD55 and CD59 was monitored using qPCR. TNFα was detected in the culture supernatants using ELISA. RESULTS C5aR gene expression was significantly induced by TNFα after 4 h, but impaired in the presence of leukocytes + TNFα after 24 h. At 4 h, PBMCs activated by TNFα induced the CRP CD46 gene expression. However, CD55 was significantly suppressed after 24 h by neutrophils + /woTNFα. Leukocytes activated by TNFα decreased also significantly the gene expression of the more downstream acting CRP CD59 after 4 h. TNFα gene expression and ELISA analysis revealed an amplified TNFα expression/release in tenocyte co-cultures with PBMC + /woTNFα, probably contributing to complement regulation. CONCLUSION TNFα might represent a crucial soluble mediator exerting diverse time-dependent effects on tenocyte complement regulation.
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Affiliation(s)
- Sandeep Silawal
- Institute of Anatomy and Cell Biology, Paracelsus Private Medical University, Nuremberg and Salzburg, General Hospital Nuremberg, Prof. Ernst Nathan Str. 1, 90419, Nuremberg, Germany
| | - Benjamin Kohl
- Department of Traumatology and Reconstructive Surgery, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin and Berlin Institute of Health, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany
| | - Georg Girke
- Department of Traumatology and Reconstructive Surgery, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin and Berlin Institute of Health, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany.,Department of Cardiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany
| | - Tobias Schneider
- Institute of Anatomy and Cell Biology, Paracelsus Private Medical University, Nuremberg and Salzburg, General Hospital Nuremberg, Prof. Ernst Nathan Str. 1, 90419, Nuremberg, Germany.,Department of Traumatology and Reconstructive Surgery, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin and Berlin Institute of Health, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany
| | - Gundula Schulze-Tanzil
- Institute of Anatomy and Cell Biology, Paracelsus Private Medical University, Nuremberg and Salzburg, General Hospital Nuremberg, Prof. Ernst Nathan Str. 1, 90419, Nuremberg, Germany.
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Tung ML, Tan B, Cherian R, Chandra B. Anti-phospholipid syndrome and COVID-19 thrombosis: connecting the dots. Rheumatol Adv Pract 2021; 5:rkaa081. [PMID: 33615129 PMCID: PMC7882149 DOI: 10.1093/rap/rkaa081] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/02/2020] [Indexed: 02/06/2023] Open
Abstract
As the coronavirus disease 2019 (COVID-19) pandemic, which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading rapidly worldwide, it has emerged as a leading cause of mortality, resulting in >1 million deaths over the past 10 months. The pathophysiology of COVID-19 remains unclear, posing a great challenge to the medical management of patients. Recent studies have reported an unusually high prevalence of thromboembolic events in COVID-19 patients, although the mechanism remains elusive. Several studies have reported the presence of aPLs in COVID-19 patients. We have noticed similarities between COVID-19 and APS, which is an autoimmune prothrombotic disease that is often associated with an infective aetiology. Molecular mimicry and endothelial dysfunction could plausibly explain the mechanism of thrombogenesis in acquired APS. In this review, we discuss the clinicopathological similarities between COVID-19 and APS, and the potential role of therapeutic targets based on the anti-phospholipid model for COVID-19 disease.
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Affiliation(s)
- Moon Ley Tung
- Department of Hematology and Oncology, National University Cancer Institute
- Yong Loo Lin School of Medicine, National University of Singapore
| | - Bryce Tan
- Department of Medicine, National University Hospital
| | - Robin Cherian
- Yong Loo Lin School of Medicine, National University of Singapore
- Department of Cardiology, National University Heart Centre Singapore
| | - Bharatendu Chandra
- Yong Loo Lin School of Medicine, National University of Singapore
- Division of Neurology, Department of Medicine, National University Hospital, Singapore, Singapore
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Insights into the Complement System of Tunicates: C3a/C5aR of the Colonial Ascidian Botryllus schlosseri. BIOLOGY 2020; 9:biology9090263. [PMID: 32882947 PMCID: PMC7565592 DOI: 10.3390/biology9090263] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/20/2020] [Accepted: 08/30/2020] [Indexed: 01/15/2023]
Abstract
As an evolutionary ancient component of the metazoan immune defense toolkit, the complement system can modulate cells and humoral responses of both innate and (in jawed vertebrates) adaptive immunity. All the three known complement-activation pathways converge on the cleavage of C3 to C3a and C3b. The anaphylatoxin C3a behaves as a chemokine in inflammatory responses, whereas C3b exerts an opsonic role and, ultimately, can activate the lytic pathway. C3aR, one of the mammalian receptors for C3a, is a member of the G-protein-coupled receptor family sharing seven transmembrane alpha helixes. C3aR can act as a chemokine and recruit neutrophils, triggering degranulation and respiratory burst, which initiates an inflammatory reaction. Mining the transcriptome of the colonial ascidian Botryllus schlosseri, we identified a transcript showing homology with both mammalian C3aR and C5aR. The gene (bsc3/c5ar) is actively transcribed in morula cells, the circulating immunocyte triggering the inflammatory reactions in response to the recognition of nonself. Its transcription is modulated during the recurrent cycles of asexual reproduction known as blastogenetic cycles. Moreover, the treatment of hemocytes with C3aR agonist, induces a significant increase in the transcription of BsC3, revealing the presence of an autocrine feedback system able to modulate the expression of C3 in order to obtain a rapid clearance of potentially dangerous nonself cells or particles. The obtained results support the previously proposed role of complement as one of the main humoral components of the immune response in tunicates and stress the importance of morula cells in botryllid ascidian innate immunity.
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Hua XT, Fan K, Zhang Z, Li X, Xia Y, Liu PF, Liu Y. Characterization and expression analysis of the C8α and C9 terminal complement components from pufferfish (Takifugu rubripes). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 106:103634. [PMID: 32004542 DOI: 10.1016/j.dci.2020.103634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/22/2020] [Accepted: 01/22/2020] [Indexed: 06/10/2023]
Abstract
C8α and C9 mediate the membrane attack complex formation and bacterial lysis and are important components in the complement system. The cDNA sequences of the C8α and C9 genes were cloned from Takifugu rubripes. The full-length cDNA of Tr-C8α was 1893 bp and included a 5'-UTR of 69 bp and 3'-UTR of 83 bp. The full-length cDNA of Tr-C9 was 2083 bp and included a 5'-UTR of 72 bp and 3'-UTR of 250 bp. The expression of Tr-C8α and Tr-C9 was detected in newly fertilized eggs of T. rubripes. The expression of these two genes was at a higher level in the liver than in other tissues tested. After lipopolysaccharide (LPS) challenge, the gene expression of Tr-C8α and Tr-C9 increased more significantly in the liver. With these combined results, we further understood how Tr-C8α and Tr-C9 function in the innate immunity of pufferfish. Our findings could deepen the understanding of immune regulation in pufferfish.
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Affiliation(s)
- Xin-Tong Hua
- College of Fisheries and Life Science, Dalian Ocean University, Dalian, 116023, China; Key Laboratory of Environment Controlled Aquaculture (KLECA), Ministry of Education, 52 Heishijiao Street, Dalian, 116023, China
| | - Kunpeng Fan
- College of Fisheries and Life Science, Dalian Ocean University, Dalian, 116023, China; Key Laboratory of Environment Controlled Aquaculture (KLECA), Ministry of Education, 52 Heishijiao Street, Dalian, 116023, China
| | - Zhiqiang Zhang
- College of Fisheries and Life Science, Dalian Ocean University, Dalian, 116023, China; Key Laboratory of Environment Controlled Aquaculture (KLECA), Ministry of Education, 52 Heishijiao Street, Dalian, 116023, China
| | - Xiaohao Li
- Key Laboratory of Environment Controlled Aquaculture (KLECA), Ministry of Education, 52 Heishijiao Street, Dalian, 116023, China; College of Marine Technology and Environment, Dalian Ocean University, Dalian, 116023, China
| | - Yuqing Xia
- Key Laboratory of Environment Controlled Aquaculture (KLECA), Ministry of Education, 52 Heishijiao Street, Dalian, 116023, China; College of Marine Technology and Environment, Dalian Ocean University, Dalian, 116023, China
| | - Peng-Fei Liu
- Key Laboratory of Environment Controlled Aquaculture (KLECA), Ministry of Education, 52 Heishijiao Street, Dalian, 116023, China; College of Marine Technology and Environment, Dalian Ocean University, Dalian, 116023, China; Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266071, China.
| | - Ying Liu
- Key Laboratory of Environment Controlled Aquaculture (KLECA), Ministry of Education, 52 Heishijiao Street, Dalian, 116023, China; College of Marine Technology and Environment, Dalian Ocean University, Dalian, 116023, China; Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266071, China.
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11
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Shivshankar P, Li YD, Mueller-Ortiz SL, Wetsel RA. In response to complement anaphylatoxin peptides C3a and C5a, human vascular endothelial cells migrate and mediate the activation of B-cells and polarization of T-cells. FASEB J 2020; 34:7540-7560. [PMID: 32301538 DOI: 10.1096/fj.201902397r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 03/11/2020] [Accepted: 03/22/2020] [Indexed: 12/19/2022]
Abstract
The vascular endothelium has been discovered in the past several years to be important in shaping the cellular immune response. During the immune response the vascular endothelium is constantly perturbed by biologically potent molecules, including the complement activation peptides, C3a and C5a. Despite the importance of C3a and C5a in inflammation and immunity, their role in modulating lymphocyte function via activation of vascular endothelial cells is unknown. Accordingly, we investigated the regulated expression of the C3a and C5a receptors (complement anaphylatoxin C3a receptor [C3aR] and complement anaphylatoxin C5a receptor 1 [C5aR1]) on human umbilical vascular endothelial cells (HUVECs) and examined how C3a or C5a activation of HUVECs affects the activation and polarization of lymphatic cells. Our findings demonstrated that C3a and C5a increase C3aR and C5aR1 expression by HUVECs as well as directing their cellular transmigration and spreading through transwell filters. Moreover, C3a- or C5a-stimulated endothelial cells: (1) caused activation of B-lymphoblasts with significant increase in Fas Ligand (CD95L) (FasL), CD69, and IL-R1 expression, and (2) skewed T-lymphoblast cells toward a Th1 subtype, (CD4+ /CCR5+ ) that correlated with significant increase of IFN-γ. Collectively, these data indicate that C3a and C5a signaling is important in the activation and polarization of lymphocytes as they traffic through the vascular endothelium during the immune response.
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Affiliation(s)
- Pooja Shivshankar
- Research Center for Immunology and Autoimmune Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - Yi-Dong Li
- Research Center for Immunology and Autoimmune Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - Stacey L Mueller-Ortiz
- Research Center for Immunology and Autoimmune Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - Rick A Wetsel
- Research Center for Immunology and Autoimmune Diseases, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA.,Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
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12
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Zelek WM, Xie L, Morgan BP, Harris CL. Compendium of current complement therapeutics. Mol Immunol 2019; 114:341-352. [PMID: 31446305 DOI: 10.1016/j.molimm.2019.07.030] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/29/2019] [Accepted: 07/29/2019] [Indexed: 12/13/2022]
Abstract
The complement system is well known for its role in innate immunity and in maintenance of tissue homeostasis, providing a first line of defence against infection and playing a key role in flagging apoptotic cells and debris for disposal. Unfortunately, complement also contributes to pathogenesis of many diseases, in some cases driving pathology, and in others amplifying or exacerbating the inflammatory and damaging impact of non-complement disease triggers. The driving role of complement in a single disease, paroxysmal nocturnal hemoglobinuria (PNH), provoked the development and eventual FDA (US Food and Drug Administration) approval of eculizumab (Soliris™), an anti-C5 antibody, for therapy. Although PNH is very rare, eculizumab provided clinical validation and demonstrated that inhibiting the complement system was not only well-tolerated, but also provided rapid therapy and saved lives. This clinical validation, together with advances in genetic analyses that demonstrated strong associations between complement and common diseases, drove new drug discovery programmes in both academic laboratories and large pharmaceutical companies. Numerous drugs have entered clinical development and several are in phase 3 trials; however, many have fallen by the wayside. Despite this high attrition rate, crucial lessons have been learnt and hurdles to development have become clear. These insights have driven development of next generation anti-complement drugs designed to avoid pitfalls and facilitate patient access. In this article, we do not set out to provide a text-heavy review of complement therapeutics but instead will simply highlight the targets, modalities and current status of the plethora of drugs approved or in clinical development. With such a fast-moving drug development landscape, such a compendium will inevitably become out-dated; however, we provide a snapshot of the current field and illustrate the increased choice that clinicians might enjoy in the future in selecting the best drug for their application, decisions based not only on efficacy but also cost, mechanistic target, modality and route of delivery.
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Affiliation(s)
- Wioleta M Zelek
- Systems Immunity Research Institute and Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK
| | - Long Xie
- Complement Therapeutics Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - B Paul Morgan
- Systems Immunity Research Institute and Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, CF14 4XN, UK
| | - Claire L Harris
- Complement Therapeutics Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK; National Renal Complement Therapeutics Centre, Building 26, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, UK.
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13
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Ma Y, Liu Y, Zhang Z, Yang GY. Significance of Complement System in Ischemic Stroke: A Comprehensive Review. Aging Dis 2019; 10:429-462. [PMID: 31011487 PMCID: PMC6457046 DOI: 10.14336/ad.2019.0119] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/19/2019] [Indexed: 12/14/2022] Open
Abstract
The complement system is an essential part of innate immunity, typically conferring protection via eliminating pathogens and accumulating debris. However, the defensive function of the complement system can exacerbate immune, inflammatory, and degenerative responses in various pathological conditions. Cumulative evidence indicates that the complement system plays a critical role in the pathogenesis of ischemic brain injury, as the depletion of certain complement components or the inhibition of complement activation could reduce ischemic brain injury. Although multiple candidates modulating or inhibiting complement activation show massive potential for the treatment of ischemic stroke, the clinical availability of complement inhibitors remains limited. The complement system is also involved in neural plasticity and neurogenesis during cerebral ischemia. Thus, unexpected side effects could be induced if the systemic complement system is inhibited. In this review, we highlighted the recent concepts and discoveries of the roles of different kinds of complement components, such as C3a, C5a, and their receptors, in both normal brain physiology and the pathophysiology of brain ischemia. In addition, we comprehensively reviewed the current development of complement-targeted therapy for ischemic stroke and discussed the challenges of bringing these therapies into the clinic. The design of future experiments was also discussed to better characterize the role of complement in both tissue injury and recovery after cerebral ischemia. More studies are needed to elucidate the molecular and cellular mechanisms of how complement components exert their functions in different stages of ischemic stroke to optimize the intervention of targeting the complement system.
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Affiliation(s)
- Yuanyuan Ma
- 1Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yanqun Liu
- 3Department of Neurology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Zhijun Zhang
- 2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Guo-Yuan Yang
- 1Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
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14
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Liyanage DS, Omeka WKM, Godahewa GI, Lee S, Nam BH, Lee J. Membrane attack complex-associated molecules from redlip mullet (Liza haematocheila): Molecular characterization and transcriptional evidence of C6, C7, C8β, and C9 in innate immunity. FISH & SHELLFISH IMMUNOLOGY 2018; 81:1-9. [PMID: 29981471 DOI: 10.1016/j.fsi.2018.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/25/2018] [Accepted: 07/04/2018] [Indexed: 06/08/2023]
Abstract
The redlip mullet (Liza haematocheila) is one of the most economically important fish in Korea and other East Asian countries; it is susceptible to infections by pathogens such as Lactococcus garvieae, Argulus spp., Trichodina spp., and Vibrio spp. Learning about the mechanisms of the complement system of the innate immunity of redlip mullet is important for efforts towards eradicating pathogens. Here, we report a comprehensive study of the terminal complement complex (TCC) components that form the membrane attack complex (MAC) through in-silico characterization and comparative spatial and temporal expression profiling. Five conserved domains (TSP1, LDLa, MACPF, CCP, and FIMAC) were detected in the TCC components, but the CCP and FIMAC domains were absent in MuC8β and MuC9. Expression analysis of four TCC genes from healthy redlip mullets showed the highest expression levels in the liver, whereas limited expression was observed in other tissues; immune-induced expression in the head kidney and spleen revealed significant responses against Lactococcus garvieae and poly I:C injection, suggesting their involvement in MAC formation in response to harmful pathogenic infections. Furthermore, the response to poly I:C may suggest the role of TCC components in the breakdown of the membrane of enveloped viruses. These findings may help to elucidate the mechanisms behind the complement system of the teleosts innate immunity.
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Affiliation(s)
- D S Liyanage
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea
| | - W K M Omeka
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea
| | - G I Godahewa
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea
| | - Seongdo Lee
- 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.
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15
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Reichhardt MP, Meri S. Intracellular complement activation-An alarm raising mechanism? Semin Immunol 2018; 38:54-62. [PMID: 29631809 DOI: 10.1016/j.smim.2018.03.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/26/2018] [Indexed: 12/20/2022]
Abstract
It has become increasingly apparent that the complement system, being an ancient defense mechanism, is not operative only in the extracellular milieu but also intracellularly. In addition to the known synthetic machinery in the liver and by macrophages, many other cell types, including lymphocytes, adipocytes and epithelial cells produce selected complement components. Activation of e.g. C3 and C5 inside cells may have multiple effects ranging from direct antimicrobial defense to cell differentiation and possible influence on metabolism. Intracellular activation of C3 and C5 in T cells is involved in the maintenance of immunological tolerance and promotes differentiation of T helper cells into Th1-type cells that activate cell-mediated immune responses. Adipocytes are unique in producing many complement sensor proteins (like C1q) and Factor D (adipsin), the key enzyme in promoting alternative pathway amplification. The effects of complement activation products are mediated by intracellular and cell membrane receptors, like C3aR, C5aR1, C5aR2 and the complement regulator MCP/CD46, often jointly with other receptors like the T cell receptor, Toll-like receptors and those of the inflammasomes. These recent observations link complement activation to cellular metabolic processes, intracellular defense reactions and to diverse adaptive immune responses. The complement components may thus be viewed as intracellular alarm molecules involved in the cellular danger response.
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Affiliation(s)
- M P Reichhardt
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom.
| | - S Meri
- Department of Bacteriology and Immunology, Haartman Institute, Immunobiology Research Program, University of Helsinki, Helsinki, Finland; Helsinki University Central Hospital Laboratory (HUSLAB), Helsinki, Finland.
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16
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Szebeni J. Mechanism of nanoparticle-induced hypersensitivity in pigs: complement or not complement? Drug Discov Today 2018; 23:487-492. [DOI: 10.1016/j.drudis.2018.01.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 11/09/2017] [Accepted: 01/04/2018] [Indexed: 02/01/2023]
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17
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Pandey MK, Grabowski GA, Köhl J. An unexpected player in Gaucher disease: The multiple roles of complement in disease development. Semin Immunol 2018; 37:30-42. [PMID: 29478824 DOI: 10.1016/j.smim.2018.02.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/15/2018] [Accepted: 02/16/2018] [Indexed: 12/14/2022]
Abstract
The complement system is well appreciated for its role as an important effector of innate immunity that is activated by the classical, lectin or alternative pathway. C5a is one important mediator of the system that is generated in response to canonical and non-canonical C5 cleavage by circulating or cell-derived proteases. In addition to its function as a chemoattractant for neutrophils and other myeloid effectors, C5a and its sister molecule C3a have concerted roles in cell homeostasis and surveillance. Through activation of their cognate G protein coupled receptors, C3a and C5a regulate multiple intracellular pathways within the mitochondria and the lysosomal compartments that harbor multiple enzymes critical for protein, carbohydrate and lipid metabolism. Genetic mutations of such lysosomal enzymes or their receptors can result in the compartmental accumulation of specific classes of substrates in this organelle summarized as lysosomal storage diseases (LSD). A frequent LSD is Gaucher disease (GD), caused by autosomal recessively inherited mutations in GBA1, resulting in functional defects of the encoded enzyme, acid β-glucosidase (glucocerebrosidase, GCase). Such mutations promote excessive accumulation of β-glucosylceramide (GC or GL1) in innate and adaptive immune cells frequently associated with chronic inflammation. Recently, we uncovered an unexpected link between the C5a and C5a receptor 1 (C5aR1) axis and the accumulation of GL1 in experimental and clinical GD. Here, we will review the pathways of complement activation in GD, its role as a mediator of the inflammatory response, and its impact on glucosphingolipid metabolism. Further, we will discuss the potential role of the C5a/C5aR1 axis in GL1-specific autoantibody formation and as a novel therapeutic target in GD.
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Affiliation(s)
- Manoj K Pandey
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA; The Department of Pediatrics of the University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA.
| | - Gregory A Grabowski
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA; The Department of Pediatrics of the University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA
| | - Jörg Köhl
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA; The Department of Pediatrics of the University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA; Institute for Systemic Inflammation Research, University of Lübeck, 23562, Lübeck, Germany.
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18
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Thurman JM, Frazer-Abel A, Holers VM. The Evolving Landscape for Complement Therapeutics in Rheumatic and Autoimmune Diseases. Arthritis Rheumatol 2017; 69:2102-2113. [PMID: 28732131 PMCID: PMC5659941 DOI: 10.1002/art.40219] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 07/18/2017] [Indexed: 12/13/2022]
Abstract
The complement system is increasingly understood to play major roles in the pathogenesis of human inflammatory and autoimmune diseases. Because of this situation, there are rapidly expanding commercial efforts to develop novel complement inhibitors and effector pathway-modulating drugs. This review provides insights into the evolving understanding of the complement system components, mechanisms of activation within and across the 3 pathways (classical, alternative, and lectin), how the pathways are normally controlled and then dysregulated in target tissues, and what diseases are known to be, in large part, complement-dependent through the successful development and approval of complement therapeutics in patients. Mechanisms of complement activation in rheumatoid arthritis, lupus, and thrombotic microangiopathies are also illustrated. In addition, the specific therapeutic drugs that are both approved and under development are discussed in the context of both nonrheumatic and rheumatic diseases. Finally, the methods by which the complement system can be assessed in humans through biomarker studies are outlined, with the goal of understanding, in specific patients, how the system is functioning.
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Affiliation(s)
- Joshua M. Thurman
- University of Colorado Denver, Division of Nephrology and Hypertension, Aurora, CO, USA
| | - Ashley Frazer-Abel
- University of Colorado Denver, Division of Rheumatology, Aurora, CO, USA
- Exsera BioLabs, University of Colorado Denver, Aurora, CO, USA
| | - V. Michael Holers
- University of Colorado Denver, Division of Rheumatology, Aurora, CO, USA
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19
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Reichhardt M, Holmskov U, Meri S. SALSA—A dance on a slippery floor with changing partners. Mol Immunol 2017; 89:100-110. [DOI: 10.1016/j.molimm.2017.05.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 05/31/2017] [Accepted: 05/31/2017] [Indexed: 02/06/2023]
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20
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Antiphospholipid Syndrome: Role of Vascular Endothelial Cells and Implications for Risk Stratification and Targeted Therapeutics. J Am Coll Cardiol 2017; 69:2317-2330. [PMID: 28473138 DOI: 10.1016/j.jacc.2017.02.058] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 02/21/2017] [Accepted: 02/28/2017] [Indexed: 12/28/2022]
Abstract
Antiphospholipid syndrome (APS) is an autoimmune disease characterized by venous thromboembolism, arterial thrombosis, and obstetric morbidities in the setting of persistently positive levels of antiphospholipid antibodies measured on 2 different occasions 12 weeks apart. Patients with APS are at increased risk for accelerated atherosclerosis, myocardial infarction, stroke, and valvular heart disease. Vascular endothelial cell dysfunction mediated by antiphospholipid antibodies and subsequent complement system activation play a cardinal role in APS pathogenesis. Improved understanding of their pathogenic function could help in the risk stratification of patients with APS and provide new molecular therapeutic targets.
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21
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Lubbers R, van Essen MF, van Kooten C, Trouw LA. Production of complement components by cells of the immune system. Clin Exp Immunol 2017; 188:183-194. [PMID: 28249350 DOI: 10.1111/cei.12952] [Citation(s) in RCA: 299] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2017] [Indexed: 12/14/2022] Open
Abstract
The complement system is an important part of the innate immune defence. It contributes not only to local inflammation, removal and killing of pathogens, but it also assists in shaping of the adaptive immune response. Besides a role in inflammation, complement is also involved in physiological processes such as waste disposal and developmental programmes. The complement system comprises several soluble and membrane-bound proteins. The bulk of the soluble proteins is produced mainly by the liver. While several complement proteins are produced by a wide variety of cell types, other complement proteins are produced by only a few related cell types. As these data suggest that local production by specific cell types may have specific functions, more detailed studies have been employed recently analysing the local and even intracellular role of these complement proteins. Here we review the current knowledge about extrahepatic production and/or secretion of complement components. More specifically, we address what is known about complement synthesis by cells of the human immune system.
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Affiliation(s)
- R Lubbers
- Department of Rheumatology, Leiden University Medical Center, Leiden, the Netherlands
| | - M F van Essen
- Department of Nephrology, Leiden University Medical Center, Leiden, the Netherlands
| | - C van Kooten
- Department of Nephrology, Leiden University Medical Center, Leiden, the Netherlands
| | - L A Trouw
- Department of Rheumatology, Leiden University Medical Center, Leiden, the Netherlands
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22
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Antić-Stanković J, Stanković S. THE COMPLEMENT SYSTEM: PATHWAYS OF ACTIVATIONS AND FUNCTION. ACTA MEDICA MEDIANAE 2017. [DOI: 10.5633/amm.2017.0108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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23
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Granados-Durán P, López-Ávalos MD, Cifuentes M, Pérez-Martín M, Fernández-Arjona MDM, Hughes TR, Johnson K, Morgan BP, Fernández-Llebrez P, Grondona JM. Microbial Neuraminidase Induces a Moderate and Transient Myelin Vacuolation Independent of Complement System Activation. Front Neurol 2017; 8:78. [PMID: 28326060 PMCID: PMC5339270 DOI: 10.3389/fneur.2017.00078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/20/2017] [Indexed: 02/05/2023] Open
Abstract
AIMS Some central nervous system pathogens express neuraminidase (NA) on their surfaces. In the rat brain, a single intracerebroventricular (ICV) injection of NA induces myelin vacuolation in axonal tracts. Here, we explore the nature, the time course, and the role of the complement system in this damage. METHODS The spatiotemporal analysis of myelin vacuolation was performed by optical and electron microscopy. Myelin basic protein-positive area and oligodendrocyte transcription factor (Olig2)-positive cells were quantified in the damaged bundles. Neuronal death in the affected axonal tracts was assessed by Fluoro-Jade B and anti-caspase-3 staining. To evaluate the role of the complement, membrane attack complex (MAC) deposition on damaged bundles was analyzed using anti-C5b9. Rats ICV injected with the anaphylatoxin C5a were studied for myelin damage. In addition, NA-induced vacuolation was studied in rats with different degrees of complement inhibition: normal rats treated with anti-C5-blocking antibody and C6-deficient rats. RESULTS The stria medullaris, the optic chiasm, and the fimbria were the most consistently damaged axonal tracts. Vacuolation peaked 7 days after NA injection and reverted by day 15. Olig2+ cell number in the damaged tracts was unaltered, and neurodegeneration associated with myelin alterations was not detected. MAC was absent on damaged axonal tracts, as revealed by C5b9 immunostaining. Rats ICV injected with the anaphylatoxin C5a displayed no myelin injury. When the complement system was experimentally or constitutively inhibited, NA-induced myelin vacuolation was similar to that observed in normal rats. CONCLUSION Microbial NA induces a moderate and transient myelin vacuolation that is not caused either by neuroinflammation or complement system activation.
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Affiliation(s)
- Pablo Granados-Durán
- Laboratorio de Fisiología Animal, Facultad de Ciencias, Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga , Málaga , Spain
| | - María Dolores López-Ávalos
- Laboratorio de Fisiología Animal, Facultad de Ciencias, Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga , Málaga , Spain
| | - Manuel Cifuentes
- Laboratorio de Fisiología Animal, Facultad de Ciencias, Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga, Málaga, Spain; Centro de Investigaciones Biomédicas en Red de Bioingeniería, Biomateriales y Nanomedicina, CIBER BBN, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Margarita Pérez-Martín
- Laboratorio de Fisiología Animal, Facultad de Ciencias, Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga , Málaga , Spain
| | - María Del Mar Fernández-Arjona
- Laboratorio de Fisiología Animal, Facultad de Ciencias, Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga , Málaga , Spain
| | - Timothy R Hughes
- Division of Infection and Immunity, School of Medicine, Cardiff University , Cardiff , UK
| | | | - B Paul Morgan
- Division of Infection and Immunity, School of Medicine, Cardiff University , Cardiff , UK
| | - Pedro Fernández-Llebrez
- Laboratorio de Fisiología Animal, Facultad de Ciencias, Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga , Málaga , Spain
| | - Jesús M Grondona
- Laboratorio de Fisiología Animal, Facultad de Ciencias, Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga , Málaga , Spain
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24
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Calame DG, Mueller-Ortiz SL, Wetsel RA. Innate and adaptive immunologic functions of complement in the host response to Listeria monocytogenes infection. Immunobiology 2016; 221:1407-1417. [PMID: 27476791 DOI: 10.1016/j.imbio.2016.07.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 06/15/2016] [Accepted: 07/13/2016] [Indexed: 12/20/2022]
Abstract
Listeria monocytogenes is a leading cause of foodborne-illness associated mortality that has attracted considerable attention in recent years due to several significant outbreaks. It has also served as a model organism for the study of intracellular pathogens. For these reasons the host response to L. monocytogenes has long been the subject of investigation. A potent innate and adaptive immune response is required for containment and clearance of L. monocytogenes. However, some elements of this response, such as type 1 interferons, can be detrimental to the host. Recent studies have revealed novel functions for the complement system, an ancient arm of innate immunity, in this process. Here we review the role of complement in the host response to L. monocytogenes.
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Affiliation(s)
- Daniel G Calame
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX 77030, United States; University of Texas McGovern Medical School at Houston, The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, United States
| | - Stacey L Mueller-Ortiz
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX 77030, United States
| | - Rick A Wetsel
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX 77030, United States; Department of Biochemistry and Molecular Biology, University of Texas McGovern Medical School at Houston, Houston, TX 77030, United States.
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25
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Holers VM, Tomlinson S, Kulik L, Atkinson C, Rohrer B, Banda N, Thurman JM. New therapeutic and diagnostic opportunities for injured tissue-specific targeting of complement inhibitors and imaging modalities. Semin Immunol 2016; 28:260-7. [PMID: 27282113 DOI: 10.1016/j.smim.2016.05.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/15/2016] [Accepted: 05/17/2016] [Indexed: 01/27/2023]
Abstract
Despite substantial opportunity and commercial interest in developing drugs that modulate the complement system in a broad range of non-orphan indications, several obstacles remain to be overcome. Among these issues is the biophysical nature of complement proteins, whose circulating levels are typically very high and whose turnover rates are relatively rapid, especially in the setting of chronic inflammatory conditions. This situation necessitates the use of very high levels of therapeutic compounds in order to achieve both multi-pathway and multiple effector mechanism inhibition. In addition, one must avoid infectious complications or the systemic impairment of the other important physiological functions of complement. Herein we focus on the development of a novel therapeutic strategy based on injured tissue-specific targeting of complement inhibitors using the antigen-combining domains of a small subset of natural IgM antibodies, which as endogenous antibodies specifically recognize sites of local damage across a broad range of tissues and locally activate complement C3, resulting in C3 fragment covalent fixation. Because the use of such recombinant tissue-targeting inhibitors precludes the utility of measuring systemic levels of complement biomarkers or function, since a goal of this targeting strategy is to leave those processes intact and unimpeded, we also briefly describe a new method designed to quantitatively measure using imaging modalities the inhibition of generation of fixed C3 fragments at sites of inflammation/injury. In addition to the ability to determine whether complement activation is locally constrained with the use of inhibitors, there is also a broader application of this imaging approach to inflammatory and autoimmune diseases characterized by local complement activation.
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Affiliation(s)
- V Michael Holers
- Departments of Medicine and Immunology, University of Colorado School of Medicine, Aurora, CO, United States.
| | - Stephen Tomlinson
- Research Service, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, United States; Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
| | - Liudmila Kulik
- Departments of Medicine and Immunology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Carl Atkinson
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States; Department of Surgery, Transplant Immunobiology Laboratory, Medical University of South Carolina, Charleston, SC, United States
| | - Bärbel Rohrer
- Research Service, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, United States; Department of Ophthalmology, Medical University of South Carolina, Charleston, SC, United States
| | - Nirmal Banda
- Departments of Medicine and Immunology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Joshua M Thurman
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, United States
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Zewde N, Gorham RD, Dorado A, Morikis D. Quantitative Modeling of the Alternative Pathway of the Complement System. PLoS One 2016; 11:e0152337. [PMID: 27031863 PMCID: PMC4816337 DOI: 10.1371/journal.pone.0152337] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 03/11/2016] [Indexed: 12/26/2022] Open
Abstract
The complement system is an integral part of innate immunity that detects and eliminates invading pathogens through a cascade of reactions. The destructive effects of the complement activation on host cells are inhibited through versatile regulators that are present in plasma and bound to membranes. Impairment in the capacity of these regulators to function in the proper manner results in autoimmune diseases. To better understand the delicate balance between complement activation and regulation, we have developed a comprehensive quantitative model of the alternative pathway. Our model incorporates a system of ordinary differential equations that describes the dynamics of the four steps of the alternative pathway under physiological conditions: (i) initiation (fluid phase), (ii) amplification (surfaces), (iii) termination (pathogen), and (iv) regulation (host cell and fluid phase). We have examined complement activation and regulation on different surfaces, using the cellular dimensions of a characteristic bacterium (E. coli) and host cell (human erythrocyte). In addition, we have incorporated neutrophil-secreted properdin into the model highlighting the cross talk of neutrophils with the alternative pathway in coordinating innate immunity. Our study yields a series of time-dependent response data for all alternative pathway proteins, fragments, and complexes. We demonstrate the robustness of alternative pathway on the surface of pathogens in which complement components were able to saturate the entire region in about 54 minutes, while occupying less than one percent on host cells at the same time period. Our model reveals that tight regulation of complement starts in fluid phase in which propagation of the alternative pathway was inhibited through the dismantlement of fluid phase convertases. Our model also depicts the intricate role that properdin released from neutrophils plays in initiating and propagating the alternative pathway during bacterial infection.
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Affiliation(s)
- Nehemiah Zewde
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
| | - Ronald D. Gorham
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
| | - Angel Dorado
- Department of Mechanical Engineering, University of California Riverside, Riverside, California, United States of America
| | - Dimitrios Morikis
- Department of Bioengineering, University of California Riverside, Riverside, California, United States of America
- * E-mail:
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Gelber SE, Brent E, Redecha P, Perino G, Tomlinson S, Davisson RL, Salmon JE. Prevention of Defective Placentation and Pregnancy Loss by Blocking Innate Immune Pathways in a Syngeneic Model of Placental Insufficiency. THE JOURNAL OF IMMUNOLOGY 2015; 195:1129-38. [PMID: 26071558 DOI: 10.4049/jimmunol.1402220] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 05/20/2015] [Indexed: 12/18/2022]
Abstract
Defective placentation and subsequent placental insufficiency lead to maternal and fetal adverse pregnancy outcome, but their pathologic mechanisms are unclear, and treatment remains elusive. The mildly hypertensive BPH/5 mouse recapitulates many features of human adverse pregnancy outcome, with pregnancies characterized by fetal loss, growth restriction, abnormal placental development, and defects in maternal decidual arteries. Using this model, we show that recruitment of neutrophils triggered by complement activation at the maternal/fetal interface leads to elevation in local TNF-α levels, reduction of the essential angiogenic factor vascular endothelial growth factor, and, ultimately, abnormal placentation and fetal death. Blockade of complement with inhibitors specifically targeted to sites of complement activation, depletion of neutrophils, or blockade of TNF-α improves spiral artery remodeling and rescues pregnancies. These data underscore the importance of innate immune system activation in the pathogenesis of placental insufficiency and identify novel methods for treatment of pregnancy loss mediated by abnormal placentation.
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Affiliation(s)
- Shari E Gelber
- Department of Obstetrics and Gynecology, Weill Cornell Medical Center, New York, NY 10065
| | - Elyssa Brent
- Department of Obstetrics and Gynecology, Weill Cornell Medical Center, New York, NY 10065
| | - Patricia Redecha
- Department of Medicine, Hospital for Special Surgery, Weill Cornell Medical Center, New York, NY 10021
| | - Giorgio Perino
- Department of Pathology and Laboratory Medicine, Hospital for Special Surgery, New York, NY 10021
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Darby Children's Research Institute, Medical University of South Carolina, Charleston, SC 29425; Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29401
| | - Robin L Davisson
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853; and Department of Cell and Developmental Biology, Weill Cornell Medical Center, New York, NY 10065
| | - Jane E Salmon
- Department of Medicine, Hospital for Special Surgery, Weill Cornell Medical Center, New York, NY 10021;
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Fearn A, Sheerin NS. Complement activation in progressive renal disease. World J Nephrol 2015; 4:31-40. [PMID: 25664245 PMCID: PMC4317626 DOI: 10.5527/wjn.v4.i1.31] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 11/14/2014] [Accepted: 12/10/2014] [Indexed: 02/06/2023] Open
Abstract
Chronic kidney disease (CKD) is common and the cause of significant morbidity and mortality. The replacement of functioning nephrons by fibrosis is characteristic of progressive disease. The pathways that lead to fibrosis are not fully understood, although chronic non-resolving inflammation in the kidney is likely to drive the fibrotic response that occurs. In patients with progressive CKD there is histological evidence of inflammation in the interstitium and strategies that reduce inflammation reduce renal injury in pre-clinical models of CKD. The complement system is an integral part of the innate immune system but also augments adaptive immune responses. Complement activation is known to occur in many diverse renal diseases, including glomerulonephritis, thrombotic microangiopathies and transplant rejection. In this review we discuss current evidence that complement activation contributes to progression of CKD, how complement could cause renal inflammation and whether complement inhibition would slow progression of renal disease.
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Abstract
Complement is traditionally known to be a system of serum proteins that provide protection against pathogens through direct cell lysis and the mobilization of innate and adaptive immunity. However, recent work indicates that the complement system has additional physiological roles beyond those in host defence. In this Opinion article, we describe the new modes and locations of complement activation that enable it to interact with other cell effector systems, such as growth factor receptors, inflammasomes and metabolic pathways. We propose that the location of complement activation dictates its function.
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30
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Szebeni J. Complement activation-related pseudoallergy: A stress reaction in blood triggered by nanomedicines and biologicals. Mol Immunol 2014; 61:163-73. [DOI: 10.1016/j.molimm.2014.06.038] [Citation(s) in RCA: 222] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 06/27/2014] [Accepted: 06/28/2014] [Indexed: 11/28/2022]
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31
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De Hoog VC, Timmers L, Van Duijvenvoorde A, De Jager SCA, Van Middelaar BJ, Smeets MB, Woodruff TM, Doevendans PA, Pasterkamp G, Hack CE, De Kleijn DPV. Leucocyte expression of complement C5a receptors exacerbates infarct size after myocardial reperfusion injury. Cardiovasc Res 2014; 103:521-9. [PMID: 24935433 DOI: 10.1093/cvr/cvu153] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIMS Early reperfusion is mandatory for the treatment of acute myocardial infarction. This process, however, also induces additional loss of viable myocardium, called ischaemia-reperfusion (IR) injury. Complement activation plays an important role in IR injury, partly through binding of C5a to its major receptor (C5aR). We investigated the role of C5aR on infarct size and cardiac function in a model for myocardial IR injury. METHODS AND RESULTS BALB/c (WT) mice and C5aR(-/-) mice underwent coronary occlusion for 30 min, followed by reperfusion. Infarct size, determined 24 h after IR, was reduced in C5aR(-/-) mice compared with WT mice (28.5 ± 2.1 vs. 35.7 ± 2.5%, P = 0.017). Bone marrow (BM) chimaera experiments showed that this effect was due to the absence of C5aR on circulating leucocytes, since a similar reduction in infarct size was observed in WT mice with C5aR-deficient BM cells (25.3 ± 2.2 vs. 34.6 ± 2.8%, P < 0.05), but not in C5aR(-/-) mice with WT BM cells. Reduced infarct size was associated with fewer neutrophils, T cells, and macrophages in the infarcted area 24 h after IR in C5aR(-/-) mice, and also with lower levels of Caspase-3/7 indicating less inflammation and apoptosis. Echocardiography 4 weeks after IR showed an improved ejection fraction in C5aR(-/-) mice (25.8 ± 5.5 vs. 19.2 ± 5.4%, P < 0.001). CONCLUSION The absence of C5aR on circulating leucocytes reduces infarct size, is associated with reduced leucocyte infiltration and with less apoptosis in the infarcted myocardium, and improves cardiac function in a mouse model of myocardial IR injury. Selective blocking of C5aR might be a promising strategy to prevent myocardial IR injury.
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Affiliation(s)
- Vince C De Hoog
- Laboratory of Experimental Cardiology, Department of Cardiology UMC Utrecht, University Medical Center Utrecht, Heidelberglaan 100, Room G02.523, Utrecht 3584 CX, The Netherlands
| | - Leo Timmers
- Laboratory of Experimental Cardiology, Department of Cardiology UMC Utrecht, University Medical Center Utrecht, Heidelberglaan 100, Room G02.523, Utrecht 3584 CX, The Netherlands
| | - Amerik Van Duijvenvoorde
- Laboratory of Experimental Cardiology, Department of Cardiology UMC Utrecht, University Medical Center Utrecht, Heidelberglaan 100, Room G02.523, Utrecht 3584 CX, The Netherlands
| | - Saskia C A De Jager
- Laboratory of Experimental Cardiology, Department of Cardiology UMC Utrecht, University Medical Center Utrecht, Heidelberglaan 100, Room G02.523, Utrecht 3584 CX, The Netherlands
| | - Ben J Van Middelaar
- Laboratory of Experimental Cardiology, Department of Cardiology UMC Utrecht, University Medical Center Utrecht, Heidelberglaan 100, Room G02.523, Utrecht 3584 CX, The Netherlands
| | - Mirjam B Smeets
- Laboratory of Experimental Cardiology, Department of Cardiology UMC Utrecht, University Medical Center Utrecht, Heidelberglaan 100, Room G02.523, Utrecht 3584 CX, The Netherlands
| | - Trent M Woodruff
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Pieter A Doevendans
- Laboratory of Experimental Cardiology, Department of Cardiology UMC Utrecht, University Medical Center Utrecht, Heidelberglaan 100, Room G02.523, Utrecht 3584 CX, The Netherlands
| | - Gerard Pasterkamp
- Laboratory of Experimental Cardiology, Department of Cardiology UMC Utrecht, University Medical Center Utrecht, Heidelberglaan 100, Room G02.523, Utrecht 3584 CX, The Netherlands
| | - C Erik Hack
- Laboratory for Translational Immunology, UMC Utrecht, Utrecht, The Netherlands
| | - Dominique P V De Kleijn
- Laboratory of Experimental Cardiology, Department of Cardiology UMC Utrecht, University Medical Center Utrecht, Heidelberglaan 100, Room G02.523, Utrecht 3584 CX, The Netherlands Interuniversity Cardiology Institute of the Netherlands, Utrecht, The Netherlands Surgery NUS and Cardiovascular Research Institute, NUHS, Singapore
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32
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Li G, Fan RM, Chen JL, Wang CM, Zeng YC, Han C, Jiao S, Xia XP, Chen W, Yao ST. Neuroprotective effects of argatroban and C5a receptor antagonist (PMX53) following intracerebral haemorrhage. Clin Exp Immunol 2014; 175:285-95. [PMID: 24117111 DOI: 10.1111/cei.12220] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2013] [Indexed: 01/14/2023] Open
Abstract
Intracerebral haemorrhage (ICH) is a subtype of stroke that associated with neurological dysfunction and inflammation, which may be ameliorated by a neuroprotective strategy targeting the complement cascade. The protective effect of C5a-receptor antagonist (PMX53) solely and in combination with thrombin antagonist (argatroban) was investigated in the ICH mouse model, respectively. Adult male C57BL/6J wild-type (WT) mice and C3(-/-) mice were randomized to receive PMX53/argatroban 1, 3 and 5 days after ICH. A double injection technique was used to infuse 25 μl of autologous whole blood into the right striatum. Mice in the sham group received only needle insertion. Brain water content and mRNA of inflammatory factors were measured on the first, third and fifth days after ICH, respectively. Neurological dysfunction was assessed using a 28-point neurological scoring system in the three cohorts, namely, on days 1, 3 and 5 following ICH. Animals treated with PMX53/argatroban demonstrated significant improvements in neurological function and fewer neurological apoptosis detected by TUNEL [terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labelling] and βIII-tubulin dual-staining compared with vehicle-treated animals. Compared with sham-treated mice, the brain water content in argatroban/PMX53-treated mice was decreased significantly in both the ipsilateral cortex and ipsilateral striatum. Administration of PMX53/argatroban provided a synergistic neuroprotective effect via reducing inflammatory factors and brain oedema, leading to improvements in neurofunctional outcome. The results of this study indicated that simultaneous blockade of the thrombin and C5a receptors represent a promising neuroprotective strategy in haemorrhagic stroke.
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Affiliation(s)
- G Li
- Department of Cerebrovascular, the First Affliated Hospital of Zunyi Medical College, Zunyi, Guizhou, China
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Molecular basis for downregulation of C5a-mediated inflammation by IgG1 immune complexes in allergy and asthma. Curr Allergy Asthma Rep 2014; 13:596-606. [PMID: 24013944 DOI: 10.1007/s11882-013-0387-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Allergy and asthma are triggered primarily by the binding of allergen-specific immunoglobulin E (IgE)-allergen complexes to their receptors, recognition of the allergens by antigen-presenting cells, and allergen presentation to the T cells. These events lead to mucus secretions, runny nose, itchy eyes, sneezing, airway hyperresponsiveness, and nasal congestion. Complement 5a (C5a) has emerged as a central molecule that mediates these allergic reactions. Many allergens and allergen-specific IgG immune complexes (IgG-ICs) cause complement activation and C5a generation. C5a interaction with its receptor (C5aR) leads to the infiltration and activation of several immunologic cell types and the secretion of pathogenic inflammatory and proinflammatory mediators. However, IgG1-IC binding to the IgG inhibitory Fc gamma receptor (FcγRIIB) suppresses C5aR-mediated inflammatory signaling and, hence, may reduce the inflammatory immune responses through this FcγRIIB-mediated pathway. Reviews of the IgG1-IC interactions with C5a-mediated inflammatory immune responses suggest that IgG1-IC-C5a inhibitory therapy may reduce inflammation in allergic diseases.
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34
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Abstract
Although new activation and regulatory mechanisms are still being identified, the basic architecture of the complement system has been known for decades. Two major roles of complement are to control certain bacterial infections and to promote clearance of apoptotic cells. In addition, although inappropriate complement activation has long been proposed to cause tissue damage in human inflammatory and autoimmune diseases, whether this is indeed true has been uncertain. However, recent studies in humans, especially those using newly available biological therapeutics, have now clearly demonstrated the pathophysiologic importance of the complement system in several rare diseases. Beyond these conditions, recent genetic studies have strongly supported an injurious role for complement in a wide array of human inflammatory, degenerative, and autoimmune diseases. This review includes an overview of complement activation, regulatory, and effector mechanisms. It then focuses on new understandings gained from genetic studies, ex vivo analyses, therapeutic trials, and animal models as well as on new research opportunities.
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Affiliation(s)
- V Michael Holers
- Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado 80045;
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35
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DI HY, Zhang YY, Chen DF. Isolation of an anti-complementary polysaccharide from the root of Bupleurum chinense and identification of its targets in complement activation cascade. Chin J Nat Med 2014; 11:177-84. [PMID: 23787186 DOI: 10.1016/s1875-5364(13)60046-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Indexed: 10/23/2022]
Abstract
AIM To isolate and characterize the anti-complementary polysaccharide from the root of Bupleurum chinense. METHODS Bioactivity-guided fractionation and purification was used to obtain the anti-complementary polysaccharide from the hot-water extract of the root of Bupleurum chinense. The polysaccharide was characterized by various chemical and spectral analyses. The anti-complementary activities were evaluated by hemolytic assay in vitro. The action targets were identified in the system with individual complement-depleted sera. RESULTS A homogeneous polysaccharide BC-PS2 was isolated as an anti-complementary agent. It was identified as a branched polysaccharide with an average molecular weight about 2 000 KDa, composed of Glc, Ara, Gal, and Man in the ratio 3.5 : 2.4 : 2.0 : 1.0, respectively, along with a trace of Rha and Xyl, and only 1.11% of protein. The main linkages of the residues of BC-PS2 include terminal, 1, 6-linked, 1, 3-linked and 1, 3, 6-linked Glcp, terminal and 1, 5-linked Araf, terminal, 1, 4-linked, 1, 6-linked and 1, 4, 6-linked Galp, terminal, and, 1, 4-linked and 1, 4, 6-linked Manp. The bioassay experiments revealed that BC-PS2 inhibited complement activation on both the classical and alternative pathways, with CH50 and AP50 of (0.222 ± 0.013) and (0.356 ± 0.032) mg·mL(-1), respectively. Preliminary mechanism studies indicated that BC-PS2 interacted with C1q, C2, and C9 components. CONCLUSION The results demonstrated that BC-PS2 is an anti-complementary polysaccharide, and should be important constituent of the root of Bupleurum chinense for its application in the treatment of diseases associated with the excessive activation of complement system.
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Affiliation(s)
- Hong-Ye DI
- School of Pharmacy, Fudan University, Shanghai 201203, China
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36
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Ruseva MM, Heurich M. Purification and characterization of human and mouse complement C3. Methods Mol Biol 2014; 1100:75-91. [PMID: 24218251 DOI: 10.1007/978-1-62703-724-2_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Complement component C3 is the most abundant complement protein in plasma, central to all three complement activation pathways and essential to complement amplification. Thus, it is one of the most extensively studied complement proteins. This chapter describes the purification of C3 from human and mouse plasma using protein precipitation, followed by classical ion exchange chromatography and gel filtration. The biochemical and functional characteristics of the purified C3 are typically assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and hemolysis assays. The hemolysis assay is a standard technique to assess complement activity monitoring the lysis of red blood cells.
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Affiliation(s)
- Marieta M Ruseva
- Department of Medicine, Centre for Complement and Infl ammation research, Imperial College, London, UK
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37
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Hou S, Qi J, Liao D, Zhang Q, Fang J, Zhou Y, Liu Y, Bai L, Zhang M, Kijlstra A, Yang P. Copy Number Variations of Complement Component C4 Are Associated With Behçet's Disease but Not With Ankylosing Spondylitis Associated With Acute Anterior Uveitis. ACTA ACUST UNITED AC 2013; 65:2963-70. [PMID: 23918728 DOI: 10.1002/art.38116] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/30/2013] [Indexed: 01/05/2023]
Affiliation(s)
- Shengping Hou
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Eye Institute, and Chongqing Key Laboratory of Ophthalmology; Chongqing China
| | - Jian Qi
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Eye Institute, and Chongqing Key Laboratory of Ophthalmology; Chongqing China
| | - Dan Liao
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Eye Institute, and Chongqing Key Laboratory of Ophthalmology; Chongqing China
| | - Qi Zhang
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Eye Institute, and Chongqing Key Laboratory of Ophthalmology; Chongqing China
| | - Jing Fang
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Eye Institute, and Chongqing Key Laboratory of Ophthalmology; Chongqing China
| | - Yan Zhou
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Eye Institute, and Chongqing Key Laboratory of Ophthalmology; Chongqing China
| | - Yunjia Liu
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Eye Institute, and Chongqing Key Laboratory of Ophthalmology; Chongqing China
| | - Lin Bai
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Eye Institute, and Chongqing Key Laboratory of Ophthalmology; Chongqing China
| | - Meifen Zhang
- Peking Union Medical College Hospital and Chinese Academy of Medical Sciences; Beijing China
| | - Aize Kijlstra
- University Eye Clinic Maastricht, Maastricht; Limburg The Netherlands
| | - Peizeng Yang
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Eye Institute, and Chongqing Key Laboratory of Ophthalmology; Chongqing China
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Gu J, Ding JY, Lu CL, Lin ZW, Chu YW, Zhao GY, Guo J, Ge D. Overexpression of CD88 predicts poor prognosis in non-small-cell lung cancer. Lung Cancer 2013; 81:259-65. [DOI: 10.1016/j.lungcan.2013.04.020] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 04/12/2013] [Accepted: 04/23/2013] [Indexed: 01/08/2023]
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39
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Di H, Zhang Y, Chen D. An anti-complementary polysaccharide from the roots of Bupleurum chinense. Int J Biol Macromol 2013; 58:179-85. [DOI: 10.1016/j.ijbiomac.2013.03.043] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 02/03/2013] [Accepted: 03/16/2013] [Indexed: 10/27/2022]
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40
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Ballanti E, Perricone C, Greco E, Ballanti M, Di Muzio G, Chimenti MS, Perricone R. Complement and autoimmunity. Immunol Res 2013; 56:477-91. [DOI: 10.1007/s12026-013-8422-y] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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41
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CR2-mediated targeting of complement inhibitors: bench-to-bedside using a novel strategy for site-specific complement modulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 735:137-54. [PMID: 23402024 DOI: 10.1007/978-1-4614-4118-2_9] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent approval of the first human complement pathway-directed therapeutics, along with high-profile genetic association studies, has catalyzed renewed biopharmaceutical interest in developing drugs that modulate the complement system. Substantial challenges remain, however, that must be overcome before widespread application of complement inhibitors in inflammatory and autoimmune diseases becomes possible. Among these challenges are the following: (1) defining the complement pathways and effector mechanisms that cause tissue injury in humans and determining whether the relative importance of each varies by disease, (2) blocking or modulating, using traditional small molecule or biologic approaches, the function of complement proteins whose circulating levels are very high and whose turnover rates are relatively rapid, especially in the setting of acute and chronic autoimmune diseases, and (3) avoiding infectious complications or impairment of other important physiological functions of complement when using systemically active complement-blocking agents. This chapter will review data that address these challenges to therapeutic development, with a focus on the development of a novel strategy of blocking specific complement pathways by targeting inhibitors using a recombinant portion of the human complement receptor type 2 (CR2/CD21) which specifically targets to sites of local complement C3 activation where C3 fragments are covalently fixed. Recently, the first of these CR2-targeted proteins has entered human phase I studies in the human disease paroxysmal nocturnal hemoglobinuria. The results of murine translational studies using CR2-targeted inhibitors strongly suggest that a guiding principle going forward in complement therapeutic development may well be to focus on developing strategies to modulate the pathway as precisely as possible by physically localizing therapeutic inhibitory effects.
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42
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Cheng SC, Sprong T, Joosten LA, van der Meer JWM, Kullberg BJ, Hube B, Schejbel L, Garred P, van Deuren M, Netea MG. Complement plays a central role in Candida albicans-induced cytokine production by human PBMCs. Eur J Immunol 2012; 42:993-1004. [DOI: 10.1002/eji.201142057] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | | | | | | | | | | | - Lone Schejbel
- Department of Clinical Immunology; Laboratory of Molecular Medicine; Rigshospitalet; Copenhagen; Denmark
| | - Peter Garred
- Department of Clinical Immunology; Laboratory of Molecular Medicine; Rigshospitalet; Copenhagen; Denmark
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43
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Dunkelberger J, Zhou L, Miwa T, Song WC. C5aR expression in a novel GFP reporter gene knockin mouse: implications for the mechanism of action of C5aR signaling in T cell immunity. THE JOURNAL OF IMMUNOLOGY 2012; 188:4032-42. [PMID: 22430734 DOI: 10.4049/jimmunol.1103141] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
C5aR is a G protein-coupled receptor for the anaphylatoxin C5a and mediates many proinflammatory reactions. C5aR signaling also has been shown to regulate T cell immunity, but its sites and mechanism of action in this process remain uncertain. In this study, we created a GFP knockin mouse and used GFP as a surrogate marker to examine C5aR expression. GFP was knocked into the 3'-untranslated region of C5ar1 by gene targeting. We show that GFP is expressed highly on Gr-1(+)CD11b(+) cells in the blood, spleen, and bone marrow and moderately on CD11b(+)F4/80(+) circulating leukocytes and elicited peritoneal macrophages. No GFP is detected on resting or activated T lymphocytes or on splenic myeloid or plasmacytoid dendritic cells. In contrast, 5-25% cultured bone marrow-derived dendritic cells expressed GFP. Interestingly, GFP knockin prevented cell surface but not intracellular C5aR expression. We conclude that C5aR is unlikely to play an intrinsic role on murine T cells and primary dendritic cells. Instead, its effect on T cell immunity in vivo may involve CD11b(+)F4/80(+) or other C5aR-expressing leukocytes. Further, our data reveal a surprising role for the 3'-untranslated region of C5aR mRNA in regulating C5aR protein targeting to the plasma membrane.
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Affiliation(s)
- Jason Dunkelberger
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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44
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Rudilla F, Fayolle C, Casares N, Durantez M, Arribillaga L, Lozano T, Villanueva L, Pio R, Sarobe P, Leclerc C, Prieto J, Lasarte JJ. Combination of a TLR4 ligand and anaphylatoxin C5a for the induction of antigen-specific cytotoxic T cell responses. Vaccine 2012; 30:2848-58. [PMID: 22387222 DOI: 10.1016/j.vaccine.2012.02.052] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 02/15/2012] [Accepted: 02/19/2012] [Indexed: 01/01/2023]
Abstract
The complement system and Toll-like receptors (TLR) are key innate defense systems which might interact synergistically on dendritic cells (DC) to reinforce adaptive immunity. In a previous work, we found that the extra domain A from fibronectin EDA (an endogenous ligand for TLR4) can favour antigen delivery to DC and induce their maturation. Given the potential of anaphylatoxins to cause inflammation and activation of myeloid cells, we hypothesized that a fusion protein between EDA, and anaphylatoxins C3a, C4a or C5a together with an antigen might improve the immunogenicity of the antigen. Naked DNA immunization with a construct expressing the fusion protein between C5a, EDA and the cytotoxic T cell epitope SIINFEKL from ovalbumin, induced strong antigen specific T cell responses. The purified recombinant fusion protein EDA-SIINFEKL-C5a induced activation of dendritic cells, the production of proinflammatory cytokines/chemokines and stimulated antigen presenting cell migration and NK cell activation. As compared to EDA-SIINFEKL, the fusion protein EDA-SIINFEKL-C5a did not induce the production of the immunosuppressive molecules IL-10, CCL17, CCL1, CXCL12 or XCL1 by DC. Moreover, EDA-SIINFEKL-C5a induced strong specific T cell responses in vivo and protected mice against E.G7-OVA tumor growth more efficiently than EDA-SIINFEKL or SIINFEKL-C5a recombinant proteins. Our results suggest that fusion proteins containing EDA, the anaphylatoxin C5a and the antigen may serve as a suitable strategy for the development of anti-tumor or anti-viral vaccines.
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Affiliation(s)
- Francesc Rudilla
- Gene Therapy and Hepatology Area and Oncology Area, Center for Applied Medical Research, University of Navarra, 31008 Pamplona, Spain
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Heeger PS, Kemper C. Novel roles of complement in T effector cell regulation. Immunobiology 2011; 217:216-24. [PMID: 21742404 DOI: 10.1016/j.imbio.2011.06.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Accepted: 06/12/2011] [Indexed: 12/17/2022]
Abstract
Our understanding of the complement system has markedly evolved from its early beginnings as a protein system merely detecting and tagging a pathogen for further clearance. For example, the repertoire of danger that complement recognizes covers currently a wide range of distinct self and non-self danger signals. Further, complement is now firmly established as instructor of adaptive B and T cell immunity. This review focuses on two the recent emerging paradigms in the field. Firstly, that complement is not only vitally required for the induction of Th1 immunity but also for the timely contraction of this protective response and therefore for prevention of autoimmunity and immune homeostasis. Secondly, that local rather than systemic complement is impacting on immune modulation during a T cell response.
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Affiliation(s)
- Peter S Heeger
- Department of Medicine, Recanati Miller Transplant Institute and Immunology Institute, Mount Sinai School of Medicine, New York, USA
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Jang JH, Liang D, Kido K, Sun Y, Clark DJ, Brennan TJ. Increased local concentration of complement C5a contributes to incisional pain in mice. J Neuroinflammation 2011; 8:80. [PMID: 21736743 PMCID: PMC3141504 DOI: 10.1186/1742-2094-8-80] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 07/07/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In our previous study, we demonstrated that local injection of complement C5a and C3a produce mechanical and heat hyperalgesia, and that C5a and C3a activate and sensitize cutaneous nociceptors in normal skin, suggesting a contribution of complement fragments to acute pain. Other studies also have shown that the complement system can be activated by surgical incision, and the systemic blockade of C5a receptor (C5aR) reduces incision-induced pain and inflammation. In this study, we further examined the possible contribution of wound area C5a to incisional pain. METHODS Using of a hind paw incisional model, the effects of a selective C5aR antagonist, PMX53, on nociceptive behaviors were measured after incision in vivo. mRNA levels of C5 and C5aR in skin, dorsal root ganglia (DRG) and spinal cord, and C5a protein levels in the skin were quantified after incision. The responses of nociceptors to C5a were also evaluated using the in vitro skin-nerve preparation. RESULTS Local administration of PMX53 suppressed heat hyperalgesia and mechanical allodynia induced by C5a injection or after hind paw incision in vivo. mRNA levels of C5 and C5aR in the skin, but not DRG and spinal cord, were dramatically increased after incision. C5a protein in the skin was also increased after incision. In vitro C5a did not increase the prevalence of fibers with ongoing activity in afferents from incised versus control, unincised skin. C5a sensitized C-fiber afferent responses to heat; however, this was less evident in afferents adjacent to the incision. PMX53 blocked sensitization of C-fiber afferents to heat by C5a but did not by itself influence ongoing activity or heat sensitivity in afferents innervating control or incised skin. The magnitude of mechanical responses was also not affected by C5a in any nociceptive fibers innervating incised or unincised skin. CONCLUSIONS This study demonstrates that high locally generated C5a levels are present in wounds for at least 72 hours after incision. In skin, C5a contributes to hypersensitivity after incision, but increased responsiveness of cutaneous nociceptors to C5a was not evident in incised skin. Thus, high local concentrations of C5a produced in wounds likely contribute to postoperative pain.
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Affiliation(s)
- Jun H Jang
- Department of Anesthesia, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
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Holers VM. The complement system in systemic lupus erythematosus. Rheumatology (Oxford) 2011. [DOI: 10.1016/b978-0-323-06551-1.00020-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Genetic regulation of microglia activation, complement expression, and neurodegeneration in a rat model of traumatic brain injury. Exp Brain Res 2010; 205:103-14. [PMID: 20602094 DOI: 10.1007/s00221-010-2342-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 06/16/2010] [Indexed: 10/19/2022]
Abstract
Secondary brain damage following traumatic brain injury in part depends on neuroinflammation, a process where genetic factors may play an important role. We examined the response to a standardized cortical contusion in two different inbred rat strains, Dark Agouti (DA) and Piebald Virol Glaxo (PVG). Both are well characterized in models of autoimmune neuroinflammation, where DA is susceptible and PVG resistant. We found that infiltration of polymorphonuclear granulocytes (PMN) at 3-day postinjury was more pronounced in PVG. DA was more infiltrated by T cells at 3-day postinjury, showed an enhanced glial activation at 7-day postinjury and higher expression of C3 complement at 7-day postinjury. Neurodegeneration, assessed by Fluoro-Jade, was also more pronounced in the DA strain at 30-day postinjury. These results demonstrate differences in the response to cortical contusion injury attributable to genetic influences and suggest a link between injury-induced inflammation and neurodegeneration. Genetic factors that regulate inflammation elicited by brain trauma may be important for the development of secondary brain damage.
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Kadam AP, Sahu A. Identification of Complin, a novel complement inhibitor that targets complement proteins factor B and C2. THE JOURNAL OF IMMUNOLOGY 2010; 184:7116-24. [PMID: 20483772 DOI: 10.4049/jimmunol.1000200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Complement factor B (fB) is a key constituent of the alternative pathway (AP). Its central role in causing inflammation and tissue injury through activation of the AP urges the need for its therapeutic targeting. In the current study, we have screened phage-displayed random peptide libraries against fB and identified a novel cyclic hendecapeptide that inhibits activation of fB and the AP. Structure-activity studies revealed that: 1) the cysteine-constrained structure of the peptide is essential for its activity; 2) Ile5, Arg6, Leu7, and Tyr8 contribute significantly to its inhibitory activity; and 3) retro-inverso modification of the peptide results in loss of its activity. Binding studies performed using surface plasmon resonance suggested that the peptide has two binding sites on fB, which are located on the Ba and Bb fragments. Studies on the mechanism of inhibition revealed that the peptide does not block the interaction of fB with the activated form of C3, thereby suggesting that the peptide inhibits fB activation primarily by inhibiting its cleavage by factor D. The peptide showed a weak effect on preformed C3 and C5 convertases. Like inhibition of fB cleavage, the peptide also inhibited C2 cleavage by activated C1s and activation of the classical as well as lectin pathways. Based on its inhibitory activities, we named the peptide Complin.
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Affiliation(s)
- Archana P Kadam
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune, India
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