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Rabeeah I, Billington E, Nal B, Sadeyen JR, Pathan AA, Iqbal M, Temperton NJ, Zipfel PF, Skerka C, Kishore U, Shelton H. Mapping the interaction sites of human and avian influenza A viruses and complement factor H. Front Immunol 2024; 15:1352022. [PMID: 38698856 PMCID: PMC11064062 DOI: 10.3389/fimmu.2024.1352022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/18/2024] [Indexed: 05/05/2024] Open
Abstract
The complement system is an innate immune mechanism against microbial infections. It involves a cascade of effector molecules that is activated via classical, lectin and alternative pathways. Consequently, many pathogens bind to or incorporate in their structures host negative regulators of the complement pathways as an evasion mechanism. Factor H (FH) is a negative regulator of the complement alternative pathway that protects "self" cells of the host from non-specific complement attack. FH has been shown to bind viruses including human influenza A viruses (IAVs). In addition to its involvement in the regulation of complement activation, FH has also been shown to perform a range of functions on its own including its direct interaction with pathogens. Here, we show that human FH can bind directly to IAVs of both human and avian origin, and the interaction is mediated via the IAV surface glycoprotein haemagglutinin (HA). HA bound to common pathogen binding footprints on the FH structure, complement control protein modules, CCP 5-7 and CCP 15-20. The FH binding to H1 and H3 showed that the interaction overlapped with the receptor binding site of both HAs, but the footprint was more extensive for the H3 HA than the H1 HA. The HA - FH interaction impeded the initial entry of H1N1 and H3N2 IAV strains but its impact on viral multicycle replication in human lung cells was strain-specific. The H3N2 virus binding to cells was significantly inhibited by preincubation with FH, whereas there was no alteration in replicative rate and progeny virus release for human H1N1, or avian H9N2 and H5N3 IAV strains. We have mapped the interaction between FH and IAV, the in vivo significance of which for the virus or host is yet to be elucidated.
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Affiliation(s)
- Iman Rabeeah
- Pirbright Institute, Woking, United Kingdom
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | | | - Béatrice Nal
- Aix-Marseille Université, CNRS, INSERM, CIML, Marseille, France
| | | | - Ansar A. Pathan
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | | | | | - Peter F. Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Uday Kishore
- Department of Veterinary Medicine, United Arab Emirates University, Al Ain, United Arab Emirates
- Zayed Centre for Biomedical Sciences, U.A.E. University, Al Ain, United Arab Emirates
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Casalino-Matsuda SM, Chen F, Gonzalez-Gonzalez FJ, Matsuda H, Nair A, Abdala-Valencia H, Budinger GS, Dong JT, Beitel GJ, Sporn PH. Myeloid Zfhx3 deficiency protects against hypercapnia-induced suppression of host defense against influenza A virus. JCI Insight 2024; 9:e170316. [PMID: 38227369 PMCID: PMC11143927 DOI: 10.1172/jci.insight.170316] [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: 03/10/2023] [Accepted: 01/10/2024] [Indexed: 01/17/2024] Open
Abstract
Hypercapnia, elevation of the partial pressure of CO2 in blood and tissues, is a risk factor for mortality in patients with severe acute and chronic lung diseases. We previously showed that hypercapnia inhibits multiple macrophage and neutrophil antimicrobial functions and that elevated CO2 increases the mortality of bacterial and viral pneumonia in mice. Here, we show that normoxic hypercapnia downregulates innate immune and antiviral gene programs in alveolar macrophages (AMØs). We also show that zinc finger homeobox 3 (Zfhx3) - a mammalian ortholog of zfh2, which mediates hypercapnic immune suppression in Drosophila - is expressed in mouse and human macrophages. Deletion of Zfhx3 in the myeloid lineage blocked the suppressive effect of hypercapnia on immune gene expression in AMØs and decreased viral replication, inflammatory lung injury, and mortality in hypercapnic mice infected with influenza A virus. To our knowledge, our results establish Zfhx3 as the first known mammalian mediator of CO2 effects on immune gene expression and lay the basis for future studies to identify therapeutic targets to interrupt hypercapnic immunosuppression in patients with advanced lung disease.
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Affiliation(s)
- S. Marina Casalino-Matsuda
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Fei Chen
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Francisco J. Gonzalez-Gonzalez
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Hiroaki Matsuda
- Department of Physical Sciences and Engineering, Wilbur Wright College, Chicago, Illinois, USA
| | - Aisha Nair
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Hiam Abdala-Valencia
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - G.R. Scott Budinger
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Research Service, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA
| | - Jin-Tang Dong
- Department of Human Cell Biology and Genetics, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Greg J. Beitel
- Department of Molecular Biosciences, Weinberg College of Arts and Sciences, Northwestern University, Evanston, Illinois, USA
| | - Peter H.S. Sporn
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Research Service, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA
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3
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Varghese PM, Kishore U, Rajkumari R. Innate and adaptive immune responses against Influenza A Virus: Immune evasion and vaccination strategies. Immunobiology 2022; 227:152279. [DOI: 10.1016/j.imbio.2022.152279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 11/25/2022]
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Varghese PM, Kishore U, Rajkumari R. Human C1q Regulates Influenza A Virus Infection and Inflammatory Response via Its Globular Domain. Int J Mol Sci 2022; 23:3045. [PMID: 35328462 PMCID: PMC8949502 DOI: 10.3390/ijms23063045] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 01/27/2023] Open
Abstract
The Influenza A virus (IAV) is a severe respiratory pathogen. C1q is the first subcomponent of the complement system's classical pathway. C1q is composed of 18 polypeptide chains. Each of these chains contains a collagen-like region located at the N terminus, and a C-terminal globular head region organized as a heterotrimeric structure (ghA, ghB and ghC). This study was aimed at investigating the complement activation-independent modulation by C1q and its individual recombinant globular heads against IAV infection. The interaction of C1q and its recombinant globular heads with IAV and its purified glycoproteins was examined using direct ELISA and far-Western blotting analysis. The effect of the complement proteins on IAV replication kinetics and immune modulation was assessed by qPCR. The IAV entry inhibitory properties of C1q and its recombinant globular heads were confirmed using cell binding and luciferase reporter assays. C1q bound IAV virions via HA, NA and M1 IAV proteins, and suppressed replication in H1N1, while promoting replication in H3N2-infected A549 cells. C1q treatment further triggered an anti-inflammatory response in H1N1 and pro-inflammatory response in H3N2-infected cells as evident from differential expression of TNF-α, NF-κB, IFN-α, IFN-β, IL-6, IL-12 and RANTES. Furthermore, C1q treatment was found to reduce luciferase reporter activity of MDCK cells transfected with H1N1 pseudotyped lentiviral particles, indicative of an entry inhibitory role of C1q against infectivity of IAV. These data appear to demonstrate the complement-independent subtype specific modulation of IAV infection by locally produced C1q.
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Affiliation(s)
- Praveen M. Varghese
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, London UB8 3PH, UK;
- School of Biosciences and Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Uday Kishore
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, London UB8 3PH, UK;
| | - Reena Rajkumari
- School of Biosciences and Technology, Vellore Institute of Technology, Vellore 632014, India
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Ostrycharz E, Hukowska-Szematowicz B. New Insights into the Role of the Complement System in Human Viral Diseases. Biomolecules 2022; 12:226. [PMID: 35204727 PMCID: PMC8961555 DOI: 10.3390/biom12020226] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/23/2022] [Accepted: 01/27/2022] [Indexed: 01/27/2023] Open
Abstract
The complement system (CS) is part of the human immune system, consisting of more than 30 proteins that play a vital role in the protection against various pathogens and diseases, including viral diseases. Activated via three pathways, the classical pathway (CP), the lectin pathway (LP), and the alternative pathway (AP), the complement system leads to the formation of a membrane attack complex (MAC) that disrupts the membrane of target cells, leading to cell lysis and death. Due to the increasing number of reports on its role in viral diseases, which may have implications for research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), this review aims to highlight significant progress in understanding and defining the role of the complement system in four groups of diseases of viral etiology: (1) respiratory diseases; (2) acute liver failure (ALF); (3) disseminated intravascular coagulation (DIC); and (4) vector-borne diseases (VBDs). Some of these diseases already present a serious global health problem, while others are a matter of concern and require the collaboration of relevant national services and scientists with the World Health Organization (WHO) to avoid their spread.
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Affiliation(s)
- Ewa Ostrycharz
- Institute of Biology, University of Szczecin, 71-412 Szczecin, Poland;
- Doctoral School of the University of Szczecin, University of Szczecin, 71-412 Szczecin, Poland
- Molecular Biology and Biotechnology Center, University of Szczecin, 71-412 Szczecin, Poland
| | - Beata Hukowska-Szematowicz
- Institute of Biology, University of Szczecin, 71-412 Szczecin, Poland;
- Molecular Biology and Biotechnology Center, University of Szczecin, 71-412 Szczecin, Poland
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6
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Varghese PM, Mukherjee S, Al-Mohanna FA, Saleh SM, Almajhdi FN, Beirag N, Alkahtani SH, Rajkumari R, Nal Rogier B, Sim RB, Idicula-Thomas S, Madan T, Murugaiah V, Kishore U. Human Properdin Released By Infiltrating Neutrophils Can Modulate Influenza A Virus Infection. Front Immunol 2021; 12:747654. [PMID: 34956182 PMCID: PMC8695448 DOI: 10.3389/fimmu.2021.747654] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
The complement system is designed to recognise and eliminate invading pathogens via activation of classical, alternative and lectin pathways. Human properdin stabilises the alternative pathway C3 convertase, resulting in an amplification loop that leads to the formation of C5 convertase, thereby acting as a positive regulator of the alternative pathway. It has been noted that human properdin on its own can operate as a pattern recognition receptor and exert immune functions outside its involvement in complement activation. Properdin can bind directly to microbial targets via DNA, sulfatides and glycosaminoglycans, apoptotic cells, nanoparticles, and well-known viral virulence factors. This study was aimed at investigating the complement-independent role of properdin against Influenza A virus infection. As one of the first immune cells to arrive at the site of IAV infection, we show here that IAV challenged neutrophils released properdin in a time-dependent manner. Properdin was found to directly interact with haemagglutinin, neuraminidase and matrix 1 protein Influenza A virus proteins in ELISA and western blot. Furthermore, modelling studies revealed that properdin could bind HA and NA of the H1N1 subtype with higher affinity compared to that of H3N2 due to the presence of an HA cleavage site in H1N1. In an infection assay using A549 cells, properdin suppressed viral replication in pH1N1 subtype while promoting replication of H3N2 subtype, as revealed by qPCR analysis of M1 transcripts. Properdin treatment triggered an anti-inflammatory response in H1N1-challenged A549 cells and a pro-inflammatory response in H3N2-infected cells, as evident from differential mRNA expression of TNF-α, NF-κB, IFN-α, IFN-β, IL-6, IL-12 and RANTES. Properdin treatment also reduced luciferase reporter activity in MDCK cells transduced with H1N1 pseudotyped lentiviral particles; however, it was increased in the case of pseudotyped H3N2 particles. Collectively, we conclude that infiltrating neutrophils at the site of IAV infection can release properdin, which then acts as an entry inhibitor for pandemic H1N1 subtype while suppressing viral replication and inducing an anti-inflammatory response. H3N2 subtype can escape this immune restriction due to altered haemagglutinin and neuraminindase, leading to enhanced viral entry, replication and pro-inflammatory response. Thus, depending on the subtype, properdin can either limit or aggravate IAV infection in the host.
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Affiliation(s)
- Praveen M Varghese
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom.,School of Biosciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Shuvechha Mukherjee
- Biomedical Informatics Centre, Indian Council of Medical Research (ICMR)-National Institute for Research in Reproductive Health, Mumbai, India
| | - Futwan A Al-Mohanna
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Souad M Saleh
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Fahad N Almajhdi
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Nazar Beirag
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Saad H Alkahtani
- Department of Zoology, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Reena Rajkumari
- School of Biosciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Beatrice Nal Rogier
- INSERM U1104 Centre d'immunologie de Marseille-Luminy (CIML), Marseille, France
| | - Robert B Sim
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Susan Idicula-Thomas
- Biomedical Informatics Centre, Indian Council of Medical Research (ICMR)-National Institute for Research in Reproductive Health, Mumbai, India
| | - Taruna Madan
- Department of Innate Immunity, Indian Council of Medical Research (ICMR)-National Institute for Research in Reproductive Health, Mumbai, India
| | - Valarmathy Murugaiah
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Uday Kishore
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
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7
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Sahu SK, Kulkarni DH, Ozanturk AN, Ma L, Kulkarni HS. Emerging roles of the complement system in host-pathogen interactions. Trends Microbiol 2021; 30:390-402. [PMID: 34600784 DOI: 10.1016/j.tim.2021.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 09/01/2021] [Accepted: 09/06/2021] [Indexed: 12/12/2022]
Abstract
The complement system has historically been entertained as a fluid-phase, hepatically derived system which protects the intravascular space from encapsulated bacteria. However, there has been an increasing appreciation for its role in protection against non-encapsulated pathogens. Specifically, we have an improved understanding of how pathogens are recognized by specific complement proteins, as well as how they trigger and evade them. Additionally, we have an improved understanding of locally derived complement proteins, many of which promote host defense. Moreover, intracellular complement proteins have been identified that facilitate local protection and barrier function despite pathogen invasion. Our review aims to summarize these advances in the field as well as provide an insight into the pathophysiological changes occurring when the system is dysregulated in infection.
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Affiliation(s)
- Sanjaya K Sahu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Devesha H Kulkarni
- Division of Gastroenterology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Ayse N Ozanturk
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Lina Ma
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Hrishikesh S Kulkarni
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.
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8
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Wilden JJ, Jacob JC, Ehrhardt C, Ludwig S, Boergeling Y. Altered Signal Transduction in the Immune Response to Influenza Virus and S. pneumoniae or S. aureus Co-Infections. Int J Mol Sci 2021; 22:5486. [PMID: 34067487 PMCID: PMC8196994 DOI: 10.3390/ijms22115486] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/14/2021] [Accepted: 05/19/2021] [Indexed: 12/23/2022] Open
Abstract
Influenza virus is a well-known respiratory pathogen, which still leads to many severe pulmonary infections in the human population every year. Morbidity and mortality rates are further increased if virus infection coincides with co-infections or superinfections caused by bacteria such as Streptococcus pneumoniae (S. pneumoniae) and Staphylococcus aureus (S. aureus). This enhanced pathogenicity is due to complex interactions between the different pathogens and the host and its immune system and is mainly governed by altered intracellular signaling processes. In this review, we summarize the recent findings regarding the innate and adaptive immune responses during co-infection with influenza virus and S. pneumoniae or S. aureus, describing the signaling pathways involved and how these interactions influence disease outcomes.
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Affiliation(s)
- Janine J. Wilden
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, 48149 Muenster, Germany; (J.J.W.); (J.C.J.); (S.L.)
| | - Jasmin C. Jacob
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, 48149 Muenster, Germany; (J.J.W.); (J.C.J.); (S.L.)
- CiM-IMPRS, The Joined Graduate School of the Cells in Motion Interfaculty Centre, University of Muenster and the International Max Planck Research School—Molecular Biomedicine, 48149 Muenster, Germany
| | - Christina Ehrhardt
- Section of Experimental Virology, Center for Molecular Biomedicine (CMB), Institute of Medical Microbiology, Jena University Hospital, 07745 Jena, Germany;
| | - Stephan Ludwig
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, 48149 Muenster, Germany; (J.J.W.); (J.C.J.); (S.L.)
- “Cells in Motion Interfaculty Center (CIMIC)”, WWU Muenster, 48149 Muenster, Germany
| | - Yvonne Boergeling
- Institute of Virology Muenster (IVM), Westfaelische Wilhelms-University Muenster, 48149 Muenster, Germany; (J.J.W.); (J.C.J.); (S.L.)
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Murugaiah V, Varghese PM, Beirag N, DeCordova S, Sim RB, Kishore U. Complement Proteins as Soluble Pattern Recognition Receptors for Pathogenic Viruses. Viruses 2021; 13:v13050824. [PMID: 34063241 PMCID: PMC8147407 DOI: 10.3390/v13050824] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 04/28/2021] [Indexed: 12/11/2022] Open
Abstract
The complement system represents a crucial part of innate immunity. It contains a diverse range of soluble activators, membrane-bound receptors, and regulators. Its principal function is to eliminate pathogens via activation of three distinct pathways: classical, alternative, and lectin. In the case of viruses, the complement activation results in effector functions such as virion opsonisation by complement components, phagocytosis induction, virolysis by the membrane attack complex, and promotion of immune responses through anaphylatoxins and chemotactic factors. Recent studies have shown that the addition of individual complement components can neutralise viruses without requiring the activation of the complement cascade. While the complement-mediated effector functions can neutralise a diverse range of viruses, numerous viruses have evolved mechanisms to subvert complement recognition/activation by encoding several proteins that inhibit the complement system, contributing to viral survival and pathogenesis. This review focuses on these complement-dependent and -independent interactions of complement components (especially C1q, C4b-binding protein, properdin, factor H, Mannose-binding lectin, and Ficolins) with several viruses and their consequences.
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Affiliation(s)
- Valarmathy Murugaiah
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; (V.M.); (P.M.V.); (N.B.); (S.D.)
| | - Praveen M. Varghese
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; (V.M.); (P.M.V.); (N.B.); (S.D.)
| | - Nazar Beirag
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; (V.M.); (P.M.V.); (N.B.); (S.D.)
| | - Syreeta DeCordova
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; (V.M.); (P.M.V.); (N.B.); (S.D.)
| | - Robert B. Sim
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK;
| | - Uday Kishore
- Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; (V.M.); (P.M.V.); (N.B.); (S.D.)
- Correspondence: or
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10
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Varghese PM, Murugaiah V, Beirag N, Temperton N, Khan HA, Alrokayan SH, Al-Ahdal MN, Nal B, Al-Mohanna FA, Sim RB, Kishore U. C4b Binding Protein Acts as an Innate Immune Effector Against Influenza A Virus. Front Immunol 2020; 11:585361. [PMID: 33488586 PMCID: PMC7820937 DOI: 10.3389/fimmu.2020.585361] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 11/20/2020] [Indexed: 02/05/2023] Open
Abstract
C4b Binding Protein (C4BP) is a major fluid phase inhibitor of the classical and lectin pathways of the complement system. Complement inhibition is achieved by binding to and restricting the role of activated complement component C4b. C4BP functions as a co-factor for factor I in proteolytic inactivation of both soluble and cell surface-bound C4b, thus restricting the formation of the C3-convertase, C4b2a. C4BP also accelerates the natural decay/dissociation of the C3 convertase. This makes C4BP a prime target for exploitation by pathogens to escape complement attack, as seen in Streptococcus pyogenes or Flavivirus. Here, we examined whether C4BP can act on its own in a complement independent manner, against pathogens. C4BP bound H1N1 and H3N2 subtypes of Influenza A Virus (IAV) most likely via multiple sites in Complement Control Protein (CCP) 1-2, 4-5, and 7-8 domains of its α-chain. In addition, C4BP CCP1-2 bound H3N2 better than H1N1. C4BP bound three IAV envelope proteins: Haemagglutinin (~70 kDa), Neuraminidase (~55 kDa), and Matrix protein 1 (~25kDa). C4BP suppressed H1N1 subtype infection into the lung epithelial cell line, A549, while it promoted infection by H3N2 subtype. C4BP restricted viral entry for H1N1 but had the opposite effect on H3N2, as evident from experiments using pseudo-typed viral particles. C4BP downregulated mRNA levels of pro-inflammatory IFN-α, IL-12, and NFκB in the case of H1N1, while it promoted a pro-inflammatory immune response by upregulating IFN- α, TNF-α, RANTES, and IL-6 in the case of H3N2. We conclude that C4BP differentially modulates the efficacy of IAV entry, and hence, replication in a target cell in a strain-dependent manner, and acts as an entry inhibitor for H1N1. Thus, CCP containing complement proteins such as factor H and C4BP may have additional defense roles against IAV that do not rely on the regulation of complement activation.
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Affiliation(s)
- Praveen M. Varghese
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
- School of Biosciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Valarmathy Murugaiah
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Nazar Beirag
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Nigel Temperton
- Viral Pseudotype Unit, Medway School of Pharmacy, University of Kent and Greenwich, Kent, United Kingdom
| | - Haseeb A. Khan
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Salman H. Alrokayan
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed N. Al-Ahdal
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Beatrice Nal
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Futwan A. Al-Mohanna
- Department of Infection and Immunity, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Robert B. Sim
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Uday Kishore
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
- *Correspondence: Uday Kishore, uday.kishore.brunel.ac.uk;
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