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Sinha A, Singh AK, Kadni TS, Mullick J, Sahu A. Virus-Encoded Complement Regulators: Current Status. Viruses 2021; 13:v13020208. [PMID: 33573085 PMCID: PMC7912105 DOI: 10.3390/v13020208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 11/29/2022] Open
Abstract
Viruses require a host for replication and survival and hence are subjected to host immunological pressures. The complement system, a crucial first response of the host immune system, is effective in targeting viruses and virus-infected cells, and boosting the antiviral innate and acquired immune responses. Thus, the system imposes a strong selection pressure on viruses. Consequently, viruses have evolved multiple countermeasures against host complement. A major mechanism employed by viruses to subvert the complement system is encoding proteins that target complement. Since viruses have limited genome size, most of these proteins are multifunctional in nature. In this review, we provide up to date information on the structure and complement regulatory functions of various viral proteins.
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Affiliation(s)
- Anwesha Sinha
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University Campus, Ganeskhind, Pune 411007, India; (A.S.); (A.K.S.); (T.S.K.)
| | - Anup Kumar Singh
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University Campus, Ganeskhind, Pune 411007, India; (A.S.); (A.K.S.); (T.S.K.)
| | - Trupti Satish Kadni
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University Campus, Ganeskhind, Pune 411007, India; (A.S.); (A.K.S.); (T.S.K.)
| | - Jayati Mullick
- Polio Virology Group, Microbial Containment Complex, ICMR-National Institute of Virology, Pune 411021, India;
| | - Arvind Sahu
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University Campus, Ganeskhind, Pune 411007, India; (A.S.); (A.K.S.); (T.S.K.)
- Correspondence: ; Tel.: +91-20-2570-8083; Fax: +91-20-2569-2259
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Agrawal P, Sharma S, Pal P, Ojha H, Mullick J, Sahu A. The imitation game: a viral strategy to subvert the complement system. FEBS Lett 2020; 594:2518-2542. [DOI: 10.1002/1873-3468.13856] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/10/2020] [Accepted: 05/23/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Palak Agrawal
- Complement Biology Laboratory National Centre for Cell Science S. P. Pune University Campus Ganeshkhind Pune 411007 India
| | - Samriddhi Sharma
- Complement Biology Laboratory National Centre for Cell Science S. P. Pune University Campus Ganeshkhind Pune 411007 India
| | - Pradipta Pal
- Complement Biology Laboratory National Centre for Cell Science S. P. Pune University Campus Ganeshkhind Pune 411007 India
| | - Hina Ojha
- Complement Biology Laboratory National Centre for Cell Science S. P. Pune University Campus Ganeshkhind Pune 411007 India
| | - Jayati Mullick
- Microbial Containment Complex ICMR‐National Institute of Virology Pune 411021 India
| | - Arvind Sahu
- Complement Biology Laboratory National Centre for Cell Science S. P. Pune University Campus Ganeshkhind Pune 411007 India
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Agrawal P, Nawadkar R, Ojha H, Kumar J, Sahu A. Complement Evasion Strategies of Viruses: An Overview. Front Microbiol 2017; 8:1117. [PMID: 28670306 PMCID: PMC5472698 DOI: 10.3389/fmicb.2017.01117] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/31/2017] [Indexed: 12/11/2022] Open
Abstract
Being a major first line of immune defense, the complement system keeps a constant vigil against viruses. Its ability to recognize large panoply of viruses and virus-infected cells, and trigger the effector pathways, results in neutralization of viruses and killing of the infected cells. This selection pressure exerted by complement on viruses has made them evolve a multitude of countermeasures. These include targeting the recognition molecules for the avoidance of detection, targeting key enzymes and complexes of the complement pathways like C3 convertases and C5b-9 formation - either by encoding complement regulators or by recruiting membrane-bound and soluble host complement regulators, cleaving complement proteins by encoding protease, and inhibiting the synthesis of complement proteins. Additionally, viruses also exploit the complement system for their own benefit. For example, they use complement receptors as well as membrane regulators for cellular entry as well as their spread. Here, we provide an overview on the complement subversion mechanisms adopted by the members of various viral families including Poxviridae, Herpesviridae, Adenoviridae, Flaviviridae, Retroviridae, Picornaviridae, Astroviridae, Togaviridae, Orthomyxoviridae and Paramyxoviridae.
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Affiliation(s)
- Palak Agrawal
- Complement Biology Laboratory, National Centre for Cell Science, Savitribai Phule Pune UniversityPune, India
| | - Renuka Nawadkar
- Complement Biology Laboratory, National Centre for Cell Science, Savitribai Phule Pune UniversityPune, India
| | - Hina Ojha
- Complement Biology Laboratory, National Centre for Cell Science, Savitribai Phule Pune UniversityPune, India
| | - Jitendra Kumar
- Complement Biology Laboratory, National Centre for Cell Science, Savitribai Phule Pune UniversityPune, India
| | - Arvind Sahu
- Complement Biology Laboratory, National Centre for Cell Science, Savitribai Phule Pune UniversityPune, India
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Abou-El-Hassan H, Zaraket H. Viral-derived complement inhibitors: current status and potential role in immunomodulation. Exp Biol Med (Maywood) 2016; 242:397-410. [PMID: 27798122 DOI: 10.1177/1535370216675772] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The complement system is one of the body's major innate immune defense mechanisms in vertebrates. Its function is to detect foreign bodies and promote their elimination through opsonisation or lysis. Complement proteins play an important role in the immunopathogenesis of several disorders. However, excessive complement activation does not confer more protection but instead leads to several autoimmune and inflammatory diseases. With inappropriate activation of the complement system, activated complement proteins and glycoproteins may damage both healthy and diseased tissues. Development of complement inhibitors represents an effective approach in controlling dysregulated complement activity and reducing disease severity, yet few studies have investigated the nature and role of novel complement inhibitory proteins of viral origin. Viral complement inhibitors have important implications in understanding the importance of complement inhibition and their role as a promising novel therapeutic approach in diseases caused by dysregulated complement function. In this review, we discuss the role and importance of complement inhibitors derived from several viruses in the scope of human inflammatory and autoimmune diseases.
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Affiliation(s)
- Hadi Abou-El-Hassan
- 1 Faculty of Medicine, American University of Beirut Medical Center, Beirut, Lebanon.,2 Center for Infectious Diseases Research, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Hassan Zaraket
- 2 Center for Infectious Diseases Research, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,3 Department of Experimental Pathology, Immunology, and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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Ojha H, Panwar HS, Gorham RD, Morikis D, Sahu A. Viral regulators of complement activation: structure, function and evolution. Mol Immunol 2014; 61:89-99. [PMID: 24976595 DOI: 10.1016/j.molimm.2014.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 05/30/2014] [Accepted: 06/01/2014] [Indexed: 11/25/2022]
Abstract
The complement system surveillance in the host is effective in controlling viral propagation. Consequently, to subvert this effector mechanism, viruses have developed a series of adaptations. One among these is encoding mimics of host regulators of complement activation (RCA) which help viruses to avoid being labeled as 'foreign' and protect them from complement-mediated neutralization and complement-enhanced antiviral adaptive immunity. In this review, we provide an overview on the structure, function and evolution of viral RCA proteins.
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Affiliation(s)
- Hina Ojha
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Hemendra Singh Panwar
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Ronald D Gorham
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Dimitrios Morikis
- Department of Bioengineering, University of California, Riverside, CA 92521, USA.
| | - Arvind Sahu
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India.
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Dissection of functional sites in herpesvirus saimiri complement control protein homolog. J Virol 2012; 87:282-95. [PMID: 23077301 DOI: 10.1128/jvi.01867-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Herpesvirus saimiri is known to encode a homolog of human complement regulators named complement control protein homolog (CCPH). We have previously reported that this virally encoded inhibitor effectively inactivates complement by supporting factor I-mediated inactivation of complement proteins C3b and C4b (termed cofactor activity), as well as by accelerating the irreversible decay of the classical/lectin and alternative pathway C3 convertases (termed decay-accelerating activity). To fine map its functional sites, in the present study, we have generated a homology model of CCPH and performed substitution mutagenesis of its conserved residues. Functional analyses of 24 substitution mutants of CCPH indicated that (i) amino acids R118 and F144 play a critical role in imparting C3b and C4b cofactor activities, (ii) amino acids R35, K142, and K191 are required for efficient decay of the C3 convertases, (iii) positively charged amino acids of the linker regions, which are dubbed to be critical for functioning in other complement regulators, are not crucial for its function, and (iv) S100K and G110D mutations substantially enhance its decay-accelerating activities without affecting the cofactor activities. Overall, our data point out that ionic interactions form a major component of the binding interface between CCPH and its interacting partners.
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Pyaram K, Yadav VN, Reza MJ, Sahu A. Virus–complement interactions: an assiduous struggle for dominance. Future Virol 2010. [DOI: 10.2217/fvl.10.60] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The complement system is a major component of the innate immune system that recognizes invading pathogens and eliminates them by means of an array of effector mechanisms, in addition to using direct lytic destruction. Viruses, in spite of their small size and simple composition, are also deftly recognized and neutralized by the complement system. In turn, as a result of years of coevolution with the host, viruses have developed multiple mechanisms to evade the host complement. These complex interactions between the complement system and viruses have been an area of focus for over three decades. In this article, we provide a broad overview of the field using key examples and up-to-date information on the complement-evasion strategies of viruses.
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Affiliation(s)
- Kalyani Pyaram
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Viveka Nand Yadav
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Malik Johid Reza
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India
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Ahmad M, Raut S, Pyaram K, Kamble A, Mullick J, Sahu A. Domain Swapping Reveals Complement Control Protein Modules Critical for Imparting Cofactor and Decay-Accelerating Activities in Vaccinia Virus Complement Control Protein. THE JOURNAL OF IMMUNOLOGY 2010; 185:6128-37. [DOI: 10.4049/jimmunol.1001617] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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