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Li J, Cui H, Yao Y, Niu J, Zhang J, Zheng X, Cui M, Liu J, Cheng T, Gao Y, Guo Q, Yu S, Wang L, Huang Z, Huang J, Zhang K, Wang C, Meng G. Anti-influenza activity of CPAVM1 protease secreted by Bacillus subtilis LjM2. Antiviral Res 2024; 228:105919. [PMID: 38851592 DOI: 10.1016/j.antiviral.2024.105919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/12/2024] [Accepted: 05/24/2024] [Indexed: 06/10/2024]
Abstract
Bacillus spp. has been considered a promising source for identifying new antimicrobial substances, including anti-viral candidates. Here, we successfully isolated a number of bacteria strains from aged dry citrus peel (Chenpi). Of note, the culture supernatant of a new isolate named Bacillus subtilis LjM2 demonstrated strong inhibition of influenza A virus (IAV) infection in multiple experimental systems in vitro and in vivo. In addition, the anti-viral effect of LjM2 was attributed to its direct lysis of viral particles. Further analysis showed that a protease which we named CPAVM1 isolated from the culture supernatant of LjM2 was the key component responsible for its anti-viral function. Importantly, the therapeutic effect of CPAVM1 was still significant when applied 12 hours after IAV infection of experimental mice. Moreover, we found that the CPAVM1 protease cleaved multiple IAV proteins via targeting basic amino acid Arg or Lys. Furthermore, this study reveals the molecular structure and catalytic mechanism of CPAVM1 protease. During catalysis, Tyr75, Tyr77, and Tyr102 are important active sites. Therefore, the present work identified a special protease CPAVM1 secreted by a new strain of Bacillus subtilis LjM2 against influenza A virus infection via direct cleavage of critical viral proteins, thus facilitates future biotechnological applications of Bacillus subtilis LjM2 and the protease CPAVM1.
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Affiliation(s)
- Juan Li
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China; Nanjing Advanced Academy of Life and Health, Nanjing, Jiangsu, 211135, China
| | - Hong Cui
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China; Suzhou Medical College, Soochow University, Suzhou, Jiangsu, 215006, China
| | - Yujie Yao
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China; School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China
| | - Junling Niu
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Jing Zhang
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Xu Zheng
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Mengmeng Cui
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Jia Liu
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Tong Cheng
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Yuhui Gao
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Qiuhong Guo
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Shi Yu
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Lanfeng Wang
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Zhong Huang
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Jing Huang
- School of Life Science, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Ke Zhang
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Chengyuan Wang
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China.
| | - Guangxun Meng
- The Center for Microbes, Development and Health, Key Laboratory of Immune Response and Immunotherapy, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China; Nanjing Advanced Academy of Life and Health, Nanjing, Jiangsu, 211135, China; Suzhou Medical College, Soochow University, Suzhou, Jiangsu, 215006, China; School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China.
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Zhang L, Ke D, Li Y, Zhang H, Zhang X, Wang S, Ni S, Peng B, Zeng H, Hou T, Du Y, Pan P, Yu Y, Chen W. Design and synthesis of 7-membered lactam fused hydroxypyridinones as potent metal binding pharmacophores (MBPs) for inhibiting influenza virus PA N endonuclease. Eur J Med Chem 2024; 276:116639. [PMID: 38964259 DOI: 10.1016/j.ejmech.2024.116639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/06/2024]
Abstract
Since influenza virus RNA polymerase subunit PAN is a dinuclear Mn2+ dependent endonuclease, metal-binding pharmacophores (MBPs) with Mn2+ coordination has been elucidated as a promising strategy to develop PAN inhibitors for influenza treatment. However, few attentions have been paid to the relationship between the optimal arrangement of the donor atoms in MBPs and anti-influenza A virus (IAV) efficacy. Given that, the privileged hydroxypyridinones fusing a seven-membered lactam ring with diverse side chains, chiral centers or cyclic systems were designed and synthesized. A structure-activity relationship study resulted in a hit compound 16l (IC50 = 2.868 ± 0.063 μM against IAV polymerase), the seven-membered lactam ring of which was fused a pyrrolidine ring. Further optimization of the hydrophobic binding groups on 16l afforded a lead compound (R, S)-16s, which exhibited a 64-fold more potent inhibitory activity (IC50 = 0.045 ± 0.002 μM) toward IAV polymerase. Moreover, (R, S)-16s demonstrated a potent anti-IAV efficacy (EC50 = 0.134 ± 0.093 μM) and weak cytotoxicity (CC50 = 15.35 μM), indicating the high selectivity of (R, S)-16s. Although the lead compound (R, S)-16s exhibited a little weaker activity than baloxavir, these findings illustrated the utility of a metal coordination-based strategy in generating novel MBPs with potent anti-influenza activity.
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Affiliation(s)
- Lei Zhang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Di Ke
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Institute of Health and Medicine, Hefei Comprehensive National Science Center, Hefei, 230601, China
| | - Yuting Li
- The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, China
| | - Hui Zhang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Xi Zhang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Jinhua Institute of Zhejiang University, Jinhua, Zhejiang, 321299, China
| | - Sihan Wang
- The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, China
| | - Shaokai Ni
- The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, China
| | - Bo Peng
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Huixuan Zeng
- The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, China
| | - Tingjun Hou
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Yushen Du
- The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, China
| | - Peichen Pan
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Yongping Yu
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Jinhua Institute of Zhejiang University, Jinhua, Zhejiang, 321299, China; School of Pharmacy, Xinjiang Medical University, Urumqi, 830054, China
| | - Wenteng Chen
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Jinhua Institute of Zhejiang University, Jinhua, Zhejiang, 321299, China.
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Liu Y, Luo Z. Repurposing Anticancer Drugs Targeting the MAPK/ERK Signaling Pathway for the Treatment of Respiratory Virus Infections. Int J Mol Sci 2024; 25:6946. [PMID: 39000055 PMCID: PMC11240997 DOI: 10.3390/ijms25136946] [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: 05/04/2024] [Revised: 06/16/2024] [Accepted: 06/19/2024] [Indexed: 07/16/2024] Open
Abstract
Respiratory virus infections remain a significant challenge to human health and the social economy. The symptoms range from mild rhinitis and nasal congestion to severe lower respiratory tract dysfunction and even mortality. The efficacy of therapeutic drugs targeting respiratory viruses varies, depending upon infection time and the drug resistance engendered by a high frequency of viral genome mutations, necessitating the development of new strategies. The MAPK/ERK pathway that was well delineated in the 1980s represents a classical signaling cascade, essential for cell proliferation, survival, and differentiation. Since this pathway is constitutively activated in many cancers by oncogenes, several drugs inhibiting Raf/MEK/ERK have been developed and currently used in anticancer treatment. Two decades ago, it was reported that viruses such as HIV and influenza viruses could exploit the host cellular MAPK/ERK pathway for their replication. Thus, it would be feasible to repurpose this category of the pathway inhibitors for the treatment of respiratory viral infections. The advantage is that the host genes are not easy to mutate such that the drug resistance rarely occurs during short-period treatment of viruses. Therefore, in this review we will summarize the research progress on the role of the MAPK/ERK pathway in respiratory virus amplification and discuss the potential of the pathway inhibitors (MEK inhibitors) in the treatment of respiratory viral infections.
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Affiliation(s)
| | - Zhijun Luo
- Medical Department, Queen Mary School, Nanchang University, Nanchang 330031, China;
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Xu L, Ren W, Wang Q, Li J. Advances in Nucleic Acid Universal Influenza Vaccines. Vaccines (Basel) 2024; 12:664. [PMID: 38932393 PMCID: PMC11209422 DOI: 10.3390/vaccines12060664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 06/13/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024] Open
Abstract
Currently, vaccination with influenza vaccines is still an effective strategy to prevent infection by seasonal influenza virus in spite of some drawbacks with them. However, due to the rapid evolution of influenza viruses, including seasonal influenza viruses and emerging zoonotic influenza viruses, there is an urgent need to develop broad-spectrum influenza vaccines to cope with the evolution of influenza viruses. Nucleic acid vaccines might meet the requirements well. Nucleic acid vaccines are classified into DNA vaccines and RNA vaccines. Both types induced potent cellular and humoral immune responses, showing great promise for the development of universal influenza vaccines. In this review, the current status of an influenza universal nucleic acid vaccine was summarized.
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Affiliation(s)
- Liang Xu
- Department of Infectious Disease, The Second Hospital of Nanjing, Affiliated to Nanjing University of Chinese Medicine, Nanjing 210003, China; (L.X.); (W.R.); (Q.W.)
| | - Weigang Ren
- Department of Infectious Disease, The Second Hospital of Nanjing, Affiliated to Nanjing University of Chinese Medicine, Nanjing 210003, China; (L.X.); (W.R.); (Q.W.)
| | - Qin Wang
- Department of Infectious Disease, The Second Hospital of Nanjing, Affiliated to Nanjing University of Chinese Medicine, Nanjing 210003, China; (L.X.); (W.R.); (Q.W.)
| | - Junwei Li
- Department of Infectious Disease, The Second Hospital of Nanjing, Affiliated to Nanjing University of Chinese Medicine, Nanjing 210003, China; (L.X.); (W.R.); (Q.W.)
- Medical Innovation Center for Infectious Disease of Jiangsu Province, Nanjing 210003, China
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Bessonne M, Morel J, Nevers Q, Da Costa B, Ballandras-Colas A, Chenavier F, Grange M, Roussel A, Crépin T, Delmas B. Antiviral activity of intracellular nanobodies targeting the influenza virus RNA-polymerase core. PLoS Pathog 2024; 20:e1011642. [PMID: 38875296 PMCID: PMC11210859 DOI: 10.1371/journal.ppat.1011642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 06/27/2024] [Accepted: 05/15/2024] [Indexed: 06/16/2024] Open
Abstract
Influenza viruses transcribe and replicate their genome in the nucleus of the infected cells, two functions that are supported by the viral RNA-dependent RNA-polymerase (FluPol). FluPol displays structural flexibility related to distinct functional states, from an inactive form to conformations competent for replication and transcription. FluPol machinery is constituted by a structurally-invariant core comprising the PB1 subunit stabilized with PA and PB2 domains, whereas the PA endonuclease and PB2 C-domains can pack in different configurations around the core. To get insights into the functioning of FluPol, we selected single-domain nanobodies (VHHs) specific of the influenza A FluPol core. When expressed intracellularly, some of them exhibited inhibitory activity on type A FluPol, but not on the type B one. The most potent VHH (VHH16) binds PA and the PA-PB1 dimer with an affinity below the nanomolar range. Ectopic intracellular expression of VHH16 in virus permissive cells blocks multiplication of different influenza A subtypes, even when induced at late times post-infection. VHH16 was found to interfere with the transport of the PA-PB1 dimer to the nucleus, without affecting its handling by the importin β RanBP5 and subsequent steps in FluPol assembly. Using FluPol mutants selected after passaging in VHH16-expressing cells, we identified the VHH16 binding site at the interface formed by PA residues with the N-terminus of PB1, overlapping or close to binding sites of two host proteins, ANP32A and RNA-polymerase II RPB1 subunit which are critical for virus replication and transcription, respectively. These data suggest that the VHH16 neutralization is likely due to several activities, altering the import of the PA-PB1 dimer into the nucleus as well as inhibiting specifically virus transcription and replication. Thus, the VHH16 binding site represents a new Achilles' heel for FluPol and as such, a potential target for antiviral development.
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Affiliation(s)
- Mélissa Bessonne
- Unité de Virologie et Immunologie moléculaires, INRAE, Université Paris-Saclay, Jouy-en-Josas, France
| | - Jessica Morel
- Unité de Virologie et Immunologie moléculaires, INRAE, Université Paris-Saclay, Jouy-en-Josas, France
| | - Quentin Nevers
- Unité de Virologie et Immunologie moléculaires, INRAE, Université Paris-Saclay, Jouy-en-Josas, France
| | - Bruno Da Costa
- Unité de Virologie et Immunologie moléculaires, INRAE, Université Paris-Saclay, Jouy-en-Josas, France
| | | | - Florian Chenavier
- Institut de biologie structurale, CNRS, Université de Grenoble, Grenoble, France
| | - Magali Grange
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), CNRS, Université d’Aix-Marseille, Marseille, France
| | - Alain Roussel
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), CNRS, Université d’Aix-Marseille, Marseille, France
| | - Thibaut Crépin
- Institut de biologie structurale, CNRS, Université de Grenoble, Grenoble, France
| | - Bernard Delmas
- Unité de Virologie et Immunologie moléculaires, INRAE, Université Paris-Saclay, Jouy-en-Josas, France
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Guo X, Zhou Y, Yan H, An Q, Liang C, Liu L, Qian J. Molecular Markers and Mechanisms of Influenza A Virus Cross-Species Transmission and New Host Adaptation. Viruses 2024; 16:883. [PMID: 38932174 PMCID: PMC11209369 DOI: 10.3390/v16060883] [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: 04/16/2024] [Revised: 05/25/2024] [Accepted: 05/28/2024] [Indexed: 06/28/2024] Open
Abstract
Influenza A viruses continue to be a serious health risk to people and result in a large-scale socio-economic loss. Avian influenza viruses typically do not replicate efficiently in mammals, but through the accumulation of mutations or genetic reassortment, they can overcome interspecies barriers, adapt to new hosts, and spread among them. Zoonotic influenza A viruses sporadically infect humans and exhibit limited human-to-human transmission. However, further adaptation of these viruses to humans may result in airborne transmissible viruses with pandemic potential. Therefore, we are beginning to understand genetic changes and mechanisms that may influence interspecific adaptation, cross-species transmission, and the pandemic potential of influenza A viruses. We also discuss the genetic and phenotypic traits associated with the airborne transmission of influenza A viruses in order to provide theoretical guidance for the surveillance of new strains with pandemic potential and the prevention of pandemics.
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Affiliation(s)
- Xinyi Guo
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China;
| | - Yang Zhou
- Guangzhou Eighth People’s Hospital, Guangzhou Medical University, Guangzhou 510440, China
| | - Huijun Yan
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; (H.Y.); (C.L.)
| | - Qing An
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China;
| | - Chudan Liang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; (H.Y.); (C.L.)
- Guangdong Provincial Highly Pathogenic Microorganism Science Data Center, Guangzhou 510080, China
| | - Linna Liu
- Guangzhou Eighth People’s Hospital, Guangzhou Medical University, Guangzhou 510440, China
| | - Jun Qian
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China;
- Guangdong Provincial Highly Pathogenic Microorganism Science Data Center, Guangzhou 510080, China
- Shenzhen Key Laboratory of Pathogenic Microbes and Biosafety, Shenzhen 518107, China
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Jurkovic CM, Raisch J, Tran S, Nguyen HD, Lévesque D, Scott MS, Campos EI, Boisvert FM. Replisome Proximal Protein Associations and Dynamic Proteomic Changes at Stalled Replication Forks. Mol Cell Proteomics 2024; 23:100767. [PMID: 38615877 PMCID: PMC11101681 DOI: 10.1016/j.mcpro.2024.100767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 03/19/2024] [Accepted: 04/11/2024] [Indexed: 04/16/2024] Open
Abstract
DNA replication is a fundamental cellular process that ensures the transfer of genetic information during cell division. Genome duplication takes place in S phase and requires a dynamic and highly coordinated recruitment of multiple proteins at replication forks. Various genotoxic stressors lead to fork instability and collapse, hence the need for DNA repair pathways. By identifying the multitude of protein interactions implicated in those events, we can better grasp the complex and dynamic molecular mechanisms that facilitate DNA replication and repair. Proximity-dependent biotin identification was used to identify associations with 17 proteins within four core replication components, namely the CDC45/MCM2-7/GINS helicase that unwinds DNA, the DNA polymerases, replication protein A subunits, and histone chaperones needed to disassemble and reassemble chromatin. We further investigated the impact of genotoxic stress on these interactions. This analysis revealed a vast proximity association network with 108 nuclear proteins further modulated in the presence of hydroxyurea; 45 being enriched and 63 depleted. Interestingly, hydroxyurea treatment also caused a redistribution of associations with 11 interactors, meaning that the replisome is dynamically reorganized when stressed. The analysis identified several poorly characterized proteins, thereby uncovering new putative players in the cellular response to DNA replication arrest. It also provides a new comprehensive proteomic framework to understand how cells respond to obstacles during DNA replication.
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Affiliation(s)
- Carla-Marie Jurkovic
- Faculty of Medicine and Health Sciences, Department of Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jennifer Raisch
- Faculty of Medicine and Health Sciences, Department of Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Stephanie Tran
- Genetics & Genome Biology Program, Department of Molecular Biology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Hoang Dong Nguyen
- Faculty of Medicine and Health Sciences, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Dominique Lévesque
- Faculty of Medicine and Health Sciences, Department of Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Michelle S Scott
- Faculty of Medicine and Health Sciences, Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Eric I Campos
- Genetics & Genome Biology Program, Department of Molecular Biology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
| | - François-Michel Boisvert
- Faculty of Medicine and Health Sciences, Department of Immunology and Cell Biology, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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Xia C, Wang T, Hahm B. Triggering Degradation of Host Cellular Proteins for Robust Propagation of Influenza Viruses. Int J Mol Sci 2024; 25:4677. [PMID: 38731896 PMCID: PMC11083682 DOI: 10.3390/ijms25094677] [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: 04/03/2024] [Revised: 04/22/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024] Open
Abstract
Following infection, influenza viruses strive to establish a new host cellular environment optimized for efficient viral replication and propagation. Influenza viruses use or hijack numerous host factors and machinery not only to fulfill their own replication process but also to constantly evade the host's antiviral and immune response. For this purpose, influenza viruses appear to have formulated diverse strategies to manipulate the host proteins or signaling pathways. One of the most effective tactics is to specifically induce the degradation of the cellular proteins that are detrimental to the virus life cycle. Here, we summarize the cellular factors that are deemed to have been purposefully degraded by influenza virus infection. The focus is laid on the mechanisms for the protein ubiquitination and degradation in association with facilitated viral amplification. The fate of influenza viral infection of hosts is heavily reliant on the outcomes of the interplay between the virus and the host antiviral immunity. Understanding the processes of how influenza viruses instigate the protein destruction pathways could provide a foundation for the development of advanced therapeutics to target host proteins and conquer influenza.
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Affiliation(s)
- Chuan Xia
- Department of Microbiology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Ting Wang
- Department of Bioengineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China;
| | - Bumsuk Hahm
- Departments of Surgery & Molecular Microbiology and Immunology, University of Missouri, Columbia, MO 65212, USA
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9
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Na L, Sun L, Yu M, Zhang Y, Zhang Y, Zhang Z, Zhang H, Qi T, Guo W, Guo X, Wang S, Wang J, Lin Y, Wang X. Avian ANP32A incorporated in avian influenza A virions promotes interspecies transmission by priming early viral replication in mammals. SCIENCE ADVANCES 2024; 10:eadj4163. [PMID: 38295177 PMCID: PMC10830118 DOI: 10.1126/sciadv.adj4163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 12/28/2023] [Indexed: 02/02/2024]
Abstract
Species-specific differences in acidic nuclear phosphoprotein 32 family member A (ANP32A) determine the restriction of avian-signature polymerase in mammalian cells. Mutations that evade this restriction, such as PB2-E627K, are frequently acquired when avian influenza A viruses jump from avian hosts to mammalian hosts. However, the mechanism underlying this adaptation process is still unclear. Here, we report that host factor ANP32 proteins can be incorporated into influenza viral particles through combination with the viral RNA polymerase (vPol) and then transferred into targeted cells where they support virus replication. The packaging of the ANP32 proteins into influenza viruses is dependent on their affinity with the vPol. Avian ANP32A (avANP32A) delivered by avian influenza A virions primes early viral replication in mammalian cells, thereby favoring the downstream interspecies transmission event by increasing the total amount of virus carrying adaptive mutations. Our study clarifies one role of avANP32A where it is used by avian influenza virus to help counteract the restriction barrier in mammals.
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Affiliation(s)
- Lei Na
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Liuke Sun
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Mengmeng Yu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Yingzhi Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Yuan Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Zhenyu Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Haili Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Ting Qi
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Wei Guo
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Xing Guo
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Shida Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Jingfei Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Yuezhi Lin
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Xiaojun Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
- Institute of Western Agriculture, The Chinese Academy of Agricultural Sciences, Harbin 150069, China
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10
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Zhang L, Shao Y, Wang Y, Yang Q, Guo J, Gao GF, Deng T. Twenty natural amino acid substitution screening at the last residue 121 of influenza A virus NS2 protein reveals the critical role of NS2 in promoting virus genome replication by coordinating with viral polymerase. J Virol 2024; 98:e0116623. [PMID: 38054704 PMCID: PMC10804943 DOI: 10.1128/jvi.01166-23] [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: 08/02/2023] [Accepted: 11/20/2023] [Indexed: 12/07/2023] Open
Abstract
Both influenza A virus genome transcription (vRNA→mRNA) and replication (vRNA→cRNA→vRNA), catalyzed by the influenza RNA polymerase (FluPol), are dynamically regulated across the virus life cycle. It has been reported that the last amino acid I121 of the viral NS2 protein plays a critical role in promoting viral genome replication in influenza mini-replicon systems. Here, we performed a 20 natural amino acid substitution screening at residue NS2-I121 in the context of virus infection. We found that the hydrophobicity of the residue 121 is essential for virus survival. Interestingly, through serial passage of the rescued mutant viruses, we further identified adaptive mutations PA-K19E and PB1-S713N on FluPol which could effectively compensate for the replication-promoting defect caused by NS2-I121 mutation in the both mini-replicon and virus infection systems. Structural analysis of different functional states of FluPol indicates that PA-K19E and PB1-S713N could stabilize the replicase conformation of FluPol. By using a cell-based NanoBiT complementary reporter assay, we further demonstrate that both wild-type NS2 and PA-K19E/PB1-S713N could enhance FluPol dimerization, which is necessary for genome replication. These results reveal the critical role NS2 plays in promoting viral genome replication by coordinating with FluPol.IMPORTANCEThe intrinsic mechanisms of influenza RNA polymerase (FluPol) in catalyzing viral genome transcription and replication have been largely resolved. However, the mechanisms of how transcription and replication are dynamically regulated remain elusive. We recently reported that the last amino acid of the viral NS2 protein plays a critical role in promoting viral genome replication in an influenza mini-replicon system. Here, we conducted a 20 amino acid substitution screening at the last residue 121 in virus rescue and serial passage. Our results demonstrate that the replication-promoting function of NS2 is important for virus survival and efficient multiplication. We further show evidence that NS2 and NS2-I121 adaptive mutations PA-K19E/PB1-S713N regulate virus genome replication by promoting FluPol dimerization. This work highlights the coordination between NS2 and FluPol in fulfilling efficient genome replication. It further advances our understanding of the regulation of viral RNA synthesis for influenza A virus.
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Affiliation(s)
- Lei Zhang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- />Institute of Pediatrics, Shenzhen Children’s Hospital, Shenzhen, China
| | - Yuekun Shao
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yingying Wang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Qiuxian Yang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jiamei Guo
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - George F. Gao
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Tao Deng
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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11
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Dey S, Mondal A. Unveiling the role of host kinases at different steps of influenza A virus life cycle. J Virol 2024; 98:e0119223. [PMID: 38174932 PMCID: PMC10805039 DOI: 10.1128/jvi.01192-23] [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] [Indexed: 01/05/2024] Open
Abstract
Influenza viruses remain a major public health concern causing contagious respiratory illnesses that result in around 290,000-650,000 global deaths every year. Their ability to constantly evolve through antigenic shifts and drifts leads to the emergence of newer strains and resistance to existing drugs and vaccines. To combat this, there is a critical need for novel antiviral drugs through the introduction of host-targeted therapeutics. Influenza viruses encode only 14 gene products that get extensively modified through phosphorylation by a diverse array of host kinases. Reversible phosphorylation at serine, threonine, or tyrosine residues dynamically regulates the structure, function, and subcellular localization of viral proteins at different stages of their life cycle. In addition, kinases influence a plethora of signaling pathways that also regulate virus propagation by modulating the host cell environment thus establishing a critical virus-host relationship that is indispensable for executing successful infection. This dependence on host kinases opens up exciting possibilities for developing kinase inhibitors as next-generation anti-influenza therapy. To fully capitalize on this potential, extensive mapping of the influenza virus-host kinase interaction network is essential. The key focus of this review is to outline the molecular mechanisms by which host kinases regulate different steps of the influenza A virus life cycle, starting from attachment-entry to assembly-budding. By assessing the contributions of different host kinases and their specific phosphorylation events during the virus life cycle, we aim to develop a holistic overview of the virus-host kinase interaction network that may shed light on potential targets for novel antiviral interventions.
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Affiliation(s)
- Soumik Dey
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Arindam Mondal
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, India
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12
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El-Kafrawy SA, Alsayed SM, Faizo AA, Bajrai LH, Uthman NA, Alsaeed MS, Hassan AM, Alquthami KM, Alandijany TA, Zumla A, Azhar EI. Genetic diversity and molecular analysis of human influenza virus among pilgrims during Hajj. Heliyon 2024; 10:e23027. [PMID: 38163192 PMCID: PMC10755270 DOI: 10.1016/j.heliyon.2023.e23027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 11/16/2023] [Accepted: 11/24/2023] [Indexed: 01/03/2024] Open
Abstract
The risk of transmission of respiratory tract infections is considerably enhanced at mass gathering (MG) religious events. Hajj is an annual Islamic MG event with approximately 3 million Muslim pilgrims from over 180 countries concentrated in Makkah, Saudi Arabia. This study aimed to investigate the genetic diversity of influenza viruses circulating among pilgrims during the Hajj pilgrimage. We performed a cross-sectional analytical study where nasopharyngeal swabs (NPs) from pilgrims with respiratory tract illnesses presenting to healthcare facilities during the 2019 Hajj were screened for influenza viruses. Influenza A subtypes and influenza B lineages were determined by multiplex RT-PCR for positive influenza samples. The phylogenetic analysis was carried out for the hemagglutination (HA) gene. Out of 185 nasopharyngeal samples, 54 were positive for the human influenza virus. Of these, 27 were influenza A H1N1 and 19 H3N2, 4 were untypable influenza A, and 4 were influenza B. Phylogenetic analysis revealed that the H1N1 and H3N2 strains differentiated into different and independent genetic groups and formed close clusters with selected strains of influenza viruses from various locations. To conclude, this study demonstrates a high genetic diversity of circulating influenza A subtypes among pilgrims during the Hajj Season. There is a need for further larger studies to investigate in-depth the genetic characteristics of influenza viruses and other respiratory viruses during Hajj seasons.
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Affiliation(s)
- Sherif A. El-Kafrawy
- Special Infectious Agents Unit BSL-3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Salma M. Alsayed
- Special Infectious Agents Unit BSL-3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Arwa A. Faizo
- Special Infectious Agents Unit BSL-3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Leena H. Bajrai
- Special Infectious Agents Unit BSL-3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Biochemistry, Faculty of Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Norah A. Uthman
- Special Infectious Agents Unit BSL-3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Moneerah S. Alsaeed
- Special Infectious Agents Unit BSL-3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Ahmed M. Hassan
- Special Infectious Agents Unit BSL-3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | | | - Thamir A. Alandijany
- Special Infectious Agents Unit BSL-3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Alimuddin Zumla
- Division of Infection and Immunity, Centre for Clinical Microbiology, University College London Royal Free Campus, London WC1E 6DE, UK
- NIHR Biomedical Research Centre, UCL Hospitals NHS Foundation Trust, London W1T 7DN, UK
| | - Esam I. Azhar
- Special Infectious Agents Unit BSL-3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
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13
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Samir A, Elshemey W, Elfiky A. Can de-phosphorylation of serine-5 in the C-terminal domain of human polymerase II affect its interaction with the PA C-terminal domain of bat Flu A polymerase? J Biomol Struct Dyn 2024; 42:1-10. [PMID: 36455997 DOI: 10.1080/07391102.2022.2152872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 11/23/2022] [Indexed: 12/03/2022]
Abstract
Influenza viruses depend on the host transcription machinery to create their new progeny viral mRNA. They need the host transcription machinery to hijack the 5'-capped RNA from the host RNAs in order to utilize them to activate their viral transcription. In this study, we computationally regenerated the interaction between 3 heptad repeats, phosphorylated at the fifth serine residue in each repeat, from human polymerase and the CT D of the PA subunit of viral RNA polymerase (Holo 3SEP). We also studied the effect of the de-phosphorylation of the Serine-5 in the middle heptad repeat on the stability of the interaction (Holo 2SEP). The dynamics of the protein association and the heptad repeat in both cases are studied using appropriate in silico tools. This is followed by applying the MM-GBSA method based on relative binding estimation to show the effect of the de-phosphorylation of the middle Serine-5. Results indicate a clear change in total relative binding energy in Holo 2SEP, compared to Holo 3SEP, with no shift in occupied amino acids involved in the interaction in both cases. Knowing that de-phosphorylation of one serine-5 has no significant contribution to the investigated interactions opens the door for further studies to understand the role of the middle heptad serine-5 in these interactions, as its dephosphorylation caused a decrease by ≈13% in the binding affinity values obtained using MM-GBSA. The current in silico study represents a one-step-ahead insight into the RNA-dependent RNA polymerase (RdRP) mechanism that is yet to be verified in the lab.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Ahmed Samir
- Biophysics Department, Faculty of Sciences, Cairo University, Giza, Egypt
| | - Wael Elshemey
- Department of Physics, Faculty of Science, Islamic University of Madinah, Madinah, Saudi Arabia
| | - Abdo Elfiky
- Biophysics Department, Faculty of Sciences, Cairo University, Giza, Egypt
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14
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Swaminath S, Russell AB. The use of single-cell RNA-seq to study heterogeneity at varying levels of virus-host interactions. PLoS Pathog 2024; 20:e1011898. [PMID: 38236826 PMCID: PMC10796064 DOI: 10.1371/journal.ppat.1011898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2024] Open
Abstract
The outcome of viral infection depends on the diversity of the infecting viral population and the heterogeneity of the cell population that is infected. Until almost a decade ago, the study of these dynamic processes during viral infection was challenging and limited to certain targeted measurements. Presently, with the use of single-cell sequencing technology, the complex interface defined by the interactions of cells with infecting virus can now be studied across the breadth of the transcriptome in thousands of individual cells simultaneously. In this review, we will describe the use of single-cell RNA sequencing (scRNA-seq) to study the heterogeneity of viral infections, ranging from individual virions to the immune response between infected individuals. In addition, we highlight certain key experimental limitations and methodological decisions that are critical to analyzing scRNA-seq data at each scale.
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Affiliation(s)
- Sharmada Swaminath
- School of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Alistair B. Russell
- School of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
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15
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Sabsay KR, te Velthuis AJW. Negative and ambisense RNA virus ribonucleocapsids: more than protective armor. Microbiol Mol Biol Rev 2023; 87:e0008223. [PMID: 37750733 PMCID: PMC10732063 DOI: 10.1128/mmbr.00082-23] [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] [Indexed: 09/27/2023] Open
Abstract
SUMMARYNegative and ambisense RNA viruses are the causative agents of important human diseases such as influenza, measles, Lassa fever, and Ebola hemorrhagic fever. The viral genome of these RNA viruses consists of one or more single-stranded RNA molecules that are encapsidated by viral nucleocapsid proteins to form a ribonucleoprotein complex (RNP). This RNP acts as protection, as a scaffold for RNA folding, and as the context for viral replication and transcription by a viral RNA polymerase. However, the roles of the viral nucleoproteins extend beyond these functions during the viral infection cycle. Recent advances in structural biology techniques and analysis methods have provided new insights into the formation, function, dynamics, and evolution of negative sense virus nucleocapsid proteins, as well as the role that they play in host innate immune responses against viral infection. In this review, we discuss the various roles of nucleocapsid proteins, both in the context of RNPs and in RNA-free states, as well as the open questions that remain.
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Affiliation(s)
- Kimberly R. Sabsay
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Aartjan J. W. te Velthuis
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
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16
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Liu C, Hu L, Dong G, Zhang Y, Ferreira da Silva-Júnior E, Liu X, Menéndez-Arias L, Zhan P. Emerging drug design strategies in anti-influenza drug discovery. Acta Pharm Sin B 2023; 13:4715-4732. [PMID: 38045039 PMCID: PMC10692392 DOI: 10.1016/j.apsb.2023.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/12/2023] [Accepted: 08/03/2023] [Indexed: 12/05/2023] Open
Abstract
Influenza is an acute respiratory infection caused by influenza viruses (IFV), According to the World Health Organization (WHO), seasonal IFV epidemics result in approximately 3-5 million cases of severe illness, leading to about half a million deaths worldwide, along with severe economic losses and social burdens. Unfortunately, frequent mutations in IFV lead to a certain lag in vaccine development as well as resistance to existing antiviral drugs. Therefore, it is of great importance to develop anti-IFV drugs with high efficiency against wild-type and resistant strains, needed in the fight against current and future outbreaks caused by different IFV strains. In this review, we summarize general strategies used for the discovery and development of antiviral agents targeting multiple IFV strains (including those resistant to available drugs). Structure-based drug design, mechanism-based drug design, multivalent interaction-based drug design and drug repurposing are amongst the most relevant strategies that provide a framework for the development of antiviral drugs targeting IFV.
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Affiliation(s)
- Chuanfeng Liu
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
| | - Lide Hu
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
| | - Guanyu Dong
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
| | - Ying Zhang
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
| | - Edeildo Ferreira da Silva-Júnior
- Laboratory of Medicinal Chemistry, Institute of Pharmaceutical Sciences, Federal University of Alagoas, Maceió 57072-970, Alagoas, Brazil
| | - Xinyong Liu
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
| | - Luis Menéndez-Arias
- Centro de Biología Molecular “Severo Ochoa” (Consejo Superior de Investigaciones Científicas & Universidad Autónoma de Madrid), Madrid 28049, Spain
| | - Peng Zhan
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
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17
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Zhu Z, Fan H, Fodor E. Defining the minimal components of the influenza A virus replication machinery via an in vitro reconstitution system. PLoS Biol 2023; 21:e3002370. [PMID: 37943954 PMCID: PMC10662765 DOI: 10.1371/journal.pbio.3002370] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 11/21/2023] [Accepted: 10/09/2023] [Indexed: 11/12/2023] Open
Abstract
During influenza A virus infection, the viral RNA polymerase transcribes the viral negative-sense segmented RNA genome and replicates it in a two-step process via complementary RNA within viral ribonucleoprotein (vRNP) complexes. While numerous viral and host factors involved in vRNP functions have been identified, dissecting the roles of individual factors remains challenging due to the complex cellular environment in which vRNP activity has been studied. To overcome this challenge, we reconstituted viral transcription and a full cycle of replication in a test tube using vRNPs isolated from virions and recombinant factors essential for these processes. This novel system uncovers the minimal components required for influenza virus replication and also reveals new roles of regulatory factors in viral replication. Moreover, it sheds light on the molecular interplay underlying the temporal regulation of viral transcription and replication. Our highly robust in vitro system enables systematic functional analysis of factors modulating influenza virus vRNP activity and paves the way for imaging key steps of viral transcription and replication.
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Affiliation(s)
- Zihan Zhu
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Haitian Fan
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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18
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Ghorbani A, Ngunjiri JM, Rendon G, Brooke CB, Kenney SP, Lee CW. Diversity and Complexity of Internally Deleted Viral Genomes in Influenza A Virus Subpopulations with Enhanced Interferon-Inducing Phenotypes. Viruses 2023; 15:2107. [PMID: 37896883 PMCID: PMC10612045 DOI: 10.3390/v15102107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023] Open
Abstract
Influenza A virus (IAV) populations harbor large subpopulations of defective-interfering particles characterized by internally deleted viral genomes. These internally deleted genomes have demonstrated the ability to suppress infectivity and boost innate immunity, rendering them promising for therapeutic and immunogenic applications. In this study, we aimed to investigate the diversity and complexity of the internally deleted IAV genomes within a panel of plaque-purified avian influenza viruses selected for their enhanced interferon-inducing phenotypes. Our findings unveiled that the abundance and diversity of internally deleted viral genomes were contingent upon the viral subculture and plaque purification processes. We observed a heightened occurrence of internally deleted genomes with distinct junctions in viral clones exhibiting enhanced interferon-inducing phenotypes, accompanied by additional truncation in the nonstructural 1 protein linker region (NS1Δ76-86). Computational analyses suggest the internally deleted IAV genomes can encode a broad range of carboxy-terminally truncated and intrinsically disordered proteins with variable lengths and amino acid composition. Further research is imperative to unravel the underlying mechanisms driving the increased diversity of internal deletions within the genomes of viral clones exhibiting enhanced interferon-inducing capacities and to explore their potential for modulating cellular processes and immunity.
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Affiliation(s)
- Amir Ghorbani
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA;
- Center for Food Animal Health, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691, USA
| | - John M. Ngunjiri
- Center for Food Animal Health, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691, USA
| | - Gloria Rendon
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA (C.B.B.)
| | - Christopher B. Brooke
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA (C.B.B.)
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Scott P. Kenney
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA;
- Center for Food Animal Health, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691, USA
| | - Chang-Won Lee
- Southeast Poultry Research Laboratory, US National Poultry Research Center, USDA, ARS, Athens, GA 30605, USA
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19
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Yang Q, Elz AE, Panis M, Liu T, Nilsson-Payant BE, Blanco-Melo D. Modulation of Influenza A virus NS1 expression reveals prioritization of host response antagonism at single-cell resolution. Front Microbiol 2023; 14:1267078. [PMID: 37876781 PMCID: PMC10590924 DOI: 10.3389/fmicb.2023.1267078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 09/19/2023] [Indexed: 10/26/2023] Open
Abstract
Influenza A virus (IAV) is an important human respiratory pathogen that causes significant seasonal epidemics and potential devastating pandemics. As part of its life cycle, IAV encodes the multifunctional protein NS1, that, among many roles, prevents immune detection and limits interferon (IFN) production. As distinct host immune pathways exert different selective pressures against IAV, as replication progresses, we expect a prioritization in the host immune antagonism by NS1. In this work, we profiled bulk transcriptomic differences in a primary bronchial epithelial cell model facing IAV infections at distinct NS1 levels. We further demonstrated that, at single cell level, the intracellular amount of NS1 in-part shapes the heterogeneity of the host response. We found that modulation of NS1 levels reveal a ranking in its inhibitory roles: modest NS1 expression is sufficient to inhibit immune detection, and thus the expression of pro-inflammatory cytokines (including IFNs), but higher levels are required to inhibit IFN signaling and ISG expression. Lastly, inhibition of chaperones related to the unfolded protein response requires the highest amount of NS1, often associated with later stages of viral replication. This work demystifies some of the multiple functions ascribed to IAV NS1, highlighting the prioritization of NS1 in antagonizing the different pathways involved in the host response to IAV infection.
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Affiliation(s)
- Qing Yang
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, United States
| | - Anna E. Elz
- Innovation Laboratory, Fred Hutchinson Cancer Center, Seattle, WA, United States
| | - Maryline Panis
- Department of Microbiology, New York University, New York, NY, United States
| | - Ting Liu
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, United States
| | - Benjamin E. Nilsson-Payant
- TWINCORE Centre for Experimental and Clinical Infection Research, Institute of Experimental Virology, Hannover, Germany
- Cluster of Excellence RESIST (EXC 2155), Hanover Medical School, Hanover, Germany
| | - Daniel Blanco-Melo
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, United States
- Herbold Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, United States
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20
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Sun H, Tu S, Luo D, Dai C, Jin M, Chen H, Zou J, Zhou H. Protein arginine methyltransferase 5 mediates arginine symmetric dimethylation of influenza A virus PB2 and supports viral replication. J Med Virol 2023; 95:e29171. [PMID: 37830751 DOI: 10.1002/jmv.29171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 09/08/2023] [Accepted: 10/03/2023] [Indexed: 10/14/2023]
Abstract
Influenza A virus (IAV) relies on intricate and highly coordinated associations with host factors for efficient replication and transmission. Characterization of such factors holds great significance for development of anti-IAV drugs. Our study identified protein arginine methyltransferase 5 (PRMT5) as a novel host factor indispensable for IAV replication. Silencing PRMT5 resulted in drastic repression of IAV replication. Our findings revealed that PRMT5 interacts with each protein component of viral ribonucleoproteins (vRNPs) and promotes arginine symmetric dimethylation of polymerase basic 2 (PB2). Overexpression of PRMT5 enhanced viral polymerase activity in a dose-dependent manner, emphasizing its role in genome transcription and replication of IAV. Moreover, analysis of PB2 protein sequences across various subtypes of IAVs demonstrated the high conservation of potential RG motifs recognized by PRMT5. Overall, our study suggests that PRMT5 supports IAV replication by facilitating viral polymerase activity by interacting with PB2 and promoting its arginine symmetric dimethylation. This study deepens our understanding of how IAV manipulates host factors to facilitate its replication and highlights the great potential of PRMT5 to serve as an anti-IAV therapeutic target.
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Affiliation(s)
- Huimin Sun
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Shaoyu Tu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Didan Luo
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Chao Dai
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Meilin Jin
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Huanchun Chen
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
- Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Jiahui Zou
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Hongbo Zhou
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
- Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
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21
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Gilbertson B, Duncan M, Subbarao K. Role of the viral polymerase during adaptation of influenza A viruses to new hosts. Curr Opin Virol 2023; 62:101363. [PMID: 37672875 DOI: 10.1016/j.coviro.2023.101363] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 08/15/2023] [Accepted: 08/15/2023] [Indexed: 09/08/2023]
Abstract
As a group, influenza-A viruses (IAV) infect a wide range of animal hosts, however, they are constrained to infecting selected host species by species-specific interactions between the host and virus, that are required for efficient replication of the viral RNA genome. When IAV cross the species barrier, they acquire mutations in the viral genome to enable interactions with the new host factors, or to compensate for their loss. The viral polymerase genes polymerase basic 1, polymerase basic 2, and polymerase-acidic are important sites of host adaptation. In this review, we discuss why the viral polymerase is so vital to the process of host adaptation, look at some of the known viral mutations, and host factors involved in adaptation, particularly of avian IAV to mammalian hosts.
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Affiliation(s)
- Brad Gilbertson
- Department of Microbiology and Immunology, University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Melanie Duncan
- WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Kanta Subbarao
- Department of Microbiology and Immunology, University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia.
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22
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Abstract
The nonsegmented, negative-strand RNA viruses (nsNSVs), also known as the order Mononegavirales, have a genome consisting of a single strand of negative-sense RNA. Integral to the nsNSV replication cycle is the viral polymerase, which is responsible for transcribing the viral genome, to produce an array of capped and polyadenylated messenger RNAs, and replicating it to produce new genomes. To perform the different steps that are necessary for these processes, the nsNSV polymerases undergo a series of coordinated conformational transitions. While much is still to be learned regarding the intersection of nsNSV polymerase dynamics, structure, and function, recently published polymerase structures, combined with a history of biochemical and molecular biology studies, have provided new insights into how nsNSV polymerases function as dynamic machines. In this review, we consider each of the steps involved in nsNSV transcription and replication and suggest how these relate to solved polymerase structures.
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Affiliation(s)
- Mohamed Ouizougun-Oubari
- Department of Virology, Immunology & Microbiology, National Emerging Infectious Diseases Laboratories, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA;
| | - Rachel Fearns
- Department of Virology, Immunology & Microbiology, National Emerging Infectious Diseases Laboratories, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA;
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23
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Camacho-Zarco AR, Yu L, Krischuns T, Dedeoglu S, Maurin D, Bouvignies G, Crépin T, Ruigrok RWH, Cusack S, Naffakh N, Blackledge M. Multivalent Dynamic Colocalization of Avian Influenza Polymerase and Nucleoprotein by Intrinsically Disordered ANP32A Reveals the Molecular Basis of Human Adaptation. J Am Chem Soc 2023; 145:20985-21001. [PMID: 37707433 PMCID: PMC10540212 DOI: 10.1021/jacs.3c06965] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Indexed: 09/15/2023]
Abstract
Adaptation of avian influenza RNA polymerase (FluPol) to human cells requires mutations on the 627-NLS domains of the PB2 subunit. The E627K adaptive mutation compensates a 33-amino-acid deletion in the acidic intrinsically disordered domain of the host transcription regulator ANP32A, a deletion that restricts FluPol activity in mammalian cells. The function of ANP32A in the replication transcription complex and in particular its role in host restriction remains poorly understood. Here we characterize ternary complexes formed between ANP32A, FluPol, and the viral nucleoprotein, NP, supporting the putative role of ANP32A in shuttling NP to the replicase complex. We demonstrate that while FluPol and NP can simultaneously bind distinct linear motifs on avian ANP32A, the deletion in the shorter human ANP32A blocks this mode of colocalization. NMR reveals that NP and human-adapted FluPol, containing the E627 K mutation, simultaneously bind the identical extended linear motif on human ANP32A in an electrostatically driven, highly dynamic and multivalent ternary complex. This study reveals a probable molecular mechanism underlying host adaptation, whereby E627K, which enhances the basic surface of the 627 domain, is selected to confer the necessary multivalent properties to allow ANP32A to colocalize NP and FluPol in human cells.
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Affiliation(s)
- Aldo R. Camacho-Zarco
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Lefan Yu
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Tim Krischuns
- Institut
Pasteur, Université Paris Cité,
CNRS UMR3569, Unité Biologie des ARN et Virus Influenza, 75015 Paris, France
| | - Selin Dedeoglu
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Damien Maurin
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Guillaume Bouvignies
- Laboratoire
des Biomolécules, Département de Chimie, École
Normale Supérieur, UPMC Université Paris 06, CNRS, PSL Research University, 24 rue Lhomond, 75005 Paris, France
| | - Thibaut Crépin
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Rob W. H. Ruigrok
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Stephan Cusack
- European
Molecular Biology Laboratory, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Nadia Naffakh
- Institut
Pasteur, Université Paris Cité,
CNRS UMR3569, Unité Biologie des ARN et Virus Influenza, 75015 Paris, France
| | - Martin Blackledge
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
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24
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Roe K. Eight influenza virus cellular manipulations which can boost concurrent SARS-CoV-2 infections to severe outcomes. Hum Cell 2023; 36:1581-1592. [PMID: 37306884 DOI: 10.1007/s13577-023-00923-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/22/2023] [Indexed: 06/13/2023]
Abstract
Viral pathogens in the lungs can cause severe outcomes, including acute lung injury and acute respiratory distress syndrome. Dangerous respiratory pathogens include some influenza A and B viruses, and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Unfortunately, concurrent infections of influenza virus and SARS-CoV-2 increase severe outcome probabilities. Influenza viruses have eight cellular manipulations which can assist concurrent SARS-CoV-2 viral infections. The eight cellular manipulations include: (1) viral protein binding with cellular sensors to block antiviral transcription factors and cytokine expressions, (2) viral protein binding with cell proteins to impair cellular pre-messenger ribonucleic acid splicing, (3) increased ribonucleic acid virus replication through the phosphatidylinositol 3-kinase/Akt (protein kinase B) pathway, (4) regulatory ribonucleic acids to manipulate cellular sensors and pathways to suppress antiviral defenses, (5) exosomes to transmit influenza virus to uninfected cells to weaken cellular defenses before SARS-CoV-2 infection, (6) increased cellular cholesterol and lipids to improve virion synthesis stability, quality and virion infectivity, (7) increased cellular autophagy, benefiting influenza virus and SARS-CoV-2 replications and (8) adrenal gland stimulation to produce glucocorticoids, which suppress immune cells, including reduced synthesis of cytokines, chemokines and adhesion molecules. Concurrent infections by one of the influenza viruses and SARS-CoV-2 will increase the probability of severe outcomes, and with sufficient synergy potentially enable the recurrence of tragic pandemics.
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25
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Khrustalev VV, Stojarov AN, Shen C, Khrustaleva TA. Consequences of asymmetric mutational pressure for the dynamic of linear B-cell epitopes repertoire of influenza a virus neuraminidase rearrangement. Biosystems 2023; 231:104970. [PMID: 37442364 DOI: 10.1016/j.biosystems.2023.104970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/02/2023] [Accepted: 07/02/2023] [Indexed: 07/15/2023]
Abstract
Full-length nucleotide sequences of avian influenza A virus neuraminidase coding region (20,631 sequences) were analyzed and compared with those isolated from viruses infecting human and swine (63,750 sequences). If in fourfold degenerate sites there is asymmetric A-bias that may be more or less asymmetric depending on the type of neuraminidase and the host, than in twofold degenerate sites from third codon positions there is a strong asymmetric U-bias in coding regions of N4, N5, and N8 isolated from viruses infecting birds, as well as in those of N1 and N2 isolated from viruses infecting human, swine, and birds, while in coding regions of N9 isolated from birds, there is surprisingly strong C-bias, and in sequences of N3, N6, and N7 the usage of C is quite close to the level of U. Revealed stabilization of both U and C in twofold degenerate sites is the evidence of frequent changes in mutational pressure direction. Asymmetric mutational pressure was one of the sources of amino acid replacements that resulted in an equal percentage of sites with appeared and disappeared linear B-cell epitopes in N1, N2, N4, and N5 (33.62-35.33% vs. 32.41-36.45%, respectively), and controlled by the immune pressure it resulted in a stronger tendency to disappear for B-cell epitopes of N3, N6, N7, N8, and N9 of avian viruses (8.74-28.77% vs. 28.96-38.89%). The lack of correlation between nucleotide usages in fourfold and twofold degenerate sites for three nucleotides, except U, is a strong evidence of mutational pressure theory.
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Affiliation(s)
- Vladislav Victorovich Khrustalev
- Department of General Chemistry, Belarusian State Medical University, Dzerzinskogo, 83, Minsk, Belarus; Multidisciplinary Diagnostic Laboratory, Institute of Physiology of the National Academy of Sciences of Belarus, Academicheskaya, 28, Minsk, Belarus.
| | | | - Chenguang Shen
- Southern Medical University, Guanzhou, China No.1023-1063 South Shatai Road, Baiyun District, Guangzhou City, Guangdong Province, 510515, PR China
| | - Tatyana Aleksandrovna Khrustaleva
- Multidisciplinary Diagnostic Laboratory, Institute of Physiology of the National Academy of Sciences of Belarus, Academicheskaya, 28, Minsk, Belarus
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26
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Li H, Wu Y, Li M, Guo L, Gao Y, Wang Q, Zhang J, Lai Z, Zhang X, Zhu L, Lan P, Rao Z, Liu Y, Liang H. An intermediate state allows influenza polymerase to switch smoothly between transcription and replication cycles. Nat Struct Mol Biol 2023; 30:1183-1192. [PMID: 37488357 DOI: 10.1038/s41594-023-01043-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 06/23/2023] [Indexed: 07/26/2023]
Abstract
Influenza polymerase (FluPol) transcribes viral mRNA at the beginning of the viral life cycle and initiates genome replication after viral protein synthesis. However, it remains poorly understood how FluPol switches between its transcription and replication states, especially given that the structural bases of these two functions are fundamentally different. Here we propose a mechanism by which FluPol achieves functional switching between these two states through a previously unstudied conformation, termed an 'intermediate state'. Using cryo-electron microscopy, we obtained a structure of the intermediate state of H5N1 FluPol at 3.7 Å, which is characterized by a blocked cap-binding domain and a contracted core region. Structural analysis results suggest that the intermediate state may allow FluPol to transition smoothly into either the transcription or replication state. Furthermore, we show that the formation of the intermediate state is required for both the transcription and replication activities of FluPol, leading us to conclude that the transcription and replication cycles of FluPol are regulated via this intermediate state.
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Affiliation(s)
- Huanhuan Li
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
- Department of General Surgery, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yixi Wu
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
| | - Minke Li
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
| | - Lu Guo
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yaqi Gao
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
| | - Quan Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jihua Zhang
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
| | - Zhaohua Lai
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
| | - Xing Zhang
- Departments of Biophysics and Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Center of Cryo Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, China
| | - Lixin Zhu
- Department of General Surgery, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Ping Lan
- Department of General Surgery, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zihe Rao
- Laboratory of Structural Biology, Tsinghua University, Beijing, China
| | - Yingfang Liu
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China.
- Department of General Surgery, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
| | - Huanhuan Liang
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China.
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27
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Jallow MM, Barry MA, Fall A, Ndiaye NK, Kiori D, Sy S, Goudiaby D, Niang MN, Fall G, Fall M, Dia N. Influenza A Virus in Pigs in Senegal and Risk Assessment of Avian Influenza Virus (AIV) Emergence and Transmission to Human. Microorganisms 2023; 11:1961. [PMID: 37630521 PMCID: PMC10459748 DOI: 10.3390/microorganisms11081961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
We conducted an active influenza surveillance in the single pig slaughterhouse in Dakar to investigate the epidemiology and genetic characteristics of influenza A viruses (IAVs) and to provide serologic evidence of avian influenza virus (AIV) infection in pigs at interfaces with human populations in Senegal. Nasal swab and blood samples were collected on a weekly basis from the same animal immediately after slaughter. Influenza A viruses were diagnosed using RT-qPCR and a subset of positive samples for H3 and H1 subtypes were selected for full genome amplification and NGS sequencing. Serum samples were tested by HI assay for the detection of antibodies recognizing four AIVs, including H9N2, H5N1, H7N7 and H5N2. Between September 2018 and December 2019, 1691 swine nasal swabs were collected and tested. Influenza A virus was detected in 30.7% (520/1691), and A/H1N1pdm09 virus was the most commonly identified subtype with 38.07% (198/520), followed by A/H1N2 (16.3%) and A/H3N2 (5.2%). Year-round influenza activity was noted in pigs, with the highest incidence between June and September. Phylogenetic analyses revealed that the IAVs were closely related to human IAV strains belonging to A/H1N1pdm09 and seasonal H3N2 lineages. Genetic analysis revealed that Senegalese strains possessed several key amino acid changes, including D204 and N241D in the receptor binding site, S31N in the M2 gene and P560S in the PA protein. Serological analyses revealed that 83.5% (95%CI = 81.6-85.3) of the 1636 sera tested were positive for the presence of antibodies against either H9N2, H5N1, H7N7 or H5N2. Influenza H7N7 (54.3%) and H9N2 (53.6%) were the dominant avian subtypes detected in Senegalese pigs. Given the co-circulation of multiple subtypes of influenza viruses among Senegalese pigs, the potential exists for the emergence of new hybrid viruses of unpredictable zoonotic and pandemic potential in the future.
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Affiliation(s)
- Mamadou Malado Jallow
- Institut Pasteur de Dakar, Département de Virologie, Dakar BP 220, Senegal; (M.M.J.); (A.F.); (N.K.N.); (D.K.); (S.S.); (D.G.); (M.N.N.); (G.F.)
- Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP de Dakar, Dakar BP 206, Senegal;
| | - Mamadou Aliou Barry
- Institut Pasteur de Dakar, Unité d’Epidémiologie des Maladies Infectieuses, Dakar BP 220, Senegal;
| | - Amary Fall
- Institut Pasteur de Dakar, Département de Virologie, Dakar BP 220, Senegal; (M.M.J.); (A.F.); (N.K.N.); (D.K.); (S.S.); (D.G.); (M.N.N.); (G.F.)
| | - Ndiendé Koba Ndiaye
- Institut Pasteur de Dakar, Département de Virologie, Dakar BP 220, Senegal; (M.M.J.); (A.F.); (N.K.N.); (D.K.); (S.S.); (D.G.); (M.N.N.); (G.F.)
| | - Davy Kiori
- Institut Pasteur de Dakar, Département de Virologie, Dakar BP 220, Senegal; (M.M.J.); (A.F.); (N.K.N.); (D.K.); (S.S.); (D.G.); (M.N.N.); (G.F.)
| | - Sara Sy
- Institut Pasteur de Dakar, Département de Virologie, Dakar BP 220, Senegal; (M.M.J.); (A.F.); (N.K.N.); (D.K.); (S.S.); (D.G.); (M.N.N.); (G.F.)
| | - Déborah Goudiaby
- Institut Pasteur de Dakar, Département de Virologie, Dakar BP 220, Senegal; (M.M.J.); (A.F.); (N.K.N.); (D.K.); (S.S.); (D.G.); (M.N.N.); (G.F.)
| | - Mbayame Ndiaye Niang
- Institut Pasteur de Dakar, Département de Virologie, Dakar BP 220, Senegal; (M.M.J.); (A.F.); (N.K.N.); (D.K.); (S.S.); (D.G.); (M.N.N.); (G.F.)
| | - Gamou Fall
- Institut Pasteur de Dakar, Département de Virologie, Dakar BP 220, Senegal; (M.M.J.); (A.F.); (N.K.N.); (D.K.); (S.S.); (D.G.); (M.N.N.); (G.F.)
| | - Malick Fall
- Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP de Dakar, Dakar BP 206, Senegal;
| | - Ndongo Dia
- Institut Pasteur de Dakar, Département de Virologie, Dakar BP 220, Senegal; (M.M.J.); (A.F.); (N.K.N.); (D.K.); (S.S.); (D.G.); (M.N.N.); (G.F.)
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28
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Jakob C, Lovate GL, Desirò D, Gießler L, Smyth R, Marquet R, Lamkiewicz K, Marz M, Schwemmle M, Bolte H. Sequential disruption of SPLASH-identified vRNA-vRNA interactions challenges their role in influenza A virus genome packaging. Nucleic Acids Res 2023; 51:6479-6494. [PMID: 37224537 PMCID: PMC10325904 DOI: 10.1093/nar/gkad442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/02/2023] [Accepted: 05/10/2023] [Indexed: 05/26/2023] Open
Abstract
A fundamental step in the influenza A virus (IAV) replication cycle is the coordinated packaging of eight distinct genomic RNA segments (i.e. vRNAs) into a viral particle. Although this process is thought to be controlled by specific vRNA-vRNA interactions between the genome segments, few functional interactions have been validated. Recently, a large number of potentially functional vRNA-vRNA interactions have been detected in purified virions using the RNA interactome capture method SPLASH. However, their functional significance in coordinated genome packaging remains largely unclear. Here, we show by systematic mutational analysis that mutant A/SC35M (H7N7) viruses lacking several prominent SPLASH-identified vRNA-vRNA interactions involving the HA segment package the eight genome segments as efficiently as the wild-type virus. We therefore propose that the vRNA-vRNA interactions identified by SPLASH in IAV particles are not necessarily critical for the genome packaging process, leaving the underlying molecular mechanism elusive.
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Affiliation(s)
- Celia Jakob
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Gabriel L Lovate
- RNA Bioinformatics and High-Throughput Analysis, Faculty of Mathematics and Computer Science, Friedrich Schiller University Jena, Germany
| | - Daniel Desirò
- Department of Biochemistry, University of Cambridge, CambridgeCB2 1QW, UK
| | - Lara Gießler
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
| | - Redmond P Smyth
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Faculty of Medicine, Würzburg, Germany
| | - Roland Marquet
- Architecture et Réactivité de l’ARN, Université de Strasbourg, CNRS, IBMC, Strasbourg, France
| | - Kevin Lamkiewicz
- RNA Bioinformatics and High-Throughput Analysis, Faculty of Mathematics and Computer Science, Friedrich Schiller University Jena, Germany
- German Center for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
- European Virus Bioinformatics Center (EVBC), Jena, Germany
| | - Manja Marz
- RNA Bioinformatics and High-Throughput Analysis, Faculty of Mathematics and Computer Science, Friedrich Schiller University Jena, Germany
- German Center for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
- European Virus Bioinformatics Center (EVBC), Jena, Germany
- FLI Leibniz Institute for Age Research, Jena, Germany
| | - Martin Schwemmle
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Hardin Bolte
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
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29
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Han X, Ye Q, Xu P. Incident changes in the prevalence of influenza type A virus among children before and after COVID-19 pandemic in Hangzhou, China. THE CLINICAL RESPIRATORY JOURNAL 2023. [PMID: 37385422 PMCID: PMC10363810 DOI: 10.1111/crj.13659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/12/2023] [Accepted: 06/20/2023] [Indexed: 07/01/2023]
Affiliation(s)
- Xiucui Han
- Department of Clinical Laboratory, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China
| | - Qing Ye
- Department of Clinical Laboratory, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China
| | - Pengfei Xu
- Clinical Laboratory, Zhejiang Hospital, Hangzhou, China
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30
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Zhang L, Wang Y, Shao Y, Guo J, Gao GF, Deng T. Fine Regulation of Influenza Virus RNA Transcription and Replication by Stoichiometric Changes in Viral NS1 and NS2 Proteins. J Virol 2023; 97:e0033723. [PMID: 37166301 PMCID: PMC10231140 DOI: 10.1128/jvi.00337-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 04/14/2023] [Indexed: 05/12/2023] Open
Abstract
In the influenza virus life cycle, viral RNA (vRNA) transcription (vRNA→mRNA) and replication (vRNA→cRNA→vRNA), catalyzed by the viral RNA-dependent RNA polymerase in the host cell nucleus, are delicately controlled, and the levels of the three viral RNA species display very distinct synthesis dynamics. However, the underlying mechanisms remain elusive. Here, we demonstrate that in the context of virus infection with cycloheximide treatment, the expression of viral nonstructural protein 1 (NS1) can stimulate primary transcription, while the expression of viral NS2 inhibits primary transcription. It is known that the NS1 and NS2 proteins are expressed with different timings from unspliced and spliced mRNAs of the viral NS segment. We then simulated the synthesis dynamics of NS1 and NS2 proteins during infection by dose-dependent transfection experiments in ribonucleoprotein (RNP) reconstitution systems. We found that the early-expressed NS1 protein can stimulate viral mRNA synthesis, while the late-expressed NS2 protein can inhibit mRNA synthesis but can promote vRNA synthesis in a manner highly consistent with the dynamic changes in mRNA/vRNA in the virus life cycle. Furthermore, we observed that the coexistence of sufficient NS1 and NS2, close to the status of the NS1 and NS2 levels in the late stage of infection, could boost vRNA synthesis to the highest efficiency. We also identified key functional amino acids of NS1 and NS2 involved in these regulations. Together, we propose that the stoichiometric changes in the viral NS1 and NS2 proteins during infection are responsible for the fine regulation of viral RNA transcription and replication. IMPORTANCE In order to ensure efficient multiplication, influenza virus transcribes and replicates its segmented, negative-sense viral RNA genome in highly ordered dynamics across the virus life cycle. How the virus achieves such regulation remains poorly understood. Here, we demonstrate that the stoichiometric changes in the viral NS1 and NS2 proteins during infection could be responsible for the fine regulation of the distinct dynamics of viral RNA transcription and replication. We thus propose a fundamental mechanism exploited by influenza virus to dynamically regulate the synthesis of its viral RNA through the delicate control of viral NS1 and NS2 protein expression.
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Affiliation(s)
- Lei Zhang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yingying Wang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yuekun Shao
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jiamei Guo
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - George F. Gao
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Tao Deng
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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AbuBakar U, Amrani L, Kamarulzaman FA, Karsani SA, Hassandarvish P, Khairat JE. Avian Influenza Virus Tropism in Humans. Viruses 2023; 15:833. [PMID: 37112812 PMCID: PMC10142937 DOI: 10.3390/v15040833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/12/2023] [Accepted: 03/17/2023] [Indexed: 03/29/2023] Open
Abstract
An influenza pandemic happens when a novel influenza A virus is able to infect and transmit efficiently to a new, distinct host species. Although the exact timing of pandemics is uncertain, it is known that both viral and host factors play a role in their emergence. Species-specific interactions between the virus and the host cell determine the virus tropism, including binding and entering cells, replicating the viral RNA genome within the host cell nucleus, assembling, maturing and releasing the virus to neighboring cells, tissues or organs before transmitting it between individuals. The influenza A virus has a vast and antigenically varied reservoir. In wild aquatic birds, the infection is typically asymptomatic. Avian influenza virus (AIV) can cross into new species, and occasionally it can acquire the ability to transmit from human to human. A pandemic might occur if a new influenza virus acquires enough adaptive mutations to maintain transmission between people. This review highlights the key determinants AIV must achieve to initiate a human pandemic and describes how AIV mutates to establish tropism and stable human adaptation. Understanding the tropism of AIV may be crucial in preventing virus transmission in humans and may help the design of vaccines, antivirals and therapeutic agents against the virus.
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Affiliation(s)
- Umarqayum AbuBakar
- Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Lina Amrani
- Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Farah Ayuni Kamarulzaman
- Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Saiful Anuar Karsani
- Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Pouya Hassandarvish
- Tropical Infectious Diseases Research and Education Center, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Jasmine Elanie Khairat
- Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
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Kumari R, Sharma SD, Kumar A, Ende Z, Mishina M, Wang Y, Falls Z, Samudrala R, Pohl J, Knight PR, Sambhara S. Antiviral Approaches against Influenza Virus. Clin Microbiol Rev 2023; 36:e0004022. [PMID: 36645300 PMCID: PMC10035319 DOI: 10.1128/cmr.00040-22] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Preventing and controlling influenza virus infection remains a global public health challenge, as it causes seasonal epidemics to unexpected pandemics. These infections are responsible for high morbidity, mortality, and substantial economic impact. Vaccines are the prophylaxis mainstay in the fight against influenza. However, vaccination fails to confer complete protection due to inadequate vaccination coverages, vaccine shortages, and mismatches with circulating strains. Antivirals represent an important prophylactic and therapeutic measure to reduce influenza-associated morbidity and mortality, particularly in high-risk populations. Here, we review current FDA-approved influenza antivirals with their mechanisms of action, and different viral- and host-directed influenza antiviral approaches, including immunomodulatory interventions in clinical development. Furthermore, we also illustrate the potential utility of machine learning in developing next-generation antivirals against influenza.
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Affiliation(s)
- Rashmi Kumari
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Department of Anesthesiology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Suresh D. Sharma
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Amrita Kumar
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Zachary Ende
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Oak Ridge Institute for Science and Education (ORISE), CDC Fellowship Program, Oak Ridge, Tennessee, USA
| | - Margarita Mishina
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Yuanyuan Wang
- Biotechnology Core Facility Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Association of Public Health Laboratories, Silver Spring, Maryland, USA
| | - Zackary Falls
- Department of Biomedical Informatics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Ram Samudrala
- Department of Biomedical Informatics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Jan Pohl
- Biotechnology Core Facility Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Paul R. Knight
- Department of Anesthesiology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Suryaprakash Sambhara
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Xu S, Zhang B, Yao J, Ruan W. A new H9 influenza virus mRNA vaccine elicits robust protective immunity against infection. Vaccine 2023; 41:2905-2913. [PMID: 37005103 DOI: 10.1016/j.vaccine.2023.03.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 04/03/2023]
Abstract
Avian influenza virus (AIV) poses a great threat to the poultry industry and public health. However commercial vaccines only provide limited immunity due to rapid virus mutation and rearrangement. Here, we developed an mRNA-lipid nanoparticle (mRNA-LNP) vaccine expressing AIV immunogenic protein hemagglutinin (HA) and also assessed its safety and immune-protection efficacy in vivo. Specifically, its safety was tested by inoculation of SPF chicken embryos and chicks, and there showed no clinical manifestations and pathological changes in both. As for the immune efficacy, the antibody titers, IFN-γ production levels, and viral loads in various organs were analyzed. The results showed that chickens in the mRNA-LNP-inoculated groups produced higher specific antibody titers compared with that in the control group by hemagglutination inhibition (HI) test. Meanwhile, the ELISpot assay demonstrated that the expression of IFN-γ was markedly induced in the mRNA-LNP group, and the viral loads in multiple organs were decreased. In addition, HE shows no obvious pathomorphological changes in the lungs of the mRNA-LNP-inoculated group. While, there was severe inflammatory cell infiltration in the DMEM-treated group instead. Taken together, the vaccine prepared in this study was safe and could trigger potent cellular and humoral immune response to defend against virus infection.
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Affiliation(s)
- Shengkui Xu
- Beijing Key Laboratory of Traditional Chinese Veterinary Medicine, College of Animal Science and Technology, Beijing University of Agriculture, Beijing 102206, People's Republic of China
| | - Bowen Zhang
- Beijing Key Laboratory of Traditional Chinese Veterinary Medicine, College of Animal Science and Technology, Beijing University of Agriculture, Beijing 102206, People's Republic of China
| | - Jielin Yao
- Beijing Key Laboratory of Traditional Chinese Veterinary Medicine, College of Animal Science and Technology, Beijing University of Agriculture, Beijing 102206, People's Republic of China
| | - Wenke Ruan
- Beijing Key Laboratory of Traditional Chinese Veterinary Medicine, College of Animal Science and Technology, Beijing University of Agriculture, Beijing 102206, People's Republic of China.
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Avian Influenza A Virus Polymerase Can Utilize Human ANP32 Proteins To Support cRNA but Not vRNA Synthesis. mBio 2023; 14:e0339922. [PMID: 36645303 PMCID: PMC9973007 DOI: 10.1128/mbio.03399-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Host restriction limits the emergence of novel pandemic strains from the influenza A virus avian reservoir. For efficient replication in mammalian cells, the avian influenza RNA-dependent RNA polymerase must adapt to use human orthologues of the host factor ANP32, which lack a 33-amino-acid insertion relative to avian ANP32A. Here, we find that influenza polymerase requires ANP32 proteins to support both steps of genome replication: cRNA and vRNA synthesis. However, avian strains are only restricted in vRNA synthesis in human cells. Therefore, avian influenza polymerase can use human ANP32 orthologues to support cRNA synthesis, without acquiring mammalian adaptations. This implies a fundamental difference in the mechanism by which ANP32 proteins support cRNA versus vRNA synthesis. IMPORTANCE To infect humans and cause a pandemic, avian influenza must first adapt to use human versions of the proteins the virus hijacks for replication, instead of the avian orthologues found in bird cells. One critical host protein is ANP32. Understanding the details of how host proteins such as ANP32 support viral activity may allow the design of new antiviral strategies that disrupt these interactions. Here, we use cells that lack ANP32 to unambiguously demonstrate ANP32 is needed for both steps of influenza genome replication. Unexpectedly, however, we found that avian influenza can use human ANP32 proteins for the first step of replication, to copy a complementary strand, without adaptation but can only utilize avian ANP32 for the second step of replication that generates new genomes. This suggests ANP32 may have a distinct role in supporting the second step of replication, and it is this activity that is specifically blocked when avian influenza infects human cells.
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The ubiquitination landscape of the influenza A virus polymerase. Nat Commun 2023; 14:787. [PMID: 36774438 PMCID: PMC9922279 DOI: 10.1038/s41467-023-36389-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 01/30/2023] [Indexed: 02/13/2023] Open
Abstract
During influenza A virus (IAV) infections, viral proteins are targeted by cellular E3 ligases for modification with ubiquitin. Here, we decipher and functionally explore the ubiquitination landscape of the IAV polymerase proteins during infection of human alveolar epithelial cells by applying mass spectrometry analysis of immuno-purified K-ε-GG (di-glycyl)-remnant-bearing peptides. We have identified 59 modified lysines across the three subunits, PB2, PB1 and PA of the viral polymerase of which 17 distinctively affect mRNA transcription, vRNA replication and the generation of recombinant viruses via non-proteolytic mechanisms. Moreover, further functional and in silico analysis indicate that ubiquitination at K578 in the PB1 thumb domain is mechanistically linked to dynamic structural transitions of the viral polymerase that are required for vRNA replication. Mutations K578A and K578R differentially affect the generation of recombinant viruses by impeding cRNA and vRNA synthesis, NP binding as well as polymerase dimerization. Collectively, our results demonstrate that the ubiquitin-mediated charge neutralization at PB1-K578 disrupts the interaction to an unstructured loop in the PB2 N-terminus that is required to coordinate polymerase dimerization and facilitate vRNA replication. This provides evidence that IAV exploits the cellular ubiquitin system to modulate the activity of the viral polymerase for viral replication.
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36
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Golin A, Tinkov AA, Aschner M, Farina M, da Rocha JBT. Relationship between selenium status, selenoproteins and COVID-19 and other inflammatory diseases: A critical review. J Trace Elem Med Biol 2023; 75:127099. [PMID: 36372013 PMCID: PMC9630303 DOI: 10.1016/j.jtemb.2022.127099] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/19/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022]
Abstract
The antioxidant effects of selenium as a component of selenoproteins has been thought to modulate host immunity and viral pathogenesis. Accordingly, the association of low dietary selenium status with inflammatory and immunodeficiency has been reported in the literature; however, the causal role of selenium deficiency in chronic inflammatory diseases and viral infection is still undefined. The COVID-19, characterized by acute respiratory syndrome and caused by the novel coronavirus 2, SARS-CoV-2, has infected millions of individuals worldwide since late 2019. The severity and mortality from COVID-19 have been associated with several factor, including age, sex and selenium deficiency. However, available data on selenium status and COVID-19 are limited, and a possible causative role for selenium deficiency in COVID-19 severity has yet to be fully addressed. In this context, we review the relationship between selenium, selenoproteins, COVID-19, immune and inflammatory responses, viral infection, and aging. Regardless of the role of selenium in immune and inflammatory responses, we emphasize that selenium supplementation should be indicated after a selenium deficiency be detected, particularly, in view of the critical role played by selenoproteins in human health. In addition, the levels of selenium should be monitored after the start of supplementation and discontinued as soon as normal levels are reached. Periodic assessment of selenium levels after supplementation is a critical issue to avoid over production of toxic metabolites of selenide because under normal conditions, selenoproteins attain saturated expression levels that limits their potential deleterious metabolic effects.
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Affiliation(s)
- Anieli Golin
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, RS, Brazil
| | - Alexey A Tinkov
- Yaroslavl State University, Yaroslavl, Russia; Institute of Cellular and Intracellular Symbiosis, Russian Academy of Sciences, Orenburg, Russia; Institute of Bioelementology, Orenburg, Russia
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - João Batista Teixeira da Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, RS, Brazil; Departamento de Bioquímica, Instituto Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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37
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A Review: The Antiviral Activity of Cyclic Peptides. Int J Pept Res Ther 2023; 29:7. [PMID: 36471676 PMCID: PMC9713128 DOI: 10.1007/s10989-022-10478-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2022] [Indexed: 12/02/2022]
Abstract
In the design and development of therapeutic agents, macromolecules with restricted structures have stronger competitive edges than linear biological entities since cyclization can overcome the limitations of linear structures. The common issues of linear peptides include susceptibility to degradation of the peptidase enzyme, off-target effects, and necessity of routine dosing, leading to instability and ineffectiveness. The unique conformational constraint of cyclic peptides provides a larger surface area to interact with the target at the same time, improving the membrane permeability and in vivo stability compared to their linear counterparts. Currently, cyclic peptides have been reported to possess various activities, such as antifungal, antiviral and antimicrobial activities. To date, there is emerging interest in cyclic peptide therapeutics, and increasing numbers of clinically approved cyclic peptide drugs are available on the market. In this review, the medical significance of cyclic peptides in the defence against viral infections will be highlighted. Except for chikungunya virus, which lacks specific antiviral treatment, all the viral diseases targeted in this review are those with effective treatments yet with certain limitations to date. Thus, strategies and approaches to optimise the antiviral effect of cyclic peptides will be discussed along with their respective outcomes. Apart from isolated naturally occurring cyclic peptides, chemically synthesized or modified cyclic peptides with antiviral activities targeting coronavirus, herpes simplex viruses, human immunodeficiency virus, Ebola virus, influenza virus, dengue virus, five main hepatitis viruses, termed as type A, B, C, D and E and chikungunya virus will be reviewed herein. Graphical Abstract
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Alternative splicing liberates a cryptic cytoplasmic isoform of mitochondrial MECR that antagonizes influenza virus. PLoS Biol 2022; 20:e3001934. [PMID: 36542656 PMCID: PMC9815647 DOI: 10.1371/journal.pbio.3001934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/05/2023] [Accepted: 11/29/2022] [Indexed: 12/24/2022] Open
Abstract
Viruses must balance their reliance on host cell machinery for replication while avoiding host defense. Influenza A viruses are zoonotic agents that frequently switch hosts, causing localized outbreaks with the potential for larger pandemics. The host range of influenza virus is limited by the need for successful interactions between the virus and cellular partners. Here we used immunocompetitive capture-mass spectrometry to identify cellular proteins that interact with human- and avian-style viral polymerases. We focused on the proviral activity of heterogenous nuclear ribonuclear protein U-like 1 (hnRNP UL1) and the antiviral activity of mitochondrial enoyl CoA-reductase (MECR). MECR is localized to mitochondria where it functions in mitochondrial fatty acid synthesis (mtFAS). While a small fraction of the polymerase subunit PB2 localizes to the mitochondria, PB2 did not interact with full-length MECR. By contrast, a minor splice variant produces cytoplasmic MECR (cMECR). Ectopic expression of cMECR shows that it binds the viral polymerase and suppresses viral replication by blocking assembly of viral ribonucleoprotein complexes (RNPs). MECR ablation through genome editing or drug treatment is detrimental for cell health, creating a generic block to virus replication. Using the yeast homolog Etr1 to supply the metabolic functions of MECR in MECR-null cells, we showed that specific antiviral activity is independent of mtFAS and is reconstituted by expressing cMECR. Thus, we propose a strategy where alternative splicing produces a cryptic antiviral protein that is embedded within a key metabolic enzyme.
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Pan M, Zhang W, Xiao Y, Lai Y, Cao M, Wang J, Deng T. The Hierarchical Sequence Requirements of the H1 Subtype-Specific Noncoding Regions of Influenza A Virus. Microbiol Spectr 2022; 10:e0315322. [PMID: 36287543 PMCID: PMC9769845 DOI: 10.1128/spectrum.03153-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 09/16/2022] [Indexed: 01/10/2023] Open
Abstract
The genome of influenza A virus consists of eight single-stranded viral RNA (vRNA) segments. The nonconserved noncoding regions (NCRs) at the 3' and 5' termini of each segment show extremely low divergence and mutation rate. They appear as segment specific among the eight segments and also subtype specific among different subtype-determinant hemagglutinin (HA) and neuraminidase (NA) segments. In order to acquire in-depth knowledge on the sequence requirements of the segment-specific or subtype-specific NCRs (ssNCRs), we, in the context of WSN (H1N1) reverse genetics, designed a virus random nucleotide selection assay (vRNSA) in which we generated pHW2000-HA plasmid libraries with random nucleotides in each grouped nucleotide positions in the 3' and 5' H1-ssNCRs, followed by virus rescue, serial passage, and deep sequencing. The resulting sequence logos present a visualized dynamic overview of the hierarchical sequence requirements of the 3' and 5' H1-ssNCRs. It showed that, in the process of continuous passage, the 3' H1-ssNCR, in general, stabilized more quickly than the 5' H1-ssNCR. The nucleotides close to the highly conserved 3' and 5' promoter regions showed higher sequence stringency than nucleotides away from the promoter regions. All stabilized sequences displayed a common feature of high A/U ratios. Especially with our mutational function analyses, we demonstrate that the 3' promoter-proximal nucleotides could cooperatively exert a direct effect on the transcription and replication of the HA segment. Together, these results provide in-depth knowledge for understanding the NCRs of influenza A virus. IMPORTANCE The segment-specific and subtype-specific nonconserved noncoding regions (ssNCRs) at both 3' and 5' ends of viral RNA segments of influenza A virus are largely conserved among the same segments of different viruses. However, the function-related sequence requirements of these ssNCRs remain unclear. In this study, through a novel self-designed vRNSA approach, we present a visualized dynamic overview diagram directly reflecting the hierarchical sequence requirements within and between the 3' and 5' H1-ssNCRs. The in-depth functional mutagenesis analyses further revealed that specific nucleotides in the 3' promoter-proximal region could cooperatively exert a direct effect on viral RNA transcription and replication. This work further advanced our knowledge in understanding the nonconserved noncoding regions of influenza A viruses.
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Affiliation(s)
- Minglei Pan
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wenyu Zhang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yue Xiao
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuerong Lai
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Mengmeng Cao
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jianwei Wang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tao Deng
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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40
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French H, Pitré E, Oade MS, Elshina E, Bisht K, King A, Bauer DL, te Velthuis AJ. Transient RNA structures cause aberrant influenza virus replication and innate immune activation. SCIENCE ADVANCES 2022; 8:eabp8655. [PMID: 36083899 PMCID: PMC9462681 DOI: 10.1126/sciadv.abp8655] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 07/26/2022] [Indexed: 05/06/2023]
Abstract
During infection, the influenza A virus RNA polymerase produces both full-length and aberrant RNA molecules, such as defective viral genomes (DVGs) and mini viral RNAs (mvRNAs). Subsequent innate immune activation involves the binding of host pathogen receptor retinoic acid-inducible gene I (RIG-I) to viral RNAs. However, it is not clear what factors determine which influenza A virus RNAs are RIG-I agonists. Here, we provide evidence that RNA structures, called template loops (t-loops), stall the viral RNA polymerase and contribute to innate immune activation by mvRNAs during influenza A virus infection. Impairment of replication by t-loops depends on the formation of an RNA duplex near the template entry and exit channels of the RNA polymerase, and this effect is enhanced by mutation of the template exit path from the RNA polymerase active site. Overall, these findings are suggestive of a mechanism involving polymerase stalling that links aberrant viral replication to the activation of the innate immune response.
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Affiliation(s)
- Hollie French
- University of Cambridge, Department of Pathology, Addenbrooke’s Hospital, Cambridge CB2 2QQ, UK
| | - Emmanuelle Pitré
- University of Cambridge, Department of Pathology, Addenbrooke’s Hospital, Cambridge CB2 2QQ, UK
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Michael S. Oade
- University of Cambridge, Department of Pathology, Addenbrooke’s Hospital, Cambridge CB2 2QQ, UK
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Elizaveta Elshina
- University of Cambridge, Department of Pathology, Addenbrooke’s Hospital, Cambridge CB2 2QQ, UK
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Karishma Bisht
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Alannah King
- University of Cambridge, Department of Pathology, Addenbrooke’s Hospital, Cambridge CB2 2QQ, UK
| | - David L.V. Bauer
- RNA Virus Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Aartjan J.W. te Velthuis
- University of Cambridge, Department of Pathology, Addenbrooke’s Hospital, Cambridge CB2 2QQ, UK
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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Jakob C, Paul-Stansilaus R, Schwemmle M, Marquet R, Bolte H. The influenza A virus genome packaging network - complex, flexible and yet unsolved. Nucleic Acids Res 2022; 50:9023-9038. [PMID: 35993811 PMCID: PMC9458418 DOI: 10.1093/nar/gkac688] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/19/2022] [Accepted: 08/18/2022] [Indexed: 12/24/2022] Open
Abstract
The genome of influenza A virus (IAV) consists of eight unique viral RNA segments. This genome organization allows genetic reassortment between co-infecting IAV strains, whereby new IAVs with altered genome segment compositions emerge. While it is known that reassortment events can create pandemic IAVs, it remains impossible to anticipate reassortment outcomes with pandemic prospects. Recent research indicates that reassortment is promoted by a viral genome packaging mechanism that delivers the eight genome segments as a supramolecular complex into the virus particle. This finding holds promise of predicting pandemic IAVs by understanding the intermolecular interactions governing this genome packaging mechanism. Here, we critically review the prevailing mechanistic model postulating that IAV genome packaging is orchestrated by a network of intersegmental RNA-RNA interactions. Although we find supporting evidence, including segment-specific packaging signals and experimentally proposed RNA-RNA interaction networks, this mechanistic model remains debatable due to a current shortage of functionally validated intersegmental RNA-RNA interactions. We speculate that identifying such functional intersegmental RNA-RNA contacts might be hampered by limitations of the utilized probing techniques and the inherent complexity of the genome packaging mechanism. Nevertheless, we anticipate that improved probing strategies combined with a mutagenesis-based validation could facilitate their discovery.
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Affiliation(s)
| | | | - Martin Schwemmle
- To whom correspondence should be addressed. Tel: +49 761 203 6526; Fax: +49 761 203 6626;
| | - Roland Marquet
- Correspondence may also be addressed to Roland Marquet. Tel: +33 3 88 41 70 54; Fax: +33 3 88 60 22 18;
| | - Hardin Bolte
- Institute of Virology, Medical Center – University of Freiburg, 79104 Freiburg, Germany,Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
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Yip AJW, Low ZY, Chow VTK, Lal SK. Repurposing Molnupiravir for COVID-19: The Mechanisms of Antiviral Activity. Viruses 2022; 14:v14061345. [PMID: 35746815 PMCID: PMC9228778 DOI: 10.3390/v14061345] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 06/09/2022] [Accepted: 06/17/2022] [Indexed: 12/14/2022] Open
Abstract
Molnupiravir is a β-d-N4-hydroxycytidine-5'-isopropyl ester (NHC) compound that exerts antiviral activity against various RNA viruses such as influenza, SARS, and Ebola viruses. Thus, the repurposing of Molnupiravir has gained significant attention for combatting infection with SARS-CoV-2, the etiological agent of COVID-19. Recently, Molnupiravir was granted authorization for the treatment of mild-to-moderate COVID-19 in adults. Findings from in vitro experiments, in vivo studies and clinical trials reveal that Molnupiravir is effective against SARS-CoV-2 by inducing viral RNA mutagenesis, thereby giving rise to mutated complementary RNA strands that generate non-functional viruses. To date, the data collectively suggest that Molnupiravir possesses promising antiviral activity as well as favorable prophylactic efficacy, attributed to its effective mutagenic property of disrupting viral replication. This review discusses the mechanisms of action of Molnupiravir and highlights its clinical utility by disabling SARS-CoV-2 replication, thereby ameliorating COVID-19 severity. Despite relatively few short-term adverse effects thus far, further detailed clinical studies and long-term pharmacovigilance are needed in view of its mutagenic effects.
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Affiliation(s)
- Ashley Jia Wen Yip
- School of Science, Monash University, Bandar Sunway, Subang Jaya 47500, Selangor Darul Ehsan, Malaysia; (A.J.W.Y.); (Z.Y.L.)
| | - Zheng Yao Low
- School of Science, Monash University, Bandar Sunway, Subang Jaya 47500, Selangor Darul Ehsan, Malaysia; (A.J.W.Y.); (Z.Y.L.)
| | - Vincent T. K. Chow
- Infectious Diseases Translational Research Program, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore;
| | - Sunil K. Lal
- School of Science, Monash University, Bandar Sunway, Subang Jaya 47500, Selangor Darul Ehsan, Malaysia; (A.J.W.Y.); (Z.Y.L.)
- Tropical Medicine & Biology Platform, Monash University, Subang Jaya 47500, Selangor Darul Ehsan, Malaysia
- Correspondence:
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Wang F, Sheppard CM, Mistry B, Staller E, Barclay WS, Grimes JM, Fodor E, Fan H. The C-terminal LCAR of host ANP32 proteins interacts with the influenza A virus nucleoprotein to promote the replication of the viral RNA genome. Nucleic Acids Res 2022; 50:5713-5725. [PMID: 35639917 PMCID: PMC9177957 DOI: 10.1093/nar/gkac410] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 04/11/2022] [Accepted: 05/09/2022] [Indexed: 12/12/2022] Open
Abstract
The segmented negative-sense RNA genome of influenza A virus is assembled into ribonucleoprotein complexes (RNP) with viral RNA-dependent RNA polymerase and nucleoprotein (NP). It is in the context of these RNPs that the polymerase transcribes and replicates viral RNA (vRNA). Host acidic nuclear phosphoprotein 32 (ANP32) family proteins play an essential role in vRNA replication by mediating the dimerization of the viral polymerase via their N-terminal leucine-rich repeat (LRR) domain. However, whether the C-terminal low-complexity acidic region (LCAR) plays a role in RNA synthesis remains unknown. Here, we report that the LCAR is required for viral genome replication during infection. Specifically, we show that the LCAR directly interacts with NP and this interaction is mutually exclusive with RNA. Furthermore, we show that the replication of a short vRNA-like template that can be replicated in the absence of NP is less sensitive to LCAR truncations compared with the replication of full-length vRNA segments which is NP-dependent. We propose a model in which the LCAR interacts with NP to promote NP recruitment to nascent RNA during influenza virus replication, ensuring the co-replicative assembly of RNA into RNPs.
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Affiliation(s)
- Fangzheng Wang
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Carol M Sheppard
- Department of Infectious Disease, Faculty of Medicine, Imperial College, London, UK
| | - Bhakti Mistry
- Department of Infectious Disease, Faculty of Medicine, Imperial College, London, UK
| | - Ecco Staller
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.,Department of Infectious Disease, Faculty of Medicine, Imperial College, London, UK
| | - Wendy S Barclay
- Department of Infectious Disease, Faculty of Medicine, Imperial College, London, UK
| | - Jonathan M Grimes
- Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Oxford, UK.,Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, UK
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Haitian Fan
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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Diefenbacher M, Tan TJC, Bauer DLV, Stadtmueller BM, Wu NC, Brooke CB. Interactions between Influenza A Virus Nucleoprotein and Gene Segment Untranslated Regions Facilitate Selective Modulation of Viral Gene Expression. J Virol 2022; 96:e0020522. [PMID: 35467364 PMCID: PMC9131868 DOI: 10.1128/jvi.00205-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/29/2022] [Indexed: 11/20/2022] Open
Abstract
The influenza A virus (IAV) genome is divided into eight negative-sense, single-stranded RNA segments. Each segment exhibits a unique level and temporal pattern of expression; however, the exact mechanisms underlying the patterns of individual gene segment expression are poorly understood. We previously demonstrated that a single substitution in the viral nucleoprotein (NP:F346S) selectively modulates neuraminidase (NA) gene segment expression while leaving other segments largely unaffected. Given what is currently known about NP function, there is no obvious explanation for how changes in NP can selectively modulate the replication of individual gene segments. In this study, we found that the specificity of this effect for the NA segment is virus strain specific and depends on the untranslated region (UTR) sequences of the NA segment. While the NP:F346S substitution did not significantly alter the RNA binding or oligomerization activities of NP in vitro, it specifically decreased the ability of NP to promote NA segment viral RNA (vRNA) synthesis. In addition to NP residue F346, we identified two other adjacent aromatic residues in NP (Y385 and F479) capable of similarly regulating NA gene segment expression, suggesting a larger role for this domain in gene-segment specific regulation. Our findings reveal a novel role for NP in selective regulation of viral gene segment replication and provide a framework for understanding how the expression patterns of individual viral gene segments can be modulated during adaptation to new host environments. IMPORTANCE Influenza A virus (IAV) is a respiratory pathogen that remains a significant source of morbidity and mortality. Escape from host immunity or emergence into new host species often requires mutations that modulate the functional activities of the viral glycoproteins hemagglutinin (HA) and neuraminidase (NA), which are responsible for virus attachment to and release from host cells, respectively. Maintaining the functional balance between the activities of HA and NA is required for fitness across multiple host systems. Thus, selective modulation of viral gene expression patterns may be a key determinant of viral immune escape and cross-species transmission potential. We identified a novel mechanism by which the viral nucleoprotein (NP) gene can selectively modulate NA segment replication and gene expression through interactions with the segment UTRs. Our work highlights an unexpected role for NP in selective regulation of expression from the individual IAV gene segments.
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Affiliation(s)
- Meghan Diefenbacher
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Timothy J. C. Tan
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - David L. V. Bauer
- RNA Virus Replication Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Beth M. Stadtmueller
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Biomedical and Translational Sciences, Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Nicholas C. Wu
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Biomedical and Translational Sciences, Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Christopher B. Brooke
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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G Protein Subunit β1 Facilitates Influenza A Virus Replication by Promoting the Nuclear Import of PB2. J Virol 2022; 96:e0049422. [PMID: 35604143 DOI: 10.1128/jvi.00494-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
G protein subunit β1 (GNB1), the beta subunit of the G protein family, plays an important role in regulating transmembrane signal transduction. Although a recent study has demonstrated that GNB1 can bind the matrix protein 1 (M1) to facilitate M1 transport to budding sites and promote the release of progeny influenza A virus (IAV), whether the GNB1 protein has other functions in IAV replication requires further study. Here, we found that GNB1 promoted IAV replication, as virus yield decreased in GNB1 knockdown or knockout cells. GNB1 interacted with polymerase subunits PB2, PB1, and PA. Overexpressed GNB1 facilitated PB2 binding to importin α3, α5, and α7 promoting the nuclear import of PB2, enhancing viral RNA synthesis and polymerase activity. Altogether, our results demonstrated that GNB1 positively regulates virus replication by interacting with polymerase subunits and facilitating the nuclear import of PB2, which provide novel insights into the molecular mechanism of IAV. IMPORTANCE Until now, there has been only one article on the role of GNB1 in IAV budding. No study has investigated the role of GNB1 in IAV replication. In this study, our research demonstrated that GNB1 could increase the interaction between PB2 and the importin α isoform and mediate the nuclear import of PB2. Therefore, GNB1 could promote viral replication and transcription. Our results provide a better understanding of the molecular mechanisms of viral replication and provide potential antiviral drug targets.
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Hou L, Zhang Y, Ju H, Cherukupalli S, Jia R, Zhang J, Huang B, Loregian A, Liu X, Zhan P. Contemporary medicinal chemistry strategies for the discovery and optimization of influenza inhibitors targeting vRNP constituent proteins. Acta Pharm Sin B 2022; 12:1805-1824. [PMID: 35847499 PMCID: PMC9279641 DOI: 10.1016/j.apsb.2021.11.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 11/02/2021] [Accepted: 11/12/2021] [Indexed: 11/21/2022] Open
Abstract
Influenza is an acute respiratory infectious disease caused by the influenza virus, affecting people globally and causing significant social and economic losses. Due to the inevitable limitations of vaccines and approved drugs, there is an urgent need to discover new anti-influenza drugs with different mechanisms. The viral ribonucleoprotein complex (vRNP) plays an essential role in the life cycle of influenza viruses, representing an attractive target for drug design. In recent years, the functional area of constituent proteins in vRNP are widely used as targets for drug discovery, especially the PA endonuclease active site, the RNA-binding site of PB1, the cap-binding site of PB2 and the nuclear export signal of NP protein. Encouragingly, the PA inhibitor baloxavir has been marketed in Japan and the United States, and several drug candidates have also entered clinical trials, such as favipiravir. This article reviews the compositions and functions of the influenza virus vRNP and the research progress on vRNP inhibitors, and discusses the representative drug discovery and optimization strategies pursued.
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Yu M, Sun L, Zhang Z, Zhang Y, Zhang H, Na L, Wang X. KPNA6 is a Cofactor of ANP32A/B in Supporting Influenza Virus Polymerase Activity. Microbiol Spectr 2022; 10:e0207321. [PMID: 35044222 PMCID: PMC8768627 DOI: 10.1128/spectrum.02073-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 12/20/2021] [Indexed: 11/25/2022] Open
Abstract
Influenza A virus (IAV) RNA-dependent RNA polymerase (vPol) is a heterotrimer composed of PB2, PB1, and PA, which, together with vRNA and nucleoprotein (NP), forms viral ribonucleoprotein (vRNP) complex to direct the transcription and replication of the viral genome. Host factor ANP32 proteins have been proved to be associated with vRNP and are essential for polymerase activity and cross-species restriction of avian influenza virus. However, the molecular mechanism by which ANP32 supports polymerase activity is largely unknown. Here, we identified that KPNA6 is associated with ANP32A/B and vRNP of the influenza virus. Both knockout and overexpression of KPNA6 downregulate the replication of the influenza virus by inhibiting the polymerase activity, indicating that a certain level of KPNA6 is beneficial for efficient replication of the influenza virus. Furthermore, we demonstrate that overexpression of KPNA6 or its nuclear importing domain negative mutation inhibited the interaction between ANP32 and vRNP, thus reducing the polymerase activity. Our results revealed the role of KPNA6 in interacting with both ANP32A/B and vRNP to maintain viral polymerase activity and provided new insights for further understanding of the mechanism by which ANP32 supports influenza polymerase. IMPORTANCE Host factor ANP32 plays a fundamental role in supporting the polymerase activity of influenza viruses, but the underlying mechanism is largely unknown. Here, we propose that KPNA6 is involved in the function of ANP32A/B to support influenza virus polymerase by interacting with both vRNP and ANP32A/B. The proper amount of KPNA6 and ANP32 proteins in the KPNA6-ANP32-vRNP complex is crucial for maintaining the viral polymerase activity. The KPNA6 may contribute to maintaining stable interaction between vRNA and ANP32 proteins in the nucleus, and this function is independent of the known importing domain of KPNA6. Our research reveals a role of KNPA6 associated with ANP32 proteins that support the viral polymerase and suggests a new perspective for developing antiviral strategies.
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Affiliation(s)
- Mengmeng Yu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Liuke Sun
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhenyu Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yuan Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Haili Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Lei Na
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiaojun Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
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The C-terminal domains of the PB2 subunit of the influenza A virus RNA polymerase directly interact with cellular GTPase Rab11a. J Virol 2022; 96:e0197921. [PMID: 35019720 PMCID: PMC8906434 DOI: 10.1128/jvi.01979-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Influenza A virus (IAV) contains a segmented RNA genome that is transcribed and replicated by the viral RNA polymerase in the cell nucleus. Replicated RNA segments are assembled with viral polymerase and oligomeric nucleoprotein into viral ribonucleoprotein (vRNP) complexes which are exported from the nucleus and transported across the cytoplasm to be packaged into progeny virions. Host GTPase Rab11a associated with recycling endosomes is believed to contribute to this process by mediating the cytoplasmic transport of vRNPs. However, how vRNPs interact with Rab11a remains poorly understood. In this study, we utilised a combination of biochemical, proteomic, and biophysical approaches to characterise the interaction between the viral polymerase and Rab11a. Using pull-down assays we show that vRNPs but not cRNPs from infected cell lysates bind to Rab11a. We also show that the viral polymerase directly interacts with Rab11a and that the C-terminal two thirds of the PB2 polymerase subunit (PB2-C) comprising the cap-binding, mid-link, 627 and nuclear localization signal (NLS) domains mediate this interaction. Small-angle X-ray scattering (SAXS) experiments confirmed that PB2-C associates with Rab11a in solution forming a compact folded complex with a 1:1 stoichiometry. Furthermore, we demonstrate that the switch I region of Rab11a, that has been shown to be important for binding Rab11 family interacting proteins (Rab11-FIPs), is also important for PB2-C binding suggesting that IAV polymerase and Rab11-FIPs compete for the same binding site. Our findings expand our understanding of the interaction between the IAV polymerase and Rab11a in the cytoplasmic transport of vRNPs. Importance The influenza virus RNA genome segments are replicated in the cell nucleus and are assembled into viral ribonucleoprotein (vRNP) complexes with viral RNA polymerase and nucleoprotein (NP). Replicated vRNPs need to be exported from the nucleus and trafficked across the cytoplasm to the cell membrane where virion assembly takes place. The host GTPase Rab11a plays a role in vRNP trafficking. In this study we show that the viral polymerase directly interacts with Rab11a mediating the interaction between vRNPs and Rab11a. We map this interaction to the C-terminal domains of the PB2 polymerase subunit and the switch I region of Rab11a. Identifying the exact site of Rab11a binding on the viral polymerase could uncover a novel target site for the development of an influenza antiviral drug.
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Mapping inhibitory sites on the RNA polymerase of the 1918 pandemic influenza virus using nanobodies. Nat Commun 2022; 13:251. [PMID: 35017564 PMCID: PMC8752864 DOI: 10.1038/s41467-021-27950-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 12/21/2021] [Indexed: 11/26/2022] Open
Abstract
Influenza A viruses cause seasonal epidemics and global pandemics, representing a considerable burden to healthcare systems. Central to the replication cycle of influenza viruses is the viral RNA-dependent RNA polymerase which transcribes and replicates the viral RNA genome. The polymerase undergoes conformational rearrangements and interacts with viral and host proteins to perform these functions. Here we determine the structure of the 1918 influenza virus polymerase in transcriptase and replicase conformations using cryo-electron microscopy (cryo-EM). We then structurally and functionally characterise the binding of single-domain nanobodies to the polymerase of the 1918 pandemic influenza virus. Combining these functional and structural data we identify five sites on the polymerase which are sensitive to inhibition by nanobodies. We propose that the binding of nanobodies at these sites either prevents the polymerase from assuming particular functional conformations or interactions with viral or host factors. The polymerase is highly conserved across the influenza A subtypes, suggesting these sites as effective targets for potential influenza antiviral development. Influenza viruses carry their own RNAdependent RNA-polymerase that is highly conserved and a promising anti-viral target. Combining functional and structural data, Keown et al. characterise the inhibitory effect of nanobodies on 1918 pandemic H1N1 influenza strain polymerase complex and identify sensitive sites interfering with polymerase activity in vitro.
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50
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Abstract
Influenza A viruses are negative-sense RNA viruses that rely on their own viral replication machinery to replicate and transcribe their segmented single-stranded RNA genome. The viral ribonucleoprotein complexes in which viral RNA is replicated consist of a nucleoprotein scaffold around which the RNA genome is bound, and a heterotrimeric RNA-dependent RNA polymerase that catalyzes viral replication. The RNA polymerase copies the viral RNA (vRNA) via a replicative intermediate, called the complementary RNA (cRNA), and subsequently uses this cRNA to make more vRNA copies. To ensure that new cRNA and vRNA molecules are associated with ribonucleoproteins in which they can be amplified, the active RNA polymerase recruits a second polymerase to encapsidate the cRNA or vRNA. Host factor ANP32A has been shown to be essential for viral replication and to facilitate the formation of a dimer between viral RNA polymerases. Differences between mammalian and avian ANP32A proteins are sufficient to restrict viral replication. It has been proposed that ANP32A is only required for the synthesis of vRNA molecules from a cRNA, but not vice versa. However, this view does not match recent molecular evidence. Here we use minigenome assays, virus infections, and viral promoter mutations to demonstrate that ANP32A is essential for both vRNA and cRNA synthesis. Moreover, we show that ANP32 is not only needed for the actively replicating polymerase, but also for the polymerase that is encapsidating nascent viral RNA products. Overall, these results provide new insights into influenza A virus replication and host adaptation. IMPORTANCE Zoonotic avian influenza A viruses pose a constant threat to global health, and they have the potential to cause pandemics. Species variations in host factor ANP32A play a key role in supporting the activity of avian influenza A virus RNA polymerases in mammalian hosts. Here we show that ANP32A acts at two stages in the influenza A virus replication cycle, supporting recent structural experiments, in line with its essential role. Understanding how ANP32A supports viral RNA polymerase activity and how it supports avian polymerase function in mammalian hosts is important for understanding influenza A virus replication and the development of antiviral strategies against influenza A viruses.
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