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Khalil AM, Nogales A, Martínez-Sobrido L, Mostafa A. Antiviral responses versus virus-induced cellular shutoff: a game of thrones between influenza A virus NS1 and SARS-CoV-2 Nsp1. Front Cell Infect Microbiol 2024; 14:1357866. [PMID: 38375361 PMCID: PMC10875036 DOI: 10.3389/fcimb.2024.1357866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 01/16/2024] [Indexed: 02/21/2024] Open
Abstract
Following virus recognition of host cell receptors and viral particle/genome internalization, viruses replicate in the host via hijacking essential host cell machinery components to evade the provoked antiviral innate immunity against the invading pathogen. Respiratory viral infections are usually acute with the ability to activate pattern recognition receptors (PRRs) in/on host cells, resulting in the production and release of interferons (IFNs), proinflammatory cytokines, chemokines, and IFN-stimulated genes (ISGs) to reduce virus fitness and mitigate infection. Nevertheless, the game between viruses and the host is a complicated and dynamic process, in which they restrict each other via specific factors to maintain their own advantages and win this game. The primary role of the non-structural protein 1 (NS1 and Nsp1) of influenza A viruses (IAV) and the pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), respectively, is to control antiviral host-induced innate immune responses. This review provides a comprehensive overview of the genesis, spatial structure, viral and cellular interactors, and the mechanisms underlying the unique biological functions of IAV NS1 and SARS-CoV-2 Nsp1 in infected host cells. We also highlight the role of both non-structural proteins in modulating viral replication and pathogenicity. Eventually, and because of their important role during viral infection, we also describe their promising potential as targets for antiviral therapy and the development of live attenuated vaccines (LAV). Conclusively, both IAV NS1 and SARS-CoV-2 Nsp1 play an important role in virus-host interactions, viral replication, and pathogenesis, and pave the way to develop novel prophylactic and/or therapeutic interventions for the treatment of these important human respiratory viral pathogens.
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Affiliation(s)
- Ahmed Magdy Khalil
- Disease Intervention & Prevention and Host Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, TX, United States
- Department of Zoonotic Diseases, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Aitor Nogales
- Center for Animal Health Research, CISA-INIA-CSIC, Madrid, Spain
| | - Luis Martínez-Sobrido
- Disease Intervention & Prevention and Host Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Ahmed Mostafa
- Disease Intervention & Prevention and Host Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, TX, United States
- Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza, Egypt
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2
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Alasiri A, Soltane R, Hegazy A, Khalil AM, Mahmoud SH, Khalil AA, Martinez-Sobrido L, Mostafa A. Vaccination and Antiviral Treatment against Avian Influenza H5Nx Viruses: A Harbinger of Virus Control or Evolution. Vaccines (Basel) 2023; 11:1628. [PMID: 38005960 PMCID: PMC10675773 DOI: 10.3390/vaccines11111628] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/11/2023] [Accepted: 10/20/2023] [Indexed: 11/26/2023] Open
Abstract
Despite the panzootic nature of emergent highly pathogenic avian influenza H5Nx viruses in wild migratory birds and domestic poultry, only a limited number of human infections with H5Nx viruses have been identified since its emergence in 1996. Few countries with endemic avian influenza viruses (AIVs) have implemented vaccination as a control strategy, while most of the countries have adopted a culling strategy for the infected flocks. To date, China and Egypt are the two major sites where vaccination has been adopted to control avian influenza H5Nx infections, especially with the widespread circulation of clade 2.3.4.4b H5N1 viruses. This virus is currently circulating among birds and poultry, with occasional spillovers to mammals, including humans. Herein, we will discuss the history of AIVs in Egypt as one of the hotspots for infections and the improper implementation of prophylactic and therapeutic control strategies, leading to continuous flock outbreaks with remarkable virus evolution scenarios. Along with current pre-pandemic preparedness efforts, comprehensive surveillance of H5Nx viruses in wild birds, domestic poultry, and mammals, including humans, in endemic areas is critical to explore the public health risk of the newly emerging immune-evasive or drug-resistant H5Nx variants.
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Affiliation(s)
- Ahlam Alasiri
- Department of Basic Sciences, Adham University College, Umm Al-Qura University, Makkah 21955, Saudi Arabia; (A.A.); (R.S.)
| | - Raya Soltane
- Department of Basic Sciences, Adham University College, Umm Al-Qura University, Makkah 21955, Saudi Arabia; (A.A.); (R.S.)
| | - Akram Hegazy
- Department of Agricultural Microbiology, Faculty of Agriculture, Cairo University, Giza District, Giza 12613, Egypt;
| | - Ahmed Magdy Khalil
- Texas Biomedical Research Institute, San Antonio, TX 78227, USA;
- Department of Zoonotic Diseases, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44519, Egypt
| | - Sara H. Mahmoud
- Center of Scientific Excellence for Influenza Viruses, National Research Center, Giza 12622, Egypt;
| | - Ahmed A. Khalil
- Veterinary Sera and Vaccines Research Institute (VSVRI), Agriculture Research Center (ARC), Cairo 11435, Egypt;
| | | | - Ahmed Mostafa
- Texas Biomedical Research Institute, San Antonio, TX 78227, USA;
- Center of Scientific Excellence for Influenza Viruses, National Research Center, Giza 12622, Egypt;
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3
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Blake ME, Kleinpeter AB, Jureka AS, Petit CM. Structural Investigations of Interactions between the Influenza a Virus NS1 and Host Cellular Proteins. Viruses 2023; 15:2063. [PMID: 37896840 PMCID: PMC10612106 DOI: 10.3390/v15102063] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
The Influenza A virus is a continuous threat to public health that causes yearly epidemics with the ever-present threat of the virus becoming the next pandemic. Due to increasing levels of resistance, several of our previously used antivirals have been rendered useless. There is a strong need for new antivirals that are less likely to be susceptible to mutations. One strategy to achieve this goal is structure-based drug development. By understanding the minute details of protein structure, we can develop antivirals that target the most conserved, crucial regions to yield the highest chances of long-lasting success. One promising IAV target is the virulence protein non-structural protein 1 (NS1). NS1 contributes to pathogenicity through interactions with numerous host proteins, and many of the resulting complexes have been shown to be crucial for virulence. In this review, we cover the NS1-host protein complexes that have been structurally characterized to date. By bringing these structures together in one place, we aim to highlight the strength of this field for drug discovery along with the gaps that remain to be filled.
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Affiliation(s)
| | | | | | - Chad M. Petit
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (M.E.B.)
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Griffin EF, Tompkins SM. Fitness Determinants of Influenza A Viruses. Viruses 2023; 15:1959. [PMID: 37766365 PMCID: PMC10535923 DOI: 10.3390/v15091959] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
Influenza A (IAV) is a major human respiratory pathogen that causes illness, hospitalizations, and mortality annually worldwide. IAV is also a zoonotic pathogen with a multitude of hosts, allowing for interspecies transmission, reassortment events, and the emergence of novel pandemics, as was seen in 2009 with the emergence of a swine-origin H1N1 (pdmH1N1) virus into humans, causing the first influenza pandemic of the 21st century. While the 2009 pandemic was considered to have high morbidity and low mortality, studies have linked the pdmH1N1 virus and its gene segments to increased disease in humans and animal models. Genetic components of the pdmH1N1 virus currently circulate in the swine population, reassorting with endemic swine viruses that co-circulate and occasionally spillover into humans. This is evidenced by the regular detection of variant swine IAVs in humans associated with state fairs and other intersections of humans and swine. Defining genetic changes that support species adaptation, virulence, and cross-species transmission, as well as mutations that enhance or attenuate these features, will improve our understanding of influenza biology. It aids in surveillance and virus risk assessment and guides the establishment of counter measures for emerging viruses. Here, we review the current understanding of the determinants of specific IAV phenotypes, focusing on the fitness, transmission, and virulence determinants that have been identified in swine IAVs and/or in relation to the 2009 pdmH1N1 virus.
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Affiliation(s)
- Emily Fate Griffin
- Center for Vaccines and Immunology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
- Emory-UGA Centers of Excellence for Influenza Research and Surveillance (CEIRS), Athens, GA 30602, USA
| | - Stephen Mark Tompkins
- Center for Vaccines and Immunology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
- Emory-UGA Centers of Excellence for Influenza Research and Surveillance (CEIRS), Athens, GA 30602, USA
- Center for Influenza Disease and Emergence Response (CIDER), Athens, GA 30602, USA
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Mashaal D, Mahmoud SH, Müller C, Abo Shama NM, Kamer AA, Abdelaziz AA, Ali MA, Pleschka S, Mostafa A. Differential Impact of Specific Amino Acid Residues on the Characteristics of Avian Influenza Viruses in Mammalian Systems. Pathogens 2022; 11:1385. [PMID: 36422635 PMCID: PMC9698692 DOI: 10.3390/pathogens11111385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/11/2022] [Accepted: 11/18/2022] [Indexed: 11/26/2023] Open
Abstract
Avian influenza virus (AIV) H9N2 was declared to be endemic in birds of the Middle East, in particular in Egypt, with multiple cases of human infections. Despite concerns about the pandemic threat posed by H9N2 AIV, due to the fact that its receptor specificity is similar to that of human influenza viruses, its morbidity and mortality rates in humans are so far negligible. However, the acquisition of specific adaptive amino acid (aa) mutations in the viral polymerase can enhance cross-species transmission of the virus itself or of reassortants, which gained these changes. The polymerase basic protein 2 (PB2) is one of the key determinants for AIV adaptation towards mammals. Although mammalian pathogenicity-related mutations (MPMs) in PB2 genes were identified in different AIVs, the specific effect of single or multiple mutations on viral fitness has not been compared so far. Here, we studied the effect of the aa K at position 591, which was frequently reported in the PB2 of Egyptian H9N2 isolates, on the proliferation efficiency and polymerase activity of an H5N1 (clade 2.2.1.2) AIV already carrying the mammalian adaptive mutation 627K. Using reverse genetics, we generated a set of recombinant parental strains and H5N1 variants carrying the avian-like 591Q/627E or mammalian-like adaptive mutations 591K/627K (H5N1EGY, H9N2EGY, H5N1PB2-H9N2EGY, H5N1H9N2_PB2_K591Q, H5N1PB2_K627E, H5N1PB2_K627E/591K, H5N1PB2_627K/591K). Regardless of the avian-like 627E or the mammalian-adaptive 627K, both variants carrying the 591K (H5N1PB2_K627E/591K, H5N1PB2_627K/591K) and the reassortant H5N1PB2-H9N2EGY replicated to significantly higher levels in mammalian continuous MDCK and Calu-3 cell lines and primary normal human bronchial epithelial cells than the parental H5N1EGY virus (carrying solely the 627K adaptive mutation). Expectedly, the H5N1 variants carrying avian-like PB2 mutations (H5N1H9N2_PB2_K591Q, H5N1PB2_K627E) replicated to significantly lower levels than the parental H5N1EGY virus in the predefined primary and continuous mammalian cell line systems. Consistently, the activity of H5N1 subtype AIV polymerase complexes comprising PB2 segments with singular 591K or combined with 627K was significantly enhanced when compared to parental H5N1EGY and H9N2EGY. This study emphasizes the significant impact of 591K containing PB2 segments in the background of H5N1 polymerase on viral fitness in addition to the well-known MPM 627K in vitro.
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Affiliation(s)
- Dayly Mashaal
- Pharmaceutical Microbiology Department, Faculty of Pharmacy, Tanta University, Tanta 31527, Egypt
| | - Sara H Mahmoud
- Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza 12622, Egypt
| | - Christin Müller
- Institute of Medical Virology, Justus Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany
| | - Noura M Abo Shama
- Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza 12622, Egypt
| | - Amal Abo Kamer
- Pharmaceutical Microbiology Department, Faculty of Pharmacy, Tanta University, Tanta 31527, Egypt
| | - Ahmed A Abdelaziz
- Pharmaceutical Microbiology Department, Faculty of Pharmacy, Tanta University, Tanta 31527, Egypt
| | - Mohamed A Ali
- Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza 12622, Egypt
| | - Stephan Pleschka
- Institute of Medical Virology, Justus Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany
- German Center for Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, 35392 Giessen, Germany
| | - Ahmed Mostafa
- Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza 12622, Egypt
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Navarro-Lopez R, Xu W, Gomez-Romero N, Velazquez-Salinas L, Berhane Y. Phylogenetic Inference of the 2022 Highly Pathogenic H7N3 Avian Influenza Outbreak in Northern Mexico. Pathogens 2022; 11:1284. [PMID: 36365034 PMCID: PMC9692817 DOI: 10.3390/pathogens11111284] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/20/2022] [Accepted: 10/25/2022] [Indexed: 02/06/2024] Open
Abstract
The Mexican lineage H7N3 highly pathogenic avian influenza virus (HPAIV) has persisted in Mexican poultry since its first isolation in 2012. To date, the detection of this virus has gradually expanded from the initial one state to 18 states in Mexico. Despite the HPAIV H7N3 outbreak occurring yearly, the transmission pathways have never been studied, disallowing the establishment of effective control measures. We used a phylogenetic approach to unravel the transmission pathways of 2022 H7N3 HPAIVs in the new outbreak areas in Northern Mexico. We present genetic data of H7N3 viruses produced from 18 poultry farms infected in the spring of 2022. Our results indicate that the virus responsible for the current outbreak in Northern Mexico evolved from the Mexican lineage H7N3 HPAIV discovered in 2012. In the current outbreak, we identified five clusters of infection with four noticeably different genetic backgrounds. It is a cluster IV-like virus that was transmitted into one northern state causing an outbreak, then spreading to another neighboring northern state, possibly via a human-mediated mechanical transmission mechanism. The long-distance transmission event highlights the necessity for the more rigorous enforcement of biosafety measures in outbreaks. Additionally, we examined the evolutionary processes shaping the viral genetic and antigenic diversities. It is imperative to enhance active surveillance to include birds, the environment, and humans to detect HPAI in domestic poultry at an earlier point and eliminate it.
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Affiliation(s)
- Roberto Navarro-Lopez
- United States-Mexico Commission for the Prevention of Foot-and-Mouth Disease and Other Exotic Disease Animals, Mexico City 64590, Mexico
| | - Wanhong Xu
- National Centre for Foreign Animal Disease, Winnipeg, MB R3E 3M4, Canada
| | - Ninnet Gomez-Romero
- United States-Mexico Commission for the Prevention of Foot-and-Mouth Disease and Other Exotic Disease Animals, Mexico City 64590, Mexico
| | - Lauro Velazquez-Salinas
- Plum Island Animal Disease Center, Agriculture Research Service, USDA, Orient, NY 11944, USA
| | - Yohannes Berhane
- National Centre for Foreign Animal Disease, Winnipeg, MB R3E 3M4, Canada
- Department of Animal Science, University of Manitoba, Winnipeg, MB R3T 2S2, Canada
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Yeo SJ, Hoang VT, Duong TB, Nguyen NM, Tuong HT, Azam M, Sung HW, Park H. Emergence of a Novel Reassortant H5N3 Avian Influenza Virus in Korean Mallard Ducks in 2018. Intervirology 2021; 65:1-16. [PMID: 34438407 DOI: 10.1159/000517057] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 04/29/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION The avian influenza (AI) virus causes a highly contagious disease which is common in wild and domestic birds and sporadic in humans. Mutations and genetic reassortments among the 8 negative-sense RNA segments of the viral genome alter its pathogenic potential, demanding well-targeted, active surveillance for infection control. METHODS Wild duck fecal samples were collected during the 2018 bird health annual surveillance in South Korea for tracking variations of the AI virus. One low-pathogenic avian influenza H5N3 reassortment virus (A/mallard duck/South Korea/KNU18-91/2018 [H5N3]) was isolated and genomically characterized by phylogenetic and molecular analyses in this study. RESULTS It was devoid of polybasic amino acids at the hemagglutinin (HA) cleavage site and exhibited a stalk region without deletion in the neuraminidase (NA) gene and NA inhibitor resistance-linked E/D627K/N and D701N marker mutations in the PB2 gene, suggesting its low-pathogenic AI. It showed a potential of a reassortment where only HA originated from the H5N3 poultry virus of China and other genes were derived from Mongolia. In phylogenetic analysis, HA was different from that of the isolate of H5N3 in Korea, 2015. In addition, this novel virus showed adaptation in Madin-Darby canine kidney cells, with 8.05 ± 0.14 log10 50% tissue culture infectious dose (TCID50) /mL at 36 h postinfection. However, it could not replicate in mice well, showing positive growth at 3 days postinfection (dpi) (2.1 ± 0.13 log10 TCID50/mL) but not at 6 dpi. CONCLUSIONS The HA antigenic relationship of A/mallard duck/South Korea/KNU18-91/2018 (H5N3) showed differences toward one of the old low-pathogenic H5N3 viruses in Korea. These results indicated that a novel reassortment low-pathogenic avian influenza H5N3 subtype virus emerged in South Korea in 2018 via novel multiple reassortments with Eurasian viruses, rather than one of old Korean H5N3 strains.
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Affiliation(s)
- Seon-Ju Yeo
- Department of Tropical Medicine and Parasitology, Seoul National University College of Medicine, Seoul, Republic of Korea,
| | - Vui Thi Hoang
- Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, Republic of Korea
| | - Tuan Bao Duong
- Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, Republic of Korea
| | - Ngoc Minh Nguyen
- Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, Republic of Korea
| | - Hien Thi Tuong
- Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, Republic of Korea
| | - Mudsser Azam
- Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, Republic of Korea
| | - Haan Woo Sung
- College of Veterinary Medicine, Kangwon National University, Chuncheon, Republic of Korea
| | - Hyun Park
- Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, Republic of Korea
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Trinh TTT, Duong BT, Nguyen ATV, Tuong HT, Hoang VT, Than DD, Nam S, Sung HW, Yun KJ, Yeo SJ, Park H. Emergence of Novel Reassortant H1N1 Avian Influenza Viruses in Korean Wild Ducks in 2018 and 2019. Viruses 2020; 13:v13010030. [PMID: 33375376 PMCID: PMC7823676 DOI: 10.3390/v13010030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 12/19/2020] [Accepted: 12/24/2020] [Indexed: 02/08/2023] Open
Abstract
Influenza A virus subtype H1N1 has caused global pandemics like the “Spanish flu” in 1918 and the 2009 H1N1 pandemic several times. H1N1 remains in circulation and survives in multiple animal sources, including wild birds. Surveillance during the winter of 2018–2019 in Korea revealed two H1N1 isolates in samples collected from wild bird feces: KNU18-64 (A/Greater white-fronted goose/South Korea/KNU18-64/2018(H1N1)) and WKU19-4 (A/wild bird/South Korea/WKU19-4/2019(H1N1)). Phylogenetic analysis indicated that M gene of KNU18-64(H1N1) isolate resembles that of the Alaskan avian influenza virus, whereas WKU19-4(H1N1) appears to be closer to the Mongolian virus. Molecular characterization revealed that they harbor the amino acid sequence PSIQRS↓GLF and are low-pathogenicity influenza viruses. In particular, the two isolates harbored three different mutation sites, indicating that they have different virulence characteristics. The mutations in the PB1-F2 and PA protein of WKU19-4(H1N1) indicate increasing polymerase activity. These results corroborate the kinetic growth data for WKU19-4 in MDCK cells: a dramatic increase in the viral titer after 12 h post-inoculation compared with that in the control group H1N1 (CA/04/09(pdm09)). The KNU18-64(H1N1) isolate carries mutations indicating an increase in mammal adaptation; this characterization was confirmed by the animal study in mice. The KNU18-64(H1N1) group showed the presence of viruses in the lungs at days 3 and 6 post-infection, with titers of 2.71 ± 0.16 and 3.71 ± 0.25 log10(TCID50/mL), respectively, whereas the virus was only detected in the WKU19-4(H1N1) group at day 6 post-infection, with a lower titer of 2.75 ± 0.51 log10(TCID50/mL). The present study supports the theory that there is a relationship between Korea and America with regard to reassortment to produce novel viral strains. Therefore, there is a need for increased surveillance of influenza virus circulation in free-flying and wild land-based birds in Korea, particularly with regard to Alaskan and Asian strains.
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Affiliation(s)
- Thuy-Tien Thi Trinh
- Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan 570-749, Korea; (T.-T.T.T.); (B.T.D.); (A.T.V.N.); (H.T.T.); (V.T.H.); (D.D.T.)
| | - Bao Tuan Duong
- Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan 570-749, Korea; (T.-T.T.T.); (B.T.D.); (A.T.V.N.); (H.T.T.); (V.T.H.); (D.D.T.)
| | - Anh Thi Viet Nguyen
- Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan 570-749, Korea; (T.-T.T.T.); (B.T.D.); (A.T.V.N.); (H.T.T.); (V.T.H.); (D.D.T.)
| | - Hien Thi Tuong
- Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan 570-749, Korea; (T.-T.T.T.); (B.T.D.); (A.T.V.N.); (H.T.T.); (V.T.H.); (D.D.T.)
| | - Vui Thi Hoang
- Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan 570-749, Korea; (T.-T.T.T.); (B.T.D.); (A.T.V.N.); (H.T.T.); (V.T.H.); (D.D.T.)
| | - Duong Duc Than
- Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan 570-749, Korea; (T.-T.T.T.); (B.T.D.); (A.T.V.N.); (H.T.T.); (V.T.H.); (D.D.T.)
| | - SunJeong Nam
- Division of EcoScience, Ewha University, Seoul 03760, Korea;
| | - Haan Woo Sung
- College of Veterinary Medicine, Kangwon National University, Chuncheon 200-701, Korea;
| | - Ki-Jung Yun
- Department of Pathology, School of Medicine, Wonkwang University, Iksan 570-749, Korea;
| | - Seon-Ju Yeo
- Department of Tropical Medicine and Parasitology, College of Medicine, Seoul National University, Seoul 03080, Korea
- Correspondence: (S.-J.Y.); (H.P.)
| | - Hyun Park
- Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan 570-749, Korea; (T.-T.T.T.); (B.T.D.); (A.T.V.N.); (H.T.T.); (V.T.H.); (D.D.T.)
- Correspondence: (S.-J.Y.); (H.P.)
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9
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Mostafa A, Blaurock C, Scheibner D, Müller C, Blohm U, Schäfer A, Gischke M, Salaheldin AH, Nooh HZ, Ali MA, Breithaupt A, Mettenleiter TC, Pleschka S, Abdelwhab EM. Genetic incompatibilities and reduced transmission in chickens may limit the evolution of reassortants between H9N2 and panzootic H5N8 clade 2.3.4.4 avian influenza virus showing high virulence for mammals. Virus Evol 2020; 6:veaa077. [PMID: 33343923 PMCID: PMC7733613 DOI: 10.1093/ve/veaa077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The unprecedented spread of H5N8- and H9N2-subtype avian influenza virus (AIV) in birds across Asia, Europe, Africa, and North America poses a serious public health threat with a permanent risk of reassortment and the possible emergence of novel virus variants with high virulence in mammals. To gain information on this risk, we studied the potential for reassortment between two contemporary H9N2 and H5N8 viruses. While the replacement of the PB2, PA, and NS genes of highly pathogenic H5N8 by homologous segments from H9N2 produced infectious H5N8 progeny, PB1 and NP of H9N2 were not able to replace the respective segments from H5N8 due to residues outside the packaging region. Furthermore, exchange of the PB2, PA, and NS segments of H5N8 by those of H9N2 increased replication, polymerase activity and interferon antagonism of the H5N8 reassortants in human cells. Notably, H5N8 reassortants carrying the H9N2-subtype PB2 segment and to lesser extent the PA or NS segments showed remarkably increased virulence in mice as indicated by rapid onset of mortality, reduced mean time to death and increased body weight loss. Simultaneously, we observed that in chickens the H5N8 reassortants, particularly with the H9N2 NS segment, demonstrated significantly reduced transmission to co-housed chickens. Together, while the limited capacity for reassortment between co-circulating H9N2 and H5N8 viruses and the reduced bird-to-bird transmission of possible H5N8 reassortants in chickens may limit the evolution of such reassortant viruses, they show a higher replication potential in human cells and increased virulence in mammals.
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Affiliation(s)
| | | | | | - Christin Müller
- Institute of Medical Virology, Justus Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany
| | - Ulrike Blohm
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany
| | - Alexander Schäfer
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany
| | | | | | - Hanaa Z Nooh
- Department of Anatomy and Histology, College of Medicine, Jouf University, Sakaka 72442, Aljouf Province, Saudi Arabia
| | - Mohamed A Ali
- Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), Dokki, 12622, Giza, Egypt
| | - Angele Breithaupt
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany
| | | | - Stephan Pleschka
- Institute of Medical Virology, Justus Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany
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10
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Mostafa A, Mahmoud SH, Shehata M, Müller C, Kandeil A, El-Shesheny R, Nooh HZ, Kayali G, Ali MA, Pleschka S. PA from a Recent H9N2 (G1-Like) Avian Influenza a Virus (AIV) Strain Carrying Lysine 367 Confers Altered Replication Efficiency and Pathogenicity to Contemporaneous H5N1 in Mammalian Systems. Viruses 2020; 12:v12091046. [PMID: 32962203 PMCID: PMC7551781 DOI: 10.3390/v12091046] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/15/2020] [Accepted: 09/18/2020] [Indexed: 12/03/2022] Open
Abstract
Egypt is a hotspot for H5- and H9-subtype avian influenza A virus (AIV) infections and co-infections in poultry by both subtypes have been frequently reported. However, natural genetic reassortment of these subtypes has not been reported yet. Here, we evaluated the genetic compatibility and replication efficiency of reassortants between recent isolates of an Egyptian H5N1 and a H9N2 AIV (H5N1EGY and H9N2EGY). All internal viral proteins-encoding segments of the contemporaneous G1-like H9N2EGY, expressed individually and in combination in the genetic background of H5N1EGY, were genetically compatible with the other H5N1EGY segments. At 37 °C the replication efficiencies of H5N1EGY reassortants expressing the H9N2EGY polymerase subunits PB2 and PA (H5N1PB2-H9N2EGY, H5N1PA-H9N2EGY) were higher than the wild-type H5N1EGY in Madin-Darby canine kidney (MDCK-II) cells. This could not be correlated to viral polymerase activity as this was found to be improved for H5N1PB2-H9N2EGY, but reduced for H5N1PA-H9N2EGY. At 33 °C and 39 °C, H5N1PB2-H9N2EGY and H5N1PA-H9N2EGY replicated to higher levels than the wild-type H5N1EGY in human Calu-3 and A549 cell lines. Nevertheless, in BALB/c mice both reassortants caused reduced mortality compared to the wild-type H5N1EGY. Genetic analysis of the polymerase-encoding segments revealed that the PAH9N2EGY and PB2H9N2EGY encode for a distinct uncharacterized mammalian-like variation (367K) and a well-known mammalian signature (591K), respectively. Introducing the single substitution 367K into the PA of H5N1EGY enabled the mutant virus H5N1PA-R367K to replicate more efficiently at 37 °C in primary human bronchial epithelial (NHBE) cells and also in A549 and Calu-3 cells at 33 °C and 39 °C. Furthermore, H5N1PA-R367K caused higher mortality in BALB/c mice. These findings demonstrate that H5N1 (Clade 2.2.1.2) reassortants carrying internal proteins-encoding segments of G1-like H9N2 viruses can emerge and may gain improved replication fitness. Thereby such H5N1/H9N2 reassortants could augment the zoonotic potential of H5N1 viruses, especially by acquiring unique mammalian-like aa signatures.
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Affiliation(s)
- Ahmed Mostafa
- Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), 12622 Giza, Egypt; (S.H.M.); (M.S.); (A.K.); (R.E.-S.)
- Institute of Medical Virology, Justus Liebig University Giessen, Schubertstrasse 81, 35390 Giessen, Germany;
- Correspondence: (A.M); (M.A.A.); (S.P.)
| | - Sara H. Mahmoud
- Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), 12622 Giza, Egypt; (S.H.M.); (M.S.); (A.K.); (R.E.-S.)
| | - Mahmoud Shehata
- Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), 12622 Giza, Egypt; (S.H.M.); (M.S.); (A.K.); (R.E.-S.)
| | - Christin Müller
- Institute of Medical Virology, Justus Liebig University Giessen, Schubertstrasse 81, 35390 Giessen, Germany;
| | - Ahmed Kandeil
- Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), 12622 Giza, Egypt; (S.H.M.); (M.S.); (A.K.); (R.E.-S.)
| | - Rabeh El-Shesheny
- Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), 12622 Giza, Egypt; (S.H.M.); (M.S.); (A.K.); (R.E.-S.)
- St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Hanaa Z. Nooh
- Anatomy and Embryology Department, Faculty of Medicine, Jouf University, Sakaka 2014, Saudi Arabia;
| | - Ghazi Kayali
- Department of Epidemiology, Human Genetics, and Environmental Sciences, University of Texas, Houston, TX 77030, USA;
- Human Link, Baabda 1109, Lebanon
| | - Mohamed A. Ali
- Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), 12622 Giza, Egypt; (S.H.M.); (M.S.); (A.K.); (R.E.-S.)
- Correspondence: (A.M); (M.A.A.); (S.P.)
| | - Stephan Pleschka
- Institute of Medical Virology, Justus Liebig University Giessen, Schubertstrasse 81, 35390 Giessen, Germany;
- Correspondence: (A.M); (M.A.A.); (S.P.)
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11
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Suttie A, Deng YM, Greenhill AR, Dussart P, Horwood PF, Karlsson EA. Inventory of molecular markers affecting biological characteristics of avian influenza A viruses. Virus Genes 2019; 55:739-768. [PMID: 31428925 PMCID: PMC6831541 DOI: 10.1007/s11262-019-01700-z] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 08/09/2019] [Indexed: 12/20/2022]
Abstract
Avian influenza viruses (AIVs) circulate globally, spilling over into domestic poultry and causing zoonotic infections in humans. Fortunately, AIVs are not yet capable of causing sustained human-to-human infection; however, AIVs are still a high risk as future pandemic strains, especially if they acquire further mutations that facilitate human infection and/or increase pathogenesis. Molecular characterization of sequencing data for known genetic markers associated with AIV adaptation, transmission, and antiviral resistance allows for fast, efficient assessment of AIV risk. Here we summarize and update the current knowledge on experimentally verified molecular markers involved in AIV pathogenicity, receptor binding, replicative capacity, and transmission in both poultry and mammals with a broad focus to include data available on other AIV subtypes outside of A/H5N1 and A/H7N9.
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Affiliation(s)
- Annika Suttie
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Blvd, PO Box #983, Phnom Penh, Cambodia
- School of Health and Life Sciences, Federation University, Churchill, Australia
- World Health Organization Collaborating Centre for Reference and Research on Influenza, Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Yi-Mo Deng
- World Health Organization Collaborating Centre for Reference and Research on Influenza, Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Andrew R Greenhill
- School of Health and Life Sciences, Federation University, Churchill, Australia
| | - Philippe Dussart
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Blvd, PO Box #983, Phnom Penh, Cambodia
| | - Paul F Horwood
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Erik A Karlsson
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Blvd, PO Box #983, Phnom Penh, Cambodia.
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12
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Species-Specific Host-Virus Interactions: Implications for Viral Host Range and Virulence. Trends Microbiol 2019; 28:46-56. [PMID: 31597598 DOI: 10.1016/j.tim.2019.08.007] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 08/11/2019] [Accepted: 08/19/2019] [Indexed: 01/09/2023]
Abstract
A growing number of studies indicate that host species-specific and virus strain-specific interactions of viral molecules with the host innate immune system play a pivotal role in determining virus host range and virulence. Because interacting proteins are likely constrained in their evolution, mutations that are selected to improve virus replication in one species may, by chance, alter the ability of a viral antagonist to inhibit immune responses in hosts the virus has not yet encountered. Based on recent findings of host-species interactions of poxvirus, herpesvirus, and influenza virus proteins, we propose a model for viral fitness and host range which considers the full interactome between a specific host species and a virus, resulting from the combination of all interactions, positive and negative, that influence whether a virus can productively infect a cell and cause disease in different hosts.
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13
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Mostafa A, Abdelwhab EM, Mettenleiter TC, Pleschka S. Zoonotic Potential of Influenza A Viruses: A Comprehensive Overview. Viruses 2018; 10:v10090497. [PMID: 30217093 PMCID: PMC6165440 DOI: 10.3390/v10090497] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/24/2018] [Accepted: 09/13/2018] [Indexed: 02/06/2023] Open
Abstract
Influenza A viruses (IAVs) possess a great zoonotic potential as they are able to infect different avian and mammalian animal hosts, from which they can be transmitted to humans. This is based on the ability of IAV to gradually change their genome by mutation or even reassemble their genome segments during co-infection of the host cell with different IAV strains, resulting in a high genetic diversity. Variants of circulating or newly emerging IAVs continue to trigger global health threats annually for both humans and animals. Here, we provide an introduction on IAVs, highlighting the mechanisms of viral evolution, the host spectrum, and the animal/human interface. Pathogenicity determinants of IAVs in mammals, with special emphasis on newly emerging IAVs with pandemic potential, are discussed. Finally, an overview is provided on various approaches for the prevention of human IAV infections.
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Affiliation(s)
- Ahmed Mostafa
- Institute of Medical Virology, Justus Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany.
- Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), Giza 12622, Egypt.
| | - Elsayed M Abdelwhab
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | - Thomas C Mettenleiter
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | - Stephan Pleschka
- Institute of Medical Virology, Justus Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany.
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14
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Petersen H, Mostafa A, Tantawy MA, Iqbal AA, Hoffmann D, Tallam A, Selvakumar B, Pessler F, Beer M, Rautenschlein S, Pleschka S. NS Segment of a 1918 Influenza A Virus-Descendent Enhances Replication of H1N1pdm09 and Virus-Induced Cellular Immune Response in Mammalian and Avian Systems. Front Microbiol 2018; 9:526. [PMID: 29623073 PMCID: PMC5874506 DOI: 10.3389/fmicb.2018.00526] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/08/2018] [Indexed: 12/14/2022] Open
Abstract
The 2009 pandemic influenza A virus (IAV) H1N1 strain (H1N1pdm09) has widely spread and is circulating in humans and swine together with other human and avian IAVs. This fact raises the concern that reassortment between H1N1pdm09 and co-circulating viruses might lead to an increase of H1N1pdm09 pathogenicity in different susceptible host species. Herein, we explored the potential of different NS segments to enhance the replication dynamics, pathogenicity and host range of H1N1pdm09 strain A/Giessen/06/09 (Gi-wt). The NS segments were derived from (i) human H1N1- and H3N2 IAVs, (ii) highly pathogenic- (H5- or H7-subtypes) or (iii) low pathogenic avian influenza viruses (H7- or H9-subtypes). A significant increase of growth kinetics in A549 (human lung epithelia) and NPTr (porcine tracheal epithelia) cells was only noticed in vitro for the reassortant Gi-NS-PR8 carrying the NS segment of the 1918-descendent A/Puerto Rico/8/34 (PR8-wt, H1N1), whereas all other reassortants showed either reduced or comparable replication efficiencies. Analysis using ex vivo tracheal organ cultures of turkeys (TOC-Tu), a species susceptible to IAV H1N1 infection, demonstrated increased replication of Gi-NS-PR8 compared to Gi-wt. Also, Gi-NS-PR8 induced a markedly higher expression of immunoregulatory and pro-inflammatory cytokines, chemokines and interferon-stimulated genes in A549 cells, THP-1-derived macrophages (dHTP) and TOC-Tu. In vivo, Gi-NS-PR8 induced an earlier onset of mortality than Gi-wt in mice, whereas, 6-week-old chickens were found to be resistant to both viruses. These data suggest that the specific characteristics of the PR8 NS segments can impact on replication, virus induced cellular immune responses and pathogenicity of the H1N1pdm09 in different avian and mammalian host species.
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Affiliation(s)
- Henning Petersen
- Clinic for Poultry, University of Veterinary Medicine Hannover, Hanover, Germany
| | - Ahmed Mostafa
- Institute of Medical Virology, Justus Liebig University Giessen, Giessen, Germany.,Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), Cairo, Egypt
| | - Mohamed A Tantawy
- Institute for Experimental Infection Research, TWINCORE Centre for Experimental and Clinical Infection Research, Hanover, Germany.,Department of Hormones, Medical Research Division, National Research Centre, Cairo, Egypt
| | - Azeem A Iqbal
- Institute for Experimental Infection Research, TWINCORE Centre for Experimental and Clinical Infection Research, Hanover, Germany.,Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Donata Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Aravind Tallam
- Institute for Experimental Infection Research, TWINCORE Centre for Experimental and Clinical Infection Research, Hanover, Germany
| | - Balachandar Selvakumar
- Max-Planck Laboratory for Heart and Lung Research, Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET-Partner Institute of the Max Planck Society, Buenos Aires, Argentina
| | - Frank Pessler
- Institute for Experimental Infection Research, TWINCORE Centre for Experimental and Clinical Infection Research, Hanover, Germany.,Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Silke Rautenschlein
- Clinic for Poultry, University of Veterinary Medicine Hannover, Hanover, Germany
| | - Stephan Pleschka
- Institute of Medical Virology, Justus Liebig University Giessen, Giessen, Germany
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15
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Shah Mahmud R, Mostafa A, Müller C, Kanrai P, Ulyanova V, Sokurenko Y, Dzieciolowski J, Kuznetsova I, Ilinskaya O, Pleschka S. Bacterial ribonuclease binase exerts an intra-cellular anti-viral mode of action targeting viral RNAs in influenza a virus-infected MDCK-II cells. Virol J 2018; 15:5. [PMID: 29304825 PMCID: PMC5756404 DOI: 10.1186/s12985-017-0915-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/19/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Influenza is a severe contagious disease especially in children, elderly and immunocompromised patients. Beside vaccination, the discovery of new anti-viral agents represents an important strategy to encounter seasonal and pandemic influenza A virus (IAV) strains. The bacterial extra-cellular ribonuclease binase is a well-studied RNase from Bacillus pumilus. Treatment with binase was shown to improve survival of laboratory animals infected with different RNA viruses. Although binase reduced IAV titer in vitro and in vivo, the mode of action (MOA) of binase against IAV at the molecular level has yet not been studied in depth and remains elusive. METHODS To analyze whether binase impairs virus replication by direct interaction with the viral particle we applied a hemagglutination inhibition assay and monitored the integrity of the viral RNA within the virus particle by RT-PCR. Furthermore, we used Western blot and confocal microscopy analysis to study whether binase can internalize into MDCK-II cells. By primer extension we examined the effect of binase on the integrity of viral RNAs within the cells and using a mini-genome system we explored the effect of binase on the viral expression. RESULTS We show that (i) binase does not to attack IAV particle-protected viral RNA, (ii) internalized binase could be detected within the cytosol of MDCK-II cells and that (iii) binase impairs IAV replication by specifically degrading viral RNA species within the infected MDCK-II cells without obvious effect on cellular mRNAs. CONCLUSION Our data provide novel evidence suggesting that binase is a potential anti-viral agent with specific intra-cellular MOA.
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Affiliation(s)
- Raihan Shah Mahmud
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlyovskaya Street 18, 420008, Kazan, Russia
| | - Ahmed Mostafa
- Institute of Medical Virology, Justus Liebig University, Schubertstrasse 81, 35392, Giessen, Germany
- Center of Scientific Excellence for Influenza Viruses, National Research Center (NRC), El-Buhouth Street 87, 12311 Dokki, Cairo, Egypt
| | - Christin Müller
- Institute of Medical Virology, Justus Liebig University, Schubertstrasse 81, 35392, Giessen, Germany
| | - Pumaree Kanrai
- Institute of Medical Virology, Justus Liebig University, Schubertstrasse 81, 35392, Giessen, Germany
- Present address: Department I - Cardiac Development and Remodelling, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, 61231, Bad Nauheim, Germany
| | - Vera Ulyanova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlyovskaya Street 18, 420008, Kazan, Russia
| | - Yulia Sokurenko
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlyovskaya Street 18, 420008, Kazan, Russia
| | - Julia Dzieciolowski
- Institute of Medical Virology, Justus Liebig University, Schubertstrasse 81, 35392, Giessen, Germany
- Present address: Department of Biochemistry and Molecular Biology, Institute of Nutritional Science, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany
| | - Irina Kuznetsova
- Institute of Medical Virology, Justus Liebig University, Schubertstrasse 81, 35392, Giessen, Germany
| | - Olga Ilinskaya
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlyovskaya Street 18, 420008, Kazan, Russia
| | - Stephan Pleschka
- Institute of Medical Virology, Justus Liebig University, Schubertstrasse 81, 35392, Giessen, Germany.
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Influenza A Virus Virulence Depends on Two Amino Acids in the N-Terminal Domain of Its NS1 Protein To Facilitate Inhibition of the RNA-Dependent Protein Kinase PKR. J Virol 2017; 91:JVI.00198-17. [PMID: 28250123 DOI: 10.1128/jvi.00198-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 02/20/2017] [Indexed: 12/22/2022] Open
Abstract
The RNA-dependent protein kinase (PKR) has broad antiviral activity inducing translational shutdown of viral and cellular genes and is therefore targeted by various viral proteins to facilitate pathogen propagation. The pleiotropic NS1 protein of influenza A virus acts as silencer of PKR activation and ensures high-level viral replication and virulence. However, the exact manner of this inhibition remains controversial. To elucidate the structural requirements within the NS1 protein for PKR inhibition, we generated a set of mutant viruses, identifying highly conserved arginine residues 35 and 46 within the NS1 N terminus as being most critical not only for binding to and blocking activation of PKR but also for efficient virus propagation. Biochemical and Förster resonance energy transfer (FRET)-based interaction studies showed that mutation of R35 or R46 allowed formation of NS1 dimers but eliminated any detectable binding to PKR as well as to double-stranded RNA (dsRNA). Using in vitro and in vivo approaches to phenotypic restoration, we demonstrated the essential role of the NS1 N terminus for blocking PKR. The strong attenuation conferred by NS1 mutation R35A or R46A was substantially alleviated by stable knockdown of PKR in human cells. Intriguingly, both NS1 mutant viruses did not trigger any signs of disease in PKR+/+ mice, but replicated to high titers in lungs of PKR-/- mice and caused lethal infections. These data not only establish the NS1 N terminus as highly critical for neutralization of PKR's antiviral activity but also identify this blockade as an indispensable contribution of NS1 to the viral life cycle.IMPORTANCE Influenza A virus inhibits activation of the RNA-dependent protein kinase (PKR) by means of its nonstructural NS1 protein, but the underlying mode of inhibition is debated. Using mutational analysis, we identified arginine residues 35 and 46 within the N-terminal NS1 domain as highly critical for binding to and functional silencing of PKR. In addition, our data show that this is a main activity of amino acids 35 and 46, as the strong attenuation of corresponding mutant viruses in human cells was rescued to a large extent by lowering of PKR expression levels. Significantly, this corresponded with restoration of viral virulence for NS1 R35A and R46A mutant viruses in PKR-/- mice. Therefore, our data establish a model in which the NS1 N-terminal domain engages in a binding interaction to inhibit activation of PKR and ensure efficient viral propagation and virulence.
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