scholarly journals Knockout of IRF7 Highlights its Modulator Function of Host Response Against Avian Influenza Virus and the Involvement of MAPK and TOR Signaling Pathways in Chicken

Genes ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 385
Author(s):  
Tae Hyun Kim ◽  
Colin Kern ◽  
Huaijun Zhou

Interferon regulatory factor 7 (IRF7) is known as the master transcription factor of the type I interferon response in mammalian species along with IRF3. Yet birds only have IRF7, while they are missing IRF3, with a smaller repertoire of immune-related genes, which leads to a distinctive immune response in chickens compared to in mammals. In order to understand the functional role of IRF7 in the regulation of the antiviral response against avian influenza virus in chickens, we generated IRF7-/- chicken embryonic fibroblast (DF-1) cell lines and respective controls (IRF7wt) by utilizing the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) system. IRF7 knockout resulted in increased viral titers of low pathogenic avian influenza viruses. Further RNA-sequencing performed on H6N2-infected IRF7-/- and IRF7wt cell lines revealed that the deletion of IRF7 resulted in the significant down-regulation of antiviral effectors and the differential expression of genes in the MAPK (mitogen-activated protein kinase) and mTOR (mechanistic target of rapamycin) signaling pathways. Dynamic gene expression profiling of the host response between the wildtype and IRF7 knockout revealed potential signaling pathways involving AP1 (activator protein 1), NF-κB (nuclear factor kappa B) and inflammatory cytokines that may complement chicken IRF7. Our findings in this study provide novel insights that have not been reported previously, and lay a solid foundation for enhancing our understanding of the host antiviral response against the avian influenza virus in chickens.

2021 ◽  
Vol 1 ◽  
Author(s):  
Fengming Zhao ◽  
Yuqing Wang ◽  
Liping Chen ◽  
Xinxing Zhang ◽  
Mariette Ducatez ◽  
...  

Subtype H9N2 avian influenza viruses (AIV), now the predominant avian influenza virus subtype in poultry in China, cause sporadic human infections manifesting as mild influenza-like illness. We isolated an H9N2 AIV from a critical case of respiratory illness in a 9-year-old with no underlying conditions. As this virus was associated with critical illness, we conducted a risk assessment to determine its mammalian pathogenicity. Clinical and laboratory data were collected from hospital records. A/Suzhou/GIRD01/2019 (H9N2) (GIRD01) was isolated from a throat swab and used in risk-assessment studies in comparison to prototypical and contemporary H9N2 AIVs and contemporary seasonal subtype H1N1 and H3N2 influenza viruses. The patient presented with fever, vomiting but rapidly declined to progressive wheezing followed by dyspnea. The patient was admitted to the intensive care unit and placed on mechanical ventilation. A diagnosis of pneumonia and type I respiratory failure was made. Viral RNA was detected in the bronchiolavelolar lavage and anal swab specimens, suggesting lower lung and extrapulmonary involvement. Respiratory syncytial virus was also detected by immunofluorescence in bronchiolavelolar lavage. Following an aggressive regimen of antiviral and antibacterial therapy, the patient recovered and was discharged from hospital after 13 days. GIRD01 was closely related to poultry-origin H9N2 AIVs in the area and contained several known markers of mammalian pathogenicity. GIRD01 also showed a strong affinity for mammalian-type over avian-type sialic acids. GIRD01 replicated more efficiently compared to older H9N2 viruses and contemporary seasonal viruses in vitro and produced asymptomatic infections in mice. In summary, GIRD01 was well-adapted to replication in in vitro and in vivo mammalian models but was not more pathogenic compared to similar contemporary strains of H9N2 AIVs. Therefore, these viruses may pose a risk of causing severe respiratory disease in humans.


2014 ◽  
Vol 191 ◽  
pp. 184-191 ◽  
Author(s):  
Qiang Shao ◽  
Wenpin Xu ◽  
Li Yan ◽  
Jinhua Liu ◽  
Lei Rui ◽  
...  

2020 ◽  
Vol 94 (12) ◽  
Author(s):  
Thomas P. Peacock ◽  
Olivia C. Swann ◽  
Hamish A. Salvesen ◽  
Ecco Staller ◽  
P. Brian Leung ◽  
...  

ABSTRACT Avian influenza viruses occasionally infect and adapt to mammals, including humans. Swine are often described as “mixing vessels,” being susceptible to both avian- and human-origin viruses, which allows the emergence of novel reassortants, such as the precursor to the 2009 H1N1 pandemic. ANP32 proteins are host factors that act as influenza virus polymerase cofactors. In this study, we describe how swine ANP32A, uniquely among the mammalian ANP32 proteins tested, supports the activity of avian-origin influenza virus polymerases and avian influenza virus replication. We further show that after the swine-origin influenza virus emerged in humans and caused the 2009 pandemic, it evolved polymerase gene mutations that enabled it to more efficiently use human ANP32 proteins. We map the enhanced proviral activity of swine ANP32A to a pair of amino acids, 106 and 156, in the leucine-rich repeat and central domains and show these mutations enhance binding to influenza virus trimeric polymerase. These findings help elucidate the molecular basis for the mixing vessel trait of swine and further our understanding of the evolution and ecology of viruses in this host. IMPORTANCE Avian influenza viruses can jump from wild birds and poultry into mammalian species such as humans or swine, but they only continue to transmit if they accumulate mammalian adapting mutations. Pigs appear uniquely susceptible to both avian and human strains of influenza and are often described as virus “mixing vessels.” In this study, we describe how a host factor responsible for regulating virus replication, ANP32A, is different between swine and humans. Swine ANP32A allows a greater range of influenza viruses, specifically those from birds, to replicate. It does this by binding the virus polymerase more tightly than the human version of the protein. This work helps to explain the unique properties of swine as mixing vessels.


2010 ◽  
Vol 17 (3) ◽  
pp. 454-463 ◽  
Author(s):  
Hamid R. Hghihghi ◽  
Leah R. Read ◽  
Hakimeh Mohammadi ◽  
Yanlong Pei ◽  
Claudia Ursprung ◽  
...  

ABSTRACT There currently are commercial fowlpox virus (FPV)-vectored vaccines for use in chickens, including TROVAC-AIV H5, which expresses the hemagglutinin (HA) antigen of an avian influenza virus and can confer immunity against avian influenza in chickens. Despite the use of recombinant FPV (rFPV) for vaccine delivery, very little is known about the immune responses generated by these viruses in chickens. The present study was designed to investigate host responses to rFPV in vivo and in vitro. In cultured cells infected with TROVAC-AIV H5, there was an early increase in the expression of type I interferons (IFN), Toll-like receptors 3 and 7 (TLR3 and TLR7, respectively), TRIF, and MyD88, which was followed by a decrease in the expression of these genes at later time points. There also was an increase in the expression of interleukin-1β (IL-1β), IL-8, and beta-defensin genes at early time points postinfection. In chickens immunized with TROVAC-AIV H5, there was higher expression of IFN-γ and IL-10 at day 5 postvaccination in spleen of vaccinated birds than in that of control birds. We further investigated the ability of the vaccine to induce immune responses against the HA antigen and discovered that there was a cell-mediated response elicited in vaccinated chickens against this antigen. The findings of this study demonstrate that FPV-vectored vaccines can elicit a repertoire of responses marked by the early expression of TLRs, type I interferons, and proinflammatory cytokines, as well as cytokines associated with adaptive immune responses. This study provides a platform for designing future generations of rFPV-vectored vaccines.


2019 ◽  
Vol 7 ◽  
pp. 251513551882162 ◽  
Author(s):  
Ivette A. Nuñez ◽  
Ted M. Ross

Highly pathogenic avian influenza viruses (HPAIVs), originating from the A/goose/Guangdong/1/1996 H5 subtype, naturally circulate in wild-bird populations, particularly waterfowl, and often spill over to infect domestic poultry. Occasionally, humans are infected with HPAVI H5N1 resulting in high mortality, but no sustained human-to-human transmission. In this review, the replication cycle, pathogenicity, evolution, spread, and transmission of HPAIVs of H5Nx subtypes, along with the host immune responses to Highly Pathogenic Avian Influenza Virus (HPAIV) infection and potential vaccination, are discussed. In addition, the potential mechanisms for Highly Pathogenic Avian Influenza Virus (HPAIV) H5 Reassorted Viruses H5N1, H5N2, H5N6, H5N8 (H5Nx) viruses to transmit, infect, and adapt to the human host are reviewed.


2000 ◽  
Vol 74 (3) ◽  
pp. 1443-1450 ◽  
Author(s):  
Jody K. Dybing ◽  
Stacey Schultz-Cherry ◽  
David E. Swayne ◽  
David L. Suarez ◽  
Michael L. Perdue

ABSTRACT In 1997, an outbreak of virulent H5N1 avian influenza virus occurred in poultry in Hong Kong (HK) and was linked to a direct transmission to humans. The factors associated with transmission of avian influenza virus to mammals are not fully understood, and the potential risk of other highly virulent avian influenza A viruses infecting and causing disease in mammals is not known. In this study, two avian and one human HK-origin H5N1 virus along with four additional highly pathogenic H5 avian influenza viruses were analyzed for their pathogenicity in 6- to 8-week-old BALB/c mice. Both the avian and human HK H5 influenza virus isolates caused severe disease in mice, characterized by induced hypothermia, clinical signs, rapid weight loss, and 75 to 100% mortality by 6 to 8 days postinfection. Three of the non-HK-origin isolates caused no detectable clinical signs. One isolate, A/tk/England/91 (H5N1), induced measurable disease, and all but one of the animals recovered. Infections resulted in mild to severe lesions in both the upper and lower respiratory tracts. Most consistently, the viruses caused necrosis in respiratory epithelium of the nasal cavity, trachea, bronchi, and bronchioles with accompanying inflammation. The most severe and widespread lesions were observed in the lungs of HK avian influenza virus-infected mice, while no lesions or only mild lesions were evident with A/ck/Scotland/59 (H5N1) and A/ck/Queretaro/95 (H5N2). The A/ck/Italy/97 (H5N2) and the A/tk/England/91 (H5N1) viruses exhibited intermediate pathogenicity, producing mild to moderate respiratory tract lesions. In addition, infection by the different isolates could be further distinguished by the mouse immune response. The non-HK-origin isolates all induced production of increased levels of active transforming growth factor β following infection, while the HK-origin isolates did not.


2014 ◽  
Vol 88 (16) ◽  
pp. 9321-9334 ◽  
Author(s):  
S. B. Kasloff ◽  
M. S. Pizzuto ◽  
M. Silic-Benussi ◽  
S. Pavone ◽  
V. Ciminale ◽  
...  

2019 ◽  
Author(s):  
Xiaorong Guo ◽  
Dong Yang ◽  
Ruchun Liu ◽  
Yaman Li ◽  
Qingqing Hu ◽  
...  

Abstract Background: Detecting avian influenza virus has become an important public health strategy for controlling the emerging infectious disease. This study aimed to analyze the efficiency of two surveillance systems in detecting the emerging avian influenza viruses. Methods: A modified influenza surveillance system (ISS) and a new built pneumonia surveillance system (PSS) have been used to monitor the viruses in Changsha City, China. The ISS is based on monitoring outpatients in two sentinel hospitals to detect mild influenza and avian influenza cases, and PSS is based on monitoring inpatients in all 49 hospitals to detect severe and death influenza cases. Results: During the study period, 3551917 outpatients were monitored by the ISS system, among which 126076 were influenza-like illness (ILI) cases, with the ILI% of 3.55%. Totally, 14913 throat swabs were collected by the ISS system, among which 2016 were tested positive of influenza or avian influenza virus. Among the positive results, 621 were H3N2, 135 were seasonal H1N1, 610 were influenza A/H1N1 (pandemic in 2009), 106 were untyped influenza A, 540 were B, 1 was H5N6, 1 was H7N9, and 2 were H9N2 virus. 5491560 inpatient people were monitored by the PSS system, among which 6.61% (362743/5491560) were pneumonia cases. 10.55% (38260/362743) of reported pneumonia was severe or death cases. 3401 throat swab or lower respiratory tract samples were collected, among which 2094 were tested positive of influenza or avian influenza virus. Among the positive results, 78 were H3N2, 17 were seasonal H1N1, 1871 were influenza A/H1N1, 103 were untyped influenza A, 16 were B, 1 was H5N6, and 8 were H7N9 virus. Of 15 avian influenza cases reported from January, 2005 to September, 2016, 26.7% (4/15) were mild cases detected by the ISS system, while 60.0% (9/15) were severe or death cases detected by the PSS system. Two H5N1 severe cases were missed by the ISS system in January, 2009 when the PSS system was not available. Conclusion: The two systems seem to be of high efficiency in detecting the emerging avian influenza viruses but need to be verified in other cities or countries.


2016 ◽  
Author(s):  
Mathieu Fourment ◽  
Aaron E. Darling ◽  
Edward C. Holmes

AbstractWild birds are the major reservoir hosts for influenza A viruses (AIVs) and have been implicated in the emergence of pandemic events in livestock and human populations. Understanding how AIVs spread within and across continents is therefore critical to the development of successful strategies to manage and reduce the impact of influenza outbreaks. In North America many bird species undergo seasonal migratory movements along a North-South axis, thereby fostering opportunities for viruses to spread over long distances. However, the role played by such avian flyways in shaping the genetic structure of AIV populations has proven controversial. To assess the relative contribution of bird migration along flyways to the genetic structure of AIV we performed a large-scale phylogeographic study of viruses sampled in the USA and Canada, involving the analysis of 3805 to 4505 sequences from 36 to 38 geographic localities depending on the gene data set. To assist this we developed a maximum likelihood-based genetic algorithm to explore a wide range of complex spatial models, thereby depicting a more complete picture of the migration network than previous studies. Based on phylogenies estimated from nucleotide data sets, our results show that AIV migration rates within flyways are significantly higher than those between flyways, indicating that the migratory patterns of birds play a key role in pathogen dispersal. These findings provide valuable insights into the evolution, maintenance and transmission of AIVs, in turn allowing the development of improved programs for surveillance and risk assessment.Significance StatementAvian influenza viruses infect a wide variety of wild bird species and represent a potential disease threat to the poultry industry and hence to human and livestock populations. However, the ecological factors that drive the geographic spread and evolution of these viruses are both poorly understood and controversial at the continental scale, particularly the role played by migratory flyways in shaping patterns of virus dispersal. Using a novel phylogeographic analysis of large genomic data sets we show migration flyways act as important transmission barriers to the spread of avian influenza viruses in North America. Hence, these results indicate that the spread of avian influenza virus in wild birds in North America has an element of predictability.


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