Sequence-Specific Imaging of Influenza A mRNA in Living Infected Cells Using Fluorescent FIT–PNA

Author(s):  
Susann Kummer ◽  
Andrea Knoll ◽  
Andreas Herrmann ◽  
Oliver Seitz
Keyword(s):  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Selina Traxler ◽  
Gina Barkowsky ◽  
Radost Saß ◽  
Ann-Christin Klemenz ◽  
Nadja Patenge ◽  
...  

AbstractInfluenza A is a serious pathogen itself, but often leads to dangerous co-infections in combination with bacterial species such as Streptococcus pyogenes. In comparison to classical biochemical methods, analysis of volatile organic compounds (VOCs) in headspace above cultures can enable destruction free monitoring of metabolic processes in vitro. Thus, volatile biomarkers emitted from biological cell cultures and pathogens could serve for monitoring of infection processes in vitro. In this study we analysed VOCs from headspace above (co)-infected human cells by using a customized sampling system. For investigating the influenza A mono-infection and the viral-bacterial co-infection in vitro, we analysed VOCs from Detroit cells inoculated with influenza A virus and S. pyogenes by means of needle-trap micro-extraction (NTME) and gas chromatography mass spectrometry (GC-MS). Besides the determination of microbiological data such as cell count, cytokines, virus load and bacterial load, emissions from cell medium, uninfected cells and bacteria mono-infected cells were analysed. Significant differences in emitted VOC concentrations were identified between non-infected and infected cells. After inoculation with S. pyogenes, bacterial infection was mirrored by increased emissions of acetaldehyde and propanal. N-propyl acetate was linked to viral infection. Non-destructive monitoring of infections by means of VOC analysis may open a new window for infection research and clinical applications. VOC analysis could enable early recognition of pathogen presence and in-depth understanding of their etiopathology.


2007 ◽  
Vol 88 (10) ◽  
pp. 2627-2635 ◽  
Author(s):  
Alexey A. Matskevich ◽  
Karin Moelling

In mammals the interferon (IFN) system is a central innate antiviral defence mechanism, while the involvement of RNA interference (RNAi) in antiviral response against RNA viruses is uncertain. Here, we tested whether RNAi is involved in the antiviral response in mammalian cells. To investigate the role of RNAi in influenza A virus-infected cells in the absence of IFN, we used Vero cells that lack IFN-α and IFN-β genes. Our results demonstrate that knockdown of a key RNAi component, Dicer, led to a modest increase of virus production and accelerated apoptosis of influenza A virus-infected cells. These effects were much weaker in the presence of IFN. The results also show that in both Vero cells and the IFN-producing alveolar epithelial A549 cell line influenza A virus targets Dicer at mRNA and protein levels. Thus, RNAi is involved in antiviral response, and Dicer is important for protection against influenza A virus infection.


2010 ◽  
Vol 84 (24) ◽  
pp. 12832-12840 ◽  
Author(s):  
Yuan He ◽  
Ke Xu ◽  
Bjoern Keiner ◽  
Jianfang Zhou ◽  
Volker Czudai ◽  
...  

ABSTRACT Many viruses interact with the host cell division cycle to favor their own growth. In this study, we examined the ability of influenza A virus to manipulate cell cycle progression. Our results show that influenza A virus A/WSN/33 (H1N1) replication results in G0/G1-phase accumulation of infected cells and that this accumulation is caused by the prevention of cell cycle entry from G0/G1 phase into S phase. Consistent with the G0/G1-phase accumulation, the amount of hyperphosphorylated retinoblastoma protein, a necessary active form for cell cycle progression through late G1 into S phase, decreased after infection with A/WSN/33 (H1N1) virus. In addition, other key molecules in the regulation of the cell cycle, such as p21, cyclin E, and cyclin D1, were also changed and showed a pattern of G0/G1-phase cell cycle arrest. It is interesting that increased viral protein expression and progeny virus production in cells synchronized in the G0/G1 phase were observed compared to those in either unsynchronized cells or cells synchronized in the G2/M phase. G0/G1-phase cell cycle arrest is likely a common strategy, since the effect was also observed in other strains, such as H3N2, H9N2, PR8 H1N1, and pandemic swine H1N1 viruses. These findings, in all, suggest that influenza A virus may provide favorable conditions for viral protein accumulation and virus production by inducing a G0/G1-phase cell cycle arrest in infected cells.


2013 ◽  
Vol 9 (4) ◽  
pp. e1003256 ◽  
Author(s):  
Julien Pothlichet ◽  
Isabelle Meunier ◽  
Beckley K. Davis ◽  
Jenny P-Y. Ting ◽  
Emil Skamene ◽  
...  

2021 ◽  
Vol 21 (3) ◽  
pp. 109-112
Author(s):  
Kira S. Koryabina ◽  
Mariya V. Sergeeva ◽  
Andrey B. Komissarov ◽  
Nataliya V. Eshchenko ◽  
Grigoriy A. Stepanov

BACKGROUND: The application of CRISPR/Cas9 is one of the most rapidly developing areas in biotechnology. This method was used to obtain clones of а human origin cell line with knockout of one or more genes of the IFITM family, representing host restriction factors for influenza infection. Amphotericin B has previously been shown to promote influenza infection by blocking IFITM3 function. AIM: The aim of this study was to evaluate the effect of amphotericin B on the sensitivity of IFITM knockout cells to influenza A virus infection. MATERIALS AND METHODS: WI-38 VA-13 cells and mutant clones with IFITM3 knockout (F3 clone) or IFITM1, IFITM3 knockout (clone E12) were infected with influenza virus A/PR/8/34 (H1N1) in the presence or absence of amphotericin B. Forty-four hours after infection, the culture medium was taken to determine the infectious activity of the virus by titration in the MDCK cell culture, as well as the hemagglutinating activity of the virus. The infected cells were stained with fluorescently labeled antibodies against the viral NP protein, and the number of NP-positive cells was determined by flow cytometry. RESULTS: The addition of amphotericin B increased the hemagglutinating and infectious activity of the virus in WI-38 VA-13cells, while the difference was insignificant for clones with IFITM gene knockout. A similar dependency was obtained for the percent of infected cells. CONCLUSIONS: Mutant cells with a knockout of one or several genes of the IFITM family were equally susceptible to influenza infection regardless of the addition of amphotericin B, which confirms the crucial importance of a defect in the IFITM3 protein in increasing the permissiveness of cells to influenza A virus.


1980 ◽  
Vol 29 (2) ◽  
pp. 719-723 ◽  
Author(s):  
C S Reiss ◽  
J L Schulman

M protein of influenza A virus was detected with rabbit antiserum by both indirect immunofluorescence and by antibody plus complement-mediated cytolysis on the cell surfaces of both productively and nonproductively infected cells. In contrast, antiserum to nucleoprotein failed to react with unfixed infected cells, but did bind to fixed infected cells, especially in the perinuclear area. Incorporation of antiserum to M protein in a T-cell-mediated cytotoxicity assay produced almost complete abrogation of lysis of H-2-compatible cells infected with an influenza A virus of a subtype which differed from that used to elicit the cytotoxic T cells. However, the antibody did not significantly block 51Cr release from cells infected with the homotypic type A influenza virus. These observations are in accord with the hypothesis that the cross-reactive cytotoxic T-cell responses seen with cells infected by heterotypic influenza A viruses are due to recognition of a common M protein.


2020 ◽  
Author(s):  
Sergej Franz ◽  
Thomas Zillinger ◽  
Fabian Pott ◽  
Christiane Schüler ◽  
Sandra Dapa ◽  
...  

AbstractInterferon-induced transmembrane (IFITM) proteins restrict infection by enveloped viruses through interfering with membrane fusion and virion internalisation. The role of IFITM proteins during alphaviral infection of human cells and viral counteraction strategies remain largely unexplored. Here, we characterized the impact of IFITM proteins and variants on entry and spread of Chikungunya virus (CHIKV) and Mayaro virus (MAYV) in human cells, and provide first evidence for a CHIKV-mediated antagonism of IFITM proteins. IFITM1, 2 and 3 restricted infection at the level of alphavirus glycoprotein-mediated entry, both in the context of direct infection and during cell-to-cell transmission. Relocalization of normally endosomal IFITM3 to the plasma membrane resulted in the loss of its antiviral activity. rs12252-C, a naturally occurring variant of IFITM3 that has been proposed to associate with severe influenza in humans, restricted CHIKV, MAYV and influenza A virus infection as efficiently as wild-type IFITM3. Finally, all antivirally active IFITM variants displayed reduced cell surface levels in CHIKV-infected cells involving a posttranscriptional process mediated by one or several non-structural protein(s) of CHIKV.


2012 ◽  
Vol 287 (22) ◽  
pp. 18366-18375 ◽  
Author(s):  
Xiaodu Wang ◽  
Xufang Deng ◽  
Wenjun Yan ◽  
Zixiang Zhu ◽  
Yang Shen ◽  
...  

2021 ◽  
Vol 10 (36) ◽  
pp. 167-169
Author(s):  
Camila Siqueira ◽  
Diogo Kuczera ◽  
Eneida Da Lozzo ◽  
Dorly Buchi ◽  
José Nelson Couceiro ◽  
...  

Introduction: Strains of macrophages, such as murine J774.G8 macrophages, are susceptible to influenza A infection [1]. One of the responses to viral infection involves the production of various types of immunostimulatory cytokines by infected cells [2]. Methods: In the present study, the macrophage strain J774.G8, maintained in RPMI medium, was submitted to treatment with 10% V/V of two different biotherapics prepared from influenza H3N2, both at 30x. Additionally, two control groups were analyzed: macrophages stimulated with water 30x and macrophages without any treatment. Biotherapics were prepared from intact H3N2 influenza virus and H3N2 inactivated by alcohol 70%. The compounding of both biotherapics followed this procedure: one part of viral particles was diluted in 9 parts of sterile distilled water. The 1:10 sample was submitted to 100 mechanical succussions using Autic® Brazilian machine, originating the first dilution, named decimal (1x). 1 ml of this solution was diluted in 9 ml of solvent and was submitted to 100 succussions, generating biotherapic 2x. This procedure was successively repeated, according to Brazilian Homeopathic Pharmacopoeia, to obtain the biotherapic 30x. By the same technique, water vehicle was prepared in the potency of 30x to be used as control. All samples were prepared under sterile and aseptic conditions, using laminar flow cabinet, class II, and were stored in the refrigerator (8ºC), to avoid microbiological contamination. J774.G8 macrophages were stimulated for 2 days, in a total of six stimuli. Immediately before infection with 25 µl of H3N2 influenza virus, the supernatants were collected and frozen at -20 ºC for later analysis. Next, 24 hours after the virus infection, the supernatants were aliquoted and frozen under the same conditions. Three independent experiments were done in triplicate. Analysis of supernatants was performed by flow cytometry using the Mouse Inflammation Kit. The cytokines detected in this experiment were IL-10, IL 12, TNF-α and MCP1. Results: In all cases, there were no significant differences compared to control groups. However, the production of TNF-α detected in macrophages treated by intact and inactivated biotherapics presented a tendency to increase after infection. In fact, similar results were previously detected in other experiments conducted only with the intact biotherapic [3]. The release of the cytokine MCP1 in all experimental situations presented a tendency to decrease after the viral infection when compared to untreated macrophages. No statistically significant difference was detected in the production of IL 12 and IL 10. These experiments will be repeated to confirm the data obtained.


2021 ◽  
Author(s):  
Tina Meischel ◽  
Svenja Fritzlar ◽  
Fernando Villalon-Letelier ◽  
Melkamu B. Tessema ◽  
Andrew G. Brooks ◽  
...  

Interferon-induced transmembrane (IFITM) proteins inhibit a broad range of enveloped viruses by blocking entry into host cells. We used an inducible overexpression system to investigate if IFITM1, IFITM2 and IFITM3 could modulate early and/or late stages of influenza A virus (IAV) or parainfluenza virus (PIV)-3 infection in human A549 airway epithelial cells. IAV and PIV-3 represent respiratory viruses which utilise distinct cellular entry pathways. We verify entry by endocytosis for IAV, whereas PIV-3 infection was consistent with fusion at the plasma membrane. Following induction prior to infection, all three IFITM proteins restricted the percentage of IAV-infected cells at 8 hours post-infection. In contrast, prior induction of IFITM1 and IFITM2 did not inhibit PIV-3 infection, although a modest reduction was observed with IFITM3. siRNA-mediated knockdown of endogenous IFITM1, IFITM2 and IFITM3 expression, in the presence or absence of pre-treatment with type I interferon, resulted in increased IAV, but not PIV-3, infection. This suggests that while all three IFITMs display antiviral activity against IAV, they do not restrict the early stages of PIV-3 infection. IAV and PIV-3 infection culminates in viral egress through budding at the plasma membrane. Inducible expression of IFITM1, IFITM2 or IFITM3 immediately after infection did not impact titres of infectious virus released from IAV or PIV-3 infected cells. Our findings show that IFITM proteins differentially restrict the early stages of infection of two respiratory viruses with distinct cellular entry pathways, but do not influence the late stages of replication for either virus. IMPORTANCE Interferon-induced transmembrane (IFITM) proteins restrict the initial stages of infection for several respiratory viruses, however their potential to modulate the later stages of virus replication has not been explored. In this study we highlight the utility of an inducible overexpression system to assess the impact of IFITM proteins on either early or late stage replication of two respiratory viruses. We demonstrate antiviral activity by IFITM1, IFITM2 and IFITM3 against influenza A virus (IAV) but not parainfluenza virus (PIV)-3 during the early stages of cellular infection. Furthermore, IFITM induction following IAV or PIV-3 infection does not restrict the late stages of replication of either virus. Our findings show that IFITM proteins can differentially restrict the early stages of infection of two viruses with distinct cellular entry pathways, yet do not influence the late stages of replication for either virus.


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