scholarly journals Transcriptome profiling and protease inhibition experiments identify proteases that activate H3N2 influenza A and influenza B viruses in murine airways

2020 ◽  
Vol 295 (33) ◽  
pp. 11388-11407 ◽  
Author(s):  
Anne Harbig ◽  
Marco Mernberger ◽  
Linda Bittel ◽  
Stephan Pleschka ◽  
Klaus Schughart ◽  
...  

Cleavage of influenza virus hemagglutinin (HA) by host proteases is essential for virus infectivity. HA of most influenza A and B (IAV/IBV) viruses is cleaved at a monobasic motif by trypsin-like proteases. Previous studies have reported that transmembrane serine protease 2 (TMPRSS2) is essential for activation of H7N9 and H1N1pdm IAV in mice but that H3N2 IAV and IBV activation is independent of TMPRSS2 and carried out by as-yet-undetermined protease(s). Here, to identify additional H3 IAV- and IBV-activating proteases, we used RNA-Seq to investigate the protease repertoire of murine lower airway tissues, primary type II alveolar epithelial cells (AECIIs), and the mouse lung cell line MLE-15. Among 13 candidates identified, TMPRSS4, TMPRSS13, hepsin, and prostasin activated H3 and IBV HA in vitro. IBV activation and replication was reduced in AECIIs from Tmprss2/Tmprss4-deficient mice compared with WT or Tmprss2-deficient mice, indicating that murine TMPRSS4 is involved in IBV activation. Multicycle replication of H3N2 IAV and IBV in AECIIs of Tmprss2/Tmprss4-deficient mice varied in sensitivity to protease inhibitors, indicating that different, but overlapping, sets of murine proteases facilitate H3 and IBV HA cleavages. Interestingly, human hepsin and prostasin orthologs did not activate H3, but they did activate IBV HA in vitro. Our results indicate that TMPRSS4 is an IBV-activating protease in murine AECIIs and suggest that TMPRSS13, hepsin, and prostasin cleave H3 and IBV HA in mice. They further show that hepsin and prostasin orthologs might contribute to the differences observed in TMPRSS2-independent activation of H3 in murine and human airways.

2019 ◽  
Vol 93 (21) ◽  
Author(s):  
Hannah Limburg ◽  
Anne Harbig ◽  
Dorothea Bestle ◽  
David A. Stein ◽  
Hong M. Moulton ◽  
...  

ABSTRACT Cleavage of influenza virus hemagglutinin (HA) by host cell proteases is essential for virus infectivity and spread. We previously demonstrated in vitro that the transmembrane protease TMPRSS2 cleaves influenza A virus (IAV) and influenza B virus (IBV) HA possessing a monobasic cleavage site. Subsequent studies revealed that TMPRSS2 is crucial for the activation and pathogenesis of H1N1pdm and H7N9 IAV in mice. In contrast, activation of H3N2 IAV and IBV was found to be independent of TMPRSS2 expression and supported by an as-yet-undetermined protease(s). Here, we investigated the role of TMPRSS2 in proteolytic activation of IAV and IBV in three human airway cell culture systems: primary human bronchial epithelial cells (HBEC), primary type II alveolar epithelial cells (AECII), and Calu-3 cells. Knockdown of TMPRSS2 expression was performed using a previously described antisense peptide-conjugated phosphorodiamidate morpholino oligomer, T-ex5, that interferes with splicing of TMPRSS2 pre-mRNA, resulting in the expression of enzymatically inactive TMPRSS2. T-ex5 treatment produced efficient knockdown of active TMPRSS2 in all three airway cell culture models and prevented proteolytic activation and multiplication of H7N9 IAV in Calu-3 cells and H1N1pdm, H7N9, and H3N2 IAV in HBEC and AECII. T-ex5 treatment also inhibited the activation and spread of IBV in AECII but did not affect IBV activation in HBEC and Calu-3 cells. This study identifies TMPRSS2 as the major HA-activating protease of IAV in human airway cells and IBV in type II pneumocytes and as a potential target for the development of novel drugs to treat influenza infections. IMPORTANCE Influenza A viruses (IAV) and influenza B viruses (IBV) cause significant morbidity and mortality during seasonal outbreaks. Cleavage of the viral surface glycoprotein hemagglutinin (HA) by host proteases is a prerequisite for membrane fusion and essential for virus infectivity. Inhibition of relevant proteases provides a promising therapeutic approach that may avoid the development of drug resistance. HA of most influenza viruses is cleaved at a monobasic cleavage site, and a number of proteases have been shown to cleave HA in vitro. This study demonstrates that the transmembrane protease TMPRSS2 is the major HA-activating protease of IAV in primary human bronchial cells and of both IAV and IBV in primary human type II pneumocytes. It further reveals that human and murine airway cells can differ in their HA-cleaving protease repertoires. Our data will help drive the development of potent and selective protease inhibitors as novel drugs for influenza treatment.


2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Jeong-Joong Yoon ◽  
Mart Toots ◽  
Sujin Lee ◽  
Myung-Eun Lee ◽  
Barbara Ludeke ◽  
...  

ABSTRACT Morbidity and mortality resulting from influenza-like disease are a threat, especially for older adults. To improve case management, next-generation broad-spectrum antiviral therapeutics that are efficacious against major drivers of influenza-like disease, including influenza viruses and respiratory syncytial virus (RSV), are urgently needed. Using a dual-pathogen high-throughput screening protocol for influenza A virus (IAV) and RSV inhibitors, we have identified N4-hydroxycytidine (NHC) as a potent inhibitor of RSV, influenza B viruses, and IAVs of human, avian, and swine origins. Biochemical in vitro polymerase assays and viral RNA sequencing revealed that the ribonucleotide analog is incorporated into nascent viral RNAs in place of cytidine, increasing the frequency of viral mutagenesis. Viral passaging in cell culture in the presence of an inhibitor did not induce robust resistance. Pharmacokinetic profiling demonstrated dose-dependent oral bioavailability of 36 to 56%, sustained levels of the active 5′-triphosphate anabolite in primary human airway cells and mouse lung tissue, and good tolerability after extended dosing at 800 mg/kg of body weight/day. The compound was orally efficacious against RSV and both seasonal and highly pathogenic avian IAVs in mouse models, reducing lung virus loads and alleviating disease biomarkers. Oral dosing reduced IAV burdens in a guinea pig transmission model and suppressed virus spread to uninfected contact animals through direct transmission. Based on its broad-spectrum efficacy and pharmacokinetic properties, NHC is a promising candidate for future clinical development as a treatment option for influenza-like diseases.


2021 ◽  
Vol 35 (S1) ◽  
Author(s):  
Anne Harbig ◽  
Marco Mernberger ◽  
Linda Bittel ◽  
Stephan Pleschka ◽  
Klaus Schughart ◽  
...  

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 509 ◽  
Author(s):  
Meenakshi Tiwary ◽  
Robert J. Rooney ◽  
Swantje Liedmann ◽  
Kim S. LeMessurier ◽  
Amali E. Samarasinghe

Eosinophils, previously considered terminally differentiated effector cells, have multifaceted functions in tissues. We previously found that allergic mice with eosinophil-rich inflammation were protected from severe influenza and discovered specialized antiviral effector functions for eosinophils including promoting cellular immunity during influenza. In this study, we hypothesized that eosinophil responses during the early phase of influenza contribute to host protection. Using in vitro and in vivo models, we found that eosinophils were rapidly and dynamically regulated upon influenza A virus (IAV) exposure to gain migratory capabilities to traffic to lymphoid organs after pulmonary infection. Eosinophils were capable of neutralizing virus upon contact and combinations of eosinophil granule proteins reduced virus infectivity through hemagglutinin inactivation. Bi-directional crosstalk between IAV-exposed epithelial cells and eosinophils occurred after IAV infection and cross-regulation promoted barrier responses to improve antiviral defenses in airway epithelial cells. Direct interactions between eosinophils and airway epithelial cells after IAV infection prevented virus-induced cytopathology in airway epithelial cells in vitro, and eosinophil recipient IAV-infected mice also maintained normal airway epithelial cell morphology. Our data suggest that eosinophils are important in the early phase of IAV infection providing immediate protection to the epithelial barrier until adaptive immune responses are deployed during influenza.


2020 ◽  
Author(s):  
Weijia Wang ◽  
Ying Li ◽  
Xiaoyan Qu ◽  
Dong Shang ◽  
Qiaohong Qin ◽  
...  

Abstract BACKGROUND The IL-17 superfamily, which mediates cross-talk between the adaptive and innate immune systems, has been associated with severity of asthma. The role of miRNAs in the disease has been paid much attention. To explore the roles of IL-17 in asthma and the relationship between IL-17 and miRNAs, we used a model of severe asthma driven by chronic respiratory exposure to house dust mite (HDM) exposure in wild type and IL-17KO mice, followed with miRNA profiling assays and analysis.METHODS Male and female C57BL/6 mice (6-8 weeks old) and IL-17KO mice (C57BL/6 background) were exposed to purified HDM extract intranasally for 5 days/week for 5 consecutive weeks. Sterile saline was used as the control. The parameters including airway responsiveness, inflammatory cells in bronchoalveolar lavage fluid (BALF), airway smooth muscle bundle, collagen deposition, and cytokine levels in BALF were examined. The miRNA profile of mouse lung tissue was analyzed by microarray assays. The dysregulation of miRNA related to IL-17 and asthma was validated by qRT-PCR. The in vitro cell culture experiment was performed to confirm the relationship between IL-17 and selected miRNA. The regulation of miRNA on predicted target gene was validated by administration of miRNA mimics. RESULTS The expression of IL-17A significantly increased in wild type (WT) mice with HDM exposure compared to the control mice. IL-17 deficiency did not reduce airway hyper responsiveness (AHR) induced by HDM exposure. In comparison to HDM-exposed WT mice, BALF neutrophils in IL-17KO mice were significantly decreased. In WT mice, HDM exposure led to increased expression of IL-4 and KC, which was significantly decreased in IL-17KO mice. Furthermore, under HDM exposure, significantly less airway smooth muscle mass and collagen deposition was found in IL-17KO mice compared to WT mice. In the dysregulated miRNAs, the decreased expression of miR-365-3p in HDM-exposed WT mice was validated, and its expression recovered in IL-17KO mice. Furthermore, miR-365-3p was decreased in mouse alveolar epithelial cells by IL-17 treatment. The transfection of miR-365-3p mimics decreased the expression of predicted target gene ARRB2.


2020 ◽  
Vol 58 (6) ◽  
Author(s):  
Kathleen A. Stellrecht ◽  
Jesse L. Cimino ◽  
Vincente P. Maceira

ABSTRACT Nucleic acid amplification tests, such as PCR, are the method of choice for respiratory virus testing, due to their superior diagnostic accuracy and fast turnaround time. The Panther Fusion (Fusion; Hologic) system has an array of highly sensitive in vitro diagnostic (IVD) real-time PCR assays for respiratory viruses, including an assay for influenza A (FluA) virus, influenza B (FluB) virus, and respiratory syncytial virus (RSV) (FFABR assay). The Fusion system has Open Access functionality to perform laboratory-developed tests (LDTs) alongside IVD assays. We developed two LDTs for FluA virus strain typing on the Panther Fusion instrument, enabling side-by-side testing with the FFABR assay. The LDT-FAST assay uses proprietary primers and probes designed by Hologic for the Prodesse ProFAST+ (PFAST) assay. The exWHO-FAST assay is an expanded redesign of the WHO-recommended reverse transcriptase PCRs (RT-PCRs). To evaluate the performance of these two LDTs, 110 FluA virus-positive samples were tested. Of these, 104 had been subtyped previously; 54 were H3, 46 were 09H1, and 4 were fsH1. All were appropriately subtyped by both LDTs. Of the untyped FluA virus samples, three were subtyped as H3 by both LDTs and two were subtyped as H3 by the LDT-FAST assay only. The sample not subtyped by either LDT was retested with the FFABR assay and was now negative. Limit-of-detection (LOD) analyses were performed with five FluA virus strains. The LDT-FAST LODs were similar to the FFABR assay LODs, while the exWHO-FAST LODs were higher for two H3N2 strains, findings that were explained by analysis of primer/probe homology. In conclusion, either FluA virus typing assay would be a valuable complement to the Panther Fusion respiratory menu given the performance of these LDTs, the system’s full automation, and the ability to split eluates for both IVD and LDT testing.


1947 ◽  
Vol 86 (5) ◽  
pp. 357-366 ◽  
Author(s):  
George K. Hirst

1. When strains of influenza A virus which have been isolated in chick embryos are introduced into the mouse lung, the virus multiplies readily and achieves initially a titer which is as high as is even obtained, even after repeated passage. The high initial titer of virus may be unaccompanied by any lethal or visible pathogenic effects; but with four or five mouse passages the agent becomes lethal in high titer and causes extensive pulmonary consolidation, though its capacity to multiply in the lung has not increased. In one example the adaptation to mouse lung was accompanied by increasing capacity to agglutinate guinea pig red cells without a corresponding increase in agglutinating power for chicken cells. Influenza B virus, in preliminary tests, did not behave in a similar fashion. 2. The adaptation of influenza A virus to mice is accompanied by changes in antigenic pattern, as detected by cross-tests with the agglutination inhibition method. Two strains, initially similar, with passage, changed in pattern along divergent paths so that they became not only unlike the parent strains but unlike each other. This finding has important implications for the interpretation of the strain difference problem in human influenza.


1949 ◽  
Vol 90 (4) ◽  
pp. 321-334 ◽  
Author(s):  
Robert R. Wagner ◽  
Ivan L. Bennett ◽  
Virgil S. LeQuire

The intravenous injection of the PR8 strain of influenza A virus, the Lee strain of influenza B, and the "B" strain of Newcastle disease virus produces fever in rabbits. This phenomenon has been studied in relation to certain in vitro properties of these viruses. Saline suspensions of virus prepared by centrifugation or elution from chicken erythrocytes produced fever. Fluids from which most of the virus particles had been removed were non-pyrogenic. Exposure to temperatures which destroyed the infectivity of the virus for chick embryos did not prevent fever. However, heating sufficient to destroy the hemagglutinin also rendered virus non-pyrogenic. The injection of erythrocytes onto which virus had been adsorbed produced fever. Heated virus adsorbed onto erythrocytes, which failed to elute, produced no elevation of temperature, although heated virus alone was pyrogenic. Neutralization of virus with specific immune serum prevented fever. Antipyrine was capable of abolishing the febrile response to virus. Certain differences between the febrile response in rabbits to the injection of viruses and that following bacterial pyrogens were noted. The period between injection and beginning of temperature rise is longer with virus than with bacterial pyrogens. Relatively low temperatures inactivate the fever-producing capacity of viruses, whereas bacterial pyrogens withstand prolonged autoclaving, and the neutralization of viral fever by specific immune serum contrasts sharply with the failure of antibody to affect the response to bacterial pyrogens. Certain previous observations on the lymphopenia produced in rabbits by the injection of influenzal viruses were confirmed. The capacity of virus preparations to induce fever in rabbits closely parallels their capacity to induce lymphopenia. It was concluded that the fever-producing property of influenzal viruses is closely associated with the capacity to agglutinate erythrocytes.


2021 ◽  
Author(s):  
Joanne M Del Rosario ◽  
Kelly da Costa ◽  
Benedikt Asbach ◽  
Francesca Ferrara ◽  
Matteo Ferrari ◽  
...  

We have developed an influenza hemagglutinin (HA) pseudotype library encompassing Influenza A subtypes HA1-18, and Influenza B subtypes (both lineages) to be employed in influenza pseudotype microneutralization (pMN) assays. The pMN is highly sensitive and specific for de-tecting virus-specific neutralizing antibodies against influenza viruses and can be used to assess antibody functionality in vitro. Here we show the production of these viral HA pseudotypes and their employment as substitutes for wildtype viruses in influenza serological and neutralization assays. We demonstrate its utility in detecting serum response to vaccination with the ability to evaluate cross-subtype neutralizing responses elicited by specific vaccinating antigens. Our findings may inform further pre-clinical studies involving immunization dosing regimens in mice and may help in the creation and selection of better antigens for vaccine design. These HA pseudotypes can be harnessed to meet strategic objectives that contribute to the strengthening of global influenza surveillance, expansion of seasonal influenza prevention and control policies, and strengthening pandemic preparedness and response.


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