Project description:We defined the major transcriptional responses in primary human bronchial epithelial cells (HBECs) after either infection with influenza or treatment with relevant ligands. We used four different strategies, each highlighting distinct aspects of the response. (1) cells were infected with the wild-type PR8 influenza virus that can mount a complete replicative cycle. (2) cells were transfected with viral RNA (‘vRNA’) isolated from influenza particles. This does not result in the production of viral proteins or particles and identifies the effect of RNA-sensing pathways (e.g., RIG-I.). (3) Cells were treated with interferon beta (IFNb), to distinguish the portion of the response which is mediated through Type I IFNs. (4) Cells were infected with a PR8 virus lacking the NS1 gene (‘DNS1’). The NS1 protein normally inhibits vRNA- or IFNb-induced pathways, and its deletion can reveal an expanded response to infection.
Project description:We defined the major transcriptional responses in primary human bronchial epithelial cells (HBECs) after either infection with influenza or treatment with relevant ligands. We used four different strategies, each highlighting distinct aspects of the response. (1) cells were infected with the wild-type PR8 influenza virus that can mount a complete replicative cycle. (2) cells were transfected with viral RNA (âvRNAâ) isolated from influenza particles. This does not result in the production of viral proteins or particles and identifies the effect of RNA-sensing pathways (e.g., RIG-I.). (3) Cells were treated with interferon beta (IFNb), to distinguish the portion of the response which is mediated through Type I IFNs. (4) Cells were infected with a PR8 virus lacking the NS1 gene (âDNS1â). The NS1 protein normally inhibits vRNA- or IFNb-induced pathways, and its deletion can reveal an expanded response to infection. HBECs were stimulated with a 15 minute pulse of 1000U/ml IFNÃ (PBL, Piscataway, NJ), 100ng/ml vRNA (purified directly from PR8 virus) with LTX transfection reagent (Invitrogen; Carlsbad, California), wild type H1N1 influenza (A/PR/8/34) or ?NS1 virus (PR8 with a deleted NS1 gene, gift from Dr. Garcia-Sastre). Viruses were used at a multiplicity of infection (moi) of 5. Control samples were incubated with media or LTX under the same conditions. Cells were washed, supplemented with warm media and harvested at 11 timepoints (0, .25, .5, 1, 1.5, 2, 4, 6, 8, 12, and 18 hours post-treatment). HBECs were seeded in 6 well plates at a concentration of 250,000/well 18 hours prior to stimultaion. Cells were stimulated with a 15 minute pulse of IFNb, vRNA, infected with PR8 influenza or NS1 deleted influenza, or mock treated
Project description:Viral infections facilitate bacterial trafficking to the lower respiratory tract resulting in bacterial viral co infections. Bacterial dissemination to the lower respiratory tract is enhanced by influenza A virus induced epithelial cell damage and dysregulation of immune responses. Epithelial cells act as the first line of defense and detect pathogens by a high variety of pattern recognition receptors. The post translational modification ubiquitin is involved in almost every cellular process. Moreover, ubiquitination contributes to the regulation of host immune responses, influenza A virus uncoating and transport within host cells. We applied proteomics with a special focus on ubiquitination to assess the impact of single bacterial and viral as well as bacterial viral co-infections on bronchial epithelial cells. We used Tandem Ubiquitin Binding Entities to enrich polyubiquitinated proteins and assess changes in the ubiquitinome. Infecting 16HBE cells with Streptococcus pyogenes led to an increased abundance of proteins related to mitochondrial translation and energy metabolism in proteome and ubiquitinome. In contrast, influenza A virus infection mainly altered the ubiquitinome. Co-infections had no additional impact on protein abundances or affected pathways. Changes in protein abundance and enriched pathways were assigned to imprints of both infecting pathogens.
Project description:Airway epithelial cells are the initial site of infection with influenza viruses. The innate immune responses of airway epithelial cells to infection have the potential to limit virus replication and induce effective adaptive immune responses. However, relatively little is known about the importance of this innate anti-viral response to infection. Avian influenza viruses are a potential source of future pandemics, therefore it is critical to examine the effectiveness of the host anti-viral system to different influenza viruses. We used a human influenza (H3N2) and a low pathogenic avian influenza (H11N9) to assess and compare the anti-viral responses of bronchial epithelial cells (BECs). After infection, the H3N2 virus replicated more effectively than the H11N9 strain in BECs. This was not due to differential expression of different sialic acid residues on BECs but was attributed to the interference of the host anti-viral responses by H3N2. The H3N2 strain induced a delay in anti-viral signaling and impaired release of type I and type III interferons (IFNs) compared to the H11N9 virus. We then transfected the gene encoding for non-structural (NS) 1 protein into the BECs and the H3N2 NS1 induced a greater inhibition of anti-viral responses compared to the H11N9 NS1. While the low pathogenic avian influenza virus was capable of infecting BECs, the human influenza virus replicated more effectively than avian influenza virus in BECs and this may be at least in part due to a differential ability of the two NS1 proteins to inhibit anti-viral responses. This suggests that the subversion of human anti-viral responses may be an important requirement for influenza viruses to adapt to the human host and induce disease.
Project description:A. Esteban Hernandez-Vargas & Michael Meyer-Hermann. Innate Immune System Dynamics to Influenza Virus. IFAC Proceedings Volumes 45, 18 (2012).
The understanding of how influenza virus infection activates the immune system is crucial to designing prophylactic and therapeutic strategies against the infection. Nevertheless, the immune response to influenza virus infection is complex and remains largely unknown. In this paper we focus in the innate immune response to influenza virus using a mathematical model, based on interferon-induced resistance to infection of respiratory epithelial cells and the clearance of infected cells by natural killers. Simulation results show the importance of IFN-I to prevent new infections in epithelial cells and to stop the viral explosion during the first two days after infection. Nevertheless, natural killers response might be the most relevant for the first depletion in viral load due to the elimination of infected cells. Based on the reproductive number, the innate immune response is important to control the infection, although it would not be enough to clear completely the virus. The effective coordination between innate and adaptive immune response is essential for the virus eradication.
Project description:Virus and host factors contribute to cell-to-cell variation in viral infection and determine the outcome of the overall infection. However, the extent of the variability at the single cell level and how it impacts virus-host interactions at a systems level are not well understood. To characterize the dynamics of viral transcription and host responses, we used single-cell RNA sequencing to quantify at multiple time points the host and viral transcriptomes of human A549 cells and primary bronchial epithelial cells infected with influenza A virus. We observed substantial variability of viral transcription between cells, including the accumulation of defective viral genomes (DVGs) that impact viral replication. We show a correlation between DVGs and viral-induced variation of the host transcriptional program and an association between differential induction of innate immune response genes and attenuated viral transcription in subpopulations of cells. These observations at the single cell level improve our understanding of the complex virus-host interplay during influenza infection.
Project description:Human rhinovirus and influenza virus infections of the upper airway lead to colds and the flu and can trigger exacerbations of lower airway diseases including asthma and chronic obstructive pulmonary disease. Despite modest advances in the diagnosis and treatment of infections by these viruses, novel diagnostic and therapeutic targets are still needed to differentiate between the cold and the flu, since the clinical course of influenza can be severe while that of rhinovirus is usually more mild. In our investigation of influenza and rhinovirus infection of human respiratory epithelial cells, we used a systems approach to identify the temporally changing patterns of host gene expression from these viruses. After infection of human bronchial epithelial cells (BEAS-2B) with rhinovirus, influenza virus or co-infection with both viruses, we studied the time-course of host gene expression changes over three days. From these data, we constructed a transcriptional regulatory network model that revealed shared and unique host responses to these viral infections such that after a lag of 4-8 hours, most cell host responses were similar for both viruses, while divergent host cell responses appeared after 24-48 hours. The similarities and differences in gene expression after epithelial infection of rhinovirus, influenza virus, or both viruses together revealed qualitative and quantitative differences in innate immune activation and regulation. These differences help explain the generally mild outcome of rhinovirus infections compared to influenza infections which can be much more severe. Human bronchial epithelial cells (BEAS-2B) were infected with rhinovirus, influenza virus or both viruses and RNAs were then profiled at 10 time points (2, 4, 6, 8, 12, 24, 26, 48, 60 and 72hrs)
Project description:Long noncoding RNAs (lncRNAs) are a newer class of noncoding transcripts identified as key regulators of biological processes. Here we aimed to identify novel lncRNA targets that play critical roles in major human respiratory viral infections by systematically mining large-scale transcriptomic datasets. Using bulk RNA-sequencing (RNA-seq) analysis, we identified a previously uncharacterized lncRNA, named virus inducible lncRNA modulator of interferon response (VILMIR), that was consistently upregulated after in vitro influenza infection across multiple human epithelial cell lines and influenza A virus subtypes. VILMIR was also upregulated after SARS-CoV-2 and RSV infections in vitro. We experimentally confirmed the response of VILMIR to influenza infection and interferon-beta (IFN-β) treatment in the A549 human epithelial cell line and found the expression of VILMIR was robustly induced by IFN-β treatment in a dose and time-specific manner. Single cell RNA-seq analysis of bronchoalveolar lavage fluid (BALF) samples from COVID-19 patients uncovered that VILMIR was upregulated across various cell types including at least five immune cells. The upregulation of VILMIR in immune cells was further confirmed in the human T cell and monocyte cell lines, SUP-T1 and THP-1, after IFN-β treatment. Finally, we found that knockdown of VILMIR expression reduced the magnitude of host transcriptional responses to both IFN-β treatment and influenza A virus infection in A549 cells. Together, our results show that VILMIR is a novel interferon-stimulated gene (ISG) that regulates the host interferon response and may be a potential therapeutic target for human respiratory viral infections upon further mechanistic investigation.
Project description:Pandemic H1N1 influenza A (H1N1pdm) elicits stronger pulmonary inflammation than previously circulating seasonal H1N1 influenza A (sH1N1), yet mechanisms of inflammatory activation in respiratory epithelial cells during H1N1pdm infection are unclear. We investigated host responses to H1N1pdm / sH1N1 infection and virus entry mechanisms in primary human bronchial epithelial cells in vitro. H1N1pdm infection rapidly initiated a robust inflammatory gene signature (3 h post-infection) not elicited by sH1N1 infection. Protein secretion inhibition had no effect on gene induction. Infection with membrane fusion deficient H1N1pdm failed to induce robust inflammatory gene expression which was rescued with restoration of fusion ability, suggesting H1N1pdm directly triggered the inflammatory signature downstream of membrane fusion. Investigation of intra-virion components revealed H1N1pdm viral RNA (vRNA) triggered a stronger inflammatory phenotype than sH1N1 vRNA. Thus, our study is first to report H1N1pdm induces greater inflammatory gene expression than sH1N1 in vitro due to direct virus-epithelial cell interaction. Total RNA obtained from Normal Human Bronchial Epithelial Cells (NHBEC) at 3 hours or 24 hours post-infection with either 0.9 MOI A/Mexico/4108/2009 (H1N1) or 0.9 MOI A/Brisbane/59/2007 (H1N1). Total RNA was also collected at 0 hours from uninfected NHBEC for each infection. Changes in gene expression relative to uninfected cells were then investigated.
Project description:Viral infections facilitate bacterial trafficking to the lower respiratory tract resulting in bacterial viral co infections. Bacterial dissemination to the lower respiratory tract is enhanced by influenza A virus induced epithelial cell damage and dysregulation of immune responses. Epithelial cells act as the first line of defense and detect pathogens by a high variety of pattern recognition receptors. The post translational modification ubiquitin is involved in almost every cellular process. Moreover, ubiquitination contributes to the regulation of host immune responses, influenza A virus uncoating and transport within host cells. We applied proteomics with a special focus on ubiquitination to assess the impact of single bacterial and viral as well as bacterial viral co-infections on bronchial epithelial cells. We used Tandem Ubiquitin Binding Entities to enrich polyubiquitinated proteins and assess changes in the ubiquitinome. Infecting 16HBE cells with Streptococcus pyogenes led to an increased abundance of proteins related to mitochondrial translation and energy metabolism in proteome and ubiquitinome. In contrast, influenza A virus infection mainly altered the ubiquitinome. Co-infections had no additional impact on protein abundances or affected pathways. Changes in protein abundance and enriched pathways were assigned to imprints of both infecting pathogens.