Comprehensive analysis of host gene expression in Autographa californica nucleopolyhedrovirus-infected Spodoptera frugiperda cells
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ABSTRACT: Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) is the best-studied baculovirus and most commonly used virus vector for baculovirus expression vector systems. The effect of AcMNPV infection on host cells is incompletely understood. A microarray based on Spodoptera frugiperda ESTs was used to investigate the impact of AcMNPV on host gene expression in cultured S. frugiperda, Sf21 cells. Most host genes were down-regulated over the time course of infection, although a small number were up-regulated. The most highly up-regulated genes encoded heat shock protein 70s and several poorly characterized proteins. Regulated genes with the highest score identified by functional annotation clustering included primarily products required for protein expression and trafficking in the ER and golgi. All were significantly down-regulated by approximately 12h post-infection. Microarray data were validated by qRT-PCR. This study provides the first comprehensive host transcriptome overview of Sf21 cells during AcMNPV infection. Host gene expression of the Sf21 cells was measured in AcMNPV mock-infected Sf21cells as well as AcMNPV-infected Sf21 cells at 6, 12, and 24 hours post infection (hpi). Four independent experiments were performed at each time (6, 12, and 24 hpi) using different donors for each experiment. Only two 24 hour sample data sets were used in the final analysis as two did not meet QC criteria.
Project description:Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) is the best-studied baculovirus and most commonly used virus vector for baculovirus expression vector systems. The effect of AcMNPV infection on host cells is incompletely understood. A microarray based on Spodoptera frugiperda ESTs was used to investigate the impact of AcMNPV on host gene expression in cultured S. frugiperda, Sf21 cells. Most host genes were down-regulated over the time course of infection, although a small number were up-regulated. The most highly up-regulated genes encoded heat shock protein 70s and several poorly characterized proteins. Regulated genes with the highest score identified by functional annotation clustering included primarily products required for protein expression and trafficking in the ER and golgi. All were significantly down-regulated by approximately 12h post-infection. Microarray data were validated by qRT-PCR. This study provides the first comprehensive host transcriptome overview of Sf21 cells during AcMNPV infection.
Project description:MicroRNAs (miRNAs) as small non-coding RNAs play important roles in many biological processes such as development, cell signalling and immune response. Studies also suggest that miRNAs are important in host–virus interactions where the host limits virus infection by differentially expressing miRNAs that target essential viral genes. Here, we identified conserved and new miRNAs from Spodoptera frugiperda cells (Sf9) using a combination of deep sequencing and bioinformatics as well as experimental approaches. S. frugiperda miRNAs share common features of miRNAs in other organisms, such as uracil (U) at the 59 end of miRNA. The 59 ends of the miRNAs were more conserved than the 39 ends, revealing evolutionary protection of the seed region in miRNAs. The predominant miRNAs were found to be conserved among arthropods. The majority of homologous miRNAs were found in Bombyx mori, with 76 of the 90 identified miRNAs. We found that seed shifting and arm switching have happened in this insect’s miRNAs. Expression levels of the majority of miRNAs changed following baculovirus infection. Results revealed that baculovirus infection mainly led to an overall suppression of cellular miRNAs. We found four different genes being regulated by sfr-miR-184 at the post-transcriptional level. The data presented here further support conservation of miRNAs in insects and other organisms. In addition, the results reveal a differential expression of host miRNAs upon baculovirus infection, suggesting their potential roles in host–virus interactions. Seed shifting and arm switching happened during evolution of miRNAs in different insects and caused miRNA diversification, which led to changes in the target repository of miRNAs. Identification of miRNA and other small non coding RNA in NPV infected Sf9 cells
Project description:MicroRNAs (miRNAs) as small non-coding RNAs play important roles in many biological processes such as development, cell signalling and immune response. Studies also suggest that miRNAs are important in host–virus interactions where the host limits virus infection by differentially expressing miRNAs that target essential viral genes. Here, we identified conserved and new miRNAs from Spodoptera frugiperda cells (Sf9) using a combination of deep sequencing and bioinformatics as well as experimental approaches. S. frugiperda miRNAs share common features of miRNAs in other organisms, such as uracil (U) at the 59 end of miRNA. The 59 ends of the miRNAs were more conserved than the 39 ends, revealing evolutionary protection of the seed region in miRNAs. The predominant miRNAs were found to be conserved among arthropods. The majority of homologous miRNAs were found in Bombyx mori, with 76 of the 90 identified miRNAs. We found that seed shifting and arm switching have happened in this insect’s miRNAs. Expression levels of the majority of miRNAs changed following baculovirus infection. Results revealed that baculovirus infection mainly led to an overall suppression of cellular miRNAs. We found four different genes being regulated by sfr-miR-184 at the post-transcriptional level. The data presented here further support conservation of miRNAs in insects and other organisms. In addition, the results reveal a differential expression of host miRNAs upon baculovirus infection, suggesting their potential roles in host–virus interactions. Seed shifting and arm switching happened during evolution of miRNAs in different insects and caused miRNA diversification, which led to changes in the target repository of miRNAs.
Project description:Differential expression was determined in Calu-3 cells between mock infected and infection with either Human coronavirus EMC and SARS coronavirus at different times post infection. Calu-3 2B4 cells were infected with Human Coronavirus EMC 2012 (HCoV-EMC) or mock infected. Samples were collected 0, 3, 7, 12, 18 and 24 hpi. There are 3 mock and 3 infected replicates for each time point, except for 12 hpi for which there are only 2 infected replicates (one replicate did not pass RNA quality check). There were no mock sampes at 18 hpi, and therefore infected samples at 18 hpi were compared with mocks at 24 hpi. For direct comparison with SARS-CoV infected cells, raw data from HCoV-EMC experiments were quantile normalized together with the SARS-CoV dataset (GEO Series accession number GSE33267).
Project description:Background: The recent emergence of a novel coronavirus in the Middle East (designated MERS-CoV) is a reminder of the zoonotic potential of coronaviruses and the severe disease these etiologic agents can cause in humans. Clinical features of Middle East respiratory syndrome (MERS) include severe acute pneumonia and renal failure that is highly reminiscent of severe acute respiratory syndrome (SARS) caused by SARS-CoV. The host response is a key component of highly pathogenic respiratory virus infection. Here, we computationally analyzed gene expression changes in a human airway epithelial cell line infected with two genetically distinct MERS-CoV strains obtained from human patients, MERS-CoV-EMC (designated EMC) and MERS-CoV-London (designated LoCoV). Results: Using topological techniques, such as persistence homology and filtered clustering, we characterized the host response system to the different MERS-CoVs, with LoCoV inducing early kinetic changes, between 3 and 12 hours post infection, compared to EMC. Robust transcriptional changes distinguished the two MERS-CoV strains predominantly at the late time points. Combining statistical analysis of infection and cytokine-stimulated treatment transcriptomics, we identified differential innate and pro-inflammatory responses between the two virus strains, including up-regulation of extracellular remodeling genes following LoCoV infection and differential pro-inflammatory responses between the two strains. Conclusions: These transcriptional differences may be the result of amino acid differences in viral proteins known to modulate innate immunity against MERS infection. Triplicate wells of Calu-3 2B4 cells were infected with Human Coronavirus EMC 2012 (HCoV-EMC) or time-matched mock infected. Cells were harvested at 0, 3, 7, 12, 18 and 24 hours post-infection (hpi), RNA extracted and transcriptomics analyzed by microarray.
Project description:To combat virus infections, which are major human killers, a deeper understanding of how viruses reprogram their hosts to create optimal production of progeny is needed. Most knowledge on the regulation of cellular gene expression during adenovirus infection is derived from studies of mRNA expression. Here, we investigated the changes in cellular protein expression during the late phase of adenovirus type 2 (Ad2) infection of primary human cells by stable isotope labeling in cell culture (SILAC) with subsequent liquid chromatography-high resolution tandem mass spectrometric (LC-MS/MS) analysis using a Q-Exactive Orbitrap instrument. Cells were in-depth evaluated 24 and 36 hours post infection (hpi) and two biological replicates were investigated using swapped labeling. In total, 2648 and 2394 proteins were quantified at 24 and 36 hpi, respectively. Among them, 659 and 645 were deregulated more than 1.6-fold at the two time points, and approximately 80% of them had sustained regulation from 24 to 36 hpi. For the deregulated genes the change in protein expression was compared with that of RNA expression using cDNA sequencing data from the same time points of infection. The comparison revealed a surprisingly low correlation (r = 0.3). Consistency between changes in RNA and protein expression was observed for approximately 30% of the genes, whereas a majority showed either divergent or opposite expression profiles. The deregulated proteins were subjected to pathway and biological function analysis using bioinformatics tools. A surprising observation was that proteins related to carbohydrate metabolism were up-regulated at the protein level but unchanged at the RNA level whereas histone proteins were down-regulated at the protein level but up-regulated at the RNA level. Our results show that regulation of cellular gene expression in the response to viral infection is more complex than hitherto believed and several examples of posttranscriptional regulation of gene expression were observed. The results contribute to our understanding of host cell gene regulation during infection at a deeper level.
Project description:To combat virus infections, which are major human killers, a deeper understanding of how viruses reprogram their hosts to create optimal production of progeny is needed. Most knowledge on the regulation of cellular gene expression during adenovirus infection is derived from studies of mRNA expression. Here, we investigated the changes in cellular protein expression during the early phase of adenovirus type 2 (Ad2) infection of primary human cells by stable isotope labeling in cell culture (SILAC) with subsequent liquid chromatography-high resolution tandem mass spectrometric (LC-MS/MS) analysis using a Q-Exactive Orbitrap instrument. Cells were in-depth evaluated 6 and 12 hours post infection (hpi) and two biological replicates were investigated using swapped labeling. In total, 2027 and 2150 proteins were quantified at 6 and 12 hpi, respectively. Among them, 431 and 544 were deregulated more than 1.5-fold at the two time points. For the deregulated proteins the change in protein expression was compared with that of late phase of infection (see PXD004095). Pathway analysis showed that De novo purine and pyrimidine biosynthesis, Glycolysis and Cytoskeletal regulation by Rho GTPase pathways are activated early during the infection, while the inactivation of the Integrin signalling pathway starts between 6 and 12 hpi. The transcription factor MYC was predicted to be activated with time, and the phosphopeptide analysis revealed the up-regulation of phosphosites related with glycolysis or cytoskeletal reorganization. These results complement the previous knowledge obtained from transcriptomic data, and show novel and specific aspects of how adenovirus influence host cell gene expression at the protein level.The results contribute to our understanding of host cell gene regulation during infection at a deeper level.
Project description:Enterovirus 71 (EV71) is one of the leading causes of hand, foot and mouth disease with neurological complications in some cases. To study the pathogenesis of EV71 infection, large scale analyses of EV71 infected cells have been performed. However, most of these studies employed rhabdomyosarcoma (RD) cells or used transcriptomic strategy. Here, we performed SILAC-based quantitative proteomic analysis of EV71-infected U251 cells, a human glioma cell line. A total of 3,125 host proteins were quantified, 451 of which were differentially regulated as a result of EV71 infection at 8 hpi or 20 hpi or both.
Project description:Over the past decades, Helicoverpa armigera nucleopolyhedrovirus (HearNPV) has been widely used for biocontrol of cotton bollworm, which is one of the most destructive pest insects in agriculture worldwide. However, the molecular mechanism underlying the interaction between HearNPV and host insects remains poorly understood. In this study, high throughput RNA-sequencing was integrated with label-free quantitative proteomics analysis to examine the dynamics of gene expression in the fat body of H. armigera larvae in response to challenge with HearNPV. RNA-sequencing-based transcriptomic analysis indicated that host gene expression was substantially altered, yielding 3,850 differentially expressed genes (DEGs), while no global transcriptional shut-off effects were observed in the fat body. Among the DEGs, 60 immunity-related genes were down-regulated after baculovirus infection, a finding that was consistent with the results of quantitative real-time RT-PCR (qRT-PCR). Gene ontology and functional classification demonstrated that the majority of down-regulated genes were enriched in gene cohorts involved in energy, carbohydrate, and amino acid metabolic pathways. Proteomics analysis identified differentially expressed proteins in the fat body, among which 76 were up-regulated, whereas 373 were significantly down-regulated upon infection. The down-regulated proteins are involved in metabolic pathways such as energy metabolism, carbohydrate metabolism (CM), and amino acid metabolism, in agreement with the RNA-seq data. Furthermore, correlation analysis suggested a strong association between the mRNA level and protein abundance in the H. armigera fat body. More importantly, the predicted gene interaction network indicated that a large subset of metabolic networks was significantly negatively regulated by viral infection, including CM-related enzymes such as aldolase, enolase, malate dehydrogenase and triose-phosphate isomerase. Taken together, transcriptomic combined with proteomic data elucidated that baculovirus established systemic infection of host larvae, and manipulated the host mainly by suppressing the host immune response and down-regulating metabolism to allow viral self-replication and proliferation. Therefore, this study provided important insights into the mechanism of host-baculovirus interaction.
Project description:Purpose of this experiment was to further understand how innate immune defenses impact host response and West Nile virus tissue tropism. This study examined host-transcriptional response to West Nile virus in permissive and nonpermissive tissues using wildtype mice and mice with genetically altered interferon signaling pathways. Age-matched six to twelve week old mice were inoculated subcutaneously in the left rear footpad with 100 PFU of West Nile virus isolate TX 2002-HC (WNV-TX) in a 10 microL inoculum diluted in Hanks balanced salt solution (HBSS) supplemented with 1% heat-inactivated FBS. Mice were monitored daily for morbidity and mortality. Expression oligonucleotide arrays were performed on RNA isolated from spleen and liver tissues from strain and time-matched mock infected mice (n=2) and WNV-TX infected wild type (WT; n=3; day 4 post-infection), Ips-1-/-(n=3; day 4 post-infection), Ifnar-/- (n=3; day 2 post-infection), and Ips-1-/-xIfnar-/- (DKO; n=3; day 4 post-infection) mice.