Label-free quantitative proteomics reveals regulation of interferon-induced protein with tetratricopeptide repeats 3 (IFIT3) and 5'-3'-exoribonuclease 2 (XRN2) during respiratory syncytial virus infection

Molecular markers of type II alveolar epithelial cells in acute lung injury by bioinformatics analysis

In this study, we aimed to identify molecular markers associated with type II alveolar epithelial cell injury in acute lung injury (ALI) models using bioinformatics methods. The objective was to provide new insights for the diagnosis and treatment of ALI/ARDS. We downloaded RNA SEQ datasets (GSE109913, GSE179418, and GSE119123) from the Gene Expression Omnibus (GEO) and used R language package to screen differentially expressed genes (DEGs). DEGs were annotated using Gene Ontology (GO), and their pathways were analyzed using Kyoto Encyclopedia of Genes and Genomes (KEGG). DEGs were imported into the STRING database and analyzed using Cytoscape software to determine the protein network of DEGs and calculate the top 10 nodes for the hub genes. Finally, potential therapeutic drugs for the hub genes were predicted using the DGIdb database. We identified 78 DEGs, including 70 up-regulated genes and 8 down-regulated genes. GO analysis revealed that the DEGs were mainly involved in biological processes such as granulocyte migration, response to bacterial-derived molecules, and cytokine-mediated signaling pathways. Additionally, they had cytokine activity, chemokine activity, and receptor ligand activity, and functioned in related receptor binding, CXCR chemokine receptor binding, G protein-coupled receptor binding, and other molecular functions. KEGG analysis indicated that the DEGs were mainly involved in TNF signaling pathway, IL-17 signaling pathway, NF-κB signal pathway, chemokine signal pathway, cytokine-cytokine receptor interaction signal pathway, and others. We identified eight hub genes, including IRF7, IFIT1, IFIT3, PSMB8, PSMB9, BST2, OASL2, and ZBP1, which were all up-regulated genes. We identified several hub genes of type II alveolar epithelial cells in ALI mouse models using bioinformatics analysis. These results provide new targets for understanding and treating of ALI.

The emerging roles of IFIT3 in antiviral innate immunity and cellular biology

The interferon-inducible protein with tetrapeptide repeats 3 (IFIT3) is one of the most important members in both the IFIT family and interferon-stimulated genes family. IFIT3 has typical features of the IFIT family in terms of gene and protein structures, and is able to be activated through the classical PRRs-IFN-JAK/STAT pathway. A variety of viruses can induce the expression of IFIT3, which in turn inhibits the replication of viruses, with the underlying mechanism showing its crucial role in antiviral innate immunity. Emerging studies have also identified that IFIT3 is involved in cellular biology changes, including cell proliferation, apoptosis, differentiation, and cancer development. In this review, we summarize the characteristics of IFIT3 with respect to molecular structure and regulatory pathways, highlighting the role of IFIT3 in antiviral innate immunity, as well as its diverse biological roles. We also discuss the potential of IFIT3 as a biomarker in disease diagnosis and therapy.

Potential Molecular Mechanisms and Remdesivir Treatment for Acute Respiratory Syndrome Corona Virus 2 Infection/COVID 19 Through RNA Sequencing and Bioinformatics Analysis

Introduction:

Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) infections (COVID 19) is a progressive viral infection that has been investigated extensively. However, genetic features and molecular pathogenesis underlying remdesivir treatment for SARS-CoV-2 infection remain unclear. Here, we used bioinformatics to investigate the candidate genes associated in the molecular pathogenesis of remdesivir-treated SARS-CoV-2-infected patients.

Methods:

Expression profiling by high-throughput sequencing dataset (GSE149273) was downloaded from the Gene Expression Omnibus, and the differentially expressed genes (DEGs) in remdesivir-treated SARS-CoV-2 infection samples and nontreated SARS-CoV-2 infection samples with an adjusted P value of <.05 and a |log fold change| > 1.3 were first identified by limma in R software package. Next, pathway and gene ontology (GO) enrichment analysis of these DEGs was performed. Then, the hub genes were identified by the NetworkAnalyzer plugin and the other bioinformatics approaches including protein-protein interaction network analysis, module analysis, target gene—miRNA regulatory network, and target gene—TF regulatory network. Finally, a receiver-operating characteristic analysis was performed for diagnostic values associated with hub genes.

Results:

A total of 909 DEGs were identified, including 453 upregulated genes and 457 downregulated genes. As for the pathway and GO enrichment analysis, the upregulated genes were mainly linked with influenza A and defense response, whereas downregulated genes were mainly linked with drug metabolism—cytochrome P450 and reproductive process. In addition, 10 hub genes (VCAM1, IKBKE, STAT1, IL7R, ISG15, E2F1, ZBTB16, TFAP4, ATP6V1B1, and APBB1) were identified. Receiver-operating characteristic analysis showed that hub genes (CIITA, HSPA6, MYD88, SOCS3, TNFRSF10A, ADH1A, CACNA2D2, DUSP9, FMO5, and PDE1A) had good diagnostic values.

Conclusion:

This study provided insights into the molecular mechanism of remdesivir-treated SARS-CoV-2 infection that might be useful in further investigations.

Evolution of proteomics technologies for understanding respiratory syncytial virus pathogenesis

Introduction: Respiratory syncytial virus (RSV) is a major human pathogen associated with long term morbidity. RSV replication occurs primarily in the epithelium, producing a complex cellular response associated with acute inflammation and long-lived changes in pulmonary function and allergic disease. Proteomics approaches provide important insights into post-transcriptional regulatory processes including alterations in cellular complexes regulating the coordinated innate response and epigenome.Areas covered: Peer-reviewed proteomics studies of host responses to RSV infections and proteomics techniques were analyzed. Methodologies identified include 1)." bottom-up" discovery proteomics, 2). Organellar proteomics by LC-gel fractionation; 3). Dynamic changes in protein interaction networks by LC-MS; and 4). selective reaction monitoring MS. We introduce recent developments in single-cell proteomics, top-down mass spectrometry, and photo-cleavable surfactant chemistries that will have impact on understanding how RSV induces extracellular matrix (ECM) composition and airway remodeling.Expert opinion: RSV replication induces global changes in the cellular proteome, dynamic shifts in nuclear proteins, and remodeling of epigenetic regulatory complexes linked to the innate response. Pathways discovered by proteomics technologies have led to deeper mechanistic understanding of the roles of heat shock proteins, redox response, transcriptional elongation complex remodeling and ECM secretion remodeling in host responses to RSV infections and pathological sequelae.

Bioinformatics analyses of significant genes, related pathways, and candidate diagnostic biomarkers and molecular targets in SARS-CoV-2/COVID-19

Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) infection is a leading cause of pneumonia and death. The aim of this investigation is to identify the key genes in SARS-CoV-2 infection and uncover their potential functions. We downloaded the expression profiling by high throughput sequencing of GSE152075 from the Gene Expression Omnibus database. Normalization of the data from primary SARS-CoV-2 infected samples and negative control samples in the database was conducted using R software. Then, joint analysis of the data was performed. Pathway and Gene ontology (GO) enrichment analyses were performed, and the protein-protein interaction (PPI) network, target gene - miRNA regulatory network, target gene - TF regulatory network of the differentially expressed genes (DEGs) were constructed using Cytoscape software. Identification of diagnostic biomarkers was conducted using receiver operating characteristic (ROC) curve analysis. 994 DEGs (496 up regulated and 498 down regulated genes) were identified. Pathway and GO enrichment analysis showed up and down regulated genes mainly enriched in the NOD-like receptor signaling pathway, Ribosome, response to external biotic stimulus and viral transcription in SARS-CoV-2 infection. Down and up regulated genes were selected to establish the PPI network, modules, target gene - miRNA regulatory network, target gene - TF regulatory network revealed that these genes were involved in adaptive immune system, fluid shear stress and atherosclerosis, influenza A and protein processing in endoplasmic reticulum. In total, ten genes (CBL, ISG15, NEDD4, PML, REL, CTNNB1, ERBB2, JUN, RPS8 and STUB1) were identified as good diagnostic biomarkers. In conclusion, the identified DEGs, hub genes and target genes contribute to the understanding of the molecular mechanisms underlying the advancement of SARS-CoV-2 infection and they may be used as diagnostic and molecular targets for the treatment of patients with SARS-CoV-2 infection in the future.

Impact of Respiratory Syncytial Virus Infection on Host Functions: Implications for Antiviral Strategies

Respiratory syncytial virus (RSV) is one of the leading causes of viral respiratory tract infection in infants, the elderly, and the immunocompromised worldwide, causing more deaths each year than influenza. Years of research into RSV since its discovery over 60 yr ago have elucidated detailed mechanisms of the host-pathogen interface. RSV infection elicits widespread transcriptomic and proteomic changes, which both mediate the host innate and adaptive immune responses to infection, and reflect RSV's ability to circumvent the host stress responses, including stress granule formation, endoplasmic reticulum stress, oxidative stress, and programmed cell death. The combination of these events can severely impact on human lungs, resulting in airway remodeling and pathophysiology. The RSV membrane envelope glycoproteins (fusion F and attachment G), matrix (M) and nonstructural (NS) 1 and 2 proteins play key roles in modulating host cell functions to promote the infectious cycle. This review presents a comprehensive overview of how RSV impacts the host response to infection and how detailed knowledge of the mechanisms thereof can inform the development of new approaches to develop RSV vaccines and therapeutics.

Quantitative proteomic analysis of human corneal epithelial cells infected with HSV-1

HSV-1 infection in corneal epithelium initiates the process of herpes simplex keratitis. We investigated the dynamic change of the host proteins in corneal epithelial cells infected with HSV-1 to understand the virus-host interaction. iTRAQ coupled with LC-MS/MS was applied to quantitatively analyze the protein profiles in HSV-1 infected corneal epithelial cells at 6 and 24 h post-infection (hpi), and the results were validated by multiple reaction monitoring (MRM). We also performed bioinformatic analysis to investigate the potentially important signal pathways and protein interaction networks in the host response to HSV-1 infection. We identified 292 proteins were up-regulated and 168 proteins were down-regulated at 6 hpi, while 132 proteins were up-regulated and 89 proteins were down-regulated at 24 hpi, which were validated by MRM analysis. We found the most enriched GO terms were translational initiation, cytosol, poly(A) RNA binding, mRNA splicing via spliceosome and extracellular exosome for the dysregulated proteins. KEGG pathway analysis revealed significant changes in metabolism pathway characterized by decreased tricarboxylic acid cycle activity and increased glycolysis. Proteins interaction network analysis indicated several proteins including P4HB, ACLY, HSP90AA1 and EIF4A3, might be critical proteins in the host-virus response. Our study for the first time analyzed the protein profile of HSV-1 infected primary corneal epithelial cells by quantitative proteomics. These findings help to better understand the host-virus interaction and the pathogenesis of herpes simplex keratitis.

Global quantitative proteomic analysis profiles host protein expression in response to Sendai virus infection

Sendai virus (SeV) is an enveloped nonsegmented negative-strand RNA virus that belongs to the genus Respirovirus of the Paramyxoviridae family. As a model pathogen, SeV has been extensively studied to define the basic biochemical and molecular biologic properties of the paramyxoviruses. In addition, SeV-infected host cells were widely employed to uncover the mechanism of innate immune response. To identify proteins involved in the SeV infection process or the SeV-induced innate immune response process, system-wide evaluations of SeV-host interactions have been performed. cDNA microarray, siRNA screening and phosphoproteomic analysis suggested that multiple signaling pathways are involved in SeV infection process. Here, to study SeV-host interaction, a global quantitative proteomic analysis was performed on SeV-infected HEK 293T cells. A total of 4699 host proteins were quantified, with 742 proteins being differentially regulated. Bioinformatics analysis indicated that regulated proteins were mainly involved in "interferon type I (IFN-I) signaling pathway" and "defense response to virus," suggesting that these processes play roles in SeV infection. Further RNAi-based functional studies indicated that the regulated proteins, tripartite motif (TRIM24) and TRIM27, affect SeV-induced IFN-I production. Our data provided a comprehensive view of host cell response to SeV and identified host proteins involved in the SeV infection process or the SeV-induced innate immune response process.

Systematic Analysis of Cell-Type Differences in the Epithelial Secretome Reveals Insights into the Pathogenesis of Respiratory Syncytial Virus-Induced Lower Respiratory Tract Infections

Lower respiratory tract infections from respiratory syncytial virus (RSV) are due, in part, to secreted signals from lower airway cells that modify the immune response and trigger airway remodeling. To understand this process, we applied an unbiased quantitative proteomics analysis of the RSV-induced epithelial secretory response in cells representative of the trachea versus small airway bronchiolar cells. A workflow was established using telomerase-immortalized human epithelial cells that revealed highly reproducible cell type-specific differences in secreted proteins and nanoparticles (exosomes). Approximately one third of secretome proteins are exosomal; the remainder are from lysosomal and vacuolar compartments. We applied this workflow to three independently derived primary human cultures from trachea versus bronchioles. A total of 577 differentially expressed proteins from control supernatants and 966 differentially expressed proteins from RSV-infected cell supernatants were identified at a 1% false discovery rate. Fifteen proteins unique to RSV-infected primary human cultures from trachea were regulated by epithelial-specific ets homologous factor. A total of 106 proteins unique to RSV-infected human small airway epithelial cells was regulated by the transcription factor NF-κB. In this latter group, we validated the differential expression of CCL20/macrophage-inducible protein 3α, thymic stromal lymphopoietin, and CCL3-like 1 because of their roles in Th2 polarization. CCL20/macrophage-inducible protein 3α was the most active mucin-inducing factor in the RSV-infected human small airway epithelial cell secretome and was differentially expressed in smaller airways in a mouse model of RSV infection. These studies provide insights into the complexity of innate responses and regional differences in the epithelial secretome participating in RSV lower respiratory tract infection-induced airway remodeling.

Exome-wide analysis of rare coding variation identifies novel associations with COPD and airflow limitation in MOCS3, IFIT3 and SERPINA12

Background

Several regions of the genome have shown to be associated with COPD in genome-wide association studies of common variants.

Objective

To determine rare and potentially functional single nucleotide polymorphisms (SNPs) associated with the risk of COPD and severity of airflow limitation.

Methods

3226 current or former smokers of European ancestry with lung function measures indicative of Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2 COPD or worse were genotyped using an exome array. An analysis of risk of COPD was carried out using ever smoking controls (n=4784). Associations with %predicted FEV₁ were tested in cases. We followed-up signals of interest (p<10⁻⁵) in independent samples from a subset of the UK Biobank population and also undertook a more powerful discovery study by meta-analysing the exome array data and UK Biobank data for variants represented on both arrays.

Results

Among the associated variants were two in regions previously unreported for COPD; a low frequency non-synonymous SNP in MOCS3 (rs7269297, p_discovery=3.08×10⁻⁶, p_replication=0.019) and a rare SNP in IFIT3, which emerged in the meta-analysis (rs140549288, p_meta=8.56×10⁻⁶). In the meta-analysis of % predicted FEV₁ in cases, the strongest association was shown for a splice variant in a previously unreported region, SERPINA12 (rs140198372, p_meta=5.72×10⁻⁶). We also confirmed previously reported associations with COPD risk at MMP12, HHIP, GPR126 and CHRNA5. No associations in novel regions reached a stringent exome-wide significance threshold (p<3.7×10⁻⁷).

Conclusions

This study identified several associations with the risk of COPD and severity of airflow limitation, including novel regions MOCS3, IFIT3 and SERPINA12, which warrant further study.

Novel insights into human respiratory syncytial virus-host factor interactions through integrated proteomics and transcriptomics analysis

The lack of vaccine and limited antiviral options against respiratory syncytial virus (RSV) highlights the need for novel therapeutic strategies. One alternative is to develop drugs that target host factors required for viral replication. Several microarray and proteomics studies had been published to identify possible host factors that are affected during RSV replication. In order to obtain a comprehensive understanding of RSV-host interaction, we integrated available proteome and transcriptome datasets and used it to construct a virus-host interaction network. Then, we interrogated the network to identify host factors that are targeted by the virus and we searched for drugs from the DrugBank database that interact with these host factors, which may have potential applications in repositioning for future treatment options of RSV infection.

Hepatitis C virus subverts liver-specific miR-122 to protect the viral genome from exoribonuclease Xrn2

The abundant, liver-specific microRNA miR-122 forms extensive base-pairing interactions with the 5' noncoding region of the hepatitis C virus (HCV) RNA genome, protecting the viral RNA from degradation. We discovered that the 5'-3' exoribonuclease Xrn2, which plays a crucial role in the transcription termination of RNA polymerase II, modulates HCV RNA abundance in the cytoplasm, but is counteracted by miR-122-mediated protection. Specifically, Xrn2 depletion results in increased accumulation of viral RNA, while Xrn2 overexpression diminishes viral RNA abundance. Depletion of Xrn2 did not alter translation or replication rates of HCV RNA, but affected viral RNA stability. Importantly, during sequestration of miR-122, Xrn2 depletion restored HCV RNA abundance, arguing that Xrn2 depletion eliminates the miR-122 requirement for viral RNA stability. Thus, Xrn2 has a cytoplasmic, antiviral function against HCV that is counteracted by HCV's subversion of miR-122 to form a protective oligomeric complex at the 5' end of the viral genome.

A comprehensive proteomic view of responses of A549 type II alveolar epithelial cells to human respiratory syncytial virus infection

Human respiratory syncytial virus is a major respiratory pathogen for which there are no suitable antivirals or vaccines. A better understanding of the host cell response to this virus may redress this problem. The present report concerns analysis of multiple independent biological replicates of control and 24 h infected lysates of A549 cells by two different proteomic workflows. One workflow involved fractionation of lysates by in-solution protein IEF and individual fractions were digested using trypsin prior to capillary HPLC-LTQ-OrbitrapXL-MS/MS. A second workflow involved digestion of whole cell lysates and analysis by nanoUltraHPLC-LTQ-OrbitrapElite-MS/MS. Both workflows resulted in the quantification of viral proteins exclusively in lysates of infected cells in the relative abundances anticipated from previous studies. Unprecedented numbers (3247 - 5010) of host cell protein groups were also quantified and the infection-specific regulation of a large number (191) of these protein groups was evident based on a stringent false discovery rate cut-off (<1%). Bioinformatic analyses revealed that most of the regulated proteins were potentially regulated by type I, II, and III interferon, TNF-α and noncanonical NF-κB2 mediated antiviral response pathways. Regulation of specific protein groups by infection was validated by quantitative Western blotting and the cytokine-/key regulator-specific nature of their regulation was confirmed by comparable analyses of cytokine treated A549 cells. Overall, it is evident that the workflows described herein have produced the most comprehensive proteomic characterization of host cell responses to human respiratory syncytial virus published to date. These workflows will form the basis for analysis of the impacts of specific genes of human respiratory syncytial virus responses of A549 and other cell lines using a gene-deleted version of the virus. They should also prove valuable for the analysis of the impact of other infectious agents on host cells.

Leukocyte transcript alterations in West-African girls following a booster vaccination with diphtheria-tetanus-pertussis vaccine

BACKGROUND

Observational studies from low-income countries have shown that the vaccination against diphtheria, tetanus and pertussis (DTP) is associated with excess female mortality due to infectious diseases.

METHODS

To investigate possible changes in gene expression after DTP vaccination, we identified a group of nine comparable West African girls, from a biobank of 356 children, who were due to receive DTP booster vaccine at age 18 months. As a pilot experiment we extracted RNA from blood samples before, and 6 weeks after, vaccination to analyze the coding transcriptome in leukocytes using expression microarrays, and ended up with information from eight girls. The data was further analyzed using dedicated array pathway and network software. We aimed to study whether DTP vaccination introduced a systematic alteration in the immune system in girls.

RESULTS

We found very few transcripts to alter systematically. Those that did mainly belonged to the Interferon (IFN) signalling pathway. We scrutinized this pathway as well as the Interleukin (IL) pathways. Two out of eight showed a down-regulated IFN pathway and two showed an up-regulated IFN pathway. The two with down-regulated IFN pathway had also down-regulated IL-6 pathway. In the study of networks, two of the girls stood out as not having the inflammatory response as top altered network.

CONCLUSION

The transcriptome changes following DTP booster vaccination were subtle, but although the material was small, it was possible to identify sub groups that deviate from each other, mainly in the IFN response.

Simultaneous quantification of the viral antigens hemagglutinin and neuraminidase in influenza vaccines by LC-MSE

Current methods for quality control of inactivated influenza vaccines prior to regulatory approval include determining the hemagglutinin (HA) content by single radial immunodiffusion (SRID), verifying neuraminidase (NA) enzymatic activity, and demonstrating that the levels of the contaminant protein ovalbumin are below a set threshold of 1 μg/dose. The SRID assays require the availability of strain-specific reference HA antigens and antibodies, the production of which is a potential rate-limiting step in vaccine development and release, particularly during a pandemic. Immune responses induced by neuraminidase also contribute to protection from infection; however, the amounts of NA antigen in influenza vaccines are currently not quantified or standardized. Here, we report a method for vaccine analysis that yields simultaneous quantification of HA and NA levels much more rapidly than conventional HA quantification techniques, while providing additional valuable information on the total protein content. Enzymatically digested vaccine proteins were analyzed by LC-MS(E), a mass spectrometric technology that allows absolute quantification of analytes, including the HA and NA antigens, other structural influenza proteins and chicken egg proteins associated with the manufacturing process. This method has potential application for increasing the accuracy of reference antigen standards and for validating label claims for HA content in formulated vaccines. It can also be used to monitor NA and chicken egg protein content in order to monitor manufacturing consistency. While this is a useful methodology with potential for broad application, we also discuss herein some of the inherent limitations of this approach and the care and caution that must be taken in its use as a tool for absolute protein quantification. The variations in HA, NA and chicken egg protein concentrations in the vaccines analyzed in this study are indicative of the challenges associated with the current manufacturing and quality control testing procedures.