Cell penetrable human scFv specific to middle domain of matrix protein-1 protects mice from lethal influenza.
ABSTRACT: A new anti-influenza remedy that can tolerate the virus antigenic variation is needed. Influenza virus matrix protein-1 (M1) is highly conserved and pivotal for the virus replication cycle: virus uncoating, assembly and budding. An agent that blocks the M1 functions should be an effective anti-influenza agent. In this study, human scFv that bound to recombinant M1 middle domain (MD) and native M1 of A/H5N1 was produced. Phage mimotope search and computerized molecular docking revealed that the scFv bound to the MD conformational epitope formed by juxtaposed helices 7 and 9 of the M1. The scFv was linked molecularly to a cell penetrable peptide, penetratin (PEN). The PEN-scFv (transbody), when used to treat the cells pre-infected with the heterologous clade/subclade A/H5N1 reduced the viral mRNA intracellularly and in the cell culture fluids. The transbody mitigated symptom severity and lung histopathology of the H5N1 infected mice and caused reduction of virus antigen in the tissues as well as extricated the animals from the lethal challenge in a dose dependent manner. The transbody specific to the M1 MD, either alone or in combination with the cognate human scFvs specific to other influenza virus proteins, should be an effective, safe and mutation tolerable anti-influenza agent.
Project description:BACKGROUND: Novel effective anti-influenza agent that tolerates influenza virus antigenic variation is needed. Highly conserved influenza virus M2 protein has multiple pivotal functions including ion channel activity for vRNP uncoating, anti-autophagy and virus assembly, morphogenesis and release. Thus, M2 is an attractive target of anti-influenza agents including small molecular drugs and specific antibodies. METHODS: Fully human monoclonal single chain antibodies (HuScFv) specific to recombinant and native M2 proteins of A/H5N1 virus were produced from huscfv-phagemid transformed E. coli clones selected from a HuScFv phage display library using recombinant M2 of clade 1 A/H5N1 as panning antigen. The HuScFv were tested for their ability to inhibit replication of A/H5N1 of both homologous and heterologous clades. M2 domains bound by HuScFv of individual E. coli clones were identified by phage mimotope searching and computerized molecular docking. RESULTS: HuScFv derived from four huscfv-phagemid transformed E. coli clones (no. 2, 19, 23 and 27) showed different amino acid sequences particularly at the CDRs. Cells infected with A/H5N1 influenza viruses (both adamantane sensitive and resistant) that had been exposed to the HuScFv had reduced virus release and intracellular virus. Phage peptide mimotope search and multiple alignments revealed that conformational epitopes of HuScFv2 located at the residues important for ion channel activity, anti-autophagy and M1 binding; epitopic residues of HuScFv19 located at the M2 amphipathic helix and cytoplasmic tail important for anti-autophagy, virus assembly, morphogenesis and release; epitope of HuScFv23 involved residues important for the M2 activities similar to HuScFv2 and also amphipathic helix residues for viral budding and release while HuScFv27 epitope spanned ectodomain, ion channel and anti-autophagy residues. Results of computerized homology modelling and molecular docking conformed to the epitope identification by phages. CONCLUSIONS: HuScFv that bound to highly conserved epitopes across influenza A subtypes and human pathogenic H5N1clades located on different functional domains of M2 were produced. The HuScFv reduced viral release and intracellular virus of infected cells. While the molecular mechanisms of the HuScFv await experimental validation, the small human antibody fragments have high potential for developing further as a safe, novel and mutation tolerable anti-influenza agent especially against drug resistant variants.
Project description:The matrix protein 1 (M1) of influenza A virus (IAV) exists as a three-dimensional oligomeric structure in mature virions with high sequence conservation across different IAV subtypes, which makes it a potential broad spectrum antiviral target. We hypothesized that impairing self-association of M1 through a small molecule 'wedge', which avidly binds to an M1-M1 interface, would result in a completely new class of anti-influenza agents. To establish this proof-of-principle, we performed virtual screening on a library of >70,000 commercially available small molecules that resulted in several plausible 'wedges'. Biophysical studies showed that the best molecule bound the M1 protein potently and weakened M1-M1 self-association. Most importantly, the agent reduced the thickness of the M1 layer in mature virions and inhibited in ovo propagation of multiple IAV strains including H1N1, pandemic H1N1, H3N2 and H5N1, which supports the "wedge" hypothesis. These results demonstrate that M1 is a promising druggable target for the discovery of a completely new line of broad spectrum anti-IAV agents.
Project description:The pathogenesis of avian influenza A H5N1 virus in human has not been clearly elucidated. There have been increasing evidence suggesting a role for virus-induced cytokine dysregulation in contributing to the pathogenesis of human H5N1 disease. However, the role of aberrant innate immune response in human lungs infected by avian influenza H5N1 virus has not been explored and direct evidence for inappropriate innate responses in lungs of avian influenza H5N1 virus infected patients is lacking. Overall design: In order to obtain evidences for the proposed role of aberrant innate immune response in avian influenza H5N1 virus pathogenesis in human, we analyzed expression profile of lung tissues from two fatal cases of avian influenza H5N1 virus infected patients in comparison to normal human lung using an expression microarray.
Project description:The neuraminidase inhibitors oseltamivir and zanamivi are used to treat H5N1 influenza. However, oseltamivir-resistant H5N1 viruses have been isolated from oseltamivir-treated patients. Moreover, reassortment between H5N1 viruses and oseltamvir-resistant human H1N1 viruses currently circulating could create oseltamivir-resistant H5N1 viruses, rendering the oseltamivir stockpile obsolete. Therefore, there is a need for unique and effective antivirals to combat H5N1 influenza viruses. The investigational drug T-705 (favipiravir; 6-fluoro-3-hydroxy-2-pyrazinecarboxamide) has antiviral activity against seasonal influenza viruses and a mouse-adapted H5N1 influenza virus derived from a benign duck virus. However, its efficacy against highly pathogenic H5N1 viruses, which are substantially more virulent, remains unclear. Here, we demonstrate that T-705 effectively protects mice from lethal infection with oseltamivir-sensitive or -resistant highly pathogenic H5N1 viruses. Furthermore, our biochemical analysis suggests that T-705 ribofuranosyl triphosphate, an active form of T-705, acts like purines or purine nucleosides in human cells and does not inhibit human DNA synthesis. We conclude that T-705 shows promise as a therapeutic agent for the treatment of highly pathogenic H5N1 influenza patients.
Project description:BACKGROUND:Avian influenza A H5N1 virus can cause lethal disease in humans. The virus can trigger severe pneumonia and lead to acute respiratory distress syndrome. Data from clinical, in vitro and in vivo suggest that virus-induced cytokine dysregulation could be a contributory factor to the pathogenesis of human H5N1 disease. However, the precise mechanism of H5N1 infection eliciting the unique host response are still not well understood. METHODS:To obtain a better understanding of the molecular events at the earliest time points, we used RNA-Seq to quantify and compare the host mRNA and miRNA transcriptomes induced by the highly pathogenic influenza A H5N1 (A/Vietnam/3212/04) or low virulent H1N1 (A/Hong Kong/54/98) viruses in human monocyte-derived macrophages at 1-, 3-, and 6-h post infection. RESULTS:Our data reveals that two macrophage populations corresponding to M1 (classically activated) and M2 (alternatively activated) macrophage subtypes respond distinctly to H5N1 virus infection when compared to H1N1 virus or mock infection, a distinction that could not be made from previous microarray studies. When this confounding variable is considered in our statistical model, a clear set of dysregulated genes and pathways emerges specifically in H5N1 virus-infected macrophages at 6-h post infection, whilst was not found with H1N1 virus infection. Furthermore, altered expression of genes in these pathways, which have been previously implicated in viral host response, occurs specifically in the M1 subtype. We observe a significant up-regulation of genes in the RIG-I-like receptor signaling pathway. In particular, interferons, and interferon-stimulated genes are broadly affected. The negative regulators of interferon signaling, the suppressors of cytokine signaling, SOCS-1 and SOCS-3, were found to be markedly up-regulated in the initial round of H5N1 virus replication. Elevated levels of these suppressors could lead to the eventual suppression of cellular antiviral genes, contributing to pathophysiology of H5N1 virus infection. CONCLUSIONS:Our study provides important mechanistic insights into the understanding of H5N1 viral pathogenesis and the multi-faceted host immune responses. The dysregulated genes could be potential candidates as therapeutic targets for treating H5N1 disease.
Project description:The importance of influenza viruses as worldwide infectious agents is well recognized. Specific mutations and evolution in influenza viruses is difficult to predict. We studied specific mutations in matrix protein 1 (M1) of H5N1 influenza A virus together with properties associated with it using prediction tools developed in Bioinformatics. Changes in hydrophobicity, polarity and secondary structure at the site of mutation were noticed and documented to gain insight towards its infection.
Project description:Human tracheobronchial epithelial (HTBE) cells are considered to serve as a good correlate of influenza virus infection in the human respiratory tract. ChIP-Seq analysis was used to profile histone acetylation (H3K27ac) in HTBE cells at multiple time points in response to infection with influenza A/California/04/09 (H1N1), A/Wyoming/03/03 (H3N2), and A/Vietnam/1203/04 (H5N1) HALo virus. The Influenza A/Vietnam/1203/04 (H5N1) HALo mutant virus is an attenuated H5N1 virus generated from wild-type Influenza A/Vietnam/1203/04 (H5N1) virus as described in Steel, J., et al. J Virol. 2009 Feb; 83(4):1742-53. Overall design: Human tracheobronchial epithelial cells were infected with H1N1, H3N2, and H5N1 influenza virus at an MOI of 5. H3N2- and H5N1-infected samples were collected in duplicates at 3, 6, 12, and 18 hours post infection for ChIP-Seq analysis. Sample from H1N1-infected cells were collected at 6, 12, 18, and 24 hours. Uninfected controls (mock infection) were also collected at a single time.
Project description:The pathogenesis of avian influenza A H5N1 virus in human has not been clearly elucidated. There have been increasing evidence suggesting a role for virus-induced cytokine dysregulation in contributing to the pathogenesis of human H5N1 disease. However, the role of aberrant innate immune response in human lungs infected by avian influenza H5N1 virus has not been explored and direct evidence for inappropriate innate responses in lungs of avian influenza H5N1 virus infected patients is lacking. In order to obtain evidences for the proposed role of aberrant innate immune response in avian influenza H5N1 virus pathogenesis in human, we analyzed expression profile of lung tissues from two fatal cases of avian influenza H5N1 virus infected patients in comparison to normal human lung using an expression microarray.
Project description:Hi-C was used to profile changes in the genome structure of human primary cells at multiple time points in response to infection with active and UV-inactivated H5N1 influenza virus. Human tracheobronchial epithelial cells (HTBE) and monocyte-derived macrophages (MDM) were used. The Influenza A/Vietnam/1203/04 (H5N1) HALo mutant virus is an attenuated H5N1 virus generated from wild-type Influenza A/Vietnam/1203/04 (H5N1) virus as described in Steel, J., et al. J Virol. 2009 Feb; 83(4):1742-53. Overall design: Human tracheobronchial epithelial cells and monocyte-derived macrophages, obtained from multiple donors, were infected with active and UV-inactivated H5N1 influenza. Samples were collected in duplicate at 6, 12, and 18 hours post-infection for Hi-C analysis, along with time-matched uninfected controls.
Project description:The cellular transcriptome of C57BL/6 mouse lungs was profiled by mRNA-Seq analysis at multiple time points in response to infection with influenza A/California/04/09 (H1N1), A/Wyoming/03/03 (H3N2), and A/Vietnam/1203/04 (H5N1) HALo virus. The Influenza A/Vietnam/1203/04 (H5N1) HALo mutant virus is an attenuated H5N1 virus generated from wild-type Influenza A/Vietnam/1203/04 (H5N1) virus as described in Steel, J., et al. J Virol. 2009 Feb; 83(4):1742-53. A/Wyoming/03/03 (H3N2) influenza virus replicates poorly in mice and lung tissue collected from mice inoculated with this virus did not carry viral loads detectable by plaque assay. Overall design: Six to eight week-old female C57BL/6 mice were infected with influenza A/California/04/09 (H1N1), A/Wyoming/03/03 (H3N2), or A/Vietnam/1203/04 (H5N1) HALo virus. Lungs from 3 infected mice per experimental group were collected at 12h, 1d, 2d, 3d and 4d post infection. Lungs of mice treated with PBS, collected after 4 d, served as mock control.