Project description:Viral infection often triggers eukaryotic initiator factor 2α (eIF2α) phosphorylation, leading to global 5’-cap-dependent translation inhibition. RSV encodes messenger RNAs (mRNAs) mimicking 5’-cap structures of host mRNAs and thus inhibition of cap-dependent translation initiation would likely also reduce viral translation. We confirmed that RSV limits widespread translation initiation inhibition and unexpectedly found that the fraction of ribosomes within polysomes increases during infection, indicating higher ribosome loading on mRNAs during infection. We found that AU-rich host transcripts that are less efficiently translated under normal conditions become more efficient at recruiting ribosomes, similar to RSV transcripts. Viral transcripts are transcribed in cytoplasmic inclusion bodies, where the viral AU-rich binding protein M2-1 has been shown to bind viral transcripts and shuttle them into the cytoplasm. We further demonstrated that M2-1 is found on polysomes, and that M2-1 might deliver host AU-rich transcripts for translation.
Project description:Respiratory syncytial virus (RSV) is a seasonal respiratory pathogen that primarily affects young children, potentially causing severe lower respiratory tract disease. Despite the high disease burden, understanding of RSV pathophysiology remains limited. To address this, advanced RSV infection models are needed. While HEp-2 cells are widely used due to their high susceptibility to RSV, they do not accurately reflect the host response of the human respiratory tract. In this study, we evaluated human induced pluripotent stem cell-derived respiratory organoids, which contain respiratory epithelial cells, immune cells, fibroblasts, and vascular endothelial cells, for their potential to model RSV infection and support pharmaceutical research. RSV-infected organoids exhibited high viral genome and protein expression, epithelial layer destruction, and increased collagen accumulation. Pro-inflammatory cytokine levels in culture supernatants also increased post-infection. Furthermore, RSV infection was significantly inhibited by monoclonal antibodies (nirsevimab, palivizumab, suptavumab, or clesrovimab), while ribavirin showed limited efficacy. These findings highlight the utility of respiratory organoids for RSV research.
Project description:Respiratory syncytial virus (RSV) is a seasonal respiratory pathogen that primarily affects young children, potentially causing severe lower respiratory tract disease. Despite the high disease burden, understanding of RSV pathophysiology remains limited. To address this, advanced RSV infection models are needed. While HEp-2 cells are widely used due to their high susceptibility to RSV, they do not accurately reflect the host response of the human respiratory tract. In this study, we evaluated human induced pluripotent stem cell-derived respiratory organoids, which contain respiratory epithelial cells, immune cells, fibroblasts, and vascular endothelial cells, for their potential to model RSV infection and support pharmaceutical research. RSV-infected organoids exhibited high viral genome and protein expression, epithelial layer destruction, and increased collagen accumulation. Pro-inflammatory cytokine levels in culture supernatants also increased post-infection. Furthermore, RSV infection was significantly inhibited by monoclonal antibodies (nirsevimab, palivizumab, suptavumab, or clesrovimab), while ribavirin showed limited efficacy. These findings highlight the utility of respiratory organoids for RSV research.
Project description:Respiratory syncytial virus (RSV) is a seasonal respiratory pathogen that primarily affects young children, potentially causing severe lower respiratory tract disease. Despite the high disease burden, understanding of RSV pathophysiology remains limited. To address this, advanced RSV infection models are needed. While HEp-2 cells are widely used due to their high susceptibility to RSV, they do not accurately reflect the host response of the human respiratory tract. In this study, we evaluated human induced pluripotent stem cell-derived respiratory organoids, which contain respiratory epithelial cells, immune cells, fibroblasts, and vascular endothelial cells, for their potential to model RSV infection and support pharmaceutical research. RSV-infected organoids exhibited high viral genome and protein expression, epithelial layer destruction, and increased collagen accumulation. Pro-inflammatory cytokine levels in culture supernatants also increased post-infection. Furthermore, RSV infection was significantly inhibited by monoclonal antibodies (nirsevimab, palivizumab, suptavumab, or clesrovimab), while ribavirin showed limited efficacy. These findings highlight the utility of respiratory organoids for RSV research.
Project description:Human Respiratory Syncytial Virus (hRSV) is a prevalent pathogen posing significant risks to infants and older adults. While the roles of RSV non-structural proteins NS1 protein in modulating host immune responses remains poorly defined, its potential impact on viral pathogenicity is critical. We employed CUT&RUN of NS1, Mediator, and ATF3 in WT NS1 and mutant NS1 expressing A549 cells and bulk RNA sequencing of WT and mutant NS1-expressing A549 (GSE155151) and RSV infection in human lung air-liquid interface (ALI) cultures to elucidate the perterbations of transcriptional regulatory control induced by NS1. Coupled with our earlier work, these epigenomic and transcriptomic profiling datasets provides deeper insights into the molecular mechanisms through which RSV NS1 protein disrupts host immune functions.
Project description:N6-methyladenosine (m6A) is the most abundant internal RNA modification catalyzed by host RNA methyltransferases. As obligate intracellular parasites, many viruses acquire m6A methylation in their RNAs. However, the biological functions of viral m6A methylation are poorly understood. Here, we found that viral m6A methylation serves as a molecular marker for host innate immunity to discriminate self from nonself RNA and that this novel biological function of viral m6A methylation is universally conserved in non-segmented negative-sense (NNS) RNA viruses. Using m6A methyltransferase (METTL3)-knockout cells, we produced m6A-deficient virion RNA from the representative members of the families Pneumoviridae, Paramyxoviridae, and Rhabdoviridae and found that these m6A-deficient viral RNAs triggered significantly higher levels of type I interferon compared to the m6A-sufficient viral RNAs, in a RIG-I dependent manner. Reconstitution of the RIG-I pathway revealed that m6A-deficient virion RNA induced higher expression of RIG-I, bound to RIG-I more efficiently, enhanced RIG-I ubiquitination, and facilitated RIG-I conformational rearrangement and oligomerization. Furthermore, the m6A binding protein YTHDF2 sequesters m6A-sufficient virion RNA which suppresses type I interferon signaling pathway. Collectively, our results suggest that NNS RNA viruses acquire m6A in viral RNA as a common strategy to evade host innate immunity.