Project description:Mouse mammary tumor virus (MMTV) is a complex retrovirus that induces breast cancer in mice in the absence of known virally-encoded oncogenes. Like other non-acute retroviruses, tumorigenesis by MMTV is thought to occur primarily through insertional mutagenesis, leading to the activation of cellular proto-oncogenes and outgrowth of selected cells. In this study, we investigated whether MMTV encodes microRNAs (miRNAs) and/or modulates host miRNAs that could contribute to tumorigenesis. We have applied high throughput small RNA sequencing to the analysis of MMTV-infected cells and MMTV-induced mammary tumors. Our results demonstrate that MMTV does not encode miRNAs. However, MMTV infected cells and MMTV-producing tumors have altered levels of several cellular miRNAs, including increases in the expression of members of the oncogenic miRNA cluster, miR-17-92. Notably, similar changes in levels of these miRNAs have been previously reported in human breast cancers. Combined, our results demonstrate that virally encoded miRNAs do not contribute to MMTV-mediated tumorigenesis, but that changes in specific host miRNAs in infected cells may contribute to virus replication and tumor biology.
Project description:Virus proliferation inside host cells relies on a diverse range of host machineries and is also restricted by the host through antiviral factors. The configuration of virus-dependency and antiviral factors determine the permissiveness of host cells to virus infection, however, overall differences between highly permissive and restrictive cellular states remain largely unexplored. Here we employed integrated omics analysis combining RNA-seq, proteomics, and phosphoproteomics to study determinants of virus permissiveness on a model system comprising multiple cellular states: highly permissive cells (HEK293T), steady-state cells (HEK293), and restrictive cells (interferon alpha (IFN-a) stimulated HEK293) due to their similar genetic background and distinct permissiveness. Our in-depth proteomics map across cellular states revealed pathway-level depletion of innate immune response and enrichment of anabolic processes in HEK293T cell. RNA-seq and proteomics results depicted dynamic regulations of IFN-α response across early/late timepoints, highlighting a group of robustly upregulated antiviral factors. In addition, phosphoproteomics uncovered extensive alterations of phosphorylation in IFN-a response. Integrated analysis of multi-level omics results identified putative regulators of infection, and we experimentally validated their roles in virus infection.
Project description:Influenza virus transmission between mothers and nursing-infants has not been investigated although mothers and infants often develop severe disease. Ferrets are considered the most appropriate model for influenza studies. We investigated influenza transmission in infant and nursing-mother ferrets. Influenza infected infants transmitted virus to mother mammary glands leading to live virus excretion in milk and influenza virus positive mammary gland epithelial cells. Global gene expression analysis showed down-regulation of milk production and induction of breast involution and oncogenesis pathways. Our results provide insight into influenza transmission between mothers and infants which may impact fields of infectious disease, maternal/infant health and neoplasm etiology. Total RNA was obtained from nursing mother ferret mammary glands at days 3/4 and 6/7 post-intranasal kit infection with 10^5 EID50 A/California/07/2009 (H1N1). Total RNA was also collected from uninfected control nursing mother mammary gland tissues (n = 3). Changes in gene expression relative to uninfected tissue controls were then investigated.