Infections with filoviruses Ebola (EBOV) and Marburg (MARV), lead to the "immune paralysis" characterized by a deficient T cell response and lymphopenia, despite the lack of infection of T cells, and a severe hemorrhagic fever with up to 80% mortality. Over the past decade, researchers identified multiple mechanisms of type I interferon (IFN-I) antagonism mediated by filovirus proteins. However, the mechanisms of the rapid and deleterious disabling of the adaptive immune response by filoviruses remain unknown. Dendritic cells (DC), which are the professional antigen-presenting cells, are believed to be readily infected, but do not undergo normal maturation. Our preliminary data have demonstrated the strong connection between IFN-I antagonism caused by EBOV and the lack of DC maturation. The central hypothesis of the proposal is that the unusually strong and redundant antagonism of the IFN-I response mediated by filovirus proteins and by multiple mechanisms, blocks maturation of DC, resulting in the deficient and/or aberrant stimulation of T cells. The hypothesis will be tested by pursuing three specific aims: 1) Determine the role of IFN-antagonizing domains and IFN-I signaling in the maturation of DC and in the activation, proliferation and apoptosis of T cells;2) Determine the role of soluble factors secreted by the infected DC and specific inhibitory and pro-apoptotic molecules in the activation, proliferation and apoptosis of T cells;3) Determine whether the suppression of T cell activation and proliferation or T cell apoptosis during filovirus infection can be reversed by induction of DC maturation. The project will involve the infection of DC derived from donor blood with a recombinant EBOV, its mutants with the IFN-I antagonizing domains disabled, or MARV;stimulation of primary human CD4+ and CD8+ T cells;characterization of the effects of filovirus infection and IFN-antagonizing domains on transcriptomes of infected DC and stimulated T cells by deep sequencing;blockade of IFN-I signaling and immuno-suppressive and pro-apoptotic pathways;and attempts to rescue maturation of infected DC with cytokine cocktails. Together, these experiments represent a broad, integrated approach to investigate the mechanisms of disabling the adaptive immune response by filoviruses.
Filoviruses cause outbreaks of severe hemorrhagic fever in humans with no approved vaccines or methods of treatment. The proposed research is relevant for public health and NIH's mission because it is aimed at the investigation of fundamental mechanisms of the unusually rapid disabling of the adaptive immune system by the virus in order to reduce the burdens of human disease caused by the virus.
|Johnson, Britney; Li, Jing; Adhikari, Jagat et al. (2016) Dimerization Controls Marburg Virus VP24-dependent Modulation of Host Antioxidative Stress Responses. J Mol Biol 428:3483-94|
|Leung, Daisy W; Amarasinghe, Gaya K (2016) When your cap matters: structural insights into self vs non-self recognition of 5' RNA by immunomodulatory host proteins. Curr Opin Struct Biol 36:133-41|
|Satterfield, Benjamin A; Cross, Robert W; Fenton, Karla A et al. (2016) Nipah Virus C and W Proteins Contribute to Respiratory Disease in Ferrets. J Virol 90:6326-43|
|Yen, Benjamin C; Basler, Christopher F (2016) Effects of Filovirus Interferon Antagonists on Responses of Human Monocyte-Derived Dendritic Cells to RNA Virus Infection. J Virol 90:5108-18|
|Rivera, Andrea; Messaoudi, Ilhem (2016) Molecular mechanisms of Ebola pathogenesis. J Leukoc Biol 100:889-904|
|Bharaj, Preeti; Wang, Yao E; Dawes, Brian E et al. (2016) The Matrix Protein of Nipah Virus Targets the E3-Ubiquitin Ligase TRIM6 to Inhibit the IKKÎµ Kinase-Mediated Type-I IFN Antiviral Response. PLoS Pathog 12:e1005880|
|Edwards, Megan R; Liu, Gai; Mire, Chad E et al. (2016) Differential Regulation of Interferon Responses by Ebola and Marburg Virus VP35 Proteins. Cell Rep 14:1632-40|
|Rialdi, Alex; Campisi, Laura; Zhao, Nan et al. (2016) Topoisomerase 1 inhibition suppresses inflammatory genes and protects from death by inflammation. Science 352:aad7993|
|Chatterjee, Srirupa; Basler, Christopher F; Amarasinghe, Gaya K et al. (2016) Molecular Mechanisms of Innate Immune Inhibition by Non-Segmented Negative-Sense RNA Viruses. J Mol Biol 428:3467-82|
|Ciancanelli, Michael J; Huang, Sarah X L; Luthra, Priya et al. (2015) Infectious disease. Life-threatening influenza and impaired interferon amplification in human IRF7 deficiency. Science 348:448-53|
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