Dengue virus (DV), a pathogen of global mosquito-borne infectious disease, causes both mild dengue fever and severe dengue hemorrhagic fever (DHF). Generally, the production of pro-inflammatory mediator such as inducible nitric oxide synthase (iNOS)/NO as well as anti-inflammatory cytokine interleukin (IL)-10/suppressor of cytokine signaling (SOCS) 3 is abnormally altered in patients with DHF. In addition to serving as the potential biomarkers for DHF, these two factors are speculated to be antiviral and pathogenic, respectively, for DV infection regarding their crosstalk with interferon (IFN)-γ, a potent antiviral IFN. Furthermore, leukopenia is generally present in hemorrhagic patients with DV infection. Mononuclear phagocytes are the major target cells of DV infection while they are also the major producers of iNOS/NO and IL-10/SOCS3. Notably, the intrinsic antibody-dependent enhancement (ADE) infection of DV can cause higher IL-10/SOCS3 response; however, the molecular mechanisms underlying IL-10 regulation and its immunopathological effects are still unclear. Our previous works (NSC 96-2320-B-006-013, 96-2320-B-006-018 MY3, and 99-2320-B-006-004 MY3) and others have demonstrated that GSK-3 acts as a pro-inflammatory regulator by activating NF-κB/iNOS and by inactivating CREB/IL-10 axis signaling pathways. Altering GSK-3 causes IFN-γ resistance and controls cell survival. We therefore hypothesize that the multifunctional enzyme glycogen synthase kinase (GSK)-3, a key regulator of pro- and anti-inflammation and cell fate determination, plays a potential role for immunopathogenesis in DV infection. For this project, our preliminary results demonstrate that DV infection alone induces IL-10/SOCS3 expression through a mechanism involving protein kinase A- and phosphoinositide 3-kinase/Akt-regulated GSK-3 inactivation followed by CREB activation. This study will be mainly focused on the regulation of GSK-3 for the immune and cellular responses in DV-infected mononuclear phagocytes. In Specific Aim 1, the potential role of GSK-3 signaling will be investigated for the effects of ADE on DV infection-induced iNOS/NO and IL-10/SOCS3 responses, IFN-γ resistance, and the changes on cell fate. In mononuclear phagocytes with ADE of DV infection, the signaling pathways for GSK-3 regulation will be examined and, by using pharmacological and genetic approaches, the potential roles of GSK-3 and GSK-3-regulated its downstream factors for immune and cellular responses will be determined. In Specific Aim 2, the biological roles of immune and cellular responses for DV infection and replication will be clarified. Based on the results of Specific Aim 1, the contribution of iNOS/NO, IL-10/SOCS3, IFN-γ resistance, cell survival, and the regulation of GSK-3 on DV infection and replication will be investigated. In Specific Aim 3, the host cell receptors and viral proteins involved in GSK-3-regulated immune and cellular responses during DV infection will be identified. Several well-known receptors required for DV infection will be examined for their contribution on GSK-3 regulation as well as the immune and cellular responses. By transfection-based overexpression, viral proteins including three structural proteins (capsid protein C, membrane protein M, and envelope protein E) and seven nonstructural proteins (NS1, NS2a, NS2b, NS3, NS4a, NS4b, and NS5) will be investigated for their roles on such effects. The molecular basis of host-pathogen interaction will also be studied. Based on the results obtained from this project, we will clarify the potential role of GSK-3 and GSK-3-regulated immune and cellular responses in DV infection, and will provide potent information for anti-DV infection.
|Effective start/end date||8/1/15 → 7/31/16|
- Mononuclear phagocyte