Fosaprepitant Dimeglumine Alleviates Dengue Virus Infection and Virus-Induced Inflammatory Responses.

Dengue virus (DV) is a mosquito-borne flavivirus that causes hemorrhagic fever in humans. In the natural infection, DV is introduced into human skin by an infected mosquito vector where it is believed to target immature dendritic cells (DCs) and Langerhans cells (LCs). We found that DV productively infects DCs but not LCs. We show here that the interactions between DV E protein, the sole mannosylated glycoprotein present on DV particles, and the C-type lectin dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) are essential for DV infection of DCs. Binding of mannosylated N-glycans on DV E protein to DC-SIGN triggers a rapid and efficient internalization of the viral glycoprotein. However, we observed that endocytosis-defective DC-SIGN molecules allow efficient DV replication, indicating that DC-SIGN endocytosis is dispensable for the internalization step in DV entry. Together, these results argue in favor of a mechanism by which DC-SIGN enhances DV entry and infection in cis. We propose that DC-SIGN concentrates mosquito-derived DV particles at the cell surface to allow efficient interaction with an as yet unidentified entry factor that is ultimately responsible for DV internalization and pH-dependent fusion into DCs.

Dengue virus (DENV) infection causes dengue fever, dengue hemorrhagic fever, or dengue shock syndrome. Interferons (IFNs), and IFN-γ dependent chemokines, chemokine (C-X-C motif) ligand (CXCL)10/IFN-γ-induced protein 10 (IP-10), CXCL9/MIG and CXCL11/I-TAC, and their common receptor chemokine (C-X-C motif) receptor (CXCR)3 are induced by DENV infection; however it has been shown that the latter two could not compensate for the absence of IP-10. This paper reviews studies about DENV and IP-10. Evidences show the importance of IP-10 induction during DENV infection, in macrophages, lymphocytes, hepatic cells, denritic cells, in skin and in the brain. Furthermore it has been shown that chemokines IP-10, I-TAC and their receptor CXCR3 are involved in severity of dengue; in fact, pulmonary effusion or ascites, painful hepatomegaly or aspartate aminotransferase increase, are correlated with IP-10 levels. It has been also demonstrated that IP-10 was more elevated in subjects who subsequently developed dengue hemorrhagic fever or dengue shock syndrome. It has been also shown that IP-10 has a direct action in control of dengue viral replication. Furthermore IP-10 circulating levels may be used to discriminate dengue fever from other febbrile diseases. This is of particular importance in certain situations, for example to discriminate occupationally acquired dengue, in patients with febbrile disorders coming from endemic countries. These studies suggested that these chemokines can be used as potential biomarkers for differential diagnosis and the disease progression, while others can be used to control dengue viral replication, thus representing a viable targets for drug therapy.

Clinical symptoms of Dengue vary from mild febrile illness to severe infection. A potent pro-inflammatory cytokine, IL-17, secreted by mainly Th17 cells mediate inflammation and autoimmune diseases. Role of IL-17 in pathogenesis of dengue virus (DV) infection is not clear. Total 211 dengue patients and 70 healthy controls were enrolled. IL-17 level was tested in serum samples from all cases and controls. Cases were grouped as either dengue or severe dengue; based on WHO (2009) classification. Anti DV IgG antibody detection and DV serotype specific PCR were also done. Levels of IL-17 in dengue and severe dengue patients, primary and secondary DV infection were compared. Association of DV serotypes with severity of illness and various clinical and laboratory features with IL-17 levels were analyzed. Of total 211cases, 90 and 121cases were presenting as dengue and severe dengue illness, respectively. Levels of IL-17 were significantly higher in dengue patients as compared to control. Mean level of IL-17 was higher in severe cases than non severe cases; however difference was not statistically significant. Stratified analysis of IL-17 level in different age group showed significantly high IL-17 levels in children with severe dengue. Mean level of IL-17 was also significantly higher in cases with secondary DV infection in comparison to primary DV infection. Levels of IL-17 were higher in patients with DV-2 infection in comparison to cases with DV-1 and DV-3 infection. Significant positive association of high IL-17 levels was seen with pleural effusion and respiratory distress. IL-17 appears to be associated with severe DV infection. It is very important to understand the exact role of IL-17 in the pathogenesis of severe DV infection.

Serine protease inhibitor AEBSF reduces dengue virus infection via decreased cholesterol synthesis

The immune response to viral infection involves a complexity of both innate and adaptive pathways at the cellular and the molecular level. There are many approaches to begin to define the pathways at work to control viral pathogenesis. The approach favored in this thesis was to conduct a broad screen of the innate immune response at the gene expression level of infected cells. The innate immune response is critical to the control of viral infections. Type I interferons (IFN), IFNα and IFNβ, are antiviral proteins that are an integral part of the innate immune response. Furthermore, by virtue of their effects on maturation and activation of antigen-presenting cells, IFNs are a pivotal link between the innate and adaptive immune systems. Most cell types produce type-I IFN when exposed to viruses. However, viruses have evolved multiple strategies to suppress IFN production or signaling. It is imperative to understand the virus-host interaction at the molecular level in order to identify as yet unknown mechanisms of the host antiviral response; these additional pathways may be useful in counteracting the viral suppression of IFN. Type-I IFNs regulate expression of at least five hundred genes, suggesting a complex network of signaling pathways. Depending on the cell type different proteins regulate the induction of IFN or the expression of IFN-inducible genes. Identification of proteins that induce selected IFN-inducible genes may provide synergistic activity with or may have an advantage over type-I IFN for anti-viral therapy in the future. Many diseases are untreatable if identified late in their progression. In resource-limited countries, many diseases are diagnosed clinically, which can lead to incorrect or delayed diagnosis and treatment. The identification of biomarkers of disease has the potential to guide the correct therapy in a timely fashion. The objective of this thesis was to identify novel anti-viral therapies and disease biomarkers for dengue virus (DENV) infection. DENV is a mosquito-borne positive-sense single-stranded RNA virus, which causes an estimated 50 million infections annually. Most DENV infections result in a febrile illness called Dengue fever (DF). Less frequently, infections cause Dengue hemorrhagic fever (DHF), a potentially fatal vascular leakage syndrome associated with the production of pro-inflammatory cytokines. At present patients infected with DENV can only be treated by intravenous fluid support to prevent hypovolemia and hypotensive shock. This treatment is less effective in severe cases if the diagnosis is delayed. Identification of therapeutics with both antiviral and immune-modulatory activity may lower patient mortality and reduce the burden of DENV on society. DENV infection is cleared in most individuals after a short period of viremia {Libraty, 20022225}. Based on in vitro and mouse models, type-I and type-II IFN signaling pathways are thought to be critical in the regulation of DENV infection. Higher serum levels of type I and type II IFNs…

Dengue Virus Infections are distributed in tropical and sub-tropical regions and transmitted by the mosquitoes such as Aedes aegypti and Aedes albopictus. Dengue virus can cause dengue fever, dengue hemorrhagic fever and dengue shock syndrome or dengue and severe dengue classified by World Health Organization. Beside it concurrent infection virus salmonella had been found some cases who showed fever more than 7 days. Concurrent infection with two agents can result in an illness having overlapping symptoms creating a diagnostic dilemma for treating physician, such as dengue fever with typhoid fever. The aim of this research is detection of dengue virus and secondary infection with Salmonella typhi in patients suspected dengue virus infection. Detection of dengue virus and Salmonella typhi using immunochromatography test such as NS1, IgG/IgM for dengue virus infection, and IgM/IgG Salmonella and blood culture. The fifty children with dengue virus infection came to Soerya hospital and 17 cases suspected dengue virus infection, five cases showed a positive NS1 on the second day of fever and one case concurrent with clinical manifestation of convulsi on the third days of fever there were five cases only showed positive. It was showed in this study that on the fourth to six day of fever in dengue virus infection accompanied by antibody IgM & IgG dengue. There were 12 cases showed the clinical manifestation of concurrent dengue viral infection and Salmonella, all of them showed a mild clinical manifestation and did not show plasma leakage and shock. In this study we found the length of stay of concurrent Dengue Virus Infection and Salmonella infection is more than 10 days. These patients were also more likely to have co-existing haemodynamic disturbances and bacterial septicaemia which would have required treatment with inotropes and antibiotics. This idea is very important to make update dengue viral management to decrease mortality in outbreak try to gain new prevention method before the occurrence of outbreak.

Dengue virus (DENV) infection causes dengue fever, dengue haemorrhagic fever, or dengue shock syndrome. Mast cells have been speculated to play a role in DENV disease although their precise roles are unclear. In this study, we used mast cell-deficient Kit(W-sh/W-sh) mice to investigate the involvement of mast cells after intradermal DENV infection. An approximately two- to three-fold higher level of DENV NS3 antigen was detected at the skin inoculation site in DENV-infected Kit(W-sh/W-sh) mice than in DENV-infected wild-type (WT) mice (using a dose of 1 × 10(9) plaque-forming units/mouse). Moreover, as an indicator of heightened pathogenesis, a more prolonged bleeding time was observed in DENV-infected Kit(W-sh/W-sh) mice than in WT mice. Monocytes/macrophages are considered to be important targets for DENV infection, so we investigated the susceptibility and chemokine response of DENV-infected peritoneal macrophages from Kit(W-sh/W-sh) and WT mice both ex vivo and in vivo. There was a tendency for higher DENV infection and higher secretion of CCL2 (MCP-1) from peritoneal macrophages isolated from Kit(W-sh/W-sh) mice than those from WT mice. In vivo studies using intradermal inoculation of DENV showed about twofold higher levels of infiltrating macrophages and CCL2 (MCP-1) at the inoculation site in both mock control and DENV-inoculated Kit(W-sh/W-sh) mice than in corresponding WT mice. In summary, compared with WT mice, Kit(W-sh/W-sh) mice show enhanced DENV infection and macrophage infiltration at the skin inoculation site as well as increased DENV-associated bleeding time. The results indicate an intriguing interplay between mast cells and tissue macrophages to restrict DENV replication in the skin.

Dengue virus (DENV) is a mosquito-borne virus that causes a spectrum of human diseases ranging from mild dengue fever to dengue haemorrhagic fever and dengue shock syndrome in severe cases. Currently, there is no effective antiviral therapy or vaccine against DENV infection. In order to identify potential antiviral agents against DENV, we performed high-throughput cell-based screening on a highly purified natural products library. Among the screening hits, selected compounds which displayed 50-75% inhibition against DENV2 were validated using secondary assays. Time-of-addition studies, dose-dependent assays, real time quantitative reverse transcriptase (RT)-PCR, Western blot and ultrastructural imaging were conducted in an attempt to elucidate the potential antiviral mechanisms of narasin. In this study, an ionophore, narasin was selected for detailed analysis due to its strong inhibitory profile against DENV infection with minimal cytotoxicity (50% cytotoxic concentration >1,000 μM). A dose-dependent study revealed narasin to have an 50% inhibitory concentration of less than 1 μM against all four serotypes of DENV. Time-of-addition studies of narasin-treated, DENV2-infected Huh-7 cells suggested narasin to be involved in inhibiting the post-entry stages of viral replication during DENV infection. Proteomic and ultrastructural analyses revealed the antiviral mechanism of narasin as likely to be associated with the disruption of viral protein synthesis. In addition, quantitative RT-PCR studies showed no differences in viral RNA levels between narasin-treated and control DENV2-infected cells. Narasin was identified and characterized as a novel agent that inhibits DENV replication in vitro through non-cytotoxic mechanisms, thus indicating its potential to be further developed as a therapeutic anti-DENV agent.

Flaviviruses include the most prevalent and medically challenging viruses. Persistent infection with flaviviruses of epithelial cells and hepatocytes that do not undergo cell death is common. Here, we report that, in epithelial cells, up-regulation of autophagy following flavivirus infection markedly enhances virus replication and that one flavivirus gene, NS4A, uniquely determines the up-regulation of autophagy. Dengue-2 and Modoc (a murine flavivirus) kill primary murine macrophages but protect epithelial cells and fibroblasts against death provoked by several insults. The flavivirus-induced protection derives from the up-regulation of autophagy, as up-regulation of autophagy by starvation or inactivation of mammalian target of rapamycin also protects the cells against insult, whereas inhibition of autophagy via inactivation of PI3K nullifies the protection conferred by flavivirus. Inhibition of autophagy also limits replication of both Dengue-2 and Modoc virus in epithelial cells. Expression of flavivirus NS4A is sufficient to induce PI3K-dependent autophagy and to protect cells against death; expression of other viral genes, including NS2A and NS4B, fails to protect cells against several stressors. Flavivirus NS4A protein induces autophagy in epithelial cells and thus protects them from death during infection. As autophagy is vital to flavivirus replication in these cells, NS4A is therefore also identified as a critical determinant of flavivirus replication.

Inhibition of dengue virus replication in monocyte-derived dendritic cells by vivo-morpholino oligomers

Development of an antibody-dependent enhancement assay for dengue virus using stable BHK-21 cell lines expressing FcγRIIA

Early Diagnosis and Early Management Proposal in Dengue Infection: New Normal to Applied Strategy for COVID-19 Infection

Dengue virus (DENV) infection is still a global health problem. The severity of DENV infection is related to the high viral load and cytokine storm caused by excessive inflammation. There is no specific antiviral used for DENV. Meanwhile, the use of anti-inflammatory drugs for DENV is limited to patients with severe clinical symptoms. Interestingly, favipiravir (FVP) and quinine sulfate (QS) have been reported as repurposing drugs that can inhibit DENV replication. However, their anti-inflammatory activity in DENV infection has not been studied yet. Thus, the current study aimed to evaluate both antiviral and inflammatory activities of FVP and QS in Vero and PBMC cells. The FVP and QS antiviral activities were analyzed through half-maximal inhibitory concentration (IC50) and half-maximal cytotoxicity concentration (CC50) values against DENV serotype-1 on Vero cells. The anti-inflammatory activities of FVP and QS were measured by the relative expression of TNF-α, IL-6, IL-10 cytokines, and the transcription factor NF-κB from DENV-1 infected peripheral blood mononuclear cells (PBMC) in vitro. The results showed that the IC50, CC50, and selectivity index (SI) for FVP were 2.72 μg/mL, 156.78 μg/mL, and 58, respectively. Meanwhile, the IC50, CC50, and SI of QS were 14.97 μg/mL, 85.2 μg/mL, and 5.69. Also, FVP and QS reduced the expression of IL-6 and IL-10 but induced the expression of TNF-α, and the transcription factor NF-κB in PBMC with the presence of antibody-dependent enhancement (ADE). Further, FVP has better DENV-1 antiviral activities compared to QS. However, in comparison with QS, FVP showed lower anti-inflammatory activities. Further studies are needed to explore the antiviral and anti-inflammatory mechanism of FVP and QS in the DENV-infected models.

Cepharanthine inhibits dengue virus production and cytokine secretion

Dengue virus (DENV) infection causes dengue fever in humans, which can lead to thrombocytopenia showing a marked reduction in platelet counts, and dengue hemorrhagic fever. The virus may cause thrombocytopenia either by destroying the platelets or by interfering with their generation via the process of megakaryopoiesis. MEG-01 is the human megakaryoblastic leukemia cell line that can be differentiated in vitro by phorbol-12-myristate-13-acetate (PMA) treatment to produce platelet-like-particles (PLPs). We have studied DENV infection of MEG-01 cells to understand its effect on megakaryopoiesis and the generation of PLPs. We observed that DENV could infect only naive MEG-01 cells, and differentiated cells were refractory to virus infection/replication. However, DENV-infected MEG-01 cells, when induced for differentiation with PMA, supported an enhanced viral replication. Following the virus infection, the MEG-01 cells showed a marked reduction in the surface expression of platelet markers (CD41, CD42a, and CD61), a decreased polyploidy, and significantly reduced PLP counts. DENV infection caused an enhanced Notch signaling in MEG-01 cells where the virus envelope protein was shown to interact with TAL-1, a host protein important for megakaryopoiesis. These observations provide new insight into the role of DENV in modulating the megakaryopoiesis and platelet production process.