Recent Insights Into the Molecular Mechanism of Toll-Like Receptor Response to Dengue Virus Infection

Dengue is the most prevalent and rapidly spreading mosquito-borne viral disease caused by dengue virus (DENV). Recently, DENV has been affecting humans within an expanding geographic range due to the warming of the earth. Innate immune responses play a significant role in antiviral defense, and Toll-like receptors (TLRs) are key regulators of innate immunity. Therefore, a detailed understanding of TLR and DENV interactions is important for devising therapeutic and preventive strategies. Several studies have indicated the ability of DENV to modulate the TLR signaling pathway and host immune response. Vaccination is considered one of the most successful medical interventions for preventing viral infections. However, only a partially protective dengue vaccine, the first licensed dengue vaccine CYD-TDV, is available in some dengue-endemic countries to protect against DENV infection. Therefore, the development of a fully protective, durable, and safe DENV vaccine is a priority for global health. Here, we demonstrate the progress made in our understanding of the host response to DENV infection, with a particular focus on TLR response and how DENV avoids the response toward establishing infection. We also discuss dengue vaccine candidates in late-stage development and the issues that must be overcome to enable their success.

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Transcriptional response of Wolbachia-transinfected Aedes aegypti mosquito cells to dengue virus at early stages of infection

Journal of General Virology ◽

10.1099/jgv.0.001694 ◽

2022 ◽

Vol 103 (1) ◽

Author(s):

Michael Leitner ◽

Kayvan Etebari ◽

Sassan Asgari

Keyword(s):

Aedes Aegypti ◽

Dengue Virus ◽

Viral Infections ◽

Transcriptional Response ◽

Denv Infection ◽

Content Type ◽

Public Health Burden ◽

Immune Genes ◽

Link Type ◽

Early Stages

Mosquito-borne flaviviruses are responsible for viral infections and represent a considerable public health burden. Aedes aegypti is the principal vector of dengue virus (DENV), therefore understanding the intrinsic virus–host interactions is vital, particularly in the presence of the endosymbiont Wolbachia, which blocks virus replication in mosquitoes. Here, we examined the transcriptional response of Wolbachia -transinfected Ae. aegypti Aag2 cells to DENV infection. We identified differentially expressed immune genes that play a key role in the activation of anti-viral defence such as the Toll and immune deficiency pathways. Further, genes encoding cytosine and N6-adenosine methyltransferases and SUMOylation, involved in post-transcriptional modifications, an antioxidant enzyme, and heat-shock response were up-regulated at the early stages of DENV infection and are reported here for the first time. Additionally, several long non-coding RNAs were among the differentially regulated genes. Our results provide insight into Wolbachia -transinfected Ae. aegypti’s initial virus recognition and transcriptional response to DENV infection.

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Complexity of Neutralizing Antibodies against Multiple Dengue Virus Serotypes after Heterotypic Immunization and Secondary Infection Revealed by In-Depth Analysis of Cross-Reactive Antibodies

Journal of Virology ◽

10.1128/jvi.00273-15 ◽

2015 ◽

Vol 89 (14) ◽

pp. 7348-7362 ◽

Cited By ~ 42

Author(s):

Wen-Yang Tsai ◽

Anna Durbin ◽

Jih-Jin Tsai ◽

Szu-Chia Hsieh ◽

Stephen Whitehead ◽

...

Keyword(s):

Dengue Virus ◽

Neutralizing Antibodies ◽

Secondary Infection ◽

Denv Infection ◽

Primary Immunization ◽

Dengue Vaccine ◽

Alternative Strategies ◽

Live Attenuated Vaccines ◽

Human Sera ◽

Arboviral Diseases

ABSTRACTThe four serotypes of dengue virus (DENV) cause the most important and rapidly emerging arboviral diseases in humans. The recent phase 2b and 3 studies of a tetravalent dengue vaccine reported a moderate efficacy despite the presence of neutralizing antibodies, highlighting the need for a better understanding of neutralizing antibodies in polyclonal human sera. Certain type-specific (TS) antibodies were recently discovered to account for the monotypic neutralizing activity and protection after primary DENV infection. The nature of neutralizing antibodies after secondary DENV infection remains largely unknown. In this study, we examined sera from 10 vaccinees with well-documented exposure to first and second DENV serotypes through heterotypic immunization with live-attenuated vaccines. Higher serum IgG avidities to both exposed and nonexposed serotypes were found after secondary immunization than after primary immunization. Using a two-step depletion protocol to remove different anti-envelope antibodies, including group-reactive (GR) and complex-reactive (CR) antibodies separately, we found GR and CR antibodies together contributed to more than 50% of neutralizing activities against multiple serotypes after secondary immunization. Similar findings were demonstrated in patients after secondary infection. Anti-envelope antibodies recognizing previously exposed serotypes consisted of a large proportion of GR antibodies, CR antibodies, and a small proportion of TS antibodies, whereas those recognizing nonexposed serotypes consisted of GR and CR antibodies. These findings have implications for sequential heterotypic immunization or primary immunization of DENV-primed individuals as alternative strategies for DENV vaccination. The complexity of neutralizing antibodies after secondary infection provides new insights into the difficulty of their application as surrogates of protection.IMPORTANCEThe four serotypes of dengue virus (DENV) are the leading cause of arboviral diseases in humans. Despite the presence of neutralizing antibodies, a moderate efficacy was recently reported in phase 2b and 3 trials of a dengue vaccine; a better understanding of neutralizing antibodies in polyclonal human sera is urgently needed. We studied vaccinees who received heterotypic immunization of live-attenuated vaccines, as they were known to have received the first and second DENV serotype exposures. We found anti-envelope antibodies consist of group-reactive (GR), complex-reactive (CR), and type-specific (TS) antibodies, and that both GR and CR antibodies contribute significantly to multitypic neutralizing activities after secondary DENV immunization. These findings have implications for alternative strategies for DENV vaccination. Certain TS antibodies were recently discovered to contribute to the monotypic neutralizing activity and protection after primary DENV infection; our findings of the complexity of neutralizing activities after secondary immunization/infection provide new insights for neutralizing antibodies as surrogates of protection.

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An agent-based model of dengue virus transmission shows how multiple uncertainties about vaccine efficacy influence public health impact projections

10.1101/082396 ◽

2016 ◽

Cited By ~ 1

Author(s):

T. Alex Perkins ◽

Robert C. Reiner ◽

Guido España ◽

Quirine A. ten Bosch ◽

Amit Verma ◽

...

Keyword(s):

Public Health ◽

Dengue Virus ◽

Vaccine Efficacy ◽

Denv Infection ◽

Health Impact ◽

Public Health Impact ◽

Statistical Uncertainty ◽

Dengue Vaccine ◽

Agent Based ◽

Biological Uncertainty

ABSTRACTGiven the limited effectiveness of strategies based solely on vector control to reduce dengue virus (DENV) transmission, it is expected that an effective vaccine could play a pivotal role in reducing the global disease burden of dengue. Of several dengue vaccines under development, Dengvaxia® from Sanofi Pasteur recently became the first to become licensed in select countries and to achieve WHO recommendation for use in certain settings, despite the fact that a number of uncertainties about its profile complicate projections of its public health impact. We used a stochastic, agent-based model for DENV transmission to perform simulations of the public health impact of dengue vaccines in light of two key uncertainties: (1) “statistical uncertainty” about the numerical value of the vaccine’s efficacy against disease, and (2) “biological uncertainty” about the extent to which its efficacy against disease derives from the amelioration of symptoms, blocking of DENV infection, or some combination thereof. Simulations of a generic dengue vaccine showed that the proportion of disease episodes averted following 20 years of routine vaccination of nine-year olds at 80% coverage was sensitive to both the numerical value of vaccine efficacy and to the extent to which efficacy derives from blocking of DENV infection. Simulations of a vaccine resembling Dengvaxia® took into account that vaccine trial results substantially reduced statistical uncertainty but did not address biological uncertainty, resulting in the proportion of disease episodes averted being more sensitive to biological uncertainty than to statistical uncertainty. Taken together, our results indicate limitations associated with the use of symptomatic disease as the primary endpoint of dengue vaccine trials and highlight the importance of considering multiple forms of uncertainty in projections of a vaccine’s public health impact.

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Gene Expression Signatures in AML-12 Hepatocyte Cells upon Dengue virus Infection and Acetaminophen Treatment

Viruses ◽

10.3390/v12111284 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1284

Author(s):

Jorge G. G. Ferreira ◽

Sandra G. Gava ◽

Eneida S. Oliveira ◽

Izabella C. A. Batista ◽

Gabriel da R. Fernandes ◽

...

Keyword(s):

Gene Expression ◽

Dengue Virus ◽

Denv Infection ◽

Viral Disease ◽

Biological Processes ◽

Dengue Virus Infection ◽

Liver Disorders ◽

Two Factors ◽

Hepatocyte Cells

Dengue is an acute viral disease caused by Dengue virus (DENV) and is considered to be the most common arbovirus worldwide. The clinical characteristics of dengue may vary from asymptomatic to severe complications and severe organ impairment, particularly affecting the liver. Dengue treatment is palliative with acetaminophen (APAP), usually known as Paracetamol, being the most used drug aiming to relieve the mild symptoms of dengue. APAP is a safe and effective drug but, like dengue, can trigger the development of liver disorders. Given this scenario, it is necessary to investigate the effects of combining these two factors on hepatocyte homeostasis. Therefore, this study aimed to evaluate the molecular changes in hepatocytes resulting from the association between DENV infection and treatment with sub-toxic APAP concentrations. Using an in vitro experimental model of DENV-2 infected hepatocytes (AML-12 cells) treated with APAP, we evaluated the influence of the virus and drug association on the transcriptome of these hepatocytes by RNA sequencing (RNAseq). The virus–drug association was able to induce changes in the gene expression profile of AML-12 cells and here we highlight and explore these changes and its putative influence on biological processes for cellular homeostasis.

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Improvement of the Dengue Virus (DENV) Nonhuman Primate Model via a Reverse Translational Approach Based on Dengue Vaccine Clinical Efficacy Data against DENV-2 and -4

Journal of Virology ◽

10.1128/jvi.00440-18 ◽

2018 ◽

Vol 92 (12) ◽

pp. e00440-18 ◽

Cited By ~ 8

Author(s):

Veronique Barban ◽

Nathalie Mantel ◽

Aymeric De Montfort ◽

Anke Pagnon ◽

Fabrine Pradezynski ◽

...

Keyword(s):

Dengue Virus ◽

Clinical Efficacy ◽

Nonhuman Primate ◽

Vaccine Efficacy ◽

Protective Efficacy ◽

Denv Infection ◽

Dengue Vaccine ◽

Nonhuman Primate Model ◽

Primate Model ◽

Translational Approach

ABSTRACTRecent data obtained with the live-attenuated tetravalent dengue CYD-TDV vaccine showed higher protective efficacy against dengue virus type 4 (DENV-4) than against DENV-2. In contrast, results from previous studies in nonhuman primates predicted comparable high levels of protection against each serotype. Maximum viral loads achieved in macaques by subcutaneous inoculation of DENV are generally much lower than those observed in naturally dengue virus-infected humans. This may contribute to an overestimation of vaccine efficacy. Using more-stringent DENV infection conditions consisting of the intravenous inoculation of 10750% cell culture infectious doses (CCID50) in CYD-TDV-vaccinated macaques, complete protection (i.e., undetectable viral RNA) was achieved in all 6 monkeys challenged with DENV-4 and in 6/18 of those challenged with DENV-2, including transiently positive animals. All other infected macaques (12/18) developed sustained DENV-2 RNAemia (defined as detection of viral RNA in serum samples) although 1 to 3 log10units below the levels achieved in control animals. Similar results were obtained with macaques immunized with either CYD-TDV or monovalent (MV) CYD-2. This suggests that partial protection against DENV-2 was mediated mainly by CYD-2 and not by the other CYDs. Postchallenge induction of strong anamnestic responses, suggesting efficient vaccine priming, likely contributed to the reduction of DENV-2 RNAemia. Finally, an inverse correlation between DENV RNA titers postchallenge and vaccine-induced homotypic neutralizing antibody titers prechallenge was found, emphasizing the key role of these antibodies in controlling DENV infection. Collectively, these data show better agreement with reported data on CYD-TDV clinical vaccine efficacy against DENV-2 and DENV-4. Despite inherent limitations of the nonhuman primate model, these results reinforce its value in assessing the efficacy of dengue vaccines.IMPORTANCEThe nonhuman primate (NHP) model is the most widely recognized tool for assessing the protective activity of dengue vaccine candidates, based on the prevention of postinfection DENV viremia. However, its use has been questioned after the recent CYD vaccine phase III trials, in which moderate protective efficacy against DENV-2 was reported, despite full protection against DENV-2 viremia previously being demonstrated in CYD-vaccinated monkeys. Using a reverse translational approach, we show here that the NHP model can be improved to achieve DENV-2 protection levels that show better agreement with clinical efficacy. With this new model, we demonstrate that the injection of the CYD-2 component of the vaccine, in either a monovalent or a tetravalent formulation, is able to reduce DENV-2 viremia in all immunized animals, and we provide clear statistical evidence that DENV-2-neutralizing antibodies are able to reduce viremia in a dose-dependent manner.

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Sialic Acid Expression in the MosquitoAedes aegyptiand Its Possible Role in Dengue Virus-Vector Interactions

BioMed Research International ◽

10.1155/2015/504187 ◽

2015 ◽

Vol 2015 ◽

pp. 1-16 ◽

Cited By ~ 11

Author(s):

Jorge Cime-Castillo ◽

Philippe Delannoy ◽

Guillermo Mendoza-Hernández ◽

Verónica Monroy-Martínez ◽

Anne Harduin-Lepers ◽

...

Keyword(s):

Sialic Acid ◽

Aedes Aegypti ◽

Dengue Virus ◽

Mammalian Cells ◽

Vector Competence ◽

Denv Infection ◽

Viral Disease ◽

Salivary Gland Extract ◽

Denv Serotypes ◽

Mosquito Saliva

Dengue fever (DF) is the most prevalent arthropod-borne viral disease which affects humans. DF is caused by the four dengue virus (DENV) serotypes, which are transmitted to the host by the mosquitoAedes aegyptithat has key roles in DENV infection, replication, and viral transmission (vector competence). Mosquito saliva also plays an important role during DENV transmission. In this study, we detected the presence of sialic acid (Sia) inAedes aegyptitissues, which may have an important role during DENV-vector competence. We also identified genome sequences encoding enzymes involved in Sia pathways. The cDNA forAedes aegyptiCMP-Sia synthase (CSAS) was amplified, cloned, and functionally evaluated via the complementation of LEC29.Lec32 CSAS-deficient CHO cells.AedesCSAS-transfected LEC29.Lec32 cells were able to express Sia moieties on the cell surface. Sequences related toα-2,6-sialyltransferase were detected in theAedes aegyptigenome. Likewise, we identified Sia-α-2,6-DENV interactions in different mosquito tissues. In addition, we evaluated the possible role of sialylated molecules in a salivary gland extract during DENV internalization in mammalian cells. The knowledge of early DENV-host interactions could facilitate a better understanding of viral tropism and pathogenesis to allow the development of new strategies for controlling DENV transmission.

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The Seroprevalence of Dengue Virus Infection and Its Association With Iron (Fe) Level in Pregnant Women in Guangzhou, China

Frontiers in Medicine ◽

10.3389/fmed.2021.759728 ◽

2021 ◽

Vol 8 ◽

Author(s):

Jiong Wang ◽

Jiufeng Sun ◽

Limei Sun ◽

Yufeng Ye ◽

Hanwei Chen ◽

...

Keyword(s):

Dengue Virus ◽

Pregnant Women ◽

Inductively Coupled Plasma ◽

Denv Infection ◽

Viral Disease ◽

Urine Samples ◽

Enzyme Linked Immunosorbent Assay ◽

Air Conditioner ◽

Serum Samples ◽

Igg Antibody

Dengue fever is regarded as the most prevalent mosquito-borne viral disease in humans. However, information of dengue virus (DENV) infection in pregnant women and the influence factors remain unclear. In this study, we extracted information of 2,076 pregnant women from the Prenatal Environment and Offspring Health (PEOH) birth cohort conducted since 2016 in Guangzhou, China. Peripheral blood and clean midstream urine samples of participants were collected during their hospitalization for childbirth. Indirect enzyme-linked immunosorbent assay (ELISA) was used to detect immunoglobulin G (IgG) antibodies of DENV in serum samples, and inductively coupled plasma mass spectrometry (ICP-MS) was applied to determine the Fe concentrations in the urine samples, which were then adjusted for by urine creatinine and transformed by natural logarithm (ln-Fe). The seroprevalence of DENV IgG antibody in all included participants was 2.22% (46/2,076). We observed higher seroprevalence of IgG antibody in women aged ≥35 years (2.9%), education ≤ 12 years (2.5%), yearly income per capita <100,000 yuan (2.4%), no use of air-conditioner (2.4%), no use of mosquito coils (2.3%), and no exercise during pregnancy (4.1%). A U-shaped relationship was found between ln-Fe concentration and the risk of positive IgG antibody. Compared with women with ln-Fe concentration of 2.0–2.9 μg/g creatinine, slightly higher risks of positive IgG antibody were found among women with ≤2.0 (RR = 4.16, 95% CI: 0.78, 19.91), 3.0–3.9 (RR = 1.93, 95% CI: 0.65, 7.08), 4.0–4.9 (RR = 2.19, 95% CI: 0.65, 8.51), and ≥5.0 μg/g creatinine of ln-Fe (RR = 2.42, 95% CI: 0.46, 11.33). Our findings suggested that the seroprevalence of dengue IgG antibody in pregnant women was comparable to the general population in Guangzhou, China. The risk of DENV infection may be associated with maternal demographic characteristics and behaviors. Both maternal low and high Fe concentrations may be positively associated with the risk of DENV infection.

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Dengue virus type 2 replication is limited by activation of NOD2 and its interactions with RIP2 and MAVS adaptors in THP-1 macrophage-like cells

10.22541/au.161883666.69158067/v1 ◽

2021 ◽

Author(s):

Diana Domínguez-Martínez ◽

Daniel Nuñez Avellaneda ◽

Juan Castillo Cruz ◽

Gloria León-Avila ◽

BLANCA GARCIA-PEREZ ◽

...

Keyword(s):

Dengue Virus ◽

Viral Infections ◽

Denv Infection ◽

Human Macrophage ◽

Infection Period ◽

Viral Loads ◽

Protein Levels ◽

Mock Control

The nucleotide-binding domain (NBD) and leucine-rich repeat receptors, such as NOD-like receptors (NLRs), have pivotal functions in the innate immune response to various viral infections participating during the recognition of pathogens and activation of signaling pathways. One NLR, NOD2, is a dynamic protein that is activated in the presence of viral genomes and metabolites. However, its participation in combating a dengue virus (DENV) infection remains unclear. The aim of this study was to determine the role of NOD2 in macrophage-like THP-1 cells during an in vitro infection with DENV type 2 (DENV2). The interactions of NOD2 with RIP2 and MAVS was examined in DENV2-infected and agonist-stimulated cells. The effects of downregulating NOD2 expression or signaling on virus loads was also evaluated. The cellular mRNA expression and protein levels of NOD2 on cells under the stimuli were quantified with RT-PCR, Western blot and indirect immunofluorescence. Both the mRNA and protein expression of NOD2 was enhanced in response to DENV-2 infection. Interactions of NOD2 with RIP2 and MAVS, analyzed with confocal microscopy and co-immunoprecipitation assays, were time-dependent and increased in the post-infection period, between 6 and 24 h. After silencing NOD2 expression, DENV2-infected cells displayed greater viral loads and decreased expression of IL-8 and IFN-α (measured in supernatants obtained from the cells), compared to the uninfected (mock control) cells or those transfected with irrelevant-siRNA. Thus, in response to a DENV2 infection, NOD2 was activated in THP-1 human macrophage-like cells, the production of IL-8 and IFN-α was enhanced, and viral replication was limited.

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A Label-Free Impedimetric Genosensor for the Nucleic Acid Amplification-Free Detection of Extracted RNA of Dengue Virus

Sensors ◽

10.3390/s20133728 ◽

2020 ◽

Vol 20 (13) ◽

pp. 3728

Author(s):

Ching-Chou Wu ◽

Hao-Yu Yen ◽

Lu-Ting Lai ◽

Guey-Chuen Perng ◽

Cheng-Rei Lee ◽

...

Keyword(s):

Nucleic Acid ◽

Dengue Virus ◽

Electrochemical Impedance ◽

Denv Infection ◽

Viral Disease ◽

Diagnostic Methods ◽

Nucleic Acid Amplification ◽

Great Promise ◽

Label Free ◽

Hybridization Efficiency

Developing rapid and sensitive diagnostic methods for dengue virus (DENV) infection is of prime priority because DENV infection is the most prevalent mosquito-borne viral disease. This work proposes an electrochemical impedance spectroscopy (EIS)-based genosensor for the label-free and nucleic acid amplification-free detection of extracted DENV RNA intended for a sensitive diagnosis of DENV infection. A concentration ratio of 0.04 mM 6-mercaptohexanoic acid (MHA) to 1 mM 6-mercapto-1-hexanol (MCH) was selected to modify thin-film gold electrodes as a link to control the coverage of self-designed probe DNA (pDNA) at a density of 4.5 ± 0.4 × 1011 pDNA/cm2. The pDNA/MHA/MCH-modified genosensors are proven to improve the hybridization efficiency of a synthetic 160-mer target DNA (160mtDNA) with a 140-mer electrode side overhang as compared to other MHA/MCH ratio-modified genosensors. The MHA(0.04 mM)/MCH(1 mM)-modified genosensors also present good hybridization efficiency with the extracted DENV serotype 1 (DENV1) RNA samples, having the same electrode side overhangs with the 160mtDNA, showing a low detection limit of 20 plaque forming units (PFU)/mL, a linear range of 102–105 PFU/mL and good selectivity for DENV1. The pDNA density-controlled method has great promise to construct sensitive genosensors based on the hybridization of extracted DENV nucleic acids.

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Berberine Inhibits Dengue Virus through Dual Mechanisms

Molecules ◽

10.3390/molecules26185501 ◽

2021 ◽

Vol 26 (18) ◽

pp. 5501

Author(s):

Thippayawan Ratanakomol ◽

Sittiruk Roytrakul ◽

Nitwara Wikan ◽

Duncan R. Smith

Keyword(s):

Dengue Virus ◽

Viral Infections ◽

Denv Infection ◽

Nonstructural Proteins ◽

Viral Production ◽

Dual Effect ◽

Traditional Medicines ◽

Cellular Effects ◽

Viral Egress ◽

Tropical Areas

Mosquito transmitted viruses, particularly those of the genus Flavivirus, are a significant healthcare burden worldwide, especially in tropical and sub-tropical areas. However, effective medicines for these viral infections remains lacking. Berberine (BBR) is an alkaloid found in some plants used in traditional medicines in Southeast Asia and elsewhere, and BBR has been shown to possess anti-viral activities. During a screen for potential application to mosquito transmitted viruses, BBR was shown to have virucidal activity against dengue virus (DENV; IC50 42.87 µM) as well as against Zika virus (IC50 11.42 µM) and chikungunya virus (IC50 14.21 µM). BBR was shown to have cellular effects that lead to an increase in cellular DENV E protein without a concomitant effect on DENV nonstructural proteins, suggesting an effect on viral particle formation or egress. While BBR was shown to have an effect of ERK1/2 activation this did not result in defects in viral egress mechanisms. The primary effect of BBR on viral production was likely to be through BBR acting through AMPK activation and disruption of lipid metabolism. Combined these results suggest that BBR has a dual effect on DENV infection, and BBR may have the potential for development as an anti-DENV antiviral.

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