scholarly journals Dengue Nonstructural Protein 1 Maintains Autophagy through Retarding Caspase-Mediated Cleavage of Beclin-1

2020 ◽  
Vol 21 (24) ◽  
pp. 9702
Author(s):  
Zi-Yi Lu ◽  
Miao-Huei Cheng ◽  
Chia-Yi Yu ◽  
Yee-Shin Lin ◽  
Trai-Ming Yeh ◽  
...  
Keyword(s):  
Cell Apoptosis ◽  
Nonstructural Protein ◽  
Antiviral Drug ◽  
Cellular Responses ◽  
Denv Infection ◽  
Beclin 1 ◽  
Protein Inhibition ◽  
Nonstructural Protein 1 ◽  
Significant Public Health ◽  
Related Proteins

Dengue virus (DENV) infection is a significant public health threat in tropical and subtropical regions; however, there is no specific antiviral drug. Accumulated studies have revealed that DENV infection induces several cellular responses, including autophagy and apoptosis. The crosstalk between autophagy and apoptosis is associated with the interactions among components of these two pathways, such as apoptotic caspase-mediated cleavage of autophagy-related proteins. Here, we show that DENV-induced autophagy inhibits early cell apoptosis and hence enhances DENV replication. Later, the apoptotic activities are elevated to suppress autophagy through cleavage of Beclin-1, an essential autophagy-related protein. Inhibition of cleavage of Beclin-1 by a pan-caspase inhibitor, Z-VAD, increases both autophagy and viral replication. Regarding the mechanism, we further found that DENV nonstructural protein 1 (NS1) is able to interact with Beclin-1 during DENV infection. The interaction between Beclin-1 and NS1 attenuates Beclin-1 cleavage and facilitates autophagy to prevent cell apoptosis. Our study suggests a novel mechanism whereby NS1 preserves Beclin-1 for maintaining autophagy to antagonize early cell apoptosis; however, elevated caspases trigger apoptosis by degrading Beclin-1 in the late stage of infection. These findings suggest implications for anti-DENV drug design.

scholarly journals Potential Phosphorylation of Viral Nonstructural Protein 1 in Dengue Virus Infection

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1393
Author(s):  
Thanyaporn Dechtawewat ◽  
Sittiruk Roytrakul ◽  
Yodying Yingchutrakul ◽  
Sawanya Charoenlappanit ◽  
Bunpote Siridechadilok ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Nonstructural Protein ◽  
Antiviral Drug ◽  
Denv Infection ◽  
Site Directed Mutagenesis ◽  
Phosphorylation Sites ◽  
Post Translational Modification ◽  
Multifunctional Protein ◽  
Nonstructural Protein 1 ◽  
Underlying Mechanisms

Dengue virus (DENV) infection causes a spectrum of dengue diseases that have unclear underlying mechanisms. Nonstructural protein 1 (NS1) is a multifunctional protein of DENV that is involved in DENV infection and dengue pathogenesis. This study investigated the potential post-translational modification of DENV NS1 by phosphorylation following DENV infection. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), 24 potential phosphorylation sites were identified in both cell-associated and extracellular NS1 proteins from three different cell lines infected with DENV. Cell-free kinase assays also demonstrated kinase activity in purified preparations of DENV NS1 proteins. Further studies were conducted to determine the roles of specific phosphorylation sites on NS1 proteins by site-directed mutagenesis with alanine substitution. The T27A and Y32A mutations had a deleterious effect on DENV infectivity. The T29A, T230A, and S233A mutations significantly decreased the production of infectious DENV but did not affect relative levels of intracellular DENV NS1 expression or NS1 secretion. Only the T230A mutation led to a significant reduction of detectable DENV NS1 dimers in virus-infected cells; however, none of the mutations interfered with DENV NS1 oligomeric formation. These findings highlight the importance of DENV NS1 phosphorylation that may pave the way for future target-specific antiviral drug design.

scholarly journals Porcine Parvovirus Infection Causes Pig Placenta Tissue Damage Involving Nonstructural Protein 1 (NS1)-Induced Intrinsic ROS/Mitochondria-Mediated Apoptosis

Viruses ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 389 ◽  
Author(s):  
Zhang ◽  
Fan ◽  
Li ◽  
Liang ◽  
Huo ◽  
...  
Keyword(s):  
Host Cell ◽  
Cell Apoptosis ◽  
Nonstructural Protein ◽  
Placental Tissue ◽  
Reproductive Failure ◽  
Porcine Parvovirus ◽  
Nonstructural Protein 1 ◽  
Host Cell Apoptosis ◽  
Tissue Damages ◽  
Induced Apoptosis

Porcine parvovirus (PPV) is an important pathogen causing reproductive failure in pigs. PPV-induced cell apoptosis has been recently identified as being involved in PPV-induced placental tissue damages resulting in reproductive failure. However, the molecular mechanism was not fully elucidated. Here we demonstrate that PPV nonstructural protein 1 (NS1) can induce host cell apoptosis and death, thereby indicating the NS1 may play a crucial role in PPV-induced placental tissue damages and reproductive failure. We have found that NS1-induced apoptosis was significantly inhibited by caspase 9 inhibitor, but not caspase 8 inhibitor, and transfection of NS1 gene into PK-15 cells significantly inhibited mitochondria-associated antiapoptotic molecules Bcl-2 and Mcl-1 expressions and enhanced proapoptotic molecules Bax, P21, and P53 expressions, suggesting that NS1-induced apoptosis is mainly through the mitochondria-mediated intrinsic apoptosis pathway. We also found that both PPV infection and NS1 vector transfection could cause host DNA damage resulting in cell cycle arrest at the G1 and G2 phases, trigger mitochondrial ROS accumulation resulting in mitochondria damage, and therefore, induce the host cell apoptosis. This study provides a molecular basis for elucidating PPV-induced cell apoptosis and reproductive failure.

scholarly journals Lysine 164 is critical for SARS-CoV-2 Nsp1 inhibition of host gene expression

2020 ◽  
Author(s):  
Zhou Shen ◽  
Guangxu Zhang ◽  
Yilin Yang ◽  
Mengxia Li ◽  
Siqi Yang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nonstructural Protein ◽  
Antiviral Drug ◽  
Ribosomal Subunit ◽  
Virus Production ◽  
Host Gene ◽  
Host Protein ◽  
Renilla Luciferase ◽  
Host Gene Expression ◽  
Nonstructural Protein 1

The emerging pathogen severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused social and economic disruption worldwide, infecting over 9.0 million people and killing over 469 000 by 24 June 2020. Unfortunately, no vaccine or antiviral drug that completely eliminates the transmissible disease coronavirus disease 2019 (COVID-19) has been developed to date. Given that coronavirus nonstructural protein 1 (nsp1) is a good target for attenuated vaccines, it is of great significance to explore the detailed characteristics of SARS-CoV-2 nsp1. Here, we first confirmed that SARS-CoV-2 nsp1 had a conserved function similar to that of SARS-CoV nsp1 in inhibiting host-protein synthesis and showed greater inhibition efficiency, as revealed by ribopuromycylation and Renilla luciferase (Rluc) reporter assays. Specifically, bioinformatics and biochemical experiments showed that by interacting with 40S ribosomal subunit, the lysine located at amino acid 164 (K164) was the key residue that enabled SARS-CoV-2 nsp1 to suppress host gene expression. Furthermore, as an inhibitor of host-protein expression, SARS-CoV-2 nsp1 contributed to cell-cycle arrest in G0/G1 phase, which might provide a favourable environment for virus production. Taken together, this research uncovered the detailed mechanism by which SARS-CoV-2 nsp1 K164 inhibited host gene expression, laying the foundation for the development of attenuated vaccines based on nsp1 modification.

Anti-dengue virus nonstructural protein 1 antibodies contribute to platelet phagocytosis by macrophages

2016 ◽  
Vol 115 (03) ◽  
pp. 646-656 ◽  
Author(s):  
Ya-Ting Chu ◽  
Chiou-Feng Lin ◽  
Chih-Peng Chang ◽  
Trai-Ming Yeh ◽  
Robert Anderson ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Platelet Adhesion ◽  
Molecular Mimicry ◽  
Nonstructural Protein ◽  
Denv Infection ◽  
Dengue Disease ◽  
Nonstructural Protein 1 ◽  
Tnf Α ◽  
Β3 Integrin ◽  
Lines Of Evidence

SummaryThrombocytopenia is an important clinical manifestation of dengue disease. The hypotheses concerning the pathogenesis of thrombocytopenia include decreased production and increased destruction or consumption of platelets. We previously suggested a mechanism of molecular mimicry in which antibodies (Abs) directed against dengue virus (DENV) nonstructural protein 1 (NS1) cross-react with platelets. Furthermore, several lines of evidence show activation of endothelial cells (ECs) and macrophages are related to dengue disease severity. Previous studies also suggested that Ab-opsonised platelets facilitate the engulfment of platelets by macrophages. Here we show that TNF-α-activated ECs upregulate adhesion molecule expression to enhance the binding of platelets and macrophages and lead to anti-DENV NS1 Ab-mediated platelet phagocytosis. We further demonstrate that the interaction between macrophages and TNF-α-activated ECs requires binding of FcγR with the Fc region of platelet-bound anti-DENV NS1 Abs. Importantly, the binding of anti-DENV NS1 Abs to platelets did not interfere with platelet adhesion to ECs. The adhesion molecules ICAM-1 and β3 integrin expressed on ECs as well as the FcγR expressed on macrophages were critical in anti-DENV NS1 Ab-mediated platelet phagocytosis on activated ECs. Moreover, anti-DENV NS1 Abs dramatically enhanced platelet engulfment by macrophages in a murine model of DENV infection. Our study provides evidence for a novel role for anti-DENV NS1 Abs in the pathogenesis of thrombocytopenia in dengue disease by enhancing platelet phagocytosis by macrophages.

scholarly journals Endothelial Cell Apoptosis Induced by Antibodies Against Dengue Virus Nonstructural Protein 1 Via Production of Nitric Oxide

2002 ◽  
Vol 169 (4) ◽  
pp. 2215-2215 ◽  
Author(s):  
Chiou-Feng Lin ◽  
Huan-Yao Lei ◽  
Ai-Li Shiau ◽  
Hsiao-Sheng Liu ◽  
Trai-Ming Yeh ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cell ◽  
Dengue Virus ◽  
Cell Apoptosis ◽  
Nonstructural Protein ◽  
Endothelial Cell Apoptosis ◽  
Nonstructural Protein 1

Antibodies against thrombin in dengue patients contain both anti-thrombotic and pro-fibrinolytic activities

2013 ◽  
Vol 110 (08) ◽  
pp. 358-365 ◽  
Author(s):  
Yung-Chun Chuang ◽  
Yee-Shin Lin ◽  
Hsiao-Sheng Liu ◽  
Jen-Reng Wang ◽  
Trai-Ming Yeh
Keyword(s):  
Nonstructural Protein ◽  
Protein A ◽  
Denv Infection ◽  
Functional Studies ◽  
Nonstructural Protein 1 ◽  
Dengue Patient ◽  
Human Thrombin ◽  
Life Threatening ◽  
Human Plasminogen

SummaryDengue virus (DENV) infection may result in severe life-threatening Dengue haemorrhagic fever (DHF). The mechanisms causing haemorrhage in those with DHF are unclear. In this study, we demonstrated that antibodies against human thrombin were increased in the sera of Dengue patients but not in that of patients infected with other viruses. To further characterise the properties of these antibodies, affinity-purified anti-thrombin antibodies (ATAs) were collected from Dengue patient sera by thrombin and protein A/L affinity columns. Most of the ATAs belonged to the IgG class and recognized DENV nonstructural protein 1 (NS1). In addition, we found that dengue patient ATAs also cross-reacted with human plasminogen (Plg). Functional studies in vitro indicated that Dengue patient ATAs could inhibit thrombin activity and enhance Plg activation. Taken together, these results suggest that DENV NS1-induced thrombin and Plg cross-reactive antibodies may contribute to the development of haemorrhage in patients with DHF by interfering with coagulation and fibrinolysis.

scholarly journals Comparable Accuracies of Nonstructural Protein 1- and Envelope Protein-Based Enzyme-Linked Immunosorbent Assays in Detecting Anti-Dengue Immunoglobulin G Antibodies

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 741
Author(s):  
Jedhan Ucat Galula ◽  
Gielenny M. Salem ◽  
Raul V. Destura ◽  
Roland Remenyi ◽  
Day-Yu Chao
Keyword(s):  
Immunoglobulin G ◽  
Nonstructural Protein ◽  
Serological Test ◽  
Denv Infection ◽  
Health Concern ◽  
Natural Immunity ◽  
Global Public Health ◽  
Nonstructural Protein 1 ◽  
Immunosorbent Assays ◽  
Focus Reduction

Background: Dengue virus (DENV) infection remains a global public health concern. Enzyme-linked immunosorbent assays (ELISAs), which detect antibodies targeting the envelope (E) protein of DENV, serve as the front-line serological test for presumptive dengue diagnosis. Very few studies have determined the serostatus by detecting antibodies targeting the nonstructural protein 1 (NS1), which can function as diagnostic biomarkers to distinguish natural immunity from vaccine-induced immunity. Methods: We used community-acquired human serum specimens, with the serostatus confirmed by focus reduction microneutralization test (FRμNT), to evaluate the diagnostic performances of two NS1-based ELISA methods, namely, immunoglobulin G antibody-capture ELISA (NS1 GAC–ELISA) and indirect NS1 IgG ELISA, and compared the results with an E-based virus-like particle (VLP) GAC–ELISA. Results: NS1-based methods had comparable accuracies as VLP GAC–ELISA. Although the sensitivity in detecting anti-NS1 IgM was poor, indirect NS1 IgG ELISA showed similar limits of detection (~1–2 ng/mL) as NS1 GAC–ELISA in detecting anti-NS1 IgG. Combining the results from two or more tests as a composite reference standard can determine the DENV serostatus with a specificity reaching 100%. Conclusion: NS1-based ELISAs have comparable accuracies as VLP GAC–ELISA in determining dengue serostatus, which could effectively assist clinicians during assessments of vaccine eligibility.

scholarly journals Epidemiological survey and screening strategy for dengue virus in blood donors from Yunnan Province

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ling Li ◽  
Ying Li ◽  
Shaofang Lu ◽  
Jing Dong ◽  
Haixia Xu ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Southern China ◽  
Nonstructural Protein ◽  
Denv Infection ◽  
Screening Strategy ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rt Pcr ◽  
Donor Screening ◽  
Blood Center ◽  
Nonstructural Protein 1

Abstract Background Dengue virus (DENV) infection is increasingly common in southern China and can be transmitted through blood transfusion but is not currently part of donor screening throughout the region. We assessed DENV prevalence among donors at the Xishuangbanna Blood Center, Yunnan, to support development of DENV screening strategies. Methods Blood samples were collected randomly between June 2019 and August 2019. These were screened for anti-DENV IgG and IgM using enzyme-linked immunosorbent assay (ELISA). Then, all reactive samples and some randomly-chosen non-reactive samples were used to detect DENV RNAs using real-time polymerase-chain-reaction (RT-PCR) assays. After RT-PCR, samples were further tested for soluble nonstructural protein 1 (NS1) using the colloidal gold method. Donors demographics were also collected and assessed. Results Over the study period, 2254 donor samples were collected and tested for anti-DENV IgG and IgM by ELISA. This revealed 598 anti-DENV IgG and/or IgM reactive samples, a serological prevalence of 26.53%. Of these, 26 were RT-PCR positive and/or NS1 positive. Significant differences in DENV prevalence were noted by occupation (P = 0.001), education (P < 0.001), and ethnicity (P = 0.026). Conclusion The prevalence of DENV in Xishuangbanna Blood Center was higher than most other blood centers that have implemented DENV donor screening. Our study provides first-hand data about the prevalence of DENV and allows the development of a screening strategy for clinical use.

scholarly journals Comprehensive Evaluation of Differential Serodiagnosis between Zika and Dengue Viral Infections

2018 ◽  
Vol 57 (3) ◽  
Author(s):  
Day-Yu Chao ◽  
Matthew T. Whitney ◽  
Brent S. Davis ◽  
Freddy A. Medina ◽  
Jorge L. Munoz ◽  
...  
Keyword(s):  
Nonstructural Protein ◽  
Statistical Significance ◽  
Virus Titer ◽  
Denv Infection ◽  
Immunoglobulin M ◽  
Nucleic Acid Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sample Collection ◽  
Serum Samples ◽  
Nonstructural Protein 1

ABSTRACT Diagnostic testing for Zika virus (ZIKV) or dengue virus (DENV) infection can be accomplished by a nucleic acid detection method; however, a negative result does not exclude infection due to the low virus titer during infection depending on the timing of sample collection. Therefore, a ZIKV- or DENV-specific serological assay is essential for the accurate diagnosis of patients and to mitigate potential severe health outcomes. A retrospective study design with dual approaches of collecting human serum samples for testing was developed. All serum samples were extensively evaluated by using both noninfectious wild-type (wt) virus-like particles (VLPs) and soluble nonstructural protein 1 (NS1) in the standard immunoglobulin M (IgM) antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA). Both ZIKV-derived wt-VLP- and NS1-MAC-ELISAs were found to have similar sensitivities for detecting anti-premembrane/envelope and NS1 antibodies from ZIKV-infected patient sera, although lower cross-reactivity to DENV2/3-NS1 was observed. Furthermore, group cross-reactive (GR)-antibody-ablated homologous fusion peptide-mutated (FP)-VLPs consistently showed higher positive-to-negative values than homologous wt-VLPs. Therefore, we used DENV-2/3 and ZIKV FP-VLPs to develop a novel, serological algorithm for differentiating ZIKV from DENV infection. Overall, the sensitivity and specificity of the FP-VLP-MAC-ELISA and the NS1-MAC-ELISA were each higher than 80%, with no statistical significance. The accuracy can reach up to 95% with the combination of FP-VLP and NS1 assays. In comparison to current guidelines using neutralization tests to measure ZIKV antibody, this approach can facilitate laboratory screening for ZIKV infection, especially in regions where DENV infection is endemic and capacity for neutralization testing does not exist.

scholarly journals Inflammatory signaling in dengue-infected platelets requires translation and secretion of nonstructural protein 1

2020 ◽  
Vol 4 (9) ◽  
pp. 2018-2031 ◽  
Author(s):  
Anna Cecíllia Quirino-Teixeira ◽  
Stephane Vicente Rozini ◽  
Giselle Barbosa-Lima ◽  
Diego Rodrigues Coelho ◽  
Pedro Henrique Carneiro ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Nonstructural Protein ◽  
Platelet Activating Factor ◽  
Denv Infection ◽  
Autocrine Loop ◽  
Extracellular Milieu ◽  
Caspase 1 ◽  
Nonstructural Protein 1 ◽  
Synergistic Activation ◽  
Inflammatory Phenotype

Abstract Emerging evidence identifies major contributions of platelets to inflammatory amplification in dengue, but the mechanisms of infection-driven platelet activation are not completely understood. Dengue virus nonstructural protein-1 (DENV NS1) is a viral protein secreted by infected cells with recognized roles in dengue pathogenesis, but it remains unknown whether NS1 contributes to the inflammatory phenotype of infected platelets. This study shows that recombinant DENV NS1 activated platelets toward an inflammatory phenotype that partially reproduced DENV infection. NS1 stimulation induced translocation of α-granules and release of stored factors, but not of newly synthesized interleukin-1β (IL-1β). Even though both NS1 and DENV were able to induce pro-IL-1β synthesis, only DENV infection triggered caspase-1 activation and IL-1β release by platelets. A more complete thromboinflammatory phenotype was achieved by synergistic activation of NS1 with classic platelet agonists, enhancing α-granule translocation and inducing thromboxane A2 synthesis (thrombin and platelet-activating factor), or activating caspase-1 for IL-1β processing and secretion (adenosine triphosphate). Also, platelet activation by NS1 partially depended on toll-like receptor-4 (TLR-4), but not TLR-2/6. Finally, the platelets sustained viral genome translation and replication, but did not support the release of viral progeny to the extracellular milieu, characterizing an abortive viral infection. Although DENV infection was not productive, translation of the DENV genome led to NS1 expression and release by platelets, contributing to the activation of infected platelets through an autocrine loop. These data reveal distinct, new mechanisms for platelet activation in dengue, involving DENV genome translation and NS1-induced platelet activation via platelet TLR4.

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