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Virology Jun 2024Therapies targeting virus-host interactions are seen as promising strategies for treating gallid alphaherpesvirus 1 (ILTV) infection. Our study revealed a biphasic...
Therapies targeting virus-host interactions are seen as promising strategies for treating gallid alphaherpesvirus 1 (ILTV) infection. Our study revealed a biphasic activation of two MAPK cascade pathways, MEK/ERK and p38 MAPK, as a notably activated host molecular event in response to ILTV infection. It exhibits antiviral functions at different stages of infection. Initially, the MEK/ERK pathway is activated upon viral invasion, leading to a broad suppression of metabolic pathways crucial for ILTV replication, thereby inhibiting viral replication from the early stage of ILTV infection. As the viral replication progresses, the p38 MAPK pathway activates its downstream transcription factor, STAT1, further hindering viral replication. Interestingly, ILTV overcomes this biphasic antiviral barrier by hijacking host p38-AKT axis, which protects infected cells from the apoptosis induced by infection and establishes an intracellular equilibrium conducive to extensive ILTV replication. These insights could provide potential therapeutic targets for ILTV infection.
PubMed: 38943781
DOI: 10.1016/j.virol.2024.110159 -
International Journal of Biological... Jun 2024Diseases caused by viruses pose a significant risk to the health of aquatic animals, for which there are presently no efficacious remedies. Interferon (IFN) serving as...
Diseases caused by viruses pose a significant risk to the health of aquatic animals, for which there are presently no efficacious remedies. Interferon (IFN) serving as an antiviral agent, is frequently employed in clinical settings. Due to the unique living conditions of aquatic animals, traditional injection of interferon is cumbersome, time-consuming and labor-intensive. This study aimed to prepare IFN microcapsules through emulsion technique by using resistant starch (RS) and carboxymethyl chitosan (CMCS). Optimization was achieved using the Box-Behnken design (BBD) response surface technique, followed by the creation of microcapsules through emulsification. With RS at a concentration of 1.27 %, a water‑oxygen ratio of 3.3:7.4, CaCl at 13.67 %, CMCS at 1.04 %, the rate of encapsulation can escalate to 80.92 %. Rainbow trout infected with Infectious hematopoietic necrosis virus (IHNV) and common carp infected with Spring vireemia (SVCV) exhibited a relative survival rate (RPS) of 65 % and 60 % after treated with IFN microcapsules, respectively. Moreover, the microcapsules effectively reduced the serum AST levels and enhanced the expression of IFNα, IRF3, ISG15, MX1, PKR and Viperin in IHNV-infected rainbow trout and SVCV-infected carp. In conclusion, this integrated IFN microcapsule showed potential as an antiviral agent for treatment of viral diseases in aquaculture.
PubMed: 38942671
DOI: 10.1016/j.ijbiomac.2024.132872 -
Life Sciences Jun 2024The study evaluated the antiviral effect of Verapamil against respiratory syncytial virus (RSV) and investigated its underlying mechanism.
AIMS
The study evaluated the antiviral effect of Verapamil against respiratory syncytial virus (RSV) and investigated its underlying mechanism.
MATERIALS AND METHODS
RSV-infected BALB/c mice were treated with Verapamil. Body weight, survival rates, viral load, lung damage, inflammatory factors, and the expression of RSV fusion (F) protein were analyzed. In cellular studies, intracellular Ca and viral titers were measured in the presence of Verapamil, Calcium Chloride, and EGTA. A time-of-addition assay assessed the antiviral effect of Verapamil.
KEY FINDINGS
Mice infected with RSV and treated with Verapamil exhibited a significant decrease in weight loss, an increase in survival rates, and reductions in viral titers, RSV F protein expression, inflammatory responses, and lung tissue injury. Verapamil reduced intracellular calcium levels, which correlated with reduced viral titers. The addition of calcium chloride reversed the anti-viral effects mediated by Verapamil, while EGTA potentiated them. The antiviral activity of Verapamil was observed during the early phase of RSV infection, likely by blocking Ca channels and inhibiting virus replication.
SIGNIFICANCE
Verapamil effectively inhibits RSV infection by blocking calcium channels and reducing intracellular calcium levels, thereby impeding viral replication. Thus, Verapamil shows promise as a treatment for RSV.
PubMed: 38942358
DOI: 10.1016/j.lfs.2024.122877 -
Journal of Infection and Chemotherapy :... Jun 2024Drug resistance is an important factor in the fight against influenza A virus (IAV). Natural products offer a rich source of lead compounds for the discovery of novel...
BACKGROUND
Drug resistance is an important factor in the fight against influenza A virus (IAV). Natural products offer a rich source of lead compounds for the discovery of novel antiviral drugs. In a previous study, we isolated the sorbicillinoid polyketide HSL-2 from the mycelium of fungus Trichoderma sp. T-4-1. Here, we show that this compound exerts strong antiviral activity against a panel of IAVs.
METHODS
The immunofluorescence and qRT-PCR assays were used to detect the inhibitory effect of HSL-2 toward the replication of influenza virus and IAV-induced expression of the pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β.
RESULTS
The results indicated that HSL-2 inhibited influenza virus replication, and it significantly inhibited IAV-induced overexpression of the pro-inflammatory cytokines TNF-α, IL-6, and IL-1β through modulating the PPAR-γ/NF-κB pathway. Notably, this effect was decreased when cells were transfected with PPAR-γ siRNA or treated with the PPAR-γ inhibitor T0070907. In addition, HSL-2 was able to attenuate lung inflammatory responses and to improve lung lesions in a mouse model of IAV infection.
CONCLUSIONS
In this paper, we identified a microbial secondary metabolite, HSL-2, with anti-influenza virus activity. This report is the first to describe the antiviral activity and mechanism of action of HSL-2, and it provides a new strategy for the development of novel anti-influenza virus drugs from natural sources.
PubMed: 38942291
DOI: 10.1016/j.jiac.2024.06.013 -
Fish & Shellfish Immunology Jun 2024RLR helicases RIG-I and MDA5, which are known as pattern recognition receptors to sense cytoplasmic viral RNAs and trigger antiviral immune responses, are DExD/H-box...
RLR helicases RIG-I and MDA5, which are known as pattern recognition receptors to sense cytoplasmic viral RNAs and trigger antiviral immune responses, are DExD/H-box helicases. In teleost, whether and how non-RLR helicases regulate RLR helicases to affect viral infection remains unclear. Here, we report that the non-RLR helicase DHX40 from grass carp (namely gcDHX40) is a negative regulator of grass carp reovirus (GCRV) infection and RLR-mediated type I IFN production. GcDHX40 was a cytoplasmic protein. Ectopic expression of gcDHX40 facilitated GCRV replication and suppressed type I IFN production induced by GCRV infection and by those genes involved the RLR antiviral signaling pathway. Mechanistically, gcDHX40 promoted the generation of viral inclusion bodies (VIBs) by interacting with the NS38 protein of GCRV. Additionally, gcDHX40 interacted with RLR helicase, and impaired the formation of RLR-MAVS functional complexes. Taken together, our results indicate that gcDHX40 is a novel important proviral host factor involving in promoting the generation of GCRV VIBs and inhibiting the production of RLR-mediated type I IFNs.
PubMed: 38942250
DOI: 10.1016/j.fsi.2024.109730 -
ELife Jun 2024SARS-CoV-2 induces delayed type-I/III interferon production, allowing it to escape the early innate immune response. The delay has been attributed to a deficiency in...
SARS-CoV-2 induces delayed type-I/III interferon production, allowing it to escape the early innate immune response. The delay has been attributed to a deficiency in the ability of cells to sense viral replication upon infection, which in turn hampers activation of the antiviral state in bystander cells. Here, we introduce a cellular automaton model to investigate the spatiotemporal spreading of viral infection as a function of virus and host-dependent parameters. The model suggests that the considerable person-to-person heterogeneity in SARS-CoV-2 infections is a consequence of high sensitivity to slight variations in biological parameters near a critical threshold. It further suggests that within-host viral proliferation can be curtailed by the presence of remarkably few cells that are primed for IFN production. Thus, the observed heterogeneity in defense readiness of cells reflects a remarkably cost-efficient strategy for protection.
Topics: SARS-CoV-2; Humans; COVID-19; Virus Replication; Immunity, Innate; Epithelial Cells; Interferons
PubMed: 38941138
DOI: 10.7554/eLife.94056 -
MBio Jun 2024Autophagy is an important biological process in host defense against viral infection. However, many viruses have evolved various strategies to disrupt the host antiviral...
UNLABELLED
Autophagy is an important biological process in host defense against viral infection. However, many viruses have evolved various strategies to disrupt the host antiviral system. Porcine reproductive and respiratory syndrome virus (PRRSV) is a typical immunosuppressive virus with a large economic impact on the swine industry. At present, studies on the escape mechanism of PRRSV in the autophagy process, especially through chaperone-mediated autophagy (CMA), are limited. This study confirmed that PRRSV glycoprotein 5 (GP5) could disrupt the formation of the GFAP-LAMP2A complex by inhibiting the MTORC2/PHLPP1/GFAP pathway, promoting the dissociation of the pGFAP-EF1α complex, and blocking the K63-linked polyubiquitination of LAMP2A to inhibit the activity of CMA. Further research demonstrated that CMA plays an anti-PRRSV role by antagonizing nonstructural protein 11 (NSP11)-mediated inhibition of type I interferon (IFN-I) signaling. Taken together, these results indicate that PRRSV GP5 inhibits the antiviral effect of CMA by targeting LAMP2A. This research provides new insight into the escape mechanism of immunosuppressive viruses in CMA.
IMPORTANCE
Viruses have evolved sophisticated mechanisms to manipulate autophagy to evade degradation and immune responses. Porcine reproductive and respiratory syndrome virus (PRRSV) is a typical immunosuppressive virus that causes enormous economic losses in the swine industry. However, the mechanism by which PRRSV manipulates autophagy to defend against host antiviral effects remains unclear. In this study, we found that PRRSV GP5 interacts with LAMP2A and disrupts the formation of the GFAP-LAMP2A complex, thus inhibiting the activity of CMA and subsequently enhancing the inhibitory effect of the NSP11-mediated IFN-I signaling pathway, ultimately facilitating PRRSV replication. Our study revealed a novel mechanism by which PRRSV escapes host antiviral effects through CMA, providing a potential host target, LAMP2A, for developing antiviral drugs and contributing to understanding the escape mechanism of immunosuppressive viruses.
PubMed: 38940560
DOI: 10.1128/mbio.00532-24 -
Journal of Virology Jun 2024Viruses have evolved a range of strategies to utilize or manipulate the host's cellular translational machinery for efficient infection, although the mechanisms by which...
UNLABELLED
Viruses have evolved a range of strategies to utilize or manipulate the host's cellular translational machinery for efficient infection, although the mechanisms by which infectious bronchitis virus (IBV) manipulates the host translation machinery remain unclear. In this study, we firstly demonstrate that IBV infection causes host shutoff, although viral protein synthesis is not affected. We then screened 23 viral proteins, and identified that more than one viral protein is responsible for IBV-induced host shutoff, the inhibitory effects of proteins Nsp15 were particularly pronounced. Ribosome profiling was used to draw the landscape of viral mRNA and cellular genes expression model, and the results showed that IBV mRNAs gradually dominated the cellular mRNA pool, the translation efficiency of the viral mRNAs was lower than the median efficiency (about 1) of cellular mRNAs. In the analysis of viral transcription and translation, higher densities of RNA sequencing (RNA-seq) and ribosome profiling (Ribo-seq) reads were observed for structural proteins and 5' untranslated regions, which conformed to the typical transcriptional characteristics of nested viruses. Translational halt events and the number of host genes increased significantly after viral infection. The translationally paused genes were enriched in translation, unfolded-protein-related response, and activation of immune response pathways. Immune- and inflammation-related mRNAs were inefficiently translated in infected cells, and IBV infection delayed the production of IFN-β and IFN-λ. Our results describe the translational landscape of IBV-infected cells and demonstrate new strategies by which IBV induces host gene shutoff to promote its replication.
IMPORTANCE
Infectious bronchitis virus (IBV) is a γ-coronavirus that causes huge economic losses to the poultry industry. Understanding how the virus manipulates cellular biological processes to facilitate its replication is critical for controlling viral infections. Here, we used Ribo-seq to determine how IBV infection remodels the host's biological processes and identified multiple viral proteins involved in host gene shutoff. Immune- and inflammation-related mRNAs were inefficiently translated, the translation halt of unfolded proteins and immune activation-related genes increased significantly, benefitting IBV replication. These data provide new insights into how IBV modulates its host's antiviral responses.
PubMed: 38940559
DOI: 10.1128/jvi.00830-24 -
Journal of Virology Jun 2024Coronavirus disease 2019 (COVID-19) has claimed millions of lives since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and lung disease...
UNLABELLED
Coronavirus disease 2019 (COVID-19) has claimed millions of lives since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and lung disease appears the primary cause of death in COVID-19 patients. However, the underlying mechanisms of COVID-19 pathogenesis remain elusive, and there is no existing model where human disease can be faithfully recapitulated and conditions for the infection process can be experimentally controlled. Herein we report the establishment of an human precision-cut lung slice (hPCLS) platform for studying SARS-CoV-2 pathogenicity and innate immune responses, and for evaluating the efficacy of antiviral drugs against SARS-CoV-2. We show that while SARS-CoV-2 continued to replicate during the course of infection of hPCLS, infectious virus production peaked within 2 days, and rapidly declined thereafter. Although most proinflammatory cytokines examined were induced by SARS-CoV-2 infection, the degree of induction and types of cytokines varied significantly among hPCLS from individual donors. Two cytokines in particular, IP-10 and IL-8, were highly and consistently induced, suggesting a role in the pathogenesis of COVID-19. Histopathological examination revealed focal cytopathic effects late in the infection. Transcriptomic and proteomic analyses identified molecular signatures and cellular pathways that are largely consistent with the progression of COVID-19 in patients. Furthermore, we show that homoharringtonine, a natural plant alkaloid derived from , not only inhibited virus replication but also production of pro-inflammatory cytokines, and thus ameliorated the histopathological changes caused by SARS-CoV-2 infection, demonstrating the usefulness of the hPCLS platform for evaluating antiviral drugs.
IMPORTANCE
Here, established an human precision-cut lung slice platform for assessing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, viral replication kinetics, innate immune response, disease progression, and antiviral drugs. Using this platform, we identified early induction of specific cytokines, especially IP-10 and IL-8, as potential predictors for severe coronavirus disease 2019 (COVID-19), and uncovered a hitherto unrecognized phenomenon that while infectious virus disappears at late times of infection, viral RNA persists and lung histopathology commences. This finding may have important clinical implications for both acute and post-acute sequelae of COVID-19. This platform recapitulates some of the characteristics of lung disease observed in severe COVID-19 patients and is therefore a useful platform for understanding mechanisms of SARS-CoV-2 pathogenesis and for evaluating the efficacy of antiviral drugs.
PubMed: 38940558
DOI: 10.1128/jvi.00794-24 -
Frontiers in Cellular and Infection... 2024Hand, foot, and mouth disease (HFMD) is a common infectious disease caused by enterovirus 71 (EV71) that frequently affects children, leading to severe infections in...
Hand, foot, and mouth disease (HFMD) is a common infectious disease caused by enterovirus 71 (EV71) that frequently affects children, leading to severe infections in some cases. In general, when infection occurs, the body upregulates inflammatory responses to eliminate pathogenic microorganisms to protect the host from infection. However, EV71 may inhibit host's innate immunity to promote virus infection. At present, it is not fully understood how EV71 hijack the host cells for its own replication. Toll-like receptor 4 (TLR4), a natural immune receptor, historically associated with bacterial endotoxin-induced inflammatory responses. However, it is still unclear whether and how TLR4 is altered during EV71 infection. In this study, we observed a reduction in both TLR4 protein and gene transcript levels in RD, GES-1, and Vero cells following EV71 infection, as detected by RT-qPCR, immunofluorescence staining and western blot. Furthermore, we observed that the TLR4 downstream molecules of MYD88, p-NF-κB p65, p-TBK1 and related inflammatory cytokines were also reduced, suggesting that antiviral innate immune and inflammatory response were suppressed. To determine the impact of TLR4 changes on EV71 infection, we interfered EV71-infected RD cells with TLR4 agonist or inhibitor and the results showed that activation of TLR4 inhibited EV71 replication, while inhibition of TLR4 promote EV71 replication. Besides, EV71 replication was also promoted in TLR4 siRNA-transfected and EV71-infected RD cells. This suggests that down-regulation the expression of TLR4 by EV71 can inhibit host immune defense to promote EV71 self-replication. This novel mechanism may be a strategy for EV71 to evade host immunity.
Topics: Toll-Like Receptor 4; Enterovirus A, Human; Humans; Virus Replication; Signal Transduction; Animals; Vero Cells; Chlorocebus aethiops; Immunity, Innate; Host-Pathogen Interactions; Inflammation; Myeloid Differentiation Factor 88; Cell Line; Protein Serine-Threonine Kinases; Cytokines; NF-kappa B; Hand, Foot and Mouth Disease
PubMed: 38938877
DOI: 10.3389/fcimb.2024.1393680