Protein kinase B/Akt regulates coxsackievirus B3 replication through a mechanism which is not caspase dependent

Network pharmacology and bioinformatics analysis identifies potential therapeutic targets of Naringenin against COVID-19/LUSC

Background

Coronavirus disease 2019 (COVID-19) is a highly contagious respiratory disease that has posed a serious threat to people's daily lives and caused an unprecedented challenge to public health and people's health worldwide. Lung squamous cell carcinoma (LUSC) is a common type of lung malignancy with a highly aggressive nature and poor prognosis. Patients with LUSC could be at risk for COVID-19, We conducted this study to examine the potential for naringenin to develop into an ideal medicine and investigate the underlying action mechanisms of naringenin in COVID-19 and LUSC due to the anti-viral, anti-tumor, and anti-inflammatory activities of naringenin.

Methods

LUSC related genes were obtained from TCGA, PharmGKB, TTD,GeneCards and NCBI, and then the transcriptome data for COVID-19 was downloaded from GEO, DisGeNET, CTD, DrugBank, PubChem, TTD, NCBI Gene, OMIM. The drug targets of Naringenin were revealed through CTD, BATMAN, TCMIP, SymMap, Chemical Association Networks, SwissTargetPrediction, PharmMapper, ECTM, and DGIdb. The genes related to susceptibility to COVID-19 in LUSC patients were obtained through differential analysis. The interaction of COVID-19/LUSC related genes was evaluated and demonstrated using STRING to develop a a COX risk regression model to screen and evaluate the association of genes with clinical characteristics. To investigate the related functional and pathway analysis of the common targets of COVID-19/LUSC and Naringenin, KEGG and GO enrichment analysis were employed to perform the functional analysis of the target genes. Finally, The Hub Gene was screened and visualized using Cytoscape, and molecular docking between the drug and the target was performed using Autodock.

Results

We discovered numerous COVID-19/LUSC target genes and examined their prognostic value in LUSC patients utilizing a variety of bioinformatics and network pharmacology methods. Furthermore, a risk score model with strong predictive performance was developed based on these target genes to assess the prognosis of LUSC patients with COVID-19. We intersected the therapeutic target genes of naringenin with the LUSC, COVID-19-related targets, and identified 354 common targets, which could be used as potential target genes for naringenin to treat COVID-19/LUSC. The treatment of COVID-19/LUSC with naringenin may involve oxidative stress, anti-inflammatory, antiviral, antiviral, apoptosis, immunological, and multiple pathways containing PI3K-Akt, HIF-1, and VEGF, according to the results of the GO and KEGG enrichment analysis of these 354 common targets. By constructing a PPI network, we ascertained AKT1, TP53, SRC, MAPK1, MAPK3, and HSP90AA1 as possible hub targets of naringenin for the treatment of COVID-19/LUSC. Last but not least, molecular docking investigations showed that naringenin has strong binding activity in COVID-19/LUSC.

Conclusion

We revealed for the first time the pharmacological targets and potential molecular processes of naringenin for the treatment of COVID-19/LUSC. However, these results need to be confirmed by additional research and validation in real LUSC patients with COVID-19.

Repurposing Amphotericin B and Its Liposomal Formulation for the Treatment of Human Mpox

Mpox (monkeypox) is a zoonotic viral disease caused by the mpox virus (MPXV). Recently in 2022, a multi-country Mpox outbreak has determined great concern as the disease rapidly spreads. The majority of cases are being noticed in European regions and are unrelated to endemic travel or known contact with infected individuals. In this outbreak, close sexual contact appears to be important for MPXV transmission, and an increasing prevalence in people with multiple sexual partners and in men who have sex with men has been observed. Although Vaccinia virus (VACV)-based vaccines have been shown to induce a cross-reactive and protective immune response against MPXV, limited data support their efficacy against the 2022 Mpox outbreak. Furthermore, there are no specific antiviral drugs for Mpox. Host-cell lipid rafts are small, highly dynamic plasma-membrane microdomains enriched in cholesterol, glycosphingolipids and phospholipids that have emerged as crucial surface-entry platforms for several viruses. We previously demonstrated that the antifungal drug Amphotericin B (AmphB) inhibits fungal, bacterial and viral infection of host cells through its capacity to sequester host-cell cholesterol and disrupt lipid raft architecture. In this context, we discuss the hypothesis that AmphB could inhibit MPXV infection of host cells through disruption of lipid rafts and eventually through redistribution of receptors/co-receptors mediating virus entry, thus representing an alternative or additional therapeutic tool for human Mpox.

Deciphering suppressive effects of Lianhua Qingwen Capsule on COVID-19 and synergistic effects of its major botanical drug pairs

The COVID-19 pandemic has resulted in excess deaths worldwide. Conventional antiviral medicines have been used to relieve the symptoms, with limited therapeutic effect. In contrast, Lianhua Qingwen Capsule is reported to exert remarkable anti-COVID-19 effect. The current review aims to: 1) uncover the main pharmacological actions of Lianhua Qingwen Capsule for managing COVID-19; 2) verify the bioactive ingredients and pharmacological actions of Lianhua Qingwen Capsule by network analysis; 3) investigate the compatibility effect of major botanical drug pairs in Lianhua Qingwen Capsule; and 4) clarify the clinical evidence and safety of the combined therapy of Lianhua Qingwen Capsule and conventional drugs. Numerous bioactive ingredients in Lianhu Qingwen, such as quercetin, naringenin, β-sitosterol, luteolin, and stigmasterol, were identified to target host cytokines, and to regulate the immune defence in response to COVID-19. Genes including androgen receptor (AR), myeloperoxidase (MPO), epidermal growth factor receptor (EGFR), insulin (INS), and aryl hydrocarbon receptor (AHR) were found to be significantly involved in the pharmacological actions of Lianhua Qingwen Capsule against COVID-19. Four botanical drug pairs in Lianhua Qingwen Capsule were shown to have synergistic effect for the treatment of COVID-19. Clinical studies demonstrated the medicinal effect of the combined use of Lianhua Qingwen Capsule and conventional drugs against COVID-19. In conclusion, the four main pharmacological mechanisms of Lianhua Qingwen Capsule for managing COVID-19 are revealed. Therapeutic effect has been noted against COVID-19 in Lianhua Qingwen Capsule.

Immunostimulatory oncolytic activity of coxsackievirus A11 in human malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive solid cancer with a poor prognosis, whereas coxsackievirus A11 (CVA11) is a potential oncolytic virus for cancer treatment. We here investigated the oncolytic activity of CVA11 with human MPM cell lines. CVA11 infection was cytotoxic in all six MPM cell lines examined and showed no or minimal cytotoxicity toward normal human normal cell lines. MPM cells with a higher surface level of intercellular adhesion molecule-1 (ICAM-1) expression tended to be more susceptible to CVA11-induced cytotoxicity, and a neutralizing antibody to ICAM-1 attenuated such cytotoxicity. CVA11 infection activated signaling by Akt and extracellular signal-regulated kinase (ERK) pathways, and inhibitors of such signaling also abrogated CVA11-mediated cytotoxicity. Furthermore, CVA11 infection-triggered multiple modes of tumor cell death including apoptosis, pyroptosis, and necroptosis, and such death was accompanied by the release or exposure of the proinflammatory cytokine interleukin-1β and damage-associated molecular patterns such as calreticulin, high-mobility group box-1, annexin A1, and heat shock protein 70, which are hallmarks of immunogenic cell death. Notably, in vivo treatment of human MPM xenografts with intratumoral CVA11 injection resulted in significant suppression of tumor growth in SCID mice, and all mice infected with CVA11 showed no significant change in body weight. Our findings collectively suggest that the oncolytic activity of CVA11 for MPM is dependent on ICAM-1 as a virus receptor, as well as on Akt and ERK signaling, and that oncolytic virotherapy with CVA11 is a promising treatment modality with immunostimulatory activity for human MPM.

Modeling Kaempferol as a Potential Pharmacological Agent for COVID-19/PF Co-Occurrence Based on Bioinformatics and System Pharmacological Tools

Objective: People suffering from coronavirus disease 2019 (COVID-19) are prone to develop pulmonary fibrosis (PF), but there is currently no definitive treatment for COVID-19/PF co-occurrence. Kaempferol with promising antiviral and anti-fibrotic effects is expected to become a potential treatment for COVID-19 and PF comorbidities. Therefore, this study explored the targets and molecular mechanisms of kaempferol against COVID-19/PF co-occurrence by bioinformatics and network pharmacology.

Methods: Various open-source databases and Venn Diagram tool were applied to confirm the targets of kaempferol against COVID-19/PF co-occurrence. Protein-protein interaction (PPI), MCODE, key transcription factors, tissue-specific enrichment, molecular docking, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to clarify the influential molecular mechanisms of kaempferol against COVID-19 and PF comorbidities.

Results: 290 targets and 203 transcription factors of kaempferol against COVID-19/PF co-occurrence were captured. Epidermal growth factor receptor (EGFR), proto-oncogene tyrosine-protein kinase SRC (SRC), mitogen-activated protein kinase 3 (MAPK3), mitogen-activated protein kinase 1 (MAPK1), mitogen-activated protein kinase 8 (MAPK8), RAC-alpha serine/threonine-protein kinase (AKT1), transcription factor p65 (RELA) and phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform (PIK3CA) were identified as the most critical targets, and kaempferol showed effective binding activities with the above critical eight targets. Further, anti-COVID-19/PF co-occurrence effects of kaempferol were associated with the regulation of inflammation, oxidative stress, immunity, virus infection, cell growth process and metabolism. EGFR, interleukin 17 (IL-17), tumor necrosis factor (TNF), hypoxia inducible factor 1 (HIF-1), phosphoinositide 3-kinase/AKT serine/threonine kinase (PI3K/AKT) and Toll-like receptor signaling pathways were identified as the key anti-COVID-19/PF co-occurrence pathways.

Conclusion: Kaempferol is a candidate treatment for COVID-19/PF co-occurrence. The underlying mechanisms may be related to the regulation of critical targets (EGFR, SRC, MAPK3, MAPK1, MAPK8, AKT1, RELA, PIK3CA and so on) and EGFR, IL-17, TNF, HIF-1, PI3K/AKT and Toll-like receptor signaling pathways. This study contributes to guiding development of new drugs for COVID-19 and PF comorbidities.

A Practical Strategy for Exploring the Pharmacological Mechanism of Luteolin Against COVID-19/Asthma Comorbidity: Findings of System Pharmacology and Bioinformatics Analysis

Asthma patients may increase their susceptibility to SARS-CoV-2 infection and the poor prognosis of coronavirus disease 2019 (COVID-19). However, anti-COVID-19/asthma comorbidity approaches are restricted on condition. Existing evidence indicates that luteolin has antiviral, anti-inflammatory, and immune regulation capabilities. We aimed to evaluate the possibility of luteolin evolving into an ideal drug and explore the underlying molecular mechanisms of luteolin against COVID-19/asthma comorbidity. We used system pharmacology and bioinformatics analysis to assess the physicochemical properties and biological activities of luteolin and further analyze the binding activities, targets, biological functions, and mechanisms of luteolin against COVID-19/asthma comorbidity. We found that luteolin may exert ideal physicochemical properties and bioactivity, and molecular docking analysis confirmed that luteolin performed effective binding activities in COVID-19/asthma comorbidity. Furthermore, a protein–protein interaction network of 538 common targets between drug and disease was constructed and 264 hub targets were obtained. Then, the top 6 hub targets of luteolin against COVID-19/asthma comorbidity were identified, namely, TP53, AKT1, ALB, IL-6, TNF, and VEGFA. Furthermore, the enrichment analysis suggested that luteolin may exert effects on virus defense, regulation of inflammation, cell growth and cell replication, and immune responses, reducing oxidative stress and regulating blood circulation through the Toll-like receptor; MAPK, TNF, AGE/RAGE, EGFR, ErbB, HIF-1, and PI3K–AKT signaling pathways; PD-L1 expression; and PD-1 checkpoint pathway in cancer. The possible “dangerous liaison” between COVID-19 and asthma is still a potential threat to world health. This research is the first to explore whether luteolin could evolve into a drug candidate for COVID-19/asthma comorbidity. This study indicated that luteolin with superior drug likeness and bioactivity has great potential to be used for treating COVID-19/asthma comorbidity, but the predicted results still need to be rigorously verified by experiments.

Protein Kinase B2 (PKB2/AKT2) Is Essential for Host Protection in CVB3-Induced Acute Viral Myocarditis

Protein kinase B2 (AKT2) is involved in various cardiomyocyte signaling processes, including those important for survival and metabolism. Coxsackievirus B3 (CVB3) is one of the most common pathogens that cause myocarditis in humans. The role of AKT2 in CVB3 infection is not yet well understood. We used a cardiac-specific AKT2 knockout (KO) mouse to determine the role of AKT2 in CVB3-mediated myocarditis. CVB3 was injected intraperitoneally into wild-type (WT) and KO mice. The mice’s survival rate was recorded: survival in KO mice was significantly decreased compared with WT mice (WT vs. KO: 73.3 vs. 27.1%). Myocardial damage and inflammation were significantly increased in the hearts of KO mice compared with those of WT mice. Moreover, from surface ECG, AKT2 KO mice showed a prolonged atria and ventricle conduction time (PR interval, WT vs. KO: 47.27 ± 1.17 vs. 64.79 ± 7.17 ms). AKT2 deletion induced severe myocarditis and cardiac dysfunction due to CVB3 infection. According to real-time PCR, the mRNA level of IL-1, IL-6, and TNF-α decreased significantly in KO mice compared with WT mice on Days 5 after infection. In addition, innate immune response antiviral effectors, Type I interferon (interferon-α and β), and p62, were dramatically suppressed in the heart of KO mice. In particular, the adult cardiac myocytes isolated from the heart showed high induction of TLR4 protein in KO mice in comparison with WT. AKT2 deletion suppressed the activation of Type I interferon and p62 transcription in CVB3 infection. In cardiac myocytes, AKT2 is a key signaling molecule for the heart from damage through the activation of innate immunity during acute myocarditis.

Role of apoptosis in Duck Tembusu virus infection of duckling brains in vivo

The Duck Tembusu virus (DTMUV) is a novel flavivirus that occurs mainly in poultry. DTMUV infection can cause common neurological symptoms in ducklings, but the pathogenesis of DTMUV has not been elucidated yet. In this study, a DTMUV-infected duckling model was constructed to investigate the apoptosis in the duckling brains. After DTMUV infection, apoptotic cells were observed by transmission electron microscopy. It was found that the abundances of apoptosis-related genes and proteins were not obviously changed in the early stage of infection but significantly changed in the middle and late stages of the disease. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay staining results were also consistent with the above phenomena. Interestingly, although apoptosis occurred in the duckling brains infected by DTMUV, some antiapoptotic genes in the brain increased in varying degrees. In conclusion, DTMUV infection could induce apoptosis in ducklings' brains, and the occurrence of apoptosis was accompanied by the virus infection process with certain regularity. This study provides a scientific basis for elucidating the apoptotic mechanism of brain lesions induced by DTMUV infection.

Using oncolytic viruses to ignite the tumour immune microenvironment in bladder cancer

The advent of immune checkpoint inhibition (ICI) has transformed the treatment paradigm for bladder cancer. However, despite the success of ICI in other tumour types, the majority of ICI-treated patients with bladder cancer failed to respond. The lack of efficacy in some patients could be attributed to a paucity of pre-existing immune reactive cells within the tumour immune microenvironment, which limits the beneficial effects of ICI. In this setting, strategies to attract lymphocytes before implementation of ICI could be helpful. Oncolytic virotherapy is thought to induce the release of damage-associated molecular patterns, eliciting a pro-inflammatory cytokine cascade and stimulating the activation of the innate immune system. Concurrently, oncolytic virotherapy-induced oncolysis leads to further release of neoantigens and subsequent epitope spreading, culminating in a robust, tumour-specific adaptive immune response. Combination therapy using oncolytic virotherapy with ICI has proven successful in a number of preclinical studies and is beginning to enter clinical trials for the treatment of both non-muscle-invasive and muscle-invasive bladder cancer. In this context, understanding of the mechanisms underpinning oncolytic virotherapy and its potential synergism with ICI will enable clinicians to effectively deploy oncolytic virotherapy, either as monotherapy or as combination therapy in the different clinical stages of bladder cancer.

Identifying the molecular targets and mechanisms of xuebijing injection for the treatment of COVID-19 via network parmacology and molecular docking

Xuebijing Injection have been found to improve the clinical symptoms of COVID-19 and alleviate disease severity, but the mechanisms are currently unclear. This study aimed to investigate the potential molecular targets and mechanisms of the Xuebijing injection in treating COVID-19 via network pharmacology and molecular docking analysis. The main active ingredients and therapeutic targets of the Xuebijing injection, and the pathogenic targets of COVID-19 were screened using the TCMSP, UniProt, and GeneCard databases. According to the ‘Drug-Ingredients-Targets-Disease’ network built by STRING and Cytoscape, AKT1 was identified as the core target, and baicalein, luteolin, and quercetin were identified as the active ingredients of the Xuebijing injection in connection with AKT1. R language was used for enrichment analysis that predict the mechanisms by which the Xuebijing injection may inhibit lipopolysaccharide-mediated inflammatory response, modulate NOS activity, and regulate the TNF signal pathway by affecting the role of AKT1. Based on the results of network pharmacology, a molecular docking was performed with AKT1 and the three active ingredients, the results indicated that all three active ingredients could stably bind with AKT1. These findings identify potential molecular mechanisms by which Xuebijing Injection inhibit COVID-19 by acting on AKT1.

Development of Group B Coxsackievirus as an Oncolytic Virus: Opportunities and Challenges

Oncolytic viruses have emerged as a promising strategy for cancer therapy due to their dual ability to selectively infect and lyse tumor cells and to induce systemic anti-tumor immunity. Among various candidate viruses, coxsackievirus group B (CVBs) have attracted increasing attention in recent years. CVBs are a group of small, non-enveloped, single-stranded, positive-sense RNA viruses, belonging to species human Enterovirus B in the genus Enterovirus of the family Picornaviridae. Preclinical studies have demonstrated potent anti-tumor activities for CVBs, particularly type 3, against multiple cancer types, including lung, breast, and colorectal cancer. Various approaches have been proposed or applied to enhance the safety and specificity of CVBs towards tumor cells and to further increase their anti-tumor efficacy. This review summarizes current knowledge and strategies for developing CVBs as oncolytic viruses for cancer virotherapy. The challenges arising from these studies and future prospects are also discussed in this review.

Differential Expression of Serum Exosome microRNAs and Cytokines in Influenza A and B Patients Collected in the 2016 and 2017 Influenza Seasons

MicroRNAs (miRNAs) have remarkable stability and are key regulators of mRNA transcripts for several essential proteins required for the survival of cells and replication of the virus. Exosomes are thought to play an essential role in intercellular communications by transporting proteins and miRNAs, making them ideal in the search for biomarkers. Evidence suggests that miRNAs are involved in the regulation of influenza virus replication in many cell types. During the 2016 and 2017 influenza season, we collected blood samples from 54 patients infected with influenza and from 30 healthy volunteers to identify the potential role of circulating serum miRNAs and cytokines in influenza infection. Data comparing the exosomal miRNAs in patients with influenza B to healthy volunteers showed 76 miRNAs that were differentially expressed (p < 0.05). In contrast, 26 miRNAs were differentially expressed between patients with influenza A (p < 0.05) and the controls. Of these miRNAs, 11 were commonly expressed in both the influenza A and B patients. Interferon (IFN)-inducing protein 10 (IP-10), which is involved in IFN synthesis during influenza infection, showed the highest level of expression in both influenza A and B patients. Influenza A patients showed increased expression of IFNα, GM-CSF, interleukin (IL)-13, IL-17A, IL-1β, IL-6 and TNFα, while influenza B induced increased levels of EGF, G-CSF, IL-1α, MIP-1α, and TNF-β. In addition, hsa-miR-326, hsa-miR-15b-5p, hsa-miR-885, hsa-miR-122-5p, hsa-miR-133a-3p, and hsa-miR-150-5p showed high correlations to IL-6, IL-15, IL-17A, IL-1β, and monocyte chemoattractant protein-1 (MCP-1) with both strains of influenza. Next-generation sequencing studies of H1N1-infected human lung small airway epithelial cells also showed similar pattern of expression of miR-375-5p, miR-143-3p, 199a-3p, and miR-199a-5p compared to influenza A patients. In summary, this study provides insights into the miRNA profiling in both influenza A and B virus in circulation and a novel approach to identify the early infections through a combination of cytokines and miRNA expression.

Network pharmacology and molecular docking analyses on Lianhua Qingwen capsule indicate Akt1 is a potential target to treat and prevent COVID-19

Objectives

Coronavirus disease 2019 (COVID‐19) is rapidly spreading worldwide. Lianhua Qingwen capsule (LQC) has shown therapeutic effects in patients with COVID‐19. This study is aimed to discover its molecular mechanism and provide potential drug targets.

Materials and Methods

An LQC target and COVID‐19–related gene set was established using the Traditional Chinese Medicine Systems Pharmacology database and seven disease‐gene databases. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and protein‐protein interaction (PPI) network were performed to discover the potential mechanism. Molecular docking was performed to visualize the patterns of interactions between the effective molecule and targeted protein.

Results

A gene set of 65 genes was generated. We then constructed a compound‐target network that contained 234 nodes of active compounds and 916 edges of compound‐target pairs. The GO and KEGG indicated that LQC can act by regulating immune response, apoptosis and virus infection. PPI network and subnetworks identified nine hub genes. The molecular docking was conducted on the most significant gene Akt1, which is involved in lung injury, lung fibrogenesis and virus infection. Six active compounds of LQC can enter the active pocket of Akt1, namely beta‐carotene, kaempferol, luteolin, naringenin, quercetin and wogonin, thereby exerting potential therapeutic effects in COVID‐19.

Conclusions

The network pharmacological strategy integrates molecular docking to unravel the molecular mechanism of LQC. Akt1 is a promising drug target to reduce tissue damage and help eliminate virus infection.

Regulation of Apoptosis by Enteroviruses

Enterovirus infection can cause a variety of diseases and severely impair the health of humans, animals, poultry, and other organisms. To resist viral infection, host organisms clear infected cells and viruses via apoptosis. However, throughout their long-term competition with host cells, enteroviruses have evolved a series of mechanisms to regulate the balance of apoptosis in order to replicate and proliferate. In the early stage of infection, enteroviruses mainly inhibit apoptosis by regulating the PI3K/Akt pathway and the autophagy pathway and by impairing cell sensors, thereby delaying viral replication. In the late stage of infection, enteroviruses mainly regulate apoptotic pathways and the host translation process via various viral proteins, ultimately inducing apoptosis. This paper discusses the means by which these two phenomena are balanced in enteroviruses to produce virus-favoring conditions – in a temporal sequence or through competition with each other. This information is important for further elucidation of the relevant mechanisms of acute infection by enteroviruses and other members of the picornavirus family.

Inhibition of RNA Helicase Activity Prevents Coxsackievirus B3-Induced Myocarditis in Human iPS Cardiomyocytes

AIMS

Coxsackievirus B3 (CVB3) is known to be an important cause of myocarditis and dilated cardiomyopathy. Enterovirus-2C (E2C) is a viral RNA helicase. It inhibits host protein synthesis. Based on these facts, we hypothesize that the inhibition of 2C may suppress virus replication and prevent enterovirus-mediated cardiomyopathy.

METHODS AND RESULTS

We generated a chemically modified enterovirus-2C inhibitor (E2CI). From the in vitro assay, E2CI was showed strong antiviral effects. For in vivo testing, mice were treated with E2CI intraperitoneally injected daily for three consecutive days at a dose of 8mg/kg per day, after CVB3 post-infection (p.i) (CVB3 + E2CI, n = 33). For the infected controls (CVB3 only, n = 35), mice were injected with PBS (phosphate buffered saline) in a DBA/2 strain to establish chronic myocarditis. The four-week survival rate of E2CI-treated mice was significantly higher than that of controls (92% vs. 71%; p < 0.05). Virus titers and myocardial damage were significantly reduced in the E2CI treated group. In addition, echocardiography indicated that E2CI administration dramatically maintained mouse heart function compared to control at day 28 p.i chronic stage (LVIDD, 3.1 ± 0.08 vs. 3.9 ± 0.09, p < 0.01; LVDS, 2.0 ± 0.07 vs. 2.5 ± 0.07, p < 0.001; FS, 34.8 ± 1.6% vs. 28.5 ± 1.5%; EF, 67. 9 ± 2.9% vs. 54.7 ± 4.7%, p < 0.05; CVB3 + E2CI, n = 6 vs. CVB3, n = 4). Moreover, E2CI is effectively worked in human iPS (induced pluripotent stem cell) derived cardiomyocytes.

CONCLUSION

Enterovirus-2C inhibitor (E2CI) was significantly reduced viral replication, chronic myocardium damage, and CVB3-induced mortality in DBA/2 mice. These results suggested that E2CI is a novel therapeutic agent for the treatment of enterovirus-mediated diseases.

Salvianolic Acid B Inhibits Hand-Foot-Mouth Disease Enterovirus 71 Replication through Enhancement of AKT Signaling Pathway

Hand, foot, and mouth disease (HFMD) is caused by enterovirus 71 (EV71) in infants and children under six years of age. HFMD is characterized by fever, mouth ulcers, and vesicular rashes on the palms and feet. EV71 also causes severe neurological manifestations, such as brainstem encephalitis and aseptic meningitis. Recently, frequent outbreaks of EV71 have occurred in the Asia-Pacific region, but currently, no effective antiviral drugs have been developed to treat the disease. In this study, we investigated the antiviral effect of salvianolic acid B (SalB) on EV71. SalB is a major component of the Salvia miltiorrhiza root and has been shown to be an effective treatment for subarachnoid hemorrhages and myocardial infarctions. HeLa cells were cultured in 12-well plates and treated with SalB (100 or 10 µg/ml) and 10⁶ PFU/ml of EV71. SalB treatment (100 µg/ml) significantly decreased the cleavage of the eukaryotic eIF4G1 protein and reduced the expression of the EV71 capsid protein VP1. In addition, SalB treatment showed a dramatic decrease in viral infection, measured by immunofluorescence staining. The Akt signaling pathway, a key component of cell survival and proliferation, was significantly increased in EV71-infected HeLa cells treated with 100 µg/ml SalB. RT-PCR results showed that the mRNA for anti-apoptotic protein Bcl-2 and the cell cycle regulator Cyclin-D1 were significantly increased by SalB treatment. These results indicate that SalB activates Akt/PKB signaling and inhibits apoptosis in infected HeLa cells. Taken together, these results suggest that SalB could be used to develop a new therapeutic drug for EV71-induced HFMD.

The forkhead transcription factor Foxo3 negatively regulates natural killer cell function and viral clearance in myocarditis

Aims

Foxo3 is a transcription factor involved in cell metabolism, survival, and inflammatory disease. However, mechanistic insight in Foxo3 effects is still limited. Here, we investigated the role of Foxo3 on natural killer (NK) cell responses and its effects in viral myocarditis.

Methods and results

Effects of Foxo3 on viral load and immune responses were investigated in a model of coxsackie virus B3 myocarditis in wild-type (WT) and Foxo3 deficient mice. Reduced immune cell infiltration, viral titres, and pro-inflammatory cytokines in cardiac tissue were observed in Foxo3-/- mice 7 days post-infection (p.i.). Viral titres were also attenuated in hearts of Foxo3-/- mice at Day 3 while interferon-γ (IFNγ) and NKp46 expression were up-regulated suggesting early viral control by enhanced NK cell activity. CD69 expression of NK cells, frequencies of CD11b+CD27+ effector NK cells and cytotoxicity of Foxo3-/- mice was enhanced compared to WT littermates. Moreover, microRNA-155 expression, essential in NK cell activation, was elevated in Foxo3-/- NK cells while its inhibition led to diminished IFNγ production. Healthy humans carrying the longevity-associated FOXO3 single nucleotide polymorphism (SNP) rs12212067 exhibited reduced IFNγ and cytotoxic degranulation of NK cells. Viral inflammatory cardiomyopathy (viral CMI) patients with this SNP showed a poorer outcome due to less efficient virus control.

Conclusion

Our results implicate Foxo3 in regulating NK cell function and suggest Foxo3 playing an important role in the antiviral innate immunity. Thus, enhanced FOXO3 activity such as in the polymorphism rs12212067 may be protective in chronic inflammation such as cancer and cardiovascular disease but disadvantageous to control acute viral infection.

Cell Adhesion by Integrins

Integrins are heterodimeric cell surface receptors ensuring the mechanical connection between cells and the extracellular matrix. In addition to the anchorage of cells to the extracellular matrix, these receptors have critical functions in intracellular signaling, but are also taking center stage in many physiological and pathological conditions. In this review, we provide some historical, structural, and physiological notes so that the diverse functions of these receptors can be appreciated and put into the context of the emerging field of mechanobiology. We propose that the exciting journey of the exploration of these receptors will continue for at least another new generation of researchers.

Modulation of Type-I Interferon Response by hsa-miR-374b-5p During Japanese Encephalitis Virus Infection in Human Microglial Cells

Japanese Encephalitis virus (JEV) is a neurotropic ssRNA virus, belonging to the Flaviviridae family. JEV is one of the leading causes of the viral encephalitis in Southeast-Asian countries. JEV primarily infects neurons however, the microglial activation has been reported to further enhance the neuroinflammation and promote neuronal death. The PI3K/AKT pathway has been reported to play an important role in type-I interferon response via IRF3. Phosphatase and tensin homolog (PTEN), a negative regulator of PI3K/AKT pathway, participates in microglial polarization and neuroinflammation. The microRNAs are small non-coding endogenously expressed RNAs, which regulate the gene expression by binding at 3′ UTR of target gene. The human microglial cells were infected with JEV (JaOArS982 strain) and up-regulation of microRNA; hsa-miR-374b-5p was confirmed by qRT-PCR. The genes in PI3K/AKT pathway, over-expression and knock-down studies of hsa-miR-374b-5p with and without JEV infection were analyzed through immuno blotting. The regulatory role of hsa-miR-374b-5p on the expression of type-I interferon was determined by luciferase assays. JEV infection modulated the expression of hsa-miR-374b-5p and PI3K/AKT pathway via PTEN. The over-expression of hsa-miR-374b-5p suppressed the PTEN while up-regulated the AKT and IRF3 proteins, whereas, the knockdown rescued the PTEN expression and suppressed the AKT and IRF3 proteins. The modulation of hsa-miR-374b-5p regulated the type-I interferon response during JEV infection. In present study, we have shown the modulation of PTEN by hsa-miR-374b-5p, which regulated the PI3K/AKT/IRF3 axis in JEV infected microglial cells.

Molecular detection of Hsp90 inhibitor suppressing PCV2 replication in host cells

Porcine Circovirus Type 2 (PCV2) is a pathogen that has the ability to cause devastating disease manifestations in pig populations with major economic implications. Our previous research found that Hsp90 is required for PCV2 production in PK-15 and 3D4/31 cells. The aim of this study was to evaluate the effect of Hsp90 inhibitor regulating PCV2 replication and to explore its underlying mechanism. In PK-15 and 3D4/31 cells treated with 17-AAG after viral adsorption, replication of PCV2 was attenuated as assessed by quantitating the expression of viral protein. Following NF-κB activation it was observed that 24hpi with PCV2 was significantly inhibited in the presence of 17-AAG. The expression of Hsp90 associated client proteins in PCV2-infected cells were also reduced in the presence of 17-AAG. However, treatment with MG-132 failed to rescue 17-AAG mediated reduction of PCV2 production in host cells. Thus, Hsp90 regulates PCV2 by modulating cellular signaling proteins. These results highlight the importance of cellular proteins during PCV2 infection and the possibility of targeting cellular chaperones for developing new anti-rotaviral strategies.

Screening of PI3K-Akt-targeting Drugs for Silkworm against Bombyx mori Nucleopolyhedrovirus

Bombyx mori nucleopolyhedrovirus (BmNPV) is the most prevalent threat to silkworms. Hence, there is a need for antiviral agents in sericulture. The PI3K-Akt pathway is essential for the efficient replication of the baculovirus. In an attempt to screen antiviral drugs against BmNPV, we summarized the commercial compounds targeting PI3K-Akt and selected the following seven oral drugs for further analyses: afuresertib, AZD8835, AMG319, HS173, AS605240, GDC0941, and BEZ235. Cell viability assay revealed that the cytotoxicity of these drugs at 10 µM concentration was not strong. Viral fluorescence observation and qPCR analysis showed that these candidate drugs significantly inhibited BmNPV in BmE cells. Only AMG319 and AZD8835 inhibited viral proliferation in silkworm larvae. The mortality of AZD8835-treated silkworms was lower than that of the control silkworms. Western blotting showed that AMG319 and AZD8835 decreased p-Akt expression after BmNPV infection. These results suggest that AZD8835 has application potential in sericulture.

Antiviral activity against enterovirus 71 of sulfated rhamnan isolated from the green alga Monostroma latissimum

Polysaccharide from Monostroma latissimum PML is a sulfated rhamnan, which consists of →3)-α-L-Rhap-(1→ and →2)-α-L-Rhap-(1→ residues with partial branches and sulfate groups at C-2 of →3)-α-L-Rhap-(1→ and/or C-3 of →2)-α-L-Rhap-(1→. The anti-enterovirus 71 (EV71) activity in vitro of PML was assessed by cytopathic effect inhibition and plaque reduction assays, and the results showed that PML was non-cytotoxic and significantly inhibited EV71 infection. The mechanism analysis of anti-EV71 activity demonstrated that PML largely inhibited viral replication before or during viral adsorption, mainly by targeting the capsid protein VP1. PML may also inhibit some early steps of infection after viral adsorption by modulating signaling through the epidermal growth factor receptor (EGFR)/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway. Moreover, PML markedly improved survival and decreased viral titers in EV71-infected mice. The investigation revealed that PML has potential as a novel anti-EV71 agent targeting the viral capsid protein as well as cellular EGFR/PI3K/Akt pathway.

Respiratory Manifestations of the Activated Phosphoinositide 3-Kinase Delta Syndrome

The activated phosphoinositide 3-kinase δ syndrome (APDS), also known as p110δ-activating mutation causing senescent T cells, lymphadenopathy, and immunodeficiency (PASLI), is a combined immunodeficiency syndrome caused by gain-of-function mutations in the phosphoinositide 3-kinase (PI3K) genes PIK3CD (encoding p110δ: APDS1 or PASLI-CD) and PIK3R1 (encoding p85α: APDS2 or PASLI-R1). While the disease is clinically heterogeneous, respiratory symptoms and complications are near universal and often severe. Infections of the ears, sinuses, and upper and lower respiratory tracts are the earliest and most frequent manifestation of APDS, secondary to both respiratory viruses and to bacterial pathogens typical of defective B cell function. End organ damage in the form of small airways disease and bronchiectasis frequently complicates APDS, but despite documented T cell defects, opportunistic infections have rarely been observed. Antimicrobial (principally antibiotic) prophylaxis and/or immunoglobulin replacement have been widely used to reduce the frequency and severity of respiratory infection in APDS, but outcome data to confirm the efficacy of these interventions are limited. Despite these measures, APDS patients are often afflicted by benign lymphoproliferative disease, which may present in the respiratory system as tonsillar/adenoidal enlargement, mediastinal lymphadenopathy, or mucosal nodular lymphoid hyperplasia, potentially causing airways obstruction and compounding the infection phenotype. Treatment with rapamycin and PI3Kδ inhibitors has been reported to be of benefit in benign lymphoproliferation, but hematopoietic stem cell transplantation (ideally undertaken before permanent airway damage is established) remains the only curative treatment for APDS.

Transient activation of the PI3K/Akt pathway promotes Newcastle disease virus replication and enhances anti-apoptotic signaling responses

Viral infection activates a host's cellular phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, which is involved in cell differentiation, growth, survival, and apoptosis. To elucidate molecular mechanisms in the pathogenesis of Newcastle disease virus (NDV), we demonstrated that NDV transiently activates the PI3K/Akt pathway in chicken cells at an early phase of infection. Its activation was observed as early as 15 min post-infection and gradually weakened after 24 h. Incubating cells with a PI3K inhibitor, LY294002 or wortmannin, prior to NDV infection decreased NDV progeny yields and suppressed Akt phosphorylation at early times post-infection. Akt activation is triggered by NDV-GM or NDV-F48E9 and is abolished by methyl β-cyclodextrin and chlorpromazine. Treatment following NDV-La Sota infection had no obvious effect. However, inhibiting PI3K activation promoted apoptotic responses during an early stage of NDV infection. The pan caspase inhibitor ZVAD-FMK mitigated the reduction in Akt phosphorylation by inhibiting PI3K activation, which indicates the signaling pathway promotes cell survival and, in turn, facilitates viral replication. By suppressing premature apoptosis upon NDV infection, the PI3K/Akt pathway enhances the anti-apoptotic response.

Myocarditis

Viral myocarditis remains a prominent infectious-inflammatory disease for patients throughout the lifespan. The condition presents several challenges including varied modes of clinical presentation, a range of timepoints when patients come to attention, a diversity of approaches to diagnosis, a spectrum of clinical courses, and unsettled perspectives on therapeutics in different patient settings and in the face of different viral pathogens. In this review, we examine current knowledge about viral heart disease and especially provide information on evolving understanding of mechanisms of disease and efforts by investigators to identify and evaluate potential therapeutic avenues for intervention.

Oncolytic virotherapy for urological cancers

Oncolytic virotherapy is a cancer treatment in which replication-competent viruses are used that specifically infect, replicate in and lyse malignant tumour cells, while minimizing harm to normal cells. Anecdotal evidence of the effectiveness of this strategy has existed since the late nineteenth century, but advances and innovations in biotechnological methods in the 1980s and 1990s led to a renewed interest in this type of therapy. Multiple clinical trials investigating the use of agents constructed from a wide range of viruses have since been performed, and several of these enrolled patients with urological malignancies. Data from these clinical trials and from preclinical studies revealed a number of challenges to the effectiveness of oncolytic virotherapy that have prompted the development of further sophisticated strategies. Urological cancers have a range of distinctive features, such as specific genetic mutations and cell surface markers, which enable improving both effectiveness and safety of oncolytic virus treatments. The strategies employed in creating advanced oncolytic agents include alteration of the virus tropism, regulating transcription and translation of viral genes, combination with chemotherapy, radiotherapy or gene therapy, arming viruses with factors that stimulate the immune response against tumour cells and delivery technologies to ensure that the viral agent reaches its target tissue.

Hsp70-1: upregulation via selective phosphorylation of heat shock factor 1 during coxsackieviral infection and promotion of viral replication via the AU-rich element

Coxsackievirus B3 (CVB3) is the primary pathogen of viral myocarditis. Upon infection, CVB3 exploits the host cellular machineries, such as chaperone proteins, to benefit its own infection cycles. Inducible heat shock 70-kDa proteins (Hsp70s) are chaperone proteins induced by various cellular stress conditions. The internal ribosomal entry site (IRES) within Hsp70 mRNA allows Hsp70 to be translated cap-independently during CVB3 infection when global cap-dependent translation is compromised. The Hsp70 protein family contains two major members, Hsp70-1 and Hsp70-2. This study showed that Hsp70-1, but not Hsp70-2, was upregulated during CVB3 infection both in vitro and in vivo. Then a novel mechanism of Hsp70-1 induction was revealed in which CaMKIIγ is activated by CVB3 replication and leads to phosphorylation of heat shock factor 1 (HSF1) specifically at Serine 230, which enhances Hsp70-1 transcription. Meanwhile, phosphorylation of Ser230 induces translocation of HSF1 from the cytoplasm to nucleus, thus blocking the ERK1/2-mediated phosphorylation of HSF1 at Ser307, a negative regulatory process of Hsp70 transcription, further contributing to Hsp70-1 upregulation. Finally, we demonstrated that Hsp70-1 upregulation, in turn, stabilizes CVB3 genome via the AU-rich element (ARE) harbored in the 3' untranslated region of CVB3 genomic RNA.

Emodin inhibits coxsackievirus B3 replication via multiple signalling cascades leading to suppression of translation

CVB3 (coxsackievirus 3) is a primary causal agent of viral myocarditis. Emodin is a natural compound isolated from certain plant roots. In the present study, we found that emodin inhibited CVB3 replication in vitro and in mice, and now we report an unrecognized mechanism by which emodin inhibits CVB3 replication through suppression of viral protein translation via multiple pathways. On one hand, emodin treatment inhibited Akt/mTOR (mammalian target of rapamycin) signalling and activated 4EBP1 (eukaryotic initiation factor 4R-binding protein 1), leading to suppression of translation initiation of ribosomal protein L32 encoded by a 5'-TOP (terminal oligopyrimidine) mRNA. On the other hand, emodin treatment differentially regulated multiple signal cascades, including Akt/mTORC1/p70(S6K) (p70 S6 kinase), ERK1/2 (extracellular-signal-regulated kinase 1/2)/p90(RSK) (p90 ribosomal S6 kinase) and Ca(2+)/calmodulin, leading to activation of eEF2K (eukaryotic elongation factor 2 kinase) and subsequent inactivation of eEF2 (eukaryotic elongation factor 2), resulting in inhibition of CVB3 VP1 (viral protein 1) synthesis. These data imply that eEF2K is a major factor mediating cross-talk of different arms of signalling cascades in this signal network. This notion was verified by either overexpressing eEF2K or treating the cells with siRNAs or eEF2K inhibitor A484954. We showed further that the emodin-induced decrease in p70(S6K) phosphorylation plays a dominant positive role in activation of eEF2K and in turn in conferring the antiviral effect of emodin. This finding was further solidified by expressing constitutively active and dominant-negative Akt. Collectively, our data reveal that emodin inhibits viral replication through impairing translational machinery and suppression of viral translation elongation.

Panax Notoginseng Saponins Ameliorates Coxsackievirus B3-Induced Myocarditis by Activating the Cystathionine-γ-Lyase/Hydrogen Sulfide Pathway

This study is to determine the therapeutic effects of Panax notoginseng saponins (PNSs) on coxsackievirus B3 (CVB3)-induced myocarditis, and whether cystathionine-γ-lyase (CSE)/hydrogen sulfide (H2S) pathway is involved. Mouse model of myocarditis was induced by CVB3 infection, and the mice were subjected to vehicle (saline) or drug treatments (sodium bisulfide (NaHS), propargylglycine (PAG), or PNSs). The results showed that there were inflammatory cell infiltrations, interstitial edemas, and elevated inflammatory cytokines, in CVB3-induced myocarditis. PAG administration increased, whereas NaHS treatment decreased the severity of the myocarditis. PNS treatment dramatically alleviated these myocardial injuries and decreased the viral messenger RNA (mRNA) expression by the enhanced expression of CSE/H2S pathway. Moreover, the therapeutic effects of PNSs on myocarditis were stronger than those of NaHS. Finally, the effect of PNSs on CSE/H2S pathway and cardiac cell protection were verified in cultured cardiac cells. PNSs may be a promising medication for viral myocarditis therapy.

Recent progress in understanding coxsackievirus replication, dissemination, and pathogenesis

Coxsackieviruses (CVs) are relatively common viruses associated with a number of serious human diseases, including myocarditis and meningo-encephalitis. These viruses are considered cytolytic yet can persist for extended periods of time within certain host tissues requiring evasion from the host immune response and a greatly reduced rate of replication. A member of Picornaviridae family, CVs have been historically considered non-enveloped viruses - although recent evidence suggest that CV and other picornaviruses hijack host membranes and acquire an envelope. Acquisition of an envelope might provide distinct benefits to CV virions, such as resistance to neutralizing antibodies and efficient nonlytic viral spread. CV exhibits a unique tropism for progenitor cells in the host which may help to explain the susceptibility of the young host to infection and the establishment of chronic disease in adults. CVs have also been shown to exploit autophagy to maximize viral replication and assist in unconventional release from target cells. In this article, we review recent progress in clarifying virus replication and dissemination within the host cell, identifying determinants of tropism, and defining strategies utilized by the virus to evade the host immune response. Also, we will highlight unanswered questions and provide future perspectives regarding the potential mechanisms of CV pathogenesis.

Activation of AMPK restricts coxsackievirus B3 replication by inhibiting lipid accumulation

Coxsackievirus B3 (CVB3) is the major pathogen of human viral myocarditis. CVB3 has been found to manipulate and modify the cellular lipid metabolism for viral replication. The cellular AMP-activated protein kinase (AMPK) is a key regulator of multiple metabolic pathways, including lipid metabolism. Here we explore the potential roles AMPK plays in CVB3 infection. We found that AMPK is activated by the viral replication during CVB3 infection in Hela cells and primary myocardial cells. RNA interference mediated inhibition of AMPK could increase the CVB3 replication in cells, indicating that AMPK contributed to restricting the viral replication. Next, we showed that CVB3 replication could be inhibited by several different pharmacological AMPK activators including metformin, A769662 and AICAR. And the constitutively active AMPK mutant (CA-AMPK) could also inhibit the CVB3 replication. Furthermore, we found that CVB3 infection increased the cellular lipid levels and showed that the AMPK agonist AICAR both restricted CVB3 replication and reduced lipid accumulation through inhibiting the lipid synthesis associated gene expression. We further found that CVB3 infection would also induce AMPK activated in vivo. The AMPK agonist metformin, which has been widely used in diabetes therapy, could decrease the viral replication and further protect the mice from myocardial histological and functional changes in CVB3 induced myocarditis, and improve the survival rate of infected mice. Lastly, it was demonstrated that the AICAR-mediated restriction of viral replication could be rescued partially by exogenous palmitate, the first product of fatty acid biosynthesis, demonstrating that AMPK activation restricted CVB3 infection through its inhibition of lipid synthesis. Taken together, these data in the present study suggest a model in which AMPK is activated by CVB3 infection and restricts viral replication by inhibiting the cellular lipid accumulation, and inform a potential novel therapeutic strategy for CVB3-associated diseases.

Coxsackievirus B3 replication and pathogenesis

ABSTRACT 

Viruses such as coxsackievirus B3 (CVB3) are entirely host cell-dependent parasites. Indeed, they must cleverly exploit various compartments of host cells to complete their life cycle, and consequently launch disease. Evolution has equipped this pico-rna-virus, CVB3, to use different strategies, including CVB3-induced direct damage to host cells followed by a host inflammatory response to CVB3 infection, and cell death to super-additively promote target organ tissue injury, and dysfunction. In this update, the patho-stratagems of CVB3 are explored from molecular, and systems-level approaches. In summarizing recent developments in this field, we focus particularly on mechanisms by which CVB3 can harness different host cell processes including kinases, host cell-killing and cell-eating machineries, matrix metalloproteinases and miRNAs to promote disease.

Mapping of a quantitative trait locus controlling susceptibility to Coxsackievirus B3-induced viral hepatitis

The pathogenesis of coxsackieviral infection is a multifactorial process involving host genetics, viral genetics and the environment in which they interact. We have used a mouse model of Coxsackievirus B3 infection to characterize the contribution of host genetics to infection survival and to viral hepatitis. Twenty-five AcB/BcA recombinant congenic mouse strains were screened. One, BcA86, was found to be particularly susceptible to early mortality; 100% of BcA86 mice died by day 6 compared with 0% of B6 mice (P=0.0012). This increased mortality was accompanied by an increased hepatic necrosis as measured by serum alanine aminotransferase (ALT) levels (19547±10556 vs 769±109, P=0.0055). This occurred despite a predominantly resistant (C57BL/6) genetic background. Linkage analysis in a cohort (n=210) of (BcA86x C56Bl/10)F2 animals revealed a new locus on chromosome 13 (peak linkage 101.2 Mbp, lod 4.50 and P=0.003). This locus controlled serum ALT levels as early as 48 h following the infection, and led to an elevated expression of type I interferon. Another locus on chromosome 17 (peak linkage 57.2 Mbp) was significantly linked to heart viral titer (lod 3.4 and P=0.046). These results provide new evidence for the presence of genetic loci contributing to the susceptibility of mice to viral hepatitis.

Ubiquitin-Like Protein ISG15 (Interferon-Stimulated Gene of 15 kDa) in Host Defense Against Heart Failure in a Mouse Model of Virus-Induced Cardiomyopathy

Background—

Common causative agents in the development of inflammatory cardiomyopathy include cardiotropic viruses such as coxsackievirus B3 (CVB3). Here, we investigated the role of the ubiquitin-like modifier interferon-stimulated gene of 15 kDa (ISG15) in the pathogenesis of viral cardiomyopathy.

Methods and Results—

In CVB3-infected mice, the absence of protein modification with ISG15 was accompanied by a profound exacerbation of myocarditis and by a significant increase in mortality and heart failure. We found that ISG15 in cardiomyocytes contributed significantly to the suppression of viral replication. In the absence of an intact ISG15 system, virus titers were markedly elevated by postinfection day 8, and viral RNA persisted in ISG15 −/− mice at postinfection day 28. Ablation of the ISG15 protein modification system in CVB3 infection predisposed mice to long-term disease with deposition of collagen fibers, all leading to inflammatory cardiomyopathy. We found that ISG15 acts as part of the intrinsic immunity in cardiomyocytes and detected no significant effects of ISG15 modification on the cellular immune response. ISG15 modification of CVB3 2A protease counterbalanced CVB3-induced cleavage of the host cell eukaryotic initiation factor of translation eIF4G in cardiomyocytes, thereby counterbalancing the shutoff of host cell translation in CVB3 infection. We demonstrate that ISG15 suppressed infectious virus yield in human cardiac myocytes and the induction of ISG15 in patients with viral cardiomyopathy.

Conclusions—

The ISG15 conjugation system represents a critical innate response mechanism in cardiomyocytes to fight the battle against invading pathogens, limiting inflammatory cardiomyopathy, heart failure, and death. Interference with the ISG15 system might be a novel therapeutic approach in viral cardiomyopathy.

ORI2 inhibits coxsackievirus replication and myocardial inflammation in experimental murine myocarditis

We purified ORI2 [3-(3,4-dihydroxyphenyl)acrylic acid 1-(3,4-dihydroxyphenyl)-2-methoxycarbonylethyl ester] from an extract of the plant Isodon excisus. We tested the antiviral effect of ORI2 in a coxsackievirus-induced myocarditis model. Coxsackievirus B3 (CVB3) is a common cause of myocarditis and dilated cardiomyopathy. Activation of extracellular signal-regulated kinase (ERK) and Akt signaling in virus-infected cells is essential for CVB3 replication. Antiviral compounds were screened by HeLa cell survival assay. Several purified natural compounds were added to HeLa cells cultured in 96-well plates for 30 min after 1 multiplicity of infection (m.o.i) CVB3 infection. ORI2 significantly improved HeLa cell survival in a dose-dependent manner. For in vivo studies, BALB/c mice (n=20) were infected with CVB3, then 10 of the mice were treated by daily intraperitoneal injections of ORI2 (100 mM) for 3 consecutive days. ORI2 treatment significantly improved early survival in the treated mice compared to untreated mice (85% vs. 50%, respectively). Organ virus titers and myocardial damage were significantly lower in the ORI2-treated mice than in untreated mice. These results demonstrate that ORI2, delivered by intraperitoneal injection after CVB3 infection, has a significant antiviral effect by markedly inhibiting virus replication, resulting in a decrease in organ virus titer and myocardial damage. ORI2 may be developed as a potential therapeutic agent for the treatment of CVB3 infections.

Death waits for no man--does it wait for a virus? How enteroviruses induce and control cell death

Enteroviruses (EVs) are the most common human viral pathogens. They cause a variety of pathologies, including myocarditis and meningoencephalopathies, and have been linked to the onset of type I diabetes. These pathologies result from the death of cells in the myocardium, central nervous system, and pancreas, respectively. Understanding the role of EVs in inducing cell death is crucial to understanding the etiologies of these diverse pathologies. EVs both induce and delay host cell death, and their exquisite control of this balance is crucial for their success as human viral pathogens. Thus, EVs are tightly involved with cell death signaling pathways and interact with host cell signaling at multiple points. Here, we review the literature detailing the mechanisms of EV-induced cell death. We discuss the mechanisms by which EVs induce cell death, the signaling pathways involved in these pathways, and the strategies by which EVs antagonize cell death pathways. We also discuss the role of cell death in both the resulting pathology in the host and in the facilitation of viral spread.

Beta interferon regulation of glucose metabolism is PI3K/Akt dependent and important for antiviral activity against coxsackievirus B3

An effective type I interferon (IFN)-mediated immune response requires the rapid expression of antiviral proteins that are necessary to inhibit viral replication and virus spread. We provide evidence that IFN-β regulates metabolic events important for the induction of a rapid antiviral response: IFN-β decreases the phosphorylation of AMP-activated protein kinase (AMPK), coincident with an increase in intracellular ATP. Our studies reveal a biphasic IFN-β-inducible uptake of glucose by cells, mediated by phosphatidylinositol 3-kinase (PI3K)/Akt, and IFN-β-inducible regulation of GLUT4 translocation to the cell surface. Additionally, we provide evidence that IFN-β-regulated glycolytic metabolism is important for the acute induction of an antiviral response during infection with coxsackievirus B3 (CVB3). Last, we demonstrate that the antidiabetic drug metformin enhances the antiviral potency of IFN-β against CVB3 both in vitro and in vivo. Taken together, these findings highlight an important role for IFN-β in modulating glucose metabolism during a virus infection and suggest that the use of metformin in combination with IFN-β during acute virus infection may result in enhanced antiviral responses.

IMPORTANCE

Type I interferons (IFN) are critical effectors of an antiviral response. These studies describe for the first time a role for IFN-β in regulating metabolism--glucose uptake and ATP production--to meet the energy requirements of a robust cellular antiviral response. Our data suggest that IFN-β regulates glucose metabolism mediated by signaling effectors similarly to activation by insulin. Interference with IFN-β-inducible glucose metabolism diminishes the antiviral response, whereas treatment with metformin, a drug that increases insulin sensitivity, enhances the antiviral potency of IFN-β.

From scourge to cure: tumour-selective viral pathogenesis as a new strategy against cancer

Tumour mutations corrupt cellular pathways, and accumulate to disrupt, dysregulate, and ultimately avoid mechanisms of cellular control. Yet the very changes that tumour cells undergo to secure their own growth success also render them susceptible to viral infection. Enhanced availability of surface receptors, disruption of antiviral sensing, elevated metabolic activity, disengagement of cell cycle controls, hyperactivation of mitogenic pathways, and apoptotic avoidance all render the malignant cell environment highly supportive to viral replication. The therapeutic use of oncolytic viruses (OVs) with a natural tropism for infecting and subsequently lysing tumour cells is a rapidly progressing area of cancer research. While many OVs exhibit an inherent degree of tropism for transformed cells, this can be further promoted through pharmacological interventions and/or the introduction of viral mutations that generate recombinant oncolytic viruses adapted to successfully replicate only in a malignant cellular environment. Such adaptations that augment OV tumour selectivity are already improving the therapeutic outlook for cancer, and there remains tremendous untapped potential for further innovation.

MiR-126 promotes coxsackievirus replication by mediating cross-talk of ERK1/2 and Wnt/β-catenin signal pathways

Coxsackievirus B3 (CVB3) is one of the most prevalent causes of viral myocarditis and is associated with many other pathological conditions. CVB3 replication relies on host cellular machineries and causes direct damage to host cells. MicroRNAs have been found to regulate viral infections but their roles in CVB3 infection are still poorly understood. Here we describe a novel mechanism by which miR-126 regulates two signal pathways essential for CVB3 replication. We found that CVB3-induced ERK1/2 activation triggered the phosphorylation of ETS-1 and ETS-2 transcription factors, which induced miR-126 upregulation. By using both microRNA mimics and inhibitors, we proved that the upregulated miR-126 suppressed sprouty-related, EVH1 domain containing 1 (SPRED1) and in turn enhanced ERK1/2 activation. This positive feedback loop of ERK1/2-miR-126-ERK1/2 promoted CVB3 replication. Meanwhile, miR-126 expression stimulated GSK-3β activity and induced degradation of β-catenin through suppressing LRP6 and WRCH1, two newly identified targets in the Wnt/β-catenin pathway, which sensitized the cells to virus-induced cell death and increased viral progeny release to initiate new infections. Our results demonstrate that upregulated miR-126 upon CVB3 infection targets SPRED1, LRP6, and WRCH1 genes, mediating cross-talk between ERK1/2 and Wnt/β-catenin pathways, and thus promoting viral replication and contributes to the viral cytopathogenicity.

P58(IPK) inhibits coxsackievirus-induced apoptosis via the PI3K/Akt pathway requiring activation of ATF6a and subsequent upregulation of mitofusin 2

Previously we found that prolonged endoplasmic reticulum (ER) stress caused by coxsackievirus B3 (CVB3) infection led to p58(IPK) downregulation and subsequent cell apoptosis. This finding implies that p58(IPK) expression benefits cell survival and counteracts CVB3-induced apoptosis. In testing this hypothesis, we first found that PI3K/Akt survival pathway is more sensitive than ERK1/2 in response to p58(IPK) expression. This finding was further verified by silencing p58(IPK) with specific siRNAs, which led to the significant suppression of phosphorylation of Akt (p-Akt) but not ERK1/2. Further, using CVB3-infected cell line expressing dominant negative ATF6a (DN-ATF6a), we found that expression of p58(IPK) and p-Akt was significantly reduced, which led to the decreased cell viability. However, when the DN-ATF6a cells were transiently transfected with p58(IPK) , an opposite result was obtained. Finally, by CVB3 infection of cells stably expressing p58(IPK) , we found that CVB3-induced mitochondria-mediated apoptosis was suppressed, which was evidenced by the reduced cytochrome c release and upregulation of the mitochondrial membrane protein mitofusin 2. However, silencing p58(IPK) with either specific siRNAs or DN-ATF6a sensitized cells to CVB3-induced apoptosis. These results suggest that p58(IPK) suppresses CVB3-induced apoptosis through selective activation of PI3K/Akt pathway that requires activation of ATF6a and subsequently upregulates mitofusin 2.

ViralPhos: incorporating a recursively statistical method to predict phosphorylation sites on virus proteins

Background

The phosphorylation of virus proteins by host kinases is linked to viral replication. This leads to an inhibition of normal host-cell functions. Further elucidation of phosphorylation in virus proteins is required in order to aid in drug design and treatment. However, only a few studies have investigated substrate motifs in identifying virus phosphorylation sites. Additionally, existing bioinformatics tool do not consider potential host kinases that may initiate the phosphorylation of a virus protein.

Results

329 experimentally verified phosphorylation fragments on 111 virus proteins were collected from virPTM. These were clustered into subgroups of significantly conserved motifs using a recursively statistical method. Two-layered Support Vector Machines (SVMs) were then applied to train a predictive model for the identified substrate motifs. The SVM models were evaluated using a five-fold cross validation which yields an average accuracy of 0.86 for serine, and 0.81 for threonine. Furthermore, the proposed method is shown to perform at par with three other phosphorylation site prediction tools: PPSP, KinasePhos 2.0 and GPS 2.1.

Conclusion

In this study, we propose a computational method, ViralPhos, which aims to investigate virus substrate site motifs and identify potential phosphorylation sites on virus proteins. We identified informative substrate motifs that matched with several well-studied kinase groups as potential catalytic kinases for virus protein substrates. The identified substrate motifs were further exploited to identify potential virus phosphorylation sites. The proposed method is shown to be capable of predicting virus phosphorylation sites and has been implemented as a web server http://csb.cse.yzu.edu.tw/ViralPhos/.

LY294002 and Rapamycin promote coxsackievirus-induced cytopathic effect and apoptosis via inhibition of PI3K/AKT/mTOR signaling pathway

Coxsackievirus B3 (CVB3) is a common human pathogen for acute myocarditis, pancreatitis, non-septic meningitis, and encephalitis; it induces a direct cytopathic effect (CPE) and apoptosis on infected cells. The Phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT/PKB)/mammalian target of Rapamycin (mTOR) signaling pathway regulates several cellular processes and it is one of the most important pathways in human networks. However, the effect and mechanism of PI3K/AKT/mTOR signaling pathway in CVB3 infected cells are poorly understood. In this study, we demonstrate that inhibition of PI3K/AKT/mTOR signaling pathway increased CVB3-induced CPE and apoptosis in HeLa cells. The activity of downstream targets of PI3K and mTOR is attenuated after CVB3 infection and inhibitors of PI3K and mTOR made their activity to decrease more significantly. We further show that LY294002 and Rapamycin, the inhibitor of PI3K and mTOR respectively, promote CVB3-induced CPE and apoptosis. Taken together, these data illustrate a new and imperative role for PI3K/AKT/mTOR signaling in CVB3 infection in HeLa cells and suggest an useful approach for the therapy of CVB3 infection.

Overexpression of 4EBP1, p70S6K, Akt1 or Akt2 differentially promotes Coxsackievirus B3-induced apoptosis in HeLa cells

Our previous studies have shown that the inhibition of phosphatidylinositol 3-kinase (PI3K) or mTOR complex 1 can obviously promote the Coxsackievirus B3 (CVB3)-induced apoptosis of HeLa cells by regulating the expression of proapoptotic factors. To further illustrate it, Homo sapiens eIF4E-binding protein 1 (4EBP1), p70S6 kinase (p70S6K), Akt1 and Akt2 were transfected to HeLa cells, respectively. And then, we established the stable transfected cell lines. Next, after CVB3 infection, apoptosis in different groups was determined by flow cytometry; the expressions of Bim, Bax, caspase-9 and caspase-3 were examined by real-time fluorescence quantitative PCR and western blot analysis; the expression of CVB3 mRNA and viral capsid protein VP1 were also analyzed by real-time fluorescence quantitative PCR, western blot analysis and immunofluorescence, respectively. At the meantime, CVB3 replication was observed by transmission electron microscope. We found that CVB3-induced cytopathic effect and apoptosis in transfected groups were more obvious than that in controls. Unexpectedly, apoptosis rate in Akt1 group was higher than others at the early stage after viral infection and decreased with the viral-infected time increasing, which was opposite to other groups. Compared with controls, the expression of CVB3 mRNA was increased at 3, 6, 12 and 24 h postinfection (p. i.) in all groups. At the meantime, VP1 expression in 4EBP1 group was higher than control during the process of infection, while the expressions in the other groups were change dynamically. Moreover, overexpression of 4EBP1 did not affect the mRNA expressions of Bim, Bax, caspase-9 and caspase-3; while protein expressions of Bim and Bax were decreased, the self-cleavages of caspase-9 and caspase-3 were stimulated. Meanwhile, overexpression of p70S6K blocked the CVB3-induced Bim, Bax and caspase-9 expressions but promoted the self-cleavage of caspase-9. In the Akt1 group, it is noteworthy that the expressions of Bim protein were higher than controls at 3 and 6 h p. i. but lower at 24 h p. i., and the expression of Bax protein were higher at 6 and 24 h p. i., while their mRNA expressions were all decreased. Furthermore, overexpression of Akt1 stimulated the procaspase-9 and procaspase-3 expression but blocked their self-cleavages. Overexpression of Akt2, however, had little effect on Bim, Bax and caspase-3, while prevented caspase-9 from self-cleavage at the late stage of CVB3 infection. As stated above, our results demonstrated that overexpression of 4EBP1, p70S6K, Akt1 or Akt2 could promote the CVB3-induced apoptosis in diverse degree via different mediating ways in viral replication and proapoptotic factors in BcL-2 and caspase families. As 4EBP1, p70S6K and Akt are the important substrates of PI3K and mammalian target of rapamycin (mTOR), we further illustrated the role of PI3K/Akt/mTOR signaling pathway in the process of CVB3-induced apoptosis.

The AKT genes and their roles in various disorders

AKT (AK mouse plus Transforming or Thymoma) is a common oncogene expressed in most tissues. Both AKT2 and AKT3, although important, have more limited distributions. The regulation of all three genes depends on two receptors-a receptor tyrosine kinase with a growth factor ligand, and a G protein coupled receptor, also with a ligand together with an explanation of how their downsteam components function. AKT2 is amplified or overexpressed in cancer with a higher frequency than those found with AKT1. AKT1 is cardioprotective to the heart by supporting its physiological growth and function. AKT2 is closely linked to Type II diabetes and the implications of various types of mutations are discussed. Various AKT3 mutations are important in neurological disorders, such as microcephaly, hemimegalencephaly, and megalencephaly syndromes. Finally, a reduced level of AKT1 in the frontal cortex has been found during post-mortem brain studies of schizophrenic patients in the populations of many countries.

Study of vaccinia and cowpox viruses' replication in Rac1-N17 dominant-negative cells

Interfering with cellular signal transduction pathways is a common strategy used by many viruses to create a propitious intracellular environment for an efficient replication. Our group has been studying cellular signalling pathways activated by the orthopoxviruses Vaccinia (VACV) and Cowpox (CPXV) and their significance to viral replication. In the present study our aim was to investigate whether the GTPase Rac1 was an upstream signal that led to the activation of MEK/ERK1/2, JNK1/2 or Akt pathways upon VACV or CPXV' infections. Therefore, we generated stable murine fibroblasts exhibiting negative dominance to Rac1-N17 to evaluate viral growth and the phosphorylation status of ERK1/2, JNK1/2 and Akt. Our results demonstrated that VACV replication, but not CPXV, was affected in dominant-negative (DN) Rac1-N17 cell lines in which viral yield was reduced in about 10-fold. Viral late gene expression, but not early, was also reduced. Furthermore, our data showed that Akt phosphorylation was diminished upon VACV infection in DN Rac1-N17 cells, suggesting that Rac1 participates in the phosphoinositide-3 kinase pathway leading to the activation of Akt. In conclusion, our results indicate that while Rac1 indeed plays a role in VACV biology, perhaps another GTPase may be involved in CPXV replication.

Study of vaccinia and cowpox viruses' replication in Rac1-N17 dominant-negative cells

Interfering with cellular signal transduction pathways is a common strategy used by many viruses to create a propitious intracellular environment for an efficient replication. Our group has been studying cellular signalling pathways activated by the orthopoxviruses Vaccinia (VACV) and Cowpox (CPXV) and their significance to viral replication. In the present study our aim was to investigate whether the GTPase Rac1 was an upstream signal that led to the activation of MEK/ERK1/2, JNK1/2 or Akt pathways upon VACV or CPXV' infections. Therefore, we generated stable murine fibroblasts exhibiting negative dominance to Rac1-N17 to evaluate viral growth and the phosphorylation status of ERK1/2, JNK1/2 and Akt. Our results demonstrated that VACV replication, but not CPXV, was affected in dominant-negative (DN) Rac1-N17 cell lines in which viral yield was reduced in about 10-fold. Viral late gene expression, but not early, was also reduced. Furthermore, our data showed that Akt phosphorylation was diminished upon VACV infection in DN Rac1-N17 cells, suggesting that Rac1 participates in the phosphoinositide-3 kinase pathway leading to the activation of Akt. In conclusion, our results indicate that while Rac1 indeed plays a role in VACV biology, perhaps another GTPase may be involved in CPXV replication.