Influenza A virus induces interleukin-27 through cyclooxygenase-2 and protein kinase A signaling

In Vitro and In Silico Studies on the Anti-H1N1 Activity of Bioactive Compounds from Marine-Derived Streptomyces ardesiacus

This study explores the potential anti-H1N1 Influenza A activity of bioactive compounds extracted from Streptomyces ardesiacus, a marine-derived microorganism known for producing diverse secondary metabolites. Four major compounds-1-acetyl-β-carboline, 1H-indole-3-carbaldehyde, anthranilic acid, and indole-3-carboxylic acid-were isolated and characterized through NMR. Among these, the identified structure of 1-acetyl-β-carboline showed the highest IC50 effect, with a dose of 9.71 μg/mL in anti-influenza assays. Using network pharmacology and molecular docking analyses, the interactions of these compounds with key proteins involved in H1N1 pathogenesis were examined. Protein-protein interaction (PPI) networks and Gene Ontology enrichment analysis revealed CDC25B, PARP1, and PTGS2 as key targets, associating these compounds with pathways related to catalytic activity, inflammation, and cell cycle regulation. The molecular docking results demonstrated that 1-acetyl-β-carboline exhibited binding affinities comparable to Tamiflu, the positive control drug, with LibDock scores of 81.89, 77.49, and 89.21 for CDC25B, PARP1, and PTGS2, respectively, compared to Tamiflu's scores of 84.34, 86.13, and 91.29. These findings highlight the potential of the active compound 1-acetyl-β-carboline from S. ardesiacus as a novel anti-influenza agent, offering insights into their molecular mechanisms of action. The results support further in vitro and in vivo studies to validate the observed inhibitory mechanisms and therapeutic applications against H1N1 Influenza A.

Impact of single nucleotide polymorphism of IL-27P28 rs153109 and IFITM3 rs12252 on susceptibility and severity of COVID-19 in Egyptian patients: a case control study

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes Coronavirus disease 2019 (COVID-19), which is a huge global health threat. Interleukin27 (IL-27) gene is a cytokine that produces antiviral proteins in an IFN-independent manner and stimulates both pro- and anti-inflammatory responses. Interferon induced transmembrane protein 3 (IFITM3) inhibits SARS-CoV2 infection by blocking SARSCoV-2 spike proteins which facilitate viral entrance and cell-to-cell fusion. The association between genetic variants and COVID-19 in Egyptians is still unclear. Hence, we sought to investigate the impact of the single nucleotide polymorphism of IL-27P28 rs153109 and IFITM3 rs12252 on the susceptibility and severity of SARS-CoV-2 in Egyptian patients.

METHODS

Our study included 242 SARS-CoV-2 patients were recruited from Main University Hospital, Alexandria University, Egypt, and 187 healthy controls. We subdivided the patient group into two subgroups: group A comprised mild/moderate cases (N = 42) (17.4%), and group B included severe/critical cases (N = 200) (82.6%). Genomic DNA was extracted from blood samples using the QIAamp DNA Blood Mini kit, then the PCR products of IL27 and IFITM3 were cut by FastDigest XhoI and MScI, respectively, for detection of SNPs of IL-27P28 rs153109 (-964A/G) and IFITM3 rs12252 (T>C).

RESULTS

The present study found a significant association between IL27 rs153109 (-964A/G) and SARS-CoV-2 infection susceptibility after adjusting for the risk factor (advanced age), IL27 rs153109 (-964A/G) AG genotype (OR = 2.791, 95% CI: 1.237-6.295, P = 0.013), AA genotype (OR = 2.385, 95% CI: 1.075-5.291, P = 0.033), and (AG+AA vs. GG) genotypes (OR = 2.558, 95% CI: 1.186-5.517, P = 0.017). On the other hand, the IFITM3 rs12252(T>C) CT genotype (OR = 1.419, 95% CI: 0.843-2.391, P = 0.188), CC genotype (OR = 2.132, 95% CI: 0.436-10.415, P = 0.350), and (C/T+C/C vs. TT) genotypes (OR = 1.466, 95% CI: 0.884-2.432, P = 0.138) did not show a statistically significant association with either susceptibility or the severity of SARS-CoV-2.

CONCLUSION

IL27P28 rs153109 AG and AA genotypes of IL27 may be associated with the susceptibility of SARS-CoV-2 infection but not the severity. Concerning the IFITM3 rs12252 SNP, we could not confirm its influence on either susceptibility or the severity of SARS-CoV-2 in this Egyptian population.

IL-27 expression regulation and its effects on adaptive immunity against viruses

IL-27, a member of the IL-6/IL-12 cytokine superfamily, is primarily secreted by antigen presenting cells, specifically by dendric cells, macrophages and B cells. IL-27 has antiviral activities and modulates both innate and adaptive immune responses against viruses. The role of IL-27 in the setting of viral infections is not well defined and both pro-inflammatory and anti-inflammatory functions have been described. Here, we discuss the latest advancements in the role of IL-27 in several viral infection models of human disease. We highlight important aspects of IL-27 expression regulation, the critical cell sources at different stages of the infection and their impact in cell mediated immunity. Lastly, we discuss the need to better define the antiviral and modulatory (pro-inflammatory vs anti-inflammatory) properties of IL-27 in the context of human chronic viral infections.

Interleukin 27, like interferons, activates JAK-STAT signaling and promotes pro-inflammatory and antiviral states that interfere with dengue and chikungunya viruses replication in human macrophages

Interferons (IFNs) are a family of cytokines that activate the JAK-STAT signaling pathway to induce an antiviral state in cells. Interleukin 27 (IL-27) is a member of the IL-6 and/or IL-12 family that elicits both pro- and anti-inflammatory responses. Recent studies have reported that IL-27 also induces a robust antiviral response against diverse viruses, both in vitro and in vivo, suggesting that IFNs and IL-27 share many similarities at the functional level. However, it is still unknown how similar or different IFN- and IL-27-dependent signaling pathways are. To address this question, we conducted a comparative analysis of the transcriptomic profiles of human monocyte-derived macrophages (MDMs) exposed to IL-27 and those exposed to recombinant human IFN-α, IFN-γ, and IFN-λ. We utilized bioinformatics approaches to identify common differentially expressed genes between the different transcriptomes. To verify the accuracy of this approach, we used RT-qPCR, ELISA, flow cytometry, and microarrays data. We found that IFNs and IL-27 induce transcriptional changes in several genes, including those involved in JAK-STAT signaling, and induce shared pro-inflammatory and antiviral pathways in MDMs, leading to the common and unique expression of inflammatory factors and IFN-stimulated genes (ISGs)Importantly, the ability of IL-27 to induce those responses is independent of IFN induction and cellular lineage. Additionally, functional analysis demonstrated that like IFNs, IL-27-mediated response reduced chikungunya and dengue viruses replication in MDMs. In summary, IL-27 exhibits properties similar to those of all three types of human IFN, including the ability to stimulate a protective antiviral response. Given this similarity, we propose that IL-27 could be classified as a distinct type of IFN, possibly categorized as IFN-pi (IFN-π), the type V IFN (IFN-V).

Role of IL-27 in HSV-1-Induced Herpetic Stromal Keratitis

Herpetic stromal keratitis (HSK) is a painful and vision-impairing disease caused by recurrent HSV-1 infection of the cornea. The virus replication in the corneal epithelium and associated inflammation play a dominant role in HSK progression. Current HSK treatments targeting inflammation or virus replication are partially effective and promote HSV-1 latency, and long-term use can cause side effects. Thus, understanding molecular and cellular events that control HSV-1 replication and inflammation is crucial for developing novel HSK therapies. In this study, we report that ocular HSV-1 infection induces the expression of IL-27, a pleiotropic immunoregulatory cytokine. Our data indicate that HSV-1 infection stimulates IL-27 production by macrophages. Using a primary corneal HSV-1 infection mouse model and IL-27 receptor knockout mice, we show that IL-27 plays a critical role in controlling HSV-1 shedding from the cornea, the optimum induction of effector CD4+ T cell responses, and limiting HSK progression. Using in vitro bone marrow-derived macrophages, we show that IL-27 plays an antiviral role by regulating macrophage-mediated HSV-1 killing, IFN-β production, and IFN-stimulated gene expression after HSV-1 infection. Furthermore, we report that IL-27 is critical for macrophage survival, Ag uptake, and the expression of costimulatory molecules involved in the optimum induction of effector T cell responses. Our results indicate that IL-27 promotes endogenous antiviral and anti-inflammatory responses and represents a promising target for suppressing HSK progression.

Antiviral response and immunopathogenesis of interleukin 27 in COVID-19

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with a high mortality rate. The clinical course is attributed to the severity of pneumonia and systemic complications. In COVID-19 patients and murine models of SARS-CoV-2 infection, the disease may be accompanied by excessive production of cytokines, leading to an accumulation of immune cells in affected organs such as lungs. Previous reports have shown that SARS-CoV-2 infection antagonizes interferon (IFN)-dependent antiviral response, thereby preventing the expression of IFN-stimulated genes (ISGs). Lower IFN levels have been linked to more-severe COVID-19. Interleukin 27 (IL27) is a heterodimeric cytokine composed of IL27p28 and EBI3 subunits, which induce both pro- and anti-inflammatory responses. Recently, we and others have reported that IL27 also induces a strong antiviral response in an IFN-independent manner. Here, we investigated transcription levels of both IL27 subunits in COVID-19 patients. The results show that SARS-CoV-2 infection modulates TLR1/2-MyD88 signaling in PBMCs and monocytes and induces NF-κB activation and expression of NF-κB-target genes that are dependent on a robust pro-inflammatory response, including EBI3; and activates IRF1 signaling which induces IL27p28 mRNA expression. The results suggest that IL27 induces a robust STAT1-dependent pro-inflammatory and antiviral response in an IFN-independent manner in COVID-derived PBMCs and monocytes as a function of a severe clinical course of COVID-19. Similar results were observed in macrophages stimulated with the SARS-CoV-2 spike protein. Thus, IL27 can trigger an antiviral response in the host, suggesting the possibility of novel therapeutics against SARS-CoV-2 infection in humans.

Artesunate inhibits PDE4 leading to intracellular cAMP accumulation, reduced ERK/MAPK signaling, and blockade of influenza A virus vRNP nuclear export

Influenza A viruses (IAV) have been a major cause of mortality. Given the potential for future deadly pandemics, effective drugs are needed for the treatment of severe influenzas, such as those caused by H5N1 IAV. The anti-malaria drugs artemisinin and its derivates, including artesunate (AS), have been reported to have broad antiviral activities. Here, we showed AS's antiviral activity against H5N1, H1N1, H3N2 and oseltamivir-resistant influenza A(H1N1)virus in vitro. Moreover, we showed that AS treatment significantly protected mice from lethal challenges with H1N1 and H5N1 IAV. Strikingly, the combination of AS and peramivir treatment significantly improved survival outcomes compared to their monotherapy with either AS or peramivir. Furthermore, we demonstrated mechanistically that AS affected the later stages of IAV replication and limited nuclear export of viral ribonucleoprotein (vRNP) complexes. In A549 cells, we demonstrated for the first time that AS treatment induced cAMP accumulation via inhibiting PDE4, and consequently reduced ERK phosphorylation and blocked IAV vRNP export, and thus suppressed IAV replication. These AS's effects were reversed by the pre-treatment with a cAMP inhibitor SQ22536. Our findings suggest that AS could serve as a novel IAV inhibitor by interfering vRNP nuclear export to prevent and treat IAV infection.

Potential of Interleukin (IL)-12 Group as Antivirals: Severe Viral Disease Prevention and Management

The interleukin (IL)-12 family consists of pro- and anti-inflammatory cytokines that are able to signal the activation of host antiviral immunity while preventing over-reactive immune reactions due to active virus replication and viral clearance. Amongst others, IL-12 and IL-23 are produced and released by innate immune cells such as monocytes and macrophages to signal the proliferation of T cells and release of effector cytokines, which subsequently activate host defence against virus infections. Interestingly, the dualities of IL-27 and -35 are evidently shown in the course of virus infections; they regulate the synthesis of cytokines and antiviral molecules, proliferation of T cells, and viral antigen presentation in order to maximize virus clearance by the host immune system. In terms of anti-inflammatory reactions, IL-27 signals the formation of regulatory T cells (Treg) which in turn secrete IL-35 to control the scale of inflammatory response that takes place during virus infections. Given the multitasking of the IL-12 family in regards to the elimination of virus infections, its potential in antiviral therapy is unequivocally important. Thus, this work aims to delve deeper into the antiviral actions of the IL-12 family and their applications in antiviral therapies.

Antiviral Activity of a Cyclic Pro-Pro-β3-HoPhe-Phe Tetrapeptide against HSV-1 and HAdV-5

The core of Cyclolinopeptide A (CLA, cyclo(LIILVPPFF)), responsible for its high immunosuppressive activity, contains a Pro-Pro-Phe-Phe sequence. A newly synthesized cyclic tetrapeptide, cyclo(Pro-Pro-β3-HoPhe-Phe) (denoted as 4B8M) bearing the active sequence of CLA, was recently shown to exhibit a wide array of anti-inflammatory properties in mouse models. In this investigation, we demonstrate that the peptide significantly inhibits the replication of human adenovirus C serotype 5 (HAdV-5) and Herpes simplex virus type-1 (HSV-1) in epithelial lung cell line A-549, applying Cidofovir and Acyclovir as reference drugs. Based on a previously established mechanism of its action, we propose that the peptide may inhibit virus replication by the induction of PGE2 acting via EP2/EP4 receptors in epithelial cells. In summary, we reveal a new, antiviral property of this anti-inflammatory peptide.

Antiviral Activities of Interleukin-27: A Partner for Interferons?

Emergence of new, pandemic-level viral threats has brought to the forefront the importance of viral immunology and continued improvement of antiviral therapies. Interleukin-27 (IL-27) is a pleiotropic cytokine that regulates both innate and adaptive immune responses. Accumulating evidence has revealed potent antiviral activities of IL-27 against numerous viruses, including HIV, influenza, HBV and more. IL-27 contributes to the immune response against viruses indirectly by increasing production of interferons (IFNs) which have various antiviral effects. Additionally, IL-27 can directly interfere with viral infection both by acting similarly to an IFN itself and by modulating the differentiation and function of various immune cells. This review discusses the IFN-dependent and IFN-independent antiviral mechanisms of IL-27 and highlights the potential of IL-27 as a therapeutic cytokine for viral infection.

Marek's Disease Virus Modulates T Cell Proliferation via Activation of Cyclooxygenase 2-Dependent Prostaglandin E2

Marek’s disease virus (MDV), an avian alphaherpesvirus, infects chickens, transforms CD4+ T cells, and induces immunosuppression early during infection. However, the exact mechanisms involved in MDV-induced immunosuppression are yet to be identified. Here, our results demonstrate that MDV infection in vitro and in vivo induces activation of cyclooxygenase-2 (COX-2) and production of prostaglandin E2 (PGE2). This exerts its inhibitory effects on T cell proliferation at day 21 post infection via PGE2 receptor 2 (EP2) and receptor 4 (EP4). Impairment of the MDV-induced T cell proliferation was associated with downregulation of IL-2 and transferrin uptake in a COX-2/PGE2 dependent manner in vitro. Interestingly, oral administration of a COX-2 inhibitor, meloxicam, during MDV infection inhibited COX-2 activation and rescued T cell proliferation at day 21 post infection. Taken together, our results reveal a novel mechanism that contributes to immunosuppression in the MDV-infected chickens.

Synergistic Effects of Toll-Like Receptor 1/2 and Toll-Like Receptor 3 Signaling Triggering Interleukin 27 Gene Expression in Chikungunya Virus-Infected Macrophages

Chikungunya virus (CHIKV) is the etiological agent of chikungunya fever (CHIKF), a self-limiting disease characterized by myalgia and severe acute or chronic arthralgia. CHIKF is associated with immunopathology and high levels of pro-inflammatory factors. CHIKV is known to have a wide range of tropism in human cell types, including keratinocytes, fibroblasts, endothelial cells, monocytes, and macrophages. Previously, we reported that CHIKV-infected monocytes-derived macrophages (MDMs) express high levels of interleukin 27 (IL27), a heterodimeric cytokine consisting of IL27p28 and EBI3 subunits, that triggers JAK-STAT signaling and promotes pro-inflammatory and antiviral response, in interferon (IFN)-independent manner. Based on the transcriptomic analysis, we now report that induction of IL27-dependent pro-inflammatory and antiviral response in CHIKV-infected MDMs relies on two signaling pathways: an early signal dependent on recognition of CHIKV-PAMPs by TLR1/2-MyD88 to activate NF-κB-complex that induces the expression of EBI3 mRNA; and second signaling dependent on the recognition of intermediates of CHIKV replication (such as dsRNA) by TLR3-TRIF, to activate IRF1 and the induction of IL27p28 mRNA expression. Both signaling pathways were required to produce a functional IL27 protein involved in the induction of ISGs, including antiviral proteins, cytokines, CC- and CXC- chemokines in an IFN-independent manner in MDMs. Furthermore, we reported that activation of TLR4 by LPS, both in human MDMs and murine BMDM, results in the induction of both subunits of IL27 that trigger strong IL27-dependent pro-inflammatory and antiviral response independent of IFNs signaling. Our findings are a significant contribution to the understanding of molecular and cellular mechanisms of CHIKV infection.

The impact of HCV eradication on hyperglycemia, insulin resistance, cytokine production, and insulin receptor substrate-1 and 2 expression in patients with HCV infection

Virological responses after hepatitis C virus (HCV) treatment may alleviate liver disease and extra-hepatic manifestations. Our study aims to explore the impact of HCV eradication on the glycemic status, insulin resistance, cytokine production, and insulin receptor substrate (IRS)-1 and 2 gene expression levels in HCV-hyperglycemic patients. A total of 90 participants were allocated as follows: Group 1 included 30 healthy subjects as controls, and Group 2 included 60 HCV-hyperglycemic patients treated with a direct-acting antiviral (DAA) regimen and further subdivided into HCV-pre-diabetic and HCV-diabetic groups. Laboratory assays screened patients before and after treatments. Our data showed an excellent rate of virological responses in HCV groups after HCV treatment. Moreover, HCV eradication significantly ameliorated blood glucose levels and insulin resistance biomarkers in HCV-hyperglycemic patients compared with baseline values. Also, interleukin (IL)-6, IL-17, IL-23, and IL-27 levels were significantly ameliorated after viral clearance in HCV-hyperglycemic patients compared with baseline values. Similarly, IRS-1 and 2 mRNA expression levels were upregulated in these patients post-HCV treatment compared with baseline values. HCV clearance ameliorated hyperglycemia, cytokine production, and enhanced insulin sensitivity. Future researches will be needed to explore the effects of cytokines and IRS on HCV infection and treatment on a large cohort.

Impaired immune response mediated by prostaglandin E2 promotes severe COVID-19 disease

The SARS-CoV-2 coronavirus has led to a pandemic with millions of people affected. The present study finds that risk-factors for severe COVID-19 disease courses, i.e. male sex, older age and sedentary life style are associated with higher prostaglandin E2 (PGE2) serum levels in blood samples from unaffected subjects. In COVID-19 patients, PGE2 blood levels are markedly elevated and correlate positively with disease severity. SARS-CoV-2 induces PGE2 generation and secretion in infected lung epithelial cells by upregulating cyclo-oxygenase (COX)-2 and reducing the PG-degrading enzyme 15-hydroxyprostaglandin-dehydrogenase. Also living human precision cut lung slices (PCLS) infected with SARS-CoV-2 display upregulated COX-2. Regular exercise in aged individuals lowers PGE2 serum levels, which leads to increased Paired-Box-Protein-Pax-5 (PAX5) expression, a master regulator of B-cell survival, proliferation and differentiation also towards long lived memory B-cells, in human pre-B-cell lines. Moreover, PGE2 levels in serum of COVID-19 patients lowers the expression of PAX5 in human pre-B-cell lines. The PGE2 inhibitor Taxifolin reduces SARS-CoV-2-induced PGE2 production. In conclusion, SARS-CoV-2, male sex, old age, and sedentary life style increase PGE2 levels, which may reduce the early anti-viral defense as well as the development of immunity promoting severe disease courses and multiple infections. Regular exercise and Taxifolin treatment may reduce these risks and prevent severe disease courses.

Role of IL-6-IL-27 Complex in Host Antiviral Immune Response

The IL family of cytokines participates in immune response and regulation. We previously found that soluble IL-6 receptor plays an important role in the host antiviral response. In this study, we detected the IL-6-IL-27 complex in serum and throat swab samples from patients infected with influenza A virus. A plasmid expressing the IL-6-IL-27 complex was constructed to explore its biological function. The results indicated that the IL-6-IL-27 complex has a stronger antiviral effect than the individual subunits of IL-6, IL-27A, and EBV-induced gene 3. Furthermore, the activity of the IL-6-IL-27 complex is mainly mediated by the IL-27A subunit and the IL-27 receptor α. The IL-6-IL-27 complex can positively regulate virus-triggered expression of IFN and IFN-stimulated genes by interacting with adaptor protein mitochondrial antiviral signaling protein, potentiating the ubiquitination of TNF receptor-associated factors 3 and 6 and NF-κB nuclear translocation. The secreted IL-6-IL-27 complex can induce the phosphorylation of STAT1 and STAT3 and shows antiviral activity. Our results demonstrate a previously unrecognized mechanism by which IL-6, IL-27A, and EBV-induced gene 3 form a large complex both intracellularly and extracellularly, and this complex acts in the host antiviral response.

TLR7 Ligation Inhibits TLR8 Responsiveness in IL-27-Primed Human THP-1 Monocytes and Macrophages

Regulation of proinflammatory cytokine expression is critical in the face of single-stranded RNA (ssRNA) virus infections. Many viruses, including coronavirus and influenza virus, wreak havoc on the control of cytokine expression, leading to the formation of detrimental cytokine storms. Understanding the regulation and interplay between inflammatory cytokines is critical to the identification of targets involved in controlling the induction of cytokine expression. In this study, we focused on how the antiviral cytokine interleukin-27 (IL-27) regulates signal transduction downstream of Toll-like receptor 7 (TLR7) and TLR8 ligation, which recognize endosomal single-stranded RNA. Given that IL-27 alters bacterial-sensing TLR expression on myeloid cells and can inhibit replication of single-stranded RNA viruses, we investigated whether IL-27 affects expression and function of TLR7 and TLR8. Analysis of IL-27-treated THP-1 monocytic cells and THP-1-derived macrophages revealed changes in mRNA and protein expression of TLR7 and TLR8. Although treatment with IL-27 enhanced TLR7 expression, only TLR8-mediated cytokine secretion was amplified. Furthermore, we demonstrated that imiquimod, a TLR7 agonist, inhibited cytokine and chemokine production induced by a TLR8 agonist, TL8-506. Delineating the immunomodulatory role of IL-27 on TLR7 and TLR8 responses provides insight into how myeloid cell TLR-mediated responses are regulated during virus infection.

Effects of arsenic and heavy metals on metabolic pathways in cells of human origin: Similarities and differences

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There are distinctive overlaps in different heavy metal affected metabolic pathways.

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Affected pathways vary according to the tissue origin and maturity of the cell.

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Arsenic appears to have relatively more pleiotropic effects on metabolic pathways.

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Some of the arsenic affected pathways are associated with diabetes.

Various anthropogenic and natural events over the years have gradually increased human exposure to various heavy metals. Several of these heavy metals including cadmium, mercury, nickel, chromium, and the metalloid arsenic among others, have created major public health concerns for their high level of toxicities. Identification of the general as well as the differentially affected cellular metabolic pathways will help understanding the molecular mechanism of different heavy metal-induced toxicities. In this study, we analyzed 25 paired (control vs. treated) transcriptomic datasets derived following treatment of various human cells with different heavy metals and metalloid (arsenic, cadmium, chromium, iron, mercury, nickel and vanadium) to identify the affected metabolic pathways. The effects of these metals on metabolic pathways depend not only on the metals per se, but also on the nature of the treated cells. Tissue of origin, therefore, must be considered while assessing the effects of any particular heavy metal or metalloid. Among the metals and metalloid, arsenic appears to have relatively more pleiotropic influences on cellular metabolic pathways including those known to have association with diabetes. Although only two stem cell derived datasets are included in the current study, effects of heavy metals on these cells appear to be different from other mature cells of similar tissue origin. This study provides useful information about different heavy metal affected pathways, which may be useful in further exploration using wet-lab based techniques.

Sox4 represses host innate immunity to facilitate pathogen infection by hijacking the TLR signaling networks

Toll-like receptors (TLRs) are essential for the protection of the host from pathogen infections by initiating the integration of contextual cues to regulate inflammation and immunity. However, without tightly controlled immune responses, the host will be subjected to detrimental outcomes. Therefore, it is important to balance the positive and negative regulations of TLRs to eliminate pathogen infection, yet avert harmful immunological consequences. This study revealed a distinct mechanism underlying the regulation of the TLR network. The expression of sex-determining region Y-box 4 (Sox4) is induced by virus infection in viral infected patients and cultured cells, which subsequently represses the TLR signaling network to facilitate viral replication at multiple levels by a distinct mechanism. Briefly, Sox4 inhibits the production of myeloid differentiation primary response gene 88 (MyD88) and most of the TLRs by binding to their promoters to attenuate gene transcription. In addition, Sox4 blocks the activities of the TLR/MyD88/IRAK4/TAK1 and TLR/TRIF/TRAF3/TBK1 pathways by repressing their key components. Moreover, Sox4 represses the activation of the nuclear factor kappa-B (NF-κB) through interacting with IKKα/α, and attenuates NF-kB and IFN regulatory factors 3/7 (IRF3/7) abundances by promoting protein degradation. All these contributed to the down-regulation of interferons (IFNs) and IFN-stimulated gene (ISG) expression, leading to facilitate the viral replications. Therefore, we reveal a distinct mechanism by which viral pathogens evade host innate immunity and discover a key regulator in host defense.

Role of p38 mitogen-activated protein kinase signalling in virus replication and potential for developing broad spectrum antiviral drugs

Mitogen-activated protein kinases (MAPKs) play a key role in complex cellular processes such as proliferation, development, differentiation, transformation and apoptosis. Mammals express at least four distinctly regulated groups of MAPKs which include extracellular signal-related kinases (ERK)-1/2, p38 proteins, Jun amino-terminal kinases (JNK1/2/3) and ERK5. p38 MAPK is activated by a wide range of cellular stresses and modulates activity of several downstream kinases and transcription factors which are involved in regulating cytoskeleton remodeling, cell cycle modulation, inflammation, antiviral response and apoptosis. In viral infections, activation of cell signalling pathways is part of the cellular defense mechanism with the basic aim of inducing an antiviral state. However, viruses can exploit enhanced cell signalling activities to support various stages of their replication cycles. Kinase activity can be inhibited by small molecule chemical inhibitors, so one strategy to develop antiviral drugs is to target these cellular signalling pathways. In this review, we provide an overview on the current understanding of various cellular and viral events regulated by the p38 signalling pathway, with a special emphasis on targeting these events for antiviral drug development which might identify candidates with broad spectrum activity.

Profiles of Long Non-Coding RNAs and mRNA Expression in Human Macrophages Regulated by Interleukin-27

Macrophages play an essential role in the immune system. Recent studies have shown that long non-coding RNAs (lncRNAs) can regulate genes encoding products involved in the immune response. Interleukin (IL)-27 is a member of the IL-6/IL-12 family of cytokines with broad anti-viral effects that inhibits human immunodeficiency virus (HIV) type-1 and herpes simplex virus (HSV). However, little is known about the role of lncRNAs in macrophages affected by IL-27. Therefore, we investigated the expression profiles of mRNA and lncRNA in human monocyte-derived macrophages (MDMs) regulated by IL-27. Monocytes were differentiated in the presence of macrophage-colony stimulatory factor (M-CSF)- or human AB serum with or without IL-27, and these cells were the subject for the profile analysis using RNA-Seq. We identified 146 lncRNAs (including 88 novel ones) and 434 coding genes were differentially regulated by IL-27 in both M-CSF- and AB serum-induced macrophages. Using weighted gene co-expression network analysis, we obtained four modules. The immune system, cell cycle, and regulation of complement cascade pathways were enriched in different modules. The network of mRNAs and lncRNAs in the pathways suggest that lncRNAs might regulate immune activity in macrophages. This study provides potential insight into the roles of lncRNA in macrophages regulated by IL-27.

Polygalasaponin F treats mice with pneumonia induced by influenza virus

BACKGROUND

Influenza is an acute viral respiratory illness that causes high morbidity and mortality globally. Therapeutic actions are limited to vaccines and a few anti-viral drugs. Polygala (P.) japonica herba is rich in Polygalasaponin F (PSF, C₅₃H₈₆O₂₃), used for acute bronchitis, pharyngitis, pneumonia, amygdalitis, and respiratory tract infections treatment in China. Hypercytokinemia is often correlated with severe pneumonia caused by several influenza viruses. PSF was reported to have anti-inflammatory effects and its mechanism is associated with the nuclear factor (NF)-κB signaling pathway. The action of PSF to alleviate pulmonary inflammation caused by influenza A virus (IAV) infection requires careful assessment. In the present study, we evaluated the effect and mechanism of PSF on mice with pneumonia caused by influenza H1N1 (A/FM/1/47).

METHODS

Mice were infected intranasally with fifteen 50% mouse lethal challenge doses (MLD₅₀) of influenza virus. BALB/c mice were treated with PSF or oseltamivir (oral administration) for 2 h post-infection and received concomitant treatment for 5 days after infection. On day 6 post-infection, 10 mice per group were killed to collect related samples, measure body weight and lung wet weight, and detect the viral load, cytokine, prostaglandins, pathological changes, and cell pathway protein expression in the lungs. In addition, the survival experiments were carried out to investigate the survival of mice. The expression profile of cell pathway proteins was detected and analyzed using a broad pathway antibody array and confirmed the findings from the array by western blotting.

RESULTS

Polygalasaponin F and oseltamivir can protect against influenza viral infection in mice. PSF and oseltamivir significantly relieved the signs and symptoms, reduced body weight loss, and improved the survival rate of H1N1-infected mice. Moreover, PSF efficiently decreased the level of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-4, interferon (IFN)-γ, thromboxane A₂ (TXA₂), and prostaglandin E₂ (PGE₂) in lung tissues of mice infected with influenza virus (p < 0.05-0.01). Oseltamivir had a similar effect to lung cytokine of PSF, but did not decrease the levels of TXA₂ and PGE₂. There was a twofold or greater increase in four cell pathway protein, namely NF-κB p65 (2.68-fold), I-kappa-B-alpha (IκBα) (2.56-fold), and MAPK/ERK kinase 1 (MEK1) (7.15-fold) assessed in the array induced by influenza virus. Western blotting showed that the expression of these proteins was significantly decreased in lung after influenza virus challenge in PSF and oseltamivir-treated mice (p < 0.05-0.01).

CONCLUSION

Polygalasaponin F appears to be able to augment protection against IAV infection in mice via attenuation of pulmonary inflammatory responses. Its effect on IAV-induced pulmonary inflammation was associated with suppression of Raf/MEK/ERK and NF-κB expressions.

Immunoregulatory Functions of the IL-12 Family of Cytokines in Antiviral Systems

Members of the interleukin 12 (IL-12) family have been known to be inflammatory factors since their discovery. The IL-12 family consists of IL-12, IL-23, IL-27, IL-35, and a new member, IL-39, which has recently been identified and has not yet been studied extensively. Current literature has described the mechanisms of immunity of these cytokines and potential uses for therapy and medical cures. IL-12 was found first and is effective in combatting a wide range of naturally occurring viral infections through the upregulation of various cytokines to clear the infected cells. IL-23 has an essential function in immune networks, can induce IL-17 production, and can antagonize inhibition from IL-12 in the presence of T helper (Th) 17 cells, resulting in type II IFN (IFN-γ) regulation. IL-27 has a competitive relationship to IL-35 because they both include the same subunit, the Epstein–Barr virus-induced gene3 (EBi3). This review provides a simple introduction to the IL-12 family and focuses on their functions relevant to their actions to counteract viral infections.

Epigenetic Modification Is Regulated by the Interaction of Influenza A Virus Nonstructural Protein 1 with the De Novo DNA Methyltransferase DNMT3B and Subsequent Transport to the Cytoplasm for K48-Linked Polyubiquitination

The influenza virus nonstructural protein 1 (NS1) is a nonstructural protein that plays a major role in antagonizing host interferon responses during infection. However, a clear role for the NS1 protein in epigenetic modification has not been established. In this study, NS1 was found to regulate the expression of some key regulators of JAK-STAT signaling by inhibiting the DNA methylation of their promoters. Furthermore, DNA methyltransferase 3B (DNMT3B) is responsible for this process. Upon investigating the mechanisms underlying this event, NS1 was found to interact with DNMT3B but not DNMT3A, leading to the dissociation of DNMT3B from the promoters of the corresponding genes. In addition, the interaction between NS1 and DNMT3B changed the localization of DNMT3B from the nucleus to the cytosol, resulting in K48-linked ubiquitination and degradation of DNMT3B in the cytosol. We conclude that NS1 interacts with DNMT3B and changes its localization to mediate K48-linked polyubiquitination, subsequently contributing to the modulation of the expression of JAK-STAT signaling suppressors.IMPORTANCE The nonstructural protein 1 (NS1) of the influenza A virus (IAV) is a multifunctional protein that counters cellular antiviral activities and is a virulence factor. However, the involvement of NS1 in DNA methylation during IAV infection has not been established. Here, we reveal that the NS1 protein binds the cellular DNMT3B DNA methyltransferase, thereby inhibiting the methylation of the promoters of genes encoding suppressors of JAK-STAT signaling. As a result, these suppressor genes are induced, and JAK-STAT signaling is inhibited. Furthermore, we demonstrate that the NS1 protein transports DNMT3B to the cytoplasm for ubiquitination and degradation. Thus, we identify the NS1 protein as a potential trigger of the epigenetic deregulation of JAK-STAT signaling suppressors and illustrate a novel mechanism underlying the regulation of host immunity during IAV infection.

Early transcriptome profile of goat peripheral blood mononuclear cells (PBMCs) infected with peste des petits ruminant's vaccine virus (Sungri/96) revealed induction of antiviral response in an interferon independent manner

Sungri/96 vaccine strain is considered the most potent vaccine providing long-term immunity against peste des petits ruminants (PPR) in India. Previous studies in our laboratory highlighted induction of robust antiviral response in an interferon independent manner at 48 h and 120 h post infection (p.i.). However, immune response at the earliest time point 6 h p.i. (time taken to complete one PPRV life cycle), in PBMCs infected with Sungri/96 vaccine virus has not been investigated. This study was taken up to understand the global gene expression profiling of goat PBMCs after Sungri/96 PPRV vaccine strain infection at 6 h post infection (p.i.). A total of 1926 differentially expressed genes (DEGs) were identified with 616 - upregulated and 1310 - downregulated. TLR7/TLR3, IRF7/IRF1, ISG20, IFIT1/IFIT2, IFITM3, IL27 and TREX1 were identified as key immune sensors and antiviral candidate genes. Interestingly, type I interferons (IFNα/β) were not differentially expressed at this time point as well. TREX1, an exonuclease which inhibits type I interferons at the early stage of virus infection was found to be highly upregulated. IL27, an important antiviral host immune factor was significantly upregulated. ISG20, an antiviral interferon induced gene with exonuclease activity specific to ssRNA viruses was highly expressed. Functional profiling of DEGs showed significant enrichment of immune system processes with 233 genes indicating initiation of immune defense response in host cells. Protein interaction network showed important innate immune molecules in the immune network with high connectivity. The study highlights important immune and antiviral genes at the earliest time point.

Influenza A virus inhibits influenza virus replication by inducing IL-37

BACKGROUNDS

The influenza virus is one of the major pathogens that seriously affect human health. It can cause a strong immune response and trigger a series of complications. Interleukin 37 (IL-37) is a newly discovered cytokine that plays an important regulatory role in infection and immunity. To date, there have been few studies on the correlation between influenza virus infection and IL-37.

METHODS

Serum levels of IL-37 in 115 patients with influenza A virus (IAV) infection and 102 healthy subjects were measured by an enzyme-linked immunosorbent assay (ELISA). Real-time quantitative PCR (RT-qPCR) was used to detect differences in IL-37 expression in peripheral blood mononuclear cells (PBMCs) between IAV patients and healthy subjects. IL-37 expression was measured in A549 cells and PBMCs infected with IAV H3N2 using ELISA and RT-qPCR. After the H3N2-infected A549 cells were treated with human IL-37, the concentration of viral RNA was determined using RT-qPCR, and the titer of influenza virus was determined by a hemagglutination test.

RESULTS

The IL-37 levels in the sera and PBMCs of patients infected with IAV were higher than those of healthy subjects. The expression of IL-37 mRNA and protein in IAV-infected A549 cells and PBMCs was upregulated, and IL-37 protein was able to inhibit the replication of IAV RNA.

CONCLUSION

IAV-induced IL-37 expression inhibits IAV replication.

REPA: Applying Pathway Analysis to Genome-Wide Transcription Factor Binding Data

Pathway analysis has been extensively applied to aid in the interpretation of the results of genome-wide transcription profiling studies, and has been shown to successfully find associations between the biological phenomena under study and biological pathways. There are two widely used approaches of pathway analysis: over-representation analysis, and gene set analysis. Recently genome-wide transcription factor binding data has become widely available allowing for the application of pathway analysis to this type of data. In this work, we developed regulatory enrichment pathway analysis (REPA) to apply gene set analysis to genome-wide transcription factor binding data to infer associations between transcription factors and biological pathways. We used the transcription factor binding data generated by the ENCODE project, and gene sets from the Molecular Signatures and KEGG databases. Our results showed that 54 percent of the predictions examined have literature support and that REPA's recall is roughly 54 percent. This level of precision is promising as several of REPA's predictions are expected to be novel and can be used to guide new research avenues. In addition, the results of our case studies showed that REPA enhances the interpretation of genome-wide transcription profiling studies by suggesting putative regulators behind the observed transcriptional responses.

IL-27 Expression and Responsiveness in Human Uterine Epithelial Cells and Fibroblasts In Vitro and the Role of Estradiol

Interleukin (IL)-27 is a pleiotropic cytokine that regulates multiple aspects of innate and adaptive immunity, but whose role in immune protection of the female reproductive tract is unknown. Although not constitutively expressed by human uterine epithelial cells and fibroblasts in culture, IL-27 secretion was upregulated after treatment with the viral ligand poly (I:C) in a type I interferon (IFN)-dependent manner, with higher levels measured in fibroblasts than epithelial cells. Estradiol increased poly (I:C)-induced IL-27 production by fibroblasts, but not epithelial cells. While both cell types expressed the IL-27 receptor, only fibroblasts responded to recombinant IL-27 with increased expression of the antiviral genes, APOBEC3G (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G) and MxA, and the tryptophan-catabolizing enzyme, indoleamine 2,3-dioxygenase (IDO). Estradiol inhibited IL-27-mediated induction of IDO in fibroblasts through estrogen receptor alpha, but had no effect on APOBEC3G. IL-27 pretreatment also potentiated poly (I:C) upregulation of the antiviral genes, OAS2 and APOBEC3G, in fibroblasts. Thus, IL-27 is part of the antiviral response by uterine cells against potential pathogens. The effect of estradiol on IL-27 production and sensitivity by fibroblasts demonstrates a selective hormone action on individual cell types in the uterus and suggests that IL-27 may have differential effects during the menstrual cycle.

Association of the Interleukin-27 Gene Expression and Hepatitis B Virus Infection in Liver Transplanted Patients

OBJECTIVES

Hepatitis B viral infection is among the most common causes of cirrhosis and hepatocellular carcinoma and a frequent viral indication for liver transplant. Cytokine-mediated immunity plays a critical role in introducing and promoting hepatitis B virus outcomes and in graft microenvironment. Interleukin 27 is a heterodimeric cytokine and a member of interleukin-6/interleukin-12 family. Interleukin-27 shows a broad range of pro- and antiinflammatory properties and plays a determining role during immune responses in combating hepatitis B virus. Therefore, in this study, the possible association between expressions of interleukin-27 gene with hepatitis B virus infection was evaluated in liver transplant patients.

MATERIALS AND METHODS

In a cross-sectional study from liver transplant patients with the risk of hepatitis B virus infection who admitted to Namazi Hospital affiliated to Shiraz University of Medical Sciences, 50 patients were selected and subgrouped to 25 hepatitis B virus-infected and 25 noninfected ones between years 2011 and 2013. The 25 healthy controls also were enrolled in this study. The presence of hepatitis B virus infection was assessed using polymerase chain reaction and enzyme-linked immunosorbent assay protocols in liver transplant patients. In addition, the interleukin-27 gene expression level was analyzed using an in-house-SYBER Green real time polymerase chain reaction method. The rate of interleukin-27 gene expression level was statistically analyzed in studied patient groups and controls using the Livak (2-▵▵CT) method.

RESULTS

The expression level of interleukin-27 gene was increased 10.27- and 2.36-fold in hepatitis B virus-infected and uninfected liver transplanted patients compared with healthy controls.

CONCLUSION

Hepatitis B virus infection can lead to overexpression of interleukin-27 gene in liver transplant patients compared with uninfected ones and controls. However, further studies are needed to characterize the effective antihepatitis B virus effects of interleukin-27 in liver transplant patients.

p38β Mitogen-Activated Protein Kinase Signaling Mediates Exenatide-Stimulated Microglial β-Endorphin Expression

Recent discoveries established that activation of glucagon-like peptide-1 receptors (GLP-1Rs) mediates neuroprotection and antinociception through microglial β-endorphin expression. This study aimed to explore the underlying signaling mechanisms of microglial β-endorphin. GLP-1Rs and β-endorphin were coexpressed in primary cultures of microglia. Treatment with the GLP-1R agonist exenatide concentration-dependently stimulated microglial expression of the β-endorphin precursor gene proopiomelanocortin (POMC) and peptides, with EC50 values of 4.1 and 7.5 nM, respectively. Exenatide also significantly increased intracellular cAMP levels and expression of p-protein kinase A (PKA), p-p38, and p-cAMP response element binding protein (CREB) in cultured primary microglia. Furthermore, exenatide-induced microglial expression of POMC was completely blocked by reagents that specifically inhibit adenylyl cyclase and activation of PKA, p38, and CREB. In addition, knockdown of p38β (but not p38α) using short interfering RNA (siRNA) eliminated exenatide-induced microglial p38 phosphorylation and POMC expression. In contrast, lipopolysaccharide increased microglial activation of p38, and knockdown of p38α (but not p38β) partially suppressed expression of proinflammatory factors (including tumor necrosis factor-α, interleukin-1β, and interleukin-6). Exenatide-induced phosphorylation of p38 and CREB was also totally blocked by the PKA inhibitor and siRNA/p38β, but not by siRNA/p38α Seven-day intrathecal injections of siRNA/p38β (but not siRNA/p38α) completely blocked exenatide-induced spinal p38 activation, β-endorphin expression, and mechanical antiallodynia in rats with established neuropathy, although siRNA/p38β and siRNA/p38α were not antiallodynic. To our knowledge, our results are the first to show a causal relationship between the PKA-dependent p38β mitogen-activated protein kinase/CREB signal cascade and GLP-1R agonism-mediated microglial β-endorphin expression. The differential role of p38α and p38β activation in inflammation and nociception was also highlighted.

Genome-Wide Analyses of MicroRNA Profiling in Interleukin-27 Treated Monocyte-Derived Human Dendritic Cells Using Deep Sequencing: A Pilot Study

MicroRNAs (miRNAs) regulate gene expression and thereby influence cell fate and function. Recent studies suggest that an abundant class of miRNAs play important roles in immune cells, such as T cells, natural killer (NK) cells, B cells, and dendritic cells (DCs). Interleukin (IL)-27 is a member of the IL-12 family of cytokines with broad anti-viral effects. It is a potent inhibitor of HIV-1 infection in CD4+ T cells and macrophages, as well as monocyte-derived immature dendritic cells (iDCs). This pilot study compared miRNA profiles between iDCs and IL-27-treated iDCs (27DCs) using deep sequencing methods and identified 46 known miRNAs that were significantly differentially expressed in 27DCs: 36 were upregulated and 10 downregulated by IL-27. Many of the potential target genes of these miRNAs are involved in IL-27 associated pathways, such as JAK/STAT, MAPKs, and PI3K and several were also previously reported to be involved in the regulation of human DC function. This study found that these miRNAs also potentially target several viral genomes and therefore may have antiviral effects. Four of these differential miRNAs (miR-99a-5p, miR-222-3p, miR-138-5p, and miR-125b-5p) were validated using quantitative reverse transcription PCR (RT-qPCR). Twenty-two novel miRNAs were discovered from deep sequencing and confirmed using RT-qPCR. This study furthers the understanding of the role of IL-27 in immunity and lays a foundation for future characterization of the role of specific miRNAs in DCs.

Inducible GBP5 Mediates the Antiviral Response via Interferon-Related Pathways during Influenza A Virus Infection

Guanylate binding protein (GBP) 5 belongs to the GBP family, which is involved in important cellular processes, including signal transduction, translation, vesicle trafficking, and exocytosis. Structurally, GBPs display a high degree of homology and share highly conserved GTP-binding or hydrolysis domains. GBP5 was reported to be a critical cellular factor in inflammasome assembly. However, little is known about its role in the host antiviral innate immune response. In this study, we found that GBP5 expression was significantly elevated in influenza patients and influenza A virus-infected A549 human lung epithelial cells. The overexpression of GBP5 inhibited virus replication by enhancing the expression of virus-induced interferon (IFN) and IFN-related effectors. Knockdown of GBP5 had the opposite effect. Moreover, GBP5 enhanced endogenous IFN expression by interacting with the NF-κB-essential modulator complex and stimulating NF-κB signaling. Additionally, the expression of proinflammatory factors, such as IL-6, IL-8, tumor necrosis factor-α, cyclooxygenase-2, and inducible nitric oxide synthase, was also activated by GBP5. Taken together, our results reveal that GBP5 inhibited virus replication through the activation of IFN signaling and proinflammatory factors.

The inflammatory response triggered by Influenza virus: a two edged sword

Influenza A virus (IAV) is a relevant respiratory tract pathogen leading to a great number of deaths and hospitalizations worldwide. Secondary bacterial infections are a very common cause of IAV associated morbidity and mortality. The robust inflammatory response that follows infection is important for the control of virus proliferation but is also associated with lung damage, morbidity and death. The role of the different components of immune response underlying protection or disease during IAV infection is not completely elucidated. Overall, in the context of IAV infection, inflammation is a 'double edge sword' necessary to control infection but causing disease. Therefore, a growing number of studies suggest that immunomodulatory strategies may improve disease outcome without affecting the ability of the host to deal with infection. This review summarizes recent aspects of the inflammatory responses triggered by IAV that are preferentially involved in causing severe pulmonary disease and the anti-inflammatory strategies that have been suggested to treat influenza induced immunopathology.

Prostaglandin E2 As a Modulator of Viral Infections

Viral infections are a major cause of infectious diseases worldwide. Inflammation and the immune system are the major host defenses against these viral infection. Prostaglandin E2 (PGE2), an eicosanoid generated by cyclooxygenases, has been shown to modulate inflammation and the immune system by regulating the expression/concentration of cytokines. The effect of PGE2 on viral infection and replication is cell type- and virus-family-dependent. The host immune system can be modulated by PGE2, with regards to immunosuppression, inhibition of nitrogen oxide (NO) production, inhibition of interferon (IFN) and apoptotic pathways, and inhibition of viral receptor expression. Furthermore, PGE2 can play a role in viral infection directly by increasing the production and release of virions, inhibiting viral binding and replication, and/or stimulating viral gene expression. PGE2 may also have a regulatory role in the induction of autoimmunity and in signaling via Toll-like receptors. In this review the known effects of PGE2 on the pathogenesis of various infections caused by herpes simplex virus, rotavirus, influenza A virus and human immunodeficiency virus as well the therapeutic potential of PGE2 are discussed.

Interleukin-27 Early Impacts Leishmania infantum Infection in Mice and Correlates with Active Visceral Disease in Humans

The complexity of Leishmania–host interactions, one of the main leishmaniasis issues, is yet to be fully understood. We detected elevated IL-27 plasma levels in European patients with active visceral disease caused by Leishmania infantum, which returned to basal levels after successful treatment, suggesting this cytokine as a probable infection mediator. We further addressed this hypothesis recurring to two classical susceptible visceral leishmaniasis mouse models. BALB/c, but not C57BL/6 mice, showed increased IL-27 systemic levels after infection, which was associated with an upregulation of IL-27p28 expression by dendritic cells and higher parasite burdens. Neutralization of IL-27 in acutely infected BALB/c led to decreased parasite burdens and a transient increase in IFN-γ⁺ splenic T cells, while administration of IL-27 to C57BL/6 promoted a local anti-inflammatory cytokine response at the site of infection and increased parasite loads. Overall, we show that, as in humans, BALB/c IL-27 systemic levels are infection dependently upregulated and may favor parasite installation by controlling inflammation.

The Influenza A Virus Non-structural Protein NS1 Upregulates The Expression of Collagen Triple Helix Repeat Containing 1 Protein

Influenza A virus (IAV) infection induces a strong immune response and regulates the expression of many host proteins. The collagen triple helix repeat containing 1 (CTHRC1) protein is a secreted protein that exhibits increased expression during the viral infection process. However, the regulatory function of IAV on CTHRC1 expression is obscure. In this study, we investigated the effect of IAV on CTHRC1 expression and its regulatory mechanism. A total of 106 serum specimens from healthy people and 80 serum specimens from patients infected with IAV were collected. The CTHRC1 levels in the sera from the IVA patients and healthy individuals were measured using an enzyme-linked immunosorbent assay (ELISA), and the differences were statistically analysed. A549 cells were infected with the IAV or delNS1 virus. Additionally, A549 cells were cotransfected with a eukaryotic non-structural NS1 protein gene expression plasmid and the CTHRC1 gene promoter reporter plasmid (pCTHRC1-Luc), and, the luciferase activities were assessed. The CTHRC1 mRNA and protein expression were detected using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively. The serum CTHRC1 level was significantly higher in the IAV patients than in the healthy individuals. IAV upregulated the CTHRC1 mRNA and protein expression. The non-structural NS1 protein specifically activated CTHRC1 gene promoter activity and upregulated CTHRC1 mRNA and protein expression. The activation function had a dose-dependent effect, indicating that influenza virus upregulated CTHRC1 expression through its NS1 protein.

Methylcrotonoyl-CoA carboxylase 1 potentiates RLR-induced NF-κB signaling by targeting MAVS complex

RNA virus infections are detected by the RIG-I family of receptors, which signal through the adaptor molecule mitochondrial antiviral signaling (MAVS). MAVS then recruits the adaptor’s tumor necrosis factor receptor-associated factor (TRAF) 3 and TRAF6, which in turn activate IRF3 and NF-κB, respectively, to induce interferons (IFNs) and inflammatory responses. Here we show that the biotin-containing enzyme methylcrotonoyl-CoA carboxylase 1 (MCCC1) enhances virus-induced, MAVS-mediated IFN and inflammatory cytokine expression through the NF-κB signaling pathway. MCCC1 knockdown strongly inhibits induction of IFNs and inflammatory cytokines. Furthermore, MCCC1 shows extensive antiviral activity toward RNA viruses, including influenza A virus, human enterovirus 71, and vesicular stomatitis virus. Here, we have elucidated the mechanism underlying MCCC1-mediated inhibition of viral replication. MCCC1 interacts with MAVS and components of the MAVS signalosome and contributes to enhanced production of type I IFNs and pro-inflammatory cytokines by promoting phosphorylation of the IκB kinase (IKK) complex and NF-κB inhibitor-α (IκBα), as well as NF-κB nuclear translocation. This process leads to activation of IFNs and cytokine expression and subsequent activation of IFN-stimulated genes, including double-stranded RNA-dependent protein kinase PKR and myxovirus resistance protein 1. These findings demonstrate that MCCC1 plays an essential role in virus-triggered, MAVS-mediated activation of NF-κB signaling.

Gene Expression and Antiviral Activity of Interleukin-35 in Response to Influenza A Virus Infection

Interleukin-35 (IL-35) is a newly described member of the IL-12 family. It has been reported to inhibit inflammation and autoimmune inflammatory disease and can increase apoptotic sensitivity. Little is known about the role of IL-35 during viral infection. Herein, high levels of IL-35 were found in peripheral blood mononuclear cells and throat swabs from patients with seasonal influenza A virus (IAV) relative to healthy individuals. IAV infection of human lung epithelial and primary cells increased levels of IL-35 mRNA and protein. Further studies demonstrated that IAV-induced IL-35 transcription is regulated by NF-κB. IL-35 expression was significantly suppressed by selective inhibitors of cyclooxygenase-2 (COX-2) and inducible nitric-oxide synthase, indicating their involvement in IL-35 expression. Interestingly, IL-35 production may have suppressed IAV RNA replication and viral protein synthesis via induction of type I and III interferons (IFN), leading to activation of downstream IFN effectors, including double-stranded RNA-dependent protein kinase, 2',5'-oligoadenylate synthetase, and myxovirus resistance protein. IL-35 exhibited extensive antiviral activity against the hepatitis B virus, enterovirus 71, and vesicular stomatitis virus. Our results demonstrate that IL-35 is a novel IAV-inducible cytokine, and its production elicits antiviral activity.

Comparative Transcriptome Analysis of Bombyx mori (Lepidoptera) Larval Midgut Response to BmNPV in Susceptible and Near-Isogenic Resistant Strains

Bombyx mori nucleopolyhedrovirus (BmNPV) is one of the primary pathogens causing severe economic losses in sericulture. However, the molecular mechanism of silkworm resistance to BmNPV remains largely unknown. Here, the recurrent parent P50 (susceptible strain) and the near-isogenic line BC9 (resistance strain) were used in a comparative transcriptome study examining the response to infection with BmNPV. A total of 14,300 unigenes were obtained from two different resistant strains; of these, 869 differentially expressed genes (DEGs) were identified after comparing the four transcriptomes. Many DEGs associated with protein metabolism, cytoskeleton, and apoptosis may be involved in the host response to BmNPV infection. Moreover, some immunity related genes were also altered following BmNPV infection. Specifically, after removing genetic background and individual immune stress response genes, 22 genes were found to be potentially involved in repressing BmNPV infection. These genes were related to transport, virus replication, intracellular innate immune, and apoptosis. Our study provided an overview of the molecular mechanism of silkworm resistance to BmNPV infection and laid a foundation for controlling BmNPV in the future.

Diminished COX-2/PGE2-Mediated Antiviral Response Due to Impaired NOX/MAPK Signaling in G6PD-Knockdown Lung Epithelial Cells

Glucose-6-phosphate dehydrogenase (G6PD) provides the reducing agent NADPH to meet the cellular needs for reductive biosynthesis and the maintenance of redox homeostasis. G6PD-deficient cells experience a high level of oxidative stress and an increased susceptibility to viral infections. Cyclooxygenase-2 (COX-2) is a key mediator in the regulation of viral replication and inflammatory response. In the current study, the role of G6PD on the inflammatory response was determined in both scramble control and G6PD-knockdown (G6PD-kd) A549 cells upon tumor necrosis factor-α (TNF-α) stimulation. A decreased expression pattern of induced COX-2 and reduced production of downstream PGE₂ occurred upon TNF-α stimulation in G6PD-kd A549 cells compared with scramble control A549 cells. TNF-α-induced antiviral activity revealed that decreased COX-2 expression enhanced the susceptibility to coronavirus 229E infection in G6PD-kd A549 cells and was a result of the decreased phosphorylation levels of MAPK (p38 and ERK1/2) and NF-κB. The impaired inflammatory response in G6PD-kd A549 cells was found to be mediated through NADPH oxidase (NOX) signaling as elucidated by cell pretreatment with a NOX2-siRNA or NOX inhibitor, diphenyleneiodonium chloride (DPI). In addition, NOX activity with TNF-α treatment in G6PD-kd A549 cells was not up-regulated and was coupled with a decrease in NOX subunit expression at the transcriptional level, implying that TNF-α-mediated NOX signaling requires the participation of G6PD. Together, these data suggest that G6PD deficiency affects the cellular inflammatory response and the decreased TNF-α-mediated antiviral response in G6PD-kd A549 cells is a result of dysregulated NOX/MAPK/NF-κB/COX-2 signaling.

Association of Interleukin-27 rs 153109 Single Nucleotide Polymorphism with Spontaneous Resolution of Hepatitis C Virus - Genotype 4a Infection in Egyptian Patients

BACKGROUND

HCV is a major global health problem. IL-27 is a member of the IL-6/IL-12 cytokine family with a broad range of anti-inflammatory properties. Recent studies highlighted the effect of a SNP in the IL-27 promoter region on modulating the progression of infectious diseases and individual responses to therapy.

AIM OF THE WORK

The present study investigated the potential role of (-964 A/G) SNP in the promoter region of IL-27p28 gene (alleles rs153109) on the outcome of HCV infection among genotype 4a infected patients.

MATERIALS AND METHODS

HCV genotyping confirmed that all of the HCV-infected patients had genotype 4a infection. Genomic DNA was extracted from 111 patients with chronic HCV infection, 42 spontaneous resolvers (SR) and 16 healthy controls. IL- 27p28.rs153109 genotyping was assessed using PCR-RFLP then confirmed by DNA sequencing.

RESULTS

The frequency of IL-27-p28.rs153109AA, AG, and GG genotypes among chronically infected subjects were 74.8 %, 25.2%, and 0% while among the SR, they were 57.1%, 35.7%, and 7.14%, respectively. Our data show the unique presence of G/G genotype in the SR group (3 patients; 7.14%). Moreover, the "G" allele frequencies among chronic and resolved subjects were 12.6% and 25.0%, respectively (p=0.0136). Importantly, subjects with the GG genotype were more likely to clear their HCV infection than those with the AA genotype (p=0.0118).

CONCLUSIONS

HCV genotype 4a subjects with the IL-27-p28.rs153109 A/G and G/G genotype were more likely to clear their HCV infection. Therefore, we propose IL- 27p28.rs153109SNPas a genetic biomarker for predicting HCV infection outcome.

Mir-302c mediates influenza A virus-induced IFNβ expression by targeting NF-κB inducing kinase

Little is known about the role of microRNA during influenza A virus (IAV) infection. We observed that NIK 3'UTR luciferase activity was elevated during IAV infection. Further studies demonstrated that miR-302c reduced NIK expression, resulting in the reduction of IFNβ mRNA expression. We found that miR-302c prevented the translocation of NF-κB from the cytosol to the nucleus. Furthermore, IAV infection downregulated miR-302c expression, leading to the activation of IFNβ expression and the inhibition of viral replication. Compared to miR-302c, miR-520e cannot promote viral replication and production, although the two microRNAs target the same site of the NIK 3'UTR. Collectively, our work defines a novel signaling pathway implicated in the control of IFNβ mRNA expression during IAV infection.

IL-27 enhances innate immunity of human pulmonary fibroblasts and epithelial cells through upregulation of TLR4 expression

Lung tissue cells play an active role in the pathogenesis of pulmonary inflammatory diseases by releasing a variety of cytokines and chemokines. However, how lung tissue cells respond to microbial stimuli during pulmonary infections remains unclear. In this study, we found that patients with community-acquired pneumonia displayed increased IL-27 levels in bronchoalveolar lavage fluid and serum. We subsequently examined the immunopathological mechanisms for the activation of primary human lung fibroblasts and bronchial epithelial cells by IL-27. We demonstrated that IL-27 priming enhanced LPS-induced production of IL-6 and IL-8 from lung fibroblasts and bronchial epithelia cells via upregulating Toll-like receptor-4 (TLR4) expression. IL-27 upregulated TLR4 expression in lung fibroblasts through activation of Janus-activated kinase (JAK) and Jun NH2-terminal kinase (JNK) signaling pathways, and inhibition of the JAK pathway could partially decrease IL-27-induced TLR4 expression, while inhibition of JNK pathway could completely suppress IL-27-induced TLR4 expression. Our data suggest that IL-27 modulates innate immunity of lung tissue cells through upregulating TLR4 expression during pulmonary infections.

Potent therapeutic target of inflammation, virus and tumor: focus on interleukin-27

Interleukin (IL)-27 is an important pleiotropic immunological regulator for having dual effects on the immune responses. Several distinct findings have been highlighted that in certain conditions, neutralizing IL-27 or its subunit IL-27p28 might be a useful strategy to limit inflammation. Recently more insights have revealed that IL-27 could also exert potent inhibitory functions in some other immune circumstances including virus infection and tumor immunity. In this review, we describe IL-27 receptor subunits and the mechanisms of individual IL-27, and summarize the advances of their preclinical application trials. In addition, the potential role of IL-27 as a clinical therapeutic target will also be discussed.

Antibody-dependent enhancement infection facilitates dengue virus-regulated signaling of IL-10 production in monocytes

Background

Interleukin (IL)-10 levels are increased in dengue virus (DENV)-infected patients with severe disorders. A hypothetical intrinsic pathway has been proposed for the IL-10 response during antibody-dependent enhancement (ADE) of DENV infection; however, the mechanisms of IL-10 regulation remain unclear.

Principle Finding

We found that DENV infection and/or attachment was sufficient to induce increased expression of IL-10 and its downstream regulator suppressor of cytokine signaling 3 in human monocytic THP-1 cells and human peripheral blood monocytes. IL-10 production was controlled by activation of cyclic adenosine monophosphate response element-binding (CREB), primarily through protein kinase A (PKA)- and phosphoinositide 3-kinase (PI3K)/PKB-regulated pathways, with PKA activation acting upstream of PI3K/PKB. DENV infection also caused glycogen synthase kinase (GSK)-3β inactivation in a PKA/PI3K/PKB-regulated manner, and inhibition of GSK-3β significantly increased DENV-induced IL-10 production following CREB activation. Pharmacological inhibition of spleen tyrosine kinase (Syk) activity significantly decreased DENV-induced IL-10 production, whereas silencing Syk-associated C-type lectin domain family 5 member A caused a partial inhibition. ADE of DENV infection greatly increased IL-10 expression by enhancing Syk-regulated PI3K/PKB/GSK-3β/CREB signaling. We also found that viral load, but not serotype, affected the IL-10 response. Finally, modulation of IL-10 expression could affect DENV replication.

Significance

These results demonstrate that, in monocytes, IL-10 production is regulated by ADE through both an extrinsic and an intrinsic pathway, all involving a Syk-regulated PI3K/PKB/GSK-3β/CREB pathway, and both of which impact viral replication.

IL-10 has multiple cellular functions, including anti-inflammatory and immunomodulatory effects. Clinical studies have demonstrated that the serum levels of IL-10 are significantly increased in DENV-infected patients with severe disorders. However, the molecular mechanism underlying DENV-induced IL-10 production is still unresolved. In this study, we demonstrate a molecular mechanism for DENV-induced IL-10 production, which may be exacerbated by ADE through Fcγ receptor-mediated extrinsic and intrinsic pathways, leading to IL-10/SOCS3-mediated advantages for viral replication. With or without Fcγ receptor- or CLEC5A-mediated DENV infection, a common Syk/PKA-regulated PI3K/PKB activation results in a decrease in GSK-3β activity followed by an increase in CREB-mediated IL-10 expression not only in THP-1 monocytic cells but also in human monocytes. Taken together, we demonstrate a potential regulation and a pathological role for ADE-induced IL-10 overproduction during DENV replication. Therefore, inhibiting immunosuppression by targeting the IL-10 pathways identified in this study may help to prevent the progression of severe dengue diseases.

IL-27 enhances Leishmania amazonensis infection via ds-RNA dependent kinase (PKR) and IL-10 signaling

The protozoan parasite Leishmania infects and replicates in macrophages, causing a spectrum of diseases in the human host, varying from cutaneous to visceral clinical forms. It is known that cytokines modulate the immunological response against Leishmania and are relevant for infection resolution. Here, we report that Interleukin (IL)-27 increases Leishmania amazonensis replication in human and murine macrophages and that the blockage of the IL-10 receptor on the surface of infected cells abolished the IL-27-mediated enhancement of Leishmania growth. IL-27 induced the activation/phosphorylation of protein kinase R (PKR) in macrophages, and PKR blockage or PKR gene deletion abrogated the enhancement of the parasite growth driven by IL-27, as well as the L. amazonensis-induced macrophage production of IL-27. We also observed that L. amazonensis-induced expression of IL-27 depends on type I interferon signaling and the engagement of Toll-like receptor 2. Treatment of Leishmania-infected mice with IL-27 increased lesion size and parasite loads in the footpad and lymph nodes of infected animals, indicating that this cytokine exerts a local and a systemic effect on parasite growth and propagation. In conclusion, we show that IL-27 is a L. amazonensis-enhancing factor and that the PKR/IFN1 axis and IL-10 are critical mediators of this IL-27 induced effect.