The herpes simplex virus ICP0 RING finger domain inhibits IRF3- and IRF7-mediated activation of interferon-stimulated genes

Virus infection induces a rapid cellular response in cells characterized by the induction of interferon. While interferon itself does not induce an antiviral response, it activates a number of interferon-stimulated genes that collectively function to inhibit virus replication and spread. Previously, we and others reported that herpes simplex virus type 1 (HSV-1) induces an interferon -independent antiviral response in the absence of virus replication. Here, we report that the HSV-1 proteins ICP0 and vhs function in concert to disable the host antiviral response. In particular, we show that ICP0 blocks interferon regulatory factor IRF3- and IRF7-mediated activation of interferon-stimulated genes and that the RING finger domain of ICP0 is essential for this activity. Furthermore, we demonstrate that HSV-1 modifies the IRF3 pathway in a manner different from that of the small RNA viruses most commonly studied.     

The nitric oxide pathway provides innate antiviral protection in conjunction with the type I interferon pathway in fibroblasts

The innate host response to virus infection is largely dominated by the production of type I interferon and interferon stimulated genes. In particular, fibroblasts respond robustly to viral infection and to recognition of viral signatures such as dsRNA with the rapid production of type I interferon; subsequently, fibroblasts are a key cell type in antiviral protection. We recently found, however, that primary fibroblasts deficient for the production of interferon, interferon stimulated genes, and other cytokines and chemokines mount a robust antiviral response against both DNA and RNA viruses following stimulation with dsRNA. Nitric oxide is a chemical compound with pleiotropic functions; its production by phagocytes in response to interferon-γ is associated with antimicrobial activity. Here we show that in response to dsRNA, nitric oxide is rapidly produced in primary fibroblasts. In the presence of an intact interferon system, nitric oxide plays a minor but significant role in antiviral protection. However, in the absence of an interferon system, nitric oxide is critical for the protection against DNA viruses. In primary fibroblasts, NF-κB and interferon regulatory factor 1 participate in the induction of inducible nitric oxide synthase expression, which subsequently produces nitric oxide. As large DNA viruses encode multiple and diverse immune modulators to disable the interferon system, it appears that the nitric oxide pathway serves as a secondary strategy to protect the host against viral infection in key cell types, such as fibroblasts, that largely rely on the type I interferon system for antiviral protection.     

Antiviral and antiproliferative activity of human interferons and their induction of 2',5'-oligoadenylate synthetase

Native preparations of alpha, beta and gamma-interferons as well as recombinant beta-interferon and purified leukocyte alpha-interferon and purified leukocyte alpha-interferon exert antiviral and antiproliferative activity in CaOv cells. Native interferon preparations were shown to be more antiproliferative than purified interferons per unit of antiviral activity (with EMC as well as with less susceptible VSV used as test viruses). It was shown that level of 2'5' oligoadenylatesynthetase activity induction in general correlates with antiproliferative and pronounced antiviral activity of interferons, besides that, the earlier (by 11 hours) induction of the enzyme activity by beta-interferon correlates with more rapid expression of antiproliferative effects by this interferon in comparison with that of alpha-interferon, the latter inducing the peak of enzyme activity by 24 hours.     

Dissociation of protein kinase activity and the induction of the antiviral state in a cell line responsive to the antiviral effects of interferon

Interferons or oxidized glutathione were found to induce double-stranded RNA-dependent protein kinase activity in mouse L cells that phosphorylates the α subunit of eukaryotic peptide initiation factor 2. A mixture of leukocyte/fibroblast interferons as well as immune interferon induced the protein kinase and also suppressed virus replication in the L cells. Oxidized glutathione was equally effective in inducing protein kinase activity, but it did not induce an antiviral state in these cells. The data suggest that a simple cause and effect relationship does not exist between protein kinase induction and the establishment of the antiviral state in a cell that is responsive to the antiviral effects of interferon.     

Identification of a novel pathway essential for the immediate-early, interferon-independent antiviral response to enveloped virions

Viral infection elicits the activation of numerous cellular signal transduction pathways, leading to the induction of both innate and adaptive immunity. Previously we showed that entry of virion particles from a diverse array of enveloped virus families was capable of eliciting an interferon regulatory factor 3 (IRF-3)-mediated antiviral state in human fibroblasts in the absence of interferon production. Here we show that extracellular regulated kinase 1/2, p38 mitogen-activated protein kinase, and Jun N-terminal kinase/stress-activated protein kinase activities are not required for antiviral state induction. In contrast, treatment of cells with LY294002, an inhibitor of the phosphoinositide 3-kinase (PI3 kinase) family, prevents the induction of interferon-stimulated gene 56 (ISG56) and an antiviral response upon entry of virus particles. However, the prototypic class I p85/p110 PI3 kinase and its downstream effector Akt/PKB are dispensable for ISG and antiviral state induction. Furthermore, DNA-PK and PAK1, LY294002-sensitive members of the PI3 kinase family shown previously to be involved in IRF-3 activation, are also dispensable for ISG and antiviral state induction. The LY294002 inhibitor fails to prevent IRF-3 homodimerization or nuclear translocation upon virus particle entry. Together, these data suggest that virus entry triggers an innate antiviral response that requires the activity of a novel PI3 kinase family member.     

Effects of butyrate on induction and action of interferon

We have identified two different and independent effects of sodium butyrate on induction and action of interferon. In the monkey cell line, GL-V3, simultaneous treatment with interferon and butyrate strongly reduced the antiviral activity of the interferon preparation, Whereas addition of butyrate before interferon or after establishment of the antiviral state had no effect. Interferon production induced by Sendai virus was also reduced by simultaneous treatment with butyrate, but pretreatment resulted in marked enhancement of interferon yields. Whereas the inhibitory effects of simultaneous butyrate treatment were also observed in human (WISH) and bovine (MDBK) cells, pretreatment with butyrate in these cells had no effect on interferon yields.     

Characteristics of the factors that suppress and stimulate interferon production

A repressor of interferon production is contained in the hyaloplasm of the chick embryo fibroblast cells in the state of hyporeactivity. A factor stimulating interferon production (FSIP) was found in the hyaloplasm of the cells subjected to single or double induction with poly (pI) x poly (pC) followed by exposure to actinomycin D. Both preparations were of the protein nature and possessed high biological activity. They repressed or stimulatd interferon production at a dilution of 1:512-1:1024. The preparations had tissue and inductor specificity, did not affect the Venezuelan equine encephalomyelitis virus and interferon antiviral activity. Unlike the repressor, the FSIP proved to be thermolabile and pH-sensitive in acid media. The half lives of the repressor and stimulator were about 10 and 5 hours respectively.     

Failure to induce an antiviral state in preimplantation bovine embryos treated with interferon

Bovine blastocysts hatched from their zonae pellucidae were cultured for 24 h in the presence or absence of interferon and then challenged with either vesicular stomatitis virus or bluetongue virus to assess the induction of an antiviral state. In contrast to its application to fetal bovine cells, where significant antiviral effects were induced, interferon treatment of embryos failed to reduce virus yield and had no effect on virus-induced cytopathology. This lack of biologic activity of interferon in bovine embryos is similar to that previously observed with undifferentiated murine embryonal carcinoma cells and is probably a manifestation of a more general mechanism regulating gene expression in the early mammalian embryo.     

重组人干扰素α1b抗新型冠状病毒的基础和临床研究进展

干扰素是机体抗病毒的第一道天然防线,干扰素α1b是中国人干扰素家族中主要的抗病毒表达亚型。SARS-CoV-2通过多种途径抑制先天免疫关键分子干扰素的产生。已上市多年的重组人干扰素α1b显示出强大的体外抗SARS-CoV-2病毒活性。初步临床研究显示,包括重组人干扰素α1b在内的I型干扰素对COVID-19显示出积极的治疗和预防作用。全球多个国家正在开展干扰素治疗COVID-19的临床试验,我国自主知识产权的重组人干扰素α1b率先开展了验证性临床试验。     

Modulation of the interferon antiviral response by the TBK1/IKKi adaptor protein TANK

Induction of type I interferons can be triggered by viral components through Toll-like receptors or intracellular viral receptors such as retinoic acid-inducible gene I. Here, we demonstrate that the TRAF (tumor necrosis factor receptor-associated factor) family member-associated NF-kappaB activator (TANK) plays an important role in interferon induction through both retinoic acid-inducible gene I- and Toll-like receptor-dependent pathways. TANK forms complexes with both upstream signal mediators, such as Cardif/MAVS/IPS-1/VISA, TRIF (Toll-interleukin-1 receptor domain-containing adaptor inducing interferon-beta), and TRAF3 and downstream mediators TANK-binding kinase 1, inducible IkappaB kinase, and interferon regulatory factor 3. In addition, it synergizes with these signaling components in interferon induction. Specific knockdown of TANK results in reduced type I interferon production, increased viral titers, and enhanced cell sensitivity to viral infection. Thus, TANK may be a critical adaptor that regulates the assembly of the TANK-binding kinase 1-inducible IkappaB kinase complex with upstream signaling molecules in multiple antiviral pathways.     

Acridonacetic acid: pharmacological properties and clinical use

The summarized data on the biological activity of acridoneacetic acid, a low-molecular interferon inducer are presented: the amount and type of induced interferon, producer cells, interaction with viruses; the antiviral, antitumoral and anti-inflammatory activity of the preparation has been demonstrated. The specific features of interferon induction by virus (a biological inducer), in contrast to acridoneacetic acid (a chemical inducer) have been noted. The possible mechanisms of interferon induction by low-molecular interferonogen are considered. A number of interferonogens, salts of acridoneacetic acid, proposed as medicinal preparations are considered. The results of the clinical use of Cycloferon, a medicinal form of acridoneacetic acid, are presented.