RARγ activation sensitizes human myeloma cells to carfilzomib treatment through the OAS-RNase L innate immune pathway.

Proteasome inhibitors (PIs) such as bortezomib (Btz) and carfilzomib (Cfz) are highly efficacious for patients with multiple myeloma (MM). However, relapses are frequent, and acquired resistance to PI treatment emerges in most patients. Here, we performed a high-throughput screen of 1855 Food and Drug Administration (FDA)-approved drugs and identified all-trans retinoic acid (ATRA), which alone has no antimyeloma effect, as a potent drug that enhanced MM sensitivity to Cfz-induced cytotoxicity and resensitized Cfz-resistant MM cells to Cfz in vitro. ATRA activated retinoic acid receptor (RAR)γ and interferon-ß response pathway, leading to upregulated expression of IRF1. IRF1 in turn initiated the transcription of OAS1, which synthesized 2-5A upon binding to double-stranded RNA (dsRNA) induced by Cfz and resulted in cellular RNA degradation by RNase L and cell death. Similar to ATRA, BMS961, a selective RARγ agonist, could also (re)sensitize MM cells to Cfz in vitro, and both ATRA and BMS961 significantly enhanced the therapeutic effects of Cfz in established MM in vivo. In support of these findings, analyses of large datasets of patients' gene profiling showed a strong and positive correlation between RARγ and OAS1 expression and patient's response to PI treatment. Thus, this study highlights the potential for RARγ agonists to sensitize and overcome MM resistance to Cfz treatment in patients.

Regulation of innate immune responses in macrophages differentiated in the presence of vitamin D and infected with dengue virus 2.

A dysregulated or exacerbated inflammatory response is thought to be the key driver of the pathogenesis of severe disease caused by the mosquito-borne dengue virus (DENV). Compounds that restrict virus replication and modulate the inflammatory response could thus serve as promising therapeutics mitigating the disease pathogenesis. We and others have previously shown that macrophages, which are important cellular targets for DENV replication, differentiated in the presence of bioactive vitamin D (VitD3) are less permissive to viral replication, and produce lower levels of pro-inflammatory cytokines. Therefore, we here evaluated the extent and kinetics of innate immune responses of DENV-2 infected monocytes differentiated into macrophages in the presence (D3-MDMs) or absence of VitD3 (MDMs). We found that D3-MDMs expressed lower levels of RIG I, Toll-like receptor (TLR)3, and TLR7, as well as higher levels of SOCS-1 in response to DENV-2 infection. D3-MDMs produced lower levels of reactive oxygen species, related to a lower expression of TLR9. Moreover, although VitD3 treatment did not modulate either the expression of IFN-α or IFN-ß, higher expression of protein kinase R (PKR) and 2'-5'-oligoadenylate synthetase 1 (OAS1) mRNA were found in D3-MDMs. Importantly, the observed effects were independent of reduced infection, highlighting the intrinsic differences between D3-MDMs and MDMs. Taken together, our results suggest that differentiation of MDMs in the presence of VitD3 modulates innate immunity in responses to DENV-2 infection.

OAS1/RNase L executes RIG-I ligand-dependent tumor cell apoptosis.

Cytoplasmic double-stranded RNA is sensed by RIG-I-like receptors (RLRs), leading to induction of type I interferons (IFN-Is), proinflammatory cytokines, and apoptosis. Here, we elucidate signaling mechanisms that lead to cytokine secretion and cell death induction upon stimulation with the bona fide RIG-I ligand 5'-triphosphate RNA (3p-RNA) in tumor cells. We show that both outcomes are mediated by dsRNA-receptor families with RLR being essential for cytokine production and IFN-I-mediated priming of effector pathways but not for apoptosis. Affinity purification followed by mass spectrometry and subsequent functional analysis revealed that 3p-RNA bound and activated oligoadenylate synthetase 1 and RNase L. RNase L-deficient cells were profoundly impaired in their ability to undergo apoptosis. Mechanistically, the concerted action of translational arrest triggered by RNase L and up-regulation of NOXA was needed to deplete the antiapoptotic MCL-1 to cause intrinsic apoptosis. Thus, 3p-RNA-induced apoptosis is a two-step process consisting of RIG-I-dependent priming and an RNase L-dependent effector phase.

Heterozygous OAS1 gain-of-function variants cause an autoinflammatory immunodeficiency.

Analysis of autoinflammatory and immunodeficiency disorders elucidates human immunity and fosters the development of targeted therapies. Oligoadenylate synthetase 1 is a type I interferon-induced, intracellular double-stranded RNA (dsRNA) sensor that generates 2'-5'-oligoadenylate to activate ribonuclease L (RNase L) as a means of antiviral defense. We identified four de novo heterozygous OAS1 gain-of-function variants in six patients with a polymorphic autoinflammatory immunodeficiency characterized by recurrent fever, dermatitis, inflammatory bowel disease, pulmonary alveolar proteinosis, and hypogammaglobulinemia. To establish causality, we applied genetic, molecular dynamics simulation, biochemical, and cellular functional analyses in heterologous, autologous, and inducible pluripotent stem cell-derived macrophages and/or monocytes and B cells. We found that upon interferon-induced expression, OAS1 variant proteins displayed dsRNA-independent activity, which resulted in RNase L-mediated RNA cleavage, transcriptomic alteration, translational arrest, and dysfunction and apoptosis of monocytes, macrophages, and B cells. RNase L inhibition with curcumin modulated and allogeneic hematopoietic cell transplantation cured the disorder. Together, these data suggest that human OAS1 is a regulator of interferon-induced hyperinflammatory monocyte, macrophage, and B cell pathophysiology.

Tupaia OASL1 Promotes Cellular Antiviral Immune Responses by Recruiting MDA5 to MAVS.

Melanoma differentiation-associated gene 5 (MDA5) is a key cytoplasmic dsRNA sensor. Upon binding to invading viral RNA, activated MDA5 is recruited to mitochondria and interacts with mitochondrial antiviral signaling gene (MAVS) to initiate innate antiviral immune responses. The elegant regulation of this process remains elusive. In this study, using the Chinese tree shrew (Tupaia belangeri chinensis), which is genetically close to primates, we identified the Tupaia oligoadenylate synthetases-like 1 (tOASL1) as a positive regulator of the Tupaia MDA5 (tMDA5) and Tupaia MAVS (tMAVS)-mediated IFN signaling. Overexpression of tOASL1 significantly potentiated the RNA virus-triggered induction of the type I IFNs and downstream antiviral genes. Conversely, knockdown of tOASL1 had an impaired antiviral immune response. Mechanistically, tOASL1 was associated with mitochondria and directly interacted with tMDA5 and tMAVS. Upon RNA virus infection, tOASL1 enhanced the interaction between tMDA5 and tMAVS via its OAS and UBL domains. Our results revealed a novel mechanism by which tOASL1 contributes to host antiviral responses via enhancing tMDA5 and tMAVS interaction.

Expression of IFN-induced 2'-5'-oligoadenylate synthetases correlates with immune infiltration, revealing potential targets and new biomarkers for basal-like breast cancer prognosis.

Triple-negative breast cancer has been classified as basal-like immune activated (BLIA), basal-like immune-suppressed (BLIS), and two other subtypes, suggesting potential immune therapeutic targets for basal-like breast cancer (BLBC). 2'-5'-Oligoadenylate synthetases (OASs), identified from differentially expressed genes (DEGs) between BLIA and BLIS breast cancers (GSE76124), are involved in antiviral activity induced by interferons. However, the association between the four OASs and prognosis or tumor-infiltrating immune cells (TIICs) remains unclear. Expression, survival data, and immune correlations for OASs in BLBC were assessed using bioinformatics tools. We found that OASs were highly expressed in BLIA breast cancer. Survival analysis suggested that high transcriptional levels of OASs were associated with better overall survival, relapse-free survival, and distant metastasis-free survival in patients with BLBC. Moreover, the prognostic value of OASs with respect to different clinicopathological factors, and especially according to lymph node metastasis, in patients with BLBC was further assessed. Our findings elucidated the expression, prognostic role, and effect of OASs in TIICs on BLBC, which might promote the development of OAS-targeted immunotherapy for BLBC.

2'-5'-Oligoadenylate synthetase-like protein inhibits intracellular M. tuberculosis replication and promotes proinflammatory cytokine secretion.

Host cytoplasmic surveillance pathways are known to elicit type I interferon (IFN) responses which are crucial to antimicrobial defense mechanisms. Oligoadenylate synthetase-like (OASL) protein has been extensively characterized as a part of the anti-viral mechanism, however a number of transcriptomic studies reveal its upregulation in response to infection with a wide variety of intracellular bacterial pathogens. To date, there is no evidence documenting the role (if any) of OASL during mycobacterium tuberculosis infection. Using two pathogenic strains differing in virulence only, as well as the non-pathogenic M. bovis BCG strain, we observed that pathogenicity and virulence strongly induced OASL expression after 24 h of infection. Further, we observed that OASL knock down led to a significant increase in M. tb CFU counts 96 h post-infection in comparison to the respective controls. Luminex revealed that OASL silencing significantly decreased IL-1ß, TNF-α and MCP-1 secretion in THP-1 cells and had no effect on IL-10 secretion. We therefore postulate that OASL regulates pro-inflammatory mediators such as cytokines and chemokines which suppress intracellular mycobacterial growth and survival.

Inhibition of PARP1 Increases IRF-dependent Gene Transcription in Jurkat Cells.

Poly(ADP-ribose) polymerase 1 (PARP1) plays important roles in the regulation of transcription factors. Mounting evidence has shown that inhibition of PARP1 influences the expression of genes associated with inflammatory response. Interferon regulatory factor 1 (IRF1) is a critical transcription factor for the development of both the innate and adaptive immune responses against infections. However, the molecular mechanism through which PARP1 mediates the effects has not been clearly demonstrated. Jurkat cells were exposed to dexamethasone (Dex) or PARP1 inhibitor PJ34. The expression levels of IL-12, LMP2, OAS1 and PKR were detected using real-time RT-PCR. The interactions between PARP1 and IRF1 were examined by co-immunoprecipitation (co-IP) assays. We further explored the mechanism of PARP1 suppressing IRF1 by assessing the activities of interferon stimulated response element (ISRE). The mRNA expression of IL-12, LMP2, OAS1 and PKR was obviously suppressed by Dex in Jurkat cells, which could be rescued by PJ34 treatment. Luciferase study revealed that poly(ADP-ribosyl)- ation suppressed IRF1-mediated transcription through preventing the binding of IRF1 to ISREs. PARP1 inhibited IRF1-mediated transcription in Jurkat cells by preventing IRF1 binding to ISREs in the promoters of target genes. It is suggested that PARP1 is a crucial regulator of IRF1-mediated immune response. This study provides experimental evidence for the possible application of PARP1 inhibitors in the treatment of IRF1-related immune anergy.

Origin and development of oligoadenylate synthetase immune system.

BACKGROUND: Oligoadenylate synthetases (OASs) are widely distributed in Metazoa including sponges, fish, reptiles, birds and mammals and show large variation, with one to twelve members in any given species. Upon double-stranded RNA (dsRNA) binding, avian and mammalian OASs generate the second messenger 2'-5'-linked oligoadenylate (2-5A), which activates ribonuclease L (RNaseL) and blocks viral replication. However, how Metazoa shape their OAS repertoires to keep evolutionary balance to virus infection is largely unknown. We performed comprehensive phylogenetic and functional analyses of OAS genes from evolutionarily lower to higher Metazoa to demonstrate how the OAS repertoires have developed anti-viral activity and diversified their functions. RESULTS: Ancient Metazoa harbor OAS genes, but lack both upstream and downstream genes of the OAS-related pathways, indicating that ancient OASs are not interferon-induced genes involved in the innate immune system. Compared to OASs of ancient Metazoa (i.e. sponge), the corresponding ones of higher Metazoa present an increasing number of basic residues on the OAS/dsRNA interaction interface. Such an increase of basic residues might improve their binding affinity to dsRNA. Moreover, mutations of functional residues in the active pocket might lead to the fact that higher Metazoan OASs lose the ability to produce 3'-5'-linked oligoadenylate (3-5A) and turn into specific 2-5A synthetases. In addition, we found that multiple rounds of gene duplication and domain coupling events occurred in the OAS family and mutations at functionally critical sites were observed in most new OAS members. CONCLUSIONS: We propose a model for the expansion of OAS members and provide comprehensive evidence of subsequent neo-functionalization and sub-functionalization. Our observations lay the foundation for interrogating the evolutionary transition of ancient OAS genes to host defense genes and provide important information for exploring the unknown function of the OAS gene family.

Expression of the OAS Gene Family Is Highly Modulated in Subjects Affected by Juvenile Dermatomyositis, Resembling an Immune Response to a dsRNA Virus Infection.

BACKGROUND: Juvenile dermatomyositis (JDM) is a systemic, autoimmune, interferon (IFN)-mediated inflammatory muscle disorder that affects children younger than 18 years of age. JDM primarily affects the skin and the skeletal muscles. Interestingly, the role of viral infections has been hypothesized. Mammalian 2'-5'-oligoadenylate synthetase (OAS) genes have been thoroughly characterized as components of the IFN-induced antiviral system, and they are connected to several innate immune-activated diseases. The main purpose of the paper is to define the potential interrelationship between the OAS gene family network and the molecular events that characterize JDM along with double-stranded RNA (dsRNA) molecular pathways. METHODS: We analyzed three microarray datasets obtained from the NCBI in order to verify the expression levels of the OAS gene family network in muscle biopsies (MBx) of JDM patients compared to healthy controls. Furthermore, From GSE51392, we decided to select significant gene expression profiles of primary nasal and bronchial epithelial cells isolated from healthy subjects and treated with polyinosinic-polycytidylic acid (poly(I:C)), a synthetic analog of double-stranded RNA (dsRNA), a molecular pattern associated with viral infection. RESULTS: The analysis showed that all OAS genes were modulated in JDM muscle biopsies. Furthermore, 99% of OASs gene family networks were significantly upregulated. Of importance, 39.9% of modulated genes in JDM overlapped with those of primary epithelial cells treated with poly(I:C). Moreover, the microarray analysis showed that the double-stranded dsRNA virus gene network was highly expressed. In addition, we showed that the innate/adaptive immunity markers were significantly expressed in JDM muscles biopsies. and that their levels were positively correlated to OAS gene family expression. CONCLUSION: OAS gene expression is extremely modulated in JDM as well as in the dsRNA viral gene network. These data lead us to speculate on the potential involvement of a viral infection as a trigger moment for this systemic autoimmune disease. Further in vitro and translational studies are needed to verify this hypothesis in order to strategically plan treatment interventions.

RIG-I enhances interferon-α response by promoting antiviral protein expression in patients with chronic hepatitis B.

BACKGROUND: Interferon (IFN)-α is widely used for the treatment of chronic hepatitis B (CHB) infection due to the high rate of hepatitis B surface antigen (HBsAg) seroconversion. However, IFN-α treatment has a number of side effects. Thus, identification of molecular biomarkers to predict IFN-α therapeutic effect would be useful in the clinic. In this study, we aimed to investigate the role of retinoic acid-inducible gene-I (RIG-I) in prediction of IFN-α curative effect of CHB patients. METHODS: A total of 65 CHB patients treated with pegylated IFN-α weekly for 48 weeks were enrolled. Real-time PCR was performed for detection of RIG-I and IFN-stimulated gene (ISG) expression. In vitro, the HepG2 cells were transfected with siRNA and levels of RIG-I and anti-HBV proteins were detected by western blot. The P-values were calculated in SPSS 18.0. The statistical significance level was accepted as P<0.05. RESULTS: In this study, we found RIG-I expression in peripheral blood mononuclear cells was higher in responder than non-responder CHB patients treated with IFN-α therapy. In HBV-transfected HepG2 and Huh7 cells, RIG-I enhanced IFN-α response by promoting anti-HBV protein expression such as double-stranded RNA-dependent protein kinase (PKR), oligoadenylate synthetase (OAS), adenosine deaminase (ADAR1) and Mx protein. Knocking down of RIG-I could downregulate the expression of these proteins. Inhibited RIG-I expression by RIG-I siRNA deceased STAT1 phosphorylation. CONCLUSIONS: Our results revealed RIG-I enhanced IFN-α response by promoting antiviral protein expression via the STAT1 pathway. RIG-I may be a new predictive factor for prediction of IFN-α efficacy in CHB patients.

Evidence that interferon-tau secreted from Day-7 embryo in vivo generates anti-inflammatory immune response in the bovine uterus.

Recent studies suggest that Day-7 bovine embryo starts to communicate with the uterine epithelium through interferon-tau (IFNT) signaling. However, immune modulatory role of IFNT in the uterus just after the embryo moves from the oviduct is unclear. We aimed to examine the hypothesis that Day-7 bovine embryo secretes IFNT in the uterus, which induces anti-inflammatory response in immune cells. The uterine flush (UF) with multiple embryos was collected from Day-7 donor pregnant cows and peripheral blood mononuclear cells (PBMCs) were then cultured in UF. Transcripts detected in PBMCs revealed that UF from pregnant cows down-regulated pro-inflammatory cytokines (TNFA, IL1B) and up-regulated anti-inflammatory cytokine (IL10) expression, with activation of interferon-stimulated genes (ISGs; ISG15, OAS1) as compared with UF from non-pregnant cows. An addition of specific anti-IFNT antibody to the UF inhibited the effect on PBMCs, indicating that IFNT is a major factor for such immune modulation. The observation that conditioned media from bovine uterine epithelial cells both stimulated with IFNT in vitro and supplemented with fresh IFNT induced similar PBMCs gene expression, confirming that IFNT directly acts on this immune crosstalk. This study shows that IFNT secreted from Day-7 embryo in vivo generates anti-inflammatory response in immune cells, which may provide immunological tolerance to accept the embryo.

Myxovirus resistance protein A inhibits hepatitis C virus replication through JAK-STAT pathway activation.

The interferon-inducible dynamin-like GTPase myxovirus resistance protein A (MxA) exhibits activity against multiple viruses. However, its role in the life cycle of hepatitis C virus (HCV) is unclear, and the mechanisms underlying the anti-HCV activity of MxA require further investigation. In this study, we demonstrated that exogenous MxA expression in the Huh7 and Huh7.5.1 hepatoma cell lines significantly decreased the levels of HCV RNA and core proteins, whereas MxA knockdown exerted the opposite effect. MxA-mediated inhibition of HCV replication was found to involve the JAK-STAT pathway: STAT1 phosphorylation and the expression of IFN-stimulated genes (ISGs) such as guanylate-binding protein 1 and 2'-5'-oligoadenylate synthetase 1 were augmented by MxA overexpression and reduced by endogenous MxA silencing. Treatment with the JAK inhibitor ruxolitinib abrogated the MxA-mediated suppression of HCV replication and activation of the JAK-STAT pathway. Additionally, transfection with an MxA mutant with disrupted GTP-binding consensus motifs abrogated activation of the JAK-STAT pathway and resistance to HCV replication. This study shows that MxA inhibits HCV replication by activating the JAK-STAT signaling pathway through a mechanism involving its GTPase function.

OASL1 Traps Viral RNAs in Stress Granules to Promote Antiviral Responses.

Oligoadenylate synthetase (OAS) protein family is the major interferon (IFN)-stimulated genes responsible for the activation of RNase L pathway upon viral infection. OAS-like (OASL) is also required for inhibition of viral growth in human cells, but the loss of one of its mouse homolog, OASL1, causes a severe defect in termination of type I interferon production. To further investigate the antiviral activity of OASL1, we examined its subcellular localization and regulatory roles in IFN production in the early and late stages of viral infection. We found OASL1, but not OASL2, formed stress granules trapping viral RNAs and promoted efficient RLR signaling in early stages of infection. Stress granule formation was dependent on RNA binding activity of OASL1. But in the late stages of infection, OASL1 interacted with IRF7 transcripts to inhibit translation resulting in down regulation of IFN production. These results implicate that OASL1 plays context dependent functions in the antiviral response for the clearance and resolution of viral infections.

Expression of IFN-Inducible Genes with Antiviral Function OAS1 and MX1 in Health and under Conditions of Recurrent Herpes Simplex Infection.

We studied the expression of IFN-inducible genes OAS1 and Mx1 in lysates of peripheral blood mononuclear cells from patients suffering from recurrent Herpes simplex infections in comparison with healthy people. To induce the expression of the studied genes, blood mononuclears were incubated with recombinant IFN-α2b in concentrations of 1, 10, and 100 U/ml for 3 h and then the content of the studied transcripts was evaluated. Relative expression of OAS1 and Mx1 in patients with recurrent forms of Herpes simplex both during the acute stage and clinical remission did not differ significantly from that in healthy people after stimulation with IFN-α2b in a concentration of 1 U/ml and in higher concentrations (10 and 100 U/ml). It was concluded that intracellular signal transduction in IFN-α-activated cells in vitro was not disturbed in patients with recurrent forms of Herpes simplex infection. Thus, the reported phenomenon of IFN-signalling distortion by Herpes simplex virus proteins observed in experiments on model cell lines infected with Herpes simplex virus was not confirmed in our experiments on peripheral blood mononuclear cells from patients with Herpes simplex infection.

Molecular cloning, characterization, and expression of duck 2'-5'-oligoadenylate synthetase-like gene.

2'-5'-Oligoadenylate synthetase-like protein (OASL) is an interferon-inducible antiviral protein that exerts antiviral effects through the RNase L- or retinoic acid-inducible gene I (RIG-I)-dependent signalling pathway. In this study, we identified and cloned the OASL gene (named duOASL) from healthy adult Cherry Valley ducks. Full-length duOASL cDNA (1630bp) encoded a 504-amino acid polypeptide containing three conserved domains, namely, nucleotidyltransferase domain, 2'-5'-oligoadenylate synthetase domain, and two ubiquitin-like repeats. DuOASL mRNA expression was quantified by performing quantitative reverse transcription-PCR (qRT-PCR). Results of qRT-PCR showed that duOASL was broadly expressed in all examined tissues, with the highest mRNA expression in the large intestine. Antiviral activity of duOASL was measured by determining its effect on Duck Tembusu virus (DTMUV) replication in vitro. We found that duOASL overexpression slightly inhibited DTMUV replication, whereas duOASL knockdown by using a specific small interfering RNA increased DTMUV replication in DF-1 cells. Thus, we successfully cloned and characterized the antiviral protein duOASL from Cherry Valley ducks and found that it exerted antiviral effects against DTMUV. These results provide a solid foundation for performing further studies to determine the mechanism underlying the antiviral effect of duOASL at the cellular level.

The Association of OASL and Type I Interferons in the Pathogenesis and Survival of Intracellular Replicating Bacterial Species.

The type I IFN response quickly became associated with its role in the innate immune response to viral infection. The past few years have seen the significance of IFNs expand in breadth to include non-viral pathogens. Previous work has identified that following viral infection, type I IFN signaling induces the production of the 2'-5'-oligoadenylate synthetase (OAS) family, which include OAS1, OAS2, OAS3, and OAS-like (OASL) protein. OASL was identified to be strongly induced following viral infection through engaging the RNA sensor RIG-I and increasing signaling through this pathway to enhance the anti-viral type I IFN response. Surprisingly, infection with viral dsDNA revealed an IFN inhibitory role and therefore pro-viral function of OASL through the inhibition of the cGAS cytosolic DNA sensing mechanism. Intracellular bacteria are able to activate the cytosolic DNA sensing pathway, however the role of OASL during bacterial infection is largely unknown. Vacuolar pathogenic microbes such as mycobacteria induce OASL early post infection, where it functions in a prosurvival fashion by inhibiting autophagic mechanisms and antimicrobial peptide expression. This suggests an underestimated role of OASL in the innate immune response to infection with a variety of pathogens and points to OASL-associated modulation of the type I IFN response. OASL may therefore play a critical role in defining the outcome of infection. We provide a brief update on the recent developments of the OAS family of proteins in response to DNA and RNA virus infections, as well as discuss evidence of Oasl expression in response to a number of cytosolic and vacuolar replicating bacterial pathogens.

Mitochondrial C11orf83 is a potent Antiviral Protein Independent of interferon production.

Mitochondria have a central position in innate immune response via the adaptor protein MAVS in mitochondrial outer membrane to limit viral replication by inducing interferon production. Here, we reported that C11orf83, a component of complex III of electronic transfer chain in mitochondrial inner membrane, was a potent antiviral protein independent of interferon production. C11orf83 expression significantly increased in response to viral infection, and endows cells with stronger capability of inhibiting viral replication. Deletion of C11orf83 permits viral replication easier and cells were more vulnerable to viral killing. These effects mainly were mediated by triggering OAS3-RNase L system. C11orf83 overexpression induced higher transcription of OAS3, and knockdown either OAS3 or RNase L impaired the antiviral capability of C11orf83. Interestingly, the signaling from C11orf83 to OAS3-RNase L was independent of interferon production. Thus, our findings suggested a new antiviral mechanism by bridging cell metabolic machinery component with antiviral effectors.

Soybean-derived Bowman-Birk Inhibitor (BBI) Inhibits HIV Replication in Macrophages.

The Bowman-Birk inhibitor (BBI), a soybean-derived protease inhibitor, is known to have anti-inflammatory effect in both in vitro and in vivo systems. Macrophages play a key role in inflammation and immune activation, which is implicated in HIV disease progression. Here, we investigated the effect of BBI on HIV infection of peripheral blood monocyte-derived macrophages. We demonstrated that BBI could potently inhibit HIV replication in macrophages without cytotoxicity. Investigation of the mechanism(s) of BBI action on HIV showed that BBI induced the expression of IFN-ß and multiple IFN stimulated genes (ISGs), including Myxovirus resistance protein 2 (Mx2), 2',5'-oligoadenylate synthetase (OAS-1), Virus inhibitory protein (viperin), ISG15 and ISG56. BBI treatment of macrophages also increased the expression of several known HIV restriction factors, including APOBEC3F, APOBEC3G and tetherin. Furthermore, BBI enhanced the phosphorylation of IRF3, a key regulator of IFN-ß. The inhibition of IFN-ß pathway by the neutralization antibody to type I IFN receptor (Anti-IFNAR) abolished BBI-mediated induction of the anti-HIV factors and inhibition of HIV in macrophages. These findings that BBI could activate IFN-ß-mediated signaling pathway, initialize the intracellular innate immunity in macrophages and potently inhibit HIV at multiple steps of viral replication cycle indicate the necessity to further investigate BBI as an alternative and cost-effective anti-HIV natural product.

Reduced sputum expression of interferon-stimulated genes in severe COPD.

BACKGROUND: Exacerbations of COPD are frequent and commonly triggered by respiratory tract infections. The purpose of our study was to investigate innate immunity in stable COPD patients. METHODS: Induced sputum was collected from 51 stable consecutive COPD patients recruited from the COPD Clinic of CHU Liege and 35 healthy subjects. Expression of interferons beta (IFN-ß) and lambda1 (IL-29), IFN-stimulated genes (ISGs) MxA, OAS, and viperin were measured in total sputum cells by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The presence of Picornaviruses was assessed by RT-PCR, while potential pathogenic microorganisms (PPM) were identified by sputum bacteriology. RESULTS: Expression of IL-29 was found in 16 of 51 COPD patients (31%) and in nine of 35 healthy subjects (26%), while IFN-ß was detected in six of 51 COPD patients (12%) and in two of 35 healthy subjects (6%). ISGs were easily detectable in both groups. In the whole group of COPD patients, OAS expression was decreased (P<0.05), while that of viperin was increased (P<0.01) compared to healthy subjects. No difference was found with respect to MxA. COPD patients from group D of Global Initiative for Chronic Obstructive Lung Disease (GOLD) had reduced expression of all three ISGs (P<0.01 for MxA, P<0.05 for OAS, and P<0.01 for viperin) as compared to those of group B patients. Picornaviruses were detected in eight of 51 (16%) COPD patients vs four of 33 (12%) healthy subjects, while PPM were detected in seven of 39 (18%) COPD patients and associated with raised sputum neutrophil counts. IFN-ß expression was raised when either picornavirus or PPM were detected (P=0.06), but no difference was seen regarding IL-29 or ISGs. CONCLUSION: ISGs expression was reduced in severe COPD that may favor exacerbation and contribute to disease progress by altering response to infection.