Induction of MxA gene expression by influenza A virus requires type I or type III interferon signaling

Expression of MxA in esophageal cancer cell lines can influence sensitivity to chemotherapeutic agents but this does not require apoptosis

Esophageal cancer is a poor prognosis cancer characterized by intrinsic or acquired resistance to chemotherapeutic agents. The primary determinants of treatment failure are unknown. Expression of an anti-viral protein, myxovirus resistance protein A (MxA) is de-regulated in many cancers, including esophageal cancer, and its activity has been linked to apoptosis. This study has assessed whether MxA expression can influence the response of esophageal cancer cells to the chemotherapeutic agents 5-fluorouracil (5-FU) or oxaliplatin. MxA protein was differentially expressed in a panel of five esophageal cancer cell lines. KYSE450 and KYSE140 cells did not express MxA and were apoptosis incompetent. FLO-1, KYSE270, and OE21 cells expressed MxA, were more drug-sensitive and were apoptosis competent. MxA was artificially overexpressed in cell lines with no endogenous expression (KYSE450 and KYSE140). This increased the resistance of KYSE450 but not KYSE140 cells. Both cell lines remained apoptosis incompetent. We then evaluated siRNA knockdown of MxA in FLO-1 cells and CRISPR knockout in OE21 cells. Knockdown of MxA significantly increased drug sensitivity and caspase-3 activation in FLO-1 cells. OE21-MX1KO cells were also more drug-sensitive, but in contrast to FLO-1 cells, caspase-3 activation was reduced. Collectively these data indicate that MxA can promote resistance to chemotherapy, but this does not always correspond with effects on apoptosis. Effects on apoptosis are cell line specific, suggesting that other co-operating pathways determine the overall impact of MxA. Importantly, in cancer cells that overexpress the protein, drug sensitivity can be improved by interfering with MxA.

Altered expression of human myxovirus resistance protein A in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder. The etiology of sporadic ALS (sALS) has not yet been clarified. An increasing body of evidence suggests the involvement of viral infections and interferons (IFNs). Human myxovirus resistance protein A (MxA) is an IFN-induced dynamin-like GTPase that acts as a potent antiviral factor. This study examined MxA expression in ALS patient spinal cords using immunohistochemistry. Thirty-two cases of sALS (pathologically proven ALS-TDP), 10 non-ALS, other neurological disease control cases were examined. In most ALS cases, MxA cytoplasmic condensates were observed in the remaining spinal anterior horn neurons. The ALS group had a significantly higher rate of MxA-highly expressing neurons than the non-ALS group. Colocalization of MxA cytoplasmic condensate and transactive response DNA-binding protein 43 kDa (TDP-43)-positive inclusions was rarely observed. Because MxA has antiviral activity induced by IFNs, our results suggest that IFNs are involved in the pathogenesis of ALS in spinal cord anterior horn neurons. Our study also suggests that monitoring viral infections and IFN activation in patients with ALS may be critically important.

Interferon-I modulation and natural products: Unraveling mechanisms and therapeutic potential in severe COVID-19

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to pose a significant global public health threat, particularly to older adults, pregnant women, and individuals with underlying chronic conditions. Dysregulated immune responses to SARS-CoV-2 infection are believed to contribute to the progression of COVID-19 in severe cases. Previous studies indicates that a deficiency in type I interferon (IFN-I) immunity accounts for approximately 15 %-20 % of patients with severe pneumonia caused by COVID-19, highlighting the potential therapeutic importance of modulating IFN-I signals. Natural products and their derivatives, due to their structural diversity and novel scaffolds, play a crucial role in drug discovery. Some of these natural products targeting IFN-I have demonstrated applications in infectious diseases and inflammatory conditions. However, the immunomodulatory potential of IFN-I in critical COVID-19 pneumonia and the natural compounds regulating the related signal pathway remain not fully understood. In this review, we offer a comprehensive assessment of the association between IFN-I and severe COVID-19, exploring its mechanisms and integrating information on natural compounds effective for IFN-I regulation. Focusing on the primary targets of IFN-I, we also summarize the regulatory mechanisms of natural products, their impact on IFNs, and their therapeutic roles in viral infections. Collectively, by synthesizing these findings, our goal is to provide a valuable reference for future research and to inspire innovative treatment strategies for COVID-19.

Antiviral activity of bovine type III interferon against bovine viral diarrhea virus is greatly reduced in bovine turbinate cells due to limited expression of IFN lambda receptor 1 (IL-28Rα)

Introduction

The antiviral activity of recombinant bovine interferon lambda 3 (bovIFN-λ3) against bovine viral diarrhea virus (BVDV) has been demonstrated in vitro in Madin-Darby bovine kidney cells (MDBK) and in vivo in cattle. However, anti-BVDV activity of bovIFN-λ3 has not been studied in bovine respiratory tract epithelial cells, supposedly a primary target of BVDV infection when entering the host by the oronasal route.

Methods

Here we investigated the anti-BVDV activity of bovIFN-λ3 in bovine turbinate-derived primary epithelial cells (BTu) using BVDV infection and immunoperoxidase staining, TCID50, RT-qPCR, DNA and transcriptome sequencing, and transfection with plasmids containing the two subunits, IL-28Rα and IL-10Rβ that constitute the bovIFN-λ3 receptor.

Results

Our immunoperoxidase staining, RT-qPCR, and TCID50 results show that while BVDV was successfully cleared in MDBK cells treated with bovIFN-λ3 and bovIFN-α, only the latter, bovIFN-α, cleared BVDV in BTu cells. Preincubation of MDBK cells with bovIFN-λ3 before BVDV infection was needed to induce optimal antiviral state. Both cell types displayed intact type I and III IFN signaling pathways and expressed similar levels of IL-10Rβ subunit of the type III IFN receptor. Sequencing of PCR amplicon of the IL-28Rα subunit revealed intact transmembrane domain and lack of single nucleotide polymorphisms (SNPs) in BTu cells. However, RT-qPCR and transcriptomic analyses showed a lower expression of IL-28Rα transcripts in BTu cells as compared to MDBK cells. Interestingly, transfection of BTu cells with a plasmid encoding IL-28Rα subunit, but not IL-10Rβ subunit, established the bovIFN-λ3 sensitivity showing similar anti-BVDV activity to the response in MDBK cells.

Conclusion

Our results demonstrate that the sensitivity of cells to bovIFN-λ3 depends not only on the quality but also of the quantity of the IL-28Rα subunit of the heterodimeric receptor. A reduction in IL-28Rα transcript expression was detected in BTu as compared to MDBK cells, despite the absence of spliced variants or SNPs. The establishment of bovIFN-λ3 induced anti-BVDV activity in BTu cells transfected with an IL-28Rα plasmid suggests that the level of expression of this receptor subunit is crucial for the specific antiviral activity of type III IFN in these cells.

Damage sensing through TLR9 Regulates Inflammatory and Antiviral Responses During Influenza Infection

Host response aimed at eliminating the infecting pathogen, as well as the pathogen itself, can cause tissue injury. Tissue injury leads to the release of a myriad of cellular components including mitochondrial DNA, which the host senses through pattern recognition receptors. How the sensing of tissue injury by the host shapes the anti-pathogen response remains poorly understood. In this study, we utilized mice that are deficient in toll-like receptor-9 (TLR9), which binds to unmethylated CpG DNA sequences such as those present in bacterial and mitochondrial DNA. To avoid direct pathogen sensing by TLR9, we utilized the influenza virus, which lacks ligands for TLR9, to determine how damage sensing by TLR9 contributes to anti-influenza immunity. Our data show that TLR9-mediated sensing of tissue damage promotes an inflammatory response during early infection, driven by the epithelial and myeloid cells. Along with the diminished inflammatory response, the absence of TLR9 led to impaired viral clearance manifested as a higher and prolonged influenza components in myeloid cells including monocytes and macrophages rendering them highly inflammatory. The persistent inflammation driven by infected myeloid cells led to persistent lung injury and impaired recovery in influenza-infected TLR9-/- mice. Further, we show elevated TLR9 activation in the plasma samples of patients with influenza and its association with the disease severity in hospitalized patients, demonstrating its clinical relevance. Overall, we demonstrate an essential role of damage sensing through TLR9 in promoting anti-influenza immunity and inflammatory response.

Development of rhesus macaque astrocyte cell lines supporting infection with a panel of viruses

Non-human primate (NHP)-based model systems are highly relevant for biomedical research. However, only few NHP cell lines are available and the generation of additional cell lines is an urgent need to help in the refinement and replacement of these models. Using lentiviral transduction of c-Fos, we established cell lines from the brain of rhesus macaques (Macaca mulatta). Transcriptome analysis revealed that these cell lines are closely related to astrocytes, which was confirmed by immunoblot and immunofluorescence microscopy detecting expression of the astrocyte marker glial fibrillary acidic protein (GFAP). Quantitative real-time PCR (qRT-PCR) demonstrated that major pathways of the interferon (IFN) system are intact. Using retroviral pseudotypes we found that the cell lines are susceptible to entry driven by the glycoproteins of vesicular stomatitis virus (VSV), lymphocytic choriomeningitis virus (LCMV) and to a lesser extent influenza A virus (IAV). Finally, these cells supported growth of Zika virus (ZIKV) and Papiine alphaherpesvirus 2 (PaHV2). In summary, we developed IFN-responsive cell lines from the rhesus macaque brain that allowed entry driven by several viral glycoproteins and were permissive to infection with ZIKV and a primate simplexvirus. These cell lines will be useful for efforts to analyze neurotropic viral infections in rhesus macaque models.

Oral Antiviral Defense: Saliva- and Beverage-like Hypotonicity Dynamically Regulate Formation of Membraneless Biomolecular Condensates of Antiviral Human MxA in Oral Epithelial Cells

The oral mucosa represents a defensive barrier between the external environment and the rest of the body. Oral mucosal cells are constantly bathed in hypotonic saliva (normally one-third tonicity compared to plasma) and are repeatedly exposed to environmental stresses of tonicity, temperature, and pH by the drinks we imbibe (e.g., hypotonic: water, tea, and coffee; hypertonic: assorted fruit juices, and red wines). In the mouth, the broad-spectrum antiviral mediator MxA (a dynamin-family large GTPase) is constitutively expressed in healthy periodontal tissues and induced by Type III interferons (e.g., IFN-λ1/IL-29). Endogenously induced human MxA and exogenously expressed human GFP-MxA formed membraneless biomolecular condensates in the cytoplasm of oral carcinoma cells (OECM1 cell line). These condensates likely represent storage granules in equilibrium with antivirally active dispersed MxA. Remarkably, cytoplasmic MxA condensates were exquisitely sensitive sensors of hypotonicity-the condensates in oral epithelium disassembled within 1-2 min of exposure of cells to saliva-like one-third hypotonicity, and spontaneously reassembled in the next 4-7 min. Water, tea, and coffee enhanced this disassembly. Fluorescence changes in OECM1 cells preloaded with calcein-AM (a reporter of cytosolic "macromolecular crowding") confirmed that this process involved macromolecular uncrowding and subsequent recrowding secondary to changes in cell volume. However, hypertonicity had little effect on MxA condensates. The spontaneous reassembly of GFP-MxA condensates in oral epithelial cells, even under continuous saliva-like hypotonicity, was slowed by the protein-phosphatase-inhibitor cyclosporin A (CsA) and by the K-channel-blocker tetraethylammonium chloride (TEA); this is suggestive of the involvement of the volume-sensitive WNK kinase-protein phosphatase (PTP)-K-Cl cotransporter (KCC) pathway in the regulated volume decrease (RVD) during condensate reassembly in oral cells. The present study identifies a novel subcellular consequence of hypotonic stress in oral epithelial cells, in terms of the rapid and dynamic changes in the structure of one class of phase-separated biomolecular condensates in the cytoplasm-the antiviral MxA condensates. More generally, the data raise the possibility that hypotonicity-driven stresses likely affect other intracellular functions involving liquid-liquid phase separation (LLPS) in cells of the oral mucosa.

Increased expression of human antiviral protein MxA in FUS proteinopathy in amyotrophic lateral sclerosis

FUS mutations are one of the major mutations in familial amyotrophic lateral sclerosis (ALS). The pathological hallmark is FUS-positive neuronal cytoplasmic inclusions (FUS-NCI), known as FUS proteinopathy. Human myxovirus resistance protein 1 (MxA) is an IFN-induced dynamin-like GTPase that acts as antiviral factor. In this study, we examined the expression of MxA in neurons bearing FUS-NCI. We performed immunohistochemistry for FUS and MxA to examine the expression of MxA in two autopsy cases with different FUS gene mutations localized at the nuclear localization signal site (Case 1, H517P; Case 2, R521C). MxA. Most neurons bearing FUS-NCI have increased cytoplasmic MxA expression. Increased cytoplasmic MxA showed several distribution patterns in relation to FUS-NCIs such as the following: colocalization with NCI, distribution more widely than NCI, and different distribution peaks from NCI. Our results suggested that antiviral signaling IFNs are involved upstream in the formation of FUS-NCI in ALS-FUS patients.

Bioinformatics analysis of competing endogenous RNA network in decidual natural killer cell from unexplained recurrent spontaneous abortion

BACKGROUND

Decidual natural killer (dNK) cell plays a pivotal role in maintaining pregnancy, especially in the first trimester. Noncoding-RNAs (ncRNAs) are critical regulators of transcription and protein expression. Dysregulation of ncRNAs may be involved in the pathogenesis of unexplained recurrent spontaneous abortion (URSA). However, the role of competing endogenous RNA (ceRNA) based on mRNA-miRNA-lncRNA network in regulating the incidence and progression of URSA remains elusive. The aim of the study is to identify the regulatory network of mRNA-miRNA-LncRNA ceRNA based on bioinformatics analysis in dNK from patients with URSA.

METHODS

Eligible studies were retrieved from PubMed, Embase, and the Gene Expression Omnibus (GEO) databases to identify differentially expressed genes (DEGs), miRNAs and LncRNAs in dNK cells of patients with URSA. Protein-protein interaction (PPI) network was constructed by STRING database and Cytoscape software. Potential regulatory miRNAs and lncRNAs of mRNAs were predicted by miRTarBase and RNA22 and subject to bioinformatics analysis.

RESULTS

A total of 634 DEGs were screened, including 290 upregulated and 344 downregulated DEGs. Among 207 differentially expressed lncRNAs, 110 lncRNAs were upregulated and 97 were downregulated. According to node degree, 30 hub genes were identified for subsequent research. After drawing the Venn diagram and matching to Cytoscape, an mRNA-miRNA-lncRNA network linked to the pathogenesis of URSA in dNK cells was constructed.

CONCLUSIONS

A novel regulatory network of mRNA-miRNA-lncRNA ceRNA is established in dNK cells from patients with URSA. All RNAs might be used as the biomarkers of the pathogenesis of URSA.

Comparison of media for a human peripheral blood mononuclear cell-based in vitro vaccine evaluation system

Purpose

Human peripheral blood mononuclear cell (PBMC)-based in vitro systems can be of great value in the development and assessment of vaccines but require the right medium for optimal performance of the different cell types present. Here, we compare three commonly used media for their capacity to support innate and adaptive immune responses evoked in PBMCs by Toll-like receptor (TLR) ligands and whole inactivated virus (WIV) influenza vaccine.

Materials and Methods

Human PBMCs were cultured for different periods of time in Roswell Park Memorial Institute (RPMI), Dulbecco's minimal essential medium (DMEM), or Iscove's modified DMEM (IMDM) supplemented with 10% fetal calf serum. The viability of the cells was monitored and their responses to TLR ligands and WIV were assessed.

Results

With increasing days of incubation, the viability of PBMCs cultured in RPMI or IMDM was slightly higher than that of cells cultured in DMEM. Upon exposure of the PBMCs to TLR ligands and WIV, RPMI was superior to the other two media in terms of supporting the expression of genes related to innate immunity, such as the TLR adaptor protein gene MyD88 (myeloid differentiation factor 88), the interferon (IFN)-stimulated genes MxA (myxovirus resistance protein 1) and ISG56 (interferon-stimulated gene 56), and the leukocyte recruitment chemokine gene MCP1 (monocyte chemoattractant protein-1). RPMI also performed best with regard to the activation of antigen-presenting cells. As for adaptive immunity, when stimulated with WIV, PBMCs cultured in RPMI or IMDM contained higher numbers of IFNγ-producing T cells and secreted more immunoglobulin G than PBMCs cultured in DMEM.

Conclusion

Taken together, among the different media assessed, RPMI was identified as the optimal medium for a human PBMC-based in vitro vaccine evaluation system.

A type I interferon footprint in pre-operative biopsies is an independent biomarker that in combination with CD8+ T cell quantification can improve the prediction of response to neoadjuvant treatment of rectal adenocarcinoma

Tailored treatment for patients with rectal cancer requires clinically available markers to predict their response to neoadjuvant treatment. The quantity of tumor-infiltrating lymphocytes (TILs) in pre-operative tumor biopsies has been suggested to predict a favorable response, but opposing results exist. A biopsy-adapted Immunoscore (ISB) based on TILs has recently emerged as a promising predictor of tumor regression and prognosis in (colo)rectal cancer. We aimed to refine the ISB for prediction of response using multiplex immunofluorescence (mIF) on pre-operative rectal cancer biopsies. We combined the distribution and density of conventional T cell subsets and γδT cells with a type I Interferon (IFN)-driven response assessed using Myxovirus resistance protein A (MxA) expression. We found that pathological complete response (pCR) following neoadjuvant treatment was associated with type I IFN. Stratification of patients according to the density of CD8+ in the entire tumor tissue and MxA+ cells in tumor stroma, where equal weight was assigned to both parameters, resulted in improved predictive quality compared to the ISB. This novel stratification approach using these two independent parameters in pre-operative biopsies could potentially aid in identifying patients with a good chance of achieving a pCR following neoadjuvant treatment.

5-Ethynyluridine: A Bio-orthogonal Uridine Variant for mRNA-Based Therapies and Vaccines

The identification of pseudo- and N¹ -methylpseudo-uridine (Ψ and mΨ, respectively) as immunosilent uridine analogues has propelled the development of mRNA-based vaccines and therapeutics. Here, we have characterised another uridine analogue, 5-ethynyluridine (EU), which has an ethynyl moiety. We show that this uridine analogue does not cause immune activation in human macrophages, as it does not induce interleukin-6 secretion or expression of the inflammatory and antiviral genes MX1, PKR, and TAP2. Moreover, EU allows for prolonged expression, as shown with mRNA coding for yellow fluorescent protein (YFP). Side-by-side comparisons of EU with unmodified, Ψ, and mΨ revealed that EU-modified mRNA is expressed at lower levels, but confers similar stability and low immunogenicity to the other uridine analogues. Furthermore, structure analysis of modified mRNAs suggests that the observed phenotype is largely independent of RNA folding. Thus, EU is a potential candidate for RNA-based vaccines and therapeutics.

In Vitro and In Vivo Characterization of H5N8 High-Pathogenicity Avian Influenza Virus Neurotropism in Ducks and Chickens

H5N8 high-pathogenicity avian influenza virus (HPAIV) of clade 2.3.4.4B, which circulated during the 2016 epizootics in Europe, was notable for causing different clinical signs in ducks and chickens. The clinical signs preceding death were predominantly neurological in ducks versus respiratory in chickens. To investigate the determinants for the predominant neurological signs observed in ducks, we infected duck and chicken primary cortical neurons. Viral replication was identical in neuronal cultures from both species. In addition, we did not detect any major difference in the immune and inflammatory responses. These results suggest that the predominant neurological involvement of H5N8 HPAIV infection in ducks could not be recapitulated in primary neuronal cultures. In vivo, H5N8 HPAIV replication in ducks peaked soon after infection and led to an early colonization of the central nervous system. In contrast, viral replication was delayed in chickens but ultimately burst in the lungs of chickens, and the chickens died of respiratory distress before brain damage became significant. Consequently, the immune and inflammatory responses in the brain were significantly higher in duck brains than those in chickens. Our study thus suggests that early colonization of the central nervous system associated with prolonged survival after the onset of virus replication is the likely primary cause of the sustained inflammatory response and subsequent neurological disorders observed in H5N8 HPAIV-infected ducks. IMPORTANCE The severity of high-pathogenicity avian influenza virus (HPAIV) infection has been linked to its ability to replicate systemically and cause lesions in a variety of tissues. However, the symptomatology depends on the host species. The H5N8 virus of clade 2.3.4.4B had a pronounced neurotropism in ducks, leading to severe neurological disorders. In contrast, neurological signs were rarely observed in chickens, which suffered mostly from respiratory distress. Here, we investigated the determinants of H5N8 HPAIV neurotropism. We provide evidence that the difference in clinical signs was not due to a difference in neurotropism. Our results rather indicate that chickens died of respiratory distress due to intense viral replication in the lungs before viral replication in the brain could produce significant lesions. In contrast, ducks better controlled virus replication in the lungs, thus allowing the virus to replicate for a sufficient duration in the brain, to reach high levels, and to cause significant lesions.

LncRNA EN-90756 promotes CPB2-induced proliferation and inhibits apoptosis in IPEC-J2 cells by affecting the JAK-STAT signaling pathway activation

Background

Long non-coding RNAs (lncRNAs), as key regulators, are closely associated with the development of a variety of disease. However, the mechanisms by which lncRNAs regulate Clostridium perfringens type C induced piglet diarrhea are unclear.

Methods

In the present study, we explored the expression and characterization of lncRNAs in a C. perfringens beta2 (CPB2) toxin-treated intestinal porcine epithelial cell line-J2 (IPEC-J2) using RNA-sequencing (RNA-seq).

Results

A total of 6,558 lncRNAs were identified, of which 49 lncRNAs were significantly differentially expressed between the control and CPB2 groups. Functional enrichment analysis showed that the target genes of differentially expressed lncRNA EN-90756 were mainly associated with defense response to virus, and negative regulation of apoptotic process. LncRNA EN-90756 was significantly up-regulated in IPEC-J2 cells at different time points after CPB2 treatment. Functionally, knockdown of lncRNA EN-90756 might regulate the proliferation and apoptosis of IPEC-J2 cells by affecting the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway. LncRNA EN-90756 may be involved in CPB2 toxin-induced piglet diarrhea by regulating the expression of its target gene MX1 (encoding MX dynamin like GTPase 1).

Conclusion

Long non-coding RNA EN-90756 affected the antiviral ability of IPEC-J2 cells by regulating the expression of MX1. Meanwhile, lncRNA EN-90756 might regulate cell proliferation and apoptosis by affecting JAK-STAT signaling pathway activation. These findings provide novel perspectives and directions for further exploration of the regulatory mechanisms of lncRNAs on CPB2 toxin-induced diarrhea in piglets.

Development of immortalized rhesus macaque kidney cells supporting infection with a panel of viruses

Non-human primate (NHP)-based model systems faithfully reproduce various viral diseases including Ebola, influenza, AIDS and Zika. However, only a small number of NHP cell lines are available and generation of additional cell lines could help to refine these models. We immortalized rhesus macaque kidney cells by lentiviral transduction with a vector encoding telomerase reverse transcriptase (TERT) and report the generation of three TERT-immortalized cell lines derived from rhesus macaque kidney. Expression of the kidney podocyte marker podoplanin on these cells was demonstrated by flow cytometry. Quantitative real-time PCR (qRT-PCR) was employed to demonstrate induction of MX1 expression upon stimulation with interferon (IFN) or viral infection, suggesting a functional IFN system. Further, the cell lines were susceptible to entry driven by the glycoproteins of vesicular stomatitis virus, influenza A virus, Ebola virus, Nipah virus and Lassa virus as assessed by infection with retroviral pseudotypes. Finally, these cells supported growth of Zika virus and the primate simplexviruses Cercopithecine alphaherpesvirus 2 and Papiine alphaherpesvirus 2. In summary, we developed IFN-responsive rhesus macaque kidney cell lines that allowed entry driven by diverse viral glycoproteins and were permissive to infection with Zika virus and primate simplexviruses. These cell lines will be useful for efforts to analyze viral infections of the kidney in macaque models.

Pestiviruses infection: Interferon-virus mutual regulation

Pestiviruses are a class of viruses that in some cases can cause persistent infection of the host, thus posing a threat to the livestock industry. Interferons (IFNs) are a group of secreted proteins that play a crucial role in antiviral defense. In this review, on the one hand, we elaborate on how pestiviruses are recognized by the host retinoic acid-inducible gene-I (RIG-I), melanoma-differentiation-associated protein 5 (MDA5), and Toll-like receptor 3 (TLR3) proteins to induce the synthesis of IFNs. On the other hand, we focus on reviewing how pestiviruses antagonize the production of IFNs utilizing various strategies mediated by self-encoded proteins, such as the structural envelope protein (E^rns) and non-structural protein (N^pro). Hence, the IFN signal transduction pathway induced by pestiviruses infection and the process of pestiviruses blockade on the production of IFNs intertwines into an intricate regulatory network. By reviewing the interaction between IFN and pestiviruses (based on studies on BVDV and CSFV), we expect to provide a theoretical basis and reference for a better understanding of the mechanisms of induction and evasion of the innate immune response during infection with these viruses.

Unraveling the Link between Interferon-α and Systemic Lupus Erythematosus: From the Molecular Mechanisms to Target Therapies

Systemic lupus erythematosus (SLE) is a chronic, systemic autoimmune disease with a wide range of clinical expressions. The kidney is often affected, usually within 5 years of the onset of SLE, and lupus nephropathy (LN) carries a high risk for increased morbidity. The clinical heterogeneity of the disease is accompanied by complex disturbances affecting the immune system with inflammation and tissue damage due to loss of tolerance to nuclear antigens and the deposition of immune complexes in tissues. Several studies have reported that in human SLE, there is an important role of the Type-I-interferons (INF) system suggested by the upregulation of INF-inducible genes observed in serial gene expression microarray studies. This review aims to describe the transduction pathways of Type-I-interferons, in particular INFα, and its immune-regulatory function in the pathogenesis of SLE and, in particular, in LN. In addition, recent novelties concerning biologic therapy in LN will be discussed.

A Report of 2 Cases of Kidney Involvement in ADA2 Deficiency: Different Disease Phenotypes and the Tissue Response to Type I Interferon

Adenosine deaminase 2 (ADA2) deficiency is a rare autosomal recessive disease that is caused by loss-of-function mutations in the ADA2 gene. It is considered a monogenic form of polyarteritis nodosa and frequently is positive for a type I interferon (IFN) signature. Renal manifestations in ADA2 deficiency are poorly characterized. We herein report 2 cases of ADA2 deficiency with different kidney patterns due, respectively, to a predominantly macroscopic and microscopic vasculopathy, and review the literature on kidney disease in ADA2 deficiency. Patient 1 presented with a spontaneous perirenal hematoma; angiography demonstrated multiple microaneurysms but no further defects of the renal parenchyma; his kidney function remained normal. Patient 2 experienced slowly deteriorating kidney function and proteinuria. No major angiographic abnormalities were detected, while kidney biopsy revealed massive vasculopathy resembling chronic thrombotic microangiopathy (TMA) of the small and medium-sized vessels. Both patients had a positive peripheral type I IFN signature. In immunofluorescence staining of a kidney biopsy sample from patient 2, we observed marked expression of the type I IFN-induced protein MXA within endothelial cells, especially in vessels with TMA, and in infiltrating T cells. Our findings confirm that the kidney phenotype of ADA2 deficiency results from small and medium-sized vessel vasculopathy and suggest that type I IFN may be involved in the pathogenesis of kidney lesions.

The involvement of an interferon-induced protein 44-like (CgIFI44L) in the antiviral immune response of Crassostrea gigas

Interferon-stimulated genes (ISGs) encoding proteins are the essential executors of interferon (IFN) mediated antiviral defense. In the present study, an ISG member, interferon-induced protein 44-like (IFI44L) gene (designed as CgIFI44L-1) was identified from the Pacific oyster Crassostrea gigas. The ORF of CgIFI44L-1 cDNA was of 1437 bp encoding a polypeptide of 479 amino acids with a TLDc domain and an MMR_HSR1 domain. The mRNA transcripts of CgIFI44L-1 were detected in all the tested tissues with highest level in haemocytes, which was 15.78-fold of that in gonad (p < 0.001). Among the haemocytes, the CgIFI44L-1 protein was detected to be highly expressed in granulocytes with dominant distribution in cytoplasm. The mRNA expression level of CgIFI44L-1 in haemocytes was significantly induced by poly (I:C) stimulation, and the expression level peaked at 24 h, which was 24.24-fold (p < 0.0001) of that in control group. After the treatment with the recombinant protein of an oyster IFN-like protein (rCgIFNLP), the mRNA expression level of CgIFI44L-1 was significantly enhanced at 6 h, 12 h and 24 h, which was 2.67-fold (p < 0.001), 5.44-fold (p < 0.001) and 5.16-fold (p < 0.001) of that in control group, respectively. When the expressions of CgSTAT and CgIFNLP were knocked down by RNA interference (RNAi), the mRNA transcripts of CgIFI44L-1 were significantly down-regulated after poly (I:C) stimulation, which was 0.09-fold (p < 0.001) and 0.06-fold (p < 0.001) of those in EGFP group, respectively. These results suggested that CgIFI44L-1 was a conserved ISG in oyster, which was regulated by CgIFNLP and CgSTAT, and involved in the oyster antiviral immune response.

Association of human myxovirus resistance protein A with severity of COVID-19

Background

In this retrospective cohort study, we explored the correlation of blood human myxovirus resistance protein A (MxA) level with severity of disease in hospitalized COVID-19 patients.

Methods

All 304 patients admitted for COVID-19 in our hospital until 30th of April 2021 were included in this study. MxA was measured from peripheral blood samples in 268 cases. Patients were divided into groups based on their level of MxA on admission. We studied baseline characteristics and severity of disease on admission based on clinical parameters and inflammatory biomarker levels in each group. Severity of disease during hospitalization was determined by the applied level of respiratory support, by the usage of corticosteroids and by the duration of hospitalization.

Results

Higher MxA levels on admission were associated with a shorter duration of symptoms before admission, and with more severe disease. Adjusted Odds Ratios for any respiratory support were 9.92 (95%CI 2.11–46.58; p = 0.004) in patients with MxA between 400 μg/L and 799 μg/L (p = 0.004) and 20.08 (95%CI 4.51–89.44; p < 0.001) in patients with MxA ≥ 800 μg/L in comparison with patients with initial MxA < 400 μg/L. The usage of corticosteroids was significantly higher in the high-MxA group (77%) in comparison with the intermediate-MxA group (62%, p = 0.013) and low-MxA group (47%, p < 0.001).

Conclusions

Higher initial levels of MxA were associated with more severe COVID-19. MxA may be a helpful additional biomarker to predict the severity of the disease.

CD24 Expression Dampens the Basal Antiviral State in Human Neuroblastoma Cells and Enhances Permissivity to Zika Virus Infection

Zika virus (ZIKV) exhibits distinct selectivity for infection of various cells and tissues, but how host cellular factors modulate varying permissivity remains largely unknown. Previous studies showed that the neuroblastoma cell line SK-N-AS (expressing low levels of cellular protein CD24) was highly restricted for ZIKV infection, and that this restriction was relieved by ectopic expression of CD24. We tested the hypothesis that CD24 expression allowed ZIKV replication by suppression of the antiviral response. SK-N-AS cells expressing an empty vector (termed CD24-low cells) showed elevated basal levels of phosphorylated STAT1, IRF-1, IKKE, and NFκB. In response to exogenously added type I interferon (IFN-I), CD24-low cells had higher-level induction of antiviral genes and activity against two IFN-I-sensitive viruses (VSV and PIV5-P/V) compared to SK-N-AS cells with ectopic CD24 expression (termed CD24-high cells). Media-transfer experiments showed that the inherent antiviral state of CD24-low cells was not dependent on a secreted factor such as IFN-I. Transcriptomics analysis revealed that CD24 expression decreased expression of genes involved in intracellular antiviral pathways, including IFN-I, NFκB, and Ras. Our findings that CD24 expression in neuroblastoma cells represses intracellular antiviral pathways support the proposal that CD24 may represent a novel biomarker in cancer cells for susceptibility to oncolytic viruses.

The Interferon-Inducible Human PLSCR1 Protein Is a Restriction Factor of Human Cytomegalovirus

Human phospholipid scramblase 1 (PLSCR1) is strongly expressed in response to interferon (IFN) treatment and viral infection, and it has been suggested to play an important role in IFN-dependent antiviral responses. In this study, we showed that the levels of human cytomegalovirus (HCMV) plaque formation in OUMS-36T-3 (36T-3) cells with high basal expression of PLSCR1 were significantly lower than those in human embryonic lung (HEL) cells with low basal expression of PLSCR1. In addition, the levels of HCMV plaque formation and replication in PLSCR1-knockout (KO) 36T-3 cells were significantly higher than those in parental 36T-3 cells and were comparable to those in HEL cells. Furthermore, compared to that in PLSCR1-KO cells, the expression of HCMV major immediate early (MIE) proteins was repressed and/or delayed in parental 36T-3 cells after HCMV infection. We also showed that PLSCR1 expression decreased the levels of the cAMP-responsive element (CRE)-binding protein (CREB)•HCMV immediate early protein 2 (IE2) and CREB-binding protein (CBP)•IE2 complexes, which have been suggested to play important roles in the IE2-mediated transactivation of the viral early promoter through interactions with CREB, CBP, and IE2. Interestingly, PLSCR1 expression repressed CRE- and HCMV MIE promoter-regulated reporter gene activities. These observations reveal, for the first time, that PLSCR1 negatively regulates HCMV replication by repressing the transcription from viral MIE and early promoters, and that PLSCR1 expression may contribute to the IFN-mediated suppression of HCMV infection. IMPORTANCE Because several IFN-stimulated genes (ISGs) have been reported to suppress HCMV replication, HCMV replication is thought to be regulated by an IFN-mediated host defense mechanism, but the mechanism remains unclear. PLSCR1 expression is induced in response to viral infection and IFN treatment, and PLSCR1 has been reported to play an important role in IFN-dependent antiviral responses. Here, we demonstrate that HCMV plaque formation and major immediate early (MIE) gene expression are significantly increased in PLSCR1-KO human fibroblast cells. PLSCR1 reduces levels of the CREB•IE2 and CBP•IE2 complexes, which have been suggested to play important roles in HCMV replication through its interactions with CREB, CBP, and IE2. In addition, PLSCR1 expression represses transcription from the HCMV MIE promoter. Our results indicate that PLSCR1 plays important roles in the suppression of HCMV replication in the IFN-mediated host defense system.

Myxovirus Resistance Protein A as a Marker of Viral Cause of Illness in Children Hospitalized with an Acute Infection

A biomarker for viral infection could improve the differentiation between viral and bacterial infections and reduce antibiotic overuse. We examined blood myxovirus resistance protein A (MxA) as a biomarker for viral infections in children with an acute infection. We recruited 251 children presenting with a clinical suspicion of serious bacterial infection, determined by need for a blood bacterial culture collection, and 14 children with suspected viral infection at two pediatric emergency departments. All children were aged between 4 weeks and 16 years. We classified cases according to the viral, bacterial, or other etiology of the final diagnosis. The ability of MxA to differentiate between viral and bacterial infections was assessed. The median blood MxA levels were 467 (interquartile range, 235 to 812) μg/L in 39 children with a viral infection, 469 (178 to 827) μg/L in 103 children with viral-bacterial coinfection, 119 (68 to 227) μg/L in 75 children with bacterial infection, and 150 (101 to 212) μg/L in 26 children with bacterial infection and coincidental virus finding (P < 0.001). In a receiver operating characteristics analysis, MxA cutoff level of 256 μg/L differentiated between children with viral and bacterial infections with an area under the curve of 0.81 (95% confidence interval [CI] = 0.73 to 0.90), a sensitivity of 74.4%, and a specificity of 80.0%. In conclusion, MxA protein showed moderate accuracy as a biomarker for symptomatic viral infections in children hospitalized with an acute infection. High prevalence of viral-bacterial coinfections supports the use of MxA in combination with biomarkers of bacterial infection.

IMPORTANCE Due to the diagnostic uncertainty concerning the differentiation between viral and bacterial infections, children with viral infections are often treated with antibiotics, predisposing them to adverse effects and contributing to the emerging antibiotic resistance. Since currently available biomarkers only estimate the risk of bacterial infection, a biomarker for viral infection is needed in attempts of reducing antibiotic overuse. Blood MxA protein, which has broad antiviral activity and is rapidly induced in acute, symptomatic viral infections, is a potential biomarker for viral infection. In this diagnostic study of 265 children hospitalized because of an acute infection, blood MxA cutoff level of 256 μg/L discriminated between viral and bacterial infections with a sensitivity of 74% and specificity of 80%. MxA could improve the differential diagnostics of febrile children at the emergency department but, because of frequently detected viral-bacterial coinfections, a combination with biomarkers of bacterial infection may be needed.

Opposite Outcomes of the Within-Host Competition between High- and Low-Pathogenic H5N8 Avian Influenza Viruses in Chickens Compared to Ducks

Highly pathogenic avian influenza viruses (HPAIV) emerge from low-pathogenic avian influenza viruses (LPAIV) through the introduction of basic amino acids at the hemagglutinin (HA) cleavage site. Following viral evolution, the newly formed HPAIV likely represents a minority variant within the index host, predominantly infected with the LPAIV precursor. Using reverse genetics-engineered H5N8 viruses differing solely at the HA cleavage, we tested the hypothesis that the interaction between the minority HPAIV and the majority LPAIV could modulate the risk of HPAIV emergence and that the nature of the interaction could depend on the host species. In chickens, we observed that the H5N8LP increased H5N8HP replication and pathogenesis. In contrast, the H5N8LP antagonized H5N8HP replication and pathogenesis in ducks. Ducks mounted a more potent antiviral innate immune response than chickens against the H5N8LP, which correlated with H5N8HP inhibition. These data provide experimental evidence that HPAIV may be more likely to emerge in chickens than in ducks and underscore the importance of within-host viral variant interactions in viral evolution. IMPORTANCE Highly pathogenic avian influenza viruses represent a threat to poultry production systems and to human health because of their impact on food security and because of their zoonotic potential. It is therefore crucial to better understand how these viruses emerge. Using a within-host competition model between high- and low-pathogenic avian influenza viruses, we provide evidence that highly pathogenic avian influenza viruses could be more likely to emerge in chickens than in ducks. These results have important implications for highly pathogenic avian influenza virus emergence prevention, and they underscore the importance of within-host viral variant interactions in virus evolution.

Cancer-specific type-I interferon receptor signaling promotes cancer stemness and effector CD8+ T-cell exhaustion

Type-I interferon (IFN-I) signaling is critical to maintaining antigen-presenting cell function for anti-tumor immunity. However, recent studies have suggested that IFN-I signaling may also contribute to more aggressive phenotypes, raising the possibility that IFN-I downstream signaling in cancer and myeloid cells may exert dichotomous functions.We analyzed the clinicopathologic correlation of cancer-specific IFN-I activation in 195 head and neck squamous cell carcinoma patients. We also characterized the immune impact of IFN-I receptor (IFNAR1)-deficiency in syngeneic tumor models using biochemistry, flow cytometry, and single-cell RNA-Seq. We stained HNSCC tissue microarrays with a sensitive IFN-I downstream signaling activation marker, MX1, and quantitated cancer cell-specific MX1 staining. Kaplan-Meier analysis revealed that MX1-high tumors exhibited worse survival, a phenotype that depends on the number of CD8⁺ intratumoral T-cells. We found that cancer-specific IFNAR1 engagement promotes cancer stemness and higher expression levels of suppressive immune checkpoint receptor ligands in cancer-derived exosomes. Notably, mice bearing Ifnar1-deficient tumors exhibited lower tumor burden, increased T-cell infiltration, reduced exhausted CD4⁺PD1^high T-cells, and increased effector population CD8⁺IFN-γ⁺ T-cells. Then, we performed single-cell RNA-sequencing and discovered that cancer-specific IFN-I signaling not only restricts effector cells expansion but also dampens their functional fitness.The beneficial role of IFN-I activation is largely dependent on the myeloid compartment. Cancer-specific IFN-I receptor engagement promotes cancer stemness and the release of cancer-derived exosomes with high expression levels of immune checkpoint receptor ligands. Cancer-specific IFN-I activation is associated with poor immunogenicity and worse clinical outcomes in HNSCC.

A myxovirus resistance like protein involved in CgIFNLP mediated immune response of oyster Crassostrea gigas

The myxovirus resistance (Mx) proteins belong to interferon (IFN)-induced dynamin GTPase and play a pivotal role in the inhibition of replication of numerous viruses. In the present study, an Mx homologue (designated as CgMx1) was identified from oyster Crassostrea gigas. The open reading frame (ORF) of CgMx1 cDNA was of 1689 bp encoding a peptide of 562 amino acid residues. There was an N-terminal dynamin GTPase domain in the predicted peptide, which consisted of a tripartite GTP-binding motif (GDXXSGKS, DLPG and T/NKXD). The deduced amino acid sequence of CgMx1 shared 30-39% similarity with other Mx family members. And CgMx1 was clustered with Mx from H. discus, and then assigned into the invertebrate branch of the phylogenetic tree. The mRNA transcripts of CgMx1 were constitutively distributed in all the tested tissues, with the highest level in haemocytes (1342.45-fold of labial palps, p < 0.05). The mRNA expression of CgMx1 in haemocytes was significantly up-regulated to the highest level at 6 h (13.14-fold, p < 0.001) after poly (I:C) treatment and at 24 h (66.28-fold, p < 0.001) after recombinant IFN-like protein (rCgIFNLP) stimulation, respectively. CgMx1 protein was found to distribute in both the cytoplasm and nucleus of haemocytes. In the oysters with CgIFNLP and signal transducer and activator of transcription (CgSTAT) silenced by RNAi, the mRNA expression of CgMx1 decreased significantly in the haemocytes at 12 h after poly (I:C) stimulation, which was 0.02-fold and 0.04-fold of that in EGFP-RNAi oysters (p < 0.001), respectively. Meanwhile, EMSA assay revealed that CgSTAT was able to transactivate CgMx1 promoter through directly binding to its interferon-stimulated response element (ISRE) and gamma interferon activation site (GAS). The above results indicated that CgMx1 participated in the immune response of C. gigas through the signal pathway mediated by CgIFNLP and CgSTAT.

Intranasal type I interferon treatment is beneficial only when administered before clinical signs onset in the SARS-CoV-2 hamster model

Impaired type I interferons (IFNs) production or signaling have been associated with severe COVID-19, further promoting the evaluation of recombinant type I IFNs as therapeutics against SARS-CoV-2 infection. In the Syrian hamster model, we show that intranasal administration of IFN-α starting one day pre-infection or one day post-infection limited weight loss and decreased viral lung titers. By contrast, intranasal administration of IFN-α starting at the onset of symptoms three days post-infection had no impact on the clinical course of SARS-CoV-2 infection. Our results provide evidence that early type I IFN treatment is beneficial, while late interventions are ineffective, although not associated with signs of enhanced disease.

Type I interferons are major antiviral effectors produced by the host in response to viral infections. Importantly, delayed or impaired type I IFN signalling response has been shown to correlate with severe COVID-19. These observations provided further impetus to test the administration of exogenous type I IFN as a treatment against SARS-CoV-2 infection in patients. However, studies using MERS-CoV or SARS-CoV infected mice demonstrated that type I interferon treatment was beneficial when administered early, but was ineffective and even caused deleterious immunopathology when administered at later stages of infection. It is therefore crucial to understand how the timing of the type I IFN treatments modulates their efficacy and safety against SARS-CoV-2. In this preclinical study using the SARS-CoV-2-infected Syrian hamster model, we showed that intranasal type I IFN treatment was beneficial only when administered before the onset of symptoms. Importantly, late treatment was ineffective but was not associated with deleterious effects. This study provides important information to interpret clinical trials showing no to modest effects of type I IFNs in COVID-19 patients.

Effects of Bacillus cereus PAS38 on Immune-Related Differentially Expressed Genes of Spleen in Broilers

This study mainly explored the immunomodulatory mechanisms of the probiotic Bacillus cereus PAS38 (PB) on broiler spleen. A total of 120 avian white feather broilers were randomly divided into 4 groups (N = 30), as follows: control (CNTL, fed with basal diet), PB (fed with diet supplemented with probiotic B. cereus PAS38), vaccine (VAC, fed with basal diet and injected with Newcastle disease virus vaccine), and vaccine + PB group (PBVAC, fed with basal diet supplemented with B. cereus PAS38 and injected with NDV vaccine). The experiment was conducted for 42 days. Twelve spleens were collected from four different groups, weighed, and cut into histological sections, and transcriptome analysis was performed using RNA-seq. Results of the spleen and histological section relative weights showed that feeding with probiotic B. cereus PAS38 and vaccination had a similar tendency to promote spleen development. Compared with the CNTL group, 21 immune-related genes were significantly downregulated in the PB and PBVAC groups. These genes were mainly involved in attenuating inflammatory response. The upregulated antimicrobial peptide NK-lysin and guanylate-binding protein 1 expression levels indicated that this strain enhanced the body's antimicrobial capacity. B. cereus PAS38 also amplified the broilers' immune response to the vaccine, which mainly reflected on nonspecific immunity. Hence, probiotic B. cereus PAS38 can regulate and promote the immune function of broilers.

Cytoplasmic-translocated Ku70 senses intracellular DNA and mediates interferon-lambda1 induction

We have previously identified that human Ku70, a nuclear protein, serves as a cytosolic DNA sensor. Upon transfection with DNA or infection with DNA virus, Ku70 translocates from the nucleus into the cytoplasm and then predominately induces interferon lambda1 (IFN-λ1) rather than IFN-alpha or IFN-beta, through a STING-dependent signalling pathway. However, a detailed mechanism for Ku70 cytoplasmic translocation and its correlation with IFN-λ1 induction have not been fully elucidated. Here, we observed that cytoplasmic translocation of Ku70 only occurred in DNA-triggered IFN-λ1-inducible cells. Additionally, infection by Herpes simplex virus type-1 (HSV-1), a DNA virus, induces cytoplasmic translocation of Ku70 and IFN-λ1 induction in a strain-dependent manner: the translocation and IFN-λ1 induction were detected upon infection by HSV-1 McKrae, but not MacIntyre, strain. A kinetic analysis indicated that cytoplasmic translocation of Ku70 was initiated right after DNA transfection and was peaked at 6 hr after DNA stimulation. Furthermore, treatment with leptomycin B, a nuclear export inhibitor, inhibited both Ku70 translocation and IFN-λ1 induction, suggesting that Ku70 translocation is an essential and early event for its cytosolic DNA sensing. We further confirmed that enhancing the acetylation status of the cells promotes Ku70's cytoplasmic accumulation, and therefore increases DNA-mediated IFN-λ1 induction. These findings provide insights into the molecular mechanism by which the versatile sensor detects pathogenic DNA in a localization-dependent manner.

Paracrine IFN Response Limits ZIKV Infection in Human Sertoli Cells

Zika virus (ZIKV) is unique among mosquito-borne flaviviruses in its ability to be sexually transmitted. The testes have been implicated as sites of long-term ZIKV replication, and our previous studies have identified Sertoli cells (SC), the nurse cells of the seminiferous epithelium that govern spermatogenesis, as major targets of ZIKV infection. To improve our understanding of the interaction of ZIKV with human SC, we analyzed ZIKV-induced proteome changes in these cells using high-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS). Our data demonstrated that interferon (IFN) signaling was the most significantly enriched pathway and the antiviral proteins MX1 and IFIT1 were among the top upregulated proteins in SC following ZIKV infection. The dynamic between IFN response and ZIKV infection kinetics in SC remains unclear, therefore we further determined whether MX1 and IFIT1 serve as antiviral effectors against ZIKV. We found that increased levels of MX1 at the later time points of infection coincided with diminished ZIKV infection while the silencing of MX1 and IFIT1 enhanced peak ZIKV propagation in SC. Furthermore, although IFN-I exposure was found to significantly hinder ZIKV replication in SC, IFN response was attenuated in these cells as compared to other cell types. The data in this study highlight IFN-I as a driver of the antiviral state that limits ZIKV infection in SC and suggests that MX1 and IFIT1 function as antiviral effectors against ZIKV in SC. Collectively, this study provides important biological insights into the response of SC to ZIKV infection and the ability of the virus to persist in the testes.

Collapsing Glomerulopathy as a Complication of Type I Interferon-Mediated Glomerulopathy in a Patient With RNASEH2B-Related Aicardi-Goutières Syndrome

Aicardi-Goutières syndrome (AGS) is a well-characterized monogenic type I interferonopathy presenting with prominent neurologic manifestations. Among extraneurologic features, renal involvement has been described in only 1 patient with an IFIH1 mutation in whom membranous nephropathy developed. The pathogenic role of augmented interferon (IFN) signaling in tissues other than the central nervous system remains to be elucidated. We report a case of collapsing glomerulopathy in a 15-year-old girl affected by AGS with RNASEH2B mutation (an alanine-to-threonine change at amino acid 177), which led to kidney failure. The patient had no lupus-like features and lacked the APOL1 G1 and G2 risk alleles. Kidney biopsy showed findings consistent with collapsing glomerulopathy. MxA, a protein involved in antiviral immunity and induced by type I IFNs, was selectively expressed in CD133-positive parietal epithelial cells (PECs) but not in podocytes that stained for synaptopodin or in other glomerular cells. MxA also colocalized within pseudocrescents with CD44, a marker of PEC activation involved in cellular proliferation, differentiation, and migration and in glomerular scarring. Our findings suggest that collapsing glomerulopathy can be a complication of the type I interferonopathy AGS and that a constitutively enhanced type I IFN response in CD133-positive PECs can drive collapsing glomerulopathy.

Organic synthesis and anti-influenza A virus activity of cyclobakuchiols A, B, C, and D

Novel antiviral agents for influenza, which poses a substantial threat to humans, are required. Cyclobakuchiols A and B have been isolated from Psoralea glandulosa, and cyclobakuchiol C has been isolated from P. corylifolia. The structural differences between cyclobakuchiol A and C arise due to the oxidation state of isopropyl group, and these compounds can be derived from (+)-(S)-bakuchiol, a phenolic isoprenoid compound present in P. corylifolia seeds. We previously reported that bakuchiol induces enantiospecific anti-influenza A virus activity involving nuclear factor erythroid 2-related factor 2 (Nrf2) activation. However, it remains unclear whether cyclobakuchiols A–C induce anti-influenza A virus activity. In this study, cyclobakuchiols A, B, and C along with cyclobakuchiol D, a new artificial compound derived from cyclobakuchiol B, were synthesized and examined for their anti-influenza A virus activities using Madin-Darby canine kidney cells. As a result, cyclobakuchiols A–D were found to inhibit influenza A viral infection, growth, and the reduction of expression of viral mRNAs and proteins in influenza A virus-infected cells. Additionally, these compounds markedly reduced the mRNA expression of the host cell influenza A virus-induced immune response genes, interferon-β and myxovirus-resistant protein 1. In addition, cyclobakuchiols A–D upregulated the mRNA levels of NAD(P)H quinone oxidoreductase 1, an Nrf2-induced gene, in influenza A virus-infected cells. Notably, cyclobakuchiols A, B, and C, but not D, induced the Nrf2 activation pathway. These findings demonstrate that cyclobakuchiols have anti-influenza viral activity involving host cell oxidative stress response. In addition, our results suggest that the suitably spatial configuration between oxidized isopropyl group and phenol moiety in the structure of cyclobakuchiols is required for their effect.

Mammalian and Avian Host Cell Influenza A Restriction Factors

The threat of a new influenza pandemic is real. With past pandemics claiming millions of lives, finding new ways to combat this virus is essential. Host cells have developed a multi-modular system to detect incoming pathogens, a phenomenon called sensing. The signaling cascade triggered by sensing subsequently induces protection for themselves and their surrounding neighbors, termed interferon (IFN) response. This response induces the upregulation of hundreds of interferon-stimulated genes (ISGs), including antiviral effectors, establishing an antiviral state. As well as the antiviral proteins induced through the IFN system, cells also possess a so-called intrinsic immunity, constituted of antiviral proteins that are constitutively expressed, creating a first barrier preceding the induction of the interferon system. All these combined antiviral effectors inhibit the virus at various stages of the viral lifecycle, using a wide array of mechanisms. Here, we provide a review of mammalian and avian influenza A restriction factors, detailing their mechanism of action and in vivo relevance, when known. Understanding their mode of action might help pave the way for the development of new influenza treatments, which are absolutely required if we want to be prepared to face a new pandemic.

Interferon antagonism by SARS-CoV-2: a functional study using reverse genetics

Background

The COVID-19 agent, SARS-CoV-2, is conspecific with SARS-CoV, the causal agent of the severe acute respiratory syndrome epidemic in 2002–03. Although the viruses share a completely homologous repertoire of proteins and use the same cellular entry receptor, their transmission efficiencies and pathogenetic traits differ. We aimed to compare interferon antagonism by SARS-CoV and SARS-CoV-2.

Methods

For this functional study, we infected Vero E6 and Calu-3 cells with strains of SARS-CoV and SARS-CoV-2. We studied differences in cell line-specific replication (Vero E6 vs Calu-3 cells) and analysed these differences in relation to TMPRSS2-dependent cell entry based on inhibition with the drug camostat mesilate. We evaluated viral sensitivity towards type I interferon treatment and assessed cytokine induction and type I interferon signalling in the host cells by RT-PCR and analysis of transcription factor activation and nuclear translocation. Based on reverse genetic engineering of SARS-CoV, we investigated the contribution of open reading frame 6 (ORF6) to the observed phenotypic differences in interferon signalling, because ORF6 encodes an interferon signalling antagonist. We did a luciferase-based interferon-stimulated response element promotor activation assay to evaluate the antagonistic capacity of SARS-CoV-2 wild-type ORF6 constructs and three mutants (Gln51Glu, Gln56Glu, or both) that represent amino acid substitutions between SARS-CoV and SARS-CoV-2 protein 6 in the carboxy-terminal domain.

Findings

Overall, replication was higher for SARS-CoV in Vero E6 cells and for SARS-CoV-2 in Calu-3 cells. SARS-CoV-2 was reliant on TMPRSS2, found only in Calu-3 cells, for more efficient entry. SARS-CoV-2 was more sensitive to interferon treatment, less efficient in suppressing cytokine induction via IRF3 nuclear translocation, and permissive of a higher level of induction of interferon-stimulated genes MX1 and ISG56. SARS-CoV-2 ORF6 expressed in the context of a fully replicating SARS-CoV backbone suppressed MX1 gene induction, but this suppression was less efficient than that by SARS-CoV ORF6. Mutagenesis showed that charged amino acids in residues 51 and 56 shift the phenotype towards more efficient interferon antagonism, as seen in SARS-CoV.

Interpretation

SARS-CoV-2 ORF6 interferes less efficiently with human interferon induction and interferon signalling than SARS-CoV ORF6. Because of the homology of the genes, onward selection for fitness could involve functional optimisation of interferon antagonism. Charged amino acids at positions 51 and 56 in ORF6 should be monitored for potential adaptive changes.

Funding

Bundesministerium für Bildung und Forschung, EU RECOVER project.

Expression profiles of interferon-related genes in cells infected with influenza A viruses or transiently transfected with plasmids encoding viral RNA polymerase

Influenza A viruses frequently change their genetic characteristics, which leads to the emergence of new viruses. Consequently, elucidation of the relationship between influenza A virus and host cells has a great importance to cope with viral infections. In this study, it was aimed to determine expression profiles of interferon response genes in human embryonic kidney 293 (HEK293) cells infected with human (A/WSN-H1N1) and avian influenza A viruses (duck/Pennsylvania/10218/84/H5N2) or transfected with plasmids encoding viral RdRP subunits and, to obtain clues about the genes that may be important for the viral pathogenesis. The HEK293 cells cultured in a 12-well plate were infected with influenza A viruses or transfected with plasmids encoding viral polymerase. Total RNA extraction and cDNA preparation were carried out with commercial kits. Qiagen 96-well-RT² Profiler PCR Array plates designated for interferons response genes were used for quantitation of the transcripts. The relative quantities of transcripts were normalized with STAT3 gen, and the results were evaluated. Quantitative RT-PCR results showed that there are substantial differences of the interferon response gene transcription in cells infected with viruses or transfected with plasmids. A higher number of interferon-related genes were found to be downregulated in the cells infected with DkPen compared to WSN. On the other hand, significant differences in the expression profiles of interferon response genes were observed in the cells expressing viral PA protein. In particular, avian influenza PA protein was found to cause more aggressive changes on the transcript levels. Human and avian influenza A viruses cause a substantial change in interferon response gene expression in HEK293 cells. However, a higher number of genes were downregulated in the cells infected with avian influenza DkPen compared to WSN. It has been also concluded that the viral PA protein is one of the important viral factors affecting the transcript level of host genes.

A Novel Cell-based In vitro Assay for Antiviral Activity of Interferons α, β, and γ by qPCR of MxA Gene Expression

BACKGROUND

Human MxA gene is related to the class of interferon (IFN)-stimulated genes (ISGs) that plays a role in antiviral resistance.

OBJECTIVE

Implementation of standard curves obtained from designing a procedure for data processing in relative qPCR between MxA expression and interferon's antiviral activity (IU/ml). These standard curves can be used to detect the antiviral activity of any new compound rapidly and safely.

METHODS

To detect the optimum incubation time for maximum MxA gene expression in human peripheral blood mononuclear cells (PBMC), the isolated human PBMCs (1x106 cells) were incubated with a concentration of 1000 IU/ml of each IFN at different time intervals; 2 h, 4 h, 6 h, and 24 h post-treatment. A standard curve was performed for each IFN (α, β, and γ) at different concentrations (250, 500, 750, 1000, 1500, and 2000 IU/ml).

RESULTS

As observed at 4 h incubation time of 1000 IU/ml concentration, IFN-γ provided a higher expression of MxA compared to IFN-α and IFN-β. Correlation analyses between IFN-α and IFN-β, IFN-β and IFN-γ were non-significant. However, there was a significant correlation between IFN-α and IFN-γ (p<0.01). Receiver operator characteristic (ROC) analysis revealed that cut-off values of IFN- γ, IFN-β, and IFN-α were 58.14 > 7.31 and > 3.33, respectively.

CONCLUSIONS

The relative expression of MxA is a biomarker for IFN-α, β, and γ, especially IFN-α. It has compiled and validated a standard curve-based protocol for PCR data processing. It shows that the standard curve is an easy alternative tool to assess antiviral activity. We revised all patents relating to the antiviral assays of the used interferons.

Machine learning algorithms reveal unique gene expression profiles in muscle biopsies from patients with different types of myositis

OBJECTIVES

Myositis is a heterogeneous family of diseases that includes dermatomyositis (DM), antisynthetase syndrome (AS), immune-mediated necrotising myopathy (IMNM), inclusion body myositis (IBM), polymyositis and overlap myositis. Additional subtypes of myositis can be defined by the presence of myositis-specific autoantibodies (MSAs). The purpose of this study was to define unique gene expression profiles in muscle biopsies from patients with MSA-positive DM, AS and IMNM as well as IBM.

METHODS

RNA-seq was performed on muscle biopsies from 119 myositis patients with IBM or defined MSAs and 20 controls. Machine learning algorithms were trained on transcriptomic data and recursive feature elimination was used to determine which genes were most useful for classifying muscle biopsies into each type and MSA-defined subtype of myositis.

RESULTS

The support vector machine learning algorithm classified the muscle biopsies with >90% accuracy. Recursive feature elimination identified genes that are most useful to the machine learning algorithm and that are only overexpressed in one type of myositis. For example, CAMK1G (calcium/calmodulin-dependent protein kinase IG), EGR4 (early growth response protein 4) and CXCL8 (interleukin 8) are highly expressed in AS but not in DM or other types of myositis. Using the same computational approach, we also identified genes that are uniquely overexpressed in different MSA-defined subtypes. These included apolipoprotein A4 (APOA4), which is only expressed in anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) myopathy, and MADCAM1 (mucosal vascular addressin cell adhesion molecule 1), which is only expressed in anti-Mi2-positive DM.

CONCLUSIONS

Unique gene expression profiles in muscle biopsies from patients with MSA-defined subtypes of myositis and IBM suggest that different pathological mechanisms underly muscle damage in each of these diseases.

SNW1 interacts with IKKγ to positively regulate antiviral innate immune responses against influenza A virus infection

The Ski-interacting protein (SNW1) acts as a transcriptional co-regulator associated with mRNA splicing and transcription, cell cycle progression, acute and chronic inflammatory responses, however, its role involved in host antiviral innate immune responses remains to be explored. Here, for the first time, we demonstrated that SNW1 positively regulates the expression of pro-inflammatory cytokines and interferon (IFN) responses induced by influenza A virus (IAV) infection, and further inhibits virus replication by performing SNW1 depletion or overexpression approaches. Furthermore, we showed that reduced interferon beta (IFN-β) expression caused by interfering SNW1 impairs the activation of JAK-STAT pathway in response to IAV or poly I:C. Importantly, by interacting with IKKγ, the regulatory subunit of IκB kinase (IKK) complex, SNW1 promotes IAV-induced activation of NF-κB and phosphorylation of TBK1 kinase, leading to the increase of antiviral effectors interleukin 6 (IL-6), C-X-C motif chemokine 10 (CXCL10), IFN-β and myxovirus resistance protein 1 (MX1). Taken together, our study revealed that SNW1 is an important mediator of host defenses against IAV through the induction of pro-inflammatory factors and IFN signaling, providing novel insights in modulating innate immune responses to protect host from IAV infection.

Zinc Finger CCCH-Type Antiviral Protein 1 Restricts the Viral Replication by Positively Regulating Type I Interferon Response

Zinc finger CCCH-type antiviral protein 1 (ZC3HAV1) is a host antiviral factor that can repress translation and promote degradation of specific viral mRNAs. In this study, we found that expression of ZC3HAV1 was significantly induced by infection with influenza A virus (IAV) and Sendai virus (Sev). It was shown that deficiency of IFNAR resulted in a dramatic decrease in the virus-induced expression of ZC3HAV1. Furthermore, transfection with poly(I:C) and treatment with interferon β (IFN-β) induced the ZC3HAV1 expression. Interference with the endogenous expression of ZC3HAV1 enhanced the replication of influenza virus by impairing the production of IFN-β and MxA, following the infection of influenza virus. In contrast, ectopic expression of ZC3HAV1 significantly restricted the replication of influenza virus by increasing the IFN-β expression. In addition, ZC3HAV1 also promoted the induction of tumor necrosis factor and interleukin 6. These results suggest that ZC3HAV1 is induced by IFN-β/IFNAR signaling during IAV and Sev infection and involved in positive regulation of IFN-dependent innate antiviral response.

The pros and cons of interferons for oncolytic virotherapy

Interferons (IFN) are potent immune stimulators that play key roles in both innate and adaptive immune responses. They are considered the first line of defense against viral pathogens and can even be used as treatments to boost the immune system. While viruses are usually seen as a threat to the host, an emerging class of cancer therapeutics exploits the natural capacity of some viruses to directly infect and kill cancer cells. The cancer-specificity of these bio-therapeutics, called oncolytic viruses (OVs), often relies on defective IFN responses that are frequently observed in cancer cells, therefore increasing their vulnerability to viruses compared to healthy cells. To ensure the safety of the therapy, many OVs have been engineered to further activate the IFN response. As a consequence of this IFN over-stimulation, the virus is cleared faster by the immune system, which limits direct oncolysis. Importantly, the therapeutic activity of OVs also relies on their capacity to trigger anti-tumor immunity and IFNs are key players in this aspect. Here, we review the complex cancer-virus-anti-tumor immunity interplay and discuss the diverse functions of IFNs for each of these processes.

Type I Interferon Regulates the Survival and Functionality of B Cells in Rainbow Trout

Interferons (IFNs) orchestrate antiviral responses in jawed vertebrates and can be classified into three types based on different aspects of their genomic organization, structure and receptors through which they signal and function. Generally, type I and type III IFNs include cytokines that directly induce an antiviral response, whereas type II IFNs are well-known for their immunomodulatory role during viral infections. In mammals, type I IFNs have been shown to also regulate many aspects of B cell development and differentiation. Yet, these functions have been only faintly investigated for teleost IFNs. Thus, in the current study, we have examined the effects of a model type I rainbow trout IFN molecule (IFNa) on blood naïve (IgM⁺IgD⁺) B cells, comparing them to those exerted by type II IFN (IFNγ). Our results demonstrate that IFNa increases the survival of naïve rainbow trout B cells, in the absence of lymphoproliferative effects, by rescuing them from spontaneous apoptosis. Additionally, IFNa increased the phagocytic capacity of blood IgM⁺IgD⁺ B cells and augmented the number of IgM-secreting cells in blood leukocyte cultures. IFNγ, on the other hand, had only minor effects up-regulating IgM secretion, whereas it increased the phagocytic capacity of IgM⁻ cells in the cultures. Finally, given the recent identification of 9 mx genes in rainbow trout, we have also established which of these genes were transcriptionally regulated in blood naïve B cells in response to IFNa. This study points to a previously undescribed role for teleost type I IFNs in the regulation of B cell responses.

A MicroRNA Network Controls Legionella pneumophila Replication in Human Macrophages via LGALS8 and MX1

Cases of Legionella pneumophila pneumonia occur worldwide, with potentially fatal outcome. When causing human disease, Legionella injects a plethora of virulence factors to reprogram macrophages to circumvent immune defense and create a replication niche. By analyzing Legionella-induced changes in miRNA expression and genomewide chromatin modifications in primary human macrophages, we identified a cell-autonomous immune network restricting Legionella growth. This network comprises three miRNAs governing expression of the cytosolic RNA receptor DDX58/RIG-I, the tumor suppressor TP53, the antibacterial effector LGALS8, and MX1, which has been described as an antiviral factor. Our findings for the first time link TP53, LGALS8, DDX58, and MX1 in one miRNA-regulated network and integrate them into a functional node in the defense against L. pneumophila.

Legionella pneumophila is an important cause of pneumonia. It invades alveolar macrophages and manipulates the immune response by interfering with signaling pathways and gene transcription to support its own replication. MicroRNAs (miRNAs) are critical posttranscriptional regulators of gene expression and are involved in defense against bacterial infections. Several pathogens have been shown to exploit the host miRNA machinery to their advantage. We therefore hypothesize that macrophage miRNAs exert positive or negative control over Legionella intracellular replication. We found significant regulation of 85 miRNAs in human macrophages upon L. pneumophila infection. Chromatin immunoprecipitation and sequencing revealed concordant changes of histone acetylation at the putative promoters. Interestingly, a trio of miRNAs (miR-125b, miR-221, and miR-579) was found to significantly affect intracellular L. pneumophila replication in a cooperative manner. Using proteome-analysis, we pinpointed this effect to a concerted downregulation of galectin-8 (LGALS8), DExD/H-box helicase 58 (DDX58), tumor protein P53 (TP53), and then MX dynamin-like GTPase 1 (MX1) by the three miRNAs. In summary, our results demonstrate a new miRNA-controlled immune network restricting Legionella replication in human macrophages.

Blood biomarkers differentiating viral versus bacterial pneumonia aetiology: a literature review

Background and objectives

The goal of this literature review is to compare current studies regarding the accuracy of different serum markers in differentiating viral from bacterial pneumonia in the pediatric population with what is employed in the medical settings at present. Currently there is still a lack of significant research, that would give us evaluation on biomarkers benefits towards getting a definite diagnosis of pneumonia. Finding out the potential of biomarkers to differentiate between viral and bacterial pneumonia is also important because knowing the exact pathogen would prevent irrational use of antibiotics. At present, irrational, broad-spectrum antibiotic use and increasing antibiotic resistance in microorganisms are still one of the greatest challenges in clinical settings. The use of biomarkers in clinical practice would not only facilitate accurate diagnosis, but would also help to reduce the amount of antibiotics overuse.

Materials and methods

Literature search conducted on Medline and Google Scholar using a combination of terms. Articles that were in English and within ten years of the search date were manually sorted according to inclusion and exclusion criteria. Results: Initial search returned n = 13,408. After activating filters, n = 140 were identified of which n = 12 included for literature review.

Conclusions

Rise or drop in the concentration of a single marker is not accurate enough for predicting viral/bacterial community acquired pneumonia. This is because there is overlapping to a varying extent depending on the marker cut-off values, detection methods, analyses, the desired specificity, and sensitivity. Furthermore, the presence of mixed infection makes almost all markers suboptimal to be used universally. New markers such as MxA1 and HMGB1 gave promising results. However, to replicate a similar testing condition in a clinical environment may not be practical. Another approach is to make use of more than one marker and combine with clinical signs and symptoms. This may not be cost-effective in many clinical settings; nevertheless, in many studies, marker combination greatly improved the predictive power.

Mx genes: host determinants controlling influenza virus infection and trans-species transmission

The human MxA protein, encoded by the interferon-inducible MX1 gene, is an intracellular influenza A virus (IAV) restriction factor. It can protect transgenic mice from severe IAV-induced disease, indicating a key role of human MxA for host survival and suggesting that natural variations in MX1 may account for inter-individual differences in disease severity among humans. MxA also provides a robust barrier against zoonotic transmissions of avian and swine IAV strains. Therefore, zoonotic IAV must acquire MxA escape mutations to achieve sustained human-to-human transmission. Here, we discuss recent progress in the field.

Long Noncoding RNA Lnc-MxA Inhibits Beta Interferon Transcription by Forming RNA-DNA Triplexes at Its Promoter

Previously, we identified a set of long noncoding RNAs (lncRNAs) that were differentially expressed in influenza A virus (IAV)-infected cells. In this study, we focused on lnc-MxA, which is upregulated during IAV infection. We found that the overexpression of lnc-MxA facilitates the replication of IAV, while the knockdown of lnc-MxA inhibits viral replication. Further studies demonstrated that lnc-MxA is an interferon-stimulated gene. However, lnc-MxA inhibits the Sendai virus (SeV)- and IAV-induced activation of beta interferon (IFN-β). A luciferase assay indicated that lnc-MxA inhibits the activation of the IFN-β reporter upon stimulation with RIG-I, MAVS, TBK1, or active IRF3 (IRF3-5D). These data indicated that lnc-MxA negatively regulates the RIG-I-mediated antiviral immune response. A chromatin immunoprecipitation (ChIP) assay showed that the enrichment of IRF3 and p65 at the IFN-β promoter in lnc-MxA-overexpressing cells was significantly lower than that in control cells, indicating that lnc-MxA interfered with the binding of IRF3 and p65 to the IFN-β promoter. Chromatin isolation by RNA purification (ChIRP), triplex pulldown, and biolayer interferometry assays indicated that lnc-MxA can bind to the IFN-β promoter. Furthermore, an electrophoretic mobility shift assay (EMSA) showed that lnc-MxA can form complexes with the IFN-β promoter fragment. These results demonstrated that lnc-MxA can form a triplex with the IFN-β promoter to interfere with the activation of IFN-β transcription. Using a vesicular stomatitis virus (VSV) infection assay, we confirmed that lnc-MxA can repress the RIG-I-like receptor (RLR)-mediated antiviral immune response and influence the antiviral status of cells. In conclusion, we revealed that lnc-MxA is an interferon-stimulated gene (ISG) that negatively regulates the transcription of IFN-β by forming an RNA-DNA triplex.IMPORTANCE IAV can be recognized as a nonself molecular pattern by host immune systems and can cause immune responses. However, the intense immune response induced by influenza virus, known as a "cytokine storm," can also cause widespread tissue damage (X. Z. J. Guo and P. G. Thomas, Semin Immunopathol 39:541-550, 2017, https://doi.org/10.1007/s00281-017-0636-y; S. Yokota, Nihon Rinsho 61:1953-1958, 2003; I. A. Clark, Immunol Cell Biol 85:271-273, 2007). Meanwhile, the detailed mechanisms involved in the balancing of immune responses in host cells are not well understood. Our studies reveal that, as an IFN-inducible gene, lnc-MxA functions as a negative regulator of the antiviral immune response. We uncovered the mechanism by which lnc-MxA inhibits the activation of IFN-β transcription. Our findings demonstrate that, as an ISG, lnc-MxA plays an important role in the negative-feedback loop involved in maintaining immune homeostasis.

Identification of distinctive interferon gene signatures in different types of myositis

OBJECTIVE

Activation of the type 1 interferon (IFN1) pathway is a prominent feature of dermatomyositis (DM) muscle and may play a role in the pathogenesis of this disease. However, the relevance of the IFN1 pathway in patients with other types of myositis such as the antisynthetase syndrome (AS), immune-mediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM) is largely unknown. Moreover, the activation of the type 2 interferon (IFN2) pathway has not been comprehensively explored in myositis. In this cross-sectional study, our objective was to determine whether IFN1 and IFN2 pathways are differentially activated in different types of myositis by performing RNA sequencing on muscle biopsy samples from 119 patients with DM, IMNM, AS, or IBM and on 20 normal muscle biopsies.

METHODS

The expression of IFN1- and IFN2-inducible genes was compared between the different groups.

RESULTS

The expression of IFN1-inducible genes was high in DM, moderate in AS, and low in IMNM and IBM. In contrast, the expression of IFN2-inducible genes was high in DM, IBM, and AS but low in IMNM. The expression of IFN-inducible genes correlated with the expression of genes associated with inflammation and muscle regeneration. Of note, ISG15 expression levels alone performed as well as composite scores relying on multiple genes to monitor activation of the IFN1 pathway in myositis muscle biopsies.

CONCLUSIONS

IFN1 and IFN2 pathways are differentially activated in different forms of myositis. This observation may have therapeutic implications because immunosuppressive medications may preferentially target each of these pathways.

MicroRNA-29b variants and MxA expression change during interferon beta therapy in patients with relapsing-remitting multiple sclerosis

BACKGROUND

Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system (CNS) characterized by immune-mediated demyelination and axonal injury. Myelin-reactive IFN-γ-producing Th1 cells has been shown to play an important role in the development of MS. MicroRNAs (miRNAs) are a new class of small non-coding RNA molecules about 22 nucleotides long which regulate gene expression post-transcriptionally by binding to 3' UTR of their mRNA targets, and resulting in degradation or transcriptional repression of the targeted mRNA. Accumulating evidence supports that miRNA dysregulation is linked to the pathogenesis of autoimmune diseases that include MS. miR-29b expression has been shown to be upregulated in memory CD4+T cells from relapsing-remitting MS (RR-MS) patients, which may reflect chronic Th1 inflammation. Interferon beta (IFN-β) benefits patients with MS and reduces symptoms of the RR-MS. MxA is induced by type I interferon and predicts IFN-β response in MS patients. The aim of this study was to evaluate miR-29b variants and MxA expression and serum IFN-γ level in responders and non-responders to IFN-β treatment.

METHODS

A total of 70 IFN-β treated RR-MS patients including 35 responders and 35 non-responders were enrolled. We analyzed the expression level of miR-29b variants and MxA using the peripheral blood of MS patients treated with IFN-β for more than one year. Real-time RT-PCR was performed to analyze miR-29b variants and MxA expression one year after initiation of IFN-β therapy. Serum cytokine level was measured by ELISA.

RESULTS

The results indicated that the expression level of miR-29b-3p changed related to IFN-β response. Moreover, miR-29b-5p was downregulated under IFN-β treatment in responders versus non-responders. MxA level was significantly decreased in the responders. There was no change in IFN-γ level following treatment with IFN-β in the MS patients.

CONCLUSIONS

Our results might provide fundamentals for the development of new markers of the biological effects of IFN-β therapy.

Mx1 in Hematopoietic Cells Protects against Thogoto Virus Infection

Myxovirus resistance 1 (Mx1) is an interferon-induced gene that encodes a GTPase that plays an important role in the defense of mammalian cells against influenza A and other viruses. The Mx1 protein can restrict a number of viruses independently of the expression of other interferon-induced genes. Mx genes are therefore considered to be an important part of the innate antiviral immune response. However, the possible impact of Mx expression in the hematopoietic cellular compartment has not been investigated in detail in the course of a viral infection. To address this, we performed bone marrow chimera experiments using congenic B6.A2G Mx1 ^+/+ and B6.A2G Mx1^-/- mice to study the effect of Mx1 expression in cells of hematopoietic versus nonhematopoietic origin. Mx1^+/+ mice were protected and Mx1^-/- mice were susceptible to influenza A virus challenge infection, regardless of the type of bone marrow cells (Mx1 ^+/+ or Mx1^-/- ) the animals had received. Infection with Thogoto virus, however, revealed that Mx1^-/- mice with a functional Mx1 gene in the bone marrow compartment showed reduced liver pathology compared with Mx1^-/- mice that had been grafted with Mx1 ^-/- bone marrow. The reduced pathology in these mice was associated with a reduction in Thogoto virus titers in the spleen, lung, and serum. Moreover, Mx1 ^+/+ mice with Mx1 ^-/- bone marrow failed to control Thogoto virus replication in the spleen. Mx1 in the hematopoietic cellular compartment thus contributes to protection against Thogoto virus infection.IMPORTANCE Mx proteins are evolutionarily conserved in vertebrates and can restrict a wide range of viruses in a cell-autonomous way. The contribution to antiviral defense of Mx1 expression in hematopoietic cells remains largely unknown. We show that protection against influenza virus infection requires Mx1 expression in the nonhematopoietic cellular compartment. In contrast, Mx1 in bone marrow-derived cells is sufficient to control disease and virus replication following infection with a Thogoto virus. This indicates that, in addition to its well-established antiviral activity in nonhematopoietic cells, Mx1 in hematopoietic cells can also play an important antiviral function. In addition, cells of hematopoietic origin that lack a functional Mx1 gene contribute to Thogoto virus dissemination and associated disease.