IL-28A and IL-29 mediate antiproliferative and antiviral signals in intestinal epithelial cells and murine CMV infection increases colonic IL-28A expression

New treatment alternatives for primary and metastatic colorectal cancer by an integrated transcriptome and network analyses

Metastatic colorectal cancer (CRC) is still in need of effective treatments. This study applies a holistic approach to propose new targets for treatment of primary and liver metastatic CRC and investigates their therapeutic potential in-vitro. An integrative analysis of primary and metastatic CRC samples was implemented for alternative target and treatment proposals. Integrated microarray samples were grouped based on a co-expression network analysis. Significant gene modules correlated with primary CRC and metastatic phenotypes were identified. Network clustering and pathway enrichments were applied to gene modules to prioritize potential targets, which were shortlisted by independent validation. Finally, drug-target interaction search led to three agents for primary and liver metastatic CRC phenotypes. Hesperadin and BAY-1217389 suppress colony formation over a 14-day period, with Hesperadin showing additional efficacy in reducing cell viability within 48 h. As both candidates target the G2/M phase proteins NEK2 or TTK, we confirmed their anti-proliferative properties by Ki-67 staining. Hesperadinin particular arrested the cell cycle at the G2/M phase. IL-29A treatment reduced migration and invasion capacities of TGF-β induced metastatic cell lines. In addition, this anti-metastatic treatment attenuated TGF-β dependent mesenchymal transition. Network analysis suggests IL-29A induces the JAK/STAT pathway in a preventive manner.

The potential of IFN-λ, IL-32γ, IL-6, and IL-22 as safeguards against human viruses: a systematic review and a meta-analysis

Many studies have investigated the antiviral activity of cytokines, including interleukin-6 (IL-6), interleukin-22 (IL-22), interleukin-32 gamma (IL-32γ), and interferon-lambda (IFN-λ) in diverse populations. This study aims to evaluate the role of these cytokines in inhibition of various human and animal viruses when administered exogenously. A comprehensive meta-analysis and systematic review were conducted on all the relevant studies from three databases. Standard mean differences (SMDs) of overall viral inhibition were used to generate the difference in the antiviral efficacy of these cytokines between control and experimental groups. A total of 4,618 abstracts for IL-6, 3,517 abstracts for IL-22, 2,160 abstracts for IL-32γ, and 1,026 abstracts for IFN-λ were identified, and 7, 4, 8, and 35 studies were included, respectively, for each cytokine. IFN-λ (SMD = 0.9540; 95% CI: 0.69-0.22) and IL-32γ (SMD = 0.459; 95% CI: 0.02-0.90) showed the highest influence followed by IL-6 (SMD = 0.456; CI: -0.04-0.95) and IL-22 (SMD = 0.244; 95% CI: -0.33-0.81). None of the cytokines represented heterogeneity (tau² > 0), but only IFN-λ indicated the funnel plot asymmetry (p = 0.0097). Results also indicated that IFN-λ and IL-32γ are more potent antivirals than IL-6 and IL-22. The collective findings of this study emphasize that exogenously administered pro-inflammatory cytokines, specifically IFN-λ and IL-32, exhibit a significant antiviral activity, thereby underscoring them as potent antiviral agents. Nonetheless, additional research is required to ascertain their clinical utility and potential for integration into combinatorial therapeutic regimens against viral infections.

Inhibition of human cytomegalovirus replication by interferon alpha can involve multiple anti-viral factors

The shortcomings of current direct-acting anti-viral therapy against human cytomegalovirus (HCMV) has led to interest in host-directed therapy. Here we re-examine the use of interferon proteins to inhibit HCMV replication utilizing both high and low passage strains of HCMV. Pre-treatment of cells with interferon alpha (IFNα) was required for robust and prolonged inhibition of both low and high passage HCMV strains, with no obvious toxicity, and was associated with an increased anti-viral state in HCMV-infected cells. Pre-treatment of cells with IFNα led to poor expression of HCMV immediate-early proteins from both high and low passage strains, which was associated with the presence of the anti-viral factor SUMO-PML. Inhibition of HCMV replication in the presence of IFNα involving ZAP proteins was HCMV strain-dependent, wherein a high passage HCMV strain was obviously restricted by ZAP and a low passage strain was not. This suggested that strain-specific combinations of anti-viral factors were involved in inhibition of HCMV replication in the presence of IFNα. Overall, this work further supports the development of strategies involving IFNα that may be useful to inhibit HCMV replication and highlights the complexity of the anti-viral response to HCMV in the presence of IFNα.

Deletion of Interferon Lambda Receptor Elucidates Susceptibility to the Murine Model of Biliary Atresia

Biliary atresia (BA) is a life-threatening cholangiopathy occurring in infancy, the most common indication for pediatric liver transplantation. The etiology of BA remains unknown; however, a viral etiology has been proposed as multiple viruses have been detected in explants of infants afflicted with BA. In the murine model of BA, Rhesus rotavirus (RRV) infection of newborn BALB/c pups results in a cholangiopathy that mirrors human BA. Infected BALB/c pups experience 100% symptomatology and mortality, while C57BL/6 mice are asymptomatic. Interferon-λ (IFN-λ) is an epithelial cytokine that provides protection against viral infection. We demonstrated that IFN-λ is highly expressed in C57BL/6, leading to reduced RRV replication. RRV-infection of C57BL/6 IFN-λ receptor knockout (C57BL/6 IFN-λR KO) pups resulted in 90% developing obstructive symptoms and 45% mortality with a higher viral titer in bile ducts and profound periportal inflammation compared to C57BL/6. Histology revealed complete biliary obstruction in symptomatic C57BL/6 IFN-λR KO pups, while C57BL/6 ducts were patent. These findings suggest that IFN-λ is critical in preventing RRV replication. Deficiency in IFN-λ permits RRV infection, which triggers the inflammatory cascade causing biliary obstruction. Further IFN-λ study is warranted as it may play an important role in infant susceptibility to BA.

Systematic levels of IL-29 and microRNA185-5p were not associated with severe COVID-19 in the Iranian population

BACKGROUND

Increased systematic pro-inflammatory cytokines is the main cause of the inflammatory conditions of the hospitalized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients. In this project, serum levels of IL-29 and whole blood levels of microRNA-185-5p (miR-185-5p) were evaluated in the hospitalized SARS-CoV-2 infected patients.

METHODS

This project was performed on the 60 hospitalized SARS-CoV-2 infected patients and 60 healthy controls to evaluate IL-29 and miR185-5p expression levels. IL-29 expression was explored using enzyme linked immunoassay (ELISA), while miR185-5p was evaluated using Real-Time PCR techniques.

RESULTS

The results demonstrated that neither IL-29 serum levels nor relative expressions of miR-185-5p were significantly different between patients and healthy controls.

CONCLUSION

Due to the results that are presented here, systematic levels of IL-29 and miR-185-5p cannot be considered as the main risk factors for induction of inflammation in the hospitalized SARS-CoV-2 infected patients.

PD-L1 and PD-L2 immune checkpoint protein induction by type III interferon in non-small cell lung cancer cells

INTRODUCTION

Despite the clinical success of PD-1/PD-1-ligand immunotherapy in non-small cell lung cancer (NSCLC), the appearance of primary and acquired therapy resistance is a major challenge reflecting that the mechanisms regulating the expression of the PD-1-ligands PD-L1 and PD-L2 are not fully explored. Type I and II interferons (IFNs) induce PD-L1 and PD-L2 expression. Here, we examined if PD-L1 and PD-L2 expression also can be induced by type III IFN, IFN-λ, which is peculiarly important for airway epithelial surfaces.

METHODS

In silico mRNA expression analysis of PD-L1 (CD274), PD-L2 (PDCD1LG2), and IFN- λ signaling signature genes in NSCLC tumors and cell lines was performed using RNA sequencing expression data from TCGA, OncoSG, and DepMap portals. IFN-λ-mediated induction of PD-L1 and PD-L2 expression in NSCLC cell lines was examined by real-time quantitative polymerase chain reaction and flow cytometry.

RESULTS

IFNL genes encoding IFN- λ variants are expressed in the majority of NSCLC tumors and cell lines along with the IFNLR1 and IL10R2 genes encoding the IFN-λ receptor subunits. The expression of PD-L1 and PD-L2 mRNA is higher in NSCLC tumors with IFNL mRNA expression compared to tumors without IFNL expression. In the NSCLC cell line HCC827, stimulation with IFN-λ induced both an increase in PD-L1 and PD-L2 mRNA expression and cell surface abundance of the corresponding proteins. In the NSCLC cell line A427, displaying a low basal expression of PD-L1 and PD-L2 mRNA and corresponding proteins, stimulation with IFN-λ resulted in an induction of the former.

CONCLUSION

The type III IFN, IFN- λ, is capable of inducing PD-L1 and PD-L2 expression, at least in some NSCLC cells, and this regulation will need acknowledgment in the development of new diagnostic procedures, such as gene expression signature profiles, to improve PD-1/PD-1-ligand immunotherapy in NSCLC.

Interleukin-29 Accelerates Vascular Calcification via JAK2/STAT3/BMP2 Signaling

Background Vascular calcification (VC), associated with enhanced cardiovascular morbidity and mortality, is characterized by the osteogenic transdifferentiation of vascular smooth muscle cells. Inflammation promotes VC initiation and progression. Interleukin (IL)-29, a newly discovered member of type III interferon, has recently been implicated in the pathogenesis of autoimmune diseases. Here we evaluated the role of IL-29 in the VC process and underlying inflammatory mechanisms. Methods and Results The mRNA expression of IL-29 was significantly increased and positively associated with an increase in BMP2 (bone morphogenetic protein 2) mRNA level in calcified carotid arteries from patients with coronary artery disease or chronic kidney disease. IL-29 and BMP2 proteins are colocalized in human calcified arteries. IL-29 binding to its specific receptor IL-28Rα (IL-28 receptor α) (IL-29/IL-28Rα) inhibited the proliferation of rat vascular smooth muscle cells without altering cell apoptosis or migration. IL-29 promoted the calcification of rat vascular smooth muscle cells and their osteogenic transdifferentiation in vitro as well as the rat aortic ring calcification ex vivo, induced by the calcification medium or osteogenic medium. The procalcification effect of IL-29 was reduced by pharmacological inhibition of IL-29/IL-28Rα binding as well as suppression of janus kinase 2/signal transducer and activator of transcription pathway activation, accompanied by decreased BMP2 expression in the cultured rat vascular smooth muscle cells. Conclusions These results suggest an important role of IL-29 in VC development, at least partly, via activating the janus kinase 2/signal transducer and activator of transcription 3 signaling. Inhibition of IL-29 or its specific receptor, IL-28Rα, may provide a novel strategy to reduce VC in patients with vascular diseases.

Signaling Lymphocytic Activation Molecule Family Member 1 Inhibits Porcine Reproductive and Respiratory Syndrome Virus Replication

The porcine reproductive and respiratory syndrome virus (PRRSV) causes a highly contagious disease in domestic swine. Signaling lymphocytic activation molecule family member 1 (SLAMF1) is a costimulatory factor that is involved in innate immunity, inflammation, and infection. Here, we demonstrate that overexpression of the SLAMF1 gene inhibited PRRSV replication significantly and reduced the levels of key signaling pathways, including MyD88, RIG-I, TLR2, TRIF, and inflammatory factors IL-6, IL-1β, IL-8, TNF-β, TNF-α, and IFN-α in vitro. However, the knockdown of the SLAMF1 gene could enhance replication of the PRRSV and the levels of key signaling pathways and inflammatory factors. Overall, our results identify a new, to our knowledge, antagonist of the PRRSV, as well as a novel antagonistic mechanism evolved by inhibiting innate immunity and inflammation, providing a new reference and direction for PRRSV disease resistance breeding.

A genetic screen identifies a protective type III interferon response to Cryptosporidium that requires TLR3 dependent recognition

Cryptosporidium is a leading cause of severe diarrhea and diarrheal-related death in children worldwide. As an obligate intracellular parasite, Cryptosporidium relies on intestinal epithelial cells to provide a niche for its growth and survival, but little is known about the contributions that the infected cell makes to this relationship. Here we conducted a genome wide CRISPR/Cas9 knockout screen to discover host genes that influence Cryptosporidium parvum infection and/or host cell survival. Gene enrichment analysis indicated that the host interferon response, glycosaminoglycan (GAG) and glycosylphosphatidylinositol (GPI) anchor biosynthesis are important determinants of susceptibility to C. parvum infection and impact on the viability of host cells in the context of parasite infection. Several of these pathways are linked to parasite attachment and invasion and C-type lectins on the surface of the parasite. Evaluation of transcript and protein induction of innate interferons revealed a pronounced type III interferon response to Cryptosporidium in human cells as well as in mice. Treatment of mice with IFNλ reduced infection burden and protected immunocompromised mice from severe outcomes including death, with effects that required STAT1 signaling in the enterocyte. Initiation of this type III interferon response was dependent on sustained intracellular growth and mediated by the pattern recognition receptor TLR3. We conclude that host cell intrinsic recognition of Cryptosporidium results in IFNλ production critical to early protection against this infection.

Critical role of interferons in gastrointestinal injury repair

The etiology of ulcerative colitis is poorly understood and is likely to involve perturbation of the complex interactions between the mucosal immune system and the commensal bacteria of the gut, with cytokines acting as important cross-regulators. Here we use IFN receptor-deficient mice in a dextran sulfate sodium (DSS) model of acute intestinal injury to study the contributions of type I and III interferons (IFN) to the initiation, progression and resolution of acute colitis. We find that mice lacking both types of IFN receptors exhibit enhanced barrier destruction, extensive loss of goblet cells and diminished proliferation of epithelial cells in the colon following DSS-induced damage. Impaired mucosal healing in double IFN receptor-deficient mice is driven by decreased amphiregulin expression, which IFN signaling can up-regulate in either the epithelial or hematopoietic compartment. Together, these data underscore the pleiotropic functions of IFNs and demonstrate that these critical antiviral cytokines also support epithelial regeneration following acute colonic injury.

Interleukin-28A induces epithelial barrier dysfunction in CD patient-derived intestinal organoids

Intestinal barrier dysfunction is a pathogenic hallmark in Crohn's disease (CD). Identifying key players that regulate intestinal barrier may provide novel leads for therapeutic intervention. Interleukin-28A (IL-28A) is a newly identified IL-10/interferon cytokine family member, with its most implicated function being antiviral and anti-proliferative properties. However, the role and underlying mechanisms of IL-28A in the regulation of epithelial barrier in CD remain so far unexplored. IL-28A levels were measured in the plasma and biopsies of CD patients and healthy subjects. CD patient-derived intestinal organoids were characterized by differentiation gene markers and then exposed to TNF-α, IFN-γ, IL-1β or LPS, or IL-28A with or without GLPG0634 (filgotinib). Epithelial permeability was assessed by FITC-D4 flux. Expression of junctional components was analyzed by qRT-PCR, immunofluorescence staining, or Western blotting. JAK-STAT activity was analyzed by Western blotting. IL-28A levels were significantly increased in the plasma and biopsies from active patients with CD as compared with healthy subjects. IL-28A and its receptor complex IL-28AR/IL-10R2 were detected in CD patient-derived intestinal organoids and showed a selective response to IFN-γ exposure. IL-28A triggered epithelial barrier disruption and accompanied by reduced ZO-1 and E-cadherin expression. This effect was mediated by JAK-STAT1 pathway. Pre-incubation with the JAK1 inhibitor filgotinib ameliorated the barrier dysfunction induced by IL-28A. These results identified IL-28A as a novel regulator of epithelial barrier function and could be a putative target for CD treatment. We provide novel basic evidence that restoring intestinal barrier is a potential mechanism that contributes to the clinical benefits of JAK1 inhibitor in patients with CD.NEW & NOTEWORTHY IL-28A levels were significantly increased in the plasma and biopsies from active patients with CD as compared with healthy subjects. IFN-γ exposure stimulated IL-28A expression in intestinal organoids. Partially mimicking the effect of IFN-γ, IL-28A impaired epithelial barrier function and disrupted junctional components through the activation of JAK-STAT1 signaling, whereas JAK1 inhibitor ameliorated the above-mentioned effects of IL-28A. These findings highlight the newly identified cytokine IL-28A as a novel contributor to CD pathogenesis and could be a putative target for CD treatment. We also provide new evidence for potential applications of JAK inhibition in CD therapy.

Association of TNFRSF1A and IFNLR1 Gene Polymorphisms with the Risk of Developing Breast Cancer and Clinical Pathologic Features

Several genes have been associated with breast cancer (BC) susceptibility. The tumor necrosis factor receptor superfamily, member 1A (TNFRSF1A), and interferon lambda receptor 1 (IFNLR1) genes encode receptors that mediate the action of inflammatory cytokines. Previous studies have demonstrated the association of the variants rs1800693 (TNFRSF1A) and rs4649203 (IFNLR1) with some inflammatory diseases. The present study aimed to verify a possible association of these variants with BC, its clinical pathologic features, as well as epidemiological data in a Brazilian population. A total of 243 patients and 294 individuals without history of BC were genotyped for these polymorphisms through TaqMan® SNP genotyping assays by qPCR. For the TNFRSF1A gene, no significant results were found. For IFNLR1, the AA genotype (p = 0.008) and the A allele (p = 0.02) were significantly associated with a lower risk of developing BC. When analyzing the age, it was observed that each increase of one year contributes to the development of BC (p < 0.001). Also, the smoking habit (p < 0.001) and body mass index (p = 0.018) increase the risk of disease development. Analyzing progesterone receptor factor an association was found with the AA genotype of the IFNLR1 (p = 0.02). The findings suggest that polymorphism in the immune-related IFNLR1 gene contribute to BC susceptibility in a Brazilian population. These findings can contribute to the further understanding of the role this gene and pathways in BC development.

Herpesviruses and the Type III Interferon System

Type III interferons (IFNs) represent the most recently discovered group of IFNs. Together with type I IFNs (e.g. IFN-α/β), type III IFNs (IFN-λ) are produced as part of the innate immune response to virus infection, and elicit an anti-viral state by inducing expression of interferon stimulated genes (ISGs). It was initially thought that type I IFNs and type III IFNs perform largely redundant functions. However, it has become evident that type III IFNs particularly play a major role in antiviral protection of mucosal epithelial barriers, thereby serving an important role in the first-line defense against virus infection and invasion at contact areas with the outside world, versus the generally more broad, potent and systemic antiviral effects of type I IFNs. Herpesviruseses are large DNA viruses, which enter their host via mucosal surfaces and establish lifelong, latent infections. Despite the importance of mucosal epithelial cells in the pathogenesis of herpesviruses, our current knowledge on the interaction of herpesviruses with type III IFN is limited and largely restricted to studies on the alphaherpesvirus herpes simplex virus (HSV). This review summarizes the current understanding about the role of IFN-λ in the immune response against herpesvirus infections.

Inhibition of Type III Interferon Expression in Intestinal Epithelial Cells-A Strategy Used by Coxsackie B Virus to Evade the Host's Innate Immune Response at the Primary Site of Infection?

Increasing evidence highlights the importance of the antiviral activities of the type III interferons (IFNλs; IL-28A, IL-28B, IL29, and IFNλ4) in the intestine. However, many viruses have developed strategies to counteract these defense mechanisms by preventing the production of IFNs. Here we use infection models, a clinical virus isolate, and several molecular biology techniques to demonstrate that both type I and III IFNs induce an antiviral state and attenuate Coxsackievirus group B (CVB) replication in human intestinal epithelial cells (IECs). While treatment of IECs with a viral mimic (poly (I:C)) induced a robust expression of both type I and III IFNs, no such up-regulation was observed after CVB infection. The blunted IFN response was paralleled by a reduction in the abundance of proteins involved in the induction of interferon gene transcription, including TIR-domain-containing adapter-inducing interferon-β (TRIF), mitochondrial antiviral-signaling protein (MAVS), and the global protein translation initiator eukaryotic translation initiation factor 4G (eIF4G). Taken together, this study highlights a potent anti-Coxsackieviral effect of both type I and III IFNs in cells located at the primary site of infection. Furthermore, we show for the first time that the production of type I and III IFNs in IECs is blocked by CVBs. These findings suggest that CVBs evade the host immune response in order to successfully infect the intestine.

Role of IFNLR1 gene in PRRSV infection of PAM cells

Background

Interferon lambda receptor 1 (IFNLR1) is a type II cytokine receptor that clings to interleukins IL-28A, IL29B, and IL-29 referred to as type III IFNs (IFN-λs). IFN-λs act through the JAK-STAT signaling pathway to exert antiviral effects related to preventing and curing an infection. Although the immune function of IFN-λs in virus invasion has been described, the molecular mechanism of IFNLR1 in that process is unclear.

Objectives

The purpose of this study was to elucidate the role of IFNLR1 in the pathogenesis and treatment of porcine reproductive and respiratory syndrome virus (PRRSV).

Methods

The effects of IFNLR1 on the proliferation of porcine alveolar macrophages (PAMs) during PRRSV infection were investigated using interference and overexpression methods.

Results

In this study, the expressions of the IFNLR1 gene in the liver, large intestine, small intestine, kidney, and lung tissues of Dapulian pigs were significantly higher than those in Landrace pigs. It was determined that porcine IFNLR1 overexpression suppresses PRRSV replication. The qRT-PCR results revealed that overexpression of IFNLR1 upregulated antiviral and IFN-stimulated genes. IFNLR1 overexpression inhibits the proliferation of PAMs and upregulation of p-STAT1. By contrast, knockdown of IFNLR1 expression promotes PAMs proliferation. The G0/G1 phase proportion in IFNLR1-overexpressing cells increased, and the opposite change was observed in IFNLR1-underexpressing cells. After inhibition of the JAK/STAT signaling pathway, the G2/M phase proportion in the IFNLR1-overexpressing cells showed a significant increasing trend. In conclusion, overexpression of IFNLR1 induces activation of the JAK/STAT pathway, thereby inhibiting the proliferation of PAMs infected with PRRSV.

Conclusion

Expression of the IFNLR1 gene has an important regulatory role in PRRSV-infected PAMs, indicating it has potential as a molecular target in developing a new strategy for the treatment of PRRSV.

Insight into the expression of RIG-I-like receptors in human third trimester placentas following ex vivo cytomegalovirus or vesicular stomatitis virus infection

A viral infection is detected through germline-encoded pattern-recognition receptors (PRRs) leading to the production of interferons (IFNs) and proinflammatory cytokines. The objective of this study was to investigate the expression of retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) in response to viral infection and the selected cytokine responses in the human term placenta. Placental villi and decidual explants were infected with human cytomegalovirus (CMV) or vesicular stomatitis virus (VSV) and cultured ex vivo to study viral infection. To evaluate DDX58 (RIG-I), IFIH1 (MDA5), and DHX58 (LGP2) expression, quantitative real-time PCR (qRT-PCR) was used. The expression of RLRs was detected by Western blotting. Cytokine and chemokine production, as well as RLR protein levels, were quantified using ELISA. The increased expression of both RIG-I and MDA5 and the enhanced secretion of IFN-ß were observed in response to VSV infection compared to mock-infected tissues. CMV infection resulted in higher transcript levels of DDX58 and IFIH1, while no changes in the cytokine production were observed. Our results indicate that RIG-I and MDA5 are specifically expressed in chorionic villi and deciduae in response to VSV infection. These findings suggest that RLRs may play a key role in pathogen recognition and the immune response against intrauterine viral transmission.

Lack of Association between IFNL3 Polymorphism and Human Papillomavirus Infection and Their Progression in HIV-Infected Women Receiving Antiretroviral Treatment

BACKGROUND

It has been reported that interferon-λ3 (IFNL3)might influence the pathogenesis and clearance of human papillomavirus (HPV) infection. The impact of IFNL3 single-nucleotide polymorphism (SNP) on HPV infection is currently unknown. The aim of this study was to investigate the association between variants in the IFNL3 region and HPV infection in women with human immunodeficiency virus (HIV) infection.

METHODS

A total of 236 HIV patients, including 65 HPV-negative and 171 HPV DNA-positive women, were enrolled into this study. The IFNL3 rs12979860 polymorphism was genotyped using a predesigned TaqMan SNP genotyping assay.

RESULTS

Data showed no significant differences in genotypes or allele frequencies between the HPV DNA-positive and the HPV-negative women (p > 0.05). After dividing the HPV-positive women according to cytology results into patients with abnormal and normal lesions, the genotype and allele distribution of the SNP did not significantly differ between the 2 groups (p > 0.05).

CONCLUSIONS

Our results showed that the IFNL3 rs12979860 polymorphism is not a major determinant of the susceptibility to HPV infection and their progression to abnormal cervical lesions in women living with HIV.

Interferon-Independent Innate Responses to Cytomegalovirus

The critical role of interferons (IFNs) in mediating the innate immune response to cytomegalovirus (CMV) infection is well established. However, in recent years the functional importance of the IFN-independent antiviral response has become clearer. IFN-independent, IFN regulatory factor 3 (IRF3)-dependent interferon-stimulated gene (ISG) regulation in the context of CMV infection was first documented 20 years ago. Since then several IFN-independent, IRF3-dependent ISGs have been characterized and found to be among the most influential in the innate response to CMV. These include virus inhibitory protein, endoplasmic reticulum-associated IFN-inducible (viperin), ISG15, members of the interferon inducible protein with tetratricopeptide repeats (IFIT) family, interferon-inducible transmembrane (IFITM) proteins and myxovirus resistance proteins A and B (MxA, MxB). IRF3-independent, IFN-independent activation of canonically IFN-dependent signaling pathways has also been documented, such as IFN-independent biphasic activation of signal transducer and activator of transcription 1 (STAT1) during infection of monocytes, differential roles of mitochondrial and peroxisomal mitochondrial antiviral-signaling protein (MAVS), and the ability of human CMV (HCMV) immediate early protein 1 (IE1) protein to reroute IL-6 signaling and activation of STAT1 and its associated ISGs. This review examines the role of identified IFN-independent ISGs in the antiviral response to CMV and describes pathways of IFN-independent innate immune response induction by CMV.

mRNA expression of IFN-λs in the gingival tissue of patients with chronic or aggressive periodontitis: A polymerase chain reaction study

BACKGROUND

Several studies have proven the existence of herpesviruses in periodontal pockets of patients with chronic or aggressive periodontitis. Recently discovered interferon lambda (IFN-λ) has antiviral properties and is induced by herpesviruses. The present study was a quantitative analysis of messenger RNA (mRNA) expression of IFN-λs (IFN-λ1, IFN-λ2, IFN-λ3) in the gingival tissues of patients with chronic or aggressive periodontitis.

METHODS

A total of 90 participants (50 men and 40 women; age range 19-50 years, mean age 31.50 ± 7.8) were categorized into three groups: healthy participants, patients with chronic periodontitis, and patients with aggressive periodontitis. mRNA expression of IFN-λs in gingival tissues was estimated using reverse transcriptase polymerase chain reaction and was correlated with clinical parameters such as gingival index (GI), probing pocket depth (PPD), and clinical attachment level (CAL).

RESULTS

mRNA of IFN-λ1, IFN-λ2, and IFN-λ3 was expressed in gingival tissues of healthy participants and in patients with chronic or aggressive periodontitis. The highest level of IFN-λ1 was observed in patients with aggressive periodontitis (3.049 ± 9.793), whereas IFN-λ2 (4.322 ± 11.310) and IFN-λ3 (11.932 ± 27.479) were highest in patients with chronic periodontitis. The difference in mRNA expression of IFN-λ1 (P = 0.008) and IFN-λ3 (P = 0.043) among three groups was statistically significant CONCLUSION: Increased quantity of IFN-λs in patients with chronic and patients with aggressive periodontitis suggests a role in periodontitis. Variation in the expression of IFN-λ1 and IFN-λ3 in patients with periodontitis needs to be further evaluated. The mRNA expression of antiviral IFN-λs in gingival tissues might enhance our understanding related to viral pathogenesis of periodontal diseases.

Genetic Polymorphisms within Interferon-λ Region and Interferon-λ3 in the Human Pathophysiology: Their Contribution to Outcome, Treatment, and Prevention of Infections with Hepatotropic Viruses

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Genetic polymorphisms within the interferon λ (IFN-λ) chromosomal region, mainly rs12979860 of IFN-λ4 gene (IFNL4), are known as associated with spontaneous hepatitis C virus (HCV) resolution and sustained viral response to therapy with pegylated interferon- α and ribavirin. Strong linkage disequilibrium of IFNL4 rs12979860 with IFNL4 rs368234815, which is casually associated with HCV spontaneous and therapeutical eradication, at least partially explains favorable HCV outcomes attributed to major homozygosity in rs12979860. Effects of IFN-based antiviral treatment are associated with pretreatment expression of the IFN-λ1 receptor, expression of hepatic IFN-stimulated genes, production of IFN- λ4, and preactivation of the JAK-STAT signaling. Nowadays direct-acting antivirals (DAAs) became a potent tool in the treatment of hepatitis C, but IFN-λs are still under investigation as potential antivirals and might be an option in HCV infection (DAA resistance, recurrent viremia, adverse effects).

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Patients with altered immunocompetence are especially prone to infections. In uremic subjects, polymorphisms within the IFN-λ chromosomal region associate with spontaneous HCV clearance, similarly like in the non-uremic population. Circulating IFN-λ3 shows a positive correlation with plasma titers of antibodies to surface antigen of hepatitis B virus (anti-HBs), which are crucial for protection against hepatitis B virus. More efficient anti-HBs production in the presence of higher IFN-λ3 levels might occur due to IFN-λ3-induced regulation of indoleamine 2,3-dioxygenase (IDO) expression. IFN-stimulated response element is a part of IDO gene promoter. It is worth further investigation whether IDO gene, circulating IDO, genetic polymorphisms within the IFN-λ region, and circulating IFN-λ3 act in concordance in immunological response to hepatotropic viruses.

Differential Regulation of Type I and Type III Interferon Signaling

Interferons (IFNs) are very powerful cytokines, which play a key role in combatting pathogen infections by controlling inflammation and immune response by directly inducing anti-pathogen molecular countermeasures. There are three classes of IFNs: type I, type II and type III. While type II IFN is specific for immune cells, type I and III IFNs are expressed by both immune and tissue specific cells. Unlike type I IFNs, type III IFNs have a unique tropism where their signaling and functions are mostly restricted to epithelial cells. As such, this class of IFN has recently emerged as a key player in mucosal immunity. Since the discovery of type III IFNs, the last 15 years of research in the IFN field has focused on understanding whether the induction, the signaling and the function of these powerful cytokines are regulated differently compared to type I IFN-mediated immune response. This review will cover the current state of the knowledge of the similarities and differences in the signaling pathways emanating from type I and type III IFN stimulation.

The generation and biological activity of a long-lasting recombinant human interferon-λ1

The previously generated recombinant human (rh) interferon (IFN)-λ1 protein has a short half-life, and this feature makes it challenging to conduct studies on potential clinical applications for rhIFN-λ1. In an attempt to overcome this difficulty, we constructed a 'long-life' version of rhIFN-λ1. This modified rhIFN-λ1, named rhIFN-λ1-CTPON, has a human chorionic gonadotropin β subunit carboxyl-terminal peptide (CTP) and an N-glycosylation sequence linked to its C-terminus. We confirmed the sequence of rhIFN-λ1-CTPON by mass spectrometry and then measured its biological activities. The results show that rhIFN-λ1-CTPON had antiviral activity and anti-proliferation activity in vitro that were similar to those of rhIFN-λ1 and that it similarly promoted natural killer cell cytotoxicity. Notably, the in vivo half-life of rhIFN-λ1-CTPON was determined to be 3-fold higher than that of rhIFN-λ1. We also assessed the anti-hepatitis B virus activity of rhIFN-λ1-CTPON; it was able to inhibit the production of the antigens HBs-Ag and HBe-Ag and induce antiviral gene expression. In conclusion, rhIFN-λ1-CTPON has a longer half-life than rhIFN-λ1 and has similar biological activities, so rhIFN-λ1-CTPON is an appropriate substitute for rhIFN-λ1 in the further study of potential clinical applications for rhIFN- λ1.

IL28RA inhibits human epidermal keratinocyte proliferation by inhibiting cell cycle progression

Interleukin (IL) 28 receptor α (IL28RA) is a well-known candidate for psoriasis susceptibility based on previous genome-wide association study (GWAS) analysis. However, the function of IL28RA in psoriasis has not been elucidated. In the present study, the expression of IL28RA was significantly decreased in lesional tissues from patients with plaque psoriasis when compared with the expression observed in adjacent non-lesional tissues. In vitro studies further demonstrated that in the presence of IL-29, HaCaT keratinocytes with IL28RA knockdown exhibited a faster rate of proliferation than control cells, and an enhanced ratio of cells in the S and G2/M phase. By contrast, IL28RA overexpression inhibited the proliferation of HaCaT keratinocytes and caused cell cycle arrest at the G0/G1 phases. Western blot analysis revealed that knockdown of IL28RA upregulated cyclinB1 expression and downregulated cyclinE expression; the opposite results were observed in the IL28RA-overexpressing HaCaT cells. Finally, a mechanistic study revealed that IL28RA functions through the activation of the Janus kinase-signal transducer and activator of transcription signaling pathway to exert its anti-proliferative effect. These results suggested that weak expression of IL28RA may contribute to the pathogenesis of psoriasis and that IL28RA may be an effective drug target for the treatment of psoriasis. However, further in vivo studies are required.

Targeting IL-10 Family Cytokines for the Treatment of Human Diseases

Members of the interleukin (IL)-10 family of cytokines play important roles in regulating immune responses during host defense but also in autoimmune disorders, inflammatory diseases, and cancer. Although IL-10 itself primarily acts on leukocytes and has potent immunosuppressive functions, other family members preferentially target nonimmune compartments, such as tissue epithelial cells, where they elicit innate defense mechanisms to control viral, bacterial, and fungal infections, protect tissue integrity, and promote tissue repair and regeneration. As cytokines are prime drug targets, IL-10 family cytokines provide great opportunities for the treatment of autoimmune diseases, tissue damage, and cancer. Yet no therapy in this space has been approved to date. Here, we summarize the diverse biology of the IL-10 family as it relates to human disease and review past and current strategies and challenges to target IL-10 family cytokines for clinical use.

Interleukin 28A.rs12980602 and interleukin 28B.rs8103142 genotypes could be protective against HCV infection among Egyptians

Previous studies showed that interleukin (IL)-28B gene polymorphisms were associated with hepatitis C Virus (HCV) infection and treatment outcomes. We tested whether single-nucleotide polymorphisms (SNPs) in IL-28A and IL-28B are associated with HCV infection among Egyptians with HCV genotype 4 infections. We enrolled 144 chronic HCV patients, 72 spontaneously resolved HCV subjects, and 69 healthy controls. Four SNPs in IL-28A and IL-28B genes (IL-28A.rs12980602, IL-28B.rs12979860, IL-28B.rs8099917, and IL-28B.rs8103142) were genotyped. The most frequent IL-28B haplotype "TCT" was significantly more frequent in HCV-infected subjects than in HCV negative subjects (62.2% vs. 48.6%, respectively; p = 0.005). The frequency of IL-28A.rs12980602 "T" allele was significantly higher than the "C" allele in healthy controls compared to HCV-infected subjects (p < 0.001) with the "TT" genotype significantly higher in healthy controls compared to HCV-infected subjects (p < 0.001) with no association with viral load (p = 0.11) among chronically infected subjects. The results, also, confirmed the previous role of IL-28B SNPs in predicting HCV infection outcome. Importantly, IL-28B.rs8099917 "TT" genotype was significantly associated with low viral load in HCV-infected subjects, while the remaining three SNPs did not. The three IL-28B SNPs were in linkage disequilibrium (D' > 0.68; r2 > 0.43) for all comparisons in HCV patients, while there was no linkage disequilibrium of IL-28A polymorphisms and the three IL-28B SNPs. In conclusion, IL-28A.rs12980602 and IL-28B.rs8103142 TT genotype could be protective against HCV infection. Also, IL-28B.rs12979860, IL-28B.rs8099917, and IL-28B.rs8103142 SNPs predicted the outcome of HCV infection among genotype-4-infected Egyptians. Moreover, IL-28B.rs8099917 SNP affected the viral load in chronic HCV patients.

IL28B, IL29 and micro-RNA 548 in subacute sclerosing panencephalitis as a rare disease

Subacute sclerosing panencephalitis (SSPE) is a progressive neurodegenerative disease which affects children and young adults, caused by a persistent infection of defective measles virus. IFN-λs (IL-28A, IL-28B and IL-29) are a group of cytokines mediating antiviral responses. It has been shown that IL-29 levels are significantly higher in infected cells with defective measles virus. IL-29 expression is thought to be regulated at post-transcriptional level and miRNA-548 family targets the 3'UTR of the IFNL1 gene. Impaired immune system has an important role as well as viral factors in SSPE. The aim of our study investigates whether IL-28B, IL-29 levels and gene polymorphisms contribute to the damaged immune response leading to the development of SSPE. Also possible association of miR-548 family with IL-29 and SSPE is explored. Frequencies of rs12979860, rs8099917, rs30461, serum levels of IL-28B, IL-29 and expression levels of miR-548b, miR-548c, miR-548i are determined at 64 SSPE patients and 68 healthy controls. Serum IL-29 levels are statistically significant higher in SSPE patients. Allele frequencies of rs8099917 are statistically significant higher in SSPE patients and resulted G allele is found to increase 2.183-fold risk of SSPE. The expression levels of miR-548b-5p, miR-548c-5p and miR-548i are found to be statistically significant higher in SSPE patients. Dramatically increased level of IL-29 seen in patient group indicates that the elevated miR-548 expression is compensatory result of the over-activated immune system response. Further studies referred to IL28, IL29 and related miRNA's will be enlightened the pathogenesis of SSPE.

Interferon lambda 3/4 polymorphisms are associated with AIDS-related Kaposi's sarcoma

BACKGROUND

Kaposi's sarcoma, the most common AIDS-related cancer, represents a major public concern in resource-limited countries. Single nucleotide polymorphisms within the Interferon lambda 3/4 region (IFNL3/4) determine the expression, function of IFNL4, and influence the clinical course of an increasing number of viral infections.

OBJECTIVES

To analyze whether IFNL3/4 variants are associated with susceptibility to AIDS-related Kaposi's sarcoma among MSM enrolled in the Swiss HIV Cohort Study (SHCS).

METHODS

The risk of developing Kaposi's sarcoma according to the carriage of IFNL3/4 SNPs rs8099917 and rs12980275 and their haplotypic combinations was assessed by using cumulative incidence curves and Cox regression models, accounting for relevant covariables.

RESULTS

Kaposi's sarcoma was diagnosed in 221 of 2558 MSM Caucasian SHCS participants. Both rs12980275 and rs8099917 were associated with an increased risk of Kaposi's sarcoma (cumulative incidence 15 versus 10%, P = 0.01 and 16 versus 10%, P = 0.009, respectively). Diplotypes predicted to produce the active P70 form (cumulative incidence 16 versus 10%, P = 0.01) but not the less active S70 (cumulative incidence 11 versus 10%, P = 0.7) form of IFNL4 were associated with an increased risk of Kaposi's sarcoma, compared with those predicted not to produce IFNL4. The associations remained significant in a multivariate Cox regression model after adjustment for age at infection, combination antiretroviral therapy, median CD4+ T-cell count nadir and CD4+ slopes (hazard ratio 1.42, 95% confidence interval 1.06-1.89, P = 0.02 for IFLN P70 versus no IFNL4).

CONCLUSION

This study reports for the first time an association between IFNL3/4 polymorphisms and susceptibility to AIDS-related Kaposi's sarcoma.

Differential induction of interferon stimulated genes between type I and type III interferons is independent of interferon receptor abundance

It is currently believed that type I and III interferons (IFNs) have redundant functions. However, the preferential distribution of type III IFN receptor on epithelial cells suggests functional differences at epithelial surfaces. Here, using human intestinal epithelial cells we could show that although both type I and type III IFNs confer an antiviral state to the cells, they do so with distinct kinetics. Type I IFN signaling is characterized by an acute strong induction of interferon stimulated genes (ISGs) and confers fast antiviral protection. On the contrary, the slow acting type III IFN mediated antiviral protection is characterized by a weaker induction of ISGs in a delayed manner compared to type I IFN. Moreover, while transcript profiling revealed that both IFNs induced a similar set of ISGs, their temporal expression strictly depended on the IFNs, thereby leading to unique antiviral environments. Using a combination of data-driven mathematical modeling and experimental validation, we addressed the molecular reason for this differential kinetic of ISG expression. We could demonstrate that these kinetic differences are intrinsic to each signaling pathway and not due to different expression levels of the corresponding IFN receptors. We report that type III IFN is specifically tailored to act in specific cell types not only due to the restriction of its receptor but also by providing target cells with a distinct antiviral environment compared to type I IFN. We propose that this specific environment is key at surfaces that are often challenged with the extracellular environment.

Distinct Effects of Type I and III Interferons on Enteric Viruses

Interferons (IFNs) are key host cytokines in the innate immune response to viral infection, and recent work has identified unique roles for IFN subtypes in regulating different aspects of infection. Currently emerging is a common theme that type III IFNs are critical in localized control of infection at mucosal barrier sites, while type I IFNs are important for broad systemic control of infections. The intestine is a particular site of interest for exploring these effects, as in addition to being the port of entry for a multitude of pathogens, it is a complex tissue with a variety of cell types as well as the presence of the intestinal microbiota. Here we focus on the roles of type I and III IFNs in control of enteric viruses, discussing what is known about signaling downstream from these cytokines, including induction of specific IFN-stimulated genes. We review viral strategies to evade IFN responses, effects of IFNs on the intestine, interactions between IFNs and the microbiota, and briefly discuss the role of IFNs in controlling viral infections at other barrier sites. Enhanced understanding of the coordinate roles of IFNs in control of viral infections may facilitate development of antiviral therapeutic strategies; here we highlight potential avenues for future exploration.

Infection with Classical Swine Fever Virus Induces Expression of Type III Interferons and Activates Innate Immune Signaling

Classical swine fever virus (CSFV) commonly infects the lymphatic tissues and immune cells of pigs and could cause a lethal disease in the animals. The process and release of cytokines like type III interferons (IFNs) is one of the important responses of the host innate immunity to viral infection. However, little information is available about type III IFN response to the CSFV infection. In this study, we investigated the expression of type III IFNs including interleukin-28B (IL-28B) and IL-29 in PK-15 cells and pigs following CSFV infection. We found that infection with CSFV was able to induce expression of IL-28B and IL-29 in PK-15 cells, although the increased levels of type III IFNs were limited. Importantly, up-regulation of IL-28B and IL-29 was further observed in CSFV infected animal tissues. The production of IL-28B and IL-29 was reduced by the inactivation of NF-κB in cells, indicating that activated NF-κB is required for efficient expression of type III IFNs induced by CSFV. Moreover, our experiments demonstrated that infection with CSFV strongly stimulated the downstream of STAT1 signaling in vitro and in vivo. In addition, several critical IFN-stimulated genes (ISGs) including IFITM3, OASL, OAS1, and ISG15 were significantly upregulated at both mRNA and protein levels in PK-15 cells and infected pigs. Together, these results reveal that CSFV can trigger host antiviral immune responses including production of type III IFNs, activation of STAT1, and induction of some critical ISGs.

Identification of a Predominantly Interferon-λ-Induced Transcriptional Profile in Murine Intestinal Epithelial Cells

Type I (α and β) and type III (λ) interferons (IFNs) induce the expression of a large set of antiviral effector molecules via their respective surface membrane receptors. Whereas most cell types respond to type I IFN, type III IFN preferentially acts on epithelial cells and protects mucosal organs such as the lung and gastrointestinal tract. Despite the engagement of different receptor molecules, the type I and type III IFN-induced signaling cascade and upregulated gene profile is thought to be largely identical. Here, we comparatively analyzed the response of gut epithelial cells to IFN-β and IFN-λ2 and identified a set of genes predominantly induced by IFN-λ2. We confirm the influence of epithelial cell polarization for enhanced type III receptor expression and demonstrate the induction of predominantly IFN-λ2-induced genes in the gut epithelium in vivo. Our results suggest that IFN-λ2 targets the epithelium and induces genes to adjust the antiviral host response to the requirements at mucosal body sites.

IL-29 Enhances CXCL10 Production in TNF-α-stimulated Human Oral Epithelial Cells

Interleukin-29 (IL-29) is a cytokine belonging to the Type III interferon family. It was recently detected in the gingival crevicular fluid of periodontitis patients. However, the role of IL-29 in the pathogenesis of periodontal disease remains unknown. The aim of this study was to examine the effects of IL-29 on C-X-C motif chemokine ligand 10 (CXCL10) production in human oral epithelial cells. We measured CXCL10 production in TR146 cells, which is a human oral epithelial cell line, using an enzyme-linked immunosorbent assay. We used a Western blot analysis to detect IL-29 receptor expression and the phosphorylation levels of signal transduction molecules, including p38 mitogen-activated protein kinases (MAPK), signal transducer and activator of transcription 3 (STAT3), and nuclear factor (NF)- κB p65, in the TR146 cells. The TR146 cells expressed the IL-29 receptor. IL-29 induced CXCL10 production in the TR146 cells. IL-29 significantly enhanced CXCL10 production in tumor necrosis factor (TNF)-α-stimulated TR146 cells. The p38 MAPK, STAT3, and NF-κB pathways were found to be related to the IL-29-induced enhancement of CXCL10 production in TNF-α-stimulated TR146 cells. IL-29 promotes T helper 1-cell accumulation in periodontal lesions by inducing CXCL10 production in oral epithelial cells.

Cross-species antiviral activity of goose interferon lambda against duck plague virus is related to its positive self-regulatory feedback loop

Duck plague virus (DPV) is a virus of the Herpesviridae family that leads to acute disease with a high mortality rate in ducks. Control of the disease contributes to the development of poultry breeding. Type III IFN family (IFN-λs) is a novel member of the IFN family, and goose IFN-λ (goIFN-λ) is a newly identified gene whose antiviral function has only been investigated to a limited extent. Here, the cross-species antiviral activity of goIFN-λ against DPV in duck embryo fibroblasts (DEFs) was studied. We found that pre-treatment with goIFN-λ greatly increased the expression of IFN-λ in both heterologous DEFs and homologous goose embryo fibroblasts (GEFs), while differentially inducing IFNα- and IFN-stimulated genes. Additionally, a positive self-regulatory feedback loop of goIFN-λ was blocked by a mouse anti-goIFN-λ polyclonal antibody, which was confirmed in both homologous GEFs and goose peripheral blood mononuclear cells (PBMCs). The suppression of the BAC-DPV-EGFP by goIFN-λ in DEFs was confirmed by fluorescence microscopy, flow cytometry (FCM) analysis, viral copies and titre detection, which can be rescued by mouse anti-goIFN-λ polyclonal antibody incubation. Finally, reporter gene assays indicated that the cross-species antiviral activity of goIFN-λ against BAC-DPV-EGFP is related to its positive self-regulatory feedback loop and subsequent ISG induction. Our data shed light on the fundamental mechanisms of goIFN-λ antiviral function in vitro and extend the considerable range of therapeutic applications in multiple-poultry disease.

Activation of Epithelial Signal Transducer and Activator of Transcription 1 by Interleukin 28 Controls Mucosal Healing in Mice With Colitis and Is Increased in Mucosa of Patients With Inflammatory Bowel Disease

BACKGROUND & AIMS

We investigated the roles of interleukin 28A (also called IL28A or interferon λ2) in intestinal epithelial cell (IEC) activation, studying its effects in mouse models of inflammatory bowel diseases (IBD) and intestinal mucosal healing.

METHODS

Colitis was induced in C57BL/6JCrl mice (controls), mice with IEC-specific disruption of Stat1 (Stat1IEC-KO), mice with disruption of the interferon λ receptor 1 gene (Il28ra-/-), and mice with disruption of the interferon regulatory factor 3 gene (Irf3-/-), with or without disruption of Irf7 (Irf7-/-). We used high-resolution mini-endoscopy and in vivo imaging methods to assess colitis progression. We used 3-dimensional small intestine and colon organoids, along with RNA-Seq and gene ontology methods, to characterize the effects of IL28 on primary IECs. We studied the effects of IL28 on the human intestinal cancer cell line Caco-2 in a wound-healing assay, and in mice colon wounds. Colonic biopsies and resected tissue from patients with IBD (n = 62) and patients without colon inflammation (controls, n = 23) were analyzed by quantitative polymerase chain rection to measure expression of IL28A, IL28RA, and other related cytokines; biopsy samples were also analyzed by immunofluorescence to identify sources of IL28 production. IECs were isolated from patient tissues and incubated with IL28; signal transducer and activator of transcription 1 (STAT1) phosphorylation was measured by immunoblots and confocal imaging.

RESULTS

Lamina propria cells in colon tissues of patients with IBD, and mice with colitis, had increased expression of IL28 compared with controls; levels of IL28R were increased in the colonic epithelium of patients with IBD and mice with colitis. Administration of IL28 induced phosphorylation of STAT1 in primary human and mouse IECs, increasing with dose. Il28ra-/-, Irf3-/-, Irf3-/-Irf7-/-, as well as Stat1IEC-KO mice, developed more severe colitis after administration of dextran sulfate sodium than control mice, with reduced epithelial restitution. Il28ra-/- and Stat1IEC-KO mice also developed more severe colitis in response to oxazolone than control mice. We found IL28 to induce phosphorylation (activation) of STAT1 in epithelial cells, leading to their proliferation in organoid culture. Administration of IL28 to mice with induced colonic wounds promoted mucosal healing.

CONCLUSIONS

IL28 controls proliferation of IECs in mice with colitis and accelerates mucosal healing by activating STAT1. IL28 might be developed as a therapeutic agent for patients with IBD.

STING Is Involved in Antiviral Immune Response against VZV Infection via the Induction of Type I and III IFN Pathways

Varicella zoster virus (VZV) is a human-restricted α-herpesvirus that exhibits tropism for the skin. The VZV host receptors and downstream signaling pathways responsible for the antiviral innate immune response in the skin are not completely understood. Here, we show that STING mediates an important host defense against VZV infection in dermal cells including human dermal fibroblasts and HaCaT keratinocytes. Inhibition of STING using small interfering-RNA or short hairpin RNA-mediated gene disruption resulted in enhanced viral replication but diminished IRF3 phosphorylation and induction of IFNs and proinflammatory cytokines. Pretreatment with STING agonists resulted in reduced VZV glycoprotein E expression and viral replication. Additionally, using RNA sequencing to analyze dual host and VZV transcriptomes, we identified several host immune genes significantly induced by VZV infection. Furthermore, significant up-regulation of IFN-λ secretion was observed after VZV infection, partly through a STING-dependent pathway; IFN-λ was shown to be crucial for antiviral defense against VZV in human dermal cells. In conclusion, our data provide an important insight into STING-mediated induction of type I and III IFNs and subsequent antiviral signaling pathways that regulate VZV replication in human dermal cells.

Type I and Type III Interferons Display Different Dependency on Mitogen-Activated Protein Kinases to Mount an Antiviral State in the Human Gut

Intestinal epithelial cells (IECs) are constantly exposed to commensal flora and pathogen challenges. How IECs regulate their innate immune response to maintain gut homeostasis remains unclear. Interferons (IFNs) are cytokines produced during infections. While type I IFN receptors are ubiquitously expressed, type III IFN receptors are expressed only on epithelial cells. This epithelium specificity strongly suggests exclusive functions at epithelial surfaces, but the relative roles of type I and III IFNs in the establishment of an antiviral innate immune response in human IECs are not clearly defined. Here, we used mini-gut organoids to define the functions of types I and III IFNs to protect the human gut against viral infection. We show that primary non-transformed human IECs, upon viral challenge, upregulate the expression of both type I and type III IFNs at the transcriptional level but only secrete type III IFN in the supernatant. However, human IECs respond to both type I and type III IFNs by producing IFN-stimulated genes that in turn induce an antiviral state. Using genetic ablation of either type I or type III IFN receptors, we show that either IFN can independently restrict virus infection in human IECs. Importantly, we report, for the first time, differences in the mechanisms by which each IFN establishes the antiviral state. Contrary to type I IFN, the antiviral activity induced by type III IFN is strongly dependent on the mitogen-activated protein kinases signaling pathway, suggesting a pathway used by type III IFNs that non-redundantly contributes to the antiviral state. In conclusion, we demonstrate that human intestinal epithelial cells specifically regulate their innate immune response favoring type III IFN-mediated signaling, which allows for efficient protection against pathogens without producing excessive inflammation. Our results strongly suggest that type III IFN constitutes the frontline of antiviral response in the human gut. We propose that mucosal surfaces, particularly the gastrointestinal tract, have evolved to favor type III IFN-mediated response to pathogen infections as it allows for spatial segregation of signaling and moderate production of inflammatory signals which we propose are key to maintain gut homeostasis.

Type I and III Interferon in the Gut: Tight Balance between Host Protection and Immunopathology

The intestinal mucosa forms an active interface to the outside word, facilitating nutrient and water uptake and at the same time acts as a barrier toward the highly colonized intestinal lumen. A tight balance of the mucosal immune system is essential to tolerate harmless antigens derived from food or commensals and to effectively defend against potentially dangerous pathogens. Interferons (IFN) provide a first line of host defense when cells detect an invading organism. Whereas type I IFN were discovered almost 60 years ago, type III IFN were only identified in the early 2000s. It was initially thought that type I IFN and type III IFN performed largely redundant functions. However, it is becoming increasingly clear that type III IFN exert distinct and non-redundant functions compared to type I IFN, especially in mucosal tissues. Here, we review recent progress made in unraveling the role of type I/III IFN in intestinal mucosal tissue in the steady state, in response to mucosal pathogens and during inflammation.

IFN-λ Inhibits Drug-Resistant HIV Infection of Macrophages

Type III interferons (IFN-λs) have been demonstrated to inhibit a number of viruses, including HIV. Here, we further examined the anti-HIV effect of IFN-λs in macrophages. We found that IFN-λs synergistically enhanced anti-HIV activity of antiretrovirals [azidothymidine (AZT), efavirenz, indinavir, and enfuvirtide] in infected macrophages. Importantly, IFN-λs could suppress HIV infection of macrophages with the drug-resistant strains, including AZT-resistant virus (A012) and reverse transcriptase inhibitor-resistant virus (TC49). Mechanistically, IFN-λs were able to induce the expression of several important anti-HIV cellular factors, including myxovirus resistance 2 (Mx2), a newly identified HIV post-entry inhibitor and tetherin, a restriction factor that blocks HIV release from infected cells. These observations provide additional evidence to support the potential use of IFN-λs as therapeutics agents for the treatment of HIV infection.

Interferon Lambda: Modulating Immunity in Infectious Diseases

Interferon lambdas (IFN-λs; IFNL1-4) modulate immunity in the context of infections and autoimmune diseases, through a network of induced genes. IFN-λs act by binding to the heterodimeric IFN-λ receptor (IFNLR), activating a STAT phosphorylation-dependent signaling cascade. Thereby hundreds of IFN-stimulated genes are induced, which modulate various immune functions via complex forward and feedback loops. When compared to the well-characterized IFN-α signaling cascade, three important differences have been discovered. First, the IFNLR is not ubiquitously expressed: in particular, immune cells show significant variation in the expression levels of and susceptibilities to IFN-λs. Second, the binding affinities of individual IFN-λs to the IFNLR varies greatly and are generally lower compared to the binding affinities of IFN-α to its receptor. Finally, genetic variation in the form of a series of single-nucleotide polymorphisms (SNPs) linked to genes involved in the IFN-λ signaling cascade has been described and associated with the clinical course and treatment outcomes of hepatitis B and C virus infection. The clinical impact of IFN-λ signaling and the SNP variations may, however, reach far beyond viral hepatitis. Recent publications show important roles for IFN-λs in a broad range of viral infections such as human T-cell leukemia type-1 virus, rotaviruses, and influenza virus. IFN-λ also potentially modulates the course of bacterial colonization and infections as shown for Staphylococcus aureus and Mycobacterium tuberculosis. Although the immunological processes involved in controlling viral and bacterial infections are distinct, IFN-λs may interfere at various levels: as an innate immune cytokine with direct antiviral effects; or as a modulator of IFN-α-induced signaling via the suppressor of cytokine signaling 1 and the ubiquitin-specific peptidase 18 inhibitory feedback loops. In addition, the modulation of adaptive immune functions via macrophage and dendritic cell polarization, and subsequent priming, activation, and proliferation of pathogen-specific T- and B-cells may also be important elements associated with infectious disease outcomes. This review summarizes the emerging details of the IFN-λ immunobiology in the context of the host immune response and viral and bacterial infections.

Short communication: antiviral activity of porcine IFN-λ3 against porcine epidemic diarrhea virus in vitro

A new family of IFNs called type III IFN or IFN-λ has been described, and shown to induce antiviral activity against several viruses in the cell culture. In this study, the molecular cloning, expression, and antiporcine epidemic diarrhea virus (PEDV) activity of porcine IFN-λ3 (poIFN-λ3) were reported. The full-length poIFN-λ3 cDNA sequence encoded 196 amino acids with a 23 amino acid signal peptide. Sequence alignments showed that poIFN-λ3 had an amino acid sequence similarity to Ovis aries (78.1 %), Bos taurus (76.0 %), Tupaia belangeri (71.3 %), Equus caballus (69.9 %), and Homo sapiens (69.9 %). The phylogenetic analysis based on the genomic sequences indicated that poIFN-λ3 is located in the same branch as B. taurus and O. aries IFN-λ3. The poIFN-λ3 without a signal anchor sequence was efficiently expressed in Escherichia coli, and the purified recombinant poIFN-λ3 exhibited significant antiviral effects against PEDV in a dose- and time-dependent manner. This inhibitory effect of poIFN-λ3 on PEDV was observed under three different treatment conditions. The highest inhibition of PEDV was observed in Vero E6 cell cultures pretreated with poIFN-λ3 (prior to PEDV infection). In addition, poIFN-λ3 was able to induce the expression of IFN-stimulated genes, including ISG15, OAS1, and Mx1 in Vero E6 cells. These data demonstrate that poIFN-λ3 has antiviral activity against PEDV and may serve as a useful biotherapeutic candidate to inhibit PEDV or other viruses in swine.

Targeting IFN-λ: therapeutic implications

INTRODUCTION

Type-III interferons (IFN-λ), the most recently discovered family of IFNs, shares common features with other family members, but also has many distinctive activities. IFN-λ uniquely has a different receptor complex, and a more focused pattern of tissue expression and signaling effects, from other classes of IFNs. Multiple genome-wide association studies (GWAS) and subsequent validation reports suggest a pivotal role for polymorphisms near the IFNL3 gene in hepatitis C clearance and control, as also for several other epithelial cell tropic viruses. Apart from its antiviral activity, IFN-λ possesses anti-tumor, immune-inflammatory and homeostatic functions. The overlapping effects of IFN-λ with type I IFN, with a restricted tissue expression pattern renders IFN-λ an attractive therapeutic target for viral infection, cancer and autoimmune diseases, with limited side effects. Areas covered: This review will summarize the current and future therapeutic opportunities offered by this most recently discovered family of interferons. Expert opinion: Our knowledge on IFN-λ is rapidly expanding. Though there are many remaining questions and challenges that require elucidation, the unique characteristics of IFN-λ increases enthusiasm that multiple therapeutic options will emerge.

Crystal Structure of a Complex of the Intracellular Domain of Interferon λ Receptor 1 (IFNLR1) and the FERM/SH2 Domains of Human JAK1

The crystal structure of a construct consisting of the FERM and SH2-like domains of the human Janus kinase 1 (JAK1) bound to a fragment of the intracellular domain of the interferon-λ receptor 1 (IFNLR1) has been determined at the nominal resolution of 2.1Å. In this structure, the receptor peptide forms an 85-Å-long extended chain, in which both the previously identified box1 and box2 regions bind simultaneously to the FERM and SH2-like domains of JAK1. Both domains of JAK1 are generally well ordered, with regions not seen in the crystal structure limited to loops located away from the receptor-binding regions. The structure provides a much more complete and accurate picture of the interactions between JAK1 and IFNLR1 than those given in earlier reports, illuminating the molecular basis of the JAK-cytokine receptor association. A glutamate residue adjacent to the box2 region in IFNLR1 mimics the mode of binding of a phosphotyrosine in classical SH2 domains. It was shown here that a deletion of residues within the box1 region of the receptor abolishes stable interactions with JAK1, although it was previously shown that box2 alone is sufficient to stabilize a similar complex of the interferon-α receptor and TYK2.

Synergistic production of TNFα and IFNα by human pDCs incubated with IFNλ3 and IL-3

In this study, we investigated whether IFNλ3 and IL-3 reciprocally influence their capacity to activate various functions of human plasmacytoid dendritic cells (pDCs). In fact, we preliminarily observed that IFNλ3 upregulates the expression of the IL-3Rα (CD123), while IL-3 augments the expression of IFNλR1 in pDCs. As a result, we found that combination of IFNλ3 and IL-3 induces a strong potentiation in the production of TNFα, IFNα, as well as in the expression of Interferon-Stimulated Gene (ISG) mRNAs by pDCs, as compared to either IFNλ3 or IL-3 alone. In such regard, we found that endogenous IFNα autocrinally promotes the expression of ISG mRNAs in IL-3-, but not in IFNλ3 plus IL-3-, treated pDCs. Moreover, we uncovered that the production of IFNα by IFNλ3 plus IL-3-treated pDCs is mostly dependent on endogenously produced TNFα. Altogether, our data demonstrate that IFNλ3 and IL-3 collaborate to promote, at maximal levels, discrete functional responses of human pDCs.

The role of IL-29 in immunity and cancer

Interleukin-29 (IL-29) is a new member of the recently discovered interferon λ (IFNλ) family. It is produced predominantly by maturing dendritic cells and macrophages. It has been implicated in numerous immunological responses and has shown antiviral activity similar to the Type I interferons, although its target cell population is more limited than the Type I interferons. In recent years, the role of IL-29 in the pathogenesis of various cancers has also been extensively studied. In this review, we will discuss the recent advances of IL-29 in immunological processes and the pathogenesis of various cancer.

IFN-stimulated gene expression is independent of the IFNL4 genotype in chronic HIV-1 infection

This study aimed to evaluate the association between the IFNL4 rs368234815 (ΔG/TT) dinucleotide polymorphism and the IFN response during chronic HIV-1 infection. We carried out genotyping analysis and measured the expression of IFN-stimulated genes (ISGs) (myxovirus resistance protein A [MxA], ISG15, ISG56, apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like [APOBEC] 3F and APOBEC3G) on peripheral blood mononuclear cells collected from naïve and HAART-treated HIV-1-infected patients. There were no statistically significant differences in endogenous ISGs mRNA levels among HIV-1-positive patients bearing different IFNL4 genotypes, suggesting that ISG expression is independent of the IFNL4 genotype in HIV-1 infection.

Anti-tumor immunity elicited by direct intratumoral administration of a recombinant adenovirus expressing either IL-28A/IFN-λ2 or IL-29/IFN-λ1

Interleukin (IL)-28A/interferon (IFN)-λ2 and IL-29/IFN-λ1 have been demonstrated to elicit direct and indirect anti-tumor actions. In this study, we constructed an adenovirus vector expressing either IL-28A/IFN-λ2 (AdIL-28A) or IL-29/IFN-λ1 (AdIL-29) to evaluate the therapeutic properties of intratumoral injection of recombinant adenovirus to apply for the clinical implementation of cancer gene therapy. Despite the lack of an anti-proliferative effect on MCA205 and B16-F10 cells, a retarded growth of established subcutaneous tumors was observed following multiple injections of either AdIL-28A or AdIL-29 when compared with AdNull. In vivo cell depletion experiments displayed that both NK cells and CD8(+) T cells have a major role in AdIL-28A-mediated tumor growth suppression. A significant increase in the number of infiltrating CD8(+) T cells into the tumors treated with either AdIL-28A or AdIL-29 was observed. Moreover, specific anti-tumor cytotoxic T lymphocyte reactivity was detected in spleen cells from animals treated with either AdIL-28A or AdIL-29. In IFN-γ-deficient mice, anti-tumor activities of AdIL-28A were completely impaired, indicating that IFN-γ is critically involved in the tumor growth inhibition triggered by AdIL-28A. IL-12 provided a synergistic anti-tumor effect when combined with AdIL-28A. These results indicate that AdIL-28A and AdIL-29 could be successfully utilized as an alternative cancer immunogene therapy.

Neuromedin U is upregulated by Snail at early stages of EMT in HT29 colon cancer cells

BACKGROUND

The epithelial-mesenchymal transition (EMT) is considered a core process that facilitates the escape of cancer cells from the primary tumor site. The transcription factor Snail was identified as a key regulator of EMT; however, the cascade of regulatory events leading to metastasis remains unknown and new predictive markers of the process are awaited.

METHODS

Gene expressions were analysed using real-time PCR, protein level by Western immunoblotting and confocal imaging. The motility of the cells was examined using time-lapse microscopy. Affymetrix GeneChip Human Genome U133 Plus 2.0 analysis was performed to identify transcriptomic changes upon Snail. Snail silencing was performed using siRNA nucleofection. NMU detection was performed by ELISA.

RESULTS

HT29 cells overexpressing Snail showed changed morphology, functions and transcriptomic profile indicating EMT induction. Changes in expression of 324 genes previously correlated with cell motility were observed. Neuromedin U was the second highest upregulated gene in HT29-Snail cells. This increase was validated by real-time PCR. Additionally elevated NMU protein was detected by ELISA in cell media.

CONCLUSIONS

These results show that Snail in HT29 cells regulates early phenotype conversion towards an intermediate epithelial state. We provided the first evidence that neuromedin U is associated with Snail regulatory function of metastatic induction in colon cancer cells.

GENERAL SIGNIFICANCE

We described the global, early transcriptomic changes induced through Snail in HT29 colon cancer cells and suggested NMU involvement in this process.

Interleukin-29 Enhances Synovial Inflammation and Cartilage Degradation in Osteoarthritis

We have recently shown that IL-29 was an important proinflammatory cytokine in pathogenesis of rheumatoid arthritis (RA). Inflammation also contributes to the pathogenesis of osteoarthritis (OA). The aim of this study was to investigate the effect and mechanism of IL-29 on cytokine production and cartilage degradation in OA. The mRNA levels of IL-29 and its specific receptor IL-28Ra in peripheral blood mononuclear cells (PBMCs) were significantly increased in OA patients when compared to healthy controls (HC). In the serum, IL-29 protein levels were higher in OA patients than those in HC. Immunohistochemistry revealed that both IL-29 and IL-28Ra were dramatically elevated in OA synovium compared to HC; synovial fibroblasts (FLS) and macrophages were the main IL-29-producing cells in OA synovium. Furthermore, recombinant IL-29 augmented the mRNA expression of IL-1β, IL-6, IL-8, and matrix-metalloproteinase-3 (MMP-3) in OA FLS and increased cartilage degradation when ex vivo OA cartilage explant was coincubated with OA FLS. Finally, in OA FLS, IL-29 dominantly activated MAPK and nuclear factor-κB (NF-κB), but not Jak-STAT and AKT signaling pathway as examined by western blot. In conclusion, IL-29 stimulates inflammation and cartilage degradation by OA FLS, indicating that this cytokine is likely involved in the pathogenesis of OA.