Interferon-ß regulates proresolving lipids to promote the resolution of acute airway inflammation.

Aberrant immune responses, including hyperresponsiveness to Toll-like receptor (TLR) ligands, underlie acute respiratory distress syndrome (ARDS). Type I interferons confer antiviral activities and could also regulate the inflammatory response, whereas little is known about their actions to resolve aberrant inflammation. Here we report that interferon-ß (IFN-ß) exerts partially overlapping, but also cooperative actions with aspirin-triggered 15-epi-lipoxin A4 (15-epi-LXA4) and 17-epi-resolvin D1 to counter TLR9-generated cues to regulate neutrophil apoptosis and phagocytosis in human neutrophils. In mice, TLR9 activation impairs bacterial clearance, prolongs Escherichia coli-evoked lung injury, and suppresses production of IFN-ß and the proresolving lipid mediators 15-epi-LXA4 and resolvin D1 (RvD1) in the lung. Neutralization of endogenous IFN-ß delays pulmonary clearance of E. coli and aggravates mucosal injury. Conversely, treatment of mice with IFN-ß accelerates clearance of bacteria, restores neutrophil phagocytosis, promotes neutrophil apoptosis and efferocytosis, and accelerates resolution of airway inflammation with concomitant increases in 15-epi-LXA4 and RvD1 production in the lungs. Pharmacological blockade of the lipoxin receptor ALX/FPR2 partially prevents IFN-ß-mediated resolution. These findings point to a pivotal role of IFN-ß in orchestrating timely resolution of neutrophil and TLR9 activation-driven airway inflammation and uncover an IFN-ß-initiated resolution program, activation of an ALX/FPR2-centered, proresolving lipids-mediated circuit, for ARDS.

The inhibitory effect of DIF-3 on polyinosinic-polycytidylic acid-induced innate immunity activation in human cerebral microvascular endothelial cells.

For the treatment and prevention of autoinflammatory diseases, it is essential to develop the drug, regulating the innate immune system. Although differentiation-inducing factor (DIF) derivatives, extracted from the cellular slime mold, Dictyostelium discoideum, exhibit immunomodulatory effects, their effects on the regulation of innate immunity in brain are unknown. In this study, we used the human cerebral microvascular endothelial cell line, hCMEC/D3, to investigate the effects of DIF derivatives on the generation of C-X-C motif chemokine (CXCL) 10 and interferon (IFN)-ß induced by polyinosinic-polycytidylic acid (poly IC). DIF-3 (1-10 µM), but not DIF-1 and DIF-2, dose-dependently inhibited the biosynthesis of not only CXCL10 but also CXCL16 and C-C motif chemokine 2 induced by poly IC. DIF-3 also strongly decreased IFN-ß mRNA expression and protein release from the cells induced by poly IC through the prohibition of p65, a subtype of NF-ĸB, not interferon regulatory transcription factor 3 phosphorylation. In the docking simulation study, we confirmed that DIF-3 had a high affinity to p65. These results suggest that DIF-3 regulates the innate immune system by inhibiting TLR3/IFN-ß signaling axis through the NF-ĸB phosphorylation inhibition.

Cylindromatosis lysine 63 deubiquitinase (CYLD) suppress TLR3-mediated CCL5 expression in human renal proximal tubular epithelial cells.

BACKGROUND: One of the causes of tubulointerstitial nephritis is viral infection, with innate immune responses affecting its pathogenesis. Toll-like receptor 3 (TLR3) recognizes viral infections and acts antivirally by activating signaling to produce inflammatory cytokines/chemokines, including C-C motif chemokine ligand 5 (CCL5) and interferon-ß (IFN-ß). Although cylindromatosis lysine 63 deubiquitinase (CYLD) is known to be associated with tubulointerstitial nephritis and renal function, its role in the antiviral innate immune response in tubular epithelial cells remains unknown. In this study, we investigated the association between CYLD and TLR3-mediated CCL5 production in cultured human renal proximal tubular epithelial cells (hRPTECs). METHODS AND RESULTS: Polyinosinic-polycytidylic acid (poly IC), a synthetic TLR3 ligand, was used to stimulate hRPTECs. mRNA expression was measured using reverse transcription-quantitative polymerase chain reaction. Protein expression was assayed using western blotting or an enzyme-linked immunosorbent assay. Knockdown of IFN-ß, nuclear factor-kappa B (NF-κB) p65, and CYLD was performed by transfecting cells with specific small interfering RNAs. The intracellular localization of CYLD in hRPTECs was analyzed using immunofluorescence. Poly IC induced CCL5 expression in a time- and concentration-dependent manner, and knockdown of either IFN-ß or p65 reduced poly IC-induced CCL5 expression. CYLD knockdown increased the poly IC-induced CCL5, phosphorylated IκB kinase α/ß (IKK complex), and phosphorylated p65 expression. The CYLD protein was localized in the cytoplasm, and poly IC did not alter its expression. CONCLUSION: CYLD may prevent excessive inflammation due to an antiviral innate immune response by suppressing IKK complex and NF-κB activation downstream of TLR3 in hRPTECs.

Conserved Functions of Orthohepadnavirus X Proteins to Inhibit Type-I Interferon Signaling.

Orthohepadnavirus causes chronic hepatitis in a broad range of mammals, including primates, cats, woodchucks, and bats. Hepatitis B virus (HBV) X protein inhibits type-I interferon (IFN) signaling, thereby promoting HBV escape from the human innate immune system and establishing persistent infection. However, whether X proteins of Orthohepadnavirus viruses in other species display a similar inhibitory activity remains unknown. Here, we investigated the anti-IFN activity of 17 Orthohepadnavirus X proteins derived from various hosts. We observed conserved activity of Orthohepadnavirus X proteins in inhibiting TIR-domain-containing adaptor protein inducing IFN-ß (TRIF)-mediated IFN-ß signaling pathway through TRIF degradation. X proteins from domestic cat hepadnavirus (DCH), a novel member of Orthohepadnavirus, inhibited mitochondrial antiviral signaling protein (MAVS)-mediated IFNß signaling pathway comparable with HBV X. These results indicate that inhibition of IFN signaling is conserved in Orthohepadnavirus X proteins.

Transcriptome Sequencing Reveals Salmonella Flagellin Activation of Interferon-ß-Related Immune Responses in Macrophages.

The flagellin (FliC) of Salmonella typhimurium is a potential vaccine adjuvant as it can activate innate immunity and promote acquired immune responses. Macrophages are an important component of the innate immune system. The mechanism of flagellin's adjuvant activity has been shown to be related to its ability to activate macrophages. However, few studies have comprehensively investigated the effects of Salmonella flagellin in macrophages using transcriptome sequencing. In this study, RNA-Seq was used to analyze the expression patterns of RAW264.7 macrophages induced by FliC to identify novel transcriptomic signatures in macrophages. A total of 2204 differentially expressed genes were found in the FliC-treated group compared with the control. Gene ontology and KEGG pathway analyses identified the top significantly regulated functional classification and canonical pathways, which were mainly related to immune responses and regulation. Inflammatory cytokines (IL-6, IL-1ß, TNF-α, etc.) and chemokines (CXCL2, CXCL10, CCL2, etc.) were highly expressed in RAW264.7 cells following stimulation. Notably, flagellin significantly increased the expression of interferon (IFN)-ß. In addition, previously unidentified IFN regulatory factors (IRFs) and IFN-stimulated genes (ISGs) were also significantly upregulated. The results of RNA-Seq were verified, and furthermore, we demonstrated that flagellin increased the expression of IFN-ß and IFN-related genes (IRFs and ISGs) in bone marrow-derived dendritic cells and macrophages. These results suggested that Salmonella flagellin can activate IFN-ß-related immune responses in macrophages, which provides new insight into the immune mechanisms of flagellin adjuvant.

Redirecting the JAK-STAT signal blocks the SARS-CoV-2 replication.

The distinct disease progression patterns of severe acute respiratory syndrome coronavirus clade 2 (SARS-CoV-2) indicate diverse host immune responses. SARS-CoV-2 severely impairs type I interferon (IFN) cell signaling, resulting in uncontrolled late-phase lung damage in patients. For better pharmacological properties, cytokine modifications may sometimes result in a loss of biological activity against the virus. Here, we employed the genetic code expansion and engineered IFN-ß, a phase II clinical cytokine with 3-amino tyrosine (IFN-ß-A) that reactivates STAT2 expression in virus-infected human cells through JAK/STAT cell signaling without affecting signal activation and serum half-life. This study identified that genetically encoded IFN-ß-A might stabilize the protein-receptor complex and trigger JAK-STAT cell signaling, which is a promising modality for controlling SARS-CoV-2 infection.

Potential of green tea EGCG in neutralizing SARS-CoV-2 Omicron variant with greater tropism toward the upper respiratory tract.

Background: COVID-19 due to SARS-CoV-2 infection has had an enormous adverse impact on global public health. As the COVID-19 pandemic evolves, the WHO declared several variants of concern (VOCs), including Alpha, Beta, Gamma, Delta, and Omicron. Compared with earlier variants, Omicron, now a dominant lineage, exhibits characteristics of enhanced transmissibility, tropism shift toward the upper respiratory tract, and attenuated disease severity. The robust transmission of Omicron despite attenuated disease severity still poses a great challenge for pandemic control. Under this circumstance, its tropism shift may be utilized for discovering effective preventive approaches. Scope and approach: This review aims to estimate the potential of green tea epigallocatechin gallate (EGCG), the most potent antiviral catechin, in neutralizing SARS-CoV-2 Omicron variant, based on current knowledge concerning EGCG distribution in tissues and Omicron tropism. Key findings and conclusions: EGCG has a low bioavailability. Plasma EGCG levels are in the range of submicromolar concentrations following green tea drinking, or reach at most low µM concentrations after pharmacological intervention. Nonetheless, its levels in the upper respiratory tract could reach concentrations as high as tens or even hundreds of µM following green tea consumption or pharmacological intervention. An approach for delivering sufficiently high concentrations of EGCG in the pharynx has been developed. Convincing data have demonstrated that EGCG at tens to hundreds of µM can dramatically neutralize SARS-CoV-2 and effectively eliminate SARS-CoV-2-induced cytopathic effects and plaque formation. Thus, EGCG, which exhibits hyperaccumulation in the upper respiratory tract, deserves closer investigation as an antiviral in the current global battle against COVID-19, given Omicron's greater tropism toward the upper respiratory tract.

1,25(OH)2 D3 blocks IFNß production through regulating STING in epithelial layer of oral lichen planus.

Stimulator of interferon genes (STING) is reported to exert vital functions in inflammatory responses and autoimmune diseases. Nevertheless, the status and roles of STING in oral lichen planus (OLP) remain elusive. Here, we state that STING and its downstream cytokine interferon-ß (IFNß) expression is boosted in the oral keratinocytes from patients suffering OLP in comparison with those from healthy participants. Mechanistically, transcription factor GATA-binding protein 1 (GATA1) which is highly increased in diseased samples specifically interacts with its element in the promoter of STING to enhance STING transcripts. 1,25(OH)2 D3 , the active form of vitamin D, is capable of restricting STING and IFNß increases in oral keratinocyte models resembling OLP in vitro. Moreover, there is a negative correlation between vitamin D receptor (VDR) and STING or IFNß in human samples. Using plasmids and small interfering RNA transfection technologies, we find 1,25(OH)2 D3 regulates STING and IFNß through a mechanism controlled by the hypoxia-inducible factor-1α (HIF-1α)-GATA1 axis. Collectively, our findings unveil that 1,25(OH)2 D3 lowers STING and IFNß overexpression in the context of OLP.

SARS-CoV-2 NSP12 Protein Is Not an Interferon-ß Antagonist.

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is bringing an unprecedented health crisis to the world. To date, our understanding of the interaction between SARS-CoV-2 and host innate immunity is still limited. Previous studies reported that SARS-CoV-2 nonstructural protein 12 (NSP12) was able to suppress interferon-ß (IFN-ß) activation in IFN-ß promoter luciferase reporter assays, which provided insights into the pathogenesis of COVID-19. In this study, we demonstrated that IFN-ß promoter-mediated luciferase activity was reduced during coexpression of NSP12. However, we could show NSP12 did not affect IRF3 or NF-κB activation. Moreover, IFN-ß production induced by Sendai virus (SeV) infection or other stimulus was not affected by NSP12 at mRNA or protein level. Additionally, the type I IFN signaling pathway was not affected by NSP12, as demonstrated by the expression of interferon-stimulated genes (ISGs). Further experiments revealed that different experiment systems, including protein tags and plasmid backbones, could affect the readouts of IFN-ß promoter luciferase assays. In conclusion, unlike as previously reported, our study showed SARS-CoV-2 NSP12 protein is not an IFN-ß antagonist. It also rings the alarm on the general usage of luciferase reporter assays in studying SARS-CoV-2. IMPORTANCE Previous studies investigated the interaction between SARS-CoV-2 viral proteins and interferon signaling and proposed that several SARS-CoV-2 viral proteins, including NSP12, could suppress IFN-ß activation. However, most of these results were generated from IFN-ß promoter luciferase reporter assay and have not been validated functionally. In our study, we found that, although NSP12 could suppress IFN-ß promoter luciferase activity, it showed no inhibitory effect on IFN-ß production or its downstream signaling. Further study revealed that contradictory results could be generated from different experiment systems. On one hand, we demonstrated that SARS-CoV-2 NSP12 could not suppress IFN-ß signaling. On the other hand, our study suggests that caution needs to be taken with the interpretation of SARS-CoV-2-related luciferase assays.

Hepatitis B virus X gene impacts on the innate immunity and immune-tolerant phase in chronic hepatitis B virus infection.

BACKGROUND AND AIMS: The immunologic features involved in the immune-tolerant phase of chronic hepatitis B (CHB) virus (HBV) infection are unclear. The hepatitis B virus X (HBx) protein disrupts IFN-ß induction by downregulating MAVS and may destroy subsequent HBV-specific adaptive immunity. We aimed to analyse the impacts of genetic variability of HBx in CHB patients on the immune-tolerant phase during long-term follow-up. METHODS: Children with CHB in the immune-tolerant phase were recruited and followed longitudinally. HBx gene sequencing of infecting HBV strains was performed, and the effects of HBx mutations on the immune-tolerant phase were assessed. Restoration of the host immune response to end the immune-tolerant phase was investigated by immunoblotting, immunostaining, ELISA and reporter assays of MAVS/IFN-ß signalling in liver cell lines, patient liver tissues and the HBV plasmid replication system. RESULTS: A total of 173 children (median age, 6.92 years) were recruited. Patients carrying HBx R87G, I127V and R87G + I127V double mutations exhibited higher cumulative incidences of immune-tolerant phase breakthrough (p = .011, p = .006 and p = .017 respectively). Cells transfected with HBx R87G and I127V mutants and pHBV1.3-B6.3 replicons containing the HBx R87G and I127V mutations exhibited statistically increased levels of IFN-ß, especially under poly(I:C) stimulation or Flag-MAVS cotransfection. HA-HBx wild-type interacted with Flag-MAVS and enhanced its ubiquitination, but this ability was diminished in the R87G and I127V mutants. CONCLUSIONS: HBx suppresses IFN-ß induction. R87G and I127V mutation restored IFN-ß production by preventing MAVS degradation, contributing to curtailing the HBV immune-tolerant phase in CHB patients.

Elucidation of the inhibitory effect of (+)-hopeaphenol on polyinosinic-polycytidylic acid-induced innate immunity activation in human cerebral microvascular endothelial cells.

Drug development for regulating the innate immune system is important for the prevention and treatment of autoinflammatory and autoimmune diseases. In this context, we investigated the effect of resveratrol derivatives on the inflammatory reactions in the brain. Resveratrol, which can be found in Vitis plants in the form of oligomers, exhibits neuroprotective effects; however, its regulatory effects on innate immunity are still unclear. We examined the effects of (+)-hopeaphenol, a resveratrol tetramer, and its derivatives on the polyinosinic-polycytidylic acid (poly IC)-induced production of interferon (IFN)-ß and C-X-C motif chemokine 10 (CXCL10) in the cultured human cerebral microvascular endothelial cell line hCMEC/D3. (+)-Hopeaphenol (1-10 µM) inhibited the poly IC-induced production of not only CXCL10 but also retinoic acid-inducible gene-I in a dose-dependent manner and significantly reduced the poly IC-induced IFN-ß gene expression and protein release from hCMEC/D3 cells by inhibiting the phosphorylation of p65 but not that of the interferon regulatory transcription factor IRF3. A docking study indicated a high affinity of (+)-hopeaphenol for p65. These results suggest that (+)-hopeaphenol can regulate the innate immune system by inhibiting the poly IC/IFN-ß/CXCL10 signaling axis via suppression of the phosphorylation of the transcription factor NF-ĸB.

Benzyl-para-di-[5-methyl-4-(n-octylamino) pyrimidin-2(1H)one] as an interferon beta (IFN-ß) modulator.

IFN-ß is a cytokine that plays a significant role in the immune system. Inhibition of IFN-ß might be used as a therapeutic approach to treat septic shock. A peptidomimetic previously developed by our research team, 1-benzyl-5-methyl-4-(n-octylamino)pyrimidin-2(1H)-one (LT87), was used as an cardioprotective agent in a myocardial ischemia (MI) mouse model. We have developed new LT87 derivatives by synthetizing its dimers in an attempt to extend its structural variety and enhance its biological activity. A dimeric derivative, LT127, exhibited a dose-dependent inhibition of LPS-mediated IFN-ß and subsequent CXCL10 mRNA transcription. The effect was selective and transduced through TLR4- and TRAM/TRIF-mediated signaling, with no significant effect on MyD88-dependent signaling. However, this effect was not specific to TLR4, since a similar effect was observed both on TLR8- and MDA5/RIG-I-stimulated IFN-ß expression. Nevertheless, LT127 might serve as a drug candidate, specifically as an inhibitor for IFN-ß production in order to develop a novel therapeutic approach to prevent septic shock.

Interdependency of NINJ2 gene expression and polymorphism with susceptibility and response to interferon beta in patients with multiple sclerosis.

OBJECTIVE: Multiple sclerosis (MS) is a multifactorial inflammatory and autoimmune condition that lead to chronic neurodegeneration and central nervous system (CNS) demyelination that mainly affects young adults. The incidence and prevalence rate of MS considerably vary in ethnicities and geographic regions and affecting women more than men. Interferon-ß (IFN-ß) is the first-line disease management for MS, while the majority of affected members does not respond to the IFN-ß. Numerous recent studies shown a significant relationship between genetic variations and responsiveness to the IFN-ß. Therefore, determining the genetic differences in the drug response could help determine precise treatment strategies. METHODS: The genotyping of the rs7298096 polymorphism (SNP) and NINJ2 gene expression were assessed in 99 responders and 106 non-responder patients with IFN-ß treated RRMS. RESULTS: The distribution of rs7298096 SNP was significantly different in the responders and non-responder patients and the NINJ2 gene expression considerably increased in the non-responder patients compare to the responders. The NINJ2 gene expression level in the AA genotype of the non-responder group was higher than to the other genotypes of both groups. CONCLUSION: Our results showed that the NINJ2 gene expression level and rs7298096 genotype possibly affect the response to the IFN-ß in patients with RRMS.

Interferon-ß Plays a Detrimental Role in Experimental Traumatic Brain Injury by Enhancing Neuroinflammation That Drives Chronic Neurodegeneration.

DNA damage and type I interferons (IFNs) contribute to inflammatory responses after traumatic brain injury (TBI). TBI-induced activation of microglia and peripherally-derived inflammatory macrophages may lead to tissue damage and neurological deficits. Here, we investigated the role of IFN-ß in secondary injury after TBI using a controlled cortical impact model in adult male IFN-ß-deficient (IFN-ß-/-) mice and assessed post-traumatic neuroinflammatory responses, neuropathology, and long-term functional recovery. TBI increased expression of DNA sensors cyclic GMP-AMP synthase and stimulator of interferon genes in wild-type (WT) mice. IFN-ß and other IFN-related and neuroinflammatory genes were also upregulated early and persistently after TBI. TBI increased expression of proinflammatory mediators in the cortex and hippocampus of WT mice, whereas levels were mitigated in IFN-ß-/- mice. Moreover, long-term microglia activation, motor, and cognitive function impairments were decreased in IFN-ß-/- TBI mice compared with their injured WT counterparts; improved neurological recovery was associated with reduced lesion volume and hippocampal neurodegeneration in IFN-ß-/- mice. Continuous central administration of a neutralizing antibody to the IFN-α/ß receptor (IFNAR) for 3 d, beginning 30 min post-injury, reversed early cognitive impairments in TBI mice and led to transient improvements in motor function. However, anti-IFNAR treatment did not improve long-term functional recovery or decrease TBI neuropathology at 28 d post-injury. In summary, TBI induces a robust neuroinflammatory response that is associated with increased expression of IFN-ß and other IFN-related genes. Inhibition of IFN-ß reduces post-traumatic neuroinflammation and neurodegeneration, resulting in improved neurological recovery. Thus, IFN-ß may be a potential therapeutic target for TBI.SIGNIFICANCE STATEMENT TBI frequently causes long-term neurological and psychiatric changes in head injury patients. TBI-induced secondary injury processes including persistent neuroinflammation evolve over time and can contribute to chronic neurological impairments. The present study demonstrates that TBI is followed by robust activation of type I IFN pathways, which have been implicated in microglial-associated neuroinflammation and chronic neurodegeneration. We examined the effects of genetic or pharmacological inhibition of IFN-ß, a key component of type I IFN mechanisms to address its role in TBI pathophysiology. Inhibition of IFN-ß signaling resulted in reduced neuroinflammation, attenuated neurobehavioral deficits, and limited tissue loss long after TBI. These preclinical findings suggest that IFN-ß may be a potential therapeutic target for TBI.

Molecular characterization and functional analysis of duck CCCH-type zinc finger antiviral protein (ZAP).

This is the first study to clone duck CCCH-type zinc finger antiviral protein (duZAP) from Jingjiang duck (Anas platyrhynchos). Full-length duZAP cDNA was 2154 bp and encoded a 717-amino acid polypeptide containing four highly conserved CCCH-type finger motifs, a WWE domain and a poly (ADP-ribose) polymerase (PARP) domain. duZAP was expressed in multiple duck tissues, with the highest mRNA expression in the spleen. Overexpression of duZAP in duck embryo fibroblast cells (DEFs) led to activation of the transcription factors IRF1 and NF-κB, and induction of IFN-ß. Analysis of deletion mutants revealed that both the WWE and PARP domains of duZAP were essential for activating the IFN-ß promoter. Knockdown of duZAP in DEFs significantly reduced poly (I:C)- and duck Tembusu virus (DTMUV)-induced IFN-ß activation. Our findings further the understanding of the role of duZAP in the duck innate immune response.

Cathepsin H deficiency decreases hypoxia-ischemia-induced hippocampal atrophy in neonatal mice through attenuated TLR3/IFN-ß signaling.

BACKGROUND: Cathepsin H (CatH) is a lysosomal cysteine protease with a unique aminopeptidase activity. Its expression level is increased in activated immune cells including dendritic cells, macrophages, and microglia. We have previously reported that CatH deficiency impairs toll-like receptor 3 (TLR3)-mediated activation of interferon regulatory factor 3 (IRF3), and the subsequent secretion of interferon (IFN)-ß from dendritic cells. Furthermore, there is increasing evidence that IFN-ß secreted from microglia/macrophages has neuroprotective effects. These observations prompted further investigation into the effects of CatH deficiency on neuropathological changes. METHODS: In this study, neuropathological changes were examined using histochemical staining (both hematoxylin-eosin (H&E) and Nissl) of the hippocampus of wild-type (WT) and CatH-deficient (CatH-/-) mice after hypoxia-ischemia (HI). The density and the localization of CatH and TLR3 were examined by immunofluorescent staining. CatH processing in microglia was assayed by pulse-chase experiments, while immunoblotting was used to examine TLR3 expression and IRF3 activation in microglia/macrophages in the presence of poly(I:C). Microglial cell death was examined by fluorescence-activated cell sorting (FACS), and primary astrocyte proliferation in the presence of IFN-ß was examined using scratch wound assay. RESULTS: WT mice displayed severe atrophy in association with neuronal death and moderate astrogliosis in the hippocampus following neonatal HI. Somewhat surprisingly, CatH-/- mice showed marked neuronal death without severe atrophy in the hippocampus following HI. Furthermore, there was notable microglia/macrophages cell death and strong astrogliosis in the hippocampus. The TLR3 and phosphorylated IRF3 expression level in the hippocampus or splenocytes (mainly splenic macrophages); from CatH-/- mice was lower than in WT mice. In vitro experiments demonstrated that recombinant IFN-ß suppressed HI-induced microglial cell death and astrocyte proliferation. CONCLUSION: These observations suggest that CatH plays a critical role in the proteolytic maturation and stabilization of TLR3, which is necessary for IFN-ß production. Therefore, impaired TLR3/IFN-ß signaling resulting from CatH deficiency may induce microglial cell death after activation and astrogliosis/glial scar formation in the hippocampus following HI injury, leading to suppression of hippocampal atrophy.

Middle East Respiratory Syndrome Coronavirus Nucleocapsid Protein Suppresses Type I and Type III Interferon Induction by Targeting RIG-I Signaling.

Type I and type III interferons (IFNs) are the frontline of antiviral defense mechanisms that trigger hundreds of downstream antiviral genes. In this study, we observed that MERS-CoV nucleocapsid (N) protein suppresses type I and type III IFN gene expression. The N protein suppresses Sendai virus-induced IFN-ß and IFN-λ1 by reducing their promoter activity and mRNA levels, as well as downstream IFN-stimulated genes (ISGs). Retinoic acid-inducible gene I (RIG-I) is known to recognize viral RNA and induce IFN expression through tripartite motif-containing protein 25 (TRIM25)-mediated ubiquitination of RIG-I caspase activation and recruitment domains (CARDs). We discovered that MERS-CoV N protein suppresses RIG-I-CARD-induced, but not MDA5-CARD-induced, IFN-ß and IFN-λ1 promoter activity. By interacting with TRIM25, N protein impedes RIG-I ubiquitination and activation and inhibits the phosphorylation of transcription factors IFN-regulatory factor 3 (IRF3) and NF-κB that are known to be important for IFN gene activation. By employing a recombinant Sindbis virus-EGFP replication system, we showed that viral N protein downregulated the production of not only IFN mRNA but also bioactive IFN proteins. Taken together, MERS-CoV N protein functions as an IFN antagonist. It suppresses RIG-I-induced type I and type III IFN production by interfering with TRIM25-mediated RIG-I ubiquitination. Our study sheds light on the pathogenic mechanism of how MERS-CoV causes disease.IMPORTANCE MERS-CoV causes death of about 35% of patients. Published studies showed that some coronaviruses are capable of suppressing interferon (IFN) expression in the early phase of infection and MERS-CoV proteins can modulate host immune response. In this study, we demonstrated that MERS-CoV nucleocapsid (N) protein suppresses the production of both type I and type III IFNs via sequestering TRIM25, an E3 ubiquitin ligase that is essential for activating the RIG-I signaling pathway. Ectopic expression of TRIM25 rescues the suppressive effect of the N protein. In addition, the C-terminal domain of the viral N protein plays a pivotal role in the suppression of IFN-ß promoter activity. Our findings reveal how MERS-CoV evades innate immunity and provide insights into the interplay between host immune response and viral pathogenicity.

In cardiac fibroblasts, interferon-beta attenuates differentiation, collagen synthesis, and TGF-ß1-induced collagen gel contraction.

Cardiac fibroblasts (CF) play a key role in the homeostasis of the extracellular matrix in cardiac tissue and are newly recognized as inflammatory supporter cells. Besides, CF-to-Cardiac myofibroblast differentiation is commanded by TGF-b, through SMAD signaling pathways, and these last cells are strongly implicated in cardiac fibrosis. In the heart IFN-ß is produced by CF; however, the role of IFN-ß, STAT proteins, and STAT-homo or heterodimers in the regulation of CF function with or without a fibrotic environment is unknown. CF were isolated from hearts of adult rats, and by western blot analysis we studied STAT1, STAT2, and STAT3 phosphorylation and through specific siRNA against these proteins we analyzed their role in CF functions such as differentiation (α-SMA expression); and pro-collagen type-I synthesis and secretion expression levels; collagen gels contraction and CF migration. In cultured adult rats CF, IFN-ß increases phosphorylation of STAT1, STAT2, and STAT3. Both STAT1 and STAT2 were involved in decreasing α-SMA and CF migration induced by TGF-ß1. Also, IFN-ß through STAT1 regulated pro-collagen type-I protein expression levels, and collagen gels contraction induced by TGF-ß1. STAT3 was not involved in any effects of IFN-ß studied. In conclusion, IFN-ß through STAT1 and STAT2 shows antifibrotic effects on CF TGF-ß1-treated, whereas STAT3 did not participate in such effect.

Combination chemoradiotherapy with temozolomide, vincristine, and interferon-ß might improve outcomes regardless of O6-methyl-guanine-DNA-methyltransferase (MGMT) promoter methylation status in newly glioblastoma.

BACKGROUND: This investigator-initiated, open-label, single-arm, single-institute study was conducted to investigate the effectiveness of induction combination chemoradiotherapy and long-term maintenance therapy with temozolomide (TMZ) plus interferon (IFN)-ß for glioblastoma. METHODS: The initial induction combination chemoradiotherapy comprised radiotherapy plus TMZ plus vincristine plus IFN-ß. Maintenance chemotherapy comprised monthly TMZ, continued for 24-50 cycles, plus weekly IFN-ß continued for as long as possible. The primary endpoint was 2-year overall survival (2y-OS). The study protocol was to be considered valid if the expected 2y-OS was over 38% and the lower limit of the 95% confidence interval (CI) was no less than 31.7% compared with historical controls, using Kaplan-Meier methods. Secondary endpoints were median progression-free survival (mPFS), median OS (mOS), 5-year OS rate (5y-OS), and mPFS and mOS classified according to MGMT promoter methylation status. RESULTS: Forty-seven patients were analyzed. The 2y-OS was 40.7% (95%CI, 27.5-55.4%). The mPFS and mOS were 11.0 months and 18.0 months, respectively, and 5y-OS was 20.3% (95%CI, 10.9-34.6%). The mPFS in groups with and without MGMT promoter methylation in the tumor was 10.0 months and 11.0 months (p = 0.59), respectively, and mOS was 24.0 months and 18.0 months (p = 0.88), respectively. The frequency of grade 3/4 neutropenia was 19.1%. CONCLUSIONS: The 2y-OS with induction multidrug combination chemoradiotherapy and long-term maintenance therapy comprising TMZ plus IFN-ß tended to exceed that of historical controls, but the lower limit of the 95%CI was below 31.7%. Although the number of cases was small, this protocol may rule out MGMT promoter methylation status as a prognostic factor. TRIAL REGISTRATION: University Hospital Medical Information Network (number UMIN000040599 ).

The Effect of IFN-ß Treatment on Plasma Levels of BDNF and IL-6 in Relapsing-Remitting Multiple Sclerosis Patients.

BACKGROUND: In recent investigations addressing neurodegenerative diseases, especially multiple sclerosis (MS), the roles of brain-derived neurotrophic factor (BDNF) and interleukin-6 (IL-6) have been examined. METHODS: Forty-five relapsing-remitting MS (RRMS) patients, including 32 IFN-ß-treated and 13 newly identified untreated cases as well as 45 sex- and age-matched healthy controls, were recruited in the study. Plasma levels of BDNF and IL-6 were assessed using the ELISA method. Data were analyzed by SPSS (ver.21). RESULTS: There were significant differences between the case and healthy control groups in terms of the plasma levels of BDNF (p value = 0.044) and IL-6 (p value <0.001). Besides, the treatment with IFN-ß had no significant impact on the level of BDNF or IL-6 in RRMS patients as compared to healthy controls (p value = 0.716 and 0.623 for BDNF and IL-6, respectively). Furthermore, the increase in the plasma levels of BDNF and IL-6 indicated a direct correlation in the case group (r = 0.508, p value = 0.008). In detail, following the classification of the case group into 2 subgroups of IFN-ß-treated and untreated patients, a direct positive correlation was observed between the plasma levels of BDNF and IL-6 in IFN-ß-treated patients (r = 0.495, p value = 0.026). CONCLUSION: The IFN-ß treatment seems not to be effective for upregulating BDNF and IL-6 in RRMS patients.