Interleukin-1β exacerbates disease and is a potential therapeutic target to reduce pulmonary inflammation during severe influenza A virus infection

Interleukin 1β receptor and synaptic dysfunction in recurrent brain infection with Herpes simplex virus type-1

Several experimental evidence suggests a link between brain Herpes simplex virus type-1 infection and the occurrence of Alzheimer's disease. However, the molecular mechanisms underlying this association are not completely understood. Among the molecular mediators of synaptic and cognitive dysfunction occurring after Herpes simplex virus type-1 infection and reactivation in the brain neuroinflammatory cytokines seem to occupy a central role. Here, we specifically reviewed literature reports dealing with the impact of neuroinflammation on synaptic dysfunction observed after recurrent Herpes simplex virus type-1 reactivation in the brain, highlighting the role of interleukins and, in particular, interleukin 1β as a possible target against Herpes simplex virus type-1-induced neuronal dysfunctions.

The interplay of co-infections in shaping COVID-19 severity: Expanding the scope beyond SARS-CoV-2

High mortality has been reported in severe cases of COVID-19. Emerging reports suggested that the severity is not only due to SARS-CoV-2 infection, but also due to coinfections by other pathogens exhibiting symptoms like COVID-19. During the COVID-19 pandemic, simultaneous respiratory coinfections with various viral (Retroviridae, Flaviviridae, Orthomyxoviridae, and Picoviridae) and bacterial (Mycobacteriaceae, Mycoplasmataceae, Enterobacteriaceae and Helicobacteraceae) families have been observed. These pathogens intensify disease severity by potentially augmenting SARSCoV-2 replication, inflammation, and modulation of signaling pathways. Coinfection emerges as a critical determinant of COVID-19 severity, principally instigated by heightened pro-inflammatory cytokine levels, as cytokine storm. Thereby, in co-infection scenario, the severity is also driven by the modulation of inflammatory signaling pathways by both pathogens possibly associated with interleukin, interferon, and cell death exacerbating the severity. In the current review, we attempt to understand the role of co- infections by other pathogens and their involvement in the severity of COVID-19.

Immunotherapeutic implications on targeting the cytokines produced in rhinovirus-induced immunoreactions

Rhinovirus is a widespread virus associated with several respiratory diseases, especially asthma exacerbation. Currently, there are no accurate therapies for rhinovirus. Encouragingly, it is found that during rhinovirus-induced immunoreactions the levels of certain cytokines in patients' serum will alter. These cytokines may have pivotal pro-inflammatory or anti-inflammatory effects via their specific mechanisms. Thus far, studies have shown that inhibitions of cytokines such as IL-1, IL-4, IL-5, IL-6, IL-13, IL-18, IL-25, and IL-33 may attenuate rhinovirus-induced immunoreactions, thereby relieving rhinovirus infection. Furthermore, such therapeutics for rhinovirus infection can be applied to viruses of other species, with certain practicability.

Melatonin improves influenza virus infection-induced acute exacerbation of COPD by suppressing macrophage M1 polarization and apoptosis

BACKGROUND

Influenza A viruses (IAV) are extremely common respiratory viruses for the acute exacerbation of chronic obstructive pulmonary disease (AECOPD), in which IAV infection may further evoke abnormal macrophage polarization, amplify cytokine storms. Melatonin exerts potential effects of anti-inflammation and anti-IAV infection, while its effects on IAV infection-induced AECOPD are poorly understood.

METHODS

COPD mice models were established through cigarette smoke exposure for consecutive 24 weeks, evaluated by the detection of lung function. AECOPD mice models were established through the intratracheal atomization of influenza A/H3N2 stocks in COPD mice, and were injected intraperitoneally with melatonin (Mel). Then, The polarization of alveolar macrophages (AMs) was assayed by flow cytometry of bronchoalveolar lavage (BAL) cells. In vitro, the effects of melatonin on macrophage polarization were analyzed in IAV-infected Cigarette smoking extract (CSE)-stimulated Raw264.7 macrophages. Moreover, the roles of the melatonin receptors (MTs) in regulating macrophage polarization and apoptosis were determined using MTs antagonist luzindole.

RESULTS

The present results demonstrated that IAV/H3N2 infection deteriorated lung function (reduced FEV20,50/FVC), exacerbated lung damages in COPD mice with higher dual polarization of AMs. Melatonin therapy improved airflow limitation and lung damages of AECOPD mice by decreasing IAV nucleoprotein (IAV-NP) protein levels and the M1 polarization of pulmonary macrophages. Furthermore, in CSE-stimulated Raw264.7 cells, IAV infection further promoted the dual polarization of macrophages accompanied with decreased MT1 expression. Melatonin decreased STAT1 phosphorylation, the levels of M1 markers and IAV-NP via MTs reflected by the addition of luzindole. Recombinant IL-1β attenuated the inhibitory effects of melatonin on IAV infection and STAT1-driven M1 polarization, while its converting enzyme inhibitor VX765 potentiated the inhibitory effects of melatonin on them. Moreover, melatonin inhibited IAV infection-induced apoptosis by suppressing IL-1β/STAT1 signaling via MTs.

CONCLUSIONS

These findings suggested that melatonin inhibited IAV infection, improved lung function and lung damages of AECOPD via suppressing IL-1β/STAT1-driven macrophage M1 polarization and apoptosis in a MTs-dependent manner. Melatonin may be considered as a potential therapeutic agent for influenza virus infection-induced AECOPD.

Fc-fused IL-7 provides broad antiviral effects against respiratory virus infections through IL-17A-producing pulmonary innate-like T cells

Repeated pandemics caused by the influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV) have resulted in serious problems in global public health, emphasizing the need for broad-spectrum antiviral therapeutics against respiratory virus infections. Here, we show the protective effects of long-acting recombinant human interleukin-7 fused with hybrid Fc (rhIL-7-hyFc) against major respiratory viruses, including influenza virus, SARS-CoV-2, and respiratory syncytial virus. Administration of rhIL-7-hyFc in a therapeutic or prophylactic regimen induces substantial antiviral effects. During an influenza A virus (IAV) infection, rhIL-7-hyFc treatment increases pulmonary T cells composed of blood-derived interferon γ (IFNγ)+ conventional T cells and locally expanded IL-17A+ innate-like T cells. Single-cell RNA transcriptomics reveals that rhIL-7-hyFc upregulates antiviral genes in pulmonary T cells and induces clonal expansion of type 17 innate-like T cells. rhIL-7-hyFc-mediated disease prevention is dependent on IL-17A in both IAV- and SARS-CoV-2-infected mice. Collectively, we suggest that rhIL-7-hyFc can be used as a broadly active therapeutic for future respiratory virus pandemic.

Club cell CREB regulates the goblet cell transcriptional network and pro-mucin effects of IL-1B

Introduction: Club cells are precursors for mucus-producing goblet cells. Interleukin 1β (IL-1B) is an inflammatory mediator with pro-mucin activities that increases the number of mucus-producing goblet cells. IL-1B-mediated mucin production in alveolar adenocarcinoma cells requires activation of the cAMP response element-binding protein (CREB). Whether the pro-mucin activities of IL-1B require club cell CREB is unknown. Methods: We challenged male mice with conditional loss of club cell Creb1 and wild type littermates with intra-airway IL-1B or vehicle. Secondarily, we studied human "club cell-like" H322 cells. Results: IL-1B increased whole lung mRNA of secreted (Mucin 5ac, Mucin 5b) and tethered (Mucin 1, Mucin 4) mucins independent of genotype. However, loss of club cell Creb1 increased whole lung mRNA of member RAS oncogene family (Rab3D), decreased mRNA of the muscarinic receptor 3 (M3R) and prevented IL-1B mediated increases in purinergic receptor P2Y, (P2ry2) mRNA. IL-1B increased the density of goblet cells containing neutral mucins in wildtype mice but not in mice with loss of club cell Creb1. These findings suggested that club cell Creb1 regulated mucin secretion. Loss of club cell Creb1 also prevented IL-1B-mediated impairments in airway mechanics. Four days of pharmacologic CREB inhibition in H322 cells increased mRNA abundance of forkhead box A2 (FOXA2), a repressor of goblet cell expansion, and decreased mRNA expression of SAM pointed domain containing ETS transcription factor (SPDEF), a driver of goblet cell expansion. Chromatin immunoprecipitation demonstrated that CREB directly bound to the promoter region of FOXA2, but not to the promoter region of SPDEF. Treatment of H322 cells with IL-1B increased cAMP levels, providing a direct link between IL-1B and CREB signaling. Conclusion: Our findings suggest that club cell Creb1 regulates the pro-mucin properties of IL-1B through pathways likely involving FOXA2.

Phillyrin ameliorates influenza a virus-induced pulmonary inflammation by antagonizing CXCR2 and inhibiting NLRP3 inflammasome activation

Influenza is an acute viral respiratory illness with high morbidity rates worldwide. Excessive pulmonary inflammation is the main characteristic of lethal influenza A virus (IAV) infections. Therapeutic options for managing influenza are limited to vaccines and some antiviral medications. Phillyrin is one of the major bioactive components of the Chinese herbal medicine Forsythia suspensa, which has the functions of sterilization, heat clearing and detoxification. In this work, the effect and mechanism of phillyrin on H1N1 influenza (PR8)-induced pneumonia were investigated. We reported that phillyrin (15 mg/kg) treatment after viral challenge significantly improved the weight loss, ameliorated pulmonary inflammation and inhibited the accumulation of multiple cytokines and chemokines in bronchoalveolar lavage fluid on 7 days post infection (dpi). In vitro, phillyrin suppressed influenza viral replication (Matrixprotein and nucleoprotein messenger RNA level) and reduced influenza virus-induced cytopathic effect (CPE). Furthermore,chemokine receptor CXCR2 was confirmed to be markedly inhibited by phillyrin. Surface plasmon resonance results reveal that phillyrin exhibits binding affinity to CXCR2, having a binding affinity constant (KD) value of 1.858e-5 M, suggesting that CXCR2 is a potential therapeutic target for phillyrin. Moreover, phillyrin inhibited the mRNA and protein expression levels of Caspase1, ASC and NLRP3 in the lungs of mice with H1N1-induced pneumonia.This study reveals that phillyrin ameliorates IAV-induced pulmonary inflammation by antagonizing CXCR2 and inhibiting NLRP3 inflammasome activation partly.

Gasdermin D promotes hyperinflammation and immunopathology during severe influenza A virus infection

Excessive inflammation and tissue damage during severe influenza A virus (IAV) infection can lead to the development of fatal pulmonary disease. Pyroptosis is a lytic and pro-inflammatory form of cell death executed by the pore-forming protein gasdermin D (GSDMD). In this study, we investigated a potential role for GSDMD in promoting the development of severe IAV disease. IAV infection resulted in cleavage of GSDMD in vivo and in vitro in lung epithelial cells. Mice genetically deficient in GSDMD (Gsdmd-/-) developed less severe IAV disease than wildtype mice and displayed improved survival outcomes. GSDMD deficiency significantly reduced neutrophil infiltration into the airways as well as the levels of pro-inflammatory cytokines TNF, IL-6, MCP-1, and IL-1α and neutrophil-attracting chemokines CXCL1 and CXCL2. In contrast, IL-1β and IL-18 responses were not largely impacted by GSDMD deficiency. In addition, Gsdmd-/- mice displayed significantly improved influenza disease resistance with reduced viral burden and less severe pulmonary pathology, including decreased epithelial damage and cell death. These findings indicate a major role for GSDMD in promoting damaging inflammation and the development of severe IAV disease.

Reactive oxygen species trigger inflammasome activation after intracellular microbial interaction

The intracellular production of reactive oxygen species (ROS), composed of oxygen-reduced molecules, is important not only because of their lethal effects on microorganisms but also due to their potential inflammatory and metabolic regulation properties. The ROS pro-inflammatory properties are associated with the second signal to inflammasome activation, leading to cleaving pro-IL-1β and pro-IL18 before their secretion, as well as gasdermin-D, leading to pyroptosis. Some microorganisms can modulate NLRP3 and AIM-2 inflammasomes through ROS production: whilst Mycobacterium bovis, Mycobacterium kansasii, Francisella novicida, Brucella abortus, Listeria monocytogenes, Influenza virus, Syncytial respiratory virus, Porcine reproductive and respiratory syndrome virus, SARS-CoV, Mayaro virus, Leishmania amazonensis and Plasmodium sp. enhance inflammasome assembly, Hepatitis B virus, Mycobacterium marinum, Mycobacterium tuberculosis, Francisella tularensis and Leishmania sp. disrupt it. This process represents a recent cornerstone in our knowledge of the immunology of intracellular pathogens, which is reviewed in this mini-review.

Immune responses to Tilapia lake virus infection: what we know and what we don't know

Tilapia lake virus (TiLV) is a novel contagious pathogen associated with a lethal disease affecting and decimating tilapia populations on several continents across the globe. Fish viral diseases, such as Tilapia lake virus disease (TiLVD), represent a serious threat to tilapia aquaculture. Therefore, a better understanding of the innate immune responses involved in establishing an antiviral state can help shed light on TiLV disease pathogenesis. Moreover, understanding the adaptive immune mechanisms involved in mounting protection against TiLV could greatly assist in the development of vaccination strategies aimed at controlling TiLVD. This review summarizes the current state of knowledge on the immune responses following TiLV infection. After describing the main pathological findings associated with TiLVD, both the innate and adaptive immune responses and mechanisms to TiLV infection are discussed, in both disease infection models and in vitro studies. In addition, our work, highlights research questions, knowledge gaps and research areas in the immunology of TiLV infection where further studies are needed to better understand how disease protection against TiLV is established.

Transitional dendritic cells are distinct from conventional DC2 precursors and mediate proinflammatory antiviral responses

High-dimensional approaches have revealed heterogeneity amongst dendritic cells (DCs), including a population of transitional DCs (tDCs) in mice and humans. However, the origin and relationship of tDCs to other DC subsets has been unclear. Here we show that tDCs are distinct from other well-characterized DCs and conventional DC precursors (pre-cDCs). We demonstrate that tDCs originate from bone marrow progenitors shared with plasmacytoid DCs (pDCs). In the periphery, tDCs contribute to the pool of ESAM+ type 2 DCs (DC2s), and these DC2s have pDC-related developmental features. Different from pre-cDCs, tDCs have less turnover, capture antigen, respond to stimuli and activate antigen-specific naïve T cells, all characteristics of differentiated DCs. Different from pDCs, viral sensing by tDCs results in IL-1β secretion and fatal immune pathology in a murine coronavirus model. Our findings suggest that tDCs are a distinct pDC-related subset with a DC2 differentiation potential and unique proinflammatory function during viral infections.

Interleukin-1β Disruption Protects Male Mice From Heart Failure With Preserved Ejection Fraction Pathogenesis

Background Heart failure with preserved ejection fraction (HFpEF) is a significant unmet need in cardiovascular medicine and remains an untreatable cardiovascular disease. The role and mechanism of interleukin-1β in HFpEF pathogenesis are poorly understood. Methods and Results C57/Bl6J and interleukin-1β-/- male mice were randomly divided into 4 groups. Groups 1 and 2: C57/Bl6J and interleukin-1β-/- mice were fed a regular diet for 4 months and considered controls. Groups 3 and 4: C57/Bl6 and interleukin-1β-/- mice were fed a high-fat diet with N[w]-nitro-l-arginine methyl ester (endothelial nitric oxide synthase inhibitor, 0.5 g/L) in the drinking water for 4 months. We measured body weight, blood pressure, diabetes status, cardiac function/hypertrophy/inflammation, fibrosis, vascular endothelial function, and signaling. C57/Bl6 fed a high-fat diet and N[w]-nitro-l-arginine methyl ester in the drinking water for 4 months developed HFpEF pathogenesis characterized by obesity, diabetes, hypertension, cardiac hypertrophy, lung edema, low running performance, macrovascular and microvascular endothelial dysfunction, and diastolic cardiac dysfunction but no change in cardiac ejection fraction compared with control mice. Interestingly, the genetic disruption of interleukin-1β protected mice from HFpEF pathogenesis through the modulation of the inflammation and endoplasmic reticulum stress mechanisms. Conclusions Our data suggest that interleukin-1β is a critical driver in the development of HFpEF pathogenesis, likely through regulating inflammation and endoplasmic reticulum stress pathways. Our findings provide a potential therapeutic target for HFpEF treatment.

Naturally derived cytokine peptides limit virus replication and severe disease during influenza A virus infection

Objectives

Novel host‐targeted therapeutics could treat severe influenza A virus (IAV) infections, with reduced risk of drug resistance. LAT8881 is a synthetic form of the naturally occurring C‐terminal fragment of human growth hormone. Acting independently of the growth hormone receptor, it can reduce inflammation‐induced damage and promote tissue repair in an animal model of osteoarthritis. LAT8881 has been assessed in clinical trials for the treatment of obesity and neuropathy and has an excellent safety profile. We investigated the potential for LAT8881, its metabolite LAT9991F and LAT7771 derived from prolactin, a growth hormone structural homologue, to treat severe IAV infection.

Methods

LAT8881, LAT9991F and LAT7771 were evaluated for their effects on cell viability and IAV replication in vitro, as well as their potential to limit disease in a preclinical mouse model of severe IAV infection.

Results

In vitro LAT8881 treatment enhanced cell viability, particularly in the presence of cytotoxic stress, which was countered by siRNA inhibition of host lanthionine synthetase C‐like proteins. Daily intranasal treatment of mice with LAT8881 or LAT9991F, but not LAT7771, from day 1 postinfection significantly improved influenza disease resistance, which was associated with reduced infectious viral loads, reduced pro‐inflammatory cytokines and increased abundance of protective alveolar macrophages. LAT8881 treatment in combination with the antiviral oseltamivir phosphate led to more pronounced reduction in markers of disease severity than treatment with either compound alone.

Conclusion

These studies provide the first evidence identifying LAT8881 and LAT9991F as novel host‐protective therapies that improve survival, limit viral replication, reduce local inflammation and curtail tissue damage during severe IAV infection. Evaluation of LAT8881 and LAT9991F in other infectious and inflammatory conditions of the airways is warranted.

Filaggrin and cytokines in respiratory samples of preterm infants at risk for respiratory viral infection

Respiratory viral infections (RVIs) are frequent in preterm infants possibly inducing long-term impact on respiratory morbidity. Immune response and respiratory barriers are key defense elements against viral insults in premature infants admitted to Neonatal Intensive Care Units (NICUs). Our main goals were to describe the local immune response in respiratory secretions of preterm infants with RVIs during NICU admission and to evaluate the expression and synthesis of lung barrier regulators, both in respiratory samples and in vitro models. Samples from preterm infants that went on to develop RVIs had lower filaggrin gene and protein levels at a cellular level were compared to never-infected neonates (controls). Filaggrin, MIP-1α/CCL3 and MCP-1 levels were higher in pre-infection supernatants compared to controls. Filaggrin, HIF-1α, VEGF, RANTES/CCL5, IL-17A, IL-1β, MIP-1α and MIP-1β/CCL5 levels were higher during and after infection. ROC curve and logistic regression analysis shows that these molecules could be used as infection risk biomarkers. Small airway epithelial cells stimulated by poly:IC presented reduced filaggrin gene expression and increased levels in supernatant. We conclude that filaggrin gene and protein dysregulation is a risk factor of RVI in newborns admitted at the NICU.

Dysregulated Inflammation During Obesity: Driving Disease Severity in Influenza Virus and SARS-CoV-2 Infections

Acute inflammation is a critical host defense response during viral infection. When dysregulated, inflammation drives immunopathology and tissue damage. Excessive, damaging inflammation is a hallmark of both pandemic influenza A virus (IAV) infections and Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) infections. Chronic, low-grade inflammation is also a feature of obesity. In recent years, obesity has been recognized as a growing pandemic with significant mortality and associated costs. Obesity is also an independent risk factor for increased disease severity and death during both IAV and SARS-CoV-2 infection. This review focuses on the effect of obesity on the inflammatory response in the context of viral respiratory infections and how this leads to increased viral pathology. Here, we will review the fundamentals of inflammation, how it is initiated in IAV and SARS-CoV-2 infection and its link to disease severity. We will examine how obesity drives chronic inflammation and trained immunity and how these impact the immune response to IAV and SARS-CoV-2. Finally, we review both medical and non-medical interventions for obesity, how they impact on the inflammatory response and how they could be used to prevent disease severity in obese patients. As projections of global obesity numbers show no sign of slowing down, future pandemic preparedness will require us to consider the metabolic health of the population. Furthermore, if weight-loss alone is insufficient to reduce the risk of increased respiratory virus-related mortality, closer attention must be paid to a patient’s history of health, and new therapeutic options identified.

The Mechanism behind Influenza Virus Cytokine Storm

Influenza viruses are still a serious threat to human health. Cytokines are essential for cell-to-cell communication and viral clearance in the immune system, but excessive cytokines can cause serious immune pathology. Deaths caused by severe influenza are usually related to cytokine storms. The recent literature has described the mechanism behind the cytokine–storm network and how it can exacerbate host pathological damage. Biological factors such as sex, age, and obesity may cause biological differences between different individuals, which affects cytokine storms induced by the influenza virus. In this review, we summarize the mechanism behind influenza virus cytokine storms and the differences in cytokine storms of different ages and sexes, and in obesity.

Too young to die? How aging affects cellular innate immune responses to influenza virus and disease severity

Influenza is a respiratory viral infection that causes significant morbidity and mortality worldwide. The innate immune cell response elicited during influenza A virus (IAV) infection forms the critical first line of defense, which typically is impaired as we age. As such, elderly individuals more commonly succumb to influenza-associated complications, which is reflected in most aged animal models of IAV infection. Here, we review the important roles of several major innate immune cell populations in influenza pathogenesis, some of which being deleterious to the host, and the current knowledge of how age-associated numerical, phenotypic and functional cell changes impact disease development. Further investigation into age-related modulation of innate immune cell responses, using appropriate animal models, will help reveal how immunity to IAV may be compromised by aging and inform the development of novel therapies, tailored for use in this vulnerable group.