Type I interferons as anti-inflammatory mediators

Single cell transcriptome profiling reveals pathogenesis of bullous pemphigoid

Bullous pemphigoid (BP) triggers profound functional changes in both immune and non-immune cells in the skin and circulation, though the underlying mechanisms remain unclear. In this study, we conduct single-cell transcriptome analysis of lesional and non-lesional skin, as well as blood samples from BP patients. In lesional skin, non-immune cells upregulate pathways related to metabolism, wound healing, immune activation, and cell migration. LAMP3+DCs from cDC2 show stronger pro-inflammatory signatures than those from cDC1, and VEGFA+ mast cells, crucial for BP progression, are predominantly in lesional skin. As BP patients transition from active to remission stages, blood B cell function shifts from differentiation and memory formation to increased type 1 interferon signaling and reduced IL-4 response. Blood CX3CR1+ ZNF683+ and LAG3+ exhausted T cells exhibit the highest TCR expansion among clones shared with skin CD8+T cells, suggesting their role in fueling skin CD8+T cell clonal expansion. Clinical BP severity correlates positively with blood NK cell IFN-γ production and negatively with amphiregulin (AREG) production. NK cell-derived AREG mitigates IFN-γ-induced keratinocyte apoptosis, suggesting a crucial balance between AREG and IFN-γ in BP progression. These findings highlight functional shifts in BP pathology and suggest potential therapeutic targets.

Ultrastructural Study and Immunohistochemical Characteristics of Mesencephalic Tegmentum in Juvenile Chum Salmon (Oncorhynchus keta) Brain After Acute Traumatic Injury

The ultrastructural organization of the nuclei of the tegmental region in juvenile chum salmon (Oncorhynchus keta) was examined using transmission electron microscopy (TEM). The dorsal tegmental nuclei (DTN), the nucleus of fasciculus longitudinalis medialis (NFLM), and the nucleus of the oculomotor nerve (NIII) were studied. The ultrastructural examination provided detailed ultrastructural characteristics of neurons forming the tegmental nuclei and showed neuro-glial relationships in them. Neurons of three size types with a high metabolic rate, characterized by the presence of numerous mitochondria, polyribosomes, Golgi apparatus, and cytoplasmic inclusions (vacuoles, lipid droplets, and dense bodies), were distinguished. It was found that large interneurons of the NFLM formed contacts with protoplasmic astrocytes. Excitatory synaptic structures were identified in the tegmentum and their detailed characteristic are provided for the first time. Microglia-like cells were found in the NIII. The ultrastructural characteristics of neurogenic zones of the tegmentum of juvenile chum salmon were also determined for the first time. In the neurogenic zones of the tegmentum, adult-type neural stem progenitor cells (aNSPCs) corresponding to cells of types III and IVa Danio rerio. In the neurogenic zones of the tegmentum, neuroepithelial-like cells (NECs) corresponding to cells previously described from the zebrafish cerebellum were found and characterized. In the tegmentum of juvenile chum salmon, patterns of paracrine neurosecretion were observed and their ultrastructural characteristics were recorded. Patterns of apoptosis in large neurons of the tegmentum were examined by TEM. Using immunohistochemical (IHC) labeling of the brain lipid-binding protein (BLBP) and aromatase B (AroB), patterns of their expression in the tegmentum of intact animals and in the post-traumatic period after acute injury to the medulla oblongata were characterized. The response to brainstem injury in chum salmon was found to activate multiple signaling pathways, which significantly increases the BLBP and AroB expression in various regions of the tegmentum and valvula cerebelli. However, post-traumatic patterns of BLBP and AroB localizations are not the same. In addition to a general increase in BLBP expression in the tegmental parenchyma, BLBP overexpression was observed in the rostro-lateral tegmental neurogenic zone (RLTNZ), while AroB expression in the RLTNZ was completely absent. Another difference was the peripheral overexpression of AroB and the formation of dense reactive clusters in the ventro-medial zone of the tegmentum. Thus, in the post-traumatic period, various pathways were activated whose components were putative candidates for inducers of the "astrocyte-like" response in the juvenile chum salmon brain that are similar to those present in the mammalian brain. In this case, BLBP acted as a factor enhancing the differentiation of both radial glia and neurons. Estradiol from AroB+ astrocytes exerted paracrine neuroprotective effects through the potential inhibition of inflammatory processes. These results indicate a new role for neuronal aromatization as a mechanism preventing the development of neuroinflammation. Moreover, our findings support the hypothesis that BLBP is a factor enhancing neuronal and glial differentiation in the post-traumatic period in the chum salmon brain.

Evaluation of salivary stress markers and inflammatory cytokine levels in peri-implantitis patients

BACKGROUND AND OBJECTIVE

Psychological stress has been identified in some observational studies as a potential factor that may modify and affect periodontal diseases, but there are no similar data for peri-implantitis. The aim of this study was to determine the relationship between interleukin (IL)-1β, IL-6, IL-10, interferon (IFN)α inflammatory cytokines and the psychological stress-related markers, glucocorticoid receptor-α (GRα), and salivary α-amylase (sAA) gene expression levels in saliva samples obtained from healthy implants and peri-implantitis patients.

MATERIALS AND METHODS

The study included a total of 50 systemically healthy subjects. Peri-implant clinical parameters were recorded and psychological stress level was evaluated with the hospital anxiety and depression scale (HAD) and state-trait anxiety inventory (STAI) questionnaire forms. Following the evaluations, the patients were divided into 4 groups according their stress and clinical status (Ia, Ib, IIa, IIb). IL-1β, IL-6, IL-10, IFNα, GRα, sAA gene expression levels in the saliva samples were quantified by quantitative polymerase chain reaction (qPCR).

RESULTS

In the group of peri-implantitis who had a high score in stress level assessment scales, significantly higher IL-1β, IL-6, sAA expression levels were observed (p < 0.001). The IL-10 gene expression levels were lower in the groups with a high score in the stress level assessment scales (p < 0.001). GRα gene was expressed at lower levels in the group of peri-implantitis who had a high score in stress level assessment scales but the difference was not statistically significant (p = 0.065).

CONCLUSION

The study findings suggest that psychological stress may increase the inflammation associated with peri-implantitis by affecting cytokine expression levels.

CLINICAL RELEVANCE

To prevent peri-implantitis or reduce its prevalence, it could be beneficial to evaluate stress levels and identify individuals experiencing stress.

Anti-inflammatory roles of type I interferon signaling in the lung

Excessive or persistent inflammation may have detrimental effects on lung structure and function. Currently, our understanding of conserved host mechanisms that control the inflammatory response remains incompletely understood. In this study, we investigated the role of type I interferon signaling in the inflammatory response against diverse clinically relevant stimuli. Using mice deficient in type I interferon signaling (IFNAR1-/-), we demonstrate that the absence of interferon signaling resulted in a robust and persistent inflammatory response against Pseudomonas aeruginosa, lipopolysaccharide, and chemotherapeutic agent bleomycin. The elevated inflammatory response in IFNAR1-/- mice was manifested as elevated myeloid cells, such as macrophages and neutrophils, in the bronchoalveolar lavage. The inflammatory cell response in the IFNAR1-/- mice persisted to 14 days and there is impaired recovery and fibrotic remodeling of the lung in IFNAR1-/- mice after bleomycin injury. In the Pseudomonas infection model, the elevated inflammatory cell response led to improved bacterial clearance in IFNAR1-/- mice, although there was similar lung injury and survival. We performed RNA sequencing of lung tissue in wild-type and IFNAR1-/- mice after LPS and bleomycin injury. Our unbiased analysis identified differentially expressed genes between IFNAR1-/- and wild-type mice, including previously unknown regulation of nucleotide-binding oligomerization domain (NOD)-like receptor signaling, retinoic acid-inducible gene-I (RIG-I) signaling, and necroptosis pathway by type I interferon signaling in both models. These data provide novel insights into the conserved anti-inflammatory mechanisms of the type I interferon signaling.NEW & NOTEWORTHY Type I interferons are known for their antiviral activities. In this study, we demonstrate a conserved anti-inflammatory role of type I interferon signaling against diverse stimuli in the lung. We show that exacerbated inflammatory response in the absence of type I interferon signaling has both acute and chronic consequences in the lung including structural changes.

Cancer-associated fibroblast phenotypes are associated with patient outcome in non-small cell lung cancer

Despite advances in treatment, lung cancer survival rates remain low. A better understanding of the cellular heterogeneity and interplay of cancer-associated fibroblasts (CAFs) within the tumor microenvironment will support the development of personalized therapies. We report a spatially resolved single-cell imaging mass cytometry (IMC) analysis of CAFs in a non-small cell lung cancer cohort of 1,070 patients. We identify four prognostic patient groups based on 11 CAF phenotypes with distinct spatial distributions and show that CAFs are independent prognostic factors for patient survival. The presence of tumor-like CAFs is strongly correlated with poor prognosis. In contrast, inflammatory CAFs and interferon-response CAFs are associated with inflamed tumor microenvironments and higher patient survival. High density of matrix CAFs is correlated with low immune infiltration and is negatively correlated with patient survival. In summary, our data identify phenotypic and spatial features of CAFs that are associated with patient outcome in NSCLC.

Type-I interferons promote innate immune tolerance in macrophages exposed to Mycobacterium ulcerans vesicles

Buruli ulcer is a chronic infectious disease caused by Mycobacterium ulcerans. The pathogen persistence in host skin is associated with the development of ulcerative and necrotic lesions leading to permanent disabilities in most patients. However, few of diagnosed cases are thought to resolve through an unknown self-healing process. Using in vitro and in vivo mouse models and M. ulcerans purified vesicles and mycolactone, we showed that the development of an innate immune tolerance was only specific to macrophages from mice able to heal spontaneously. This tolerance mechanism depends on a type I interferon response and can be induced by interferon beta. A type I interferon signature was further detected during in vivo infection in mice as well as in skin samples from patients under antibiotics regiment. Our results indicate that type I interferon-related genes expressed in macrophages may promote tolerance and healing during infection with skin damaging pathogen.

Short-term exposure to ambient air pollution and COVID-19 severity during SARS-CoV-2 Delta and Omicron waves: A multicenter study

Air pollution may affect the clinical course of respiratory diseases, including COVID-19. This study aimed to evaluate the relationship between exposure of adult patients to mean 24 h levels of particulate matter sized <10 μm (PM₁₀ ) and <2.5 μm (PM_2.5 ) and benzo(a)pyrene (B(a)P) during a week before their hospitalization due to SARS-CoV-2 infection and symptomatology, hyperinflammation, coagulopathy, the clinical course of disease, and outcome. The analyses were conducted during two pandemic waves: (i) dominated by highly pathogenic Delta variant (n = 1440) and (ii) clinically less-severe Omicron (n = 785), while the analyzed associations were adjusted for patient's age, BMI, gender, and comorbidities. The exposure to mean 24 h B(a)P exceeding the limits was associated with increased odds of fever and fatigue as early COVID-19 symptoms, hyperinflammation due to serum C-reactive protein >200 mg/L and interleukin-6 >100 pg/mL, coagulopathy due to  d-dimer >2 mg/L and fatal outcome. Elevated PM₁₀ and PM_{2. 5} levels were associated with higher odds of respiratory symptoms, procalcitonin >0.25 ng/mL and interleukin >100 pg/mL, lower oxygen saturation, need for oxygen support, and death. The significant relationships between exposure to air pollutants and the course and outcomes of COVID-19 were observed during both pandemic waves. Short-term exposure to elevated PM and B(a)P levels can be associated with a worse clinical course of COVID-19 in patients requiring hospitalization and, ultimately, contribute to the health burden caused by SARS-CoV-2 variants of higher and lower clinical significance.

Lipocalin-2 regulates the expression of interferon-stimulated genes and the susceptibility of prostate cancer cells to oncolytic virus infection

Lipocalin-2 (LCN2) performs pleiotropic and tumor context-dependent functions in cancers of diverse etiologies. In prostate cancer (PCa) cells, LCN2 regulates distinct phenotypic features, including cytoskeleton organization and expression of inflammation mediators. Oncolytic virotherapy uses oncolytic viruses (OVs) to kill cancer cells and induce anti-tumor immunity. A main source of specificity of OVs towards tumor cells stems from cancer-induced defects in interferon (IFN)-based cell autonomous immune responses. However, the molecular underpinnings of such defects in PCa cells are only partially understood. Moreover, LCN2 effects on IFN responses of PCa cells and their susceptibility to OVs are unknown. To examine these issues, we queried gene expression databases for genes coexpressed with LCN2, revealing co-expression of IFN-stimulated genes (ISGs) and LCN2. Analysis of human PCa cells revealed correlated expression of LCN2 and subsets of IFNs and ISGs. CRISPR/Cas9-mediated stable knockout of LCN2 in PC3 cells or transient overexpression of LCN2 in LNCaP cells revealed LCN2-mediated regulation of IFNE (and IFNL1) expression, activation of JAK/STAT pathway, and expression of selected ISGs. Accordingly, and dependent on a functional JAK/STAT pathway, LCN2 reduced the susceptibility of PCa cells to infection with the IFN-sensitive OV, EHDV-TAU. In PC3 cells, LCN2 knockout increased phosphorylation of eukaryotic initiation factor 2α (p-eIF2α). Inhibition of PKR-like ER kinase (PERK) in PC3-LCN2-KO cells reduced p-eIF2α while increasing constitutive IFNE expression, phosphorylation of STAT1, and ISG expression; and decreasing EHDV-TAU infection. Together, these data propose that LCN2 regulates PCa susceptibility to OVs through attenuation of PERK activity and increased IFN and ISG expression.

STING-Triggered CNS Inflammation in Human Neurodegenerative Diseases

BACKGROUND

Some neurodegenerative diseases have an element of neuroinflammation that is triggered by viral nucleic acids, resulting in the generation of type I interferons. In the cGAS-STING pathway, microbial and host-derived DNA bind and activate the DNA sensor cGAS, and the resulting cyclic dinucleotide, 2'3-cGAMP, binds to a critical adaptor protein, stimulator of interferon genes (STING), which leads to activation of downstream pathway components. However, there is limited work demonstrating the activation of the cGAS-STING pathway in human neurodegenerative diseases.

METHODS

Post-mortem CNS tissue from donors with multiple sclerosis (n = 4), Alzheimer's disease (n = 6), Parkinson's disease (n = 3), amyotrophic lateral sclerosis (n = 3) and non-neurodegenerative controls (n = 11) were screened by immunohistochemistry for STING and relevant protein aggregates (e.g., amyloid-β, α-synuclein, TDP-43). Human brain endothelial cells were cultured and stimulated with the STING agonist palmitic acid (1-400 μM) and assessed for mitochondrial stress (release of mitochondrial DNA into cytosol, increased oxygen consumption), downstream regulator factors, TBK-1/pIRF3 and inflammatory biomarker interferon-β release and changes in ICAM-1 integrin expression.

RESULTS

In neurodegenerative brain diseases, elevated STING protein was observed mainly in brain endothelial cells and neurons, compared to non-neurodegenerative control tissues where STING protein staining was weaker. Interestingly, a higher STING presence was associated with toxic protein aggregates (e.g., in neurons). Similarly high STING protein levels were observed within acute demyelinating lesions in multiple sclerosis subjects. To understand non-microbial/metabolic stress activation of the cGAS-STING pathway, brain endothelial cells were treated with palmitic acid. This evoked mitochondrial respiratory stress up to a ~2.5-fold increase in cellular oxygen consumption. Palmitic acid induced a statistically significant increase in cytosolic DNA leakage from endothelial cell mitochondria (Mander's coefficient; p < 0.05) and a significant increase in TBK-1, phosphorylated transcription factor IFN regulatory factor 3, cGAS and cell surface ICAM. In addition, a dose response in the secretion of interferon-β was observed, but it failed to reach statistical significance.

CONCLUSIONS

The histological evidence shows that the common cGAS-STING pathway appears to be activated in endothelial and neural cells in all four neurodegenerative diseases examined. Together with the in vitro data, this suggests that the STING pathway might be activated via perturbation of mitochondrial stress and DNA leakage, resulting in downstream neuroinflammation; hence, this pathway may be a target for future STING therapeutics.

Evaluation of the interaction between tumor growth factor-β and interferon type I pathways in patients with COVID-19: focusing on ages 1 to 90 years

BACKGROUND

Evidence revealed that age could affect immune responses in patients with the acute respiratory syndrome of coronavirus 2 (SARS-CoV-2) infection. This study investigated the impact of age on immune responses, especially on the interaction between the tumor growth factor-β (TGF-β) and interferon type-I (IFN-I) axes in the pathogenesis of novel coronavirus disease 2019 (COVID-19).

METHODS

This age-matched case-control investigation enrolled 41 COVID-19 patients and 40 healthy controls categorized into four groups, including group 1 (up to 20 years), group 2 (20-40 years), group 3 (40-60 years), and group 4 (over 60 years). Blood samples were collected at the time of admission. The expression of TGF-βRI, TGF-βRII, IFNARI, IFNARII, interferon regulatory factor 9 (IRF9), and SMAD family member 3 (SMAD3) was measured using the real-time PCR technique. In addition, serum levels of TGF-β, IFN-α, and SERPINE1 were measured by the enzyme-linked immunosorbent assay (ELISA) technique. All biomarkers were measured and analyzed in the four age studies groups.

RESULTS

The expression of TGF-βRI, TGF-βRII, IFNARI, IFNARII, IRF9, and SMAD3 was markedly upregulated in all age groups of patients compared with the matched control groups. Serum levels of IFN-α and SERPINE1 were significantly higher in patient groups than in control groups. While TGF-β serum levels were only significantly elevated in the 20 to 40 and over 60 years patient group than in matched control groups.

CONCLUSIONS

These data showed that the age of patients, at least at the time of admission, may not significantly affect TGF-β- and IFN-I-associated immune responses. However, it is possible that the severity of the disease affects these pathway-mediated responses, and more studies with a larger sample size are needed to verify it.

COVID-19 Spotlights Connections between Disease and Multiple Lifestyle Factors

The SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus 2), and the disease it causes (COVID-19), have had a profound impact on global human society and threaten to continue to have such an impact with newly emerging variants. Because of the widespread effects of SARS-CoV-2, understanding how lifestyle choices impact the severity of disease is imperative. This review summarizes evidence for an involvement of chronic, non-resolving inflammation, gut microbiome disruption (dysbiosis with loss of beneficial microorganisms), and impaired viral defenses, all of which are associated with an imbalanced lifestyle, in severe disease manifestations and post-acute sequelae of SARS-CoV-2 (PASC). Humans' physiological propensity for uncontrolled inflammation and severe COVID-19 are briefly contrasted with bats' low propensity for inflammation and their resistance to viral disease. This insight is used to identify positive lifestyle factors with the potential to act in synergy for restoring balance to the immune response and gut microbiome, and thereby protect individuals against severe COVID-19 and PASC. It is proposed that clinicians should consider recommending lifestyle factors, such as stress management, balanced nutrition and physical activity, as preventative measures against severe viral disease and PASC.

Intrathecal versus Peripheral Inflammatory Protein Profile in MS Patients at Diagnosis: A Comprehensive Investigation on Serum and CSF

Intrathecal inflammation plays a key role in the pathogenesis of multiple sclerosis (MS). To better elucidate its relationship with peripheral inflammation, we investigated the correlation between cerebrospinal fluid (CSF) and serum levels of 61 inflammatory proteins. Paired CSF and serum samples were collected from 143 treatment-naïve MS patients at diagnosis. A customized panel of 61 inflammatory molecules was analyzed by a multiplex immunoassay. Correlations between serum and CSF expression levels for each molecule were performed by Spearman's method. The expression of sixteen CSF proteins correlated with their serum expression (p-value < 0.001): only five molecules (CXCL9, sTNFR2, IFNα2, Pentraxin-3, and TSLP) showed a Rho value >0.40, suggesting moderate CSF/serum correlation. No correlation between inflammatory serum patterns and Q_alb was observed. Correlation analysis of serum expression levels of these sixteen proteins with clinical and MRI parameters pinpointed a subset of five molecules (CXCL9, sTNFR2, IFNα2, IFNβ, and TSLP) negatively correlating with spinal cord lesion volume. However, following FDR correction, only the correlation of CXCL9 remained significant. Our data support the hypothesis that the intrathecal inflammation in MS only partially associates with the peripheral one, except for the expression of some immunomodulators that might have a key role in the initial MS immune response.

Breaking down the cellular responses to type I interferon neurotoxicity in the brain

Since their original discovery, type I interferons (IFN-Is) have been closely associated with antiviral immune responses. However, their biological functions go far beyond this role, with balanced IFN-I activity being critical to maintain cellular and tissue homeostasis. Recent findings have uncovered a darker side of IFN-Is whereby chronically elevated levels induce devastating neuroinflammatory and neurodegenerative pathologies. The underlying causes of these 'interferonopathies' are diverse and include monogenetic syndromes, autoimmune disorders, as well as chronic infections. The prominent involvement of the CNS in these disorders indicates a particular susceptibility of brain cells to IFN-I toxicity. Here we will discuss the current knowledge of how IFN-Is mediate neurotoxicity in the brain by analyzing the cell-type specific responses to IFN-Is in the CNS, and secondly, by exploring the spectrum of neurological disorders arising from increased IFN-Is. Understanding the nature of IFN-I neurotoxicity is a crucial and fundamental step towards development of new therapeutic strategies for interferonopathies.

Emerging Roles of Type-I Interferons in Neuroinflammation, Neurological Diseases, and Long-Haul COVID

Interferons (IFNs) are pleiotropic cytokines originally identified for their antiviral activity. IFN-α and IFN-β are both type I IFNs that have been used to treat neurological diseases such as multiple sclerosis. Microglia, astrocytes, as well as neurons in the central and peripheral nervous systems, including spinal cord neurons and dorsal root ganglion neurons, express type I IFN receptors (IFNARs). Type I IFNs play an active role in regulating cognition, aging, depression, and neurodegenerative diseases. Notably, by suppressing neuronal activity and synaptic transmission, IFN-α and IFN-β produced potent analgesia. In this article, we discuss the role of type I IFNs in cognition, neurodegenerative diseases, and pain with a focus on neuroinflammation and neuro-glial interactions and their effects on cognition, neurodegenerative diseases, and pain. The role of type I IFNs in long-haul COVID-associated neurological disorders is also discussed. Insights into type I IFN signaling in neurons and non-neuronal cells will improve our treatments of neurological disorders in various disease conditions.

Transplantation of human adipose-derived stem cells overexpressing LIF/IFN-β promotes recovery in experimental autoimmune encephalomyelitis (EAE)

Multiple Sclerosis (MS) is the most common demyelinating disease with inflammatory demyelination in the central nerve system. Besides the defect in the myelin repair process, the balance change in inflammatory and anti- inflammatory cytokines is one of the most significant factors in MS pathogenesis. This study aimed at evaluating the effects of co-overexpressing beta interferon (IFN-β) and Leukemia inhibitory factor (LIF) in human adipose-derived stem cells (IFN-β/LIF-hADSCs) on the experimental autoimmune encephalomyelitis (EAE). 12 days after the induction of EAE on female mice C57Bl/6 with MOG35-55 and the emergence of primary clinical signs, the IFN-β/LIF-hADSCs were injected into the mice tail vein of the EAE mice. The mice were sacrificed after 32 days and the spinal cords of the experimental groups were dissected out for the histopathologic and real-time RT-PCR studies. Here, we showed that the clinical scores and infiltration of mononuclear cells of treated mice with IFN-β/LIF-hADSCs were decreased significantly. Demyelination and the number of Olig2⁺ and MBP⁺ cells were significantly increased in the test (IFN-β/LIF-hADSCs) group. The findings revealed that the pattern of inflammatory and anti- inflammatory cytokines gene expression in the IFN-β/LIF-hADSCs group was reversed compared to the control group. Overexpression of LIF as a neurotrophic and IFN-β as an anti-inflammatory cytokine in hADSCs increases the immunomodulatory effect of hADSCs reduces the extent of demyelination, improves the number of Olig2⁺ cells, and also increases the amount of MBP protein which can increase the production of myelin in EAE model. This, besides hADSCs capacity for proliferation and differentiation, might enhance the treatment efficacy and provide a promising candidate for stem cell-based gene therapy of MS therapy in the future.

The association of airborne particulate matter and benzo[a]pyrene with the clinical course of COVID-19 in patients hospitalized in Poland

Air pollution can adversely affect the immune response and increase the severity of the viral disease. The present study aimed to explore the relationship between symptomatology, clinical course, and inflammation markers of adult patients with coronavirus disease 2019 (COVID-19) hospitalized in Poland (n = 4432) and air pollution levels, i.e., mean 24 h and max 24 h level of benzo(a)pyrene (B(a)P) and particulate matter <10 μm (PM₁₀) and <2.5 μm (PM_2.5) during a week before their hospitalization. Exposures to PM_2.5 and B(a)P exceeding the limits were associated with higher odds of early respiratory symptoms of COVID-19 and hyperinflammatory state: interleukin-6 > 100 pg/mL, procalcitonin >0.25 ng/mL, and white blood cells count >11 × 10³/mL. Except for the mean 24 h PM₁₀ level, the exceedance of other air pollution parameters was associated with increased odds for oxygen saturation <90%. Exposure to elevated PM_2.5 and B(a)P levels increased the odds of oxygen therapy and death. This study evidences that worse air quality is related to increased severity of COVID-19 and worse outcome in hospitalized patients. Mitigating air pollution shall be an integral part of measures undertaken to decrease the disease burden during a pandemic of viral respiratory illness.

Anti-Inflammatory Effects of Red Rice Bran Extract Ameliorate Type I Interferon Production via STING Pathway

Type I interferons (IFNs-I) are inflammatory cytokines that play an essential role in the pathogenesis of inflammation and autoimmune diseases. Signaling through nucleic acid sensors causes the production of IFNs-I. A stimulator of interferon genes (STING) is a DNA sensor that signals transduction, leading to the production of IFNs-I after their activation. This study aims to determine the anti-inflammatory effects of red rice bran extract (RRBE) on macrophages through the activation of STING signaling. RAW264.7 macrophage cells were stimulated with STING agonist (DMXAA) with and without RRBE. Cells and supernatant were collected. The level of mRNA expression was determined by qPCR, and inflammatory cytokine production was investigated by ELISA. The results indicate that RRBE significantly lowers the transcription of STING and interferon-stimulated genes (ISGs). Moreover, RRBE suppresses the phosphorylation of STING, leading to a decrease in the expression of Irf3, a transcription factor that initiates IFN-I signaling. Our results provide evidence that red rice bran extract may be a protective compound for inflammatory diseases by targeting STING signaling.

Case Report: Interferon-Alpha-Induced Neuromyelitis Optica Spectrum Disorder

Background and Objectives

To describe a new case of neuromyelitis optica spectrum disorder (NMOSD) induced by the administration of interferon-alpha (IFNα) and to raise awareness of this rare drug-induced disease of IFNα treatment.

Methods

A single case study and comprehensive literature review of eight cases.

Results

A 24-year-old man was diagnosed with cerebral venous thrombosis and essential thrombocythemia. He had been undergoing IFNα treatment (IFNα-2b, 3 million IU per day) without any side effects for 18 months, at which point the patient developed persistent hiccups, nausea, urinary retention, and numbness. Spinal magnetic resonance imaging revealed a longitudinal abnormality extending from the medulla to the entire spinal cord. The patient was positive for anti-aquaporin-4 antibody (AQP4-IgG) in both the serum and cerebrospinal fluid (CSF), which confirmed the diagnosis of NMOSD. Thus, recombinant IFNα-2b was suspended immediately. Because his condition did not improve after 6-day treatment of methylprednisolone pulse therapy (1,000 mg for 3 days, then 500 mg for 3 days), intravenous immunoglobulin (0.4 g/kg/day for 5 days) was administered. The patient gradually improved. Low-dose prednisolone and mycophenolate mofetil were subsequently administered as a long-term treatment. The patient was discharged with subtle limb numbness and their expanded disability status score (EDSS) was 1. At the 1-year follow-up, the patient had not relapsed and tested negative for AQP4-IgG. We further identified the eight patients with IFNα-induced NMOSD. The median onset age was 59 years, and the median time of IFNα exposure was 18 months. Optic neuritis was the most common initial symptom (five, 55.6%), followed by myelitis in three patients and area postrema syndrome in one patient. More than half (five, 55.6%) of the patients were monophasic. After IFNα discontinuation and immunotherapy, most (seven, 77.8%) patients remained relapse-free. However, only one patient was free of sequelae.

Conclusion

This study highlights the potential pathogenic risk of NMOSD of IFNα treatment. Given the high disability rates of this rare drug-induced disease, it is crucial to monitor the early manifestations of NMOSD during IFNα treatment.

Monocyte and Macrophage Lipid Accumulation Results in Down-Regulated Type-I Interferon Responses

Macrophages are critical components of atherosclerotic lesions and their pro- and anti-inflammatory responses influence atherogenesis. Type-I interferons (IFNs) are cytokines that play an essential role in antiviral responses and inflammatory activation and have been shown to promote atherosclerosis. Although the impact of type-I IFNs on macrophage foam cell formation is well-documented, the effect of lipid accumulation in monocytes and macrophages on type-I IFN responses remains unknown. Here we examined IFN stimulated (ISG) and non-ISG inflammatory gene expression in mouse and human macrophages that were loaded with acetylated LDL (acLDL), as a model for foam cell formation. We found that acLDL loading in mouse and human macrophages specifically suppressed expression of ISGs and IFN-β secretion, but not other pro-inflammatory genes. The down regulation of ISGs could be rescued by exogenous IFN-β supplementation. Activation of the cholesterol-sensing nuclear liver X receptor (LXR) recapitulated the cholesterol-initiated type-I IFN suppression. Additional analyses of murine in vitro and in vivo generated foam cells confirmed the suppressed IFN signaling pathways and suggest that this phenotype is mediated via down regulation of interferon regulatory factor binding at gene promoters. Finally, RNA-seq analysis of monocytes of familial hypercholesterolemia (FH) patients also showed type-I IFN suppression which was restored by lipid-lowering therapy and not present in monocytes of healthy donors. Taken together, we define type-I IFN suppression as an athero-protective characteristic of foamy macrophages. These data provide new insights into the mechanisms that control inflammatory responses in hyperlipidaemic settings and can support future therapeutic approaches focusing on reprogramming of macrophages to reduce atherosclerotic plaque progression and improve stability.

Interferons in Pain and Infections: Emerging Roles in Neuro-Immune and Neuro-Glial Interactions

Interferons (IFNs) are cytokines that possess antiviral, antiproliferative, and immunomodulatory actions. IFN-α and IFN-β are two major family members of type-I IFNs and are used to treat diseases, including hepatitis and multiple sclerosis. Emerging evidence suggests that type-I IFN receptors (IFNARs) are also expressed by microglia, astrocytes, and neurons in the central and peripheral nervous systems. Apart from canonical transcriptional regulations, IFN-α and IFN-β can rapidly suppress neuronal activity and synaptic transmission via non-genomic regulation, leading to potent analgesia. IFN-γ is the only member of the type-II IFN family and induces central sensitization and microglia activation in persistent pain. We discuss how type-I and type-II IFNs regulate pain and infection via neuro-immune modulations, with special focus on neuroinflammation and neuro-glial interactions. We also highlight distinct roles of type-I IFNs in the peripheral and central nervous system. Insights into IFN signaling in nociceptors and their distinct actions in physiological vs. pathological and acute vs. chronic conditions will improve our treatments of pain after surgeries, traumas, and infections.

A Hepatitis B Virus-Derived Peptide Can Inhibit Infection of Human Lung Cells with SARS-CoV-2 in a Type-1 Interferon-Dependent Manner

The current COVID-19 pandemic has highlighted the urgent need to develop effective therapeutic strategies. We evaluated the in vitro antiviral effect against SARS-CoV-2 of a hepatitis B virus (HBV) hexamer peptide, Poly6, which is capable of eliciting an antiviral effect against human immunodeficiency virus -1 (HIV-1), as a novel HIV-1 integrase inhibitor, and a strong anticancer immune response in an IFN-I-dependent manner, as a novel potential adjuvant in anticancer immunotherapy. Here, we report that Poly6 exerts an anti-SARS-CoV-2 effect, with an estimated 50% inhibitory concentration of 2.617 µM, in the human bronchial epithelial cell line, Calu-3 but not in Vero-E6 cells, which are deficient in type 1 interferon (IFN-I) signaling. We proved via assays based on mRNA profiles, inhibitors, or blocking antibodies that Poly6 can exert an anti-SARS-CoV-2 effect in an IFN-I-dependent manner. We also found that Poly6 inhibits IL-6 production enhanced by SARS-CoV-2 in infected Calu-3 cells at both the transcription and the translation levels, mediated via IL-10 induction in an IFN-I-dependent manner. These results indicate the feasibility of Poly6 as an IFN-I-inducing COVID-19 drug with potent antiviral and anti-inflammatory activities.

Differential Responses to Targeting Matrix Metalloproteinase 9 in Idiopathic Pulmonary Fibrosis

Rationale: Aberrant lung remodeling in idiopathic pulmonary fibrosis (IPF) is characterized by elevated MMP9 (matrix metalloproteinase 9) expression, but the precise role of this matrix metalloproteinase in this disease has yet to be fully elucidated.Objectives: To evaluate antifibrotic effects of MMP9 inhibition on IPF.Methods: Quantitative genomic, proteomic, and functional analyses both in vitro and in vivo were used to determine MMP9 expression in IPF cells and the effects of MMP9 inhibition on profibrotic mechanisms.Measurements and Main Results: In the present study, we demonstrate that MMP9 expression was increased in airway basal cell (ABC)-like cells from IPF lungs compared with ABC cells from normal lungs. The inhibition of MMP9 activity with an anti-MMP9 antibody, andecaliximab, blocked TGF-β1 (transforming growth factor β1)-induced Smad2 phosphorylation. However, in a subset of cells from patients with IPF, TGF-β1 activation in their ABC-like cells was unaffected or enhanced by MMP9 blockade (i.e., nonresponders). Further analysis of nonresponder ABC-like cells treated with andecaliximab revealed an association with type 1 IFN expression, and the addition of IFNα to these cells modulated both MMP9 expression and TGF-β1 activation. Finally, the inhibition of MMP9 ameliorated pulmonary fibrosis induced by responder lung cells but not a nonresponder in a humanized immunodeficient mouse model of IPF.Conclusions: Together, these data demonstrate that MMP9 regulates the activation of ABC-like cells in IPF and that targeting this MMP might be beneficial to a subset of patients with IPF who show sufficient expression of type 1 IFNs.

Response of human macrophages to gamma radiation is mediated via expression of endogenous retroviruses

Ionizing radiation-induced tissue damage recruits monocytes into the exposed area where they are differentiated to macrophages. These implement phagocytic removal of dying cells and elicit an acute inflammatory response, but can also facilitate tumorigenesis due to production of anti-inflammatory cytokines. Using primary human monocyte-derived macrophages (MDMs) and the THP1 monocytic cell line, we demonstrate that gamma radiation triggers monocyte differentiation toward the macrophage phenotype with increased expression of type I interferons (IFN-I) and both pro- and anti-inflammatory macrophage activation markers. We found that these changes correlate with significantly upregulated expression of 622 retroelements from various groups, particularly of several clades of human endogenous retroviruses (HERVs). Elevated transcription was detected in both sense and antisense directions in the HERV subgroups tested, including the most genetically homogeneous clade HML-2. The level of antisense transcription was three- to five-fold higher than of the sense strand levels. Using a proximity ligation assay and immunoprecipitation followed by RNA quantification, we identified an increased amount of the dsRNA receptors MDA-5 and TLR3 bound to an equivalent number of copies of sense and antisense chains of HERVK HML-2 RNA. This binding triggered MAVS-associated signaling pathways resulting in increased expression of IFN-I and inflammation related genes that enhanced the cumulative inflammatory effect of radiation-induced senescence. HML-2 knockdown was accompanied with reduced expression and secretion of IFNα, pro-inflammatory (IL-1β, IL-6, CCL2, CCL3, CCL8, and CCL20) and anti-inflammatory (IL10) modulators in irradiated monocytes and MDMs. Taken together, our data indicate that radiation stress-induced HERV expression enhances the IFN-I and cytokine response and results in increased levels of pro-inflammatory modulators along with expression of anti-inflammatory factors associated with the macrophage tumorigenic phenotype.

Ionizing radiation is a powerful stressogenic factor that induces massive cell damage. The signals released from radiation-damaged tissues recruit the monocytes, which are differentiated into macrophages that remove dying cells via phagocytosis and facilitate inflammation but can also contribute to tumorigenesis through anti-inflammatory and regenerative activities. The mechanism of this dual response of macrophages to irradiation is not fully understood. Using primary human macrophages and a monocytic cell line, we demonstrated that gamma radiation doses activate expression of various human endogenous retroviruses (HERVs). At the molecular level, we have shown that increased numbers of sense and antisense transcripts of tested HERV subgroups bind to double-stranded RNA receptors inducing the expression of type I interferons, multiple pro-inflammatory and some anti-inflammatory factors. At the phenotypic level, polarized macrophages exhibit a potent inflammatory response along with potentially tumorigenic characteristics. Our data suggest that endogenous retroviruses represent an important contributor of the macrophage-mediated inflammation in response to radiation-induced stress but may also indirectly influence tumorigenesis via biased macrophage polarization.

Vitamin D, zinc and glutamine: Synergistic action with OncoTherad immunomodulator in interferon signaling and COVID‑19 (Review)

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was identified in December, 2019 in Wuhan, China. Since then, it has continued to spread rapidly in numerous countries, while the search for effective therapeutic options persists. Coronaviruses, including SARS-CoV-2, are known to suppress and evade the antiviral responses of the host organism mediated by interferon (IFN), a family of cytokines that plays an important role in antiviral defenses associated with innate immunity, and has been used therapeutically for chronic viral diseases and cancer. On the other hand, OncoTherad, a safe and effective immunotherapeutic agent in the treatment of non-muscle invasive bladder cancer (NMIBC), increases IFN signaling and has been shown to be a promising therapeutic approach for COVID-19 in a case report that described the rapid recovery of a 78-year-old patient with NMIBC with comorbidities. The present review discusses the possible synergistic action of OncoTherad with vitamin D, zinc and glutamine, nutrients that have been shown to facilitate immune responses mediated by IFN signaling, as well as the potential of this combination as a therapeutic option for COVID-19.

A C-terminal peptide from type I interferon protects the retina in a mouse model of autoimmune uveitis

Experimental autoimmune uveitis (EAU) in rodents recapitulates many features of the disease in humans and has served as a useful tool for the development of therapeutics. A peptide from C-terminus of interferon α1, conjugated to palmitoyl-lysine for cell penetration, denoted as IFNα-C, was tested for its anti-inflammatory properties in ARPE-19 cells, followed by testing in a mouse model of EAU. Treatment with IFNα-C and evaluation by RT-qPCR showed the induction of anti-inflammatory cytokines and chemokine. Inflammatory markers induced by treatment with TNFα were suppressed when IFNα-C was simultaneously present. TNF-α mediated induction of NF-κB and signaling by IL-17A were attenuated by IFNα-C. Differentiated ARPE-19 cells were treated with TNFα in the presence or absence IFNα-C and analyzed by immmunhistochemistry. IFNα-C protected against the disruption integrity of tight junction proteins. Similarly, loss of transepithelial resistance caused by TNFα was prevented by IFNα-C. B10.RIII mice were immunized with a peptide from interphotoreceptor binding protein (IRBP) and treated by gavage with IFNα-C. Development of uveitis was monitored by histology, fundoscopy, SD-OCT, and ERG. Treatment with IFNα-C prevented uveitis in mice immunized with the IRBP peptide. Splenocytes isolated from mice with ongoing EAU exhibited antigen-specific T cell proliferation that was inhibited in the presence of IFNα-C. IFNα-C peptide exhibits anti-inflammatory properties and protects mice against damage to retinal structure and function suggesting that it has therapeutic potential for the treatment of autoimmune uveitis.

Two Distinct Immune Pathways Linking Social Relationships With Health: Inflammatory and Antiviral Processes

OBJECTIVE

Social relationships can both influence and be influenced by immune processes. Past work implicates two distinct pathways along which this interaction may occur: inflammatory processes and antiviral processes. This article reviews how social behavior is modulated by these two immune processes and how such processes may in turn regulate social behavior.

METHODS

This narrative review outlines existing work on social behavior and both inflammatory and antiviral processes. We propose an evolutionary framework that aims to integrate these findings. Specifically, social isolation has evolutionarily increased the likelihood of wounding and therefore increased the need for inflammation, which works to promote healing. Conversely, broader social networks provide protection from physical threats but also lead to increased pathogen exposure, necessitating a more robust antiviral response.

RESULTS

This review highlights that social adversity, such as social exclusion or loneliness, is associated with increased inflammation, whereas social contact is associated with increased antiviral immunity. Furthermore, increased inflammation leads to sensitivity to social stimuli, presumably to avoid hostile conspecifics and approach allies who may provide care while vulnerable. Individuals with inadequate antiviral immunity engage in behaviors that minimize pathogen exposure, such as reduced affiliative behavior.

CONCLUSIONS

This review suggests that adverse social experiences (social isolation, perceived social threat) may induce inflammatory responses while suppressing antiviral immunity, whereas positive experiences of social connection may reduce inflammation and bolster antiviral responses. Although acutely elevated inflammation would be adaptive under conditions where wounding is likely, chronic inflammation related to continued social adversity may have detrimental health consequences.

Neuromyelitis optica spectrum disorder occurred after interferon alpha therapy in malignant melanoma

BACKGROUND

Several cases of neuromyelitis optica spectrum disorder (NMOSD) caused by interferon alpha (IFN-α) treatment in hepatitis C were reported in past literatures, but NMOSD resulted from IFN-α treatment in tumor has not yet been reported previously.

METHODS

A unique case of NMOSD caused by IFN-α therapy in malignant melanoma is presented. Related cases about NMOSD caused by IFN-α therapy on Pubmed were reviewed further.

RESULTS

A 40-year-old Chinese woman was diagnosed as right breast skin malignant melanoma and received melanoma resection in April 2012, then underwent IFN-α-2b therapy (5 million IU every time, 3 times/week) from May 2012 to Sep 2016. In December 2016, the patient developed bilateral optic neuritis, with no light perception at her worst. After a month-long glucocorticoid treatment, she could see finger movement from 40 cm. Serum positive anti-AQP-4 antibody was found by enzyme-linked immunosorbent assay (ELISA, 75.9 u/ml) in Feb 2017 and indirect immunofluorescence testing (IIFT, 1:320) in Sep 2017. Methylprednisolone (8 mg/day) and rituximab (0.1 g/every 6 months) were used for prevention. On the follow up visit in Jan 2019, she could see finger movement from 1 m, and no melanoma and NMOSD relapse were complained. Literature review only found 3 cases of NMOSD caused by IFN-α treatment in hepatitis.

CONCLUSIONS

A unique case of NMOSD with positive anti-AQP-4 antibody after IFN-α treatment in malignant melanoma was reported. Type I IFNs may be pro-inflammatory in NMOSD and this possible consequence of IFNs use should be cautioned in future practice.

Sequential conditioning-stimulation reveals distinct gene- and stimulus-specific effects of Type I and II IFN on human macrophage functions

Macrophages orchestrate immune responses by sensing and responding to pathogen-associated molecules. These responses are modulated by prior conditioning with cytokines such as interferons (IFNs). Type I and II IFN have opposing functions in many biological scenarios, yet macrophages directly stimulated with Type I or II IFN activate highly overlapping gene expression programs. We hypothesized that a sequential conditioning-stimulation approach would reveal with greater specificity the differential effects of Type I and II IFN on human macrophages. By first conditioning with IFN then stimulating with toll-like receptor ligands and cytokines, followed by genome-wide RNA-seq analysis, we identified 713 genes whose expression was unaffected by IFN alone but showed potentiated or diminished responses to a stimulus after conditioning. For example, responses to the cytokine TNF were restricted by Type II IFN conditioning but potentiated by Type I IFN conditioning. We observed that the effects of IFN were not uniformly pro- or anti-inflammatory, but highly gene-specific and stimulus-specific. By assessing expression levels of key signal transducers and characterizing chromatin accessibility by ATAC-seq, we identify the likely molecular mechanisms underlying Type I and Type II-specific effects, distinguishing between modulation of cytoplasmic signaling networks and the nuclear epigenome that synergistically regulate macrophage immune responses.

Interferon (IFN)-inducible Absent in Melanoma 2 proteins in the negative regulation of the type I IFN response: Implications for lupus nephritis

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that exhibits a strong female bias (female-to-male ratio 9:1) in patients. Further, 40-60% SLE patients develop lupus nephritis (LN), which significantly increases the mortality rates. The failure of current therapies to adequately treat LN in patients reflects an incomplete understanding of the disease pathogenesis. Notably, a chronic increase in serum interferon-α (IFN-α) activity is a heritable risk factor to develop SLE. Accordingly, blood cells from most SLE patients with an active disease exhibit an increase in the expression of the type I IFN (IFN-α/β)-stimulated genes (ISGs, also referred to as "IFN-signature"), a type I IFN response. Further, LN patients during renal flares also exhibit an "IFN-signature" in renal biopsies. Therefore, an improved understanding of the regulation of type I IFNs expression is needed. Basal levels of the IFN-β through "priming" of IFN-α producing cells augment the expression of the IFN-α genes. Of interest, recent studies have indicated a role for the type I IFN-inducible Absent in Melanoma 2 proteins (the murine Aim2 and human AIM2) in the negative regulation of the type I IFN response through inflammasome-dependent and independent mechanisms. Further, an increase in the expression of Aim2 and AIM2 proteins in kidney and renal macrophages associated with the development of nephritis. Therefore, we discuss the role of Aim2/AIM2 proteins in the regulation of type I IFNs and LN. An improved understanding of the mechanisms by which the Absent in Melanoma 2 proteins suppress the type I IFN response and modulate nephritis is key to identify novel therapeutic targets to treat a group of LN patients.

CD14 Counterregulates Lipopolysacharide-Induced Tumor Necrosis Factor-α Production in a Macrophage Subset

In response to GM-CSF or M-CSF, macrophages (MΦ) can acquire pro- or anti-inflammatory properties, respectively. Given the importance of CD14 and Toll-like receptor (TLR) 4 in lipopolysaccharide (LPS)-induced signaling, we studied the effect of anti-CD14 antibody mediated CD14 blockade on LPS-induced cytokine production, signal transduction and on the expression levels of CD14 and TLR4 in GM-MΦ and M-MΦ. We found M-MΦ to express higher levels of both surface antigens and to produce more interferon (IFN)-β and interleukin-10, but less tumor necrosis factor (TNF)-α than GM-MΦ. Blockage of CD14 at high LPS concentrations increased the production of proinflammatory cytokines and decreased that of IFN-β in M-MΦ but not in GM-MΦ. We show that phosphorylation states of signaling molecules of the MyD88 (myeloid differentiation primary response 88), TRIF (TIR-domain-containing adapter-inducing IFN-β) and MAPK (mitogen-activated protein kinase) pathways are not altered in any way that would account for the cytokine overshoot reaction. However, CD14 blockage in M-MΦ decreased TLR4 and CD14 expression levels, regardless of the presence of LPS, indicating that the loss of the surface molecules prevented LPS from initiating TRIF signaling. As TNF-α synthesis was even upregulated under these experimental conditions, we suggest that TRIF is normally involved in restricting LPS-induced TNF-α overproduction. Thus, surface CD14 plays a decisive role in the biological response by determining LPS-induced signaling.

Host-pathogen kinetics during influenza infection and coinfection: insights from predictive modeling

Influenza virus infections are a leading cause of morbidity and mortality worldwide. This is due in part to the continual emergence of new viral variants and to synergistic interactions with other viruses and bacteria. There is a lack of understanding about how host responses work to control the infection and how other pathogens capitalize on the altered immune state. The complexity of multi-pathogen infections makes dissecting contributing mechanisms, which may be non-linear and occur on different time scales, challenging. Fortunately, mathematical models have been able to uncover infection control mechanisms, establish regulatory feedbacks, connect mechanisms across time scales, and determine the processes that dictate different disease outcomes. These models have tested existing hypotheses and generated new hypotheses, some of which have been subsequently tested and validated in the laboratory. They have been particularly a key in studying influenza-bacteria coinfections and will be undoubtedly be useful in examining the interplay between influenza virus and other viruses. Here, I review recent advances in modeling influenza-related infections, the novel biological insight that has been gained through modeling, the importance of model-driven experimental design, and future directions of the field.

The intracellular pyrimidine 5'-nucleotidase NT5C3A is a negative epigenetic factor in interferon and cytokine signaling

The enzyme pyrimidine 5'-nucleotidase (NT5C3A), which mediates nucleotide catabolism, was previously thought to be restricted to blood cells. We showed that expression of the gene encoding NT5C3A was induced by type I interferons (IFNs) in multiple cell types and that NT5C3A suppressed cytokine production through inhibition of the nuclear factor κB (NF-κB) pathway. NT5C3A expression required both an intronic IFN-stimulated response element and the IFN-stimulated transcription factor IRF1. Overexpression of NT5C3A, but not of its catalytic mutants, suppressed IL-8 production by HEK293 cells. Whereas knockdown of NT5C3A enhanced tumor necrosis factor (TNF)-stimulated IL-8 production, it reduced the IFN-mediated suppression of Il8 expression. Overexpression of NT5C3A increased the abundance of NAD⁺ and the activation of the sirtuins SIRT1 and SIRT6, which are NAD⁺-dependent deacetylases. NT5C3A-stimulated sirtuin activity resulted in deacetylation of histone H3 and the NF-κB subunit RelA (also known as p65), both of which were associated with the proximal region of the Il8 promoter, thus repressing the transcription of Il8 Together, these data identify an anti-inflammatory pathway that depends on the catalytic activity of NT5C3A and functions as a negative feedback regulator of inflammatory cytokine signaling.

Investigations on the molecular mode of action of the novel immunostimulator ZelNate: Activation of the cGAS-STING pathway in mammalian cells

Bovine respiratory disease (BRD) is usually prevented or treated with vaccines and/or antibiotics. The use of antibiotics is, however, of concern due to the potential promotion of microbial resistance and the occurrence of residues. Recently an alternative aid in the treatment of BRD, the cationic lipid/bacterial plasmid DNA liposome-based immunomodulator ZelNate, has entered the veterinary market. In the present study, we provide data on the molecular mode of action of ZelNate. Despite the presence of numerous non-methylated CpG motifs in its plasmid DNA, ZelNate proved to be inactive on human and mouse toll-like receptor 9 (TLR9) in cell culture, in both recombinant and natural cellular receptor settings. However, in the human monocyte cell line THP1 and in the mouse melanoma cell line B16, ZelNate activates strongly the stimulator of interferon genes (STING) pathway, which is known to lead predominantly to interferon response factor 3 (IRF3) activation. Further analysis in THP1 cells suggests that the ZelNate plasmid DNA activates STING via interaction with cyclic guanylate adenylate synthase (cGAS), but not via interferon induced gene 16 (IFI16). Our in vitro observations suggest that ZelNate may act predominantly via the cGAS/STING/IRF3 pathway.

Interferons and inflammasomes: Cooperation and counterregulation in disease

Interferons and the IL-1 family of cytokines have important roles in host defense against invading viruses and bacteria. Inflammasomes, multimeric cytosolic sensors of infection, are required for IL-1β and IL-18 processing and release. Interferons, IL-1β, and IL-18 are also implicated in autoimmune disease and chronic inflammation. Although independent but complementary pathways induce these cytokine subsets during infection, in some circumstances the cross-talk between these key inflammatory mediators is a particular requirement for effective host defense. In this review we will summarize recent discoveries concerning the potentiation of inflammasome responses by type I interferons, particularly in patients with gram-negative bacterial infections, and reflect on the molecular mechanisms of IFN-β's immunosuppressive effects through modulation of inflammasome and IL-1β signaling in patients with tuberculosis and multiple sclerosis.

NUDT2 Disruption Elevates Diadenosine Tetraphosphate (Ap4A) and Down-Regulates Immune Response and Cancer Promotion Genes

Regulation of gene expression is one of several roles proposed for the stress-induced nucleotide diadenosine tetraphosphate (Ap₄A). We have examined this directly by a comparative RNA-Seq analysis of KBM-7 chronic myelogenous leukemia cells and KBM-7 cells in which the NUDT2 Ap₄A hydrolase gene had been disrupted (NuKO cells), causing a 175-fold increase in intracellular Ap₄A. 6,288 differentially expressed genes were identified with P < 0.05. Of these, 980 were up-regulated and 705 down-regulated in NuKO cells with a fold-change ≥ 2. Ingenuity^® Pathway Analysis (IPA^®) was used to assign these genes to known canonical pathways and functional networks. Pathways associated with interferon responses, pattern recognition receptors and inflammation scored highly in the down-regulated set of genes while functions associated with MHC class II antigens were prominent among the up-regulated genes, which otherwise showed little organization into major functional gene sets. Tryptophan catabolism was also strongly down-regulated as were numerous genes known to be involved in tumor promotion in other systems, with roles in the epithelial-mesenchymal transition, proliferation, invasion and metastasis. Conversely, some pro-apoptotic genes were up-regulated. Major upstream factors predicted by IPA^® for gene down-regulation included NFκB, STAT1/2, IRF3/4 and SP1 but no major factors controlling gene up-regulation were identified. Potential mechanisms for gene regulation mediated by Ap₄A and/or NUDT2 disruption include binding of Ap₄A to the HINT1 co-repressor, autocrine activation of purinoceptors by Ap₄A, chromatin remodeling, effects of NUDT2 loss on transcript stability, and inhibition of ATP-dependent regulatory factors such as protein kinases by Ap₄A. Existing evidence favors the last of these as the most probable mechanism. Regardless, our results suggest that the NUDT2 protein could be a novel cancer chemotherapeutic target, with its inhibition potentially exerting strong anti-tumor effects via multiple pathways involving metastasis, invasion, immunosuppression and apoptosis.

miRNAs Participate in MS Pathological Processes and Its Therapeutic Response

Multiple sclerosis is the most common autoimmune disease of the central nervous system. It is believed that the increased migration of autoreactive lymphocytes across the blood-brain barrier (BBB) may be responsible for axonal demyelination of neurons. In this review, we discuss microRNAs participating in the pathological processes of MS, including periphery inflammation, blood-brain barrier disruption, and CNS lesions, and in its therapeutic response, in order to find biomarkers of disease severity and to predict the response to therapy of the diseases.

Induction of endogenous Type I interferon within the central nervous system plays a protective role in experimental autoimmune encephalomyelitis

The Type I interferons (IFN), beta (IFN-β) and the alpha family (IFN-α), act through a common receptor and have anti-inflammatory effects. IFN-β is used to treat multiple sclerosis (MS) and is effective against experimental autoimmune encephalomyelitis (EAE), an animal model for MS. Mice with EAE show elevated levels of Type I IFNs in the central nervous system (CNS), suggesting a role for endogenous Type I IFN during inflammation. However, the therapeutic benefit of Type I IFN produced in the CNS remains to be established. The aim of this study was to examine whether experimentally induced CNS-endogenous Type I IFN influences EAE. Using IFN-β reporter mice, we showed that direct administration of polyinosinic–polycytidylic acid (poly I:C), a potent inducer of IFN-β, into the cerebrospinal fluid induced increased leukocyte numbers and transient upregulation of IFN-β in CD45/CD11b-positive cells located in the meninges and choroid plexus, as well as enhanced IFN-β expression by parenchymal microglial cells. Intrathecal injection of poly I:C to mice showing first symptoms of EAE substantially increased the normal disease-associated expression of IFN-α, IFN-β, interferon regulatory factor-7 and IL-10 in CNS, and disease worsening was prevented for as long as IFN-α/β was expressed. In contrast, there was no therapeutic effect on EAE in poly I:C-treated IFN receptor-deficient mice. IFN-dependent microglial and astrocyte response included production of the chemokine CXCL10. These results show that Type I IFN induced within the CNS can play a protective role in EAE and highlight the role of endogenous type I IFN in mediating neuroprotection.

Type I IFNs as biomarkers in rheumatoid arthritis: towards disease profiling and personalized medicine

RA (rheumatoid arthritis) is a chronic rheumatic condition hallmarked by joint inflammation and destruction by self-reactive immune responses. Clinical management of RA patients is often hampered by its heterogeneous nature in both clinical presentation and outcome, thereby highlighting the need for new predictive biomarkers. In this sense, several studies have recently revealed a role for type I IFNs (interferons), mainly IFNα, in the pathogenesis of a subset of RA patients. Genetic variants associated with the type I IFN pathway have been linked with RA development, as well as with clinical features. Moreover, a role for IFNα as a trigger for RA development has also been described. Additionally, a type I IFN signature has been associated with the early diagnosis of RA and clinical outcome prediction in patients undergoing biological drug treatment, two challenging issues for decision-making in the clinical setting. Moreover, these cytokines have been related to endothelial damage and vascular repair failure in different autoimmune disorders. Therefore, together with chronic inflammation and disease features, they could probably account for the increased cardiovascular disease morbidity and mortality of these patients. The main aim of the present review is to provide recent evidence supporting a role for type I IFNs in the immunopathology of RA, as well as to analyse their possible role as biomarkers for disease management.

Single-cell RNA-seq reveals dynamic paracrine control of cellular variation

High-throughput single-cell transcriptomics offers an unbiased approach for understanding the extent, basis and function of gene expression variation between seemingly identical cells. Here we sequence single-cell RNA-seq libraries prepared from over 1,700 primary mouse bone-marrow-derived dendritic cells spanning several experimental conditions. We find substantial variation between identically stimulated dendritic cells, in both the fraction of cells detectably expressing a given messenger RNA and the transcript's level within expressing cells. Distinct gene modules are characterized by different temporal heterogeneity profiles. In particular, a 'core' module of antiviral genes is expressed very early by a few 'precocious' cells in response to uniform stimulation with a pathogenic component, but is later activated in all cells. By stimulating cells individually in sealed microfluidic chambers, analysing dendritic cells from knockout mice, and modulating secretion and extracellular signalling, we show that this response is coordinated by interferon-mediated paracrine signalling from these precocious cells. Notably, preventing cell-to-cell communication also substantially reduces variability between cells in the expression of an early-induced 'peaked' inflammatory module, suggesting that paracrine signalling additionally represses part of the inflammatory program. Our study highlights the importance of cell-to-cell communication in controlling cellular heterogeneity and reveals general strategies that multicellular populations can use to establish complex dynamic responses.

Interferon tau alleviates obesity-induced adipose tissue inflammation and insulin resistance by regulating macrophage polarization

Chronic adipose tissue inflammation is a hallmark of obesity-induced insulin resistance and anti-inflammatory agents can benefit patients with obesity-associated syndromes. Currently available type I interferons for therapeutic immunomodulation are accompanied by high cytotoxicity and therefore in this study we have examined anti-inflammatory effects of interferon tau (IFNT), a member of the type I interferon family with low cellular toxicity even at high doses. Using a diet-induced obesity mouse model, we observed enhanced insulin sensitivity in obese mice administered IFNT compared to control mice, which was accompanied by a significant decrease in secretion of proinflammatory cytokines and elevated anti-inflammatory macrophages (M2) in adipose tissue. Further investigations revealed that IFNT is a potent regulator of macrophage activation that favors anti-inflammatory responses as evidenced by activation of associated surface antigens, production of anti-inflammatory cytokines, and activation of selective cell signaling pathways. Thus, our study demonstrates, for the first time, that IFNT can significantly mitigate obesity-associated systemic insulin resistance and tissue inflammation by controlling macrophage polarization, and thus IFNT can be a novel bio-therapeutic agent for treating obesity-associated syndromes and type 2 diabetes.

Antibodies against interferon-beta in neuromyelitis optica patients

Neuromyelitis optica (NMO) is an antibody-mediated autoimmune inflammatory disease of the CNS. A poor response to treatment with recombinant interferon beta (IFN-ß) in NMO patients has been suggested, although the precise mechanisms remain uncertain. We analyzed occurrence and clinical consequences of IFN-neutralizing antibodies (NAbs) in 15 IFN-ß treated NMO-patients from a population-based retrospective case series cohort. NMO patients not treated with IFN-ß acted as a reference group. IFN-ß antibody determinations included binding antibodies (BAbs) measured by immunoassay and NAbs measured by a neutralization bioassay. Antibodies were determined 6-36 months after initiation of IFN-β therapy and NAbs additionally 5-10 years post-therapy. BAbs were detected in 14/15 NMO patients; 6/15 were NAbs-positive (3 at 5-10 years post-therapy) two of those anti-AQP4 antibody-positive; seven of the nine NAbs-negative patients were anti-AQP4 antibody-positive. Eleven patients (three NAbs-positive, eight NAbs-negative) developed cerebral lesions and 12 patients (four NAbs-positive, eight NAbs-negative) spinal cord lesions on magnetic resonance imaging as gadolinium positive lesions or T2-weighted lesions, at significantly higher frequencies than NMO reference group (p<0.009). Exacerbation occurred within 90 days in four and 6-36 months in eight patients. Progression of disease activity in NMO patients occurred during IFN-β treatment, irrespective of IFN-neutralizing antibody status.

Interferon alpha association with neuromyelitis optica

Interferon-alpha (IFN-α) has immunoregulatory functions in autoimmune inflammatory diseases. The goal of this study was to determine occurrence and clinical consequences of IFN-α in neuromyelitis optica (NMO) patients. Thirty-six NMO and 41 multiple sclerosis (MS) patients from a population-based retrospective case series were included. Expanded Disability Status Scale (EDSS) score and MRI findings determined disease activity. Linear regression was used to assess the effects of the level of IFN-α on disability (EDSS). IFN-α was determined by sensitive ELISA assays. IFN-α was detectable in sera from 9/36 NMO patients, significantly more often than in the MS group (2/41) (P = 0.0197). A higher frequency of IFN-α was observed in NMO patients with acute relapse compared to NMO patients in remission (P < 0.001) and compared to the MS patients with relapse (P = 0.010). In NMO patients, the levels of IFN-α were significantly associated with EDSS (P = 0.0062). It may be concluded that IFN-α was detectable in a subgroup of NMO patients. Association of IFN-α levels with clinical disease activity and severity suggests a role for IFN-α in disease perpetuation and may provide a plausible explanation for a negative effect of IFN-1 treatment in NMO patients.

IL-32-PAR2 axis is an innate immunity sensor providing alternative signaling for LPS-TRIF axis

Interleukin (IL)-32 is known to exert adujvant effects on innate immune response, however, receptors and downstream signaling pathways remain to be clarified. Here we found that IL-32γ upregulated serine protease activity of proteinase-3 (PR3), in turn triggering protease-activated receptor 2 (PAR2) signaling. Interestingly, silencing of PR3 or PAR2 using siRNA markedly diminished IL-32γ-induced TNFα and IFN-β mRNA expression. IL-32γ-PAR2 axis utilized TRIF and Ras-Raf-1 pathways. On stimulation with lipopolysaccharide (LPS), differential activation of protein kinase C isoforms modulated the balance between LPS-TLR4-TRIF and IL-32-PAR2-TRIF axes, because LPS was a strong inducer of IL-32γ. IL-32-PAR2-TRIF axis might serve not only as an extracellular sensor of bacterial and autologous proteases, but also as a modulator of innate and adaptive immunity during infection.

Pathogen signatures activate a ubiquitination pathway that modulates the function of the metabolic checkpoint kinase mTOR

The mammalian immune system has the ability to discriminate between pathogenic and non-pathogenic microbes to control inflammation. Here we investigated ubiquitinylation profiles of host proteins after infection of macrophages with a virulent strain of the intracellular bacterium Legionella pneumophila and a non-pathogenic mutant. Only infection with pathogenic Legionella resulted in ubiquitinylation of positive regulators of the metabolic checkpoint kinase mTOR leading to diminished mTOR activity. Detection of pathogen signatures resulted in translational biasing to proinflammatory cytokines through mTOR-mediated regulation of cap-dependent translation. Thus, there is a pathogen detection program in macrophages that stimulates protein ubiquitinylation and degradation of mTOR regulators, which suppresses mTOR function and directs a proinflammatory cytokine program.

Type I interferons: beneficial in Th1 and detrimental in Th17 autoimmunity

In relapsing remitting multiple sclerosis (RRMS), type I interferon (IFN) is considered immuno-modulatory, and recombinant forms of IFN-β are the most prescribed treatment for this disease. However, within the RRMS population, 30-50% of MS patients are nonresponsive to this treatment, and it consistently worsens neuromyelitis optica (NMO), a disease once considered to be a form of RRMS. In contrast to RRMS, type I IFNs have been shown to have properties that drive the inflammatory pathologies in many other autoimmune diseases. These diseases include Sjögren's syndrome, system lupus erythematosus (SLE), neuromyelitis optica (NMO), rheumatoid arthritis (RA) and psoriasis. Historically, autoimmune diseases were thought to be driven by a TH1 response to auto-antigens. However, since the discovery of the TH17 in experimental autoimmune encephalomyelitis (EAE), it is now generally thought that TH17 plays an important role in MS and all other autoimmune diseases. In this article, we will discuss recent clinical and basic research advances in the field of autoimmunity and argue that IFN-β and other type I IFNs are immuno-modulatory in diseases driven predominantly by TH1 but in contrast are inflammatory in diseases that have a predominant Th17 response.

The sst1 resistance locus regulates evasion of type I interferon signaling by Chlamydia pneumoniae as a disease tolerance mechanism

The sst1, “supersusceptibility to tuberculosis,” locus has previously been shown to be a genetic determinant of host resistance to infection with the intracellular pathogen, Mycobacterium tuberculosis. Chlamydia pneumoniae is an obligate intracellular bacterium associated with community acquired pneumonia, and chronic infection with C. pneumoniae has been linked to asthma and atherosclerosis. C. pneumoniae is a highly adapted pathogen that can productively infect macrophages and inhibit host cell apoptosis. Here we examined the role of sst1 in regulating the host response to infection with C. pneumoniae. Although mice carrying the sst1 susceptible (sst1^S) locus were not impaired in their ability to clear the acute infection, they were dramatically less tolerant of the induced immune response, displaying higher clinical scores, more severe lung inflammation, exaggerated macrophage and neutrophil influx, and the development of fibrosis compared to wild type mice. This correlated with increased activated caspase-3 in the lungs of infected sst1^S mice. Infection of sst1^S macrophages with C. pneumoniae resulted in a shift in the secreted cytokine profile towards enhanced production of interferon-β and interleukin-10, and induced apoptotic cell death, which was dependent on secretion of interferon-β. Intriguingly macrophages from the sst1^S mice failed to support normal chlamydial growth, resulting in arrested development and failure of the organism to complete its infectious cycle. We conclude that the sst1 locus regulates a shared macrophage-mediated innate defense mechanism against diverse intracellular bacterial pathogens. Its susceptibility allele leads to upregulation of type I interferon pathway, which, in the context of C. pneumoniae, results in decreased tolerance, but not resistance, to the infection. Further dissection of the relationship between type I interferons and host tolerance during infection with intracellular pathogens may provide identification of biomarkers and novel therapeutic targets.

Chlamydia pneumoniae is a highly adapted intracellular pathogen and a common cause of atypical, community acquired pneumonia. It has also been suggested as a trigger or promoter of asthma and atherosclerosis. In this study, we examined the role of a genetic locus on mouse chromosome 1 that has been associated with susceptibility to another intracellular pathogen, Mycobacterium tuberculosis, in the pathogenesis of respiratory infections secondary to Chlamydia pneumoniae. We have determined that a variant at this locus, known as sst1 and associated with destructive pulmonary tuberculosis, makes mice dramatically more sensitive in vivo to the inflammatory changes following respiratory infection with C. pneumoniae. This appears to arise from activation of type I interferons and apoptotic cell death, two signaling pathways that are normally silent during productive C. pneumoniae infection. Despite a noted inability of sst1 susceptible macrophages to support chlamydial development, exuberant lung tissue damage resulted in overall more severe disease in vivo. We conclude the sst1-mediated control of lung tissue damage is an important determinant of the genetic susceptibility of a given host to a number of diverse intracellular bacterial pathogens, which may provide predictors of outcomes to infectious diseases as well as possible target for novel therapeutics.

Involvement of microRNA in microglia-mediated immune response

MicroRNAs (miRNAs) are an abundant class of small noncoding RNA molecules that play an important role in the regulation of gene expression at the posttranscriptional level. Due to their ability to simultaneously modulate the fate of different genes, these molecules are particularly well suited to act as key regulators during immune cell differentiation and activation, and their dysfunction can contribute to pathological conditions associated with neuroinflammation. Recent studies have addressed the role of miRNAs in the differentiation of progenitor cells into microglia and in the activation process, aiming at clarifying the origin of adult microglia cells and the contribution of the central nervous system (CNS) environment to microglia phenotype, in health and disease. Altered expression of several miRNAs has been associated with Alzheimer's disease, multiple sclerosis, and ischemic injury, hence strongly advocating the use of these small molecules as disease markers and new therapeutic targets. This review summarizes the recent advances in the field of miRNA-mediated regulation of microglia development and activation. We discuss the role of specific miRNAs in the maintenance and switching of microglia activation states and illustrate the potential of this class of nucleic acids both as biomarkers of inflammation and new therapeutic tools for the modulation of microglia behavior in the CNS.

Neuromyelitis optica-like pathology is dependent on type I interferon response

Neuromyelitis optica is an antibody-mediated autoimmune inflammatory disease of the central nervous system. Reports have suggested that interferon beta which is beneficial for multiple sclerosis, exacerbates neuromyelitis optica. Our aim was to determine whether type I interferon plays a role in the formation of neuromyelitis optica lesions. Immunoglobulin G from a neuromyelitis optica patient was injected intracerebrally with human complement to type I interferon receptor deficient and wildtype mice. Loss of aquaporin-4 and glial fibrillary acidic protein was reduced in type I interferon receptor deficient mice brain. Our findings suggest that type I interferon signaling contributes to neuromyelitis optica pathogenesis.