Synergy of IL-27 and TNF-α in regulating CXCL10 expression in lung fibroblasts

Study on Potential Differentially Expressed Genes in Idiopathic Pulmonary Fibrosis by Bioinformatics and Next-Generation Sequencing Data Analysis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease with reduced quality of life and earlier mortality, but its pathogenesis and key genes are still unclear. In this investigation, bioinformatics was used to deeply analyze the pathogenesis of IPF and related key genes, so as to investigate the potential molecular pathogenesis of IPF and provide guidance for clinical treatment. Next-generation sequencing dataset GSE213001 was obtained from Gene Expression Omnibus (GEO), and the differentially expressed genes (DEGs) were identified between IPF and normal control group. The DEGs between IPF and normal control group were screened with the DESeq2 package of R language. The Gene Ontology (GO) and REACTOME pathway enrichment analyses of the DEGs were performed. Using the g:Profiler, the function and pathway enrichment analyses of DEGs were performed. Then, a protein-protein interaction (PPI) network was constructed via the Integrated Interactions Database (IID) database. Cytoscape with Network Analyzer was used to identify the hub genes. miRNet and NetworkAnalyst databaseswereused to construct the targeted microRNAs (miRNAs), transcription factors (TFs), and small drug molecules. Finally, receiver operating characteristic (ROC) curve analysis was used to validate the hub genes. A total of 958 DEGs were screened out in this study, including 479 up regulated genes and 479 down regulated genes. Most of the DEGs were significantly enriched in response to stimulus, GPCR ligand binding, microtubule-based process, and defective GALNT3 causes HFTC. In combination with the results of the PPI network, miRNA-hub gene regulatory network and TF-hub gene regulatory network, hub genes including LRRK2, BMI1, EBP, MNDA, KBTBD7, KRT15, OTX1, TEKT4, SPAG8, and EFHC2 were selected. Cyclothiazide and rotigotinethe are predicted small drug molecules for IPF treatment. Our findings will contribute to identification of potential biomarkers and novel strategies for the treatment of IPF, and provide a novel strategy for clinical therapy.

p38 MAPK signaling in chronic obstructive pulmonary disease pathogenesis and inhibitor therapeutics

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar remodeling. Although the abnormalities are primarily prompted by chronic exposure to inhaled irritants, maladjusted and self-reinforcing immune responses are significant contributors to the development and progression of the disease. The p38 isoforms are regarded as pivotal hub proteins that regulate immune and inflammatory responses in both healthy and disease states. As a result, their inhibition has been the subject of numerous recent studies exploring their therapeutic potential in COPD.

MAIN BODY

We performed a systematic search based on the PRISMA guidelines to find relevant studies about P38 signaling in COPD patients. We searched the PubMed and Google Scholar databases and used "P38" AND "COPD" Mesh Terms. We applied the following inclusion criteria: (1) human, animal, ex vivo and in vitro studies; (2) original research articles; (3) published in English; and (4) focused on P38 signaling in COPD pathogenesis, progression, or treatment. We screened the titles and abstracts of the retrieved studies and assessed the full texts of the eligible studies for quality and relevance. We extracted the following data from each study: authors, year, country, sample size, study design, cell type, intervention, outcome, and main findings. We classified the studies according to the role of different cells and treatments in P38 signaling in COPD.

CONCLUSION

While targeting p38 MAPK has demonstrated some therapeutic potential in COPD, its efficacy is limited. Nevertheless, combining p38 MAPK inhibitors with other anti-inflammatory steroids appears to be a promising treatment choice. Clinical trials testing various p38 MAPK inhibitors have produced mixed results, with some showing improvement in lung function and reduction in exacerbations in COPD patients. Despite these mixed results, research on p38 MAPK inhibitors is still a major area of study to develop new and more effective therapies for COPD. As our understanding of COPD evolves, we may gain a better understanding of how to utilize p38 MAPK inhibitors to treat this disease. Video Abstract.

IL-27 induces LL-37/CRAMP expression from intestinal epithelial cells: implications for immunotherapy of Clostridioides difficile infection

Clostridioides difficile infection is currently the leading cause of nosocomial antibiotic-associated diarrhea and pseudomembranous colitis worldwide. Cathelicidins, a major group of natural antimicrobial peptides, have antimicrobial and immunomodulatory activities in Clostridioides difficile infection. Here, we have shown that cytokine IL-27 induced human cathelicidin antimicrobial peptide (LL-37) expression in primary human colonic epithelial cells. IL-27 receptor-deficient mice had impaired expression of cathelicidin-related antimicrobial peptide (CRAMP, mouse homolog for human LL-37) after Clostridioides difficile infection, and restoration of CRAMP improved Clostridium difficile clearance and reduced mortality in IL-27 receptor-deficient mice after Clostridioides difficile challenge. In clinical samples from 119 patients with Clostridioides difficile infection, elevated levels of IL-27 were positively correlated with LL-37 in the sera and stools. These findings suggest that IL-27 may be involved in host immunity against Clostridioides difficile infection via induction of LL-37/CRAMP. Therefore, IL-27-LL-37 axis may be a valuable pathway in the development of immune-based therapy.

T cells drive negative feedback mechanisms in cancer associated fibroblasts, promoting expression of co-inhibitory ligands, CD73 and IL-27 in non-small cell lung cancer

The success of immune checkpoint therapy shows tumor-reactive T cells can eliminate cancer cells but are restrained by immunosuppression within the tumor micro-environment (TME). Cancer associated fibroblasts (CAFs) are the dominant stromal cell in the TME and co-localize with T cells in non-small cell lung cancer. We demonstrate the bidirectional nature of CAF/T cell interactions; T cells promote expression of co-inhibitory ligands, MHC molecules and CD73 on CAFs, increasing their production of IL-6 and eliciting production of IL-27. In turn CAFs upregulate co-inhibitory receptors on T cells including the ectonucleotidase CD39 promoting development of an exhausted but highly cytotoxic phenotype. Our results highlight the bidirectional interaction between T cells and CAFs in promoting components of the immunosuppressive CD39, CD73 adenosine pathway and demonstrate IL-27 production can be induced in CAF by activated T cells.

TNF-α augments CXCL10/CXCR3 axis activity to induce Epithelial-Mesenchymal Transition in colon cancer cell

Chronic inflammation-induced metastases have long been regarded as one of the significant obstacles in treating cancer. Tumor necrosis factor-α (TNF-α), a main inflammation mediator within tumor microenvironment, affects tumor development by inducing multiple chemokines to establish a complex network. Recent reports have revealed that CXCL10/CXCR3 axis affects cancer cells invasiveness and metastases, and Epithelial-mesenchymal transition (EMT) is the main reason for frequent proliferation and distant organ metastases of colon cancer (CC) cells, However, it is unclear whether TNF-α- mediated chronic inflammation can synergically enhance EMT-mediated CC metastasis through promoting chemokine expression. According to this study, TNF-α activated the PI3K/Akt and p38 MAPK parallel signal transduction pathways, then stimulate downstream NF-κB pathway p65 into the nucleus to activate CXCL10 transcription. CXCL10 enhanced the metastases of CC-cells by triggering small GTPases such as RhoA and cdc42. Furthermore, overexpression of CXCL10 significantly enhanced tumorigenicity and mobility of CC cells in vivo. We further clarified that CXCL10 activated the PI3K/Akt pathway through CXCR3, resulting in suppression of GSK-3β phosphorylation and leading to upregulation of Snail expression, thereby regulating EMT in CC cells. These outcomes lay the foundation for finding new targets to inhibit CC metastases.

EGR3-HDAC6-IL-27 Axis Mediates Allergic Inflammation and Is Necessary for Tumorigenic Potential of Cancer Cells Enhanced by Allergic Inflammation-Promoted Cellular Interactions

The objective of this study was to investigate mechanisms of allergic inflammation both in vitro and in vivo in details. For this, RNA sequencing was performed. Early growth response 3 gene (Egr3) was one of the most highly upregulated genes in rat basophilic leukemia (RBL2H3) cells stimulated by antigen. The role of Egr3 in allergic inflammation has not been studied extensively. Egr3 was necessary for passive cutaneous anaphylaxis (PCA) and passive systemic anaphylaxis (PSA). Egr3 promoter sequences contained potential binding site for NF-κB p65. NF-κB p65 directly regulated Egr3 expression and mediated allergic inflammation in vitro. Histone deacetylases (HDACs) is known to be involved in allergic airway inflammation. HDAC6 promoter sequences contained potential binding site for EGR3. EGR3 showed binding to promoter sequences of HDAC6. EGR3 was necessary for increased expression of histone deacetylase 6 (HDAC6) in antigen-stimulated RBL2H3 cells. HDAC6 mediated allergic inflammation in vitro and PSA. TargetScan analysis predicted that miR-182-5p was a negative regulator of EGR3. Luciferase activity assay confirmed that miR-182-5p was a direct regulator of EGR3. MiR-182-5p mimic inhibited allergic inflammation both in vitro and in vivo. Cytokine array showed that HDAC6 was necessary for increased interleukin-27 (IL-27) expression in BALB/C mouse model of PSA. Antigen stimulation did not affect expression of EBI3, another subunit of IL-27 in RBL2H3 cells or BALB/C mouse model of PCA or PSA. IL-27 receptor alpha was shown to be able to bind to HDAC6. IL-27 p28 mediated allergic inflammation in vitro, PCA, and PSA. Mouse recombinant IL-27 protein promoted features of allergic inflammation in an antigen-independent manner. HDAC6 was necessary for tumorigenic and metastatic potential enhanced by PSA. PSA enhanced the metastatic potential of mouse melanoma B16F1 cells in an IL-27-dependent manner. Experiments employing culture medium and mouse recombinant IL-27 protein showed that IL-27 mediated and promoted cellular interactions involving B16F1 cells, lung macrophages, and mast cells during allergic inflammation. IL-27 was present in exosomes of antigen-stimulated RBL2H3 cells. Exosomes from antigen-stimulated RBL2H3 cells enhanced invasion of B16F1 melanoma cells in an IL-27-dependemt manner. These results present evidence that EGR3-HDAC6-IL-27 axis can regulate allergic inflammation by mediating cellular interactions.

Toll-Like Receptor 2-Tpl2-Dependent ERK Signaling Drives Inverse Interleukin 12 Regulation in Dendritic Cells and Macrophages

This study investigated responses to Toll-like receptor 2 (TLR2)-driven extracellular signal-related kinase (ERK) signaling in dendritic cells (DCs) versus macrophages. TLR2 signaling was induced with Pam₃Cys-Ser-Lys₄, and the role of ERK signaling was interrogated pharmacologically with MEK1/2 inhibitor U0126 or genetically with bone marrow-derived macrophages or DCs from Tpl2^-/- mice. We assessed cytokine production via enzyme-linked immunosorbent assay (ELISA) or V-Plex, and mRNA levels were assessed via reverse transcriptase quantitative PCR (qRT-PCR). In macrophages, blockade of ERK signaling by pharmacologic or genetic approaches inhibited interleukin 10 (IL-10) expression and increased expression of the p40 subunit shared by IL-12 and IL-23 (IL-12/23p40). In DCs, blockade of ERK signaling similarly inhibited IL-10 expression but decreased IL-12/23p40 expression, which is opposite to the effect of ERK signaling blockade on IL-12/23p40 in macrophages. This difference in IL-12/23p40 regulation correlated with the differential expression of transcription factors cFos and IRF1, which are known to regulate IL-12 family members, including IL-12 and IL-23. Thus, the impact of ERK signaling in response to TLR2 stimulation differs between macrophages and DCs, potentially regulating their distinctive functions in the immune system. ERK-mediated suppression of IL-12/23p40 in macrophages may prevent excessive inflammation and associated tissue damage following TLR2-stimulation, while ERK-mediated induction of IL-12/23p40 in DCs may promote priming of T helper 1 (Th1) responses. A greater understanding of the role that ERK signaling plays in different immune cell types may inform the development of host-directed therapy and optimal adjuvanticity for a number of infectious pathogens.

IL-32 induces epithelial-mesenchymal transition by triggering endoplasmic reticulum stress in A549 cells

Background

Epithelial-mesenchymal transition (EMT) is a key process in the onset and development of idiopathic pulmonary fibrosis (IPF) with unclear mechanisms. Our previous studies found that bleomycin and tunicamycin could induce ER stress and consequently trigger EMT accompanying with IL-32 overexpression. This study was aimed to investigate the effects of IL-32 on EMT and ER stress to elucidate the pathogenesis of IPF.

Methods

Human lung adenocarcinoma A549 cells were treated with recombinant human (rh)IL-32, IL-32 siRNA and EMT inducer tunicamycin, or 4-phenylbutyric acid (4-PBA), respectively. Then the cell morphology was observed and the expression of ER-related markers and EMT-related markers were detected by RT-qPCR or western blotting.

Results

Stimulation of A549 cells with rhIL-32 led to a morphological change from a pebble-like shape to an elongated shape in a portion of the cells, accompanied by down regulated expression of the epithelial cell marker E-cadherin and up regulated expression of the mesenchymal cell markers N-cadherin, Vimentin, and Zeb-1. However, these rhIL-32 induced changes were inhibited by the ER stress inhibitor 4-PBA. Suppression of IL-32 expression with siRNA inhibited TM-induced EMT. Further stimulation of the A549 cells with rhIL-32 demonstrated an increase in the expression of GRP78, although this increase was also inhibited by 4-PBA.

Conclusions

These results suggest that IL-32 induces EMT in A549 cells by triggering ER stress, and IL-32 may be a novel marker for IPF.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12890-020-01319-z.

Innate Immune Responses to Highly Pathogenic Coronaviruses and Other Significant Respiratory Viral Infections

The new pandemic virus SARS-CoV-2 emerged in China and spread around the world in <3 months, infecting millions of people, and causing countries to shut down public life and businesses. Nearly all nations were unprepared for this pandemic with healthcare systems stretched to their limits due to the lack of an effective vaccine and treatment. Infection with SARS-CoV-2 can lead to Coronavirus disease 2019 (COVID-19). COVID-19 is respiratory disease that can result in a cytokine storm with stark differences in morbidity and mortality between younger and older patient populations. Details regarding mechanisms of viral entry via the respiratory system and immune system correlates of protection or pathogenesis have not been fully elucidated. Here, we provide an overview of the innate immune responses in the lung to the coronaviruses MERS-CoV, SARS-CoV, and SARS-CoV-2. This review provides insight into key innate immune mechanisms that will aid in the development of therapeutics and preventive vaccines for SARS-CoV-2 infection.

Characterization of cytokine profile to distinguish latent tuberculosis from active tuberculosis and healthy controls

BACKGROUND

Tuberculosis (TB) is an infectious disease and its mortality rate ranks first. Latent tuberculosis infection (LTBI) means that a patient is infected with Mycobacterium tuberculosis, but has no relative clinical symptoms. It has been estimated that approximately 10% of patients with LTBI would develop into active tuberculosis. Therefore, it was urgent to search for more efficient biomarkers to discriminate LTBI from healthy population.

METHODS

The Luminex assay was employed to detect the quantity of cytokines secreted by mononuclear cells from peripheral blood stimulated with the ESAT6 protein among TB, LTBI and healthy controls. The cytokine profile was analyzed by principal components analysis and the receiver operating characteristic curve analysis.

RESULTS

The principal components analysis indicated that LTBI and TB were clearly separated from healthy controls, and that LTBI was also successfully differentiated from healthy controls. The cytokine profiling method to distinguish LTBI from healthy controls has a sensitivity and specificity of 100%. Nine potential biomarkers, including IL-23, IL-21, HGF, Bngf, IL-27, IL-31, IL-1β, IL-22 and IL-18, were identified, and these cytokines were considered as a potential cytokine complex for more effectively discriminating LTBI from healthy controls.

CONCLUSION

IL-23, IL-21, HGF, Bngf, IL-27, IL-31, IL-1β, IL-22 and IL-18 were demonstrated to be the potential cytokine complex for the assessment between LTBI and healthy controls.

IL-27 regulation of innate immunity and control of microbial growth

IL-27 is a pleiotropic cytokine capable of influencing both innate and adaptive immune responses. With anti- and pro-inflammatory activity, IL-27 exerts its opposing effects in a cell-dependent and infectious context-specific manner. Upon pathogenic stimuli, IL-27 regulates innate immune cells, such as monocytes, dendritic cells, macrophages and neutrophils. Immune responses involving these innate cells that are negatively regulated by IL-27 signaling include inflammatory cytokine production, phagolysosomal acidification following phagocytosis, oxidative burst and autophagy. IL-27 signaling is crucial in maintaining the subtle balance between Th1 and Th2 immunity, in which protective inflammation is upregulated within the early stages of infection and subsequently downregulated once microbial growth is controlled. The immunomodulatory effects of IL-27 provide promising therapeutic targets for multiple disease types.

A primary role of IL-27 is to communicate between various immune cells to initiate different immune responses. Among these responses are those involved with destroying and eliminating microbial pathogens and then turning off inflammatory responses when the infectious threat has been resolved. IL-27 possesses both anti- and pro-inflammatory activity that varies with context, immune cell and pathogen stimulus. Depending on the precise formula of these details, there are important implications for IL-27 in disease outcomes. As such, harnessing or opposing IL-27 activity may have the potential to treat a variety of infectious diseases.

Exploration of the Serum Interleukin-17 and Interleukin-27 Expression Levels in Children with Bronchial Asthma and Their Correlation with Indicators of Lung Function

Aims: To investigate the expression levels of serum interleukin-17 (IL-17) and interleukin-27 (IL-27) in children with bronchial asthma and to correlate these expression levels with lung function indicators. Methods: A total of 106 children with bronchial asthma (observation group: 76 in the acute attack phase, 30 in remission) and 60 healthy children (control group) aged 1-10 years were enrolled. Results: Levels of IL-17, IL-27, and fractional exhaled nitric oxide (FeNO) in the peripheral blood of children with bronchial asthma were higher compared to the control group. In addition, blood IL-17, IL-27, and FeNO levels in the children in the acute stage of bronchial asthma were higher compared with those in remission. The respiratory rate of children in the remission stage was lower compared with those in the acute stage, however, the other indicators were higher. IL-17, IL-27, and FeNO levels positively correlated with the respiratory rate and were negatively correlated with inspiratory time, expiratory time, peak time, and time to reach peak tidal expiratory flow/total expiratory time (TPTEF/TE; all p < 0.05). Conclusion: IL-17 and IL-27 levels are associated with the incidence and the development of bronchial asthma in children, and could be useful diagnostic markers. They may also effectively improve the specificity of FeNO for diagnosing the extent of lung injury in children.

Effect of Vitamin D3 on Lung Damage Induced by Cigarette Smoke in Mice

Cigarette smoking is known to induce serious lung diseases, but there is not an effective method to solve this problem. The present study investigated vitamin D3 on over-expression of CXCR3 and CXCL10 in mice induced by cigarette smoking. A pulmonary airway model was designed, and morphological assessment of emphysema, IL-4, IFN-γ and CXCL10 concentration in bronchoalveolar lavage fluids, expression of CXCR3 and CXCL10 were detected. Emphysema of the mice only exposed to cigarette smoke was significant, and concentration of IL-4, IFN-γ and CXCL10 was also increased. In addition, CXCR3 and CXCL10 were over-expressed. The degree of emphysema, concentration of IL-4, IFN-γ and CXCL10, and expression of CXCR3 and CXCL10 in mice administrated with low dose vitamin D3 were similar to the normally treated mice. Low dose of vitamin D3 can effectively protect the lung from the damage induced by cigarette smoke.

IL-27, IL-30, and IL-35: A Cytokine Triumvirate in Cancer

The role of the immune system in anti-tumor immunity cannot be overstated, as it holds the potential to promote tumor eradication or prevent tumor cell escape. Cytokines are critical to influencing the immune responses and interactions with non-immune cells. Recently, the IL-12 and IL-6 family of cytokines have accumulated newly defined members each with specific immune functions related to various cancers and tumorigenesis. There is a need to better understand how cytokines like IL-27, IL-30, and IL-35 interact with one another, and how a developing tumor can exploit these interactions to enhance immune suppression. Current cytokine-based immunotherapies are associated with cytotoxic side effects which limits the success of treatment. In addition to this toxicity, understanding the complex interactions between immune and cancer cells may be one of the greatest challenges to developing a successful immunotherapy. In this review, we bring forth IL-27, IL-30, and IL-35, “sister cytokines,” along with more recent additions to the IL-12 family, which serve distinct purposes despite sharing structural similarities. We highlight how these cytokines function in the tumor microenvironment by examining their direct effects on cancer cells as well their indirect actions via regulatory functions of immune cells that act to either instigate or inhibit tumor progression. Understanding the context dependent immunomodulatory outcomes of these sister cytokines, as well as their regulation within the tumor microenvironment, may shed light onto novel cancer therapeutic treatments or targets.

Coordination of Immune-Stroma Crosstalk by IL-6 Family Cytokines

Stromal cells are a subject of rapidly growing immunological interest based on their ability to influence virtually all aspects of innate and adaptive immunity. Present in every bodily tissue, stromal cells complement the functions of classical immune cells by sensing pathogens and tissue damage, coordinating leukocyte recruitment and function, and promoting immune response resolution and tissue repair. These diverse roles come with a price: like classical immune cells, inappropriate stromal cell behavior can lead to various forms of pathology, including inflammatory disease, tissue fibrosis, and cancer. An important immunological function of stromal cells is to act as information relays, responding to leukocyte-derived signals and instructing leukocyte behavior in kind. In this regard, several members of the interleukin-6 (IL-6) cytokine family, including IL-6, IL-11, oncostatin M (OSM), and leukemia inhibitory factor (LIF), have gained recognition as factors that mediate crosstalk between stromal and immune cells, with diverse roles in numerous inflammatory and homeostatic processes. This review summarizes our current understanding of how IL-6 family cytokines control stromal-immune crosstalk in health and disease, and how these interactions can be leveraged for clinical benefit.

IL-34 regulates IL-6 and IL-8 production in human lung fibroblasts via MAPK, PI3K-Akt, JAK and NF-κB signaling pathways

IL-34 plays diverse roles in disease due to its inflammatory and immunosuppressive properties. Elevated IL-34 expression has been observed in lung cancers and pulmonary infections although its role is unclear. We found that IL-34 addition to primary lung fibroblasts significantly promoted IL-6 and IL-8 expression in a dose and time dependent manner. These effects were reversed when JAK, NF-κB, Akt and p38 inhibitors were included before IL-34 addition. Protein phosphorylation in these pathways was also observed through western-blotting. Stimulation of human lung fibroblasts with IL-34 in combination with TNF-α, IL-17A and IL-4 enhanced inflammatory cytokine production. Our data confirmed the inflammatory effect of IL-34 on human lung fibroblasts and suggested that the IL-34/CSF-1R axis may be a novel therapeutic target in pulmonary disease.

Effects of fluconazole on the clinical outcome and immune response in fungal co-infected tuberculosis patients

With overuse of the broad-spectrum antibiotics, the pulmonary fungal infection increasingly becomes the most common complication associated with senile pulmonary tuberculosis (TB) and attracts intensive attentions from clinicians. Here we presented the retrospective analysis of impact of fluconazole treatment on the clinical outcome and immune response in fungal co-infected tuberculosis patients. A randomized, double-blind, placebo-controlled trial of fluconazole (100 mg per day for consecutive weeks) in fungal-positive senile tuberculosis patients was conducted in our hospital. Peripheral eosinophil counts were computed by the automatic hematology analyzer. The secretory inflammatory cytokines interferon (IFN)-γ, tumor necrosis factor (TNF)-α and chemokines chemokine C-X-C motif ligand (CXCL)9, CXCL10, CXCL11 were determined with enzyme-linked immunosorbent assay kits. The peripheral T helper 1 cells (Th1) and regulatory T cells (Treg) population were analyzed by flow cytometry. None of significant difference in respect to baseline TB score was observed between placebo and fluconazole groups. Administration of fluconazole significantly stimulated eosinophils population and secretion of inflammatory cytokines IFN-γ and TNF-α. Simultaneously, the peripheral Th1% and chemokines including CXCL9, CSCL10, CXCL11 were markedly induced in response to fluconazole treatment. Fungal infection significantly affected host immunity during tuberculosis which was effectively reversed by fluconazole treatment.

IL-36 induces cytokine IL-6 and chemokine CXCL8 expression in human lung tissue cells: Implications for pulmonary inflammatory responses

IL-36α, IL-36β and IL-36γ are cytokine members of IL-1 family. Although IL-36 expression was observed in human lung during pulmonary infections, it remains unknown whether IL-36 could act directly on lung tissue cells during pulmonary inflammatory responses. In this study, we showed that IL-36 receptor was expressed in human lung fibroblasts and bronchial epithelial cells. Correspondingly, IL-36α, IL-36β or IL-36γ up-regulated gene expression of cytokine IL-6 and chemokine CXCL8 in human lung fibroblasts and bronchial epithelial cells, and promoted IL-6 and CXCL8 release from human lung fibroblasts and bronchial epithelial cells. The production of IL-6 and CXCL8 in these lung tissues cells induced by IL-36α, IL-36β or IL-36γ was regulated by p38MAPK, ERK or Akt signaling pathways. Taken together, the above results suggest that IL-36-mediated IL-6 and CXCL8 production in human lung fibroblasts and bronchial epithelial cells may be involved in pulmonary inflammation especially caused by bacterial or viral infections.

Neuroendocrine Modulation of IL-27 in Macrophages

Heterodimeric IL-27 (p28/EBV-induced gene 3) is an important member of the IL-6/IL-12 cytokine family. IL-27 is predominantly synthesized by mononuclear phagocytes and exerts immunoregulatory functional activities on lymphocytic and nonlymphocytic cells during infection, autoimmunity or neoplasms. There is a great body of evidence on the bidirectional interplay between the autonomic nervous system and immune responses during inflammatory disorders, but so far IL-27 has not been defined as a part of these multifaceted neuroendocrine networks. In this study, we describe the role of catecholamines (as mediators of the sympathetic nervous system) related to IL-27 production in primary mouse macrophages. Noradrenaline and adrenaline dose-dependently suppressed the release of IL-27p28 in LPS/TLR4-activated macrophages, which was independent of α₁ adrenoceptors. Instead, β₂ adrenoceptor activation was responsible for mediating gene silencing of IL-27p28 and EBV-induced gene 3. The β₂ adrenoceptor agonists formoterol and salbutamol mediated suppression of IL-27p28 production, when triggered by zymosan/TLR2, LPS/TLR4, or R848/TLR7/8 activation, but selectively spared the polyinosinic-polycytidylic acid/TLR3 pathway. Mechanistically, β₂ adrenergic signaling reinforced an autocrine feedback loop of macrophage-derived IL-10 and this synergized with inhibition of the JNK pathway for limiting IL-27p28. The JNK inhibitors SP600125 and AEG3482 strongly decreased intracellular IL-27p28 in F4/80⁺CD11b⁺ macrophages. In endotoxic shock of C57BL/6J mice, pharmacologic activation of β₂ adrenoceptors improved the severity of shock, including hypothermia and decreased circulating IL-27p28. Conversely, IL-27p28 was 2.7-fold increased by removal of the catecholamine-producing adrenal glands prior to endotoxic shock. These data suggest a novel role of the sympathetic neuroendocrine system for the modulation of IL-27-dependent acute inflammation.

IL-27 Limits Type 2 Immunopathology Following Parainfluenza Virus Infection

Respiratory paramyxoviruses are important causes of morbidity and mortality, particularly of infants and the elderly. In humans, a T helper (Th)2-biased immune response to these infections is associated with increased disease severity; however, little is known about the endogenous regulators of these responses that may be manipulated to ameliorate pathology. IL-27, a cytokine that regulates Th2 responses, is produced in the lungs during parainfluenza infection, but its role in disease pathogenesis is unknown. To determine whether IL-27 limits the development of pathogenic Th2 responses during paramyxovirus infection, IL-27-deficient or control mice were infected with the murine parainfluenza virus Sendai virus (SeV). Infected IL-27-deficient mice experienced increased weight loss, more severe lung lesions, and decreased survival compared to controls. IL-27 deficiency led to increased pulmonary eosinophils, alternatively activated macrophages (AAMs), and the emergence of Th2 responses. In control mice, IL-27 induced a population of IFN-γ+/IL-10+ CD4+ T cells that was replaced by IFN-γ+/IL-17+ and IFN-γ+/IL-13+ CD4+ T cells in IL-27-deficient mice. CD4+ T cell depletion in IL-27-deficient mice attenuated weight loss and decreased AAMs. Elimination of STAT6 signaling in IL-27-deficient mice reduced Th2 responses and decreased disease severity. These data indicate that endogenous IL-27 limits pathology during parainfluenza virus infection by regulating the quality of CD4+ T cell responses and therefore may have therapeutic potential in paramyxovirus infections.

Andrographolide Restores Steroid Sensitivity To Block Lipopolysaccharide/IFN-γ-Induced IL-27 and Airway Hyperresponsiveness in Mice

LPS and IFN-γ alone or in combination have been implicated in the development of steroid resistance. Combined LPS/IFN-γ strongly upregulates IL-27 production, which has been linked to steroid-resistant airway hyperresponsiveness (AHR). Andrographolide, a bioactive molecule isolated from the plant Andrographis paniculata, has demonstrated anti-inflammatory and antioxidant properties. The present study investigated whether andrographolide could restore steroid sensitivity to block LPS/IFN-γ-induced IL-27 production and AHR via its antioxidative property. The mouse macrophage cell line Raw 264.7, mouse primary lung monocytes/macrophages, and BALB/c mice were treated with LPS/IFN-γ, in the presence and absence of dexamethasone and/or andrographolide. Levels of IL-27 in vitro and in vivo were examined and mouse AHR was assessed. Dexamethasone alone failed to inhibit LPS/IFN-γ-induced IL-27 production and AHR in mice. Andrographolide significantly restored the suppressive effect of dexamethasone on LPS/IFN-γ-induced IL-27 mRNA and protein levels in the macrophage cell line and primary lung monocytes/macrophages, mouse bronchoalveolar lavage fluid and lung tissues, and AHR in mice. LPS/IFN-γ markedly reduced the nuclear level of histone deacetylase (HDAC)2, an essential epigenetic enzyme that mediates steroid anti-inflammatory action. LPS/IFN-γ also decreased total HDAC activity but increased the total histone acetyltransferase/HDAC activity ratio in mouse lungs. Andrographolide significantly restored nuclear HDAC2 protein levels and total HDAC activity, and it diminished the total histone acetyltransferase/HDAC activity ratio in mouse lungs exposed to LPS/IFN-γ, possibly via suppression of PI3K/Akt/HDAC2 phosphorylation, and upregulation of the antioxidant transcription factor NF erythroid-2-related factor 2 level and DNA binding activity. Our data suggest that andrographolide may have therapeutic value in resensitizing steroid action in respiratory disorders such as asthma.

Role of interleukin-27 in inflammatory bowel disease

Inflammatory bowel disease (IBD), which is characterized by chronic or recurrent relapsing gastrointestinal inflammation, includes ulcerative colitis (UC) and Crohn's disease (CD). The pathogenesis of IBD remains obscure, however, abnormal immune responses are regarded as the major component of IBD pathogenesis. Interleukin-27 (IL-27) is a new member of the IL-12 family, and it is produced by activated antigen-presenting cells and plays an important role in the differentiation and function of different T cell subsets. IL-27 has various immunoregulatory functions and is implicated in the pathogenesis of many infectious and autoimmune diseases. Recent studies have showed that IL-27 is strongly associated with the genesis and development of IBD. Here we provide an overview of the role of IL-27 in the pathogenesis of IBD.

Characterization of the immune response in ganglia after primary simian varicella virus infection

Primary simian varicella virus (SVV) infection in non-human primates causes varicella, after which the virus becomes latent in ganglionic neurons and reactivates to cause zoster. The host response in ganglia during establishment of latency is ill-defined. Ganglia from five African green monkeys (AGMs) obtained at 9, 13, and 20 days post-intratracheal SVV inoculation (dpi) were analyzed by ex vivo flow cytometry, immunohistochemistry, and in situ hybridization. Ganglia at 13 and 20 dpi exhibited mild inflammation. Immune infiltrates consisted mostly of CD8(dim) and CD8(bright) memory T cells, some of which expressed granzyme B, and fewer CD11c(+) and CD68(+) cells. Chemoattractant CXCL10 transcripts were expressed in neurons and infiltrating inflammatory cells but did not co-localize with SVV open reading frame 63 (ORF63) RNA expression. Satellite glial cells expressed increased levels of activation markers CD68 and MHC class II at 13 and 20 dpi compared to those at 9 dpi. Overall, local immune responses emerged as viral DNA load in ganglia declined, suggesting that intra-ganglionic immunity contributes to restricting SVV replication.

Nanoparticle surface charge impacts distribution, uptake and lymph node trafficking by pulmonary antigen-presenting cells

Engineered nanoparticles have the potential to expand the breadth of pulmonary therapeutics, especially as respiratory vaccines. Notably, cationic nanoparticles have been demonstrated to produce superior local immune responses following pulmonary delivery; however, the cellular mechanisms of this increased response remain unknown. To this end, we investigated the cellular response of lung APCs following pulmonary instillation of anionic and cationic charged nanoparticles. While nanoparticles of both surface charges were capable of trafficking to the draining lymph node and were readily internalized by alveolar macrophages, both CD11b and CD103 lung dendritic cell (DC) subtypes preferentially associated with cationic nanoparticles. Instillation of cationic nanoparticles resulted in the upregulation of Ccl2 and Cxc10, which likely contributes to the recruitment of CD11b DCs to the lung. In total, these cellular mechanisms explain the increased efficacy of cationic formulations as a pulmonary vaccine carrier and provide critical benchmarks in the design of pulmonary vaccine nanoparticles.

FROM THE CLINICAL EDITOR

Advance in nanotechnology has allowed the production of precise nanoparticles as vaccines. In this regard, pulmonary delivery has the most potential. In this article, the authors investigated the interaction of nanoparticles with various types of lung antigen presenting cells in an attempt to understand the cellular mechanisms. The findings would further help the future design of much improved vaccines for clinical use.

IL-27 enhances innate immunity of human pulmonary fibroblasts and epithelial cells through upregulation of TLR4 expression

Lung tissue cells play an active role in the pathogenesis of pulmonary inflammatory diseases by releasing a variety of cytokines and chemokines. However, how lung tissue cells respond to microbial stimuli during pulmonary infections remains unclear. In this study, we found that patients with community-acquired pneumonia displayed increased IL-27 levels in bronchoalveolar lavage fluid and serum. We subsequently examined the immunopathological mechanisms for the activation of primary human lung fibroblasts and bronchial epithelial cells by IL-27. We demonstrated that IL-27 priming enhanced LPS-induced production of IL-6 and IL-8 from lung fibroblasts and bronchial epithelia cells via upregulating Toll-like receptor-4 (TLR4) expression. IL-27 upregulated TLR4 expression in lung fibroblasts through activation of Janus-activated kinase (JAK) and Jun NH2-terminal kinase (JNK) signaling pathways, and inhibition of the JAK pathway could partially decrease IL-27-induced TLR4 expression, while inhibition of JNK pathway could completely suppress IL-27-induced TLR4 expression. Our data suggest that IL-27 modulates innate immunity of lung tissue cells through upregulating TLR4 expression during pulmonary infections.

c-Jun N-terminal kinase and Akt signalling pathways regulating tumour necrosis factor-α-induced interleukin-32 expression in human lung fibroblasts: implications in airway inflammation

Airway inflammatory diseases such as chronic obstructive pulmonary disease (COPD) and asthma are associated with elevated expression of interleukin-32 (IL-32), a recently described cytokine that appears to play a critical role in inflammation. However, so far, the regulation of pulmonary IL-32 production has not been fully established. We examined the expression of IL-32 by tumour necrosis factor-α (TNF-α) in primary human lung fibroblasts. Human lung fibroblasts were cultured in the presence or absence of TNF-α and/or other cytokines/Toll-like receptor (TLR) ligands or various signalling molecule inhibitors to analyse the expression of IL-32 by quantitative RT-PCR and ELISA. Next, activation of Akt and c-Jun N-terminal kinase (JNK) signalling pathways was investigated by Western blot. Interleukin-32 mRNA of four spliced isoforms (α, β, γ and δ) was up-regulated upon TNF-α stimulation, which was associated with a significant IL-32 protein release from TNF-α-activated human lung fibroblasts. The combination of interferon-γ and TNF-α induced enhanced IL-32 release in human lung fibroblasts, whereas IL-4, IL-17A, IL-27 and TLR ligands did not alter IL-32 release in human lung fibroblasts either alone, or in combination with TNF-α. Furthermore, the activation of Akt and JNK pathways regulated TNF-α-induced IL-32 expression in human lung fibroblasts, and inhibition of the Akt and JNK pathways was able to suppress the increased release of IL-32 to nearly the basal level. These data suggest that TNF-α may be involved in airway inflammation via the induction of IL-32 by activating Akt and JNK signalling pathways. Therefore, the TNF-α/IL-32 axis may be a potential therapeutic target for airway inflammatory diseases.

IL-27 and type 2 immunity in asthmatic patients: association with severity, CXCL9, and signal transducer and activator of transcription signaling

BACKGROUND

Severe asthma (SA) can involve both innate and type 2 cytokine-associated adaptive immunity. Although IL-27 has been reported to potentiate TH1 responses (including the chemokine CXCL9) and suppress TH2 responses, its function in asthmatic patients is unknown.

OBJECTIVE

We sought to evaluate IL-27 expression in human asthma alone and in combination with type 2 immunity to determine the relationship to disease severity and CXCL9 expression. We also sought to model these interactions in vitro in human bronchial epithelial cells.

METHODS

Bronchoalveolar lavage cells from 87 participants were evaluated for IL-27 mRNA and protein alone and in association with epithelial CCL26 (a marker of type 2 activation) in relation to asthma severity and CXCL9 mRNA. Human bronchial epithelial cells cultured at the air-liquid interface and stimulated with IL-27 (1-100 ng/mL) with or without IL-13 (1 ng/mL) were evaluated for CXCL9 expression by using quantitative real-time PCR and ELISA. Phosphorylated and total signal transducer and activator of transcription (STAT) 1/3 were detected by means of Western blotting. Small interfering RNA knockdown of STAT1 or STAT3 was performed.

RESULTS

Bronchoalveolar lavage cell IL-27 mRNA and protein levels were increased in asthmatic patients. Patients with evidence for type 2 pathway activation had higher IL-27 expression (P = .02). Combined IL-27 and CCL26 expression associated with more SA and higher CXCL9 expression (P = .004 and P = .007 respectively), whereas IL-27 alone was associated with milder disease. In vitro IL-13 augmented IL-27-induced CXCL9 expression, which appeared to be due to augmented STAT1 activation and reduced STAT3 activation.

CONCLUSIONS

IL-27, in combination with a type 2/CCL26 signature, identifies a more SA phenotype, perhaps through combined effects of IL-27 and IL-13 on STAT signaling. Understanding these interactions could lead to new targets for asthma therapy.

Activation of IL-27 signalling promotes development of postinfluenza pneumococcal pneumonia

Postinfluenza pneumococcal pneumonia is a common cause of death in humans. However, the role of IL-27 in the pathogenesis of secondary pneumococcal pneumonia after influenza is unknown. We now report that influenza infection induced pulmonary IL-27 production in a type I IFN-α/β receptor (IFNAR) signalling-dependent manner, which sensitized mice to secondary pneumococcal infection downstream of IFNAR pathway. Mice deficient in IL-27 receptor were resistant to secondary pneumococcal infection and generated more IL-17A-producing γδ T cells but not αβ T cells, thereby leading to enhanced neutrophil response during the early phase of host defence. IL-27 treatment could suppress the development of IL-17A-producing γδ T cells activated by Streptococcus pneumoniae and dendritic cells. This suppressive activity of IL-27 on γδ T cells was dependent on transcription factor STAT1. Finally, neutralization of IL-27 or administration of IL-17A restored the role of γδ T cells in combating secondary pneumococcal infection. Our study defines what we believe to be a novel role of IL-27 in impairing host innate immunity against pneumococcal infection.

Tolerogenic signaling by pulmonary CD1c+ dendritic cells induces regulatory T cells in patients with chronic obstructive pulmonary disease by IL-27/IL-10/inducible costimulator ligand

BACKGROUND

Increased mortality rates in patients with chronic obstructive pulmonary disease (COPD) are largely due to severe infectious exacerbations. Impaired respiratory immunity is linked to the enhanced susceptibility to infections. Dendritic cells (DCs) direct host immune responses toward immunity or tolerance. Pulmonary CD1c(+) DCs elicit robust antiviral immune responses in healthy subjects. Nevertheless, their functional specialization in patients with COPD remains unexplored.

OBJECTIVE

We sought to better understand the mechanisms that suppress respiratory immunity in patients with COPD by examining the immunostimulatory and tolerogenic properties of pulmonary CD1c(+) DCs.

METHODS

We analyzed the expression of costimulatory and tolerogenic molecules by pulmonary CD1c(+) DCs from patients with COPD (CD1c(+)DCCOPD) and former smokers without COPD. We isolated lung CD1c(+) DCs and determined their ability to stimulate allogeneic T-cell responses. The suppressive effects of lung CD1c(+) DCs and CD1c(+) DC-primed T cells on mixed leukocyte reactions were examined. An experimental human model of COPD exacerbation was used to investigate the levels of critical immunosuppressive molecules in vivo.

RESULTS

CD1c(+) DCs from patients with COPD hinder T-cell effector functions and favor the generation of suppressive IL-10-secreting CD4(+) T cells that function through IL-10 and TGF-β. IL-27, IL-10, and inducible T-cell costimulator ligand signaling are essential for CD1c(+)DCCOPD-mediated differentiation of IL-10-producing suppressive T cells. Exposure of lung CD1c(+) DCs from nonobstructed subjects to lungs of patients with COPD confers tolerogenic properties. IL-27 and IL-10 levels are increased in the lung microenvironment on rhinovirus-induced COPD exacerbation in vivo.

CONCLUSION

We identify a novel tolerogenic circuit encompassing suppressive CD1c(+) DCs and regulatory T cells in patients with COPD that might be implicated in impaired respiratory immunity and further highlight IL-10 and IL-27 as potent therapeutic targets.

Regulation of pulmonary inflammation by mesenchymal cells

Pulmonary inflammation and tissue remodelling are common elements of chronic respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and pulmonary hypertension (PH). In disease, pulmonary mesenchymal cells not only contribute to tissue remodelling, but also have an important role in pulmonary inflammation. This review will describe the immunomodulatory functions of pulmonary mesenchymal cells, such as airway smooth muscle (ASM) cells and lung fibroblasts, in chronic respiratory disease. An important theme of the review is that pulmonary mesenchymal cells not only respond to inflammatory mediators, but also produce their own mediators, whether pro-inflammatory or pro-resolving, which influence the quantity and quality of the lung immune response. The notion that defective pro-inflammatory or pro-resolving signalling in these cells potentially contributes to disease progression is also discussed. Finally, the concept of specifically targeting pulmonary mesenchymal cell immunomodulatory function to improve therapeutic control of chronic respiratory disease is considered.

IL-27 activates human trophoblasts to express IP-10 and IL-6: implications in the immunopathophysiology of preeclampsia

Purpose. To investigate the effects of IL-27 on human trophoblasts and the underlying regulatory signaling mechanisms in preeclampsia. Methods. The expression of IL-27 and IL-27 receptor (WSX-1) was studied in the placenta or sera from patients with preeclampsia. In vitro, we investigated the effects of IL-27 alone or in combination with inflammatory cytokine tumor necrosis factor (TNF-α) on the proinflammatory activation of human trophoblast cells (HTR-8/SVneo) and the underlying intracellular signaling molecules. Results. The expression of IL-27 and IL-27 receptor α (WSX-1) was significantly elevated in the trophoblastic cells from the placenta of patients with preeclampsia compared with control specimens. In vitro, IL-27 could induce the expression of inflammatory factors IFN-γ-inducible protein 10 (CXCL10/IP-10) and IL-6 in trophoblasts, and a synergistic effect was observed in the combined treatment of IL-27 and TNF-α on the release of IP-10 and IL-6. Furthermore, the production of IP-10 and IL-6 stimulated by IL-27 was differentially regulated by intracellular activation of phosphatidylinositol 3-OH kinase-AKT, p38MAPK, and JAK/STAT pathways. Conclusions. These results provide a new insight into the IL-27-activated immunopathological effects mediated by distinct intracellular signal transduction molecules in preeclampsia.

Progression of clinical tuberculosis is associated with a Th2 immune response signature in combination with elevated levels of SOCS3

In this study, we explored the local cytokine/chemokine profiles in patients with active pulmonary or pleural tuberculosis (TB) using multiplex protein analysis of bronchoalveolar lavage and pleural fluid samples. Despite increased pro-inflammation compared to the uninfected controls; there was no up-regulation of IFN-γ or the T cell chemoattractant CCL5 in the lung of patients with pulmonary TB. Instead, elevated levels of IL-4 and CCL4 were associated with high mycobacteria-specific IgG titres as well as SOCS3 (suppressors of cytokine signaling) mRNA and progression of moderate-to-severe disease. Contrary, IL-4, CCL4 and SOCS3 remained low in patients with extrapulmonary pleural TB, while IFN-γ, CCL5 and SOCS1 were up-regulated. Both SOCS molecules were induced in human macrophages infected with Mycobacterium tuberculosis in vitro. The Th2 immune response signature found in patients with progressive pulmonary TB could result from inappropriate cytokine/chemokine responses and excessive SOCS3 expression that may represent potential targets for clinical TB management.

Modulation of inflammation by interleukin-27

A growing body of evidence suggests an essential role of the heterodimeric cytokine, IL-27, for regulating immunity. IL-27 is composed of two subunits (p28 and EBI3) and is classified as a member of the IL-12 family of cytokines. APCs have been recognized as a major cellular source of IL-27 following activation with microbial products or IFNs (types I and II). In this review, we describe the current knowledge of the implications of IL-27 during the pathogenesis of infectious and autoimmune diseases. Experimental studies have used genetically targeted IL-27RA-/- mice, EBI3-/- mice, and p28-/- mice or involved study designs with administration of bioengineered IL-27/IL-27RA homologs. Whereas many reports have described that IL-27 suppresses inflammation, we also review the current literature, suggesting promotion of inflammation by IL-27 in some settings. Recent advances have also been made in understanding the cross-talk of cleavage products of the complement system with IL-27-mediated immune responses. Additional data on IL-27 have been obtained recently by observational studies in human patients with acute and chronic inflammatory diseases. Collectively, the findings from the past decade identify IL-27 as a critical immunoregulatory cytokine, especially for T cells, whereas some controversy is fueled by results challenging the view of IL-27 as a classical silencer of inflammation.