Oxidative stress-mediated iNKT-cell activation is involved in COPD pathogenesis

Over-activation of iNKT cells aggravate lung injury in bronchopulmonary dysplasia mice

Bronchopulmonary dysplasia (BPD) is a severe lung disease in preterm infants, the abnormal proliferate and differentiate ability of type II epithelial cells (AEC II) is the key to the pathological basis of BPD. Mechanisms regarding abnormal AEC II in BPD remain unclear. The present work investigated the role and mechanisms of invariant natural killer T (iNKT) cells in lung disorder in BPD using public datasets, clinical samples, a hyperoxia-induced BPD mouse model and AEC II-iNKT cells transwell co-culture system. Firstly, we found that the NKT cells development factor IL-15 increased over time in patients with BPD in public databases, and clinically collected peripheral blood NKT cells in patients with BPD were increased. Subsequently, the percentage of iNKT cells increased in hyperoxia group compared with normoxia group, with the highest at P7, accompanied by increased activation with abnormal lung development. The administration of anti-CD1d neutralizing antibody to inhibit iNKT cells could alleviate the abnormal lung development of hyperoxia group mice, while α-GalCer administration could aggravate lung injury in hyperoxia group mice, and adoptive transfer of iNKT cells could aggravate the abnormal lung development in hyperoxia group mice. In addition, to further verify the role of iNKT cells on AEC II, AEC II-iNKT cells co-culture system was established. The presence of iNKT cells could aggravate the abnormal expression of SP-C and T1α under hyperoxia. Meanwhile, RNA-seq analysis showed that ferroptosis-related genes were highly expressed in AEC II co-cultured with iNKT cells under hyperoxia. We further validated the effect of the presence of iNKT cells under hyperoxia environment on AEC II ferroptosis levels, suggested that iNKT cells promote AEC II ferroptosis under hyperoxia, accompanied by decreased expression of SP-C and T1α. Our study found that the recruitment of iNKT cells in the lung may be an important cause of alveolarization disorder in BPD.

The Role of Exhaled Breath Condensate in Chronic Inflammatory and Neoplastic Diseases of the Respiratory Tract

Asthma and chronic obstructive pulmonary disease (COPD) are among the most common chronic respiratory diseases. Chronic inflammation of the airways leads to an increased production of inflammatory markers by the effector cells of the respiratory tract and lung tissue. These biomarkers allow the assessment of physiological and pathological processes and responses to therapeutic interventions. Lung cancer, which is characterized by high mortality, is one of the most frequently diagnosed cancers worldwide. Current screening methods and tissue biopsies have limitations that highlight the need for rapid diagnosis, patient differentiation, and effective management and monitoring. One promising non-invasive diagnostic method for respiratory diseases is the assessment of exhaled breath condensate (EBC). EBC contains a mixture of volatile and non-volatile biomarkers such as cytokines, leukotrienes, oxidative stress markers, and molecular biomarkers, providing significant information about inflammatory and neoplastic states in the lungs. This article summarizes the research on the application and development of EBC assessment in diagnosing and monitoring respiratory diseases, focusing on asthma, COPD, and lung cancer. The process of collecting condensate, potential issues, and selected groups of markers for detailed disease assessment in the future are discussed. Further research may contribute to the development of more precise and personalized diagnostic and treatment methods.

Immune Dysregulation in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a disease whose incidence increase with age and is characterised by chronic inflammation and significant immune dysregulation. Inhalation of toxic substances cause oxidative stress in the lung tissue as well as airway inflammation, under the recruitment of chemokines, immune cells gathered and are activated to play a defensive role. However, persistent inflammation damages the immune system and leads to immune dysregulation, which is mainly manifested in the reduction of the body's immune response to antigens, and immune cells function are impaired, further destroy the respiratory defensive system, leading to recurrent lower respiratory infections and progressive exacerbation of the disease, thus immune dysregulation play an important role in the pathogenesis of COPD. This review summarizes the changes of innate and adaptive immune-related cells during the pathogenesis of COPD, aiming to control COPD airway inflammation and improve lung tissue remodelling by regulating immune dysregulation, for further reducing the risk of COPD progression and opening new avenues of therapeutic intervention in COPD.

Exposure to urban nanoparticles at low PM[Formula: see text] concentrations as a source of oxidative stress and inflammation

Exposures to fine particulate matter (PM[Formula: see text]) have been associated with health impacts, but the understanding of the PM[Formula: see text] concentration-response (PM[Formula: see text]-CR) relationships, especially at low PM[Formula: see text], remains incomplete. Here, we present novel data using a methodology to mimic lung exposure to ambient air (2[Formula: see text] 60 [Formula: see text]g m[Formula: see text]), with minimized sampling artifacts for nanoparticles. A reference model (Air Liquid Interface cultures of human bronchial epithelial cells, BEAS-2B) was used for aerosol exposure. Non-linearities observed in PM[Formula: see text]-CR curves are interpreted as a result of the interplay between the aerosol total oxidative potential (OP[Formula: see text]) and its distribution across particle size (d[Formula: see text]). A d[Formula: see text]-dependent condensation sink (CS) is assessed together with the distribution with d[Formula: see text] of reactive species . Urban ambient aerosol high in OP[Formula: see text], as indicated by the DTT assay, with (possibly copper-containing) nanoparticles, shows higher pro-inflammatory and oxidative responses, this occurring at lower PM[Formula: see text] concentrations (< 5 [Formula: see text]g m[Formula: see text]). Among the implications of this work, there are recommendations for global efforts to go toward the refinement of actual air quality standards with metrics considering the distribution of OP[Formula: see text] with d[Formula: see text] also at relatively low PM[Formula: see text].

Early innate cell interactions with Mycobacterium tuberculosis in protection and pathology of tuberculosis

Tuberculosis (TB) remains a significant global health challenge, claiming the lives of up to 1.5 million individuals annually. TB is caused by the human pathogen Mycobacterium tuberculosis (Mtb), which primarily infects innate immune cells in the lungs. These immune cells play a critical role in the host defense against Mtb infection, influencing the inflammatory environment in the lungs, and facilitating the development of adaptive immunity. However, Mtb exploits and manipulates innate immune cells, using them as favorable niche for replication. Unfortunately, our understanding of the early interactions between Mtb and innate effector cells remains limited. This review underscores the interactions between Mtb and various innate immune cells, such as macrophages, dendritic cells, granulocytes, NK cells, innate lymphocytes-iNKT and ILCs. In addition, the contribution of alveolar epithelial cell and endothelial cells that constitutes the mucosal barrier in TB immunity will be discussed. Gaining insights into the early cellular basis of immune reactions to Mtb infection is crucial for our understanding of Mtb resistance and disease tolerance mechanisms. We argue that a better understanding of the early host-pathogen interactions could inform on future vaccination approaches and devise intervention strategies.

IL-20 Cytokines Are Involved in the Repair of Airway Epithelial Barrier: Implication in Exposure to Cigarette Smoke and in COPD Pathology

BACKGROUND

Dysregulated inflammation as seen in chronic obstructive pulmonary disease (COPD) is associated with impaired wound healing. IL-20 cytokines are known to be involved in wound healing processes. The purpose of this study was to use ex vivo and in vitro approaches mimicking COPD to evaluate the potential modulatory role of interleukin-20 (IL-20) on the inflammatory and healing responses to epithelial wounding.

METHODS

The expression of IL-20 cytokines and their receptors was investigated in lung-derived samples collected from non-COPD and COPD patients, from mice chronically exposed to cigarette smoke and from airway epithelial cells from humans and mice exposed in vitro to cigarette smoke. To investigate the role of IL-20 cytokines in wound healing, experiments were performed using a blocking anti-IL-20Rb antibody.

RESULTS

Of interest, IL-20 cytokines and their receptors were expressed in bronchial mucosa, especially on airway epithelial cells. Their expression correlated with the disease severity. Blocking these cytokines in a COPD context improved the repair processes after a lesion induced by scratching the epithelial layer.

CONCLUSIONS

Collectively, this study highlights the implication of IL-20 cytokines in the repair of the airway epithelium and in the pathology of COPD. IL-20 subfamily cytokines might provide therapeutic benefit for patients with COPD to improve epithelial healing.

Type 1 invariant natural killer T cells in chronic inflammation and tissue fibrosis

Chronic tissue inflammation often results in fibrosis characterized by the accumulation of extracellular matrix components remodeling normal tissue architecture and function. Recent studies have suggested common immune mechanisms despite the complexity of the interactions between tissue-specific fibroblasts, macrophages, and distinct immune cell populations that mediate fibrosis in various tissues. Natural killer T (NKT) cells recognizing lipid antigens bound to CD1d molecules have been shown to play an important role in chronic inflammation and fibrosis. Here we review recent data in both experimental models and in humans that suggest a key role of type 1 invariant NKT (iNKT) cell activation in the progression of inflammatory cascades leading to recruitment of neutrophils and activation of the inflammasome, macrophages, fibroblasts, and, ultimately, fibrosis. Emerging evidence suggests that iNKT-associated mechanisms contribute to type 1, type 2 and type 3 immune pathways mediating tissue fibrosis, including idiopathic pulmonary fibrosis (IPF). Thus, targeting a pathway upstream of these immune mechanisms, such as the inhibition of iNKT activation, may be important in modulating various fibrotic conditions.

Invariant natural killer T cells in lung diseases

Invariant natural killer T (iNKT) cells are a subset of T cells that are characterized by a restricted T-cell receptor (TCR) repertoire and a unique ability to recognize glycolipid antigens. These cells are found in all tissues, and evidence to date suggests that they play many immunological roles in both homeostasis and inflammatory conditions. The latter include lung inflammatory diseases such as asthma and infections: the roles of lung-resident iNKT cells in these diseases have been extensively researched. Here, we provide insights into the biology of iNKT cells in health and disease, with a particular focus on the role of pulmonary iNKT cells in airway inflammation and other lung diseases.

CD1-mediated immune responses in mucosal tissues: molecular mechanisms underlying lipid antigen presentation system

The cluster of differentiation 1 (CD1) molecule differs from major histocompatibility complex class I and II because it presents glycolipid/lipid antigens. Moreover, the CD1-restricted T cells that recognize these self and foreign antigens participate in both innate and adaptive immune responses. CD1s are constitutively expressed by professional and nonprofessional antigen-presenting cells in mucosal tissues, namely, the skin, lung, and intestine. This suggests that CD1-reactive T cells are involved in the immune responses of these tissues. Indeed, evidence suggests that these cells play important roles in diverse diseases, such as inflammation, autoimmune disease, and infection. Recent studies elucidating the molecular mechanisms by which CD1 presents lipid antigens suggest that defects in these mechanisms could contribute to the activities of CD1-reactive T cells. Thus, improving our understanding of these mechanisms could lead to new and effective therapeutic approaches to CD1-associated diseases. In this review, we discuss the CD1-mediated antigen presentation system and its roles in mucosal tissue immunity.

Mechanisms of lung damage in tuberculosis: implications for chronic obstructive pulmonary disease

Pulmonary tuberculosis is increasingly recognized as a risk factor for COPD. Severe lung function impairment has been reported in post-TB patients. Despite increasing evidence to support the association between TB and COPD, only a few studies describe the immunological basis of COPD among TB patients following successful treatment completion. In this review, we draw on well-elaborated Mycobacterium tuberculosis-induced immune mechanisms in the lungs to highlight shared mechanisms for COPD pathogenesis in the setting of tuberculosis disease. We further examine how such mechanisms could be exploited to guide COPD therapeutics.

IL-20 Cytokines Are Involved in Epithelial Lesions Associated with Virus-Induced COPD Exacerbation in Mice

(1) Background: viral infections are a frequent cause of chronic obstructive pulmonary disease (COPD) exacerbations, which are responsible for disease progression and mortality. Previous reports showed that IL-20 cytokines facilitate bacterial lung infection, but their production and their role in COPD and viral infection has not yet been investigated. (2) Methods: C57BL/6 WT and IL-20 Rb KO mice were chronically exposed to air or cigarette smoke (CS) to mimic COPD. Cytokine production, antiviral response, inflammation and tissue damages were analyzed after PVM infection. (3) Results: CS exposure was associated with an increase in viral burden and antiviral response. PVM infection in CS mice enhanced IFN-γ, inflammation and tissue damage compared to Air mice. PVM infection and CS exposure induced, in an additive manner, IL-20 cytokines expression and the deletion of IL-20 Rb subunit decreased the expression of interferon-stimulated genes and the production of IFN-λ2/3, without an impact on PVM replication. Epithelial cell damages and inflammation were also reduced in IL-20 Rb^-/- mice, and this was associated with reduced lung permeability and the maintenance of intercellular junctions. (4) Conclusions: PVM infection and CS exposure additively upregulates the IL-20 pathway, leading to the promotion of epithelial damages. Our data in our model of viral exacerbation of COPD identify IL-20 cytokine as a potential therapeutic target.

An innate contribution of human nicotinic receptor polymorphisms to COPD-like lesions

Chronic Obstructive Pulmonary Disease is a generally smoking-linked major cause of morbidity and mortality. Genome-wide Association Studies identified a locus including a non-synonymous single nucleotide polymorphism in CHRNA5, rs16969968, encoding the nicotinic acetylcholine receptor α5 subunit, predisposing to both smoking and Chronic Obstructive Pulmonary Disease. Here we report that nasal polyps from rs16969968 non-smoking carriers exhibit airway epithelium remodeling and inflammation. These hallmarks of Chronic Obstructive Pulmonary Disease occur spontaneously in mice expressing human rs16969968. They are significantly amplified after exposure to porcine pancreatic elastase, an emphysema model, and to oxidative stress with a polymorphism-dependent alteration of lung function. Targeted rs16969968 expression in epithelial cells leads to airway remodeling in vivo, increased proliferation and production of pro-inflammatory cytokines through decreased calcium entry and increased adenylyl-cyclase activity. We show that rs16969968 directly contributes to Chronic Obstructive Pulmonary Disease-like lesions, sensitizing the lung to the action of oxidative stress and injury, and represents a therapeutic target.

Human polymorphisms in nicotinic acetylcholine receptor genes have been linked to both smoking and lung diseases like Chronic Obstructive Pulmonary Disease (COPD) or lung cancer. Here the authors identify a direct role for a human coding polymorphism in COPD-like lesions independent of smoke or nicotine exposure.

Epithelium-derived IL17A Promotes Cigarette Smoke-induced Inflammation and Mucus Hyperproduction

Airway epithelium is a central modulator of innate and adaptive immunity in the lung. Interleukin (IL)17A expression was found to be increased in airway epithelium; however, the role of epithelial-derived IL17A in chronic obstructive pulmonary disease (COPD) remains unclear. In this study, we aim to determine whether epithelial-derived IL17A regulates inflammation and mucus hyperproduction in COPD using a cultured human bronchial epithelial (HBE) cell line in vitro and airway epithelium IL17A-specific knockout mouse in vivo. Increased IL17A expression was observed in mouse airway epithelium upon cigarette smoke (CS) exposure or in a COPD mouse model that was induced by CS and elastin. CS extract (CSE) also triggered IL17A expression in HBE cells. Blocking IL17A or IL17RA effectively attenuated CSE-induced MUC5AC and the inflammatory cytokines IL6, tumor necrosis factor (TNF)-α, and IL1β in HBE cells, suggesting that IL17A mediates CSE-induced inflammation and mucin production in an autocrine manner. CSE activated p-JUN and p-JNK, which were also reduced by IL17RA-siRNA, and JUN-siRNA attenuated CSE-induced IL6 and MUC5AC. In vivo, selective knockout of IL17A in airway epithelium markedly reduced the neutrophilic infiltration in Bronchoalveolar Lavage Fluid (BALF), peribronchial inflammation, pro-inflammatory mediators (CXCL1 and CXCL2), and mucus production in a COPD mouse model. We showed a novel function of airway epithelium-derived IL17A, which can act locally in an autocrine manner to amplify inflammation and increase mucus production in COPD pathogenesis.

Impact of domestic mould exposure on Aspergillus biomarkers and lung function in patients with chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) are frequently colonised or sensitised by Aspergillus, but clinical significance remains unclear. Furthermore, little is known on the impact of indoor mould exposure during COPD. In this study, we assessed the relationship between domestic mould exposure, Aspergillus biomarkers and COPD severity during acute exacerbation and at stable state. Aspergillus section Fumigati culture in sputum and anti-Aspergillus antibodies detection (IgG and precipitins) were followed up in COPD patients that were prospectively recruited during exacerbation (n = 62), and underwent a visit at stable state after 18 months (n = 33). Clinical characteristics were collected at inclusion. Electrostatic dust collectors (EDCs) were used to measure domestic mould contamination. Aspergillus section Fumigati was more frequently detected during exacerbation (16.9%) than at stable state (4.0%), but the frequency of patients presenting with anti-Aspergillus antibodies was similar (32.2% and 33.3%, respectively). Aspergillus section Fumigati detection was associated with a higher body-mass index (BMI) during exacerbation, whereas patients with anti-Aspergillus antibodies presented a lower BMI and forced expiratory volume in 1 s, as well as a higher frequency of inhaled corticoids and higher total mould and Penicillium exposure at final visit (P < 0.05). The frequency of patients with anti-Aspergillus antibodies was higher for total mould counts >30 CFU/cm² (P = 0.03). Aspergillosis was diagnosed in 2 patients (6.1%) who presented increased levels of antibodies. Our data suggest that anti-Aspergillus antibodies are associated with chronic lung function alteration and/or domestic mould exposure, thereby supporting the consideration of indoor mould contamination and anti-Aspergillus antibodies kinetics in COPD management.

Mucosal Associated Invariant T Cells Were Activated and Polarized Toward Th17 in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease characterized by airway limitation accompanied with infiltration of inflammatory cells. Mucosal associated invariant T (MAIT) cells can recognize bacteria and play an important role in controlling host immune responses by producing cytokines. In this study, we characterized the function and the ability of MAIT cells to secrete cytokines measured by flow cytometry. In COPD patients, MAIT cells have the ability to produce more IL-17 and less IFN-γ compared to healthy individuals. We found that HLA-DR expression levels reflected the degree of inflammation and the proportion of IL-17 was significantly correlated with lung function in peripheral blood. In addition, we found that MAIT cells were highly expressed in the lung, and the increased expression of CXCR2, CXCL1 indicated that MAIT cells had the potential to migrate to inflammatory tissues. This evidence implies that MAIT cells may play a potential role in COPD immunopathology.

The Toll-Like Receptor 5 agonist flagellin prevents Non-typeable Haemophilus influenzae-induced infection in cigarette smoke-exposed mice

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. The major bacterial cause of COPD exacerbations is non-typeable Haemophilus influenzae (NTHi). 25 to over 80% of cases are associated with NTHi. This susceptibility to infection involves a defective production of interleukin (IL)-22 which plays an important role in mucosal defense. Prophylactic administration of flagellin, a Toll-like receptor 5 (TLR5) agonist, protects healthy mice against respiratory pathogenic bacteria. We hypothesized that TLR5-mediated stimulation of lung immunity might prevent COPD exacerbations. Mice chronically exposed to cigarette smoke (CS), which presented COPD symptoms, were infected with NTHi and intraperitoneally treated with recombinant flagellin following a prophylactic or therapeutic protocol. Compared with control, cigarette smoke-exposed mice treated with flagellin showed a lower bacterial load in the airways, the lungs and the blood. This protection was associated with an early neutrophilia, a lower production of pro-inflammatory cytokines and an increased IL-22 production. Flagellin treatment decreased the recruitment of inflammatory cells and the lung damages related to exacerbation. Morover, the protective effect of flagellin against NTHi was altered by treatment with anti-IL-22 blocking antibodies in cigarette smoke-exposed mice and in Il22-/- mice. The effect of flagellin treatment did not implicated the anti-bacterial peptides calgranulins and defensin-β2. This study shows that stimulation of innate immunity by a TLR5 ligand is a potent antibacterial treatment in CS-exposed mice, suggesting innovative therapeutic strategies against acute exacerbation in COPD.

Senescence in Pulmonary Fibrosis: Between Aging and Exposure

To date, chronic pulmonary pathologies represent the third leading cause of death in the elderly population. Evidence-based projections suggest that >65 (years old) individuals will account for approximately a quarter of the world population before the turn of the century. Genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication, are described as the nine “hallmarks” that govern cellular fitness. Any deviation from the normal pattern initiates a complex cascade of events culminating to a disease state. This blueprint, originally employed to describe aberrant changes in cancer cells, can be also used to describe aging and fibrosis. Pulmonary fibrosis (PF) is the result of a progressive decline in injury resolution processes stemming from endogenous (physiological decline or somatic mutations) or exogenous stress. Environmental, dietary or occupational exposure accelerates the pathogenesis of a senescent phenotype based on (1) window of exposure; (2) dose, duration, recurrence; and (3) cells type being targeted. As the lung ages, the threshold to generate an irreversibly senescent phenotype is lowered. However, we do not have sufficient knowledge to make accurate predictions. In this review, we provide an assessment of the literature that interrogates lung epithelial, mesenchymal, and immune senescence at the intersection of aging, environmental exposure and pulmonary fibrosis.

[Bronchial dilatations in patients with chronic obstructive pulmonary disease in a Tunisian center: effect on disease progression and prognosis]

INTRODUCTION

bronchial dilations (BDs) seem to have a major role in the natural history of chronic obstructive pulmonary disease (COPD). The purpose of our study was to evaluate the impact of BDs on the severity and progression of COPD as well as on patients' prognosis.

METHODS

we conducted a retrospective, single-center, analytical study over the period 1995- 2017. The study was based on data from the medical records of patients with COPD who had undergone chest CT scan during the follow-up period. We compared two groups (G) of patients: G1: COPD with BDs; G2: COPD without BDs.

RESULTS

our study included 466 patients with COPD. Among them 101 (21.6%) had BDs associated with COPD. G1 patients had lower maximum expiratory volume in the first second (FEV1) (G1: 1.21 L, G2: 1.37 L, p = 0.015), lower forced vital capacity (FVC) (p = 0.014), a lower PaO2 at steady state (p = 0.049), a higher rate of acute exacerbations (AE) per year (G1: 3.31, G2: 2.44, p = 0.001) and a higher rate of hospitalizations in the Intensive Care Unit per year (p = 0.02). G1 patients with AE receiving treatment in hospital had lower PaO2 3) on admission (G1: 60 mmHg, G2: 63.7 mmHg, p = 0.02 G2: 63.7 mmHg, p = 0.023), more elevated carbon dioxide (CO2) levels (p = 0.001) and were characterized by a higher use of non-invasive ventilation (NIV) (p = 0.044) and invasive mechanical ventilation (p = 0.011). G2 patients had better overall survival (p = 0.002).

CONCLUSION

bronchial dilatations are an indicator of poor prognosis in patients with chronic obstructive pulmonary disease, expecially because of the higher rate and severity of exacerbations, airway obstructions and mortality.

Boosting the IL-22 response using flagellin prevents bacterial infection in cigarette smoke-exposed mice

The progression of chronic obstructive pulmonary disease (COPD), a lung inflammatory disease being the fourth cause of death worldwide, is marked by acute exacerbations. These episodes are mainly caused by bacterial infections, frequently due to Streptococcus pneumoniae. This susceptibility to infection involves a defect in interleukin (IL)-22, which plays a pivotal role in mucosal defense mechanism. Administration of flagellin, a Toll-like receptor 5 (TLR-5) agonist, can protect mice and primates against respiratory infections in a non-pathological background. We hypothesized that TLR-5-mediated stimulation of innate immunity might improve the development of bacteria-induced exacerbations in a COPD context. Mice chronically exposed to cigarette smoke (CS), mimicking COPD symptoms, are infected with S. pneumoniae, and treated in a preventive and a delayed manner with flagellin. Both treatments induced a lower bacterial load in the lungs and blood, and strongly reduced the inflammation and lung lesions associated with the infection. This protection implicated an enhanced production of IL-22 and involved the recirculation of soluble factors secreted by spleen cells. This is also associated with higher levels of the S100A8 anti-microbial peptide in the lung. Furthermore, human mononuclear cells from non-smokers were able to respond to recombinant flagellin by increasing IL-22 production while active smoker cells do not, a defect associated with an altered IL-23 production. This study shows that stimulation of innate immunity by a TLR-5 ligand reduces CS-induced susceptibility to bacterial infection in mice, and should be considered in therapeutic strategies against COPD exacerbations.

Modelling the Impact of Chronic Cigarette Smoke Exposure in Obese Mice: Metabolic, Pulmonary, Intestinal, and Cardiac Issues

Unhealthy lifestyle choices, such as bad eating behaviors and cigarette smoking, have major detrimental impacts on health. However, the inter-relations between obesity and smoking are still not fully understood. We thus developed an experimental model of high-fat diet-fed obese C57BL/6 male mice chronically exposed to cigarette smoke. Our study evaluated for the first time the resulting effects of the combined exposure to unhealthy diet and cigarette smoke on several metabolic, pulmonary, intestinal, and cardiac parameters. We showed that the chronic exposure to cigarette smoke modified the pattern of body fat distribution in favor of the visceral depots in obese mice, impaired the respiratory function, triggered pulmonary inflammation and emphysema, and was associated with gut microbiota dysbiosis, cardiac hypertrophy and myocardial fibrosis.

MAIT Cells Come to the Rescue in Cancer Immunotherapy?

Recent progress in immunobiology has led to the observation that, among cells classically categorized as the typical representatives of the adaptive immune system, i.e., T cells, some possess the phenotype of innate cells. Invariant T cells are characterized by T cell receptors recognizing a limited range of non-peptide antigens, presented only in the context of particular molecules. Mucosal-associated invariant T cells (MAIT cells) are an example of such unconventional cells. In humans, they constitute between 1% and 8% of the peripheral blood T lymphocytes and are further enriched in mucosal tissues, mesenteric lymph nodes, and liver, where they can account for even 40% of all the T cells. MAIT cells recognize antigens in the context of major histocompatibility complex class I-related protein (MR1). Upon activation, they instantly release pro-inflammatory cytokines and mediate cytolytic function towards bacterially infected cells. As such, they have been a rapidly evolving research topic not only in the field of infectious diseases but also in the context of many chronic inflammatory diseases and, more recently, in immuno-oncology. Novel findings suggest that MAIT cells function could also be modulated by endogenous ligands and drugs, making them an attractive target for therapeutic approaches. In this review, we summarize the current understanding of MAIT cell biology, their role in health and disease and discuss their future potential in cancer immunotherapy. This is discussed through the prism of knowledge and experiences with invariant natural killer T cells (iNKT)—another prominent unconventional T cell subset that shares many features with MAIT cells.

Immune Networks and Therapeutic Targeting of iNKT Cells in Cancer

One of the primary goals in tumor immunotherapy is to reset the immune system from tolerogenic to immunogenic - a process in which invariant natural killer T (iNKT) cells are implicated. iNKT cells develop in the thymus and perform immunosurveillance against tumor cells peripherally. When optimally stimulated, iNKT cells differentiate and display more efficient immune functions. Some cells survive and act as effector memory cells. We discuss the putative roles of iNKT cells in antitumor immunity, and posit that it may be possible to develop novel therapeutic strategies to treat cancers using iNKT cells. In particular, we highlight the challenge of uniquely energizing iNKT cell-licensed dendritic cells to serve as effective immunoadjuvants for both arms of the immune system, thus coupling immunological networks.

Tissue-specific functions of invariant natural killer T cells

Invariant natural killer T cells (iNKT cells) are an innate-like T cell subset that expresses an invariant T cell receptor (TCR) α-chain and recognizes lipids presented on CD1d. They secrete diverse cytokines and can influence many types of immune responses. Despite having highly similar TCR specificities, iNKT cells differentiate in the thymus into distinct subsets that are analogous to T helper 1 (T_H1), T_H2 and T_H17 cell subsets. Additional iNKT cell subsets that may require peripheral activation have also been described, including one that produces IL-10. In general, iNKT cells are non-circulating, tissue-resident lymphocytes, but the prevalence of different iNKT cell subsets differs markedly between tissues. Here, we summarize the functions of iNKT cells in four tissues in which they are prevalent, namely, the liver, the lungs, adipose tissue and the intestine. Importantly, we explain how local iNKT cell responses at each site contribute to tissue homeostasis and protection from infection but can also contribute to tissue inflammation and damage.

The Influence of Innate Lymphoid Cells and Unconventional T Cells in Chronic Inflammatory Lung Disease

The lungs are continuously subjected to environmental insults making them susceptible to infection and injury. They are protected by the respiratory epithelium, which not only serves as a physical barrier but also a reactive one that can release cytokines, chemokines, and other defense proteins in response to danger signals, and can undergo conversion to protective mucus-producing goblet cells. The lungs are also guarded by a complex network of highly specialized immune cells and their mediators to support tissue homeostasis and resolve integrity deviation. This review focuses on specialized innate-like lymphocytes present in the lung that act as key sensors of lung insults and direct the pulmonary immune response. Included amongst these tissue-resident lymphocytes are innate lymphoid cells (ILCs), which are classified into five distinct subsets (natural killer, ILC1, ILC2, ILC3, lymphoid tissue-inducer cells), and unconventional T cells including natural killer T (NKT) cells, mucosal-associated invariant T (MAIT) cells, and γδ-T cells. While ILCs and unconventional T cells together comprise only a small proportion of the total immune cells in the lung, they have been found to promote lung homeostasis and are emerging as contributors to a variety of chronic lung diseases including pulmonary fibrosis, allergic airway inflammation, and chronic obstructive pulmonary disease (COPD). A particularly intriguing trait of ILCs that has recently emerged is their plasticity and ability to alter their gene expression profiles and adapt their function in response to environmental cues. The malleable nature of these cells may aid in rapid responses to pathogen but may also have downstream pathological consequences. The role of ILC2s in Th2 allergic airway responses is becoming apparent but the contribution of other ILCs and unconventional T cells during chronic lung inflammation is poorly described. This review presents an overview of our current understanding of the involvement of ILCs and unconventional T cells in chronic pulmonary diseases.

IL-22 and its receptors are increased in human and experimental COPD and contribute to pathogenesis

Chronic obstructive pulmonary disease (COPD) is the third leading cause of morbidity and death globally. The lack of effective treatments results from an incomplete understanding of the underlying mechanisms driving COPD pathogenesis.Interleukin (IL)-22 has been implicated in airway inflammation and is increased in COPD patients. However, its roles in the pathogenesis of COPD is poorly understood. Here, we investigated the role of IL-22 in human COPD and in cigarette smoke (CS)-induced experimental COPD.IL-22 and IL-22 receptor mRNA expression and protein levels were increased in COPD patients compared to healthy smoking or non-smoking controls. IL-22 and IL-22 receptor levels were increased in the lungs of mice with experimental COPD compared to controls and the cellular source of IL-22 included CD4+ T-helper cells, γδ T-cells, natural killer T-cells and group 3 innate lymphoid cells. CS-induced pulmonary neutrophils were reduced in IL-22-deficient (Il22 -/-) mice. CS-induced airway remodelling and emphysema-like alveolar enlargement did not occur in Il22 -/- mice. Il22 -/- mice had improved lung function in terms of airway resistance, total lung capacity, inspiratory capacity, forced vital capacity and compliance.These data highlight important roles for IL-22 and its receptors in human COPD and CS-induced experimental COPD.

The association between blood eosinophil percent and bacterial infection in acute exacerbation of chronic obstructive pulmonary disease

Introduction: The use of antibiotics is based on the clinician's experience and judgment, and antibiotics may often be overused in the treatment of acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Eosinophils have been studied as biomarkers of bacterial infection and prognostic factors in chronic obstructive pulmonary disease and AECOPD. Thus, the purpose of this study was to determine whether eosinophils could be used to determine bacterial infection in AECOPD events. Methods: We retrospectively analyzed the medical records of patients admitted to Korea University Guro Hospital for AECOPD between January 2011 and May 2017. Data pertaining to baseline characteristics, results of previous pulmonary function tests, treatment information during the admission period, and history of pulmonary treatment were collected before admission. Results: A total of 736 AECOPD events were eligible for inclusion and were divided into two groups based on the eosinophil count: those involving eosinophil counts of less than 2% (546 events) and those involving counts of 2% or more (190 events). In univariate analysis, the only bacterial pathogen identification events and bacterial-viral pathogen co-identification events were significantly more frequent in the group with eosinophil counts of less than 2% (P=0.010 and P=0.001, respectively). In logistic regression analysis, the rates of only bacterial pathogen identification [odds ratios =1.744; 95% confidence interval, 1.107-2.749; P=0.017] and bacterial-viral pathogen co-identification [odds ratios=2.075; 95% confidence interval, 1.081-3.984; P=0.028] were higher in the group with eosinophil count less than 2%. Conclusion: In conclusion, eosinophil counts of less than 2% are potential indicators of a bacterial infection in AECOPD events. Eosinophils could thus serve as a reference for the use of antibiotics in AECOPD treatment.

Cytotoxic lymphocytes in COPD airways: increased NK cells associated with disease, iNKT and NKT-like cells with current smoking

BACKGROUND

Cytotoxic lymphocytes are increased in the airways of COPD patients. Whether this increase is driven primarily by the disease or by smoking is not clear, nor whether it correlates with the rate of decline in lung function.

METHODS

Bronchoscopy with BAL was performed in 52 subjects recruited from the longitudinal OLIN COPD study according to pre-determined criteria; 12 with COPD and a rapid decline in lung function (loss of FEV₁ ≥ 60 ml/year), 10 with COPD and a non-rapid decline in lung function (loss of FEV₁ ≤ 30 ml/year), 15 current and ex-smokers and 15 non-smokers with normal lung function. BAL lymphocyte subsets were determined using flow cytometry.

RESULTS

In BAL fluid, the proportions of NK, iNKT and NKT-like cells all increased with pack-years. Within the COPD group, NK cells - but not iNKT or NKT-like cells - were significantly elevated also in subjects that had quit smoking. In contrast, current smoking was associated with a marked increase in iNKT and NKT-like cells but not in NK cells. Rate of lung function decline did not significantly affect any of the results.

CONCLUSIONS

In summary, increased proportions of NK cells in BAL fluid were associated with COPD; iNKT and NKT-like cells with current smoking but not with COPD. Interestingly, NK cell percentages did not normalize in COPD subjects that had quit smoking, indicating that these cells might play a role in the continued disease progression seen in COPD even after smoking cessation.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT02729220 .

Lipid-Reactive T Cells in Immunological Disorders of the Lung

Regulation of T cell-mediated immunity in the lungs is critical for prevention of immune-related lung disorders and for host protection from pathogens. While the prevalent view of pulmonary T cell responses is based on peptide recognition by antigen receptors, called T cell receptors (TCR), on the T cell surface in the context of classical major histocompatibility complex (MHC) molecules, novel pathways involving the presentation of lipid antigens by cluster of differentiation 1 (CD1) molecules to lipid-reactive T cells are emerging as key players in pulmonary immune system. Whereas, genetic conservation of group II CD1 (CD1d) in mouse and human genomes facilitated numerous in vivo studies of CD1d-restricted invariant natural killer T (iNKT) cells in lung diseases, the recent development of human CD1-transgenic mice has made it possible to examine the physiological roles of group I CD1 (CD1a-c) molecules in lung immunity. Here, we discuss current understanding of the biology of CD1-reactive T cells with a specific focus on their roles in several pulmonary disorders.

The Pathophysiological Relevance of the iNKT Cell/Mononuclear Phagocyte Crosstalk in Tissues

CD1d-restricted Natural Killer T (NKT) cells are regarded as sentinels of tissue integrity by sensing local cell stress and damage. This occurs via recognition of CD1d-restricted lipid antigens, generated by stress-related metabolic changes, and stimulation by inflammatory cytokines, such as IL-12 and IL-18. Increasing evidence suggest that this occurs mainly upon NKT cell interaction with CD1d-expressing cells of the Mononuclear Phagocytic System, i.e., monocytes, macrophages and DCs, which patrol parenchymatous organs and mucosae to maintain tissue homeostasis and immune surveillance. In this review, we discuss critical examples of this crosstalk, presenting the known underlying mechanisms and their effects on both cell types and the environment, and suggest that the interaction with CD1d-expressing mononuclear phagocytes in tissues is the fundamental job of NKT cells.

Deficiency of innate-like T lymphocytes in chronic obstructive pulmonary disease

Background

Based on the phenotypic and functional characteristics unconventional T-lymphocytes such as invariant natural killer T (iNKT) cells and mucosal-associated invariant T (MAIT) cells link the innate and adaptive immune responses. Up to now data are scarce about their involvement in pulmonary disorders including chronic obstructive pulmonary disease (COPD). This study explores simultaneously the frequencies of iNKT and MAIT cells in the peripheral blood and sputum of stable and exacerbating COPD patients.

Methods

By means of multicolor flow cytometry frequencies of total iNKT and MAIT cells and their subsets were enumerated in peripheral blood and sputum samples of healthy controls, and COPD patients. In addition, gene expression of TCR for iNKT, MAIT cells, and CD1d, MR1 were assessed by qPCR in the study cohorts.

Results

Percentages of total iNKT and MAIT cells were dramatically dropped in blood, and reduced numbers of iNKT cells were observed in the sputum of COPD patients. Furthermore decreased DN and increased CD4+ iNKT subsets, while increased DN and decreased CD8+ MAIT subpopulations were measured in the blood of COPD patients. Reduced invariant TCR mRNA levels in COPD patients had confirmed these previous findings. The mRNA expression of CD1d and MR1 were increased in stable and exacerbating COPD patients; however both molecules were decreased upon antibiotic and systemic steroid treatments.

Conclusions

Our results support the notion that both invariant T-cell populations are affected in COPD. Further detailed analysis of invariant T cells could shed more light into the complex interactions of these lymphocyte groups in COPD pathogenesis.

Electronic supplementary material

The online version of this article (10.1186/s12931-017-0671-1) contains supplementary material, which is available to authorized users.

Effects of urban coarse particles inhalation on oxidative and inflammatory parameters in the mouse lung and colon

Background

Air pollution is a recognized aggravating factor for pulmonary diseases and has notably deleterious effects on asthma, bronchitis and pneumonia. Recent studies suggest that air pollution may also cause adverse effects in the gastrointestinal tract. Accumulating experimental evidence shows that immune responses in the pulmonary and intestinal mucosae are closely interrelated, and that gut-lung crosstalk controls pathophysiological processes such as responses to cigarette smoke and influenza virus infection. Our first aim was to collect urban coarse particulate matter (PM) and to characterize them for elemental content, gastric bioaccessibility, and oxidative potential; our second aim was to determine the short-term effects of urban coarse PM inhalation on pulmonary and colonic mucosae in mice, and to test the hypothesis that the well-known antioxidant N-acetyl-L-cysteine (NAC) reverses the effects of PM inhalation.

Results

The collected PM had classical features of urban particles and possessed oxidative potential partly attributable to their metal fraction. Bioaccessibility study confirmed the high solubility of some metals at the gastric level. Male mice were exposed to urban coarse PM in a ventilated inhalation chamber for 15 days at a concentration relevant to episodic elevation peak of air pollution. Coarse PM inhalation induced systemic oxidative stress, recruited immune cells to the lung, and increased cytokine levels in the lung and colon. Concomitant oral administration of NAC reversed all the observed effects relative to the inhalation of coarse PM.

Conclusions

Coarse PM-induced low-grade inflammation in the lung and colon is mediated by oxidative stress and deserves more investigation as potentiating factor for inflammatory diseases.

Electronic supplementary material

The online version of this article (10.1186/s12989-017-0227-z) contains supplementary material, which is available to authorized users.

Th17 cytokines: novel potential therapeutic targets for COPD pathogenesis and exacerbations

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease of the airways caused mainly by cigarette smoke exposure. COPD progression is marked by exacerbations of the disease, often associated with infections. Recent data show the involvement in COPD pathophysiology of interleukin (IL)-17 and IL-22, two cytokines that are important in the control of lung inflammation and infection. During the initiation and progression of the disease, increased IL-17 secretion causes neutrophil recruitment, leading to chronic inflammation, airways obstruction and emphysema. In the established phase of COPD, a defective IL-22 response facilitates pathogen-associated infections and disease exacerbations. Altered production of these cytokines involves a complex network of immune cells and dysfunction of antigen-presenting cells. In this review, we describe current knowledge on the involvement of IL-17 and IL-22 in COPD pathophysiology at steady state and during exacerbations, and discuss implications for COPD management and future therapeutic approaches.

Influenza A virus-induced release of interleukin-10 inhibits the anti-microbial activities of invariant natural killer T cells during invasive pneumococcal superinfection

During influenza A virus (IAV) infection, changes in the lung's physical and immunological defenses predispose the host to bacterial superinfections. Invariant natural killer T (iNKT) cells are innate-like T lymphocytes that have beneficial or harmful functions during infection. We investigated the iNKT cells' role in a model of invasive pneumococcal superinfection. The use of Jα18^-/- mice indicated that iNKT cells limited susceptibility to influenza-pneumococcal infection and reduced the lethal synergism. This role did not depend on immune-based anti-bacterial mechanisms. At the time of bacterial exposure, iNKT cells from IAV-experienced mice failed to produce antipneumococcal interferon-γ and adoptive transfer of fresh iNKT cells before Streptococcus pneumoniae challenge did not restore anti-bacterial host defenses. Impaired iNKT cell activation in superinfected animals was related to the IAV-induced immunosuppressive cytokine interleukin-10 (IL-10), rather than to an intrinsic functional defect. IL-10 dampened the activation of iNKT cells in response to pneumococci by inhibiting the production of IL-12 by pulmonary monocyte-derived dendritic cells. Neutralization of IL-10 restored iNKT cell activation and tends to increase resistance to secondary bacterial infection. Overall, iNKT cells have a beneficial role (upstream of bacterial colonization) in controlling influenza-pneumococcal superinfection, although they represent novel targets of immunosuppression at the time of bacterial challenge.

Interleukin-22 protects against non-typeable Haemophilus influenzae infection: alteration during chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is a major health problem becoming a leading cause of morbidity and mortality worldwide. A large part of these disorders is associated with acute exacerbations resulting from infection by bacteria, such as non-typeable Haemophilus influenzae (NTHi). Our understanding of the pathogenesis of these exacerbations is still elusive. We demonstrate herein that NTHi infection of mice chronically exposed to cigarette smoke (CS), an experimental model of chronic obstructive pulmonary disease (COPD), not only causes acute pulmonary inflammation but also impairs the production of interleukin (IL)-22, a cytokine with potential anti-bacterial activities. We also report that mice lacking IL-22, as well as mice exposed to CS, have a delayed clearance of NTHi bacteria and display enhanced alveolar wall thickening and airway remodeling compared with controls. Supplementation with IL-22 not only boosted bacterial clearance and the production of anti-microbial peptides but also limited lung damages induced by infection both in IL-22-/- and CS-exposed mice. In vitro exposure to CS extract altered the NTHi-induced IL-22 production by spleen cells. This study shows for the first time that a defect in IL-22 is involved in the acute exacerbation induced by NTHi infection during experimental COPD and opens the way to innovative therapeutic strategies.

Cigarette smoke alters the ability of human dendritic cells to promote anti-Streptococcus pneumoniae Th17 response

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with chronic inflammation and impaired immune response to pathogens leading to bacteria-induced exacerbation of the disease. A defect in Th17 cytokines in response to Streptococcus pneumoniae, a bacteria associated with COPD exacerbations, has been recently reported. Dendritic cells (DC) are professional antigen presenting cells that drive T-cells differentiation and activation. In this study, we hypothesized that exposure to cigarette smoke, the main risk factor of COPD, might altered the pro-Th17 response to S. pneumoniae in COPD patients and human DC.

METHODS

Pro-Th1 and -Th17 cytokine production by peripheral blood mononuclear cells (PBMC) from COPD patients was analyzed and compared to those from smokers and non-smokers healthy subjects. The effect of cigarette smoke extract (CSE) was analyzed on human monocyte-derived DC (MDDC) from controls exposed or not to S. pneumoniae. Bacteria endocytosis, maturation of MDDC and secretion of cytokines were assessed by flow cytometry and ELISA, respectively. Implication of the oxidative stress was analyzed by addition of antioxidants and mitochondria inhibitors. In parallel, MDDC were cocultured with autologous T-cells to analyze the consequence on Th1 and Th17 cytokine production.

RESULTS

PBMC from COPD patients exhibited defective production of IL-1β, IL-6, IL-12 and IL-23 to S. pneumoniae compared to healthy subjects and smokers. CSE significantly reduced S. pneumoniae-induced MDDC maturation, secretion of pro-Th1 and -Th17 cytokines and activation of Th1 and Th17 T-cell responses. CSE exposure was also associated with sustained CXCL8 secretion, bacteria endocytosis and mitochondrial oxidative stress. Antioxidants did not reverse these effects. Inhibitors of mitochondrial electron transport chain partly reproduced inhibition of S. pneumoniae-induced MDDC maturation but had no effect on cytokine secretion and T cell activation.

CONCLUSIONS

We observed a defective pro-Th1 and -Th17 response to bacteria in COPD patients. CSE exposure was associated with an inhibition of DC capacity to activate antigen specific T-cell response, an effect that seems to be not only related to oxidative stress. These results suggest that new therapeutics boosting this response in DC may be helpful to improve treatment of COPD exacerbations.

Role Of Hif2α Oxygen Sensing Pathway In Bronchial Epithelial Club Cell Proliferation

Oxygen-sensing pathways executed by the hypoxia-inducible factors (HIFs) induce a cellular adaptive program when oxygen supply becomes limited. However, the role of the HIF oxygen-sensing pathway in the airway response to hypoxic stress in adulthood remains poorly understood. Here we found that in vivo exposure to hypoxia led to a profound increase in bronchial epithelial cell proliferation mainly confined to Club (Clara) cells. Interestingly, this response was executed by hypoxia-inducible factor 2α (HIF2α), which controls the expression of FoxM1, a recognized proliferative factor of Club cells. Furthermore, HIF2α induced the expression of the resistin-like molecules α and β (RELMα and β), previously considered bronchial epithelial growth factors. Importantly, despite the central role of HIF2α, this proliferative response was not initiated by in vivo Vhl gene inactivation or pharmacological inhibition of prolyl hydroxylase oxygen sensors, indicating the molecular complexity of this response and the possible participation of other oxygen-sensing pathways. Club cells are principally involved in protection and maintenance of bronchial epithelium. Thus, our findings identify a novel molecular link between HIF2α and Club cell biology that can be regarded as a new HIF2α-dependent mechanism involved in bronchial epithelium adaptation to oxygen fluctuations.

Repeated Activation of Lung Invariant NKT Cells Results in Chronic Obstructive Pulmonary Disease-Like Symptoms

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation, mucus hypersecretion, and emphysema, which lead to reduced lung function and breathlessness. The pathologies of COPD are due to an abnormal immune response. Invariant natural killer T (iNKT) cells are an important population of innate lymphocytes and have been implicated in the regulation of immune responses associated with a broad range of diseases including COPD. We have here analyzed the role of iNKT cells in a model of COPD induced by repeated intranasal administration of iNKT cell agonist α-galactosylceramide (α-GalCer). Our results demonstrated that mice that received repeated intranasal administration of α-GalCer had molecular and inflammatory features of COPD including airway inflammation with significant increases in infiltration of macrophages and lymphocytes, CD8⁺ T cells, as well as proinflammatory cytokines IL-6 and TNF-α. In particular, these mice also showed the presence of pulmonary emphysema, mucus production, and pulmonary fibrosis. Furthermore, neutralization of IL-4 reduced α-GalCer induced emphysema. This study indicates the importance of iNKT cells in the pathogenesis of COPD by an IL-4 dependent mechanism.

[Proteomic analysis of exhaled breath condensate for diagnosis of pathologies of the respiratory system]

Study of the proteomic composition of exhaled breath condensate (EBC), is a promising non-invasive method for the diagnosis of the respiratory tract diseases in patients. In this study the EBC proteomic composition of the 79 donors, including patients with different pathologies of the respiratory system has been investigated. Cytoskeletal keratins type II (1, 2, 3, 4, 5, 6) and cytoskeletal keratins the type I (9, 10, 14, 15, 16) were invariant for all samples. Analyzing the frequency of occurrence of proteins in different groups of examined patients, several categories of protein have been recognized: found in all pathologies (Dermcidin, Alpha-1-microglobulin, SHROOM3), found in several pathologies (CSTA, LCN1, JUP, PIP, TXN), and specific for a single pathology (PRDX1, Annexin A1/A2). The EBC analysis by HPLC-MS/MS can be used to identify potential protein markers characteristic for pathologies such as chronic obstructive pulmonary disease (PRDX1) and pneumonia (Annexin A1/A2).

IL-22 Defect During Streptococcus pneumoniae Infection Triggers Exacerbation of Chronic Obstructive Pulmonary Disease

Progression of chronic obstructive pulmonary disease (COPD) is linked to episodes of exacerbations caused by bacterial infections due to Streptococcus pneumoniae. Our objective was to identify during COPD, factors of susceptibility to bacterial infections among cytokine network and their role in COPD exacerbations. S. pneumoniae was used to sub-lethally challenge mice chronically exposed to air or cigarette smoke (CS) and to stimulate peripheral blood mononuclear cells (PBMC) from non-smokers, smokers and COPD patients. The immune response and the cytokine production were evaluated. Delayed clearance of the bacteria and stronger lung inflammation observed in infected CS-exposed mice were associated with an altered production of IL-17 and IL-22 by innate immune cells. This defect was related to a reduced production of IL-1β and IL-23 by antigen presenting cells. Importantly, supplementation with recombinant IL-22 restored bacterial clearance in CS-exposed mice and limited lung alteration. In contrast with non-smokers, blood NK and NKT cells from COPD patients failed to increase IL-17 and IL-22 levels in response to S. pneumoniae, in association with a defect in IL-1β and IL-23 secretion. This study identified IL-17 and IL-22 as susceptibility factors in COPD exacerbation. Therefore targeting such cytokines could represent a potent strategy to control COPD exacerbation.

Innate cellular sources of interleukin-17A regulate macrophage accumulation in cigarette- smoke-induced lung inflammation in mice

Cigarette smoke (CS) is the major cause of chronic obstructive pulmonary disease (COPD). Interleukin-17A (IL-17A) is a pivotal cytokine that regulates lung immunity and inflammation. The aim of the present study was to investigate how IL-17A regulates CS-induced lung inflammation in vivo. IL-17A knockout (KO) mice and neutralization of IL-17A in wild-type (WT) mice reduced macrophage and neutrophil recruitment and chemokine (C-C motif) ligand 2 (CCL2), CCL3 and matrix metalloproteinase (MMP)-12 mRNA expression in response to acute CS exposure. IL-17A expression was increased in non-obese diabetic (NOD) severe combined immunodeficiency SCID) mice with non-functional B- and T-cells over a 4-week CS exposure period, where macrophages accumulated to the same extent as in WT mice. Gene expression analysis by QPCR (quantitative real-time PCR) of isolated immune cell subsets detected increased levels of IL-17A transcript in macrophages, neutrophils and NK/NKT cells in the lungs of CS-exposed mice. In order to further explore the relative contribution of innate immune cellular sources, intracellular IL-17A staining was performed. In the present study, we demonstrate that CS exposure primes natural killer (NK), natural killer T (NKT) and γδ T-cells to produce more IL-17A protein and CS alone increased the frequency of IL17+ γδ T-cells in the lung, whereas IL-17A protein was not detected in macrophages and neutrophils. Our data suggest that activation of innate cellular sources of IL-17A is an essential mediator of macrophage accumulation in CS-exposed lungs. Targeting non-conventional T-cell sources of IL-17A may offer an alternative strategy to reduce pathogenic macrophages in COPD.

T, B, and NKT Cells in Systemic Inflammation in Obstructive Sleep Apnoea

Background. Obstructive sleep apnoea syndrome (OSAS) brings risk of serious complications. The study objective was to assess elements of the cellular immune response in the course of OSAS. Methods. Peripheral blood (PB) lymphocytes: T, B, NK, NKT-like, Th, Tc, and HLA DR+ T cells were evaluated by flow cytometry of 48 OSA patients; the concentration of adiponectin, interleukin 1β, and TNFα was measured by ELISA method. The OSA complication score was developed and used for statistical analysis. Results. The proportion of B cells and Th/Tc ratio were significantly lower in the BP of OSA patients when compared with control subjects (median 7.9 versus 10.9%, 0.9 versus 1.5, p < 0.05). The proportion of Tc, NK, NKT-like, and HLADR positive T cells were elevated in OSA patients when compared with healthy subjects (36.4 versus 26.8, 15.5 versus 8.5, 5.7 versus 3.0, and 8.4 versus 4.5%, p < 0.05, resp.) and were more pronounced in patients with metabolic syndrome. The grade of OSA complication score correlated with systemic inflammation markers and the proportion of B cells. The value of adiponectin/BMI ratio correlated significantly with SpO₂ (r = 0.31, p < 0.05), CRP (r = −0.35, p < 0.05), TNFα concentration (r = −0.36, p < 0.05), and proportion of B cells (r = 0.32, p < 0.05). Conclusion. Lymphocytes B, Tc, NK, NKT-like, and adiponectin are involved in systemic immune response in OSA patients possibly predisposing them to cardiovascular and metabolic complications.

Enhancement of the acrolein-induced production of reactive oxygen species and lung injury by GADD34

Chronic obstructive pulmonary disease (COPD) is characterized by lung destruction and inflammation. As a major compound of cigarette smoke, acrolein plays a critical role in the induction of respiratory diseases. GADD34 is known as a growth arrest and DNA damage-related gene, which can be overexpressed in adverse environmental conditions. Here we investigated the effects of GADD34 on acrolein-induced lung injury. The intranasal exposure of acrolein induced the expression of GADD34, developing the pulmonary damage with inflammation and increase of reactive oxygen species (ROS). Conversely, the integrality of pulmonary structure was preserved and the generation of ROS was reduced in GADD34-knockout mice. Acrolein-induced phosphorylation of eIF2α in GADD34-knockout epithelial cells by shRNA protected cell death by reducing misfolded protein-caused oxidative stress. These data indicate that GADD34 participates in the development of acrolein-induced lung injury.