Pretreatment circulating MAIT cells, neutrophils, and periostin predicted the real-world response after 1-year mepolizumab treatment in asthmatics.

BACKGROUND: Mepolizumab treatment improves symptom control and quality of life and reduces exacerbations in patients with severe eosinophilic asthma. However, biomarkers that predict therapeutic effectiveness must be determined for use in precision medicine. Herein, we elucidated the dynamics of various parameters before and after treatment as well as patient characteristics predictive of clinical responsiveness to mepolizumab after 1-year treatment. METHODS: Twenty-seven patients with severe asthma were treated with mepolizumab for one year. Asthma control test scores, pulmonary function tests, fractional exhaled nitric oxide levels, and blood samples were evaluated. Additionally, we explored the role of CD69-positive mucosal-associated invariant T (MAIT) cells as a candidate biomarker for predicting treatment effectiveness by evaluating an OVA-induced asthma murine model using MR1 knockout mice, where MAIT cells were absent. RESULTS: The frequencies of CD69-positive group 1 innate lymphoid cells, group 3 innate lymphoid cells, natural killer cells, and MAIT cells decreased after mepolizumab treatment. The frequency of CD69-positive MAIT cells and neutrophils was lower and serum periostin levels were higher in responders than in non-responders. In the OVA-induced asthma murine model, CD69-positive MAIT cell count in the whole mouse lung was significantly higher than that in the control mice. Moreover, OVA-induced eosinophilic airway inflammation was exacerbated in the MAIT cell-deficient MR1 knockout mice. CONCLUSIONS: This study shows that circulating CD69-positive MAIT cells, neutrophils, and serum periostin might predict the real-world response after 1-year mepolizumab treatment. Furthermore, MAIT cells potentially have a protective role against type 2 airway inflammation.

MAP3K19 Affects TWEAK-Induced Response in Cultured Bronchial Epithelial Cells and Regulates Allergic Airway Inflammation in an Asthma Murine Model.

The mitogen-activated protein kinase (MAPK) signaling pathway is involved in the epithelial-mesenchymal transition (EMT) and asthma; however, the role of mitogen-activated protein kinase kinase kinase 19 (MAP3K19) remains uncertain. Therefore, we investigated the involvement of MAP3K19 in in vitro EMT and ovalbumin (OVA)-induced asthma murine models. The involvement of MAP3K19 in the EMT and the production of cytokines and chemokines were analyzed using a cultured bronchial epithelial cell line, BEAS-2B, in which MAP3K19 was knocked down using small interfering RNA. We also evaluated the involvement of MAP3K19 in the OVA-induced asthma murine model using Map3k19-deficient (MAP3K19-/-) mice. Transforming growth factor beta 1 (TGF-ß1) and tumor necrosis factor-like weak inducer of apoptosis (TWEAK) induced the MAP3K19 messenger RNA (mRNA) expression in the BEAS-2B cells. The knockdown of MAP3K19 enhanced the reduction in E-cadherin mRNA and the production of regulated upon activation normal T cell express sequence (RANTES) via stimulation with TWEAK alone or with the combination of TGF-ß1 and TWEAK. Furthermore, the expression of MAP3K19 mRNA was upregulated in both the lungs and tracheas of the mice in the OVA-induced asthma murine model. The MAP3K19-/- mice exhibited worsened eosinophilic inflammation and an increased production of RANTES in the airway epithelium compared with the wild-type mice. These findings indicate that MAP3K19 suppressed the TWEAK-stimulated airway epithelial response, including adhesion factor attenuation and RANTES production, and suppressed allergic airway inflammation in an asthma mouse model, suggesting that MAP3K19 regulates allergic airway inflammation in patients with asthma.

Pretreatment Frequency of Circulating Th17 Cells and FeNO Levels Predicted the Real-World Response after 1 Year of Benralizumab Treatment in Patients with Severe Asthma.

Benralizumab treatment reduces exacerbations and improves symptom control and quality of life in patients with severe eosinophilic asthma. However, the determination of biomarkers that predict therapeutic effectiveness is required for precision medicine. Herein, we elucidated the dynamics of various parameters before and after treatment as well as patient characteristics predictive of clinical effectiveness after 1 year of benralizumab treatment in severe asthma in a real-world setting. Thirty-six patients with severe asthma were treated with benralizumab for 1 year. Lymphocyte subsets in peripheral blood samples were analyzed using flow cytometry. Treatment effectiveness was determined based on the ACT score, forced expiratory volume in 1 s (FEV1), and the number of exacerbations. Benralizumab provided symptomatic improvement in severe asthma. Benralizumab significantly decreased peripheral blood eosinophil and basophil counts and the frequencies of regulatory T cells (Tregs), and increased the frequencies of Th2 cells. To our knowledge, this is the first study to show benralizumab treatment increasing circulating Th2 cells and decreasing circulating Tregs. Finally, the ROC curve to discriminate patients who achieved clinical effectiveness of benralizumab treatment revealed that the frequency of circulating Th17 cells and FeNO levels might be used as parameters for predicting the real-world response of benralizumab treatment in patients with severe asthma.

Chitin induces steroid-resistant airway inflammation and airway hyperresponsiveness in mice.

BACKGROUND: Previous reports have shown that pathogen-associated patterns (PAMPs) induce the production of interleukin (IL)-1ß in macrophages. Moreover, studies using mouse models also suggest that chitin, which acts as a PAMP, induces adjuvant effects and eosinophilic infiltration in the lung. Thus, we investigated the effects of inhaled chitin in mouse models. METHODS: We developed mouse models of inhaled chitin particle-induced airway inflammation and steroid-resistant ovalbumin (OVA)-induced airway inflammation. Some experimental groups of mice were treated additionally with dexamethasone (DEX). Murine alveolar macrophages (AMs), which were purified from bronchoalveolar lavage (BAL) fluids, were incubated with chitin, and treated with or without DEX. RESULTS: The numbers of total cells, AMs, lymphocytes, eosinophils, and neutrophils among BAL-derived cells, as well as the IL-1ß levels in BAL fluids and the numbers of IL-1ß-positive cells in lung, were significantly increased by chitin stimulation. Airway hyperresponsiveness (AHR) was aggravated in mice of the chitin inflammation model compared to control animals. The production of IL-1ß was significantly increased in murine AMs by chitin treatment, but DEX administration did not inhibit this chitin-induced IL-1ß production. Furthermore, in mouse models, DEX treatment inhibited the OVA-induced airway inflammation and AHR but not the airway inflammation and AHR induced by chitin or the combination of OVA and chitin. CONCLUSIONS: These results suggest that inhaled chitin induces airway inflammation, AHR, and the production of IL-1ß. Furthermore, our findings demonstrate for the first time that inhaled chitin induces steroid-resistant airway inflammation and AHR. Inhaled chitin may contribute to features of steroid-resistant asthma.

Difference between two exhaled nitric oxide analyzers, NIOX VERO® electrochemical hand-held analyzer and NOA280i® chemiluminescence stationary analyzer.

BACKGROUND: Fractional exhaled nitric oxide (FENO) is useful for the evaluation of eosinophilic airway inflammation, including that seen in asthma. Although a new electrochemical hand-held FENO analyzer, the NIOX VERO® (Aerocrine AB, Solna, Sweden), is clinically convenient to use, it has not been fully compared with the chemiluminescence stationary electrochemical analyzer NOA280i® (Sievers Instruments, Boulder, CO, USA) in terms of the level of measured FENO. The aim of this study was to determine whether there is a difference between the two analyzers. METHODS: The FENO levels measured with both NIOX VERO® and NOA280i® were evaluated in 1,369 adults at Juntendo University Hospital from May 2016 to October 2016. RESULTS: The median FENO level measured with the NIOX VERO® was significantly lower than that measured with the NOA280i® (41 ppb, range 5-368 ppb vs. 29 ppb, range 5-251 ppb; p < 0.001). There was a strong positive correlation in the measurement of FENO level between the NOA280i® and the NIOX VERO® (r = 0.942, p < 0.001). The following conversion equation was calculated: FENO (NOA280i®) = 1.362 (SE, 0.661) + 1.384 (SE, 0.021) × FENO (NIOX VERO®). CONCLUSIONS: To our best knowledge, we have provided the first report showing that the measured FENO level with the NIOX VERO® was approximately 30% lower than that with the NOA280i® and that there was a significant correlation between the measurements of these two devices. The correction equation that we provided may help assess the data obtained by these two analyzers. Abbreviations ATS American Thoracic Society BMI Body mass index ERS European Respiratory Society FENO Fractional exhaled nitric oxide GINA Global Initiative for Asthma NO Nitric oxide ppb Parts per billion ROC Receiver operating characteristic SD Standard deviation.

Characterization of tenascin-C as a novel biomarker for asthma: utility of tenascin-C in combination with periostin or immunoglobulin E.

BACKGROUND: Extracellular matrix proteins tenascin-C (TNC) and periostin, which were identified as T-helper cell type 2 cytokine-induced genes in human bronchial epithelial cells, accumulate in the airway basement membrane of asthmatic patients. Although serum periostin has been accepted as a type 2 biomarker, serum TNC has not been evaluated as a systemic biomarker in asthma. Therefore, the objective of this study was to evaluate whether serum TNC can serve as a novel biomarker for asthma. METHODS: We evaluated 126 adult patients with mild to severe asthma. Serum TNC, periostin, and total IgE concentrations were quantified using enzyme-linked immunosorbent assays. RESULTS: Serum TNC levels were significantly higher in patients with severe asthma and high serum total IgE levels. Patients with both high serum TNC (> 37.16 ng/mL) and high serum periostin (> 95 ng/mL) levels (n = 20) or patients with both high serum TNC and high serum total IgE (> 100 IU/mL) levels (n = 36) presented higher disease severity and more severe airflow limitation than patients in other subpopulations. CONCLUSIONS: To our knowledge, this is the first study to show that serum TNC levels in asthmatic patients are associated with clinical features of asthma and that the combination of serum TNC and periostin levels or combination of serum TNC and total IgE levels were more useful for asthma than each single marker, suggesting that serum TNC can serve as a novel biomarker for asthma.

Combination of TWEAK and TGF-ß1 induces the production of TSLP, RANTES, and TARC in BEAS-2B human bronchial epithelial cells during epithelial-mesenchymal transition.

AIM OF THE STUDY: In patients with asthma, chronic inflammatory processes and the subsequent remodeling of the airways contribute to the symptoms and the pathophysiological changes. Epithelial-mesenchymal transition (EMT) is thought to play an important role in tissue remodeling. Previous reports show that tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) is a cytokine of the TNF superfamily, exerts pro-inflammatory effects, and enhances transforming growth factor (TGF)-ß-induced EMT in bronchial epithelial cells. In this study, we investigated the TWEAK-induced cytokine and chemokine production in the human bronchial epithelial cell line BEAS-2B during EMT. MATERIALS AND METHODS: Quantitative real-time RT-PCR, enzyme-linked immunosorbent assays, western blotting, and immunohistochemistry were used to define the production of cytokines and chemokines. RESULTS: We found that TWEAK increases mRNA and protein levels of thymic stromal lymphopoietin (TSLP), monocyte chemoattractant protein -1 (MCP-1), regulated upon activation normal T cell express sequence (RANTES), and IL-8 in BEAS-2B bronchial epithelial cells. Moreover, co-treatment with TWEAK and TGF-ß1 induces not only features of EMT but also enhances the production of TSLP and RANTES. Thymus- and activation-regulated chemokines (TARC) production is induced by the co-treatment of TWEAK and TGF-ß1 but not by TWEAK or TGF-ß1 stimulation alone. Furthermore, the increased mRNA expression of TSLP and RANTES after co-treatment with TWEAK and TGF-ß1 is prevented by inhibitors of Smad-independent signaling pathways. CONCLUSIONS: In the present study, we have revealed a novel mechanism for the production of asthma-related cytokines and chemokines in EMT driven by the co-stimulation with TWEAK and TGF-ß1. We conclude that cellular EMT processes caused by TWEAK and TGF-ß1 may contribute to chronic airway inflammation and remodeling.

Circulating activated innate lymphoid cells and mucosal-associated invariant T cells are associated with airflow limitation in patients with asthma.

BACKGROUND: A variety of innate subsets of lymphoid cells such as natural killer (NK) cells, several populations of innate lymphoid cells (ILCs), and mucosal-associated invariant T (MAIT) cells as innate-like T lymphocytes are involved in asthma and may have important effector functions in asthmatic immune responses. In the present study, we investigated whether NK cells, ILCs, and MAIT cells in the peripheral blood of patients with asthma would be associated with clinical asthma parameters. METHODS: We recruited 75 adult patients with mild to severe asthma. The peripheral blood mononuclear cells in peripheral venous blood samples from the patients were purified and stained with different combinations of appropriate antibodies. The cells were analyzed by flow cytometry. RESULTS: The percentage of activated (i.e., CD69+) NK cells in the total NK cell population was negatively correlated with FEV1% which is calculated by the forced expiratory volume in 1 s (FEV1)/the forced vital capacity (FVC). The percentages of CD69+ ILC1s and ILC2s were negatively correlated with FEV1% and %FEV1. The percentage of CD69+ ILC3s was positively correlated with BMI, and the percentage of CD69+ MAIT cells was negatively correlated with FEV1%. Moreover, the percentage of CD69+ NK cells, ILC1s, ILC2s, ILC3s, and MAIT cells were positively correlated with each other. CONCLUSIONS: For the first time, our data showed that activated NK cells, ILC1s, ILC2s, ILC3s, and MAIT cells were positively correlated with each other and may be associated with airflow limitation in patients with asthma.

Leukotriene B4 receptor type 2 protects against pneumolysin-dependent acute lung injury.

Although pneumococcal infection is a serious problem worldwide and has a high mortality rate, the molecular mechanisms underlying the lethality caused by pneumococcus remain elusive. Here, we show that BLT2, a G protein-coupled receptor for leukotriene B4 and 12(S)-hydroxyheptadecatrienoic acid (12-HHT), protects mice from lung injury caused by a pneumococcal toxin, pneumolysin (PLY). Intratracheal injection of PLY caused lethal acute lung injury (ALI) in BLT2-deficient mice, with evident vascular leakage and bronchoconstriction. Large amounts of cysteinyl leukotrienes (cysLTs), classically known as a slow reactive substance of anaphylaxis, were detected in PLY-treated lungs. PLY-dependent vascular leakage, bronchoconstriction, and death were markedly ameliorated by treatment with a CysLT1 receptor antagonist. Upon stimulation by PLY, mast cells produced cysLTs that activated CysLT1 expressed in vascular endothelial cells and bronchial smooth muscle cells, leading to lethal vascular leakage and bronchoconstriction. Treatment of mice with aspirin or loxoprofen inhibited the production of 12-HHT and increased the sensitivity toward PLY, which was also ameliorated by the CysLT1 antagonist. Thus, the present study identifies the molecular mechanism underlying PLY-dependent ALI and suggests the possible use of CysLT1 antagonists as a therapeutic tool to protect against ALI caused by pneumococcal infection.

Evaluation of switching low-dose inhaled corticosteroid to pranlukast for step-down therapy in well-controlled patients with mild persistent asthma.

OBJECTIVE: Treatment guidelines for asthma recommend step-down therapy for well-controlled asthma patients. However, the precise strategy for step-down therapy has not been well defined. We investigated whether well-controlled patients with mild persistent asthma can tolerate a step-down therapy of either a reduced dose of inhaled corticosteroid (ICS) or a switch to a leukotriene receptor antagonist (LTRA), pranlukast hydrate. METHODS: We recruited 40 adult patients with mild persistent asthma who were well-controlled for at least 3 months with a low-dose ICS therapy. The patients were randomly assigned to either an ICS dose reduction or a switch to pranlukast for 6 months. RESULTS: FeNO levels in the pranlukast group were significantly increased over that in the ICS group. There were no significant differences between the two groups for lung function, FOT, at the endpoint. The percentage of patients with controlled asthma was 72.2% in the pranlukast group and 90% in the ICS group. No statistically significant difference between the two groups in the percentages of patients with treatment failure was observed. CONCLUSIONS: Patients with mild persistent asthma that is well-controlled by a low dose of ICS can be switched to pranlukast safely for at least 6 months. However, 27.8% of the pranlukast group failed to maintain well-control, and FeNO levels increased with the switch to pranlukast at 6 months. This study was been limited by the small sample size and should therefore be considered preliminary. Further studies are needed to investigate the therapeutic efficacy of LTRA monotherapy as a step-down therapy.

Characteristics of alveolar macrophages from murine models of OVA-induced allergic airway inflammation and LPS-induced acute airway inflammation.

BACKGROUND:  Macrophages include the classically activated pro-inflammatory M1 macrophages (M1s) and alternatively activated anti-inflammatory M2 macrophages (M2s). The M1s are activated by both interferon-γ and Toll-like receptor ligands, including lipopolysaccharide (LPS), and have potent pro-inflammatory activity. In contrast, Th2 cytokines activate the M2s, which are involved in the immune response to parasites, promotion of tissue remodeling, and immune regulatory functions. Although alveolar macrophages (AMs) play an essential role in the pulmonary immune system, little is known about their phenotypes. METHODS:  Quantitative reverse transcription polymerase chain reaction and flow cytometry were used to define the characteristics of alveolar macrophages derived from untreated naïve mice and from murine models of both ovalbumin (OVA)-induced allergic airway inflammation and LPS-induced acute airway inflammation. AMs were co-cultured with CD4(+) T cells and were pulsed with tritiated thymidine to assess proliferative responses. RESULTS:  We characterized in detail murine AMs and found that these cells were not completely consistent with the current M1 versus M2-polarization model. OVA-induced allergic and LPS-induced acute airway inflammation promoted the polarization of AMs towards the current M2-skewed and M1-skewed phenotypes, respectively. Moreover, our data also show that CD11c(+) CD11b(+) AMs from the LPS-treated mice play a regulatory role in antigen-specific T-cell proliferation in vitro. CONCLUSIONS:  These characteristics of AMs depend on the incoming pathogens they encounter and on the phase of inflammation and do not correspond to the current M1 versus M2-polarization model. These findings may facilitate an understanding of their contributions to the pulmonary immune system in airway inflammation.