The transcription factor E4BP4 regulates the production of IL-10 and IL-13 in CD4+ T cells.

The immunoregulatory cytokine interleukin 10 (IL-10) is expressed mainly by T helper type 2 (T(H)2) cells but also by T(H)1 cells during chronic infection. Here we observed plasticity in the expression of IL-10 and IL-13 after chronic T(H)1 stimulation; furthermore, the expression of Il10 and Il13 was regulated by the transcription factor E4BP4. Chronically stimulated E4BP4-deficient (Nfil3(-/-); called 'E4bp4(-/-)' here) T(H)1 cells, regulatory T cells (T(reg) cells) and natural killer T cells (NKT cells) had attenuated expression of IL-10 and IL-13. Enforced expression of E4bp4 initiated the production of IL-10 and IL-13 by conventional T(H)1 cells. E4bp4(-/-) T(H)2 cells showed impairment of IL-10 production with no effect on IL-13. Our results indicate that E4BP4 has multiple functions in controlling the plasticity of IL-13 in T(H)1 cells and IL-10 in T(H)1 cells, T(H)2 cells, T(reg) cells and NKT cells.

Risks of dementia in a general Japanese older population with preserved ratio impaired spirometry: The Hisayama Study.

BACKGROUND: Studies on the association between preserved ratio impaired spirometry (PRISm) and dementia are limited. Indeed, PRISm has often been overlooked or ignored as an index of lung function impairment. Therefore, we investigated the association of PRISm with the risk for the development of dementia in an older Japanese population. METHODS: A total of 1202 community-dwelling, older Japanese participants aged ≥65 years without dementia were followed up for a median of 5.0 years. Participants were categorized by spirometry as follows: normal spirometry (FEV1/FVC ≥0.70 and FEV1 ≥80% predicted), PRISm (≥0.70 and <80%), airflow limitation (AFL) Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 (<0.70 and ≥80%), and AFL GOLD 2 to 4 (<0.70 and <80%). Hazard ratios (HRs) and their 95% confidence intervals (CIs) were computed using a Cox proportional hazards model. RESULTS: During the follow-up period, 122 participants developed dementia. The age- and sex-adjusted incidences of dementia in the participants with normal spirometry, PRISm, AFL GOLD 1, and AFL GOLD 2 to 4 were 20.5, 37.0, 18.4, and 28.6 per 1000 person-years, respectively. Participants with PRISm had a higher risk of dementia (HR 2.04 [95%CI, 1.19-3.49]) than those with normal spirometry after adjusting for confounders. Moreover, both reduced FEV1% predicted values and FVC% predicted values were associated with the risk for dementia. CONCLUSION: PRISm was associated with an increased risk of dementia in a general older Japanese population.

Risks of Mortality and Airflow Limitation in Japanese Individuals with Preserved Ratio Impaired Spirometry.

Rationale: Several Western studies have reported that participants with preserved ratio impaired spirometry (PRISm) have higher risks of airflow limitation (AFL) and death. However, evidence in East Asian populations is limited. Objectives: To investigate the relationship between PRISm and the risks of death and incident AFL in a Japanese population. Methods: A total of 3,032 community-dwelling Japanese participants aged ⩾40 years were seen in follow-up for a median of 5.3 years by annual spirometry examinations. Participants were classified into lung function categories at baseline as follows: normal spirometry (FEV1/FVC ⩾0.70 and FEV1 ⩾80% predicted), PRISm (⩾0.70 and <80%), AFL Global Initiative for Chronic Obstructive Lung Disease 1 (<0.70 and ⩾80%), and AFL Global Initiative for Chronic Obstructive Lung Disease 2-4 (<0.70 and <80%). Hazard ratios (HRs) and their 95% confidence intervals were computed using a Cox proportional hazards model. Measurements and Main Results: During the follow-up period, 131 participants died, 22 of whom died of cardiovascular disease, and 218 participants developed AFL. When examining the prognosis of each baseline lung function category, participants with PRISm had higher risks of all-cause death (HR, 2.20; 95% confidence interval, 1.35-3.59) and cardiovascular death (HR, 4.07; 1.07-15.42) than those with normal spirometry after adjusting for confounders. Moreover, the multivariable-adjusted risk of incident AFL was greater in participants with PRISm than in those with normal spirometry (HR, 2.48; 1.83-3.36). Conclusions: PRISm was associated with higher risks of all-cause and cardiovascular death and a greater risk of the development of AFL in a Japanese community.

Effects of treatment with corticosteroids on human rhinovirus-induced asthma exacerbations in pediatric inpatients: a prospective observational study.

BACKGROUND: Human rhinoviruses (HRVs) infection is a common cause of exacerbations in pediatric patients with asthma. However, the effects of corticosteroids on HRV-induced exacerbations in pediatric asthma are unknown. We conducted a prospective observational study to determine the viral pathogens in school-age pediatric inpatients with asthma exacerbations. We assessed the effects of maintenance inhaled corticosteroids (ICS) on the detection rates of HRV species and treatment periods of systemic corticosteroids during exacerbations on pulmonary lung function after exacerbations. METHODS: Nasopharyngeal samples and clinical information were collected from 59 patients with asthma exacerbations between April 2018 and March 2020. Pulmonary function tests were carried out 3 months after exacerbations in 18 HRV-positive patients. Changes in forced expiratory volume in 1 second (FEV1)% predicted from baseline in a stable state were compared according to the treatment periods of systemic corticosteroids. RESULTS: Fifty-four samples collected from hospitalized patients were analyzed, and viral pathogens were identified in 45 patients (83.3%) using multiplex PCR assay. HRV-A, -B, and -C were detected in 16 (29.6%), one (1.9%), and 16 (29.6%) patients, respectively. The detection rates of HRV-C were lower in the ICS-treated group compared with those in the ICS-untreated group (p = 0.01), whereas maintenance ICS treatment did not affect the detection rate for viral pathogens in total and HRV-A. Changes in FEV1% predicted in patients treated with systemic corticosteroids for 6-8 days (n = 10; median, 4.90%) were higher than those in patients treated for 3-5 days (n = 8; median, - 10.25%) (p = 0.0085). CONCLUSIONS: Maintenance ICS reduced the detection rates of HRV (mainly HRV-C) in school-age inpatients with asthma exacerbations, and the treatment periods of systemic corticosteroids during exacerbations affected lung function after HRV-induced exacerbations. The protective effects of corticosteroids on virus-induced asthma exacerbations may be dependent upon the types of viral pathogen.

Immune-checkpoint profiles for T cells in bronchoalveolar lavage fluid of patients with immune-checkpoint inhibitor-related interstitial lung disease.

Immune-checkpoint inhibitors (ICIs) have improved clinical outcomes and are becoming a standard treatment for many cancer types. However, these drugs also induce immune-related adverse events, among which interstitial lung disease (ILD) is potentially fatal. The underlying mechanism of ILD induction by ICIs is largely unknown. With the use of flow cytometry, we determined the expression levels of the immune-checkpoint proteins PD-1, TIM-3, TIGIT, LAG-3 and PD-L1 in T cells of bronchoalveolar lavage fluid (BALF) from patients with ICI-related ILD and compared them with those for patients with sarcoidosis or with ILD related to connective tissue disease or cytotoxic drug use. The proportions of CD8+ T cells positive for both PD-1 and TIM-3 or for TIGIT in BALF were significantly higher for ICI-related ILD patients than for those with other types of ILD. A prominent increase in the proportion of PD-1+PD-L1+ cells among CD8+ T cells was also apparent in BALF of a patient with a fatal case of ICI-related ILD, and the proportion of such cells was positively correlated with the grade of ICI-related ILD. Our data reveal the immune-checkpoint profiles of T cells in ICI-related ILD and may provide mechanistic insight into the development of this adverse event.

Early postnatal allergic airway inflammation induces dystrophic microglia leading to excitatory postsynaptic surplus and autism-like behavior.

Microglia play key roles in synaptic pruning, which primarily occurs from the postnatal period to adolescence. Synaptic pruning is essential for normal brain development and its impairment is implicated in neuropsychiatric developmental diseases such as autism spectrum disorders (ASD). Recent epidemiological surveys reported a strong link between ASD and atopic/allergic diseases. However, few studies have experimentally investigated the relationship between allergy and ASD-like manifestations, particularly in the early postnatal period, when allergic disorders occur frequently. Therefore, we aimed to characterize how allergic inflammation in the early postnatal period influences microglia and behavior using mouse models of short- and long-term airway allergy. Male mice were immunized by an intraperitoneal injection of aluminum hydroxide and ovalbumin (OVA) or phosphate-buffered saline (control) on postnatal days (P) 3, 7, and 11, followed by intranasal challenge with OVA or phosphate-buffered saline solution twice a week until P30 or P70. In the hippocampus, Iba-1-positive areas, the size of Iba-1-positive microglial cell bodies, and the ramification index of microglia by Sholl analysis were significantly smaller in the OVA group than in the control group on P30 and P70, although Iba-1-positive microglia numbers did not differ significantly between the two groups. In Iba-1-positive cells, postsynaptic density protein 95 (PSD95)-occupied areas and CD68-occupied areas were significantly decreased on P30 and P70, respectively, in the OVA group compared with the control group. Immunoblotting using hippocampal tissues demonstrated that amounts of PSD95, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor 2, and N-methyl-D-aspartate (NMDA) receptor 2B were significantly increased in the OVA group compared with the control group on P70, and a similar increasing trend for PSD95 was observed on P30. Neurogenesis was not significantly different between the two groups on P30 or P70 by doublecortin immunohistochemistry. The social preference index was significantly lower in the three chamber test and the number of buried marbles was significantly higher in the OVA group than in the control group on P70 but not on P30, whereas locomotion and anxiety were not different between the two groups. Compared with the control group, serum basal corticosterone levels were significantly elevated and hippocampal glucocorticoid receptor (GR) amounts and nuclear GR translocation in microglia, but not in neurons or astrocytes, were significantly decreased in the OVA group on P70 but not on P30. Gene set enrichment analysis of isolated microglia revealed that genes related to immune responses including Toll-like receptor signaling and chemokine signaling pathways, senescence, and glucocorticoid signaling were significantly upregulated in the OVA group compared with the control group on P30 and P70. These findings suggest that early postnatal allergic airway inflammation induces dystrophic microglia that exhibit defective synaptic pruning upon short- and long-term allergen exposure. Furthermore, long-term allergen exposure induced excitatory postsynaptic surplus and ASD-like behavior. Hypothalamo-pituitary-adrenal axis activation and the compensatory downregulation of microglial GR during long-term allergic airway inflammation may also facilitate these changes.

A measuring method for occupancy of immune checkpoint inhibitors in the cell surface.

Monoclonal antibodies, including immune-checkpoint inhibitors, are becoming popular in treatments of many cancers and connective tissue diseases. However, little is known about how long the antibodies combine with antigens on targeted cells or how this duration of binding associates with therapeutic efficacy or potential adverse events. Here, we show the principle and the results of a feasible method for measuring the antibodies' occupancy on the targeted cells using two different detecting antibodies in conjunction with different fluorochromes. Nivolumab occupancy was measured using two detecting antibodies, MIH4 and EH12.2, which are commercially available in vitro (programmed cell death-1 [PD-1] expressing the cell line MIT9 and human T cells) and in T cells from patients treated with nivolumab. Our method has potential for use as a simple and feasible monitoring system in the clinical setting.

Effects of cigarette smoke on barrier function and tight junction proteins in the bronchial epithelium: protective role of cathelicidin LL-37.

BACKGROUND: Airway epithelial barrier function is maintained by the formation of tight junctions (TJs) and adherens junctions (AJs). Inhalation of cigarette smoke causes airway epithelial barrier dysfunction and may contribute to the pathogenesis of chronic lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). We assessed the effects of cigarette smoke on barrier function and expression of multiple TJ and AJ proteins in the bronchial epithelium. We also examined whether treatment with glucocorticosteroids (GCSs), long-acting ß2-agonists (LABAs), and human cathelicidin LL-37 can protect against cigarette smoke extract (CSE)-induced barrier dysfunction. METHODS: Calu-3 cells cultured at the air-liquid interface were pretreated with or without GCSs, LABAs, GCSs plus LABAs, or LL-37, and subsequently exposed to CSE. Barrier function was assessed by transepithelial electronic resistance (TEER) measurements. Gene and protein expression levels of TJ and AJ proteins were analyzed by quantitative PCR and western blotting, respectively. Immunofluorescence staining of TJ and AJ proteins was performed. RESULTS: CSE decreased TEER and increased permeability in a concentration-dependent manner. CSE suppressed gene expression of claudin-1, claudin-3, claudin-4, claudin-7, claudin-15, occludin, E-cadherin, junctional adhesion molecule-A (JAM-A) and zonula occludens-1 (ZO-1) within 12 h post-CSE exposure, while suppressed protein expression levels of occludin at 12 h. CSE-treated cells exhibited discontinuous or attenuated immunostaining for claudin-1, claudin-3, claudin-4, occludin, ZO-1, and E-cadherin compared with untreated cells. GCS treatment partially restored CSE-induced TEER reduction, while LABA treatment had no effect. GCS and LABA combination treatment had no additive effect on CSE-induced TEER reduction and gene suppression of TJ and AJ proteins. Human cathelicidin LL-37 counteracted CSE-induced TEER reduction and prevented disruption of occludin and ZO-1. LL-37 also attenuated CSE-induced decreases in gene and protein expression levels of occludin. CONCLUSIONS: CSE caused airway epithelial barrier dysfunction and simultaneously downregulated multiple TJ and AJ proteins. GCS and LABA combination treatment had no additive effect on CSE-induced TEER reduction. LL-37 counteracted CSE-induced TEER reduction and prevented disruption of occludin and ZO-1. Use of LL-37 to counteract airway epithelial barrier dysfunction may have significant benefits for respiratory diseases such as asthma and COPD.

Interleukin-22 attenuates double-stranded RNA-induced upregulation of PD-L1 in airway epithelial cells via a STAT3-dependent mechanism.

Double-stranded RNA derived from viruses induces host immune responses. PD-L1, also known as B7-H1, is an immune-checkpoint molecule associated with the escape of viruses from host immune systems, which plays a role in the persistence of viral infection, resulting in exacerbations of underlying diseases such as asthma and chronic obstructive pulmonary disease. Interleukin (IL)-22 is produced from various immune cells and has protective properties on mucosal tissue. The binding of IL-22 to IL-22 receptor induces STAT3 activation. We investigated the effect of IL-22 on the expression in airway epithelial cells in vitro and in mouse lungs in vivo after the stimulation with an analog of viral double-stranded RNA, polyinosinic-polycytidylic acid (poly I:C). Stimulation with poly I:C upregulated PD-L1 expression on BEAS-2B cells. This upregulation of PD-L1 was attenuated by IL-22 administration. STAT3 phosphorylation was induced by IL-22 and poly I:C. Treatment of cells with STAT3 siRNA abolished the effect of IL-22 on the poly I:C-induced upregulation of PD-L1. This upregulation of PD-L1 was also attenuated by IL-11, a cytokine inducing STAT3 phosphorylation, in BEAS-2B cells. In mouse lung cells in vivo, IL-22 suppressed poly I:C-induced upregulation of PD-L1. These results suggest that IL-22 attenuates virus-induced upregulation of PD-L1 in airway epithelial cells via a STAT3-dependent mechanism.

Association of Airflow Limitation With Carotid Atherosclerosis in a Japanese Community　- The Hisayama Study.

BACKGROUND: There has been no large-scale observational study examining the association between chronic obstructive pulmonary disease (COPD) or airflow limitation and carotid atherosclerosis in the general population across a wide range of generations in Asia. In the present study we assessed the association between airflow limitation and carotid intima-media thickness (IMT) in a general Japanese population, with consideration of a comprehensive array of cardiovascular risk factors.Methods and Results:In all, 2,099 community-dwelling Japanese subjects were included in the study. Airflow limitation was defined by spirometry. Maximum and mean IMT values were measured using carotid ultrasonography. Among the subjects, 352 (16.8%) had airflow limitation. The geometric mean values of maximum IMT and mean IMT were significantly higher in subjects with than without airflow limitation (1.27 vs. 1.18 mm, respectively, for maximum IMT; 0.73 mm vs. 0.72 mm, respectively, for mean IMT) and increased with the severity of airflow limitation after adjustment for conventional risk factors, including smoking habits and serum high-sensitivity C-reactive protein. It should be noted that the magnitude of these associations was greater in the middle-aged (40-64 years) than elderly (≥65 years) subgroup. CONCLUSIONS: The findings of the present study suggest that airflow limitation is a significant risk factor for carotid atherosclerosis, especially in midlife, in the general Japanese population.

Prevalence of Airflow Limitation Defined by Pre- and Post-Bronchodilator Spirometry in a Community-Based Health Checkup: The Hisayama Study.

Spirometry in health checkup may contribute to early diagnosis of chronic obstructive pulmonary disease (COPD) and asthma. Although post-bronchodilator airflow limitation is essential for definite diagnosis of COPD and post-bronchodilator normalization of airflow is suggestive of asthma, this test has not been prevailed in health checkup. The objective of this study was to estimate the prevalence of airflow limitation defined by pre- and post-bronchodilator spirometry in health checkup. Post-bronchodilator spirometry was conducted for participants with airflow limitation in a town-wide health checkup for residents aged 40 years and older in Hisayama, a town in the western part of Japan. The prevalence of pre- and post-bronchodilator airway limitation defined by FEV1/FVC < 70% were estimated. A total of 2,232 participants underwent pre-bronchodilator spirometry. In males, the age of current smokers was significantly younger than those of never smokers and former smokers. In females, the ages of current- and former smokers were significantly younger than never smokers. The values of %FEV1 and %FVC in current smokers were significantly lower than those in former smokers and never smokers. Two hundred sixty nine subjects, 85% of total subjects with a pre-bronchodilator FEV1/FVC < 70%, completed post-bronchodilator spirometry. The prevalence of pre-bronchodilator airflow limitation was 14.6% in males and 13.7% in females, and the prevalence of post-bronchodilator airway limitation was 8.7% and 8.7%, respectively. Post-bronchodilator spirometry in health checkup would reduce the number of subjects with probable COPD to two-third. Recommendation for those examinees to take further evaluations may pave the way for early intervention.

Validation of a COPD screening questionnaire and establishment of diagnostic cut-points in a Japanese general population: the Hisayama study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is highly prevalent worldwide. COPD is a treatable disease and it is important to identify COPD subjects, highlighting the need for an efficient screening measure. Although the COPD screening questionnaire (COPD Population Screener, COPD-PS) was developed as a screening tool, its validity is not clear in population-based studies. This study determines the validity of the COPD-PS in the general Japanese population. METHODS: All registered residents living in the town of Hisayama aged above 40 were solicited to participate in a health check-up in 2012. All subjects aged 40-79 without physician-diagnosed asthma or lung resection were recruited, and 2357 subjects with the COPD-PS recorded and valid spirometry measurements were analyzed. Persistent airflow obstruction (AO) was defined by post-bronchodilator FEV1/FVC < 0.7. The sensitivity and specificity of the COPD-PS score for identifying AO was assessed by logistic regression analysis. RESULTS: The prevalence of AO in this population was 6.5%. The overall area under the receiver operating characteristic (ROC) curve for the continuous COPD-PS score was 0.748. A cut-point of 4-points is recommended, resulting in a sensitivity of 67.1% and specificity of 72.9% with an area under the ROC curve of 0.70. The positive predictive value was 14.6% and negative predictive value was 97.0%. CONCLUSIONS: The COPD-PS appears to be an adequate measure for large scale screening of possible airflow obstruction requiring further testing with spirometry.

Small interfering RNA against CD86 during allergen challenge blocks experimental allergic asthma.

BACKGROUND: CD86-CD28 interaction has been suggested as the principal costimulatory pathway for the activation and differentiation of naïve T cells in allergic inflammation. However, it remains uncertain whether this pathway also has an essential role in the effector phase. We sought to determine the contribution of CD86 on dendritic cells in the reactivation of allergen-specific Th2 cells. METHODS: We investigated the effects of the downregulation of CD86 by short interfering RNAs (siRNAs) on Th2 cytokine production in the effector phase in vitro and on asthma phenotypes in ovalbumin (OVA)-sensitized and -challenged mice. RESULTS: Treatment of bone marrow-derived dendritic cells (BMDCs) with CD86 siRNA attenuated LPS-induced upregulation of CD86. CD86 siRNA treatment impaired BMDCs' ability to activate OVA-specific Th2 cells. Intratracheal administration of CD86 siRNA during OVA challenge downregulated CD86 expression in the airway mucosa. CD86 siRNA treatment ameliorated OVA-induced airway eosinophilia, airway hyperresponsiveness, and the elevations of OVA-specific IgE in the sera and IL-5, IL-13, and CCL17 in the bronchoalveolar lavage fluid, but not the goblet cell hyperplasia. CONCLUSION: These results suggest that local administration of CD86 siRNA during the effector phase ameliorates lines of asthma phenotypes. Targeting airway dendritic cells with siRNA suppresses airway inflammation and hyperresponsiveness in an experimental model of allergic asthma.

Cigarette smoke impairs phagocytosis of apoptotic neutrophils by alveolar macrophages via inhibition of the histone deacetylase/Rac/CD9 pathways.

Efferocytosis, which is the homeostatic phagocytosis of apoptotic cells, prevents the release of toxic intracellular contents and subsequent tissue damage. Impairment of efferocytosis was reported in alveolar macrophages (AMs) of patients with chronic obstructive pulmonary disease (COPD), a common disease caused by smoking. In COPD, histone deacetylase (HDAC) activity is reduced in AMs. We investigated whether the reduction of HDAC activity is associated with the impairment of efferocytosis. Murine AMs were collected by bronchoalveolar lavage and their ability to efferocytose apoptotic human polymorphonuclear leukocytes was assessed. Pre-treatment of AMs with cigarette smoke extract (CSE) or trichostatin A (TSA), an HDAC inhibitor, suppressed efferocytosis and CSE reduced HDAC activity. TSA inhibited the activity of Rac, a key mediator of efferocytosis. These TSA-induced impairments were restored by treatment of AMs with aminophylline, a potent activator of HDAC. To further elucidate the underlying mechanism, we explored a role of CD9 in TSA-induced impairment of efferocytosis. CD9 is a transmembrane protein of the tetraspanin family that facilitates the uptake of several pathogens and other material. TSA profoundly down-regulated the expression of CD9 on AMs. The expression of CD9 was partly down-regulated by the Rac inhibitor. Pretreatment with an anti-CD9 mAb or CD9 small interfering RNA inhibited efferocytosis, which was attributable to the reduced binding of AMs to apoptotic cells. These results suggest that smoking impairs efferocytosis via inhibition of HDAC/Rac/CD9 pathways. Aminophylline/theophylline is effective in restoring the impairment of efferocytosis and might have benefit for the treatment of patients with COPD.

Leukotriene B4 receptor BLT2 negatively regulates allergic airway eosinophilia.

Leukotriene B4 (LTB4) has been implicated in the pathogenesis of allergic diseases. BLT2, a low-affinity LTB4 receptor, is activated by LTB4 and 12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid (12-HHT). Although the high-affinity LTB4 receptor BLT1 has been shown to exert proinflammatory roles, the role of BLT2 in allergic inflammation has not been clarified. To study the function of BLT2 in development of asthma, we used mice model of ovalbumin (OVA)-induced allergic airway disease. The 12-HHT levels were elevated in bronchoalveolar lavage (BAL) fluids of OVA-sensitized/challenged wild-type mice. BLT2-deficient mice exhibited enhanced eosinophilia in BAL fluids after OVA exposure. Interleukin (IL)-13 levels in BAL fluids and IL-13-producing CD4(+) T cells in the lungs were elevated in BLT2-deficient mice compared to wild-type mice, whereas the levels of IL-4, IL-5, and interferon (IFN)-γ in BAL fluids and serum OVA-specific IgE were comparable. Transfection of BLT2-specific small interfering RNA enhanced IL-13 production in CD4(+) T cells in vitro. Expression of BLT2 mRNA in CD4(+) T cells was significantly reduced in patients with asthma compared to healthy control subjects. These findings indicate that BLT2 has a protective role in allergic airway inflammation and that diminished BLT2 expression in CD4(+) T cells may contribute to the pathophysiology of asthma.

PI3K-delta mediates double-stranded RNA-induced upregulation of B7-H1 in BEAS-2B airway epithelial cells.

Airway viral infection disturbs the health-related quality of life. B7-H1 (also known as PD-L1) is a coinhibitory molecule associated with the escape of viruses from the mucosal immunity, leading to persistent infection. Most respiratory viruses generate double-stranded (ds) RNA during replication. The stimulation of cultured airway epithelial cells with an analog of viral dsRNA, polyinosinic-polycytidylic acid (poly IC) upregulates the expression of B7-H1 via activation of the nuclear factor κB(NF-κB). The mechanism of upregulation was investigated in association with phosphatidylinositol 3-kinases (PI3Ks). Poly IC-induced upregulation of B7-H1 was profoundly suppressed by a pan-PI3K inhibitor and partially by an inhibitor or a small interfering (si)RNA for PI3Kδ in BEAS-2B cells. Similar results were observed in the respiratory syncytial virus-infected cells. The expression of p110δ was detected by Western blot and suppressed by pretreatment with PI3Kδ siRNA. The activation of PI3Kδ is typically induced by oxidative stress. The generation of reactive oxygen species was increased by poly IC. Poly IC-induced upregulation of B7-H1 was attenuated by N-acetyl-L-cysteine, an antioxidant, or by oxypurinol, an inhibitor of xanthine oxidase. Poly IC-induced activation of NF-κB was suppressed by a pan-PI3K inhibitor but not by a PI3Kδ inhibitor. These results suggest that PI3Kδ mediates dsRNA-induced upregulation of B7-H1 without affecting the activation of NF-κB.

Mast cells contribute to double-stranded RNA-induced augmentation of airway eosinophilia in a murine model of asthma.

BACKGROUND: Clinical studies showed the contribution of viral infection to the development of asthma. Although mast cells have multiple roles in the pathogenesis of allergic asthma, their role of in the virus-associated pathogenesis of asthma remains unknown. Most respiratory viruses generate double-stranded (ds) RNA during their replication. dsRNA provokes innate immune responses. We recently showed that an administration of polyinocinic polycytidilic acid (poly IC), a mimetic of viral dsRNA, during allergen sensitization augments airway eosinophilia and hyperresponsiveness in mice via enhanced production of IL-13. METHODS: The effect of poly IC on allergen-induced airway eosinophilia was investigated for mast cell-conserved Kit+/+ mice and -deficient KitW/KitW-v mice. The outcome of mast cell reconstitution was further investigated. RESULTS: Airway eosinophilia and IL-13 production were augmented by poly IC in Kit+/+ mice but not in KitW/KitW-v mice. When KitW/KitW-v mice were reconstituted with bone marrow-derived mast cells (BMMCs), the augmentation was restored. The augmentation was not induced in the mice systemically deficient for TIR domain-containing adaptor-inducing IFN-ß (TRIF) or interferon regulatory factor (IRF)-3, both mediate dsRNA-triggered innate immune responses. The augmentation was, however, restored in KitW/KitW-v mice reconstituted with TRIF-deficient or IRF-3-deficient BMMCs. Although leukotriene B4 and prostaglandin D2 are major lipid mediators released from activated mast cells, no their contribution was shown to the dsRNA-induced augmentation of airway eosinophilia. CONCLUSIONS: We conclude that mast cells contribute to dsRNA-induced augmentation of allergic airway inflammation without requiring direct activation of mast cells with dsRNA or involvement of leukotriene B4 or prostaglandin D2.

Effects of tiotropium on lung function in severe asthmatics with or without emphysematous changes.

The effects of tiotropium, an inhaled long-acting anti-cholinergic agent, on lung function were investigated in obstructed severe asthmatics with and without emphysematous changes despite maximal recommended treatments with high-dose of inhaled glucocorticoids and inhaled long-acting ß(2)-agonists. We conducted a double-blind, placebo-controlled study of an inhaled single-dose of tiotropium in 18 asthmatics with emphysema and 18 without emphysema in a crossover manner. The primary efficacy outcome was the relative change in forced expiratory volume in 1 s (FEV(1)) from baseline to 60 min, and the secondary outcome was a relative change in FEV(1) from baseline to 12 h. Subsequently, the patients were treated with tiotropium inhaled once daily for 12 weeks in an open label manner, and lung function and symptoms were evaluated. At baseline, patients with or without emphysema had a mean FEV(1) of 55.9% before tiotropium and 56.8% before placebo, or 77.4% before tiotropium and 77.6% before placebo of the predicted value and were taking a mean dose of inhaled glucocorticoids of 1444 or 1422 µg/day. Among patients with emphysema, the increase from baseline FEV(1) was 12.6 percentage points higher at 60 min after tiotropium than after placebo. Among patients without emphysema, the increase from baseline FEV(1) was 5.4 percentage points higher at 60 min after tiotropium than after placebo. Tiotropium resulted in improved lung function and symptoms in asthmatics with and without emphysema. These findings suggest that tiotropium will provide a new strategy for the treatment of bronchial asthma and of overlapping asthma and COPD.

Computational fluid-particle dynamics modeling of ultrafine to coarse particles deposition in the human respiratory system, down to the terminal bronchiole.

BACKGROUND AND OBJECTIVES: Suspended respirable airborne particles are associated with human health risks and especially particles within the range of ultrafine (< 0.1 µm) or fine (< 2.5 µm) have a high possibility of penetrating the lung region, which is concerned to be closely related to the bronchial or alveoli tissue dosimetry. Nature complex structure of the respiratory system requires much effort to explore and comprehend the flow and the inhaled particle dynamics for precise health risk assessment. Therefore, this study applied the computational fluid-particle dynamics (CFPD) method to elucidate the deposition characteristics of ultrafine-to-coarse particles in the human respiratory tract from nostrils to the 16th generation of terminal bronchi. METHODS: The realistic bronchi up to the 8th generation are precisely and perfectly generated from computed tomography (CT) images, and an artificial model compensates for the 9th-16th bronchioles. Herein, the steady airflow is simulated at constant breathing flow rates of 7.5, 15, and 30 L/min, reproducing human resting-intense activity. Then, trajectories of the particle size ranging from 0.002 - 10 µm are tracked using a discrete phase model. RESULTS: Here, we report reliable results of airflow patterns and particle deposition efficiency in the human respiratory system validated against experimental data. The individual-related focal point of ultrafine and fine particles deposition rates was actualized at the 8th generation; whilst the hot-spot of the deposited coarse particles was found in the 6th generation. Lobar deposition characterizes the dominance of coarse particles deposited in the right lower lobe, whereas the left upper-lower and right lower lobes simultaneously occupy high deposition rates for ultrafine particles. Finally, the results indicate a higher deposition in the right lung compared to its counterpart. CONCLUSIONS: From the results, the developed realistic human respiratory system down to the terminal bronchiole in this study, in coupling with the CFPD method, delivers the accurate prediction of a wide range of particles in terms of particle dosimetry and visualization of site-specific in the consecutive respiratory system. In addition, the series of CFPD analyses and their results are to offer in-depth information on particle behavior in human bronchioles, which may benefit health risk assessment or drug delivery studies.