Endothelin-1-mediated Brainstem Glial Activation Produces Asthmatic Airway Vagal Hypertonia Via Enhanced ATP-P2X4 Receptor Signaling in Sprague-Dawley Rats.

The occurrence of major asthma symptoms is largely attributed to airway vagal hypertonia, of which the central mechanisms remain unclear. This study tests the hypotheses that endothelin-1-mediated brainstem glial activation produces asthmatic airway vagal hypertonia via enhanced action of adenosine 5'-triphosphate on neuronal purinergic P2X4 receptors. A rat model of asthma was prepared using ovalbumin. Airway vagal tone was evaluated by the recurrent laryngeal discharge and plethysmographic measurement of pulmonary function. The changes in the brainstem were examined using ELISA, Western blot, luciferin-luciferase, quantitative reverse transcription-polymerase chain reaction, enzyme activity assay and immunofluorescent staining, respectively. The results showed that in the medulla of rats, endothelin receptor type B and P2X4 receptors were primarily expressed in astrocytes and neurons, respectively, and both of which, along with endothelin-1 content, were significantly increased after ovalbumin sensitization. Ovalbumin sensitization significantly increased recurrent laryngeal discharge, which was blocked by acute intracisternal injection of P2X4 receptor antagonist 5-BDBD, knockdown of brainstem P2X4 receptors, and chronic intraperitoneal injection of endothelin receptor type B antagonist BQ788, respectively. Ovalbumin sensitization activated microglia and astrocytes and significantly decreased ecto-5'-nucleotidase activity in the medulla, and all of which, together with the increase of medullary P2X4 receptor expression and decrease of pulmonary function, were reversed by chronic BQ788 treatment. These results demonstrated that in rats, allergic airway challenge activates both microglia and astrocytes in the medulla via enhanced endothelin-1/endothelin receptor type B signaling, which subsequently causes airway vagal hypertonia via augmented adenosine 5'-triphosphate/P2X4 receptor signaling in central neurons of airway vagal reflex.

Wogonoside Ameliorates Airway Inflammation and Mucus Hypersecretion via NF-κB/STAT6 Signaling in Ovalbumin-Induced Murine Acute Asthma.

Asthma is recognized as a chronic respiratory illness characterized by airway inflammation and airway hyperresponsiveness. Wogonoside, a flavonoid glycoside, is reported to significantly alleviate the inflammation response and oxidative stress. Herein, this study aimed to investigate the therapeutic effect and underlying mechanism of wogonoside on airway inflammation and mucus hypersecretion in a murine asthma model and in human bronchial epithelial cells (16HBE). BALB/c mice were sensitized and challenged with ovalbumin (OVA). Pulmonary function and the number of cells in the bronchoalveolar lavage fluid (BALF) were examined. Pathological changes in lung tissue in each group were evaluated via hematoxylin and eosin and periodic acid-Schiff staining, and changes in levels of cytokines in BALF and of immunoglobulin E in serum were determined via an enzyme-linked immunosorbent assay. The expression of relevant genes in lung tissue was analyzed via real-time PCR. Western blotting and immunofluorescence were employed to detect the expression of relevant proteins in lung tissue and 16HBE cells. Treatment with 10 and 20 mg/kg wogonoside significantly attenuated the OVA-induced increase of inflammatory cell infiltration, mucus secretion, and goblet cell percentage and improved pulmonary function. Wogonoside treatment reduced the level of T-helper 2 cytokines including interleukin (IL)-4, IL-5, and IL-13 in BALF and of IgE in serum and decreased the mRNA levels of cytokines (IL-4, IL-5, IL-6, IL-13, and IL-1ß and tumor necrosis factor-α), chemokines (CCL-2, CCL-11, and CCL-24), and mucoproteins (MUC5AC, MUC5B, and GOB5) in lung tissues. The expression of MUC5AC and the phosphorylation of STAT6 and NF-κB p65 in lung tissues and 16HBE cells were significantly downregulated after wogonoside treatment. Thus, wogonoside treatment may effectively decrease airway inflammation, airway remodeling, and mucus hypersecretion via blocking NF-κB/STAT6 activation.

Antibiotic exposure during pregnancy increases risk for childhood atopic diseases: a nationwide cohort study.

PURPOSE: The prevalence of atopic diseases has increased in recent decades. A possible link between antibiotic use during pregnancy and childhood atopic disease has been proposed. The aim of this study is to explore the association of antibiotic exposure during pregnancy with childhood atopic diseases from a nationwide, population-based perspective. METHODS: This was a nationwide population-based cohort study. Taiwan's National Health Insurance Research Database was the main source of data. The pairing of mothers and children was achieved by linking the NHIRD with the Taiwan Maternal and Child Health Database. This study enrolled the first-time pregnancies from 2004 to 2010. Infants of multiple delivery, preterm delivery, and death before 5 years old were excluded. All participants were followed up at least for 5 years. Antenatal antibiotics prescribed to mothers during the pregnancy period were reviewed. Children with more than two outpatient visits, or one admission, with a main diagnosis of asthma, allergic rhinitis, or atopic dermatitis were regarded as having an atopic disease. RESULTS: A total of 900,584 children were enrolled in this study. The adjusted hazard ratios of antibiotic exposure during pregnancy to childhood atopic diseases were 1.12 for atopic dermatitis, 1.06 for asthma, and 1.08 for allergic rhinitis, all of which reached statistical significance. The trimester effect was not significant. There was a trend showing the higher the number of times a child was prenatally exposed to antibiotics, the higher the hazard ratio was for childhood atopic diseases. CONCLUSIONS: Prenatal antibiotic exposure might increase the risk of childhood atopic diseases in a dose-dependent manner.

Benralizumab in children with severe eosinophilic asthma: Pharmacokinetics and long-term safety (TATE study).

BACKGROUND: Benralizumab is an anti-interleukin-5 receptor α monoclonal antibody approved as an add-on maintenance treatment for patients with uncontrolled severe asthma. Prior Phase 3 studies have evaluated benralizumab in patients aged ≥12 years with severe uncontrolled asthma. The TATE study evaluated the pharmacokinetics (PK), pharmacodynamics (PD), and safety of benralizumab treatment in children. METHODS: TATE was an open-label, Phase 3 study of benralizumab in children aged 6-11 years from the United States and Japan (plus participants aged 12-14 years from Japan) with severe eosinophilic asthma. Participants received benralizumab 10/30 mg according to weight (<35/≥35 kg). Primary endpoints included maximum serum concentration (Cmax ), clearance, half-life (t1/2 ), and blood eosinophil count. Clearance and t1/2 were derived from a population PK (popPK) analysis. Safety and tolerability were also assessed. RESULTS: Twenty-eight children aged 6-11 years were included, with an additional two participants from Japan aged 12-14 years also included in the popPK analysis. Mean Cmax was 1901.2 and 3118.7 ng/mL in the 10 mg/<35 kg and 30 mg/≥35 kg groups, respectively. Clearance was 0.257, and mean t1/2 was 14.5 days. Near-complete depletion of blood eosinophils was shown across dose/weight groups. Exploratory efficacy analyses found numerical improvements in mean FEV1 , mean ACQ-IA, patient/clinician global impression of change, and exacerbation rates. Adverse events occurred in 22/28 (78.6%) of participants; none led to discontinuation/death. CONCLUSION: PK, PD, and safety data support long-term benralizumab in children with severe eosinophilic asthma, and were similar to findings in adolescents and adults. TRIAL REGISTRATION: ClinicalTrials.gov-ID: NCT04305405.

Prenatal polycyclic aromatic hydrocarbon exposure and asthma at age 8-9 years in a multi-site longitudinal study.

BACKGROUND AND AIM: Studies suggest prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) may influence wheezing or asthma in preschool-aged children. However, the impact of prenatal PAH exposure on asthma and wheeze in middle childhood remain unclear. We investigated these associations in socio-demographically diverse participants from the ECHO PATHWAYS multi-cohort consortium. METHODS: We included 1,081 birth parent-child dyads across five U.S. cities. Maternal urinary mono-hydroxylated PAH metabolite concentrations (OH-PAH) were measured during mid-pregnancy. Asthma at age 8-9 years and wheezing trajectory across childhood were characterized by caregiver reported asthma diagnosis and asthma/wheeze symptoms. We used logistic and multinomial regression to estimate odds ratios of asthma and childhood wheezing trajectories associated with five individual OH-PAHs, adjusting for urine specific gravity, various maternal and child characteristics, study site, prenatal and postnatal smoke exposure, and birth year and season in single metabolite and mutually adjusted models. We used multiplicative interaction terms to evaluate effect modification by child sex and explored OH-PAH mixture effects through Weighted Quantile Sum regression. RESULTS: The prevalence of asthma in the study population was 10%. We found limited evidence of adverse associations between pregnancy OH-PAH concentrations and asthma or wheezing trajectories. We observed adverse associations between 1/9-hydroxyphenanthrene and asthma and persistent wheeze among girls, and evidence of inverse associations with asthma for 1-hydroxynathpthalene, which was stronger among boys, though tests for effect modification by child sex were not statistically significant. CONCLUSIONS: In a large, multi-site cohort, we did not find strong evidence of an association between prenatal exposure to PAHs and child asthma at age 8-9 years, though some adverse associations were observed among girls.

Medium-term exposure to size-fractioned particulate matter and asthma exacerbations in China: A longitudinal study of asthmatics with poor medication adherence.

BACKGROUND: Studies have shown that short- and long-term exposure to particulate matter (PM) can increase the risk of asthma morbidity and mortality. However, the effect of medium-term exposure remains unknown. We aim to examine the effect of medium-term exposure to size-fractioned PM on asthma exacerbations among asthmatics with poor medication adherence. METHODS: We conducted a longitudinal study in China based on the National Mobile Asthma Management System Project that specifically and routinely followed asthma exacerbations in asthmatics with poor medication adherence from April 2017 to May 2019. High-resolution satellite remote-sensing data were used to estimate each participant's medium-term exposure (on average 90 days) to size-fractioned PM (PM1, PM2.5, and PM10) based on the residential address and the date of the follow-up when asthma exacerbations (e.g., hospitalizations and emergency room visits) occurred or the end of the follow-up. The Cox proportional hazards model was employed to examine the hazard ratio of asthma exacerbations associated with each PM after controlling for sex, age, BMI, education level, geographic region, and temperature. RESULTS: Modelling results revealed nonlinear exposure-response associations of asthma exacerbations with medium-term exposure to PM1, PM2.5, and PM10. Specifically, for emergency room visits, we found an increased hazard ratio for PM1 above 22.8 µg/m3 (1.060, 95 % CI: 1.025-1.096, per 1 µg/m3 increase), PM2.5 above 38.2 µg/m3 (1.032, 95 % CI: 1.010-1.054), and PM10 above 78.6 µg/m3 (1.019, 95 % CI: 1.006-1.032). For hospitalizations, we also found an increased hazard ratio for PM1 above 20.3 µg/m3 (1.055, 95 % CI: 1.001-1.111) and PM2.5 above 39.2 µg/m3 (1.038, 95 % CI: 1.003-1.074). Furthermore, the effects of PM were greater for a longer exposure window (90-180 days) and among participants with a high BMI. CONCLUSION: This study suggests that medium-term exposure to PM is associated with an increased risk of asthma exacerbations in asthmatics with poor medication adherence, with a higher risk from smaller PM.

Lung Gene Expression Suggests Roles for Interferon-Stimulated Genes and Adenosine Deaminase Acting against RNA-1 in Pathologic Responses to Diisocyanate.

Mechanisms underlying methylene diphenyl diisocyanate (MDI) and other low molecular weight chemical-induced asthma are unclear and appear distinct from those of high molecular weight (HMW) allergen-induced asthma. We sought to elucidate molecular pathways that differentiate asthma-like pathogenic vs nonpathogenic responses to respiratory tract MDI exposure in a murine model. Lung gene expression differences in MDI exposed immune-sensitized and nonsensitized mice vs unexposed controls were measured by microarrays, and associated molecular pathways were identified through bioinformatic analyses and further compared with published studies of a prototypic HMW asthmagen (ovalbumin). Respiratory tract MDI exposure significantly altered lung gene expression in both nonsensitized and immune-sensitized mice, vs controls. Fifty-three gene transcripts were altered in all MDI exposed lung tissue vs controls, with levels up to 10-fold higher in immune-sensitized vs nonsensitized mice. Gene transcripts selectively increased in MDI exposed immune-sensitized animals were dominated by chitinases and chemokines and showed substantial overlap with those increased in ovalbumin-induced asthma. In contrast, MDI exposure of nonsensitized mice increased type I interferon stimulated genes (ISGs) in a pattern reflecting deficiency in adenosine deaminase acting against RNA (ADAR-1), an important regulator of innate, as well as "sterile" or autoimmunity triggered by tissue damage. Thus, MDI-induced changes in lung gene expression were identified that differentiate nonpathogenic innate responses in nonsensitized hosts from pathologic adaptive responses in immune-sensitized hosts. The data suggest that MDI alters unique biological pathways involving ISGs and ADAR-1, potentially explaining its unique immunogenicity/allergenicity.

Increased di-(2-ethylhexyl) phthalate exposure poses a differential risk for adult asthma clusters.

BACKGROUND: DEHP, a common plasticizer known for its hormone-disrupting properties, has been associated with asthma. However, a significant proportion of adult asthma cases are "non-atopic", lacking a clear etiology. METHODS: In a case-control study conducted between 2011 and 2015, 365 individuals with current asthma and 235 healthy controls from Kaohsiung City were enrolled. The control group comprised individuals without asthma, Type 2 Diabetes Mellitus (T2DM), hypertension, or other respiratory/allergic conditions. The study leveraged asthma clusters (Clusters A to F) established in a prior investigation. Analysis involved the examination of urinary DEHP metabolites (MEHP and MEHHP), along with the assessment of oxidative stress, sphingolipid metabolites, and inflammatory biomarkers. Statistical analyses encompassed Spearman's rank correlation coefficients, multiple logistic regression, and multinomial logistic regression. RESULTS: Asthma clusters (E, D, C, F, A) exhibited significantly higher ORs of MEHHP exposures compared to the control group. When considering asthma-related comorbidities (T2DM, hypertension, or both), patients without comorbidities demonstrated significantly higher ORs of the sum of primary and secondary metabolites (MEHP + MEHHP) and MEHHP compared to those with asthma comorbidities. A consistent positive correlation between urinary HEL and DEHP metabolites was observed, but a consistent negative correlation between DEHP metabolites and selected cytokines was identified. CONCLUSION: The current study reveals a heightened risk of MEHHP and MEHP + MEHHP exposure in specific asthma subgroups, emphasizing its complex relationship with asthma. The observed negative correlation with cytokines suggests a new avenue for research, warranting robust evidence from epidemiological and animal studies.

The effects of vitamin D supplementation on inflammatory biomarkers in patients with asthma: a systematic review and meta-analysis of randomized controlled trials.

Background: While the association between vitamin D and several inflammatory biomarkers in asthma patients has been extensively reported, it remains unclear whether supplementation modifies these biomarkers. This review aims to evaluate the impact of vitamin D supplementation on inflammatory biomarkers measured in vivo in individuals with asthma. Methods: We conducted a systematic review of randomized controlled trials (RCTs) published until November 2022 in six electronic databases evaluating the impact of vitamin D supplementation (any dose, form, administration route, frequency, or duration) compared to placebo in children or adults. The two co-primary outcomes were serum IgE and blood eosinophils reported at the endpoint. Secondary outcomes included other markers of type 2 inflammation (e.g., sputum eosinophils, fractional exhaled nitric oxide, etc.), anti-inflammatory biomarkers (e.g., interleukin (IL)-10, etc.), markers of non-type 2 inflammation (e.g., high-sensitivity C-reactive protein, etc.), and non-specific biomarkers (e.g., macrophages, etc.). Data were aggregated using fixed or random effect models. Results: Thirteen RCTs (5 in adults, 5 in pediatric patients, and 3 in mixed age groups) testing doses of vitamin D supplementation ranging from 800 to 400,000 IU over periods of 6 weeks to 12 months were included. Eight studies provided data on serum IgE and four on blood eosinophils. As secondary outcomes, three studies reported on sputum eosinophils, four on FeNO, five on serum IL-10, and two on airway IL-10. Compared to placebo, vitamin D supplementation had no significant effect on serum IgE (Mean difference [MD] [95% CI]: 0.06 [-0.13, 0.26] IU/mL), blood eosinophils (MD [95% CI]: - 0.02 [-0.11, 0.07] 103/µL), or FeNO (MD [95% CI]: -4.10 [-10.95, 2.75] ppb) at the endpoint. However, the vitamin D supplementation group showed higher serum IL-10 levels compared to placebo (MD [95% CI]: 18.85 [1.11, 36.59] pg/ml) at the endpoint. Although data could not be aggregated, narrative synthesis suggested no significant effect of supplementation on sputum eosinophils and IL-10 in both sputum and exhaled breath condensate, at the endpoint. Conclusion: Vitamin D supplementation in individuals with asthma was not associated with lower inflammatory biomarkers related to type 2 inflammation. However, it was significantly associated with higher serum IL-10 compared to placebo. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022365666.

Dexamethasone protects against asthma via regulating Hif-1α-glycolysis-lactate axis and protein lactylation.

PURPOSE: Asthma can not be eradicated till now and its control primarily relies on the application of corticosteroids. Recently, glycolytic reprogramming has been reportedly contributed to asthma, this study aimed to reveal whether the effect of corticosteroids on asthma control is related to their regulation of glycolysis and glycolysis-dependent protein lactylation. METHODS: Ovalbumin (OVA) aeroallergen was used to challenge mice and stimulate human macrophage cell line THP-1 following dexamethasone (DEX) treatment. Airway hyperresponsiveness, airway inflammation, the expressions of key glycolytic enzymes and pyroptosis markers, the level of lactic acid, real-time glycolysis and oxidative phosphorylation (OXPHOS), and protein lactylation were analyzed. RESULTS: DEX significantly attenuated OVA-induced eosinophilic airway inflammation, including airway hyperresponsiveness, leukocyte infiltration, goblet cell hyperplasia, Th2 cytokines production and pyroptosis markers expression. Meanwhile, OVA-induced Hif-1α-glycolysis axis was substantially downregulated by DEX, which resulted in low level of lactic acid. Besides, key glycolytic enzymes in the lungs of asthmatic mice were notably co-localized with F4/80-positive macrophages, indicating metabolic shift to glycolysis in lung macrophages during asthma. This was confirmed in OVA-stimulated THP-1 cells that DEX treatment resulted in reductions in pyroptosis, glycolysis and lactic acid level. Finally, protein lactylation was found significantly increased in the lungs of asthmatic mice and OVA-stimulated THP-1 cells, which were both inhibited by DEX. CONCLUSION: Our present study revealed that the effect of DEX on asthma control was associated with its suppressing of Hif-1α-glycolysis-lactateaxis and subsequent protein lactylation, which may open new avenues for the therapy of eosinophilic asthma.

Associations of prenatal ambient air pollution exposures with asthma in middle childhood.

We examined associations between prenatal fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3) exposures and child respiratory outcomes through age 8-9 years in 1279 ECHO-PATHWAYS Consortium mother-child dyads. We averaged spatiotemporally modeled air pollutant exposures during four fetal lung development phases: pseudoglandular (5-16 weeks), canalicular (16-24 weeks), saccular (24-36 weeks), and alveolar (36+ weeks). We estimated adjusted relative risks (RR) for current asthma at age 8-9 and asthma with recent exacerbation or atopic disease, and odds ratios (OR) for wheezing trajectories using modified Poisson and multinomial logistic regression, respectively. Effect modification by child sex, maternal asthma, and prenatal environmental tobacco smoke was explored. Across all outcomes, 95% confidence intervals (CI) included the null for all estimates of associations between prenatal air pollution exposures and respiratory outcomes. Pseudoglandular PM2.5 exposure modestly increased risk of current asthma (RRadj = 1.15, 95% CI: 0.88-1.51); canalicular PM2.5 exposure modestly increased risk of asthma with recent exacerbation (RRadj = 1.26, 95% CI: 0.86-1.86) and persistent wheezing (ORadj = 1.28, 95% CI: 0.86-1.89). Similar findings were observed for O3, but not NO2, and associations were strengthened among mothers without asthma. While not statistically distinguishable from the null, trends in effect estimates suggest some adverse associations of early pregnancy air pollution exposures with child respiratory conditions, warranting confirmation in larger samples.

Anti-inflammation of LZTFL1 knockdown in OVA-induced asthmatic mice: Through ERK/GATA3 signaling pathway.

Asthma is a common chronic respiratory disease characterized by Th2-type inflammation in the airways. Leucine zip transcription factor-like 1 (LZTFL1) has been implicated in the regulation of Th2-related factors. The knockdown of LZTFL1 resulted in decreased levels of IL-4, IL-5, and IL-13. We hypothesize that LZTFL1 may have an effect on asthma. We established an acute asthmatic mouse model using the Ovalbumin (OVA) sensitization, and we found that LZTFL1 expression was upregulated in OVA-induced CD4 + T cells. Mice challenged with OVA were administered 5 × 107 TU of lentivirus via tail vein injection. LZTFL1 knockdown reversed the frequency of sneezing and nose rubbing in OVA mice. LZTFL1 knockdown reduced inflammatory cell infiltration, reduced goblet cell numbers, and mitigated collagen deposition in lung tissue. LZTFL1 knockdown decreased the levels of OVA-specific IgE, IL-4, IL-5, and IL-13 in alveolar lavage fluid of asthmatic mice. Furthermore, LZTFL1 knockdown inhibited the aberrant activation of MEK/ERK signaling pathway in asthmatic mice. GATA binding protein 3 (GATA3) is an essential transcription factor in Th2 differentiation. Flow cytometry results revealed that LZTFL1 knockdown reduced the number of GATA3 + CD4 + Th2 cells, while it did not affect the stability of GATA3 mRNA. This may be attributed to ERK signaling which stabilized GATA3 by preventing its ubiquitination and subsequent degradation. In conclusion, LZTFL1 knockdown attenuates inflammation and pathological changes in OVA-induced asthmatic mice through ERK/GATA3 signaling pathway.

E-cigarettes exacerbate allergic inflammation via cytokine induction and MUC5AC/5B expression in a murine asthma model.

The effects of electronic cigarettes (e-cigarettes) vapor on inflammation and mucin secretion on asthmatics remain insufficiently explored. This study investigated the effects of e-cigarette vapor on allergic inflammation, cytokine production, and MUC5AC/5B expression in murine asthma model. Airway hyperresponsiveness was significantly higher in the e-cigarette-exposed ovalbumin (OVA) sensitization group than in the control, e-cigarette exposure, and OVA sensitization groups. The e-cigarette-exposed OVA sensitization group showed significantly greater infiltration of inflammatory cells and Th2-mediated inflammatory cytokines (interleukin-4 and -5) compared to the control, e-cigarette exposure, and OVA sensitization groups. MUC5AC mucin levels were significantly elevated in the e-cigarette exposure, OVA sensitization, and e-cigarette-exposed OVA sensitization groups, whereas MUC5B mucin levels were significantly elevated in the OVA sensitization and e-cigarette-exposed OVA sensitization groups. The results may suggest that the exposure to e-cigarette vapor in an asthmatics promoted allergic inflammation and increased mucin secretion, ultimately leading to the exacerbation of asthma.

Machine learning-driven identification of air toxic combinations associated with asthma symptoms among elementary school children in Spokane, Washington, USA.

Air toxics are atmospheric pollutants with hazardous effects on health and the environment. Although methodological constraints have limited the number of air toxics assessed for associations with health and disease, advances in machine learning (ML) enable the assessment of a much larger set of environmental exposures. We used ML methods to conduct a retrospective study to identify combinations of 109 air toxics associated with asthma symptoms among 269 elementary school students in Spokane, Washington. Data on the frequency of asthma symptoms for these children were obtained from Spokane Public Schools. Their exposure to air toxics was estimated by using the Environmental Protection Agency's Air Toxics Screening Assessment and National Air Toxics Assessment. We defined three exposure periods: the most recent year (2019), the last three years (2017-2019), and the last five years (2014-2019). We analyzed the data using the ML-based Data-driven ExposurE Profile (DEEP) extraction method. DEEP identified 25 air toxic combinations associated with asthma symptoms in at least one exposure period. Three combinations (1,1,1-trichloroethane, 2-nitropropane, and 2,4,6-trichlorophenol) were significantly associated with asthma symptoms in all three exposure periods. Four air toxics (1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, BIS (2-ethylhexyl) phthalate (DEHP), and 2,4-dinitrophenol) were associated only in combination with other toxics, and would not have been identified by traditional statistical methods. The application of DEEP also identified a vulnerable subpopulation of children who were exposed to 13 of the 25 significant combinations in at least one exposure period. On average, these children experienced the largest number of asthma symptoms in our sample. By providing evidence on air toxic combinations associated with childhood asthma, our findings may contribute to the regulation of these toxics to improve children's respiratory health.

Investigation analysis of the acute asthma risk factor and phenotype based on relational analysis with outdoor air pollutants in Xi'an, China.

Asthma is a common chronic heterogeneous disease. Outdoor air pollutants are an important cause of acute asthma. Until now, the association between the risk of acute asthma and outdoor air pollutants is unclear. And the relationship between the different phenotypes of asthma and outdoor air pollutants has not been reported. Thus, an analysis of the association between outdoor air pollutants and daily acute asthma inpatient and outpatient visits in Xi'an, China, from January 1 to December 31, 2018, was conducted. A total of 3395 people were included in the study. The statistical analysis and relational analysis based on the logistic regression were used for illustrating the relatedness of the acute asthma risk factor and phenotype with outdoor air pollutants, while the age, gender, pollen peak and non-pollen peak periods, high type 2 (T2) asthma and non-high T2 asthma were also stratified. Results showed that particulate matter with particle size below 10 µm and 2.5 µm (PM10 and PM2.5), sulfur dioxide(SO2), nitrogen dioxide(NO2), and carbon monoxide(CO) increase the risk of acute asthma and that air pollutants have a lagged effect on asthma patients. PM10, NO2, CO, and Ozone (O3) are associated with an increased risk of acute attacks of high T2 asthma. PM10, PM2.5, SO2, NO2 and CO are associated with an increased risk of acute asthma in males of 0-16 years old. PM10 and PM2.5 are more harmful to asthma patients with abnormal lung function.

Dictamnus dasycarpus Turcz. attenuates airway inflammation and mucus hypersecretion by modulating the STAT6-STAT3/FOXA2 pathway.

BACKGROUND: Effects of Dictamnus dasycarpus Turcz. on allergic asthma and their underlying mechanisms remain unclarified. Thus, we investigated the effects of D. dasycarpus Turcz. water extract (DDW) on mucus hypersecretion in mice with ovalbumin (OVA)-induced asthma and human bronchial epithelial cells. METHODS: BALB/c mice were used to establish an OVA-induced allergic asthma model. Mice were grouped into the OVA sensitization/challenge, 100 and 300 mg/kg DDW treatment, and dexamethasone groups. In mice, cell counts in bronchoalveolar lavage fluid (BALF), serum and BALF analyses, and histopathological lung tissue analyses were performed. Furthermore, we confirmed the basic mechanism in interleukin (IL)-4/IL-13-treated human bronchial epithelial cells through western blotting. RESULTS: In OVA-induced asthma mice, DDW treatment reduced inflammatory cell number and airway hyperresponsiveness and ameliorated histological changes (immune cell infiltration, mucus secretion, and collagen deposition) in lung tissues and serum total immunoglobulin E levels. DDW treatment lowered BALF IL-4, IL-5, and IL-13 levels; reduced levels of inflammatory mediators, such as thymus- and activation-regulated chemokine, macrophage-derived chemokine, and interferon gamma-induced protein; decreased mucin 5AC (MUC5AC) production; decreased signal transducer and activator of transcription (STAT) 6 and STAT3 expression; and restored forkhead box protein A2 (FOXA2) expression. In IL-4/IL-13-treated human bronchial epithelial cells, DDW treatment inhibited MUC5AC production, suppressed STAT6 and STAT3 expression (related to mucus hypersecretion), and increased FOXA2 expression. CONCLUSIONS: DDW treatment modulates MUC5AC expression and mucus hypersecretion by downregulating STAT6 and STAT3 expression and upregulating FOXA2 expression. These findings provide a novel approach to manage mucus hypersecretion in asthma using DDW.

Therapeutic potential of flavonoids in ovalbumin induced asthma in mice model.

OBJECTIVES: Desmodium triquetrum DC (Fabaceae) is a plant commonly used in Indian traditional medicine to treat allergies. Asthma is a severe condition, with an estimated 300 million deaths annually, which could increase to 400 million by 2025. Flavonoids, a class of compounds found in many plants, have been found to have beneficial effects in treating asthma. In this study, researchers focused on three flavonoids, Baicalein, Naringin, and Neohesperidin, derived from Desmodium triquetrum DC, to investigate their potential as a treatment for asthma. METHODS: The study used an aerosolized ovalbumin-induced asthma model to evaluate the effects of the flavonoids on various substances in bronchoalveolar lavage fluid, including total differential leukocyte, nitrite, nitrate, TNF, IL-4, and IL-13. The researchers also measured the levels of myeloperoxidase and malondialdehyde in the lungs. RESULTS: The results showed that ovalbumin-induced airway hyper-responsiveness led to a significant increase in pro-inflammatory cytokine levels. However, the flavonoids significantly decreased the severity of airway inflammation. Histopathology results also supported the effectiveness of the flavonoids. These findings suggest that these flavonoids could be a supplementary and alternative treatment for asthma by inhibiting the pro-inflammatory pathway. CONCLUSIONS: The findings suggest that the isolated compounds have the potential to act cumulatively to decrease the levels of the tested cytokines, normalize eosinophil and activated lymphocyte counts, and significantly reduce MPO and MDA. This indicates a possible respiratory mechanism of action for the drugs.

Protopine ameliorates OVA-induced asthma through modulatingTLR4/MyD88/NF-κB pathway and NLRP3 inflammasome-mediated pyroptosis.

BACKGROUND: Chronic airway inflammation and hyperresponsiveness are characteristics of asthma. The isoquinoline alkaloid protopine (PRO) has been shown to exert anti-inflammatory effects, but its mechanism of action in asthma is not known. PURPOSE: Investigate the protective properties of PRO upon asthma and elucidate its mechanism. STUDY DESIGN AND METHODS: The effects of PRO in asthma treatment were assessed by histology, biochemical analysis, and real-time reverse transcription-quantitative polymerase chain reaction. Then, we integrated molecular docking, western blotting, cellular experiments, immunohistochemistry, immunofluorescence analysis, flow cytometry, and metabolomics analysis to reveal its mechanism. RESULTS: In vivo, PRO therapy reduced the number of inflammatory cells (eosinophils, leukocytes, monocytes) in bronchoalveolar lavage fluid (BALF), ameliorated pathologic alterations in lung tissues, and inhibited secretion of IgG and histamine. Molecular docking showed that PRO could dock with the proteins of TLR4, MyD88, TRAF6, TAK1, IKKα, and TNF-α. Western blotting displayed that PRO inhibited the TLR4/NF-κB signaling pathway. PRO regulated expression of the pyroptosis-related proteins NLR family pyrin domain containing 3 (NLRP3) inflammasome, gasdermin D, caspase-1, and drove caspase-1 inactivation to affect inflammatory responses by inhibiting the NLRP3 inflammasome. In vitro, 24 h after treatment with PRO, cell activity, as well as levels of reactive oxygen species (ROS) and interleukin (IL)-1ß and IL-18, decreased significantly. Immunofluorescence staining showed that PRO decreased expression of TLR4 and MyD88 in vitro. PRO decreased nuclear translocation of NF-κB p65. Twenty-one potential biomarkers in serum were identified using metabolomics analysis, and they predominantly controlled the metabolism of phenylalanine, tryptophan, glucose, and sphingolipids. CONCLUSION: PRO reduced OVA-induced asthma. The underlying mechanism was associated with the TLR4/MyD88/NF-κB pathway and NLRP3 inflammasome-mediated pyroptosis.

Overexpression of Homeobox A1 Relieves Ovalbumin-Induced Asthma in Mice and Is Associated with Blocking of the NF-κB Signaling Pathway.

Homeobox A1 (HOXA1) is a protein coding gene involved in regulating immunity signaling. This study aims to explore the function and mechanism of HOXA1 in asthma. An asthma mouse model was established via ovalbumin (OVA) induction. Airway hyperresponsiveness was evaluated by the value of pause enhancement (Penh). Inflammatory cells in bronchoalveolar lavage fluid (BALF) were detected by Trypan blue and Wright staining. The pathological morphology of lung tissues was assessed by H&E staining. The IgE and inflammatory biomarkers (IL-1ß, IL-6, IL-17, and TNF-α) in BALF and lung tissues were measured by ELISA. Western blot was performed to detect the expression of NF-κB pathway-related proteins. HOXA1 was down-regulated in OVA-induced asthmatic mice. Overexpression of HOXA1 decreased Penh and relieved pathological injury of lung tissues in OVA-induced mice. Overexpression of HOXA1 also reduced the numbers of total cells, leukocytes, eosinophils, neutrophils, macrophages, and lymphocytes, as well as the levels of IgE, IL-1ß, IL-6, IL-17, and TNF-α in BALF of OVA-induced mice. The inflammatory biomarkers were also decreased in lung tissues by HOXA1 overexpression. In addition, HOXA1 overexpression blocked the NF-κB signaling pathway in OVA-induced mice. Overexpression of HOXA1 relieved OVA-induced asthma in female mice, which is associated with the blocking of the NF-κB signaling pathway.

Oxidative stress-mediated activation of FTO exacerbates impairment of the epithelial barrier by up-regulating IKBKB via N6-methyladenosine-dependent mRNA stability in asthmatic mice exposed to PM2.5.

In order to comprehend the underlying mechanisms contributing to the development and exacerbation of asthma resulting from exposure to fine particulate matter (PM2.5), we established an asthmatic model in fat mass and obesity-associated gene knockdown mice subjected to PM2.5 exposure. Histological analyses using hematoxylin-eosin (HE) and Periodic Acid-Schiff (PAS) staining revealed that the down-regulation of the fat mass and obesity-associated gene (Fto) expression significantly ameliorated the pathophysiological alterations observed in asthmatic mice exposed to PM2.5. Furthermore, the down-regulation of Fto gene expression effectively attenuated damage to the airway epithelial barrier. Additionally, employing in vivo and in vitro models, we elucidated that PM2.5 modulated FTO expression by inducing oxidative stress. Asthmatic mice exposed to PM2.5 exhibited elevated Fto expression, which correlated with increased levels of reactive oxygen species. Similarly, when cells were exposed to PM2.5, FTO expression was up-regulated in a ROS-dependent manner. Notably, the administration of N-acetyl cysteine successfully reversed the PM2.5-induced elevation in FTO expression. Concurrently, we performed transcriptome-wide Methylated RNA immunoprecipitation Sequencing (MeRIP-seq) analysis subsequent to PM2.5 exposure. Through the implementation of Gene Set Enrichment Analysis and m6A-IP-qPCR, we successfully identified inhibitor of nuclear factor kappa B kinase subunit beta (IKBKB) as a target gene regulated by FTO. Interestingly, exposure to PM2.5 led to increased expression of IKBKB, while m6A modification on IKBKB mRNA was reduced. Furthermore, our investigation revealed that PM2.5 also regulated IKBKB through oxidative stress. Significantly, the down-regulation of IKBKB effectively mitigated epithelial barrier damage in cells exposed to PM2.5 by modulating nuclear factor-kappa B (NF-κB) signaling. Importantly, we discovered that decreased m6A modification on IKBKB mRNA facilitated by FTO enhanced its stability, consequently resulting in up-regulation of IKBKB expression. Collectively, our findings propose a novel role for FTO in the regulation of IKBKB through m6A-dependent mRNA stability in the context of PM2.5-induced oxidative stress. Therefore, it is conceivable that the utilization of antioxidants or inhibition of FTO could represent potential therapeutic strategies for the management of asthma exacerbated by PM2.5 exposure.