Fine particulate matter aggravates allergic airway inflammation through thymic stromal lymphopoietin activation in mice

The role of IL-2 cytokine family in asthma

BACKGROUND

The interleukin-2 (IL-2) family of cytokines, including IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21, are pivotal regulators of the immune response, impacting both innate and adaptive immunity. Understanding their molecular characteristics, receptor interactions, and signalling pathways is essential for elucidating their roles in health and disease.

OBJECTIVES

This review provides a comprehensive overview of the IL-2 family of cytokines, highlighting their molecular biology, receptor interactions, and signalling mechanisms. Furthermore, it explores the involvement of IL-2 family cytokines in the pathogenesis of chronic respiratory diseases, with a specific focus on chronic obstructive pulmonary disease (COPD) and asthma.

METHODS

A thorough literature review was conducted to gather insights into the molecular biology, receptor interactions, and signalling pathways of IL-2 family cytokines. Additionally, studies investigating the roles of these cytokines in chronic respiratory diseases, particularly COPD and asthma, were analysed to discern their implications in wider pathophysiology of disease.

RESULTS

IL-2 family cytokines exert pleiotropic effects on immune cells, modulating cellular proliferation, differentiation, and survival. Dysregulation of IL-2 family cytokines has been implicated in the pathogenesis of chronic respiratory illnesses, including COPD and asthma. Elevated levels of IL-2 and IL-9 have been associated with disease severity in COPD, while IL-4 and IL-9 play crucial roles in asthma pathogenesis by promoting airway inflammation and remodelling.

CONCLUSION

Understanding the intricate roles of IL-2 family cytokines in chronic respiratory diseases provides valuable insights into potential therapeutic targets for these conditions. Targeting specific cytokines or their receptors may offer novel treatment modalities to attenuate disease progression and improve clinical outcomes in patients with COPD and asthma.

Severe Asthmatic Responses: The Impact of TSLP

Asthma is a chronic inflammatory disease that affects the lower respiratory system and includes several categories of patients with varying features or phenotypes. Patients with severe asthma (SA) represent a group of asthmatics that are poorly responsive to medium-to-high doses of inhaled corticosteroids and additional controllers, thus leading in some cases to life-threatening disease exacerbations. To elaborate on SA heterogeneity, the concept of asthma endotypes has been developed, with the latter being characterized as T2-high or low, depending on the type of inflammation implicated in disease pathogenesis. As SA patients exhibit curtailed responses to standard-of-care treatment, biologic therapies are prescribed as adjunctive treatments. To date, several biologics that target specific downstream effector molecules involved in disease pathophysiology have displayed superior efficacy only in patients with T2-high, eosinophilic inflammation, suggesting that upstream mediators of the inflammatory cascade could constitute an attractive therapeutic approach for difficult-to-treat asthma. One such appealing therapeutic target is thymic stromal lymphopoietin (TSLP), an epithelial-derived cytokine with critical functions in allergic diseases, including asthma. Numerous studies in both humans and mice have provided major insights pertinent to the role of TSLP in the initiation and propagation of asthmatic responses. Undoubtedly, the magnitude of TSLP in asthma pathogenesis is highlighted by the fact that the FDA recently approved tezepelumab (Tezspire), a human monoclonal antibody that targets TSLP, for SA treatment. Nevertheless, further research focusing on the biology and mode of function of TSLP in SA will considerably advance disease management.

Ferroptosis is involved in PM2.5-induced acute nasal epithelial injury via AMPK-mediated autophagy

PM2.5 is one of the main harmful environmental pollutants and can damage nasal epithelial carriers to worsen allergic rhinitis. Ferroptosis is a novel form of regulated cell death with iron-dependent lipid peroxidation. However, whether ferroptosis is involved in PM2.5-induced nasal epithelial injury has not been elucidated. To verify the vital role of ferroptosis in PM2.5-induced nasal epithelial injury and further explore the potential mechanism, we detected intracellular iron content, ROS release and lipid peroxidation and ferroptosis-related proteins in vitro as well as the pathological changes in the nasal epithelium and the levels of proinflammatory factors in nasal lavage fluid in vivo. Our results showed that PM2.5 exposure led to oxidative stress, labile iron accumulation and lipid peroxidation in HNEPCs. In addition, the expression levels of xCT, GPx4, FTH1 and FTL in HNEPCs were greatly inhibited by PM2.5. Treatment with the ferroptosis inhibitors deferoxamine (DFO) and ferrostatin-1 (Fer-1) significantly reversed the toxicity of PM2.5 to human nasal epithelial cells (HNEPCs). Mechanistically, AMPK-mediated autophagy was initiated during PM2.5 exposure, which drove ferroptosis of HNEPCs. Autophagy inhibitor remarkably improved cell death, oxidative stress, labile iron accumulation, lipid peroxidation, and the downregulated expression of xCT, GPx4, FTH1 and FTL in HNEPCs induced by PM2.5. Furthermore, an AMPK inhibitor (Compound C, CC) and siRNA-AMPKα suppressed autophagy activation and ferroptosis stimulated by PM2.5. In vivo, Fer-1 reduced nasal epithelial injury and mucus secretion in PM2.5-exposed mice. In addition, CC significantly improved nasal epithelial damage and proinflammatory factor production in mice caused by PM2.5 intranasal treatment. In addition, CC greatly inhibited autophagy activation but reversed the downregulation of GPX4 and FTH1 induced by PM2.5 in the nasal epithelium of mice. Together, these data suggest that AMPK-mediated autophagy plays an important role in PM2.5-induced ferroptosis and that AMPK might be a potential treatment target for PM2.5-induced nasal epithelial injury.

Lithocholic acid-tryptophan conjugate (UniPR126) based mixed micelle as a nano carrier for specific delivery of niclosamide to prostate cancer via EphA2 receptor

Targeted delivery of chemotherapeutic agents is considered a prominent strategy for the treatment of cancer due to its site-specific delivery, augmented penetration, bioavailability, and improved therapeutic efficiency. In the present study, we employed UniPR126 as a carrier in a mixed nanomicellar delivery system to target and deliver anticancer drug NIC specifically to cancer cells via EphA2 receptors as these receptors are overexpressed in cancer cells but not in normal cells. The specificity of the carrier was confirmed from the significant enhancement in the uptake of coumarin-6 loaded mixed nanomicelle by EphA2 highly expressed PC-3 cells compared to EphA2 low expressed H4 cells. Further, niclosamide-loaded lithocholic acid tryptophan conjugate-based mixed nanomicelle has shown significant synergistic cytotoxicity in PC-3 but not in H4 cells. In vivo anticancer efficacy data in PC-3 xenograft revealed a significant reduction in the tumor volume (66.87%) with niclosamide-loaded lithocholic acid tryptophan conjugate nanomicelle, where pure niclosamide showed just half of the activity. Molecular signaling data by western blotting also indicated that niclosamide-loaded lithocholic acid tryptophan conjugate nanomicelle interfered with the EphA2 receptor signaling and inhibition of the Wnt/beta-catenin pathway and resulted in the synergistic anticancer activity compared to niclosamide pure drug.

Effect of exposure to fine particulate matter during pregnancy and infancy on paediatric allergic rhinitis

BACKGROUND

The effect of prenatal and postnatal exposure to fine particulate matter (PM_2.5) on the development of allergic rhinitis (AR) is poorly understood. We further identified the vulnerable period for AR development to determine methods to decrease adverse effects.

METHODS

We used a large population-based birth cohort of 140 911 singleton live infants in Taichung, Taiwan with a highly temporal-resolution satellite-based hybrid model to evaluate the effects of prenatal and early postnatal exposure on the onset of AR.

RESULTS

Among 140 911 children, 47 276 (33.55%) were cases of incident AR. The mean age of the children with AR at initial diagnosis was 2.97±1.78 years. We identified a significant association of AR with an interquartile range (IQR 17.98 µg/m³) increase in PM_2.5 from 30 gestational weeks to 52 weeks after birth. The exposure-response relationship revealed that AR had a significant positive association between PM_2.5 of 26-76 µg/m³ (adjusted hazard ratios ranged from 1.00 to 1.05).

CONCLUSION

Our study provides evidence that both prenatal and postnatal exposures to PM_2.5 are associated with later development of AR. The vulnerable time window may be within late gestation and the first year of life. Further study is required to confirm the vulnerable time period of PM_2.5 on AR.

Airborne particulate matter from goat farm increases acute allergic airway responses in mice

Background: Inhalation exposure to biological particulate matter (BioPM) from livestock farms may provoke exacerbations in subjects suffering from allergy and asthma. The aim of this study was to use a murine model of allergic asthma to determine the effect of BioPM derived from goat farm on airway allergic responses.Methods: Fine (<2.5 μm) BioPM was collected from an indoor goat stable. Female BALB/c mice were ovalbumin (OVA) sensitized and challenged with OVA or saline as control. The OVA and saline groups were divided in sub-groups and exposed intranasally to different concentrations (0, 0.9, 3, or 9 μg) of goat farm BioPM. Bronchoalveolar lavage fluid (BALF), blood and lung tissues were collected.Results: In saline-challenged mice, goat farm BioPM induced 1) a dose-dependent increase in neutrophils in BALF and 2) production of macrophage inflammatory protein-3a. In OVA-challenged mice, BioPM induced 1) inflammatory cells in BALF, 2) OVA-specific Immunoglobulin (Ig)G1, 3) airway mucus secretion-specific gene expression. RNAseq analysis of lungs indicates that neutrophil chemotaxis and oxidation-reduction processes were the representative genomic pathways in saline and OVA-challenged mice, respectively.Conclusions: A single exposure to goat farm BioPM enhanced airway inflammation in both saline and OVA-challenged allergic mice, with neutrophilic response as Th17 disorder and eosinophilic response as Th2 disorder indicative of the severity of allergic responses. Identification of the mode of action by which farm PM interacts with airway allergic pathways will be useful to design potential therapeutic approaches.

Air Quality Variation in Wuhan, Daegu, and Tokyo during the Explosive Outbreak of COVID-19 and Its Health Effects

This study was designed to assess the variation of the air quality actually measured from the air pollution monitoring stations (AQMS) in three cities (Wuhan, Daegu, and Tokyo), in Asian countries experiencing the explosive outbreak of COVID-19, in a short period of time. In addition, we made a new attempt to calculate the reduced Dose_PM2.5 (μg) at the bronchiolar (Br.) and alveolar-interstitial (AI) regions of the 10-year-old children after the city lockdown/self-reflection of each city. A comparison of the average PM_2.5 of a month before and after the lockdown (Wuhan) and self-reflection (Daegu and Tokyo) clearly shows that the PM_2.5 concentration was decreased by 29.9, 20.9, and 3.6% in Wuhan, Daegu and Tokyo, respectively. Wuhan, Daegu and Tokyo also recorded 53.2, 19.0, and 10.4% falls of NO₂ concentration, respectively. Wuhan, which had the largest decrease of PM_2.5 concentration due to COVID-19, also marked the largest reduced Dose_{PM2.5 10-year-old children} (μg) (3660 μg at Br. and 6222 μg at AI), followed by Daegu (445 μg at Br. and 1287 μg at AI), and Tokyo (18 μg at Br. and 52 μg at AI), over two months after the city lockdown/self-reflection. Our results suggest that the city lockdown/self-reflection had the effect of lowering the concentration of PM_2.5, resulting in an extension of the period it took to the acute allergic airway inflammation (AAI) for the 10-year-old children.

Livestock farm particulate matter enhances airway inflammation in mice with or without allergic airway disease

Effects of airborne biological particulate matter (BioPM; from livestock farms) on the pulmonary airways are not well studied. The aim of the present study was to investigate whether fine (<2.5 μm) BioPM derived from indoor animal stables (two chicken and two pig farms) could modify airway allergic responses by using a mouse model of allergic airway disease (allergic asthma). After intraperitoneal ovalbumin (OVA) sensitization mice were either intranasally challenged with OVA (allergic mice) or saline (non-allergic controls). Mice were also intranasally treated with farm-derived BioPM. Bronchoalveolar lavage fluid (BALF), blood and lung tissues were collected one day after intranasal exposure. BioPM from all the farms caused an acute neutrophilic inflammatory response in non-allergic mice. In allergic mice, BioPM derived from pig farm 2 induced a larger cellular inflammatory response than other farm-derived BioPM. All farm BioPM elicited Th17 cytokine (Interleukin (IL)-23) production except chicken farm 2, whereas Th2 cytokine (IL-5) increase was only induced by BioPM collected from chicken farm 2. These results indicate the exposure of BioPM from chicken and pig farms may cause the enhancement of airway allergic response in mice following exposure to OVA. More variation in the responses between farms was observed in allergic than non-allergic mice. Understanding the source and doses of BioPM that may affect the airway allergic response could help susceptible individuals to avoid worsening their respiratory diseases.

Associations between short-term exposure to fine particulate matter and acute exacerbation of asthma in Yancheng, China

Scarce evidence existed on the association between short-term exposure to fine particulate matter (PM_2.5) and asthma in China. In this study, we aimed to explore the relationship of PM_2.5 with acute asthma exacerbation in a coastal city of China. Cases of acute asthma exacerbation were identified from hospital outpatient visits in Yancheng, China, from 2015 to 2018. We utilized the generalized additive model linked by a quasi-Poisson distribution to assess the association between PM_2.5 and daily acute asthma exacerbation. Different lag structures were built, and we conducted stratification analyses by gender, age, and season. Two-pollutant models were fitted, and concentration-response (C-R) curves were pooled. A total of 3,520 cases of acute asthma exacerbation were recorded, with a daily average of 3. We observed positive and significant associations of PM_2.5 on lag 1, 2, lag 02, and lag 03 day. For each 10-μg/m³ increase in PM_2.5 (lag 02), the associated increment in asthma was 3.15% (95% CI: 0.99%, 5.31%). The association remained after adjusting for gaseous co-pollutants. We observed significant PM_2.5-asthma associations in males, patients ≤64 years, and during cold seasons. The C-R curves were positive and almost linear for total and strata-specific associations. In conclusion, this study provided robust evidence on the association of PM_2.5 with acute asthma exacerbation, which may benefit future prevention strategy and policy making.

In Vitro and In Vivo Experimental Studies of PM2.5 on Disease Progression

Air pollution is a very critical issue worldwide, particularly in developing countries. Particulate matter (PM) is a type of air pollution that comprises a heterogeneous mixture of different particle sizes and chemical compositions. There are various sources of fine PM (PM2.5), and the components may also have different effects on people. The pathogenesis of PM2.5 in several diseases remains to be clarified. There is a long history of epidemiological research on PM2.5 in several diseases. Numerous studies show that PM2.5 can induce a variety of chronic diseases, such as respiratory system damage, cardiovascular dysfunction, and diabetes mellitus. However, the epidemiological evidence associated with potential mechanisms in the progression of diseases need to be proved precisely through in vitro and in vivo investigations. Suggested mechanisms of PM2.5 that lead to adverse effects and chronic diseases include increasing oxidative stress, inflammatory responses, and genotoxicity. The aim of this review is to provide a brief overview of in vitro and in vivo experimental studies of PM2.5 in the progression of various diseases from the last decade. The summarized research results could provide clear information about the mechanisms and progression of PM2.5-induced disease.