Green tea extract ameliorates macrophage-driven emphysematous lesions in chronic obstructive pulmonary disease induced by cigarette smoke condensate

Turmeric extract alleviates airway inflammation via oxidative stress-driven MAPKs/MMPs pathway

Turmeric (Curcuma longa L.) extract (CLE) has been shown to elicit several pharmacological properties and is widely used in Asian traditional medicine. Herein, we assessed the impact of CLE on airway inflammation in BALB/c mice and A549 cells to clarify the underlying mechanism. An asthmatic mouse model was established by administering ovalbumin (OVA). CLE (100 or 300 mg/kg/day) was orally administered daily from days 18 to 23, with dexamethasone (3 mg/kg/day) used as the positive control. Human airway epithelial cells, A549, were stimulated using recombinant tumor necrosis factor-α. The CLE100 and CLE400 groups exhibited a significant downregulation in eosinophil counts, cytokine levels, and immunoglobulin-E levels. Moreover, CLE administration dose-dependently suppressed oxidative stress and airway inflammation in the lung tissue. CLE administration inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs) and the expression and activity of matrix metalloproteinase (MMP)-9. In vitro, CLE treatment reduced mRNA levels of proinflammatory cytokines, MAPK phosphorylation, and the expression and activity of MMP-2 and MMP-9. Additionally, 50 µg/mL CLE and 2.5 µg/mL curcumin showed similar anti-inflammatory effects. Collectively, our findings revealed that CLE could suppress airway inflammation in asthmatic mice and A549 cells via oxidative stress-driven MAPK/MMPs signaling, suggesting that CLE could be developed as a potential treatment option for patients with asthma.

Pycnogenol-Assisted Alleviation of Titanium Dioxide Nanoparticle-Induced Lung Inflammation via Thioredoxin-Interacting Protein Downregulation

Titanium dioxide nanoparticles (TiO2NPs) are used in products that are applied to the human body, such as cosmetics and food, but their biocompatibility remains controversial. Pycnogenol (PYC), a natural extract of pine bark, exerts anti-inflammatory and antioxidant effects. In this study, we investigated whether PYC effectively alleviates pulmonary toxicity induced by airway exposure to TiO2NPs, and the beneficial effects of PYC were explained through the analysis of changes to the mechanism of cytotoxicity. TiO2NPs induced pulmonary inflammation and mucus production, increased the levels of malondialdehyde, and upregulated thioredoxin-interacting protein (TXNIP) and cleaved-caspase 3 (Cas3) in the lungs of mice. However, PYC treatment reduced the levels of all toxicity markers of TiO2NPs and restored glutathione levels. These antioxidant and anti-inflammatory effects of PYC were also demonstrated in TiO2NP-exposed human airway epithelial cells by increasing the mRNA levels of antioxidant enzymes and decreasing the expression of TXNIP, cleaved-Cas3, and inflammatory mediators. Taken together, our results showed that PYC attenuated TiO2NP-induced lung injury via TXNIP downregulation. Therefore, our results suggest the potential of PYC as an effective anti-inflammatory and antioxidant agent against TiO2NP-induced pulmonary toxicity.

The absence of thioredoxin-interacting protein in alveolar cells exacerbates asthma during obesity

Obesity is associated with an increased incidence of asthma. However, the mechanisms underlying this association are not fully understood. In this study, we investigated the role of thioredoxin-interacting protein (TXNIP) in obesity-induced asthma. Asthma was induced by intranasal injection of a protease from Aspergillus oryzae in normal diet (ND)- or high fat diet (HFD)-fed mice to investigate the symptoms. We measured TXNIP expression in the lungs of patients with asthma and in ND or HFD asthmatic mice. To explore the role of TXNIP in asthma pathogenesis, we induced asthma in the same manner in alveolar type 2 cell-specific TXNIP deficient (TXNIPCre) mice. In addition, the expression levels of pro-inflammatory cytokines were compared based on TXNIP gene expression in A549 cells stimulated with recombinant human tumor necrosis factor alpha. Compared to ND-fed mice, HFD-fed mice had elevated levels of free fatty acids and adipokines, resulting in high reactive oxygen species levels and more severe asthma symptoms. TXNIP expression was increased in both, asthmatic patients and HFD asthmatic mice. However, in experiments using TXNIPCre mice, despite being TXNIP deficient, TXNIPCre mice exhibited exacerbated asthma symptoms. Consistent with this, in vitro studies showed highest expression levels of pro-inflammatory cytokines in TXNIP-silenced cells. Overall, our findings suggest that increased TXNIP levels in obesity-induced asthma is compensatory to protect against inflammatory responses.

Mechanism of circRNA_SMG6 mediating lung macrophage ECM degradation via miR-570-3p in microplastics-induced emphysema

Microplastics (MPs) are plastic particles < 5 mm in diameter, of which polystyrene microplastics (PS-MPs) are representative type. The extracellular matrix (ECM) degradation of macrophages is associated with the development of emphysema. Additionally, circular RNAs (circRNAs) have a regulatory role in epigenetic mechanisms related to lung disease. However, the mechanisms of the ECM degradation and circRNAs in MPs-induced emphysema are still unclear. In our study, Sprague-Dawley (SD) rats were treated with 0, 0.5, 1.0 and 2.0 mg/m3 100 nm PS-MPs for 90 days in an inhalation experiment. PS-MPs-exposed rats showed elevated airway resistance and pulmonary dysfunction. Lung histopathology exhibited inflammatory cell infiltration, septal thickening and alveolar dilatation. Exposure to PS-MPs was able to induce elevated levels of ECM degradation-related markers MMP9 and MMP12, as well as reduced levels of elastin in rat lung tissues. CircRNA_SMG6 is a non-coding RNA (ncRNA) with a homologous circular structure in human, rat and mouse. The expression level of circRNA_SMG6 was decreased in both rat lung tissues exposed to PS-MPs and PS-MPs-treated THP-1 cells. The luciferase reporter gene demonstrated that circRNA_SMG6 combined with miR-570-3p and co-regulated PTEN, the target gene of miR-570-3p. Moreover, overexpression of circRNA_SMG6 or inhibition of miR-570-3p attenuated PS-MPs-induced ECM degradation in THP-1 cells. Taken together, circRNA_SMG6 may have a significant function in the deterioration of emphysema caused by PS-MPs-induced macrophage ECM degradation by regulating miR-570-3p. Our findings reveal a novel mechanism of emphysema caused by PS-MPs and provide valuable information for assessing the health risks of MPs.

Immune Dysregulation in Chronic Obstructive Pulmonary Disease

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

Assessment of toxicological validity using tobacco emission condensates: A comparative analysis of emissions and condensates from 3R4F reference cigarettes and heated tobacco products

The tobacco emission condensate, henceforth referred to as "tobacco condensate," plays a critical role in assessing the toxicity of tobacco products. This condensate, derived from tobacco emissions, provides an optimized liquid concentrate for storage and concentration control. Thus, the validation of its constituents is vital for toxicity assessments. This study used tobacco condensates from 3R4F cigarettes and three heated tobacco product (HTP) variants to quantify and contrast organic compounds (OCs) therein. The hazard index (HI) for tobacco emissions and condensates was determined to ascertain the assessment validity. The total particulate matter (TPM) for 3R4F registered at 17,667 μg cig-1, with its total OC (TOC) at 3777 μg cig-1. HTPs' TPM and TOC were 9342 ± 1918 μg cig-1 and 5258 ± 593 μg stick-1, respectively. 3R4F's heightened TPM likely arises from tar, while HTPs' OC concentrations are influenced by vegetable glycerin (2236-2688 μg stick-1) and propylene glycol (589-610 μg stick-1). During the condensation process, a substantial proportion of OCs in 3R4F smoke underwent significant concentration decreases, in contrast to HTPs, where fewer than half of the examined OCs exhibited notable concentration declines. The HI for tobacco emissions exhibited a marginally higher value compared to tobacco condensate, with variations ranging from 7.92% (HTPs) to 18.6% (3R4F), denoting a minimal differential. These observations emphasize the importance of accurate OC recovery techniques to maintain the validity and reliability of toxicity assessments based on tobacco condensates. This study not only deepens the comprehension of chemical behaviors in tobacco products but also establishes a novel benchmark for their toxicity evaluation, with profound implications for public health strategies and consumer protection.

Tea consumption and risk of lung diseases: a two‑sample Mendelian randomization study

BACKGROUND

Numerous studies have reported the association between tea intake and lung diseases. However, the probable relationship between tea consumption on lung diseases still remain controversial and it is unclear whether these findings are due to reverse causality or confounding factor.

METHODS

In order to systematically investigate the causal connection between tea intake on respiratory system disorders, we employed a two-sample Mendelian randomized (MR) study. Genetic instruments for tea intake were identified from a genome-wide association study (GWAS) involving 447,385 individuals. Data on lung diseases were collected from a variety of publicly available genome-wide association studies. The main method used for MR analysis is the inverse variance weighting (IVW) method. To ensure the accuracy of the findings, further sensitivity analysis was conducted.

RESULTS

The IVW method in our MR analysis revealed no evidence to support a causal relationship between tea intake and lung diseases (IPF: OR = 0.997, 95% CI = 0.994-1.000, p = 0.065; Lung cancer: OR = 1.003, 95% CI = 0.998-1.008, P = 0.261; COPD: OR = 1.001, 95% CI = 0.993-1.006, p = 0.552; acute bronchitis: OR = 0.919, 95% CI = 0.536-1.576, p = 0.759; tuberculosis: OR = 1.002, 95% CI = 0.998-1.008, p = 0.301; pneumonia: OR = 0.789, 95% CI = 0.583-1.068, p = 0.125). The reliability of the results was further demonstrated by four additional MR analysis techniques and additional sensitivity testing.

CONCLUSION

We found no evidence of a link between tea intake on lung diseases in our MR results based on genetic information.