PM2.5 aggravates airway inflammation in asthmatic mice: activating NF-κB via MyD88 signaling pathway

CC16 alleviates PM2.5-induced lung epithelial cell injury and airway inflammation in asthmatic mice by inhibiting ferroptosis

BACKGROUND

Exposure to PM2.5 represents a significant public health challenge, closely associated with the worsening of asthma, a condition that still lacks effective preventive measures. Club Cell 16 kDa protein (CC16), recognized for its anti-inflammatory and antioxidant properties, may serve a protective function in asthma exacerbated by PM2.5; however, the underlying mechanisms, particularly those related to ferroptosis, remain poorly understood.

METHODS

The impact of CC16 on inflammation and ferroptosis was assessed using a TC-1 lung epithelial cell model exposed to PM2.5, as well as an ovalbumin (OVA)-induced asthmatic mouse model also subjected to PM2.5 exposure.

RESULTS

CC16 significantly modulated key regulators of ferroptosis (NRF2, GPX4, SLC7A11, HO-1) and attenuated pro-inflammatory cytokines (IL-13, IL-5, IL-6, IL-1β, IL-17A) in PM2.5-exposed lung epithelial cells. Furthermore, it enhanced pulmonary function while reducing airway inflammation and mucus secretion and inhibited ferroptosis in PM2.5-induced asthmatic mice.

CONCLUSION

CC16 demonstrates promise as a therapeutic agent for PM2.5-induced asthma by modulating ferroptosis and alleviating airway inflammation, thereby providing a novel strategy for asthma management.

The relationship between PM2.5 and the onset and exacerbation of childhood asthma: a short communication

Much is known about the link between air pollution and asthma in adults, particularly fine particulate matter (PM2.5). Studies have found that certain levels of fine PM2.5 can increase airway responsiveness and worsen asthma. PM2.5 may play a role in the onset and exacerbation of childhood asthma. However, there is little in the literature on how PM2.5 affects asthma attacks and exacerbations in children. Asthma is a common chronic disease in children, and air pollution can aggravate it. The effect of PM2.5 on childhood asthma needs further research. By evaluating, reviewing, and collating existing results in this area, this paper aims to explore the relationship between PM2.5 and asthma onset and exacerbation in children.

The role of estrogen receptor β in fine particulate matter (PM2.5) organic extract-induced pulmonary inflammation in female and male mice

Fine particulate matter organic extract (Po) was reported to promote inflammation in the lung. Sex differences were reported in many inflammatory diseases. In this study, we investigated the effects of Po exposure on pulmonary inflammatory response and evaluated the role of sex in this process. While mice were exposed to 100 µg/m³ Po for 12 weeks by an inhalation exposure system, the lung histopathological analysis shown obvious inflammation, the cell numbers in bronchoalveolar lavage fluid (BALF) were significantly increased, and most inflammatory cytokines in BALF were upregulated. The results of factorial analysis of variance shown that there was an interaction between sex and Po exposure in the inflammatory cell numbers and the levels of tumor necrosis factor-α (TNF-α), interleukin-5 (IL-5), and growth-related oncogene/keratinocyte chemoattractant (GRO/KC). Notably, these changes and interactions were diminished while Po-exposed mice were administered with the estrogen receptor β (ERβ) antagonist. We speculated that sex might affect the levels of inflammatory indicators in BALF of Po-exposed mice and female mice were more prone to inflammation while exposed to Po. Moreover, ERβ was involved in these processes. To our knowledge, this is the first investigation about the role of sex in Po-induced adverse effects.

Epigallocatechin Gallate Relieved PM2.5-Induced Lung Fibrosis by Inhibiting Oxidative Damage and Epithelial-Mesenchymal Transition through AKT/mTOR Pathway

Oxidative damage and epithelial-mesenchymal transition (EMT) are main pathological processes leading to the development of PM2.5-induced lung fibrosis. Epigallocatechin gallate (EG), a natural polyphenol extracted from green tea, possesses the ability to combat oxidative stress and inflammation. However, the potential roles of EG in PM2.5-induced lung fibrosis have not been reported yet. In the present study, we investigated whether EG could relieve PM2.5-induced lung injury and fibrosis in vivo and in vitro. To mimic PM2.5-induced lung fibrosis, C57/BL6 mice were intranasally instilled with PM2.5 suspension, and MLE-12 lung epithelial cells were stimulated with PM2.5 (100 μg/mL) in vitro. The results showed that intragastric administration of EG (20 mg/kg/d or 80 mg/kg/d for 8 weeks) significantly prevented lung injury, inflammation, and oxidative stress in PM2.5-induced mice, apart from inhibiting collagen deposition. Additionally, EG treatment also suppressed the activation of AKT/mTOR signaling pathway in lung tissues challenged with PM2.5. In vitro experiments further demonstrated that EG treatment could enhance cell viability in a concentration-dependent manner in PM2.5-treated MLE-12 lung epithelial cells. Also, the overexpression of constitutively active AKT could offset the inhibitory effects of EG on EMT and oxidative stress in PM2.5-treated MLE-12 lung epithelial cells. Finally, AKT overexpression also blocked the inhibitory effect of EG on the phosphorylation of mTOR in PM2.5-treated MLE-12 lung epithelial cells. In conclusion, EG could improve PM2.5-induced lung fibrosis by decreasing oxidative damage and EMT through AKT/mTOR pathway, which might be a potential candidate for the treatment of PM2.5-induced lung fibrosis.