Influence of o,p'-DDT on MUC5AC expression via regulation of NF-κB/AP-1 activation in human lung epithelial cells

Transforming growth factor-β3/Smad2/Smad3 signaling pathway inhibition and autophagy by the Yunpi-Xiefei-Huatan decoction ameliorated airway inflammation and mucus hypersecretion in asthmatic rats

ETHNOPHARMACOLOGICAL RELEVANCE

The Yunpi-Xiefei-Huatan decoction (YXHD) is a traditional Chinese medicine that can improve asthma-related symptoms, including cough, phlegm in the throat, and shortness of breath. However, the YXHD mechanism on asthma has not yet been elucidated.

STUDY AIM

The aim of this study is to investigate the effect of YXHD on airway inflammation, mucus hypersecretion, and autophagy modulation in asthma.

MATERIALS AND METHODS

The YXHD chemical constituents were observed and analyzed using high-performance liquid chromatography-mass spectrometry. Ovalbumin sensitization and stimulation were used to establish an asthma rat model. A total of 80 Sprague-Dawley (SD) rats were segmented into eight groups at random: a Normal (NC) group, a Model (Mod) group, a YXHD low-dose group (10 g/kg/d), a YXHD moderate-dose group (20 g/kg/d), a YXHD high-dose group (40 g/kg/d), a Rapamycin group (4 mg/kg/d), a 3-methyladenine (3-MA) group (15 mg/kg/d), and a Dexamethasone (DEX) group (0.5 mg/kg/d). Whole-body plethysmography (WBP) detection was used to evaluate airway hyperresponsiveness. An enzyme-linked immunosorbent assay (ELISA) was used to detect inflammatory factors in the peripheral blood. Inflammatory cells in the bronchoalveolar lavage fluid (BALF) were also counted. Pathological changes in the lung tissues were marked using hematoxylin and eosin (H&E) staining and periodic acid-Schiff (PAS) staining. The localization of MUC5AC and the co-localization of LC3B + MUC5AC were observed using immunofluorescence. The expressions of autophagy and the TGF-β3/Smad2/Smad3 pathway in the lung tissues were detected using a Western blot assay (WB) and qPCR, and the autophagosomes in the lung tissues were detected using a transmission electron microscope (TEM).

RESULTS

Twenty signal peaks were identified using ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) technology. The TGF-β3/Smad2/Smad3 signal pathway activation was induced using ovalbumin (OVA) exposure in the rats. The upregulated expression of autophagy, enhanced MUC5AC fluorescence and LC3B fluorescence, and their co-localized expression in the airway epithelium indicated inflammatory cell infiltration and excessive mucus secretion in the lungs. This resulted in airway hyper-responsiveness. The YXHD inhibited the activation of the TGF-β3/Smad2/Smad3 signaling pathway, and autophagy expression reduced inflammatory factors, abnormal mucus secretion, and airway hyperresponsiveness.

CONCLUSION

The YXHD improved lung function, relieved lung inflammation, and inhibited airway mucus secretions in asthmatic rat models. Its mechanism may have been related to the blockage of the TGF-β3/Smad2/Smad3 signaling pathway and autophagy downregulation.

Molecular Mechanism of Action of Endocrine-Disrupting Chemicals on the Respiratory System

Endocrine-disrupting chemicals (EDCs) are a growing health hazard for humankind and respiratory health in particular. Such chemical compounds are present in the environment and food and may interfere with physiological processes through interference with functions of the endocrine system, making humans more susceptible to various types of diseases. This review aims to discuss the effects of EDCs on the respiratory system. Exposure to EDCs during fetal development and adulthood increases susceptibility to respiratory diseases such as asthma, COPD, and pulmonary fibrosis. EDCs are both multiple and complex in the ways they can act. Indeed, these chemicals may induce oxidative stress, modify cell proliferation and differentiation, interfere with tissue repair, and modulate the inflammatory response. Moreover, EDCs may also break the integrity of the blood-air barrier, allowing noxious substances to penetrate into the lung and thus enhancing the opportunity for infection. In conclusion, the scientific evidence available tends to indicate that EDCs exposure is strongly linked to the initiation of respiratory disease. Further research will be important in discovering the underlying molecular mechanisms and devising preventive and therapeutic measures.

Cross-sectional and longitudinal associations of dichlorodiphenyltrichloroethane (DDT) metabolites exposure with lung function alternation in the Chinese general adults

Exposure of dichlorodiphenyltrichloroethane (DDT) pesticide was suggested to be associated with adverse effects on the respiratory system. However, the effects of DDT exposure on lung function remain unclear. Our objectives were to investigate the potential associations of internal levels of DDT and its metabolites including dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) with lung function. Serum DDT, DDE, and DDD concentrations and lung function were measured among 3968 general adults from the Wuhan-Zhuhai cohort. The cross-sectional and longitudinal associations of serum DDT and its metabolites with lung function were assessed using linear mixed models. The results showed negative dose-response relationships of serum DDT, DDE, and DDD levels with forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). In the cross-sectional analyses, each 1-unit increase in natural log-transformed values of p,p'-DDE, o,p'-DDT, o,p'-DDE, or p,p'-DDD was significantly associated with a 25.77-, 44.84-, 51.13-, or 43.44-mL decrease in FVC, respectively. Each 1-unit increase in natural log-transformed values of o,p'-DDT, o,p'-DDE, o,p'-DDD, or p,p'-DDD was significantly associated with a 35.72-, 31.87-, 29.54-, or 36.80-mL decrease in FEV1, respectively. In the three-year longitudinal analyses, each 1-unit increase in natural log-transformed serum p,p'-DDT and p,p'-DDE was significantly associated with a 35.10 mL and 36.38 mL decrease in FVC, and a 26.32 mL and 32.37 mL decrease in FEV1, respectively. In conclusion, DDT and its metabolites exposure were associated with lung function decline in the general Chinese adult population.

Airborne particulate matter (PM10) induces cell invasion through Aryl Hydrocarbon Receptor and Activator Protein 1 (AP-1) pathway deregulation in A549 lung epithelial cells

BACKGROUND

Particulate matter with an aerodynamic size ≤ 10 μm (PM₁₀) is a risk factor for lung cancer development, mainly because some components are highly toxic. Polycyclic aromatic hydrocarbons (PAHs) are present in PM₁₀, such as benzo[a]pyrene (BaP), which is a well-known genotoxic and carcinogenic compound to humans, capable of activating AP-1 transcription factor family genes through the Aryl Hydrocarbon Receptor (AhR). Because effects of BaP include metalloprotease 9 (MMP-9) activation, cell invasion, and other pathways related to carcinogenesis, we aimed to demonstrate that PM₁₀ (10 µg/cm²) exposure induces the activation of AP-1 family members as well as cell invasion in lung epithelial cells, through AhR pathway.

METHODS AND RESULTS

The role of the AhR gene in cells exposed to PM₁₀ (10 µg/cm²) and BaP (1µM) for 48 h was evaluated using AhR-targeted interference siRNA. Then, the AP-1 family members (c-Jun, Jun B, Jun D, Fos B, C-Fos, and Fra-1), the levels/activity of MMP-9, and cell invasion were analyzed. We found that PM₁₀ increased AhR levels and promoted its nuclear localization in A549 treated cells. Also, PM₁₀ and BaP deregulated the activity of AP-1 family members. Moreover, PM₁₀ upregulated the secretion and activity of MMP-9 through AhR, while BaP had no effect. Finally, we found that cell invasion in A549 cells exposed to PM₁₀ and BaP is modulated by AhR.

CONCLUSION

Our results demonstrated that PM₁₀ exposure induces upregulation of the c-Jun, Jun B, and Fra-1 activity, the expression/activity of MMP-9, and the cell invasion in lung epithelial cells, effects mediated through the AhR. Also, the Fos B and C-Fos activity were downregulated. In addition, the effects induced by PM₁₀ exposure were like those induced by BaP, which highlights the potentially toxic effects of the PM₁₀ mixture in lung epithelial cells.

Expression levels and network analysis of inflammamiRs in peripheral blood mononuclear cells exposed to DDE "in vitro"

Recent studies have demonstrated that dichlorodiphenyldichloroethylene (DDE) induced a pro-inflammatory condition in peripheral blood mononuclear cells (PBMC). However, the molecular mechanisms implicated in this condition are poorly understood. Therefore, this study aimed to evaluate miR-155, miR-126, and miR-21 expression levels in PBMC exposed "in vitro" to DDE. PBMC were dosed with increasing concentrations of DDE (10-80 µg mL^-1) at different treatment times (0-24 h). The results showed an up-regulation in the expression levels of assessed miRNAs (miR-155, miR-146, and miR-21) after PBMCs were exposed to DDE. Besides, bioinformatic analysis was performed to understand the biological roles of assessed miRNAs. The bioinformatic analysis shows that assessed miRNAs are associated with regulating signaling pathways involved in cancer, apoptosis, cell cycle, inflammation, metabolism, etc. These findings offer new insights into the molecular mechanisms related to the inflammatory processes and their regulation induced by DDE in PBMC exposed "in vitro".