Background: Eupatilin is an active flavon extracted from the Artemisia species and has properties such as antioxidant, anti-inflammatory, and anti-cancer. We examined the effect of eupatilin using fine particulate matter (FPM) and human bronchial epithelial cell line (BEAS-2B) to confirm the potential of eupatilin as a therapeutic agent for respiratory diseases caused by FPM. Methods: Reactive oxygen species (ROS) levels were checked by flow cytometry to identify if FPM and eupatilin affect ROS production. Western blotting was performed to identify the mechanism of action of eupatilin in FPM-exposed BEAS-2B cells. Results: When cells were exposed to FPM above 12.5 μg/mL concentration for 24 h, ROS production increased significantly compared to the control. When eupatilin was added to cells exposed to FPM, the ROS level decreased proportionally with the eupatilin dose. The phosphorylation of Akt, NF-κB p65, and p38 MAPK induced by FPM was significantly reduced by eupatilin, respectively. Conclusion: FPM cause respiratory disease by producing ROS in bronchial epithelial cells. Eupatilin has been shown to inhibit ROS production through altering signaling pathways. The ROS inhibiting property of eupatilin can be exploited in FPM induced respiratory disorders.

Background and Objectives: Fine particulate matter, PM_2.5, is becoming a major threat to human health, particularly in terms of respiratory diseases. Pyroptosis is a recently discovered and distinct form of cell death, characterized by pore formation in the cell membrane and secretions of proinflammatory cytokines. There has been little research on the effect of PM_2.5 on pyroptosis, especially in airway epithelium. We investigated whether PM_2.5-related oxidative stress induces pyroptosis in bronchial epithelial cells and defined the underlying mechanisms. Materials and Methods: After exposure of a BEAS-2B cell line to PM_2.5 concentration of 20 µg/mL, reactive oxygen species (ROS) levels, parameters related to pyroptosis, and NF-κB signaling were measured by Western blotting, immunofluorescence, and ELISA (Enzyme-linked immunosorbent assay). Results: PM_2.5 induced pyroptotic cell death, accompanied by LDH (Lactate dehydrogenase) release and increased uptake of propidium iodide in a dose-dependent manner. PM_2.5 activated the NLRP3-casp1-gasdermin D pathway, with resulting secretions of the proinflammatory cytokines IL-1β and IL-18. The pyroptosis activated by PM_2.5 was alleviated significantly by NLRP3 inhibitor. In PM_2.5-exposed BEAS-2B cells, levels of intracellular ROS and NF-κB p65 increased. ROS scavenger inhibited the expression of the NLRP3 inflammasome, and the NF-κB inhibitor attenuated pyroptotic cell death triggered by PM_2.5 exposure, indicating that the ROS/NF-κB pathway is involved in PM_2.5-induced pyroptosis. Conclusions: These findings show that PM_2.5 exposure can cause cell injury by NLRP3-inflammasome-mediated pyroptosis by upregulating the ROS/NF-κB pathway in airway epithelium.

Pyroptosis represents a type of cell death mechanism notable for its cell membrane disruption and the subsequent release of proinflammatory cytokines. The Nod-like receptor family pyrin domain containing inflammasome 3 (NLRP3) plays a critical role in the pyroptosis mechanism associated with various diseases resulting from particulate matter (PM) exposure. Tert-butylhydroquinone (tBHQ) is a synthetic antioxidant commonly used in a variety of foods and products. The aim of this study is to examine the potential of tBHQ as a therapeutic agent for managing sinonasal diseases induced by PM exposure. The occurrence of NLRP3 inflammasome-dependent pyroptosis in RPMI 2650 cells treated with PM < 4 µm in size was confirmed using Western blot analysis and enzyme-linked immunosorbent assay results for the pyroptosis metabolites IL-1β and IL-18. In addition, the inhibitory effect of tBHQ on PM-induced pyroptosis was confirmed using Western blot and immunofluorescence techniques. The inhibition of tBHQ-mediated pyroptosis was abolished upon nuclear factor erythroid 2-related factor 2 (Nrf2) knockdown, indicating its involvement in the antioxidant mechanism. tBHQ showed potential as a therapeutic agent for sinonasal diseases induced by PM because NLRP3 inflammasome activation was effectively suppressed via the Nrf2 pathway.

Background and Objectives: Eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) is characterized by type 2 inflammation, marked eosinophil infiltration, and enhanced epithelial–mesenchymal transition (EMT). Although interleukin-5 (IL-5) is central to eosinophil differentiation and activation, its role in EMT in human nasal epithelial cells (HNECs) remains unclear. This study aimed to elucidate the contribution of IL-5Rα/Janus kinase 2 (JAK2)/signal transducer and activator of transcription 5 (STAT5) signaling in eosinophils in EMT in ECRSwNP. Materials and Methods: Nasal mucosal tissues from control and ECRSwNP or non-ECRSwNP group patients (n = 12 each) were analyzed for type 2 cytokine, EMT marker, and IL-5Rα/JAK2/STAT5 axis component levels using Western blotting, immunohistochemistry, and quantitative real-time polymerase chain reaction. HL-60 cells were differentiated into eosinophil-like cells using butyric acid and stimulated with IL-5, and HNECs were co-cultured with undifferentiated, differentiated, or IL-5-activated differentiated HL-60 cells. EMT induction and migration were assessed using immunofluorescence, wound-healing assays, and Western blotting. IL-5RA, JAK2, or STAT5 was silenced using small interfering RNA to determine pathway dependency. Results: ECRSwNP tissues showed elevated type 2 cytokine and EMT marker expression and enhanced IL-5Rα/JAK2/STAT5 pathway activation. Co-culture with IL-5-activated differentiated HL-60 cells induced EMT in HNECs, evidenced by decreased E-cadherin and zonula occludens-1, increased N-cadherin and vimentin levels, and enhanced migration. Moreover, silencing IL-5RA, JAK2, or STAT5 significantly attenuated these effects. Conclusions: IL-5-activated IL-5Rα/JAK2/STAT5 signaling in eosinophils may contribute to EMT in HNECs. Thus, this pathway could be a potential therapeutic target for tissue remodeling and polyp formation in type 2 chronic rhinosinusitis.