BEAS-2B Cells Research Articles

Hydrogen sulfide donor NaHS inhibits formaldehyde-induced epithelial-mesenchymal transition in human lung epithelial cells via activating TGF-β1/Smad2/3 and MAPKs signaling pathways

Formaldehyde (FA) long term exposure leads to abnormal pulmonary function and small airway obstruction of the patients. Hydrogen sulfide (H2S) is one of the recognized gaseous transmitters involved in a wide range of cellular functions. It is unknown the involvement of H2S in FA-induced lung injury. The purpose of this study is to investigate the therapeutic potential and mechanism of H2S on FA-induced epithelial-mesenchymal transition (EMT) of human lung epithelial cells. The cell viability of Beas2B and A549 cells after FA treatment were assessed using MTT assay. The endogenous H2S was visualized by fluorescence microscopy using of the 7-azido-4-methylcoumarin (AzMC). Cell morphology was observed under phase contrast microscope. The mRNAs and proteins level were evaluated by reverse transcription-polymerase chain reaction and western blotting assays. FA treatment downregulated the endogenous H2S levels and the mRNAs and proteins level of H2S synthesizing enzymes, such as cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST) in Beas2B and A549 cells. FA treatment changed the cell morphology of Beas2B cells from cuboid to a spindle-shape, while declined the protein level of E-cadherin and increased the protein level of Vimentin. Moreover, FA treatment increased the proteins level of transforming growth factor-β1 (TGF-β1), phosphorylated-Smad2 (p-Smad2), phosphorylated-Smad3 (p-Smad3), phosphorylated-extracellular signal-regulated kinase (p-ERK), phosphorylated-c-Jun N-terminal kinase (p-JNK), and phosphorylated-P38 (p-P38). Furthermore, the inhibitors of TGF-β receptor type 1 (TGFβRI) and mitogen-activated protein kinases (MAPKs) signaling pathways reversed FA-induced decrease in E-cadherin expression and increase in Vimentin expression in Beas2B cells. Sodium hydrogen sulfide (NaHS) increased the level of H2S, while reversed FA-induced the low expression of E-cadherin and the high expression of Vimentin, TGF-β1, p-Smad2, p-Smad3, p-ERK, p-JNK, and p-P38. These findings indicates FA treatment downregulating the endogenous H2S in human lung epithelial cells. NaHS may inhibit FA-induced EMT in human lung epithelial cells via modulating TGF-β1/Smad2/3 and MAPKs signaling pathways. Therefore, we demonstrated that supplementation of exogenous H2S may inhibit FA-induced lung injury.

Sappanone A ameliorates acute lung injury through inhibiting the activation of the NF-κB signaling pathway

Acute lung injury (ALI) is a serious respiratory disease characterized by diffuse alveolar injury, and it has emerged as a major concern in clinical practice due to limited treatments. This study aimed to explore the pharmacological effects and regulatory mechanism of sappanone A (SA) on ALI. In vivo, mice were administered with SA followed by intratracheal injection of lipopolysaccharide (LPS) to establish an animal model of ALI. We observed that SA exerted comparable anti-inflammatory effects to dexamethasone, as evidenced by effectively mitigating histopathological abnormalities and suppressing the inflammatory response in the lung tissues of mice with ALI. RNA sequencing analysis revealed that SA significantly inhibited the activation of the nuclear factor kappa B (NF-κB) signaling pathway. In vitro, we found that SA protected BEAS-2B cells against LPS-induced cellular injury and reduced inflammatory cytokine generation. Furthermore, both in vivo and in vitro experiments demonstrated that SA effectively prevented LPS-induced oxidative stress and apoptosis. Consistent with the results of the RNA sequencing analysis, SA significantly inhibited the increased protein expressions of p105, p50, c-REL, as well as the ratios of p-p65/p65 and p-IκBα/IκBα in the lung tissues of mice with ALI and LPS-stimulated BEAS-2B cells. Additionally, SA inhibited the nuclear translocation of p65 in BEAS-2B cells stimulated with LPS. Importantly, specific blockade of the NF-κB signaling pathway using BAY11–7082 was identified to alleviate LPS-induced cellular injury in BEAS-2B cells. Collectively, these findings suggest that SA can ameliorate ALI, at least in part, through the inhibition of NF-κB signaling pathway activation.

Evidence for Cytotoxicity and Mitochondrial Dysfunction in Human Lung Cells Exposed to Biomass Burning Aerosol Constituents: Levoglucosan and 4-Nitrocatechol

Biomass burning (BB) emissions are one of the largest sources of carbonaceous aerosol, posing a significant risk as an airway irritant. Important BB markers include wood pyrolysis emissions, such as levoglucosan (LG) that is an anhydrous sugar bearing a six-carbon ring structure (i.e., 1,6-anhydro-β-D-glucopyranose). Atmospheric chemical aging of BB-derived aerosol (BBA) in the presence of nitrogen oxides (NOx) can yield nitro-aromatic compounds, including 4-nitrocatechol (4NC). There is building evidence that NOx-mediated chemical aging of BBA poses a more serious exposure effect than primary pyrolysis emissions. This study provides a comparative toxicological assessment following the exposure to important BBA marker compounds in human lung cells (i.e., A549 and BEAS-2B) to determine whether aromatic 4NC is more toxic than BBA-bound anhydrous carbohydrate (i.e., LG). We determined inhibitory concentration-50 (IC50) and examined reactive oxygen species (ROS) changes, mitochondrial dysfunction, and apoptosis induction in the two cell lines following exposure to LG and 4NC in a dose-response manner. In the BEAS-2B cells, estimated IC50 values for 4NC were 33 and 8.8 μg mL-1, and for LG were 2546 and ∼ 3 × 107 μg mL-1 at 24 h and 48 h of exposure, respectively. A549 cells exhibited a much higher IC50 value than BEAS-2B cells. LG exposures resulted in mitochondrial stress with viability inhibition, but cells recovered with increasing exposure time. 4NC exposures at 200 μg mL-1 resulted in the induction of apoptosis at 6 h. Mitochondrial dysfunction and ROS imbalance induced the intrinsic apoptotic pathway induction following 4NC exposures. While increased ROS is caused by LG exposure in lung cells, 4NC is a marker of concern during BB emissions, as we observed apoptosis and high mitochondrial ROS in both lung cells at atmospherically-relevant aerosol concentrations. It may be associated with higher airway or inhalation pathologies in higher BBA emissions, such as wildfires or during wood combustion.

Biological effect of U(VI) exposure on lung epithelial BEAS-2B cells

In this study, the biological effects of U(VI) exposure on lung epithelial cells were investigated by MTT assay, immunofluorescence, flow cytometry, and Western blotting. U(VI)-induced stress triggers oxidative stress in cells, activates MAPK signaling pathways, and promotes inflammation. Additionally, U(VI) causes damage to the cell membrane structure and severe DNA injury, impacting the accuracy of transcription and translation. The results demonstrate that U(VI) exposure significantly inhibits cell proliferation and migration. This is attributed to the disruption of the PI3K/AKT/GSK-3β/β-catenin signaling pathway and the reduction in CyclinD1 expression, leading to a delayed cell cycle, decreased growth rate, mitochondrial damage, and reduced energy metabolism. This study provides a comprehensive understanding of the molecular mechanisms underlying uranium-induced cellular toxicity in lung epithelial cells.

NRF2 protects lung epithelial cells from wood smoke particle toxicity

Wildfire smoke is a potential source of oxidative stress in lung epithelial tissue. The response to oxidative stress is controlled by the transcription factor NRF2, which is the central regulator of antioxidant gene expression. If wood smoke particle (WSP) exposure induces reactive oxygen species (ROS) in epithelial cells, then NRF2 may protect against pathological conditions resulting from increased oxidative stress through changes in gene expression. We used two lung epithelial cell lines to test this hypothesis in vitro: A549, which harbor a mutation resulting in constitutive activation of NRF2, and BEAS-2B, which show limited NRF2 activity under basal conditions, but high inducibility during oxidative stress. In BEAS-2B cells, WSP exposure leads to increased cellular ROS, activation of NRF2, and upregulation of the NRF2 target genes NQO1, GCLM, and SRXN1. WSP exposure also increased ROS in A549 cells, although NRF2 activation and antioxidant gene upregulation were less robust as both were basally high in this cell line. Overall, the degree of ROS induction by WSP across cell lines is dependent upon NRF2 activity, and a similar pattern was observed for WSP cytotoxicity. WSP also sensitized both cell lines to the ferroptosis inducer erastin in a manner that is correlated with NRF2 activity. Knockout of NRF2 in A549 resulted in higher WSP-induced ROS generation, cytotoxicity, and erastin sensitivity. Taken together, these results suggest that NRF2 serves as a protective factor against wood smoke induced ROS and oxidative stress in lung epithelial cells.

On the dose-response association of fine and ultrafine particles in an urban atmosphere: toxicological outcomes on bronchial cells at realistic doses of exposure at the Air Liquid Interface

Air pollution and particulate matter (PM) are the leading environmental cause of death worldwide. Exposure limits have lowered to increase the protection of human health; accordingly, it becomes increasingly important to understand the toxicological mechanisms on cellular models at low airborne PM concentrations which are relevant for actual human exposure. The use of air liquid interface (ALI) models, which mimic the interaction between airborne pollutants and lung epithelia, is also gaining importance in inhalation toxicological studies. This study reports the effects of ALI direct exposure of bronchial epithelial cells BEAS-2B to ambient PM1 (i.e. particles with aerodynamic diameter lower than 1 μm). Gene expression (HMOX, Cxcl-8, ATM, Gadd45-a and NQO1), interleukin (IL)-8 release, and DNA damage (Comet assay) were evaluated after 24 h of exposure. We report the dose-response curves of the selected toxicological outcomes, together with the concentration-response association and we show that the two curves differ for specific responses highlighting that concentration-response association may be not relevant for understanding toxicological outcomes. Noteworthy, we show that pro-oxidant effects may be driven by the deposition of freshly emitted particles, regardless of the airborne PM1 mass concentration. Furthermore, we show that reference airborne PM1 metrics, namely airborne mass concentration, may not always reflect the toxicological process triggered by the aerosol.These findings underscore the importance of considering different aerosol metrics to assess the toxicological potency of fine and ultrafine particles. To better protect human health additional metrics should be defined, than account for the properties of the entire aerosol mixture including specific as particle size (i.e. particles with aerodynamic diameter lower than 20 nm), the relevant aerosol sources (e.g., traffic combustion, secondary organic aerosol …) as well as their atmospheric processing (freshly emitted vs aged ones).

Investigation of the abasic sites induced by hydrogen peroxide and methyl methanesulfonate in calf thymus DNA and BEAS-2B cells

The primary goals of this study were to investigate the formation of abasic sites (AP sites) induced by methyl methanesulfonate (MMS) and hydrogen peroxide (H2O2), and to characterize specific types of these pro-mutagenic DNA lesions in calf thymus DNA (CT-DNA), and BEAS-2B human lung normal cell line. Furthermore, these profiles were compared with those observed in leukocytes derived from healthy controls (HC), breast cancer patients (BCP) before treatment, and 5-year survivors. Results indicated that both H2O2 and MMS induced the concentration- and time-dependent formation of AP sites in CT-DNA. To characterize the specific types of AP sites induced by H2O2 or MMS, we performed AP site cleavage assay using putrescine, T7 exonuclease (T7 Exo), and exonuclease III (Exo III). Results showed that the AP sites induced by H2O2 in CT-DNA were predominantly 5’-and 3’-nicked AP sites and no intact AP sites were detected. By contrast, the majority of AP sites generated by MMS in CT-DNA are not excisable and are classified as residual and intact AP sites. Similar approaches were performed in human BEAS-2B cells and comparable observations were confirmed in the cell-based model. Further investigation indicated that the profile of the AP sites observed in Taiwanese HC is identical to that of BEAS-2B cells treated with H2O2 whereas the pattern of AP sites detected in BCP is similar to that of CT-DNA exposed to H2O2, suggesting that these AP sites were produced primarily through reactive oxygen species (ROS) generation. More than 70 % of the AP sites in leukocytes derived from BCP were 5’-nicked and residual AP sites. Furthermore, the characteristics of the AP sites detected in 5-year survivors are comparable with the ones in HC by using putrescine cleavage assay. Overall, we speculate that deficiency in the DNA repair cascade may play a role in mediating the formation of specific types of AP sites detected in BCP.

DNA methylation-mediated FGFR1 silencing enhances NF-κB signaling: implications for asthma pathogenesis.

Fibroblast growth factor receptor 1 (FGFR1) is known to play a crucial role in the pathogenesis of asthma, although the precise mechanism remains unclear. This study aims to investigate how DNA methylation-mediated silencing of FGFR1 contributes to the enhancement of NF-κB signaling, thereby influencing the progression of asthma. RT-qPCR was utilized to assess FGFR1 mRNA levels in the serum of asthma patients and BEAS-2B, HBEpiC, and PCS-301-011 cells. CCK8 assays were conducted to evaluate the impact of FGFR1 overexpression on the proliferation of BEAS-2B, PCS-301-011, and HBEpiC cells. Dual-luciferase and DNA methylation inhibition assays were performed to elucidate the underlying mechanism of FGFR1 gene in asthma. The MassARRAY technique was employed to measure the methylation levels of the FGFR1 DNA. Elevated FGFR1 mRNA levels were observed in the serum of asthma patients compared to healthy controls. Overexpression of FGFR1 in BEAS-2B cells significantly enhanced cell proliferation and stimulated NF-ĸB transcriptional activity in HERK-293T cells. Furthermore, treatment with 5-Aza-CdR, a DNA demethylating agent, markedly increased the expression of FGFR1 mRNA in BEAS-2B, PCS-301-011, and HBEpiC cells. Luciferase activity analysis confirmed heightened NF-ĸB transcriptional activity in FGFR1-overexpressing BEAS-2B cells and BEAS-2B cells treated with 5-Aza-CdR. Additionally, a decrease in methylation levels in the FGFR1 DNA promoter was detected in the serum of asthma patients using the MassARRAY technique. Our findings reveal a potential mechanism involving FGFR1 in the progression of asthma. DNA methylation of FGFR1 inactivates the NF-ĸB signaling pathway, suggesting a promising avenue for developing effective therapeutic strategies for asthma.

Innovative biomarkers TCN2 and LY6E can significantly inhibit respiratory syncytial virus infection

BackgroundRespiratory syncytial virus (RSV) is a prominent etiological agent of lower respiratory tract infections in children, responsible for approximately 80% of cases of pediatric bronchiolitis and 50% of cases of infant pneumonia. Despite notable progress in the diagnosis and management of pediatric RSV infection, the current biomarkers for early-stage detection remain insufficient to meet clinical needs. Therefore, the development of more effective biomarkers for early-stage pediatric respiratory syncytial virus infection (EPR) is imperative.MethodsThe datasets used in this study were derived from the Gene Expression Omnibus (GEO) database. We used GSE188427 dataset as the training set to screen for biomarkers. Biomarkers of EPR were screened by Weighted Gene Co-expression Network Analysis (WGCNA), three machine-learning algorithms (LASSO regression, Random Forest, XGBoost), and other comprehensive bioinformatics analysis techniques. To evaluate the diagnostic value of these biomarkers, multiple external and internal datasets were employed as validation sets. Next, an examination was performed to investigate the relationship between the screened biomarkers and the infiltration of immune cells. Furthermore, an investigation was carried out to identify potential small molecule compounds that interact with selected diagnostic markers. Finally, we confirmed that the expression levels of the selected biomarkers exhibited a significant increase following RSV infection, and they were further identified as having antiviral properties.ResultsThe study found that lymphocyte antigen 6E (LY6E) and Transcobalamin-2 (TCN2) are two biomarkers with diagnostic significance in EPR. Analysis of immune cell infiltration showed that they were associated with activation of multiple immune cells. Furthermore, our analysis demonstrated that small molecules, 3ʹ-azido-3ʹ-deoxythymine, methotrexate, and theophylline, have the potential to bind to TCN2 and exhibit antiviral properties. These compounds may serve as promising therapeutic agents for the management of pediatric RSV infections. Additionally, our data revealed an upregulation of LY6E and TCN2 expression in PBMCs from patients with RSV infection. ROC analysis indicated that LY6E and TCN2 possessed diagnostic value for RSV infection. Finally, we confirmed that LY6E and TCN2 expression increased after RSV infection and further inhibited RSV infection in A549 and BEAS-2B cell lines. Importantly, based on TCN2, our findings revealed the antiviral properties of a potentially efficacious compound, vitamin B12.ConclusionLY6E and TCN2 are potential peripheral blood diagnostic biomarkers for pediatric RSV infection. LY6E and TCN2 inhibit RSV infection, indicating that LY6E and TCN2 are potential therapeutic target for RSV infection.

Hsa_circ_0001776 targeting miR-1265 regulates the development of lung squamous cell carcinoma and clinical significance

Objective: To further explore the role and mechanism of hsa_circ_0001776 and mir-1265 in lung squamous carcinoma by verifying the expression level of hsa_circ_0001776 in plasma, tissues, and cells of lung squamous carcinoma. Methods: Plasma was collected from patients with lung squamous carcinoma treated at Tangshan People's Hospital and healthy individuals from 2020 to 2022. Lung squamous carcinoma tissue microarrays purchased from Shanghai Xinchao Biotechnology Company in 2022. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect the expression of hsa_circ_0001776 in lung squamous carcinoma plasma, tissues, and cells, and fluorescence in situ hybridization was used to verify the expression of hsa_circ_0001776 in lung squamous carcinoma. The localization of hsa_circ_0001776 in NCI-H1703 was verified by fluorescence in situ hybridization. The lung squamous carcinoma cells NCI-H1703 and NCI-H226 were cultured in vitro and divided into the circ-negative control (NC) group, hsa_circ_0001776 overexpression group, miR-NC group, miR-1265 mimic group, hsa_circ_0001776+miR-NC group, and hsa_circ_0001776+miR-1265 mimic group.The cell proliferation, motility and apoptosis were detected by the cell counting kit-8 (CCK-8) method, clone formation, Transwell invasion and migration, and scratch assay, and flow cytometry, respectively. The downstream of hsa_circ_0001776 was predicted by circular RNA interactome website, and the interaction between hsa_circ_0001776, miR-1265 was further determined by dual luciferase reporter gene assay, and nude mice subcutaneous tumorigenesis assay detected the growth of transplanted tumors. Results: Fluorescence in situ hybridization results showed that the fluorescence intensity of hsa_circ_0001776 in lung squamous carcinoma tissues was lower than that in paracancerous tissues, and the fluorescence intensity of miR-1265 in lung squamous carcinoma tissues was higher than that in paracancerous tissues (both P＜0.05). The expression level of hsa_circ_0001776 in the plasma of lung squamous carcinoma patients was lower than that in the plasma of healthy people, and the expression level of miR-1265 was higher than that in the plasma of healthy people (both P＜0.05). The expression levels of hsa_circ_0001776 in lung squamous carcinoma cells NCI-H1703, NCI-H226 and SK-MES-1 were lower than that in bronchial epithelial cells BEAS-2B (all P＜0.05), and the relative expression levels of miR-1265 in NCI-H1703 and NCI-H226 were higher than that in human bronchial epithelial cells BEAS -2B (all P＜0.05). The expression of hsa_circ_0001776 was correlated with age, lymph node metastasis, clinical stage, and tumor stage in patients with lung squamous carcinoma (all P＜0.05). Fluorescence in situ hybridization results showed that hsa_circ_0001776 was mainly expressed in the cytoplasm. The results of dual-luciferase reporter assay showed complementary binding of miR-1265 to hsa_circ_0001776. The absorbance values of the hsa_circ_0001776 overexpression group in NCI-H1703 and NCI-H226 cells were lower than that of the circ-NC group (P＜0.05). The number of cell clones in the hsa_circ_0001776 overexpressed group was (52±3) and (53±4), the number of migrating cells was (476±17) and (113±7), the number of invading cells was (100±2) and (184±2), and the cell migration rate was (25.00±4.36)% and (36.02±5.55)%, which were lower than those of the circ-NC group [(104±4) and (106±2), (783±29) and (517±16), (657±45) and (473±9), (48.95±8.69)% and (48.70±1.57)%, all P＜0.05]. The apoptosis rates in the overexpression hsa_circ_0001776 group were (24.77±2.303)% and (19.67±1.16)%, respectively, both higher than those in the circ-NC group [(11.83±1.15)% and (9.50±0.66)%, respectively, both P＜0.05]. MiR-1265 mimic group had a higher apoptotic rate in the NCI-H1703 and NCI-H226 than those of the miR-NC groups (P＜0.05). miR-1265 mimic group had (56±13) and (51±8) cell clones, (556±13) and (405±6) migrating cells, (486±6) and (359±7) invading cells, cell migration rates of (68.56±5.51)%, (81.74±8.04)%, were higher than those of miR-NC group [(31±4) and (21±8), (154±19) and (186±5), (227±6) and (176±7), (25.83±4.26)% and (53.12±4.14) %, all P＜0.05]. The apoptotic rates in the miR-1265 mimic group were (11.83±2.55)% and (17.50±1.05)%, respectively, which were lower than those in the miR-NC group [(32.67±4.44)% and (39.90±2.88)%, respectively, both P<0.05]. The absorbance values of NCI-H1703 and NCI-H226 in the overexpression of hsa_circ_0001776+miR-1265 mimic group were higher than those of the overexpression of hsa_circ_0001776+miR-NC group (P<0.05). The overexpression of hsa_circ_0001776+miR-1265 mimic group had (128±15) and (133±8) cell clones, (623±10) and (310±7) migrating cells, (643±16) and (420±7) invading cells, (66.39±4.46)% cell migration rate and (68.60±3.53)%, were higher than those of the hsa_circ_0001776+miR-NC group [(86±7) and (80±16), (380±11) and (115±5), (152±7) and (94±4), respectively, (31.41±5.91)% and (30.94±0.67)%, all P＜0.05]. The apoptotic rates in the overexpression of hsa_circ_0001776+miR-1265 mimic group were (19.27±0.15)% and (11.53±0.75)%, respectively, both lower than those in the overexpression of hsa_circ_0001776+miR-NC group [(27.77±1.29)% and (18.43±0.71)%, both P＜0.05]. The results of the subcutaneous tumorigenesis assay in nude mice showed that the volume of tumors in the overexpression of hsa_circ_0001776 group was lower than that in the circ-NC group (P＜0.05). Conclusion: hsa_circ_0001776 is downregulated in lung squamous cell carcinoma, and hsa_circ_0001776 can inhibit the development of lung squamous cell carcinoma by targeting miR-1265.

Study on the molecular mechanism of autophagy and apoptosis induced by ultrafine carbon black in human bronchial epithelial cells and the intervention effect of N-acetylcysteine

Objective: To investigate the molecular mechanism of autophagy and apoptosis induced by ultrafine carbon black in human bronchial epithelial cells (BEAS-2B cells), and to study the intervention effect and mechanism of N-acetylcysteine (NAC) on ultrafine carbon black-induced oxidative damage in BEAS-2B cells. Methods: In March 2023, BEAS-2B cells were used as research object, an in vitro airway model exposed to ultrafine carbon black was constructed. A control group and three carbon black exposure groups (50, 100, 200 μg/ml) were set up, and the cells were treated with corresponding concentrations of ultrafine carbon black for 24 hours. In addition, the experiment was divided into control group, NAC+ control group, 100 μg/ml carbon black exposure group and NAC+ exposure group. The corresponding groups were treated with 2 mmol/L NAC for 1 h and 100 μg/ml ultrafine carbon black for 24 h, respectively. Cell viability was measured by CCK-8 assay. Intracellular reactive oxygen species (ROS) level was detected by chemical fluorescence method. The activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), as well as the content of malondialdehyde (MDA) were detected by colorimetry. The mRNA and protein expressions of autophagy-related genes[Atg5, Atg7, Beclin1, microtubule-associated protein light chain 3B (LC3B), p62 and lysosome-associated membrane protein 2 (LAMP2) ] and apoptosis-related genes [B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), Caspase3, Caspase9 and poly (ADP-ribose) polymerase 1 (PARP1) ] were determined by fluorescence quantitative PCR and Western blot. Cell apoptosis was determined by flow cytometry. Results: Compared with the control group, the relative survival rates of BEAS-2B cells in 50, 100, 200 μg/ml carbon black exposure groups were significantly decreased, the levels of ROS and MDA were significantly increased, and the activities of SOD, GSH-Px and CAT were significantly decreased (P<0.05). The relative survival rate, ROS and MDA levels, SOD, GSH-Px and CAT activities were significantly correlated with the exposure dose of ultrafine carbon black (r(s)=-0.755, 0.826, 0.934, -0.810, -0.880, -0.840, P<0.05). Compared with the control group, the relative expression levels of Atg5, Atg7, Beclin1, LC3B, p62, LAMP2, Bax, Caspase3, Caspase9, PARP1 mRNA and Atg5, Atg7, Beclin1, LC3BⅡ, p62, LAMP2, Bax, cleaved Caspase3 (C-Caspase3), cleaved Caspase9 (C-Caspase9), cleaved PARP1 (C-PARP1) protein and the ratio of LC3BⅡ/LC3BⅠ in 50, 100 and 200 μg/ml carbon black exposure groups were significantly increased, while the relative expression levels of Bcl-2 mRNA and protein were significantly decreased (P<0.05). The changes of the above indexes were significantly correlated with the exposure dose of carbon black (r(s)=0.892, 0.879, 0.944, 0.892, 0.828, 0.880, 0.814, 0.794, 0.931, 0.918, 0.813, 0.866, 0.774, 0.695, 0.918, 0.761, 0.794, 0.944, 0.833, 0.866, 0.905, -0.886, -0.748, P<0.05). Compared with 100 μg/ml carbon black exposure group, the relative survival rate, the activities of SOD, GSH-Px and CAT in NAC+exposure group were significantly increased, while the levels of ROS and MDA were significantly decreased, and the relative expression levels of LC3B, p62 and Caspase3 mRNA and protein as well as the ratio of LC3BⅡ/LC3BⅠ were significantly decreased, and the differences were statistically significant (P<0.05). Compared with the control group, the apoptosis rates of BEAS-2B cells in 50, 100, 200 μg/ml carbon black exposure groups were significantly increased (P<0.05), and there was a significant positive correlation between ultrafine carbon black exposure dose and cell apoptosis rate (r(s)=0.944, P<0.05). While compared with 100 μg/ml carbon black exposure group, the apoptosis rate of NAC+exposure group was significantly decreased, and the difference was statistically significant (P<0.05) . Conclusion: Cell autophagy and apoptosis may be important pathophysiological mechanisms of ultrafine carbon black-induced oxidative damage in BEAS-2B cells. NAC can alleviate the occurrence of BEAS-2B cell damage caused by ultrafine carbon black by regulating oxidative stress and the cascading autophagy and apoptosis pathways.

HMGB1 derived from lung epithelial cells after cobalt nanoparticle exposure promotes the activation of lung fibroblasts

We have previously demonstrated that exposure to cobalt nanoparticles (Nano-Co) caused extensive interstitial fibrosis and inflammatory cell infiltration in mouse lungs. However, the underlying mechanisms of Nano-Co-induced pulmonary fibrosis remain unclear. In this study, we investigated the role of high-mobility group box 1 (HMGB1) in the epithelial cell-fibroblast crosstalk in Nano-Co-induced pulmonary fibrosis. Our results showed that Nano-Co exposure caused remarkable production and release of HMGB1, as well as nuclear accumulation of HIF-1α in human bronchial epithelial cells (BEAS-2B) in a dose- and a time-dependent manner. Pretreatment with CAY10585, an inhibitor against HIF-1α, significantly blocked the overexpression of HMGB1 in cell lysate and the release of HMGB1 in the supernatant of BEAS-2B cells induced by Nano-Co exposure, indicating that Nano-Co exposure induces HIF-1α-dependent HMGB1 overexpression and release. In addition, treatment of lung fibroblasts (MRC-5) with conditioned media from Nano-Co-exposed BEAS-2B cells caused increased RAGE expression, MAPK signaling activation, and enhanced expression of fibrosis-associated proteins, such as fibronectin, collagen 1, and α-SMA. However, conditioned media from Nano-Co-exposed BEAS-2B cells with HMGB1 knockdown had no effects on the activation of MRC-5 fibroblasts. Finally, inhibition of ERK1/2, p38, and JNK all abolished MRC-5 activation induced by conditioned media from Nano-Co-exposed BEAS-2B cells, suggesting that MAPK signaling might be a key downstream signal of HMGB1/RAGE to promote MRC-5 fibroblast activation. These findings have important implications for understanding the pro-fibrotic potential of Nano-Co.

DMRT3-mediated lncRNA OIP5-AS1 promotes the pyroptosis of bronchial epithelial cells by binding with EIF4A3 to enhance YAP mRNA stability.

Asthma is featured by persistent airway inflammation. Long noncoding RNAs (lncRNAs) are reported to play critical roles in asthma. However, the function of Opa interacting protein 5-antisense 1 (OIP5-AS1) in pyroptosis during the development of asthma remains unexplored. The blood samples of asthma patients (n = 32) as well as the baseline characteristics of asthma patients or healthy people were collected. An in vivo model of asthma was established using house dust mites (HDM). To mimic asthma in vitro, BEAS-2B cells were treated with HDM. Cell pyroptosis and apoptosis were examined by flow cytometry. The levels of interleukin-1 beta (IL-1β) and interleukin-18 (IL-18) were detected by enzyme-linked immunosorbent assay (ELISA). The binding among messenger RNAs (mRNAs) was assessed by chromatin immunoprecipitation (ChIP), dual luciferase report assay, RNA immunoprecipitation (RIP), co-immunoprecipitation (Co-IP), and RNA pull-down assay, respectively. The cellular localization was observed by fluorescence in situ hybridization (FISH) staining. The level of OIP5-AS1 was upregulated in asthma patients. HDM induced pyroptosis and increased the levels of IL-18, IL-1β, and lactate dehydrogenase (LDH) in BEAS-2B cells, which was obviously reversed by OIP5-AS1 knockdown. Consistently, the expressions of NOD-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), c-caspase 1, and pyroptosis-related gasdermin D-1 (GSDMD-1) in BEAS-2B cells were upregulated by HDM treatment, while these phenomena were partially abolished by silencing of OIP5-AS1. Moreover, HDM promoted the progression of asthma in vivo, which was rescued by the downregulation of OIP5-AS1. OIP5-AS1 silencing decreased HDM-induced cell pyroptosis by inactivation of NLRP3. More importantly, OIP5-AS1 promoted the mRNA stability of yes-associated protein (YAP) via binding with eukaryotic translation initiation factor 4A3 (EIF4A3), and OIP5-AS1 was transcriptionally upregulated by doublesex and mab-3 related transcription factor 3 (DMRT3). DMRT3-mediated OIP5-AS1 aggravated the progression of asthma by mediation of the EIF4A3/YAP axis, which might provide a new therapeutic strategy against asthma.

Novel DNA Repair Inhibitors Targeting XPG to Enhance Cisplatin Therapy in Non-Small Cell Lung Cancer: Insights from In Silico and Cell-Based Studies.

NSCLC is marked by low survival and resistance to platinum-based chemotherapy. The XPG endonuclease has emerged as a promising biomarker for predicting the prognosis of cisplatin-treated patients and its downregulation having been reported to increase cisplatin efficacy. This study presents an integrated strategy for identifying small molecule inhibitors of XPG to improve cisplatin therapy in NSCLC. A structure-based virtual screening approach was adopted, including a structural and physicochemical analysis of the protein, and a library of small molecules with reported inhibitory activities was retrieved. This analysis identified Lys84 as a crucial residue for XPG activity by targeting its interaction with DNA. After molecular docking and virtual screening calculations, 61 small molecules were selected as potential XPG inhibitors, acquired from the ChemBridge database and then validated in H1299 cells, a NSCLC cell line exhibiting the highest ERCC5 expression. The MTS assay was performed as a first screening approach to determine whether these potential inhibitors could enhance cisplatin-induced cytotoxicity. Overall, among the eight compounds identified as the most promising, three of them revealed to significantly increase the impact of cisplatin. The inherent cytotoxicity of these compounds was further investigated in a non-tumoral lung cell line (BEAS-2B cells), which resulted in the identification of two non-cytotoxic candidates to be used in combination with cisplatin in order to improve its efficacy in NSCLC therapy.

Pyroptosis inhibition alleviates acute lung injury via E-twenty-six variant gene 5-mediated downregulation of gasdermin D

BackgroundAcute lung injury (ALI) is a life-threatening condition characterized by excessive pulmonary inflammation, yet its precise pathophysiology remains elusive. Pyroptosis, a programmed cell death mechanism controlled by gasdermin D (GSDMD), has been linked to the etiology of ALI. This study investigated the regulatory functions of the transcription factor E-twenty-six variant gene 5 (ETV5) and GSDMD in ALI. MethodsLipopolysaccharide (LPS) was used to treat BEAS-2B cells (50 mmol/mL) and establish an LPS-induced mouse model of ALI (by intratracheal administration, 3 mg/kg). Protein-protein docking, immunofluorescence analysis, western blotting, real-time quantitative polymerase chain reaction, and dual-luciferase reporter gene assay were used to examine ETV5-mediated negative feedback regulation of GSDMD and its effects on pyroptosis and ALI. ResultsOur results showed that the physiological function of ETV5 was reduced by its downregulated expression, which impeded its nuclear translocation in ALI mice. Increased pyroptosis and enhanced production of inflammatory cytokines were associated with LPS-induced ALI. ETV5 overexpression in LPS-treated BEAS-2B cells decreased the expression of total and membrane-bound GSDMD, negatively regulated GSDMD, and prevented pyroptosis. The expression of inflammatory cytokines was subsequently reduced due to this inhibition, which, in turn, reduced ALI. Molecular docking analysis and dual-luciferase reporter gene assay results indicated a direct interaction between ETV5 and GSDMD, which inhibited GSDMD production. ConclusionOur results indicate that ETV5 inhibits pyroptosis, decreases the expression of inflammatory cytokines, and negatively regulates GSDMD expression to ameliorate ALI symptoms.

Hydramethylnon induces mitochondria-mediated apoptosis in BEAS-2B human bronchial epithelial cells

Typically used household chemicals comprise numerous compounds. Determining mixture toxicity, as observed when using household chemicals containing multiple substances, is of considerable importance from a regulatory perspective. Upon examining the toxic effects of household chemical mixtures, we observed that hydramethylnon combined with tetramethrin resulted in synergistic toxicity. To determine the unknown toxicity mechanism of hydramethylnon, which carries the risk of inhalation exposure when using household chemicals, we conducted a further investigation using BEAS-2B cells, a human bronchial epithelial cell line. Hydramethylnon-induced cytotoxicity was determined following 24 and 48 h of exposure using the water-soluble tetrazolium 1 and lactate dehydrogenase assays. To elucidate the toxicity mechanism, we utilized flow cytometry and measured the levels of apoptosis-related proteins and caspase activities. Given that hydramethylnon, as an insecticide, disrupts the mitochondrial electron transfer chain, we analyzed the relevant mechanisms, including mitochondrial superoxide levels as well as the mitochondrial membrane potential (MMP). Hydramethylnon dose-dependently induced BEAS-2B cell apoptosis via the intrinsic pathway. Furthermore, it significantly increased mitochondrial superoxide levels and disrupted the MMP. Pre-treatment with a caspase inhibitor (Z-DEVD-FMK) confirmed that hydramethylnon induced caspase-dependent apoptosis. Apoptosis, a key event in the toxicological process of chemicals, can lead to lung diseases, including fibrosis and cancer. The results of the present study suggest a mechanism of toxicity of hydramethrylnon, an organofluorine biocide whose toxicity has been little studied, to the lung epithelium. Considering the potential risks associated with inhalation exposure, these results highlight the need for careful management and regulation of hydramethylnon.

Interleukin-9 promotes EMT-mediated PM2.5-induced pulmonary fibrosis by activating the STAT3 pathway.

This study investigated the impact of PM2.5 on promoting EMT in PM2.5-induced pulmonary fibrosis (PF) development and explored molecular mechanisms of the IL-9/STAT3/Snail/TWIST1 signaling pathway in PF owing to PM2.5. Four groups of male SD rats were formed: control (0mg/kg.bw), low (1mg/kg.bw), medium (5mg/kg.bw), and high-dose (25mg/kg.bw) PM2.5 groups. Experimental rats were subjected to PM2.5 exposure via intratracheal instillation, given once weekly for 16weeks. 24 h after the final exposure, blood, BALF, and lung tissues were collected. Pulmonary epithelial cells underwent cultivation and exposure to varying PM2.5 concentrations with/without inhibitors for 24h, after which total protein was extracted for relevant protein assays. The findings demonstrated that PM2.5 damaged lung tissue to different degrees and led to PF in rats. Rats subjected to PM2.5 exposure exhibited elevated concentrations of IL-9 protein in both serum and BALF, and elevated levels of IL-9 and its receptor, IL-9R, in lung tissues, compared to control counterparts. Furthermore, PM2.5-exposed groups demonstrated significantly augmented protein levels of p-STAT3, Snail, TWIST1, Vimentin, COL-I, and α-SMA, while displaying notably diminished levels of E-Cadherin compared to control group. The same findings were observed in PM2.5-treated cells. In BEAS-2B cells co-treated with Stattic (STAT3 inhibitor) and PM2.5, the opposite results occurred. Similar results were obtained for cells co-treated with IL-9-neutralizing antibody and PM2.5. Our findings suggest PM2.5 mediates PF development by promoting IL-9 expression, leading to STAT3 phosphorylation and upregulation of Snail and TWIST1 expression, triggering EMT occurrence and progression in lung epithelial cells.

Exosome-transmitted circ_0004664 suppresses the migration and invasion of cadmium-transformed human bronchial epithelial cells by regulating PTEN expression via miR-942-5p

Exosomes play a crucial role in regulating extracellular communication between normal and cancer cells within the tumor microenvironment, thereby affecting tumor progression through their cargo molecules. However, the specific impact of exosomal circular RNAs (circRNAs) on the development of cadmium-induced carcinogenesis remains unclear. To address this, we investigated whether exosomes derived from normal human bronchial epithelial BEAS-2B (N–B2B) cells could transmit circRNA to cadmium-transformed BEAS-2B (Cd–B2B) cells and the potential effects on Cd–B2B cells. Our findings demonstrated a significant downregulation of circ_0004664 in Cd–B2B cells compared to N–B2B cells (P < 0.01). Overexpression of circ_0004664 in Cd–B2B cells led to a significant inhibition of cell migration and invasion (P < 0.01 or P < 0.05). Furthermore, N–B2B cells could transfer circ_0004664 into recipient Cd–B2B cells via exosomes, subsequently inhibiting cell migration and invasion (P < 0.05 or P < 0.01). Mechanistic investigations revealed that exosomal circ_0004664 functioned as a competitive endogenous RNA for miR-942-5p, resulting in an upregulation of PTEN (P < 0.05). Our study highlights the involvement of exosomal circ_0004664 in cell-cell communication during cadmium carcinogenesis, providing a novel insight into the role of exosomal circRNA in this process.

Repeated radon exposure induced ATM kinase-mediated DNA damage response and protective autophagy in mice and human bronchial epithelial cells.

Radon ( 222 Rn) is a naturally occurring radioactive gas that has been closely linked with the development of lung cancer. In this study, we investigated the radon-induced DNA strand breaks, a critical event in lung carcinogenesis, and the corresponding DNA damage response (DDR) in mice and human bronchial epithelial (BEAS-2B) cells. Biomarkers of DNA double-strand breaks (DSBs), DNA repair response to DSBs, ataxia-telangiectasia mutated (ATM) kinase, autophagy, and a cell apoptosis signaling pathway as well as cell-cycle arrest and the rate of apoptosis were determined in mouse lung and BEAS-2B cells after radon exposure. Repeated radon exposure induced DSBs indicated by the increasing expressions of γ-Histone 2AX (H2AX) protein and H2AX gene in a time and dose-dependent manner. Additionally, a panel of ATM-dependent repair cascades [i.e. non-homologous DNA end joining (NHEJ), cell-cycle arrest and the p38 mitogen activated protein kinase (p38MAPK)/Bax apoptosis signaling pathway] as well as the autophagy process were activated. Inhibition of autophagy by 3-methyladenine pre-treatment partially reversed the expression of NHEJ-related genes induced by radon exposure in BEAS-2B cells. The findings demonstrated that long-term exposure to radon gas induced DNA lesions in the form of DSBs and a series of ATM-dependent DDR pathways. Activation of the ATM-mediated autophagy may provide a protective and pro-survival effect on radon-induced DSBs.

PM2.5 Induces Pyroptosis via Activation of the ROS/NF-κB Signaling Pathway in Bronchial Epithelial Cells.

Background and Objectives: Fine particulate matter, PM2.5, 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 PM2.5 on pyroptosis, especially in airway epithelium. We investigated whether PM2.5-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 PM2.5 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: PM2.5 induced pyroptotic cell death, accompanied by LDH (Lactate dehydrogenase) release and increased uptake of propidium iodide in a dose-dependent manner. PM2.5 activated the NLRP3-casp1-gasdermin D pathway, with resulting secretions of the proinflammatory cytokines IL-1β and IL-18. The pyroptosis activated by PM2.5 was alleviated significantly by NLRP3 inhibitor. In PM2.5-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 PM2.5 exposure, indicating that the ROS/NF-κB pathway is involved in PM2.5-induced pyroptosis. Conclusions: These findings show that PM2.5 exposure can cause cell injury by NLRP3-inflammasome-mediated pyroptosis by upregulating the ROS/NF-κB pathway in airway epithelium.