Research progress on mechanisms of malignant transformation of lung epithelial cells induced by PM2.5 exposure / 环境与职业医学

Fine particulate matter (PM2.5) has attracted more and more attention in the field of environmental pollution and public health. Previous studies have found that PM2.5 can be inhaled and deposit in the airway and alveoli, and even spread to the whole-body tissues and organs through blood, resulting in various toxic effects. The malignant transformation of lung epithelial cells associated with long-term exposure to PM2.5 may play an important role in the occurrence and development of lung cancer. This paper reviewed recent studies on the mechanisms of malignant transformation of lung epithelial cells associated with PM2.5 exposure, and discussed the main biological mechanisms, including epigenetics, tumor microenvironment, and other biological pathways. Besides, the potential research directions of malignant transformation of lung epithelial cells associated with PM2.5 exposure were proposed. This work aims to provide a scientific basis and reference for public health management and air quality assessment.

Genomics study of human lung epithelial cells against new coronavirus SARS-CoV-2 infection / 西安交通大学学报(医学版)

【Objective】 Based on the high-throughput sequencing data of the whole genome， genomics and bioinformatics analyses were made to analyze the gene expression changes in the epithelial cells of the lung tissue from patients with coronavirus disease 2019 （COVID-19）， and explore the effects of the new coronavirus SARS-CoV-2 on human lungs. This study can provide a theoretical basis for the exploration of SARS-CoV-2 on the pathogenesis of lung tissue. 【Methods】 The public data set GSE160435 was retrieved. The data were analyzed by Network analyst， Cytoscape 3.7.2， String 11.0， and other software. The differentially expressed genes were screened， gene function （Gene Ontology， GO） and signal pathway KEGG （Kyoto Encyclopedia of Genes and Genomes） enrichment analysis were carried out. We established the Protein-protein Interactions Network （PPI）， PPI of lung tissue-specific DEGs， DEG microRNA regulatory network， Transcription Factor （TF）-DEG regulatory network， and environmental chemicals DEGs regulatory network. 【Results】 We found 324 DEGs in the lung epithelial cells of patients with COVID-19， of which 112 （34.57%） were upregulated and 212 （65.43%） were downregulated. Enrichment analysis showed that DEGs were mainly involved in biological processes such as virus-related defense response， mainly involved in protein digestion and absorption， anti-human papillomavirus infection and other signaling pathways. Specific PPI network closely related to DEGs and lung tissue showed that PDGFRB and KIT were core proteins； hsa-mir-340 had targeted interaction with DEGs. It indicated that HOXB4， ISG15 and other related genes were regulated by transcription factors； DEGs interacted with environmental chemicals such as nickel and estradiol. 【Conclusion】 The gene expression pattern of lung epithelial cells in lung tissue of COVID-19 patients has changed significantly. Proteins or genes such as PDGFRB， MMP9 and KIT may play a vital role in the defense immunity of lung tissue. Micro-RNA， TF， signaling pathway molecules， environmental chemicals， and lung tissue-specific genes also play a role in the above-mentioned process. This study provides new ideas for exploring the pathogenic mechanism of SARS-CoV-2 on lung tissue and formulating clinical prevention， diagnosis and treatment measures.

Interfering with glutathione S-transferase P1 induces lung cell damage under irradiation conditions / 中华放射肿瘤学杂志

Objective To investigate the association and mechanism between glutathione S-transferase P1(GSTP1) and radiation-induced lung injury.Methods Two effective GSTP1 siRNAs were designed and synthesized.The normal lung epithelial cell line BEAS-2B cells were transfected with GSTP1 siRNA (experimental group,siRNA-1,siRNA-2) and negative control siRNA (negative control group,NC).Western blot was performed to detect the expression levels of GSTP1 protein and EMT-related proteins.CDNB was adopted to evaluate the activity of GSTs.DCFH-DA probe was used for incubation.Flow cytometry was conducted to detect the median fluorescence intensity (MFI) and cellular apoptosis.Annexin-v/PI staining was utilized for incubation.MTT assay was performed to measure the proliferation of BEAS-2B,and the growth curve was drawn based on the results.Results After radiation,compared with the NC group,the ROS level and MFI were significantly higher in experimental group (6774.66±399.60 vs.8759.00±256.96 vs.9967.67±735.11,P＜0.05).In the experimental group,the percentage of cellular apoptosis was remarkably higher than that in the NC group (12.3± 1.16 vs.17.38± 1.65 vs.22.88± 1.20,P＜0.05).MTT assay demonstrated that the OD values in the experimental group were significantly lower than that in the NC group everyday.Further more,the level of EMT process is higher in the experimental group.Conclusions Interfering with the GSTP1 expression in lung epithelial cells can increase the intracellular ROS level,increase the percentage of cellular apoptosis,and reduce the cell proliferation rate following γ-radiation.Besides,it can also promote the epithelial mesenchymal transition in lung epithelial cells.The down-regulation of GSTP1 protein expression level probably aggravates the radiationinduced lung cell injury and promotes the epithelial mesenchymal transition.

The effect of hydrochloric acid stimulation and mechanical stretch on epithelial-mesenchymal transition in ;human lung epithelial cells / 中华危重病急救医学

Objective To investigate the effect of hydrochloric acid (HCl) stimulation and mechanical stretch on epithelial-mesenchymal transition (EMT) and hyaluronan (HA) production in human lung epithelial cells. Methods Human lung epithelial cell line BEAS-2B was cultured in vitro, which was divided into phosphate-buffer saline (PBS) + static group, HCl + static group, PBS + stretch group, and HCl + stretch group respectively in the logarithmic phase. The BEAS-2B cells in two stretching groups were challenged by cyclic stretch with 20% amplitude, frequency of 0.33 Hz, sine wave of the FX-5000T system for 48 hours. The morphology changes in cells before and after stretch were observed with inverted microscope. The protein expressions of epithelial markers E-cadherin and cytokeratin-8 (CK-8) as well as mesenchymal markers vimentin and α-smooth muscle actin (α-SMA) were determined by Western Blot. The secretion of HA was determined by enzyme linked immunosorbent assay (ELISA). Results ① It was shown by microscopic observation that BEAS-2B cells displayed cobblestone morphology, linked closely and cell polarity in PBS + static group, which did not change obviously after HCl stimulation alone. Given purely mechanical stretch after 48 hours, the cells morphology changed from cobblestone shape into long spindle, and increased intercellular space obviously. Double hit of HCl and stretch changed the cells morphology more significantly. ② It was shown by Western Blot that compared with the PBS + static group, HCl alone or combined with purely mechanical stretch after 48 hours, the expressions of E-cadherin and CK-8 were decreased, while those of vimentin and α-SMA were increased, and it was more pronounced in HCl + stretch group [the expression quantity (gray value) as base 1 in PBS + static group, E-cadherin: 0.16±0.08 vs. 1, CK-8: 0.10±0.03 vs. 1, vimentin: 3.35±0.38 vs. 1, α-SMA: 3.10±0.45 vs. 1, all P < 0.01]. ③ It was shown by ELISA that both HCl stimulation and stretch could induce BEAS-2B cells secreting HA as compared with PBS + static group (μg/L: 55.763±0.687, 63.005±0.493 vs. 49.876±1.867), and the production of HA increased more remarkably after double hit (μg/L: 78.220±1.085 vs. 49.876±1.867, P < 0.01). Conclusions Both HCl and mechanical stretch could induce EMT and increase HA secretion in human lung epithelial cells in vitro. Double hit of HCl stimulation and mechanical stretch induced EMT apparently, and further increased the production of HA.

Licochalcone A protects against cigarette smoke-mediated acute lung injury in mice by suppressing ERK1/2/NF-κB pathways / 中国药理学通报

Aim To explore the protective roles of lic-ochalcone A ( LA) on mice with cigarette smoke-medi-ated acute lung injury and the related mechanisms. Methods In vivo: Mice were exposed to cigarette smoke ( CS) to establish acute lung injury model. The bronchoalveolar lavage fluid ( BALF ) was conducted for cell counting. The mRNA and protein expression of keratinocyte-derived chemokine ( KC ) , tumor necrosis factor alpha ( TNF-α) , interleukin 1β ( IL-1β) and matrix metalloproteinases ( MMP)-9 in lungs were de-termined. The myeloperoxidase ( MPO ) , superoxide dismutase ( SOD ) activities and glutathione ( GSH ) levels in lungs were quantified. The paraffin sections of lungs were prepared and stained with HE. In vitro:Human lung epithelial cells (BEAS-2B) were exposed to cigarette smoke extract ( CSE ) , which induced cell injury. The releases of interleukin 8 (IL-8) and MMP-9 were assessed. The phosphorylation of mitogen-acti-vated protein kinases ( MAPKs, including ERK1/2, p38 and JNK ) and nuclear factor-κB ( NF-κB ) p65 protein were analyzed by Western blot. Results In vi-vo: The accumulation of inflammatory cells was lower in LA groups than that in model group. In comparison with normal control group, the mRNA and protein lev-els of KC, TNF-α, IL-1βand MMP-9 were significant-ly increased in model group. Following treatment with LA, the above indicators were significantly decreased as compared to model group. In the CS-exposed mice, the MPO activity in lungs was significantly increased, meanwhile the SOD activity and GSH level were signif-icantly decreased compared with the air-exposed ani-mals. CS-induced activity of MPO was significantly in-hibited, which were accompanied by increases in SOD and GSH levels by LA. In vitro: CSE-induced mRNA levels of IL-8 and MMP-9 were significantly inhibited by LA at 2 . 5 and 5 μmol · L-1 . The CSE-induced phosphorylation of ERK1/2 and nucleus NF-κB p65 protein expression were prevented by pretreatment with LA. Conclusions LA has protective effects on CS-ex-posed acute lung injury in mice by preventing CS-in-duced pulmonary inflammation, oxidative stress and protease rise. The exploration of the mechanisms sug-gests that LA exerts protective effects via suppressing ERK1/2/NF-κB pathways.

Airborne agricultural particulate matter induces inflammatory cytokine secretion by respiratory epithelial cells: Mechanisms of regulation by eicosanoid lipid signal mediators.

The purpose of this study was to elucidate the mechanism of the airborne poultry dust (particulate matter, PM)-induced respiratory tract inflammation, a common symptom in agricultural respiratory diseases. The study was based on the hypothesis that poultry PM would induce the release of inflammatory cytokine interleukin-8 (IL-8) by respiratory epithelial cells under the upstream regulation by cytosolic phospholipase A2 (cPLA2) activation and subsequent formation of cyclooxygenase (COX)- and lipoxygenase (LOX)-catalyzed arachidonic acid (AA) metabolites (eicosanoids). Human lung epithelial cells (A549) in culture were treated with the poultry PM (0.1-1.0 mg) for different lengths of time, following which PLA2 activity, release of eicosanoids and secretion of IL-8 in cells were determined. Poultry PM (1.0 mg/ml) caused a significant activation of PLA2 in a time-dependent manner (15-60 min), which was significantly attenuated by the calcium-chelating agents, cPLA2-specific inhibitor (AACOCF3) and antioxidant (vitamin C) in A549 cells. Poultry PM also significantly induced the release of COX- and LOX-catalyzed eicosanoids (prostaglandins, thromboxane A2 and leukotrienes B4 and C4) and upstream activation of AA LOX in the cells. Poultry PM also significantly induced release of IL-8 by the cells in a dose- and time-dependent manner, which was significantly attenuated by the calcium chelating agents, antioxidants and COX- and LOX-specific inhibitors. The current study for the first time revealed that the poultry PM-induced IL-8 release from the respiratory epithelial cells was regulated upstream by reactive oxygen species, cPLA2-, COX- and LOX-derived eicosanoid lipid signal mediators.

Comparative study of PM2.5 - and PM10 - induced oxidative stress in rat lung epithelial cells

Accurate estimation of the exposure-response relationship between ambient urban particulate matters (PM) and public health is important for regulatory perspective of ambient urban particulate matters (PM). Ambient PM contains various transition metals and organic compounds. PM10 (aerodynamic diameter less than 10 microgram) is known to induce diverse diseases such as chronic cough, bronchitis, chest illness, etc. However, recent evaluation of PM2.5 (aerodynamic diameter less than 2.5 microgram) against health outcomes has suggested that the fine particles may be more closely associated with adverse respiratory health effects than particles of larger size. This study was performed to evaluate PM2.5-induced oxidative stress in rat lung epithelial cell in order to provide basic data for the risk assessment of PM2.5. PM2.5 showed higher cytotoxicity than PM10. Also, PM 2.5 induced more malondialdehyde (MDA) formation than PM10. In Hoechst 33258 dye staining and DNA fragmentation assay, apopotic changes were clearly detected in PM2.5 treated cells in compared to PM10. Expression of catalase mRNA was increased by PM2.5 rather than PM10. PM2.5 induced higher Mth1 mRNA than PM10. In pBR322 DNA treated with PM2.5, production of single strand breakage of DNA was higher than that of PM10. In Western blot analysis, PM2.5 induced more Nrf-2 protein, associated with diverse transcriptional and anti-oxidative stress enzymes, compared to PM10. Our data suggest that PM2.5 rather than PM10 may be responsible for PM-induced toxicity. Additional efforts are needed to establish the environmental standard of PM2.5.