Objective : To investigate the mechanisms of bromodomain-containing protein 4(BRD4) in TGF-β1-induced epithelial-mesenchymal transition in alveolar type II epithelial cells. Methods : MLE-12 cells were stimulated with different concentrations(5 ng/ml, 10 ng/ml) of TGF-β1 for 48 h to establish an EMT cell model. The cells were pretreated with 50 nmol/L BRD4 inhibitor JQ-1, 100 μmol/L high mobility group box 1 protein(HMGB1)inhibitor glycyrrhizin acid(GA), and 3 μg/ml rHMGB1. The experimental groups were divided as follows: control group, TGF-β1 group, JQ-1 group, JQ-1+TGF-β1 group, GA group, GA+TGF-β1 group, and JQ-1+TGF-β1+rHMGB1 group. The effect of JQ-1 on cell viability was examined using cell counting kit-8(CCK-8). The protein expression levels of CDH1, ZO-1, Vimentin, α-SMA, BRD4, HMGB1, TGF-β1, Smad2/3 and p-Smad2/3 were detected by Western blot. The cell migration ability was detected by a scratch test. Results : Compared with the control group, the levels of Vimentin and α-SMA in the TGF-β1 group increased, and the levels of CDH1 and ZO-1 protein decreased, suggesting that the EMT model was successfully established. In this model, the expression of BRD4 and HMGB1 significantly increased. Different concentrations of JQ-1 could inhibit the cell viability of MLE-12 in a concentration-dependent manner. Both JQ-1 and GA could effectively alleviate TGF-β1-induced EMT, and reduce the increase in HMGB1 expression and the activation of TGF-β1/Smad2/3 pathway caused by TGF-β1. Moreover, rHMGB1 treatment could reduce the effects of JQ-1 on EMT and the TGF-β1/Smad2/3 pathway. Additionally, both JQ-1 and glycyrrhizin could effectively decrease TGF-β1-induced cell migration, whereas rHMGB1 could alleviate the inhibitory effect of JQ-1 on the rate of cell migration. Conclusion BRD4 can regulate epithelial-mesenchymal transition in alveolar type II epithelial cells via HMGB1/TGF-β1/Smad2/3 signaling cascade, and BRD4 may be a potential target for inhibition of pulmonary fibrosis.

Objective: To explore the differential lipid metabolites in the plasma of mice with idiopathic pulmonary fibrosis(IPF). Methods : Thirty SPF C57BL/6 male mice were randomly divided into 2 groups with 15 mice in each group. The experimental groups were divided into control group and bleomycin(BLM) group. The model of idiopathic pulmonary fibrosis was induced by one-time intratracheal infusion of BLM(1 mg/kg). Hematoxylin-eosin(HE) staining was used to observe the lung histopathology. The collagen fiber deposition in lung tissue was observed by Sirius red staining. The differential lipid metabolites in plasma of IPF mice were screened and enriched by lipidomics. Results : HE staining showed that the pulmonary tissue structure was disordered, alveolar septum was broken and alveolar wall was destroyed in BLM group. Sirius red staining showed a large amount of collagen fiber deposition in the lung interstitium of BLM group. The results of lipidomics analysis showed that the lipid metabolism profile of BLM group changed, 15 differential lipid metabolites were screened out, of which 11 differential lipid metabolites were up-regulated, and 4 differential lipid metabolites were down-regulated, mainly concentrated in glycerophosphoglycerophosphates, glycerophosphocholines, steroid lactones, etc. Conclusion The lipid metabolism profile of BLM group mice changes, differential lipid metabolites such as phosphoglycolate phosphatase(PGP)(18:0/18:0), PGP(i-12:0/i-24:0), PGP(i-13:0/a-25:0), and phosphatidylcholine(PC)(18:0/14:0), PC(18:3/16:0), lysophosphatidylcholine(LPC)(16:1), and LPC(18:3) may play an important role in the progression of IPF. These findings provide a new reference for further study of the molecular mechanism of IPF, and also provide a potential new target for clinical treatment.

Objective To screen and analyze the differentially expressed genes (DEGs) related to oxidative stress in a silicosis mouse model using transcriptome sequencing technology. Methods i) A total of 30 workers without occupational dust-exposed history were selected as the control group and 17 patients with silicosis were selected as the silicosis group using a judgment sampling method. The levels of glutathione and malondialdehyde in the plasma of workers in the two groups were determined by enzyme-linked immunosorbent assay. ii) RAW264.7 cells in the logarithmic growth phase were randomly divided into the control group and the silica group, treated with 0 and 50 mg/L silica suspensions for 24 hours. Protein expression of superoxide dismutase 2 (SOD2), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in the cells was determined by Western blotting. iii) The specific pathogen free male C57BL/6 mice were randomly divided into the control group and the silicosis model group, with 10 mice in each group. Mice were exposed to 50 μL of 0.9% sodium chloride solution and silica suspension at a mass concentration of 100 g/L, respectively, using a single tracheal exposure method. After 28 days of exposure, the pathological changes of mouse lung tissues were observed. Transcriptome sequencing was used to screen DEGs in the lung tissues of the silicosis mouse model, and gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed. The expression of DEGs was verified using quantitative real-time polymerase chain reaction (qPCR). Results i) The level of malondialdehyde in the patients′ plasma was higher (P<0.01), while the level of glutathione was lower (P<0.01) in the silicosis group than that of the control group. ii) The relative expression of SOD2 protein decreased (P<0.05), while the relative expression of IL-6 and TNF-α proteins increased (all P<0.05) in the silica group of RAW264.7 cells compared with the control group. iii) The pathological results of lung tissues showed that the alveolar structure of mice was destroyed and silicotic nodules were formed in the silicosis model group. Transcriptome sequencing identified 3 703 DEGs, of which 3 199 were significantly down-regulated and 504 were significantly up-regulated. The GO enrichment analysis results showed that the DEGs were significantly enriched in biological processes such as oxidative stress, inflammation, immunity and hypoxia, with cellular components mainly located in membranes, cytoplasm, and nucleus. Molecular functions were enriched in oxidoreductase activity, protein binding, and adenosine triphosphate binding. The KEGG enrichment analysis results showed that the DEGs were mainly involved in the phosphatidylinositol 3-kinase-protein kinase B signaling pathway, cyclic adenosine monophosphate signaling pathway, chemokine signaling pathway, and apoptosis signaling pathway. A total of 28 DEGs involved in the "oxidative stress response" pathway were screened by GO enrichment analysis. The qPCR verification results showed that the relative expression of DEGs carbonic anhydrase 3 (Car3), matrix metalloproteinase 9 (Mmp9), and MutY DNA glycosylase (Mutyh) involved in the "oxidative stress response" of lung tissues in the silicosis model group were lower than those of the control group (all P<0.05). Conclusion Oxidative stress response exists in silicosis patients. The oxidative stress-related genes Car3, Mmp9, and Mutyh are altered in the mouse lung tissues of the silicosis model through the oxidative stress pathway, suggesting that they could be new targets for the treatment of silicosis.

Objective:To investigate the mechanism of Sulfo-N-succinimidyloleate (SSO) regulating lipid metabolism disorder induced by silicon dioxide (SiO 2) . Methods:In March 2023, Rat alveolar macrophages NR8383 were cultured in vitro and randomly divided into control group (C), SSO exposure group (SSO), SiO 2 exposure group (SiO 2) and SiO 2+SSO exposure group (SiO 2+SSO). NR8383 cells were exposure separately or jointly by SSO and SiO 2 for 36 h to construct cell models. Immunofluorescence and BODIPY 493/ 503 staining were used to detect cluster of differentiation (CD36) and intracellular lipid levels, the protein expression levels of CD36, liver X receptors (LXR), P-mammalian target of rapamycin (P-mTOR) and cholinephosphotransferase 1 (CHPT1) were detected by Western blot, respectively, and lipid metabolomics was used to screen for different lipid metabolites and enrichment pathways. Single-factor ANOVA was used for multi-group comparison, and LSD test was used for pair-to-group comparison. Results:SiO 2 caused the expression of CD36 and P-mTOR to increase ( P=0.012, 0.020), the expression of LXR to decrease ( P=0.005), and the intracellular lipid level to increase. After SSO treatment, CD36 expression decreased ( P=0.023) and LXR expression increased ( P=0.000) in SiO 2+SSO exposure group compared with SiO 2 exposure group. Metabolomics identified 87 different metabolites in the C group and SiO 2 exposure group, 19 different metabolites in the SiO 2 exposure group and SiO 2+SSO group, and 5 overlaps of different metabolites in the two comparison groups, they are PS (22∶1/14∶0), DG (O-16∶0/18∶0/0∶0), PGP (i-13∶0/i-20∶0), PC (18∶3/16∶0), and Sphinganine. In addition, the differential metabolites of the two comparison groups were mainly concentrated in the glycerophospholipid metabolism and sphingolipid metabolism pathways. The differential gene CHPT1 in glycerophospholipid metabolic pathway was verified, and the expression of CHPT1 decreased after SiO 2 exposure. Conclusion:SSO may improve SiO 2-induced lipid metabolism disorders by regulating PS (22∶1/14∶0), DG (O-16∶0/18∶0/0∶0), PGP (i-13∶0/i-20∶0), PC (18∶3/16∶0), SPA, glycerophospholipid metabolism and sphingolipid metabolism pathways.

Objective To screen mitochondria-targeting differential genes in alveolar macrophages of silicosis pa-tients and explore the role of mitochondrial homeostasis in alveolar macrophages of silicosis patients.Methods High-throughput sequencing dataset GSE174725 was downloaded,and differentially expressed genes were screened with R software and P＜0.05,|LogFC|＞1,and then intermixed with mitochondrial gene bank MitoCarta3.0 to obtain mitochondria-targeted differentially expressed genes.Then enrichment analysis was carried out to obtain the biological processes and pathways involved in differential genes,and the protein-protein interaction network was constructed.In addition,alveolar macrophages from silicosis patients and healthy controls were collected,the ex-pression levels of differential genes were detected by RT-qPCR,and the expressions of mitochondria-related factors mitochondrial fusion protein 1(MFN1),optic atrophy 1(OPA1)and dynamin-related protein 1(DRP1)in alveolar macrophages of silicosis patients were investigated by Western blot.Results A total of 204 differentially expressed genes were screened in silicosis patients,among which 62 differentially expressed genes were up-regulated,142 dif-ferentially expressed genes were down-regulated,and 22 differentially expressed genes were mitochondria-targeted.The concentration analysis of differentially expressed genes targeted by mitochondria showed that the cell compo-nents mainly enriched included mitochondrial membrane,endoplasmic membrane side components,etc.The bio-logical processes mainly enriched included mitochondrial electron transfer from NADH to ubiquinone,inflammatory response,immune response,etc.The main molecular functions enriched included the rotation mechanism of proton transport ATP synthase activity,NADH dehydrogenase activity,chemokine activity,etc.KEGG enrichment analy-sis mainly focused on the involvement in chemical carcinogenesis-ROS,IL-17 signaling pathway,toll-like receptor signaling pathway,chemokine signaling pathway,TNF signaling pathway,etc.In addition,RT-qPCR results showed that the expressions of mitochondrial cytochrome coxidase 1,mitochondrial cytochrome coxidase 2,mito-chondrial cytochrome coxidase 3,mitochondrially encoded NADH dehydrogenase 1,mitochondrially encoded NADH dehydrogenase 3,mitochondrially encoded NADH dehydrogenase 5,superoxide dismutase and mitochondri-ally encoded ATP synthase 6 gene were down-regulated in silicosis patients(P＜0.05).Western blot and RT-qPCR results showed that,in silicosis patients,the expression of MFN1 and OPA1 decreased(P＜0.05),while the expression of DRP1 increased(P＜0.05).Conclusion Bioinformatics analysis and validation,eight mito-chondrial targeted differential genes(MT-CO1,MT-C02,MT-CO3,MT-ND1,MT-ND3,MT-ND5,SOD and MT-ATP6)were finally obtained,which were enriched in mitochondrial respiratory chain and oxidative stress pathways and might play an important role in the process of silicosis.

ObjectiveTo explore the distribution of pharyngeal microbiota in coal miners exposed to dust. Methods Eight coal miners who had been engaged in occupational dust exposure for more than 20 years were selected as the dust-exposed group, and four coal miners who were not exposed to dust at work were selected as the control group using the judgment sampling method. Pharyngeal secretions of the coal miners were collected with throat swabs, and its pharyngeal microbiota was analyzed. The diversity, abundance and evenness of the microbiota were analyzed by gene sequencing using the 16sRNA gene high-throughput sequencing technology. Results A total of 254 operational taxonomic units of pharyngeal microbiota were detected in the coal miners in the control group, which was 210 more than that in the dust-exposed group. The Chao1 index, Shannon index, PD-tree index and Pielou index of pharyngeal microbiota in the dust-exposed group decreased compared with the control group (all P<0.01). The abundance of Bacteroidetes and Clostridum, at the phylum level, in the pharynx of coal miners in the dust-exposed group was higher than that in the control group (all P<0.05). The abundance of Prevotella, Neisseria, and Monas, at the genus level, in the pharynx of coal miners in the dust-exposed group was higher than that in the control group(all P<0.05), while the abundance of Lactobacillus decreased (P<0.05). The analysis results of the receiver operating characteristic curve showed that Lactobacillus, Fusobacterium and Rothia may play a role for pharyngeal microbiota imbalance prediction in dust-exposed workers, and the area under the curves were all 1.00±0.00. Conclusion The species diversity and evenness of pharyngeal microbiota in coal miners exposed to dust are decreased, which may be related to the continuous inhalation of coal dust that disrupts the microbial environment of the throat.

Objective:To investigate the mechanism of Sulfo-N-succinimidyloleate (SSO) regulating lipid metabolism disorder induced by silicon dioxide (SiO 2) . Methods:In March 2023, Rat alveolar macrophages NR8383 were cultured in vitro and randomly divided into control group (C), SSO exposure group (SSO), SiO 2 exposure group (SiO 2) and SiO 2+SSO exposure group (SiO 2+SSO). NR8383 cells were exposure separately or jointly by SSO and SiO 2 for 36 h to construct cell models. Immunofluorescence and BODIPY 493/ 503 staining were used to detect cluster of differentiation (CD36) and intracellular lipid levels, the protein expression levels of CD36, liver X receptors (LXR), P-mammalian target of rapamycin (P-mTOR) and cholinephosphotransferase 1 (CHPT1) were detected by Western blot, respectively, and lipid metabolomics was used to screen for different lipid metabolites and enrichment pathways. Single-factor ANOVA was used for multi-group comparison, and LSD test was used for pair-to-group comparison. Results:SiO 2 caused the expression of CD36 and P-mTOR to increase ( P=0.012, 0.020), the expression of LXR to decrease ( P=0.005), and the intracellular lipid level to increase. After SSO treatment, CD36 expression decreased ( P=0.023) and LXR expression increased ( P=0.000) in SiO 2+SSO exposure group compared with SiO 2 exposure group. Metabolomics identified 87 different metabolites in the C group and SiO 2 exposure group, 19 different metabolites in the SiO 2 exposure group and SiO 2+SSO group, and 5 overlaps of different metabolites in the two comparison groups, they are PS (22∶1/14∶0), DG (O-16∶0/18∶0/0∶0), PGP (i-13∶0/i-20∶0), PC (18∶3/16∶0), and Sphinganine. In addition, the differential metabolites of the two comparison groups were mainly concentrated in the glycerophospholipid metabolism and sphingolipid metabolism pathways. The differential gene CHPT1 in glycerophospholipid metabolic pathway was verified, and the expression of CHPT1 decreased after SiO 2 exposure. Conclusion:SSO may improve SiO 2-induced lipid metabolism disorders by regulating PS (22∶1/14∶0), DG (O-16∶0/18∶0/0∶0), PGP (i-13∶0/i-20∶0), PC (18∶3/16∶0), SPA, glycerophospholipid metabolism and sphingolipid metabolism pathways.

Background Silicosis is an occupational disease mainly characterized by pulmonary progressive fibrosis induced by the accumulation of free silica (SiO₂) in the lungs due to long-term exposure to SiO₂ dust. It has been shown that neutrophil extracellular traps (NETs) are increased in the lung tissues of silicotic mice after 28 d SiO₂ exposure, but it is unclear how the levels of NETs change throughout entire progression of silicosis in mice. Objective To observe the levels of NETs and pathological changes in the lungs of silicotic mice after different duration of SiO₂ exposure, and to confirm the possible role and significance of NETsin the development of SiO₂-induced pulmonary fibrosis. Methods A total of 28 SPF male C57BL/6J mice were randomly divided into a control group, and a model group, and the model group was subdivided into, a 2 d model group, a 7 d model group, and a 28 d model group, with 7 mice in each group. The mice in the model groups were given intratracheal instillation with 10 mg SiO₂ suspension (50 μL), and the mice in the control group were received same volume of saline. Mice were sacrificed and samples were collected at designed time points. The pathological changes of lung tissues of mice were observed after hematoxylin-eosin (HE) and Van Gieson (VG) staining. Immunofluorescence was used to observe the NETs markers citrullination histone H3 (CitH3) and myeloperoxidase (MPO) in bronchoalveolar lavage fluid (BALF), and the percentage of NETs-positive cells was calculated. PicoGreen fluorescent dye kit was used to detect the content of extracelluar DNA (ex-DNA) in mouse BALF, and the expression levels of fibrosis-related proteins α-smooth muscle actin (α-SMA) and fibronectin (FN) and NETs marker CitH3 in lung tissues of mice were detected by Western blot (WB). Results Compared with the control group, inflammatory cells accumulation, alveolar wall thickening, and collagen deposition were obviously observed in the lungs of the silicosis model groups, and a large number of silicone nodules were recorded in the lung tissues in the 28 d group. Compared with the control group, the expressions of α-SMA and FN in the lung tissue of the 28 d group were significantly increased (P<0.05). The percentages of NETs in BALF increased significantly in the 2 d and the 7 d model group, then decreased in the 28 d model group (P<0.05). Compared with the control group (7.434±0.258) ng·mL⁻¹, the ex-DNA levels in BALF of mice in the 2 d [(35.110±6.331) ng·mL⁻¹], the 7 d [(39.491±6.948) ng·mL⁻¹], and the 28 d [(23.360±4.809) ng·mL⁻¹] model groups were increased (P<0.05), and the increase of ex-DNA in the 2 d and the 7 d model groups were statistically significant (P<0.05). In comparison with the control group, the protein level of CitH3 was significantly increased in the lung tissues of mice in the 7 d model group (P<0.05). Conclusion The content of NETs increases significantly and reaches a peak in the early inflammatory stage of silicosis, and decreases as the disease progresses to the fibrotic stage, suggesting that NETs may play a role in early stage of silicosis.

Objective:To screen the differential metabolites and metabolic pathways in silicosis model by analyzing plasma metabolomics of silicosis rats.Methods:In May 2021, twenty male SD rats were randomly divided into control group (C), 1-week silicosis group (S1W), 2-week silicosis group (S2W) and 4-week silicosis group (S4W), with 5 rats in each group. Rats were intratracheally instillated with 1ml crystalline SiO 2 suspension (50 mg/ml) or normal saline and were sacrificed after 1 week, 2 weeks and 4 weeks, HE staining was used to observe the lung pathology of rats. The plasma samples were analyzed by UPLC-IMS-QTOF mass spectrometer to screen out potential differential metabolites in silicosis models and analyze their lipid enrichment. Results:HE results showed that nodules formed in the silicosis model group, and with the extension of time, nodules gradually increased and alveolar structure was gradually destroyed. Metabolomics screened out 14 differential metabolites in S1W, 24 in S2W, and 28 in S4W, and found that the differential metabolites were mainly enriched in the metabolism of glycerophospholipid metabolism, fatty acid degradation, Glycosylphosphatidylinositol (GPI) -anchor biosynthesis, fatty acid elongation and other metabolic pathways.Conclusion:There are significant changes in plasma lipid metabolites in silicosis rat models.

Background Pneumoconiosis is the most serious occupational disease in China, and silicosis accounts for about half of it. Any intervention effect of physical exercise as the key and core of lung rehabilitation training on silicosis is still unclear. Objective To explore potential intervention effect of physical exercise on silicotic mice. Methods Forty SPF C57BL/6 male mice were randomly divided into four groups, 10 in each group, including a control group, a physical exercise group, a silicosis model group, and a silicosis model + physical exercise intervention group. Silicotic mouse model was established by using 50 μL SiO₂ suspension (200 mg·mL⁻¹). A treadmill was used to prepare mice receiving physical exercise at 0° inclination, 12.3 m·min⁻¹, 60 min·d⁻¹, 5 d·week⁻¹ for 4 weeks. Pathological morphology of lung tissues was evaluated after hematoxylin-eosin (HE) staining; deposition of collagen in lung tissues was evaluated after Van Gieson (VG) staining; expression of p-protein kinase R-like endoplasmic reticulum kinase (PERK) was detected by immunofluorescence staining; expressions of cyclin dependent kinase inhibitors (p21) and p-p38 mitogen activated protein kinase (p38) were detected by immunohistochemistry. The protein expressions of endoplasmic reticulum stress signal factors [p-inositol-requiring enzyme-1α (p-IRE-1α), p-PERK, and p-eukaryotic initiation factor-2α (p-eIF-2α)], senescence signal factors (p-p53, p21, and p16), mitogen-activated protein kinase (MAPK) signal factors [p-p38, p-extracellular regulated protein kinases (p-ERK), and p-stress-activated protein kinase (p-JNK)] were detected by Western blotting. Results After designed acute SiO₂ exposure, the images of micro computed tomography (CT) showed high density shadows in lung tissues of the silicotic mice and less shadows in lung tissues of the physical exercise intervention mice. After HE staining, the proportions of silicotic nodule area in lung tissues was (18.67±3.89) % in the silicosis model group, and significantly decreased to (8.78±1.05) % in the silicosis model + physical exercise intervention group (P<0.05). After VG staining, the proportion of collagen fiber area of lung tissues was (10.37±2.18) % in the silicosis model group, and significantly decreased to (4.35±0.89) % in the silicosis model + physical exercise intervention group (P<0.05). The results of immunofluorescence staining showed that in the silicosis model group, the expression of p-PERK increased at the location of silicotic nodules, while in the silicotic model + physical exercise intervention group, the expression of p-PERK decreased. The immunohistochemical staining results showed that the expression of p21 and p-p38 increased in the lung tissues of the silicosis model group; the expression of p21 and p-p38 decreased in the lung tissues of the silicosis model + physical exercise intervention group. The results of Western blotting showed that compared with the control group, the expression levels of p-IRE-1α (0.11±0.03), p-PERK (0.95±0.40), p-eIF-2α (3.53±0.91), p-p53 (1.78±0.07), p21 (1.98±0.10), p16 (1.26±0.17), p-p38 (0.41±0.09), p-ERK (0.42±0.05), and p-JNK (3.20±1.23) of the silicosis model group were all upregulated (P<0.05). Compared with the silicosis model group, the expression levels of p-IRE-1α (0.03±0.01), p-PERK (0.31±0.12), p-eIF-2α (0.30±0.06), p-p53 (0.76±0.08), p21 (0.18±0.11), p16 (0.70±0.24), p-p38 (0.03±0.00), p-ERK (0.19±0.03), and p-JNK (0.46±0.21) of the silicosis model + physical exercise intervention group were downregulated (P<0.05). Conclusion Physical exercise may alleviate pulmonary fibrosis in silicotic mice, and inhibit abnormal expressions of endoplasmic reticulum stress signal, MAPK signal, and senescent signal.