Role of Endoplasmic Reticulum Stress in Silica-induced Apoptosis in RAW264.7 Cells / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>We investigated the role of endoplasmic reticulum stress (ERS) in silica-induced apoptosis in alveolar macrophages in vitro.</p><p><b>METHODS</b>RAW264.7 cells were incubated with 200 μg/mL silica for different time periods. Cell viability was assayed by the MTT assay. Cell apoptosis was evaluated by DAPI staining, flow cytometry analysis, and Western blot analysis of caspase-3. Morphological changes in the endoplasmic reticulum were observed by transmission electron microscopy. The expression of ERS markers binding protein (BiP) and CCAAT-enhancer-binding protein homologous protein (CHOP) was examined by Western blotting and real-time PCR. As an inhibitor of ERS, 4-phenylbutyric acid (4-PBA) was used in the experiments.</p><p><b>RESULTS</b>Silica exposure induced nuclear condensation and caspase-3 expression in RAW264.7 cells. The number of apoptotic cells increased after silica exposure in a time-dependent manner. Silica treatment induced expansion of the endoplasmic reticulum. In addition, the expression of BiP and CHOP increased in silica-stimulated cells. Furthermore, 4-PBA treatment inhibited silica-induced endoplasmic reticulum expansion and the expression of BiP and CHOP. Moreover, 4-PBA treatment attenuated nuclear condensation, reduced apoptotic cells, and downregulated caspase-3 expression in silica-stimulated cells.</p><p><b>CONCLUSION</b>Silica-induced ERS is involved in the apoptosis of alveolar macrophages.</p>

Transcriptional Factor Snail Mediates Epithelial-Mesenchymal Transition in Human Bronchial Epithelial Cells Induced by Silica / 生物医学与环境科学（英文）

Epithelial-mesenchymal transition (EMT) plays an important role in fibrotic diseases. We have previously showed that silica induces EMT in human bronchial epithelial cells (BECs); however, the underlying mechanism of silica-induced EMT is poorly understood. In the present study, we investigated the role of Snail in silica-induced EMT in human BECs in vitro. Human BECs were treated with silica at various concentrations and incubation times. Then MTT assay, western blot, electrophoretic mobility shift assay (EMSA), and small interfering RNA (siRNA) transfection were performed. We found that silica increased the expression and DNA binding activity of Snail in human BECs. SNAI siRNA inhibited the silica-induced expression of Snail. Moreover, SNAI siRNA upregulated the expression of epithelial marker E-cadherin, but attenuated the expression of mesenchymal marker α-smooth muscle actin and vimentin in silica-stimulated cells. These results suggest that Snail mediates the silica-induced EMT in human BECs.

Roles of Rho/Rock signaling pathway in silica-induced epithelial-mesenchymal transition in human bronchial epithelial cells / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the roles of Rho/Rock signaling pathway in silica-induced Epithelial-mesenchymal transition (EMT) in human bronchial epithelial cells (BEC) in vitro.</p><p><b>METHODS</b>Human BEC were incubated with silica with various concentrations for indicated times. Cell viability was assayed by MTT test. Morphologic Changes were observed by microscope. Mesenchymal marker α-smooth muscle actin (α-SMA), vimentin (Vim), and epithelial marker E-cadherin (E-cad) were analyzed by Western Blot. The pull-down assay was used to measure Rho activity. In the prevention experiments, the specific inhibitor for Rho effector ROCK (Y27632) was used to inhibit the activity of Rho.</p><p><b>RESULTS</b>Human BEC stimulated with silica were converted from a "cobblestone" epithelial structure into an elongated fibroblast-like shape structure. Incubation of human BEC with silica induced de novo expression of α-SMA and Vim, and loss of E-cad. Also, silica treatment resulted in Rho activation in human BEC. Y27632 up-regulated the E-cad expression but attenuated α-SMA and Vim expression in silica-stimulated cells.</p><p><b>CONCLUSION</b>The activation of Rho/ROCK signaling pathways is most likely involved in Silica-induced EMT in human bronchial epithelial cells.</p>

Study on the relationship between Chinese medicine constitutive susceptibility and diversity of syndrome in diabetic nephropathy / 中国结合医学杂志

<p><b>OBJECTIVE</b>To explore the relationship between Chinese medicine (CM) constitutive susceptibility and syndrome diversity in diabetic nephropathy (DN).</p><p><b>METHODS</b>Epidemiologic investigation on constitution adopting the "Constitution in Chinese Medicine Questionnaire" (CCMQ), and survey on syndrome type by CM syndrome scale (preliminary) were carried out in 180 DN patients. Cluster analysis on symptom items was used to determine the syndrome type, and canonical correlation analysis was used to analyze the relationship between patients' constitution and syndrome.</p><p><b>RESULTS</b>Baseline levels in all enrolled patients were not different statistically. Cluster analysis showed 8 syndromes existed in DN patients, namely: I, qi-yin deficiency with qi-stagnancy type; II, yin-yang deficiency with heat-water-blood stasis type; III, qi-yin deficiency with dampness-heat type; IV, yin-yang deficiency with blood-stasis and heat type; V, qi-yin deficiency with stagnant heat type; VI, yin-yang deficiency with inner dampness-heat stagnancy type; VII, yin deficiency with heat stagnancy type; and VIII, Kidney (Shen)-Spleen (Pi) deficiency with stagnant heat type. Correlation analysis on the 8 syndromes and the 9 constitutions showed statistical significant correlations between syndrome III and dampness-heat constitution (P=0.0001); syndrome IV and blood-stasis constitution (P=0.0001); and syndrome VII and yin-deficiency constitution (P=0.0180).</p><p><b>CONCLUSION</b>Certain relationship revealed between CM constitutions and syndrome types; constitution decides the disease genesis, its syndrome type and prognosis, as well as the change of syndromes.</p>

The influence of SiO2 on epithelial-mesenchymal transition (EMT) in human bronchial epithelial cells / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate SiO2-induced EMT in human bronchial epithelial cells HBE in vitro.</p><p><b>METHODS</b>HBE cells were cultured and then stimulated with indicated doses of SiO2 (0, 50, 100, 200, 300 µg/ml). The morphological changes were observed by microscope. In addition, Western blot was per-formed to detect the expression of E-cad, α-SMA and Vim. The changes of migration ability were examined by wound-healing assay in vitro.</p><p><b>RESULTS</b>(1) After exposure to SiO2, HBE cells lost contact with their neighbor and displayed a spindle-shape, fibroblast-like morphology. (2) Compared with the control, the E-cad (300 µg/ml group) expression downregulated 2.98 fold (P < 0.05), and the Vim (300 µg/ml group) and α-SMA (200 µg/ml group) expression upregulated 4.46 fold and 3.55 fold (P < 0.05). There were significant differences between 100, 200, 300 µg/ml groups and the control group (P < 0.05). (3) In the test group, the percentage of wound-healing areas/wound areas were larger than those in control group (P < 0.05).</p><p><b>CONCLUSIONS</b>SiO2 could induce EMT in human bronchial epithelial cells.</p>

Association of Chinese medicine constitution susceptibility to diabetic nephropathy and transforming growth factor-β1 (T869C) gene polymorphism / 中国结合医学杂志

<p><b>OBJECTIVE</b>To explore the association of Chinese medicine constitution susceptibility to diabetic nephropathy (DN) and transforming growth factor (TGF)-β1 (T869C) gene polymorphism.</p><p><b>METHODS</b>TGF-β1 gene polymorphism detected with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was screened for 180 DN cases and 180 type 2 diabetic mellitus (T2DM) cases without combined DN. Patients with DN were surveyed epidemiologically with constitution in the Chinese medicine questionnaire (CCMQ). Binary logistic regression analysis was utilized to study the correlation between nine types of Chinese medicine constitution and TGF-β1 (T869C) gene polymorphisms.</p><p><b>RESULTS</b>The DN group has a higher frequency of TGF-β1 (T869C) gene polymorphism than the T2DM group, and CC/CT genotypes than the T2DM group [CC, CT, TT (DN group): 88, 87, 5 (cases) versus (T2DM group) 71, 73, 36 (cases), P<0.05]. The phlegm-dampness constitution, damp-heat constitution, and blood stasis constitution have correlations with TGF-β1 (T869C) gene polymorphism.</p><p><b>CONCLUSION</b>Chinese medicine constitutions were associated with TGF-β1 (T869C) gene polymorphism, a potential predictor of susceptibility to DN in T2DM patients.</p>

Effect of Twist gene on the migration and invasion of gastric carcinoma cells / 中南大学学报(医学版)

OBJECTIVE@#To explore the effect of Twist gene on the migration and invasion of human gastric carcinoma cells.@*METHODS@#MKN28 cells, a human gastric carcinoma cell line, were transfected with PcDNA3.1-Twist plasmid by lipofectamine transfecting technique. The transfected cells were selected with geneticin. Expressions of Twist,ecadherin and vimentin protein were detected by Western blot in cells transfected Twist gene. Matrigel invision chambers were performed to analyse the cell migration and invasion.@*RESULTS@#MKN28 cells transfected with PcDNA3.1-Twist plasmid showed stronger intracellular expression of Twist protein than MKN28 cells transfected with PcDNA3.1 and MKN28 cells without transfection. The expression of ecadherin protein in MKN28 cells transfected with PcDNA3.1-Twist plasmid was significantly decreased compared with that in MKN28 cells transfected with PcDNA3.1 and MKN28 cells without the transfection. However, The expression of vimentin protein in MKN28 cells transfected with PcDNA3.1-Twist plasmid was significantly increased compared with that in MKN28 cells transfected with PcDNA3.1 and MKN28 cells without transfection. The migration and invasion ability of Twist+ - MKN28 cells were stronger than that of MKN28 cells transfected with PcDNA3.1 and MKN28 cells without transfection.@*CONCLUSION@#Twist gene may promote the migration and invasion ability of gastric carcinoma cells through epithelial mesenchymal transition.

Silicon dioxide-upregulated plasminogen activators inhibitor-1 protein expression is dependent on activation of extracellular signal-regulated kinase/activator protein-1 signaling pathway / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the role of extracellular signal-regulated kinase (ERK)/activator protein-1 (AP-1) signaling pathway in SiO(2)-induced plasminogen activators inhibitor-1 (PAI-1) protein expression in human lung epithelial cells A549.</p><p><b>METHODS</b>A549 cells were cultured and then stimulated with 200 microg/ml SiO(2) for 0 approximately 24 h. To prevent AP-1 activity, Curcumin was added into culture medium before incubating with SiO(2) and transient TAM-67 transfection was performed. In addition, PD98059 was pretreated with cells to prevent ERK activity. The PAI-1 protein expression and ERK activity were evaluated by Western blot. The AP-1 DNA binding activity was tested by EMSA.</p><p><b>RESULTS</b>(1) At 4, 8 and 16 h after exposure to SiO(2), the fold change of AP-1 DNA binding activity (relative to the control group) were 1.3, 1.3, and 2.1, respectively (P < 0.05). 10, 25, 50 micromol/L Curcumin inhibited SiO(2)-induced PAI-1 protein expression (inhibition ratio: 20%, 63%, 65%; P < 0.05). TAM-67 downregulated SiO(2)-induced PAI-1 protein expression (inhibition ratio: 59%, P < 0.05). (2) SiO(2) activated ERK and PD98059 downregulated SiO(2)-induced PAI-1 protein expression (inhibition ratio: 51%, P < 0.05). (3) PD98059 downregulated SiO(2)-induced AP-1 DNA binding activity (inhibition ratio: 73%, P < 0.05).</p><p><b>CONCLUSION</b>ERK/AP-1 signaling pathway is responsible for SiO(2)-induced PAI-1 protein expression.</p>

Role of activator protein-1 in pathogenesis of silicosis: an in-vitro study / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the role of activator protein-1 (AP-1) in the up-regulation expression of tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1(TGF-beta(1)) in silica-stimulated macrophage cells (RAW264.7).</p><p><b>METHODS</b>RAW264.7 cells were treated with AP-1 inhibitor Curcumin. The expression of c-jun and c-fos in nuclear protein was detected by western blotting. The level of TNF-alpha and TGF-beta(1) protein in the cell supernatant was measured using enzyme-linked immunoadsorbent assay (ELISA). Meanwhile the expression of TNF-alpha and TGF-beta(1) mRNA was also monitored by reverse transcriptase-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>The nucleoprotein expression of c-jun and c-fos in 10 and 20 micromol/L Curcumin prevention group (1.150 +/- 0.020, 1.010 +/- 0.108, 80.430 +/- 0.023, 0.256 +/- 0.015) were lower than those in silica-stimulated group (1.550 +/- 0.029, 0.860 +/- 0.036) (P < 0.01). In 20 micromol/L Curcumin prevention group and silica stimulated group, the expression of TNF-alpha protein were 23.58 +/- 45.78 and 32.12 +/- 5.34, and the expression of TGF-beta(1) protein were 1582.18 +/- 437.52 and 55.60 +/- 5.51 (P < 0.05 =; the expression of TNF-alpha, TGF-beta(1) mRNA were 0.74 +/- 0.01, 0.22 +/- 0.04 and 2.27 +/- 0.33, 2.96 +/- 0.15 (P < 0.05 =.</p><p><b>CONCLUSION</b>The expression of TNF-alpha, TGF-beta(1) mRNA and proteins is associated with activation of AP-1 in silica-stimulated macrophage cells.</p>

AP-1 regulates TGF-beta1-induced secretion of Type I collagen in human lung fibroblasts / 中南大学学报(医学版)

OBJECTIVE@#To investigate the role of AP-1 in the secretion of Type I collagen in TGF-beta1-stimulated human lung fibroblasts.@*METHODS@#Human lung fibroblasts cell line (HLF-02) was cultured, and then stimulated with 10 microg/L TGF-beta1 at different time points. Curcumin was added into the culture medium to inhibit the AP-1 activity before incubating with TGF-beta1. AP-1 DNA binding activity was assayed by electrophoretic mobility shift assay (EMSA), and the expression of Type I collagen was detected by Western blot and RT-PCR.@*RESULTS@#TGF-beta1 could induce the transcription and secretion of Type I collagen in HLF-02 cells(P<0.05). TGF-beta1 could upregulate the AP-1 DNA binding activity ( P<0.05). Curcumin ( 5, 10, 15, and 20 micromol/L) could inhibit the AP-1 DNA binding activity in TGF-beta1-stimulated cells (the inhibition ratio was 17.1%, 17.6%, 24.2%, and 31.3%; P<0.05). Curcumin (5, 10, 15, and 20 micromol/L) could also inhibit the secretion of Type I collagen significantly (the inhibition ratio was 62.1%, 58.8%, 62.1%, and 59.6%; P<0.05).@*CONCLUSION@#AP-1 is responsible for the secretion of TGF-beta1-induced Type I collagen in human lung fibroblasts.

p38/ERK signal pathways regulating the expression of type I collagen and activity of MMP-2 in TGF-beta1-stimulated HLF-02 cells / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the role of TGF-beta(1)/MAPK signaling pathways in the expression of type I collagen and activity of MMP-2, 9 in human lung fibroblasts.</p><p><b>METHODS</b>Human lung fibroblasts cell line (HLF-02) was cultured and and then stimulated with 10 ng/ml TGF-beta(1) for different time; SB203580 or PD98059 was added into culture medium to block p38 or ERK kinase pathway before incubated with TGF-beta(1); the expression of type I collagen was detected by Western blotting and RT-PCR; zymogram analysis was used to analyze the activity of MMP-2 and MMP-9.</p><p><b>RESULTS</b>(1) In the process of stimulation by TGF-beta(1), the type I collagen mRNA level of 24 h, 48 h and 72 h group was: 1.33 +/- 0.07, 2.46 +/- 0.09 and 2.39 +/- 0.08 respectively; and the type I collagen protein level of 24 h, 48 h and 72 h group was: 114.89 +/- 8.95, 208.16 +/- 6.75 and 211.46 +/- 8.05 respectively; and the activity of MMP-2 of 24 h, 48 h and 72 h group was: 190.33 +/- 5.86, 214.33 +/- 8.39 and 212.67 +/- 11.59 respectively. (2) SB203580 significantly inhibited the TGF-beta(1)-induced expression of type I collagen mRNA, protein and MMP-2 activity (inhibition ratio: 51%, 24% and 20%); (3) PD98059 also significantly attenuated the TGF-beta(1)-induced expression of type I collagen mRNA, protein and MMP-2 activity (inhibition ratio: 42%, 13% and 16%).</p><p><b>CONCLUSION</b>TGF-beta(1) is capable of inducing the expression of type I collagen mRNA and protein and up-regulating MMP-2 activity in HLF-02 cells. p38 and ERK kinase signaling pathways play important role in regulation and control for this process.</p>

Expression and role of nuclear transcription factor Sp1 in macrophages stimulated by silicon dioxide / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the expression and localization of nuclear transcription factor Sp1 in macrophages after stimulated by silicon dioxide in vivo and in vitro.</p><p><b>METHODS</b>Forty Sprague Dawley rats were randomly divided into the control group and the silica exposure group, 20 in each group. The rat silicosis models were established by direct tracheal instillation of silica into rat lung (0.2 g/kg) only once while the control group was instilled with equal amount of saline. Animals were killed at 1st, 7th, 14th, 21st and 28th day after instillation. Dynamic changes of Sp1 protein expression and its cellular localization were detected by immunohistochemistry in pulmonary macrophages. In vitro, Sp1 mRNA and protein expression and their dynamic changes were monitored by RT-PCR and western blotting after stimulated by silicon dioxide in cultured RAW264.7 macrophages respectively. Cellular localization of Sp1 protein was characterized by immunocytochemistry.</p><p><b>RESULTS</b>Compared to the control group, the Sp1 protein expression was increased in pulmonary macrophages and reached the peak at the 14th day in the silica exposure group. In vitro, the Sp1 mRNA level began to rise at 30 minutes after the administration of silicon dioxide and reached the peak at 240 minutes and then decreased to the minimal level at 960 minutes. The Sp1 total protein and nuclear protein also exhibited the similar trend. The former reached the peak at 240 minutes and the latter at 480 minutes. The significant nuclear translocation of Sp1 protein was observed at 120 minutes after the administration of silicon dioxide and became most significant at 480 minutes.</p><p><b>CONCLUSION</b>Silicon dioxide can activate nuclear transcription factor Sp1 in macrophages in vivo and in vitro. Sp1 might play an important pathogenic role in the development of silicosis.</p>

Effects of silicon dioxide on expression of alpha-smooth muscle actin in human lung fibroblasts / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of SiO(2) on the expression of alpha-smooth muscle actin (alpha-SMA) in human lung fibroblasts in vitro and vivo.</p><p><b>METHODS</b>The experimental group comprised 32 rats while 32 rats were included in the control. In vivo, the expression of alpha-SMA in lung tissues of rats exposed to SiO(2), the supernate of RAW264.7 cells, SiO(2) and the growth factor beta(1) (TGF-beta(1)) were investigated, respectively.</p><p><b>RESULTS</b>(1) alpha-SMA positive myofibroblasts appeared in the lung tissues of the 28th day groups exposed to SiO(2). (2) The expression of alpha-SMA in HLF-02 cells was unregulated by TGF-beta(1) and supernate of RAW264.7 cells exposed to SiO(2). (3) The expression of alpha-SMA in HLF-02 cells was not induced by SiO(2).</p><p><b>CONCLUSION</b>Myofibroblasts related to silicosis, and the appearance of myofibroblasts (in vitro) are independent on direct stimulation by SiO(2), but related to the mediator (TGF-beta(1)) secreted by SiO(2) stimulated macrophages.</p>

Transforming growth factor-beta1 induced phenotypic differentiation of human lung fibroblasts through mitogen activated protein kinase-dependent pathway / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the role of MAPK signal transduction in TGF-beta1 induced phenotypic differentiation of human lung fibroblasts.</p><p><b>METHOD</b>Human lung fibroblasts cell line (HLF-02) were cultured and then stimulated with 10 ng/ml TGF-beta1 for different time; SB203580 or PD98059 was added into culture medium to prevent p38 or Erk kinase pathway before incubating with TGF-beta1; the expression of alpha-smooth muscle actin (alpha-SMA) was detected by Western blotting and RT-PCR; Western blotting was used to assay phosphorylation of p38, Erk, and JNK kinase.</p><p><b>RESULTS</b>(1) In the process of stimulation by TGF-beta1, the alpha-SMA mRNA expression levels of 24, 48 and 72 h groups were 1.87 +/- 0.11, 2.49 +/- 0.10, 3.02 +/- 0.15 respectively; and the alpha-SMA protein expression levels of 24, 48 and 72 h groups were 3.20 +/- 0.14, 3.96 +/- 0.21, 4.57 +/- 0.13 respectively. (2) TGF-beta1 induced p38, Erk kinase phosphorylation but not JNK kinase. (3) The inhibitors SB203580 and PD98059 suppressed TGF-beta1-induced p38 kinase and Erk phosphorylation respectively. (4) SB203580 significantly attenuated TGF-beta1-induced alpha-SMA mRNA and protein expression (inhibition rate: 30% and 40%); PD98059 also significantly inhibited TGF-beta1-induced alpha-SMA mRNA and protein expression (inhibition rate: 10% and 20%).</p><p><b>CONCLUSION</b>TGF-beta1 is capable of inducing the phenotypic differentiation of HLF-02, which is regulated by p38 and Erk kinase signal pathway.</p>

Effects of silica on the expression of plasminogen activator inhibitor-1 and activator protein-1 in human alveolar epithelial cells type II / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of silicosis by observing the effects of silica on the expression of plasminogen activator inhibitor-1 (PAI-1) and activator protein-1 (AP-1) in human alveolar epithelial cells type II (A549).</p><p><b>METHODS</b>A549 cell and SiO(2) (200 microg /ml) were co-cultured for 0, 4, 8, 16 and 24 h respectively. The reverse transcriptase polymerase chain reaction (RT-PCR), Western blotting and SP immunocytochemistry were used for detections of the PAI-1 mRNA and protein expression. The nucleoprotein and total protein expression of AP-1 were investigated by Western blotting.</p><p><b>RESULTS</b>The expression levels of PAI-1 mRNA and protein were increased in a time-dependent manner(r(mRNA) = 0.911, r(protein) = 0.902, P < 0.05). The expressions of PAI-1 mRNA and protein in experimental groups were higher than that in control group (P < 0.05) and was the highest in 24 h group [(0.73 +/- 0.01) vs (0.36 +/- .03)]. The nucleoprotein expressions of c-jun/c-fos in experimental groups were also higher than in control group (P < 0.05), and the nucleoprotein expression level of c-jun was the highest in 4 h group [(1.54 +/- 0.02) vs (0.56 +/- 0.03)]; the nucleoprotein expression level of c-fos was the highest in 8 h group [(0.36 +/- 0.01) vs (0.15 +/- 0.01)]. Both c-jun and c-fos expression were decreased after 16 h, but the total protein expression of c-jun/c-fos had no difference in all experimental groups. The positive signal of PAI-1 was located in cytoplasm and nucleus.</p><p><b>CONCLUSION</b>SiO(2) could induce PAI-1 expression of A549 in a time-dependent manner, and AP-1 activation can be observed in early time.</p>

Sudy on the activation of early growth response factor-1 by silica dioxide and its signal pathway / 中华病理学杂志

<p><b>OBJECTIVE</b>To discuss the role of early growth response factor (Egr)-1 and it's upstream signaling pathway in the development of silicosis.</p><p><b>METHODS</b>The expression and localization of Egr-1 were analyzed by immunofluorescence and in-situ hybridization. The activity of Egr-1 was observed in treated cells by using a reporter plasmid and EMSA, the activity of ERK1/2 in RAW264.7 incubated with SiO(2) by using a kinase assay, and further by using a kinase inhibitor assay to investigate the role of upstream kinase in the signal pathway of the activation of Egr-1.</p><p><b>RESULTS</b>The obvious increase of expression and transcription of Egr-1 was observed shortly after being treated by silica and its activity increased abruptly. There was an increase of the activity of ERK1/2 in RAW264.7 cells treated, which reached a peak at 30 minutes. The expression and transcription of Egr-1 decreased maniferstly after using kinase inhibitors.</p><p><b>CONCLUSION</b>Egr-1 expression can be induced by silica dioxide in RAW264.7 cells, and the ERK1/2, p38 kinases may take part in this process which suggest the pathway of SiO(2), ERK1/2, p38 and Egr-1 may play an important role in the development of silicosis.</p>

Expression and role of early growth response gene-1 in experimental silicosis of rat / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the expression and location of early growth response gene-1 (Egr-1), transforming growth factor-beta(1) (TGF-beta(1)), fibronectin (FN) in silicotic rat and to discuss the role of Egr-1 in the development of silicosis.</p><p><b>METHODS</b>Silicotic animal model of rat was established, and the expressions of Egr-1, TGF-beta(1), FN in various lung cells of silicotic rat were analysed by using immunohistochemical technique (SP) and the image analysis.</p><p><b>RESULTS</b>The expressions of Egr-1 in bronchial epithelial cell, pulmonary macrophage, alveolar epithelium cell and interstitial cell in lung silicotic tissue (gray values: 118.58 +/- 5.65 - 168.52 +/- 5.67) were higher than those of controls (gray values: 166.23 +/- 5.23 - 188.12 +/- 8.35) during 1 - 28 days, and the expression was mainly in nucleus; the expressions of TGF-beta(1) in these cells (gray values: 123.49 +/- 5.65 - 170.24 +/- 3.56) were also higher than those of controls (166.53 +/- 6.25 - 198.56 +/- 4.53), and the expression was mainly in cytoplasm. The expressions of FN in bronchial epithelial cell, pulmonary macrophage and alveolar epithelial cell (gray values: 150.32 +/- 6.54 - 201.54 +/- 7.38) were lower, while those in interstitial cell (gray values: 121.43 +/- 5.65 - 167.55 +/- 6.35) were higher than those of controls. The changes of TGF-beta(1) and Egr-1 expression level in bronchial epithelial cell, pulmonary macrophage, alveolar epithelium cell and interstitial cell were synchronous during the experiment (1 - 28 days). Both of them were correlated with each other (r = 0.61, P < 0.01), while the expression of FN was not correlated with Egr-1, but correlated to TGF-beta(1) in interstitial cell (r = 0.46, P < 0.01).</p><p><b>CONCLUSION</b>Silicon dioxide could up-regulate the expression of nuclear transcription factor Egr-1 in several kinds of cell in lung. The activated Egr-1 may coordinate the expression of TGF-beta(1) and FN to regulate the development of silicosis.</p>

The role of Egr-1 and NF-kappaB in the pathogenesis of silicosis: an in-vitro study / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the correlation between the expression of Egr-1 and NF-kappaB and the up-regulation of TNF-alpha and TGF-beta1 in macrophages after stimulation by silica in-vitro.</p><p><b>METHODS</b>Macrophages were treated with antibodies against Egr-1 and NF-kappaB and antisense oligonucleotides. The level of TNF-alpha protein in the cell supernatant was then measured using enzyme-linked immunoadsorbent assay (ELISA). The expression of TGF-beta1 protein was detected by immunocytochemistry. The expression of TNF-alpha and TGF-beta1 mRNAs was also monitored by reverse transcriptase-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>Compared with silica-stimulated macrophages untreated with antibodies, the cells treated with 10 micro g/ml of Egr-1 or NF-kappaB antibodies were associated with reduced expression of TNF-alpha and TGF-beta1 proteins and mRNAs (P < 0.05). Compared with silica-stimulated untransfected group, the antisense group was associated with obvious reduction in the expression of TNF-alpha and TGF-beta1 proteins and mRNAs (P < 0.05).</p><p><b>CONCLUSION</b>The expression of TNF-alpha and TGF-beta1 mRNAs and proteins are associated with activation of Egr-1 and NF-kappaB in macrophages, after stimulation by silica. It is possible that the corresponding antibodies and antisense oligonucleotides may become a potential therapeutic tool in the management of silicosis in the future.</p>