OBJECTIVEThis study was aimed to investigate the effects of emodin combined with 3'-azido-3'-deoxythymidine (AZT) on proliferation and apoptosis of leukemia cell line KG-1a cells and its mechanism.

METHODSKG-1a cells were transfected with Egr-1 siRNA by electroporation and divided into blank control (KG-1a), nonspecific control (KG-1a/NC) and Egr-1 siRNA (KG-1a/siRNA) groups. Transfection efficiency was tested through fluorescence microscopy and flow cytometry and the transfection effect was detected by using qPCR. The cell proliferation rate was detected with MTT method. After the cells were treated with 10 µmol/L of emodin, 3200 or 1600 µmol/L of AZT and their combinations, the proliferation inhibition rates and the apoptosis rates of cells in 3 groups were detected with MTT method and FCM, respectively.

RESULTSThe transfection efficiency of Egr-1 siRNA was found to reach more than 59.21%; as compared with blank control(KG-1a) and nonspectic control(KG-1a/NC), the cell proliferation in Egr-1 siRNA group significantly reduced (P<0.01). The combination of emodin and AZT had considerable synergistic inhibitory effects on proliferation of normal KG-1a cells and nonspecific control(KG-1a NC) cells, but the synergistic effects disappeared after Egr-1 gene silencing.

CONCLUSIONThe effects of the combination of emodin and AZT on proliferation and apoptosis may be related with Egr-1.

Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Early Growth Response Protein 1 ; Emodin ; Flow Cytometry ; Humans ; Leukemia ; RNA, Small Interfering ; Transfection ; Zidovudine

AIMTo investigate the dynamic changes of Egr-1 expression in the lungs of acute pulmonary embolism of rats by infusion of autoblood thrombs.

METHODSThe model of pulmonary embolism by infusion of autoblood thrombs in the pulmonary artery of rats was established and the mean pulmonary arterial pressure was continuously monitored by computer, and the results were evaluated by lung perfusion scan and pathological changes. Expression of Egr-1 proteinum and mRNA were measured by immunohistochemistry and reverse transcription polymerase chain reaction.

RESULTSThe mPAP of rats was increased significantly after infusion of autoblood thrombs at the half hour, and reached high level at the second hour, then remained the high level to four hours compared with group control at the same time point (P < 0.01). ECT image was showed significantly filling defect after infusion of autoblood thrombs at the first hour. The infused thromb was witnessed by hematoxylin and eosin stain. In the tracheal epithelium cells, alveolar epithelium cells and vascular smooth muscle cells of embolism rats, Egr-1 protein expression was increased significantly after embolization at the second hour compared with group control at the same time point (P<0.01), and was decreased slowly at the fourth hour. Egr-1 mRNA expression was showed the similar changes.

CONCLUSIONExpression of Egr-1 was low level in group control, but increased significantly after infusion of autoblood thromb at the second hour in the specificity of cells, suggesting that Egr-1 expression might be an important link of pathological changes in the acute pulmonary embolism.

Animals ; Early Growth Response Protein 1 ; genetics ; metabolism ; Gene Expression ; Lung ; metabolism ; Male ; Pulmonary Embolism ; genetics ; metabolism ; pathology ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To investigate the expression of EGR1 gene and the localization of EGR1 protein in bovine skeletal muscle-derived satellite cells (MDSCs), as well as to investigate the mechanism that EGR1 protein enters the nucleus. METHODS: Bovine MDSCs were cultured in differentiation medium for 1 day, 3 days and 5 days, respectively, and each group was triplicate. The expression of EGR1 gene and the localization of EGR1 protein were studied at different differentiation period in MDSCs by qRT-PC and Western blot. Moreover, the changes on the expression of endogenous EGR1 gene and EGR1 proteins were explored by CRISPRi, site-directed mutagenesis and laser confocal method. RESULTS: The results from the qRT-PCR and Western blot showed that the expressions of EGR1 gene on transcription level and translation level were significantly higher in differentiated cells than those in undifferentiated cells. The highest expression was found on the third day after the differentiation, and then began to decline. Immunofluorescence assays showed that EGR1 proteins were preferentially expressed in differentiated MDSCs, and increased along with the increase of number of myotubes. Confocal observation revealed that some EGR1 proteins were transferred into the nucleus in the differentiation of cells, however, the EGR1 proteins would not be detected in the differentiated MDSCs nuclei if a site directed mutagenesis (serine) on EGR1 protein occurred. CONCLUSION During the differentiation of bovine skeletal muscle satellite cells, the transcriptional level of EGR1 gene is increased, and some EGR1 proteins are transferred into the nucleus. The serine phosphorylation at position 533 of the C terminal of EGR1 protein is necessary for the nucleus transfer.
Animals ; Cattle ; Cell Differentiation ; Cell Nucleus ; Cells, Cultured ; Early Growth Response Protein 1 ; genetics ; metabolism ; Muscle Fibers, Skeletal ; Satellite Cells, Skeletal Muscle ; metabolism

OBJECTIVE: To construct hypoxia/radiation inducible promotor HRE1.Egr-1, and to observe its promotive effect on the expression of yCDglyTK gene in nasopharyngeal cancer HNE-1 cells and the anti-tumor effect of yCDglyTK and to lay an experimental foundation for further exploration of new gene-radio therapy of nasopharyngeal cancer. METHODS: pcDNA3.1(-)HRE1.Egr-1.yCDglyTK was constructed by gene recombination technique. Stable yCDglyTK-expressing HNE-1 cells were generated by transfecting the recombinant plasmid into the target cells with liposome. The expression of yCDglyTK was detected by Western blot in 4 groups: a normoxia group, a radiation group, a hypoxia group, and a hypoxia and radiation group. The killing effect of 5-FC in different circumstances was determined by MTT. RESULTS: The expression of yCDglyTK/5-FC gene in all the groups was significantly different(P<0.01),especially in the hypoxia and radiation group. The killing effect of 5-FC on HNE1 cells varied under different conditions, especially in the hypoxia and radiation group. CONCLUSION Hypoxia and radiation can induce the activity of fusion promoter HRE1.Egr-1, and obviously promote the anti-tumor effect of yCDglyTK/5-FC system, suggesting that yCDglyTK may be a candidate suicide gene for gene-radio therapy of NPC.
Early Growth Response Protein 1 ; genetics ; Flucytosine ; pharmacology ; Gene Fusion ; physiology ; Genetic Therapy ; methods ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; Nasopharyngeal Neoplasms ; genetics ; radiotherapy ; therapy ; Response Elements ; genetics ; Thymidine Kinase ; genetics ; metabolism ; Tumor Cells, Cultured

OBJECTIVETo 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.

METHODSSilicotic 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.

RESULTSThe 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).

CONCLUSIONSilicon 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.

Animals ; DNA-Binding Proteins ; analysis ; physiology ; Disease Models, Animal ; Early Growth Response Protein 1 ; Fibronectins ; analysis ; physiology ; Immediate-Early Proteins ; analysis ; physiology ; Immunohistochemistry ; Lung ; chemistry ; physiopathology ; Rats ; Silicosis ; etiology ; metabolism ; Transcription Factors ; analysis ; physiology ; Transforming Growth Factor beta ; analysis ; physiology

OBJECTIVETo study influence of lanthanum chloride (LaCl(3)) on the expression of immediate early genes (IEGs) including c-jun, early growth response gene 1 (Egr1) and activity-regulated cytoskeletal gene (Arc) in the hippocampus of rats, and discuss the mechanism of LaCl(3) undermining learning and memory capability.

METHODSForty female Wistar adult rats were divided into control group, low LaCl(3)-contaminated group (0.25%), medium LaCl(3)-contaminated group (0.50%), and high LaCl(3)-contaminated group (1.00%) by randomized design. Each group had ten female rats along with five male rats and mated by the ratio of 2:1. The amounts of pups in the above four groups were 80, 83, 78 and 75 separately. The pups in respective group were La-dyed by lactation, and then the pups in LaCl(3)-contaminated groups drank 0.25%, 0.50% and 1.00% LaCl(3) separately for one month. Learning and memory capability of pups were measured in jumping stairs experiment. Hippocampal lanthanum content was determined by inductively coupled plasma mass spectrometry (ICP-MS). Hippocampal c-jun, Egr1 and Arc mRNA expression was detected by RT-PCR, and corresponding protein expression was measured by Western blotting method.

RESULTSIn the jumping stairs experiment, pups in 0.25%, 0.50% and 1.00% LaCl(3)-contaminated groups respectively made (1.75 ± 0.71), (2.38 ± 0.92) and (3.00 ± 0.76) mistakes; significantly higher than control group (1.25 ± 0.46) (q values were 4.386, 6.793, P < 0.05). However, the incubation period of 0.25%, 0.50% and 1.00% LaCl(3)-contaminated groups were (174.13 ± 33.72), (139.25 ± 45.83) and (75.50 ± 18.56) respectively, which were all significantly lower than that of control group (206.75 ± 20.47) (q values were 2.958, 6.121, 11.902, P < 0.05). Hippocampal c-jun mRNA expression were (0.89 ± 0.08), (0.77 ± 0.12), (0.58 ± 0.14) and (0.29 ± 0.10); while the c-jun protein expression were (0.72 ± 0.13), (0.64 ± 0.11), (0.43 ± 0.11) and (0.31 ± 0.14), and the Egr1 mRNA expression were (0.78 ± 0.09), (0.61 ± 0.13), (0.53 ± 0.10) and (0.22 ± 0.08), Egr1 protein expression were (0.65 ± 0.18), (0.40 ± 0.15), (0.32 ± 0.13) and (0.14 ± 0.09) in 0.25%, 0.50% and 1.00% LaCl(3)-contaminated groups; and all of which presented a dose-effect relationship that the correlation coefficients of these parameters with dose were -0.900 (t = 11.309, P = 0.000), -0.969 (t = 7.058, P = 0.000), -0.898 (t = 11.179, P = 0.000) and -0.962 (t = 6.739, P = 0.000).

CONCLUSIONLaCl(3) undermines the learning and memory capability of rats, which is possibly related to lower expression of c-jun and Egr1 gene and protein induced by lanthanum in hippocampus.

Animals ; Early Growth Response Protein 1 ; metabolism ; Female ; Gene Expression ; Genes, Immediate-Early ; drug effects ; genetics ; Hippocampus ; drug effects ; metabolism ; Lanthanum ; pharmacology ; Learning ; drug effects ; Male ; Memory ; drug effects ; Proto-Oncogene Proteins c-jun ; metabolism ; Rats ; Rats, Wistar

OBJECTIVEIt is known that intrahepatic renin-angiotensin-aldosterone system (RAAS) plays a key role in liver fibrogenesis. Aldosterone (Aldo), the principal effector molecule of the RAAS, exerts local effects on cell growth and fibrogenesis. However, the signal transduction mechanisms underlying the effects of Aldo on hepatic fibrogenesis remain to be fully elucidated. The present study aims to investigate the signal transduction mechanism underlying the effects of Aldo on extracellular signal-regulated kinase 1/2 (ERK1/2), early growth response-1 (EGR-1) and on the platelet-derived growth factor-B (PDGF-B).

METHODSIn vitro, hepatic stellate cell (HSC)-T6 cell line was treated with Aldo for 10 min, 0.5 h, 1 h, 2 h and 3 h. Protein expression of phospho-p42/44 was detected by Western blot. In addition, HSC-T6 were preincubated for 1 h or not at all with U0126 (an inhibitor of the MAPK/ERK kinase), and antioxidant-N-acetylcysteine (NAC) prior to exposure to Aldo for the indicated times. Protein expressions of phospho-p42/44 and PDGF-B were measured by Western blot. DNA biding activity of EGR-1 was analyzed by electrophoretic gel mobility shift assay (EMSA). By means of immunohistochemistry, expression of PDGF-B was detected.

RESULTSAldo induced phospho-p42/44 expression could be abrogated by U0126; NAC did not inhibit phospho-p42/44 expression. Gel shift study showed that stimulation of HSC by Aldo markedly increased the EGR-1 DNA binding activity, which was abrogated by U0126, reaching a maximum at 60 minutes, and then declined progressively. NAC did not reduce the EGR-1 activity. Aldo increased the PDGF-B protein level in HSC, which was not attenuated by NAC and U0126.

CONCLUSIONSStimulation of HSC by Aldo results in activation of EGR-1 via ERK1/2 pathway, leading to up-regulation of PDGF-B expression.

Aldosterone ; pharmacology ; Cell Line ; Early Growth Response Protein 1 ; biosynthesis ; genetics ; Hepatocytes ; cytology ; metabolism ; Humans ; Mitogen-Activated Protein Kinase 3 ; biosynthesis ; genetics ; Proto-Oncogene Proteins c-sis ; biosynthesis ; genetics ; Signal Transduction

OBJECTIVETo investigate the mechanism of high transcription of the glial cell-line derived neurotrophic factor (gdnf) gene induced by hyperacetylation of histone H3 lysine 9 (H3K9) at its promoter region II in rat C6 glioma cells.

METHODSThe acetylation level of H3K9 at Egr-1 binding site in gdnf gene promoter region II and the binding capacity of Egr-1 to its binding site in gdnf promoter were examined by ChIP-PCR in C6 astroglioma cells and normal rat astrocytes, and its changes were investigated in C6 astroglioma cells after treatment with histone acetyltransferase inhibitor curcumin or deacetylase inhibitor trichostatin A.

RESULTSCompared normal astrocytes, C6 astroglioma cells showed significantly increased acetylation level of H3K9 at Egr-1 binding site in gdnf gene promoter region II and Egr-1 binding capacity (P<0.01). Curcumin treatment significantly reduced H3K9 acetylation level at Egr-1 binding site and decreased both the binding of Egr-1 to promoter region II and gdnf mRNA levels in C6 astroglioma cells (P<0.05). Conversely, increased H3K9 acetylation at the Egr-1 binding site induced by trichostatin A significantly increased the binding of Egr-1 to promoter region II and gdnf mRNA expression levels (P<0.05).

CONCLUSIONH3K9 hyperacetylation induces increased Egr-1 binding to gdnf gene promoter II, which might be the reason for the high transcription level of gdnf gene in rat C6 glioma cells.

Acetylation ; Animals ; Astrocytes ; metabolism ; Binding Sites ; Cell Line, Tumor ; Early Growth Response Protein 1 ; metabolism ; Glial Cell Line-Derived Neurotrophic Factor ; genetics ; Glioma ; metabolism ; Histones ; chemistry ; Promoter Regions, Genetic ; Protein Processing, Post-Translational ; RNA, Messenger ; Rats ; Transcription, Genetic

OBJECTIVETo investigate the expressions of inflammation- and fibrosis-related genes in perinephric and subcutaneous adipose tissues in patients with adrenocorticotropic hormone (ACTH)-independent Cushing's syndrome.

METHODSThe perinephric and subcutaneous adipose tissues adipose tissues were obtained from 8 patients with ACTH-independent Cushing's syndrome undergoing laparoscopic retroperitoneal adrenalectomy. Real-time PCR was used to detect the mRNA expression levels of interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), matrix metallopeptidase 2 (MMP-2), TIMP metallopeptidase inhibitor 1 (TIMP-1), early growth response 1 (EGR1), CCAAT/enhancer binding protein β(CEBPβ), uncoupling protein 1(UCP-1), PPARγ coactivator 1 alpha (PGC1α) and cell death-inducing DFFA-like effector a (CIDEA).

RESULTSThe mRNA level of CIDEA was significantly higher in the perinephric adipose tissue (peri-N) than in the subcutaneous adipose tissue (subQ) (P<0.05). The expressions of CEBPβ, UCP-1, and PGC1α mRNA in the peri-N were similar with those in the subQ. The expressions of IL-6, TIMP1 and EGR1 mRNA in the subQ were significantly higher than those in the peri-N (P<0.05). No significant difference in TNF-α and MMP-2 mRNA levels was found between peri-N and subQ.

CONCLUSIONThe expression levels of the inflammation- and fibrosis-related genes are higher in the subQ than in the peri-N of patients with ACTH-independent Cushing's syndrome, suggesting that chronic exposure to endogenous hypercortisolism may cause adipose tissue dysfunction.

Adrenalectomy ; Adrenocorticotropic Hormone ; CCAAT-Enhancer-Binding Protein-beta ; metabolism ; Cushing Syndrome ; metabolism ; surgery ; Early Growth Response Protein 1 ; metabolism ; Humans ; Matrix Metalloproteinase 2 ; metabolism ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; metabolism ; Real-Time Polymerase Chain Reaction ; Subcutaneous Fat ; metabolism ; Tissue Inhibitor of Metalloproteinase-1 ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism ; Uncoupling Protein 1 ; metabolism

PURPOSE: Exercise enhances memory function by increasing neurogenesis in the hippocampus, and circadian rhythms modulate synaptic plasticity in the hippocampus. The circadian rhythm-dependent effects of treadmill exercise on memory function in relation with neurogenesis were investigated using mice. METHODS: The step-down avoidance test was used to evaluate short-term memory, the 8-arm maze test was used to test spatial learning ability, and 5-bromo-2’-deoxyuridine immunofluorescence was used to assess neurogenesis. Western blotting was also performed to assess levels of synaptic plasticity-associated proteins, such as brain-derived neurotrophic factor, tyrosine kinase receptor B, phosphorylated cAMP response element-binding protein, early growth response protein 1, postsynaptic density protein 95, and growth-associated protein 43. The mice in the treadmill exercise at zeitgeber 1 group started exercising 1 hour after sunrise, the mice in the treadmill exercise at zeitgeber 6 group started exercising 6 hours after sunrise, and the mice in the treadmill exercise at zeitgeber 13 group started exercising 1 hour after sunset. The mice in the exercise groups were forced to run on a motorized treadmill for 30 minutes once a day for 7 weeks. RESULTS: Treadmill exercise improved short-term memory and spatial learning ability, and increased hippocampal neurogenesis and the expression of synaptic plasticity-associated proteins. These effects of treadmill exercise were stronger in mice that exercised during the day or in the evening than in mice that exercised at dawn. CONCLUSIONS: Treadmill exercise improved memory function by increasing neurogenesis and the expression of synaptic plasticity-associated proteins. These results suggest that the memory-enhancing effect of treadmill exercise may depend on circadian rhythm changes.
Animals ; Blotting, Western ; Brain-Derived Neurotrophic Factor ; Circadian Rhythm* ; Cyclic AMP Response Element-Binding Protein ; Early Growth Response Protein 1 ; Exercise Test ; Fluorescent Antibody Technique ; GAP-43 Protein ; Hippocampus ; Learning ; Memory* ; Memory, Short-Term ; Mice* ; Neurogenesis ; Neuronal Plasticity ; Post-Synaptic Density ; Protein-Tyrosine Kinases ; Spatial Learning