关键词： Abeliophyllum distichum Nakai   Activating transcription factor 3   Apoptosis   Cancer chemoprevention   Colorectal cancer  

摘要： Background: Recently, Abeliophyllum distichum Nakai (A. distichum) has been reported to exert the inhibitory effect on angiotensin converting enzyme. However, no specific pharmacological effects from A. distichum have been described. We performed in vitro study to evaluate anti-cancer properties of A. distichum and then elucidate the potential mechanisms. Methods: Cell viability was measured by MTT assay. ATF3 expression level was evaluated by Western blot or RT-PCR and ATF3 transcriptional activity was determined using a dual-luciferase assay kit after the transfection of ATF3 promoter constructs. In addition, ATF3-dependent apoptosis was evaluated by Western blot after ATF3 knockdown using ATF3 siRNA. Results: Exposure of ethyl acetate fraction from the parts of A. distichum including flower, leaf and branch to human colorectal cancer cells, breast cancer cells and hepatocellular carcinoma reduced the cell viability. The branch extracts from A. distichum (EAFAD-B) increased the expression of activating transcription factor 3 (ATF3) and promoter activity, indicating transcriptional activation of ATF3 gene by EAFAD-B. In addition, our data showed that EAFAD-B-responsible sites might be between -147 and -85 region of the ATF3 promoter. EAFAD-B-induced ATF3 promoter activity was significantly decreased when the CREB site was deleted. However, the deletion of Ftz sites did not affect ATF3 promoter activity by EAFAD-B. We also observed that inhibition of p38MAPK and GSK3 beta attenuated EAFAD-B-mediated ATF3 promoter activation. Also, EAFAD-B contributes at least in part to increase of ATF3 accumulation. Conclusion: These findings suggest that the anti-cancer activity of EAFAD-B may be a result of ATF3 promoter activation and subsequent increase of ATF3 expression.

关键词： S   pneumoniae   activating transcription factor (ATF3)   pneumonia   pneumococcal infection   TNF-alpha   IL-1 beta   IFN-gamma  

摘要： Background. Activating transcription factor-3 (ATF3) is known as a suppressor of cytokine production after exposure to lipopolysaccharide or during gram-negative bacterial infection. However, the mechanism by which ATF3 regulates innate immunity against gram-positive bacterial infection, particularly Streptococcus pneumoniae, remains unknown. Methods. The wild-type and ATF3 knock-out (KO) mice were infected intranasally (i.n) or intraperitoneally with S. pneumoniae, and bacterial colonization or survival rate was determined. Pneumococcal pneumonia was induced by i.n infection, and ATF3 level was determined by Western blot. ATF3 KO cells or ATF3 siRNA transfection were used to determine expression of ATF3 downstream genes. Enzyme-linked immunosorbent assay was used to examine cytokines levels. Results. ATF3 was highly expressed in various cell lines in vitro and in many organs in vivo. Pneumolysin was a novel inducer of ATF3. Pneumococcal infection induced ATF3, which subsequently stimulated production of cytokines (tumor necrosis factor [TNF]-alpha, interleukin [IL]-1 beta, and interferon [IFN]-gamma). ATF3-mediated cytokine induction protected the host from pneumococcal infection. In the pneumonia infection model, the bacterial clearance of wild-type mice was more efficient than those of ATF3 KO mice. Conclusions. Taken together, we can conclude that ATF3 regulates innate immunity positively upon pneumococcus infection by enhancing TNF-alpha, IL-1 beta, and IFN-gamma expression and modulating bacterial clearance.

关键词： Chronic obstructive pulmonary disease   Gene interaction networks   Extracellular matrix-related genes  

摘要： Chronic obstructive pulmonary disease (COPD) is a major public health problem worldwide and is proved to be the number three cause of death in globally. The objective of this study was to explore the molecular mechanism of the progression of COPD. Using the GSE1650 affymetrix microarray data accessible from Gene Expression Omnibus database, we first identified the differentially expressed genes (DEGs) between 18 COPD samples and 12 normal samples, followed by the GO / KEGG pathway analysis and gene interaction networks analysis of the DEGs. Our study identified 134 DEGs which involved in regulation of immune response, vesicle transport system, growth regulator and extracellular matrix (ECM)-related pathways. Gene interaction networks analysis showed that the sub-network involved by activating transcription factor-3 (ATF3) was the most significant sub-network in gene interaction networks. Furthermore, the investigation of extracellular matrix-related genes showed that genes like collagen and insulin-like growth factor binding protein could clearly distinguish the COPD and normal control. The genes regulated by ATF3 transcriptional activator as well as ECM-related genes may play an important role in the process of COPD. Our study provides a comprehensive bioinformatics analysis of genes and pathways which may be involved in the progression of COPD.

摘要： INTRODUCTION:Chronic obstructive pulmonary disease (COPD) is a major public health problem worldwide and is proved to be the number three cause of death in globally. The objective of this study was to explore the molecular mechanism of the progression of COPD. METHODS:Using the GSE1650 affymetrix microarray data accessible from Gene Expression Omnibus database, we first identified the differentially expressed genes (DEGs) between 18 COPD samples and 12 normal samples, followed by the GO / KEGG pathway analysis and gene interaction networks analysis of the DEGs. Our study identified 134 DEGs which involved in regulation of immune response, vesicle transport system, growth regulator and extracellular matrix (ECM)-related pathways. RESULTS:Gene interaction networks analysis showed that the sub-network involved by activating transcription factor-3 (ATF3) was the most significant sub-network in gene interaction networks. Furthermore, the investigation of extracellular matrix-related genes showed that genes like collagen and insulin-like growth factor binding protein could clearly distinguish the COPD and normal control. CONCLUSIONS:The genes regulated by ATF3 transcriptional activator as well as ECM-related genes may play an important role in the process of COPD. Our study provides a comprehensive bioinformatics analysis of genes and pathways which may be involved in the progression of COPD.

关键词： CGN   MIC-1   ATF3   Epithelial apoptosis  

摘要： Carrageenan (CGN), a widely used food additive, has been shown to injure the epithelial barrier in animal models. This type of damage is a clinical feature of inflammatory bowel disease (IBD) in humans. In the present study, the effects of CGN on pro-apoptotic responses associated with macrophage inhibitory cytokine 1 (MIC-1) regulation in human enterocytes were evaluated. CGN up-regulated the expression of MIC-1 that promoted epithelial cell apoptosis. Although MIC-1 induction was dependent on pro-apoptotic p53 protein, the pro-survival protein activating transcription factor 3 (ATF3) was negatively regulated by p53 expression. However, MIC-1 enhanced the expression of the pro-survival protein ATF3 in enterocytes exposed to CGN. Functionally, MIC-1-mediated epithelial cell apoptosis was counteracted by the pro-survival action of ATF3 in response to CGN exposure. These findings demonstrated that the counterbalance between MIC-1 and ATF3 is critical for deciding the fate of enterocytes under the food chemical stress. (C) 2014 Elsevier Ireland Ltd. All rights reserved.

关键词： Adipocyte differentiation   Activating transcription factor 3 (ATF3)   Peroxisome proliferator activated receptor gamma (PPAR gamma)   Promoter activity   ATF/CREB responsive element (ATF/CRE)  

摘要： Activating transcription factor 3 (ATF3) is a stress-adaptive transcription factor that mediates cellular stress response signaling. We previously reported that ATF3 represses CCAAT/enhancer binding protein a (C/EBP alpha) expression and inhibits 3T3-L1 adipocyte differentiation. In this study, we explored potential role of ATF3 in negatively regulating peroxisome proliferator activated receptor-gamma (PPAR gamma). ATF3 decreased the expression of PPAR gamma and its target gene in 3T3-L1 adipocytes. ATF3 also repressed the activity of -2.6 Kb promoter of mouse PPAR gamma 2. Overexpression of PPAR gamma significantly prevented the ATF3-mediated inhibition of 3T3-L1 differentiation. Transfection studies with 5' deleted-reporters showed that ATF3 repressed the activity of -2037 bp promoter, whereas it did not affect the activity of -1458 bp promoter, suggesting that ATF3 responsive element is located between the -2037 and -1458. An electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrated that ATF3 binds to ATF/CRE site (5'-TGACGTTT-3') between -1537 and -1530. Mutation of the ATF/CRE site abrogated ATF3-mediated transrepression of the PPAR gamma 2 promoter. Treatment with thapsigargin, endoplasmic reticulum (ER) stress inducer, increased ATF3 expression, whereas it decreased PPAR gamma expression. ATF3 knockdown significantly blocked the thapsigargin-mediated downregulation of PPAR gamma expression. Furthermore, overexpression of PPAR gamma prevented inhibition of 3T3-L1 differentiation by thapsigargin. Collectively, these results suggest that ATF3-mediated inhibition of PPAR gamma expression may contribute to inhibition of adipocyte differentiation during cellular stress including ER stress. (C) 2014 Elsevier Inc. All rights reserved.

关键词： 神经元凋亡   H3甲基化修饰   G9a   ATF3  

摘要： 目的探讨协同c-Jun/ATF2调控ATF3表达的染色质重塑事件及对神经元凋亡的作用。方法小脑颗粒神经元凋亡刺激后检测组蛋白H3乙酰化水平的变化与ATF3表达的变化。G9a抑制剂BIX-01294处理神经元,Western Blot检测ATF3的表达、H3的甲基化变化,核染色检测神经元的凋亡率。结果神经元凋亡时诱导ATF3表达,H3第4位赖氨酸乙酰化修饰(methyl-H3-K4)增加。BIX-01294浓度依赖地抑制H3第4位赖氨酸甲基化修饰,抑制ATF3表达,抑制神经元凋亡(P<0.05)。结论神经元凋亡时,G9a介导的H3第4位赖氨酸甲基化修饰调控ATF3表达及凋亡发生。

关键词： ATF3   Unfolded protein response   Ischemic preconditioning   Infarct size   inflammatory response  

摘要： Ischemic preconditioning (PC) is an adaptive response to transient myocardial ischemia that protects the heart from subsequent ischemia/reperfusion (I/R) injury. However, the mechanisms underlying its cardioprotective effects remain unclear. Myocardium of adult male C57/BL6 mice, preconditioned by 6 cycles of 4 minute coronary occlusion and reperfusion, showed nuclear translocation of ATF3 and ATF6 and PERK phosphorylation 30 min after PC. The abundance of ER proteins, ATF3 and ATF4 was increased 24 h after PC;however, there was no evidence of IRE-1 activation inliVT or ER-stress activated indicator (ERAI) mice expressing XBP-1-Venus fusion protein. PC-induced nuclear translocation of ATF3 was attenuated in transgenic mice with cardiac-restricted overexpression of inducible ATF6. Ischemic PC increased the abundance of inducible nitric oxide synthase, cyclooxygenase-2, heme oxygenase-1 and aldose reductase to levels similar between \NT and ATF3-null hearts;however, the increase in IL-6 and ICAM-1 was exaggerated in ATF3-null hearts. Genetic deletion of ATF3 did not increase infarct size in non-preconditioned hearts but abolished the cardioprotective effects of PC. Larger infarct size in preconditioned ATF3-null hearts was associated with greater neutrophil infiltration in the myocardium, but no ATF3-dependent changes in the total or relative abundance of inflammatory monocytes were observed. Ischemic PC activates the unfolded protein response (UPR) and the activation of ATF3 by ER stress is essential for the cardioprotective effects of late PC. (c) 2014 Elsevier Ltd. All rights reserved.

关键词： NATURAL immunity   TRANSCRIPTION factors   ANTIGENS   HOMEOSTASIS   CELLULAR signal transduction   INFLAMMATION -- Mediators   CYTOKINES  

摘要： Our body is continuously exposed to a diverse array of infectious agents, foreign antigens, and host-derived danger signals. The innate immune system plays a vital role as the first line of defence against these insults by protecting the host from infection and maintaining tissue homeostasis. Families of signalling receptors (e.g. TLRs) recognize invading microbes and co-ordinate an appropriate inflammatory response via the production of pro-inflammatory cytokines and type I interferons (IFNs) to clear infection. However, inappropriate activation of innate immune receptors and unregulated production of inflammatory mediators is thought to be the basis for many acute and chronic inflammatory conditions. Indeed, excessive IFN production is implicated in the pathogenesis of lupus and atherosclerosis. Maintaining a balance between the beneficial and detrimental effects of IFNs is therefore crucial and their production must be tightly regulated. Yet these precise regulatory mechanisms remain poorly understood. We have discovered that macrophages deficient in the transcriptional modulator, ATF3, display significantly greater IFN β production following activation of TLRs and other innate immune receptors, as well as reduced LCMV viral infection. In contrast, overexpression of ATF3 in macrophages reduced the induction of IFN β and increased viral replication. Utilizing a range of molecular biology, biochemical and immunological techniques, integrated with powerful bioinformatics approaches we have investigated the molecular mechanisms responsible for ATF3-mediated regulation of IFN β . Our ATF3 ChIP-seq data has revealed that ATF3 regulates IFN β by binding directly to its promoter. Furthermore, we have found that ATF3 itself is regulated by IFNs and thus forms part of a negative feedback loop during the induction of IFN signalling. Together our findings indicate ATF3 is a critical regulator of the IFN innate immune response. A better understanding of how the innate immune

关键词： LIVER -- Cancer -- Prevention   STAT proteins   GENETIC transcription -- Regulation   CREB protein   CARRIER proteins   SPECTRIN  

摘要： The cytoskeletal protein Spectrin, beta, non-erythrocytic 1(SPTBN1), an adapter protein to SMAD3 in TCF-beta signaling, may prevent hepatocellular carcinoma (HCC) development by downregulating the expression of signal transducer and activator of transcription 3 (STAT3). To elucidate the as yet undefined mechanisms that regulate this process, we demonstrate that higher levels of STAT3 transcription are found in livers of heterozygous SPTBN1(+/-) mice as compared to that of wild type mice. We also found increased levels of ST4T3 mRNA, STAT3 protein, and p-STAT3 in human HCC cell-lines after knockdown of SPTBN1 or SMAD3, which promoted cell colony formation. Inhibition of STAT3 overrode the increase in cell colony formation due to knockdown of SPTBN1 or SMAD3. We also found that inhibition of SPTBN1 or SMAD3 upregulated STAT3 promoter activity in HCC cell-lines, which is dependent upon the cAMP-response element (CRE) and STAT-binding element (SHE) sites of the STAT3 promoter. Mechanistically, suppression of SPTHN1 and SMAD3 augmented the transcription of STAT3 by upregulating the CRE-binding proteins ATF3 and CREB2 and augmented the binding of those proteins to the regions within or upstream of the CRE site of the STAT3 promoter. Finally, in human HCC tissues, SPTBN1 expression correlated negatively with expression levels of STAT3, ATF3, and CREB2;SMAD3 expression correlated negatively with STAT3 expression;and the level of phosphorylated SMAD3 (p-SMAD3) correlated negatively with ATF3 and CREB2 protein levels. SPTBN1 and SMAD3 collaborate with CRE-binding transcription factors to inhibit STAT3, thereby preventing HCC development.