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Sample records for ap-1 transcriptional activity

  1. The AP-1 transcription factor homolog Pf-AP-1 activates transcription of multiple biomineral proteins and potentially participates in Pinctada fucata biomineralization.

    PubMed

    Zheng, Xiangnan; Cheng, Minzhang; Xiang, Liang; Liang, Jian; Xie, Liping; Zhang, Rongqing

    2015-09-25

    Activator protein-1 (AP-1) is an important bZIP transcription factor that regulates a series of physiological processes by specifically activating transcription of several genes, and one of its well-chartered functions in mammals is participating in bone mineralization. We isolated and cloned the complete cDNA of a Jun/AP-1 homolog from Pinctada fucata and called it Pf-AP-1. Pf-AP-1 had a highly conserved bZIP region and phosphorylation sites compared with those from mammals. A tissue distribution analysis showed that Pf-AP-1 was ubiquitously expressed in P. fucata and the mRNA level of Pf-AP-1 is extremely high in mantle. Pf-AP-1 expression was positively associated with multiple biomineral proteins in the mantle. The luciferase reporter assay in a mammalian cell line showed that Pf-AP-1 significantly up-regulates the transcriptional activity of the promoters of KRMP, Pearlin, and Prisilkin39. Inhibiting the activity of Pf-AP-1 depressed the expression of multiple matrix proteins. Pf-AP-1 showed a unique expression pattern during shell regeneration and pearl sac development, which was similar to the pattern observed for biomineral proteins. These results suggest that the Pf-AP-1 AP-1 homolog is an important transcription factor that regulates transcription of several biomineral proteins simultaneously and plays a role in P. fucata biomineralization, particularly during pearl and shell formation.

  2. Human ZCCHC12 activates AP-1 and CREB signaling as a transcriptional co-activator.

    PubMed

    Li, Hong; Liu, Qian; Hu, Xiang; Feng, Du; Xiang, Shuanglin; He, Zhicheng; Hu, Xingwang; Zhou, Jianlin; Ding, Xiaofeng; Zhou, Chang; Zhang, Jian

    2009-07-01

    Mouse zinc finger CCHC domain containing 12 gene (ZCCHC12) has been identified as a transcriptional co-activator of bone morphogenetic protein (BMP) signaling, and human ZCCHC12 was reported to be related to non-syndromic X-linked mental retardation (NS-XLMR). However, the details of how human ZCCHC12 involve in the NS-XLMR still remain unclear. In this study, we identified a novel nuclear localization signal (NLS) in the middle of human ZCCHC12 protein which is responsible for the nuclear localization. Multiple-tissue northern blot analysis indicated that ZCCHC12 is highly expressed in human brain. Furthermore, in situ hybridization showed that ZCCHC12 is specifically expressed in neuroepithelium of forebrain, midbrain, and diencephalon regions of mouse E10.5 embryos. Luciferase reporter assays demonstrated that ZCCHC12 enhanced the transcriptional activities of activator protein 1 (AP-1) and cAMP response element binding protein (CREB) as a coactivator. In conclusion, we identified a new NLS in ZCCHC12 and figured out that ZCCHC12 functions as a transcriptional co-activator of AP-1 and CREB.

  3. The novel secretory protein CGREF1 inhibits the activation of AP-1 transcriptional activity and cell proliferation.

    PubMed

    Deng, Weiwei; Wang, Lan; Xiong, Ying; Li, Jing; Wang, Ying; Shi, Taiping; Ma, Dalong

    2015-08-01

    The transcription factor AP-1 plays an important role in inflammation and cell survival. Using a dual-luciferase reporter assay system and a library of 940 candidate human secretory protein cDNA clones, we identified that CGREF1 can inhibit the transcriptional activity of AP-1. We demonstrated that CGREF1 is secreted via the classical secretory pathway through the ER-to-Golgi apparatus. Functional investigations revealed that overexpression of CGREF1 can significantly inhibit the phosphorylation of ERK and p38 MAPK, and suppress the proliferation of HEK293T and HCT116 cells. Conversely, specific siRNAs against CGREF1 can increase the transcriptional activity of AP-1. These results clearly indicated that CGREF1 is a novel secretory protein, and plays an important role in regulation of AP-1 transcriptional activity and cell proliferation.

  4. Impaired dynamin 2 function leads to increased AP-1 transcriptional activity through the JNK/c-Jun pathway.

    PubMed

    Szymanska, Ewelina; Skowronek, Agnieszka; Miaczynska, Marta

    2016-01-01

    Activation of AP-1 transcription factors, composed of the Jun and Fos proteins, regulates cellular fates, such as proliferation, differentiation or apoptosis. Among other stimuli, the AP-1 pathway can be initiated by extracellular ligands, such as growth factors or cytokines, which undergo internalization in complex with their receptors. Endocytosis has been implicated in the regulation of several signaling pathways; however its possible impact on AP-1 signaling remains unknown. Here we show that inhibition of dynamin 2 (Dyn2), a major regulator of endocytic internalization, strongly stimulates the AP-1 pathway. Specifically, expression of a dominant-negative Dyn2 K44A mutant increases the total levels of c-Jun, its phosphorylation on Ser63/73 and transcription of AP-1 target genes. Interestingly, DNM2 mutations implicated in human neurological disorders exhibit similar effects on AP-1 signaling. Mechanistically, Dyn2 K44A induces AP-1 by increasing phosphorylation of several receptor tyrosine kinases. Their activation is required to initiate a Src- and JNK-dependent signaling cascade converging on c-Jun and stimulating expression of AP-1 target genes. Cumulatively, our data uncover a link between the Dyn2 function and JNK signaling which leads to AP-1 induction.

  5. Temporal coherency between receptor expression, neural activity and AP-1-dependent transcription regulates Drosophila motoneuron dendrite development.

    PubMed

    Vonhoff, Fernando; Kuehn, Claudia; Blumenstock, Sonja; Sanyal, Subhabrata; Duch, Carsten

    2013-02-01

    Neural activity has profound effects on the development of dendritic structure. Mechanisms that link neural activity to nuclear gene expression include activity-regulated factors, such as CREB, Crest or Mef2, as well as activity-regulated immediate-early genes, such as fos and jun. This study investigates the role of the transcriptional regulator AP-1, a Fos-Jun heterodimer, in activity-dependent dendritic structure development. We combine genetic manipulation, imaging and quantitative dendritic architecture analysis in a Drosophila single neuron model, the individually identified motoneuron MN5. First, Dα7 nicotinic acetylcholine receptors (nAChRs) and AP-1 are required for normal MN5 dendritic growth. Second, AP-1 functions downstream of activity during MN5 dendritic growth. Third, using a newly engineered AP-1 reporter we demonstrate that AP-1 transcriptional activity is downstream of Dα7 nAChRs and Calcium/calmodulin-dependent protein kinase II (CaMKII) signaling. Fourth, AP-1 can have opposite effects on dendritic development, depending on the timing of activation. Enhancing excitability or AP-1 activity after MN5 cholinergic synapses and primary dendrites have formed causes dendritic branching, whereas premature AP-1 expression or induced activity prior to excitatory synapse formation disrupts dendritic growth. Finally, AP-1 transcriptional activity and dendritic growth are affected by MN5 firing only during development but not in the adult. Our results highlight the importance of timing in the growth and plasticity of neuronal dendrites by defining a developmental period of activity-dependent AP-1 induction that is temporally locked to cholinergic synapse formation and dendritic refinement, thus significantly refining prior models derived from chronic expression studies.

  6. Arsenic Directly Binds to and Activates the Yeast AP-1-Like Transcription Factor Yap8

    SciTech Connect

    Kumar, Nallani Vijay; Yang, Jianbo; Pillai, Jitesh K.; Rawat, Swati; Solano, Carlos; Kumar, Abhay; Grøtli, Morten; Stemmler, Timothy L.; Rosen, Barry P.; Tamás, Markus J.

    2015-12-28

    The AP-1-like transcription factor Yap8 is critical for arsenic tolerance in the yeastSaccharomyces cerevisiae. However, the mechanism by which Yap8 senses the presence of arsenic and activates transcription of detoxification genes is unknown. Here we demonstrate that Yap8 directly binds to trivalent arsenite [As(III)]in vitroandin vivoand that approximately one As(III) molecule is bound per molecule of Yap8. As(III) is coordinated by three sulfur atoms in purified Yap8, and our genetic and biochemical data identify the cysteine residues that form the binding site as Cys132, Cys137, and Cys274. As(III) binding by Yap8 does not require an additional yeast protein, and Yap8 is regulated neither at the level of localization nor at the level of DNA binding. Instead, our data are consistent with a model in which a DNA-bound form of Yap8 acts directly as an As(III) sensor. Binding of As(III) to Yap8 triggers a conformational change that in turn brings about a transcriptional response. Thus, As(III) binding to Yap8 acts as a molecular switch that converts inactive Yap8 into an active transcriptional regulator. This is the first report to demonstrate how a eukaryotic protein couples arsenic sensing to transcriptional activation.

  7. Arsenic Directly Binds to and Activates the Yeast AP-1-Like Transcription Factor Yap8.

    PubMed

    Kumar, Nallani Vijay; Yang, Jianbo; Pillai, Jitesh K; Rawat, Swati; Solano, Carlos; Kumar, Abhay; Grøtli, Morten; Stemmler, Timothy L; Rosen, Barry P; Tamás, Markus J

    2015-12-28

    The AP-1-like transcription factor Yap8 is critical for arsenic tolerance in the yeast Saccharomyces cerevisiae. However, the mechanism by which Yap8 senses the presence of arsenic and activates transcription of detoxification genes is unknown. Here we demonstrate that Yap8 directly binds to trivalent arsenite [As(III)] in vitro and in vivo and that approximately one As(III) molecule is bound per molecule of Yap8. As(III) is coordinated by three sulfur atoms in purified Yap8, and our genetic and biochemical data identify the cysteine residues that form the binding site as Cys132, Cys137, and Cys274. As(III) binding by Yap8 does not require an additional yeast protein, and Yap8 is regulated neither at the level of localization nor at the level of DNA binding. Instead, our data are consistent with a model in which a DNA-bound form of Yap8 acts directly as an As(III) sensor. Binding of As(III) to Yap8 triggers a conformational change that in turn brings about a transcriptional response. Thus, As(III) binding to Yap8 acts as a molecular switch that converts inactive Yap8 into an active transcriptional regulator. This is the first report to demonstrate how a eukaryotic protein couples arsenic sensing to transcriptional activation.

  8. Arsenic Directly Binds to and Activates the Yeast AP-1-Like Transcription Factor Yap8

    PubMed Central

    Kumar, Nallani Vijay; Yang, Jianbo; Pillai, Jitesh K.; Rawat, Swati; Solano, Carlos; Kumar, Abhay; Grøtli, Morten; Stemmler, Timothy L.; Rosen, Barry P.

    2015-01-01

    The AP-1-like transcription factor Yap8 is critical for arsenic tolerance in the yeast Saccharomyces cerevisiae. However, the mechanism by which Yap8 senses the presence of arsenic and activates transcription of detoxification genes is unknown. Here we demonstrate that Yap8 directly binds to trivalent arsenite [As(III)] in vitro and in vivo and that approximately one As(III) molecule is bound per molecule of Yap8. As(III) is coordinated by three sulfur atoms in purified Yap8, and our genetic and biochemical data identify the cysteine residues that form the binding site as Cys132, Cys137, and Cys274. As(III) binding by Yap8 does not require an additional yeast protein, and Yap8 is regulated neither at the level of localization nor at the level of DNA binding. Instead, our data are consistent with a model in which a DNA-bound form of Yap8 acts directly as an As(III) sensor. Binding of As(III) to Yap8 triggers a conformational change that in turn brings about a transcriptional response. Thus, As(III) binding to Yap8 acts as a molecular switch that converts inactive Yap8 into an active transcriptional regulator. This is the first report to demonstrate how a eukaryotic protein couples arsenic sensing to transcriptional activation. PMID:26711267

  9. Activation of transcription factor AP-1 and mitogen-activated protein kinases in aniline-induced splenic toxicity

    SciTech Connect

    Khan, M. Firoze . E-mail: mfkhan@utmb.edu; Kannan, Subburaj; Wang Jianling

    2006-01-15

    Signaling mechanisms in aniline-induced fibrogenic and/or tumorigenic response in the spleen are not known. Previous studies have shown that aniline exposure leads to iron accumulation and oxidative stress in the spleen, which may cause activation of redox-sensitive transcription factors and regulate the transcription of genes involved in fibrosis and/or tumorigenesis. To test this, male SD rats were treated with 0.5 mmol/kg/day aniline via drinking water for 30 days, and activation of transcription factor AP-1 was determined in the splenocyte nuclear extracts (NEs). AP-1 DNA-binding activity in the NEs of freshly isolated splenocytes from aniline-treated rats increased in comparison to the controls, as determined by electrophoretic mobility shift assay (EMSA). AP-1 binding was also determined in the NEs of cultured splenocytes (2 h and 24 h), which showed even a greater increase in binding activity at 2 h. The specificity of AP-1 binding for relevant DNA motifs was confirmed by competition EMSA and by supershift EMSA using antibodies specific to c-Jun and c-Fos. To further explore the signaling mechanisms in the AP-1 activation, phosphorylation patterns of mitogen-activated protein kinases (MAPKs) were pursued. Aniline exposure induced increases in the phosphorylation of the three classes of MAPKs: extracellular-signal-regulated kinase (ERK 1/2), c-Jun N-terminal kinase (JNK 1/2), and p38 MAPKs. Furthermore, TGF-{beta}1 mRNA expression showed a 3-fold increase in the spleens of aniline-treated rats. These observations suggest a strong association among MAPK phosphorylation, AP-1 activation, and enhanced TGF-{beta}1 gene expression. The observed sequence of events subsequent to aniline exposure could regulate genes that lead to fibrogenic and/or tumorigenic response in the spleen.

  10. Cloning and expression of a transcription factor activator protein-1 (AP-1) member identified from manila clam Venerupis philippinarum.

    PubMed

    Wu, Luning; Zhang, Lei; Zhao, Jianmin; Ning, Xuanxuan; Mu, Changkao; Wang, Chunlin

    2015-02-15

    The transcription factor activator protein-1 (AP-1) proteins are implicated to play a major role in the regulation of numerous genes involved in the function and development of the immune system, cell differentiation, proliferation, apoptosis, etc. It can bind to promoter of its target genes in a sequence-specific manner to transactivate or repress them. In this study, the full-length cDNA of an AP-1 was identified from Venerupis philippinarum (denoted as VpAP-1) by EST analysis and RACE approaches. Phylogenetic analysis indicated that VpAP-1 had higher evolutional conservation to invertebrate than vertebrate counterparts and should be a new member of the AP-1 protein family. Spatial expression analysis found that VpAP-1 transcript was most abundantly expressed in the hemocytes and hepatopancreas, weakly expressed in the tissues of the gills, mantle and muscle. After Vibrio anguillarum challenge, the expression of VpAP-1 transcript in overall hemocyte population was up-regulated in the first 6h, and then decreased to 1.5-fold of the control group at 12h. As time progressed, a second peak of VpAP-1 expression was detected at 24h post-infection, which was 5-fold compared with that of the control group (P<0.01). After that, the expression level was sharply decreased and dropped to 0.5-fold of the control at 96h. The above results indicated that VpAP-1 was perhaps involved in the immune responses against microbe infection and might be contributed to the clearance of bacterial pathogens.

  11. Activation of transcription factor AP-1 in response to thermal injury in rat small intestine and IEC-6 cells.

    PubMed

    Zhang, Yonghong; Zhao, Hong; Liu, Tao; Wan, Changrong; Liu, Xiaoxi; Gao, Zhimin; Hou, Xiaolin; Jiang, Linshu; Liu, Fenghua

    2015-07-11

    Our previous studies indicated that heat stress can cause significant damage to the intestinal epithelium and induce differential expression of many genes in rat small intestine. The transcription factors AP-1 and NF-κB, which act as important mediators by binding to specific DNA sequences within gene promoters, regulate the transcription of genes associated with immune regulation, stress response and cell fate. To determine whether AP-1 and NF-κB are involved in hyperthermia-induced injury in rat small intestine and IEC-6 cells, we investigated their activity, and the expression of related proteins, by electrophoretic mobility shift assays and western blotting, respectively. Heat stress resulted in severe damage to the epithelium of the small intestine. The cell morphology and viability were obviously altered when IEC-6 cell was exposed to hyperthermia. AP-1 was activated in the small intestine of heat-stressed rats, as was phosphorylation of the JNK signaling pathway. In IEC-6 cell line, AP-1 activation in groups exposed to 42 °C for 1 h, 2 h and 4 h was significantly increased. In contrast, NF-κB was not activated in both in vivo and in vitro models. These results reveal that AP-1 is likely to play an important role in regulating gene transcription in rat small intestine and IEC-6 cells during exposure to heat stress.

  12. Expression of the leukocyte early activation antigen CD69 is regulated by the transcription factor AP-1.

    PubMed

    Castellanos, M C; Muñoz, C; Montoya, M C; Lara-Pezzi, E; López-Cabrera, M; de Landázuri, M O

    1997-12-01

    The leukocyte Ag CD69, one of the earliest cell surface activation Ags, is up-regulated at the transcriptional level by proinflammatory stimuli involving the NF-kappaB/Rel family of transcription factors. However, promoter fragments lacking a critical kappaB motif respond to other stimuli such as phorbol esters and triggering Abs against TCR/CD3. Since the 5' promoter flanking region of the CD69 gene contains several putative binding sequences for transcription factor activating protein-1 (AP-1), we explored its role in the inducible expression of CD69. Stimuli that induce AP-1, but not NF-kappaB, such as pyrrolidine dithiocarbamate, augmented the cell surface expression of CD69 as well as its mRNA levels, and the promoter activity of the CD69 gene. This up-regulation is accompanied by an increased binding of jun and fos family members to a consensus AP-1 binding site of the proximal (-16) CD69 promoter region, which seems to be functionally responsive to different activation signals and is trans activated by c-jun expression vectors. Furthermore, cotransfection of a dominant negative version of c-jun, but not IkappaB, abolished the inducible transcriptional activity of the CD69 promoter. In conclusion, the inducible expression of the CD69 gene by mitogenic signals is regulated by the transcription factor AP-1.

  13. The Synonymous Ala87 Mutation of Estrogen Receptor Alpha Modifies Transcriptional Activation Through Both ERE and AP1 Sites.

    PubMed

    Fernández-Calero, Tamara; Flouriot, Gilles; Marín, Mónica

    2016-01-01

    Estrogen receptor α (ERα) exerts regulatory actions through genomic mechanisms. In the classical pathway, ligand-activated ERα binds directly to DNA through estrogen response elements (ERE) located in the promoter of target genes. ERα can also exert indirect regulation of transcription via protein-protein interaction with other transcription factors such as AP-1.S everal ERα synonymous polymorphisms have been identified and efforts to understand their implications have been made. Nevertheless effects of synonymous polymorphisms are still neglected. This chapter focuses on the experimental procedure employed in order to characterize the transcriptional activity of a synonymous polymorphism of the ERα (rs746432) called Alanine 87 (Ala87). Activity of both WT and Ala87 ERα isoforms on transcriptional pathways can be analyzed in transiently transfected cells using different reporter constructs. ERα efficiency on the classical genomic pathway can be analyzed by determining its transactivation activity on an ERE-driven thymidine kinase (TK) promoter controlling the expression of the luciferase reporter gene. Transcriptional activity through the indirect genomic pathway can be analyzed by employing an AP-1 DNA response element-driven promoter also controlling the expression of luciferase reporter gene.

  14. Activation of transcriptional activities of AP-1 and SRE by a new zinc-finger protein ZNF641

    SciTech Connect

    Qi Xingzhu; Li Yongqing; Xiao Jing; Yuan Wuzhou; Yan Yan; Wang Yuequn; Liang Shuyuan; Zhu Chuanbing; Chen Yingduan; Liu Mingyao . E-mail: mliu@ibt.tamhsc.edu; Wu Xiushan

    2006-01-27

    Mitogen-activated protein kinases (MAPKs) are evolutionarily conserved enzymes in cell signal transduction connecting cell-surface receptors to critical regulatory targets within cells and control cell survival, adaptation, and proliferation. Previous studies revealed that zinc-finger proteins are involved in the regulation of the MAPK signaling pathways. Here, we report the identification and characterization of a novel human zinc-finger protein, ZNF641. The cDNA of ZNF641 is 4.9 kb, encoding 438 amino acids in the nucleus. The protein is highly conserved in evolution across different vertebrate species from mouse to human. Northern blot analysis indicates that ZNF641 is expressed in most of the examined human tissues, with a high level in skeletal muscle. Overexpression of pCMV-Tag2B-ZNF641 in the COS-7 cells activates the transcriptional activities of AP-1 and SRE. Deletion analysis indicates that the linker between KRAB box and C{sub 2}H{sub 2}-type zinc-fingers represents the basal activation domain. These results suggest that ZNF641 may be a positive regulator in MAPK-mediated signaling pathways that lead to the activation of AP-1 and SRE.

  15. First molluscan transcription factor activator protein-1 (Ap-1) member from disk abalone and its expression profiling against immune challenge and tissue injury.

    PubMed

    De Zoysa, Mahanama; Nikapitiya, Chamilani; Lee, Youngdeuk; Lee, Sukkyoung; Oh, Chulhong; Whang, Ilson; Yeo, Sang-Yeop; Choi, Cheol Young; Lee, Jehee

    2010-12-01

    The regulation of transcriptional activation is an essential and critical point in gene expression. In this study, we describe a novel transcription factor activator protein-1 (Ap-1) gene from disk abalone Haliotis discus discus (AbAp-1) for the first time in mollusk. It was identified by homology screening of an abalone normalized cDNA library. The cloned AbAp-1 consists of a 945 bp coding region that encodes a putative protein containing 315 amino acids. The AbAp-1 gene is composed of a characteristic Jun transcription factor domain and a highly conserved basic leucine zipper (bZIP) signature similar to known Ap-1 genes. The AbAp-1 shares 46, 43 and, 40% amino acid identities with fish (Takifugu rubripes), human and insect (Ixodes scapularis) Ap-1, respectively. Quantitative real time RT-PCR analysis confirmed that AbAp-1 gene expression is constitutive in all selected tissues. AbAp-1 was upregulated in gills after bacteria (Vibrio alginolyticus, Vibrio parahemolyticus and Lysteria monocytogenes) challenge; and, upregulated in hemocytes and gills by viral hemorrhagic septicemia virus (VHSV) challenge. Shell damage and tissue injury also increased the transcriptional level of Ap-1 in mantle together with other transcription factors (NF-kB, LITAF) and pro-inflammatory TNF-α. All results considered, identification and gene expression data demonstrate that abalone Ap-1 is an important regulator in innate immune response against bacteria and virus, as well as in the inflammatory response during tissue injury. In addition, stimulation of Ap-1 under different external stimuli could be useful to understand the Ap-1 biology and its downstream target genes, especially in abalone-like mollusks. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. ZNF435, a novel human SCAN-containing zinc finger protein, inhibits AP-1-mediated transcriptional activation.

    PubMed

    Gu, Xing; Zheng, Mei; Fei, Xiangwei; Yang, Zhenxing; Li, Fan; Ji, Chaoneng; Xie, Yi; Mao, Yumin

    2007-06-30

    Zinc finger transcription factor genes are a significant fraction of the genes in the vertebrate genome. Here we report the isolation and characterization of a human zinc finger-containing gene, ZNF435, from a fetal brain cDNA library. ZNF435 cDNA is 1290 base pairs in length and contains an open reading frame encoding 349 amino acids with four C2H2-type zinc fingers at its carboxyl terminus and a SCAN motif at its amino terminus. RT-PCR results showed that ZNF435 was expressed in all tested tissues. A ZNF435-GFP fusion protein was located in the nucleus and the four zinc fingers acted as nuclear localization signals (NLSs). ZNF435 was found to be capable of homo-association, and this effect was independent of its zinc fingers. Furthermore, ZNF435 proved to be a transcription repressor as its overexpression in AD293 cells inhibited the transcriptional activities of AP-1.

  17. Antioxidants and AP-1 activation: a brief overview.

    PubMed

    Gomez del Arco, P; Martínez-Martínez, S; Calvo, V; Armesilla, A L; Redondo, J M

    1997-12-01

    Activity of the transcription factor AP-1 is controlled by different MAPK cascades that regulate the different AP-1 components at the transcriptional and posttranscriptional level. Recently, AP-1 has been shown to behave as a redox-sensitive transcription factor that can be induced under both pro-oxidative and antioxidative conditions. In this overview we summarize the signaling pathways that converge on the activation of AP-1 and the components of these pathways that have been shown to be targets of antioxidants. The activation of AP-1 by antioxidants may account for the expression of a number of genes that mediate important functions under physiological conditions.

  18. Anticancer activity of Phyllanthus emblica Linn. (Indian gooseberry): inhibition of transcription factor AP-1 and HPV gene expression in cervical cancer cells.

    PubMed

    Mahata, Sutapa; Pandey, Arvind; Shukla, Shirish; Tyagi, Abhishek; Husain, Syed Akhtar; Das, Bhudev Chandra; Bharti, Alok Chandra

    2013-01-01

    Plant products of Phyllanthus emblica Linn. are traditionally consumed for its immense nutritive and medicinal values. However, the molecular mechanism(s) by which it exerts it effects is less understood. In this study, we investigated mechanism of action of P. emblica fruit extract (PE) by studying its effect on activator protein-1 (AP-1) activity and human papillomavirus (HPV) transcription that are essential for tumorigenicity of cervical cancer cells. PE resulted in a dose-and time-dependent inhibition of DNA binding activity of constitutively active AP-1 in both HPV16-positive (SiHa) and HPV18-positive (HeLa) cervical cancer cells. PE-induced AP-1 inhibition was found mediated through downregulation of constituent AP-1 proteins, c-Jun, JunB, JunD, and c-Fos; however, the kinetics of their inhibition varied in both the cell types. Inhibition of AP-1 by PE was accompanied by suppression of viral transcription that resulted in growth inhibition of cervical cancer cells. Growth inhibitory activity of PE was primarily manifested through induction of apoptotic cell death. These results suggest that P. emblica exhibits its anticancer activities through inhibition of AP-1 and targets transcription of viral oncogenes responsible for development and progression of cervical cancer thus indicating its possible utility for treatment of HPV-induced cervical cancers.

  19. Inhibition of transcriptional activities of AP-1 and c-Jun by a new zinc finger protein ZNF394.

    PubMed

    Huang, Chunxia; Wang, Yuequn; Li, Dali; Li, Yongqing; Luo, Jian; Yuan, Wuzhou; Ou, Ying; Zhu, Chuanbing; Zhang, Yuejuan; Wang, Zhi; Liu, Mingyao; Wu, Xiushan

    2004-08-06

    Zinc finger proteins play important roles in a variety of cellular functions, including cell growth, proliferation, apoptosis, and intracellular signal transduction, and the zinc finger-containing transcription factor has been implicated as a critical regulator of multiple cardiac-expressed genes as well as a regulator of inducible gene expression in response to hypertrophic stimulation. With the aim of identifying the genes involved in human heart development and diseases, we have isolated a novel LER-related zinc finger gene named ZNF394 from human heart cDNA library. ZNF394 gene has a predicted 561-amino acid open reading frame, encoding a 64kDa zinc finger protein. The N-terminus of ZNF394 protein has a leucine-rich region (LER or SCAN domain), followed by a well-conserved krüppel-associated box domain. The C-terminus of the protein contains 7 C2H2 zinc finger motifs in tandem arrays with the highly conserved space region of the H/C-link. ZNF394 gene is mapped to chromosome 7q11.21. Northern blot analysis indicates that a 2.18kb transcript specific for ZNF394 is specifically expressed in the heart, skeletal muscle, and brain in human adult tissues. ZNF394 protein is expressed in cell nucleus. Overexpression of ZNF394 in the cell inhibits the transcriptional activities of c-Jun and AP-1 reporters, suggesting that ZNF394 is a new transcriptional repressor in mitogen-activated protein kinase signaling pathways and may play an important role in cardiac development and/or cardiac function.

  20. Tead and AP1 Coordinate Transcription and Motility.

    PubMed

    Liu, Xiangfan; Li, Huapeng; Rajurkar, Mihir; Li, Qi; Cotton, Jennifer L; Ou, Jianhong; Zhu, Lihua J; Goel, Hira L; Mercurio, Arthur M; Park, Joo-Seop; Davis, Roger J; Mao, Junhao

    2016-02-09

    The Tead family transcription factors are the major intracellular mediators of the Hippo-Yap pathway. Despite the importance of Hippo signaling in tumorigenesis, Tead-dependent downstream oncogenic programs and target genes in cancer cells remain poorly understood. Here, we characterize Tead4-mediated transcriptional networks in a diverse range of cancer cells, including neuroblastoma, colorectal, lung, and endometrial carcinomas. By intersecting genome-wide chromatin occupancy analyses of Tead4, JunD, and Fra1/2, we find that Tead4 cooperates with AP1 transcription factors to coordinate target gene transcription. We find that Tead-AP1 interaction is JNK independent but engages the SRC1-3 co-activators to promote downstream transcription. Furthermore, we show that Tead-AP1 cooperation regulates the activity of the Dock-Rac/CDC42 module and drives the expression of a unique core set of target genes, thereby directing cell migration and invasion. Together, our data unveil a critical regulatory mechanism underlying Tead- and AP1-controlled transcriptional and functional outputs in cancer cells. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Small Molecule Inhibitors Targeting Activator Protein 1 (AP-1)

    PubMed Central

    2015-01-01

    Activator protein 1 (AP-1) is a pivotal transcription factor that regulates a wide range of cellular processes including proliferation, apoptosis, differentiation, survival, cell migration, and transformation. Accumulating evidence supports that AP-1 plays an important role in several severe disorders including cancer, fibrosis, and organ injury, as well as inflammatory disorders such as asthma, psoriasis, and rheumatoid arthritis. AP-1 has emerged as an actively pursued drug discovery target over the past decade. Excitingly, a selective AP-1 inhibitor T-5224 (51) has been investigated in phase II human clinical trials. Nevertheless, no effective AP-1 inhibitors have yet been approved for clinical use. Despite significant advances achieved in understanding AP-1 biology and function, as well as the identification of small molecules modulating AP-1 associated signaling pathways, medicinal chemistry efforts remain an urgent need to yield selective and efficacious AP-1 inhibitors as a viable therapeutic strategy for human diseases. PMID:24831826

  2. Small molecule inhibitors targeting activator protein 1 (AP-1).

    PubMed

    Ye, Na; Ding, Ye; Wild, Christopher; Shen, Qiang; Zhou, Jia

    2014-08-28

    Activator protein 1 (AP-1) is a pivotal transcription factor that regulates a wide range of cellular processes including proliferation, apoptosis, differentiation, survival, cell migration, and transformation. Accumulating evidence supports that AP-1 plays an important role in several severe disorders including cancer, fibrosis, and organ injury, as well as inflammatory disorders such as asthma, psoriasis, and rheumatoid arthritis. AP-1 has emerged as an actively pursued drug discovery target over the past decade. Excitingly, a selective AP-1 inhibitor T-5224 (51) has been investigated in phase II human clinical trials. Nevertheless, no effective AP-1 inhibitors have yet been approved for clinical use. Despite significant advances achieved in understanding AP-1 biology and function, as well as the identification of small molecules modulating AP-1 associated signaling pathways, medicinal chemistry efforts remain an urgent need to yield selective and efficacious AP-1 inhibitors as a viable therapeutic strategy for human diseases.

  3. Tead and AP1 coordinate transcription and motility

    PubMed Central

    Liu, Xiangfan; Li, Huapeng; Rajurkar, Mihir; Li, Qi; Cotton, Jennifer L.; Ou, Jianhong; Zhu, Lihua J.; Goel, Hira L.; Mercurio, Arthur M.; Park, Joo-Seop; Davis, Roger J.; Mao, Junhao

    2016-01-01

    SUMMARY The Tead family transcription factors are the major intracellular mediators of the Hippo-Yap pathway. Despite the importance of Hippo signaling in tumorigenesis, Tead-dependent downstream oncogenic programs and target genes in cancer cells remain poorly understood. Here we characterize Tead4-mediated transcriptional networks in a diverse range of cancer cells, including neuroblastoma, colorectal, lung, and endometrial carcinomas. By intersecting genome-wide chromatin occupancy analyses of Tead4, JunD and Fra1/2, we find that Tead4 cooperates with AP1 transcription factors to coordinate target gene transcription. We find that Tead-AP1 interaction is JNK independent, but engages the SRC1-3 coactivators to promote downstream transcription. Furthermore we show that Tead-AP1 cooperation regulates the activity of the Dock-Rac/CDC42 module and drives the expression of a unique core set of target genes, thereby directing cell migration and invasion. Together, our data unveil a critical regulatory mechanism underlying Tead- and AP1-controlled transcriptional and functional outputs in cancer cells. PMID:26832411

  4. Bovine dialyzable leukocyte extract modulates AP-1 DNA-binding activity and nuclear transcription factor expression in MCF-7 breast cancer cells.

    PubMed

    Mendoza-Gamboa, E; Franco-Molina, M A; Zapata-Benavides, P; Castillo-Tello, P; Vera-García, M E; Tamez-Guerra, R S; Rodríguez-Padilla, C

    2008-01-01

    We have previously demonstrated that bovine dialyzable leukocyte extract (bDLE) induces death through an apoptosis mechanism in MCF-7 breast cancer cells. Depending on the cell type and stimulus, activating protein-1 (AP-1) has been shown to regulate cell proliferation and differentiation, the stress response, apoptosis and survival. It remains unknown whether AP-1 and other transcription factors are mechanisms by which bDLE induces cell death. To determine whether bDLE modulates the AP-1 DNA binding and gene expression, MCF-7 breast cancer cells were treated with bDLE (0, 1, 5, 10 U) for 72 h and evaluated by electrophoretic mobility shift assay, reverse transcriptase-polymerase chain reaction and Western blot assays. bDLE induced inhibition of cell growth, suppressed the AP-1 DNA-binding activity, decreased c-Jun protein expression and modulated NFATx, NFATc, NFkappaB, c-Jun and c-Fos transcription factor gene expression in MCF-7 breast cancer cells. The present data indicate that bDLE can block the AP-1 DNA-binding activity and expression of several transcriptions factors in breast cancer cells, which will have great potential in improving cancer therapy.

  5. Megakaryocytic Maturation in Response to Shear Flow Is Mediated by the Activator Protein 1 (AP-1) Transcription Factor via Mitogen-activated Protein Kinase (MAPK) Mechanotransduction.

    PubMed

    Luff, Stephanie A; Papoutsakis, Eleftherios T

    2016-04-08

    Megakaryocytes (MKs) are exposed to shear flow as they migrate from the bone marrow hematopoietic compartment into circulation to release pro/preplatelets into circulating blood. Shear forces promote DNA synthesis, polyploidization, and maturation in MKs, and platelet biogenesis. To investigate mechanisms underlying these MK responses to shear, we carried out transcriptional analysis on immature and mature stem cell-derived MKs exposed to physiological shear. In immature (day (d)9) MKs, shear exposure up-regulated genes related to growth and MK maturation, whereas in mature (d12) MKs, it up-regulated genes involved in apoptosis and intracellular transport. Following shear-flow exposure, six activator protein 1 (AP-1) transcripts (ATF4,JUNB,JUN,FOSB,FOS, andJUND) were up-regulated at d9 and two AP-1 proteins (JunD and c-Fos) were up-regulated both at d9 and d12. We show that mitogen-activated protein kinase (MAPK) signaling is linked to both the shear stress response and AP-1 up-regulation. c-Jun N-terminal kinase (JNK) phosphorylation increased significantly following shear stimulation, whereas JNK inhibition reduced shear-induced JunD expression. Although p38 phosphorylation did not increase following shear flow, its inhibition reduced shear-induced JunD and c-Fos expression. JNK inhibition reduced fibrinogen binding and P-selectin expression of d12 platelet-like particles (PLPs), whereas p38 inhibition reduced fibrinogen binding of d12 PLPs. AP-1 expression correlated with increased MK DNA synthesis and polyploidization, which might explain the observed impact of shear on MKs. To summarize, we show that MK exposure to shear forces results in JNK activation, AP-1 up-regulation, and downstream transcriptional changes that promote maturation of immature MKs and platelet biogenesis in mature MKs.

  6. Ultraviolet irradiation induces CYR61/CCN1, a mediator of collagen homeostasis, through activation of transcription factor AP-1 in human skin fibroblasts.

    PubMed

    Quan, Taihao; Qin, Zhaoping; Xu, Yiru; He, Tianyuan; Kang, Sewon; Voorhees, John J; Fisher, Gary J

    2010-06-01

    UV irradiation from the sun elevates the production of collagen-degrading matrix metalloproteinases (MMPs) and reduces the production of new collagen. This imbalance of collagen homeostasis impairs the structure and function of the dermal collagenous extracellular matrix (ECM), thereby promoting premature skin aging (photoaging). We report here that aberrant dermal collagen homeostasis in UV-irradiated human skin is mediated in part by a CCN-family member, cysteine-rich protein-61 (CYR61/CCN1). CYR61 is significantly elevated in acutely UV-irradiated human skin in vivo, and UV-irradiated human skin fibroblasts. Knockdown of CYR61 significantly attenuates UV irradiation-induced inhibition of type-I procollagen and upregulation of MMP-1. Determination of CYR61 mRNA and protein indicates that the primary mechanism of CYR61 induction by UV irradiation is transcriptional. Analysis of CYR61 proximal promoter showed that a sequence conforming to the consensus binding site for transcription factor activator protein-1 (AP-1) is required for promoter activity. UV irradiation increased the binding of AP-1-family members c-Jun and c-Fos to this AP-1 site. Furthermore, functional blockade of c-Jun or knockdown of c-Jun significantly reduced the UV irradiation-induced activation of CYR61 promoter and CYR61 gene expression. These data show that CYR61 is transcriptionally regulated by UV irradiation through transcription factor AP-1, and mediates altered collagen homeostasis that occurs in response to UV irradiation in human skin fibroblasts.

  7. Ets domain transcription factor PE1 suppresses human interstitial collagenase promoter activity by antagonizing protein-DNA interactions at a critical AP1 element.

    PubMed

    Bidder, M; Loewy, A P; Latifi, T; Newberry, E P; Ferguson, G; Willis, D M; Towler, D A

    2000-08-01

    In MC3T3E1 calvarial osteoblasts, fibroblast growth factor receptor (FGFR) signaling elicits multiple transcriptional responses, including upregulation of the interstitial collagenase/matrix metalloproteinase 1 (MMP1) promoter. FGF responsiveness maps to a bipartite Ets/AP1 element at base pairs -123 to -61 in the human MMP1 promoter. Under basal conditions, the MMP1 promoter is repressed in part via protein-DNA interactions at the Ets cognate, and minimally two mechanisms convey MMP1 promoter upregulation by FGF2: (a) transcriptional activation via Fra1/c-Jun containing DNA-protein interactions at the AP1 cognate and (b) derepression of promoter activity regulated by the Ets cognate. To identify osteoblast Ets repressors that potentially participate in gene expression in the osteoblast, we performed reverse transcription-polymerase chain reaction (RT-PCR) analysis of mRNA isolated from MC3T3E1 cells, using degenerative amplimers to the conserved Ets DNA binding domain to survey the Ets genes expressed by these cells. Six distinct Ets mRNAs were identified: Ets2, Fli1, GABPalpha, SAP1, Elk1, and PE1. Of these, only PE1 has extensive homology to the known Ras-regulated Ets transcriptional repressor, ERF. Therefore, we cloned and characterized PE1 cDNA from a mouse brain library and performed functional analysis of this particular Ets family member. A 2 kb transcript was isolated from brain that encodes a approximately 57 kDa protein; the predicted protein contains the known N-terminal Ets domain of PE1 and a novel C-terminal domain with signficant homology to murine ERF. The murine PE1 open reading frame (ORF) is much larger than the previously reported human PE1 ORF. Consistent with this, affinity-purified rabbit anti-mouse PE1 antibody specifically recognizes an approximately 66 kDa protein present only in the nuclear fraction of MC3T3E1 osteoblasts. Recombinant PE1 binds authentic AGGAWG Ets DNA cognates, and transient transfection studies demonstrate that PE1

  8. Activation of AP-1 Transcription Factors Differentiates FGF2 and Vascular Endothelial Growth Factor Regulation of Endothelial Nitric-oxide Synthase Expression in Placental Artery Endothelial Cells*

    PubMed Central

    Mata-Greenwood, Eugenia; Liao, Wu-xiang; Wang, Wen; Zheng, Jing; Chen, Dong-bao

    2010-01-01

    FGF2 (fibroblast growth factor 2), but not vascular endothelial growth factor (VEGF), stimulates sustained activation of ERK2/1 for endothelial NOS3 (nitric-oxide synthase 3) protein expression in ovine fetoplacental artery endothelial cells (oFPAEC). We deciphered herein the downstream signaling of ERK2/1 responsible for NOS3 expression by FGF2 in oFPAEC. FGF2, but not VEGF, increased NOS3 mRNA levels without altering its degradation. FGF2, but not VEGF, trans-activated sheep NOS3 promoter, and this was dependent on ERK2/1 activation. FGF2 did not trans-activate NOS3 promoters with deletions upstream of the consensus AP-1 site (TGAGTC A, −678 to −685). Trans-activation of wild-type NOS3 promoter by FGF2 was significantly inhibited when either the AP-1 or the cAMP-response element (CRE)-like sequence (TGCGTCA, −752 to −758) was mutated and was completely blocked when both were mutated. EMSA analyses showed that FGF2, but not VEGF, stimulated AP-1 and CRE DNA-protein complexes primarily composed of JunB and Fra1. Chromatin immunoprecipitation assays confirmed JunB/Fra1 binding to NOS3 promoter AP-1 and CRE elements in intact cells. FGF2, but not VEGF, stimulated JunB and Fra1 expressions; all preceded NOS3 up-regulation and were inhibited by PD98059. Down-regulation of JunB or Fra-1, but not c-Jun, blocked FGF2 stimulation of NOS3 expression and NO production. AP-1 inhibition suppressed FGF2 stimulation of NOS3 expression in human umbilical vein EC and uterine artery endothelial cells. Thus, FGF2 induction of NOS3 expression is mainly mediated by AP-1-dependent transcription involving JunB and Fra1 up-regulation via sustained ERK2/1 activation in endothelial cells. PMID:20371606

  9. Berberine modulates AP-1 activity to suppress HPV transcription and downstream signaling to induce growth arrest and apoptosis in cervical cancer cells

    PubMed Central

    2011-01-01

    Background- Specific types of high risk Human papillomaviruses (HR-HPVs) particularly, HPV types 16 and 18 cause cervical cancer and while the two recently developed vaccines against these HPV types are prophylactic in nature, therapeutic options for treatment and management of already existing HPV infection are not available as yet. Because transcription factor, Activator Protein-1 (AP-1) plays a central role in HPV-mediated cervical carcinogenesis, we explored the possibility of its therapeutic targeting by berberine, a natural alkaloid derived from a medicinal plant species, Berberis which has been shown to possess anti-inflammatory and anti-cancer properties with no known toxicity; however, the effect of berberine against HPV has not been elucidated. Results- We studied the effect of berberine on HPV16-positive cervical cancer cell line, SiHa and HPV18-positive cervical cancer cell line, HeLa using electrophoretic mobility gel shift assays, western and northern blotting which showed that berberine could selectively inhibit constitutively activated AP-1 in a dose- and time-dependent manner and downregulates HPV oncogenes expression. Inhibition of AP-1 was also accompanied by changes in the composition of their DNA-binding complex. Berberine specifically downregulated expression of oncogenic c-Fos which was also absent in the AP-1 binding complex. Treatment with berberine resulted in repression of E6 and E7 levels and concomitant increase in p53 and Rb expression in both cell types. Berberine also suppressed expression of telomerase protein, hTERT, which translated into growth inhibition of cervical cancer cells. Interestingly, a higher concentration of berberine was found to reduce the cell viability through mitochondria-mediated pathway and induce apoptosis by activating caspase-3. Conclusion- These results indicate that berberine can effectively target both the host and viral factors responsible for development of cervical cancer through inhibition of AP-1 and

  10. Tamoxifen increases nuclear respiratory factor 1 transcription by activating estrogen receptor beta and AP-1 recruitment to adjacent promoter binding sites.

    PubMed

    Ivanova, Margarita M; Luken, Kristen H; Zimmer, Amber S; Lenzo, Felicia L; Smith, Ryan J; Arteel, Maia W; Kollenberg, Tara J; Mattingly, Kathleen A; Klinge, Carolyn M

    2011-04-01

    Little is known about endogenous estrogen receptor β (ERβ) gene targets in human breast cancer. We reported that estradiol (E(2)) induces nuclear respiratory factor-1 (NRF-1) transcription through ERα in MCF-7 breast cancer cells. Here we report that 4-hydroxytamoxifen (4-OHT), with an EC(50) of ~1.7 nM, increases NRF-1 expression by recruiting ERβ, cJun, cFos, CBP, and RNA polymerase II to and dismissing NCoR from the NRF1 promoter. Promoter deletion and transient transfection studies showed that the estrogen response element (ERE) is essential and that an adjacent AP-1 site contributes to maximal 4-OHT-induced NRF-1 transcription. siRNA knockdown of ERβ revealed that ERβ inhibits basal NRF-1 expression and is required for 4-OHT-induced NRF-1 transcription. An AP-1 inhibitor blocked 4-OHT-induced NRF-1 expression. The 4-OHT-induced increase in NRF-1 resulted in increased transcription of NRF-1 target CAPNS1 but not CYC1, CYC2, or TFAM despite increased NRF-1 coactivator PGC-1α protein. The absence of TFAM induction corresponds to a lack of Akt-dependent phosphorylation of NRF-1 with 4-OHT treatment. Overexpression of NRF-1 inhibited 4-OHT-induced apoptosis and siRNA knockdown of NRF-1 increased apoptosis, indicating an antiapoptotic role for NRF-1. Overall, NRF-1 expression and activity is regulated by 4-OHT via endogenous ERβ in MCF-7 cells.

  11. STP-A11, an oncoprotein of Herpesvirus saimiri augments both NF-kappaB and AP-1 transcription activity through TRAF6.

    PubMed

    Jeong, Sunam; Cho, Il-Rae; An, Won Gun; Jhun, Byung Hak; Lee, BokSoo; Park, Keerang; Chung, Young-Hwa

    2007-02-28

    Herpesvirus saimiri (HVS), a member of the gamma-herpesvirus family, encodes an oncoprotein called Saimiri Transforming Protein (STP) which is required for lymphoma induction in non-human primates. However, a detailed mechanism of STP-A11-induced oncogenesis has not been revealed yet. We first report that STP-A11 oncoprotein interacts with TNF-alpha receptor-associated factor (TRAF) 6 in vivo and in vitro. Mutagenesis analysis of the TRAF6-binding motif (10)PQENDE(15) in STP-A11 reveals that Glu (E)(12) residue is critical for binding to TRAF6 and NF-kappaB activation. Interestingly, co-expression of E12A mutant, lack of TRAF6 binding, with cellular Src (Src) results in decreased transcriptional activity of Stat3 and AP-1, a novel target of STP-A11 compared to that of wild type. Furthermore, the presence of STP-A11 enhances the association of TRAF6 with Src and induces the translocation of both TRAF6 and Src to a nonionic detergent-insoluble fraction. Taken together, these studies suggest that STP-A11 oncoprotein up-regulates both NF-kappaB and AP-1 transcription activity through TRAF6, which would ultimately contribute cellular transformation.

  12. Terminalia catappa Exerts Antimetastatic Effects on Hepatocellular Carcinoma through Transcriptional Inhibition of Matrix Metalloproteinase-9 by Modulating NF-κB and AP-1 Activity.

    PubMed

    Yeh, Chao-Bin; Hsieh, Ming-Ju; Hsieh, Yih-Shou; Chien, Ming-Hsien; Lin, Pen-Yuan; Chiou, Hui-Ling; Yang, Shun-Fa

    2012-01-01

    High mortality and morbidity rates for hepatocellular carcinoma (HCC) in Taiwan primarily result from uncontrolled tumor metastasis. Previous studies have identified that Terminalia catappa leaf extracts (TCE) exert hepatoprotective, antioxidative, antiinflammatory, anticancer, and antimetastatic activities. However, the effects of TCE on HCC and the underlying molecular mechanisms of its activities have yet to be fully elucidated. The present study's findings demonstrate that TCE concentration dependently inhibits human HCC migration/invasion. Zymographic and western blot analyses revealed that TCE inhibited the activities and expression of matrix metalloproteinase-9 (MMP-9). Assessment of mRNA levels, using reverse transcriptase polymerase chain reaction (PCR) and real-time PCR, and promoter assays confirmed the inhibitory effects of TCE on MMP-9 expression in HCC cells. The inhibitory effects of TCE on MMP-9 proceeded by upregulating tissue inhibitor of metalloproteinase-1 (TIMP-1), as well as suppressing nuclear translocation and DNA binding activity of nuclear factor-kappa B (NF-κB) and activating protein-1 (AP-1) on the MMP-9 promoter in Huh7 cells. In conclusion, TCE inhibits MMP-9 expression and HCC cell metastasis and, thus, has potential use as a chemopreventive agent. Its inhibitory effects are associated with downregulation of the binding activities of the transcription factors NF-κB and AP-1.

  13. Modulation of AP-1 activity by nitric oxide (NO) in vitro: NO-mediated modulation of AP-1.

    PubMed

    Tabuchi, A; Sano, K; Oh, E; Tsuchiya, T; Tsuda, M

    1994-08-29

    To understand the role of nitric oxide (NO) in controlling the specific DNA-binding activities of transcriptional factors, we investigated the in vitro effect of the NO-donor sodium nitroprusside (SNP) on the AP-1 activity of cultured mouse cerebellar granule cells. A gel-mobility assay showed that SNP inhibited AP-1 activity in the presence, but not the absence of dithiothreitol (DTT). This DTT-dependent inhibition of AP-1 activity by SNP corresponded with the activation of the chemical reactivity of SNP with DTT, which can be monitored by the production of nitrite (NO2-). In contrast, diamide, a typical sulfhydryl oxidizing agent, inhibited AP-1 activity in the absence of DTT and its inhibitory effect was reversed competitively by DTT. Studies using structurally or functionally related analogues of SNP demonstrated that S-nitrosylation of the AP-1 moiety mediated by some NO-carriers but not by free NO, which can be produced by the chemical reaction of SNP with DTT, was responsible for the inhibition of AP-1 activity, suggesting NO-mediated regulation of the AP-1 transcriptional factor.

  14. Sp1 binds two sites in the CD11c promoter in vivo specifically in myeloid cells and cooperates with AP1 to activate transcription.

    PubMed Central

    Noti, J D; Reinemann, B C; Petrus, M N

    1996-01-01

    The leukocyte integrin gene, CD11c, is transcriptionally regulated and is expressed predominantly on differentiated cells of the myelomonocytic lineage. In this study we have demonstrated that the regions -72 to -63 and -132 to -104 of the CD11c promoter contain elements responsible for phorbol ester-induced differentiation of the myeloid cell line HL60. DNase I footprinting analysis revealed that these regions can bind purified Sp1, and supershift analysis with Sp1 antibody confirmed that Sp1 in HL60 nuclear extracts could bind these regions. Transfection analysis of CD11c promoter-chloramphenicol acetyltransferase constructs containing deletions of these Sp1-binding sites revealed that these sites are essential for expression of the CD11c gene in HL60 cells but not in the T-cell line Molt4 or the cervical carcinoma cell line HeLa. Moreover, cotransfection of pPacSp1 along with these CD11c promoter-chloramphenicol acetyltransferase constructs into Sp1-deficient Drosophila Schneider 2 cells verified that these sites are essential for Sp1-dependent expression of the CD11c promoter. In vivo genomic footprinting revealed that Sp1 contacts the CD11c promoter within the regions -69 to -63 and -116 to -105 in phorbol 12-myristate 13-acetate-differentiated HL60 cells but not in undifferentiated HL60 cells or in Molt4 or HeLa cells. Cotransfection assays in HL60 cells revealed that Sp1 acts synergistically with Ap1 to activate CD11c. Further, both Sp1 sites are capable of cooperating with AP1. In vitro DNase I footprinting analysis with purified Sp1 and c-jun proteins showed that Sp1 binding could facilitate binding of c-jun. We propose that myeloid-specific expression of the CD11c promoter and is facilitated by cooperative interaction between the Sp1- and Ap1-binding sites. PMID:8649405

  15. Transient receptor potential melastatin-3 (TRPM3)-induced activation of AP-1 requires Ca2+ ions and the transcription factors c-Jun, ATF2, and ternary complex factor.

    PubMed

    Lesch, Andrea; Hui, Xin; Lipp, Peter; Thiel, Gerald

    2015-04-01

    The steroid pregnenolone sulfate activates the transcription factor activator protein-1 (AP-1) via stimulation of transient receptor potential melastatin-3 (TRPM3) channels. Here, we show that the signaling pathway requires an influx of Ca(2+) ions into the cells and a rise in the intracellular Ca(2+) levels. The upregulation of AP-1 was attenuated in cells that overexpressed mitogen activated protein kinase phosphatase-1, indicating that Ca(2+) ions prolong the signaling cascade via activation of mitogen activated protein kinases. On the transcriptional level, expression of a dominant-negative mutant of the basic region leucine zipper protein c-Jun, a major constituent of the AP-1 transcription factor complex, or expression of a c-Jun-specific short hairpin RNA attenuated pregnenolone sulfate-induced AP-1 activation. In addition, stimulation of TRPM3 channels increased the transcriptional activation potential of the basic region leucine zipper protein ATF2. Inhibition of ATF2 target gene expression via expression of a dominant-negative mutant of ATF2 or expression of an ATF2-specific short hairpin RNA interfered with TRPM3-mediated stimulation of AP-1. Moreover, we show that a dominant-negative mutant of the ternary complex factor (TCF) Elk-1 attenuated the upregulation of AP-1 following stimulation of TRPM3 channels. Thus, c-Jun, ATF2, and TCFs are required to connect the intracellular signaling cascade elicited by activation of TRPM3 channels with enhanced transcription of AP-1-regulated genes. We conclude that pregnenolone sulfate-induced TRPM3 channel activation changes the gene expression pattern of the cells by activating transcription of c-Jun-, ATF2-, and TCF-controlled genes.

  16. The Transcription Factor AP-1 Is Required for EGF-induced Activation of Rho-like GTPases, Cytoskeletal Rearrangements, Motility, and In Vitro Invasion of A431 Cells

    PubMed Central

    Malliri, Angeliki; Symons, Marc; Hennigan, Robert F.; Hurlstone, Adam F.L.; Lamb, Richard F.; Wheeler, Tricia; Ozanne, Bradford W.

    1998-01-01

    Human squamous cell carcinomas (SCC) frequently express elevated levels of epidermal growth factor receptor (EGFR). EGFR overexpression in SCC-derived cell lines correlates with their ability to invade in an in vitro invasion assay in response to EGF, whereas benign epidermal cells, which express low levels of EGFR, do not invade. EGF-induced invasion of SCC-derived A431 cells is inhibited by sustained expression of the dominant negative mutant of c-Jun, TAM67, suggesting a role for the transcription factor AP-1 (activator protein-1) in regulating invasion. Significantly, we establish that sustained TAM67 expression inhibits growth factor–induced cell motility and the reorganization of the cytoskeleton and cell-shape changes essential for this process: TAM67 expression inhibits EGF-induced membrane ruffling, lamellipodia formation, cortical actin polymerization and cell rounding. Introduction of a dominant negative mutant of Rac and of the Rho inhibitor C3 transferase into A431 cells indicates that EGF-induced membrane ruffling and lamellipodia formation are regulated by Rac, whereas EGF-induced cortical actin polymerization and cell rounding are controlled by Rho. Constitutively activated mutants of Rac or Rho introduced into A431 or A431 cells expressing TAM67 (TA cells) induce equivalent actin cytoskeletal rearrangements, suggesting that the effector pathways downstream of Rac and Rho required for these responses are unimpaired by sustained TAM67 expression. However, EGF-induced translocation of Rac to the cell membrane, which is associated with its activation, is defective in TA cells. Our data establish a novel link between AP-1 activity and EGFR activation of Rac and Rho, which in turn mediate the actin cytoskeletal rearrangements required for cell motility and invasion. PMID:9817764

  17. Transcription of the Transforming Growth Factor β Activating Integrin β8 Subunit Is Regulated by SP3, AP-1, and the p38 Pathway*

    PubMed Central

    Markovics, Jennifer A.; Araya, Jun; Cambier, Stephanie; Jablons, David; Hill, Arthur; Wolters, Paul J.; Nishimura, Stephen L.

    2010-01-01

    Integrin αvβ8 is a critical regulator of transforming growth factor β activation in vasculogenesis during development, immune regulation, and endothelial/epithelial-mesenchymal homeostasis. Recent studies have suggested roles for integrin β8 in the pathogenesis of chronic obstructive pulmonary disease, brain arteriovenous malformations, and select cancers (Araya, J., Cambier, S., Markovics, J. A., Wolters, P., Jablons, D., Hill, A., Finkbeiner, W., Jones, K., Broaddus, V. C., Sheppard, D., Barzcak, A., Xiao, Y., Erle, D. J., and Nishimura, S. L. (2007) J. Clin. Invest. 117, 3551–3562; Su, H., Kim, H., Pawlikowska, L., Kitamura, H., Shen, F., Cambier, S., Markovics, J., Lawton, M. T., Sidney, S., Bollen, A. W., Kwok, P. Y., Reichardt, L., Young, W. L., Yang, G. Y., and Nishimura, S. L. (2010) Am. J. Pathol. 176, 1018–1027; Culhane, A. C., and Quackenbush, J. (2009) Cancer Res. 69, 7480–7485; Cambier, S., Mu, D. Z., O'Connell, D., Boylen, K., Travis, W., Liu, W. H., Broaddus, V. C., and Nishimura, S. L. (2000) Cancer Res. 60, 7084–7093). Here we report the first identification and characterization of the promoter for ITGB8. We show that a SP binding site and a cyclic AMP response element (CRE) in the ITGB8 core promoter are required for its expression and that Sp1, Sp3, and several AP-1 transcription factors form a complex that binds to these sites in a p38-dependent manner. Furthermore, we demonstrate the requirement for Sp3, ATF-2, and p38 for the transcription and protein expression of integrin β8. Additionally, reduction of SP3 or inhibition of p38 blocks αvβ8-mediated transforming growth factor β activation. These results place integrin β8 expression and activity under the control of ubiquitous transcription factors in a stress-activated and pro-inflammatory pathway. PMID:20519498

  18. Tiron Inhibits UVB-Induced AP-1 Binding Sites Transcriptional Activation on MMP-1 and MMP-3 Promoters by MAPK Signaling Pathway in Human Dermal Fibroblasts

    PubMed Central

    Zhang, Chao; Zhao, Mei; Zhang, Quan-Wu; Gao, Feng-Hou

    2016-01-01

    Recent research found that Tiron was an effective antioxidant that could act as the intracellular reactive oxygen species (ROS) scavenger or alleviate the acute toxic metal overload in vivo. In this study, we investigated the inhibitory effect of Tiron on matrix metalloproteinase (MMP)-1 and MMP-3 expression in human dermal fibroblast cells. Western blot and ELISA analysis revealed that Tiron inhibited ultraviolet B (UVB)-induced protein expression of MMP-1 and MMP-3. Real-time quantitative PCR confirmed that Tiron could inhibit UVB-induced mRNA expression of MMP-1 and MMP-3. Furthermore, Tiron significantly blocked UVB-induced activation of the MAPK signaling pathway and activator protein (AP)-1 in the downstream of this transduction pathway in fibroblasts. Through the AP-1 binding site mutation, it was found that Tiron could inhibit AP-1-induced upregulation of MMP-1 and MMP-3 expression through blocking AP-1 binding to the AP-1 binding sites in the MMP-1 and MMP-3 promoter region. In conclusion, Tiron may be a novel antioxidant for preventing and treating skin photoaging UV-induced. PMID:27486852

  19. The human papillomavirus type 16 E7 gene product interacts with and trans-activates the AP1 family of transcription factors.

    PubMed Central

    Antinore, M J; Birrer, M J; Patel, D; Nader, L; McCance, D J

    1996-01-01

    The E7 gene product of human papillomavirus type 16 (HPV16) binds to the retinoblastoma gene product (pRb) and dissociates pRb-E2F complexes. However, the observation that the ability of E7 to bind pRb is not required for the HPV16-induced immortalization of primary keratinocytes prompted a search for other cellular factors bound by E7. Using a glutathione-S-transferase (GST) fusion protein system, we show that E7 complexes with AP1 transcription factors including c-Jun, JunB, JunD and c-Fos. The ability of E7 to complex with c-Jun in vivo is demonstrated by co-immunoprecipitation and the yeast two-hybrid system. An analysis of E7 point mutants in the GST system indicates that the E7 zinc-finger motif, but not the pRb binding domain, is involved in these interactions. Using c-Jun deletion mutants, E7 binding maps between amino acids 224 and 286 of c-Jun. E7 trans-activates c-Jun-induced transcription from a Jun responsive promoter, and this activity correlates with the ability of E7 mutants to bind Jun proteins. Finally, a transcriptionally inactive c-Jun deletion, which can bind E7, interferes with the E7-induced transformation of rat embryo fibroblasts in cooperation with an activated ras, indicating that the Jun-E7 interaction is physiologically relevant and that Jun factors may be targeted in the E7 transformation pathway. Images PMID:8617242

  20. CD43-mediated signals induce DNA binding activity of AP-1, NF-AT, and NFkappa B transcription factors in human T lymphocytes.

    PubMed

    Santana, M A; Pedraza-Alva, G; Olivares-Zavaleta, N; Madrid-Marina, V; Horejsi, V; Burakoff, S J; Rosenstein, Y

    2000-10-06

    Although numerous reports document a role for CD43 in T cell signaling, the direct participation of this molecule in cell activation has been questioned. In this study we show that CD43 ligation on human normal peripheral T cells was sufficient to induce interleukin-2, CD69, and CD40-L gene expression, without requiring signals provided by additional receptor molecules. This response was partially inhibited by cyclosporin A and staurosporine, suggesting the participation of both the Ca(2+) and the protein kinase C pathways in CD43 signaling. Consistent with the transient CD43-dependent intracellular Ca(2+) peaks reported by others, signals generated through the CD43 molecule resulted in the induction of NF-AT DNA binding activity. CD43-dependent signals resulted also in AP-1 and NFkappaB activation, probably as a result of protein kinase C involvement. AP-1 complexes bound to the AP-1 sequence contained c-Jun, and those bound to the NF-AT-AP-1 composite site contained c-Jun and Fos. NFkappaB complexes containing p65 could be found as early as 1 h after CD43 cross-linking, suggesting that CD43 participates in early events of T cell activation. The induction of the interleukin-2, CD69, and CD-40L genes and the participation of AP-1, NF-AT, and NFkappaB in the CD43-mediated signaling cascade implicate an important role for this molecule in the regulation of gene expression and cell function.

  1. Estrogen Induces c-myc Gene Expression via an Upstream Enhancer Activated by the Estrogen Receptor and the AP-1 Transcription Factor

    PubMed Central

    Wang, Chunyu; Mayer, Julie Ann; Mazumdar, Abhijit; Fertuck, Kirsten; Kim, Heetae; Brown, Myles

    2011-01-01

    c-myc oncogene is implicated in tumorigenesis of many cancers, including breast cancer. Although c-myc is a well-known estrogen-induced gene, its promoter has no estrogen-response element, and the underlying mechanism by which estrogen induces its expression remains obscure. Recent genome-wide studies by us and others suggested that distant elements may mediate estrogen induction of gene expression. In this study, we investigated the molecular mechanism by which estrogen induces c-myc expression with a focus on these distal elements. Estrogen rapidly induced c-myc expression in estrogen receptor (ER)-positive breast cancer cells. Although estrogen had little effect on c-myc proximal promoter activity, it did stimulate the activity of a luciferase reporter containing a distal 67-kb enhancer. Estrogen induction of this luciferase reporter was dependent upon both a half-estrogen response element and an activator protein 1 (AP-1) site within this enhancer, which are conserved across 11 different mammalian species. Small interfering RNA experiments and chromatin immunoprecipitation assays demonstrated the necessity of ER and AP-1 cross talk for estrogen to induce c-myc expression. TAM67, the AP-1 dominant negative, partially inhibited estrogen induction of c-myc expression and suppressed estrogen-induced cell cycle progression. Together, these results demonstrate a novel pathway of estrogen regulation of gene expression by cooperation between ER and AP-1 at the distal enhancer element and that AP-1 is involved in estrogen induction of the c-myc oncogene. These results solve the long-standing question in the field of endocrinology of how estrogen induces c-myc expression. PMID:21835891

  2. Transcriptional regulation of human novel gene SPATA12 promoter by AP-1 and HSF.

    PubMed

    Li, Dan; Lin, Yiting; Liu, Zhiwen; Zhang, Yunsheng; Rong, Zhuoxian; Liu, Xuanming

    2012-12-10

    Human SPATA12 is a spermatogenesis associated gene and is supposed to function as an inhibitor during male germ cell development. SPATA12 is specifically expressed in spermatocytes, spermatids, and spermatozoa of human testis. In order to understand the regulation mechanism of SPATA12 gene expression, we identified and characterized the SPATA12 gene core promoter region and transcription factor binding sites by using reporter gene assays. AP-1 is founded to be a potential transcriptional activator of SPATA12. The promoter activity of SPATA12 was drastically declined after AP-1 binding site mutation or deletion. We also demonstrated that AP-1 combined with Smad3/4 contributes to the transcriptional regulation of SPATA12 in response to TGF-β1. The expression of SPATA12 could be induced by TGF-β1 in a dose-dependent manner, suggesting that AP-1 as an activator plays a role in the regulation of SPATA12 promoter. We have also shown that heat shock treatment could activate the expression of SPATA12 and transcription factor HSF binding sites in the SPATA12 promoter might be responsible for this heat-induction. These results suggested that AP-1 and HSF may play an important role in regulating SPATA12 promoter activity.

  3. Modulation of activator protein-1 (AP-1) transcription factor and protein kinase C by hydrogen peroxide and D-alpha-tocopherol in vascular smooth muscle cells.

    PubMed

    Stäuble, B; Boscoboinik, D; Tasinato, A; Azzi, A

    1994-12-01

    The effects of hydrogen peroxide D-alpha-tocopherol and of D-beta-tocopherol on proliferation, protein kinase C and activator protein-1 (AP-1) activation have been studied in vascular smooth muscle cells. Cell proliferation, when activated by foetal calf serum, was inhibited by D-alpha-tocopherol. Protein kinase C activity was stimulated by hydrogen peroxide in a manner similar to phorbol myristate acetate; in the latter case, but not in the former, D-alpha-tocopherol inhibited the reaction. Hydrogen peroxide prevented phorbol-myristate-acetate-stimulated AP-1 binding to DNA but stimulated it if protein kinase C was down-regulated or inhibited. D-alpha-Tocopherol promoted AP-1 activation in quiescent cells but prevented its activation by phorbol myristate acetate. None of the described effects of D-alpha-tocopherol were shared by D-beta-tocopherol, suggesting a non-antioxidant mechanism as the basis of its action. The data show that hydrogen peroxide and D-alpha-tocopherol affect more than one element in the cell signal-transduction cascade.

  4. Normal dendrite growth in Drosophila motor neurons requires the AP-1 transcription factor.

    PubMed

    Hartwig, Cortnie L; Worrell, Jason; Levine, Richard B; Ramaswami, Mani; Sanyal, Subhabrata

    2008-09-01

    During learning and memory formation, information flow through networks is regulated significantly through structural alterations in neurons. Dendrites, sites of signal integration, are key targets of activity-mediated modifications. Although local mechanisms of dendritic growth ensure synapse-specific changes, global mechanisms linking neural activity to nuclear gene expression may have profound influences on neural function. Fos, being an immediate-early gene, is ideally suited to be an initial transducer of neural activity, but a precise role for the AP-1 transcription factor in dendrite growth remains to be elucidated. Here we measure changes in the dendritic fields of identified Drosophila motor neurons in vivo and in primary culture to investigate the role of the immediate-early transcription factor AP-1 in regulating endogenous and activity-induced dendrite growth. Our data indicate that (a) increased neural excitability or depolarization stimulates dendrite growth, (b) AP-1 (a Fos, Jun hetero-dimer) is required for normal motor neuron dendritic growth during development and in response to activity induction, and (c) neuronal Fos protein levels are rapidly but transiently induced in motor neurons following neural activity. Taken together, these results show that AP-1 mediated transcription is important for dendrite growth, and that neural activity influences global dendritic growth through a gene-expression dependent mechanism gated by AP-1.

  5. RAS/ERK pathway transcriptional regulation through ETS/AP-1 binding sites.

    PubMed

    Hollenhorst, Peter C

    2012-01-01

    The RAS/RAF/MEK/ERK signaling pathway is activated by mutation in many cancers. Neighboring ETS and AP-1 DNA binding sequences can act as response elements for transcriptional activation by this pathway. ERK phosphorylation of an ETS transcription factor is one mechanism of activating the RAS/ERK gene expression program that can promote cancer cell phenotypes such as proliferation, invasion, and metastasis. Recent genome-wide mapping of ETS proteins over-expressed by chromosomal rearrangement in prostate cancer reveals a second mechanism for activation of this gene expression program. An oncogenic subset of ETS transcription factors can activate RAS/ERK target genes even in the absence of RAS/ERK pathway activation by binding ETS/AP-1 sequences. Thus, regulation of cancer cell invasion and metastasis via ETS/AP-1 sequence elements depends on which ETS protein is bound, and the status of the RAS/ERK pathway. This commentary will focus on what is known about the selectivity of ETS/AP-1 sequences for different ETS transcription factors and the transcriptional consequences of ETS protein selection.

  6. Retinoic acid receptors inhibit AP1 activation by regulating extracellular signal-regulated kinase and CBP recruitment to an AP1-responsive promoter.

    PubMed

    Benkoussa, Madjid; Brand, Céline; Delmotte, Marie-Hélène; Formstecher, Pierre; Lefebvre, Philippe

    2002-07-01

    Retinoids exhibit antineoplastic activities that may be linked to retinoid receptor-mediated transrepression of activating protein 1 (AP1), a heterodimeric transcription factor composed of fos- and jun-related proteins. Here we show that transcriptional activation of an AP1-regulated gene through the mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase (ERK) pathway (MAPK(ERK)) is characterized, in intact cells, by a switch from a fra2-junD dimer to a junD-fosB dimer loading on its promoter and by simultaneous recruitment of ERKs, CREB-binding protein (CBP), and RNA polymerase II. All-trans-retinoic acid (atRA) receptor (RAR) was tethered constitutively to the AP1 promoter. AP1 transrepression by retinoic acid was concomitant to glycogen synthase kinase 3 activation, negative regulation of junD hyperphosphorylation, and to decreased RNA polymerase II recruitment. Under these conditions, fra1 loading to the AP1 response element was strongly increased. Importantly, CBP and ERKs were excluded from the promoter in the presence of atRA. AP1 transrepression by retinoids was RAR and ligand dependent, but none of the functions required for RAR-mediated transactivation was necessary for AP1 transrepression. These results indicate that transrepressive effects of retinoids are mediated through a mechanism unrelated to transcriptional activation, involving the RAR-dependent control of transcription factors and cofactor assembly on AP1-regulated promoters.

  7. Retinoic Acid Receptors Inhibit AP1 Activation by Regulating Extracellular Signal-Regulated Kinase and CBP Recruitment to an AP1-Responsive Promoter

    PubMed Central

    Benkoussa, Madjid; Brand, Céline; Delmotte, Marie-Hélène; Formstecher, Pierre; Lefebvre, Philippe

    2002-01-01

    Retinoids exhibit antineoplastic activities that may be linked to retinoid receptor-mediated transrepression of activating protein 1 (AP1), a heterodimeric transcription factor composed of fos- and jun-related proteins. Here we show that transcriptional activation of an AP1-regulated gene through the mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase (ERK) pathway (MAPKERK) is characterized, in intact cells, by a switch from a fra2-junD dimer to a junD-fosB dimer loading on its promoter and by simultaneous recruitment of ERKs, CREB-binding protein (CBP), and RNA polymerase II. All-trans-retinoic acid (atRA) receptor (RAR) was tethered constitutively to the AP1 promoter. AP1 transrepression by retinoic acid was concomitant to glycogen synthase kinase 3 activation, negative regulation of junD hyperphosphorylation, and to decreased RNA polymerase II recruitment. Under these conditions, fra1 loading to the AP1 response element was strongly increased. Importantly, CBP and ERKs were excluded from the promoter in the presence of atRA. AP1 transrepression by retinoids was RAR and ligand dependent, but none of the functions required for RAR-mediated transactivation was necessary for AP1 transrepression. These results indicate that transrepressive effects of retinoids are mediated through a mechanism unrelated to transcriptional activation, involving the RAR-dependent control of transcription factors and cofactor assembly on AP1-regulated promoters. PMID:12052862

  8. Mineralocorticoid Receptor (MR) trans-Activation of Inflammatory AP-1 Signaling: DEPENDENCE ON DNA SEQUENCE, MR CONFORMATION, AND AP-1 FAMILY MEMBER EXPRESSION.

    PubMed

    Dougherty, Edward J; Elinoff, Jason M; Ferreyra, Gabriela A; Hou, Angela; Cai, Rongman; Sun, Junfeng; Blaine, Kevin P; Wang, Shuibang; Danner, Robert L

    2016-11-04

    Glucocorticoids are commonly used to treat inflammatory disorders. The glucocorticoid receptor (GR) can tether to inflammatory transcription factor complexes, such as NFκB and AP-1, and trans-repress the transcription of cytokines, chemokines, and adhesion molecules. In contrast, aldosterone and the mineralocorticoid receptor (MR) primarily promote cardiovascular inflammation by incompletely understood mechanisms. Although MR has been shown to weakly repress NFκB, its role in modulating AP-1 has not been established. Here, the effects of GR and MR on NFκB and AP-1 signaling were directly compared using a variety of ligands, two different AP-1 consensus sequences, GR and MR DNA-binding domain mutants, and siRNA knockdown or overexpression of core AP-1 family members. Both GR and MR repressed an NFκB reporter without influencing p65 or p50 binding to DNA. Likewise, neither GR nor MR affected AP-1 binding, but repression or activation of AP-1 reporters occurred in a ligand-, AP-1 consensus sequence-, and AP-1 family member-specific manner. Notably, aldosterone interactions with both GR and MR demonstrated a potential to activate AP-1. DNA-binding domain mutations that eliminated the ability of GR and MR to cis-activate a hormone response element-driven reporter variably affected the strength and polarity of these responses. Importantly, MR modulation of NFκB and AP-1 signaling was consistent with a trans-mechanism, and AP-1 effects were confirmed for specific gene targets in primary human cells. Steroid nuclear receptor trans-effects on inflammatory signaling are context-dependent and influenced by nuclear receptor conformation, DNA sequence, and the expression of heterologous binding partners. Aldosterone activation of AP-1 may contribute to its proinflammatory effects in the vasculature.

  9. Arsenite suppression of involucrin transcription through AP1 promoter sites in cultured human keratinocytes

    SciTech Connect

    Sinitsyna, Nadezda N.; Reznikova, Tatiana V.; Qin Qin; Song, Hyukhwan; Phillips, Marjorie A.; Rice, Robert H.

    2010-03-15

    While preserving keratinocyte proliferative ability, arsenite suppresses cellular differentiation markers by preventing utilization of AP1 transcriptional response elements. In present experiments, arsenite had a dramatic effect in electrophoretic mobility supershift analysis of proteins binding to an involucrin promoter AP1 response element. Without arsenite treatment, binding of JunB and Fra1 was readily detected in nuclear extracts from preconfluent cultures and was not detected a week after confluence, while c-Fos was detected only after confluence. By contrast, band shift of nuclear extracts from arsenite treated cultures showed only JunB and Fra1 binding in postconfluent as well as preconfluent cultures. Immunoblotting of cell extracts showed that arsenite treatment prevented the loss of Fra1 and the increase in c-Fos proteins that occurred after confluence in untreated cultures. Chromatin immunoprecipitation assays demonstrated substantial reduction of c-Fos and acetylated histone H3 at the proximal and distal AP1 response elements in the involucrin promoter and of coactivator p300 at the proximal element. Alteration of AP1 transcription factors was also examined in response to treatment with four metal containing compounds (chromate, vanadate, hemin, divalent cadmium) that also suppress involucrin transcription. These agents all influenced transcription at AP1 elements in a transcriptional reporter assay, but exhibited less effect than arsenite on binding activity assessed by mobility shift and chromatin immunoprecipitation and displayed variable effects on AP1 protein levels. These findings help trace a mechanism by which transcriptional effects of arsenite become manifest and help rationalize the unique action of arsenite, compared to the other agents, to preserve proliferative ability.

  10. AP-1 Transcription Factors Mediate BDNF-Positive Feedback Loop in Cortical Neurons.

    PubMed

    Tuvikene, Jürgen; Pruunsild, Priit; Orav, Ester; Esvald, Eli-Eelika; Timmusk, Tõnis

    2016-01-27

    Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, regulates both survival and differentiation of several neuronal populations in the nervous system during development, as well as synaptic plasticity in the adult brain. BDNF exerts its biological functions through its receptor TrkB. Although the regulation of BDNF transcription by neuronal activity has been widely studied, little is known about TrkB signaling-dependent expression of BDNF. Using rat primary cortical neuron cultures, we show that the BDNF gene is a subject to an extensive autoregulatory loop, where TrkB signaling upregulates the expression of all major BDNF transcripts, mainly through activating MAPK pathways. Investigating the mechanisms behind this autoregulation, we found that AP-1 transcription factors, comprising Jun and Fos family members, participate in the induction of BDNF exon I, III, and VI transcripts. AP-1 transcription factors directly upregulate the expression of exon I transcripts by binding two novel AP-1 cis-elements in promoter I. Moreover, our results show that the effect of AP-1 proteins on the activity of rat BDNF promoters III and VI is indirect, because AP-1 proteins were not detected to bind the respective promoter regions by chromatin immunoprecipitation (ChIP). Collectively, we describe an extensive positive feedback system in BDNF regulation, adding a new layer to the elaborate control of BDNF gene expression. Here, we show for the first time that in rat primary cortical neurons the expression of all major BDNF transcripts (exon I, II, III, IV, VI, and IXa transcripts) is upregulated in response to TrkB signaling, and that AP-1 transcription factors participate in the induction of exon I, III, and VI transcripts. Moreover, we have described two novel functional AP-1 cis-elements in BDNF promoter I, responsible for the activation of the promoter in response to TrkB signaling. Our results indicate the existence of a positive feedback loop for

  11. AP-1 transcription factor mediates VEGF-induced endothelial cell migration and proliferation.

    PubMed

    Jia, Jing; Ye, Taiyang; Cui, Pengfei; Hua, Qian; Zeng, Huiyan; Zhao, Dezheng

    2016-05-01

    VEGF, upon binding to its endothelial cell specific receptors VEGF-R1 and VEGF-R2, can induce endothelial cell migration, proliferation and angiogenesis. However, the molecular mechanism of these effects still remains unclear. In this study, we investigated whether VEGF promotes human umbilical vascular endothelial cell (HUVEC) migration and proliferation through activator protein-1 transcription factor (AP-1) family. We first showed that VEGF induces immediate-early genes AP-1 family gene expression differentially with the profound induction of JunB (both mRNA and protein) under various conditions (PBS, DMSO or control adenoviruses). The increase in AP-1 mRNA expression occurs primarily at the transcriptional level. Inhibition of AP-1 DNA binding activity by adenovirus expressing a potent dominant negative form of c-Fos (Afos) significantly attenuated VEGF-induced HUVEC migration and proliferation and cyclin D1 expression. Knockdown of JunB with adenovirus expressing JunB shRNA reduces VEGF-induced JunB expression and attenuated HUVEC migration. However the shJunB-expressing virus has no effect on VEGF-induced cyclin D1 protein expression and proliferation. These results suggest that VEGF-induced endothelial migration is mediated primarily by induction of JunB whereas the promotion of endothelial proliferation by VEGF is mediated by JunB-independent AP-1 family members.

  12. Transcriptional Activation of Metalloid Tolerance Genes in Saccharomyces cerevisiae Requires the AP-1–like Proteins Yap1p and Yap8p

    PubMed Central

    Wysocki, Robert; Fortier, Pierre-Karl; Maciaszczyk, Ewa; Thorsen, Michael; Leduc, Anick; Odhagen, Åsa; Owsianik, Grzegorz; Ulaszewski, Stanislaw; Ramotar, Dindial; Tamás, Markus J.

    2004-01-01

    All organisms are equipped with systems for detoxification of the metalloids arsenic and antimony. Here, we show that two parallel pathways involving the AP-1–like proteins Yap1p and Yap8p are required for acquisition of metalloid tolerance in the budding yeast S. cerevisiae. Yap8p is demonstrated to reside in the nucleus where it mediates enhanced expression of the arsenic detoxification genes ACR2 and ACR3. Using chromatin immunoprecipitation assays, we show that Yap8p is associated with the ACR3 promoter in untreated as well as arsenic-exposed cells. Like for Yap1p, specific cysteine residues are critical for Yap8p function. We further show that metalloid exposure triggers nuclear accumulation of Yap1p and stimulates expression of antioxidant genes. Yap1p mutants that are unable to accumulate in the nucleus during H2O2 treatment showed nearly normal nuclear retention in response to metalloid exposure. Thus, our data are the first to demonstrate that Yap1p is being regulated by metalloid stress and to indicate that this activation of Yap1p operates in a manner distinct from stress caused by chemical oxidants. We conclude that Yap1p and Yap8p mediate tolerance by controlling separate subsets of detoxification genes and propose that the two AP-1–like proteins respond to metalloids through distinct mechanisms. PMID:14978214

  13. Synergistic transcriptional activation of the mouse urokinase plasminogen activator (uPA) gene and of its enhancer activator protein 1 (AP1) site by cAMP and retinoic acid.

    PubMed Central

    Mira-Y-Lopez, R; Jaramillo, S; Jing, Y

    1998-01-01

    We have investigated the mechanism whereby all-trans retinoic acid (tRA) potentiates the 8-bromo-cAMP (8-BrcAMP)-dependent transcription of the urokinase plasminogen activator (uPA) gene in SC115 mouse mammary carcinoma cells. Photoaffinity labelling experiments showed that tRA did not alter the cellular content of cAMP-dependent protein kinase regulatory subunits I and II. In agreement with this, nuclear run-on analysis in the presence of the translational inhibitor puromycin demonstrated that the effect of 8-BrcAMP and its potentiation by tRA were independent of protein synthesis. A transiently transfected 6.6 kb uPA 5'-flanking region-chloramphenicol acetyltransferase (CAT) fusion gene mimicked the response of the endogenous uPA gene. Thus 1 mM 8-BrcAMP induced a 100-200% increase in CAT content, 100 nM tRA had no effect and 100 nM tRA+1 mM 8-BrcAMP induced a 300-500% increase in cells co-transfected with tRA receptor and/or 9-cis-RA receptor. Analysis of 5'-deleted constructs showed that the tRA effect required at least two cis regions: -2657 to -2186, encompassing the 100 bp uPA enhancer, and -709 to -324, which exhibited silencing activity. Neither region contained a tRA-response element-like motif. Because tRA receptor and 9-cis-RA receptor interact with activator protein 1 (AP1), we tested whether tRA regulated the uPA enhancer AP1 site in the presence of 8-BrcAMP. We found that a dimer of this site fused to a minimal uPA-CAT fusion gene was responsive to 1 mM 8-BrcAMP (100% CAT increase), not responsive to 100 nM tRA, and synergistically responsive to 100 nM tRA+1 mM 8-BrcAMP (240% CAT increase) in cells co-transfected with Fos and Jun. Synergistic activation of the same construct and of the 6.6 kb uPA-CAT fusion gene was also obtained using tRA and 100 nM PMA. We conclude that multiple cis elements, probably including the uPA enhancer AP1 site, mediate the tRA potentiation of uPA transcription. PMID:9560322

  14. Interplay between TAp73 Protein and Selected Activator Protein-1 (AP-1) Family Members Promotes AP-1 Target Gene Activation and Cellular Growth.

    PubMed

    Subramanian, Deepa; Bunjobpol, Wilawan; Sabapathy, Kanaga

    2015-07-24

    Unlike p53, which is mutated at a high rate in human cancers, its homologue p73 is not mutated but is often overexpressed, suggesting a possible context-dependent role in growth promotion. Previously, we have shown that co-expression of TAp73 with the proto-oncogene c-Jun can augment cellular growth and potentiate transactivation of activator protein (AP)-1 target genes such as cyclin D1. Here, we provide further mechanistic insights into the cooperative activity between these two transcription factors. Our data show that TAp73-mediated AP-1 target gene transactivation relies on c-Jun dimerization and requires the canonical AP-1 sites on target gene promoters. Interestingly, only selected members of the Fos family of proteins such as c-Fos and Fra1 were found to cooperate with TAp73 in a c-Jun-dependent manner to transactivate AP-1 target promoters. Inducible expression of TAp73 led to the recruitment of these Fos family members to the AP-1 target promoters on which TAp73 was found to be bound near the AP-1 site. Consistent with the binding of TAp73 and AP-1 members on the target promoters in a c-Jun-dependent manner, TAp73 was observed to physically interact with c-Jun specifically at the chromatin via its carboxyl-terminal region. Furthermore, co-expression of c-Fos or Fra1 was able to cooperate with TAp73 in potentiating cellular growth, similarly to c-Jun. These data together suggest that TAp73 plays a vital role in activation of AP-1 target genes via direct binding to c-Jun at the target promoters, leading to enhanced loading of other AP-1 family members, thereby leading to cellular growth.

  15. Regulation of AP-1 and NFAT transcription factors during thymic selection of T cells.

    PubMed Central

    Rincon, M; Flavell, R A

    1996-01-01

    The ability of thymocytes to express cytokine genes changes during the different stages of thymic development. Although CD4- CD8- thymocytes are able to produce a wide spectrum of cytokines in response to a T-cell receptor (TcR)-independent stimulus, as they approach the double-positive (DP) CD4+ CD8+ stage, they lose the ability to produce cytokine. After the DP stage, thymocytes become single-positive CD4+ or CD8+ thymocytes which reacquire the ability to secrete cytokines. In an attempt to understand the molecular basis of this specific regulatin, we use AP-1-luciferase and newly generated NFAT-luciferase transgenic mice to analyze the transcriptional and DNA-binding activities of these two transcription factors that are involved in the regulation of cytokine gene expression. Here, we show that both AP-1 and NFAT transcriptional activities are not inducible in the majority of DP cells but that during the differentiation of DP cells to the mature single-positive stage, thymocytes regain this inducibility. Subpopulation analysis demonstrates that this inducibility is reacquired at the DP stage before the down-modulation of one of the coreceptors. Indeed AP-1 inducibility, just like the ability to express the interleukin-2 gene, is reacquired during the differentiation of DP TcRlow CD69low heat-stable antigen (HSA)high thymocytes to DP TcRhigh CD69high HSAhigh cells, which is considered to be the consequence of the first signal that initiates positive selection. We therefore propose that the inability of DP thymocytes to induce AP-1 and NFAT activities is one of the causes for the lack of cytokine gene expression at this stage and that this inducibility is reacquired at the latest stage of DP differentiation as a consequence of positive selection. This could be a mechanism to prevent the activation of DP thymocytes before selection has taken place. PMID:8622652

  16. Multiple Bcl-2 family immunomodulators from vaccinia virus regulate MAPK/AP-1 activation.

    PubMed

    Torres, Alice A; Albarnaz, Jonas D; Bonjardim, Cláudio A; Smith, Geoffrey L

    2016-09-01

    Vaccinia virus (VACV) is a poxvirus and encodes many proteins that modify the host cell metabolism or inhibit the host response to infection. For instance, it is known that VACV infection can activate the mitogen-activated protein kinase (MAPK)/activator protein 1 (AP-1) pathway and inhibit activation of the pro-inflammatory transcription factor NF-κB. Since NF-κB and MAPK/AP-1 share common upstream activators we investigated whether six different VACV Bcl-2-like NF-κB inhibitors can also influence MAPK/AP-1 activation. Data presented show that proteins A52, B14 and K7 each contribute to AP-1 activation during VACV infection, and when expressed individually outwith infection. B14 induced the greatest stimulation of AP-1 and further investigation showed B14 activated mainly the MAPKs ERK (extracellular signal-regulated kinase) and JNK (Jun N-terminal kinase), and their substrate c-Jun (a component of AP-1). These data indicate that the same viral protein can have different effects on distinct signalling pathways, in blocking NF-κB activation whilst leading to MAPK/AP-1 activation.

  17. AP-1 Transcription Factor Serves as a Molecular Switch between Chlamydia pneumoniae Replication and Persistence

    PubMed Central

    Krämer, S.; Crauwels, P.; Bohn, R.; Radzimski, C.; Szaszák, M.; Klinger, M.; Rupp, J.

    2015-01-01

    Chlamydia pneumoniae is a Gram-negative bacterium that causes acute or chronic respiratory infections. As obligate intracellular pathogens, chlamydiae efficiently manipulate host cell processes to ensure their intracellular development. Here we focused on the interaction of chlamydiae with the host cell transcription factor activator protein 1 (AP-1) and its consequence on chlamydial development. During Chlamydia pneumoniae infection, the expression and activity of AP-1 family proteins c-Jun, c-Fos, and ATF-2 were regulated in a time- and dose-dependent manner. We observed that the c-Jun protein and its phosphorylation level significantly increased during C. pneumoniae development. Small interfering RNA knockdown of the c-Jun protein in HEp-2 cells reduced the chlamydial load, resulting in smaller inclusions and significantly lower chlamydial recovery. Furthermore, inhibition of the c-Jun-containing AP-1 complexes using tanshinone IIA changed the replicative infection phenotype into a persistent one. Tanshinone IIA-dependent persistence was characterized by smaller, aberrant inclusions, a strong decrease in the chlamydial load, and significantly reduced chlamydial recovery, as well as by the reversibility of the reduced recovery after the removal of tanshinone IIA. Interestingly, not only was tanshinone IIA treatment accompanied by a significant decrease of ATP levels, but fluorescence live cell imaging analysis by two-photon microscopy revealed that tanshinone IIA treatment also resulted in a decreased fluorescence lifetime of protein-bound NAD(P)H inside the chlamydial inclusion, indicating that chlamydial reticulate bodies have decreased metabolic activity. In all, these data demonstrate that the AP-1 transcription factor is involved in C. pneumoniae development, with tanshinone IIA treatment resulting in persistence. PMID:25895972

  18. Robust dynamic balance of AP-1 transcription factors in a neuronal gene regulatory network

    PubMed Central

    2010-01-01

    Background The octapeptide Angiotensin II is a key hormone that acts via its receptor AT1R in the brainstem to modulate the blood pressure control circuits and thus plays a central role in the cardiac and respiratory homeostasis. This modulation occurs via activation of a complex network of signaling proteins and transcription factors, leading to changes in levels of key genes and proteins. AT1R initiated activity in the nucleus tractus solitarius (NTS), which regulates blood pressure, has been the subject of extensive molecular analysis. But the adaptive network interactions in the NTS response to AT1R, plausibly related to the development of hypertension, are not understood. Results We developed and analyzed a mathematical model of AT1R-activated signaling kinases and a downstream gene regulatory network, with structural basis in our transcriptomic data analysis and literature. To our knowledge, our report presents the first computational model of this key regulatory network. Our simulations and analysis reveal a dynamic balance among distinct dimers of the AP-1 family of transcription factors. We investigated the robustness of this behavior to simultaneous perturbations in the network parameters using a novel multivariate approach that integrates global sensitivity analysis with decision-tree methods. Our analysis implicates a subset of Fos and Jun dependent mechanisms, with dynamic sensitivities shifting from Fos-regulating kinase (FRK)-mediated processes to those downstream of c-Jun N-terminal kinase (JNK). Decision-tree analysis indicated that while there may be a large combinatorial functional space feasible for neuronal states and parameters, the network behavior is constrained to a small set of AP-1 response profiles. Many of the paths through the combinatorial parameter space lead to a dynamic balance of AP-1 dimer forms, yielding a robust AP-1 response counteracting the biological variability. Conclusions Based on the simulation and analysis results, we

  19. Procyanidin B2 3,3(″)-di-O-gallate, a biologically active constituent of grape seed extract, induces apoptosis in human prostate cancer cells via targeting NF-κB, Stat3, and AP1 transcription factors.

    PubMed

    Tyagi, Alpna; Raina, Komal; Shrestha, Suraj Prakash; Miller, Bettina; Thompson, John A; Wempe, Michael F; Agarwal, Rajesh; Agarwal, Chapla

    2014-01-01

    Recently, we identified procyanidin B2 3,3(″)-di-O-gallate (B2G2) as most active constituent of grape seed extract (GSE) for efficacy against prostate cancer (PCa). Isolating large quantities of B2G2 from total GSE is labor intensive and expensive, thereby limiting both efficacy and mechanistic studies with this novel anticancer agent. Accordingly, here we synthesized gram-scale quantities of B2G2, compared it with B2G2 isolated from GSE for possible equivalent biological activity and conducted mechanistic studies. Both B2G2 preparations inhibited cell growth, decreased clonogenicity, and induced cell cycle arrest and apoptotic death, comparable to each other, in various human PCa cell lines. Mechanistic studies focusing on transcription factors involved in apoptotic and survival pathways revealed that B2G2 significantly inhibits NF-κB and activator protein1 (AP1) transcriptional activity and nuclear translocation of signal transducer and activator of transcription3 (Stat3) in PCa cell lines, irrespective of their functional androgen receptor status. B2G2 also decreased survivin expression which is regulated by NF-κB, AP1, and Stat3 and increased cleaved PARP level. In summary, we report B2G2 chemical synthesis at gram-quantity with equivalent biological efficacy against human PCa cell lines and same molecular targeting profiles at key transcription factors level. The synthetic B2G2 will stimulate more research on prostate and possibly other malignancies in preclinical models and clinical translation.

  20. Energy Expenditure and Bone Formation Share a Common Sensitivity to AP-1 Transcription in the Hypothalamus

    PubMed Central

    Rowe, Glenn C.; Vialou, Vincent; Sato, Kazusa; Saito, Hiroaki; Yin, Min; Green, Thomas A.; Lotinun, Sutada; Kveiborg, Marie; Horne, William C.; Nestler, Eric J.; Baron, Roland

    2012-01-01

    The regulation of bone and fat homeostasis and its relationship to energy expenditure has recently been the focus of increased attention due to its potential relevance to osteoporosis, obesity and diabetes. Although central effectors within the hypothalamus have been shown to contribute to the regulation of both energy balance and bone homeostasis, little is known of the underlying mechanisms, including the possible involvement of transcriptional factors within the hypothalamus. Transgenic mice overexpressing ΔFosB, a splice variant of the AP1 transcription factor FosB with mixed agonist-antagonistic properties, have increased energy expenditure and bone mass. Since these mice express ΔFosB in bone, fat and hypothalamus, we sought to determine 1) whether overexpression of ΔFosB within the hypothalamus was sufficient to regulate energy expenditure and whether it would also regulate bone mass, and 2) whether these effects were due to antagonism to AP1. Our results show that stereotactic injection of an adeno-associated virus vector to restrict overexpression of ΔFosB to the ventral hypothalamus of wildtype mice induced a profound increase in both energy expenditure and bone formation and bone mass. This effect was phenocopied, at an even stronger level, by overexpressiong of a dominant-negative DNJunD, a pure AP1 antagonist. Taken together these results suggest that downregulation of AP1 activity in the hypothalamus profoundly increases energy expenditure and bone formation, leading to both a decrease in adipose mass and an increase in bone mass. These findings may have physiological implications since ΔFosB is expressed and regulated in the hypothalamus. PMID:22461201

  1. ACTIVATION OF AP-1 IN UROTSA CELLS BY METHYLATED ARSENICALS

    EPA Science Inventory

    ACTIVATION OF AP-1 IN UROTSA CELLS BY METHYLATED TRIVALENT ARSENICALS. Z Drobna1, I Jaspers2, D J Thomas3 and M Styblo1. 1Department of Pediatrics; 2Center for Environmental Medicine and Lung Biology, University of North Carolina at Chapel Hill, NC, USA; 3US EPA, RTP, NC, USA.

  2. ACTIVATION OF AP-1 IN UROTSA CELLS BY METHYLATED ARSENICALS

    EPA Science Inventory

    ACTIVATION OF AP-1 IN UROTSA CELLS BY METHYLATED TRIVALENT ARSENICALS. Z Drobna1, I Jaspers2, D J Thomas3 and M Styblo1. 1Department of Pediatrics; 2Center for Environmental Medicine and Lung Biology, University of North Carolina at Chapel Hill, NC, USA; 3US EPA, RTP, NC, USA.

  3. Activator protein-1 (AP-1) and response to pathogen infection in the Hong Kong oyster (Crassostrea hongkongensis).

    PubMed

    Xiang, Zhiming; Qu, Fufa; Li, Jun; Qi, Lin; Yang, Zhang; Kong, Xiaoyu; Yu, Ziniu

    2014-01-01

    Growing evidence suggests that the transcription factor activator protein-1 (AP-1), a downstream target of mitogen-activated protein kinase (MAPK) signaling, plays a major role in stimulating the synthesis of immune effector molecules during innate immune responses. We have characterized ChAP-1, an AP-1-like protein in Crassostrea hongkongensis that is a member of the AP-1 family of proteins. ChAP-1 is composed of 290 amino acid residues with a Jun and bZIP domain at the N- and C-termini, respectively, a structure similar to that of known Ap-1 proteins. ChAP-1 mRNA is expressed in several tissues analyzed, with highest expression in the mantle. Expression of ChAP-1 increases in response to Vibrio alginolyticus, Salmo haemolyticus or Salmo cerevisiae infection and, despite the location of GFP-tagged full-length ChAP-1 protein in the cytoplasm, ChAP-1 activates the transcription of an L8G5-luc reporter gene, and its over-expression can also activate the AP-1-Luc reporter gene in HEK293T cells.

  4. Differences in expression of transcription factor AP-1 in human promyelocytic HL-60 cells during differentiation towards macrophages versus granulocytes.

    PubMed Central

    Mollinedo, F; Gajate, C; Tugores, A; Flores, I; Naranjo, J R

    1993-01-01

    Commitment of HL-60 cells to macrophage or granulocytic differentiation was achieved by incubation with 4 beta-phorbol 12-myristate 13-acetate (PMA) for 30-60 min or with dimethyl sulphoxide (DMSO) for 24 h respectively. The commitment stage towards PMA-induced macrophage differentiation was associated with increases in jun B and c-fos mRNA levels, as well as with an increase in the binding activity of transcription factor AP-1. Nevertheless, gel retardation analysis indicated that the AP-1 activity detected in untreated cells was drastically reduced during the commitment stage of DMSO-induced HL-60 differentiation towards granulocytes. When HL-60 cells were treated with sodium butyrate, which induced monocytic differentiation, a remarkable increase in AP-1 binding activity was detected. Treatment of HL-60 cells with 1 alpha,25-dihydroxyvitamin D3, another monocytic differentiation agent, induced a weak, but appreciable, increase in AP-1 activity. Furthermore, addition of sodium butyrate or 1 alpha,25-dihydroxyvitamin D3 to HL-60 cells induced the expression of c-fos, c-jun, jun B and jun D proto-oncogenes. In contrast, when HL-60 cells were treated with retinoic acid, a granulocytic differentiation inducer, no enhanced AP-1 binding activity was observed, and only a weak increase in jun D mRNA level was detected. These data indicate that formation of AP-1 is not required for the induction of HL-60 differentiation towards granulocytes, whereas induction of monocytic differentiation is correlated with an increase in AP-1 activity. The differential expression of AP-1 activity may be critical in the differentiation of HL-60 cells towards monocytic or granulocytic lineages. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 PMID:8363564

  5. Spleen Tyrosine Kinase Regulates AP-1 Dependent Transcriptional Response to Minimally Oxidized LDL

    PubMed Central

    Choi, Soo-Ho; Wiesner, Philipp; Almazan, Felicidad; Kim, Jungsu; Miller, Yury I.

    2012-01-01

    Oxidative modification of low-density lipoprotein (LDL) turns it into an endogenous ligand recognized by pattern-recognition receptors. We have demonstrated that minimally oxidized LDL (mmLDL) binds to CD14 and mediates TLR4/MD-2-dependent responses in macrophages, many of which are MyD88-independent. We have also demonstrated that the mmLDL activation leads to recruitment of spleen tyrosine kinase (Syk) to TLR4 and TLR4 and Syk phosphorylation. In this study, we produced a macrophage-specific Syk knockout mouse and used primary Syk−/− macrophages in our studies. We demonstrated that Syk mediated phosphorylation of ERK1/2 and JNK, which in turn phosphorylated c-Fos and c-Jun, respectively, as assessed by an in vitro kinase assay. c-Jun phosphorylation was also mediated by IKKε. c-Jun and c-Fos bound to consensus DNA sites and thereby completed an AP-1 transcriptional complex and induced expression of CXCL2 and IL-6. These results suggest that Syk plays a key role in TLR4-mediated macrophage responses to host-generated ligands, like mmLDL, with subsequent activation of an AP-1 transcription program. PMID:22384232

  6. Cervical cancer stem cells manifest radioresistance: Association with upregulated AP-1 activity.

    PubMed

    Tyagi, Abhishek; Vishnoi, Kanchan; Kaur, Harsimrut; Srivastava, Yogesh; Roy, Bal Gangadhar; Das, Bhudev C; Bharti, Alok C

    2017-07-06

    Transcription factor AP-1 plays a central role in HPV-mediated cervical carcinogenesis. AP-1 has also been implicated in chemo-radio-resistance but the mechanism(s) remained unexplored. In the present study, cervical cancer stem-like cells (CaCxSLCs) isolated and enriched from cervical cancer cell lines SiHa and C33a demonstrated an elevated AP-1 DNA-binding activity in comparison to non-stem cervical cancer cells. Upon UV-irradiation, CaCxSLCs showed a UV exposure duration-dependent higher proliferation and highly increased AP-1 activity whereas it was completely abolished in non-stem cancer cells. CaCxSLCs also showed differential overexpression of c-Fos and c-Jun at transcript as well as in protein level. The loss of AP-1 activity and expression was accompanied by decrease in cell viability and proliferation in UV-irradiated non-stem cancer cells. Interestingly, CaCxSLCs treated with curcumin prior to UV-irradiation abolished AP-1 activity and a concomitant reduction in SP cells leading to abrogation of sphere forming ability, loss of proliferation, induction of apoptosis and the cells were poorly tumorigenic. The curcumin pre-treatment abolished the expression of c-Fos and c-Jun but upregulated Fra-1 expression in UV-irradiated CaCxSLCs. Thus, the study suggests a critical role of AP-1 protein in the manifestation of radioresistance but targeting with curcumin helps in radiosensitizing CaCxSLCs through upregulation of Fra-1.

  7. Protein kinase C-theta isoenzyme selective stimulation of the transcription factor complex AP-1 in T lymphocytes.

    PubMed Central

    Baier-Bitterlich, G; Uberall, F; Bauer, B; Fresser, F; Wachter, H; Grunicke, H; Utermann, G; Altman, A; Baier, G

    1996-01-01

    T-lymphocyte stimulation requires activation of several protein kinases, including the major phorbol ester receptor protein kinase C (PKC), ultimately leading to induction of lymphokines, such as interleukin-2 (IL-2). The revelant PKC isoforms which are involved in the activation cascades of nuclear transcription factors involved in IL-2 production have not yet been clearly defined. We have examined the potential role of two representative PKC isoforms in the induction of the IL-2 gene, i.e., PKC-alpha and PKC-theta, the latter being expressed predominantly in hematopoietic cell lines, particularly T cells. Similar to that of PKC-alpha, PKC-theta overexpression in murine EL4 thymoma cells caused a significant increase in phorbol 12-myristate 13-acetate (PMA)-induced transcriptional activation of full-length IL-2-chloramphenicol acetyltransferase (CAT) and NF-AT-CAT but not of NF-IL2A-CAT or NF-kappaB promoter-CAT reporter gene constructs. Importantly, the critical AP-1 enhancer element was differentially modulated by these two distinct PKC isoenzymes, since only PKC-theta but not PKC-alpha overexpression resulted in an approximately 2.8-fold increase in AP-1-collagenase promoter CAT expression in comparison with the vector control. Deletion of the AP-1 enhancer site in the collagenase promoter rendered it unresponsive to PKC-theta. Expression of a constitutively active mutant PKC-theta A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-theta K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-RasS17N completely inhibited the PKC-O A148E-induced signal, PKC-O. Expression of a constitutively active mutant PKC-O A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation

  8. Luteolin, a flavonoid, inhibits AP-1 activation by basophils

    SciTech Connect

    Hirano, Toru; Higa, Shinji; Arimitsu, Junsuke; Naka, Tetsuji; Ogata, Atsushi; Shima, Yoshihito; Fujimoto, Minoru; Yamadori, Tomoki; Ohkawara, Tomoharu; Kuwabara, Yusuke; Kawai, Mari; Matsuda, Hisashi; Yoshikawa, Masayuki; Maezaki, Naoyoshi; Tanaka, Tetsuaki; Kawase, Ichiro; Tanaka, Toshio . E-mail: ttanak@imed3.med.osaka-u.ac.jp

    2006-02-03

    Flavonoids including luteolin, apigenin, and fisetin are inhibitors of IL-4 synthesis and CD40 ligand expression by basophils. This study was done to search for compounds with greater inhibitory activity of IL-4 expression and to clarify the molecular mechanisms through which flavonoids inhibit their expression. Of the 37 flavonoids and related compounds examined, ayanin, luteolin, and apigenin were the strongest inhibitors of IL-4 production by purified basophils in response to anti-IgE antibody plus IL-3. Luteolin did not suppress Syk or Lyn phosphorylation in basophils, nor did suppress p54/46 SAPK/JNK, p38 MAPK, and p44/42 MAPK activation by a basophilic cell line, KU812 cells, stimulated with A23187 and PMA. However, luteolin did inhibit phosphorylation of c-Jun and DNA binding activity of AP-1 in nuclear lysates from stimulated KU812 cells. These results provide a fundamental structure of flavonoids for IL-4 inhibition and demonstrate a novel action of flavonoids that suppresses the activation of AP-1.

  9. The transcription factor Ets21C drives tumor growth by cooperating with AP-1

    PubMed Central

    Toggweiler, Janine; Willecke, Maria; Basler, Konrad

    2016-01-01

    Tumorigenesis is driven by genetic alterations that perturb the signaling networks regulating proliferation or cell death. In order to block tumor growth, one has to precisely know how these signaling pathways function and interplay. Here, we identified the transcription factor Ets21C as a pivotal regulator of tumor growth and propose a new model of how Ets21C could affect this process. We demonstrate that a depletion of Ets21C strongly suppressed tumor growth while ectopic expression of Ets21C further increased tumor size. We confirm that Ets21C expression is regulated by the JNK pathway and show that Ets21C acts via a positive feed-forward mechanism to induce a specific set of target genes that is critical for tumor growth. These genes are known downstream targets of the JNK pathway and we demonstrate that their expression not only depends on the transcription factor AP-1, but also on Ets21C suggesting a cooperative transcriptional activation mechanism. Taken together we show that Ets21C is a crucial player in regulating the transcriptional program of the JNK pathway and enhances our understanding of the mechanisms that govern neoplastic growth. PMID:27713480

  10. Staphylococcus aureus induces TGF-β1 and bFGF expression through the activation of AP-1 and NF-κB transcription factors in bovine mammary gland fibroblasts.

    PubMed

    Wu, Jianmei; Ding, Yulin; Bi, Yannan; Wang, Yi; Zhi, Yu; Wang, Jinling; Wang, Fenglong

    2016-06-01

    Staphylococcus aureus is a common Gram-positive pathogen that causes bovine mastitis, a persistent infection of the bovine mammary gland. To better understand the importance of bovine mammary fibroblasts (BMFBs) and the roles of the TLR-NF-κB and TLR-AP-1 signaling pathways in the regulation of S. aureus-associated mastitis and mammary fibosis, BMFBs cultured in vitro were stimulated with different concentrations of heat-inactivated S. aureus to analyze the gene and protein expression of toll-like receptor 2 (TLR2), toll-like receptor 4 (TLR4), transforming growth factor beta 1 (TGF-β1), basic fibroblast growth factor (bFGF) as well as the protein expression of nuclear factor-kappa B (NF-κB) and activation protein-1 (AP-1) by means of quantitative polymerase chain reaction (qPCR) and western blotting, respectively. Specific NF-κB and AP-1 inhibitors were also used to investigate their effects on the regulation of TGF-β1 and bFGF expression. The results indicated that, in addition to increasing mRNA and protein expression of TLR2 and TLR4, S. aureus could also upregulate TGF-β1 and bFGF mRNA expression and secretion through the activation of NF-κB and AP-1. The increase in TGF-β1 and bFGF expression was shown to be inhibited by AP-1- and NF-κB-specific inhibitors. Taken together, S. aureus induces TGF-β1 and bFGF expression through the activation of AP-1 and NF-κB in BMFBs. This information offers new potential targets for the treatment of bovine mammary fibrosis.

  11. Regulation of the human fas promoter by YB-1, Puralpha and AP-1 transcription factors.

    PubMed

    Lasham, A; Lindridge, E; Rudert, F; Onrust, R; Watson, J

    2000-07-11

    Fas (CD95/Apo-1) gene expression is dysregulated in a number of diseased states. Towards understanding the regulation of fas gene expression, we previously identified activator and repressor elements within the human fas promoter. Using a combination of expression screening and reporter gene assays, we have identified transcription factors which bind to these elements and thereby regulate transcription of the fas promoter. These are three single-stranded DNA binding proteins, YB-1, Puralpha and Purbeta and two components of the AP-1 complex, c-Fos and c-Jun. c-Jun is a potent transcriptional activator of fas and stimulated expression levels up to 184-fold in reporter gene assays. Co-expression with c-Fos abrogated c-Jun-mediated activation. YB-1 and Puralpha are transcriptional repressors of fas and decreased basal transcription by 60-fold in reporter gene assays. Purbeta was predominantly an antagonist of YB-1/Puralpha-mediated repression. Overexpression of YB-1 and Puralpha in Jurkat cells was shown to reduce the level of cell surface Fas staining, providing further evidence that these proteins regulate the fas promoter. It has been suggested that YB-1 plays a role in cell proliferation as an activator of growth-associated gene expression. We have shown that YB-1 is a repressor of a cell death-associated gene fas. These results suggest that YB-1 may play an important role in controlling cell survival by co-ordinately regulating the expression of cell growth-associated and death-associated genes.

  12. E1A dependent up-regulation of c-jun/AP-1 activity.

    PubMed Central

    Kitabayashi, I; Chiu, R; Gachelin, G; Yokoyama, K

    1991-01-01

    E1A, the early region 1A transcription unit of human adenovirus, exhibits multiple functions that regulate the expression of some cellular genes and promote cell growth and division. We found that E1A stimulated c-jun gene expression at least fifty-fold in rat 3Y1 cells in a serum-independent manner, concomitantly with E1A down-regulation of jun B expression. The E1A-dependent induction of c-jun transcription resulted in increase amount of cJun/AP1. This induction was mediated by the enhancement of the binding activity of the transcription factor cJun/AP1 to an AP1 binding site in the c-jun promoter. Additionally, this induction can be repressed by introducing junB into the cells. Taken collectively, these results suggest that the differential expression of two closely related proteins greatly expands their cellular regulation. Induction of c-jun expression by E1A as well as c-jun autoregulation may amplify the action of E1A during adenovirus infection. Therefore, some of the biological effects of E1A may include mediating the constitutive activation of c-jun, which is important in transcriptional regulation and oncogenic transformation. Images PMID:1826351

  13. AP1 transcription factors are required to maintain the peripheral taste system

    PubMed Central

    Shandilya, Jayasha; Gao, Yankun; Nayak, Tapan K; Roberts, Stefan G E; Medler, Kathryn F

    2016-01-01

    The sense of taste is used by organisms to achieve the optimal nutritional requirement and avoid potentially toxic compounds. In the oral cavity, taste receptor cells are grouped together in taste buds that are present in specialized taste papillae in the tongue. Taste receptor cells are the cells that detect chemicals in potential food items and transmit that information to gustatory nerves that convey the taste information to the brain. As taste cells are in contact with the external environment, they can be damaged and are routinely replaced throughout an organism's lifetime to maintain functionality. However, this taste cell turnover loses efficiency over time resulting in a reduction in taste ability. Currently, very little is known about the mechanisms that regulate the renewal and maintenance of taste cells. We therefore performed RNA-sequencing analysis on isolated taste cells from 2 and 6-month-old mice to determine how alterations in the taste cell-transcriptome regulate taste cell maintenance and function in adults. We found that the activator protein-1 (AP1) transcription factors (c-Fos, Fosb and c-Jun) and genes associated with this pathway were significantly downregulated in taste cells by 6 months and further declined at 12 months. We generated conditional c-Fos-knockout mice to target K14-expressing cells, including differentiating taste cells. c-Fos deletion caused a severe perturbation in taste bud structure and resulted in a significant reduction in the taste bud size. c-Fos deletion also affected taste cell turnover as evident by a decrease in proliferative marker, and upregulation of the apoptotic marker cleaved-PARP. Thus, AP1 factors are important regulators of adult taste cell renewal and their downregulation negatively impacts taste maintenance. PMID:27787515

  14. Thioredoxin reductase regulates AP-1 activity as well as thioredoxin nuclear localization via active cysteines in response to ionizing radiation.

    PubMed

    Karimpour, Shervin; Lou, Junyang; Lin, Lilie L; Rene, Luis M; Lagunas, Lucio; Ma, Xinrong; Karra, Sreenivasu; Bradbury, C Matthew; Markovina, Stephanie; Goswami, Prabhat C; Spitz, Douglas R; Hirota, Kiichi; Kalvakolanu, Dhananjaya V; Yodoi, Junji; Gius, David

    2002-09-12

    A recently identified class of signaling factors uses critical cysteine motif(s) that act as redox-sensitive 'sulfhydryl switches' to reversibly modulate specific signal transduction cascades regulating downstream proteins with similar redox-sensitive sites. For example, signaling factors such as redox factor-1 (Ref-1) and transcription factors such as the AP-1 complex both contain redox-sensitive cysteine motifs that regulate activity in response to oxidative stress. The mammalian thioredoxin reductase-1 (TR) is an oxidoreductase selenocysteine-containing flavoprotein that also appears to regulate multiple downstream intracellular redox-sensitive proteins. Since ionizing radiation (IR) induces oxidative stress as well as increases AP-1 DNA-binding activity via the activation of Ref-1, the potential roles of TR and thioredoxin (TRX) in the regulation of AP-1 activity in response to IR were investigated. Permanently transfected cell lines that overexpress wild type TR demonstrated constitutive increases in AP-1 DNA-binding activity as well as AP-1-dependent reporter gene expression, relative to vector control cells. In contrast, permanently transfected cell lines expressing a TR gene with the active site cysteine motif deleted were unable to induce AP-1 activity or reporter gene expression in response to IR. Transient genetic overexpression of either the TR wild type or dominant-negative genes demonstrated similar results using a transient assay system. One mechanism through which TR regulates AP-1 activity appears to involve TRX sub-cellular localization, with no change in the total TRX content of the cell. These results identify a novel function of the TR enzyme as a signaling factor in the regulation of AP-1 activity via a cysteine motif located in the protein.

  15. Specific activation of human interleukin-5 depends on de novo synthesis of an AP-1 complex.

    PubMed

    Schwenger, Gretchen T F; Kok, Chee Choy; Arthaningtyas, Estri; Thomas, Marc A; Sanderson, Colin J; Mordvinov, Viatcheslav A

    2002-12-06

    It is clear from the biology of eosinophilia that a specific regulatory mechanism must exist. Because interleukin-5 (IL5) is the key regulatory cytokine, it follows that a gene-specific control of IL5 expression must exist that differs even from closely related cytokines such as IL4. Two features of IL5 induction make it unique compared with other cytokines; first, induction by cyclic adenosine monophosphate (cAMP), which inhibits other T-cell-derived cytokines, and second, sensitivity to protein synthesis inhibitors, which have no effect on other cytokines. This study has utilized the activation of different transcription factors by different stimuli in a human T-cell line to study the role of conserved lymphokine element 0 (CLE0) in the specific induction of IL5. In unstimulated cells the ubiquitous Oct-1 binds to CLE0. Stimulation induces de novo synthesis of the AP-1 members JunD and Fra-2, which bind to CLE0. The amount of IL5 produced correlates with the production of the AP-1 complex, suggesting a key role in IL5 expression. The formation of the AP-1 complex is essential, but the rate-limiting step is the synthesis of AP-1, especially Fra-2. This provides an explanation for the sensitivity of IL5 to protein synthesis inhibitors and a mechanism for the specific induction of IL5 compared with other cytokines.

  16. TAK1 regulates NF-{Kappa}B and AP-1 activation in airway epithelial cells following RSV infection

    SciTech Connect

    Dey, Nilay; Liu Tianshuang; Garofalo, Roberto P.; Casola, Antonella

    2011-09-30

    Respiratory syncytial virus (RSV) is the most common cause of epidemic respiratory diseases in infants and young children. RSV infection of airway epithelial cells induces the expression of immune/inflammatory genes through the activation of a subset of transcription factors, including Nuclear Factor-{kappa}B (NF-{kappa}B) and AP-1. In this study, we have investigated the signaling pathway leading to activation of these two transcription factors in response to RSV infection. Our results show that IKK{beta} plays a key role in viral-induced NF-{kappa}B activation, while JNK regulates AP-1-dependent gene transcription, as demonstrated by using kinase inactive proteins and chemical inhibitors of the two kinases. Inhibition of TAK1 activation, by overexpression of kinase inactive TAK1 or using cells lacking TAK1 expression, significantly reduced RSV-induced NF-{kappa}B and AP-1 nuclear translocation and DNA-binding activity, as well as NF-{kappa}B-dependent gene expression, identifying TAK1 as an important upstream signaling molecule regulating RSV-induced NF-{kappa}B and AP-1 activation. - Highlights: > IKK{beta} is a major kinase involved in RSV-induced NF-{kappa}B activation. > JNK regulates AP-1-dependent gene transcription in RSV infection. > TAK1 is a critical upstream signaling molecule for both pathways in infected cells.

  17. AMP-activated protein kinase α1-sensitive activation of AP-1 in cardiomyocytes.

    PubMed

    Voelkl, Jakob; Alesutan, Ioana; Primessnig, Uwe; Feger, Martina; Mia, Sobuj; Jungmann, Andreas; Castor, Tatsiana; Viereck, Robert; Stöckigt, Florian; Borst, Oliver; Gawaz, Meinrad; Schrickel, Jan Wilko; Metzler, Bernhard; Katus, Hugo A; Müller, Oliver J; Pieske, Burkert; Heinzel, Frank R; Lang, Florian

    2016-08-01

    AMP-activated protein kinase (Ampk) regulates myocardial energy metabolism and plays a crucial role in the response to cell stress. In the failing heart, an isoform shift of the predominant Ampkα2 to the Ampkα1 was observed. The present study explored possible isoform specific effects of Ampkα1 in cardiomyocytes. To this end, experiments were performed in HL-1 cardiomyocytes, as well as in Ampkα1-deficient and corresponding wild-type mice and mice following AAV9-mediated cardiac overexpression of constitutively active Ampkα1. As a result, in HL-1 cardiomyocytes, overexpression of constitutively active Ampkα1 increased the phosphorylation of Pkcζ. Constitutively active Ampkα1 further increased AP-1-dependent transcriptional activity and mRNA expression of the AP-1 target genes c-Fos, Il6 and Ncx1, effects blunted by Pkcζ silencing. In HL-1 cardiomyocytes, angiotensin-II activated AP-1, an effect blunted by silencing of Ampkα1 and Pkcζ, but not of Ampkα2. In wild-type mice, angiotensin-II infusion increased cardiac Ampkα1 and cardiac Pkcζ protein levels, as well as c-Fos, Il6 and Ncx1 mRNA expression, effects blunted in Ampkα1-deficient mice. Pressure overload by transverse aortic constriction (TAC) similarly increased cardiac Ampkα1 and Pkcζ abundance as well as c-Fos, Il6 and Ncx1 mRNA expression, effects again blunted in Ampkα1-deficient mice. AAV9-mediated cardiac overexpression of constitutively active Ampkα1 increased Pkcζ protein abundance and the mRNA expression of c-Fos, Il6 and Ncx1 in cardiac tissue. In conclusion, Ampkα1 promotes myocardial AP-1 activation in a Pkcζ-dependent manner and thus contributes to cardiac stress signaling.

  18. Naturally occurring phenolic acids modulate TPA-induced activation of EGFR, AP-1, and STATs in mouse epidermis.

    PubMed

    Cichocki, Michał; Dałek, Miłosz; Szamałek, Mateusz; Baer-Dubowska, Wanda

    2014-01-01

    Epidermal growth factor receptor (EGFR) plays an important role in epithelial carcinogenesis and appears to be involved in STATs activation. In this study we investigated the possible interference of naturally occurring phenolic acids with EGFR, activator protein-1 (AP-1), and signal transducers and activators of transcription (STATs) pathways activated by topical application of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in Balb/c mice epidermis. Pretreatment with tannic or chlorogenic acid resulted in a significant decrease in the phosphorylation of EGFR Y-1068 and Y-1173 tyrosine residues, which was accompanied by reduced activation of AP-1. Tannic acid decreased also the c-Jun AP-1 subunit level and binding to TPA response element (TRE) (3- and 2-fold in comparison with TPA-treated group respectively). Simultaneous reduction of JNK activity might be responsible for reduced activation of AP-1. In contrast to these more complex phenolics, protocatechuic acid increased the activity of JNK and was also the most efficient inhibitor of STATs activation. These results indicate that naturally occurring phenolic acids, by decreasing EGFR, AP-1, and STATs activation, may modulate other elements both upstream and downstream in these pathways and thus inhibit the tumor development. Although more complex phenolics affect mainly the EGFR/AP-1 pathway, STATs seem to be the most important targets for simple compounds, such as protocatechuic acid.

  19. The AP-1 Transcription Factor c-Jun Promotes Arthritis by Regulating Cyclooxygenase-2 and Arginase-1 Expression in Macrophages.

    PubMed

    Hannemann, Nicole; Jordan, Jutta; Paul, Sushmita; Reid, Stephen; Baenkler, Hanns-Wolf; Sonnewald, Sophia; Bäuerle, Tobias; Vera, Julio; Schett, Georg; Bozec, Aline

    2017-05-01

    Activation of proinflammatory macrophages is associated with the inflammatory state of rheumatoid arthritis. Their polarization and activation are controlled by transcription factors such as NF-κB and the AP-1 transcription factor member c-Fos. Surprisingly, little is known about the role of the AP-1 transcription factor c-Jun in macrophage activation. In this study, we show that mRNA and protein levels of c-Jun are increased in macrophages following pro- or anti-inflammatory stimulations. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment cluster analyses of microarray data using wild-type and c-Jun-deleted macrophages highlight the central function of c-Jun in macrophages, in particular for immune responses, IL production, and hypoxia pathways. Mice deficient for c-Jun in macrophages show an amelioration of inflammation and bone destruction in the serum-induced arthritis model. In vivo and in vitro gene profiling, together with chromatin immunoprecipitation analysis of macrophages, revealed direct activation of the proinflammatory factor cyclooxygenase-2 and indirect inhibition of the anti-inflammatory factor arginase-1 by c-Jun. Thus, c-Jun regulates the activation state of macrophages and promotes arthritis via differentially regulating cyclooxygenase-2 and arginase-1 levels. Copyright © 2017 by The American Association of Immunologists, Inc.

  20. Human TMEM174 that is highly expressed in kidney tissue activates AP-1 and promotes cell proliferation

    SciTech Connect

    Wang, Pingzhang; Sun, Bo; Hao, Dongxia; Zhang, Xiujun; Shi, Taiping; Ma, Dalong

    2010-04-16

    Mitogen-activated protein kinase (MAPK) cascades play an important role in regulation of AP-1 activity through the phosphorylation of distinct substrates. In the present study, we identified a novel protein, TMEM174, whose RNA transcripts are highly expressed in human kidney tissue. TMEM174 is comprised of 243 amino acids, and contains two predicted transmembrane helices which determine its subcellular localization in endoplasmic reticulum and influences its functions. Over-expression of TMME174 enhanced the transcriptional activity of AP-1 and promoted cell proliferation, whereas the truncated mutant TMEM174{Delta}TM without the transmembrane regions did not retain these functions. The possible mechanism of activation of AP-1 by TMEM174 was further examined. Our results suggest the potential role of TMEM174 in renal development and physiological function.

  1. The function and transcriptome analysis of a bZIP transcription factor CgAP1 in Colletotrichum gloeosporioides.

    PubMed

    Li, Xiaoyu; Wu, Yateng; Liu, Zhiqiang; Zhang, Chenghui

    2017-04-01

    Colletotrichum gloeosporioides is an important pathogen of anthracnose, which is able to infect numerous crops in tropical and subtropical regions, causing great economic losses. To investigate the fungal response to host-generated reactive oxygen species (ROS), we cloned and characterized the CgAP1 gene of C. gloeosporioides. CgAP1 encoded a bZIP transcription factor which had a bZIP DNA-binding domain and two cysteine-rich domains structurally and functionally related to Saccharomyces cerevisiae YAP1. Deletion of CgAP1 in C. gloeosporioides resulted in increasing sensitivity to H2O2, changes in cell wall integrity and loss of pathogenicity. To understand the regulatory network of CgAP1, RNA sequencing was used to identify differentially expressed genes in the CgAP1 mutant. It was shown that several genes involved in ROS detoxification and cell wall integrity were affected by CgAP1. Moreover, CgAP1 was also involved in many biological processes especially ribosome, cellular transport and amino acid metabolism. In conclusion, CgAP1 is an important transcription factor involved in oxidative stress, cell wall integrity and pathogenicity in C. gloeosporioides. Copyright © 2017 Elsevier GmbH. All rights reserved.

  2. Enhanced Antimicrobial Activity of AamAP1-Lysine, a Novel Synthetic Peptide Analog Derived from the Scorpion Venom Peptide AamAP1

    PubMed Central

    Almaaytah, Ammar; Tarazi, Shadi; Abu-Alhaijaa, Ahmad; Altall, Yara; Alshar’i, Nizar; Bodoor, Khaldon; Al-Balas, Qosay

    2014-01-01

    There is great interest in the development of antimicrobial peptides as a potentially novel class of antimicrobial agents. Several structural determinants are responsible for the antimicrobial and cytolytic activity of antimicrobial peptides. In our study, a new synthetic peptide analog, AamAP1-Lysine from the naturally occurring scorpion venom antimicrobial peptide AamAP1, was designed by modifying the parent peptide in order to increase the positive charge and optimize other physico-chemical parameters involved in antimicrobial activity. AamAP1-Lysine displayed potent antibacterial activity against Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration was in the range of 5 to 15 µM with a 10 fold increase in potency over the parent peptide. The hemolytic and antiproliferative activity of AamAP1-Lysine against eukaryotic mammalian cells was minimal at the concentration range needed to inhibit bacterial growth. The antibacterial mechanism analysis indicated that AamAP1-Lysine is probably inducing bacterial cell death through membrane damage and permeabilization determined by the release of β-galactosidase enzyme from peptide treated E. coli cells. DNA binding studies revealed that AamAP1-Lysine caused complete retardation of DNA migration and could display intracellular activities in addition to the membrane permeabilization mode of action reported earlier. In conclusion, AamAP1-Lysine could prove to be a potential candidate for antimicrobial drug development in future studies. PMID:24776889

  3. Asymmetric Recognition of Nonconsensus AP-1 Sites by Fos-Jun and Jun-Jun Influences Transcriptional Cooperativity with NFAT1

    PubMed Central

    Ramirez-Carrozzi, Vladimir; Kerppola, Tom

    2003-01-01

    Many regulatory elements in eukaryotic promoters do not correspond to optimal recognition sequences for the transcription factors that regulate promoter function by binding to the elements. The sequence of the binding site may influence the structural and functional properties of regulatory protein complexes. Fos-Jun heterodimers were found to bind nonconsensus AP-1 sites in a preferred orientation. Oriented Fos-Jun heterodimer binding was attributed to nonidentical recognition of the two half-sites by Fos and Jun. Jun bound preferentially to the consensus half-site, whereas Fos was able to bind nonconsensus half-sites. The orientation of heterodimer binding affected the transcriptional cooperativity of Fos-Jun-NFAT1 complexes at composite regulatory elements in mammalian cells. Jun dimerization with Fos versus ATF2 caused it to bind opposite half-sites at nonconsensus AP-1 elements. Similarly, ATF2 bound to opposite half-sites in Fos-ATF2-NFAT1 and ATF2-Jun-NFAT1 complexes. The orientations of nonconsensus AP-1 sites within composite regulatory elements affected the cooperativity of Fos-Jun as well as Jun-Jun binding with NFAT1. Since Jun homodimers cannot bind to AP-1 sites in a preferred orientation, the effects of the orientations of nonconsensus AP-1 sites on the stabilities of Jun-Jun-NFAT1 complexes are likely to be due to asymmetric conformational changes in the two subunits of the homodimer. Nonconsensus AP-1 site orientation also affected the synergy of transcription activation between Jun homodimers and NFAT1 at composite regulatory elements. The asymmetric recognition of nonconsensus AP-1 sites can therefore influence the transcriptional activities of Fos and Jun both through effects on the orientation of heterodimer binding and through differential conformational changes in the two subunits of the dimer. PMID:12588992

  4. Heparin (GAG-hed) inhibits LCR activity of Human Papillomavirus type 18 by decreasing AP1 binding

    PubMed Central

    Villanueva, Rita; Morales-Peza, Néstor; Castelán-Sánchez, Irma; García-Villa, Enrique; Tapia, Rocio; Cid-Arregui, Ángel; García-Carrancá, Alejandro; López-Bayghen, Esther; Gariglio, Patricio

    2006-01-01

    Background High risk HPVs are causative agents of anogenital cancers. Viral E6 and E7 genes are continuously expressed and are largely responsible for the oncogenic activity of these viruses. Transcription of the E6 and E7 genes is controlled by the viral Long Control Region (LCR), plus several cellular transcription factors including AP1 and the viral protein E2. Within the LCR, the binding and activity of the transcription factor AP1 represents a key regulatory event in maintaining E6/E7 gene expression and uncontrolled cell proliferation. Glycosaminoglycans (GAGs), such as heparin, can inhibit tumour growth; they have also shown antiviral effects and inhibition of AP1 transcriptional activity. The purpose of this study was to test the heparinoid GAG-hed, as a possible antiviral and antitumoral agent in an HPV18 positive HeLa cell line. Methods Using in vivo and in vitro approaches we tested GAG-hed effects on HeLa tumour cell growth, cell proliferation and on the expression of HPV18 E6/E7 oncogenes. GAG-hed effects on AP1 binding to HPV18-LCR-DNA were tested by EMSA. Results We were able to record the antitumoral effect of GAG-hed in vivo by using as a model tumours induced by injection of HeLa cells into athymic female mice. The antiviral effect of GAG-hed resulted in the inhibition of LCR activity and, consequently, the inhibition of E6 and E7 transcription. A specific diminishing of cell proliferation rates was observed in HeLa but not in HPV-free colorectal adenocarcinoma cells. Treated HeLa cells did not undergo apoptosis but the percentage of cells in G2/M phase of the cell cycle was increased. We also detected that GAG-hed prevents the binding of the transcription factor AP1 to the LCR. Conclusion Direct interaction of GAG-hed with the components of the AP1 complex and subsequent interference with its ability to correctly bind specific sites within the viral LCR may contribute to the inhibition of E6/E7 transcription and cell proliferation. Our data

  5. Structural basis for recruitment and activation of the AP-1 clathrin adaptor complex by Arf1.

    PubMed

    Ren, Xuefeng; Farías, Ginny G; Canagarajah, Bertram J; Bonifacino, Juan S; Hurley, James H

    2013-02-14

    AP-1 is a clathrin adaptor complex that sorts cargo between the trans-Golgi network and endosomes. AP-1 recruitment to these compartments requires Arf1-GTP. The crystal structure of the tetrameric core of AP-1 in complex with Arf1-GTP, together with biochemical analyses, shows that Arf1 activates cargo binding by unlocking AP-1. Unlocking is driven by two molecules of Arf1 that bridge two copies of AP-1 at two interaction sites. The GTP-dependent switch I and II regions of Arf1 bind to the N terminus of the β1 subunit of one AP-1 complex, while the back side of Arf1 binds to the central part of the γ subunit trunk of a second AP-1 complex. A third Arf1 interaction site near the N terminus of the γ subunit is important for recruitment, but not activation. These observations lead to a model for the recruitment and activation of AP-1 by Arf1.

  6. TLR4 signaling mediates AP-1 activation in an MPTP-induced mouse model of Parkinson's disease.

    PubMed

    Zhao, Xu-Dong; Wang, Fa-Xiang; Cao, Wen-Fu; Zhang, Yong-Hong; Li, Yan

    2016-03-01

    To evaluate the effects of Toll-like receptor 4 (TLR4) signaling on the activation of the transcription factor activator protein-1 (AP-1) in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of Parkinson's disease (PD). The following groups were evaluated: normal saline (NS)-treated WT mice, NS-treated TLR4-knockout (KO) mice, MPTP-treated WT mice, and MPTP-treated TLR4-KO mice. After establishing the mouse model, behavioral changes were evaluated. AP-1 expression was detected by RT-PCR, Western blotting, immunohistochemistry and immunofluorescence staining. Compared to MPTP-treated WT mice, significantly reduced dyskinesia was observed in MPTP-treated TLR4-KO mice. AP-1 mRNA and protein levels were significantly up-regulated in the substantia nigras (SNs) of MPTP-treated WT mice relative to NS-treated mice (P<0.01); these levels were significantly reduced in MPTP-treated TLR4-KO mice relative to MPTP-treated WT mice (P<0.01). Immunohistochemical staining demonstrated that AP-1 was distributed throughout the SN in MPTP-treated mice, and immunofluorescence further showed that AP-1 was expressed in TH-positive neuronal cells and GFAP-positive astrocytes. In addition, immunofluorescence revealed that AP-1 expression was lower in TH-positive neurons and GFAP-positive astrocytes in the SNs of MPTP-treated TLR4-KO mice relative to MPTP-treated WT mice. The TLR4 pathway may play an important role in regulating AP-1 activation. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Isolation of NF-E2-related factor 2 (Nrf2), a NF-E2-like basic leucine zipper transcriptional activator that binds to the tandem NF-E2/AP1 repeat of the beta-globin locus control region.

    PubMed Central

    Moi, P; Chan, K; Asunis, I; Cao, A; Kan, Y W

    1994-01-01

    Hypersensitive site 2 located in the beta-globin locus control region confers high levels of expression to the genes of the beta-globin cluster. A tandem repeat of the consensus sequence for the transcription factors AP1 and NF-E2 (activating protein 1 and nuclear factor erythroid 2, respectively) is present within hypersensitive site 2 and is absolutely required for strong enhancer activity. This sequence binds, in vitro and in vivo, to ubiquitous proteins of the AP1 family and to the recently cloned erythroid-specific transcription factor NF-E2. Using the tandem repeat as a recognition site probe to screen a lambda gt11 cDNA expression library from K562 cells, we isolated several DNA binding proteins. Here, we report the characterization of one of the clones isolated. The gene, which we named Nrf2 (NF-E2-related factor 2), is encoded within a 2.2-kb transcript and predicts a 66-kDa protein with a basic leucine zipper DNA binding domain highly homologous to that of NF-E2. Although Nrf2 is expressed ubiquitously, a role of this protein in mediating enhancer activity of hypersensitive site 2 in erythroid cells cannot be excluded. In this respect, Nrf2 contains a powerful acidic activation domain that may participate in the transcriptional stimulation of beta-globin genes. Images PMID:7937919

  8. Pseudoephedrine inhibits T-cell activation by targeting NF-κB, NFAT and AP-1 signaling pathways.

    PubMed

    Fiebich, Bernd L; Collado, Juan A; Stratz, Cristian; Valina, Christian; Hochholzer, Willibald; Muñoz, Eduardo; Bellido, Luz M

    2012-02-01

    Pseudoephedrine (PSE) is a stereoisomer of ephedrine that is commonly used as a nasal decongestant in combination with other anti-inflammatory drugs for the symptomatic treatment of some common pathologies such as common cold. Herein, we describe for the first time the effects of PSE on T-cell activation events. We found that PSE inhibits interleukin-2 (IL-2) and tumor necrosis factor (TNF) alpha-gene transcription in stimulated Jurkat cells, a human T-cell leukemia cell line. To further characterize the inhibitory mechanisms of PSE at the transcriptional level, we examined the transcriptional activities of nuclear factor kappa B (NF-κB), nuclear factor of activated T cells (NFAT), and activator protein-1 (AP-1) transcription factors and found that PSE inhibited NF-κB-dependent transcriptional activity without affecting either the phosphorylation, the degradation of the cytoplasmic NF-κB inhibitory protein, IκBα or the DNA-binding activity. However, phosphorylation of the p65/RelA subunit was clearly inhibited by PSE in stimulated cells. In addition, PSE inhibited the transcriptional activity of NFAT without interfering with the calcium-induced NFAT dephosphorylation event, which represents the major signaling pathway for its activation. NFAT cooperates with c-Jun, a compound of the AP-1 complex, to activate target genes, and we also found that PSE inhibited both JNK activation and AP-1 transcriptional activity. These findings provide new mechanistic insights into the potential immunomodulatory activities of PSE and highlight their potential in designing novel therapeutic strategies to manage inflammatory diseases.

  9. Stimulation of Pol III-dependent 5S rRNA and U6 snRNA gene expression by AP-1 transcription factors.

    PubMed

    Ahuja, Richa; Kumar, Vijay

    2017-07-01

    RNA polymerase III transcribes structurally diverse group of essential noncoding RNAs including 5S ribosomal RNA (5SrRNA) and U6 snRNA. These noncoding RNAs are involved in RNA processing and ribosome biogenesis, thus, coupling Pol III activity to the rate of protein synthesis, cell growth, and proliferation. Even though a few Pol II-associated transcription factors have been reported to participate in Pol III-dependent transcription, its activation by activator protein 1 (AP-1) factors, c-Fos and c-Jun, has remained unexplored. Here, we show that c-Fos and c-Jun bind to specific sites in the regulatory regions of 5S rRNA (type I) and U6 snRNA (type III) gene promoters and stimulate their transcription. Our chromatin immunoprecipitation studies suggested that endogenous AP-1 factors bind to their cognate promoter elements during the G1/S transition of cell cycle apparently synchronous with Pol III transcriptional activity. Furthermore, the interaction of c-Jun with histone acetyltransferase p300 promoted the recruitment of p300/CBP complex on the promoters and facilitated the occupancy of Pol III transcriptional machinery via histone acetylation and chromatin remodeling. The findings of our study, together, suggest that AP-1 factors are novel regulators of Pol III-driven 5S rRNA and U6 snRNA expression with a potential role in cell proliferation. © 2017 Federation of European Biochemical Societies.

  10. Pro/antioxidant status and AP-1 transcription factor in murine skin following topical exposure to cumene hydroperoxide.

    PubMed

    Murray, A R; Kisin, E R; Kommineni, C; Vallyathan, V; Castranova, V; Shvedova, A A

    2007-07-01

    Organic peroxides, widely used in the chemical and pharmaceutical industries, can act as skin tumor promoters and cause epidermal hyperplasia. They are also known to trigger free radical generation. The present study evaluated the effect of cumene hydroperoxide (Cum-OOH) on the induction of activator protein-1 (AP-1), which is linked to the expression of genes regulating cell proliferation, growth and transformation. Previously, we reported that topical exposure to Cum-OOH caused formation of free radicals and oxidative stress in the skin of vitamin E-deficient mice. The present study used JB6 P+ mouse epidermal cells and AP-1-luciferase reporter transgenic mice to identify whether exposure to Cum-OOH caused activation of AP-1, oxidative stress, depletion of antioxidants and tumor formation during two-stage carcinogenesis. In vitro studies found that exposure to Cum-OOH reduced the level of glutathione (GSH) in mouse epidermal cells (JB6 P+) and caused the induction of AP-1. Mice primed with dimethyl-benz[a]anthracene (DMBA) were topically exposed to Cum-OOH (82.6 micromol) or the positive control, 12-O-tetradecanoylphorbol-13-acetate (TPA, 17 nmol), twice weekly for 29 weeks. Activation of AP-1 in skin was detected as early as 2 weeks following Cum-OOH or TPA exposure. No AP-1 expression was found 19 weeks after initiation. Papilloma formation was observed in both the DMBA-TPA- and DMBA-Cum-OOH-exposed animals, whereas skin carcinomas were found only in the DMBA-Cum-OOH-treated mice. A greater accumulation of peroxidative products (thiobarbituric acid-reactive substances), inflammation and decreased levels of GSH and total antioxidant reserves were also observed in the skin of DMBA-Cum-OOH-exposed mice. These results suggest that Cum-OOH-induced carcinogenesis is accompanied by increased AP-1 activation and changes in antioxidant status.

  11. Glucocorticoid receptor-mediated suppression of the interleukin 2 gene expression through impairment of the cooperativity between nuclear factor of activated T cells and AP-1 enhancer elements

    PubMed Central

    1992-01-01

    The immunosuppressant hormone dexamethasone (Dex) interferes with T cell-specific signals activating the enhancer sequences directing interleukin 2 (IL-2) transcription. We report that the Dex-dependent downregulation of 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and calcium ionophore-induced activity of the IL-2 enhancer are mediated by glucocorticoid receptor (GR) via a process that requires intact NH2- and COOH-terminal and DNA-binding domains. Functional analysis of chloramphenicol acetyltransferase (CAT) vectors containing internal deletions of the -317 to +47 bp IL-2 enhancer showed that the GR- responsive elements mapped to regions containing nuclear factor of activated T cells protein (NFAT) (-279 to -263 bp) and AP-1 (-160 to - 150 bp) motifs. The AP-1 motif binds TPA and calcium ionophore-induced nuclear factor(s) containing fos protein. TPA and calcium ionophore- induced transcriptional activation of homo-oligomers of the NFAT element were not inhibited by Dex, while AP-1 motif concatemers were not stimulated by TPA and calcium ionophore. When combined, NFAT and AP- 1 motifs significantly synergized in directing CAT transcription. Such a synergism was impaired by specific mutations affecting the trans- acting factor binding to either NFAT or AP-1 motifs. In spite of the lack of hormone regulation of isolated cis elements, TPA/calcium ionophore-mediated activation of CAT vectors containing a combination of the NFAT and the AP-1 motifs became suppressible by Dex. Our results show that the IL-2-AP-1 motif confers GR sensitivity to a flanking region containing a NFAT element and suggest that synergistic cooperativity between the NFAT and AP-1 sites allows GR to mediate the Dex inhibition of IL-2 gene transcription. Therefore, a Dex-modulated second level of IL-2 enhancer regulation, based on a combinatorial modular interplay, appears to be present. PMID:1740658

  12. Epicatechin induces NF-kappaB, activator protein-1 (AP-1) and nuclear transcription factor erythroid 2p45-related factor-2 (Nrf2) via phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) and extracellular regulated kinase (ERK) signalling in HepG2 cells.

    PubMed

    Granado-Serrano, Ana Belén; Martín, María Angeles; Haegeman, Guy; Goya, Luis; Bravo, Laura; Ramos, Sonia

    2010-01-01

    The dietary flavonoid epicatechin has been reported to exhibit a wide range of biological activities. The objective of the present study was to investigate the time-dependent regulation by epicatechin on the activity of the main transcription factors (NF-kappaB, activator protein-1 (AP-1) and nuclear transcription factor erythroid 2p45-related factor (Nrf2)) related to antioxidant defence and survival and proliferation pathways in HepG2 cells. Treatment of cells with 10 microm-epicatechin induced the NF-kappaB pathway in a time-dependent manner characterised by increased levels of IkappaB kinase (IKK) and phosphorylated inhibitor of kappaB subunit-alpha (p-IkappaBalpha) and proteolytic degradation of IkappaB, which was consistent with an up-regulation of the NF-kappaB-binding activity. Time-dependent activation of the AP-1 pathway, in concert with enhanced c-Jun nuclear levels and induction of Nrf2 translocation and phosphorylation were also demonstrated. Additionally, epicatechin-induced NF-kappaB and Nrf2 were connected to reactive oxygen species intracellular levels and to the activation of cell survival and proliferation pathways, being phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) and extracellular regulated kinase (ERK) associated to Nrf2 modulation and ERK to NF-kappaB induction. These data suggest that the epicatechin-induced survival effect occurs by the induction of redox-sensitive transcription factors through a tight regulation of survival and proliferation pathways.

  13. Purinergic P2Y2 Receptor Control of Tissue Factor Transcription in Human Coronary Artery Endothelial Cells: NEW AP-1 TRANSCRIPTION FACTOR SITE AND NEGATIVE REGULATOR.

    PubMed

    Liu, Yiwei; Zhang, Lingxin; Wang, Chuan; Roy, Shama; Shen, Jianzhong

    2016-01-22

    We recently reported that the P2Y2 receptor (P2Y2R) is the predominant nucleotide receptor expressed in human coronary artery endothelial cells (HCAEC) and that P2Y2R activation by ATP or UTP induces dramatic up-regulation of tissue factor (TF), a key initiator of the coagulation cascade. However, the molecular mechanism of this P2Y2R-TF axis remains unclear. Here, we report the role of a newly identified AP-1 consensus sequence in the TF gene promoter and its original binding components in P2Y2R regulation of TF transcription. Using bioinformatics tools, we found that a novel AP-1 site at -1363 bp of the human TF promoter region is highly conserved across multiple species. Activation of P2Y2R increased TF promoter activity and mRNA expression in HCAEC. Truncation, deletion, and mutation of this distal AP-1 site all significantly suppressed TF promoter activity in response to P2Y2R activation. EMSA and ChIP assays further confirmed that upon P2Y2R activation, c-Jun, ATF-2, and Fra-1, but not the typical c-Fos, bound to the new AP-1 site. In addition, loss-of-function studies using siRNAs confirmed a positive transactivation role of c-Jun and ATF-2 but unexpectedly revealed a strong negative role of Fra-1 in P2Y2R-induced TF up-regulation. Furthermore, we found that P2Y2R activation promoted ERK1/2 phosphorylation through Src, leading to Fra-1 activation, whereas Rho/JNK mediated P2Y2R-induced activation of c-Jun and ATF-2. These findings reveal the molecular basis for P2Y G protein-coupled receptor control of endothelial TF expression and indicate that targeting the P2Y2R-Fra-1-TF pathway may be an attractive new strategy for controlling vascular inflammation and thrombogenicity associated with endothelial dysfunction. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. AP-1-mediated chromatin looping regulates ZEB2 transcription: new insights into TNFα-induced epithelial-mesenchymal transition in triple-negative breast cancer.

    PubMed

    Qiao, Yichun; Shiue, Chiou-Nan; Zhu, Jian; Zhuang, Ting; Jonsson, Philip; Wright, Anthony P H; Zhao, Chunyan; Dahlman-Wright, Karin

    2015-04-10

    The molecular determinants of malignant cell behaviour in triple-negative breast cancer (TNBC) are poorly understood. Recent studies have shown that regulators of epithelial-mesenchymal transition (EMT) are potential therapeutic targets for TNBC. In this study, we demonstrate that the inflammatory cytokine TNFα induces EMT in TNBC cells via activation of AP-1 signaling and subsequently induces expression of the EMT regulator ZEB2. We also show that TNFα activates both the PI3K/Akt and MAPK/ERK pathways, which act upstream of AP-1. We further investigated in detail AP-1 regulation of ZEB2 expression. We show that two ZEB2 transcripts derived from distinct promoters are both expressed in breast cancer cell lines and breast tumor samples. Using the chromosome conformation capture assay, we demonstrate that AP-1, when activated by TNFα, binds to a site in promoter 1b of the ZEB2 gene where it regulates the expression of both promoter 1b and 1a, the latter via mediating long range chromatin interactions. Overall, this work provides a plausible mechanism for inflammation-induced metastatic potential in TNBC, involving a novel regulatory mechanism governing ZEB2 isoform expression.

  15. AP-1-mediated chromatin looping regulates ZEB2 transcription: new insights into TNFα-induced epithelial–mesenchymal transition in triple-negative breast cancer

    PubMed Central

    Qiao, Yichun; Shiue, Chiou-Nan; Zhu, Jian; Zhuang, Ting; Jonsson, Philip; Wright, Anthony P.H.; Zhao, Chunyan; Dahlman-Wright, Karin

    2015-01-01

    The molecular determinants of malignant cell behaviour in triple-negative breast cancer (TNBC) are poorly understood. Recent studies have shown that regulators of epithelial-mesenchymal transition (EMT) are potential therapeutic targets for TNBC. In this study, we demonstrate that the inflammatory cytokine TNFα induces EMT in TNBC cells via activation of AP-1 signaling and subsequently induces expression of the EMT regulator ZEB2. We also show that TNFα activates both the PI3K/Akt and MAPK/ERK pathways, which act upstream of AP-1. We further investigated in detail AP-1 regulation of ZEB2 expression. We show that two ZEB2 transcripts derived from distinct promoters are both expressed in breast cancer cell lines and breast tumor samples. Using the chromosome conformation capture assay, we demonstrate that AP-1, when activated by TNFα, binds to a site in promoter 1b of the ZEB2 gene where it regulates the expression of both promoter 1b and 1a, the latter via mediating long range chromatin interactions. Overall, this work provides a plausible mechanism for inflammation-induced metastatic potential in TNBC, involving a novel regulatory mechanism governing ZEB2 isoform expression. PMID:25762639

  16. Methyl-dependent and spatial-specific DNA recognition by the orthologous transcription factors human AP-1 and Epstein-Barr virus Zta

    PubMed Central

    Hong, Samuel; Wang, Dongxue; Horton, John R.; Zhang, Xing; Speck, Samuel H.; Blumenthal, Robert M.

    2017-01-01

    Abstract Activator protein 1 (AP-1) is a transcription factor that recognizes two versions of a 7-base pair response element, either 5΄-TGAGTCA-3΄ or 5΄-MGAGTCA-3΄ (where M = 5-methylcytosine). These two elements share the feature that 5-methylcytosine and thymine both have a methyl group in the same position, 5-carbon of the pyrimidine, so each of them has two methyl groups at nucleotide positions 1 and 5 from the 5΄ end, resulting in four methyl groups symmetrically positioned in duplex DNA. Epstein-Barr Virus Zta is a key transcriptional regulator of the viral lytic cycle that is homologous to AP-1. Zta recognizes several methylated Zta-response elements, including meZRE1 (5΄-TGAGMCA-3΄) and meZRE2 (5΄-TGAGMGA-3΄), where a methylated cytosine occupies one of the inner thymine residues corresponding to the AP-1 element, resulting in the four spatially equivalent methyl groups. Here, we study how AP-1 and Zta recognize these methyl groups within their cognate response elements. These methyl groups are in van der Waals contact with a conserved di-alanine in AP-1 dimer (Ala265 and Ala266 in Jun), or with the corresponding Zta residues Ala185 and Ser186 (via its side chain carbon Cβ atom). Furthermore, the two ZRE elements differ at base pair 6 (C:G versus G:C), forming a pseudo-symmetric sequence (meZRE1) or an asymmetric sequence (meZRE2). In vitro DNA binding assays suggest that Zta has high affinity for all four sequences examined, whereas AP-1 has considerably reduced affinity for the asymmetric sequence (meZRE2). We ascribe this difference to Zta Ser186 (a unique residue for Zta) whose side chain hydroxyl oxygen atom interacts with the two half sites differently, whereas the corresponding Ala266 of AP-1 Jun protein lacks such flexibility. Our analyses demonstrate a novel mechanism of 5mC/T recognition in a methylation-dependent, spatial and sequence-specific approach by basic leucine-zipper transcriptional factors. PMID:28158710

  17. AP-1/IRF-3 Targeted Anti-Inflammatory Activity of Andrographolide Isolated from Andrographis paniculata

    PubMed Central

    Shen, Ting; Yang, Woo Seok; Sung, Gi-Ho; Rhee, Man Hee; Poo, Haryoung; Kim, Mi-Yeon; Kim, Kyung-Woon; Kim, Jong Heon; Cho, Jae Youl

    2013-01-01

    Andrographolide (AG) is an abundant component of plants of the genus Andrographis and has a number of beneficial properties including neuroprotective, anticancer, anti-inflammatory, and antidiabetic effects. Despite numerous pharmacological studies, the precise mechanism of AG is still ambiguous. Thus, in the present study, we investigated the molecular mechanisms of AG and its target proteins as they pertain to anti-inflammatory responses. AG suppressed the production of nitric oxide (NO) and prostaglandin E2 (PGE2), as well as the mRNA abundance of inducible NO synthase (iNOS), tumor necrosis factor-alpha (TNF-α), cyclooxygenase (COX)-2, and interferon-beta (IFN-β) in a dose-dependent manner in both lipopolysaccharide- (LPS-) activated RAW264.7 cells and peritoneal macrophages. AG also substantially ameliorated the symptoms of LPS-induced hepatitis and EtOH/HCl-induced gastritis in mice. Based on the results of luciferase reporter gene assays, kinase assays, and measurement of nuclear levels of transcription factors, the anti-inflammatory effects of AG were found to be clearly mediated by inhibition of both (1) extracellular signal-regulated kinase (ERK)/activator protein (AP)-1 and (2) IκB kinase ε (IKKε)/interferon regulatory factor (IRF)-3 pathways. In conclusion, we detected a novel molecular signaling pathway by which AG can suppress inflammatory responses. Thus, AG is a promising anti-inflammatory drug with two pharmacological targets. PMID:23840248

  18. NFκB- and AP-1-mediated DNA looping regulates matrix metalloproteinase-9 transcription in TNF-α-treated human leukemia U937 cells.

    PubMed

    Chen, Ying-Jung; Chang, Long-Sen

    2015-10-01

    The aim of this study is to explore the spatial association of critical genomic elements in the effect of TNF-α on matrix metalloproteinase-9 (MMP-9) expression in human leukemia U937 cells. TNF-α up-regulated MMP-9 protein expression and mRNA level in U937 cells, and Akt-mediated-NFκB/p65 activation and JNK-mediated c-Jun activation were proven to be involved in TNF-α-induced MMP-9 up-regulation. Promoter luciferase activity assay revealed that NFκB (nt-600) and AP-1 (nt-79) binding sites were crucial for TNF-α-induced transcription of MMP-9 gene. The results of a chromatin immunoprecipitation assay indicated that TNF-α reduced histone deacetylase-1 (HDAC-1) recruitment but increased p300 (a histone acetyltransferase) recruitment to MMP-9 promoter regions surrounding NFκB and AP-1 binding sites. Consistently, TNF-α increased enrichment of the acetylated histone H3 mark on MMP-9 promoter regions. DNA affinity purification assay revealed that p300 and HDAC1 could bind oligonucleotides containing AP-1/c-Jun and NFκB/p65 binding sites. Chromosome conformation capture assay showed that TNF-α stimulated chromosomal loops in the MMP-9 promoter via NFκB/p65 and AP-1/c-Jun. The p300-associated acetyltransferase activity was crucial for p65/c-Jun-mediated DNA looping, and inhibition of HDAC activity increased the level of DNA looping. Reduction in the level of DNA looping eliminated all TNF-α-stimulated MMP-9 up-regulation. Taken together, our data suggest that p65/c-Jun-mediated DNA looping is involved in TNF-α-induced MMP-9 up-regulation and that the recruitment of p300 or HDAC1 to NFκB and AP-1 binding sites modifies the level of DNA looping.

  19. Redox Regulation of an AP-1-Like Transcription Factor, YapA, in the Fungal Symbiont Epichloë festucae

    PubMed Central

    Cartwright, Gemma M.

    2013-01-01

    One of the central regulators of oxidative stress in Saccharomyces cerevisiae is Yap1, a bZIP transcription factor of the AP-1 family. In unstressed cells, Yap1 is reduced and cytoplasmic, but in response to oxidative stress, it becomes oxidized and accumulates in the nucleus. To date, there have been no reports on the role of AP-1-like transcription factors in symbiotic fungi. An ortholog of Yap1, named YapA, was identified in the genome of the grass symbiont Epichloë festucae and shown to complement an S. cerevisiae Δyap1 mutant. Hyphae of the E. festucae ΔyapA strain were sensitive to menadione and diamide but resistant to H2O2, KO2, and tert-butyl hydroperoxide (t-BOOH). In contrast, conidia of the ΔyapA strain were very sensitive to H2O2 and failed to germinate. Using a PcatA-eGFP degron-tagged reporter, YapA was shown to be required for expression of a spore-specific catalase gene, catA. Although YapA-EGFP localized to the nucleus in response to host reactive oxygen species during seedling infection, there was no difference in whole-plant and cellular phenotypes of plants infected with the ΔyapA strain compared to the wild-type strain. Homologs of the S. cerevisiae and Schizosaccharomyces pombe redox-sensing proteins (Gpx3 and Tpx1, respectively) did not act as redox sensors for YapA in E. festucae. In response to oxidative stress, YapA-EGFP localized to the nuclei of E. festucae ΔgpxC, ΔtpxA, and ΔgpxC ΔtpxA cells to the same degree as that in wild-type cells. These results show that E. festucae has a robust system for countering oxidative stress in culture and in planta but that Gpx3- or Tpx1-like thiol peroxidases are dispensable for activation of YapA. PMID:23893078

  20. Redox regulation of an AP-1-like transcription factor, YapA, in the fungal symbiont Epichloe festucae.

    PubMed

    Cartwright, Gemma M; Scott, Barry

    2013-10-01

    One of the central regulators of oxidative stress in Saccharomyces cerevisiae is Yap1, a bZIP transcription factor of the AP-1 family. In unstressed cells, Yap1 is reduced and cytoplasmic, but in response to oxidative stress, it becomes oxidized and accumulates in the nucleus. To date, there have been no reports on the role of AP-1-like transcription factors in symbiotic fungi. An ortholog of Yap1, named YapA, was identified in the genome of the grass symbiont Epichloë festucae and shown to complement an S. cerevisiae Δyap1 mutant. Hyphae of the E. festucae ΔyapA strain were sensitive to menadione and diamide but resistant to H2O2, KO2, and tert-butyl hydroperoxide (t-BOOH). In contrast, conidia of the ΔyapA strain were very sensitive to H2O2 and failed to germinate. Using a PcatA-eGFP degron-tagged reporter, YapA was shown to be required for expression of a spore-specific catalase gene, catA. Although YapA-EGFP localized to the nucleus in response to host reactive oxygen species during seedling infection, there was no difference in whole-plant and cellular phenotypes of plants infected with the ΔyapA strain compared to the wild-type strain. Homologs of the S. cerevisiae and Schizosaccharomyces pombe redox-sensing proteins (Gpx3 and Tpx1, respectively) did not act as redox sensors for YapA in E. festucae. In response to oxidative stress, YapA-EGFP localized to the nuclei of E. festucae ΔgpxC, ΔtpxA, and ΔgpxC ΔtpxA cells to the same degree as that in wild-type cells. These results show that E. festucae has a robust system for countering oxidative stress in culture and in planta but that Gpx3- or Tpx1-like thiol peroxidases are dispensable for activation of YapA.

  1. DIFFERENTIAL ACTIVATION OF AP-1 IN HUMAN BLADDER EPITHELIAL CELLS BY INORGANIC AND METHYLATED ARSENICALS

    EPA Science Inventory

    Differential Activation of AP-1 in Human Bladder Epithelial Cells by Inorganic and Methylated Arsenicals

    Zuzana Drobna, Ilona Jaspers, David J. Thomas, and Miroslav Styblo

    ABSTRACT

    Epidemiological studies have linked chronic ingestion of drinking water contai...

  2. DIFFERENTIAL ACTIVATION OF AP-1 IN HUMAN BLADDER EPITHELIAL CELLS BY INORGANIC AND METHYLATED ARSENICALS

    EPA Science Inventory

    Differential Activation of AP-1 in Human Bladder Epithelial Cells by Inorganic and Methylated Arsenicals

    Zuzana Drobna, Ilona Jaspers, David J. Thomas, and Miroslav Styblo

    ABSTRACT

    Epidemiological studies have linked chronic ingestion of drinking water contai...

  3. Structure and regulation of the versican promoter: the versican promoter is regulated by AP-1 and TCF transcription factors in invasive human melanoma cells.

    PubMed

    Domenzain-Reyna, Clelia; Hernández, Daniel; Miquel-Serra, Laia; Docampo, María José; Badenas, Celia; Fabra, Angels; Bassols, Anna

    2009-05-01

    Versican is a large chondroitin sulfate proteoglycan of the extracellular matrix that is involved in a variety of cellular processes. We showed previously that versican, which is overexpressed in cutaneous melanomas as well as in premalignant lesions, contributes to melanoma progression, favoring the detachment of cells and the metastatic dissemination. Here, we investigated the transcriptional regulation of the versican promoter in melanoma cell lines with different levels of biological aggressiveness and stages of differentiation. We show that versican promoter up-regulation accounts for the differential expression levels of mRNA and protein detected in the invasive SK-mel-131 human melanoma cells. The activity of the versican promoter increased 5-fold in these cells in comparison with that measured in non-invasive MeWo melanoma cells. Several transcriptional regulatory elements were identified in the proximal promoter, including AP-1, Sp1, AP-2, and two TCF-4 sites. We show that promoter activation is mediated by the ERK/MAPK and JNK signaling pathways acting on the AP-1 site, suggesting that BRAF mutation present in SK-mel-131 cells impinge upon the up-regulation of the versican gene through signaling elicited by the ERK/MAPK pathway. This is the first time the AP-1 transcription factor family has been shown to be related to the regulation of versican expression. Furthermore, deletion of the TCF-4 binding sites caused a 60% decrease in the promoter activity in SK-mel-131 cells. These results showing that AP-1 and TCF-4 binding sites are the main regulatory regions directing versican production provide new insights into versican promoter regulation during melanoma progression.

  4. Transcriptional regulation of the mouse CD11c promoter by AP-1 complex with JunD and Fra2 in dendritic cells.

    PubMed

    Hara, Mutsuko; Yokoyama, Hokuto; Fukuyama, Kanako; Kitamura, Nao; Shimokawa, Naomi; Maeda, Keiko; Kanada, Shunsuke; Ito, Tomonobu; Usui, Yoshihiko; Ogawa, Hideoki; Okumura, Ko; Nishiyama, Makoto; Nishiyama, Chiharu

    2013-03-01

    CD11c, a member of the β(2) integrin family of adhesion molecule, is expressed on the surface of myeloid lineages and activated lymphoid cells and forms a heterodimeric receptor with CD18. We analyzed the mouse CD11c promoter structure to elucidate the transcriptional regulation in dendritic cells (DCs). By reporter assay, the -84/-65 region was identified to be essential for activity of the mouse CD11c promoter in the mouse bone marrow-derived (BM) DCs and monocyte cell line RAW264.7. An electrophoretic mobility shift assay using a number of antibodies against transcription factors revealed that the target region was recognized by a complex including JunD and Fra2, which are transcription factors belonging to the AP-1 family. The direct interaction of JunD and Fra2 with the CD11c promoter was further confirmed by a chromatin immunoprecipitation assay using CD11c-positive cells purified from BMDCs. Finally, mouse JunD and/or Fra2 siRNA was introduced into BMDCs to evaluate the involvement of these factors against CD11c transcription and found that Fra2 siRNA reduced cell surface expression level of CD11c. These results indicate that AP-1 composed with JunD and Fra2 protein plays a primary role in enhancing the transcription level of the CD11c gene in DC. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. bZIP transcription factor CgAP1 is essential for oxidative stress tolerance and full virulence of the poplar anthracnose fungus Colletotrichum gloeosporioides.

    PubMed

    Sun, Yingjiao; Wang, Yonglin; Tian, Chengming

    2016-10-01

    Yeast AP1 transcription factor is a regulator of oxidative stress response. Here, we report the identification and characterization of CgAP1, an ortholog of YAP1 in poplar anthracnose fungus Colletotrichum gloeosporioides. The expression of CgAP1 was highly induced by reactive oxygen species. CgAP1 deletion mutants displayed enhanced sensitivity to oxidative stress compared with the wild-type strain, and their poplar leaf virulence was obviously reduced. However, the mutants exhibited no obvious defects in aerial hyphal growth, conidia production, and appressoria formation. CgAP1::eGFP fusion protein localized to the nucleus after TBH (tert-Butyl hydroperoxide) treatment, suggesting that CgAP1 functions as a redox sensor in C. gloeosporioides. In addition, CgAP1 prevented the accumulation of ROS during early stages of biotrophic growth. CgAP1 also acted as a positive regulator of several ROS-related genes (i.e., Glr1, Hyr1, and Cyt1) involved in the antioxidative response. These results highlight the key regulatory role of CgAP1 transcription factor in oxidative stress response and provide insights into the function of ROS detoxification in virulence of C. gloeosporioides. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. AP-1 mediated relief of repressive activity of the CD30 promoter microsatellite in Hodgkin and Reed-Sternberg cells.

    PubMed

    Watanabe, Mariko; Ogawa, Yuji; Ito, Kinji; Higashihara, Masaaki; Kadin, Marshall E; Abraham, Lawrence J; Watanabe, Toshiki; Horie, Ryouichi

    2003-08-01

    Overexpression of CD30 is the hallmark of Hodgkin and Reed-Sternberg (H-RS) cells and drives constitutive nuclear factor-kappaB activation that is the molecular basis for the pathophysiology of Hodgkin's lymphoma. Transcription of the CD30 gene is controlled by the core promoter that is driven by Sp-1 and the microsatellite sequences (MSs) that represses core promoter activity. To understand the mechanism(s) of CD30 overexpression in H-RS cells, we structurally and functionally characterized the CD30 MSs. Although the CD30 MS of H-RS cell lines was polymorphic, it was not truncated compared with that of control cells. A strong core promoter activity and constitutive Sp-1 binding were revealed in all cell lines examined irrespective of the levels of CD30 expression. In transient reporter gene assays, all MS clones derived from H-RS cell lines repressed the core promoter activity in unrelated cell lines, but not in the H-RS cell lines. An AP-1-binding site was found in the MS at nucleotide position of -377 to -371, the presence of which was found to relieve repression of the core promoter in H-RS cell lines but not in other tumor cell lines. H-RS cell lines showed constitutive and strong AP-1-binding activity, but other cell lines did not. The AP-1 complex contained JunB, whose overexpression activated reporter constructs driven by the CD30 promoter including the MSs, and was dependent on the AP-1 site. JunB expression was detected in H-RS cells in vitro and in vivo, but not in reactive cells or tumor cells of non-Hodgkin's lymphoma of diffuse large B-cell type. Transduction of JunB small interfering RNAs suppressed CD30 promoter activity in L428 cells but not in control cells. Taken together, overexpression and binding of JunB to the AP-1 site appear to relieve the repression of the core promoter by the CD30 MS in H-RS cells, which provide one basis for the constitutive overexpression of CD30 in Hodgkin's lymphoma.

  7. Photodynamic activation as a molecular switch to promote osteoblast cell differentiation via AP-1 activation

    PubMed Central

    Kushibiki, Toshihiro; Tu, Yupeng; Abu-Yousif, Adnan O.; Hasan, Tayyaba

    2015-01-01

    In photodynamic therapy (PDT), cells are impregnated with a photosensitizing agent that is activated by light irradiation, thereby photochemically generating reactive oxygen species (ROS). The amounts of ROS produced depends on the PDT dose and the nature of the photosensitizer. Although high levels of ROS are cytotoxic, at physiological levels they play a key role as second messengers in cellular signaling pathways, pluripotency, and differentiation of stem cells. To investigate further the use of photochemically triggered manipulation of such pathways, we exposed mouse osteoblast precursor cells and rat primary mesenchymal stromal cells to low-dose PDT. Our results demonstrate that low-dose PDT can promote osteoblast differentiation via the activation of activator protein-1 (AP-1). Although PDT has been used primarily as an anti-cancer therapy, the use of light as a photochemical “molecular switch” to promote differentiation should expand the utility of this method in basic research and clinical applications. PMID:26279470

  8. AP-1-Targeting Anti-Inflammatory Activity of the Methanolic Extract of Persicaria chinensis

    PubMed Central

    Son, Young-Jin; Baek, Kwang-Soo; Yang, Woo Seok; Park, Jae Gwang; Kim, Han Gyung; Chung, Woo-Jae; Yoon, Keejung; Lee, Sang Yeol; Kim, Jong-Hoon

    2015-01-01

    In traditional Chinese medicine, Persicaria chinensis L. has been prescribed to cure numerous inflammatory disorders. We previously analyzed the bioactivity of the methanol extract of this plant (Pc-ME) against LPS-induced NO and PGE2 in RAW264.7 macrophages and found that it prevented HCl/EtOH-induced gastric ulcers in mice. The purpose of the current study was to explore the molecular mechanism by which Pc-ME inhibits activator protein- (AP-) 1 activation pathway and mediates its hepatoprotective activity. To investigate the putative therapeutic properties of Pc-ME against AP-1-mediated inflammation and hepatotoxicity, lipopolysaccharide- (LPS-) stimulated RAW264.7 and U937 cells, a monocyte-like human cell line, and an LPS/D-galactosamine- (D-GalN-) induced acute hepatitis mouse model were employed. The expression of LPS-induced proinflammatory cytokines including interleukin- (IL-) 1β, IL-6, and tumor necrosis factor-α (TNF-α) was significantly diminished by Pc-ME. Moreover, Pc-ME reduced AP-1 activation and mitogen-activated protein kinase (MAPK) phosphorylation in both LPS-stimulated RAW264.7 cells and differentiated U937 cells. Additionally, we highlighted the hepatoprotective and curative effects of Pc-ME pretreated orally in a mouse model of LPS/D-GalN-intoxicated acute liver injury by demonstrating the significant reduction in elevated serum AST and ALT levels and histological damage. Therefore, these results strongly suggest that Pc-ME could function as an antihepatitis remedy suppressing MAPK/AP-1-mediated inflammatory events. PMID:25878717

  9. The AP-1 Transcription Factor c-Jun Prevents Stress-Imposed Maladaptive Remodeling of the Heart

    PubMed Central

    Windak, Renata; Müller, Julius; Felley, Allison; Akhmedov, Alexander; Wagner, Erwin F.; Pedrazzini, Thierry; Sumara, Grzegorz; Ricci, Romeo

    2013-01-01

    Systemic hypertension increases cardiac workload and subsequently induces signaling networks in heart that underlie myocyte growth (hypertrophic response) through expansion of sarcomeres with the aim to increase contractility. However, conditions of increased workload can induce both adaptive and maladaptive growth of heart muscle. Previous studies implicate two members of the AP-1 transcription factor family, junD and fra-1, in regulation of heart growth during hypertrophic response. In this study, we investigate the function of the AP-1 transcription factors, c-jun and c-fos, in heart growth. Using pressure overload-induced cardiac hypertrophy in mice and targeted deletion of Jun or Fos in cardiomyocytes, we show that c-jun is required for adaptive cardiac hypertrophy, while c-fos is dispensable in this context. c-jun promotes expression of sarcomere proteins and suppresses expression of extracellular matrix proteins. Capacity of cardiac muscle to contract depends on organization of principal thick and thin filaments, myosin and actin, within the sarcomere. In line with decreased expression of sarcomere-associated proteins, Jun-deficient cardiomyocytes present disarrangement of filaments in sarcomeres and actin cytoskeleton disorganization. Moreover, Jun-deficient hearts subjected to pressure overload display pronounced fibrosis and increased myocyte apoptosis finally resulting in dilated cardiomyopathy. In conclusion, c-jun but not c-fos is required to induce a transcriptional program aimed at adapting heart growth upon increased workload. PMID:24039904

  10. Resveratrol inhibits BK-induced COX-2 transcription by suppressing acetylation of AP-1 and NF-κB in human rheumatoid arthritis synovial fibroblasts.

    PubMed

    Yang, Chuen-Mao; Chen, Yu-Wen; Chi, Pei-Ling; Lin, Chih-Chung; Hsiao, Li-Der

    2017-05-15

    Bradykinin (BK) induces inflammation in rheumatoid arthritis (RA). Resveratrol is a potent activator of Sirt1 which could modulate inflammation through deacetylating histones of transcription factors. Here, we investigated the mechanisms underlying BK-induced COX-2 expression which is modulated by resveratrol/Sirt1 in human rheumatoid arthritis synovial fibroblasts (RASFs). We found that BK-induced COX-2 protein and mRNA expression associated with PGE2 synthesis, and promoter activity was mediated through B2R receptors, which were attenuated by selective B2R antagonist Hoe140 or transfection with B2R siRNA. BK-induced responses were mediated through PKCμ, MAPKs, AP-1 and NF-κB which were inhibited by their respective inhibitors or siRNAs. Up-regulation of Sirt1 by resveratrol suppressed the BK-induced COX-2/PGE2 production through inhibiting the interaction of AP-1 and NF-κB with COX-2 promoter in RASFs. BK-induced COX-2/PGE2 expression is mediated through a B2R-PKCμ-dependent MAPKs, AP-1, and NF-κB cascade. Resveratrol inhibited the phosphorylation and acetylation of p65, c-Jun, and Fos and reduced the binding to the COX-2 promoter, thereby attenuated the COX-2 expression. Therefore, resveratrol may be a promising therapeutic intervention for treatment of inflammatory arthritis. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Expression profiling of genes regulated by Fra-1/AP-1 transcription factor during bleomycin-induced pulmonary fibrosis

    PubMed Central

    2013-01-01

    Background The Fra-1/AP-1 transcription factor regulates the expression of genes controlling various processes including migration, invasion, and survival as well as extracellular remodeling. We recently demonstrated that loss of Fra-1 leads to exacerbated bleomycin-induced pulmonary fibrosis, accompanied by enhanced expression of various inflammatory and fibrotic genes. To better understand the molecular mechanisms by which Fra-1 confers protection during bleomycin-induced lung injury, genome-wide mRNA expression profiling was performed. Results We found that Fra-1 regulates gene expression programs that include: 1) several cytokines and chemokines involved in inflammation, 2) several genes involved in the extracellular remodeling and cell adhesion, and 3) several genes involved in programmed cell death. Conclusion Loss of Fra-1 leads to the enhanced expression of genes regulating inflammation and immune responses and decreased the expression of genes involved in apoptosis, suggesting that this transcription factor distinctly modulates early pro-fibrotic cellular responses. PMID:23758685

  12. CREB, ATF, and AP-1 transcription factors regulate IFN-gamma secretion by human T cells in response to mycobacterial antigen.

    PubMed

    Samten, Buka; Townsend, James C; Weis, Steven E; Bhoumik, Anindita; Klucar, Peter; Shams, Homayoun; Barnes, Peter F

    2008-08-01

    IFN-gamma production by T cells is pivotal for defense against many pathogens, and the proximal promoter of IFN-gamma, -73 to -48 bp upstream of the transcription start site, is essential for its expression. However, transcriptional regulation mechanisms through this promoter in primary human cells remain unclear. We studied the effects of cAMP response element binding protein/activating transcription factor (CREB/ATF) and AP-1 transcription factors on the proximal promoter of IFN-gamma in human T cells stimulated with Mycobacterium tuberculosis. Using EMSA, supershift assays, and promoter pulldown assays, we demonstrated that CREB, ATF-2, and c-Jun, but not cyclic AMP response element modulator, ATF-1, or c-Fos, bind to the proximal promoter of IFN-gamma upon stimulation, and coimmunoprecipitation indicated the possibility of interaction among these transcription factors. Chromatin immunoprecipitation confirmed the recruitment of these transcription factors to the IFN-gamma proximal promoter in live Ag-activated T cells. Inhibition of ATF-2 activity in T cells with a dominant-negative ATF-2 peptide or with small interfering RNA markedly reduced the expression of IFN-gamma and decreased the expression of CREB and c-Jun. These findings suggest that CREB, ATF-2, and c-Jun are recruited to the IFN-gamma proximal promoter and that they up-regulate IFN-gamma transcription in response to microbial Ag. Additionally, ATF-2 controls expression of CREB and c-Jun during T cell activation.

  13. Chloroquine inhibits human CD4+ T-cell activation by AP-1 signaling modulation

    PubMed Central

    Schmidt, Ralf L. J.; Jutz, Sabrina; Goldhahn, Katrin; Witzeneder, Nadine; Gerner, Marlene C.; Trapin, Doris; Greiner, Georg; Hoermann, Gregor; Steiner, Guenter; Pickl, Winfried F.; Burgmann, Heinz; Steinberger, Peter; Ratzinger, Franz; Schmetterer, Klaus G.

    2017-01-01

    Chloroquine (CQ) is widely used as an anti-inflammatory therapeutic for rheumatic diseases. Although its modes of action on the innate immune system are well described, there is still insufficient knowledge about its direct effects on the adaptive immune system. Thus, we evaluated the influence of CQ on activation parameters of human CD4+ T-cells. CQ directly suppressed proliferation, metabolic activity and cytokine secretion of T-cells following anti-CD3/anti-CD28 activation. In contrast, CQ showed no effect on up-regulation of T-cell activation markers. CQ inhibited activation of all T helper cell subsets, although IL-4 and IL-13 secretion by Th2 cells were less influenced compared to other Th-specific cytokines. Up to 10 μM, CQ did not reduce cell viability, suggesting specific suppressive effects on T-cells. These properties of CQ were fully reversible in re-stimulation experiments. Analyses of intracellular signaling showed that CQ specifically inhibited autophagic flux and additionally activation of AP-1 by reducing phosphorylation of c-JUN. This effect was mediated by inhibition of JNK catalytic activity. In summary, we characterized selective and reversible immunomodulatory effects of CQ on human CD4+ T-cells. These findings provide new insights into the biological actions of JNK/AP-1 signaling in T-cells and may help to expand the therapeutic spectrum of CQ. PMID:28169350

  14. Epstein-Barr virus-encoded EBNA1 modulates the AP-1 transcription factor pathway in nasopharyngeal carcinoma cells and enhances angiogenesis in vitro.

    PubMed

    O'Neil, John D; Owen, Thomas J; Wood, Victoria H J; Date, Kathryn L; Valentine, Robert; Chukwuma, Marilyn B; Arrand, John R; Dawson, Christopher W; Young, Lawrence S

    2008-11-01

    The Epstein-Barr virus (EBV)-encoded EBNA1 protein is expressed in all virus-associated tumours, including nasopharyngeal carcinoma (NPC), where it plays an essential role in EBV genome maintenance, replication and transcription. Previous studies suggest that EBNA1 may have additional effects relevant to oncogenesis, including enhancement of cell survival, raising the possibility that EBNA1 may influence cellular gene expression. We have recently demonstrated by gene expression microarray profiling in an NPC cell model that EBNA1 influences the expression of a range of cellular genes, including those involved in transcription, translation and cell signalling. Here, we report for the first time that EBNA1 enhances activity of the AP-1 transcription factor in NPC cells and demonstrate that this is achieved by EBNA1 binding to the promoters of c-Jun and ATF2, enhancing their expression. In addition, we demonstrate elevated expression of the AP-1 targets interleukin 8, vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1alpha in response to EBNA1 expression, which enhances microtubule formation in an in vitro angiogenesis assay. Furthermore, we confirm elevation of VEGF and the phosphorylated isoforms of c-Jun and ATF2 in NPC biopsies. These findings implicate EBNA1 in the angiogenic process and suggest that this viral protein might directly contribute to the development and aggressively metastatic nature of NPC.

  15. Costunolide inhibits interleukin-1beta expression by down-regulation of AP-1 and MAPK activity in LPS-stimulated RAW 264.7 cells.

    PubMed

    Kang, Jong Soon; Yoon, Yeo Dae; Lee, Ki Hoon; Park, Song-Kyu; Kim, Hwan Mook

    2004-01-02

    Costunolide, a sesquiterpene lactone isolated from the root of Saussurea lappa Clarke, is known to have a variety of biological activities, including anti-carcinogenic and anti-fungal activities. Here, we demonstrated the inhibitory effect of costunolide on the protein and mRNA expression of interleukin-1beta (IL-1beta) in LPS-stimulated RAW 264.7 cells. We also showed that costunolide suppressed the transcriptional activity of the IL-1beta promoter. Moreover, costunolide inhibited the activity of AP-1 transcription factor, and the phosphorylation of MAPKs, including SAPK/JNK and p38 MAP kinase. The inhibitory effect of costunolide on AP-1 activity was also confirmed by an electrophoretic mobility shift assay. Additionally, specific inhibitors of SAPK/JNK and p38 MAP kinase, SP600125 and SB203580, also suppressed LPS-induced increase in IL-1beta gene expression and AP-1 DNA binding. Taken together, these results demonstrate that costunolide inhibits IL-1beta gene expression by blocking the activation of MAPKs and DNA binding of AP-1 in LPS-stimulated RAW 264.7 cells.

  16. Inhibition of p38 MAP kinase increases okadaic acid mediated AP-1 expression and DNA binding but has no effect on TRE dependent transcription.

    PubMed

    Rosenberger, S F; Gupta, A; Bowden, G T

    1999-06-17

    By performing in vitro kinase assays we found in papilloma producing 308 mouse keratinocytes that okadaic acid elevated activities of extracellular signal-regulated kinase (ERK) 1/2, c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinases (MAPKs). This okadaic acid mediated activation of MAP kinases correlated with increased AP-1 binding to a consensus TPA responsive element (TRE) and elevated TRE dependent transcription. To determine the role of p38 MAP kinases in these processes we employed the specific p38 MAP kinase inhibitor SB 203580. Using orthophosphate labeling we showed a decrease in phosphorylation of MAPK activated protein kinase-2 (MAPKAP-K2) indicating reduced activity of p38 MAPKs utilizing this kinase as substrate. In contrast, we found that SB 203580 raised activities of ERK-1/2 and JNKs. Electrophoretic mobility shift assays revealed an increase in TRE binding activity in response to SB 203580 most likely resulting from increased expression of the major TRE binding components JunD and FosB as indicated by Western blot analyses. Increased TRE DNA binding failed to lead to increased transactivation correlating with the inability of SB 203580 to increase phosphorylation of these AP-1 proteins. These data indicate that SB 203580 sensitive p38 MAP kinases are not involved in okadaic acid mediated increases in TRE DNA binding and transactivation.

  17. CARMA1- and MyD88-dependent activation of Jun/ATF-type AP-1 complexes is a hallmark of ABC diffuse large B-cell lymphomas

    PubMed Central

    Juilland, Mélanie; Gonzalez, Montserrat; Erdmann, Tabea; Banz, Yara; Jevnikar, Zala; Hailfinger, Stephan; Tzankov, Alexandar; Grau, Michael; Lenz, Georg; Novak, Urban

    2016-01-01

    A hallmark of the diffuse large B-cell lymphoma (DLBCL) of the activated B-cell (ABC) type, a molecular subtype characterized by adverse outcome, is constitutive activation of the transcription factor nuclear factor–κB (NF-κB), which controls expression of genes promoting cellular survival and proliferation. Much less, however, is known about the role of the transcription factor activator protein-1 (AP-1) in ABC DLBCL. Here, we show that AP-1, like NF-κB, was controlled by constitutive activation of the B-cell receptor signaling component caspase recruitment domain-containing membrane-associated guanylate kinase 1 (CARMA1) and/or the Toll-like receptor signaling component myeloid differentiation primary response gene 88 (MyD88) in ABC DLBCL cell lines. In contrast to germinal center (GC) B-cell (GCB) DLBCL, ABC DLBCL cell lines expressed high levels of the AP-1 family members c-Jun, JunB, and JunD, which formed heterodimeric complexes with the AP-1 family members activating transcription factor (ATF) 2, ATF3, and ATF7. Inhibition of these complexes by a dominant-negative approach led to impaired growth of a majority of ABC DLBCL cell lines. Individual silencing of c-Jun, ATF2, or ATF3 decreased cellular survival and revealed c-Jun/ATF2-dependent control of ATF3 expression. As a consequence, ATF3 expression was much higher in ABC vs GCB DLBCL cell lines. Samples derived from DLBCL patients showed a clear trend toward high and nuclear ATF3 expression in nodal DLBCL of the non-GC or ABC subtype. These findings identify the activation of AP-1 complexes of the Jun/ATF-type as an important element controlling the growth of ABC DLBCL. PMID:26747248

  18. CARMA1- and MyD88-dependent activation of Jun/ATF-type AP-1 complexes is a hallmark of ABC diffuse large B-cell lymphomas.

    PubMed

    Juilland, Mélanie; Gonzalez, Montserrat; Erdmann, Tabea; Banz, Yara; Jevnikar, Zala; Hailfinger, Stephan; Tzankov, Alexandar; Grau, Michael; Lenz, Georg; Novak, Urban; Thome, Margot

    2016-04-07

    A hallmark of the diffuse large B-cell lymphoma (DLBCL) of the activated B-cell (ABC) type, a molecular subtype characterized by adverse outcome, is constitutive activation of the transcription factor nuclear factor-κB (NF-κB), which controls expression of genes promoting cellular survival and proliferation. Much less, however, is known about the role of the transcription factor activator protein-1 (AP-1) in ABC DLBCL. Here, we show that AP-1, like NF-κB, was controlled by constitutive activation of the B-cell receptor signaling component caspase recruitment domain-containing membrane-associated guanylate kinase 1 (CARMA1) and/or the Toll-like receptor signaling component myeloid differentiation primary response gene 88 (MyD88) in ABC DLBCL cell lines. In contrast to germinal center (GC) B-cell (GCB) DLBCL, ABC DLBCL cell lines expressed high levels of the AP-1 family members c-Jun, JunB, and JunD, which formed heterodimeric complexes with the AP-1 family members activating transcription factor (ATF) 2, ATF3, and ATF7. Inhibition of these complexes by a dominant-negative approach led to impaired growth of a majority of ABC DLBCL cell lines. Individual silencing of c-Jun, ATF2, or ATF3 decreased cellular survival and revealed c-Jun/ATF2-dependent control of ATF3 expression. As a consequence, ATF3 expression was much higher in ABC vs GCB DLBCL cell lines. Samples derived from DLBCL patients showed a clear trend toward high and nuclear ATF3 expression in nodal DLBCL of the non-GC or ABC subtype. These findings identify the activation of AP-1 complexes of the Jun/ATF-type as an important element controlling the growth of ABC DLBCL.

  19. The bZIP Transcription Factor MoAP1 Mediates the Oxidative Stress Response and Is Critical for Pathogenicity of the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Guo, Min; Chen, Yue; Du, Yan; Dong, Yanhan; Guo, Wang; Zhai, Su; Zhang, Haifeng; Dong, Suomeng; Zhang, Zhengguang; Wang, Yuanchao; Wang, Ping; Zheng, Xiaobo

    2011-01-01

    Saccharomyces cerevisiae Yap1 protein is an AP1-like transcription factor involved in the regulation of the oxidative stress response. An ortholog of Yap1, MoAP1, was recently identified from the rice blast fungus Magnaporthe oryzae genome. We found that MoAP1 is highly expressed in conidia and during invasive hyphal growth. The Moap1 mutant was sensitive to H2O2, similar to S. cerevisiae yap1 mutants, and MoAP1 complemented Yap1 function in resistance to H2O2, albeit partially. The Moap1 mutant also exhibited various defects in aerial hyphal growth, mycelial branching, conidia formation, the production of extracellular peroxidases and laccases, and melanin pigmentation. Consequently, the Moap1 mutant was unable to infect the host plant. The MoAP1-eGFP fusion protein is localized inside the nucleus upon exposure to H2O2, suggesting that MoAP1 also functions as a redox sensor. Moreover, through RNA sequence analysis, many MoAP1-regulated genes were identified, including several novel ones that were also involved in pathogenicity. Disruption of respective MGG_01662 (MoAAT) and MGG_02531 (encoding hypothetical protein) genes did not result in any detectable changes in conidial germination and appressorium formation but reduced pathogenicity, whereas the mutant strains of MGG_01230 (MoSSADH) and MGG_15157 (MoACT) showed marketed reductions in aerial hyphal growth, mycelial branching, and loss of conidiation as well as pathogenicity, similar to the Moap1 mutant. Taken together, our studies identify MoAP1 as a positive transcription factor that regulates transcriptions of MGG_01662, MGG_02531, MGG_01230, and MGG_15157 that are important in the growth, development, and pathogenicity of M. oryzae. PMID:21383978

  20. MAPK/AP-1-Targeted Anti-Inflammatory Activities of Xanthium strumarium.

    PubMed

    Hossen, Muhammad Jahangir; Kim, Mi-Yeon; Cho, Jae Youl

    2016-01-01

    Xanthium strumarium L. (Asteraceae), a traditional Chinese medicine, is prescribed to treat arthritis, bronchitis, and rhinitis. Although the plant has been used for many years, the mechanism by which it ameliorates various inflammatory diseases is not yet fully understood. To explore the anti-inflammatory mechanism of methanol extracts of X. strumarium (Xs-ME) and its therapeutic potential, we used lipopolysaccharide (LPS)-stimulated murine macrophage-like RAW264.7 cells and human monocyte-like U937 cells as well as a LPS/D-galactosamine (GalN)-induced acute hepatitis mouse model. To find the target inflammatory pathway, we used holistic immunoblotting analysis, reporter gene assays, and mRNA analysis. Xs-ME significantly suppressed the up-regulation of both the activator protein (AP)-1-mediated luciferase activity and the production of LPS-induced proinflammatory cytokines, including interleukin (IL)-1[Formula: see text], IL-6, and tumor necrosis factor (TNF)-[Formula: see text]. Moreover, Xs-ME strongly inhibited the phosphorylation of mitogen-activated protein kinase (MAPK) in LPS-stimulated RAW264.7 and U937 cells. Additionally, these results highlighted the hepatoprotective and curative effects of Xs-ME in a mouse model of LPS/D-GalN-induced acute liver injury, as assessed by elevated serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and histological damage. Therefore, our results strongly suggest that the ethnopharmacological roles of Xs-ME in hepatitis and other inflammatory diseases might result from its inhibitory activities on the inflammatory signaling of MAPK and AP-1.

  1. Activator protein-1 (AP-1) signalling in human atherosclerosis: results of a systematic evaluation and intervention study.

    PubMed

    Meijer, C Arnoud; Le Haen, Pum A A; van Dijk, Rogier A; Hira, Mitsuhisa; Hamming, Jaap F; van Bockel, J Hajo; Lindeman, Jan H

    2012-05-01

    Animal studies implicate the AP-1 (activator protein-1) pro-inflammatory pathway as a promising target in the treatment of atherosclerotic disease. It is, however, unclear whether these observations apply to human atherosclerosis. Therefore we evaluated the profile of AP-1 activation through histological analysis and tested the potential benefit of AP-1 inhibition in a clinical trial. AP-1 activation was quantified by phospho-c-Jun nuclear translocation (immunohistochemistry) on a biobank of aortic wall samples from organ donors. The effect of AP-1 inhibition on vascular parameters was tested through a double blind placebo-controlled cross-over study of 28 days doxycycline or placebo in patients with symptomatic peripheral artery disease. Vascular function was assessed by brachial dilation as well as by plasma samples analysed for hs-CRP (high-sensitivity C-reactive protein), IL-6 (interleukin-6), IL-8, ICAM-1 (intercellular adhesion molecule-1), vWF (von Willebrand factor), MCP-1 (monocyte chemoattractant protein-1), PAI-1 (plasminogen activator inhibitor-1) and fibrinogen. Histological evaluation of human atherosclerosis showed minimal AP-1 activation in non-diseased arterial wall (i.e. vessel wall without any signs of atherosclerotic disease). A gradual increase of AP-1 activation was found in non-progressive and progressive phases of atherosclerosis respectively (P<0.044). No significant difference was found between progressive and vulnerable lesions. The expression of phospho-c-Jun diminished as the lesion stabilized (P<0.016) and does not significantly differ from the normal aortic wall (P<0.33). Evaluation of the doxycycline intervention only revealed a borderline-significant reduction of circulating hs-CRP levels (-0.51 μg/ml, P=0.05) and did not affect any of the other markers of systemic inflammation and vascular function. Our studies do not characterize AP-1 as a therapeutic target for progressive human atherosclerotic disease.

  2. Interleukin-35 Inhibits Endothelial Cell Activation by Suppressing MAPK-AP-1 Pathway.

    PubMed

    Sha, Xiaojin; Meng, Shu; Li, Xinyuan; Xi, Hang; Maddaloni, Massimo; Pascual, David W; Shan, Huimin; Jiang, Xiaohua; Wang, Hong; Yang, Xiao-feng

    2015-07-31

    Vascular response is an essential pathological mechanism underlying various inflammatory diseases. This study determines whether IL-35, a novel responsive anti-inflammatory cytokine, inhibits vascular response in acute inflammation. Using a mouse model of LPS-induced acute inflammation and plasma samples from sepsis patients, we found that IL-35 was induced in the plasma of mice after LPS injection as well as in the plasma of sepsis patients. In addition, IL-35 decreased LPS-induced proinflammatory cytokines and chemokines in the plasma of mice. Furthermore, IL-35 inhibited leukocyte adhesion to the endothelium in the vessels of lung and cremaster muscle and decreased the numbers of inflammatory cells in bronchoalveolar lavage fluid. Mechanistically, IL-35 inhibited the LPS-induced up-regulation of endothelial cell (EC) adhesion molecule VCAM-1 through IL-35 receptors gp130 and IL-12Rβ2 via inhibition of the MAPK-activator protein-1 (AP-1) signaling pathway. We also found that IL-27, which shares the EBI3 subunit with IL-35, promoted LPS-induced VCAM-1 in human aortic ECs and that EBI3-deficient mice had similar vascular response to LPS when compared with that of WT mice. These results demonstrated for the first time that inflammation-induced IL-35 inhibits LPS-induced EC activation by suppressing MAPK-AP1-mediated VCAM-1 expression and attenuates LPS-induced secretion of proinflammatory cytokines/chemokines. Our results provide insight into the control of vascular inflammation by IL-35 and suggest that IL-35 is an attractive novel therapeutic reagent for sepsis and cardiovascular diseases.

  3. Fast regulation of AP-1 activity through interaction of lamin A/C, ERK1/2, and c-Fos at the nuclear envelope

    PubMed Central

    González, José María; Navarro-Puche, Ana; Casar, Berta; Crespo, Piero; Andrés, Vicente

    2008-01-01

    Sequestration of c-Fos at the nuclear envelope (NE) through interaction with A-type lamins suppresses AP-1–dependent transcription. We show here that c-Fos accumulation within the extraction-resistant nuclear fraction (ERNF) and its interaction with lamin A are reduced and enhanced by gain-of and loss-of ERK1/2 activity, respectively. Moreover, hindering ERK1/2-dependent phosphorylation of c-Fos attenuates its release from the ERNF induced by serum and promotes its interaction with lamin A. Accordingly, serum stimulation rapidly releases preexisting c-Fos from the NE via ERK1/2-dependent phosphorylation, leading to a fast activation of AP-1 before de novo c-Fos synthesis. Moreover, lamin A–null cells exhibit increased AP-1 activity and reduced levels of c-Fos phosphorylation. We also find that active ERK1/2 interacts with lamin A and colocalizes with c-Fos and A-type lamins at the NE. Thus, NE-bound ERK1/2 functions as a molecular switch for rapid mitogen-dependent AP-1 activation through phosphorylation-induced release of preexisting c-Fos from its inhibitory interaction with lamin A/C. PMID:19015316

  4. Activation of AP-1 and of a nuclear redox factor, Ref-1, in the response of HT29 colon cancer cells to hypoxia.

    PubMed Central

    Yao, K S; Xanthoudakis, S; Curran, T; O'Dwyer, P J

    1994-01-01

    Many solid tumors contain substantial fractions of hypoxic cells which are relatively resistant to both radiation therapy and certain cytotoxic drugs. We have previously shown that exposure of human HT29 cells to hypoxic conditions results in the overexpression of certain enzymes involved in the detoxication of xenobiotics, including NAD(P)H:(quinone acceptor) oxidoreductase (DT)-diaphorase, and gamma-glutamylcysteine synthetase, the rate-limiting enzyme in glutathione synthesis. This hypoxic effect on DT-diaphorase was shown to involve both transcriptional induction and altered message stability. We have investigated the effects of hypoxia on elements in the promoter region of DT-diaphorase. Electrophoretic mobility shift assays demonstrate the induction of a binding activity to the AP-1 response element of DT-diaphorase. Supershift assays suggest that this binding is due to AP-1 nuclear factors and that members of the jun family are induced to a greater degree than fos by hypoxia. Analysis of the kinetics of transcription factor expression indicates that the expression of c-jun and junD is induced during hypoxic exposure; mRNA levels fall during reoxygenation. Induction of fos on the other hand is not as florid during hypoxia (5-fold) and is most pronounced (17-fold) 24 h after the restoration of an oxic environment. Thus, the hypoxic response of DT-diaphorase expression is mediated in part through AP-1, initially by a jun-related mechanism and then by the involvement of fos. The affinity of transcription factors for the AP-1 binding site depends on the redox state of a cysteine residue located close to the DNA-binding region of both Fos and Jun. A nuclear protein, Ref-1, maintains the reduced state of Fos and Jun and promotes binding to AP-1. Nuclear extracts of HT29 cells exposed to hypoxia show markedly increased Ref-1 protein content. Elevation of ref-1 steady-state mRNA levels occurs as an early event following induction of hypoxia and persists when cells

  5. Transcriptional Network Analysis in Muscle Reveals AP-1 as a Partner of PGC-1α in the Regulation of the Hypoxic Gene Program

    PubMed Central

    Baresic, Mario; Salatino, Silvia; Kupr, Barbara

    2014-01-01

    Skeletal muscle tissue shows an extraordinary cellular plasticity, but the underlying molecular mechanisms are still poorly understood. Here, we use a combination of experimental and computational approaches to unravel the complex transcriptional network of muscle cell plasticity centered on the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a regulatory nexus in endurance training adaptation. By integrating data on genome-wide binding of PGC-1α and gene expression upon PGC-1α overexpression with comprehensive computational prediction of transcription factor binding sites (TFBSs), we uncover a hitherto-underestimated number of transcription factor partners involved in mediating PGC-1α action. In particular, principal component analysis of TFBSs at PGC-1α binding regions predicts that, besides the well-known role of the estrogen-related receptor α (ERRα), the activator protein 1 complex (AP-1) plays a major role in regulating the PGC-1α-controlled gene program of the hypoxia response. Our findings thus reveal the complex transcriptional network of muscle cell plasticity controlled by PGC-1α. PMID:24912679

  6. Transcriptional network analysis in muscle reveals AP-1 as a partner of PGC-1α in the regulation of the hypoxic gene program.

    PubMed

    Baresic, Mario; Salatino, Silvia; Kupr, Barbara; van Nimwegen, Erik; Handschin, Christoph

    2014-08-01

    Skeletal muscle tissue shows an extraordinary cellular plasticity, but the underlying molecular mechanisms are still poorly understood. Here, we use a combination of experimental and computational approaches to unravel the complex transcriptional network of muscle cell plasticity centered on the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a regulatory nexus in endurance training adaptation. By integrating data on genome-wide binding of PGC-1α and gene expression upon PGC-1α overexpression with comprehensive computational prediction of transcription factor binding sites (TFBSs), we uncover a hitherto-underestimated number of transcription factor partners involved in mediating PGC-1α action. In particular, principal component analysis of TFBSs at PGC-1α binding regions predicts that, besides the well-known role of the estrogen-related receptor α (ERRα), the activator protein 1 complex (AP-1) plays a major role in regulating the PGC-1α-controlled gene program of the hypoxia response. Our findings thus reveal the complex transcriptional network of muscle cell plasticity controlled by PGC-1α.

  7. ETV6-NTRK3 fusion oncogene initiates breast cancer from committed mammary progenitors via activation of AP1 complex

    PubMed Central

    Li, Zhe; Tognon, Cristina E.; Godinho, Frank J.; Yasaitis, Laura; Hock, Hanno; Herschkowitz, Jason I.; Lannon, Chris L.; Cho, Eunah; Kim, Seong-Jin; Bronson, Roderick T.; Perou, Charles M.; Sorensen, Poul H.; Orkin, Stuart H.

    2007-01-01

    SUMMARY To better understand the cellular origin of breast cancer, we developed a mouse model that recapitulates expression of the ETV6-NTRK3 (EN) fusion oncoprotein, the product of the t(12;15)(p13;q25) translocation characteristic of human secretory breast carcinoma. Activation of EN expression in mammary tissues by Wap-Cre leads to fully penetrant, multifocal malignant breast cancer with short latency. We provide genetic evidence that in nulliparous Wap-Cre;EN females, committed alveolar bipotent or CD61+ luminal progenitors, are targets of tumorigenesis. Furthermore, EN transforms these otherwise transient progenitors through activation of the AP1 complex. Given increasing relevance of chromosomal translocations in epithelial cancers, such mice serve as a paradigm for the study of their genetic pathogenesis and cellular origins, and generation of novel preclinical models. SIGNIFICANCE For the largest class of human tumors, those of epithelial origin, little is known about their initiating genetic hits or cells of origin. Whether tissue stem cells or more committed progenitors are targets for transformation is uncertain. We developed a system in which epithelial tumorigenesis can be assessed from the initial event to frank malignancy. In this breast cancer model based on chromosomal translocation, we show through genetic marking that committed mammary progenitors, rather than mammary stem cells, are direct targets of transformation. We show that activation of the AP1 complex represents a critical downstream event of the ETV6-NTRK3 translocation. Further focus on this transcriptional complex as a target in human breast cancer is warranted. PMID:18068631

  8. The AP-1 transcription factor component Fosl2 potentiates the rate of myocardial differentiation from the zebrafish second heart field

    PubMed Central

    Jahangiri, Leila; Sharpe, Michka; Novikov, Natasha; González-Rosa, Juan Manuel; Borikova, Asya; Nevis, Kathleen; Paffett-Lugassy, Noelle; Zhao, Long; Adams, Meghan; Guner-Ataman, Burcu; Burns, Caroline E.; Burns, C. Geoffrey

    2016-01-01

    The vertebrate heart forms through successive phases of cardiomyocyte differentiation. Initially, cardiomyocytes derived from first heart field (FHF) progenitors assemble the linear heart tube. Thereafter, second heart field (SHF) progenitors differentiate into cardiomyocytes that are accreted to the poles of the heart tube over a well-defined developmental window. Although heart tube elongation deficiencies lead to life-threatening congenital heart defects, the variables controlling the initiation, rate and duration of myocardial accretion remain obscure. Here, we demonstrate that the AP-1 transcription factor, Fos-like antigen 2 (Fosl2), potentiates the rate of myocardial accretion from the zebrafish SHF. fosl2 mutants initiate accretion appropriately, but cardiomyocyte production is sluggish, resulting in a ventricular deficit coupled with an accumulation of SHF progenitors. Surprisingly, mutant embryos eventually correct the myocardial deficit by extending the accretion window. Overexpression of Fosl2 also compromises production of SHF-derived ventricular cardiomyocytes, a phenotype that is consistent with precocious depletion of the progenitor pool. Our data implicate Fosl2 in promoting the progenitor to cardiomyocyte transition and uncover the existence of regulatory mechanisms to ensure appropriate SHF-mediated cardiomyocyte contribution irrespective of embryonic stage. PMID:26732840

  9. The AP-1 transcription factor component Fosl2 potentiates the rate of myocardial differentiation from the zebrafish second heart field.

    PubMed

    Jahangiri, Leila; Sharpe, Michka; Novikov, Natasha; González-Rosa, Juan Manuel; Borikova, Asya; Nevis, Kathleen; Paffett-Lugassy, Noelle; Zhao, Long; Adams, Meghan; Guner-Ataman, Burcu; Burns, Caroline E; Burns, C Geoffrey

    2016-01-01

    The vertebrate heart forms through successive phases of cardiomyocyte differentiation. Initially, cardiomyocytes derived from first heart field (FHF) progenitors assemble the linear heart tube. Thereafter, second heart field (SHF) progenitors differentiate into cardiomyocytes that are accreted to the poles of the heart tube over a well-defined developmental window. Although heart tube elongation deficiencies lead to life-threatening congenital heart defects, the variables controlling the initiation, rate and duration of myocardial accretion remain obscure. Here, we demonstrate that the AP-1 transcription factor, Fos-like antigen 2 (Fosl2), potentiates the rate of myocardial accretion from the zebrafish SHF. fosl2 mutants initiate accretion appropriately, but cardiomyocyte production is sluggish, resulting in a ventricular deficit coupled with an accumulation of SHF progenitors. Surprisingly, mutant embryos eventually correct the myocardial deficit by extending the accretion window. Overexpression of Fosl2 also compromises production of SHF-derived ventricular cardiomyocytes, a phenotype that is consistent with precocious depletion of the progenitor pool. Our data implicate Fosl2 in promoting the progenitor to cardiomyocyte transition and uncover the existence of regulatory mechanisms to ensure appropriate SHF-mediated cardiomyocyte contribution irrespective of embryonic stage. © 2016. Published by The Company of Biologists Ltd.

  10. Ror2/Frizzled Complex Mediates Wnt5a-Induced AP-1 Activation by Regulating Dishevelled Polymerization▿ †

    PubMed Central

    Nishita, Michiru; Itsukushima, Sumiyo; Nomachi, Akira; Endo, Mitsuharu; Wang, ZhiChao; Inaba, Daisuke; Qiao, Sen; Takada, Shinji; Kikuchi, Akira; Minami, Yasuhiro

    2010-01-01

    The receptor tyrosine kinase Ror2 acts as a receptor or coreceptor for Wnt5a to mediate Wnt5a-induced activation of the Wnt/JNK pathway and inhibition of the β-catenin-dependent canonical Wnt pathway. However, little is known about how Ror2 cooperates with another receptor component(s) to mediate Wnt5a signaling. We show here that Ror2 regulates Wnt5a-induced polymerization of Dishevelled (Dvl) and that this Ror2-mediated regulation of Dvl is independent of the cytoplasmic region of Ror2. Ror2 can associate with Frizzled7 (Fz7) via its extracellular cysteine-rich domain to form a receptor complex that is required for the regulation of Dvl and activation of the AP-1 promoter after Wnt5a stimulation. Suppressed expression of Fz7 indeed results in the inhibition of Wnt5a-induced polymerization of Dvl and AP-1 activation. Interestingly, both the DIX and the DEP domains of Dvl are indispensable for Dvl polymerization and subsequent AP-1 activation after Wnt5a stimulation. We further show that polymerized Dvl is colocalized with Rac1 and that suppressed expression of Rac1 inhibits Wnt5a-induced AP-1 activation. Collectively, our results indicate that Ror2/Fz receptor complex plays an important role in the Wnt5a/Rac1/AP-1 pathway by regulating the polymerization of Dvl. PMID:20457807

  11. SARM inhibits both TRIF- and MyD88-mediated AP-1 activation.

    PubMed

    Peng, Jun; Yuan, Quan; Lin, Bin; Panneerselvam, Porkodi; Wang, Xiaowei; Luan, Xiao Lei; Lim, Soon Kok; Leung, Bernard P; Ho, Bow; Ding, Jeak Ling

    2010-06-01

    SARM (sterile alpha- and armadillo-motif-containing protein), the fifth identified TIR (Toll-interleukin 1 receptor (IL-1R)) domain-containing adaptors in humans, downregulates NF-kappaB and IRF3 (interferon-regulatory factor 3)-mediated TLR3 and TLR4 signaling. SARM was characterized as a negative regulator of the TRIF (TIR-domain-containing adaptor protein inducing IFN-beta)-dependent pathway via its interaction with TRIF. However, the precise mechanism of action of SARM remains unclear. Here, we demonstrate that SARM inhibits MAPK activation in human embryonic kidney 293 cells, and U937 cells. Both the TRIF- and MyD88-mediated, as well as basal MAPK activity, were repressed, indicating that SARM-mediated inhibition may not be exclusively directed at TRIF or MyD88, but that SARM may also directly inhibit MAPK phosphorylation. The MAPK inhibition effect was verified by RNAi, which increased the basal level of AP-1. Furthermore, LPS challenge upregulated SARM at both the mRNA and protein levels. Finally, we provide evidence to show that truncated SARM changes its subcellular localization, suggesting the importance of the N-terminal and sterile alpha motif domains in the autoregulation of SARM activity.

  12. The FGFR1 inhibitor PD173074 induces mesenchymal–epithelial transition through the transcription factor AP-1

    PubMed Central

    Nguyen, P T; Tsunematsu, T; Yanagisawa, S; Kudo, Y; Miyauchi, M; Kamata, N; Takata, T

    2013-01-01

    Background: Epithelial–mesenchymal transition (EMT) is a crucial process in cancer progression that provides cancer cells with the ability to escape from the primary focus, invade stromal tissues and migrate to distant regions. Cell lines that lack E-cadherin show increased tumorigenesis and metastasis, and the expression levels of E-cadherin and Snail correlate inversely with the prognosis of patients suffering from breast cancer or oral squamous cell carcinoma (OSCC). Moreover, recent studies have shown that most EMT cases are regulated by soluble growth factors or cytokines. Among these factors, fibroblast growth factors (FGFs) execute diverse functions by binding to and activating members of the FGF receptor (FGFR) family, including FGFR1–4. Fibroblast growth factor receptor 1 is an oncoprotein that is involved in tumorigenesis, and PD173074 is known to be a selective inhibitor of FGFR1. However, the roles of FGFR1 and FGFR1 inhibitors have not yet been examined in detail. Methods: Here, we investigated the expression of FGFR1 in head and neck squamous cell carcinoma (HNSCC) and the role of the FGFR1 inhibitor PD173074 in carcinogenesis and the EMT process. Results: Fibroblast growth factor receptor 1 was highly expressed in 54% of HNSCC cases and was significantly correlated with malignant behaviours. Nuclear FGFR1 expression was also observed and correlated well with histological differentiation, the pattern of invasion and abundant nuclear polymorphism. Fibroblast growth factor receptor 1 was also overexpressed in EMT cell lines compared with non-EMT cell lines. Furthermore, treatment of HOC313 cells with PD173074 suppressed cellular proliferation and invasion and reduced ERK1/2 and p38 activation. These cells also demonstrated morphological changes, transforming from spindle- to cobble stone-like in shape. In addition, the expression levels of certain matrix metalloproteinases (MMPs), whose genes contain activator protein-1 (AP-1) promoter sites, as

  13. IL-1β and IL-6 activate inflammatory responses of astrocytes against Naegleria fowleri infection via the modulation of MAPKs and AP-1.

    PubMed

    Kim, J-H; Song, A-R; Sohn, H-J; Lee, J; Yoo, J-K; Kwon, D; Shin, H-J

    2013-01-01

    Naegleria fowleri, a free-living amoeba, has been found in diverse habitats throughout the world. It causes primary amoebic meningoencephalitis in children and young adults. The amoeba attaches to nasal mucosa, migrates along olfactory nerves and enters the brain. Astrocytes are involved in the defence against infection and produce inflammatory responses. In this study, we focus on the mechanism of immune responses in astrocytes. We showed, using RNase protection assay, RT-PCR and ELISA in an in vitro culture system, that N. fowleri lysates induce interleukin-1beta (IL-1β) and IL-6 expression of astrocytes. In addition, cytokine levels of astrocytes gradually decreased due to extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 inhibitors. To determine the transcription factor, we used transcription inhibitor (AP-1 inhibitor), which downregulated IL-1β and IL-6 expression. These results show that AP-1 is related to IL-1β and IL-6 production. N. fowleri-mediated IL-1β and IL-6 expression requires ERK, JNK and p38 mitogen-activated protein kinases (MAPKs) activation in astrocytes. These findings show that N. fowleri-stimulated astrocytes in an in vitro culture system lead to AP-1 activation and the subsequent expressions of IL-1β and IL-6, which are dependent on ERK, JNK and p38 MAPKs activation. These results may imply that proinflammatory cytokines have important roles in inflammatory responses to N. fowleri infection.

  14. C3 toxin activates the stress signaling pathways, JNK and p38, but antagonizes the activation of AP-1 in rat-1 cells.

    PubMed

    Beltman, J; Erickson, J R; Martin, G A; Lyons, J F; Cook, S J

    1999-02-05

    Lysophosphatidic acid (LPA) stimulates the c-Fos serum response element (SRE) by activating two distinct signal pathways regulated by the small GTPases, Ras and RhoA. Ras activates the ERK cascade leading to phosphorylation of the transcription factors Elk-1 and Sap1a at the Ets/TCF site. RhoA regulates an undefined pathway required for the activation of the SRF/CArG site. Here we have examined the role of the Ras and RhoA pathways in activation of the SRE and c-Fos expression in Rat-1 cells. Pertussis toxin and PD98059 strongly inhibited LPA-stimulated c-Fos expression and activation of a SRE:Luc reporter. C3 toxin completely inhibited RhoA function, partially inhibited SRE:Luc activity, but had no effect on LPA-stimulated c-Fos expression. Thus, in a physiological context the Ras-Raf-MEK-ERK pathway, but not RhoA, is required for LPA-stimulated c-Fos expression in Rat-1 cells. C3 toxin stimulated the stress-activated protein kinases JNK and p38 and potentiated c-Jun expression and phosphorylation; these properties were shared by another cellular stress agonist the protein kinase C inhibitor Ro-31-8220. However, C3 toxin alone or in combination with growth factors did not stimulate AP-1:Luc activity and actually antagonized the synergistic activation of AP-1:Luc observed in response to co-stimulation with growth factors and Ro-31-8220. These data indicate that C3 toxin is a cellular stress which antagonizes activation of AP-1 at a point downstream of stress-activated kinase activation or immediate-early gene induction.

  15. Extracellular Signal-Regulated Protein Kinase, c-Jun N-terminal Protein Kinase, and Calcineurin Regulate Transient Receptor Potential M3 (TRPM3) Induced Activation of AP-1.

    PubMed

    Lesch, Andrea; Rössler, Oliver G; Thiel, Gerald

    2017-01-23

    Stimulation of transient receptor potential M3 (TRPM3) cation channels with pregnenolone sulfate induces an influx of Ca(2+) ions into the cells and a rise in the intracellular Ca(2+) concentration, leading to the activation of the activator protein-1 (AP-1) transcription factor. Here, we show that expression of a constitutively active mutant of the Ca(2+) /calmodulin-dependent protein phosphatase calcineurin attenuated pregnenolone sulfate-induced AP-1 activation in TRPM3-expressing cells. Likewise, expression of the regulatory B subunit of calcineurin reduced AP-1 activity in the cells following stimulation of TRPM3 channels. MAP kinase phosphatase-1 has been shown to attenuate TRPM3-mediated AP-1 activation. Here, we show that pregnenolone sulfate-induced stimulation of TRPM3 triggers the phosphorylation and activation of the MAP kinase extracellular signal-regulated protein kinase (ERK1/2). Pharmacological and genetic experiments revealed that stimulation of ERK1/2 is essential for the activation of AP-1 in cells expressing stimulated TRPM3 channels. ERK1/2 is required for the activation of the transcription factor c-Jun, a key component of the AP-1 transcription factor, and regulates c-Fos promoter activity. In addition, we identified c-Jun N-terminal protein kinase (JNK1/2) as a second signal transducer of activated TRPM3 channels. Together, the data show that calcineurin and the protein kinases ERK1/2 and JNK1/2 are important regulators within the signaling cascade connecting TRPM3 channel stimulation with increased AP-1-regulated transcription. This article is protected by copyright. All rights reserved.

  16. Sargahydroquinoic acid inhibits TNFα-induced AP-1 and NF-κB signaling in HaCaT cells through PPARα activation

    SciTech Connect

    Jeon, Youngsic; Jung, Yujung; Kim, Min Cheol; Kwon, Hak Cheol; Kang, Ki Sung; Kim, Yong Kee; Kim, Su-Nam

    2014-08-08

    Highlights: • SHQA increases PPARα/γ transactivation and inhibits MMP-2/-9 expression. • SHQA inhibits TNFα-induced AP-1 and MAPK signaling. • SHQA inhibits TNFα-induced p65 translocation and IκBα phosphorylation. • SHQA inhibits TNFα-induced AP-1 and NF-κB signaling via PPARα. - Abstract: Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily of ligand-activated transcription factors and expressed in various cell types in the skin, including keratinocytes, fibroblasts and infiltrating immune cells. Thus, their ligands are targets for the treatment of various skin disorders, such as photo-aging and chronological aging of skin. Intensive studies have revealed that PPARα/γ functions in photo-aging and age-related inflammation by regulating matrix metalloproteinases (MMPs) via activator protein-1 (AP-1) and nuclear factor kappa B (NF-κB). However, the detailed mechanism of PPARα/γ’s role in skin aging has not yet been elucidated. In this study, we confirmed that sargahydroquinoic acid (SHQA) as a PPARα/γ ligand significantly decreased Tumor Necrosis Factor-alpha (TNFα)-induced MMP-2/-9 expression by downregulating TNFα-induced transcription factors, subsequently reducing IκBα degradation and blocking NF-κB p65 nuclear translocation in HaCaT human epidermal keratinocyte cells. Treatment of cells with SHQA and GW6471 (PPARα antagonist) not bisphenol A diglycidyl ether (PPARγ antagonists), reversed the effect on TNFα-induced inflammatory signaling pathway activation. Taken together, our data suggest that SHQA inhibit TNFα-induced MMP-2/-9 expression and age-related inflammation by suppressing AP-1 and NF-κB pathway via PPARα.

  17. TLR7 and CD40 cooperate in IL-6 production via enhanced JNK and AP-1 activation.

    PubMed

    Vanden Bush, Tony J; Bishop, Gail A

    2008-02-01

    During vaccination or infection, adaptive and innate immune receptors of B cells are engaged by microbial antigens/ligands. A better understanding of how innate and adaptive signaling pathways interact could enlighten B lymphocyte biology as well as aid immunotherapy strategies and vaccine design. To address this goal, we examined the effects of TLR stimulation on BCR and CD40-induced B cell activation. Synergistic production of IL-6 was observed in both human and mouse primary B cells stimulated through B cell antigen receptors, CD40 and TLR7, and these two receptors also cooperated independently of BCR signals. The enhanced IL-6 production was dependent upon the activity of c-Jun kinase (JNK) and cFos. Dual stimulation through CD40 and TLR7 markedly enhanced JNK activity. The increased level of active JNK in dual-stimulated cells was accompanied by an increase in the level of active AP-1 monomers cJun and cFos. The stimulation of B cells through both CD40 and TLR7 therefore enhanced the production of cytokines through increased JNK signaling and AP-1 activity. In addition, the dual stimulation increased cFos/AP-1 species in stimulated cells, effectively expanding the repertoire of AP-1 dimers as compared to singly stimulated B cells.

  18. Differential expression of AP-1 transcription factor genes c-fos and c-jun in the helminth parasites Taenia crassiceps and Taenia solium.

    PubMed

    Morales-Montor, J; Escobedo, G; Rodriguez-Dorantes, M; Téllez-Ascencio, N; Cerbón, M A; Larralde, C

    2004-08-01

    Homologues of c-fos and c-jun from total DNA of Taenia crassiceps and Taenia solium were cloned and sequenced. The amino acid alignment analysis revealed that c-fos DNAs from T. crassiceps and T. solium were highly homologous (96%), and both have high homology compared to several mammalian c-fos proteins (93% to mouse, 96% to rat and 86% to human). The c-jun protein alignment showed higher homology (T. crassiceps and T. solium have 98%), when compared with mouse, rat and human, being 92%, 98% and 93% respectively. RT-PCR amplification of the parasite's total RNA, showed that T. crassiceps expressed both AP-1 complex genes, while T. solium only expressed c-fos. Southern blot hybridization analysis confirmed the true origin of each amplified gene. AP-1 transcription gene expression is regulated by oestradiol in the same fashion as their mammalian counterparts only in T. crassiceps. To study if AP-1 genes are involved in a physiological function of the cyst, reproduction was studied in vitro. Oestradiol treatment stimulated reproduction in T. crassiceps but not in T. solium cysticerci. This is the first report of the detection and functionality of AP-1 transcription factor genes in any species of helminth parasite.

  19. Molecular targets of the antiinflammatory Harpagophytum procumbens (devil's claw): inhibition of TNFα and COX-2 gene expression by preventing activation of AP-1.

    PubMed

    Fiebich, Bernd L; Muñoz, Eduardo; Rose, Thorsten; Weiss, Gabriele; McGregor, Gerard P

    2012-06-01

    Harpagophytum procumbens (Hp) is often used in the supportive treatment of inflammatory and degenerative diseases of the skeletal system. Although the clinical efficacy in osteoarthritis has been demonstrated in clinical trials, the molecular target(s) of Hp are unclear. This study quantified the effects of the ethanol Hp extract (60% v/v ethanol, sole active ingredient of Pascoe®-Agil), on the expression and release of the major pro-inflammatory mediators in LPS-stimulated human monocytes and the intracellular signalling pathways involved in inflammation. The Hp extract dose-dependently inhibited the release of TNFα as well as that of interleukin (IL)-6, IL-1β and prostaglandin E₂ (PGE₂). The Hp prevented TNFα and IL-6 mRNA expression in human monocytes and cyclooxygenase-2 (COX-2) in RAW 264.7 cells. Furthermore, the Hp extract inhibited LPS-stimulated AP-1-mediated gene transcription activity and binding to the AP-1 response elements. The extract had no effect on the LPS-induced binding of nuclear factor-κB in RAW 264.7 cells, on LPS-induced degradation of IκBα or on LPS-induced activation of mitogen-activated protein kinases (MAPK), p38MAPK and JNK in human monocytes. The data indicate that a standardized ethanol Hp extract inhibits induction of pro-inflammatory gene expression, possibly by blocking the AP-1 pathway. This is novel evidence of a possible mechanism of action of this antiinflammatory drug.

  20. Extracellular histones induce tissue factor expression in vascular endothelial cells via TLR and activation of NF-κB and AP-1.

    PubMed

    Yang, Xinyu; Li, Lin; Liu, Jin; Lv, Ben; Chen, Fangping

    2016-01-01

    Extracellular histones have been recognized recently as proinflammatory mediators; they are released from dying cells in response to inflammatory challenge, contributing to endothelial cell dysfunction, thrombin formation, organ failure, and death during sepsis. Clinical studies suggest that the plasma concentration of the histone-DNA complex is correlated with the severity of DIC and is a poor independent prognostic marker in sepsis. In addition, platelet activation stimulates thrombus formation. Whether histones contribute to procoagulant activity in other ways remains elusive. In this study, we confirmed that histones induce tissue factor (TF) expression in a concentration- and time-dependent manner in vascular endothelial cells (ECs) and macrophages. However, histones did not affect TF pathway inhibitor expression. Moreover, blocking the cell surface receptors TLR4 and TLR2 with specific neutralizing antibodies significantly reduced histone-induced TF expression. Furthermore, histones enhanced the nuclear translocation of NF-κB (c-Rel/p65) and AP-1 expression in a time-dependent manner in ECs. Mutating NF-κB and AP-1 significantly reduced histone-induced TF expression. Altogether, our experiments suggest that histone induces TF expression in ECs via cell surface receptors TLR4 and TLR2, simultaneously depending on the activation of the transcription factors NF-κB and AP-1.

  1. Signaling through P2X7 receptor in human T cells involves p56lck, MAP kinases, and transcription factors AP-1 and NF-kappa B.

    PubMed

    Budagian, Vadim; Bulanova, Elena; Brovko, Luba; Orinska, Zane; Fayad, Raja; Paus, Ralf; Bulfone-Paus, Silvia

    2003-01-17

    ATP-gated ion channel P2X receptors are expressed on the surface of most immune cells and can trigger multiple cellular responses, such as membrane permeabilization, cytokine production, and cell proliferation or apoptosis. Despite broad distribution and pleiotropic activities, signaling pathways downstream of these ionotropic receptors are still poorly understood. Here, we describe intracellular signaling events in Jurkat cells treated with millimolar concentrations of extracellular ATP. Within minutes, ATP treatment resulted in the phosphorylation and activation of p56(lck) kinase, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase but not p38 kinase. These effects were wholly dependent upon the presence of extracellular Ca(2+) ions in the culture medium. Nevertheless, calmodulin antagonist calmidazolium and CaM kinase inhibitor KN-93 both had no effect on the activation of p56(lck) and ERK, whereas a pretreatment of Jurkat cells with MAP kinase kinase inhibitor P098059 was able to abrogate phosphorylation of ERK. Further, expression of c-Jun and c-Fos proteins and activator protein (AP-1) DNA binding activity were enhanced in a time-dependent manner. In contrast, DNA binding activity of NF-kappa B was reduced. ATP failed to stimulate the phosphorylation of ERK and c-Jun N-terminal kinase and activation of AP-1 in the p56(lck)-deficient isogenic T cell line JCaM1, suggesting a critical role for p56(lck) kinase in downstream signaling. Regarding the biological significance of the ATP-induced signaling events we show that although extracellular ATP was able to stimulate proliferation of both Jurkat and JCaM1 cells, an increase in interleukin-2 transcription was observed only in Jurkat cells. The nucleotide selectivity and pharmacological profile data supported the evidence that the ATP-induced effects in Jurkat cells were mediated through the P2X7 receptor. Taken together, these results demonstrate the ability of extracellular ATP to activate

  2. Delta FosB and AP-1-mediated transcription modulate cannabinoid CB₁ receptor signaling and desensitization in striatal and limbic brain regions.

    PubMed

    Lazenka, Matthew F; David, Bethany G; Lichtman, Aron H; Nestler, Eric J; Selley, Dana E; Sim-Selley, Laura J

    2014-10-01

    Repeated Δ(9)-tetrahydrocannabinol (THC) administration produces cannabinoid type 1 receptor (CB₁R) desensitization and downregulation, as well as tolerance to its in vivo pharmacological effects. However, the magnitude of CB₁R desensitization varies by brain region, with CB₁Rs in the striatum and its output nuclei undergoing less desensitization than other regions. A growing body of data indicates that regional differences in CB₁R desensitization are produced, in part, by THC-mediated induction of the stable transcription factor, ΔFosB, and subsequent regulation of CB₁Rs. The purpose of the present study was to determine whether THC-mediated induction of ΔFosB in the striatum inhibits CB₁R desensitization in the striatum and output nuclei. This hypothesis was tested using bitransgenic mice with inducible expression of ΔFosB or ΔcJun, a dominant negative inhibitor of AP-1-mediated transcription, in specific forebrain regions. Mice were treated repeatedly with escalating doses of THC or vehicle for 6.5 days, and CB₁R-mediated G-protein activation was assessed using CP55,940-stimulated [(35)S]GTPγS autoradiography. Overexpression of ΔFosB in striatal dopamine type 1 receptor-containing (D1R) medium spiny neurons (MSNs) attenuated CB₁R desensitization in the substantia nigra, ventral tegmental area (VTA) and amygdala. Expression of ΔcJun in striatal D1R- and dopamine type 2 receptor (D2R)-containing MSNs enhanced CB₁R desensitization in the caudate-putamen and attenuated desensitization in the hippocampus and VTA. THC-mediated in vivo pharmacological effects were then assessed in ΔcJun-expressing mice. Tolerance to THC-mediated hypomotility was enhanced in ΔcJun-expressing mice. These data reveal that ΔFosB and possibly other AP-1 binding proteins regulate CB₁R signaling and adaptation in the striatum and limbic system. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Nobiletin and tangeretin ameliorate scratching behavior in mice by inhibiting the action of histamine and the activation of NF-κB, AP-1 and p38.

    PubMed

    Jang, Se-Eun; Ryu, Kwon-Ryeol; Park, Sung-Hwan; Chung, Suna; Teruya, Yuto; Han, Myung Joo; Woo, Je-Tae; Kim, Dong-Hyun

    2013-11-01

    Nobiletin and tangeretin are polymethoxy flavonoids that are abundantly present in the pericarp of Citrus unshiu (family Rutaceae) and the fruit of Citrus depressa (family Rutaceae). They exhibit various biological activities, including anti-inflammatory and anti-asthmatic effects. To evaluate the anti-allergic effects of nobiletin and tangeretin, we measured their inhibitory effects in histamine- or compound 48/80-induced scratching behavioral mice. Nobiletin and tangeretin potently inhibited scratching behavior, as well as histamine-induced vascular permeability. Furthermore, they inhibited the expression of the allergic cytokines, IL-4 and TNF-α as well as the activation of their transcription factors NF-κB, AP-1 and p38 in histamine-stimulated skin tissues. They also inhibited the expression of IL-4 and TNF-α and the activation of NF-κB and c-jun in PMA-stimulated RBL-2H3 cells. Furthermore, nobiletin and tangeretin inhibited protein kinase C (PKC) activity and the IgE-induced degranulation of RBL-2H3 cells. These agents showed potent anti-histamine effect through the Magnus test when guinea pig ileum was used. Based on these results, nobiletin and tangeretin may ameliorate scratching behavioral reactions by inhibiting the action of histamine as well as the activation of the transcription factors NF-κB and AP-1 via PKC.

  4. A wogonin-rich-fraction of Scutellaria baicalensis root extract exerts chondroprotective effects by suppressing IL-1β-induced activation of AP-1 in human OA chondrocytes

    PubMed Central

    Khan, Nazir M.; Haseeb, Abdul; Ansari, Mohammad Y.; Haqqi, Tariq M.

    2017-01-01

    Osteoarthritis (OA) is a common joint disorder with varying degrees of inflammation and sustained oxidative stress. The root extract of Scutellaria baicalensis (SBE) has been used for the treatment of inflammatory and other diseases. Here, we performed activity-guided HPLC-fractionation of SBE, identified the active ingredient(s) and investigated its chondroprotective potential. We found that the Wogonin containing fraction-4 (F4) was the most potent fraction based on its ability to inhibit ROS production and the suppression of catabolic markers including IL-6, COX-2, iNOS, MMP-3, MMP-9, MMP-13 and ADAMTS-4 in IL-1β-treated OA chondrocytes. OA chondrocytes treated with F4 in the presence of IL-1β showed significantly enhanced expression of anabolic genes ACAN and COL2A1. In an in vitro model of cartilage degradation treatment with F4 inhibited s-GAG release from IL-1β-treated human cartilage explants. The inhibitory effect of F4 was not mediated through the inhibition of MAPKs and NF-κB activation but was mediated through the suppression of c-Fos/AP-1 activity at transcriptional and post transcriptional levels in OA chondrocytes. Purified Wogonin mimicked the effects of F4 in IL-1β-stimulated OA chondrocytes. Our data demonstrates that a Wogonin-rich fraction of SBE exert chondroprotective effects through the suppression of c-Fos/AP-1 expression and activity in OA chondrocytes under pathological conditions. PMID:28256567

  5. Human cytomegalovirus contains a tegument protein that enhances transcription from promoters with upstream ATF and AP-1 cis-acting elements.

    PubMed Central

    Liu, B; Stinski, M F

    1992-01-01

    The tegument proteins of human cytomegalovirus are introduced into cells as components of infectious virus. The tegument proteins may affect viral and cellular transcription prior to the synthesis of the immediate-early viral regulatory proteins. The phosphorylated tegument protein of 71 kDa (pp71) is reported to be encoded by the UL82 gene. The UL82 gene products transactivated promoters containing upstream ATF or AP-1 binding sites. In contrast, the phosphorylated tegument protein of 65 kDa (pp65), encoded by the UL83 gene, had no detectable effect on these promoters. Enhancement by UL82 of downstream transcription was directly proportional to the number of upstream ATF sites. Response to UL82 transactivation was abolished by mutation of the ATF site. Mutation in the carboxy-terminal region of UL82 also eliminated transactivation. Even though the major immediate-early promoter of human cytomegalovirus is a strong enhancer-containing promoter, UL82 further enhanced its transcription as much as 20-fold. The mechanism of UL82 enhancement of transcription from viral or cellular promoters is not known, but the enhancement may be mediated by triggering one of the protein kinase signaling pathways, increasing the affinity of ATF or AP-1 for the target sequence, or stabilizing the complex between the eucaryotic transcription factor and the target sequence. Images PMID:1318413

  6. Potent Anti-Inflammatory Activity of Ursolic Acid, a Triterpenoid Antioxidant, Is Mediated through Suppression of NF-κB, AP-1 and NF-AT

    PubMed Central

    Checker, Rahul; Sandur, Santosh K.; Sharma, Deepak; Patwardhan, Raghavendra S.; Jayakumar, S.; Kohli, Vineet; Sethi, Gautam; Aggarwal, Bharat B.; Sainis, Krishna B.

    2012-01-01

    Background Ursolic acid (UA), a pentacyclic triterpenoid carboxylic acid, is the major component of many plants including apples, basil, cranberries, peppermint, rosemary, oregano and prunes and has been reported to possess antioxidant and anti-tumor properties. These properties of UA have been attributed to its ability to suppress NF-κB (nuclear factor kappa B) activation. Since NF-κB, in co-ordination with NF-AT (nuclear factor of activated T cells) and AP-1(activator protein-1), is known to regulate inflammatory genes, we hypothesized that UA might exhibit potent anti-inflammatory effects. Methodology/Principal Findings The anti-inflammatory effects of UA were assessed in activated T cells, B cells and macrophages. Effects of UA on ERK, JNK, NF-κB, AP-1 and NF-AT were studied to elucidate its mechanism of action. In vivo efficacy of UA was studied using mouse model of graft-versus-host disease. UA inhibited activation, proliferation and cytokine secretion in T cells, B cells and macrophages. UA inhibited mitogen-induced up-regulation of activation markers and co-stimulatory molecules in T and B cells. It inhibited mitogen-induced phosphorylation of ERK and JNK and suppressed the activation of immunoregulatory transcription factors NF-κB, NF-AT and AP-1 in lymphocytes. Treatment of cells with UA prior to allogenic transplantation significantly delayed induction of acute graft-versus-host disease in mice and also significantly reduced the serum levels of pro-inflammatory cytokines IL-6 and IFN-γ. UA treatment inhibited T cell activation even when added post-mitogenic stimulation demonstrating its therapeutic utility as an anti-inflammatory agent. Conclusions/Significance The present study describes the detailed mechanism of anti-inflammatory activity of UA. Further, UA may find application in the treatment of inflammatory disorders. PMID:22363615

  7. Immunohistochemical analysis of the expression of cellular transcription NFκB (p65), AP-1 (c-Fos and c-Jun), and JAK/STAT in leprosy.

    PubMed

    Silva, Luciana Mota; Hirai, Kelly Emi; de Sousa, Jorge Rodrigues; de Souza, Juarez; Fuzii, Hellen Thais; Dias, Leonidas Braga; Carneiro, Francisca Regina Oliveira; de Souza Aarão, Tinara Leila; Quaresma, Juarez Antonio Simões

    2015-05-01

    Leprosy is a disease whose clinical spectrum depends on the cytokine patterns produced during the early stages of the immune response. The main objective of this study was to describe the activation pattern of cellular transcription factors and to correlate these factors with the clinical forms of leprosy. Skin samples were obtained from 16 patients with the tuberculoid (TT) form and 14 with the lepromatous (LL) form. The histologic sections were immunostained with anti-c-Fos and anti-c-Jun monoclonal antibodies for investigation of AP-1, anti-NFκB p65 for the study of NFκB, and anti-JAK2, STAT1, STAT3, and STAT4 for investigation of the JAK/STAT pathway. Cells expressing STAT1 were more frequent in the TT form than in LL lesions (P = .0096), in agreement with the protective immunity provided by IFN-γ. STAT4 was also more highly expressed in the TT form than in the LL form (P = .0098). This transcription factor is essential for the development of a Th1 response because it is associated with interleukin-12. NFκB (p65) and STAT4 expression in the TT form showed a strong and significant correlation (r = 0.7556 and P = .0007). A moderate and significant correlation was observed between JAK2 and STAT4 in the TT form (r = 0.6637 and P = .0051), with these factors responding to interleukin-12 in Th1 profiles. The results suggest that STAT1, JAK2, and NFκB, together with STAT4, contribute to the development of cell-mediated immunity, which is able to contain the proliferation of Mycobacterium leprae.

  8. Activation of Nrf2 Reduces UVA-Mediated MMP-1 Upregulation via MAPK/AP-1 Signaling Cascades: The Photoprotective Effects of Sulforaphane and Hispidulin

    PubMed Central

    Chaiprasongsuk, Anyamanee; Lohakul, Jinaphat; Soontrapa, Kitipong; Sampattavanich, Somponnat; Akarasereenont, Pravit

    2017-01-01

    UVA irradiation plays a role in premature aging of the skin through triggering oxidative stress-associated stimulation of matrix metalloproteinase-1 (MMP-1) responsible for collagen degradation, a hallmark of photoaged skin. Compounds that can activate nuclear factor E2-related factor 2 (Nrf2), a transcription factor regulating antioxidant gene expression, should therefore serve as effective antiphotoaging agents. We investigated whether genetic silencing of Nrf2 could relieve UVA-mediated MMP-1 upregulation via activation of mitogen-activated protein kinase (MAPK)/activator protein 1 (AP-1) signaling using human keratinocyte cell line (HaCaT). Antiphotoaging effects of hispidulin (HPD) and sulforaphane (SFN) were assessed on their abilities to activate Nrf2 in controlling MMP-1 and collagen expressions in association with phosphorylation of MAPKs (extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38), c-Jun, and c-Fos, using the skin of BALB/c mice subjected to repetitive UVA irradiation. Our findings suggested that depletion of Nrf2 promoted both mRNA expression and activity of MMP-1 in the UVA-irradiated HaCaT cells. Treatment of Nrf2 knocked-down HaCaT cells with MAPK inhibitors significantly suppressed UVA-induced MMP-1 and AP-1 activities. Moreover, pretreatment of the mouse skin with HPD and SFN, which could activate Nrf2, provided protective effects against UVA-mediated MMP-1 induction and collagen depletion in correlation with the decreased levels of phosphorylated MAPKs, c-Jun, and c-Fos in the mouse skin. In conclusion, Nrf2 could influence UVA-mediated MMP-1 upregulation through the MAPK/AP-1 signaling cascades. HPD and SFN may therefore represent promising antiphotoaging candidates. PMID:28011874

  9. AP-1 blockade in breast cancer cells causes cell cycle arrest by suppressing G1 cyclin expression and reducing cyclin-dependent kinase activity.

    PubMed

    Liu, Yongmin; Lu, Chunhua; Shen, Qiang; Munoz-Medellin, Debbie; Kim, Heetae; Brown, Powel H

    2004-10-28

    The AP-1 transcription factor is a central component of signal transduction pathways in many cells, although the exact role of AP-1 in controlling cell growth and malignant transformation is unknown. We have previously shown that AP-1 complexes are activated by peptide and steroid growth factors in both normal and malignant breast cells, and that blocking AP-1 by overexpressing a dominant-negative form of cJun (cJun-DN, TAM67) inhibits breast cancer cell growth both in vivo and in vitro. We hypothesized that TAM67 inhibits cell growth by altering the expression of cell cycle regulatory proteins, thus causing a cell cycle block. In the present study, we used clones of MCF7 breast cancer cells that express TAM67 under the control of an inducible promoter. First, we determined the effect of AP-1 blockade on cell growth, then we performed 3H-thymidine incorporation and flow cytometry assays to investigate whether TAM67 inhibits the cell cycle. We observed that in the presence of serum TAM67 inhibited cell growth and caused a block in the G1 phase of the cell cycle. Next, we performed Western-blotting and CDK kinase assays to determine the effects of TAM67 on retinoblastoma (Rb) phosphorylation, the expression of cell cycle regulatory proteins, and CDK activity. We discovered that TAM67 inhibited Rb phosphorylation and reduced E2F activity. We also found that TAM67 decreased the expression of D and E cyclins, reduced CDK2 and CDK4 activity, and increased the CDK inhibitor p27. The studies of gene expression at the RNA level showed that TAM67 decreased cyclin Ds mRNA expression. Our study suggests that in the presence of serum, TAM67 inhibits breast cancer growth predominantly by inducing inhibitors of cyclin-dependent kinases (such as p27) and by reducing the expression of the cyclins involved in transitioning from G1 into S phase of the cell cycle. These studies lay the foundation for future attempt to develop new agents for the treatment and prevention of breast

  10. Surgical intervention for symptomatic benign prostatic hyperplasia is correlated with expression of the AP-1 transcription factor network.

    PubMed

    Lin-Tsai, Opal; Clark, Peter E; Miller, Nicole L; Fowke, Jay H; Hameed, Omar; Hayward, Simon W; Strand, Douglas W

    2014-05-01

    Approximately one-third of patients fail medical treatment for benign prostatic hyperplasia and associated lower urinary tract symptoms (BPH/LUTS) requiring surgical intervention. Our purpose was to establish a molecular characterization for patients undergoing surgical intervention for LUTS to address therapeutic deficiencies. Clinical, molecular, and histopathological profiles were analyzed in 26 patients undergoing surgery for severe LUTS. Incidental transitional zone nodules were isolated from 37 patients with mild symptoms undergoing radical prostatectomy. Clinical parameters including age, prostate volume, medication, prostate specific antigen, symptom score, body mass index, and incidence of diabetes were collected. Multivariate logistic regression analysis with adjustments for potential confounding variables was used to examine associations between patient clinical characteristics and molecular targets identified through molecular profiling. Compared to incidental BPH, progressive symptomatic BPH was associated with increased expression of the activating protein-1 transcription factor/chemokine network. As expected, inverse correlations were drawn between androgen receptor levels and age, as well as between 5α-reductase inhibitor (5ARI) treatment and tissue prostate specific antigen levels; however, a novel association was also drawn between 5ARI treatment and increased c-FOS expression. This study provides molecular evidence that a network of pro-inflammatory activating protein-1 transcription factors and associated chemokines are highly enriched in symptomatic prostate disease, a profile that molecularly categorizes with many other chronic autoimmune diseases. Because 5ARI treatment was associated with increased c-FOS expression, future studies should explore whether increased activating protein-1 proteins are causal factors in the development of symptomatic prostate disease, inflammation or resistance to traditional hormonal therapy. © 2014 Wiley

  11. Radical Scavenging Activity-Based and AP-1-Targeted Anti-Inflammatory Effects of Lutein in Macrophage-Like and Skin Keratinocytic Cells

    PubMed Central

    Oh, Jueun; Kim, Ji Hye; Park, Jae Gwang; Yi, Young-Su; Park, Kye Won; Rho, Ho Sik; Lee, Min-Seuk; Yoo, Jae Won; Kang, Seung-Hyun; Hong, Yong Deog; Shin, Song Seok; Cho, Jae Youl

    2013-01-01

    Lutein is a naturally occurring carotenoid with antioxidative, antitumorigenic, antiangiogenic, photoprotective, hepatoprotective, and neuroprotective properties. Although the anti-inflammatory effects of lutein have previously been described, the mechanism of its anti-inflammatory action has not been fully elucidated. Therefore, in the present study, we aimed to investigate the regulatory activity of lutein in the inflammatory responses of skin-derived keratinocytes or macrophages and to elucidate the mechanism of its inhibitory action. Lutein significantly reduced several skin inflammatory responses, including increased expression of interleukin-(IL-) 6 from LPS-treated macrophages, upregulation of cyclooxygenase-(COX-) 2 from interferon-γ/tumor necrosis-factor-(TNF-) α-treated HaCaT cells, and the enhancement of matrix-metallopeptidase-(MMP-) 9 level in UV-irradiated keratinocytes. By evaluating the intracellular signaling pathway and the nuclear transcription factor levels, we determined that lutein inhibited the activation of redox-sensitive AP-1 pathway by suppressing the activation of p38 and c-Jun-N-terminal kinase (JNK). Evaluation of the radical and ROS scavenging activities further revealed that lutein was able to act as a strong anti-oxidant. Taken together, our findings strongly suggest that lutein-mediated AP-1 suppression and anti-inflammatory activity are the result of its strong antioxidative and p38/JNK inhibitory activities. These findings can be applied for the preparation of anti-inflammatory and cosmetic remedies for inflammatory diseases of the skin. PMID:23533312

  12. GDNF-independent ureteric budding: role of PI3K-independent activation of AKT and FOSB/JUN/AP-1 signaling

    PubMed Central

    Tee, James B.; Choi, Yohan; Dnyanmote, Ankur; Decambre, Marvalyn; Ito, Chiharu; Bush, Kevin T.; Nigam, Sanjay K.

    2013-01-01

    Summary A significant fraction of mice deficient in either glial cell-derived neurotrophic factor (GDNF) or its co-receptors (Gfrα1, Ret), undergoes ureteric bud (UB) outgrowth leading to the formation of a rudimentary kidney. Previous studies using the isolated Wolffian duct (WD) culture indicate that activation of fibroblast growth factor (FGF) receptor signaling, together with suppression of BMP/Activin signaling, is critical for GDNF-independent WD budding (Maeshima et al., 2007). By expression analysis of embryonic kidney from Ret(−/−) mice, we found the upregulation of several FGFs, including FGF7. To examine the intracellular pathways, we then analyzed GDNF-dependent and GDNF-independent budding in the isolated WD culture. In both conditions, Akt activation was found to be important; however, whereas this occurred through PI3-kinase in GDNF-dependent budding, in the case of GDNF-independent budding, Akt activation was apparently via a PI3-kinase independent mechanism. Jnk signaling and the AP-1 transcription factor complex were also implicated in GDNF-independent budding. FosB, a binding partner of c-Jun in the formation of AP-1, was the most highly upregulated gene in the ret knockout kidney (in which budding had still occurred), and we found that its siRNA-mediated knockdown in isolated WDs also blocked GDNF-independent budding. Taken together with the finding that inhibition of Jnk signaling does not block Akt activation/phosphorylation in GDNF-independent budding, the data support necessary roles for both FosB/Jun/AP-1 signaling and PI3-kinase-independent activation of Akt in GDNF-independent budding. A model is proposed for signaling events that involve Akt and JNK working to regulate GDNF-independent WD budding. PMID:24143282

  13. GDNF-independent ureteric budding: role of PI3K-independent activation of AKT and FOSB/JUN/AP-1 signaling.

    PubMed

    Tee, James B; Choi, Yohan; Dnyanmote, Ankur; Decambre, Marvalyn; Ito, Chiharu; Bush, Kevin T; Nigam, Sanjay K

    2013-01-01

    A significant fraction of mice deficient in either glial cell-derived neurotrophic factor (GDNF) or its co-receptors (Gfrα1, Ret), undergoes ureteric bud (UB) outgrowth leading to the formation of a rudimentary kidney. Previous studies using the isolated Wolffian duct (WD) culture indicate that activation of fibroblast growth factor (FGF) receptor signaling, together with suppression of BMP/Activin signaling, is critical for GDNF-independent WD budding (Maeshima et al., 2007). By expression analysis of embryonic kidney from Ret((-/-)) mice, we found the upregulation of several FGFs, including FGF7. To examine the intracellular pathways, we then analyzed GDNF-dependent and GDNF-independent budding in the isolated WD culture. In both conditions, Akt activation was found to be important; however, whereas this occurred through PI3-kinase in GDNF-dependent budding, in the case of GDNF-independent budding, Akt activation was apparently via a PI3-kinase independent mechanism. Jnk signaling and the AP-1 transcription factor complex were also implicated in GDNF-independent budding. FosB, a binding partner of c-Jun in the formation of AP-1, was the most highly upregulated gene in the ret knockout kidney (in which budding had still occurred), and we found that its siRNA-mediated knockdown in isolated WDs also blocked GDNF-independent budding. Taken together with the finding that inhibition of Jnk signaling does not block Akt activation/phosphorylation in GDNF-independent budding, the data support necessary roles for both FosB/Jun/AP-1 signaling and PI3-kinase-independent activation of Akt in GDNF-independent budding. A model is proposed for signaling events that involve Akt and JNK working to regulate GDNF-independent WD budding.

  14. A novel intronic cAMP response element modulator (CREM) promoter is regulated by activator protein-1 (AP-1) and accounts for altered activation-induced CREM expression in T cells from patients with systemic lupus erythematosus.

    PubMed

    Rauen, Thomas; Benedyk, Konrad; Juang, Yuang-Taung; Kerkhoff, Claus; Kyttaris, Vasileios C; Roth, Johannes; Tsokos, George C; Tenbrock, Klaus

    2011-09-16

    The transcriptional repressor cAMP response element modulator (CREM) α has important roles in normal T cell physiology and contributes to aberrant T cell function in patients with systemic lupus erythematosus (SLE). Recently, we characterized a specificity protein-1-dependent promoter located upstream of the CREM gene that accounts for increased basal CREM expression in SLE T cells and reflects disease activity. Here, we identify a novel intronic CREM promoter (denoted P2) in front of the second exon of the CREM gene that harbors putative binding sites for TATA-binding proteins and the transcriptional activator AP-1. DNA binding studies, chromatin immunoprecipitation, and reporter assays confirmed the functional relevance of these sites, and T cell activation through CD3/CD28 stimulation or phorbol 12-myristate 13-acetate/ionomycin treatment enhances P2 promoter activity. Although the basal CREM levels are increased in T cells from SLE patients compared with healthy controls, there are remarkable differences in the regulation of CREM expression in response to T cell activation. Whereas T cells from healthy individuals display increased CREM expression after T cell activation, most likely through AP-1-dependent up-regulation of the P2 promoter, SLE T cells fail to further increase their basal CREM levels upon T cell activation due to a decreased content of the AP-1 family member c-Fos. Because CREM trans-represses c-fos transcription in SLE T cells, we propose an autoregulatory feedback mechanism between CREM and AP-1. Our findings extend the understanding of CREM gene regulation in the context of T cell activation and disclose another difference in the transcriptional machinery in SLE T cells.

  15. Low doses of LPS and minimally oxidized LDL cooperatively activate macrophages via NF-kappaB and AP-1: Possible mechanism for acceleration of atherosclerosis by subclinical endotoxemia

    PubMed Central

    Wiesner, Philipp; Choi, Soo-Ho; Almazan, Felicidad; Benner, Christopher; Huang, Wendy; Diehl, Cody J.; Gonen, Ayelet; Butler, Susan; Witztum, Joseph L.; Glass, Christopher K.; Miller, Yury I.

    2010-01-01

    Rationale Oxidized low-density lipoprotein (LDL) is an important determinant of inflammation in atherosclerotic lesions. It has also been documented that certain chronic infectious diseases, such as periodontitis and chlamydial infection, exacerbate clinical manifestations of atherosclerosis. In addition, low-level but persistent metabolic endotoxemia is often found in diabetic and obese subjects and is induced in mice fed a high-fat diet. Objective In this study, we examined cooperative macrophage activation by low levels of bacterial LPS and by minimally oxidized LDL (mmLDL), as a model for subclinical endotoxemia-complicated atherosclerosis. Methods and Results We found that both in vitro and in vivo, mmLDL and LPS (Kdo2-LipidA) cooperatively activated macrophages to express pro-inflammatory cytokines Cxcl2 (MIP-2), Ccl3 (MIP-1alpha), and Ccl4 (MIP-1beta). Importantly, the mmLDL and LPS cooperative effects were evident at a threshold LPS concentration (1 ng/ml) at which LPS alone induced only a limited macrophage response. Analyzing microarray data with a de novo motif discovery algorithm, we found that genes transcribed by promoters containing an AP-1 binding site were significantly upregulated by co-stimulation with mmLDL and LPS. In a nuclear factor-DNA binding assay, the cooperative effect of mmLDL and LPS co-stimulation on c-Jun and c-Fos DNA binding, but not on p65 or p50, was dependent on mmLDL-induced activation of ERK1/2. In addition, mmLDL induced JNK-dependent derepression of AP-1 by removing the corepressor NCoR from the chemokine promoters. Conclusions The cooperative engagement of AP-1 and NF-kappaB by mmLDL and LPS may constitute a mechanism of increased transcription of inflammatory cytokines within atherosclerotic lesions. PMID:20489162

  16. AP-1 transcription factors, mucin-type molecules and MMPs regulate the IL-11 mediated invasiveness of JEG-3 and HTR-8/SVneo trophoblastic cells.

    PubMed

    Suman, Pankaj; Godbole, Geeta; Thakur, Ravi; Morales-Prieto, Diana M; Modi, Deepak N; Markert, Udo R; Gupta, Satish K

    2012-01-01

    This study examines the IL-11 mediated activation of downstream signaling and expression of effector molecules to resolve the controversies associated with the IL-11 mediated regulation of the invasiveness of two commonly used trophoblastic cell models viz. JEG-3 and HTR-8/SVneo cells. It has been reported that IL-11 increases the invasiveness of JEG-3 cells while, reduces the invasiveness of HTR-8/SVneo cells. Invasion assay performed simultaneously for both the cell lines confirmed the above findings. In addition, HTR-8/SVneo cells showed a higher basal invasiveness than JEG-3 cells. Western blot showed the IL-11 mediated activation of STAT3(tyr705) and STAT1(tyr701) in both the cell lines. However, IL-11 activated the ERK1/2 phosphorylation in JEG-3 cells but, inhibited it in HTR-8/SVneo cells. Within 10 min of IL-11 treatment, p-STAT3(tyr705) was localized inside the nucleus of both the cell lines but, there was enhanced co-localization of protein inhibitor of activated STAT1/3 (PIAS1/3) and p-STAT3(tyr705) in HTR-8/SVneo cells and not in JEG-3 cells. This could be reason for the poor responsiveness of STAT3 responsive genes like mucin 1 (MUC1) in HTR-8/SVneo cells and not in JEG-3 cells. Further, microarray analysis of the IL-11 treated cells revealed differential responsiveness of JEG-3 as compared to HTR-8/SVneo cells. Several family of genes like activator protein-1 (AP-1) transcription factors (Jun and Fos), mucin-type molecules, MMP23B etc showed enhanced expression in IL-11 treated JEG-3 cells while, there was no response or decrease in their expression in IL-11 treated HTR-8/SVneo cells. Expression of these molecules was confirmed by quantitative RT-PCR. In addition, HTR-8/SVneo cells also showed a significant decrease in the expression of MMP2, MMP3 and MMP9 upon IL-11 treatment. Hence, IL-11 mediated differential activation of signaling and expression of effector molecules is responsible for the differential invasive response of JEG-3 and HTR-8/SVneo

  17. AP-1 Transcription Factors, Mucin-Type Molecules and MMPs Regulate the IL-11 Mediated Invasiveness of JEG-3 and HTR-8/SVneo Trophoblastic Cells

    PubMed Central

    Suman, Pankaj; Godbole, Geeta; Thakur, Ravi; Morales-Prieto, Diana M.; Modi, Deepak N.; Markert, Udo R.; Gupta, Satish K.

    2012-01-01

    This study examines the IL-11 mediated activation of downstream signaling and expression of effector molecules to resolve the controversies associated with the IL-11 mediated regulation of the invasiveness of two commonly used trophoblastic cell models viz. JEG-3 and HTR-8/SVneo cells. It has been reported that IL-11 increases the invasiveness of JEG-3 cells while, reduces the invasiveness of HTR-8/SVneo cells. Invasion assay performed simultaneously for both the cell lines confirmed the above findings. In addition, HTR-8/SVneo cells showed a higher basal invasiveness than JEG-3 cells. Western blot showed the IL-11 mediated activation of STAT3(tyr705) and STAT1(tyr701) in both the cell lines. However, IL-11 activated the ERK1/2 phosphorylation in JEG-3 cells but, inhibited it in HTR-8/SVneo cells. Within 10 min of IL-11 treatment, p-STAT3(tyr705) was localized inside the nucleus of both the cell lines but, there was enhanced co-localization of protein inhibitor of activated STAT1/3 (PIAS1/3) and p-STAT3(tyr705) in HTR-8/SVneo cells and not in JEG-3 cells. This could be reason for the poor responsiveness of STAT3 responsive genes like mucin 1 (MUC1) in HTR-8/SVneo cells and not in JEG-3 cells. Further, microarray analysis of the IL-11 treated cells revealed differential responsiveness of JEG-3 as compared to HTR-8/SVneo cells. Several family of genes like activator protein-1 (AP-1) transcription factors (Jun and Fos), mucin-type molecules, MMP23B etc showed enhanced expression in IL-11 treated JEG-3 cells while, there was no response or decrease in their expression in IL-11 treated HTR-8/SVneo cells. Expression of these molecules was confirmed by quantitative RT-PCR. In addition, HTR-8/SVneo cells also showed a significant decrease in the expression of MMP2, MMP3 and MMP9 upon IL-11 treatment. Hence, IL-11 mediated differential activation of signaling and expression of effector molecules is responsible for the differential invasive response of JEG-3 and HTR-8/SVneo

  18. Downregulated AP-1 activity is associated with inhibition of Protein-Kinase-C-dependent CD44 and ezrin localisation and upregulation of PKC theta in A431 cells.

    PubMed

    Stapleton, Genevieve; Malliri, Angeliki; Ozanne, Bradford W

    2002-07-01

    Progression to an invasive, metastatic tumour requires the coordinated expression and function of a number of gene products, as well as their regulation in the context of invasion. The transcription factor AP-1 regulates expression of many of those genes necessary for implementation of the invasion programme. Two such gene products, CD44 and ezrin, are both upregulated in fibroblasts transformed by v-fos and are commonly implicated in cell motility and invasion. Here we report that CD44 and ezrin colocalise to membrane ruffles and microvilli of A431 cells after treatment with EGF. However, A431 cells expressing dominant-negative c-Jun (TAM67), and which as a consequence fail to invade in response to EGF, also fail to correctly localise CD44 and ezrin. CD44 and ezrin are both substrates for Protein Kinase C, and we show that their EGF-dependent colocalisation requires Protein Kinase C activity. Associated with TAM67 expression and disrupted CD44 and ezrin colocalisation is the increased expression and activation of the novel PKC theta isoform. Expression of PKC theta in A431 cells results in the inhibition of cell motility and disrupted localisation of CD44 and ezrin. We propose that AP-1 regulates the integrity of Protein Kinase C signalling and identifies PKC theta as a potential suppressor of the invasion programme.

  19. Anti-inflammatory activities of Physalis alkekengi var. franchetii extract through the inhibition of MMP-9 and AP-1 activation.

    PubMed

    Hong, Ju-Mi; Kwon, Ok-Kyoung; Shin, In-Sik; Song, Hyuck-Hwan; Shin, Na-Rae; Jeon, Chan-Mi; Oh, Sei-Ryang; Han, Sang-Bae; Ahn, Kyung-Seop

    2015-01-01

    Physalis alkekengi has been traditionally used for the treatment of coughs, middle ear infections, and sore throats in Korea, Europe, and China. It exhibits a variety of pharmacological activities such as anti-inflammatory, anti-oxidant, and anti-cancer effects. The anti-inflammatory effects of the P. alkekengi methanol extract (PA) and its molecular mechanisms have not yet been fully investigated. In the present study, the chromatogram of PA was established by UPLC analysis. The anti-inflammatory effects of PA were also investigated using murine microphage cell lines, RAW 264.7 cells, and a murine model of OVA induced asthma. In LPS-stimulated RAW264.7 cells, PA reduced the MMP-9 expression with decreases in the production of nitric oxide, inteleukin-6, and tumor necrosis factor-α. Furthermore, PA suppressed the phosphorylation of MAPKs, which resulted in the inhibition of AP-1 activation. These effects of PA were consistent with the results of the in vivo experiment. PA-treated mice significantly inhibited inflammatory cell counts and cytokine production in bronchoalveolar lavage fluids and airway-hyperresponsiveness in OVA-induced asthmatic mice. PA treated mice also showed a marked inhibition of inducible nitric oxide synthase and MMP-9 expression. In conclusion, our results suggest that PA may be a valuable therapeutic material in treating various inflammatory diseases, including allergic asthma.

  20. Cobalt chloride induces PC12 cells apoptosis through reactive oxygen species and accompanied by AP-1 activation.

    PubMed

    Zou, W; Yan, M; Xu, W; Huo, H; Sun, L; Zheng, Z; Liu, X

    2001-06-15

    Reactive oxygen species (ROS) are supposed to play an important role in hypoxia- and ischemia/reperfusion-mediated neuronal injury with the characteristics of apoptosis. There are many reports showing that cobalt chloride (CoCl(2)) could mimic the hypoxic responses in some aspects including production of ROS in cultured cells. The cytotoxicity of CoCl(2) and its molecular mechanisms have yet to be elucidated. We report that CoCl(2) triggered neuronal PC12 cells apoptosis in a dose- and time-dependent manner. Apoptosis was demonstrated by morphological changes and DNA fragmentation, and was dependent on macromolecular synthesis. Apoptosis was also confirmed by the decrease of the expression of Bcl-X(L). To our knowledge, this is the first documentation of the apoptotic induction of CoCl(2) on PC12 cells. Furthermore, ROS production in PC12 cells was increased during CoCl(2) treatment. Antioxidants, which could inhibit ROS production, significantly blocked CoCl(2)-induced apoptosis, suggesting that apoptosis is mediated by ROS production. We also observed a significant increase of the DNA-binding activity of AP-1 in response to CoCl(2) and this increase was blocked by antioxidants, showing that CoCl(2)-induced apoptosis is accompanied by ROS-activated AP-1. CoCl(2)-treated PC12 cells may serve as an in vitro model for studies of molecular mechanisms in ROS-linked neuronal disorders.

  1. Nitrogen mustard exposure of murine skin induces DNA damage, oxidative stress and activation of MAPK/Akt-AP1 pathway leading to induction of inflammatory and proteolytic mediators.

    PubMed

    Kumar, Dileep; Tewari-Singh, Neera; Agarwal, Chapla; Jain, Anil K; Inturi, Swetha; Kant, Rama; White, Carl W; Agarwal, Rajesh

    2015-06-15

    Our recent studies in SKH-1 hairless mice have demonstrated that topical exposure to nitrogen mustard (NM), an analog of sulfur mustard (SM), triggers the inflammatory response, microvesication and apoptotic cell death. Here, we sought to identify the mechanism/s involved in these NM-induced injury responses. Results obtained show that NM exposure of SKH-1 hairless mouse skin caused H2A.X and p53 phosphorylation and increased p53 accumulation, indicating DNA damage. In addition, NM also induced the activation of MAPKs/ERK1/2, JNK1/2 and p38 as well as that of Akt together with the activation of transcription factor AP1. Also, NM exposure induced robust expression of pro-inflammatory mediators namely cyclooxygenase 2 and inducible nitric oxide synthase and cytokine tumor necrosis factor alpha, and increased the levels of proteolytic mediator matrix metalloproteinase 9. NM exposure of skin also increased lipid peroxidation, 5,5-dimethyl-2-(8-octanoic acid)-1-pyrroline N-oxide protein adduct formation, protein and DNA oxidation indicating an elevated oxidative stress. We also found NM-induced increase in the homologous recombinant repair pathway, suggesting its involvement in the repair of NM-induced DNA damage. Collectively, these results indicate that NM induces oxidative stress, mainly a bi-phasic response in DNA damage and activation of MAPK and Akt pathways, which activate transcription factor AP1 and induce the expression of inflammatory and proteolytic mediators, contributing to the skin injury response by NM. In conclusion, this study for the first time links NM-induced mechanistic changes with our earlier reported murine skin injury lesions with NM, which could be valuable to identify potential therapeutic targets and rescue agents. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Nf-kappab and AP-1 activation is associated with late lumen loss after porcine coronary angioplasty and antiproliferative beta-irradiation.

    PubMed

    Deiner, Carolin; Shagdarsuren, Erdenechimeg; Schwimmbeck, Peter L; Rosenthal, Peter; Loddenkemper, Christoph; Rauch, Ursula; Pauschinger, Matthias; Dietz, Rainer; Schultheiss, Heinz-Peter; Dechend, Ralf; Pels, Klaus

    2007-07-01

    Despite the success of antiproliferative therapies, restenosis remains a common problem after percutaneous transluminal coronary angioplasty (PTCA). Longer-term clinical results of brachytherapy (intracoronary radiation), the lack of long-term clinical results after implantation of drug eluting stents, and the occurrence of late thrombosis after both procedures leave room for skepticism. Neointimal proliferation is not substantially inhibited at late time points after brachytherapy, and late lumen loss with a "catch-up" proliferation can occur. We hypothesized that the transcription factors nuclear factor-{kappa}B (NF-kappaB) and activator protein-1 (AP-1) are involved in these processes. We addressed the role of these mediators in a porcine model of coronary restenosis. Thirty-nine pigs underwent PTCA in two major coronary arteries. One of the two balloon-injured arteries was randomly assigned to receive immediate 20 Gy beta-irradiation (Brachy group) using a noncentered source train ((90)Sr/Y Beta-Cath, Novoste). Animals were sacrificed after 1 day, 14 days, or 28 days. Proliferating cells were labeled prior to euthanasia. At late time points, lumen area was significantly smaller and the inflammatory response was more pronounced in the Brachy group than in the PTCA group. These findings coincided with sustained activation of MMP-9 and transcription factors like NF-kappaB and AP-1. Initially, cell proliferation was reduced in the Brachy group; however, at late time points, differences between the two treatment groups were no longer significant. Brachytherapy initially inhibits cell proliferation; however, cellular and molecular inflammatory processes (e.g. activation of NF-kappaB) are enhanced within the arterial wall. This proinflammatory side effect may be responsible for the observed delayed proliferation and the resulting lumen loss.

  3. Establishment and characterization of cetuximab resistant head and neck squamous cell carcinoma cell lines: focus on the contribution of the AP-1 transcription factor

    PubMed Central

    Boeckx, Carolien; Blockx, Lina; de Beeck, Ken Op; Limame, Ridha; Camp, Guy Van; Peeters, Marc; Vermorken, Jan B; Specenier, Pol; Wouters, An; Baay, Marc; Lardon, Filip

    2015-01-01

    Background: After an initial response to EGFR targeted therapy, secondary resistance almost invariably ensues, thereby limiting the clinical benefit of the drug. Hence, it has been recognized that the successful implementation of targeted therapy in the treatment of HNSCC cancer is very much dependent on predictive biomarkers for patient selection. Methods: We generated an in vitro model of acquired cetuximab resistance by chronically exposing three HNSCC cell lines to increasing cetuximab doses. Gene expression profiles of sensitive parental cells and resistant daughter cells were compared using microarray analysis. Growth inhibitory experiments were performed with an HB-EGF antibody and the MMP inhibitor, both in combination with cetuximab. Characteristics of EMT were analyzed using migration and invasion assays, immunofluorescent vimentin staining and qRT-PCR for several genes involved in this process. The function of the transcription factor AP-1 was investigated using qRT-PCR for several genes upregulated or downregulated in cetuximab resistant cells. Furthermore, anchorage-independent growth was investigated using the soft agar assay. Results: Gene expression profiling shows that cetuximab resistant cells upregulate several genes, including interleukin 8, the EGFR ligand HB-EGF and the metalloproteinase ADAM19. Cytotoxicity experiments with neutralizing HB-EGF antibody could not induce any growth inhibition, whereas an MMP inhibitor inhibited cell growth in cetuximab resistant cells. However, no synergetic effects combined with cetuximab could be observed. Cetuximab resistant cells showed traits of EMT, as witnessed by increased migratory potential, increased invasive potential, increased vimentine expression and increased expression of several genes involved in EMT. Furthermore, expression of upregulated genes could be repressed by the treatment with apigenin. The cetuximab resistant LICR-HN2 R10.3 cells tend to behave differently in cell culture, forming

  4. A conserved lysine in the estrogen receptor DNA binding domain regulates ligand activation profiles at AP-1 sites, possibly by controlling interactions with a modulating repressor

    PubMed Central

    Uht, Rosalie M; Webb, Paul; Nguyen, Phuong; Price Jr, Richard H; Valentine, Cathleen; Favre, Helene; Kushner, Peter J

    2004-01-01

    Background Estrogen receptors alpha and beta (ERα and ERβ) differentially activate genes with AP-1 elements. ERα activates AP-1 targets via activation functions with estrogens (the AF-dependent pathway), whereas ERβ, and a short version of ERα (ERα DBD-LBD) activate only with anti-estrogens (AF-independent pathway). The DNA binding domain (DBD) plays an important role in both pathways, even though neither pathway requires ERE recognition. Results Mutations of a highly conserved DBD lysine (ERα.K206A/G), lead to super-activation of AP-1 through activation function dependent pathways, up to 200 fold. This super-activity can be elicited either through ER AFs 1 or 2, or that of a heterologous activation function (VP16). The homologous substitution in ERβ, K170A, or in ERα DBD-LBD leads to estrogen-dependent AP-1 activation and loss of the usually potent anti-estrogen effects. Each of numerous K206 substitutions in ERα, except K206R, eliminates anti-estrogen activation and this loss correlates perfectly with a loss of ability to titrate a repressive function from the RU486 bound progesterone receptor. Conclusion We conclude that ER DBDs contain a complex regulatory function that influences ligand activation profiles at AP-1. This function, which requires the integrity of the conserved lysine, both allows for activation at AP-1 with anti-estrogens (with ERβ and ERα DBD-LBD), and prevents ERα from becoming superactive at AP-1 with estrogens. We discuss the possibility that a repressor interaction with the DBD both mediates the AF-independent pathway and dampens the AF dependent pathway. Mutations in the conserved lysine might, by this model, disrupt the binding or function of the repressor. PMID:15132742

  5. AP-1-Targeted Anti-Inflammatory Activities of the Nanostructured, Self-Assembling S5 Peptide

    PubMed Central

    Yang, Woo Seok; Son, Young-Jin; Kim, Mi-Yeon; Kim, Soochan; Kim, Jong-Hoon

    2015-01-01

    Peptide-based therapeutics have received increasing attention in medical research. However, the local delivery of such therapeutics poses unique challenges. Self-assembling peptides that use decorated nanofibers are one approach by which these therapeutics may be delivered. We previously found that the self-assembling K5 peptide affects the anti-inflammatory response. The aim of the present study was to investigate another self-assembling peptide, S5. Unlike the K5 peptide which has a positive charge, the S5 peptide has a free hydroxyl (-OH) group. We first examined whether the S5 peptide regulates the inflammatory response in primary cells and found that the S5 peptide reduced the production of prostaglandin E2 (PGE2) and tumor necrosis factor (TNF)-α in lipopolysaccharide- (LPS-) treated bone marrow-derived macrophages. Moreover, the S5 peptide significantly downregulated cyclooxygenase- (COX-) 2, TNF-α, and interleukin- (IL-) 1β expression by blocking the nuclear translocation of c-Jun. Consistent with this finding, the S5 peptide diminished the activation of inflammatory signaling enzymes related to p38. The S5 peptide also inhibited the formation of the p38/c-Jun signaling complex in RAW264.7 cells. Similarly, p38 and MKK3/6 were inhibited by the S5 peptide in LPS-activated peritoneal macrophages. Taken together, these results strongly suggest that the S5 peptide could exert anti-inflammatory effects by inhibiting the c-Jun/p38 signaling pathway. PMID:26074678

  6. Interaction of glucocorticoid receptor (GR) with estrogen receptor (ER) α and activator protein 1 (AP1) in dexamethasone-mediated interference of ERα activity.

    PubMed

    Karmakar, Sudipan; Jin, Yetao; Nagaich, Akhilesh K

    2013-08-16

    The role of glucocorticoids in the inhibition of estrogen (17-β-estradiol (E2))-regulated estrogen receptor (ER)-positive breast cancer cell proliferation is well established. We and others have seen that synthetic glucocorticoid dexamethasone (Dex) antagonizes E2-stimulated endogenous ERα target gene expression. However, how glucocorticoids negatively regulate the ERα signaling pathway is still poorly understood. ChIP studies using ERα- and glucocorticoid receptor (GR)-positive MCF-7 cells revealed that GR occupies several ERα-binding regions (EBRs) in cells treated with E2 and Dex simultaneously. Interestingly, there was little or no GR loading to these regions when cells were treated with E2 or Dex alone. The E2+Dex-dependent GR recruitment is associated with the displacement of ERα and steroid receptor coactivator-3 from the target EBRs leading to the repression of ERα-mediated transcriptional activation. The recruitment of GR to EBRs requires assistance from ERα and FOXA1 and is facilitated by AP1 binding within the EBRs. The GR binding to EBRs is mediated via direct protein-protein interaction between the GR DNA-binding domain and ERα. Limited mutational analyses indicate that arginine 488 located within the C-terminal zinc finger domain of the GR DNA-binding domain plays a critical role in stabilizing this interaction. Together, the results of this study unravel a novel mechanism involved in glucocorticoid inhibition of ERα transcriptional activity and E2-mediated cell proliferation and thus establish a foundation for future exploitation of the GR signaling pathway in the treatment of ER-positive breast cancer.

  7. Clinical Light Exposure, Photoreceptor Degeneration, and AP-1 Activation: A Cell Death or Cell Survival Signal in the Rhodopsin Mutant Retina?

    PubMed Central

    Gu, Danian; Beltran, William A.; Li, Zexiao; Acland, Gregory M.; Aguirre, Gustavo D.

    2008-01-01

    Purpose The T4R RHO mutant dog retina shows retinal degeneration with exposures to light comparable to those used in clinical eye examinations of patients. To define the molecular mechanisms of the degeneration, AP-1 DNA-binding activity, composition, posttranslational modification of the protein complex, and modulation of ERK/MAPK signaling pathways were examined in light-exposed mutant retinas. Methods Dark-adapted retinas were exposed to short-duration light flashes from a retinal camera used clinically for retinal photography and were collected at different time points after exposure. Electrophoretic mobility shift assay (EMSA), super-shift EMSA, Western blot analysis, and immunocytochemistry were used to examine AP-1 signaling. Results Exposure to light of mutant retinas significantly increased AP-1 DNA-binding activity by 1 hour after exposure, and levels remained elevated for 6 hours. Shielded mutant retinas had similar AP-1 levels to shielded or exposed wild-type retinas. The parallel phosphorylation of c-Fos and activation of ERK1/2 was detected only in exposed mutant retinas. Exposure to light changed the composition of the AP-1 protein complex in the mutant retina from c-Jun/Fra-1/c-Fos to JunB/c-Fos. Immunohistochemistry showed that the components of activated AP-1 (JunB, and phosphorylated c-Fos, and phosphorylated ERK1/2 isoforms) were localized in Müller cells. Conclusions The inner nuclear layer/Müller cell localization of the key proteins induced by light exposure raises the question of the direct involvement of AP-1 in mediating photoreceptor cell death in this model of autosomal dominant retinitis pigmentosa. PMID:17962438

  8. v-Src activates the expression of 92-kDa type IV collagenase gene through the AP-1 site and the GT box homologous to retinoblastoma control elements. A mechanism regulating gene expression independent of that by inflammatory cytokines.

    PubMed

    Sato, H; Kita, M; Seiki, M

    1993-11-05

    The 92-kDa type IV collagenase (matrix metalloproteinase-9; MMP-9) is frequently expressed in cells showing an invasive nature during physiological and pathological processes, and the expression is strictly controlled by a variety of trans-membrane signals. Binding sites for NF-kB, Sp-1, and AP-1 are reportedly required for induction of MMP-9 gene expression by tumor necrosis factor-alpha or 12-O-tetradecanoylphorbol-13-acetate. Comparison of the sequence of the newly cloned mouse MMP-9 promoter region with our previous human isolate revealed that, in addition to the above mentioned elements, four units of GGGG(T/A)GGGG sequence (GT box) were conserved between the two species. In this study, we have demonstrated that one of the GT boxes located downstream of the AP-1 site is essential along with the AP-1 site for the activation of the promoter by v-Src but not by tumor necrosis factor-alpha or 12-O-tetradecanoylphorbol-13-acetate. Gel mobility-shift assays revealed that binding proteins for retinoblastoma control element, including Sp-1 family protein, can bind specifically to GT boxes. Thus, the v-Src signals to the AP-1 site and to the GT box homologous to retinoblastoma control element acted synergistically in transcriptional activation. These results suggest that certain v-Src-mediated signals are propagated along pathways that are independent of inflammatory cytokines.

  9. Arctigenin, a phenylpropanoid dibenzylbutyrolactone lignan, inhibits MAP kinases and AP-1 activation via potent MKK inhibition: the role in TNF-alpha inhibition.

    PubMed

    Cho, Min Kyung; Jang, Young Pyo; Kim, Young Choong; Kim, Sang Geon

    2004-10-01

    Arctigenin, naturally occurring in Bardanae fructus, Saussurea medusa, Arctium lappa L., Torreya nucifera and Ipomea cairica, is a phenylpropanoid dibenzylbutyrolactone lignan with antioxidant and anti-inflammatory activities. Previously, we showed that arctigenin potently inhibited the induction of nitric oxide synthase (iNOS) by lipopolysaccharide (LPS), which involved suppression of NF-kappaB activation. In the present study, we examined the effects of arctigenin on mitogen-activated protein (MAP) kinase activation in Raw264.7 cells and MAP kinase kinase (MKK) activity. The effect of arctigenin on activator protein-1 (AP-1) activation was also studied in association with tumor necrosis factor-alpha (TNF-alpha) expression. Immunoblot analysis showed that arctigenin inhibited phosphorylation of MAP kinases ERK1/2, p38 kinase and JNK and their activities in Raw264.7 cells treated with LPS. Arctigenin potently inhibited the activity of MKK1 in vitro with the IC(50) value of 1 nM. Gel shift and reporter gene analyses revealed that arctigenin inhibited LPS-inducible AP-1 binding to the AP-1 consensus oligonucleotide and AP-1-mediated reporter gene expression. In view of the potential role of AP-1 in the induction of TNF-alpha, we next examined the inhibitory effects of arctigenin on the expression of TNF-alpha. Arctigenin blocked TNF-alpha production and decreased the level of TNF-alpha mRNA in the cells exposed to LPS. These results showed that arctigenin inhibited activation of MAP kinases including ERK1/2, p38 kinase and JNK through the inhibition of MKK activities, leading to AP-1 inactivation, which might, at least in part, contribute to the inhibition of TNF-alpha production.

  10. Iron, oxidative stress, and virulence: roles of iron-sensitive transcription factor Sre1 and the redox sensor ChAp1 in the maize pathogen Cochliobolus heterostrophus.

    PubMed

    Zhang, Ning; MohdZainudin, Nur A I; Scher, Keren; Condon, Bradford J; Horwitz, Benjamin A; Turgeon, B Gillian

    2013-12-01

    The gene SRE1, encoding the GATA transcription factor siderophore biosynthesis repressor (Sre1), was identified in the genome of the maize pathogen Cochliobolus heterostrophus and deleted. Mutants were altered in sensitivity to iron, oxidative stress, and virulence to the host. To gain insight into mechanisms of this combined regulation, genetic interactions among SRE1 (the nonribosomal peptide synthetase encoding gene NPS6, which is responsible for extracellular siderophore biosynthesis) and ChAP1 (encoding a transcription factor regulating redox homeostasis) were studied. To identify members of the Sre1 regulon, expression of candidate iron and oxidative stress-related genes was assessed in wild-type (WT) and sre1 mutants using quantitative reverse-transcription polymerase chain reaction. In sre1 mutants, NPS6 and NPS2 genes, responsible for siderophore biosynthesis, were derepressed under iron replete conditions, whereas the high-affinity reductive iron uptake pathway associated gene, FTR1, was not, in contrast to outcomes with other well-studied fungal models. C. heterostrophus L-ornithine-N(5)- monooxygenase (SIDA2), ATP-binding cassette (ABC6), catalase (CAT1), and superoxide dismutase (SOD1) genes were also derepressed under iron-replete conditions in sre1 mutants. Chap1nps6 double mutants were more sensitive to oxidative stress than either Chap1 or nps6 single mutants, while Chap1sre1 double mutants showed a modest increase in resistance compared with single Chap1 mutants but were much more sensitive than sre1 mutants. These findings suggest that the NPS6 siderophore indirectly contributes to redox homeostasis via iron sequestration, while Sre1 misregulation may render cells more sensitive to oxidative stress. The double-mutant phenotypes are consistent with a model in which iron sequestration by NPS6 defends the pathogen against oxidative stress. C. heterostrophus sre1, nps6, Chap1, Chap1nps6, and Chap1sre1 mutants are all reduced in virulence toward the

  11. LMP1-augmented kappa intron enhancer activity contributes to upregulation expression of Ig kappa light chain via NF-kappaB and AP-1 pathways in nasopharyngeal carcinoma cells

    PubMed Central

    Liu, HaiDan; Zheng, Hui; Duan, Zhi; Hu, DuoSha; Li, Ming; Liu, SuFang; Li, ZiJian; Deng, XiYun; Wang, ZhenLian; Tang, Min; Shi, Ying; Yi, Wei; Cao, Ya

    2009-01-01

    Background Expression of kappa gene is under the control of distinct cis-regulatory elements, including the kappa intron enhancer (iEκ) and the kappa 3' enhancer (3'Eκ). The active enhancers and expression of immunoglobulin is generally considered to be restricted to B lymphocytes. However, accumulating evidence indicated that epithelial cancer cells, including nasopharyngeal carcinoma (NPC) cell lines, express immunoglobulins. The mechanisms underlying the expression of Igs in nonlymphoid cells remain unknown. On the basis of our previous finding that expression of kappa light chain in NPC cells can be upregulated by EBV-encoded latent membrane protein 1(LMP1) through the activation of NF-κB and AP-1 signaling pathways, we thus use NPC cells as model to further explore the molecular mechanisms of nonlymphoid cells expressing Ig kappa. Results In this study, luciferase reporter plasmid containing human wild-type iEκ, and its derivative plasmids containing mutant binding sites for transcription factor NF-κB or AP-1 were constructed. Luciferase reporter assays demonstrate iEκ is active in Igκ-expressing NPC cells and LMP1 expression can upregulate the activity of iEκ in NPC cells. Mutation of the NF-κB or AP-1 site within and downstream the iEκ, inhibition of the NF-κB and AP-1 pathways by their respective chemical inhibitor Bay11-7082 and SP600125 as well as stable or transient expression of dominant-negative mutant of IκBα (DNMIκBα) or of c-Jun (TAM67) indicate that both sites are functional and LMP1-enhanced iEκ activity is partly regulated by these two sites. Gel shift assays show that LMP1 promotes NF-κB subunits p52 and p65 as well as AP-1 family members c-Jun and c-Fos binding to the κNF-κB and the κAP-1 motifs in vitro, respectively. Both chemical inhibitors and dominant negative mutants targeting for NF-κB and AP-1 pathways can attenuate the LMP1-enhanced bindings. Co-IP assays using nuclear extracts from HNE2-LMP1 cells reveal that p52

  12. cAMP-responsive Element-binding Protein (CREB) and cAMP Co-regulate Activator Protein 1 (AP1)-dependent Regeneration-associated Gene Expression and Neurite Growth*

    PubMed Central

    Ma, Thong C.; Barco, Angel; Ratan, Rajiv R.; Willis, Dianna E.

    2014-01-01

    To regenerate damaged axons, neurons must express a cassette of regeneration-associated genes (RAGs) that increases intrinsic growth capacity and confers resistance to extrinsic inhibitory cues. Here we show that dibutyrl-cAMP or forskolin combined with constitutive-active CREB are superior to either agent alone in driving neurite growth on permissive and inhibitory substrates. Of the RAGs examined, only arginase 1 (Arg1) expression correlated with the increased neurite growth induced by the cAMP/CREB combination, both of which were AP1-dependent. This suggests that cAMP-induced AP1 activity is necessary and interacts with CREB to drive expression of RAGs relevant for regeneration and demonstrates that combining a small molecule (cAMP) with an activated transcription factor (CREB) stimulates the gene expression necessary to enhance axonal regeneration. PMID:25296755

  13. Molecular Mechanisms of Natural Honey Against H. pylori Infection Via Suppression of NF-κB and AP-1 Activation in Gastric Epithelial Cells.

    PubMed

    Abdel-Latif, Mohamed M M; Abouzied, Mekky M

    2016-07-01

    Natural honey has been used as a medicine since ancient times. Honey is widely known for its antibacterial properties against H. pylori; however, the mechanisms of its antibacterial activity are not fully known. The present study was performed to examine the molecular mechanisms by which natural honey can inhibit H. pylori infection in gastric epithelial cells. Electrophoretic mobility shift assay was used to measure NF-κB- and AP-1-DNA binding activity. Western blotting was used to detect IκB-α and COX-2 expression. H. pylori induced NF-κB and AP-1 DNA-binding activity in gastric epithelial cells. Manuka honey inhibited H. pylori-induced NF-κB and AP-1 in a time- and dose-dependent manner. Maximum inhibition of H. pylori-induced NF-κB and AP-1 by manuka honey was observed at concentrations of 20% at 1-2 h. Pre-treatment of AGS cells with other commercial natural honeys also inhibited H. pylori-induced NF-κB and AP-1 DNA-binding activity. Honey prevented H. pylori-induced degradation of IκB-α protein and downregulated COX-2 protein levels. Our findings suggest that natural honey exerts its inhibitory effects against H. pylori by inhibiting NF-κB and AP-1 activation and downregulation of COX-2 expression. These results provide new mechanistic insights into honey effects in the suppression of H. pylori infection. Copyright © 2016 IMSS. Published by Elsevier Inc. All rights reserved.

  14. Relative Antioxidant Activities of Quercetin and Its Structurally Related Substances and Their Effects on NF-κB/CRE/AP-1 Signaling in Murine Macrophages

    PubMed Central

    Kim, Byung-Hak; Choi, Jung Sook; Yi, Eun Hee; Lee, Jin-Ku; Won, Cheolhee; Ye, Sang-Kyu; Kim, Myoung-Hwan

    2013-01-01

    Reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced by the oxidative burst in activated macrophages and neutrophils cause oxidative stress-implicated diseases. Quercetin is flavonoid that occurs naturally in plants and is widely used as a nutritional supplement due to its antioxidant and anti-inflammatory properties. In this study, we investigated antioxidant activities and mechanisms of action in zymosan-induced macrophages of quercetin and quercetin-related flavonoids such as quercitrin, isoquercitrin, quercetin 3-O-β-(2″-galloyl)-rhamnopyranoside (QGR) and quercetin 3-O-β-(2″-galloyl)-glucopyranoside (QGG) as well as gallic acid, a building moiety of QGR and QGG. QGR and QGG exhibited stronger antioxidant activities compared with quercetin, whereas quercitrin, isoquercitrin and gallic acid exhibited weak-to-no antioxidant activities, assessed by 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, superoxide production, superoxide scavenging, nitric oxide (NO) production, peroxynitrite (ONOO−) scavenging and myeloperoxidase (MPO) activity. Regarding mechanisms, the quercetin-containing flavonoids QGR and QGG differentially targeted compared with quercetin in the NF-κB signaling pathway that inhibited the DNA binding activity of the NF-κB complex without affecting the degradation and phosphorylation of IκBα and NF-κB phosphorylation. In addition, QGR and QGG inhibited CRE and activator protein (AP-1) transcriptional activity and JNK phosphorylation by inhibiting the cAMP/protein kinase A (PKA) and protein kinase C (PKC) signaling in a different manner than quercetin. Our results showed that although QGR and QGG exhibited stronger antioxidant activities than quercetin in macrophages, their mechanisms of action in terms of the NF-κB, PKA and PKC signaling pathways were different. PMID:23649461

  15. The role of AP-1 and epigenetics in ALCL.

    PubMed

    Schiefer, Ana-Iris; Vesely, Paul; Hassler, Melanie R; Egger, Gerda; Kenner, Lukas

    2015-06-01

    Anaplastic large cell lymphoma (ALCL) is an aggressive, highly proliferative, T-cell lymphoma with increasing incidence worldwide. Anaplastic Lymphoma Kinase (ALK) fusions occur in about 50% of all cases. Most ALK positive cases of ALCL harbor the t(2;5) translocation that leads to expression of Nucleophosmin-Anaplastic Lymphoma Kinase (NPM-ALK). NPM-ALK induces a variety of oncogenic signaling pathways that lead to malignant transformation of T-cells via Activator Protein-1 (AP-1), STAT3 and other (transcription) factors. In addition to the commonly known AP-1 activators Mitogen-Activated Protein Kinases (MAPKs), there are other signaling pathways, such as PI3K/mTOR/AKT, which are implicated in AP-1 activation/expression in ALCL. The AP-1 factor JUNB was shown to drive ALCL proliferation and the expression of the characteristic ALCL Ki-1 antigen, CD30. cJUN and JUNB target PDGFRB, thereby leading to tumor progression and dissemination. Furthermore, aberrant gene expression in ALCL is frequently accompanied by changes in epigenetic regulatory mechanisms, such as DNA methylation patterns. Here, we discuss the role of AP-1 in the pathogenesis of ALCL and provide an overview of pathological epigenetic changes in ALCL cells.

  16. CREB and AP-1 activation regulates MKP-1 induction by LPS or M-CSF and their kinetics correlate with macrophage activation versus proliferation.

    PubMed

    Casals-Casas, Cristina; Alvarez, Eva; Serra, Maria; de la Torre, Carolina; Farrera, Consol; Sánchez-Tilló, Ester; Caelles, Carme; Lloberas, Jorge; Celada, Antonio

    2009-07-01

    MAPK phosphatase-1 (MKP-1) is a protein phosphatase that plays a crucial role in innate immunity. This phosphatase inactivates ERK1/2, which are involved in two opposite functional activities of the macrophage, namely proliferation and activation. Here we found that although macrophage proliferation and activation induce MKP-1 with different kinetics, gene expression is mediated by the proximal promoter sequences localized between -380 and -180 bp. Mutagenesis experiments of the proximal element determined that CRE/AP-1 is required for LPS- or M-CSF-induced activation of the MKP-1 gene. Moreover, the results from gel shift analysis and chromatin immunoprecipitation indicated that c-Jun and CREB bind to the CRE/AP-1 box. The distinct kinetics shown by M-CSF and LPS correlates with the induction of JNK and c-jun, as well as the requirement for Raf-1. The signal transduction pathways that activate the induction of MKP-1 correlate kinetically with induction by M-CSF and LPS.

  17. Two peptides, TsAP-1 and TsAP-2, from the venom of the Brazilian yellow scorpion, Tityus serrulatus: evaluation of their antimicrobial and anticancer activities.

    PubMed

    Guo, Xiaoxiao; Ma, Chengbang; Du, Qiang; Wei, Ran; Wang, Lei; Zhou, Mei; Chen, Tianbao; Shaw, Chris

    2013-09-01

    Here we report two novel 17-mer amidated linear peptides (TsAP-1 and TsAP-2) whose structures were deduced from cDNAs cloned from a venom-derived cDNA library of the Brazilian yellow scorpion, Tityus serrulatus. Both mature peptides were structurally-characterised following their location in chromatographic fractions of venom and synthetic replicates of each were subjected to a range of biological assays. The peptides were each active against model test micro-organisms but with different potencies. TsAP-1 was of low potency against all three test organisms (MICs 120-160 μM), whereas TsAP-2 was of high potency against the Gram-positive bacterium, Staphylococcus aureus (MIC 5 μM) and the yeast, Candida albicans (10 μM). Haemolytic activity of TsAP-1 was low (4% at 160 μM) and in contrast, that of TsAP-2 was considerably higher (18% at 20 μM). Substitution of four neutral amino acid residues with Lys residues in each peptide had dramatic effects on their antimicrobial potencies and haemolytic activities, particularly those of TsAP-1. The MICs of the enhanced cationic analogue (TsAP-S1) were 2.5 μM for S. aureus/C. albicans and 5 μM for E. coli but with an associated large increase in haemolytic activity (30% at 5 μM). The same Lys residue substitutions in TsAP-2 produced a dramatic effect on its MIC for E. coli lowering this from >320 μM to 5 μM. TsAP-1 was ineffective against three of the five human cancer cell lines tested while TsAP-2 inhibited the growth of all five. Lys residue substitution of both peptides enhanced their potency against all five cell lines with TsAp-S2 being the most potent with IC50 values ranging between 0.83 and 2.0 μM. TsAP-1 and TsAP-2 are novel scorpion venom peptides with broad spectrum antimicrobial and anticancer cell activities the potencies of which can be significantly enhanced by increasing their cationicity.

  18. The RNA-binding protein RBPMS1 represses AP-1 signaling and regulates breast cancer cell proliferation and migration.

    PubMed

    Fu, Jie; Cheng, Long; Wang, Yu; Yuan, Ping; Xu, Xiaojie; Ding, Lihua; Zhang, Hao; Jiang, Kai; Song, Haifeng; Chen, Zhongwu; Ye, Qinong

    2015-01-01

    The activator protein-1 (AP-1) transcription factor complex plays a crucial role in tumor growth and progression. However, how AP-1 transcriptional activity is repressed is not fully understood. Here, we show that RNA-binding protein with multiple splicing 1 (RBPMS1) physically and functionally interacts with AP-1 in vitro and in vivo. The RNA-recognition motif (RRM) and C-terminus of the RBPMS1 isoforms RBPMS1A and RBPMS1C, but not RBPMS1B, interacted with cFos, a member of the AP-1 family that dimerizes with cJun to stimulate AP-1 transcriptional activity. RBPMS1 did not associate with Jun proteins. RBPMS1A and RBPMS1C bound to the basic leucine zipper (bZIP) domain of cFos that mediates dimerization of AP-1 proteins. In addition, RBPMS1A-C interacted with the transcription factor Smad3, which was shown to interact with cJun and increase AP-1 transcriptional activity. RBPMS1 inhibited c-Fos or Smad3-mediated AP-1 transactivation and the expression of AP-1 target genes known to be the key regulators of cancer growth and progression, including vascular endothelial growth factor (VEGF) and cyclin D1. Mechanistically, RBPMS1 blocks the formation of the cFos/cJun or Smad3/cJun complex as well as the recruitment of cFos or Smad3 to the promoters of AP-1 target genes. In cultured cells and a mouse xenograft model, RBPMS1 inhibited the growth and migration of breast cancer cells through c-Fos or Smad3. These data suggest that RBPMS1 is a critical repressor of AP-1 signaling and RBPMS1 activation may be a useful strategy for cancer treatment.

  19. A novel synthetic derivative of the natural product berbamine inhibits cell viability and induces apoptosis of human osteosarcoma cells, associated with activation of JNK/AP-1 signaling.

    PubMed

    Yang, Fan; Nam, Sangkil; Zhao, Robin; Tian, Yan; Liu, Lucy; Horne, David A; Jove, Richard

    2013-11-01

    Osteosarcoma is the most common primary bone tumor in children and adolescents. There is a critical need to find more potent drugs for patients with metastatic or recurrent disease. Berbamine (BBM) is a natural compound derived from the Berberis amurensis plants. BBM and its derivatives have been shown to have antitumor effects in several cancers. Here, we report that a novel synthetic berbamine derivative, BBMD3, inhibits cell viability and induces apoptosis of G292, KHOS, and MG-63 human osteosarcoma cells. Induction of apoptosis in these tumor cells depends on activation of caspase-3 and cleavage of poly(ADP-ribose) polymerase (PARP). Since pan-caspase inhibitor (Z-VAD-FMK) and caspase-9 inhibitor (Z-LEHD-FMK) could block the cleavage of PARP, the apoptosis induced by BBMD3 is through intrinsic signaling pathway. BBMD3 increased phosphorylation of c-Jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK), resulting in increase of phosphorylated c-Jun and total c-Fos, the major components of transcriptional factor AP-1. JNK inhibitor could partially suppress antitumor effect of BBMD3 on osteosarcoma cells. BBMD3 increased the production of reactive oxygen species (ROS) and ROS scavenger, N-acetylcysteine (NAC), could block the phosphorylation of JNK and c-Jun induced by BBMD3. BBMD3 increased the expression of the pro-apototic gene Bad, associated with apoptosis induction. Finally, BBMD3 also decreased the expression of cyclin D1 and D2, the positive cell cycle regulators, which is correlated with growth inhibition in osteosarcoma cells. Collectively, these findings indicate that BBMD3 is a potentially promising drug for the treatment of human osteosarcoma.

  20. Src Tyrosine Kinase Activation by 4-Hydroxynonenal Upregulates p38, ERK/AP-1 Signaling and COX-2 Expression in YPEN-1 Cells.

    PubMed

    Jang, Eun Ji; Jeong, Hyoung Oh; Park, Daeui; Kim, Dae Hyun; Choi, Yeon Ja; Chung, Ki Wung; Park, Min Hi; Yu, Byung Pal; Chung, Hae Young

    2015-01-01

    4-Hydroxynonenal (4-HNE), a major end product of lipid peroxidation, is highly reactive and involved in various cellular processes, such as inflammatory signaling. However, to date, the mechanistic roles of 4-HNE in inflammatory signaling related to protein tyrosine kinases have not been elucidated. In the present study, we investigated the interaction between 4-HNE and Src (a non-receptor tyrosine kinase) for its involvement in the molecular modulation of the inflammatory signaling pathway utilizing the YPEN-1 cell system. Immunoprecipitation experiments showed that 4-HNE phosphorylates (activates) Src at Tyr416 via adduct formation. In addition, LC-MS/MS and a docking simulation model revealed an addiction site at the Cys248 residue of Src, resulting in the stimulation of downstream p38, ERK/AP-1 and cyclooxygenase-2 (COX-2) signaling in YPEN-1 cells. The role of 4-HNE-activated Src in downstream inflammatory signaling was further investigated using dasatinib (a Src inhibitor) and by siRNA knockdown of Src. p38 and ERK were directly regulated by Src, as revealed by immunoblotting of the phosphorylated forms of mitogen-activated protein kinases (MAPKs), which are key elements in the signaling transduction pathway initiated by Src. The study also shows that Src modulates the HNE-enhanced activation of AP-1 and the expression of COX-2 (a target gene of AP-1). Together, the results of this study show that 4-HNE stimulates Src tyrosine kinase in activation of the inflammation process.

  1. Inactivation of AP1 proteins by a nuclear serine protease precedes the onset of radiation-induced fibrosing alveolitis.

    PubMed

    Haase, Michael G; Klawitter, Anke; Bierhaus, Angelika; Yokoyama, Kazunari K; Kasper, Michael; Geyer, Peter; Baumann, Michael; Baretton, Gustavo B

    2008-05-01

    Radiation-induced lung damage comprises inflammation (alveolitis) as well as disturbed regulation of cell differentiation and proliferation (fibrosis). The transcriptional regulation of this process is poorly understood. One key transcription factor involved in the regulation of proliferation and differentiation is AP1 (activator protein 1). The present study examined changes in the DNA-binding activity of AP1 after irradiation and defined the underlying molecular mechanisms in an animal model. The right lungs of Fischer rats received a single radiation dose of 20 Gy. Lung tissue was tested for AP1 DNA-binding activity, AP1 mRNA, and levels of AP1 proteins as well as for c-Jun specific proteolytic activity. After an initial increase, the AP1 DNA-binding activity was completely lost starting at 5.5 weeks after irradiation, which is 2.5 weeks before the onset of fibrosing alveolitis. This was not caused by reduction of mRNA levels or size. Instead, a selective nuclear cleavage of c-Jun by a serine protease caused the loss of AP1 activity. Considering the central role of AP1 in cell proliferation and differentiation and the strict timely correlation to the onset of the disease, the complete loss of AP1 function is likely to play a critical role in radiation-induced fibrosing alveolitis.

  2. AP-1 is involved in ICOS gene expression downstream of TCR/CD28 and cytokine receptor signaling.

    PubMed

    Watanabe, Masashi; Nakajima, Shinsuke; Ohnuki, Kazunobu; Ogawa, Shuhei; Yamashita, Masakatsu; Nakayama, Toshinori; Murakami, Yasufumi; Tanabe, Kazunari; Abe, Ryo

    2012-07-01

    It has been proposed that sustained ICOS expression in chronic inflammatory immune conditions, such as autoimmunity and allergy, contributes to symptom exacerbation. Therefore modulation of ICOS gene expression could be a potential therapeutic strategy for such immune diseases. However, the precise molecular mechanisms controlling ICOS gene expression remain poorly understood. In this study, we explored transcription factors involving in ICOS gene expression and examined their roles in a physiological situation. Microarray analysis revealed that one AP-1 molecule, Fos-related antigen-2 (Fra2), was highly correlated with ICOS expression. Ectopic expression of Fra2 and other AP-1 molecules upregulated ICOS expression on T cells. We identified an AP-1-responsive site (AP1-RE) within the ICOS promoter region and demonstrated AP-1 actually binds to AP1-RE upon TCR/CD28 stimulation. Meanwhile, we found several cytokines could upregulate ICOS expression on both naïve and effector T cells in a manner independent of TCR/CD28 stimulation. These cytokine stimuli induced AP-1 binding to AP1-RE. Together, our results indicate AP-1 transcription factors are involved in ICOS gene expression downstream of both TCR/CD28 signaling and cytokine receptor signaling, and suggest AP-1 activation via cytokine receptor signaling may be one of the mechanisms maintaining high level ICOS expression in chronic inflammatory immune responses.

  3. AP-1 family members act with Sox9 to promote chondrocyte hypertrophy.

    PubMed

    He, Xinjun; Ohba, Shinsuke; Hojo, Hironori; McMahon, Andrew P

    2016-08-15

    An analysis of Sox9 binding profiles in developing chondrocytes identified marked enrichment of an AP-1-like motif. Here, we have explored the functional interplay between Sox9 and AP-1 in mammalian chondrocyte development. Among AP-1 family members, Jun and Fosl2 were highly expressed within prehypertrophic and early hypertrophic chondrocytes. Chromatin immunoprecipitation followed by DNA sequencing (ChIP-seq) showed a striking overlap in Jun- and Sox9-bound regions throughout the chondrocyte genome, reflecting direct binding of each factor to the same enhancers and a potential for protein-protein interactions within AP-1- and Sox9-containing complexes. In vitro reporter analysis indicated that direct co-binding of Sox9 and AP-1 at target motifs promoted gene activity. By contrast, where only one factor can engage its DNA target, the presence of the other factor suppresses target activation consistent with protein-protein interactions attenuating transcription. Analysis of prehypertrophic chondrocyte removal of Sox9 confirmed the requirement of Sox9 for hypertrophic chondrocyte development, and in vitro and ex vivo analyses showed that AP-1 promotes chondrocyte hypertrophy. Sox9 and Jun co-bound and co-activated a Col10a1 enhancer in Sox9 and AP-1 motif-dependent manners consistent with their combined action promoting hypertrophic gene expression. Together, the data support a model in which AP-1 family members contribute to Sox9 action in the transition of chondrocytes to the hypertrophic program.

  4. Advanced glycation end products upregulate lysyl oxidase and endothelin-1 in human aortic endothelial cells via parallel activation of ERK1/2-NF-κB and JNK-AP-1 signaling pathways.

    PubMed

    Adamopoulos, Christos; Piperi, Christina; Gargalionis, Antonios N; Dalagiorgou, Georgia; Spilioti, Eliana; Korkolopoulou, Penelope; Diamanti-Kandarakis, Evanthia; Papavassiliou, Athanasios G

    2016-04-01

    Endothelial dysfunction involves deregulation of the key extracellular matrix (ECM) enzyme lysyl oxidase (LOX) and the vasoconstrictor protein, endothelin-1 (ET-1), whose gene expression can be modulated by the transcriptional activators nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1). Advanced glycation end products (AGEs) present an aggravating factor of endothelial dysfunction which upon engagement to their receptor RAGE induce upregulation of mitogen-activated protein kinases (MAPKs), leading to NF-κB and AP-1 potentiation. We hypothesized that AGEs could induce NF-κΒ- and AP-1-dependent regulation of LOX and ET-1 expression via the AGE/RAGE/MAPK signaling axis. Western blot, real-time qRT-PCR, FACS analysis and electrophoretic mobility-shift assays were employed in human aortic endothelial cells (HAECs) following treatment with AGE-bovine serum albumin (AGE-BSA) to investigate the signaling pathway towards this hypothesis. Furthermore, immunohistochemical analysis of AGEs, RAGE, LOX and ET-1 expression was conducted in aortic endothelium of a rat experimental model exposed to high- or low-AGE content diet. HAECs exposed to AGE-BSA for various time points exhibited upregulation of LOX and ET-1 mRNA levels in a dose- and time-dependent manner. Exposure of HAECs to AGE-BSA also showed specific elevation of phospho(p)-ERK1/2 and p-JNK levels in a dose- and time-dependent fashion. AGE administration significantly increased NF-κΒ- and AP-1-binding activity to both LOX and ET-1 cognate promoter regions. Moreover, LOX and ET-1 overexpression in rat aortic endothelium upon high-AGE content diet confirmed the functional interrelation of these molecules. Our findings demonstrate that AGEs trigger NF-κΒ- and AP-1-mediated upregulation of LOX and ET-1 via the AGE/RAGE/MAPK signaling cascade in human endothelial cells, thus contributing to distorted endothelial homeostasis by impairing endothelial barrier function, altering ECM biomechanical properties

  5. A novel tribasic Golgi export signal directs cargo protein interaction with activated Rab11 and AP-1-dependent Golgi-plasma membrane trafficking.

    PubMed

    Parmar, Hirendrasinh B; Duncan, Roy

    2016-04-15

    The reovirus fusion-associated small transmembrane (FAST) proteins comprise a unique family of viral membrane fusion proteins dedicated to inducing cell-cell fusion. We recently reported that a polybasic motif (PBM) in the cytosolic tail of reptilian reovirus p14 FAST protein functions as a novel tribasic Golgi export signal. Using coimmunoprecipitation and fluorescence resonance energy transfer (FRET) assays, we now show the PBM directs interaction of p14 with GTP-Rab11. Overexpression of dominant-negative Rab11 and RNA interference knockdown of endogenous Rab11 inhibited p14 plasma membrane trafficking and resulted in p14 accumulation in the Golgi complex. This is the first example of Golgi export to the plasma membrane that is dependent on the interaction of membrane protein cargo with activated Rab11. RNA interference and immunofluorescence microscopy further revealed that p14 Golgi export is dependent on AP-1 (but not AP-3 or AP-4) and that Rab11 and AP-1 both colocalize with p14 at the TGN. Together these results imply the PBM mediates interactions of p14 with activated Rab11 at the TGN, resulting in p14 sorting into AP1-coated vesicles for anterograde TGN-plasma membrane transport.

  6. ERK-associated changes of AP-1 proteins during fear extinction.

    PubMed

    Guedea, Anita L; Schrick, Christina; Guzman, Yomayra F; Leaderbrand, Katie; Jovasevic, Vladimir; Corcoran, Kevin A; Tronson, Natalie C; Radulovic, Jelena

    2011-06-01

    Extensive research has unraveled the molecular basis of learning processes underlying contextual fear conditioning, but the mechanisms of fear extinction remain less known. Contextual fear extinction occurs when an aversive stimulus that initially caused fear is no longer present and depends on the activation of the extracellular signal-regulated kinase (ERK), among other molecules. Here we investigated how ERK signaling triggered by extinction affects its downstream targets belonging to the activator protein-1 (AP-1) transcription factor family. We found that extinction, when compared to conditioning of fear, markedly enhanced the interactions of active, phospho-ERK (pERK ) with c-Jun causing alterations of its phosphorylation state. The AP-1 binding of c-Jun was decreased whereas AP-1 binding of JunD, Jun dimerization protein 2 (JDP2) and ERK were significantly enhanced. The increased AP-1 binding of the inhibitory JunD and JDP2 transcription factors was paralleled by decreased levels of the AP-1 regulated proteins c-Fos and GluR2. These changes were specific for extinction and were MEK-dependent. Overall, fear extinction involves ERK/Jun interactions and a decrease of a subset of AP-1-regulated proteins that are typically required for fear conditioning. Facilitating the formation of inhibitory AP-1 complexes may thus facilitate the reduction of fear.

  7. Binding site specificity and factor redundancy in activator protein-1-driven human papillomavirus chromatin-dependent transcription.

    PubMed

    Wang, Wei-Ming; Wu, Shwu-Yuan; Lee, A-Young; Chiang, Cheng-Ming

    2011-11-25

    Activator protein-1 (AP-1) regulates diverse gene responses triggered by environmental cues and virus-induced cellular stress. Although many signaling events leading to AP-1 activation have been described, the fundamental features underlying binding site selection and factor recruitment of dimeric AP-1 complexes to their target genes remain mostly uncharacterized. Using recombinant full-length human AP-1 dimers formed between c-Jun and Fos family members (c-Fos, FosB, Fra-1, Fra-2) for DNA binding and transcriptional analysis, we found that each of these AP-1 complex exhibits differential activity for distinct non-consensus AP-1 sites present in human papillomavirus (HPV), and each AP-1 complex is capable of activating transcription from in vitro-reconstituted HPV chromatin in a p300- and acetyl-CoA-dependent manner. Transcription from HPV chromatin requires AP-1-dependent and contact-driven recruitment of p300. Acetylation of dimeric AP-1 complexes by p300 enhances AP-1 binding to DNA. Using a human C-33A cervical cancer-derived cell line harboring the episomal HPV type 11 genome, we illustrate binding site selectivity recognized by c-Jun, JunB, JunD, and various Fos family members in a combinatorial and unique pattern, highlighting the diversity and importance of non-canonical binding site recognition by various AP-1 family proteins.

  8. AP1 enhances polyomavirus DNA replication by promoting T-antigen-mediated unwinding of DNA.

    PubMed Central

    Guo, W; Tang, W J; Bu, X; Bermudez, V; Martin, M; Folk, W R

    1996-01-01

    An early step in the initiation of polyomavirus DNA replication is viral large-T-antigen-mediated unwinding of the origin. We report that components of the AP1 transcription factor, Fos and Jun, interact with T antigen in vitro to enhance unwinding of the viral origin. This provides a biochemical basis for the capacity of AP1 to activate viral DNA replication in vivo. PMID:8763994

  9. Synaptic and genomic responses to JNK and AP-1 signaling in Drosophila neurons

    PubMed Central

    Etter, Paul D; Narayanan, Radhakrishnan; Navratilova, Zaneta; Patel, Chirag; Bohmann, Dirk; Jasper, Heinrich; Ramaswami, Mani

    2005-01-01

    Background The transcription factor AP-1 positively controls synaptic plasticity at the Drosophila neuromuscular junction. Although in motor neurons, JNK has been shown to activate AP-1, a positive regulator of growth and strength at the larval NMJ, the consequences of JNK activation are poorly studied. In addition, the downstream transcriptional targets of JNK and AP-1 signaling in the Drosophila nervous system have yet to be identified. Here, we further investigated the role of JNK signaling at this model synapse employing an activated form of JNK-kinase; and using Serial Analysis of Gene Expression and oligonucleotide microarrays, searched for candidate early targets of JNK or AP-1 dependent transcription in neurons. Results Temporally-controlled JNK induction in postembryonic motor neurons triggers synaptic growth at the NMJ indicating a role in developmental plasticity rather than synaptogenesis. An unexpected observation that JNK activation also causes a reduction in transmitter release is inconsistent with JNK functioning solely through AP-1 and suggests an additional, yet-unidentified pathway for JNK signaling in motor neurons. SAGE profiling of mRNA expression helps define the neural transcriptome in Drosophila. Though many putative AP-1 and JNK target genes arose from the genomic screens, few were confirmed in subsequent validation experiments. One potentially important neuronal AP-1 target discovered, CG6044, was previously implicated in olfactory associative memory. In addition, 5 mRNAs regulated by RU486, a steroid used to trigger conditional gene expression were identified. Conclusion This study demonstrates a novel role for JNK signaling at the larval neuromuscular junction and provides a quantitative profile of gene transcription in Drosophila neurons. While identifying potential JNK/AP-1 targets it reveals the limitations of genome-wide analyses using complex tissues like the whole brain. PMID:15932641

  10. Chemokine Receptor 7 (CCR7) Gene Expression Is Regulated by NF-κB and Activator Protein 1 (AP1) in Metastatic Squamous Cell Carcinoma of Head and Neck (SCCHN)*

    PubMed Central

    Mburu, Yvonne K.; Egloff, Ann Marie; Walker, William H.; Wang, Lin; Seethala, Raja R.; van Waes, Carter; Ferris, Robert L.

    2012-01-01

    The chemokine receptor CCR7 is a seven-transmembrane domain G-protein-coupled receptor that facilitates leukocyte migration to regional lymph nodes. Aberrant CCR7 expression in a number of human malignancies has been linked to pro-survival, -invasive, and -metastatic pathways. We demonstrate here that up-regulation of CCR7 in squamous cell carcinoma of the head and neck (SCCHN) patient tumors correlates with lower survival because of metastatic disease. Because of this important oncogenic phenotype, we investigated the mechanisms that regulate CCR7 expression in these tumors. Interestingly, the inflammatory transcription factor NF-κB has been associated with a more aggressive SCCHN phenotype. Immunohistochemical staining of a SCCHN tumor cohort (n = 47) strongly linked NF-κB staining and CCR7 expression in SCCHN. Thus, we investigated whether NF-κB contributes to metastatic disease by promoting CCR7 expression in SCCHN tumor cells. We characterized four novel, potential NF-κB binding sites in the 1000-bp promoter region upstream of the CCR7 gene, using luciferase, ChIP, and EMSA. However, NF-κB inhibition only resulted in partial reduction in CCR7 expression, prompting consideration of other co-regulators of CCR7. Indeed, cooperation between NF-κB and AP1 transcription factors, which are often co-activated, is crucial to the regulation of CCR7 mRNA expression in metastatic SCCHN cells. Thus, our findings support an important biological role for inflammatory NF-κB and AP1 in the regulation of CCR7 expression in metastatic SCCHN. As such, CCR7, NF-κB, and AP1 could be potentially useful therapeutic targets in controlling the progression and metastasis of SCCHN tumors. PMID:22158872

  11. Interleukin-18 induces EMMPRIN expression in primary cardiomyocytes via JNK/Sp1 signaling and MMP-9 in part via EMMPRIN and through AP-1 and NF-κB activation

    PubMed Central

    Reddy, Venkatapuram Seenu; Prabhu, Sumanth D.; Mummidi, Srinivas; Valente, Anthony J.; Venkatesan, Balachandar; Shanmugam, Prakashsrinivasan; Delafontaine, Patrice

    2010-01-01

    IL-18 and the extracellular matrix metalloproteinase (MMP) inducer (EMMPRIN) stimulate the expression of proinflammatory cytokines and MMPs and are elevated in myocardial hypertrophy, remodeling, and failure. Here, we report several novel findings in primary cardiomyocytes treated with IL-18. First, IL-18 activated multiple transcription factors, including NF-κB (p50 and p65), activator protein (AP)-1 (cFos, cJun, and JunD), GATA, CCAAT/enhancer-binding protein, myocyte-specific enhancer-binding factor, interferon regulatory factor-1, p53, and specific protein (Sp)-1. Second, IL-18 induced EMMPRIN expression via myeloid differentiation primary response gene 88/IL-1 receptor-associated kinase/TNF receptor-associated factor-6/JNK-dependent Sp1 activation. Third, IL-18 induced a number of MMP genes, particularly MMP-9, at a rapid rate as well as tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-3 at a slower rate. Finally, the IL-18 induction of MMP-9 was mediated in part via EMMPRIN and through JNK- and ERK-dependent AP-1 activation and p38 MAPK-dependent NF-κB activation. These results suggest that the elevated expression of IL-18 during myocardial injury and inflammation may favor EMMPRIN and MMP induction and extracellular matrix degradation. Therefore, targeting IL-18 or its signaling pathways may be of potential therapeutic benefit in adverse remodeling. PMID:20693392

  12. Excretory-secretory products of Giardia lamblia induce interleukin-8 production in human colonic cells via activation of p38, ERK1/2, NF-κB and AP-1.

    PubMed

    Lee, H-Y; Hyung, S; Lee, N Y; Yong, T-S; Han, S-H; Park, S-J

    2012-04-01

    Giardia lamblia, a pathogen causing diarrhoeal outbreaks, is interesting how it triggers immune response in the human epithelial cells. This study defined the crucial roles of signalling components involved in G. lamblia-induced cytokine production in human epithelial cells. Incubation of the gastrointestinal cell line HT-29 with G. lamblia GS trophozoites triggered production of interleukin (IL)-1β, IL-8 and tumour necrosis factor (TNF)-α. IL-8 production was not significantly decreased by physically separating the HT-29 cells and G. lamblia GS trophozoites. Indeed, treatment of HT-29 with G. lamblia excretory-secretory products (ESP) induced IL-8 production. Electrophoretic mobility gel shift and transfection assays using mutagenized IL-8 promoter reporter plasmids indicated that IL-8 production by G. lamblia ESP occurs through activation of two transcriptional factors, nuclear factor kappaB (NF-κB) and activator protein 1 (AP-1) in HT-29 cells. In addition, activation of two mitogen-activated protein kinases (MAPKs), p38 and ERK1/2, was also detected in the HT-29 cells stimulated with G. lamblia ESP. Selective inhibition of these MAPKs resulted in decreased production of ESP-induced IL-8. These results indicate that activation of p38, ERK1/2 MAPK, NF-κB and AP-1 comprises the signalling pathway responsible for IL-8 production by G. lamblia ESP.

  13. Two tobacco AP1-like gene promoters with highly specific, tightly regulated and uniquely expressed activity during floral transition, initiation and development

    USDA-ARS?s Scientific Manuscript database

    Biotech engineering of agronomic traits requires an array of highly specific and tightly regulated promoters in flower or other tissues. In this study, we isolated and characterized two tobacco AP1-like promoters (termed NtAP1La and NtAP1Lb1) in transgenic plants using GUS reporter and tissue-speci...

  14. Adrenergic inducibility of AP-1 binding in the rat pineal gland depends on prior photoperiod.

    PubMed

    Guillaumond, F; Becquet, D; Bosler, O; François-Bellan, A M

    2002-10-01

    The main known function of the pineal gland in mammals is the temporal synchronization of physiological rhythms to seasonal changes of day length (photoperiod). In rat, the transcription factor activating protein-1 (AP-1) displays a circadian rhythm in its DNA binding in the pineal gland, which results from the rhythmic expression of Fra-2. We postulated that, if AP-1 is an important component of pineal gland functioning, then variations in photoperiodic conditions should lead to an adaptation of the AP-1 binding rhythm. Here we show that AP-1 binding patterns adapt to variations in lighting conditions, in the same way as the rhythm of arylalkylamine-N-acetyltransferase (AA-NAT) activity. This adaptation appeared to result from photoperiodic adaptation of the rhythmic fra-2 gene expression and was reflected by an adapted delay between the onset of night and the acrophase of the nocturnal peak. We further showed that photoperiodic adaptation of both the AP-1 binding and AA-NAT activity rhythms resulted from adapted changes in adrenergic inducibility of both variables at night onset. We finally provided evidence that AP-1 shared with the CREM gene encoding the transcriptional repressor protein inducible cAMP early repressor (ICER) the ability to be hypersensitive or subsensitive to adrenergic stimuli, depending on prior photoperiod.

  15. TGF-β2 induces Grb2 to recruit PI3-K to TGF-RII that activates JNK/AP-1-signaling and augments invasiveness of Theileria-transformed macrophages

    PubMed Central

    Haidar, Malak; Whitworth, Jessie; Noé, Gaelle; Liu, Wang Qing; Vidal, Michel; Langsley, Gordon

    2015-01-01

    Theileria-infected macrophages display many features of cancer cells such as heightened invasive capacity; however, the tumor-like phenotype is reversible by killing the parasite. Moreover, virulent macrophages can be attenuated by multiple in vitro passages and so provide a powerful model to elucidate mechanisms related to transformed macrophage virulence. Here, we demonstrate that in two independent Theileria-transformed macrophage cell lines Grb2 expression is down-regulated concomitant with loss of tumor virulence. Using peptidimer-c to ablate SH2 and SH3 interactions of Grb2 we identify TGF-receptor II and the p85 subunit of PI3-K, as Grb2 partners in virulent macrophages. Ablation of Grb2 interactions reduces PI3-K recruitment to TGF-RII and decreases PIP3 production, and dampens JNK phosphorylation and AP-1-driven transcriptional activity down to levels characteristic of attenuated macrophages. Loss of TGF-R>PI3-K>JNK>AP-1 signaling negatively impacts on virulence traits such as reduced JAM-L/ITG4A and Fos-B/MMP9 expression that contribute to virulent macrophage adhesion and invasiveness. PMID:26511382

  16. TGF-β2 induces Grb2 to recruit PI3-K to TGF-RII that activates JNK/AP-1-signaling and augments invasiveness of Theileria-transformed macrophages.

    PubMed

    Haidar, Malak; Whitworth, Jessie; Noé, Gaelle; Liu, Wang Qing; Vidal, Michel; Langsley, Gordon

    2015-10-29

    Theileria-infected macrophages display many features of cancer cells such as heightened invasive capacity; however, the tumor-like phenotype is reversible by killing the parasite. Moreover, virulent macrophages can be attenuated by multiple in vitro passages and so provide a powerful model to elucidate mechanisms related to transformed macrophage virulence. Here, we demonstrate that in two independent Theileria-transformed macrophage cell lines Grb2 expression is down-regulated concomitant with loss of tumor virulence. Using peptidimer-c to ablate SH2 and SH3 interactions of Grb2 we identify TGF-receptor II and the p85 subunit of PI3-K, as Grb2 partners in virulent macrophages. Ablation of Grb2 interactions reduces PI3-K recruitment to TGF-RII and decreases PIP3 production, and dampens JNK phosphorylation and AP-1-driven transcriptional activity down to levels characteristic of attenuated macrophages. Loss of TGF-R>PI3-K>JNK>AP-1 signaling negatively impacts on virulence traits such as reduced JAM-L/ITG4A and Fos-B/MMP9 expression that contribute to virulent macrophage adhesion and invasiveness.

  17. Decreased expression of aromatase in the Ishikawa and RL95-2 cells by the isoflavone, puerarin, is associated with inhibition of c-jun expression and AP-1 activity.

    PubMed

    Yu, Chaoqin; Li, Yanwei; Chen, Huan; Yang, Shengsheng; Xie, Guangru

    2008-12-01

    Aromatase P450 (P450(arom)) is overexpressed in endometriosis, endometrial cancers and uterine fibroids. With weak estrogen agonists/antagonists and some other enzymatic activities, isoflavones are increasingly advocated as a natural alternative to estrogen replacement therapy (ERT) and are available as dietary supplements. Puerarin is major isoflavonoid compound isolated from Pueraria lobata, a Chinese medicine known as Gegen. Our clinical study shows that puerarin can be used in the treatment of endometriosis, which improves pain and infertility. Assuming that the effect of puerarin on endometriosis may result from the regulation of aromatase expression or activity, we carried out this study to test the effects of puerarin on aromatase in Ishikawa and RL95-2 cell lines. Our data have demonstrated a significant decrease of P450(arom) expression at both mRNA and protein levels by low dose puerarin treatment in both cell lines. Besides, we found that the -410/-401bp and -565/-559bp regions of aromatase promoter II contained the critical cis-acting elements, binding AP-1 and c-jun. We also found that puerarin exerted a time-course effect on the inhibition of c-jun mRNA, which parallelled that of P450(arom). To further confirm if c-jun is responsible for the P450(arom) regulation by puerarin, we knocked down c-jun expression using siRNA and it indicates that c-jun acts as a considerable transcription factor in regulating P450(arom) expression and activity. Accordingly, the suppression of P450(arom) expression and activity by puerarin treatment may associate with the downregulation of transcription factor AP-1 or c-jun.

  18. Gene expression of immediate early genes of AP-1 transcription factor in human peripheral blood mononuclear cells in response to ionizing radiation.

    PubMed

    Nishad, S; Ghosh, Anu

    2016-11-01

    Ionizing radiation (IR) is considered ubiquitous in nature. The immediate early genes are considered the earliest nuclear targets of IR and are induced in the absence of de novo protein synthesis. Many of these genes encode transcription factors that constitute the first step in signal transduction to couple cytoplasmic effects with long-term cellular response. In this paper, coordinated transcript response of fos and jun family members which constitute activator protein 1 transcription factor was studied in response to IR in human peripheral blood lymphocytes at the G0 stage. Gene expression was monitored 5 min, 1 h and 4 h post-irradiation with Co(60) γ-rays (dose rate of 0.417 Gy/min) and compared with sham-irradiated controls. When gene expression was analyzed at the early time point of 5 min post-irradiation with 0.3 Gy, the studied samples showed two distinct trends. Six out of ten individuals (called 'Group I responders') showed transient, but significant up-regulation for fosB, fosL1, fosL2 and c-jun with an average fold change (FC) ≥1.5 as compared to sham-irradiated controls. The Students's t test p value for all four genes was ≤0.001, indicating strong up-regulation. The remaining four individuals (called Group II responders) showed down-regulation for these same four genes. The average FC with 0.3 Gy in Group II individuals was 0.53 ± 0.22 (p = 0.006) for fosB, 0.60 ± 0.14 (p = 0.001) for fosL1, 0.52 ± 0.16 (p = 0.001) for fosL2 and 0.59 ± 0.28 (p = 0.03) for c-jun. The two groups could be clearly distinguished at this dose/time point using principal component analysis. Both Group I and Group II responders did not show any change in expression for three genes (c-fos, junB and junD) as compared to sham-irradiated controls. Though a similar trend was seen 5 min post-irradiation with a relatively high dose of 1 Gy, the average FC was lower and change in gene expression was not statistically significant (at p < 0

  19. Cooperative binding of AP-1 and TEAD4 modulates the balance between vascular smooth muscle and hemogenic cell fate.

    PubMed

    Obier, Nadine; Cauchy, Pierre; Assi, Salam A; Gilmour, Jane; Lie-A-Ling, Michael; Lichtinger, Monika; Hoogenkamp, Maarten; Noailles, Laura; Cockerill, Peter N; Lacaud, Georges; Kouskoff, Valerie; Bonifer, Constanze

    2016-12-01

    The transmission of extracellular signals into the nucleus involves inducible transcription factors, but how different signalling pathways act in a cell type-specific fashion is poorly understood. Here, we studied the regulatory role of the AP-1 transcription factor family in blood development using embryonic stem cell differentiation coupled with genome-wide transcription factor binding and gene expression analyses. AP-1 factors respond to MAP kinase signalling and comprise dimers of FOS, ATF and JUN proteins. To examine genes regulated by AP-1 and to examine how it interacts with other inducible transcription factors, we abrogated its global DNA-binding activity using a dominant-negative FOS peptide. We show that FOS and JUN bind to and activate a specific set of vascular genes and that AP-1 inhibition shifts the balance between smooth muscle and hematopoietic differentiation towards blood. Furthermore, AP-1 is required for de novo binding of TEAD4, a transcription factor connected to Hippo signalling. Our bottom-up approach demonstrates that AP-1- and TEAD4-associated cis-regulatory elements form hubs for multiple signalling-responsive transcription factors and define the cistrome that regulates vascular and hematopoietic development by extrinsic signals. © 2016. Published by The Company of Biologists Ltd.

  20. Cooperative binding of AP-1 and TEAD4 modulates the balance between vascular smooth muscle and hemogenic cell fate

    PubMed Central

    Obier, Nadine; Cauchy, Pierre; Assi, Salam A.; Gilmour, Jane; Lie-A-Ling, Michael; Lichtinger, Monika; Hoogenkamp, Maarten; Noailles, Laura; Cockerill, Peter N.; Lacaud, Georges; Kouskoff, Valerie

    2016-01-01

    The transmission of extracellular signals into the nucleus involves inducible transcription factors, but how different signalling pathways act in a cell type-specific fashion is poorly understood. Here, we studied the regulatory role of the AP-1 transcription factor family in blood development using embryonic stem cell differentiation coupled with genome-wide transcription factor binding and gene expression analyses. AP-1 factors respond to MAP kinase signalling and comprise dimers of FOS, ATF and JUN proteins. To examine genes regulated by AP-1 and to examine how it interacts with other inducible transcription factors, we abrogated its global DNA-binding activity using a dominant-negative FOS peptide. We show that FOS and JUN bind to and activate a specific set of vascular genes and that AP-1 inhibition shifts the balance between smooth muscle and hematopoietic differentiation towards blood. Furthermore, AP-1 is required for de novo binding of TEAD4, a transcription factor connected to Hippo signalling. Our bottom-up approach demonstrates that AP-1- and TEAD4-associated cis-regulatory elements form hubs for multiple signalling-responsive transcription factors and define the cistrome that regulates vascular and hematopoietic development by extrinsic signals. PMID:27802171

  1. Nitric oxide inhibits apoptosis via AP-1-dependent CD95L transactivation.

    PubMed

    Melino, G; Bernassola, F; Catani, M V; Rossi, A; Corazzari, M; Sabatini, S; Vilbois, F; Green, D R

    2000-05-01

    Several inducers of cytotoxic stress promote apoptotic cell death, which, at least in some cases, involves the CD95/CD95 ligand (CD95L) pathway. The induction of the CD95/CD95L pathway can be activated by the activator protein-1 (AP-1)-mediated up-regulation of the CD95L promoter, which is responsible for the induction of apoptosis elicited by stimuli such as etoposide. We show that nitric oxide (NO) represents a regulatory element able to block apoptosis by interfering with this loop. Etoposide- and C6-ceramide-induced apoptosis in Jurkat T cells with different kinetics. Cell death was accompanied by an increase in DNA-binding activity of the transcription factor AP-1, transactivation of the AP-1 site-containing CD95L promoter, and caspase 3-like protease activation. Using different NO-releasing compounds, we found that apoptosis was prevented in a dose-dependent manner. Furthermore, in both models of apoptosis, NO-releasing compounds dose-dependently reduced: (a) the number of the titratable thiol groups (cysteine residues) of c-Jun; (b) induction of AP-1 DNA-binding activity; (c) AP-1-driven transactivation of the CD95L promoter; and (d) caspase activation. In conclusion, our data demonstrate that NO can modulate cell death at an upstream level, by interfering with the ability of AP-1 to induce CD95L expression.

  2. Cobalt chloride induces delayed cardiac preconditioning in mice through selective activation of HIF-1alpha and AP-1 and iNOS signaling.

    PubMed

    Xi, Lei; Taher, Mohiuddin; Yin, Chang; Salloum, Fadi; Kukreja, Rakesh C

    2004-12-01

    Acute systemic hypoxia induces delayed cardioprotection against ischemia (I)-reperfusion (R) injury via inducible nitric oxide synthase (iNOS)-dependent mechanism. Because CoCl2 is known to elicit hypoxia-like responses, we hypothesized that this chemical would mimic the delayed preconditioning effect in the heart. Adult male mice were pretreated with CoCl2 or saline. The hearts were isolated 24 h later and subjected to 20 min of global I and 30 min of R in Langendorff mode. Myocardial infarct size (% of risk area; mean +/- SE, n=6-8/group) was reduced in mice pretreated with 30 mg/kg CoCl2 (16.1 +/- 3.1% vs. 27.6 +/- 3.3% with saline control; P <0.05) without compromising postischemic cardiac function. Higher doses of CoCl2 failed to induce similar protection. Electrophoretic mobility gel shift assay demonstrated significant enhancement in DNA binding activity of hypoxia-inducible factor 1alpha (HIF-1alpha) and activator protein 1 (AP-1) in nuclear extracts from CoCl2-treated hearts. Activation of HIF-1alpha and AP-1 was evident at 30 min and sustained for the next 4 h after CoCl2 injection. In contrast, CoCl2-induced protection was independent of NF-kappaB activation because no DNA binding or p65 translocation was observed in nuclear extracts. Also, CoCl2-induced cardioprotection was preserved in p50 subunit NF-kappaB-knockout (KO) mice (11.1 +/- 3.0% vs. 25.1 +/- 5.0% in saline-treated p50-KO mice; P <0.05). The infarct-limiting effect of CoCl2 was absent in iNOS-KO mice (20.9 +/- 3.0%). We conclude that in vivo administration of CoCl2 preconditions the heart against I/R injury. The delayed protective effect of CoCl2 is achieved through a distinctive signaling mechanism involving HIF-1alpha, AP-1, and iNOS but independent of NF-kappaB activation.

  3. Low concentrations of copper in drinking water increase AP-1 binding in the brain.

    PubMed

    Lung, Shyang; Li, Huihui; Bondy, Stephen C; Campbell, Arezoo

    2015-12-01

    Copper (Cu) in trace amounts is essential for biological organisms. However, dysregulation of the redox-active metal has been implicated in different neurological disorders such as Wilson's, Menkes', Alzheimer's, and Parkinson's diseases. Since many households use Cu tubing in the plumbing system, and corrosion causes the metal to leach into the drinking water, there may be adverse effects on the central nervous system connected with low-level chronic exposure. The present study demonstrates that treatment with a biologically relevant concentration of Cu for 3 months significantly increases activation of the redox-modulated transcription factor AP-1 in mouse brains. This was independent of an upstream kinase indicated in AP-1 activation. Another redox-active transcription factor, NF-κB, was not significantly modified by the Cu exposure. These results indicate that the effect of Cu on AP-1 is unique and may involve direct modulation of DNA binding.

  4. Kukoamine A Prevents Radiation-Induced Neuroinflammation and Preserves Hippocampal Neurogenesis in Rats by Inhibiting Activation of NF-κB and AP-1.

    PubMed

    Zhang, Yaqiong; Gao, Lingyue; Cheng, Zhihua; Cai, Jiayi; Niu, Yixuan; Meng, Weihong; Zhao, Qingchun

    2017-02-01

    Impaired hippocampal neurogenesis and neuroinflammation are involved in the pathogenesis of radiation-induced brain injury. Kukoamine A (KuA) was demonstrated to have neuroprotective effects through inhibiting oxidative stress and apoptosis after whole-brain irradiation (WBI) in rats. The aim of this study was to investigate whether administration of KuA would prevent radiation-induced neuroinflammation and the detrimental effect on hippocampal neurogenesis. For this study, male Wistar rats received either sham irradiation or WBI (30 Gy single dose of X-rays) followed by the immediate injection of either KuA or vehicle intravenously. The dose of KuA was 5, 10, and 20 mg/kg, respectively. The levels of pro-inflammatory cytokines were assayed by ELISA kits. The newborn neurons were detected by 5-bromo-2-deoxyuridine (BrdU)/neuronal nuclei (NeuN) double immunofluorescence. Microglial activation was measured by Iba-1 immunofluorescence. The expression of Cox-2 and the activation of nuclear factor κB (NF-κB), activating protein 1(AP-1), and PPARδ were evaluated by western blot. WBI led to a significant increase in the level of TNF-α, IL-1β, and Cox-2, and it was alleviated by KuA administration. KuA attenuated microglial activation in rat hippocampus after WBI. Neurogenesis impairment induced by WBI was ameliorated by KuA. Additionally, KuA alleviated the increased translocation of NF-κB p65 subunit and phosphorylation of c-jun induced by WBI and elevated the expression of PPARδ. These data indicate that KuA could ameliorate the neuroinflammatory response and protect neurogenesis after WBI, partially through regulating the activation of NF-κB, AP-1, and PPARδ.

  5. Dimerumic acid inhibits SW620 cell invasion by attenuating H₂O₂-mediated MMP-7 expression via JNK/C-Jun and ERK/C-Fos activation in an AP-1-dependent manner.

    PubMed

    Ho, Bing-Ying; Wu, Yao-Ming; Chang, King-Jen; Pan, Tzu-Ming

    2011-01-01

    Reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂) in the tumor microenvironment play important roles in tumor invasion and metastasis. Recently, ROS have been reported to cause a significant increase in the production and expression of matrix metalloproteinase (MMP)-7, which is closely correlated with metastatic colorectal cancer. The present study was undertaken to evaluate the scavenging activity of dimerumic acid (DMA) for H₂O₂ isolated from Monascus-fermented rice to investigate the inhibitory effects of DMA on the invasive potential of SW620 human colon cancer cells, and to explore the mechanisms underlying both these phenomena. Our results showed that increased MMP-7 expression due to H₂O₂ exposure was mediated by activation of mitogen-activated protein kinases (MAPKs) such as Jun N-terminal kinase (JNK), extracellular-regulated kinase (ERK), and p38 kinase. DMA pretreatment suppressed activation of H₂O₂-mediated MAPK pathways and cell invasion. Moreover, H₂O₂-triggered MMP-7 production was demonstrated via JNK/c-Jun and ERK/c-Fos activation in an activating protein 1 (AP-1)-dependent manner. Taken together, these results suggest that DMA suppresses H₂O₂-induced cell invasion by inhibiting AP-1-mediated MMP-7 gene transcription via the JNK/c-Jun and ERK/c-Fos signaling pathways in SW620 human colon cancer cells. Our data suggest that DMA may be useful in minimizing the development of colorectal metastasis. In the future, DMA supplementation may be a beneficial antioxidant to enhance surgical outcomes.

  6. Contribution of AP-1 interference induced by TAC-101 to tumor growth suppression in a hepatocellular carcinoma model.

    PubMed

    Eshima, Kokoro; Fukaya, Satoshi; Sugimoto, Akiko; Mori, Tomoko; Yokoi, Hiromi; Yamamoto, Yasuji; Sugiura, Shin; Honda, Shizu; Masuko, Norio; Murakami, Koji; Yamasaki, Yasundo; Kagechika, Hiroyuki

    2009-01-01

    TAC-101, 4-[3,5-bis(trimethylsilyl)benzamido] benzoic acid, is a synthetic ligand for retinoic acid receptor (RAR)-alpha. Here, we demonstrate the contribution of TAC-101-induced AP-1 interference to stabilization of tumor growth. TAC-101 induced transcriptional activation of RAR, resulting in marked elevation of RARbeta, a representative retinoid response marker, and it also significantly repressed the transcriptional activity of AP-1 in JHH-7 cells. In contrast to JHH-7, JHH-6 is another RARalpha-expressing human hepatocellular carcinoma (HCC) cell line with constitutive activation of AP-1, but it is retinoid insensitive and did not respond to the TAC-101-induced RAR signal. TAC-101 did not inhibit AP-1 activity of the JHH-6 cell line, showing that AP-1 interference by TAC-101 must be in parallel with RAR activation. Interleukin-8 (IL-8), one of the AP-1-regulated factors which correlate with a poor prognosis in HCC patients, was found to be overexpressed in JHH-7 cells. TAC-101 reduced IL-8 production without cytotoxicity and inhibited the progression of HCC in the orthotopic mouse model with decreased tumor IL-8 level. These results suggest that downregulation of the extracellular biomarker for AP-1 interference via the induction of retinoid signals will enhance the pharmacological effect of TAC-101 on HCC and it could be useful as a surrogate biomarker of therapeutic efficacy.

  7. Cigarette smoke activates human monocytes by an oxidant-AP-1 signaling pathway: implications for steroid resistance.

    PubMed

    Walters, Matthew J; Paul-Clark, Mark J; McMaster, Shaun K; Ito, Kazuhiro; Adcock, Ian M; Mitchell, Jane A

    2005-11-01

    Smoking cigarettes is a major risk factor for the development of cardiovascular and respiratory disease. Moreover, smoking-induced pathophysiology is often resistant to the anti-inflammatory effects of glucocorticoids. The nature of cigarette smoke-induced inflammation is still not defined, although neutrophil recruitment and activation seem to be consistent features. In the current study, we have used a range of approaches to demonstrate that cigarette smoke activates human monocytes and macrophages to release the CXC chemokine CXCL8 [(interleukin-8 (IL-8)]. Furthermore, we show for the first time that cigarette smoke synergizes with proinflammatory cytokines IL-1beta and tumor necrosis factor-alpha, and it is this interaction that confers steroid resistance to smoke-induced CXCL8 release. We go on to show that smoke-induced activation of human cells is an oxidant-mediated phenomenon acting through activator protein-1, but not nuclear factor kappaB, pathway. These observations add significantly to our understanding of smoke as an inflammatory stimulus that has implications for potential the development of treatments of smoking or related disease.

  8. Retinoids interfere with the AP1 signalling pathway in human breast cancer cells.

    PubMed

    Dedieu, Stephane; Lefebvre, Philippe

    2006-06-01

    Retinoic acid and its synthetic analogs exert major effects on many biological processes including cell proliferation and differentiation and are now considered as promising pharmacological agents for prevention and treatment of various cancers. The capacity of retinoids to inhibit AP1-responsive genes seems to be the basis for the chemopreventive and chemotherapeutic effects of these agents against hyperproliferative diseases. However, the molecular basis of retinoid antiproliferative properties remains to this day largely unknown. Here, we showed that retinoids inhibit phorbol ester-induced MMP-1 and MMP-3 expression in human breast cancer cells. Transcriptional interference was observed for both retinoid agonist and antagonist treatments, revealing separated transactivation and transrepression functions of retinoids. In addition, we examined MAP kinases as potential targets of retinoid signalling in human breast cancer cells and demonstrated that retinoids repress AP1-responsive gene expression by inhibiting MKK6/p38 and mainly MEK/ERK signalling pathways. On the contrary, the JNK-dependent pathway was not identified as a molecular relay for AP1 activity and was insensitive to retinoid treatments. Finally, we established that overexpressed c-fos and c-jun partially abolished the ability of retinoids to inhibit AP1 activity, suggesting that c-jun and/or c-fos containing dimers may constitute one target of retinoids for transrepression of AP1. All together, our data help to improve our understanding of how retinoids antagonize AP1 activity and may regulate tumoral cell proliferation.

  9. HIV-1 Nef Induces CCL5 production in astrocytes through p38-MAPK and PI3K/Akt pathway and utilizes NF-kB, CEBP and AP-1 transcription factors

    NASA Astrophysics Data System (ADS)

    Liu, Xun; Shah, Ankit; Gangwani, Mohitkumar R.; Silverstein, Peter S.; Fu, Mingui; Kumar, Anil

    2014-03-01

    The prevalence of HIV-associated neurocognitive disorders (HAND) remains high in patients infected with HIV-1. The production of pro-inflammatory cytokines by astrocytes/microglia exposed to viral proteins is thought to be one of the mechanisms leading to HIV-1- mediated neurotoxicity. In the present study we examined the effects of Nef on CCL5 induction in astrocytes. The results demonstrate that CCL5 is significantly induced in Nef-transfected SVGA astrocytes. To determine the mechanisms responsible for the increased CCL5 caused by Nef, we employed siRNA and chemical antagonists. Antagonists of NF-κB, PI3K, and p38 significantly reduced the expression levels of CCL5 induced by Nef transfection. Furthermore, specific siRNAs demonstrated that the Akt, p38MAPK, NF-κB, CEBP, and AP-1 pathways play a role in Nef-mediated CCL5 expression. The results demonstrated that the PI3K/Akt and p38 MAPK pathways, along with the transcription factors NF-κB, CEBP, and AP-1, are involved in Nef-induced CCL5 production in astrocytes.

  10. Bamboo extract reduces interleukin 6 (IL-6) overproduction under lipotoxic conditions through inhibiting the activation of NF-κB and AP-1 pathways.

    PubMed

    Higa, Jason K; Panee, Jun

    2011-07-01

    Interleukin 6 (IL-6) is an inflammatory cytokine overexpressed in obese individuals that contributes to the development of diseases such as insulin resistance, type 2 diabetes, and cardiovascular disease. This study investigated the inhibitory effect of an extract from the bamboo Phyllostachys edulis (BEX) on lipotoxicity-induced over-production of IL-6 in metabolic cell lines. Palmitic acid (PA, 0.4mM) was used to induce lipotoxicity in murine C2C12, 3T3-L1, and Hepa6 cells. Both intra- and extra-cellular protein concentrations of IL-6 were measured in the three cell lines after PA treatment with or without the presence of BEX using cytometric bead assays. IL-6 mRNA levels were quantified using real-time PCR, and nuclear concentrations of c-fos, p50 and p65 proteins were measured using DNA-binding ELISA in 3T3-L1 cells. Lipotoxicity increased IL-6 protein concentration in both cytosol and media collected from myoblast and myotube C2C12, as well as preadipose and adipose 3T3-L1, and the presence of BEX (0.5%, v/v) effectively inhibited this overproduction. IL-6 protein expression in hepatic Hepa6 cells was less affected by lipotoxicity. BEX significantly ameliorated PA-induced upregulation of IL-6 mRNA, which correlated with a reduction in nuclear translocation of p50, p65, and c-fos proteins with the presence of BEX, indicating inhibition of NF-κB and AP-1 activation. In summary, BEX inhibits lipotoxicity-induced IL-6 overproduction in muscle and adipose cell lines through the NF-κB and AP-1 pathways, implicating a potential application of this natural product as a cost-effective anti-inflammation nutraceutical.

  11. A mechanism of AP-1 suppression through interaction of c-Fos with lamin A/C

    PubMed Central

    Ivorra, Carmen; Kubicek, Markus; González, José M.; Sanz-González, Silvia M.; Álvarez-Barrientos, Alberto; O'Connor, José-Enrique; Burke, Brian; Andrés, Vicente

    2006-01-01

    AP-1 (Activating Protein 1) transcription factor activity is tightly regulated at multiple levels, including dimer formation (i.e., Fos/Jun). Here we show that the intermediate filament protein lamin A/C suppresses AP-1 function through direct interaction with c-Fos, and that both proteins can interact and colocalize at the nuclear envelope (NE) in mammalian cells. Perinuclear localization of c-Fos is absent in Lmna-null cells but can be restored by lamin A overexpression. In vitro, preincubation of c-Fos with lamin A prior to the addition of c-Jun inhibits AP-1 DNA-binding activity. In vivo, overexpression of lamin A reduces the formation of c-Fos/c-Jun heterodimers, and suppresses AP-1 DNA-binding and transcriptional activity. Notably, c-Fos colocalizes with lamin A/C at the NE in starvation-synchronized quiescent cells lacking detectable AP-1 DNA binding. In contrast, serum-induced AP-1 DNA-binding activity coincides with abundant nucleoplasmic c-Fos expression without changes in lamin A/C localization. We also found that Lmna-null cells display enhanced proliferation. In contrast, lamin A overexpression causes growth arrest, and ectopic c-Fos partially overcomes lamin A/C-induced cell cycle alterations. We propose lamin A/C-mediated c-Fos sequestration at the NE as a novel mechanism of transcriptional and cell cycle control. PMID:16452503

  12. One-step affinity tag purification of full-length recombinant human AP-1 complexes from bacterial inclusion bodies using a polycistronic expression system

    PubMed Central

    Wang, Wei-Ming; Lee, A-Young; Chiang, Cheng-Ming

    2008-01-01

    The AP-1 transcription factor is a dimeric protein complex formed primarily between Jun (c-Jun, JunB, JunD) and Fos (c-Fos, FosB, Fra-1, Fra-2) family members. These distinct AP-1 complexes are expressed in many cell types and modulate target gene expression implicated in cell proliferation, differentiation, and stress responses. Although the importance of AP-1 has long been recognized, the biochemical characterization of AP-1 remains limited in part due to the difficulty in purifying full-length, reconstituted dimers with active DNA-binding and transcriptional activity. Using a combination of bacterial coexpression and epitope-tagging methods, we successfully purified all 12 heterodimers (3 Jun × 4 Fos) of full-length human AP-1 complexes as well as c-Jun/c-Jun, JunD/JunD, and c-Jun/JunD dimers from bacterial inclusion bodies using one-step nickel-NTA affinity tag purification following denaturation and renaturation of coexpressed AP-1 subunits. Coexpression of two constitutive components in a dimeric AP-1 complex helps stabilize the proteins when compared with individual protein expression in bacteria. Purified dimeric AP-1 complexes are functional in sequence-specific DNA binding, as illustrated by electrophoretic mobility shift assays and DNase I footprinting, and are also active in transcription with in vitro-reconstituted human papillomavirus (HPV) chromatin containing AP-1-binding sites in the native configuration of HPV nucleosomes. The availability of these recombinant full-length human AP-1 complexes has greatly facilitated mechanistic studies of AP-1-regulated gene transcription in many biological systems. PMID:18329890

  13. One-step affinity tag purification of full-length recombinant human AP-1 complexes from bacterial inclusion bodies using a polycistronic expression system.

    PubMed

    Wang, Wei-Ming; Lee, A-Young; Chiang, Cheng-Ming

    2008-05-01

    The AP-1 transcription factor is a dimeric protein complex formed primarily between Jun (c-Jun, JunB, JunD) and Fos (c-Fos, FosB, Fra-1, Fra-2) family members. These distinct AP-1 complexes are expressed in many cell types and modulate target gene expression implicated in cell proliferation, differentiation, and stress responses. Although the importance of AP-1 has long been recognized, the biochemical characterization of AP-1 remains limited in part due to the difficulty in purifying full-length, reconstituted dimers with active DNA-binding and transcriptional activity. Using a combination of bacterial coexpression and epitope-tagging methods, we successfully purified all 12 heterodimers (3 Junx4 Fos) of full-length human AP-1 complexes as well as c-Jun/c-Jun, JunD/JunD, and c-Jun/JunD dimers from bacterial inclusion bodies using one-step nickel-NTA affinity tag purification following denaturation and renaturation of coexpressed AP-1 subunits. Coexpression of two constitutive components in a dimeric AP-1 complex helps stabilize the proteins when compared with individual protein expression in bacteria. Purified dimeric AP-1 complexes are functional in sequence-specific DNA binding, as illustrated by electrophoretic mobility shift assays and DNase I footprinting, and are also active in transcription with in vitro-reconstituted human papillomavirus (HPV) chromatin containing AP-1-binding sites in the native configuration of HPV nucleosomes. The availability of these recombinant full-length human AP-1 complexes has greatly facilitated mechanistic studies of AP-1-regulated gene transcription in many biological systems.

  14. AP-1(c-Jun/FosB) mediates xFoxD5b expression in Xenopus early developmental neurogenesis.

    PubMed

    Yoon, Jaeho; Kim, Jung-Ho; Lee, Ok-Joo; Lee, Sung-Young; Lee, Seung-Hwan; Park, Jae-Bong; Lee, Jae-Yong; Kim, Sung-Chan; Kim, Jaebong

    2013-01-01

    AP-1 (activator protein-1) is composed of Jun and Fos proteins and functions in cell proliferation, apoptosis and differentiation. Previous studies have demonstrated that different AP-1 complexes participate in the determination of various cell fates. However, the role of different AP-1 complexes during early vertebrate development is not yet fully understood. In the present study, we demonstrate that AP-1(c-Jun/FosB) regulates neurogenesis via FoxD5b expression. We show that FoxD5 was induced by the inhibition of BMP and that FoxD5b plays roles in neurogenesis. Additionally, we show that the FoxD5b promoter region within -1336 and -1316 contains an AP-1 binding site, which is required for the transcriptional regulation of FoxD5b and is induced by the inhibition of BMP signaling in animal cap explants. Moreover, c-Jun, a component of AP-1, directly binds to the AP-1 binding site of the FoxD5b promoter and induces FoxD5b expression cooperatively with FosB, but not with c-Fos or Fra-1. Altogether, these results suggest that AP-1(c-Jun/FosB) may play a role in neurogenesis via the induction of FoxD5b expression during early vertebrate development.

  15. Transcriptomic analysis by RNA-seq reveals AP-1 pathway as key regulator that green tea may rely on to inhibit lung tumorigenesis.

    PubMed

    Pan, Jing; Zhang, Qi; Xiong, Donghai; Vedell, Peter; Yan, Ying; Jiang, Hui; Cui, Peng; Ding, Feng; Tichelaar, Jay W; Wang, Yian; Lubet, Ronald A; You, Ming

    2014-01-01

    Green tea is a promising chemopreventive agent for lung cancer. Multiple signaling events have been reported, however, the relative importance of these mechanisms in mediating the chemopreventive function of green tea is unclear. In the present study, to examine the involvement of AP-1 in green tea polyphenols induced tumor inhibition, human NSCLC cell line H1299 and mouse SPON 10 cells were identified as AP-1 dependent, as these two lines exhibit high constitutive AP-1 activity, and when TAM67 expression was induced with doxycycline, cell growth was inhibited and correlated with suppressed AP-1 activity. RNA-seq was used to determine the global transcriptional effects of AP-1 inhibition and also uncover the possible involvement of AP-1 in tea polyphenols induced chemoprevention. TAM67 mediated changes in gene expression were identified, and within down-regulated genes, AP-1 was identified as a key transcription regulator. RNA-seq analysis revealed that Polyphenon E-treated cells shared 293 commonly down-regulated genes within TAM67 expressing H1299 cells, and by analysis of limited Chip-seq data, over 10% of the down-regulated genes contain a direct AP-1 binding site, indicating that Polyphenon E elicits chemopreventive activity by regulating AP-1 target genes. Conditional TAM67 expressing transgenic mice and NSCLC cell lines were used to further confirm that the chemopreventive activity of green tea is AP-1 dependent. Polyphenon E lost its chempreventive function both in vitro and in vivo when AP-1 was inhibited, indicating that AP-1 inhibition is a major pathway through which green tea exhibits chemopreventive effects.

  16. ATP6AP1 — EDRN Public Portal

    Cancer.gov

    ATP6AP1 is an integral membrane protein composed of at least 10 subunits. It is responsible for acidifying various eukaryotic intracellular organelles. ATP6AP1, also known as vacuolar ATPase or V-ATPase, has a cytosolic V1 domain and a transmembrane V0 domain. The acidification performed by ATP6AP1 is necessary for intracellular processes such as protein sorting, zymogen activation, and receptor-mediated endocytosis.

  17. A dual AP-1 and SMAD decoy ODN suppresses tissue fibrosis and scarring in mice.

    PubMed

    Yuan, Hong-Feng; Huang, Hong; Li, Xiang-Yun; Guo, Wei; Xing, Wei; Sun, Zhi-Ya; Liang, Hua-Ping; Yu, Jian; Chen, Dong-Feng; Wang, Zheng-Guo; Hao, Jin; Xu, Xiang

    2013-04-01

    The transforming growth factor-β (TGF-β) signaling pathway promotes tissue fibrosis and scarring through SMAD (small mothers against decapentaplegic)-dependent and SMAD-independent mechanisms. However, inhibition of SMAD-mediated signal transduction alone induces an excessive inflammatory response that impairs the antifibrotic effects of TGF-β inhibitors. In this study, we designed and characterized a dual-functional transcription activator protein 1 (AP-1) and SMAD decoy oligodeoxynucleotide, antifibrosis oligodeoxynucleotide 4 (AFODN4) in vitro and in vivo. AFODN4 binds directly to recombinant AP-1 and SMAD with high affinity. AFODN4 significantly inhibited the DNA-binding and transcriptional activities of both AP-1 and SMAD, as well as the production of fibrotic mediators stimulated by TGF-β1 or TGF-β2 in L929 murine fibroblasts. Local administration of AFODN4 significantly inhibited fibrosis associated with acute dermal wounds in mice. Intriguingly, AFODN4 inhibited AP-1-mediated production of proinflammatory mediators, which can be caused by blockage of SMAD alone in vitro and in vivo. Collectively, these findings suggest that dual inhibition of SMAD and AP-1 signaling by AFODN4 is a useful strategy for the development of new antifibrotic agents.

  18. Citrus bergamia Juice Extract Attenuates β-Amyloid-Induced Pro-Inflammatory Activation of THP-1 Cells Through MAPK and AP-1 Pathways.

    PubMed

    Currò, Monica; Risitano, Roberto; Ferlazzo, Nadia; Cirmi, Santa; Gangemi, Chiara; Caccamo, Daniela; Ientile, Riccardo; Navarra, Michele

    2016-02-08

    Flavonoids have been shown to be effective in protecting against age-related cognitive and motor decline in both in vitro and in vivo models. Recently, a flavonoid-rich extract of Citrus bergamia juice (BJe) has been shown to display anti-oxidant and anti-inflammatory properties against LPS-induced activation of human THP-1 monocytes. In the light of these observations, we wondered whether BJe may be beneficial against neuroinflammatory processes, such as those observed in Alzheimer's disease. To this aim we used THP-1 monocytes to investigate the mechanisms underlying the beneficial potential of BJe against amyloid-beta1-42 (Aβ1-42) -mediated inflammation. Exposure of THP-1 cells to Aβ1-42 significantly induced the expression and secretion of IL-6 and IL-1β in THP-1 cells and increased the phosphorylation of ERK 1/2 as well as p46 and p54 members of JNK family. Moreover, Aβ1-42 raises AP-1 DNA binding activity in THP-1-treated cells. Interestingly, all these effects were reduced in the presence of BJe. Our data indicate that BJe may effectively counteract the pro-inflammatory activation of monocytes/microglial cells exposed to amyloid fibrils, suggesting a promising role as a natural drug against neuroinflammatory processes.

  19. BRAFV600E induces ABCB1/P-glycoprotein expression and drug resistance in B-cells via AP-1 activation

    PubMed Central

    Tsai, Yo-Ting; Lozanski, Gerard; Lehman, Amy; Sass, Ellen J.; Hertlein, Erin; Salunke, Santosh B.; Chen, Ching-Shih; Grever, Michael R.; Byrd, John C.; Lucas, David M.

    2015-01-01

    A subset of patients with chronic lymphocytic leukemia (CLL) and nearly all patients with classic hairy cell leukemia (HCL) harbor somatic BRAF activating mutations. However, the pathological role of activated BRAF in B-cell leukemia development and progression remains unclear. In addition, although HCL patients respond well to the BRAFV600E inhibitor vemurafenib, relapses are being observed, suggesting the development of drug resistance in patients with this mutation. To investigate the biological role of BRAFV600E in B-cell leukemia, we generated a CLL-like B-cell line, OSUCLL, with doxycycline-inducible BRAFV600E expression. Microarray and real-time PCR analysis showed that ABCB1 mRNA is upregulated in these cells, and P-glycoprotein (P-gp) expression as well as function were confirmed by immunoblot and rhodamine exclusion assays. Additionally, pharmacological inhibition of BRAFV600E and MEK alleviated the BRAFV600E-induced ABCB1/P-gp expression. ABCB1 reporter assays and gel shift assays demonstrated that AP-1 activity is crucial in this mechanism. This study therefore uncovers a pathological role for BRAFV600E in B-cell leukemia, and provides further evidence that combination strategies with inhibitors of BRAFV600E and MEK can be used to delay disease progression and occurrence of resistance. PMID:26350141

  20. BRAF(V600E) induces ABCB1/P-glycoprotein expression and drug resistance in B-cells via AP-1 activation.

    PubMed

    Tsai, Yo-Ting; Lozanski, Gerard; Lehman, Amy; Sass, Ellen J; Hertlein, Erin; Salunke, Santosh B; Chen, Ching-Shih; Grever, Michael R; Byrd, John C; Lucas, David M

    2015-09-05

    A subset of patients with chronic lymphocytic leukemia (CLL) and nearly all patients with classic hairy cell leukemia (HCL) harbor somatic BRAF activating mutations. However, the pathological role of activated BRAF in B-cell leukemia development and progression remains unclear. In addition, although HCL patients respond well to the BRAF(V600E) inhibitor vemurafenib, relapses are being observed, suggesting the development of drug resistance in patients with this mutation. To investigate the biological role of BRAF(V600E) in B-cell leukemia, we generated a CLL-like B-cell line, OSUCLL, with doxycycline-inducible BRAF(V600E) expression. Microarray and real-time PCR analysis showed that ABCB1 mRNA is upregulated in these cells, and P-glycoprotein (P-gp) expression as well as function were confirmed by immunoblot and rhodamine exclusion assays. Additionally, pharmacological inhibition of BRAF(V600E) and MEK alleviated the BRAF(V600E)-induced ABCB1/P-gp expression. ABCB1 reporter assays and gel shift assays demonstrated that AP-1 activity is crucial in this mechanism. This study, uncovers a pathological role for BRAF(V600E) in B-cell leukemia, and provides further evidence that combination strategies with inhibitors of BRAF(V600E) and MEK can be used to delay disease progression and occurrence of resistance.

  1. Citrus bergamia Juice Extract Attenuates β-Amyloid-Induced Pro-Inflammatory Activation of THP-1 Cells Through MAPK and AP-1 Pathways

    PubMed Central

    Currò, Monica; Risitano, Roberto; Ferlazzo, Nadia; Cirmi, Santa; Gangemi, Chiara; Caccamo, Daniela; Ientile, Riccardo; Navarra, Michele

    2016-01-01

    Flavonoids have been shown to be effective in protecting against age-related cognitive and motor decline in both in vitro and in vivo models. Recently, a flavonoid-rich extract of Citrus bergamia juice (BJe) has been shown to display anti-oxidant and anti-inflammatory properties against LPS-induced activation of human THP-1 monocytes. In the light of these observations, we wondered whether BJe may be beneficial against neuroinflammatory processes, such as those observed in Alzheimer’s disease. To this aim we used THP-1 monocytes to investigate the mechanisms underlying the beneficial potential of BJe against amyloid-beta1–42 (Aβ1−42) -mediated inflammation. Exposure of THP-1 cells to Aβ1−42 significantly induced the expression and secretion of IL-6 and IL-1β in THP-1 cells and increased the phosphorylation of ERK 1/2 as well as p46 and p54 members of JNK family. Moreover, Aβ1−42 raises AP-1 DNA binding activity in THP-1-treated cells. Interestingly, all these effects were reduced in the presence of BJe. Our data indicate that BJe may effectively counteract the pro-inflammatory activation of monocytes/microglial cells exposed to amyloid fibrils, suggesting a promising role as a natural drug against neuroinflammatory processes. PMID:26853104

  2. Inhibition of transcriptional activity of c-JUN by SIRT1

    SciTech Connect

    Gao Zhanguo; Ye Jianping

    2008-11-28

    c-JUN is a major component of heterodimer transcription factor AP-1 (Activator Protein-1) that activates gene transcription in cell proliferation, inflammation and stress responses. SIRT1 (Sirtuin 1) is a histone deacetylase that controls gene transcription through modification of chromatin structure. However, it is not clear if SIRT1 regulates c-JUN activity in the control of gene transcription. Here, we show that SIRT1 associated with c-JUN in co-immunoprecipitation of whole cell lysate, and inhibited the transcriptional activity of c-JUN in the mammalian two hybridization system. SIRT1 was found in the AP-1 response element in the matrix metalloproteinase-9 (MMP9) promoter DNA leading to inhibition of histone 3 acetylation as shown in a ChIP assay. The SIRT1 signal was reduced by the AP-1 activator PMA, and induced by the SIRT1 activator Resveratrol in the promoter DNA. SIRT1-mediaetd inhibition of AP-1 was demonstrated in the MMP9 gene expression at the gene promoter, mRNA and protein levels. In mouse embryonic fibroblast (MEF) with SIRT1 deficiency (SIRT1{sup -/-}), mRNA and protein of MMP9 were increased in the basal condition, and the inhibitory activity of Resveratrol was significantly attenuated. Glucose-induced MMP9 expression was also inhibited by SIRT1 in response to Resveratrol. These data consistently suggest that SIRT1 directly inhibits the transcriptional activity of AP-1 by targeting c-JUN.

  3. Effect Of Simulated Microgravity On Activated T Cell Gene Transcription

    NASA Technical Reports Server (NTRS)

    Morrow, Maureen A.

    2003-01-01

    Studies of T lymphocytes under the shear stress environment of clinorotation have demonstrated an inhibition of activation in response to TCR mediated signaling. These results mimic those observed during space flight. This work investigates the molecular signaling events of T lymphocyte activation with clinorotation. Purified human T lymphocytes and the T cell clone Jurkat exhibit an uncoupling of signaling as mediated through the TCR. Activation of the transcription factor AP-1 is inhibited while activation of NFAT occurs. NFAT dephosphorylation and activation is dependent on sustained Ca(++) influx. Alternatively, AP-1, which consists of two transcription factors, jun and fos, is activated by PKC and Ras mediated pathways. TCR signaling is known to be dependent on cytoskeletal rearrangements, in particular, raft aggregation is critical. Raft aggregation, as mediated through GM, crosslinking, overcomes the inhibition of T lymphocyte activation with clinorotation, indicating that the block is occurring upstream of raft aggregation. Clinorotation is shown to have an effect similar to a weak TCR signal.

  4. Effect Of Simulated Microgravity On Activated T Cell Gene Transcription

    NASA Technical Reports Server (NTRS)

    Morrow, Maureen A.

    2003-01-01

    Studies of T lymphocytes under the shear stress environment of clinorotation have demonstrated an inhibition of activation in response to TCR mediated signaling. These results mimic those observed during space flight. This work investigates the molecular signaling events of T lymphocyte activation with clinorotation. Purified human T lymphocytes and the T cell clone Jurkat exhibit an uncoupling of signaling as mediated through the TCR. Activation of the transcription factor AP-1 is inhibited while activation of NFAT occurs. NFAT dephosphorylation and activation is dependent on sustained Ca(++) influx. Alternatively, AP-1, which consists of two transcription factors, jun and fos, is activated by PKC and Ras mediated pathways. TCR signaling is known to be dependent on cytoskeletal rearrangements, in particular, raft aggregation is critical. Raft aggregation, as mediated through GM, crosslinking, overcomes the inhibition of T lymphocyte activation with clinorotation, indicating that the block is occurring upstream of raft aggregation. Clinorotation is shown to have an effect similar to a weak TCR signal.

  5. Drosophila Jun kinase regulates expression of decapentaplegic via the ETS-domain protein Aop and the AP-1 transcription factor DJun during dorsal closure.

    PubMed

    Riesgo-Escovar, J R; Hafen, E

    1997-07-01

    During Drosophila embryogenesis, ectodermal cells of the lateral epithelium stretch in a coordinated fashion to internalize the amnioserosa cells and close the embryo dorsally. This process, dorsal closure, requires two signaling pathways: the Drosophila Jun-amino-terminal kinase (DJNK) pathway and the Dpp pathway. We have identified mutations in DJun and show that DJNK controls dorsal closure by activating DJun and inactivating the ETS repressor Aop/Yan by phosphorylation. DJun and Aop regulate dpp expression in the most dorsal row of cells. Secreted Dpp then instructs more ventrally located cells to stretch. Our results provide a causal link between the DJNK and Dpp pathways during dorsal closure. Interestingly, in vertebrates, transforming growth factor-beta and c-Jun regulate collagenase gene expression during wound healing, a process that also involves the closing of an epithelial sheath.

  6. Differential expression of AP-1 proteins in human myometrium after spontaneous term labour onset.

    PubMed

    Lim, Ratana; Lappas, Martha

    2014-06-01

    The aims of this study were (i) to determine the localisation of activator protein (AP)-1 family members (cFos, FosB, cJun, JunB and JunD) in human myometrium; and (ii) to determine the effect of human term labour on the expression of AP-1 family of transcription factors in myometrium. This localised the AP-1 family members cFos, FosB, cJun, JunB and JunD in human myometrium was performed by immunohistochemistry. The effect of term labour on the expression of these family members at the mRNA and protein level was assessed by qRT-PCR and Western blotting, respectively. The effect of pro-inflammatory stimuli on AP-1 transcriptional activity was assessed using a luciferase assay in primary human myometrial cells. Immunohistochemical expression of cFos, FosB, cJun, JunB and JunD were all present in human myometrial tissue and displayed cytoplasmic staining. FosB and JunD also displayed nuclear staining. Term labour was associated with an increase in cFos and JunB mRNA and protein expression. On the other hand, JunD mRNA and protein expression was decreased with labour. FosB mRNA was increased with labour, but there was no change at the protein level. There was no change in cJun mRNA or protein expression. AP-1 transcriptional activity was increased in human myometrial cells by the pro-inflammatory cytokine TNF-α. There was, however, no effect of the bacterial products lipopolysaccharide (LPS; TLR4 ligand), iE-DAP (NOD1 ligand), MDP (NOD2 ligand), FSL-1 (TLR2 ligand) or flagellin (TLR5 ligand) on AP-1 transcriptional activity. This study shows that human labour is associated with changes in AP-1 family members. Further studies are required to determine the exact role of the AP-1 family members in myometrium. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  7. Retinoic acid is a negative regulator of AP-1-responsive genes.

    PubMed Central

    Schüle, R; Rangarajan, P; Yang, N; Kliewer, S; Ransone, L J; Bolado, J; Verma, I M; Evans, R M

    1991-01-01

    We present evidence that retinoic acid can down-regulate transcriptional activation by the nuclear protooncogene c-jun. All three members of the retinoic acid receptor (RAR) subfamily (RAR alpha, RAR beta, and RAR gamma) can repress transcriptional induction of the human collagenase gene or a heterologous promoter that contains the collagenase promoter AP-1-binding site. In contrast, the retinoid X receptor fails to repress Jun/AP-1 activity, demonstrating a significant difference between the two regulatory systems through which retinoids exert their transcriptional control. Analysis of RAR alpha mutants in transfection studies reveals that the DNA-binding domain is important for the inhibition of Jun/AP-1 activity, even though the RAR does not bind the collagenase AP-1 site. Rather, gel-retardation assays reveal that bacterially expressed full-length RAR alpha inhibits binding of Jun protein to target DNA. These data suggest that the RAR alpha may form a nonproductive complex with c-Jun and provides a simple mechanisms by which retinoic acid may limit cell growth and possibly malignant progression. Images PMID:1648728

  8. Genome-scale functional profiling of the mammalian AP-1 signaling pathway

    PubMed Central

    Chanda, Sumit K.; White, Suhaila; Orth, Anthony P.; Reisdorph, Richard; Miraglia, Loren; Thomas, Russell S.; DeJesus, Paul; Mason, Daniel E.; Huang, Qihong; Vega, Raquel; Yu, De-Hua; Nelson, Christian G.; Smith, Brendan M.; Terry, Robert; Linford, Alicia S.; Yu, Yang; Chirn, Gung-wei; Song, Chuanzheng; Labow, Mark A.; Cohen, Dalia; King, Frederick J.; Peters, Eric C.; Schultz, Peter G.; Vogt, Peter K.; Hogenesch, John B.; Caldwell, Jeremy S.

    2003-01-01

    Large-scale functional genomics approaches are fundamental to the characterization of mammalian transcriptomes annotated by genome sequencing projects. Although current high-throughput strategies systematically survey either transcriptional or biochemical networks, analogous genome-scale investigations that analyze gene function in mammalian cells have yet to be fully realized. Through transient overexpression analysis, we describe the parallel interrogation of ≈20,000 sequence annotated genes in cancer-related signaling pathways. For experimental validation of these genome data, we apply an integrative strategy to characterize previously unreported effectors of activator protein-1 (AP-1) mediated growth and mitogenic response pathways. These studies identify the ADP-ribosylation factor GTPase-activating protein Centaurin α1 and a Tudor domain-containing hypothetical protein as putative AP-1 regulatory oncogenes. These results provide insight into the composition of the AP-1 signaling machinery and validate this approach as a tractable platform for genome-wide functional analysis. PMID:14514886

  9. Anti-inflammatory activity of edible oyster mushroom is mediated through the inhibition of NF-κB and AP-1 signaling

    PubMed Central

    2011-01-01

    Background Mushrooms are well recognized for their culinary properties as well as for their potency to enhance immune response. In the present study, we evaluated anti-inflammatory properties of an edible oyster mushroom (Pleurotus ostreatus) in vitro and in vivo. Methods RAW264.7 murine macrophage cell line and murine splenocytes were incubated with the oyster mushroom concentrate (OMC, 0-100 μg/ml) in the absence or presence of lipopolysacharide (LPS) or concanavalin A (ConA), respectively. Cell proliferation was determined by MTT assay. Expression of cytokines and proteins was measured by ELISA assay and Western blot analysis, respectively. DNA-binding activity was assayed by the gel-shift analysis. Inflammation in mice was induced by intraperitoneal injection of LPS. Results OMC suppressed LPS-induced secretion of tumor necrosis factor-α (TNF-α, interleukin-6 (IL-6), and IL-12p40 from RAW264.7 macrophages. OMC inhibited LPS-induced production of prostaglandin E2 (PGE2) and nitric oxide (NO) through the down-regulation of expression of COX-2 and iNOS, respectively. OMC also inhibited LPS-dependent DNA-binding activity of AP-1 and NF-κB in RAW264.7 cells. Oral administration of OMC markedly suppressed secretion of TNF-α and IL-6 in mice challenged with LPS in vivo. Anti-inflammatory activity of OMC was confirmed by the inhibition of proliferation and secretion of interferon-γ (IFN-γ), IL-2, and IL-6 from concanavalin A (ConA)-stimulated mouse splenocytes. Conclusions Our study suggests that oyster mushroom possesses anti-inflammatory activities and could be considered a dietary agent against inflammation. The health benefits of the oyster mushroom warrant further clinical studies. PMID:21575254

  10. Mir-335 Correlates with Senescence/Aging in Human Mesenchymal Stem Cells and Inhibits their Therapeutic Actions through Inhibition of AP-1 Activity

    PubMed Central

    Tomé, María; Sepúlveda, Juan Carlos; Delgado, Mario; Andrades, José A.; Campisi, Judith; González, Manuel A.; Bernad, Antonio

    2014-01-01

    MicroRNAs (miRNAs), small non-coding RNAs, regulate gene expression primarily at the posttranscriptional level. We previously found that miR-335 is critically involved in the regulation and differentiation capacity of human mesenchymal stem cells (hMSCs) in vitro. In this study, we investigated the significance of miR-335 for the therapeutic potential of hMSCs. Analysis of hMSCs in ex vivo culture demonstrated a significant and progressive increase in miR-335 that is prevented by telomerase. Expression levels of miR-335 were also positively correlated with donor age of hMSCs, and were increased by stimuli that induce cell senescence, such as γ-irradiation and standard O2 concentration. Forced expression of miR-335 resulted in early senescence-like alterations in hMSCs, including: increased SA-β-gal activity and cell size, reduced cell proliferation capacity, augmented levels of p16 protein, and the development of a senescent-associated secretory phenotype (SASP). Furthermore, overexpression of miR-335 abolished the in vivo chondro-osseous potential of hMSCs, and disabled their immunomodulatory capacity in a murine experimental model of lethal endotoxemia. These effects were accompanied by a severely reduced capacity for cell migration in response to pro-inflammatory signals and a marked reduction in Protein Kinase D1 (PRKD1) phosphorylation, resulting in a pronounced decrease of AP-1 activity. Our results demonstrate that miR-335 plays a key role in the regulation of reparative activities of hMSCs and suggests that it might be considered a marker for the therapeutic potency of these cells in clinical applications. PMID:24648336

  11. Opposing Effects of Zac1 and Curcumin on AP-1-Regulated Expressions of S100A7.

    PubMed

    Chu, Yu-Wen; Liu, Shu-Ting; Cheng, Hsiao-Chun; Huang, Shih-Ming; Chang, Yung-Lung; Chiang, Chien-Ping; Liu, Ying-Chun; Wang, Wei-Ming

    2015-01-01

    ZAC, an encoding gene mapped at chromosome 6q24-q25 within PSORS1, was previously found over-expressed in the lower compartment of the hyperplastic epidermis in psoriatic lesions. Cytokines produced in the inflammatory dermatoses may drive AP-1 transcription factor to induce responsive gene expressions. We demonstrated that mZac1 can enhance AP-1-responsive S100A7 expression of which the encoding gene was located in PSORS4 with HaCaT keratinocytes. However, the mZac1-enhanced AP-1 transcriptional activity was suppressed by curcumin, indicating the anti-inflammatory property of this botanical agent and is exhibited by blocking the AP-1-mediated cross-talk between PSORS1 and PSORS4. Two putative AP-1-binding sites were found and demonstrated to be functionally important in the regulation of S100A7 promoter activity. Moreover, we found curcumin reduced the DNA-binding activity of AP-1 to the recognition element located in the S100A7 promoter. The S100A7 expression was found to be upregulated in the lesioned epidermis of atopic dermatitis and psoriasis, which is where this keratinocyte-derived chemoattractant engaged in the pro-inflammatory feedback loop. Understanding the regulatory mechanism of S100A7 expression will be helpful to develop therapeutic strategies for chronic inflammatory dermatoses via blocking the reciprocal stimuli between the inflammatory cells and keratinocytes.

  12. Identification of GATA2 and AP-1 activator elements within the enhancer VNTR occurring in intron 5 of the human SIRT3 gene

    USDA-ARS?s Scientific Manuscript database

    Human SIRT3 gene contains an intronic VNTR enhancer. A T > C transition occurring in the second repeat of each VNTR allele implies the presence/absence of a putative GATA binding motif. A partially overlapping AP-1 site, not affected by the transition, was also identified. Aims of the present study ...

  13. AP-1 overexpression impairs corticosteroid inhibition of collagen production by fibroblasts isolated from asthmatic subjects.

    PubMed

    Jacques, Eric; Semlali, Abdelhabib; Boulet, Louis Philippe; Chakir, Jamila

    2010-08-01

    Asthma is characterized by airway remodeling associated with an increase in the deposition of ECM proteins such as type I collagen. These components are mainly produced by fibroblasts. Inhaled corticosteroids are considered the cornerstone of asthma therapy. Despite substantial evidence as to the anti-inflammatory action of corticosteroids, their effect on controlling ECM protein deposition in the airways is not completely understood. This study determined the effect of dexamethasone (Dex) on collagen production by bronchial fibroblasts derived from asthmatic and healthy subjects. Expression of procollagen mRNA in fibroblasts from asthmatics and normal controls was determined by quantitative PCR. Regulation of the procollagen-alpha(1)I promoter was evaluated by transient transfections. Transforming growth factor-beta (TGF-beta) protein expression was determined by ELISA. Protein expression of glucocorticoid receptor (GR) and interaction with activator protein-1 (AP-1), a collagen regulatory transcription factor, was assessed by Western blots, coimmunoprecipitations, and EMSA. AP-1 overexpression was performed by transient transfection using c-Fos/c-Jun expression plasmids. Dex significantly downregulated procollagen production and promoter activity in normal fibroblasts but had no effect on asthmatic fibroblasts. AP-1 and GR interaction increased after Dex stimulation in asthmatic fibroblasts. AP-1 overexpression in control fibroblasts abrogated collagen gene response to Dex. These results show that Dex failed to reduce collagen production in fibroblasts from asthmatic subjects. This impaired response may be related to AP-1 overexpression in these cells.

  14. Identification and characterization a novel transcription factor activator protein-1 in the sea cucumber Apostichopus japonicus.

    PubMed

    Yang, Limeng; Li, Chenghua; Chang, Yaqing; Gao, Yinxue; Wang, Yi; Wei, Jing; Song, Jian; Sun, Ping

    2015-08-01

    The transcription factor activator protein-1 (AP-1) is an important gene expression regulator with typical Jun and region-leucine zipper (bZIP) domains and can respond to a plethora of physiological and pathological stimulus. In this study, we identified a novel AP-1 gene in Apostichopus japonicus by transcriptome sequencing and RACE approaches (designated as AjAP-1). The full-length of AjAP-1 was of 2944 bp including a 5' untranslated region (UTR) of 201 bp, a 3' UTR of 1753 bp and a putative open reading frame of 990 bp encoding a polypeptide of 329 amino acid residues. Two representative domains of Jun and bZIP as well as two nuclear localization signals (NLSs) were also detected in deduced amino acid of AjAP-1. Spatial distribution expression indicated that AjAP-1 was ubiquitously expressed in all examined tissues with predominant expression in the body wall, moderate in the tube feet, respiratory tree and colemocytes and slightly weak in the intestine and longitudinal muscle. Time-course expression analysis in intestine and coelomocytes revealed that AjAP-1 both reached its peak expression at 4 h after Vibrio splendidus challenge with a 2.6 and 8.2-fold increase compared to their control groups, respectively. Taken together, all these results suggested that AjAP-1 was a novel immune factor and might be involved in the processes of anti-bacteria response in sea cucumber.

  15. Baculovirus p35 gene is oppositely regulated by P53 and AP-1 like factors in Spodoptera frugiperda

    SciTech Connect

    Mohareer, Krishnaveni; Sahdev, Sudhir; Hasnain, Seyed E.

    2011-11-04

    Highlights: Black-Right-Pointing-Pointer Baculovirus p35 is regulated by both viral and host factors. Black-Right-Pointing-Pointer Baculovirus p35 is negatively regulated by SfP53-like factor. Black-Right-Pointing-Pointer Baculovirus p35 is positively regulated by SfAP-1-like factor. -- Abstract: Baculovirus p35 belongs to the early class of genes of AcMNPV and requires viral factors like Immediate Early protein-1 for its transcription. To investigate the role of host factors in regulating p35 gene expression, the putative transcription factor binding sites were examined in silico and the role of these factors in influencing the transcription of p35 gene was assessed. We focused our studies on AP-1 and P53-like factors, which are activated under oxidative stress conditions. The AP-1 motif is located at -1401 while P53 motif is at -1912 relative to p35 translation start site. The predicted AP-1 and P53 elements formed specific complexes with Spodoptera frugiperda nuclear extracts. Both AP-1 and P53 motif binding proteins were down regulated as a function of AcMNPV infection in Spodoptera cells. To address the question whether during an oxidative outburst, the p35 transcription is enhanced; we investigated the role of these oxidative stress induced host transcription factors in influencing p35 gene transcription. Reporter assays revealed that AP-1 element enhances the transcription of p35 by a factor of two. Interestingly, P53 element appears to repress the transcription of p35 gene.

  16. The LIM domain protein nTRIP6 recruits the mediator complex to AP-1-regulated promoters.

    PubMed

    Diefenbacher, Markus E; Reich, Daniela; Dahley, Oliver; Kemler, Denise; Litfin, Margarethe; Herrlich, Peter; Kassel, Olivier

    2014-01-01

    Several LIM domain proteins regulate transcription. They are thought to act through their LIM protein-protein interaction domains as adaptors for the recruitment of transcriptional co-regulators. An intriguing example is nTRIP6, the nuclear isoform of the focal adhesion protein TRIP6. nTRIP6 interacts with AP-1 and enhances its transcriptional activity. nTRIP6 is also essential for the transrepression of AP-1 by the glucocorticoid receptor (GR), by mediating GR tethering to promoter-bound AP-1. Here we report on the molecular mechanism by which nTRIP6 exerts these effects. Both the LIM domains and the pre-LIM region of nTRIP6 are necessary for its co-activator function for AP-1. Discrete domains within the pre-LIM region mediate the dimerization of nTRIP6 at the promoter, which enables the recruitment of the Mediator complex subunits THRAP3 and Med1. This recruitment is blocked by GR, through a competition between GR and THRAP3 for the interaction with the LIM domains of nTRIP6. Thus, nTRIP6 both positively and negatively regulates transcription by orchestrating the recruitment of the Mediator complex to AP-1-regulated promoters.

  17. Interaction of the CDK2-associated protein-1, p12(DOC-1/CDK2AP1), with its homolog, p14(DOC-1R).

    PubMed

    Buajeeb, Waranun; Zhang, Xue; Ohyama, Hiroe; Han, David; Surarit, Rudee; Kim, Yong; Wong, David T W

    2004-03-19

    Human DOC-1/CDK2AP1 gene encodes a growth suppressor protein of 12kDa (p12(DOC-1/CDK2AP1)). Recently, p12(DOC-1/CDK2AP1) has been shown to associate with cell cycle proteins including CDK2 and DNA polymerase alpha/primase. It negatively regulates CDK2 activities and suppresses DNA replication. Therefore, identification of other p12(DOC-1/CDK2AP1) interacting proteins might clarify its role in the cell cycle regulation and carcinogenesis. The purpose of this study was to identify additional p12(DOC-1/CDK2AP1) interacting proteins using the yeast two-hybrid system. Using human p12(DOC-1/CDK2AP1) as a bait in a liver cDNA library screening, cDNA clones identical to human DOC-1R transcript were identified. The interaction between p12(DOC-1/CDK2AP1) and p14(DOC-1R) was verified in vitro and in cells. GST pull-down assay and immunoprecipitation experiments confirmed the interaction between the two proteins. The critical region for p12(DOC-1/CDK2AP1)'s interaction with p14(DOC-1R) was defined to amino acids 20-25 by using a series of deletion mutants as baits in the yeast two-hybrid system. Our data indicated that p12(DOC-1/CDK2AP1) could associate with its homologous protein, p14(DOC-1R).

  18. Identification of novel AP-1 target genes in fibroblasts regulated during cutaneous wound healing.

    PubMed

    Florin, Lore; Hummerich, Lars; Dittrich, Bernd Thilo; Kokocinski, Felix; Wrobel, Gunnar; Gack, Sabine; Schorpp-Kistner, Marina; Werner, Sabine; Hahn, Meinhard; Lichter, Peter; Szabowski, Axel; Angel, Peter

    2004-09-16

    Mesenchymal-epithelial interactions are increasingly considered to be of vital importance for epithelial homeostasis and regeneration. In skin, the transcription factor AP-1 was shown to be critically involved in the communication between keratinocytes and dermal fibroblasts. After skin injury, the release of IL-1 from keratinocytes induces the activity of the AP-1 subunits c-Jun and JunB in fibroblasts leading to a global change in gene expression. To identify AP-1 target genes in fibroblasts, which are involved in the process of cutaneous repair, we performed gene expression profiling of wild-type, c-jun- and junB-deficient fibroblasts in response to IL-1, mimicking the initial phase of wound healing. Using a 15K cDNA collection, over 1000 genes were found to be Jun-dependent and additional 300 clones showed IL-1 responsiveness. Combinatorial evaluation allowed for the dissection of the specific contribution of either AP-1 subunit to gene regulation. Besides previously identified genes that are involved in cutaneous repair, we have identified novel genes regulated during wound healing in vivo and showed their expression by fibroblasts on wound sections. The identification of novel Jun target genes should provide a basis for understanding the molecular mechanisms underlying mesenchymal-epithelial interactions and the critical contribution of AP-1 to tissue homeostasis and repair.

  19. NFATc2 recruits cJun homodimers to an NFAT site to synergistically activate interleukin-2 transcription

    PubMed Central

    Walters, Ryan D.; Drullinger, Linda F.; Kugel, Jennifer F.; Goodrich, James A.

    2013-01-01

    Transcription of interleukin-2 (IL-2), a pivotal cytokine in the mammalian immune response, is induced by NFAT and AP-1 transcriptional activators in stimulated T cells. NFATc2 and cJun drive high levels of synergistic human IL-2 transcription, which requires a unique interaction between the C-terminal activation domain of NFATc2 and cJun homodimers. Here we studied the mechanism by which this interaction contributes to synergistic activation of IL-2 transcription. We found that NFATc2 can recruit cJun homodimers to the −45 NFAT element, which lacks a neighboring AP-1 site. The bZip domain of cJun is sufficient to interact with the C-terminal activation domain of NFATc2 in the absence of DNA and this interaction is inhibited by AP-1 DNA. When the −45 NFAT site was replaced by either a NFAT/AP-1 composite site or a single AP-1 site the specificity for cJun homodimers in synergistically activating IL-2 transcription was lost, and cJun/cFos heterodimers strongly activated transcription. These studies support a model in which IL-2 transcriptional synergy is mediated by the unique recruitment of a cJun homodimer to the −45 NFAT site by NFATc2, where it acts as a co-activator for IL-2 transcription. PMID:23665382

  20. Pterocarpus santalinus L. Regulated Ultraviolet B Irradiation-induced Procollagen Reduction and Matrix Metalloproteinases Expression Through Activation of TGF-β/Smad and Inhibition of the MAPK/AP-1 Pathway in Normal Human Dermal Fibroblasts.

    PubMed

    Gao, Wei; Lin, Pei; Hwang, Eunson; Wang, Yushuai; Yan, Zhengfei; Ngo, Hien T T; Yi, Tae-Hoo

    2017-08-31

    Ultraviolet light-induced reactive oxygen species (ROS) damage human skin and prematurely cause aging. A growing body of research is focusing on considering plants and plant-derived compounds as anti-photoaging therapeutic material. Pterocarpus santalinus L., as an Indian traditional medicine, possesses antidiabetic, anti-inflammatory and antioxidative effects. Here, we studied the anti-photoaging effects of ethanolic extract of P. santalinus L. heartwood (EPS) on ultraviolet radiation B (UVB)-irradiated normal human dermal fibroblasts (NHDFs). Results showed that EPS significantly inhibited the upregulation of matrix metalloproteinases and IL-6 caused by UVB irradiation, and suppressed UVB-induced phosphorylation of extracellular signal-regulated kinase, Jun N-terminal kinase, and p38, as well as the activation of AP-1 transcription factors. Further study indicated that UVB-induced production of MMP-1 and IL-6 could be inhibit by PD 98059 (an ERK inhibitor) and SP600125 (A JNK inhibitor), implied that EPS inhibited UVB-induced MMP-1 and IL-6 secretion by inactivating MAPK signaling pathway. In addition, EPS possessed an excellent antioxidant activity, which could increase cytoprotective antioxidants such as HO-1, NQ-O1 expression by facilitating the nuclear accumulation of Nrf2. Treatment of NHDFs with EPS also recovered UVB-induced procollagen type I reduction by activating TGF-β/Smad pathway. These findings demonstrated that EPS had a potential effect against UVB-induced skin photoaging. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. Anti-cancer effect of snake venom toxin through down regulation of AP-1 mediated PRDX6 expression.

    PubMed

    Lee, Hye Lim; Park, Mi Hee; Son, Dong Ju; Song, Ho Sueb; Kim, Jung Hyun; Ko, Seong Cheol; Song, Min Jong; Lee, Won Hyoung; Yoon, Joo Hee; Ham, Young Wan; Han, Sang Bae; Hong, Jin Tae

    2015-09-08

    Snake venom toxin (SVT) from Vipera lebetina turanica contains a mixture of different enzymes and proteins. Peroxiredoxin 6 (PRDX6) is known to be a stimulator of lung cancer cell growth. PRDX6 is a member of peroxidases, and has calcium-independent phospholipase A2 (iPLA2) activities. PRDX6 has an AP-1 binding site in its promoter region of the gene. Since AP-1 is implicated in tumor growth and PRDX6 expression, in the present study, we investigated whether SVT inhibits PRDX6, thereby preventing human lung cancer cell growth (A549 and NCI-H460) through inactivation of AP-1. A docking model study and pull down assay showed that SVT completely fits on the basic leucine zipper (bZIP) region of c-Fos of AP-1. SVT (0-10 μg/ml) inhibited lung cancer cell growth in a concentration dependent manner through induction of apoptotic cell death accompanied by induction of cleaved caspase-3, -8, -9, Bax, p21 and p53, but decreased cIAP and Bcl2 expression via inactivation of AP-1. In an xenograft in vivo model, SVT (0.5 mg/kg and 1 mg/kg) also inhibited tumor growth accompanied with the reduction of PRDX6 expression, but increased expression of proapoptotic proteins. These data indicate that SVT inhibits tumor growth via inhibition of PRDX6 activity through interaction with its transcription factor AP-1.

  2. Activator protein 1 promotes the transcriptional activation of IRAK-M.

    PubMed

    Jin, Peipei; Bo, Lulong; Liu, Yongjian; Lu, Wenbin; Lin, Shengwei; Bian, Jinjun; Deng, Xiaoming

    2016-10-01

    Interleukin-1 receptor-associated kinase M (IRAK-M) is a well-known negative regulator for Toll-like receptor signaling, which can regulate immune homeostasis and tolerance in a number of pathological settings. However, the mechanism for IRAK-M regulation at transcriptional level remains largely unknown. In this study, a 1.4kb upstream sequence starting from the major IRAK-M transcriptional start site was cloned into luciferase reporter vector pGL3-basic to construct the full-length IRAK-M promoter. Luciferase reporter plasmids harboring the full-length and the deletion mutants of IRAK-M were transfected into 293T and A549 cells, and their relative luciferase activity was measured. The results demonstrated that activator protein 1(AP-1) cis-element plays a crucial role in IRAK-M constitutive gene transcription. Silencing of c-Fos and/or c-Jun expression suppressed the IRAK-M promoter activity as well as its mRNA and protein expressions. As a specific inhibitor for AP-1 activation, SP600125 also significantly suppressed the basal transcriptional activity of IRAK-M, the binding activity of c-Fos/c-Jun with IRAK-M promoter, and IRAK-M protein expression. Taken together, the result of this study highlights the importance of AP-1 in IRAK-M transcription, which offers more information on the role of IRAK-M in infectious and non-infectious diseases.

  3. A novel AP-1/miR-101 regulatory feedback loop and its implication in the migration and invasion of hepatoma cells.

    PubMed

    Liu, Jing-Jing; Lin, Xue-Jia; Yang, Xiao-Jing; Zhou, Liangji; He, Shuai; Zhuang, Shi-Mei; Yang, Jine

    2014-10-29

    MicroRNA-101 (miR-101) is frequently downregulated in various cancers. To date, the regulatory networks of miR-101 remain obscure. In this study, we demonstrated that miR-101 was mainly transcribed from human miR-101-2 and mouse miR-101bgene loci. Subsequent analyses revealed that activator protein-1 (AP-1) directly binded to the -17.4 to -16.4 k region upstream of pre-miR-101-2 and activated the expression of miR-101. On the other hand, miR-101 could inhibit the expression of ERK2 and c-Fos, two key factors of the AP-1 pathway, by binding to their 3'-UTRs. Furthermore, reintroduction of miR-101 efficiently suppressed the AP-1 activity and pri-miR-101-2 transcription. These data thus suggest a novel AP-1/miR-101 regulatory circuitry, that is, AP-1 promotes the transcription of miR-101, whereas the expression of miR-101 reduces the level of ERK2 and c-Fos and thereby attenuates the AP-1 signaling. Further investigation disclosed that the AP-1 activator TPA-induced MMP9 activity and the TPA-promoted migration and invasion of hepatoma cells were significantly attenuated by miR-101 but were enhanced by miR-101 inhibitor. Our results suggest that the AP-1/miR-101 feedback loop may prevent the excessive activation of metastatic signals imposed by ERK2/AP-1 and highlight the biological significance of miR-101 downregulation in cancer metastasis.

  4. Catalytically defective receptor protein tyrosine kinase PTK7 enhances invasive phenotype by inducing MMP-9 through activation of AP-1 and NF-κB in esophageal squamous cell carcinoma cells

    PubMed Central

    Shin, Won-Sik; Hong, Yuri; Lee, Hae Won; Lee, Seung-Taek

    2016-01-01

    Protein tyrosine kinase 7 (PTK7), a member of the catalytically defective receptor protein tyrosine kinase family, is upregulated in various cancers including esophageal squamous cell carcinoma (ESCC). Here, we have explored the molecular mechanism of PTK7-dependent invasiveness in ESCC cells. PTK7 knockdown reduced gelatin degradation and MMP-9 secretion in cultures of ESCC TE-10 cells, and showed reduced levels of MMP9 mRNA using real-time RT-PCR and luciferase reporter assays. PTK7 knockdown decreased not only phosphorylation of NF-κB, IκB, ERK, and JNK, but also nuclear localization of NF-κB and AP-1 consisting of c-Fos and c-Jun. Activation of AP-1 and NF-κB requires PTK7-mediated activation of tyrosine kinases, including Src. In addition, NF-κB activation by PTK7 involves the PI3K/Akt signaling pathway. PTK7-mediated upregulation of MMP9 was also observed in other ESCC cell lines and in three-dimensional cultures of TE-10 cells. Moreover, MMP-9 expression positively correlated with PTK7 expression in ESCC tumor tissue. These findings demonstrate that PTK7 upregulates MMP9 through activation of AP-1 and NF-κB and, thus increases invasive properties of ESCC cells. PMID:27689325

  5. Regulation of Hspb7 by MEF2 and AP-1: implications for Hspb7 in muscle atrophy.

    PubMed

    Tobin, Stephanie Wales; Yang, Dabo; Girgis, John; Farahzad, Ali; Blais, Alexandre; McDermott, John C

    2016-11-01

    Mycocyte enhancer factor 2 (MEF2) and activator protein 1 (AP-1) transcription complexes have been individually implicated in myogenesis, but their genetic interaction has not previously been addressed. Using MEF2A, c-Jun and Fra-1 chromatin immunoprecipitation sequencing (ChIP-seq) data and predicted AP-1 consensus motifs, we identified putative common MEF2 and AP-1 target genes, several of which are implicated in regulating the actin cytoskeleton. Because muscle atrophy results in remodelling or degradation of the actin cytoskeleton, we characterized the expression of putative MEF2 and AP-1 target genes (Dstn, Flnc, Hspb7, Lmod3 and Plekhh2) under atrophic conditions using dexamethasone (Dex) treatment in skeletal myoblasts. Heat shock protein b7 (Hspb7) was induced by Dex treatment and further analyses revealed that loss of MEF2A using siRNA prevented Dex-regulated induction of Hspb7. Conversely, ectopic Fra-2 or c-Jun expression reduced Dex-mediated upregulation of Hspb7 whereas AP-1 depletion enhanced Hspb7 expression. In vivo, expression of Hspb7 and other autophagy-related genes was upregulated in response to atrophic conditions in mice. Manipulation of Hspb7 levels in mice also impacted gross muscle mass. Collectively, these data indicate that MEF2 and AP-1 confer antagonistic regulation of Hspb7 gene expression in skeletal muscle, with implications for autophagy and muscle atrophy.

  6. Pycnogenol Attenuates the Release of Proinflammatory Cytokines and Expression of Perilipin 2 in Lipopolysaccharide-Stimulated Microglia in Part via Inhibition of NF-κB and AP-1 Activation.

    PubMed

    Fan, Bin; Dun, Sai-Hong; Gu, Jian-Qiu; Guo, Yang; Ikuyama, Shoichiro

    2015-01-01

    Over activation of microglia results in the production of proinflammatory agents that have been implicated in various brain diseases. Pycnogenol is a patented extract from French maritime pine bark (Pinus pinaster Aiton) with strong antioxidant and anti-inflammatory potency. The present study investigated whether pycnogenol may be associated with the production of proinflammatory mediators in lipopolysaccharide-stimulated BV2 (mouse-derived) microglia. It was found that pycnogenol treatment was dose-dependently associated with significantly less release of nitricoxide (NO), TNF-α, IL-6 and IL-1β, and lower levels of intercellular adhesion molecule1 (ICAM-1) and perilipin 2 (PLIN2). Furthermore, this effect was replicated in primary brain microglia. Levels of inducible NO synthase mRNA and protein were attenuated, whereas there was no change in the production of the anti-inflammatory cytokine IL-10. Further evidence indicated that pycnogenol treatment led to the suppression of NF-κB activation through inhibition of p65 translocation into the nucleus and inhibited DNA binding of AP-1, suggesting that these proinflammatory factors are associated with NF-κB and AP-1. We conclude that pycnogenol exerts anti-inflammatory effects through inhibition of the NF-κB and AP-1pathway, and may be useful as a therapeutic agent in the prevention of diseases caused by over activation of microglia.

  7. Genome-wide association between YAP/TAZ/TEAD and AP-1 at enhancers drives oncogenic growth.

    PubMed

    Zanconato, Francesca; Forcato, Mattia; Battilana, Giusy; Azzolin, Luca; Quaranta, Erika; Bodega, Beatrice; Rosato, Antonio; Bicciato, Silvio; Cordenonsi, Michelangelo; Piccolo, Stefano

    2015-09-01

    YAP/TAZ are nuclear effectors of the Hippo pathway regulating organ growth and tumorigenesis. Yet, their function as transcriptional regulators remains underinvestigated. By ChIP-seq analyses in breast cancer cells, we discovered that the YAP/TAZ transcriptional response is pervasively mediated by a dual element: TEAD factors, through which YAP/TAZ bind to DNA, co-occupying chromatin with activator protein-1 (AP-1, dimer of JUN and FOS proteins) at composite cis-regulatory elements harbouring both TEAD and AP-1 motifs. YAP/TAZ/TEAD and AP-1 form a complex that synergistically activates target genes directly involved in the control of S-phase entry and mitosis. This control occurs almost exclusively from distal enhancers that contact target promoters through chromatin looping. YAP/TAZ-induced oncogenic growth is strongly enhanced by gain of AP-1 and severely blunted by its loss. Conversely, AP-1-promoted skin tumorigenesis is prevented in YAP/TAZ conditional knockout mice. This work highlights a new layer of signalling integration, feeding on YAP/TAZ function at the chromatin level.

  8. Quercetin Inhibits Left Ventricular Hypertrophy in Spontaneously Hypertensive Rats and Inhibits Angiotensin II-Induced H9C2 Cells Hypertrophy by Enhancing PPAR-γ Expression and Suppressing AP-1 Activity

    PubMed Central

    Yan, Lei; Zhang, Ji Dong; Wang, Bo; Lv, Yi Jing; Jiang, Hong; Liu, Gui Lin; Qiao, Yun; Ren, Ming; Guo, Xue Feng

    2013-01-01

    Background Quercetin is the most abundant flavonoid in fruit and vegetables and is believed to attenuate cardiovascular disease. We hypothesized that quercetin inhibits cardiac hypertrophy by blocking AP-1 (c-fos, c-jun) and activating PPAR-γ signaling pathways. Methodology/Principal Findings The aim of this study was to identify the mechanism underlying quercetin-mediated attenuation of cardiac hypertrophy. Quercetin therapy reduced blood pressure and markedly reduced the ratio of left ventricular to body weight (LVW/BW) (P<0.05, vs. spontaneously hypertensive rats (SHRs)). In vitro, quercetin also significantly attenuated Ang II-induced H9C2 cells hypertrophy, as indicated by its concentration dependent inhibitory effects on [3H]leucine incorporation into H9C2 cells (64% reduction) and by the reduced hypertrophic surface area in H9C2 cells compared with the Ang II group (P<0.01, vs. Ang II group). Concurrently, we found that PPAR-γ activity was significantly increased in the quercetin-treated group both in vivo and in vitro when analyzed using immunofluorescent or immunohistochemical assays (P<0.05, vs. SHRs or P<0.01, vs. the Ang II group). Conversely, in vivo, AP-1 (c-fos, s-jun) activation was suppressed in the quercetin-treated group, as was the downstream hypertrophy gene, including mRNA levels of ANP and BNP (P<0.05, vs. SHRs). Additionally, both western blotting and real time-PCR demonstrated that PPAR-γ protein and mRNA were increased in the myocardium and AP-1 protein and mRNA were significantly decreased in the quercetin-treated group (P<0.05, vs. SHRs). Furthermore, western blotting and real time-PCR analyses also showed that transfection with PPAR-γ siRNA significantly increased AP-1 signaling and reversed the effects of quercetin inhibition on mRNA expression levels of genes such as ANP and BNP in hypertrophic H9C2 cells. Conclusions Our data indicate that quercetin may inhibit cardiac hypertrophy by enhancing PPAR-γ expression and by

  9. Integrated omic analysis of oropharyngeal carcinomas reveals human papillomavirus (HPV)-dependent regulation of the activator protein 1 (AP-1) pathway.

    PubMed

    Sepiashvili, Lusia; Waggott, Daryl; Hui, Angela; Shi, Wei; Su, Susie; Ignatchenko, Alex; Ignatchenko, Vladimir; Laureano, Marissa; Huang, Shao Hui; Xu, Wei; Weinreb, Ilan; Waldron, John; O'Sullivan, Brian; Irish, Jonathan C; Boutros, Paul C; Liu, Fei-Fei; Kislinger, Thomas

    2014-12-01

    HPV-positive oropharyngeal carcinoma (OPC) patients have superior outcomes relative to HPV-negative patients, but the underlying mechanisms remain poorly understood. We conducted a proteomic investigation of HPV-positive (n = 27) and HPV-negative (n = 26) formalin-fixed paraffin-embedded OPC biopsies to acquire insights into the biological pathways that correlate with clinical behavior. Among the 2,633 proteins identified, 174 were differentially abundant. These were enriched for proteins related to cell cycle, DNA replication, apoptosis, and immune response. The differential abundances of cortactin and methylthioadenosine phosphorylase were validated by immunohistochemistry in an independent cohort of 29 OPC samples (p = 0.023 and p = 0.009, respectively). An additional 1,124 proteins were independently corroborated through comparison to a published proteomic dataset of OPC. Furthermore, utilizing the Cancer Genome Atlas, we conducted an integrated investigation of OPC, attributing mechanisms underlying differential protein abundances to alterations in mutation, copy number, methylation, and mRNA profiles. A key finding of this integration was the identification of elevated cortactin oncoprotein levels in HPV-negative OPCs. These proteins might contribute to reduced survival in these patients via their established role in radiation resistance. Through interrogation of Cancer Genome Atlas data, we demonstrated that activation of the β1-integrin/FAK/cortactin/JNK1 signaling axis and associated differential regulation of activator protein 1 transcription factor target genes are plausible consequences of elevated cortactin protein levels.

  10. Expression of I2PP2A, an inhibitor of protein phosphatase 2A, induces c-Jun and AP-1 activity.

    PubMed Central

    Al-Murrani, S W; Woodgett, J R; Damuni, Z

    1999-01-01

    Transient expression of I2PP2A, a potent inhibitor of protein phosphatase 2A (PP2A), in HEK-293 cells increased the concentration and DNA binding of the proto-oncogene c-Jun. In contrast, expression of the catalytic subunit of PP2A (PP2AC) markedly decreased the concentration and DNA binding of c-Jun. Expression of I2PP2A also increased the transcriptional activity of activator protein-1, and this effect was diminished in a dose-dependent manner by expression of PP2AC. Densitometric analysis following Western blotting of extracts with antibodies specific for phospho-Ser63 and Ser73 suggests that the effects of I2PP2A and PP2AC expression might be mediated, in part, by changes in the phosphorylation of c-Jun at Ser63. The results indicate that I2PP2A elicits effects that are consistent with it acting as an inhibitor of PP2A in intact cells, and suggest that PP2A might exhibit site selectivity with respect to c-Jun phosphorylation. PMID:10393085

  11. Expression of I2PP2A, an inhibitor of protein phosphatase 2A, induces c-Jun and AP-1 activity.

    PubMed

    Al-Murrani, S W; Woodgett, J R; Damuni, Z

    1999-07-15

    Transient expression of I2PP2A, a potent inhibitor of protein phosphatase 2A (PP2A), in HEK-293 cells increased the concentration and DNA binding of the proto-oncogene c-Jun. In contrast, expression of the catalytic subunit of PP2A (PP2AC) markedly decreased the concentration and DNA binding of c-Jun. Expression of I2PP2A also increased the transcriptional activity of activator protein-1, and this effect was diminished in a dose-dependent manner by expression of PP2AC. Densitometric analysis following Western blotting of extracts with antibodies specific for phospho-Ser63 and Ser73 suggests that the effects of I2PP2A and PP2AC expression might be mediated, in part, by changes in the phosphorylation of c-Jun at Ser63. The results indicate that I2PP2A elicits effects that are consistent with it acting as an inhibitor of PP2A in intact cells, and suggest that PP2A might exhibit site selectivity with respect to c-Jun phosphorylation.

  12. Integrated Omic Analysis of Oropharyngeal Carcinomas Reveals Human Papillomavirus (HPV)–dependent Regulation of the Activator Protein 1 (AP-1) Pathway*

    PubMed Central

    Sepiashvili, Lusia; Waggott, Daryl; Hui, Angela; Shi, Wei; Su, Susie; Ignatchenko, Alex; Ignatchenko, Vladimir; Laureano, Marissa; Huang, Shao Hui; Xu, Wei; Weinreb, Ilan; Waldron, John; O'Sullivan, Brian; Irish, Jonathan C.; Boutros, Paul C.; Liu, Fei-Fei; Kislinger, Thomas

    2014-01-01

    HPV-positive oropharyngeal carcinoma (OPC) patients have superior outcomes relative to HPV-negative patients, but the underlying mechanisms remain poorly understood. We conducted a proteomic investigation of HPV-positive (n = 27) and HPV-negative (n = 26) formalin-fixed paraffin-embedded OPC biopsies to acquire insights into the biological pathways that correlate with clinical behavior. Among the 2,633 proteins identified, 174 were differentially abundant. These were enriched for proteins related to cell cycle, DNA replication, apoptosis, and immune response. The differential abundances of cortactin and methylthioadenosine phosphorylase were validated by immunohistochemistry in an independent cohort of 29 OPC samples (p = 0.023 and p = 0.009, respectively). An additional 1,124 proteins were independently corroborated through comparison to a published proteomic dataset of OPC. Furthermore, utilizing the Cancer Genome Atlas, we conducted an integrated investigation of OPC, attributing mechanisms underlying differential protein abundances to alterations in mutation, copy number, methylation, and mRNA profiles. A key finding of this integration was the identification of elevated cortactin oncoprotein levels in HPV-negative OPCs. These proteins might contribute to reduced survival in these patients via their established role in radiation resistance. Through interrogation of Cancer Genome Atlas data, we demonstrated that activation of the β1-integrin/FAK/cortactin/JNK1 signaling axis and associated differential regulation of activator protein 1 transcription factor target genes are plausible consequences of elevated cortactin protein levels. PMID:25271301

  13. Functional Characterization of OsMADS18, a Member of the AP1/SQUA Subfamily of MADS Box Genes1[w

    PubMed Central

    Fornara, Fabio; Pařenicová, Lucie; Falasca, Giuseppina; Pelucchi, Nilla; Masiero, Simona; Ciannamea, Stefano; Lopez-Dee, Zenaida; Altamura, Maria Maddalena; Colombo, Lucia; Kater, Martin M.

    2004-01-01

    MADS box transcription factors controlling flower development have been isolated and studied in a wide variety of organisms. These studies have shown that homologous MADS box genes from different species often have similar functions. OsMADS18 from rice (Oryza sativa) belongs to the phylogenetically defined AP1/SQUA group. The MADS box genes of this group have functions in plant development, like controlling the transition from vegetative to reproductive growth, determination of floral organ identity, and regulation of fruit maturation. In this paper we report the functional analysis of OsMADS18. This rice MADS box gene is widely expressed in rice with its transcripts accumulated to higher levels in meristems. Overexpression of OsMADS18 in rice induced early flowering, and detailed histological analysis revealed that the formation of axillary shoot meristems was accelerated. Silencing of OsMADS18 using an RNA interference approach did not result in any visible phenotypic alteration, indicating that OsMADS18 is probably redundant with other MADS box transcription factors. Surprisingly, overexpression of OsMADS18 in Arabidopsis caused a phenotype closely resembling the ap1 mutant. We show that the ap1 phenotype is not caused by down-regulation of AP1 expression. Yeast two-hybrid experiments showed that some of the natural partners of AP1 interact with OsMADS18, suggesting that the OsMADS18 overexpression phenotype in Arabidopsis is likely to be due to the subtraction of AP1 partners from active transcription complexes. Thus, when compared to AP1, OsMADS18 during evolution seems to have conserved the mechanistic properties of protein-protein interactions, although it cannot complement the AP1 function. PMID:15299121

  14. Brain suppression of AP-1 by inhaled diesel exhaust and reversal by cerium oxide nanoparticles.

    PubMed

    Lung, Shyang; Cassee, Flemming R; Gosens, Ilse; Campbell, Arezoo

    2014-08-01

    One of the uses of cerium oxide nanoparticles (nanoceria, CeO2) is as a diesel fuel additive to improve fuel efficiency. Gene/environment interactions are important determinants in the etiology of age-related disorders. Thus, it is possible that individuals on high-fat diet and genetic predisposition to vascular disease may be more vulnerable to the adverse health effects of particle exposure. The aim of this pilot study was to test the hypothesis that inhalation of diesel exhaust (DE) or diesel exhaust-containing cerium oxide nanoparticles (DCeE) induces stress in the brain of a susceptible animal model. Atherosclerotic prone, apolipoprotein E knockout (ApoE(-/-)) mice fed a high-fat diet, were exposed by inhalation to purified air (control), DE or DCeE. The stress-responsive transcription factor, activator protein-1 (AP-1), was significantly decreased in the cortical and subcortical fraction of the brain after DE exposure. The addition of nanoceria to the diesel fuel reversed this effect. The activation of another stress-related transcription factor (NF-κB) was not inhibited. AP-1 is composed of complexes of the Jun and/or Fos family of proteins. Exposure to DCeE caused c-Jun activation and this may be a mechanism by which addition of nanoceria to the fuel reversed the effect of DE exposure on AP-1 activation. This pilot study demonstrates that exposure to DE does impact the brain and addition of nanoceria may be protective. However, more extensive studies are necessary to determine how DE induced reduction of AP-1 activity and compensation by nanoceria impacts normal function of the brain.

  15. Multiple facets of junD gene expression are atypical among AP-1 family members

    PubMed Central

    Hernandez, JM; Floyd, DH; Weilbaecher, KN; Green, PL; Boris-Lawrie, K

    2009-01-01

    JunD is a versatile AP-1 transcription factor that can activate or repress a diverse collection of target genes. Precise control of junD expression and JunD protein–protein interactions modulate tumor angiogenesis, cellular differentiation, proliferation and apoptosis. Molecular and clinical knowledge of two decades has revealed that precise JunD activity is elaborated by interrelated layers of constitutive transcriptional control, complex post-transcriptional regulation and a collection of post-translational modifications and protein–protein interactions. The stakes are high, as inappropriate JunD activity contributes to neoplastic, metabolic and viral diseases. This article deconvolutes multiple layers of control that safeguard junD gene expression and functional activity. The activity of JunD in transcriptional activation and repression is integrated into a regulatory network by which JunD exerts a pivotal role in cellular growth control. Our discussion of the JunD regulatory network integrates important open issues and posits new therapeutic targets for the neoplastic, metabolic and viral diseases associated with JunD/AP-1 expression. PMID:18427548

  16. AP-1 proteins in the adult brain: facts and fiction about effectors of neuroprotection and neurodegeneration.

    PubMed

    Herdegen, T; Waetzig, V

    2001-04-30

    Jun and Fos proteins are induced and activated following most physiological and pathophysiological stimuli in the brain. Only few data allow conclusions about distinct functions of AP-1 proteins in neurodegeneration and neuroregeneration, and these functions mainly refer to c-Jun and its activation by JNKs. Apoptotic functions of activated c-Jun affect hippocampal, nigral and primary cultured neurons following excitotoxic stimulation and destruction of the neuron-target-axis including withdrawal of trophic molecules. The inhibition of JNKs might exert neuroprotection by subsequent omission of c-Jun activation. Besides endogenous neuronal functions, the c-Jun/AP-1 proteins can damage the nervous system by upregulation of harmful programs in non-neuronal cells (e.g. microglia) with release of neurodegenerative molecules. In contrast, the differentiation with neurite extension and maturation of neural cells in vitro indicate physiological and potentially neuroprotective functions of c-Jun and JNKs including sensoring for alterations in the cytoskeleton. This review summarizes the multiple molecular interfunctions which are involved in the shift from the physiological role to degenerative effects of the Jun/JNK-axis such as cell type-specific expression and intracellular localization of scaffold proteins and upstream activators, antagonistic phosphatases, interaction with other kinase systems, or the activation of transcription factors competing for binding to JNK proteins and AP-1 DNA elements.

  17. Fos and jun cooperate in transcriptional regulation via heterologous activation domains.

    PubMed Central

    Abate, C; Luk, D; Gagne, E; Roeder, R G; Curran, T

    1990-01-01

    The products of c-fos and c-jun (Fos and Jun) function in gene regulation by interacting with the AP-1 binding site. Here we have examined the contribution of Fos and Jun toward transcriptional activity by using Fos and Jun polypeptides purified from Escherichia coli. Fos contained a transcriptional activation domain as well as a region which exerted a negative influence on transcriptional activity in vitro. Moreover, distinct activation domains in both Fos and Jun functioned cooperatively in transcriptional stimulation. Thus, regulation of gene expression by Fos and Jun results from an integration of several functional domains in a bimolecular complex. Images PMID:2119000

  18. JUNB/AP-1 controls IFN-γ during inflammatory liver disease

    PubMed Central

    Thomsen, Martin K.; Bakiri, Latifa; Hasenfuss, Sebastian C.; Hamacher, Rainer; Martinez, Lola; Wagner, Erwin F.

    2013-01-01

    Understanding the molecular pathogenesis of inflammatory liver disease is essential to design efficient therapeutic approaches. In hepatocytes, the dimeric transcription factor c-JUN/AP-1 is a major mediator of cell survival during hepatitis, although functions for other JUN proteins in liver disease are less defined. Here, we found that JUNB was specifically expressed in human and murine immune cells during acute liver injury. We analyzed the molecular function of JUNB in experimental models of hepatitis, including administration of concanavalin A (ConA) or α-galactosyl-ceramide, which induce liver inflammation and injury. Mice specifically lacking JUNB in hepatocytes displayed a mild increase in ConA-induced liver damage. However, targeted deletion of Junb in immune cells and hepatocytes protected against hepatitis in experimental models that involved NK/NKT cells. The absence of JUNB in immune cells decreased IFN-γ expression and secretion from NK and NKT cells, leading to reduced STAT1 pathway activation. Systemic IFN-γ treatment or adenovirus-based IRF1 delivery to Junb-deficient mice restored hepatotoxicity, and we demonstrate that Ifng is a direct transcriptional target of JUNB. These findings demonstrate that JUNB/AP-1 promotes cell death during acute hepatitis by regulating IFN-γ production in NK and NKT cells and thus functionally antagonizes the hepatoprotective function of c-JUN/AP-1 in hepatocytes. PMID:24200694

  19. Altered activities of transcription factors and their related gene expression in cardiac tissues of diabetic rats.

    PubMed

    Nishio, Y; Kashiwagi, A; Taki, H; Shinozaki, K; Maeno, Y; Kojima, H; Maegawa, H; Haneda, M; Hidaka, H; Yasuda, H; Horiike, K; Kikkawa, R

    1998-08-01

    Gene regulation in the cardiovascular tissues of diabetic subjects has been reported to be altered. To examine abnormal activities in transcription factors as a possible cause of this altered gene regulation, we studied the activity of two redox-sensitive transcription factors--nuclear factor-kappaB (NF-kappaB) and activating protein-1 (AP-1)--and the change in the mRNA content of heme oxygenase-1, which is regulated by these transcription factors in the cardiac tissues of rats with streptozotocin-induced diabetes. Increased activity of NF-kappaB and AP-1 but not nuclear transcription-activating factor, as determined by an electrophoretic mobility shift assay, was found in the hearts of 4-week diabetic rats. Glycemic control by a subcutaneous injection of insulin prevented these diabetes-induced changes in transcription factor activity. In accordance with these changes, the mRNA content of heme oxygenase-1 was increased fourfold in 4-week diabetic rats and threefold in 24-week diabetic rats as compared with control rats (P < 0.01 and P < 0.05, respectively). Insulin treatment also consistently prevented changes in the mRNA content of heme oxygenase-1. The oral administration of an antioxidant, probucol, to these diabetic rats partially prevented the elevation of the activity of both NF-kappaB and AP-1, and normalized the mRNA content of heme oxygenase-1 without producing any change in the plasma glucose concentration. These results suggest that elevated oxidative stress is involved in the activation of the transcription factors NF-kappaB and AP-1 in the cardiac tissues of diabetic rats, and that these abnormal activities of transcription factors could be associated with the altered gene regulation observed in the cardiovascular tissues of diabetic rats.

  20. Loss-of-Function Mutations in YY1AP1 Lead to Grange Syndrome and a Fibromuscular Dysplasia-Like Vascular Disease.

    PubMed

    Guo, Dong-Chuan; Duan, Xue-Yan; Regalado, Ellen S; Mellor-Crummey, Lauren; Kwartler, Callie S; Kim, Dong; Lieberman, Kenneth; de Vries, Bert B A; Pfundt, Rolph; Schinzel, Albert; Kotzot, Dieter; Shen, Xuetong; Yang, Min-Lee; Bamshad, Michael J; Nickerson, Deborah A; Gornik, Heather L; Ganesh, Santhi K; Braverman, Alan C; Grange, Dorothy K; Milewicz, Dianna M

    2017-01-05

    Fibromuscular dysplasia (FMD) is a heterogeneous group of non-atherosclerotic and non-inflammatory arterial diseases that primarily involves the renal and cerebrovascular arteries. Grange syndrome is an autosomal-recessive condition characterized by severe and early-onset vascular disease similar to FMD and variable penetrance of brachydactyly, syndactyly, bone fragility, and learning disabilities. Exome-sequencing analysis of DNA from three affected siblings with Grange syndrome identified compound heterozygous nonsense variants in YY1AP1, and homozygous nonsense or frameshift YY1AP1 variants were subsequently identified in additional unrelated probands with Grange syndrome. YY1AP1 encodes yin yang 1 (YY1)-associated protein 1 and is an activator of the YY1 transcription factor. We determined that YY1AP1 localizes to the nucleus and is a component of the INO80 chromatin remodeling complex, which is responsible for transcriptional regulation, DNA repair, and replication. Molecular studies revealed that loss of YY1AP1 in vascular smooth muscle cells leads to cell cycle arrest with decreased proliferation and increased levels of the cell cycle regulator p21/WAF/CDKN1A and disrupts TGF-β-driven differentiation of smooth muscle cells. Identification of YY1AP1 mutations as a cause of FMD indicates that this condition can result from underlying genetic variants that significantly alter the phenotype of vascular smooth muscle cells.

  1. Pentraxin-2 suppresses c-Jun/AP-1 signaling to inhibit progressive fibrotic disease

    PubMed Central

    Nakagawa, Naoki; Gomez, Ivan G.; Johnson, Bryce G.; Kameoka, Sei; Jack, Richard M.; Lupher, Mark L.; Gharib, Sina A.; Duffield, Jeremy S.

    2016-01-01

    Pentraxin-2 (PTX-2), also known as serum amyloid P component (SAP/APCS), is a constitutive, antiinflammatory, innate immune plasma protein whose circulating level is decreased in chronic human fibrotic diseases. Here we show that recombinant human PTX-2 (rhPTX-2) retards progression of chronic kidney disease in Col4a3 mutant mice with Alport syndrome, reducing blood markers of kidney failure, enhancing lifespan by 20%, and improving histological signs of disease. Exogenously delivered rhPTX-2 was detected in macrophages but also in tubular epithelial cells, where it counteracted macrophage activation and was cytoprotective for the epithelium. Computational analysis of genes regulated by rhPTX-2 identified the transcriptional regulator c-Jun along with its activator protein–1 (AP-1) binding partners as a central target for the function of rhPTX-2. Accordingly, PTX-2 attenuates c-Jun and AP-1 activity, and reduces expression of AP-1–dependent inflammatory genes in both monocytes and epithelium. Our studies therefore identify rhPTX-2 as a potential therapy for chronic fibrotic disease of the kidney and an important inhibitor of pathological c-Jun signaling in this setting. PMID:27942582

  2. Pentraxin-2 suppresses c-Jun/AP-1 signaling to inhibit progressive fibrotic disease.

    PubMed

    Nakagawa, Naoki; Barron, Luke; Gomez, Ivan G; Johnson, Bryce G; Roach, Allie M; Kameoka, Sei; Jack, Richard M; Lupher, Mark L; Gharib, Sina A; Duffield, Jeremy S

    2016-12-08

    Pentraxin-2 (PTX-2), also known as serum amyloid P component (SAP/APCS), is a constitutive, antiinflammatory, innate immune plasma protein whose circulating level is decreased in chronic human fibrotic diseases. Here we show that recombinant human PTX-2 (rhPTX-2) retards progression of chronic kidney disease in Col4a3 mutant mice with Alport syndrome, reducing blood markers of kidney failure, enhancing lifespan by 20%, and improving histological signs of disease. Exogenously delivered rhPTX-2 was detected in macrophages but also in tubular epithelial cells, where it counteracted macrophage activation and was cytoprotective for the epithelium. Computational analysis of genes regulated by rhPTX-2 identified the transcriptional regulator c-Jun along with its activator protein-1 (AP-1) binding partners as a central target for the function of rhPTX-2. Accordingly, PTX-2 attenuates c-Jun and AP-1 activity, and reduces expression of AP-1-dependent inflammatory genes in both monocytes and epithelium. Our studies therefore identify rhPTX-2 as a potential therapy for chronic fibrotic disease of the kidney and an important inhibitor of pathological c-Jun signaling in this setting.

  3. NRF-1, and AP-1 regulate the promoter of the human calpain small subunit 1 (CAPNS1) gene.

    PubMed

    Asangani, Irfan A; Rasheed, Suhail A K; Leupold, Jörg H; Post, Stefan; Allgayer, Heike

    2008-02-29

    Ubiquitously expressed micro- and m-calpain are cysteine proteases with broad functions in cell spreading, migration, proliferation, apoptosis, and in tumor invasion. They are heterodimers, with a distinct large 80-kDa catalytic, and a common small 28-kDa regulatory subunit (Capn4/CAPNS1). CAPNS1 is required to maintain stability and activity of both calpains. Despite its biological importance, the transcriptional regulation of this gene has not been studied, and the CAPNS1 promoter has not yet been characterized. In this study, we identified the main transcriptional start site, and cloned and characterized the ~2.0 kb upstream region of the CAPNS1 gene. Deletion analysis identified the core promoter located within region -187/+174. Site-directed mutagenesis, EMSA- and supershift analysis identified Sp1-, NRF-1-, and AP-1-binding elements within the CAPNS1 core promoter. Binding of NRF-1, Sp1 and AP-1 to the natural core promoter was confirmed by chromatin immunoprecipitation (ChIP). Site-directed mutagenesis at the NRF-1 site in HeLa and MCF7 cells substantially reduced core promoter activity by 70%, whereas mutation of the AP-1-binding and Sp1-binding site reduced promoter activity by 50% and 30%, respectively. Double mutation of the NRF-1 and the AP-1 site reduced promoter activity by 90%. In Drosophila SL2 cells, ectopic expression of NRF-1 led to a significant induction of CAPNS1 promoter activity. Furthermore, an siRNA against NRF-1 substantially reduced promoter activity in HeLa cells, which was paralleled by a significant downregulation of CAPNS1 mRNA. These results reveal that especially NRF-1, along with AP-1 and, to a minor extent, an Sp1 site, is essential for human CAPNS1 promoter activity and gene expression.

  4. Molecular Basis for Enhancement of the Meiotic DMCI Recombinase by RAD51AP1

    SciTech Connect

    Dray, Eloise; Dunlop, Myun Hwa; Kauppi, Liisa; San Filippo, Joseph San; Wiese, Claudia; Tsai, Miaw-Sheue; Begovic, Sead; Schild, David; Jasin, Maria; Keeney, Scott; Sung, Patrick

    2010-11-05

    Homologous recombination is needed for meiotic chromosome segregation, genome maintenance, and tumor suppression. RAD51AP1 (RAD51 Associated Protein 1) has been shown to interact with and enhance the recombinase activity of RAD51. Accordingly, genetic ablation of RAD51AP1 leads to enhanced sensitivity to and also chromosome aberrations upon DNA damage, demonstrating a role for RAD51AP1 in mitotic homologous recombination. Here we show physical association of RAD51AP1 with the meiosis-specific recombinase DMC1 and a stimulatory effect of RAD51AP1 on the DMC1-mediated D-loop reaction. Mechanistic studies have revealed that RAD51AP1 enhances the ability of the DMC1 presynaptic filament to capture the duplex DNA partner and to assemble the synaptic complex, in which the recombining DNA strands are homologously aligned. We also provide evidence that functional co-operation is dependent on complex formation between DMC1 and RAD51AP1, and that distinct epitopes in RAD51AP1 mediate interactions with RAD51 and DMC1. Finally, we show that RAD51AP1 is expressed in mouse testes, and that RAD51AP1 foci co-localize with a subset of DMC1 foci in spermatocytes. These results suggest that RAD51AP1 also serves an important role in meiotic homologous recombination.

  5. The AP-1 site is required for basal expression but is not necessary for TPA-response of the human stromelysin gene.

    PubMed Central

    Buttice, G; Quinones, S; Kurkinen, M

    1991-01-01

    We have studied the activity of the AP-1 site, a target for the Fos and Jun family of transcription factors, in the context of the human stromelysin promoter (-1303 to +4). In transiently transfected human HepG2, HeLa and fibroblast cell cultures, point-mutations in any position of the stromelysin AP-1 sequence TGAGTCA (-70 to -64) reduced both the basal level and TPA-induced expression from the stromelysin promoter. TPA-induction fold of the mutant promoters, however, was comparable to that of the wild-type promoter. Similarly, antisense c-Fos mRNA expression reduced basal activity but had no significant effect on the relative TPA-response of the stromelysin promoter. Further, in mouse F9 cells cotransfected with c-Fos and c-Jun expression plasmids, the transfected wild-type stromelysin promoter activity was increased 57-fold whereas no transactivation was detected for an AP-1 mutant stromelysin promoter. In gelshift assays, stromelysin promoter fragments (-101 to -11), containing the mutated AP-1 site, all failed to bind or compete for the in vitro synthesized Fos and Jun proteins. We interpret these data to suggest that the Fos and Jun proteins, or similar activity, and the AP-1 site are required for the basal level expression of the human stromelysin gene. Strikingly, these data also suggest that the stromelysin AP-1 site is not necessary for the TPA-response. Images PMID:1906606

  6. Apigenin inhibits PMA-induced expression of pro-inflammatory cytokines and AP-1 factors in A549 cells.

    PubMed

    Patil, Rajeshwari H; Babu, R L; Naveen Kumar, M; Kiran Kumar, K M; Hegde, Shubha M; Ramesh, Govindarajan T; Chidananda Sharma, S

    2015-05-01

    Acute and chronic alveolar or bronchial inflammation is thought to be central to the pathogenesis of many respiratory disorders. Cytokines and granulocyte macrophage colony-stimulating factors (GM-CSF) play an important role in chronic inflammation. Activator protein-1 (AP-1) the superfamily of transcription factors is involved in proliferation, differentiation, apoptosis, and transformation including inflammation. Understanding the function and regulation of proinflammatory factors involved in inflammation may provide the novel therapeutic strategies in the treatment of inflammatory diseases. Our aim of the present study is to investigate the pro-inflammatory cytokines and pattern of AP-1 factors expressed during activation of lung adenocarcinoma A549 cells by Phorbol-12-myristate-13-acetate (PMA) and to understand the anti-inflammatory effect of apigenin. A549 cells were treated with and without PMA or apigenin, and the cell viability was assessed by MTT assay. Expressions of inflammatory mediators and different AP-1 factors were analyzed by semi-quantitative RT-PCR. IL-6 protein secreted was analyzed by ELISA, and expressions of IL-1β, c-Jun, and c-Fos proteins were analyzed by Western blotting. Activation of A549 cells by PMA, induced the expression of pro-inflammatory cytokine (IL-1β, IL-2, IL-6, IL-8, and TNF-α) mRNAs and secretion of IL-6 and the expression of specific AP-1 factors (c-Jun, c-Fos, and Fra-1). Treatment of cells with apigenin, significantly inhibited PMA-stimulated mRNA expression of above pro-inflammatory cytokines, AP-1 factors, cyclooxygenase-2, and secretion of IL-6 protein. Results suggested that the AP-1 factors may be involved in inflammation and apigenin has anti-inflammatory effect, which may be useful for therapeutic management of lung inflammatory diseases.

  7. The JNK/AP-1 pathway upregulates expression of the recycling endosome rab11a gene in B cells transformed by Theileria.

    PubMed

    Lizundia, Regina; Chaussepied, Marie; Naissant, Bernina; Masse, Guillemette X; Quevillon, Emmanuel; Michel, Fréderique; Monier, Solange; Weitzman, Jonathan B; Langsley, Gordon

    2007-08-01

    Lymphocyte transformation induced by Theileria parasites involves constitutive activation of c-Jun N-terminal kinase (JNK) and the AP-1 transcription factor. We found that JNK/AP-1 activation is associated with elevated levels of Rab11 protein in Theileria-transformed B cells. We show that AP-1 regulates rab11a promoter activity in B cells and that the induction of c-Jun activity in mouse fibroblasts also leads to increased transcription of the endogenous rab11a gene, consistent with it being an AP-1 target. Pharmacological inhibition of the JNK pathway reduced Rab11 protein levels and endosome recycling of transferrin receptor (TfR) and siRNA knockdown of JNK1 and Rab11A levels also reduced TfR surface expression. We propose a model, where activation of the JNK/AP-1 pathway during cell transformation might assure that the regulation of recycling endosomes is co-ordinated with cell-cycle progression. This might be achieved via the simultaneous upregulation of the cell cycle machinery (e.g. cyclin D1) and the recycling endosome regulators (e.g. Rab11A).

  8. Physical association with WWOX suppresses c-Jun transcriptional activity.

    PubMed

    Gaudio, Eugenio; Palamarchuk, Alexey; Palumbo, Tiziana; Trapasso, Francesco; Pekarsky, Yuri; Croce, Carlo M; Aqeilan, Rami I

    2006-12-15

    WWOX is a tumor suppressor that functions as a modular protein partner of transcription factors. WWOX contains two WW domains that mediate protein-protein interactions. In this report, we show that WWOX, via its first WW domain, specifically associates with the proline-rich motif of c-Jun proto-oncogene. Our data show that phosphorylation of c-Jun caused by overexpression of mitogen-activated protein kinase kinase kinase 1 (Mekk1), an upstream activator of c-Jun, enhances the interaction of c-Jun with WWOX. Furthermore, exposure of HaCaT keratinocytes to UVC radiation resulted in the association of endogenous WWOX and c-Jun. The WWOX-c-Jun complexes mainly occur in the cytoplasm. Expression of WWOX attenuates the ability of MEKK1 to increase the activity of a c-Jun-driven activating protein-1 (AP-1)-luciferase reporter plasmid. In contrast, a point mutation in the first WW domain of WWOX has no effect on transactivation of AP-1 when coexpressed with c-Jun protein. Our findings reveal a novel functional cross-talk between c-Jun transcription factor and WWOX tumor suppressor protein.

  9. Assessment of costimulation and coinhibition in a triple parameter T cell reporter line: Simultaneous measurement of NF-κB, NFAT and AP-1.

    PubMed

    Jutz, Sabrina; Leitner, Judith; Schmetterer, Klaus; Doel-Perez, Iago; Majdic, Otto; Grabmeier-Pfistershammer, Katharina; Paster, Wolfgang; Huppa, Johannes B; Steinberger, Peter

    2016-03-01

    Engagement of the T cell receptor complex reprograms T cells for proliferation, cytokine production and differentiation towards effector cells. This process depends on activating costimulatory signals and is counteracted by coinhibitory molecules. Three transcription factors, namely NF-κB, NFAT and AP-1, have a major role in inducing the transcriptional program that is required for T cell activation and differentiation. Here we describe the generation of a triple parameter reporter based on the human Jurkat T cell line, where response elements for NF-κB, NFAT and AP-1 drive the expression of the fluorescent proteins CFP, eGFP and mCherry, respectively. The emission spectra of these proteins allow simultaneous assessment of NF-κB, NFAT and AP-1 activity in response to stimulation. Ligation of the TCR complex induced moderate reporter activity, which was strongly enhanced upon coengagement of the costimulatory receptors CD2 or CD28. Moreover, we have generated and tested triple parameter reporter cells that harbor costimulatory and inhibitory receptors not endogenously expressed in the Jurkat cells. In these experiments we could show that engagement of the costimulatory molecule 4-1BB enhances NF-κB and AP-1 activity, whereas coinhibition via PD-1 or BTLA strongly reduced the activation of NF-κB and NFAT. Engagement of BTLA significantly inhibited AP-1, whereas PD-1 had little effect on the activation of this transcription factor. Our triple parameter reporter T cell line is an excellent tool to assess the effect of costimulatory and coinhibitory receptors on NF-κB, NFAT and AP-1 activity and has a wide range of applications beyond the evaluation of costimulatory pathways.

  10. High glucose-induced, endothelin-dependent fibronectin synthesis is mediated via NF-kappa B and AP-1.

    PubMed

    Chen, Shali; Mukherjee, Suranjana; Chakraborty, Chandan; Chakrabarti, Subrata

    2003-02-01

    Human endothelial cells cultured under high glucose (HG) conditions were shown before to upregulate several basement membrane proteins, including fibronectin (FN), thus mimicking effects of diabetes. Using human macrovascular (HUVEC) and microvascular (HMEC) endothelial cell lines, we evaluated in the present study some of the key molecular signaling events involved in HG-induced FN overexpression. This expression was shown to be dependent on endogenous endothelin (ET) receptor-mediated signaling. We also examined the roles played by protein kinase C (PKC) and the transcription factors nuclear factor kappaB (NF-kappaB) and activating protein (AP)-1 with respect to such changes. HG, PKC activators, and ETs (ET-1 and ET-3) that increased FN expression also caused activation of NF-kappaB and AP-1. Inhibitors of both NF-kappaB and AP-1 prevented HG- and ET-induced FN production. ET receptor blockade also prevented these HG- and ET-mediated changes. The results of this study indicate that glucose-induced increased FN production in diabetes may be mediated via ET-dependent NF-kappaB and AP-1 activation.

  11. Structural basis of transcription activation.

    PubMed

    Feng, Yu; Zhang, Yu; Ebright, Richard H

    2016-06-10

    Class II transcription activators function by binding to a DNA site overlapping a core promoter and stimulating isomerization of an initial RNA polymerase (RNAP)-promoter closed complex into a catalytically competent RNAP-promoter open complex. Here, we report a 4.4 angstrom crystal structure of an intact bacterial class II transcription activation complex. The structure comprises Thermus thermophilus transcription activator protein TTHB099 (TAP) [homolog of Escherichia coli catabolite activator protein (CAP)], T. thermophilus RNAP σ(A) holoenzyme, a class II TAP-dependent promoter, and a ribotetranucleotide primer. The structure reveals the interactions between RNAP holoenzyme and DNA responsible for transcription initiation and reveals the interactions between TAP and RNAP holoenzyme responsible for transcription activation. The structure indicates that TAP stimulates isomerization through simple, adhesive, stabilizing protein-protein interactions with RNAP holoenzyme. Copyright © 2016, American Association for the Advancement of Science.

  12. Quercetin modulates NF-kappa B and AP-1/JNK pathways to induce cell death in human hepatoma cells.

    PubMed

    Granado-Serrano, Ana Belén; Martín, María Angeles; Bravo, Laura; Goya, Luis; Ramos, Sonia

    2010-01-01

    Quercetin, a dietary flavonoid, has been shown to possess anticarcinogenic properties, but the precise molecular mechanisms of action are not thoroughly elucidated. The aim of this study was to investigate the regulatory effect of quercetin (50 microM) on two main transcription factors (NF-kappa B and AP-1) related to survival/proliferation pathways in a human hepatoma cell line (HepG2) over time. Quercetin induced a significant time-dependent inactivation of the NF-kappa B pathway consistent with a downregulation of the NF-kappa B binding activity (from 15 min onward). These features were in concert with a time-dependent activation (starting at 15 min and maintained up to 18 h) of the AP-1/JNK pathway, which played an important role in the control of the cell death induced by the flavonoid and contributed to the regulation of survival/proliferation (AKT, ERK) and death (caspase-3, p38, unbalance of Bcl-2 proapoptotic and antiapoptotic proteins) signals. These data suggest that NF-kappa B and AP-1 play a main role in the tight regulation of survival/proliferation pathways exerted by quercetin and that the sustained JNK/AP-1 activation and inhibition of NF-kappa B provoked by the flavonoid induced HepG2 death.

  13. Helicobacter pylori promotes invasion and metastasis of gastric cancer cells through activation of AP-1 and up-regulation of CACUL1.

    PubMed

    Kong, Ying; Ma, Li-qing; Bai, Pei-song; Da, Rong; Sun, Hong; Qi, Xiao-gai; Ma, Jie-qun; Zhao, Ru-ming; Chen, Nan-zheng; Nan, Ke-jun

    2013-11-01

    Infection with Helicobacter pylori is important in the development and progression of gastric cancer. However, the mechanisms that regulate this activation in gastric tumors remain elusive. CACUL1 has been cloned and identified as a novel gene that is expressed in many types of cancer and is involved in cell cycle regulation and tumor growth. The current study aimed to examine the expression of CACUL1 in gastric cancer samples and analyze its correlation with H. pylori infection. We found that CACUL1 was highly expressed in gastric cancer tissues and negatively correlated with gastric cancer differentiation and TNM stage. In addition, CACUL1 expression was high in H. pylori-infected tissues compared with H. pylori non-infected tissue. We found that H. pylori could up-regulate CACUL1 expression through activating protein 1. The up-regulation of CACUL1 expression could promote matrix metalloproteinase 9 and Slug expression to increase invasion and metastasis of tumor cells. These results suggested that H. pylori-triggered CACUL1 production occurred in an activating protein 1-dependent manner and regulated matrix metalloproteinase 9 and Slug expression to affect the invasion and metastasis of tumor cells. Therefore, CACUL1 is a potential therapeutic target for the treatment of aggressive gastric cancer.

  14. An AP1 binding site upstream of the kappa immunoglobulin intron enhancer binds inducible factors and contributes to expression.

    PubMed Central

    Schanke, J T; Marcuzzi, A; Podzorski, R P; Van Ness, B

    1994-01-01

    Expression of the kappa immunoglobulin light chain gene requires developmental- and tissue-specific regulation by trans-acting factors which interact with two distinct enhancer elements. A new protein-DNA interaction has been identified upstream of the intron enhancer, within the matrix-associated region of the J-C intron. The binding activity is greatly inducible in pre-B cells by bacterial lipopolysaccharide and interleukin-1 but specific complexes are found at all stages of B cell development tested. The footprinted binding site is homologous to the consensus AP1 motif. The protein components of this complex are specifically competed by an AP1 consensus motif and were shown by supershift to include c-Jun and c-Fos, suggesting that this binding site is an AP1 motif and that the Jun and Fos families of transcription factors play a role in the regulation of the kappa light chain gene. Mutation of the AP1 motif in the context of the intron enhancer was shown to decrease enhancer-mediated activation of the promoter in both pre-B cells induced with LPS and constitutive expression in mature B cells. Images PMID:7816634

  15. The inflammation-related gene S100A12 is positively regulated by C/EBPβ and AP-1 in pigs.

    PubMed

    Li, Xinyun; Tang, Juan; Xu, Jing; Zhu, Mengjin; Cao, Jianhua; Liu, Ying; Yu, Mei; Zhao, Shuhong

    2014-08-08

    S100A12 is involved in the inflammatory response and is considered an important marker for many inflammatory diseases in humans. Our previous studies indicated that the S100A12 gene was abundant in the immune tissues of pigs and was significantly upregulated during infection with Haemophilus parasuis (HPS) or porcine circovirus type 2 (PCV2). In this study, the mechanism of transcriptional regulation of S100A12 was investigated in pigs. Our results showed that S100A12, CCAAT/enhancer-binding protein beta (C/EBPβ) and activator protein-1 (AP-1) genes were up-regulated in PK-15 (ATCC, CCL-33) cells when treated with LPS or Poly I: C. Additionally, the promoter activity and expression level of the S100A12 gene were significantly upregulated when C/EBPβ or AP-1 were overexpressed. We utilized electromobility shift assays (EMSA) to confirm that C/EBPβ and AP-1 could directly bind the S100A12 gene promoter. We also found that the transcriptional activity and expression levels of C/EBPβ and AP-1 could positively regulate each other. Furthermore, the promoter activity of the S100A12 gene was higher when C/EBPβ and AP-1 were cotransfected than when they were transfected individually. We concluded that the S100A12 gene was cooperatively and positively regulated by C/EBPβ and AP-1 in pigs. Our study offers new insight into the transcriptional regulation of the S100A12 gene.

  16. Thymus vulgaris alleviates UVB irradiation induced skin damage via inhibition of MAPK/AP-1 and activation of Nrf2-ARE antioxidant system.

    PubMed

    Sun, Zhengwang; Park, Sang Yong; Hwang, Eunson; Zhang, Mengyang; Seo, Seul A; Lin, Pei; Yi, Tae-Hoo

    2017-02-01

    Solar ultraviolet (UV) radiation-induced reactive oxidative species is mainly responsible for the development of photoageing. Rosmarinic acid was one of the main bioactive components detected in Thymus vulgaris (TV) we extracted. In this study, UVB-induced skin damages have been shown to be ameliorated by treatment with TV in hairless mice (HR-1) skin, demonstrated by decreased matrix metalloproteinases (MMPs) and increased collagen production. However, the underlying molecular mechanism on which TV acted was unclear. We examined the photoprotective effects of TV against UVB and elucidated the molecular mechanism in normal human dermal fibroblasts. Thymus vulgaris remarkably prevented the UVB-induced reactive oxygen species and lactate dehydrogenase. Dose-dependent increase in glutathione, NAD(P)H: quinone oxidoreductase1 and heme oxygenase-1, by TV was confirmed by increased nuclear accumulation of Nrf2. Furthermore, 5-Methoxyindole-2-carboxylic acid was introduced as a specific inhibitor of dihydrolipoyl dehydrogenase (DLD). We demonstrated that Nrf2 expression was regulated by DLD, which was a tricarboxylic acid cycle-associated protein that decreased after UVB exposure. Besides, TV significantly diminished UVB induced phosphorylation of mitogen activated protein kinases pathway, containing extracellular signal-regulated kinase, Jun N-terminal kinase and p38, which consequently reduced phosphorylated c-fos and c-jun. Our results suggest that TV is a potential botanical agent for use against UV radiation-induced oxidative stress mediated skin damages. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  17. Identification of cyanidin glycosides as constituents of freeze-dried black raspberries which inhibit anti-benzo[a]pyrene-7,8-diol-9,10-epoxide induced NFκB and AP-1 activity

    PubMed Central

    Hecht, Stephen S.; Huang, Chuanshu; Stoner, Gary D.; Li, Jingxia; Kenney, Patrick M. J.; Sturla, Shana J.; Carmella, Steven G.

    2010-01-01

    Dietary freeze-dried black raspberries inhibit tumor induction by N-nitrosomethylbenzylamine in the rat esophagus, but the constituents responsible for this chemopreventive activity have not been identified. We fractionated freeze-dried black raspberries and used mouse epidermal JB6 Cl 41 cells stably transfected with either a nuclear factor kappa B (NFκB)- or an activator protein 1 (AP-1)-luciferase reporter, and treated with racemic anti-benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE), to assess the inhibitory effects of the fractions. The ethanol and water extracts of the freeze-dried black raspberries had inhibitory activity and these extracts were fractionated by HPLC to give several bioactive fractions. Further HPLC analysis yielded multiple subfractions, some of which inhibited BPDE-induced NFκB activity. Major constituents of the most active subfractions were identified by their spectral properties and in comparison with standards as cyanidin-3-O-glucoside, cyanidin 3-O-(2G-xylosylrutinoside) and cyanidin 3-O-rutinoside. Analysis of freeze-dried black raspberries indicated that these three components comprised ∼3.4% of the material by dry weight. Consistent with these results, standard cyanidin-3-O-glucoside and cyanidin chloride were also good inhibitors of BPDE-induced NFκB activity. The results of this study demonstrate that cyanidin glycosides of freeze-dried black raspberries are bioactive compounds which could account for at least some of the chemopreventive activity observed in animal models. PMID:16522666

  18. Induction of the mammalian stress response gene GADD153 by oxidative stress: role of AP-1 element.

    PubMed Central

    Guyton, K Z; Xu, Q; Holbrook, N J

    1996-01-01

    GADD153 is a CCAAT/enhancer-binding-protein-related gene that may function to control cellular growth in response to stress signals. In this study, a variety of oxidant treatments were shown to stimulate endogenous GADD153 mRNA expression and to transcriptionally activate a GADD153 promoter-reporter gene construct in transfected HeLa cells. Both commonalities and distinctions in the induction of GADD153 by H2O2 and the thiol-reactive compound arsenite were demonstrated. GADD153 mRNA induction by both H2O2 and arsenite was potentiated by GSH depletion, and completely inhibited by N-acetyl-cysteine. o-Phenanthroline and mannitol blocked GADD153 induction by H2O2, indicating that iron-generated hydroxyl radical mediates this induction. Concordantly, GSH peroxidase overexpression in WI38 cells attenuated GADD153 mRNA induction by H2O2. However, GADD153 induction by arsenite was only modestly reduced in the same cells, suggesting a lesser contribution of peroxides to gene activation by arsenite. We also demonstrated that oxidative stress participates in the induction of GADD153 by UVC (254 nm) irradiation. Finally, both promoter-deletion analysis and point mutation of the AP-1 site in an otherwise intact promoter support a significant role for AP-1 in transcriptional activation of GADD153 by UVC or oxidant treatment. Indeed, exposure of cells to oxidants or UVC stimulated binding of Fos and Jun to the GADD153 AP-1 element. Together, these results demonstrate that both free-radical generation and thiol modification can transcriptionally activate GADD153, and that AP-1 is critical to oxidative regulation of this gene. This study further supports a role for the GADD153 gene product in the cellular response to oxidant injury. PMID:8670069

  19. Resveratrol regulates gene transcription via activation of stimulus-responsive transcription factors.

    PubMed

    Thiel, Gerald; Rössler, Oliver G

    2017-03-01

    Resveratrol (trans-3,4',5-trihydroxystilbene), a polyphenolic phytoalexin of grapes and other fruits and plants, is a common constituent of our diet and of dietary supplements. Many health-promoting benefits have been connected with resveratrol in the treatment of cardiovascular diseases, cancer, diabetes, inflammation, neurodegeneration, and diseases connected with aging. To explain the pleiotropic effects of resveratrol, the molecular targets of this compound have to be identified on the cellular level. Resveratrol induces intracellular signal transduction pathways which ultimately lead to changes in the gene expression pattern of the cells. Here, we review the effect of resveratrol on the activation of the stimulus-responsive transcription factors CREB, AP-1, Egr-1, Elk-1, and Nrf2. Following activation, these transcription factors induce transcription of delayed response genes. The gene products of these delayed response genes are ultimately responsible for the changes in the biochemistry and physiology of resveratrol-treated cells. The activation of stimulus-responsive transcription factors may explain many of the intracellular activities of resveratrol. However, results obtained in vitro may not easily be transferred to in vivo systems.

  20. Study on JNK/AP-1 signaling pathway of airway mucus hypersecretion of severe pneumonia under RSV infection.

    PubMed

    Li, X-M; Sun, S-Z; Wu, F-L; Shi, T; Fan, H-J; Li, D-Z

    2016-03-01

    To investigate the JNK/AP-1 signaling pathway of airway mucus hypersecretion of severe pneumonia under respiratory virus (RSV) infection. Total of 56 severe pneumonia children under RSV infection were selected. Reverse transcription polymerase chain reaction (RT-PCR) was performed to measure the expression quantity of MUC5B mRNA and MUC5AC mRNA, and ELISA was used to measure the expression quantity of MUC5AC and MUC5B proteins. Following that, the children were divided into airway mucus hypersecretion group (n = 37) and non-hypersecretion group (n = 19). Western blotting was performed to detect the expression levels of JNK1/2, p-JNK1/2 and AP-1 proteins. Expression of MUC5AC and MUC5B proteins, and MUC5AC mRNA and MUC5B mRNA in the airway mucus hypersecretion group were significantly higher than those in the non-hypersecretion group (p < 0.05). The expression levels of JNK1/2, p-JNK1/2 and AP-1 proteins in airway mucus hypersecretion group were higher than those in the non-hypersecretion group (p < 0.05). MUC5AC and MUC5B can be used as marker molecules of airway mucus hypersecretion. Airway mucus hypersecretion of severe pneumonia induced by RSV might be related to the activation of JNK/AP-1 signaling pathway.

  1. Peptidoglycan induces interleukin-6 expression through the TLR2 receptor, JNK, c-Jun, and AP-1 pathways in microglia.

    PubMed

    Lin, Hsiao-Yun; Tang, Chih-Hsin; Chen, Jia-Hong; Chuang, Jing-Yuan; Huang, Ssu-Ming; Tan, Tzu-Wei; Lai, Chih-Ho; Lu, Dah-Yuu

    2011-06-01

    We recently reported that peptidoglycan (PGN), a cell wall component of the Gram-positive bacterium, induces NF-κB activation and microglia activation. However, PGN-regulated AP-1 activation and cytokine expression in microglia remains unclear. This study investigated how PGN influences the signaling pathway involved in IL-6 production in microglia. IL-6 mRNA and protein level up-regulation were increased by PGN in a concentration- and time-dependent manner. In addition, PGN increased toll-like receptor-2 (TLR2) expression, but not TLR4 receptor up-regulation. Administration of TLR2 siRNA or TLR2 neutralized antibody effectively inhibited PGN-induced IL-6 expression. In contrast, PGN-induced IL-6 mRNA and protein up-regulation were attenuated by the SAPK/JNK (c-Jun N-terminal kinases) inhibitor SP600125. Treatment of microglia with PGN increased levels of JNK phosphorylation and c-Jun phosphorylation, and up-regulated of JNK kinase activity. Treatment of microglia with AP-1 inhibitors (Tanshinone IIA and curcumin) effectively reduced PGN-induced IL-6 expression. PGN also significantly increased c-Fos and phospho-c-Jun translocation to nucleus. In line with this, PGN also increased AP-1-DNA complexes formation, as determined by the electrophoretic mobility shift assay. Furthermore, PGN also increased IL-6 transcription activity determined by transfection with IL-6 promoter construct plasmid. Co-transfection with dominant negative mutant of JNK (DN-JNK), or treatment with SP600125, curcumin, or Tanshinone IIA effectively antagonized PGN-increased IL-6 transcription activity. Our data demonstrate that PGN-induced IL-6 expression is mediated by AP-1 activation through the TLR2 and JNK/c-Jun pathways in microglia.

  2. Activation of gene transcription via CIM0216, a synthetic ligand of transient receptor potential melastatin-3 (TRPM3) channels.

    PubMed

    Rubil, Sandra; Thiel, Gerald

    2017-01-02

    Several compounds have been proposed to stimulate TRPM3 Ca(2+) channels. We recently showed that stimulation of TRPM3 channels with pregnenolone sulfate activated the transcription factor AP-1, while other proposed TRPM3 ligands (nifedipine, D-erythro-sphingosine) exhibited either no or TRPM3-independent effects on gene transcription. Here, we have analyzed the transcriptional activity of CIM0216, a synthetic TRPM3 ligand proposed to have a higher potency and affinity for TRPM3 than pregnenolone sulfate. The results show that CIM0216 treatment of HEK293 cells expressing TRPM3 channels activated AP-1 and stimulated the transcriptional activation potential of c-Jun and c-Fos, 2 basic region leucine zipper transcription factors that constitute AP-1. CIM0216-induced gene transcription was attenuated by knock-down of TRPM3 or treatment with mefenamic acid, a TRPM3 inhibitor. CIM0216 was similarly or less capable in activating TRPM3-mediated gene transcription, suggesting that pregnenolone sulfate is still the ligand of choice for changing the gene expression pattern via TRPM3.

  3. Foxl2, a Forkhead Transcription Factor, Modulates Nonclassical Activity of the Estrogen Receptor-α

    PubMed Central

    Kim, So-Youn; Weiss, Jeffrey; Tong, Minghan; Laronda, Monica M.; Lee, Eun-Jig; Jameson, J. Larry

    2009-01-01

    Foxl2 is a forkhead transcription factor required for ovary development and ovarian follicle maturation. In this report, we identified and characterized a functional relationship between Foxl2 expression and estrogen receptor (ER)-α signaling. We show that Foxl2 has no effect on classical ERα-mediated transcription, which occurs through canonical estrogen response elements. However, Foxl2 suppresses ERα signaling through nonclassical tethered transcriptional pathways. Specifically, the selective ER modulator tamoxifen stimulates activator protein-1 (AP1)-dependent transcription via the ERα, and this enhancement is blocked by Foxl2. Two lines of evidence suggest that Foxl2 suppression is mediated by physical interactions with ERα rather than direct action at AP1 binding sites. First, ERα is coimmunoprecipitated with Foxl2. Second, activation of a upstream activating sequence (UAS) reporter by Gal4-cJun in the presence of ERα and tamoxifen was blocked by Foxl2, demonstrating suppression in the absence of an AP1 site. Cyclooxygenase-2 (COX2), which is required for ovulation, was identified through expression profiling as a candidate physiological target for nonclassical ERα signaling and thus modulation by ERα/Foxl2 interactions. This possibility was confirmed by two sets of experiments. COX2 protein levels were induced by ERα in the presence of tamoxifen, and protein expression was suppressed by Foxl2. In addition, ERα stimulation of the COX2 promoter was repressed by Foxl2. We conclude that ERα and Foxl2 interact and that Foxl2 selectively suppresses ERα-mediated transcription of AP1-regulated genes. These data provide a potential point of convergence for ERα and Foxl2 to regulate ovarian development and function. PMID:19797124

  4. Thermodynamic Characterization of the Folding Coupled DNA Binding by the Monomeric Transcription Activator GCN4 Peptide

    PubMed Central

    Wang, Xu; Cao, Wei; Cao, Aoneng; Lai, Luhua

    2003-01-01

    Dimerization is a widely believed critical requirement for the yeast transcriptional activator GCN4 specifically recognizing its DNA target sites. Nonetheless, the binding of the monomeric GCN4 to DNA target sites AP-1 and ATF/CREB was recently detected by kinetic studies. Here, for the first time, we present a detailed description of the thermodynamics of a monomeric peptide GCN4-br, the basic region (226–252) of GCN4, binding to AP-1, and ATF/CREB. GCN4 specifically binds to AP-1 and ATF/CREB in the monomeric form as shown by our circular dichroism thermal unfolding measurements. Isothermal titration calorimetry experiments indicate that the binding process of GCN4-br with DNA is enthalpically driven, accompanied by an unfavorable entropy change. The temperature dependence of ΔH0 reveals negative changes in heat capacity ΔCp: ΔCp = −0.92 kJ · mol−1 K−1 and ΔCp = −0.95 kJ · mol−1 K−1 for GCN4-br binding to AP-1 and ATF/CREB, respectively, which is a striking manifestation of GCN4-br specifically recognizing DNA target sites. These thermodynamic characteristics may give new insight into the mechanism by which GCN4 protein binds to DNA target sites for its transcriptional regulation. PMID:12609888

  5. Overt expression of AP-1 reduces alpha myosin heavy chain expression and contributes to heart failure from chronic volume overload.

    PubMed

    Freire, Grace; Ocampo, Catherina; Ilbawi, Nadim; Griffin, Andrew J; Gupta, Madhu

    2007-10-01

    Reduced expression of alpha-MHC plays a significant role in cardiac contractile dysfunction from hemodynamic overload. Previously, Pur proteins and YY1 have been shown to play a role in alpha-MHC repression during heart failure induced by pressure overload and by spontaneous hypertension, respectively. This was not observed in volume-overload-induced heart failure, suggesting additional regulatory mechanisms for alpha-MHC repression. The present study was performed to identify volume overload responsive transcription factors involved in alpha-MHC gene regulation. DNA binding activity of several transcription factors was evaluated in a functionally characterized rat model of heart failure induced by aorto-caval shunt. After 10 weeks of shunt, severe LV dilatation and reduced LV function were accompanied by increased expression of ANF and beta-MHC, and decreased expression of alpha-MHC. This was associated with dramatic (10-fold) activation of AP-1 together with increased expression of c-fos and c-jun. AP-1 activation was not observed following 4 weeks of shunt when cardiac function was preserved. In cultured cardiomyocytes, induction of AP-1 by PMA attenuated alpha-MHC mRNA by 60%. Transient transfection assays mapped PMA responsive sequence to -582 to -588 bp of alpha-MHC promoter. Deletion or mutation of these nucleotides had minimal effect on basal promoter activity but played a dominant role in PMA-mediated repression of alpha-MHC promoter activity. Over-expression of c-fos and c-jun in cardiomyocytes inhibited alpha-MHC promoter activity in a concentration dependent manner. Data suggest a repressive role of AP-1 in alpha-MHC expression and its possible involvement in the transition from compensatory hypertrophy to heart failure in chronic volume overload.

  6. On involvement of transcription factors nuclear factor kappa-light-chain-enhancer of activated B cells, activator protein-1 and signal transducer and activator of transcription-3 in photodynamic therapy-induced death of crayfish neurons and satellite glial cells

    NASA Astrophysics Data System (ADS)

    Berezhnaya, Elena; Neginskaya, Marya; Kovaleva, Vera; Sharifulina, Svetlana; Ischenko, Irina; Komandirov, Maxim; Rudkovskii, Mikhail; Uzdensky, Anatoly B.

    2015-07-01

    Photodynamic therapy (PDT) is currently used in the treatment of brain tumors. However, not only malignant cells but also neighboring normal neurons and glial cells are damaged during PDT. In order to study the potential role of transcription factors-nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), activator protein (AP-1), and signal transducer and activator of transcription-3 (STAT-3)-in photodynamic injury of normal neurons and glia, we photosensitized the isolated crayfish mechanoreceptor consisting of a single sensory neuron enveloped by glial cells. Application of different inhibitors and activators showed that transcription factors NF-κB (inhibitors caffeic acid phenethyl ester and parthenolide, activator betulinic acid), AP-1 (inhibitor SR11302), and STAT-3 (inhibitors stattic and cucurbitacine) influenced PDT-induced death and survival of neurons and glial cells in different ways. These experiments indicated involvement of NF-κB in PDT-induced necrosis of neurons and apoptosis of glial cells. However, in glial cells, it played the antinecrotic role. AP-1 was not involved in PDT-induced necrosis of neurons and glia, but mediated glial apoptosis. STAT-3 was involved in PDT-induced apoptosis of glial cells and necrosis of neurons and glia. Therefore, signaling pathways that regulate cell death and survival in neurons and glial cells are different. Using various inhibitors or activators of transcription factors, one can differently influence the sensitivity and resistance of neurons and glial cells to PDT.

  7. Integrative genomics identifies YY1AP1 as an oncogenic driver in EpCAM(+) AFP(+) hepatocellular carcinoma.

    PubMed

    Zhao, X; Parpart, S; Takai, A; Roessler, S; Budhu, A; Yu, Z; Blank, M; Zhang, Y E; Jia, H-L; Ye, Q-H; Qin, L-X; Tang, Z-Y; Thorgeirsson, S S; Wang, X W

    2015-09-24

    Identification of key drivers and new therapeutic targets is important given the poor prognosis for hepatocellular carcinoma (HCC) patients, particularly those ineligible for surgical resection or liver transplant. However, the approach to identify such driver genes is facing significant challenges due to the genomically heterogenous nature of HCC. Here we tested whether the integrative genomic profiling of a well-defined HCC subset that is classified by an extreme EpCAM(+) AFP(+) gene expression signature and associated with poor prognosis, all attributes of a stem cell-like phenotype, could uncover survival-related driver genes in HCC. Following transcriptomic analysis of the well-defined HCC cases, a Gene Set Enrichment Analysis coupled with genomic copy number alteration assessment revealed that YY1-associated protein 1 (YY1AP1) is a critical oncoprotein specifically activated in EpCAM(+) AFP(+) HCC. YY1AP1 silencing eliminates oncogene addiction by altering the chromatin landscape and triggering massive apoptosis in vitro and tumor suppression in vivo. YY1AP1 expression promotes HCC proliferation and is required for the maintenance of stem cell features. We revealed that YY1AP1 cooperates with YY1 to alter the chromatin landscape and activate transcription of stemness regulators. Thus YY1AP1 may serve as a key molecular target for EpCAM(+) AFP(+) HCC subtype. Our results demonstrate the feasibility and power of a new strategy by utilizing well-defined patient samples and integrative genomics to uncover critical pathways linked to HCC subtypes with prognostic impact.

  8. Signalling in inflammatory skin disease by AP-1 (Fos/Jun).

    PubMed

    Uluçkan, Özge; Guinea-Viniegra, Juan; Jimenez, Maria; Wagner, Erwin F

    2015-01-01

    Skin inflammation is a physiological reaction to tissue injury, pathogen invasion and irritants. During this process, innate and/or adaptive immune cells are activated and recruited to the site of inflammation to either promote or suppress inflammation. The sequential recruitment and activation of immune cells is modulated by a combination of cytokines and chemokines, which are regulated by transcription factors, such as AP-1 (Fos/Jun), NF-κB, NFATs, and STATs. Here we review the present evidence and the underlying mechanisms of how Jun/AP-1 proteins control skin inflammation. Genetically engineered mouse models (GEMMs) in which AP-1 proteins are deleted in the epidermis have revealed that these proteins control cytokine expression at multiple levels. Constitutive epidermal deletion of JunB in mice leads to a multi-organ disease characterised by increased levels of pro-inflammatory cytokines. These JunB-deficient mutant mice display several phenotypes from skin inflammation to a G-CSF-dependent myeloproliferative disease, as well as kidney atrophy and bone loss, reminiscent of psoriasis and systemic lupus erythematosus. Importantly, epidermal deletion of both JunB and c-Jun in an inducible manner in adult mice leads to a psoriasis-like disease, in which the epidermal proteome expression profile is comparable to the one from psoriasis patient samples. In this GEMM and in psoriasis patient-derived material, S100A8/A9-dependent C3/CFB complement activation, as well as a miR-21-dependent TIMP-3/TACE pathway leading to TNF-α shedding, plays causal roles in disease development. The newly identified therapeutic targets from GEMMs together with investigations in human patient samples open up new avenues for therapeutic interventions for psoriasis and related inflammatory skin diseases.

  9. Rapid phosphorylation of Elk-1 transcription factor and activation of MAP kinase signal transduction pathways in response to visual stimulation.

    PubMed

    Kaminska, B; Kaczmarek, L; Zangenehpour, S; Chaudhuri, A

    1999-06-01

    The AP-1 transcription factor, which is composed of various combinations of Fos and Jun proteins, is believed to be a key participant in molecular processes that guide activity-dependent changes in gene expression. In this study, we investigated the activity of different MAP kinases that have been implicated in AP-1 activation. We examined the activities of ERK, JNK/SAPK, and p38 MAPK along with their nuclear targets (Elk-1 and c-Jun) in rat visual cortex after light stimulation. The transcription factor Elk-1 (a possible regulator of c-fos expression) was found to be transiently modified by phosphorylation when visual stimulation was applied after a period of dark rearing. In vitro kinase assay with Elk-1 as substrate showed that light stimulation activated MAPK/ERK in visual cortex but not frontal cortex. Furthermore, ERK activation was temporally matched to onset of Elk-1 phosphorylation. The activity of JNK1 (c-Jun N-terminal kinase 1) was elevated at 2-6 h after visual exposure and was also temporally correlated to increase of endogenous P-c-Jun levels and its appearance within the AP-1 DNA-binding complex. The activities of p38 MAP kinases did not change significantly. These results demonstrate the differential engagement of MAPK signaling pathways following sensory stimulation and their relative effects upon AP-1 expression in the intact brain. Copyright 1999 Academic Press.

  10. Interactions between SIRT1 and AP-1 reveal a mechanistic insight into the growth promoting properties of alumina (Al2O3) nanoparticles in mouse skin epithelial cells.

    PubMed

    Dey, Swatee; Bakthavatchalu, Vasudevan; Tseng, Michael T; Wu, Peng; Florence, Rebecca L; Grulke, Eric A; Yokel, Robert A; Dhar, Sanjit Kumar; Yang, Hsin-Sheng; Chen, Yumin; St Clair, Daret K

    2008-10-01

    The physicochemical properties of nanomaterials differ from those of the bulk material of the same composition. However, little is known about the underlying effects of these particles in carcinogenesis. The purpose of this study was to determine the mechanisms involved in the carcinogenic properties of nanoparticles using aluminum oxide (Al(2)O(3)/alumina) nanoparticles as the prototype. Well-established mouse epithelial JB6 cells, sensitive to neoplastic transformation, were used as the experimental model. We demonstrate that alumina was internalized and maintained its physicochemical composition inside the cells. Alumina increased cell proliferation (53%), proliferating cell nuclear antigen (PCNA) levels, cell viability and growth in soft agar. The level of manganese superoxide dismutase, a key mitochondrial antioxidant enzyme, was elevated, suggesting a redox signaling event. In addition, the levels of reactive oxygen species and the activities of the redox sensitive transcription factor activator protein-1 (AP-1) and a longevity-related protein, sirtuin 1 (SIRT1), were increased. SIRT1 knockdown reduces DNA synthesis, cell viability, PCNA levels, AP-1 transcriptional activity and protein levels of its targets, JunD, c-Jun and BcL-xl, more than controls do. Immunoprecipitation studies revealed that SIRT1 interacts with the AP-1 components c-Jun and JunD but not with c-Fos. The results identify SIRT1 as an AP-1 modulator and suggest a novel mechanism by which alumina nanoparticles may function as a potential carcinogen.

  11. AP-1-Targeted Inhibition of Macrophage Function and Lipopolysaccharide/D-Galactosamine-Induced Hepatitis by Phyllanthus acidus Methanolic Extract.

    PubMed

    Hossen, Muhammad Jahangir; Kim, Mi-Yeon; Kim, Jong-Hoon; Cho, Jae Youl

    2015-01-01

    Traditionally, Phyllanthus acidus (Phyllanthaceae) has been used for the treatment of rheumatism, bronchitis, asthma, respiratory disorders, and hepatitis. Recently, we showed that a methanol extract of Phyllanthaceae (Pa-ME) has a potent anti-inflammatory activity in RAW264.7 cells and strongly ameliorates HCl / EtOH -induced gastric ulcers in mice by targeting the Src/Syk of NF-κB. In the present study, we explored the molecular mechanism of Pa-ME on the AP-1 activation pathway and evaluated its potential hepatoprotective effects. To do this, we employed lipopolysaccharide (LPS)-stimulated RAW264.7 cells and U937 cells and an LPS/D-galactosamine (D- GaIN )-induced acute hepatitis mouse model. We utilized a multitude of assays, including immunoblotting analysis, reporter gene assays, and mRNA expression analysis, to determine the effect of Pa-ME on the AP-1 pathway. Pa-ME strikingly suppressed the production of LPS-induced pro-inflammatory cytokines including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α). Furthermore, Pa-ME also strongly inhibited activator protein-1 (AP-1) activation and mitogen-activated protein kinase (MAPK) phosphorylation in LPS-stimulated RAW264.7 macrophages cells and the U937 monocyte like human cell line. Moreover, pre-treatment with Pa-ME exhibited strong hepatoprotective and curative effects in an LPS/D-Gal-induced mouse hepatitis model as evidenced by a decrease in elevated serum AST and ALT levels and the amelioration of histological damage. Taken together, our data suggest that Pa-ME might play a crucial ethnopharmacological role as a hepatoprotective herbal remedy by suppressing MAPK signaling and the activity of the downstream transcription factor AP-1.

  12. Sry is a transcriptional activator.

    PubMed

    Dubin, R A; Ostrer, H

    1994-09-01

    The SRY gene functions as a genetic switch in gonadal ridge initiating testis determination. The mouse Sry and human SRY open reading frames (ORFs) share a conserved DNA-binding domain (the HMG-box) yet exhibit no additional homology outside this region. As judged by the accumulation of lacZ-SRY hybrid proteins in the nucleus, both the human and mouse SRY ORFs contain a nuclear localization signal. The mouse Sry HMG-box domain selectively binds the sequence NACAAT in vitro when challenged with a random pool of oligonucleotides and binds AACAAT with the highest affinity. When put under the control of a heterologous promotor, the mouse Sry gene activated transcription of a reporter gene containing multiple copies of the AACAAT binding site. Activation was likewise observed for a GAL4-responsive reporter gene, when the mouse Sry gene was linked to the DNA-binding domain of GAL4. Using this system, the activation function was mapped to a glutamine/histidine-rich domain. In addition, LexA-mouse Sry fusion genes activated a LexA-responsive reporter gene in yeast. In contrast, a GAL4-human SRY fusion gene did not cause transcriptional activation. These studies suggest that both the human and the mouse SRY ORFs encode nuclear, DNA-binding proteins and that the mouse Sry ORF can function as a transcriptional activator with separable DNA-binding and activator domains.

  13. RAD51AP1-deficiency in vertebrate cells impairs DNA replication.

    PubMed

    Parplys, Ann C; Kratz, Katja; Speed, Michael C; Leung, Stanley G; Schild, David; Wiese, Claudia

    2014-12-01

    RAD51-associated protein 1 (RAD51AP1) is critical for homologous recombination (HR) by interacting with and stimulating the activities of the RAD51 and DMC1 recombinases. In human somatic cells, knockdown of RAD51AP1 results in increased sensitivity to DNA damaging agents and to impaired HR, but the formation of DNA damage-induced RAD51 foci is unaffected. Here, we generated a genetic model system, based on chicken DT40 cells, to assess the phenotype of fully inactivated RAD51AP1 in vertebrate cells. Targeted inactivation of both RAD51AP1 alleles has no effect on either viability or doubling-time in undamaged cells, but leads to increased levels of cytotoxicity after exposure to cisplatin or to ionizing radiation. Interestingly, ectopic expression of GgRAD51AP1, but not of HsRAD51AP1 is able to fully complement in cell survival assays. Notably, in RAD51AP1-deficient DT40 cells the resolution of DNA damage-induced RAD51 foci is greatly slowed down, while their formation is not impaired. We also identify, for the first time, an important role for RAD51AP1 in counteracting both spontaneous and DNA damage-induced replication stress. In human and in chicken cells, RAD51AP1 is required to maintain wild type speed of replication fork progression, and both RAD51AP1-depleted human cells and RAD51AP1-deficient DT40 cells respond to replication stress by a slow-down of replication fork elongation rates. However, increased firing of replication origins occurs in RAD51AP1-/- DT40 cells, likely to ensure the timely duplication of the entire genome. Taken together, our results may explain why RAD51AP1 commonly is overexpressed in tumor cells and tissues, and we speculate that the disruption of RAD51AP1 function could be a promising approach in targeted tumor therapy. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Chemotherapeutic Potential of 2-[Piperidinoethoxyphenyl]-3-Phenyl-2H-Benzo(b)pyran in Estrogen Receptor- Negative Breast Cancer Cells: Action via Prevention of EGFR Activation and Combined Inhibition of PI-3-K/Akt/FOXO and MEK/Erk/AP-1 Pathways

    PubMed Central

    Saxena, Ruchi; Chandra, Vishal; Manohar, Murli; Hajela, Kanchan; Debnath, Utsab; Prabhakar, Yenamandra S.; Saini, Karan Singh; Konwar, Rituraj; Kumar, Sandeep; Megu, Kaling; Roy, Bal Gangadhar; Dwivedi, Anila

    2013-01-01

    Inhibition of epidermal growth factor receptor (EGFR) signaling is considered to be a promising treatment strategy for estrogen receptor (ER)-negative breast tumors. We have investigated here the anti-breast cancer properties of a novel anti-proliferative benzopyran compound namely, 2-[piperidinoethoxyphenyl]-3-phenyl-2H-benzo(b)pyran (CDRI-85/287) in ER- negative and EGFR- overexpressing breast cancer cells. The benzopyran compound selectively inhibited the EGF-induced growth of MDA-MB 231 cells and ER-negative primary breast cancer cell culture. The compound significantly reduced tumor growth in xenograft of MDA-MB 231 cells in nude mice. The compound displayed better binding affinity for EGFR than inhibitor AG1478 as demonstrated by molecular docking studies. CDRI-85/287 significantly inhibited the activation of EGFR and downstream effectors MEK/Erk and PI-3-K/Akt. Subsequent inhibition of AP-1 promoter activity resulted in decreased transcription activation and expression of c-fos and c-jun. Dephosphorylation of downstream effectors FOXO-3a and NF-κB led to increased expression of p27 and decreased expression of cyclin D1 which was responsible for decreased phosphorylation of Rb and prevented the transcription of E2F- dependent genes involved in cell cycle progression from G1/S phase. The compound induced apoptosis via mitochondrial pathway and it also inhibited EGF-induced invasion of MDA-MB 231 cells as evidenced by decreased activity of MMP-9 and expression of CTGF. These results indicate that benzopyran compound CDRI-85/287 could constitute a powerful new chemotherapeutic agent against ER-negative and EGFR over-expressing breast tumors. PMID:23840429

  15. AP-1/σ1A and AP-1/σ1B adaptor-proteins differentially regulate neuronal early endosome maturation via the Rab5/Vps34-pathway

    PubMed Central

    Candiello, Ermes; Kratzke, Manuel; Wenzel, Dirk; Cassel, Dan; Schu, Peter

    2016-01-01

    The σ1 subunit of the AP-1 clathrin-coated-vesicle adaptor-protein complex is expressed as three isoforms. Tissues express σ1A and one of the σ1B and σ1C isoforms. Brain is the tissue with the highest σ1A and σ1B expression. σ1B-deficiency leads to severe mental retardation, accumulation of early endosomes in synapses and fewer synaptic vesicles, whose recycling is slowed down. AP-1/σ1A and AP-1/σ1B regulate maturation of these early endosomes into multivesicular body late endosomes, thereby controlling synaptic vesicle protein transport into a degradative pathway. σ1A binds ArfGAP1, and with higher affinity brain-specific ArfGAP1, which bind Rabex-5. AP-1/σ1A-ArfGAP1-Rabex-5 complex formation leads to more endosomal Rabex-5 and enhanced, Rab5GTP-stimulated Vps34 PI3-kinase activity, which is essential for multivesicular body endosome formation. Formation of AP-1/σ1A-ArfGAP1-Rabex-5 complexes is prevented by σ1B binding of Rabex-5 and the amount of endosomal Rabex-5 is reduced. AP-1 complexes differentially regulate endosome maturation and coordinate protein recycling and degradation, revealing a novel molecular mechanism by which they regulate protein transport besides their established function in clathrin-coated-vesicle formation. PMID:27411398

  16. AP-1/σ1A and AP-1/σ1B adaptor-proteins differentially regulate neuronal early endosome maturation via the Rab5/Vps34-pathway.

    PubMed

    Candiello, Ermes; Kratzke, Manuel; Wenzel, Dirk; Cassel, Dan; Schu, Peter

    2016-07-14

    The σ1 subunit of the AP-1 clathrin-coated-vesicle adaptor-protein complex is expressed as three isoforms. Tissues express σ1A and one of the σ1B and σ1C isoforms. Brain is the tissue with the highest σ1A and σ1B expression. σ1B-deficiency leads to severe mental retardation, accumulation of early endosomes in synapses and fewer synaptic vesicles, whose recycling is slowed down. AP-1/σ1A and AP-1/σ1B regulate maturation of these early endosomes into multivesicular body late endosomes, thereby controlling synaptic vesicle protein transport into a degradative pathway. σ1A binds ArfGAP1, and with higher affinity brain-specific ArfGAP1, which bind Rabex-5. AP-1/σ1A-ArfGAP1-Rabex-5 complex formation leads to more endosomal Rabex-5 and enhanced, Rab5(GTP)-stimulated Vps34 PI3-kinase activity, which is essential for multivesicular body endosome formation. Formation of AP-1/σ1A-ArfGAP1-Rabex-5 complexes is prevented by σ1B binding of Rabex-5 and the amount of endosomal Rabex-5 is reduced. AP-1 complexes differentially regulate endosome maturation and coordinate protein recycling and degradation, revealing a novel molecular mechanism by which they regulate protein transport besides their established function in clathrin-coated-vesicle formation.

  17. Knockdown of CDK2AP1 in Primary Human Fibroblasts Induces p53 Dependent Senescence

    PubMed Central

    Alsayegh, Khaled N.; Gadepalli, Venkat S.; Iyer, Shilpa; Rao, Raj R.

    2015-01-01

    Cyclin Dependent Kinase-2 Associated Protein-1 (CDK2AP1) is known to be a tumor suppressor that plays a role in cell cycle regulation by sequestering monomeric CDK2, and targeting it for proteolysis. A reduction of CDK2AP1 expression is considered to be a negative prognostic indicator in patients with oral squamous cell carcinoma and also associated with increased invasion in human gastric cancer tissue. CDK2AP1 overexpression was shown to inhibit growth, reduce invasion and increase apoptosis in prostate cancer cell lines. In this study, we investigated the effect of CDK2AP1 downregulation in primary human dermal fibroblasts. Using a short-hairpin RNA to reduce its expression, we found that knockdown of CDK2AP1in primary human fibroblasts resulted in reduced proliferation and in the induction of senescence associated beta-galactosidase activity. CDK2AP1 knockdown also resulted in a significant reduction in the percentage of cells in the S phase and an accumulation of cells in the G1 phase of the cell cycle. Immunocytochemical analysis also revealed that the CDK2AP1 knockdown significantly increased the percentage of cells that exhibited γ-H2AX foci, which could indicate presence of DNA damage. CDK2AP1 knockdown also resulted in increased mRNA levels of p53, p21, BAX and PUMA and p53 protein levels. In primary human fibroblasts in which p53 and CDK2AP1 were simultaneously downregulated, there was: (a) no increase in senescence associated beta-galactosidase activity, (b) decrease in the number of cells in the G1-phase and increase in number of cells in the S-phase of the cell cycle, and (c) decrease in the mRNA levels of p21, BAX and PUMA when compared with CDK2AP1 knockdown only fibroblasts. Taken together, this suggests that the observed phenotype is p53 dependent. We also observed a prominent increase in the levels of ARF protein in the CDK2AP1 knockdown cells, which suggests a possible role of ARF in p53 stabilization following CDK2AP1 knockdown. Altogether

  18. Linking Smads and transcriptional activation.

    PubMed

    Inman, Gareth J

    2005-02-15

    TGF-beta1 (transforming growth factor-beta1) is the prototypical member of a large family of pleiotropic cytokines that regulate diverse biological processes during development and adult tissue homoeostasis. TGF-beta signals via membrane bound serine/threonine kinase receptors which transmit their signals via the intracellular signalling molecules Smad2, Smad3 and Smad4. These Smads contain conserved MH1 and MH2 domains separated by a flexible linker domain. Smad2 and Smad3 act as kinase substrates for the receptors, and, following phosphorylation, they form complexes with Smad4 and translocate to the nucleus. These Smad complexes regulate gene expression and ultimately determine the biological response to TGF-beta. In this issue of the Biochemical Journal, Wang et al. have shown that, like Smad4, the linker domain of Smad3 contains a Smad transcriptional activation domain. This is capable of recruiting the p300 transcriptional co-activator and is required for Smad3-dependent transcriptional activation. This study raises interesting questions about the nature and regulation of Smad-regulated gene activation and elevates the status of the linker domain to rival that of the much-lauded MH1 and MH2 domains.

  19. The regulation of hepcidin expression by serum treatment: requirements of the BMP response element and STAT- and AP-1-binding sites.

    PubMed

    Kanamori, Yohei; Murakami, Masaru; Matsui, Tohru; Funaba, Masayuki

    2014-11-10

    Expression of hepcidin, a central regulator of systemic iron metabolism, is transcriptionally regulated by the bone morphogenetic protein (BMP) pathway. However, the factors other than the BMP pathway also participate in the regulation of hepcidin expression. In the present study, we show that serum treatment increased hepcidin expression and transcription without inducing the phosphorylation of Smad1/5/8 in primary hepatocytes, HepG2 cells or Hepa1-6 cells. Co-treatment with LDN-193189, an inhibitor of the BMP type I receptor, abrogated this hepcidin induction. Reporter assays using mutated reporters revealed the involvement of the BMP response element-1 (BMP-RE1) and signal transducers and activator of transcription (STAT)- and activator protein (AP)-1-binding sites in serum-induced hepcidin transcription in HepG2 cells. Serum treatment induced the expression of the AP-1 components c-fos and junB in primary hepatocytes and HepG2 cells. Forced expression of c-fos or junB enhanced the response of hepcidin transcription to serum treatment. By contrast, the expression of dominant negative (dn)-c-fos and dn-junB decreased hepcidin transcription. The present study reveals that serum contains factors stimulating hepcidin transcription. Basal BMP activity is essential for the serum-induced hepcidin transcription, although serum treatment does not stimulate the BMP pathway. The induction of c-fos and junB by serum treatment stimulates hepcidin transcription, through possibly cooperation with BMP-mediated signaling. Considering that AP-1 is induced by various stimuli, the present results suggest that hepcidin expression is regulated by more diverse factors than had been previously considered.

  20. Growth inhibition of non-small cell lung cancer cells by AP-1 blockade using a cJun dominant-negative mutant

    PubMed Central

    Shimizu, Y; Kinoshita, I; Kikuchi, J; Yamazaki, K; Nishimura, M; Birrer, M J; Dosaka-Akita, H

    2008-01-01

    cJun, a major constituent of AP-1 transcription factor transducing multiple mitogen growth signals, is frequently overexpressed in non-small cell lung cancers (NSCLCs). The purpose of this study is to determine the effects of AP-1 blockade on the growth of NSCLC cells using a cJun dominant-negative mutant, TAM67. Transiently transfected TAM67 inhibited AP-1 transcriptional activity in NSCLC cell lines, NCI-H1299 (H1299), A549 and NCI-H520 (H520). The colony-forming efficiency of H1299 and A549 was reduced by TAM67, while that of H520 was not. To elucidate the effects of TAM67 on the growth of H1299, we established H1299 clone cells that expressed TAM67 under the control of a doxycycline-inducible promoter. In the H1299 clone cells, the induced TAM67 inhibited anchorage-dependent growth by promoting G1 cell-cycle block, but not by apoptosis. The induced TAM67 decreased the expression of a cell-cycle regulatory protein, cyclin A. TAM67 also inhibited anchorage-independent growth of these cells. Furthermore, TAM67 reduced growth of established xenograft tumours from these cells in nude mice. These results suggest that AP-1 plays an essential role in the growth of at least some of NSCLC cells. PMID:18283312

  1. Molecular basis for the direct inhibition of AP-1 DNA binding by 15-deoxy-Delta 12,14-prostaglandin J2.

    PubMed

    Pérez-Sala, Dolores; Cernuda-Morollón, Eva; Cañada, F Javier

    2003-12-19

    Cyclopentenone prostaglandins may interfere with cellular functions by multiple mechanisms. The cyclopentenone 15-deoxy-Delta 12,14-prostaglandin J2 (15d-PGJ2) has been reported to inhibit the activity of the transcription factor AP-1 in several experimental settings. We have explored the possibility of a direct interaction of 15d-PGJ2 with AP-1 proteins. Here we show that 15d-PGJ2 covalently modifies c-Jun and directly inhibits the DNA binding activity of AP-1. The modification of c-Jun occurs both in vitro and in intact cells as detected by labeling with biotinylated 15d-PGJ2 and mass spectrometry analysis. Attachment of the cyclopentenone prostaglandin occurs at cysteine 269, which is located in the c-Jun DNA binding domain. In addition, 15d-PGJ2 can promote the oligomerization of a fraction of c-Jun through the formation of intermolecular disulfide bonds or 15d-PGJ2-bonded dimers. Our results identify a novel site of interaction of 15d-PGJ2 with the AP-1 activation pathway that may contribute to the complex effects of cyclopentenone prostaglandins on the cellular response to pro-inflammatory agents. They also show the first evidence for the induction of protein cross-linking by 15d-PGJ2.

  2. Effect of estrogen and tamoxifen on the expression pattern of AP-1 factors in MCF-7 cells: role of c-Jun, c-Fos, and Fra-1 in cell cycle regulation.

    PubMed

    Babu, R L; Naveen Kumar, M; Patil, Rajeshwari H; Devaraju, K S; Ramesh, Govindarajan T; Sharma, S Chidananda

    2013-08-01

    The activated transcription factor ERα plays an important role in the breast development and progression of cancer. In a non-classical pathway ER interacts with other transcription factors AP-1, NFkB, SP1, etc. AP-1 transcription factors control rapid responses of mammalian cells to stimuli that impact proliferation, differentiation, and transformation. AP-1 factors are leucine zipper proteins belonging to members of the Jun family (c-Jun, JunB, and JunD) and Fos family (c-Fos, FosB, Fra-1, and Fra-2) proteins. Although AP-1 factors are well characterized, not much is known about the expression pattern of the AP-1 factors in breast cancer cells. Hence to determine which AP-1 factors are expressed and regulated by estrogen, we used human breast cancer MCF-7 cells as in vitro model system. The MCF-7 cells were treated with or without estradiol-17β (E2) or antiestrogen tamoxifen (TMX) and the cell proliferation and viability was assessed by MTT assay. The expression of different AP-1 factors was analyzed by semi-quantitative RT-PCR. The cells treated with E2 found to increase the cell proliferation by more than 35 % and TMX an antiestrogen decreased by 29 % compared to control. The E2 found to induce the expression of c-Jun, Fra-1, and c-Fos, while TMX decreased the expression. In addition TMX also decreased the mRNA levels of Jun-D and Fra-2. These results suggest that the AP-1 factors c-Jun, c-Fos, and Fra-1 may be involved in the proliferation and transformation of MCF-7 cells. E2 also found to induce cyclin D1 and cyclin E1 mRNA transcripts of cell cycle regulators while TMX significantly decreased compared to control. Further E2 induced the anti-apoptotic Bcl-2 and TMX decreased mRNA transcripts. The data presented here support the E2-ERα-mediated MCF-7 cell proliferation and confirms the role of AP-1 factors in cell cycle regulation.

  3. Characterization of human constitutive photomorphogenesis protein 1, a RING finger ubiquitin ligase that interacts with Jun transcription factors and modulates their transcriptional activity.

    PubMed

    Bianchi, Elisabetta; Denti, Simona; Catena, Raffaella; Rossetti, Grazisa; Polo, Simona; Gasparian, Sona; Putignano, Stella; Rogge, Lars; Pardi, Ruggero

    2003-05-30

    RING finger proteins have been implicated in many fundamental cellular processes, including the control of gene expression. A key regulator of light-dependent development in Arabidopsis thaliana is the constitutive photomorphogenesis protein 1 (atCOP1), a RING finger protein that plays an essential role in translating light/dark signals into specific changes in gene transcription. atCOP1 binds the basic leucine zipper factor HY5 and suppresses its transcriptional activity through a yet undefined mechanism that results in HY5 degradation in response to darkness. Furthermore, the pleiotropic phenotype of atCOP1 mutants indicates that atCOP1 may be a central regulator of several transcriptional pathways. Here we report the cloning and characterization of the human orthologue of atCOP1. Human COP1 (huCOP1) distributes both to the cytoplasm and the nucleus of cells and shows a striking degree of sequence conservation with atCOP1, suggesting the possibility of a functional conservation as well. In co-immunoprecipitation assays huCOP1 specifically binds basic leucine zipper factors of the Jun family. As a functional consequence of this interaction, expression of huCOP1 in mammalian cells down-regulates c-Jun-dependent transcription and the expression of the AP-1 target genes, urokinase and matrix metalloproteinase 1. The RING domain of huCOP1 displays ubiquitin ligase activity in an autoubiquitination assay in vitro; however, suppression of AP-1-dependent transcription by huCOP1 occurs in the absence of changes in c-Jun protein levels, suggesting that this inhibitory effect is independent of c-Jun degradation. Our findings indicate that huCOP1 is a novel regulator of AP-1-dependent transcription sharing the important properties of Arabidopsis COP1 in the control of gene expression.

  4. EFFECT OF ARSENIC ON TRANSCRIPTION FACTOR AP-1 AND NF-KAPPA B DNA BINDING ACTIVITY AND RELATED GENE EXPRESSION. (R826135)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  5. Quassinoid inhibition of AP-1 function does not correlate with cytotoxicity or protein synthesis inhibition.

    PubMed

    Beutler, John A; Kang, Moon-Il; Robert, Francis; Clement, Jason A; Pelletier, Jerry; Colburn, Nancy H; McKee, Tawnya C; Goncharova, Ekaterina; McMahon, James B; Henrich, Curtis J

    2009-03-27

    Several quassinoids were identified in a high-throughput screening assay as inhibitors of the transcription factor AP-1. Further biological characterization revealed that while their effect was not specific to AP-1, protein synthesis inhibition and cell growth assays were inconsistent with a mechanism of simple protein synthesis inhibition. Numerous plant extracts from the plant family Simaroubaceae were also identified in the same screen; bioassay-guided fractionation of one extract (Ailanthus triphylla) yielded two known quassinoids, ailanthinone (3) and glaucarubinone (4), which were also identified in the pure compound screening procedure.

  6. Quassinoid Inhibition of AP-1 Function Does Not Correlate with Cytotoxicity or Protein Synthesis Inhibition†

    PubMed Central

    Beutler, John A.; Kang, Moon-Il; Robert, Francis; Clement, Jason A.; Pelletier, Jerry; Colburn, Nancy H.; McKee, Tawnya C.; Goncharova, Ekaterina; McMahon, James B.; Henrich, Curtis J.

    2010-01-01

    Several quassinoids were identified in a high-throughput screening assay as inhibitors of the transcription factor AP-1. Further biological characterization revealed that while their effect was not specific to AP-1, protein synthesis inhibition and cell growth assays were inconsistent with a mechanism of simple protein synthesis inhibition. Numerous plant extracts from the plant family Simaroubaceae were also identified in the same screen; bioassay-guided fractionation of one extract (Ailanthus triphylla) yielded two known quassinoids, ailanthinone (3) and glaucarubinone (4), which were also identified in the pure compound screening procedure. PMID:19199792

  7. KPNB1-mediated nuclear import is required for motility and inflammatory transcription factor activity in cervical cancer cells

    PubMed Central

    Stelma, Tamara; Leaner, Virna D.

    2017-01-01

    Karyopherin β1 is a nuclear import protein involved in the transport of proteins containing a nuclear localisation sequence. Elevated Karyopherin β1 expression has been reported in cancer and transformed cells and is essential for cancer cell proliferation and survival. Transcription factors such as NFĸB and AP-1 contain a nuclear localisation sequence and initiate the expression of multiple factors associated with inflammation and cancer cell biology. Our study investigated the effect of inhibiting nuclear import via Karyopherin β1 on cancer cell motility and inflammatory signaling using siRNA and the novel small molecule, Inhibitor of Nuclear Import-43, INI-43. Inhibition of Karyopherin β1 led to reduced migration and invasion of cervical cancer cells. Karyopherin β1 is essential for the translocation of NFĸB into the nucleus as nuclear import inhibition caused its cytoplasmic retention and decreased transcriptional activity. A similar decrease was seen in AP-1 transcriptional activity upon Karyopherin β1 inhibition. Consequently reduced interleukin-6, interleukin-1 beta, tumour necrosis factor alpha and granulocyte macrophage colony stimulating factor expression, target genes of NFkB and AP-1, was observed. Migration studies inhibiting individual transcription factors suggested that INI-43 may affect a combination of signaling events. Our study provides further evidence that inhibiting KPNB1 has anti-cancer effects and shows promise as a chemotherapeutic target. PMID:28427184

  8. The FUS3 MAPK signaling pathway of the citrus pathogen Alternaria alternata functions independently or cooperatively with the fungal redox-responsive AP1 regulator for diverse developmental, physiological and pathogenic processes.

    PubMed

    Lin, Ching-Hsuan; Yang, Siwy Ling; Wang, Nan-Yi; Chung, Kuang-Ren

    2010-04-01

    Alternaria alternata, the fungus that causes citrus brown spot, invades its hosts primarily through the production and action of a host-selective ACT toxin that kills citrus cells prior to invasion. In this study, we show that, in the tangerine pathotype of A. alternata, a mitogen-activated protein kinase (MAPK)-mediated signaling pathway governs a number of biological functions, either separately or in a cooperative manner, with the AaAP1 gene encoding a transcription regulator. The reported MAPK is encoded by the AaFUS3 gene, which we show to be necessary for conidial development, resistance to copper fungicides, melanin biosynthesis, and particularly, for elaboration of the penetration process. In contrast, AaFUS3 negatively controls salt tolerance and production of several hydrolytic enzymes. AaFUS3 has no apparent role in the biosynthesis of host-selective toxin or in resistance to oxidative stress. Both AaAP1 and AaFUS3 are required for fungal resistance to 2,3,5-triiodobenzoic acid (TIBA), 2-chloro-5-hydroxypyridine (CHP), diethyl maleate (DEM), and many pyridine-containing compounds. A strain with mutations in both AaAP1 and AaFUS3 displayed an increased sensitivity to these compounds. Expression of the AaAP1 and AaFUS3 genes and phosphorylation of AaFUS3 were also induced by CHP, DEM, or TIBA. Expression of two genes coding for a putative MFS transporter was coordinately regulated by AaAP1 and AaFUS3. The AaAP1::sGFP (synthetic green fluorescent protein) fusion protein became localized in the nucleus in response to CHP or TIBA. Inactivation of the AaAP1 gene, however, promoted phosphorylation of AaFUS3. Taken together, our results indicate that A. alternata utilizes specialized or synergistic regulatory interactions between the AP1 and MAPK signaling pathways for diverse physiological functions.

  9. Bryostatin-1 stimulates the transcription of cyclooxygenase-2: evidence for an activator protein-1-dependent mechanism.

    PubMed

    De Lorenzo, Mariana S; Yamaguchi, Kentaro; Subbaramaiah, Kotha; Dannenberg, Andrew J

    2003-10-15

    Bryostatin-1 (bryostatin) is a macrocyclic lactone derived from Bugula neritina, a marine bryozoan. On the basis of the strength of in vitro and animal studies, bryostatin is being investigated as a possible treatment for a variety of human malignancies. Severe myalgias are a common dose-limiting side effect. Because cyclooxygenase-2 (COX-2)-derived prostaglandins can cause pain, we investigated whether bryostatin induced COX-2. Bryostatin (1-10 nM) induced COX-2 mRNA, COX-2 protein, and prostaglandin biosynthesis. These effects were observed in macrophages as well as in a series of human cancer cell lines. Transient transfections localized the stimulatory effects of bryostatin to the cyclic AMP response element of the COX-2 promoter. Electrophoretic mobility shift assays and supershift experiments revealed a marked increase in the binding of activator protein-1 (AP-1)(c-Jun/c-Fos) to the cyclic AMP response element of the COX-2 promoter. Pharmacological and transient transfection studies indicated that bryostatin stimulated COX-2 transcription via the protein kinase C-->mitogen-activated protein kinase-->AP-1 pathway. All-trans-retinoic acid, a prototypic AP-1 antagonist, blocked bryostatin-mediated induction of COX-2. Taken together, these results suggest that bryostatin-mediated induction of COX-2 can help to explain the myalgias that are commonly associated with treatment. Moreover, it will be worthwhile to evaluate whether the addition of a selective COX-2 inhibitor can increase the antitumor activity of bryostatin.

  10. AP-1 Inhibition by SR 11302 Protects Human Hepatoma HepG2 Cells from Bile Acid-Induced Cytotoxicity by Restoring the NOS-3 Expression

    PubMed Central

    González-Rubio, Sandra; Linares, Clara I.; Aguilar-Melero, Patricia; Rodríguez-Perálvarez, Manuel; Montero-Álvarez, José L.

    2016-01-01

    The harmful effects of bile acid accumulation occurring during cholestatic liver diseases have been associated with oxidative stress increase and endothelial nitric oxide synthase (NOS-3) expression decrease in liver cells. We have previously reported that glycochenodeoxycholic acid (GCDCA) down-regulates gene expression by increasing SP1 binding to the NOS-3 promoter in an oxidative stress dependent manner. In the present study, we aimed to investigate the role of transcription factor (TF) AP-1 on the NOS-3 deregulation during GCDCA-induced cholestasis. The cytotoxic response to GCDCA was characterized by 1) the increased expression and activation of TFs cJun and c-Fos; 2) a higher binding capability of these at position -666 of the NOS-3 promoter; 3) a decrease of the transcriptional activity of the promoter and the expression and activity of NOS-3; and 4) the expression increase of cyclin D1. Specific inhibition of AP-1 by the retinoid SR 11302 counteracted the cytotoxic effects induced by GCDCA while promoting NOS-3 expression recovery and cyclin D1 reduction. NOS activity inhibition by L-NAME inhibited the protective effect of SR 11302. Inducible NOS isoform was no detected in this experimental model of cholestasis. Our data provide direct evidence for the involvement of AP-1 in the NOS-3 expression regulation during cholestasis and define a critical role for NOS-3 in regulating the expression of cyclin D1 during the cell damage induced by bile acids. AP-1 appears as a potential therapeutic target in cholestatic liver diseases given its role as a transcriptional repressor of NOS-3. PMID:27490694

  11. Possible roles of the AP-1 site in the cytosolic T3 binding protein promoter and insights into its physiological significance.

    PubMed

    Suzuki, S; Nishio, S-I; Ishii, H; Sekido, T; Takeshige, K; Ohkubo, Y; Hiwatashi, D; Takeda, T; Komatsu, M

    2013-07-01

    Cytosolic 3,5,3'-triiodo-l-thyronine-binding protein plays pivotal roles in the regulation of intracellular 3,5,3'-triiodo-l-thyronine concentration in vivo. The expression of the protein, which is identical to μ-crystallin, is regulated by various factors. To elucidate the mechanisms of its expression, we evaluated the promoter transactivity and insulin signaling via the AP-1 site in the promoter. The isolated 600 bp human and 1976 bp mouse 5'-flanking regions were cloned in a luciferase reporter plasmid. The luciferase activity was estimated in GH3, dRLh-84, HEK293, and insulin receptor-overexpressing CHO-IR cells. The effects of 12-O-tetradecanoylphorbol 13-acetate and insulin on μ-crystallin mRNA expression were evaluated in various cells. The region between -200 and the transcriptional start site was crucial for constitutive expression in μ-crystallin-expressing dRLh-84 cells. This region contained an AP-1 site. 12-O-Tetradecanoylphorbol 13-acetate increased the level of μ-crystallin mRNA expression in HEK 293 cells. The compound also increased luciferase activity through the promoter. Mutation in the AP1 site diminished the response to the compound. The promoter was also activated by insulin treatment in CHO-IR cells. Insulin treatment increased μ-crystallin mRNA expression in Raw264.7 cells, but decreased in HEK293, P19, and dRLH-84 cells. The expression of μ-crystallin was regulated through the AP-1 site in the promoter. The signals related to AP-1 activation, such as insulin signaling may have diverse effects on μ-crystallin mRNA expression.

  12. The Arabidopsis floral meristem identity genes AP1, AGL24 and SVP directly repress class B and C floral homeotic genes.

    PubMed

    Gregis, Veronica; Sessa, Alice; Dorca-Fornell, Carmen; Kater, Martin M

    2009-11-01

    During the initial stages of flower development, floral meristems increase in size without the formation of floral organs. When a critical meristem size is reached, the floral meristem begins to develop the floral organs. The first stages of flower development are characterized by the expression of genes such as Apetala 1 (AP1), cauliflower (CAL), AGAMOUS-LIKE 24 (AGL24) and short vegetative phase (SVP). We have shown that AP1, AGL24 and SVP act redundantly to control the identity of the floral meristem and to repress expression of class B, C and E genes. Recently, it was shown that class E gene repression was direct and established by two independent pathways. We show here that repression of class B and C genes is also directly established by a co-repressor complex that comprises LEUNIG (LUG), SEUSS (SEU) and the MADS box dimers AP1-AGL24 and AP1-SVP. Furthermore, we show that the distantly related suppressor of overexpression of CO 1 (SOC1) MADS box gene can complement for the loss of AGL24 and SVP activity; however, under normal conditions, this transcription factor does not play a role during the early stages of flower development.

  13. AP-1 and clathrin are essential for secretory granule biogenesis in Drosophila

    PubMed Central

    Burgess, Jason; Jauregui, Miluska; Tan, Julie; Rollins, Janet; Lallet, Sylvie; Leventis, Peter A.; Boulianne, Gabrielle L.; Chang, Henry C.; Le Borgne, Roland; Krämer, Helmut; Brill, Julie A.

    2011-01-01

     Regulated secretion of hormones, digestive enzymes, and other biologically active molecules requires the formation of secretory granules. Clathrin and the clathrin adaptor protein complex 1 (AP-1) are necessary for maturation of exocrine, endocrine, and neuroendocrine secretory granules. However, the initial steps of secretory granule biogenesis are only minimally understood. Powerful genetic approaches available in the fruit fly Drosophila melanogaster were used to investigate the molecular pathway for biogenesis of the mucin-containing “glue granules” that form within epithelial cells of the third-instar larval salivary gland. Clathrin and AP-1 colocalize at the trans-Golgi network (TGN) and clathrin recruitment requires AP-1. Furthermore, clathrin and AP-1 colocalize with secretory cargo at the TGN and on immature granules. Finally, loss of clathrin or AP-1 leads to a profound block in secretory granule formation. These findings establish a novel role for AP-1– and clathrin-dependent trafficking in the biogenesis of mucin-containing secretory granules. PMID:21490149

  14. Baicalein reduces angiogenesis in the inflammatory microenvironment via inhibiting the expression of AP-1

    PubMed Central

    Huang, Yujie; Miao, Zhaorui; Hu, Yang; Yuan, Yang; Zhou, Yuxin; Wei, Libin; Zhao, Kai; Guo, Qinglong; Lu, Na

    2017-01-01

    Increasing clinical and experimental studies have demonstrated that refractory chronic inflammation will result in malignant tumor and anti-angiogenic therapy may be an effective way to thwart the progression. Baicalein, one of the major active flavanoids found in Scutellaria baicalensis Georgi, has been exhibited potent anti-inflammation and anti-tumor effects by reducing angiogenesis. However, the exact mechanism of baicalein on endothelial cells in inflammatory microenvironment was not clear yet. Here, we investigated the anti-angiogenic effect of baicalein by incubating human umbilical vein endothelial cells (HUVECs) with THP-1 conditioned medium in vitro. The tube formation of HUVECs and microvessel outgrowth of rat aorta were attenuated, as well as the number of newly formed blood vessels in chicken chorioallantoic membrane (CAM) was reduced by baicalein. This anti-angiogenic effect was mainly on account of the inhibited motility, migration and invasion of HUVECs. In addition, mechanistic studies showed that baicalein could bind to AP-1 directly and the expression of c-Jun and c-Fos in HUVECs was reduced, accompanied by their increased proteasomal degradation. Besides, baicalein suppressed the nuclear translation, heterodimer formation and DNA binding affinity of c-Jun and c-Fos. What's more, the anti-angiogenic effect of baicalein was further confirmed by matrigel plug assay in vivo. Taken together, our study demonstrated that baicalein could exert its anti-angiogenic effect in the inflammation microenvironment via inhibiting the transcriptional activity of AP-1, which suggested that baicalein might be an alternative treatment against refractory chronic inflammation. PMID:27903990

  15. Erg and AP-1 as determinants of glucocorticoid response in acute lymphoblastic leukemia.

    PubMed

    Chen, D W-C; Saha, V; Liu, J-Z; Schwartz, J-M; Krstic-Demonacos, M

    2013-06-20

    Glucocorticoids (GCs) are among the most widely prescribed medications in clinical practice. The beneficial effects of GCs in acute lymphoblastic leukemia (ALL) are based on their ability to induce apoptosis, but the underlying transcriptional mechanisms remain poorly defined. Computational modeling has enormous potential in the understanding of biological processes such as apoptosis and the discovery of novel regulatory mechanisms. We here present an integrated analysis of gene expression kinetic profiles using microarrays from GC sensitive and resistant ALL cell lines and patients, including newly generated and previously published data sets available from the Gene Expression Omnibus. By applying time-series clustering analysis in the sensitive ALL CEM-C7-14 cells, we identified 358 differentially regulated genes that we classified into 15 kinetic profiles. We identified GC response element (GRE) sequences in 33 of the upregulated known or potential GC receptor (GR) targets. Comparative study of sensitive and resistant ALL showed distinct gene expression patterns and indicated unexpected similarities between sensitivity-restored and resistant ALL. We found that activator protein 1 (AP-1), Ets related gene (Erg) and GR pathways were differentially regulated in sensitive and resistant ALL. Erg protein levels were substantially higher in CEM-C1-15-resistant cells, c-Jun was significantly induced in sensitive cells, whereas c-Fos was expressed at low levels in both. c-Jun was recruited on the AP-1 site on the Bim promoter, whereas a transient Erg occupancy on the GR promoter was detected. Inhibition of Erg and activation of GR lead to increased apoptosis in both sensitive and resistant ALL. These novel findings significantly advance our understanding of GC sensitivity and can be used to improve therapy of leukemia.

  16. Over-expression of the PaAP1 gene from sweet cherry (Prunus avium L.) causes early flowering in Arabidopsis thaliana.

    PubMed

    Wang, Jing; Zhang, Xiaoming; Yan, Guohua; Zhou, Yu; Zhang, Kaichun

    2013-02-15

    A homologue of SQUAMOSA/APETALA1, designated PaAP1, was isolated from Prunus avium by reverse transcription-PCR (RT-PCR). The full length of PaAP1 cDNA is 753 bp, and it codes for a polypeptide of 250 amino acid residues. Sequence comparison revealed that PaAP1 belongs to the MADS-box gene family. Phylogenetic analysis indicated that PaAP1 shared the highest identity with SQUA/AP1 homologues from Prunus serrulata. Real-time fluorescence quantitative PCR analysis showed that PaAP1 was expressed at high levels in petal, sepal, style, and flower buds, which was slightly different from the expression pattern of AP1 of Arabidopsis thaliana. To characterize the functions of PaAP1, we assessed Arabidopsis transformed with 35S::PaAP1. A total of 8 transgenic T(1) lines with an early flowering phenotype were obtained, and a 3:1 segregation ratio of flowering time was observed in the T(2) generation of 4 lines. This study provides the first functional analysis of an SQUA/AP1 homolog from P. avium and suggests that PaAP1 is potentially useful for shortening the juvenile period in sweet cherry. Copyright © 2012 Elsevier GmbH. All rights reserved.

  17. Pregnenolone sulfate activates basic region leucine zipper transcription factors in insulinoma cells: role of voltage-gated Ca2+ channels and transient receptor potential melastatin 3 channels.

    PubMed

    Müller, Isabelle; Rössler, Oliver G; Thiel, Gerald

    2011-12-01

    The neurosteroid pregnenolone sulfate activates a signaling cascade in insulinoma cells involving activation of extracellular signal-regulated protein kinase and enhanced expression of the transcription factor Egr-1. Here, we show that pregnenolone sulfate stimulation leads to a significant elevation of activator protein-1 (AP-1) activity in insulinoma cells. Expression of the basic region leucine zipper (bZIP) transcription factors c-Jun and c-Fos is up-regulated in insulinoma cells and pancreatic β-cells in primary culture after pregnenolone sulfate stimulation. Up-regulation of a chromatin-embedded c-Jun promoter/luciferase reporter gene transcription in pregnenolone sulfate-stimulated insulinoma cells was impaired when the AP-1 binding sites were mutated, indicating that these motifs function as pregnenolone sulfate response elements. In addition, phosphorylation of cAMP response element (CRE)-binding protein is induced and transcription of a CRE-controlled reporter gene is stimulated after pregnenolone sulfate treatment, indicating that the CRE functions as a pregnenolone sulfate response element as well. Pharmacological and genetic experiments revealed that both L-type Ca(2+) channels and transient receptor potential melastatin 3 (TRPM3) channels are essential for connecting pregnenolone sulfate stimulation with enhanced AP-1 activity and bZIP-mediated transcription in insulinoma cells. In contrast, pregnenolone sulfate stimulation did not enhance AP-1 activity or c-Jun and c-Fos expression in pituitary corticotrophs that express functional L-type Ca(2+) channels but only trace amounts of TRPM3. We conclude that expression of L-type Ca(2+) channels is not sufficient to activate bZIP-mediated gene transcription by pregnenolone sulfate. Rather, additional expression of TRPM3 or depolarization of the cells is required to connect pregnenolone sulfate stimulation with enhanced gene transcription.

  18. AP-1 regulates sphingosine kinase 1 expression in a positive feedback manner in glomerular mesangial cells exposed to high glucose.

    PubMed

    Huang, Kaipeng; Huang, Juan; Chen, Cheng; Hao, Jie; Wang, Shaogui; Huang, Junying; Liu, Peiqing; Huang, Heqing

    2014-03-01

    Our previous studies have confirmed that the sphingosine kinase 1 (SphK1)-sphingosine 1-phosphate (S1P) signaling pathway in the kidney under diabetic conditions is closely correlated with the pathogenesis of diabetic nephropathy (DN). The activation of SphK1-S1P pathway by high glucose (HG) can increase the expression of fibronectin (FN), an important fibrotic component, in glomerular mesangial cells (GMCs) by promoting the DNA-binding activity of transcription factor AP-1. However, the mechanism responsible for the sustained activation of SphK1-S1P pathway remains unclear. Given the binding motifs for AP-1 within the first intron of the SphK1 gene, we speculated that the activated AP-1 in the kidney under HG condition possibly regulates SphK1 expression in a positive feedback manner, thereby promoting the sustained activation of SphK1-S1P pathway and mediating the pathological progression of DN. Here, we observed the effect of AP-1 on SphK1 expression in GMCs and explored the molecular mechanism involved in the sustained activation of SphK1-S1P pathway. We found two consensus binding motifs for AP-1 in the promoter sequences and non-coding region downstream of the transcriptional initiation of the rat SphK1 gene by chromatin immunoprecipitation assay. The treatment of GMCs with both HG and S1P significantly increased the protein expression of c-Jun and c-Fos, and obviously enhanced the phosphorylation of c-Jun at Ser63 and Ser73, and c-Fos at Ser32. Knockdown of c-Jun and c-Fos with siRNAs substantially inhibited the expression of SphK1 and FN, whereas overexpression of c-Jun and c-Fos significantly increased the expression of SphK1 and FN. Curcumin treatment greatly decreased the levels of c-Jun, c-Fos, SphK1, and FN in the kidney tissues of diabetic rats. SiRNAs targeting SphK1 and S1P2 receptor respectively inhibited the phosphorylation of c-Jun (ser63 and ser73) and c-Fos (ser32), as well as FN expression under both normal and HG conditions. Our data

  19. Antroquinonol from Antrodia Camphorata suppresses breast tumor migration/invasion through inhibiting ERK-AP-1- and AKT-NF-κB-dependent MMP-9 and epithelial-mesenchymal transition expressions.

    PubMed

    Lee, Wai-Theng; Lee, Tzong-Huei; Cheng, Chia-Hsiung; Chen, Ku-Chung; Chen, Yen-Chou; Lin, Cheng-Wei

    2015-04-01

    Antroquinonol (ANQ) is an ubiquinon derivative isolated from the mycelium of Antrodia camphorata. However, the effect of ANQ on breast cancer treatment is unknown. We found that ANQ significantly suppressed the migration and invasion of breast cancer MDA-MB-231 cells, and inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced invasiveness by MCF7 cells. ANQ inhibiting MMP-9 gene expression and enzymatic activity occurred at transcriptional regulation. Mechanistically, activation of ERK and AKT is crucial for MMP-9 gene expression, and the addition of ANQ suppressed phosphorylation of ERK and AKT. The induction of the AP-1 and NF-κB pathway participated in MMP-9 gene expression. Suppression of ERK inhibited AP-1, whereas blocking AKT diminished NF-κB activity, and treatment with ANQ suppressed both AP-1 and NF-κB signaling. Moreover, ANQ suppressed EMT protein expression, and inhibited TPA-induced EMT through downregulating the ERK-AP-1 and AKT-NF-κB signaling cascades. Together, our data showed for the first time that ANQ inhibited breast cancer invasiveness by suppressing ERK-AP-1- and AKT-NF-κB-dependent MMP-9 and EMT expressions.

  20. Tungsten Carbide-Cobalt Nanoparticles Induce Reactive Oxygen Species, AKT, ERK, AP-1, NF-κB, VEGF, and Angiogenesis.

    PubMed

    Liu, Ling-Zhi; Ding, Min; Zheng, Jenny Z; Zhu, Yingxue; Fenderson, Bruce A; Li, Bingyun; Yu, Jing J; Jiang, Bing-Hua

    2015-07-01

    Powder mixtures of tungsten carbide and metallic cobalt (WC-Co) are widely used in various products. Nanoparticles are engineered structures with at least one dimension of 100 nm or smaller. WC-Co is known to be associated with lung injury and diseases. Angiogenesis is a key process during vasculature, carcinogenesis, recovery of injury, and inflammatory diseases. However, the cellular effects of WC-Co nanoparticles on angiogenesis remain to be elucidated. In this study, we investigated angiogenic response and relative mechanisms after exposure to WC-Co nanoparticles. Our results showed that WC-Co nanoparticles at 5 μg/cm(2) induced ROS production which activated AKT and ERK1/2 signaling pathways in lung epithelial cells by reactive oxygen species (ROS) staining and immunoblotting; WC-Co treatment also increased transcriptional activation of AP-1, NF-κB, and VEGF by reporter assay. Further studies demonstrated that ROS are upstream molecules of AKT and ERK signaling pathways; the activation of AP-1, NF-κB, and VEGF was through ROS generation, AKT and ERK1/2 activation. In addition, WC-Co nanoparticles affected the cells to induce angiogenesis by chicken chorioallantoic membrane (CAM) assay. These results illustrate that exposure to WC-Co nanoparticles induces angiogenic response by activating ROS, AKT, and ERK1/2 signaling pathways and the downstream molecules and elucidate the potential molecular mechanisms during this process. This information may be useful for preventing potential damage from nanoparticle exposure in the future.

  1. Tcra enhancer activation by inducible transcription factors downstream of pre-TCR signaling.

    PubMed

    del Blanco, Beatriz; García-Mariscal, Alberto; Wiest, David L; Hernández-Munain, Cristina

    2012-04-01

    The Tcra enhancer (Eα) is essential for pre-TCR-mediated activation of germline transcription and V(D)J recombination. Eα is considered an archetypical enhanceosome that acts through the functional synergy and cooperative binding of multiple transcription factors. Based on dimethylsulfate genomic footprinting experiments, there has been a long-standing paradox regarding Eα activation in the absence of differences in enhancer occupancy. Our data provide the molecular mechanism of Eα activation and an explanation of this paradox. We found that germline transcriptional activation of Tcra is dependent on constant phospholipase Cγ, as well as calcineurin- and MAPK/ERK-mediated signaling, indicating that inducible transcription factors are crucially involved. NFAT, AP-1, and early growth response factor 1, together with CREB-binding protein/p300 coactivators, bind to Eα as part of an active enhanceosome assembled during pre-TCR signaling. We favor a scenario in which the binding of lymphoid-restricted and constitutive transcription factors to Eα prior to its activation forms a regulatory scaffold to recruit factors induced by pre-TCR signaling. Thus, the combinatorial assembly of tissue- and signal-specific transcription factors dictates the Eα function. This mechanism for enhancer activation may represent a general paradigm in tissue-restricted and stimulus-responsive gene regulation.

  2. Arsenic may be involved in fluoride-induced bone toxicity through PTH/PKA/AP1 signaling pathway.

    PubMed

    Zeng, Qi-bing; Xu, Yu-yan; Yu, Xian; Yang, Jun; Hong, Feng; Zhang, Ai-hua

    2014-01-01

    Chronic exposure to combined fluoride and arsenic continues to be a major public health problem worldwide, affecting thousands of people. In recent years, more and more researchers began to focus on the interaction between the fluorine and the arsenic. In this study, the selected investigation site was located in China. The study group was selected from people living in fluoride-arsenic polluted areas due to burning coal. The total number of participants was 196; including the fluoride-arsenic anomaly group (130) and the fluoride-arsenic normal group (63). By observing the changes in gene and protein expression of PTH/PKA/AP1 signaling pathway, the results show that fluoride can increase the expression levels of PTH, PKA, and AP1, but arsenic can only affect the expression of AP1; fluoride and arsenic have an interaction on the expression of AP1. Further study found that fluoride and arsenic can affect the mRNA expression level of c-fos gene (AP1 family members), and have an interaction on the expression of c-fos, but not c-jun. The results indicate that PTH/PKA/AP1 signaling pathway may play an important role in bone toxicity of fluoride. Arsenic can affect the expression of c-fos, thereby affecting the expression of transcription factor AP1, indirectly involved in fluoride-induced bone toxicity. Copyright © 2013. Published by Elsevier B.V.

  3. Multivalent Targeting Based Delivery of Therapeutic Peptide using AP1-ELP Carrier for Effective Cancer Therapy

    PubMed Central

    Sarangthem, Vijaya; Kim, Yunjae; Singh, Thoudam Debraj; Seo, Bo-Yeon; Cheon, Sun-Ha; Lee, Young-Jin; Lee, Byung-Heon; Park, Rang-Woon

    2016-01-01

    Elastin-like polypeptide (ELP)-based drug delivery has been utilized for various applications including cancer therapies for many years. Genetic incorporation of internalization ligands and cell-targeting peptides along with ELP polymer enhanced tumor accumulation and retention time as well as stability and activities of the drug conjugates. Herein, we described a unique delivery system comprised of genetically engineered ELP incorporated with multiple copies of IL-4 receptor targeting peptide (AP1) periodically and proapoptotic peptide (KLAKLAK)2 referred to as AP1-ELP-KLAK. It triggered thermal-responsive self-assembly into a nanoparticle-like structure at physiological body temperature and stabilized its helical conformation, which is critical for its membrane-disrupting activities. Increased IL-4 receptor specific cellular internalization was associated with the enhanced cytotoxic effect of (KLAKLAK)2 peptide. Additionally, multivalent presentation of targeting ligands by AP1-ELP-KLAK significantly enhanced intratumoral localization and prolonged the retention time compared to ELP-KLAK, non-targeted control. Systemic administration of AP1-ELP-KLAK significantly inhibited tumor growth by provoking cell apoptosis in various tumor xenograft models without any specific organ toxicity. Thus, our newly designed AP1-ELP-KLAK polymer nanoparticle is a promising candidate for effective cancer therapy and due to the simple preparative procedures of ELPs, this platform can be used as a good carrier for tumor-specific delivery of other therapeutics. PMID:27924160

  4. Curcumin attenuates carcinogenesis by down regulating proinflammatory cytokine interleukin-1 (IL-1α and IL-1β) via modulation of AP-1 and NF-IL6 in lymphoma bearing mice.

    PubMed

    Das, Laxmidhar; Vinayak, Manjula

    2014-05-01

    Interleukin-1 (IL-1α and IL-1β) is a prototypic, potent, multifunctional proinflammatory cytokine affecting almost all cell types. Expression of IL-1 is up regulated in different tumor phenotypes and is implicated as an important factor in tumor progression via expression of metastatic, angiogenic genes and growth factors. Therefore, down regulation of expression of IL-1 may be able to inhibit cancer progression. Mechanism of transcriptional regulation of mouse IL-1α is not yet reported. AP-1 binding site at -12 to -6 on human IL-1α promotor is highly conserved in rat IL-1α gene and regulates its expression. Based on in silico analysis, regions -12 to -6bp is found to be conserved in human and mouse IL-1α gene promotor and therefore selected to study activation of IL-1α. Further, the regions -12 to -6bp in mouse IL-1α gene promotor corresponding to AP-1 binding element show 3'→5' orientation, necessary for AP-1 binding. The present work is focused on long term effect of curcumin on expression of IL-1α and IL-1β in liver of lymphoma bearing mice. Transcriptional regulation of IL-1α and IL-1β was analyzed by AP-1 and NF-IL-6 respectively. Elevated expression and protein level of IL-1α and IL-1β were found in lymphoma bearing mice compared to normal, which were significantly down regulated by curcumin treatment. Similarly, curcumin treatment down regulated activation of IL-1α and IL-1β via AP-1 and NF-IL-6 respectively. The findings conclude that curcumin attenuates carcinogenesis by down regulating proinflammatory cytokine interleukin-1 (IL-1α and IL-1β) via modulation of AP-1 and NF-IL6 respectively in lymphoma bearing mice.

  5. n-Butyrate inhibits Jun NH(2)-terminal kinase activation and cytokine transcription in mast cells

    SciTech Connect

    Diakos, Christos; Prieschl, Eva E.; Saeemann, Marcus D.; Boehmig, Georg A.; Csonga, Robert; Sobanov, Yury; Baumruker, Thomas; Zlabinger, Gerhard J. . E-mail: gerhard.zlabinger@meduniwien.ac.at

    2006-10-20

    Mast cells are well known to contribute to type I allergic conditions but only recently have been brought in association with chronic relapsing/remitting autoimmune diseases such as celiac disease and ulcerative colitis. Since the bacterial metabolite n-butyrate is considered to counteract intestinal inflammation we investigated the effects of this short chain fatty acid on mast cell activation. Using RNAse protection assays and reporter gene technology we show that n-butyrate downregulates TNF-{alpha} transcription. This correlates with an impaired activation of the Jun NH(2)-terminal kinase (JNK) but not other MAP kinases such as ERK and p38 that are largely unaffected by n-butyrate. As a consequence, we observed a decreased nuclear activity of AP-1 and NF-AT transcription factors. These results indicate that n-butyrate inhibits critical inflammatory mediators in mast cells by relatively selectively targeting the JNK signalling.

  6. DNA constraints on transcription activation in vitro.

    PubMed

    Ross, E D; Keating, A M; Maher LJ 3RD

    2000-03-24

    Activators of eukaryotic transcription often function over a range of distances. It is commonly hypothesized that the intervening DNA between the transcription start site and the activator binding sites forms a loop in order to allow the activators to interact with the basal transcription apparatus, either directly or through mediators. If this hypothesis is correct, activation should be sensitive to the presence of intrinsic bends in the intervening DNA. Similarly, the precise helical phasing of such DNA bends and of the activator binding sites relative to the basal promoter should affect the degree of transcription activation. To explore these considerations, we designed transcription templates based on the adenovirus E4 promoter supplemented with upstream Gal4 activator binding sites. Surprisingly, we found that neither insertion of intrinsically curved DNA sequences between the activator binding sites and the basal promoter, nor alteration of the relative helical alignment of the activator binding sites and the basal promoter significantly affected in vitro transcription activation in HeLa cell nuclear extract. In all cases, the degree of transcription activation was a simple inverse function of the length of intervening DNA. Possible implications of these unexpected results are discussed. Copyright 2000 Academic Press.

  7. Synergistic transcriptional enhancement does not depend on the number of acidic activation domains bound to the promoter.

    PubMed Central

    Oliviero, S; Struhl, K

    1991-01-01

    Many eukaryotic transcriptional activator proteins contain a DNA-binding domain that interacts with specific promoter sequences and an acidic activation region that is required to stimulate transcription. Transcriptional enhancement by such activator proteins is often synergistic and promiscuous; promoters containing multiple binding sites for an individual protein or even for unrelated proteins can be 10-100 times more active than promoters with single sites. It has been suggested that such synergy reflects a nonlinear response of the basic transcription machinery to the number and/or quality of acidic activation regions. Here, we determine the transcriptional activity of Jun-Fos heterodimers containing one or two GCN4 acidic activation regions on promoters containing one or two Ap-1 target sites. Surprisingly, heterodimers with one or two acidic regions activate transcription with similar efficiency and are equally synergistic (10- to 15-fold) on promoters containing two target sites. Thus, transcriptional synergy does not depend on the number of acidic activation regions but rather on the number of proteins bound to the promoter. This suggests that synergy is mediated either by cooperative DNA binding or by alternative mechanisms in which the DNA-binding domain plays a more direct role in transcription (e.g., changes in DNA structure, nucleosome displacement, or direct interactions with the transcriptional machinery). Images PMID:1898773

  8. A novel c-Jun-dependent signal transduction pathway necessary for the transcriptional activation of interferon gamma response genes.

    PubMed

    Gough, Daniel J; Sabapathy, Kanaga; Ko, Enoch Yi-No; Arthur, Helen A; Schreiber, Robert D; Trapani, Joseph A; Clarke, Christopher J P; Johnstone, Ricky W

    2007-01-12

    The biological effects of interferon gamma (IFNgamma) are mediated by interferon-stimulated genes (ISGs), many of which are activated downstream of Janus kinase (JAK)/signal transducer and activator of transcription 1 (STAT1) signaling. Herein we have shown that IFNgamma rapidly activated AP-1 DNA binding that required c-Jun but was independent of JAK1 and STAT1. IFNgamma-induced c-Jun phosphorylation and AP-1 DNA binding required the MEK1/2 and ERK1/2 signaling pathways, whereas the JNK1/2 and p38 mitogen-activated protein kinase pathways were dispensable. The induction of several ISGs, including ifi-205 and iNOS, was impaired in IFNgamma-treated c-Jun-/- cells, but others, such as IP-10 and SOCS3, were unaffected, and chromatin immunoprecipitation demonstrated that c-Jun binds to the iNOS promoter following treatment with IFNgamma. Thus, IFNgamma induced JAK1- and STAT1-independent activation of the ERK mitogen-activated protein kinase pathway, phosphorylation of c-Jun, and activation of AP-1 DNA binding, which are important for the induction of a subset of ISGs. This represents a novel signal transduction pathway induced by IFNgamma that proceeds in parallel with conventional JAK/STAT signaling to activate ISGs.

  9. Interaction of amphiphysins with AP-1 clathrin adaptors at the membrane.

    PubMed

    Huser, Sonja; Suri, Gregor; Crottet, Pascal; Spiess, Martin

    2013-02-15

    The assembly of clathrin/AP (adaptor protein)-1-coated vesicles on the trans-Golgi network and endosomes is much less studied than that of clathrin/AP-2 vesicles at the plasma membrane for endocytosis. In vitro, the association of AP-1 with protein-free liposomes had been shown to require phosphoinositides, Arf1 (ADP-ribosylation factor 1)-GTP and additional cytosolic factor(s). We have purified an active fraction from brain cytosol and found it to contain amphiphysin 1 and 2 and endophilin A1, three proteins known to be involved in the formation of AP-2/clathrin coats at the plasma membrane. Assays with bacterially expressed and purified proteins showed that AP-1 stabilization on liposomes depends on amphiphysin 2 or the amphiphysin 1/2 heterodimer. Activity is independent of the SH3 (Src homology 3) domain, but requires interaction of the WDLW motif with γ-adaptin. Endogenous amphiphysin in neurons and transfected protein in cell lines co-localize perinuclearly with AP-1 at the trans-Golgi network. This localization depends on interaction of clathrin and the adaptor sequence in the amphiphysins and is sensitive to brefeldin A, which inhibits Arf1-dependent AP-1 recruitment. Interaction between AP-1 and amphiphysin 1/2 in vivo was demonstrated by co-immunoprecipitation after cross-linking. These results suggest an involvement of amphiphysins not only with AP-2 at the plasma membrane, but also in AP-1/clathrin coat formation at the trans-Golgi network.

  10. Activation of the Arabidopsis B class homeotic genes by APETALA1.

    PubMed

    Ng, M; Yanofsky, M F

    2001-04-01

    Proper development of petals and stamens in Arabidopsis flowers requires the activities of APETALA3 (AP3) and PISTILLATA (PI), whose transcripts can be detected in the petal and stamen primordia. Localized expression of AP3 and PI requires the activities of at least three genes: APETALA1 (AP1), LEAFY (LFY), and UNUSUAL FLORAL ORGANS (UFO). It has been proposed that UFO provides spatial cues and that LFY specifies competence for AP3 and PI expression in the developing flower. To understand the epistatic relationship among AP1, LFY, and UFO in regulating AP3 and PI expression, we generated two versions of AP1 that have strong transcriptional activation potential. Genetic and molecular analyses of transgenic plants expressing these activated AP1 proteins show that the endogenous AP1 protein acts largely as a transcriptional activator in vivo and that AP1 specifies petals by regulating the spatial domains of AP3 and PI expression through UFO.

  11. Pb2+ induces gastrin gene expression by extracellular signal-regulated kinases 1/2 and transcription factor activator protein 1 in human gastric carcinoma cells.

    PubMed

    Chan, Chien-Pin; Tsai, Yao-Ting; Chen, Yao-Li; Hsu, Yu-Wen; Tseng, Joseph T; Chuang, Hung-Yi; Shiurba, Robert; Lee, Mei-Hsien; Wang, Jaw-Yuan; Chang, Wei-Chiao

    2015-02-01

    Divalent lead ions (Pb(2+) ) are toxic environmental pollutants known to cause serious health problems in humans and animals. Absorption of Pb(2+) from air, water, and food takes place in the respiratory and digestive tracts. The ways in which absorbed Pb(2+) affects cell physiology are just beginning to be understood at the molecular level. Here, we used reverse transcription PCR and Western blotting to analyze cultures of human gastric carcinoma cells exposed to 10 μM lead nitrate. We found that Pb(2+) induces gastrin hormone gene transcription and translation in a time-dependent manner. Promoter deletion analysis revealed that activator protein 1 (AP1) was necessary for gastrin gene transcription in cells exposed to Pb(2+) . MitogIen-activated protein kinase (MAPK)/ERK kinase inhibitor PD98059 suppressed the Pb(2+) -induced increase in messenger RNA. Epidermal growth factor receptor (EGFR) inhibitors AG1478 and PD153035 reduced both transcription and phosphorylation by extracellular signal-regulated kinase (ERK1/2). Cells exposed to Pb(2+) also increased production of c-Jun protein, a component of AP1, and over-expression of c-Jun enhanced activation of the gastrin promoter. In sum, the findings suggest the EGFR-ERK1/2-AP1 pathway mediates the effects of Pb(2+) on gastrin gene activity in cell culture.

  12. Mitotic Transcriptional Activation: Clearance of Actively Engaged Pol II via Transcriptional Elongation Control in Mitosis.

    PubMed

    Liang, Kaiwei; Woodfin, Ashley R; Slaughter, Brian D; Unruh, Jay R; Box, Andrew C; Rickels, Ryan A; Gao, Xin; Haug, Jeffrey S; Jaspersen, Sue L; Shilatifard, Ali

    2015-11-05

    Although it is established that some general transcription factors are inactivated at mitosis, many details of mitotic transcription inhibition (MTI) and its underlying mechanisms are largely unknown. We have identified mitotic transcriptional activation (MTA) as a key regulatory step to control transcription in mitosis for genes with transcriptionally engaged RNA polymerase II (Pol II) to activate and transcribe until the end of the gene to clear Pol II from mitotic chromatin, followed by global impairment of transcription reinitiation through MTI. Global nascent RNA sequencing and RNA fluorescence in situ hybridization demonstrate the existence of transcriptionally engaged Pol II in early mitosis. Both genetic and chemical inhibition of P-TEFb in mitosis lead to delays in the progression of cell division. Together, our study reveals a mechanism for MTA and MTI whereby transcriptionally engaged Pol II can progress into productive elongation and finish transcription to allow proper cellular division.

  13. Cell entry of bovine ephemeral fever virus requires activation of Src-JNK-AP1 and PI3K-Akt-NF-κB pathways as well as Cox-2-mediated PGE2 /EP receptor signalling to enhance clathrin-mediated virus endocytosis.

    PubMed

    Cheng, Ching-Yuan; Huang, Wei-Ru; Chi, Pei-I; Chiu, Hung-Chuan; Liu, Hung-Jen

    2015-07-01

    Although we have previously demonstrated that cell entry of bovine ephemeral fever virus (BEFV) follows a clathrin-mediated and dynamin 2-dependent endocytosis pathway, the cellular mechanism mediating virus entry remains unknown. Here, we report that BEFV triggers simultaneously Src-JNK-AP1 and PI3K-Akt-NF-κB signalling pathways in the stage of virus binding to induce clathrin and dynamin 2 expressions, while vesicular stomatitis virus only activates Src-JNK signalling to enhance its entry. Activation of these pathways by ultraviolet-inactivated BEFV suggests a role for virus binding but not viral internalization and gene expression. By blocking these signalling pathways with specific inhibitors, BEFV-induced expressions of clathrin and dynamin 2 were significantly diminished. By labelling BEFV with 3,3'-dilinoleyloxacarbocyanine perchlorate to track viral entry, we found that virus entry was hindered by both Src and Akt inhibitors, suggesting that these signalling pathways are crucial for efficient virus entry. In addition, BEFV also triggers Cox-2-catalysed prostaglandin E2 (PGE2) synthesis and induces expressions of G-protein-coupled E-prostanoid (EP) receptors 2 and 4, leading to amplify signal cascades of Src-JNK-AP1 and PI3K-Akt-NF-κB, which elevates both clathrin and dynamin 2 expressions. Furthermore, pretreatment of cells with adenylate cyclase (cAMP) inhibitor SQ22536 reduced BEFV-induced Src phosphorylation as well as clathrin and dynamin 2 expressions. Our findings reveal for the first time that BEFV activates the Cox-2-mediated PGE2/EP receptor signalling pathways, further enhancing Src-JNK-AP1 in a cAMP-dependent manner and PI3K-Akt-NF-κB in a cAMP-independent manner. Accordingly, BEFV stimulates PGE2/EP receptor signalling amplifying Src-JNK-AP1 and PI3K-Akt-NF-κB pathways in an autocrine or paracrine fashion to enhance virus entry. © 2015 John Wiley & Sons Ltd.

  14. Dexamethasone rapidly suppresses IL-33-stimulated mast cell function by blocking transcription factor activity.

    PubMed

    Paranjape, Anuya; Chernushevich, Oksana; Qayum, Amina Abdul; Spence, Andrew J; Taruselli, Marcela T; Abebayehu, Daniel; Barnstein, Brian O; McLeod, Jamie Josephine Avila; Baker, Bianca; Bajaj, Gurjas S; Chumanevich, Alena P; Oskeritzian, Carole A; Ryan, John J

    2016-12-01

    Mast cells are critical effectors of allergic disease and can be activated by IL-33, a proinflammatory member of the IL-1 cytokine family. IL-33 worsens the pathology of mast cell-mediated diseases, but therapies to antagonize IL-33 are still forthcoming. Because steroids are the mainstay of allergic disease treatment and are well known to suppress mast cell activation by other stimuli, we examined the effects of the steroid dexamethasone on IL-33-mediated mast cell function. We found that dexamethasone potently and rapidly suppressed cytokine production elicited by IL-33 from murine bone marrow-derived and peritoneal mast cells. IL-33 enhances IgE-mediated mast cell cytokine production, an activity that was also antagonized by dexamethasone. These effects were consistent in human mast cells. We additionally observed that IL-33 augmented migration of IgE-sensitized mast cells toward antigen. This enhancing effect was similarly reversed by dexamethasone. Simultaneous addition of dexamethasone with IL-33 had no effect on the phosphorylation of MAP kinases or NFκB p65 subunit; however, dexamethasone antagonized AP-1- and NFκB-mediated transcriptional activity. Intraperitoneal administration of dexamethasone completely abrogated IL-33-mediated peritoneal neutrophil recruitment and prevented plasma IL-6 elevation. These data demonstrate that steroid therapy may be an effective means of antagonizing the effects of IL-33 on mast cells in vitro and in vivo, acting partly by suppressing IL-33-induced NFκB and AP-1 activity.

  15. AP1 Factor Inactivation in the Suprabasal Epidermis Causes Increased Epidermal Hyperproliferation and Hyperkeratosis but Reduced Carcinogen-Dependent Tumor Formation

    PubMed Central

    Rorke, Ellen A.; Adhikary, Gautam; Jans, Ralph; Crish, James F.; Eckert, Richard L.

    2010-01-01

    AP1 (jun/fos) factors comprise a family of transcriptional regulators (c-jun, junB, junD, c-fos, FosB, Fra-1 and Fra-2) that are key controllers of epidermal keratinocyte survival and differentiation, and are important drivers of cancer development. Understanding the role of these factors in epidermis is complicated by the fact that each member is expressed in defined cell layers during epidermal differentiation, and because AP1 factors regulate competing processes (i.e., proliferation, apoptosis and differentiation). We have proposed that AP1 factors function differently in basal versus suprabasal epidermis. To test this, we inactivated suprabasal AP1 factor function in mouse epidermis by targeted expression of dominant-negative c-jun (TAM67) which inactivates function of all AP1 factors. This produces increased basal keratinocyte proliferation, delayed differentiation, and extensive hyperkeratosis. These findings contrast with previous studies showing that basal layer AP1 factor inactivation does not perturb resting epidermis. It is interesting that in spite of extensive keratinocyte hyperproliferation, susceptibility to carcinogen-dependent tumor induction is markedly attenuated. These novel observations strongly suggest that AP1 factors have distinct roles in the basal versus suprabasal epidermis, confirm that AP1 factor function is required for normal terminal differentiation, and suggest that AP1 factors play a different role in normal epidermis versus in cancer progression. PMID:20818430

  16. Transcription Factor Interplay between LEAFY and APETALA1/CAULIFLOWER during Floral Initiation.

    PubMed

    Goslin, Kevin; Zheng, Beibei; Serrano-Mislata, Antonio; Rae, Liina; Ryan, Patrick T; Kwaśniewska, Kamila; Thomson, Bennett; Ó'Maoiléidigh, Diarmuid S; Madueño, Francisco; Wellmer, Frank; Graciet, Emmanuelle

    2017-06-01

    The transcription factors LEAFY (LFY) and APETALA1 (AP1), together with the AP1 paralog CAULIFLOWER (CAL), control the onset of flower development in a partially redundant manner. This redundancy is thought to be mediated, at least in part, through the regulation of a shared set of target genes. However, whether these genes are independently or cooperatively regulated by LFY and AP1/CAL is currently unknown. To better understand the regulatory relationship between LFY and AP1/CAL and to obtain deeper insights into the control of floral initiation, we monitored the activity of LFY in the absence of AP1/CAL function. We found that the regulation of several known LFY target genes is unaffected by AP1/CAL perturbation, while others appear to require AP1/CAL activity. Furthermore, we obtained evidence that LFY and AP1/CAL control the expression of some genes in an antagonistic manner. Notably, these include key regulators of floral initiation such as TERMINAL FLOWER1 (TFL1), which had been previously reported to be directly repressed by both LFY and AP1. We show here that TFL1 expression is suppressed by AP1 but promoted by LFY. We further demonstrate that LFY has an inhibitory effect on flower formation in the absence of AP1/CAL activity. We propose that LFY and AP1/CAL act as part of an incoherent feed-forward loop, a network motif where two interconnected pathways or transcription factors act in opposite directions on a target gene, to control the establishment of a stable developmental program for the formation of flowers. © 2017 American Society of Plant Biologists. All Rights Reserved.

  17. HIV-1 Nef hijacks clathrin coats by stabilizing AP-1:Arf1 polygons.

    PubMed

    Shen, Qing-Tao; Ren, Xuefeng; Zhang, Rui; Lee, Il-Hyung; Hurley, James H

    2015-10-23

    The lentiviruses HIV and simian immunodeficiency virus (SIV) subvert intracellular membrane traffic as part of their replication cycle. The lentiviral Nef protein helps viruses evade innate and adaptive immune defenses by hijacking the adaptor protein 1 (AP-1) and AP-2 clathrin adaptors. We found that HIV-1 Nef and the guanosine triphosphatase Arf1 induced trimerization and activation of AP-1. Here we report the cryo-electron microscopy structures of the Nef- and Arf1-bound AP-1 trimer in the active and inactive states. A central nucleus of three Arf1 molecules organizes the trimers. We combined the open trimer with a known dimer structure and thus predicted a hexagonal assembly with inner and outer faces that bind the membranes and clathrin, respectively. Hexagons were directly visualized and the model validated by reconstituting clathrin cage assembly. Arf1 and Nef thus play interconnected roles in allosteric activation, cargo recruitment, and coat assembly, revealing an unexpectedly intricate organization of the inner AP-1 layer of the clathrin coat.

  18. Chromatin insulation by a transcriptional activator

    PubMed Central

    Sutter, Nathan B.; Scalzo, David; Fiering, Steven; Groudine, Mark; Martin, David I. K.

    2003-01-01

    In eukaryotic genomes, transcriptionally active regions are interspersed with silent chromatin that may repress genes in its vicinity. Chromatin insulators are elements that can shield a locus from repressive effects of flanking chromatin. Few such elements have been characterized in higher eukaryotes, but transcriptional activating elements are an invariant feature of active loci and have been shown to suppress transgene silencing. Hence, we have assessed the ability of a transcriptional activator to cause chromatin insulation, i.e., to relieve position effects at transgene integration sites in cultured cells. The transgene contained a series of binding sites for the metal-inducible transcriptional activator MTF, linked to a GFP reporter. Clones carrying single integrated transgenes were derived without selection for expression, and in most clones the transgene was silent. Induction of MTF resulted in transition of the transgene from the silent to the active state, prolongation of the active state, and a marked narrowing of the range of expression levels at different genomic sites. At one genomic site, prolonged induction of MTF resulted in suppression of transgene silencing that persisted after withdrawal of the induction stimulus. These results are consistent with MTF acting as a chromatin insulator and imply that transcriptional activating elements can insulate active loci against chromatin repression. PMID:12547916

  19. Novel tumor growth inhibition mechanism by cell cycle regulator cdk2ap1 involves anti-angiogenesis modulation

    PubMed Central

    Zolochevska, Olga; Figueiredo, Marxa L.

    2010-01-01

    We evaluated the effect of expressing the cell cycle regulator protein cdk2-associating protein1 (cdk2ap1) in inhibiting growth of squamous cell carcinoma (SCC). Expression of cdk2ap1 correlated with reduction in several SCC malignant cell phenotypes, including reduced angiogenesis. We observed several alterations in gene expression consistent with classical functions of cdk2ap1, including upregulation of cell cycle inhibitory genes, and an upregulation in expression of genes belonging to both intrinsic and extrinsic apoptotic cascades. Interestingly, we also uncovered a profile of gene expression and activation of signaling pathways that may suggest new tumor-suppressive functions for cdk2ap1 through downregulation of invasion/metastasis and modulation of antiangiogenesis by upregulation of the TGFβ signaling pathway. Blocking of the TGFβ1 pathway resulted in inhibition of the cdk2ap1 antiangiogenesis phenotype. In combination, these data support the role of cdk2ap1 as a tumor suppressor gene that can regulate SCC tumor growth in a cell autonomous manner through decreases in invasiveness and a non cell-autonomous manner through decreases in angiogenesis phenotypes, and these are novel phenotypes induced by cdk2ap1. PMID:20541561

  20. Cloning and transcriptional activity analysis of the porcine cofilin 2 gene promoter.

    PubMed

    Wang, Jia-Mei; Lang, Bin; Zhu, Hong-yan; Du, Hai-ting; Tian, Yu-min; Su, Yu-hong

    2014-09-01

    Cofilins (CFL), including CFL1 and CFL2, are members of the family of actin-binding proteins in eukaryote. CFL2 is predominantly expressed in mammalian skeletal muscle and heart and is important to muscle fiber formation and muscular regeneration. To study transcriptional regulation of porcine CFL2, a 2.5 kb upstream sequence starting from the major CFL2 transcriptional start site was cloned by genome walking. Twelve DNA fragments of the 5' flank region of the porcine CFL2 gene were further isolated from porcine genomic DNA via PCR and inserted into the luciferase reporter vector pGL4.10 to make 12 CFL2 reporter constructs. All reporter vectors were transfected into C2C12, NIH3T3, or Hela cells and their relative luciferase activity measured after 48 h, respectively. Bioinformatics analysis suggested that there were two TATA-boxes at the -508 bp and -453 bp, as well as a GC-box and a CAAT-box in this sequence. Additional transcription factor binding sites including SP1, AP1, AP2, and GATA-1 sites were also predicted. The transcriptional activity of pGL4.10-1554 (1502 bp to +51 bp) was the strongest, and the promoter's active region was mapped to a region from -1502 bp to -1317 bp. Our data provide a foundation for future studies into transcriptional regulation of CFL2.

  1. Chrysin Inhibits Tumor Promoter-Induced MMP-9 Expression by Blocking AP-1 via Suppression of ERK and JNK Pathways in Gastric Cancer Cells

    PubMed Central

    Xia, Yong; Lian, Sen; Khoi, Pham Ngoc; Yoon, Hyun Joong; Joo, Young Eun; Chay, Kee Oh; Kim, Kyung Keun; Do Jung, Young

    2015-01-01

    Cell invasion is a crucial mechanism of cancer metastasis and malignancy. Matrix metalloproteinase-9 (MMP-9) is an important proteolytic enzyme involved in the cancer cell invasion process. High expression levels of MMP-9 in gastric cancer positively correlate with tumor aggressiveness and have a significant negative correlation with patients’ survival times. Recently, mechanisms suppressing MMP-9 by phytochemicals have become increasingly investigated. Chrysin, a naturally occurring chemical in plants, has been reported to suppress tumor metastasis. However, the effects of chrysin on MMP-9 expression in gastric cancer have not been well studied. In the present study, we tested the effects of chrysin on MMP-9 expression in gastric cancer cells, and determined its underlying mechanism. We examined the effects of chrysin on MMP-9 expression and activity via RT-PCR, zymography, promoter study, and western blotting in human gastric cancer AGS cells. Chrysin inhibited phorbol-12-myristate 13-acetate (PMA)-induced MMP-9 expression in a dose-dependent manner. Using AP-1 decoy oligodeoxynucleotides, we confirmed that AP-1 was the crucial transcriptional factor for MMP-9 expression. Chrysin blocked AP-1 via suppression of the phosphorylation of c-Jun and c-Fos through blocking the JNK1/2 and ERK1/2 pathways. Furthermore, AGS cells pretreated with PMA showed markedly enhanced invasiveness, which was partially abrogated by chrysin and MMP-9 antibody. Our results suggest that chrysin may exert at least part of its anticancer effect by controlling MMP-9 expression through suppression of AP-1 activity via a block of the JNK1/2 and ERK1/2 signaling pathways in gastric cancer AGS cells. PMID:25875631

  2. Chrysin inhibits tumor promoter-induced MMP-9 expression by blocking AP-1 via suppression of ERK and JNK pathways in gastric cancer cells.

    PubMed

    Xia, Yong; Lian, Sen; Khoi, Pham Ngoc; Yoon, Hyun Joong; Joo, Young Eun; Chay, Kee Oh; Kim, Kyung Keun; Do Jung, Young

    2015-01-01

    Cell invasion is a crucial mechanism of cancer metastasis and malignancy. Matrix metalloproteinase-9 (MMP-9) is an important proteolytic enzyme involved in the cancer cell invasion process. High expression levels of MMP-9 in gastric cancer positively correlate with tumor aggressiveness and have a significant negative correlation with patients' survival times. Recently, mechanisms suppressing MMP-9 by phytochemicals have become increasingly investigated. Chrysin, a naturally occurring chemical in plants, has been reported to suppress tumor metastasis. However, the effects of chrysin on MMP-9 expression in gastric cancer have not been well studied. In the present study, we tested the effects of chrysin on MMP-9 expression in gastric cancer cells, and determined its underlying mechanism. We examined the effects of chrysin on MMP-9 expression and activity via RT-PCR, zymography, promoter study, and western blotting in human gastric cancer AGS cells. Chrysin inhibited phorbol-12-myristate 13-acetate (PMA)-induced MMP-9 expression in a dose-dependent manner. Using AP-1 decoy oligodeoxynucleotides, we confirmed that AP-1 was the crucial transcriptional factor for MMP-9 expression. Chrysin blocked AP-1 via suppression of the phosphorylation of c-Jun and c-Fos through blocking the JNK1/2 and ERK1/2 pathways. Furthermore, AGS cells pretreated with PMA showed markedly enhanced invasiveness, which was partially abrogated by chrysin and MMP-9 antibody. Our results suggest that chrysin may exert at least part of its anticancer effect by controlling MMP-9 expression through suppression of AP-1 activity via a block of the JNK1/2 and ERK1/2 signaling pathways in gastric cancer AGS cells.

  3. Possible role of lipid peroxidation in the induction of NF-kappa B and AP-1 in RFL-6 cells by crocidolite asbestos: evidence following protection by vitamin E.

    PubMed

    Faux, S P; Howden, P J

    1997-09-01

    Asbestos fibers cause persistent induction of the oxidative stress sensitive transcription factors nuclear factor kappa-B (NF-kappa B) and activator protein-1 (AP-1) in mammalian cells. These transcription factors play an important role in the regulation of cellular activity. Lipid peroxidation, mediated by reactive oxygen species, is thought to be a possible mechanism in the pathogenicity of asbestos fibers. These studies were designed to determine if crocidolite asbestos-induced lipid peroxidation plays a role in the mechanism of formation of NF-kappa B and AP-1. Treatment of a rat lung fibroblast cell line (RFL-6) with crocidolite asbestos in the presence and absence of the membrane antioxidant vitamin E decreased the levels of crocidolite-induced AP-1 and NF-kappa B to background levels. Preincubation of RFL-6 cells with 5,8,11,14-eicosatetraynoic acid, an inhibitor of arachidonic acid metabolism, prior to exposure to crocidolite, abrogated crocidolite-induced NF-kappa B DNA-binding activity to background levels. Coincubation with indomethacin, a cyclooxygenase inhibitor, had no effect on NF-kappa B DNA-binding activity induced by crocidolite. However, nordihydroguaiaretic acid, a lipoxygenase inhibitor, decreased levels of NF-kappa B to background levels. This would suggest that lipoxygenase metabolites of arachidonic acid, produced following lipid peroxidation, are involved in the cellular signalling events to NF-kappa B transcription factor induction by asbestos.

  4. Targeting activator protein 1 signaling pathway by bioactive natural agents: Possible therapeutic strategy for cancer prevention and intervention.

    PubMed

    Tewari, Devesh; Nabavi, Seyed Fazel; Nabavi, Seyed Mohammad; Sureda, Antoni; Farooqi, Ammad Ahmad; Atanasov, Atanas G; Vacca, Rosa Anna; Sethi, Gautam; Bishayee, Anupam

    2017-09-23

    Activator protein 1 (AP-1) is a key transcription factor in the control of several cellular processes responsible for cell survival proliferation and differentiation. Dysfunctional AP-1 expression and activity are involved in several severe diseases, especially inflammatory disorders and cancer. Therefore, targeting AP-1 has recently emerged as an attractive therapeutic strategy for cancer prevention and therapy. This review summarizes our current understanding of AP-1 biology and function as well as explores and discusses several natural bioactive compounds modulating AP-1-associated signaling pathways for cancer prevention and intervention. Current limitations, challenges, and future directions of research are also critically discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Involvement of Blimp-1 and AP-1 Dysregulation in the 2,3,7,8-Tetrachlorodibenzo-p-dioxin–mediated Suppression of the IgM Response by B Cells

    PubMed Central

    Schneider, Dina; Manzan, Maria A.; Yoo, Byung Sun; Crawford, Robert B.; Kaminski, Norbert

    2009-01-01

    B cell differentiation and humoral immune responses are markedly suppressed by the persistent environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The suppression of humoral immune responses by TCDD occurs by direct actions on the B cell and involves activation of the aryl hydrocarbon receptor. Transcriptional regulation of paired box gene 5 (Pax5), an important regulator of B cell differentiation, is altered by TCDD in concordance with the suppression of B cell differentiation and humoral immunoglobulin M response. We hypothesized that TCDD treatment leads to dysregulation of Pax5 transcription by interfering with the basic B cell differentiation mechanisms and aimed to determine the effects of TCDD on upstream regulators of Pax5. A critical regulator of B cell differentiation, B lymphocyte–induced maturation protein-1 (Blimp-1) acts as a transcriptional repressor of Pax5. In lipopolysaccharide (LPS)-activated murine B cell lymphoma, CH12.LX, Blimp-1 messenger RNA, and DNA-binding activity within the Pax5 promoter were suppressed by TCDD. Furthermore, LPS activation of CH12.LX cells upregulated DNA-binding activity of activator protein 1 (AP-1) at three responsive element–like motifs within the Blimp-1 promoter. TCDD treatment of LPS-activated CH12.LX cells suppressed AP-1 binding to these motifs between 24 and 72 h, in concordance with the suppression of Blimp-1 by TCDD. A more comprehensive analysis at 72 h demonstrated that the suppression of AP-1 binding within the Blimp-1 promoter by TCDD was concentration dependent. In summary, our findings link the TCDD-mediated suppression of Blimp-1 through AP-1 to the dysregulation of Pax5, which ultimately leads to the suppression of B cell differentiation and humoral immune responses. PMID:19237549

  6. Involvement of Blimp-1 and AP-1 dysregulation in the 2,3,7,8-Tetrachlorodibenzo-p-dioxin-mediated suppression of the IgM response by B cells.

    PubMed

    Schneider, Dina; Manzan, Maria A; Yoo, Byung Sun; Crawford, Robert B; Kaminski, Norbert

    2009-04-01

    B cell differentiation and humoral immune responses are markedly suppressed by the persistent environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The suppression of humoral immune responses by TCDD occurs by direct actions on the B cell and involves activation of the aryl hydrocarbon receptor. Transcriptional regulation of paired box gene 5 (Pax5), an important regulator of B cell differentiation, is altered by TCDD in concordance with the suppression of B cell differentiation and humoral immunoglobulin M response. We hypothesized that TCDD treatment leads to dysregulation of Pax5 transcription by interfering with the basic B cell differentiation mechanisms and aimed to determine the effects of TCDD on upstream regulators of Pax5. A critical regulator of B cell differentiation, B lymphocyte-induced maturation protein-1 (Blimp-1) acts as a transcriptional repressor of Pax5. In lipopolysaccharide (LPS)-activated murine B cell lymphoma, CH12.LX, Blimp-1 messenger RNA, and DNA-binding activity within the Pax5 promoter were suppressed by TCDD. Furthermore, LPS activation of CH12.LX cells upregulated DNA-binding activity of activator protein 1 (AP-1) at three responsive element-like motifs within the Blimp-1 promoter. TCDD treatment of LPS-activated CH12.LX cells suppressed AP-1 binding to these motifs between 24 and 72 h, in concordance with the suppression of Blimp-1 by TCDD. A more comprehensive analysis at 72 h demonstrated that the suppression of AP-1 binding within the Blimp-1 promoter by TCDD was concentration dependent. In summary, our findings link the TCDD-mediated suppression of Blimp-1 through AP-1 to the dysregulation of Pax5, which ultimately leads to the suppression of B cell differentiation and humoral immune responses.

  7. Transcriptional regulation by post-transcriptional modification--role of phosphorylation in Sp1 transcriptional activity.

    PubMed

    Chu, Shijian

    2012-10-15

    Sp1 is a ubiquitously expressed transcription factor involved in the regulation of a large number of genes including housekeeping genes as well as actively regulated genes. Although Sp1 was discovered nearly three decades ago, its functional diversity is still not completely understood. One of the ways that make Sp1 versatile in transcriptional regulation is its post-transcriptional modification, which alters Sp1 structure in different cells and at different times. Compared to other types of modifications of the Sp1 protein, phosphorylation has been studied far more extensively. This review focuses on the inducers, pathways, enzymes, and biological effects of Sp1 phosphorylation. Recent data are beginning to reveal the biological significance and universal presence of Sp1 phosphorylation-related cell/molecular responses. Studies in this field provide a quick glance at how a simple chemical modification of a transcription factor could produce significant functional diversity of the protein.

  8. Luteolin and luteolin-7-O-glucoside inhibit lipopolysaccharide-induced inflammatory responses through modulation of NF-κB/AP-1/PI3K-Akt signaling cascades in RAW 264.7 cells

    PubMed Central

    Park, Chung Mu

    2013-01-01

    Luteolin is a flavonoid found in abundance in celery, green pepper, and dandelions. Previous studies have shown that luteolin is an anti-inflammatory and anti-oxidative agent. In this study, the anti-inflammatory capacity of luteolin and one of its glycosidic forms, luteolin-7-O-glucoside, were compared and their molecular mechanisms of action were analyzed. In lipopolysaccharide (LPS)-activated RAW 264.7 cells, luteolin more potently inhibited the production of nitric oxide (NO) and prostaglandin E2 as well as the expression of their corresponding enzymes (inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) than luteolin-7-O-glucoside. The molecular mechanisms underlying these effects were investigated to determine whether the inflammatory response was related to the transcription factors, nuclear factor (NF)-κB and activator protein (AP)-1, or their upstream signaling molecules, mitogen-activated protein kinases (MAPKs) and phosphoinositide 3-kinase (PI3K). Luteolin attenuated the activation of both transcription factors, NF-κB and AP-1, while luteolin-7-O-glucoside only impeded NF-κB activation. However, both flavonoids inhibited Akt phosphorylation in a dose-dependent manner. Consequently, luteolin more potently ameliorated LPS-induced inflammation than luteolin-7-O-glucoside, which might be attributed to the differentially activated NF-κB/AP-1/PI3K-Akt pathway in RAW 264.7 cells. PMID:24353826

  9. Luteolin and luteolin-7-O-glucoside inhibit lipopolysaccharide-induced inflammatory responses through modulation of NF-κB/AP-1/PI3K-Akt signaling cascades in RAW 264.7 cells.

    PubMed

    Park, Chung Mu; Song, Young-Sun

    2013-12-01

    Luteolin is a flavonoid found in abundance in celery, green pepper, and dandelions. Previous studies have shown that luteolin is an anti-inflammatory and anti-oxidative agent. In this study, the anti-inflammatory capacity of luteolin and one of its glycosidic forms, luteolin-7-O-glucoside, were compared and their molecular mechanisms of action were analyzed. In lipopolysaccharide (LPS)-activated RAW 264.7 cells, luteolin more potently inhibited the production of nitric oxide (NO) and prostaglandin E2 as well as the expression of their corresponding enzymes (inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) than luteolin-7-O-glucoside. The molecular mechanisms underlying these effects were investigated to determine whether the inflammatory response was related to the transcription factors, nuclear factor (NF)-κB and activator protein (AP)-1, or their upstream signaling molecules, mitogen-activated protein kinases (MAPKs) and phosphoinositide 3-kinase (PI3K). Luteolin attenuated the activation of both transcription factors, NF-κB and AP-1, while luteolin-7-O-glucoside only impeded NF-κB activation. However, both flavonoids inhibited Akt phosphorylation in a dose-dependent manner. Consequently, luteolin more potently ameliorated LPS-induced inflammation than luteolin-7-O-glucoside, which might be attributed to the differentially activated NF-κB/AP-1/PI3K-Akt pathway in RAW 264.7 cells.

  10. Co-expression analysis identifies CRC and AP1 the regulator of Arabidopsis fatty acid biosynthesis.

    PubMed

    Han, Xinxin; Yin, Linlin; Xue, Hongwei

    2012-07-01

    Fatty acids (FAs) play crucial rules in signal transduction and plant development, however, the regulation of FA metabolism is still poorly understood. To study the relevant regulatory network, fifty-eight FA biosynthesis genes including de novo synthases, desaturases and elongases were selected as "guide genes" to construct the co-expression network. Calculation of the correlation between all Arabidopsis thaliana (L.) genes with each guide gene by Arabidopsis co-expression dating mining tools (ACT) identifies 797 candidate FA-correlated genes. Gene ontology (GO) analysis of these co-expressed genes showed they are tightly correlated to photosynthesis and carbohydrate metabolism, and function in many processes. Interestingly, 63 transcription factors (TFs) were identified as candidate FA biosynthesis regulators and 8 TF families are enriched. Two TF genes, CRC and AP1, both correlating with 8 FA guide genes, were further characterized. Analyses of the ap1 and crc mutant showed the altered total FA composition of mature seeds. The contents of palmitoleic acid, stearic acid, arachidic acid and eicosadienoic acid are decreased, whereas that of oleic acid is increased in ap1 and crc seeds, which is consistent with the qRT-PCR analysis revealing the suppressed expression of the corresponding guide genes. In addition, yeast one-hybrid analysis and electrophoretic mobility shift assay (EMSA) revealed that CRC can bind to the promoter regions of KCS7 and KCS15, indicating that CRC may directly regulate FA biosynthesis. © 2012 Institute of Botany, Chinese Academy of Sciences.

  11. SKF-82958 is a subtype-selective estrogen receptor-alpha (ERalpha ) agonist that induces functional interactions between ERalpha and AP-1.

    PubMed

    Walters, Marian R; Dutertre, Martin; Smith, Carolyn L

    2002-01-18

    The transcriptional activity of estrogen receptors (ERs) can be regulated by ligands as well as agents such as dopamine, which stimulate intracellular signaling pathways able to communicate with these receptors. We examined the ability of SKF-82958 (SKF), a previously characterized full dopamine D1 receptor agonist, to stimulate the transcriptional activity of ERalpha and ERbeta. Treatment of HeLa cells with SKF-82958 stimulated robust ERalpha-dependent transcription from an estrogen-response element-E1b-CAT reporter in the absence of estrogen, and this was accompanied by increased receptor phosphorylation. However, induction of ERbeta-directed gene expression under the same conditions was negligible. In our cell model, SKF treatment did not elevate cAMP levels nor enhance transcription from a cAMP-response element-linked reporter. Control studies revealed that SKF-82958, but not dopamine, competes with 17beta-estradiol for binding to ERalpha or ERbeta with comparable relative binding affinities. Therefore, SKF-82958 is an ERalpha-selective agonist. Transcriptional activation of ERalpha by SKF was more potent than expected from its relative binding activity, and further examination revealed that this synthetic compound induced expression of an AP-1 target gene in a tetradecanoylphorbol-13-acetate-response element (TRE)-dependent manner. A putative TRE site upstream of the estrogen-response element and the amino-terminal domain of the receptor contributed to, but were not required for, SKF-induced expression of an ERalpha-dependent reporter gene. Overexpression of the AP-1 protein c-Jun, but not c-Fos, strongly enhanced SKF-induced ERalpha target gene expression but only when the TRE was present. These studies provide information on the ability of a ligand that weakly stimulates ERalpha to yield strong stimulation of ERalpha-dependent gene expression through cross-talk with other intracellular signaling pathways producing a robust combinatorial response within the

  12. Caffeic acid phenethyl ester inhibits T-cell activation by targeting both nuclear factor of activated T-cells and NF-kappaB transcription factors.

    PubMed

    Márquez, Nieves; Sancho, Rocío; Macho, Antonio; Calzado, Marco A; Fiebich, Bernd L; Muñoz, Eduardo

    2004-03-01

    Caffeic acid phenethyl ester (CAPE), which is derived from the propolis of honeybee hives, has been shown to reveal anti-inflammatory properties. Since T-cells play a key role in the onset of several inflammatory diseases, we have evaluated the immunosuppressive activity of CAPE in human T-cells, discovering that this phenolic compound is a potent inhibitor of early and late events in T-cell receptor-mediated T-cell activation. Moreover, we found that CAPE specifically inhibited both interleukin (IL)-2 gene transcription and IL-2 synthesis in stimulated T-cells. To further characterize the inhibitory mechanisms of CAPE at the transcriptional level, we examined the DNA binding and transcriptional activities of nuclear factor (NF)-kappaB, nuclear factor of activated cells (NFAT), and activator protein-1 (AP-1) transcription factors in Jurkat cells. We found that CAPE inhibited NF-kappaB-dependent transcriptional activity without affecting the degradation of the cytoplasmic NF-kappaB inhibitory protein, IkappaBalpha. However, both NF-kappaB binding to DNA and transcriptional activity of a Gal4-p65 hybrid protein were clearly prevented in CAPE-treated Jurkat cells. Moreover, CAPE inhibited both the DNA-binding and transcriptional activity of NFAT, a result that correlated with its ability to inhibit phorbol 12-myristate 13-acetate plus ionomycin-induced NFAT1 dephosphorylation. These findings provide new insights into the molecular mechanisms involved in the immunomodulatory and anti-inflammatory activities of this natural compound.

  13. Determinants of half-site spacing preferences that distinguish AP-1 and ATF/CREB bZIP domains.

    PubMed Central

    Kim, J; Struhl, K

    1995-01-01

    The AP-1 and ATF/CREB families of eukaryotic transcription factors are dimeric DNA-binding proteins that contain the bZIP structural motif. The AP-1 and ATF/CREB proteins are structurally related and recognize identical half-sites (TGAC), but they differ in their requirements for half-site spacing. AP-1 proteins such as yeast GCN4 preferentially bind to sequences with overlapping half-sites, whereas ATF/CREB proteins bind exclusively to sequences with adjacent half-sites. Here we investigate the distinctions between AP-1 and ATF/CREB proteins by determining the DNA-binding properties of mutant and hybrid proteins. First, analysis of GCN4-ATF1 hybrid proteins indicates that a short surface spanning the basic and fork regions of the bZIP domain is the major determinant of half-site spacing. Replacement of two GCN4 residues on this surface (Ala244 and Leu247) by their ATF1 counterparts largely converts GCN4 into a protein with ATF/CREB specificity. Secondly, analysis of a Fos derivative containing the GCN4 leucine zipper indicates that Fos represents a novel intermediate between AP-1 and ATF/CREB proteins. Thirdly, we examine the effects of mutations in the invariant arginine residue of GCN4 (Arg243) that contacts the central base pair(s) of the target sites. While most mutations abolish DNA binding, substitution of a histidine residue results in a GCN4 derivative with ATF/CREB binding specificity. These results suggest that the AP-1 and ATF/CREB proteins differ in positioning a short surface that includes the invariant arginine and that AP-1 proteins may represent a subclass (and perhaps evolutionary offshoot) of ATF/CREB proteins that can tolerate overlapping half-sites. Images PMID:7630732

  14. Highly efficient gene silencing using perfect complementary artificial miRNA targeting AP1 or heteromeric artificial miRNA targeting AP1 and CAL genes

    PubMed Central

    Park, Wonkeun; Zhai, Jixian; Lee, Jung-Youn

    2009-01-01

    Gene silencing is a useful technique for elucidating biological function of genes by knocking down their expression. A recently developed artificial microRNAs (amiRNAs) exploits an endogenous gene silencing mechanism that processes natural miRNA precursors to small silencing RNAs that target transcripts for degradation. Based on natural miRNA structures, amiRNAs are commonly designed such that they have a few mismatching nucleotides with respect to their target sites as well as within mature amiRNA duplexes. In this study, we performed an analysis in which the conventional and modified form of an amiRNA was compared side by side. We showed that the amiRNA containing 5′ mismatch with its amiRNA* and perfect complementarity to its target gene acted as a highly potent gene silencing agent against AP1, achieving a desired null mutation effect. In addition, a simultaneous silencing of two independent genes, AP1 and CAL1 wastested by employing a multimeric form of amiRNAs. Advantages and potential disadvantages of using amiRNAs with perfect complementarity to the target gene are discussed. The results presented here should be helpful in designing more specific and effective gene silencing agents. PMID:19066901

  15. Highly efficient gene silencing using perfect complementary artificial miRNA targeting AP1 or heteromeric artificial miRNA targeting AP1 and CAL genes.

    PubMed

    Park, Wonkeun; Zhai, Jixian; Lee, Jung-Youn

    2009-03-01

    Gene silencing is a useful technique for elucidating biological function of genes by knocking down their expression. Recently developed artificial microRNAs (amiRNAs) exploit an endogenous gene silencing mechanism that processes natural miRNA precursors to small silencing RNAs that target transcripts for degradation. Based on natural miRNA structures, amiRNAs are commonly designed such that they have a few mismatching nucleotides with respect to their target sites as well as within mature amiRNA duplexes. In this study, we performed an analysis in which the conventional and modified form of an amiRNA was compared side by side. We showed that the amiRNA containing 5' mismatch with its amiRNA* and perfect complementarity to its target gene acted as a highly potent gene silencing agent against AP1, achieving a desired null mutation effect. In addition, a simultaneous silencing of two independent genes, AP1 and CAL1 was tested by employing a multimeric form of amiRNAs. Advantages and potential disadvantages of using amiRNAs with perfect complementarity to the target gene are discussed. The results presented here should be helpful in designing more specific and effective gene silencing agents.

  16. c-Fos-activated synthesis of nuclear phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P₂] promotes global transcriptional changes.

    PubMed

    Ferrero, Gabriel O; Renner, Marianne L; Gil, Germán A; Rodríguez-Berdini, Lucia; Caputto, Beatriz L

    2014-08-01

    c-Fos is a well-recognized member of the AP-1 (activator protein-1) family of transcription factors. In addition to this canonical activity, we previously showed that cytoplasmic c-Fos activates phospholipid synthesis through a mechanism independent of its genomic AP-1 activity. c-Fos associates with particular enzymes of the lipid synthesis pathway at the endoplasmic reticulum and increases the Vmax of the reactions without modifying the Km values. This lipid synthesis activation is associated with events of differentiation and proliferation that require high rates of membrane biogenesis. Since lipid synthesis also occurs in the nucleus, and different phospholipids have been assigned transcription regulatory functions, in the present study we examine if c-Fos also acts as a regulator of phospholipid synthesis in the nucleus. Furthermore, we examine if c-Fos modulates transcription through its phospholipid synthesis activator capacity. We show that nuclear-localized c-Fos associates with and activates PI4P5K (phosphatidylinositol-4-monophosphate 5-kinase), but not with PI4KIIIβ (type IIIβ phosphatidylinositol 4-kinase) thus promoting PtdIns(4,5)P₂ (phosphatidylinositol 4,5-bisphosphate) formation, which, in turn, promotes transcriptional changes. We propose c-Fos as a key regulator of nuclear PtdIns(4,5)P₂ synthesis in response to growth signals that results in c-Fos-dependent transcriptional changes promoted by the newly synthesized lipids.

  17. Molecular basis for designing selective modulators of retinoic acid receptor transcriptional activities.

    PubMed

    Lefebvre, P

    2001-08-01

    Retinoic acid receptors are ligand-regulated transcription factors belonging to the nuclear receptor superfamily, which comprises 49 members in the human genome. all-trans retinoic acid and 9-cis retinoic acid receptors (RARs and RXRs) are each encoded by three distinct genes and several isoforms arise from alternative splicing and the use of different promoters. While RXRs are promiscuous dimerization partners of several other nuclear receptors, RARs are active, in-vivo, when associated to RXRs. Retinoids are therefore regulators of multiple physiological processes, from embryogenesis to metabolism. Different combinations of RXR:RAR heterodimers occur as a function of their tissue-specific expression and their activity is mostly conditioned by the activation status of RAR. These heterodimers are defined as non permissive heterodimers, in opposition to permissive dimers whose transcriptional activity may be modulated through RXR and its dimerization partner. The transcriptional activity of these dimers also relies on their ability to recruit nuclear coactivators and corepressors, which function as multi proteic complexes harboring several enzymatic activities (acetylases, kinases). The structure of the ligand bound to the RAR moiety of the dimer, as well as the nature of the DNA sequence to which dimers are bound, dictate the relative affinity of dimers for coactivators and thus its overall transcriptional activity. RARs are also able to repress the activity of unrelated transcription factors such as AP1 and NF-kappa-B, and therefore have potent anti proliferative and anti inflammatory properties. This review summarizes our current view of molecular mechanisms governing these various activities and emphasizes the need for a detailed understanding of how retinoids may dictate transactivating and transrepressive properties of RARs and RXRs, which may be considered as highly valuable therapeutic targets in many diseases such as cancer, skin hyperproliferation and

  18. Effects of Cigarette Smoke on the Activation of Oxidative Stress-Related Transcription Factors in Female A/J Mouse Lung

    PubMed Central

    Tharappel, Job C.; Cholewa, Jill; Espandiari, Parvaneh; Spear, Brett T.; Gairola, C. Gary; Glauert, Howard P.

    2010-01-01

    Cigarette smoke contains a high concentration of free radicals and induces oxidative stress in the lung and other tissues. Several transcription factors are known to be activated by oxidative stress, including nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and hypoxia-inducible factor (HIF). Studies were therefore undertaken to examine if cigarette smoke could activate these transcription factors, as well as other transcription factors that may be important in lung carcinogenesis. Female A/J mice were exposed to cigarette smoke for 2, 5, 10, 15, 20, 42, or 56 days (6 hr/day, 5 days/wk). Cigarette smoke did not increase NF-κB activation at any of these times, but NF-κB DNA binding activity was lower after 15 days and 56 days of smoke exposure. The DNA binding activity of AP-1 was lower after 10 days and 56 days but was not changed after 42 days of smoke exposure. The DNA binding activity of HIF was quantitatively increased after 42 days of smoke exposure but decreased after 56 days. Whether the activation of other transcription factors in the lung could be altered after exposure to cigarette smoke was subsequently examined. The DNA binding activities of FoxF2, myc-CF1, RORE, and p53 were examined after 10 days of smoke exposure. The DNA binding activities of FoxF2 and p53 were quantitatively increased, but those of myc-CF1 and RORE were unaffected. These studies show that cigarette smoke exposure leads to quantitative increases in DNA binding activities of FoxF2 and p53, while the activations of NF-κB, AP-1, and HIF are largely unaffected or reduced. PMID:20711931

  19. Radiolabeled anti-tissue factor antibody (AP-1) for imaging thrombotic disease by PET

    SciTech Connect

    Joshi, V.; Meinken, G.; Srivastava, S.

    1995-05-01

    The objective of this study was to develop and test radioimmunoconjugates of AP-1, an anti-tissue factor (TF) MAb, for PET imaging of vessel wall injury or associated thrombotic disease. Recently, anti rabbit MAb AP-1 was shown to prevent thrombosis following vascular injury in a rabbit model. In the represent study of AP-1 was conjugated with the conventional DTPA dianhydride (DTPA-DA) and with 4-isothiocyanato-cyclohexyl-EDTA (4-ICE) (2 to 2.5 ligands per MAb). Labeling with {sup 57}Co was done by adding {sup 57}CoCl{sub 2} in 0.1 N HCl to 500 {mu}g of conjugate in 0.1 M NaHCO{sub 3} containing 0.12 M acetate. The reaction mixture (pH {approximately} 5.5) was allowed to stand at room temperature for 8 h, and then purified by size exclusion HPLC following EDTA chase (10 {mu}l of 0.1 M EDTA, pH 7.0, 10 min). Labeling efficiencies were >90%. When incubated with mouse serum these conjugates showed similar stability ({approximately}3% activity loss for 4-ICE vs 6% for DTPA-DA at 24 h). The inhibition of tissue factor procoagulant activity was determined for the {sup 67}Co labeled conjugates using a two stage clotting assay. In the first stage, clotting times were determined using serial dilutions of reconstituted TF standards to check linearity. In the second stage, clotting times were determined for {sup 67}Co labeled AP-1 conjugates at various dilutions (1 ng to 1 {mu}g/mL) in presence of 150 ng/ml of TF. Results were compared with those obtained using unlabeled conjugates and the native AP-1. Neither conjugation with chelators nor radiolabelling affected the TF activity of AP-1. These conjugates labeled with {sup 66}Co (t l/1 17.5 h, {beta}{sup +} emission) should prove effective for PET imaging of vessel wall injury or thrombotic disease in our previously established rabbit model. Based on our previous data with other MAbs, the 4-ICE conjugate is expected to provide better biodistribution.

  20. Pterostilbene Is Equally Potent as Resveratrol in Inhibiting 12-O-tetradecanoylphorbol-13-acetate Activated NFkappaB, AP-1, COX-2 and iNOS in Mouse Epidermis

    USDA-ARS?s Scientific Manuscript database

    Resveratrol, a phytoalexin present in grapes, has been reported to inhibit multistage mouse skin carcinogenesis. Recent studies showed that topically applied resveratrol significantly inhibited cyclooxygenase-2 (COX-2) expression and activation of nuclear factor-kB (NF-kB) induced by tumor promoter...

  1. Suppression of endothelial nitric oxide synthase expression and endothelial cell proliferation by an intronic 27-ntmiRNA and it's a novel link to AP-1.

    PubMed

    Li, Yumei; Yan, Limei; Zhang, Wenyu; Hu, Nan; Chen, Wei; Wang, Hui; Kang, Min; Ou, Hesheng

    2015-01-01

    This study aims to investigate the role of activator protein 1 (AP-1) in the effects of 27nt-miRNA on expression of endothelial nitric oxide synthase (eNOS) gene and proliferation of endothelial cells. Cell proliferation was analyzed by cell number counting, colony formation assay and MTT assay. Cell migration and invasion was detected by transwell assay and invasion assay. Expression of eNOS and AP-1 was measured by real-time RT-PCR (mRNA level) and Western blotting (protein level). Luciferase reporter assay was performed to detect the binding of 27nt-miRNA to AP-1. Overexpression of 27nt-miRNA significantly inhibited endothelial cells proliferation, invasion and migration in vitro. And, eNOS and AP-1 expression at mRNA and protein levels were down-regulated by overexpression of 27nt-miRNA. Interestingly, overexpression of AP-1 protein partially restored eNOS expression and endothelial cell proliferation. Furthermore, the luciferase reporter assay demonstrated that AP-1 was a direct target of 27nt-miRNA. These data demonstrate that overexpression of 27nt-miRNA inhibits endothelial cell proliferation, invasion, migration, eNOS expression and AP-1 expression. Moreover, AP-1, a direct target of 27nt-miRNA, reverses the inhibitory effects of 27nt-miRNA. Thus, the effects of 27nt-miRNA might be acted through targeting AP-1.

  2. Tobacco carcinogen mediated up-regulation of AP-1 dependent pro-angiogenic cytokines in head and neck carcinogenesis.

    PubMed

    Swenson, Wade G; Wuertz, Beverly R K; Ondrey, Frank G

    2011-09-01

    Tobacco is notably genotoxic and associated with head and neck carcinogenesis. Cigarette carcinogens have the capacity to alter early response gene expression in tobacco-related malignancies via genes such as nuclear factor kappa B (NFκB). A number of early response gene activation events are also facilitated by fos/jun activator protein 1 (AP-1) associated pathways. In the present study, we hypothesize that tobacco products may induce microenvironment alterations, promoting angiogenesis and providing a permissive environment for head and neck cancer progression. In an in vitro analysis, we employed immortalized oral keratinocyte (HOK-16B) and laryngeal squamous carcinoma (UM-SCC-11A) cells to investigate interleukin (IL)-8 and vascular endothelial growth factor (VEGF) induction by cigarette smoke condensate (CSC). IL-8 and VEGF expression is based on interactions between NFκB, AP-1, and NF-IL6. We identified at least 1.5-fold dose-dependent induction of AP-1, VEGF, and IL-8 promoter/reporter gene activity after 24 h exposure to CSC. Next, we stably transfected UM-SCC-11A cells with A-Fos, a dominant negative AP-1 protein. Treatment with CSC of the A-Fos cell lines compared to empty vector controls significantly down-regulated AP-1, VEGF, and IL-8 promoter/reporter gene expression. We also performed ELISAs and discovered significant up-regulation of IL-8 and VEGF secretion by UMSCC 11A after treatment with phorbol 12-myristate 13-acetate, tumor necrosis factor alpha, and CSC, which was down-regulated by the A-Fos dominant negative protein. We conclude tobacco carcinogens up-regulate AP-1 activity and AP-1 dependent IL-8 and VEGF gene expression in head and neck cancer. This up-regulation may promote an angiogenic phenotype favoring invasion in both premalignant and squamous cancer cells of the head and neck.

  3. Androgen receptor stimulates bone sialoprotein (BSP) gene transcription via cAMP response element and activator protein 1/glucocorticoid response elements.

    PubMed

    Takai, Hideki; Nakayama, Youhei; Kim, Dong-Soon; Arai, Masato; Araki, Shouta; Mezawa, Masaru; Nakajima, Yu; Kato, Naoko; Masunaga, Hiroshi; Ogata, Yorimasa

    2007-09-01

    Bone sialoprotein (BSP) is an early marker of osteoblast differentiation. Androgens are steroid hormones that are essential for skeletal development. The androgen receptor (AR) is a transcription factor and a member of the steroid receptor superfamily that plays an important role in male sexual differentiation and prostate cell proliferation. To determine the molecular mechanism involved in the stimulation of bone formation, we have analyzed the effects of androgens and AR effects on BSP gene transcription. AR protein levels were increased after AR overexpression in ROS17/2.8 cells. BSP mRNA levels were increased by AR overexpression. However, the endogenous and overexpressed BSP mRNA levels were not changed by DHT (10(-8) M, 24 h). Whereas luciferase (LUC) activities in all constructs, including a short construct (nts -116 to +60), were increased by AR overexpression, the basal and LUC activities enhanced by AR overexpression were not induced by DHT (10(-8)M, 24 h). The effect of AR overexpression was abrogated by 2 bp mutations in either the cAMP response element (CRE) or activator protein 1 (AP1)/glucocorticoid response element (GRE). Gel shift analyses showed that AR overexpression increased binding to the CRE and AP1/GRE elements. Notably, the CRE-protein complexes were supershifted by phospho-CREB antibody, and CREB, c-Fos, c-Jun, and AR antibodies disrupted the complexes formation. The AP1/GRE-protein complexes were supershifted by c-Fos antibody and c-Jun, and AR antibodies disrupted the complexes formation. These studies demonstrate that AR stimulates BSP gene transcription by targeting the CRE and AP1/GRE elements in the promoter of the rat BSP gene.

  4. Rapid, sequential activation of mitogen-activated protein kinases and transcription factors precedes proinflammatory cytokine mRNA expression in spleens of mice exposed to the trichothecene vomitoxin.

    PubMed

    Zhou, Hui-Ren; Islam, Zahidul; Pestka, James J

    2003-03-01

    Since proinflammatory cytokine mRNA expression is induced within lymphoid tissue in vivo by the trichothecene vomitoxin (VT) in a rapid (1-2 h) and transient (4-8 h) fashion, it was hypothesized that mitogen-activated protein kinases (MAPKs) and transcription factors associated upstream with gene transcription of these cytokines are activated prior to or within these time windows. To test this hypothesis, mice were first treated with a single oral dose of VT and then analyzed for MAPK phosphorylation in the spleen. As little as 1 mg/kg of VT induced JNK 1/2, ERK 1/2, and p38 phosphorylation with maximal effects being observed at 5 to 100 mg/kg of VT. VT transiently induced JNK and p38 phosphorylation over a 60-min time period with peak effects being observed at 15 and 30 min, respectively. In contrast, ERK remained phosphorylated from 15 to 120 min. Next, the binding of activating protein 1 (AP-1), CCAAT enhancer-binding protein (C/EBP), CRE-binding protein (CREB), and nuclear factor-kappaB (NF-kappaB) was measured by electrophoretic mobility shift assay (EMSA) using four different consensus transcriptional control motifs at 0, 0.5, 1.5, 4, and 8 h after oral exposure to 25 mg/kg of VT. AP-1 binding activity was differentially elevated from 0.5 h to 8 h, whereas C/EBP binding was elevated only at 0.5 h. CREB binding decreased slightly at 0.5 h but gradually increased, reaching a maximum at 4 h. NF-kappaB binding was increased only slightly at 4 and 8 h. The specificities of AP-1, C/EBP, CREB, and NF-kappaB for relevant DNA motifs were verified by competition assays, using an excess of unlabeled consensus and mutant oligonucleotides. Supershift EMSAs and Western blot analysis identified specific VT-inducible DNA binding proteins for AP-1 (cJun, phospho c-jun, JunB, and JunD), C/EBP (C/EBPbeta), CREB (CREB-1 and ATF-2), and NF-kappaB (p50 and cRel). Finally, when the effects of oral VT exposure on proinflammatory gene expression were assessed at 3, 6, and 9 h

  5. Rad51 activates polyomavirus JC early transcription.

    PubMed

    White, Martyn K; Kaminski, Rafal; Khalili, Kamel; Wollebo, Hassen S

    2014-01-01

    The human neurotropic polyomavirus JC (JCV) causes the fatal CNS demyelinating disease progressive multifocal leukoencephalopathy (PML). JCV infection is very common and after primary infection, the virus is able to persist in an asymptomatic state. Rarely, and usually only under conditions of immune impairment, JCV re-emerges to actively replicate in the astrocytes and oligodendrocytes of the brain causing PML. The regulatory events involved in the reactivation of active viral replication in PML are not well understood but previous studies have implicated the transcription factor NF-κB acting at a well-characterized site in the JCV noncoding control region (NCCR). NF-κB in turn is regulated in a number of ways including activation by cytokines such as TNF-α, interactions with other transcription factors and epigenetic events involving protein acetylation--all of which can regulate the transcriptional activity of JCV. Active JCV infection is marked by the occurrence of rapid and extensive DNA damage in the host cell and the induction of the expression of cellular proteins involved in DNA repair including Rad51, a major component of the homologous recombination-directed double-strand break DNA repair machinery. Here we show that increased Rad51 expression activates the JCV early promoter. This activation is co-operative with the stimulation caused by NF-κB p65, abrogated by mutation of the NF-κB binding site or siRNA to NFκB p65 and enhanced by the histone deacetylase inhibitor sodium butyrate. These data indicate that the induction of Rad51 resulting from infection with JCV acts through NF-κB via its binding site to stimulate JCV early transcription. We suggest that this provides a novel positive feedback mechanism to enhance viral gene expression during the early stage of JCV infection.

  6. IL-1 receptor antagonist attenuates MAP kinase/AP-1 activation and MMP1 expression in UVA-irradiated human fibroblasts induced by culture medium from UVB-irradiated human skin keratinocytes.

    PubMed

    Wang, Xiaoyong; Bi, Zhigang; Chu, Wenming; Wan, Yinsheng

    2005-12-01

    Solar UV light comprises UVB wavelengths (290-320 nm) and UVA wavelengths (320-400 nm). UVB radiation reaches the epidermis and, to a lesser extent, the upper part of the dermis, while UVA radiation penetrates more deeply into human skin. Existing studies have demonstrated that UV-irradiated epidermal keratinocytes release cytokines that indirectly promote MMP-1 production in dermal fibroblasts. In this study, we first investigated the effect of IL-1 on MAPK activity, c-Jun and c-Fos mRNA expression, and MMP-1 and MMP-2 production in UVA-irradiated human dermal fibroblasts. The results showed that UVA irradiation dose-dependently increased MMP-1 but not MMP-2 production in human skin fibroblasts. IL-1alpha and IL-1beta promoted MMP-1 but not MMP-2 production in UVA-irradiated fibroblasts. Both IL-1alpha and IL-1beta activated MAP kinase, significantly elevating c-Jun and c-Fos mRNA expression. We then investigated the indirect effect of UVB-irradiated keratinocyte culture medium on MMP-1 production in UVA-irradiated primary cultured human dermal fibroblasts and the effect of IL-1Ra. The results showed that cell culture medium from UVB-irradiated keratinocytes increased MMP-1 production in UVA-irradiated fibroblasts, and IL-1Ra dose-dependently inhibited MMP-1 production. IL-1Ra dose-dependently inhibited c-Jun mRNA expression of fibroblasts with no significant effect on c-Fos mRNA expression. These results demonstrate that UVB-irradiated keratinocytes promoted MMP-1 production in UVA-irradiated fibroblasts in a paracrine manner while IL-1Ra reduced MMP-1 production through inhibiting c-Jun mRNA expression. Collectively, our data suggest that IL-1 plays an important role in the dermal collagen degradation associated with UV-induced premature aging of the skin and IL-1Ra may be applied for the prevention and treatment of photoaging.

  7. Gallic Acid-g-Chitosan Modulates Inflammatory Responses in LPS-Stimulated RAW264.7 Cells Via NF-κB, AP-1, and MAPK Pathways.

    PubMed

    Ahn, Chang-Bum; Jung, Won-Kyo; Park, Sun-Joo; Kim, Yong-Tae; Kim, Won-Suk; Je, Jae-Young

    2016-02-01

    Chitosan is a naturally occurring polysaccharide, which has exhibited antioxidant, antimicrobial, and anti-cancer activities among others. Modification of chitosan by grafting phenolic compounds is a good strategy for improvement of bioactivities of chitosan. We investigated the anti-inflammatory action of gallic acid-grafted-chitosan (GAC) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. GAC inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2) by inhibiting inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW264.7 macrophages. GAC also suppressed the production and mRNA expression of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). GAC inactivated nuclear factor-κB (NF-κB) via inhibiting the phosphorylation and degradation of the NF-κB inhibitor, IκB. In addition, GAC suppresses the activation of activator protein-1 (AP-1) through the phosphorylation of mitogen-activated protein kinase (MAPK) such as extracellular signal-regulated kinase (ERK1/2), p38 MAPK, and c-Jun N-terminal kinase/stress-activated protein kinase (JNK). These results suggest that GAC has the potential anti-inflammatory action by downregulating transcriptional factors (NF-κB and AP-1) through MAPK signaling pathways.

  8. Persistent distention of colon damages interstitial cells of Cajal through Ca(2+) -ERK-AP-1-miR-34c-SCF deregulation.

    PubMed

    Yang, Shu; Dong, Fang; Li, Dandan; Sun, Haimei; Wu, Bo; Sun, Tingyi; Wang, Yaxi; Shen, Ping; Ji, Fengqing; Zhou, Deshan

    2017-09-01

    Gastrointestinal motility disorders (GMDs) are attributed to loss of interstitial cells of Cajal (ICC), whose survival and function are deeply dependent on the activation of KIT/SCF signalling. Based on the facts that gastrointestinal distention is common in GMD patients and SCF produced by smooth muscle cells (SMCs) is usually decreased before ICC loss, we considered a possible contribution of persistent gastrointestinal distention/stretch to SCF deficiency. In this study, chronic colonic distention mouse model, diabetic gastrointestinal paresis mouse model, cultured mouse colonic SMCs and colon specimens from Hirschsprung's disease patients were used. The results showed that SCF was clearly decreased in distent colon of mice and patients, and microRNA array and real-time PCR indicated a concomitant increase of miR-34c in distent colon. A negative regulation of miR-34c on SCF expression was confirmed by luciferase reporter assays together with knock-down and overexpression of miR-34c in cultured colonic SMCs. Using EMSA and ChIP assays, we further consolidated that in response to persistent stretch, the transcription factor AP-1/c-Jun was highly activated in colonic SMCs and significantly promoted miR-34c transcription by binding to miR-34c promoter. Knock-down or overexpression of AP-1/c-Jun in cultured colonic SMCs leads to down- or up-regulation of miR-34c, respectively. In addition, the activation of AP-1/c-Jun was through ERK1/2 signalling provoked by Ca(2+) overload in colonic SMCs that were subject to persistent stretch. In conclusion, our data demonstrated that persistent distention/stretch on colonic SMCs could suppress SCF production probably through Ca(2+) -ERK-AP-1-miR-34c deregulation, resulting in ICC loss or impairment and GMD progress. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  9. [6]-Gingerol induces caspase-dependent apoptosis and prevents PMA-induced proliferation in colon cancer cells by inhibiting MAPK/AP-1 signaling.

    PubMed

    Radhakrishnan, E K; Bava, Smitha V; Narayanan, Sai Shyam; Nath, Lekshmi R; Thulasidasan, Arun Kumar T; Soniya, Eppurathu Vasudevan; Anto, Ruby John

    2014-01-01

    We report mechanism-based evidence for the anticancer and chemopreventive efficacy of [6]-gingerol, the major active principle of the medicinal plant, Ginger (Zingiber officinale), in colon cancer cells. The compound was evaluated in two human colon cancer cell lines for its cytotoxic effect and the most sensitive cell line, SW-480, was selected for the mechanistic evaluation of its anticancer and chemopreventive efficacy. The non-toxic nature of [6]-gingerol was confirmed by viability assays on rapidly dividing normal mouse colon cells. [6]-gingerol inhibited cell proliferation and induced apoptosis as evidenced by externalization of phosphatidyl serine in SW-480, while the normal colon cells were unaffected. Sensitivity to [6]-gingerol in SW-480 cells was associated with activation of caspases 8, 9, 3 &7 and cleavage of PARP, which attests induction of apoptotic cell death. Mechanistically, [6]-gingerol down-regulated Phorbol Myristate Acetate (PMA) induced phosphorylation of ERK1/2 and JNK MAP kinases and activation of AP-1 transcription factor, but had only little effects on phosphorylation of p38 MAP kinase and activation of NF-kappa B. Additionally, it complemented the inhibitors of either ERK1/2 or JNK MAP kinase in bringing down the PMA-induced cell proliferation in SW-480 cells. We report the inhibition of ERK1/2/JNK/AP-1 pathway as a possible mechanism behind the anticancer as well as chemopreventive efficacy of [6]-gingerol against colon cancer.

  10. Fargesin exerts anti-inflammatory effects in THP-1 monocytes by suppressing PKC-dependent AP-1 and NF-ĸB signaling.

    PubMed

    Pham, Thu-Huyen; Kim, Man-Sub; Le, Minh-Quan; Song, Yong-Seok; Bak, Yesol; Ryu, Hyung-Won; Oh, Sei-Ryang; Yoon, Do-Young

    2017-01-15

    Fargesin is a lignan from Magnolia fargesii, an oriental medicine used in the treatment of nasal congestion and sinusitis. The anti-inflammatory properties of this compound have not been fully elucidated yet. This study focused on assessing the anti-inflammatory effects of fargesin on phorbal ester (PMA)-stimulated THP-1 human monocytes, and the molecular mechanisms underlying them. Cell viability was evaluated by MTS assay. Protein expression levels of inflammatory mediators were analyzed by Western blotting, ELISA, Immunofluorescence assay. mRNA levels were measured by Real-time PCR. Promoter activities were elucidated by Luciferase assay. It was found that pre-treatment with fargesin attenuated significantly the expression of two major inflammatory mediators, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). Fargesin also inhibited the production of pro-inflammation cytokines (IL-1β, TNF-α) and chemokine (CCL-5). Besides, nuclear translocation of transcription factors nuclear factor-kappa B (NF-ĸB) and activator protein-1 (AP-1), which regulate multiple pro-inflammatory genes, was suppressed by fargesin in a PKC-dependent manner. Furthermore, among the mitogen-activated protein kinases (MAPKs), only c-Jun N-terminal kinase (JNK) was downregulated by fargesin in a PKC-dependent manner, and this reduction was involved in PMA-induced AP-1 and NF-ĸB nuclear translocation attenuation, demonstrated using a specific JNK inhibitor. Taken together, our results found that fargesin exhibits anti-inflammation effects on THP-1 cells via suppression of PKC pathway including downstream JNK, nuclear factors AP-1 and NF-ĸB. These results suggest that fargesin has anti-inflammatory properties with potential applications in drug development against inflammatory disorders. Copyright © 2016. Published by Elsevier GmbH.

  11. Lead induces COX-2 expression in glial cells in a NFAT-dependent, AP-1/NFκB-independent manner

    PubMed Central

    Wei, Jinlong; Du, Kejun; Cai, Qinzhen; Ma, Lisha; Jiao, Zhenzhen; Tan, Jinrong; Xu, Zhou; Li, Jingxia; Luo, Wenjin; Chen, Jingyuan; Gao, Jimin; Zhang, Dongyun; Huang, Chuanshu

    2014-01-01

    Epidemiologic studies have provided solid evidence for the neurotoxic effect of lead for decades of years. In view of the fact that children are more vulnerable to the neurotoxicity of lead, lead exposure has been an urgent public health concern for decades of years. The modes of action of lead neurotoxic effects include disturbance of neurotransmitter storage and release, damage of mitochondria, as well as induction of apoptosis in cerebrovascular endothelial cells, astroglia and oligodendroglia. Our studies here, from a novel point of view, demonstrates that lead specifically caused induction of COX-2, a well known inflammatory mediator in neurons and glia cells. Furthermore, we revealed that COX-2 was induced by lead in a transcription-dependent manner, which relayed on transcription factor NFAT, rather than AP-1 and NFκB, in glial cells. Considering the important functions of COX-2 in mediation of inflammation reaction and oxidative stress, our studies here provide a mechanistic insight into the understanding of lead-associated inflammatory neurotoxicity effect via activation of pro-inflammatory NFAT3/COX-2 axis. PMID:25193092

  12. TLR4-NOX4-AP-1 signaling mediates lipopolysaccharide-induced CXCR6 expression in human aortic smooth muscle cells

    SciTech Connect

    Patel, Devang N.; Bailey, Steven R.; Gresham, John K.; Schuchman, David B.; Shelhamer, James H.; Goldstein, Barry J.; Foxwell, Brian M.; Stemerman, Michael B.; Maranchie, Jodi K.; Valente, Anthony J.; Mummidi, Srinivas; Chandrasekar, Bysani . E-mail: chandraseka@uthscsa.edu

    2006-09-08

    CXCL16 is a transmembrane non-ELR CXC chemokine that signals via CXCR6 to induce aortic smooth muscle cell (ASMC) proliferation. While bacterial lipopolysaccharide (LPS) has been shown to stimulate CXCL16 expression in SMC, its effects on CXCR6 are not known. Here, we demonstrate that LPS upregulates CXCR6 mRNA, protein, and surface expression in human ASMC. Inhibition of TLR4 with neutralizing antibodies or specific siRNA interference blocked LPS-mediated CXCR6 expression. LPS stimulated both AP-1 (c-Fos, c-Jun) and NF-{kappa}B (p50 and p65) activation, but only inhibition of AP-1 attenuated LPS-induced CXCR6 expression. Using dominant negative expression vectors and siRNA interference, we demonstrate that LPS induces AP-1 activation via MyD88, TRAF6, ERK1/2, and JNK signaling pathways. Furthermore, the flavoprotein inhibitor diphenyleniodonium chloride significantly attenuated LPS-mediated AP-1-dependent CXCR6 expression, as did inhibition of NOX4 NADPH oxidase by siRNA. Finally, CXCR6 knockdown inhibited CXCL16-induced ASMC proliferation. These results demonstrate that LPS-TLR4-NOX4-AP-1 signaling can induce CXCR6 expression in ASMC, and suggest that the CXCL16-CXCR6 axis may be an important proinflammatory pathway in the pathogenesis of atherosclerosis.

  13. Profilin is associated with transcriptionally active genes

    PubMed Central

    Söderberg, Emilia; Hessle, Viktoria; von Euler, Anne; Visa, Neus

    2012-01-01

    We have raised antibodies against the profilin of Chironomus tentans to study the location of profilin relative to chromatin and to active genes in salivary gland polytene chromosomes. We show that a fraction of profilin is located in the nucleus, where profilin is highly concentrated in the nucleoplasm and at the nuclear periphery. Moreover, profilin is associated with multiple bands in the polytene chromosomes. By staining salivary glands with propidium iodide, we show that profilin does not co-localize with dense chromatin. Profilin associates instead with protein-coding genes that are transcriptionally active, as revealed by co-localization with hnRNP and snRNP proteins. We have performed experiments of transcription inhibition with actinomycin D and we show that the association of profilin with the chromosomes requires ongoing transcription. However, the interaction of profilin with the gene loci does not depend on RNA. Our results are compatible with profilin regulating actin polymerization in the cell nucleus. However, the association of actin with the polytene chromosomes of C. tentans is sensitive to RNase, whereas the association of profilin is not, and we propose therefore that the chromosomal location of profilin is independent of actin. PMID:22572953

  14. Repurposing CRISPR System for Transcriptional Activation.

    PubMed

    Chen, Meng; Qi, Lei Stanley

    2017-01-01

    In recent years, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system has become the most popular one for genome editing. When the nuclease domains of Cas9 protein are mutated into deactivated form (dCas9), CRISPR/dCas9 still retains the ability to bind the targeted DNA sequence, but loses the endonuclease cleavage activity. Taking advantage of the characteristics of this engineered nuclease inactive Cas9, the CRISPR/dCas system has been repurposed into versatile RNA-guided, DNA-targeting platforms, such as genome imaging, gene regulation, and epigenetic modification. Specifically, fusion of dCas9 with activation domains allows specific and efficient transcriptional activation on a genome-wide scale among diverse organisms. The purpose of this chapter is to review most important the recently published literature on CRISPR/dCas9-based transcriptional activation systems. Compared with the conventional approaches for enhancement of the expression of specific genes of interest, CRISPR/Cas9-based system has emerged as a promising technology for genome regulation, allowing specificity, convenience, robustness, and scalability for endogenous gene activation.

  15. Extrachromosomal HPV-16 LCR transcriptional activation by HDACi opposed by cellular differentiation and DNA integration

    PubMed Central

    Bojilova, Ekaterina Dimitrova; Weyn, Christine; Antoine, Marie-Hélène; Fontaine, Véronique

    2016-01-01

    Histone deacetylase inhibitors (HDACi) have been shown to render HPV-carrying cells susceptible to intrinsic and extrinsic apoptotic signals. As such, these epigenetic drugs have entered clinical trials in the effort to treat cervical cancer. Here, we studied the effect of common HDACi, with an emphasis on Trichostatin A (TSA), on the transcriptional activity of the HPV-16 Long Control Region (LCR) in order to better understand the impact of these agents in the context of the HPV life cycle and infection. HDACi strongly induced transcription of the firefly luciferase reporter gene under the control of the HPV-16 LCR in a variety of cell lines. In the HaCaT keratinocyte cell line undergoing differentiation induced by TSA, we observed a reduction in LCR-controlled transcription. Three major AP-1 binding sites in the HPV-16 LCR are involved in the regulation by TSA. However, whatever the status of differentiation of the HaCaT cells, TSA induced integration of extra-chromosomal transfected DNA into the cellular genome. Although these data suggest caution using HDACi in the treatment of HR HPV infection, further in vivo studies are necessary to better assess the risk. PMID:27705914

  16. Age-associated changes in basal c-fos transcription factor binding activity in rat hearts.

    PubMed

    Tsou, H; Azhar, G; Lu, X G; Kovacs, S; Peacocke, M; Wei, J Y

    1996-12-15

    The early response proto-oncogene c-fos is expressed at very low levels in the mammalian heart at baseline. To further investigate the mechanism of altered c-fos expression with age, we studied in the basal state the binding of five transcription proteins to their cognate sites in the c-fos promoter/enhancer region, in adult and old F344 rats. Our results show a reduced binding of E2F and AP1 proteins to the c-fos promoter in aging hearts. The major calcium/cyclic AMP response element (CRE) and SP1 binding was unchanged. The only increase seen with age was in the serum response element (SRE) binding proteins. SRE is the point of convergence of different signal transduction pathways (via MAP kinases and the Rho family of GTPases) at the c-fos promoter. Increased SRE binding may reflect a compensation for a decreased binding of other transcription proteins to the c-fos promoter, alteration in the phosphorylation status of SRF, or a change in the ternary complex factors Elk 1 or SAP 1. Other possibilities include defects in the signal transduction pathways with aging, which combine to produce an overall negative balance in the function of the c-fos promoter despite the increased SRE binding activity. Both in vitro and in vivo experiments have shown decreased c-fos expression with age. This may be due partly to alterations in the basal levels of transcription factor binding.

  17. Saccharomyces cerevisiae exhibits a yAP-1-mediated adaptive response to malondialdehyde.

    PubMed Central

    Turton, H E; Dawes, I W; Grant, C M

    1997-01-01

    Malondialdehyde (MDA) is a highly reactive aldehyde generally formed as a consequence of lipid peroxidation. MDA has been inferred to have mutagenic and cytotoxic roles and possibly to be a participant in the onset of atherosclerosis. Wild-type Saccharomyces cerevisiae acquires resistance to a lethal dose (5 mM) of MDA following prior exposure to a nonlethal concentration (1 mM). This response was completely inhibited by cycloheximide (50 microg ml(-1)), indicating a requirement for protein synthesis for adaptation. Furthermore, we have examined the roles of glutathione (GSH), mitochondrial function, and yAP-1-mediated transcription in conferring resistance and adaptation to MDA. A yap1 disruption mutant exhibited the greatest sensitivity and was unable to adapt to MDA, implicating yAP-1 in both the adaptive response and constitutive survival. The effect of MDA on GSH mutants indicated a role for GSH in initial resistance, whereas resistance acquired through adaptation was independent of GSH. Likewise, respiratory mutants (petite mutants) were sensitive to MDA but were still able to mount an adaptive response similar to that of the wild type, excluding mitochondria from any role in adaptation. MDA was detected in yeast cells by the thiobarbituric acid test and subsequent high-pressure liquid chromatography separation. Elevated levels were detected following treatment with hydrogen peroxide. However, the MDA-adaptive response was independent of that to H2O2. PMID:9023189

  18. RAD51AP2, a novel vertebrate- and meiotic-specific protein, sharesa conserved RAD51-interacting C-terminal domain with RAD51AP1/PIR51

    SciTech Connect

    Kovalenko, Oleg V.; Wiese, Claudia; Schild, David

    2006-07-25

    Many interacting proteins regulate and/or assist the activities of RAD51, a recombinase which plays a critical role in both DNA repair and meiotic recombination. Yeast two-hybrid screening of a human testis cDNA library revealed a new protein, RAD51AP2 (RAD51 Associated Protein 2), that interacts strongly with RAD51. A full-length cDNA clone predicts a novel vertebrate specific protein of 1159 residues, and the RAD51AP2 transcript was observed only in meiotic tissue (i.e. adult testis and fetal ovary), suggesting a meiotic-specific function for RAD51AP2. In HEK293 cells the interaction of RAD51 with an ectopically-expressed recombinant large fragment of RAD51AP2 requires the C-terminal 57 residues of RAD51AP2. This RAD51-binding region shows 81% homology to the C-terminus of RAD51AP1/PIR51, an otherwise totally unrelated RAD51-binding partner that is ubiquitously expressed. Analyses using truncations and point mutations in both RAD51AP1 and RAD51AP2 demonstrate that these proteins use the same structural motif for RAD51 binding. RAD54 shares some homology with this RAD51-binding motif, but this homologous region plays only an accessory role to the adjacent main RAD51-interacting region, which has been narrowed here to 40 amino acids. A novel protein, RAD51AP2, has been discovered that interacts with RAD51 through a C-terminal motif also present in RAD51AP1.

  19. Anti-inflammatory effects of proanthocyanidin-rich red rice extract via suppression of MAPK, AP-1 and NF-κB pathways in Raw 264.7 macrophages

    PubMed Central

    Yodkeeree, Supachai; Pitchakarn, Pornsiri; Punfa, Wanisa

    2016-01-01

    BACKGROUND/OBJECTIVES Several pharmacological properties of red rice extract have been reported including anti-oxidant, anti-tumor, and reduced cancer cell invasion. This study was conducted to evaluate the anti-inflammatory effects of red rice extract on the production of inflammatory mediators in lipopolysaccharide (LPS)-induced Raw 264.7 macrophages. MATERIALS/METHODS Pro-inflammatory cytokines including tumor necrosis factor-α and interleukin-6 were determined by ELISA and cyclooxygenase-2 and inducible nitric oxide synthase expression was evaluated using western blot analysis. In addition, the signaling pathway controlling the inflammatory cascade such as nuclear factor kappa B (NF-κB), activator proteins-1 (AP-1), and mitogen-activated protein kinase (MAPK) was determined. RESULTS Our results showed that red rice polar extract fraction (RR-P), but not non-polar extract fraction, inhibited interleukin-6, tumor necrosis factor-α, and nitric oxide production in LPS-induced Raw 264.7 cells. RR-P also reduced the expression of inflammatory enzymes, inducible nitric oxide synthase, and cyclooxygenase-2. In addition, activation of AP-1 and NF-κB transcription factor in the nucleus was abrogated by RR-P. RR-P inhibited the phosphorylation of extracellular signaling-regulated kinase 1/2, c-Jun NH2-terminal kinase, and p38 MAPK signaling responsible for the expression of inflammatory mediators in LPS-stimulated Raw 264.7 cells. Based on chemical analysis, high amounts of proanthocyanidin and catechins were detected in the RR-P fraction. However, only proanthocyanidin reduced NF-κB and AP-1 activation in LPS-activated Raw 264.7 cells. CONCLUSION These observations suggest that the anti-inflammatory properties of RR-P may stem from the inhibition of pro-inflammatory mediators via suppression of the AP-1, NF-κB, and MAPKs pathways. PMID:27247720

  20. Tumor necrosis factor alpha activates transcription of the NADPH oxidase organizer 1 (NOXO1) gene and upregulates superoxide production in colon epithelial cells.

    PubMed

    Kuwano, Yuki; Tominaga, Kumiko; Kawahara, Tsukasa; Sasaki, Hidekazu; Takeo, Keiko; Nishida, Kensei; Masuda, Kiyoshi; Kawai, Tomoko; Teshima-Kondo, Shigetada; Rokutan, Kazuhito

    2008-12-15

    NADPH oxidase 1 (Nox1) is a multicomponent enzyme consisting of p22(phox), Nox organizer 1 (NOXO1), Nox1 activator 1, and Rac1. Interleukin-1beta, flagellin, interferon-gamma, and tumor necrosis factor alpha (TNF-alpha) similarly induced Nox1 in a colon cancer cell line (T84), whereas only TNF-alpha fully induced NOXO1 and upregulated superoxide-producing activity by ninefold. This upregulation was canceled by knockdown of NOXO1 with small interfering RNAs. TNF-alpha rapidly phosphorylated p38 mitogen-activated protein kinase and c-Jun N-terminal kinase 1/2, followed by phosphorylation of c-Jun and c-Fos and appearance of an AP-1 binding activity within 30 min. We cloned the 5' flank of the human NOXO1 gene (-3888 to +263 bp), and found that the region between -585 and -452 bp, which contains consensus elements of YY-1, AP-1, and Ets, and the GC-rich region encoding three putative binding sites for SP-1, was crucial for TNF-alpha-dependent promoter activity. Serial mutation analysis of the elements identified an AP-1 binding site (from -561 to -551 bp, agtAAGtcatg) as a crucial element for TNF-alpha-stimulated transcription of the human NOXO1 gene, which was also confirmed by the AP-1 decoy experiments. Thus, TNF-alpha acts as a potent activator of Nox1-based oxidase in colon epithelial cells, suggesting a potential role of this oxidase in inflammation of the colon.

  1. Cytokine induction of NO synthase II in human DLD-1 cells: roles of the JAK-STAT, AP-1 and NF-kappaB-signaling pathways.

    PubMed

    Kleinert, H; Wallerath, T; Fritz, G; Ihrig-Biedert, I; Rodriguez-Pascual, F; Geller, D A; Förstermann, U

    1998-09-01

    1. In human epithelial-like DLD-I cells, nitric oxide synthase (NOS) II expression was induced by interferon-gamma (100 u ml(-1)) alone and, to a larger extent, by a cytokine mixture (CM) consisting of interferon-gamma, interleukin-1beta (50 u ml(-1)) and tumor necrosis factor-alpha (10 ng ml(-1)). 2. CM-induced NOS II expression was inhibited by tyrphostin B42 (mRNA down to 1%; nitrite production down to 0.5% at 300 microM) and tyrphostin A25 (mRNA down to 24%, nitrite production down to 1% at 200 microM), suggesting the involvement of janus kinase 2 (JAK-2). Tyrphostin B42 also blocked the CM-induced JAK-2 phosphorylation (kinase assay) and reduced the CM-stimulated STAT1alpha binding activity (gel shift analysis). 3. CM reduced the nuclear binding activity of transcription factor AP-1. A heterogenous group of compounds, that stimulated the expression of c-fos/c-jun, enhanced the nuclear binding activity of AP-1. This group includes the protein phosphatase inhibitors calyculin A, okadaic acid, and phenylarsine oxide, as well as the inhibitor of translation anisomycin. All of these compounds reduced CM-induced NOS II mRNA expression (to 9% at 50 nM calyculin A; to 28% at 500 nM okadaic acid; to 18% at 10 microM phenylarsine oxide; and to 19% at 100 ng ml(-1) anisomycin) without changing NOS II mRNA stability. In cotransfection experiments, overexpression of c-Jun and c-Fos reduced promoter activity of a 7 kb DNA fragment of the 5'-flanking sequence of the human NOS II gene to 63%. 4. Nuclear extracts from resting DLD-1 cells showed significant binding activity for transcription factor NF-kappaB, which was only slightly enhanced by CM. The NF-kappaB inhibitors dexamethasone (1 microM), 3,4-dichloroisocoumarin (50 microM), panepoxydone (5 microg ml(-1)) and pyrrolidine dithiocarbamate (100 microM) produced no inhibition of CM-induced NOS II induction. 5. We conclude that in human DLD-1 cells, the interferon-gamma-JAK-2-STAT1alpha pathway is important for NOS II

  2. Terminal epidermal differentiation is regulated by the interaction of Fra-2/AP-1 with Ezh2 and ERK1/2

    PubMed Central

    Wurm, Stefanie; Zhang, Jisheng; Guinea-Viniegra, Juan; García, Fernando; Muñoz, Javier; Bakiri, Latifa; Ezhkova, Elena

    2015-01-01

    Altered epidermal differentiation characterizes numerous skin diseases affecting >25% of the human population. Here we identified Fra-2/AP-1 as a key regulator of terminal epidermal differentiation. Epithelial-restricted, ectopic expression of Fra-2 induced expression of epidermal differentiation genes located within the epidermal differentiation complex (EDC). Moreover, in a papilloma-prone background, a reduced tumor burden was observed due to precocious keratinocyte differentiation by Fra-2 expression. Importantly, loss of Fra-2 in suprabasal keratinocytes is sufficient to cause skin barrier defects due to reduced expression of differentiation genes. Mechanistically, Fra-2 binds and transcriptionally regulates EDC gene promoters, which are co-occupied by the transcriptional repressor Ezh2. Fra-2 remains transcriptionally inactive in nondifferentiated keratinocytes, where it was found monomethylated and dimethylated on Lys104 and interacted with Ezh2. Upon keratinocyte differentiation, Fra-2 is C-terminally phosphorylated on Ser320 and Thr322 by ERK1/2, leading to transcriptional activation. Thus, the induction of epidermal differentiation by Fra-2 is controlled by a dual mechanism involving Ezh2-dependent methylation and activation by ERK1/2-dependent phosphorylation. PMID:25547114

  3. The role of NF-AT transcription factors in T cell activation and differentiation.

    PubMed

    Serfling, E; Berberich-Siebelt, F; Chuvpilo, S; Jankevics, E; Klein-Hessling, S; Twardzik, T; Avots, A

    2000-10-20

    The family of genuine NF-AT transcription factors consists of four members (NF-AT1 [or NF-ATp], NF-AT2 [or NF-ATc], NF-AT3 and NF-AT4 [or NF-ATx]) which are characterized by a highly conserved DNA binding domain (is designated as Rel similarity domain) and a calcineurin binding domain. The binding of the Ca(2+)-dependent phosphatase calcineurin to this region controls the nuclear import and exit of NF-ATs. This review deals (1) with the structure of NF-AT proteins, (2) the DNA binding of NF-AT factors and their interaction with AP-1, (3) NF-AT target genes, (4) signalling pathways leading to NF-AT activation: the role of protein kinases and calcineurin, (5) the nuclear entry and exit of NF-AT factors, (6) transcriptional transactivation by NF-AT factors, (7) the structure and expression of the chromosomal NF-AT2 gene, and (8) NF-AT factors in Th cell differentiation. The experimental data presented and discussed in the review show that NF-AT factors are major players in the control of T cell activation and differentiation and, in all likelihood, also of the cell cycle and apoptosis of T lymphocytes.

  4. Berberine attenuates high glucose-induced proliferation and extracellular matrix accumulation in mesangial cells: involvement of suppression of cell cycle progression and NF-κB/AP-1 pathways.

    PubMed

    Lan, Tian; Wu, Teng; Chen, Cheng; Chen, Xiaolan; Hao, Jie; Huang, Junying; Wang, Lijing; Huang, Heqing

    2014-03-25

    Berberine has been shown to have renoprotective effects on diabetes through attenuating TGF-β1 and fibronectin (FN) expression. However, how berberine regulates TGF-β1 and FN is not fully clear. Here we investigated whether berberine inhibited TGF-β1 and FN expression in high glucose-cultured mesangial cells. Berberine significantly inhibited mesangial cell proliferation and hypertrophy by increasing the cell population in G1-phase and reducing that in S-phase. In addition, berberine reversed high glucose-induced down-regulation of cyclin-dependent kinase inhibitor p21(Waf1)/(Cip1) and p27(Kip1). Berberine inhibited p65 translocation to the nucleus and c-jun phosphorylation induced by high glucose. Furthermore, berberine attenuated high glucose-induced expression of TGF-β1 and FN. Using a luciferase reporter assay, we found that high glucose-induced transcription activity of NF-κB and AP-1 was blocked by berberine. Electrophoretic mobility shift assay showed that high glucose increased that NF-κB and AP-1 DNA binding activity. These data indicate that berberine inhibited mesangial cell proliferation and hypertrophy by modulating cell cycle progress. In addition, berberine suppressed high glucose-induced TGF-β1 and FN expression by blocking NF-κB/AP-1 pathways.

  5. Transcriptional Tools: Small Molecules for Modulating CBP KIX-dependent Transcriptional Activators

    PubMed Central

    Bates, Caleb A.; Pomerantz, William C.; Mapp, Anna K.

    2010-01-01

    Previously it was demonstrated that amphipathic isoxazolidines are able to functionally replace the transcriptional activation domains of endogenous transcriptional activators. In addition, in vitro binding studies suggested that a key binding partner of these molecules is the Creb Binding Protein (CBP), more specifically the KIX domain with this protein. Here we show that CBP and the KIX domain play an essential role in the ability of isoxazolidine transcriptional activation domains to activate transcription in cells. Consistent with this model, isoxazolidines are able to function as competitive inhibitors of the activators MLL and Jun, both of which utilize a binding interaction with KIX to up-regulate transcription. Further, modification of the N2 side chain produced two analogs with enhanced potency against Jun-mediated transcription, although increased cytotoxicity was also observed. Collectively these small KIX-binding molecules will be useful tools for dissecting the role of the KIX domain in a variety of pathological processes. PMID:20882601

  6. Duplication of AP1 within the Spinacia oleracea L. AP1/FUL clade is followed by rapid amino acid and regulatory evolution.

    PubMed

    Sather, D Noah; Golenberg, Edward M

    2009-02-01

    The AP1/FUL clade of MADS box genes have undergone multiple duplication events among angiosperm species. While initially identified as having floral meristem identity and floral organ identity function in Arabidopsis, the role of AP1 homologs does not appear to be universally conserved even among eudicots. In comparison, the role of FRUITFULL has not been extensively explored in non-model species. We report on the isolation of three AP1/FUL genes from cultivated spinach, Spinacia oleracea L. Two genes, designated SpAPETALA1-1 (SpAP1-1) and SpAPETALA1-2 (SpAP1-2), cluster as paralogous genes within the Caryophyllales AP1 clade. They are highly differentiated in the 3', carboxyl-end encoding region of the gene following the third amphipathic alpha-helix region, while still retaining some elements of a signature AP1 carboxyl motifs. In situ hybridization studies also demonstrate that the two paralogs have evolved different temporal and spatial expression patterns, and that neither gene is expressed in the developing sepal whorl, suggesting that the AP1 floral organ identity function is not conserved in spinach. The spinach FRUITFULL homolog, SpFRUITFULL (SpFUL), has retained the conser