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Sample records for activate mapks ap-1

  1. Transcriptional suppression of IL-27 production by Mycobacterium tuberculosis-activated p38 MAPK via inhibition of AP-1 binding.

    PubMed

    Zhang, Jidong; Qian, Xuesong; Ning, Huan; Eickhoff, Christopher S; Hoft, Daniel F; Liu, Jianguo

    2011-05-15

    Mycobacterium tuberculosis remains a major global challenge to human health care, and the mechanisms of how M. tuberculosis evades host immune surveillance to favor its survival are still largely unknown. In this study, we found that bacillus Calmette-Guérin (BCG) and viable M. tuberculosis as well as M. tuberculosis lysates could activate IL-27 expression in human and mouse macrophages by induction of p28 subunit transcription. However, in parallel with these effects, BCG and M. tuberculosis lysate stimulation of macrophages induced activation of p38 MAPK signaling molecules MLK3/MKK3/MK2 to prevent maximal IL-27 production. M. tuberculosis lysate-induced p28 transcription was dependent on MyD88 signaling pathway. AP-1/c-Fos was shown to bind directly to the p28 promoter and induce p28 expression after M. tuberculosis lysate stimulation. Overexpression of p38α inhibited the binding of c-Fos to the p28 promoter but had no effect on c-Fos protein expression or phosphorylation in response to M. tuberculosis lysate stimulation. Furthermore, blockade of p38 by SB203580 enhanced M. tuberculosis-induced AP-1 binding to the p28 promoter. Importantly, we show that adding exogenous IL-27 to increase the levels produced by PBMCs stimulated with live mycobacteria enhanced the ability of BCG-expanded T cells to inhibit intracellular mycobacterial growth in human macrophages. Taken together, our data demonstrate that mycobacterial stimulation induces both IL-27 production and p38 MAPK activation. Strategies designed to tip the balance toward positive regulation of p28 induction by mycobacteria could lead to enhanced protective tuberculosis immunity. PMID:21482740

  2. The Role of JNK and p38 MAPK Activities in UVA-Induced Signaling Pathways Leading to AP-1 Activation and c-Fos Expression1

    PubMed Central

    Silvers, Amy L; Bachelor, Michael A; Bowden, G Timothy

    2003-01-01

    Abstract To further delineate ultraviolet A (UVA) signaling pathways in the human keratinocyte cell line HaCaT, we examined the potential role of mitogen-activated protein kinases (MAPKs) in UVA-induced activator protein-1 (AP-1) transactivation and c-Fos expression. UVA-induced phosphorylation of p38 and c-Jun N-terminal kinase (JNK) proteins was detected immediately after irradiation and disappeared after approximately 2 hours. Conversely, phosphorylation of extracellular signal-regulated kinase was significantly inhibited for up to 1 hour post-UVA irradiation. To examine the role of p38 and JNK MAPKs in UVA-induced AP-1 and c-fos transactivations, the selective pharmacologic MAPK inhibitors, SB202190 (p38 inhibitor) and SP600125 (JNK inhibitor), were used to independently treat stably transfected HaCaT cells in luciferase reporter assays. Both SB202190 and SP600125 dose-dependently inhibited UVA-induced AP-1 and c-fos transactivations. SB202190 (0.25–0.5 µM) and SP600125 (62–125 nM) treatments also primarily inhibited UVA-induced c-Fos expression. These results demonstrated that activation of both JNK and p38 play critical role in UVA-mediated AP-1 transactivation and c-Fos expression in these human keratinocyte cells. Targeted inhibition of these MAPKs with their selective pharmacologic inhibitors may be effective chemopreventive strategies for UVA-induced nonmelanoma skin cancer. PMID:14511403

  3. 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

  4. Silibinin suppresses PMA-induced MMP-9 expression by blocking the AP-1 activation via MAPK signaling pathways in MCF-7 human breast carcinoma cells.

    PubMed

    Lee, Syng-Ook; Jeong, Yun-Jeong; Im, Hyo Gwon; Kim, Cheorl-Ho; Chang, Young-Chae; Lee, In-Seon

    2007-03-01

    Matrix metalloproteinase-9 (MMP-9) plays an important role in the invasion and metastasis of cancer cells. In this study, we examined the inhibitory effect of silibinin, a flavonoid antioxidant from milk thistle (Silybum marianum L.) on PMA-induced MMP-9 expression in MCF-7 human breast carcinoma cells. Silibinin significantly and selectively suppressed PMA-induced MMP-9 expression in MCF-7. Silibinin has been found to inhibit PMA-induced MMP-9 gene transcriptional activity by blocking the activation of AP-1 via MAPK signaling pathways. Moreover, the Matrigel invasion assay showed that silibinin reduces PMA-induced invasion of MCF-7 cells. These results suggest that silibinin represents a potential anti-metastatic agent suppressing PMA-induced cancer cell invasion through the specific inhibition of AP-1-dependent MMP-9 gene expression. PMID:17214970

  5. 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

  6. 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

    2016-01-01

    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

  7. 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.

  8. MAPK/AP-1 signal pathway in tobacco smoke-induced cell proliferation and squamous metaplasia in the lungs of rats.

    PubMed

    Zhong, Cai-Yun; Zhou, Ya-Mei; Douglas, Gordon C; Witschi, Hanspeter; Pinkerton, Kent E

    2005-12-01

    Overwhelming evidence has demonstrated tobacco smoke (TS) is causally associated with various types of cancers, especially lung cancer. Sustained epithelial cell hyperplasia and squamous metaplasia are considered as preneoplastic lesions during the formation of lung cancer. The cellular and molecular mechanisms leading to lung cancer due to TS are not clear. Mitogen-activated protein kinases (MAPK)/activator protein-1 (AP-1) can be activated by various stimuli and play a critical role in the control of cell proliferation and differentiation. To date, information on the response of the MAPK/AP-1 pathway during hyperplasia and squamous metaplasia induced by TS is lacking. We therefore investigated the effects of TS on the development of epithelial hyperplasia and squamous metaplasia, regulation of MAPK/AP-1 activation, and expression of AP-1-regulated cell cycle proteins and differentiation markers in the lungs of rats. Exposure of rats to TS (30 mg/m(3) or 80 mg/m(3), 6 h/day, 3 days/week for 14 weeks) dramatically induced cell proliferation and squamous metaplasia in a dose-dependent manner, effects that paralleled the activation of AP-1-DNA binding activity. Phosphorylated ERK1/2, JNK, p38 and ERK5 were significantly increased by exposure to TS, indicating the activation of these MAPK pathways. Expression of Jun and Fos proteins were differentially regulated by TS. TS upregulated the expression of AP-1-dependent cell cycle proteins including cyclin D1 and proliferating cell nuclear antigen (PCNA). Among the AP-1-dependent cell differentiation markers, keratin 5 and 14 were upregulated, while loricrin, filaggrin and involucrin were downregulated following TS exposure. These findings suggest the important role of MAPK/AP-1 pathway in TS-induced pathogenesis, thus providing new insights into the molecular mechanisms of TS-associated lung diseases including lung cancers. PMID:16051644

  9. 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

  10. Macrophage-derived BAFF induces AID expression through the p38MAPK/CREB and JNK/AP-1 pathways.

    PubMed

    Kim, Hyun-A; Seo, Goo-Young; Kim, Pyeung-Hyeun

    2011-03-01

    BAFF is expressed primarily by macrophages and DCs. BAFF stimulates the differentiation and survival of B cells and induces Ig production. We have demonstrated previously that murine macrophages treated with TGF-β1 or IFN-γ express membrane-bound and soluble forms of BAFF. The ability of these two forms of BAFF to induce expression of AID, which plays a critical role in Ig CSR in B cells, was investigated. Both forms of BAFF, derived from macrophages activated by IFN-γ or TGF-β1, can increase AID expression. Subsequent analysis of BAFF signaling suggested that BAFF induces AID through BCMA, a BAFF-receptor, and p38MAPK and CREB act as intermediates in AID expression. In addition, JNK and AP-1 have similar activities. Our findings suggest that macrophage-derived BAFF stimulates B cells to express AID through BCMA and at least two different pathways, including the p38MAPK/CREB and the JNK/AP-1 pathways. PMID:21169521

  11. 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.

  12. 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.

  13. 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

  14. Thrombin induces endothelial arginase through AP-1 activation.

    PubMed

    Zhu, Weifei; Chandrasekharan, Unni M; Bandyopadhyay, Smarajit; Morris, Sidney M; DiCorleto, Paul E; Kashyap, Vikram S

    2010-04-01

    Arterial thrombosis is a common disease leading to severe ischemia beyond the obstructing thrombus. Additionally, endothelial dysfunction at the site of thrombosis can be rescued by l-arginine supplementation or arginase blockade in several animal models. Exposure of rat aortic endothelial cells (RAECs) to thrombin upregulates arginase I mRNA and protein levels. In this study, we further investigated the molecular mechanism of thrombin-induced arginase changes in endothelial cells. Thrombin strikingly increased arginase I promoter and enzyme activity in primary cultured RAECs. Using different deletion and point mutations of the promoter, we demonstrated that the activating protein-1 (AP-1) consensus site located at -3,157 bp in the arginase I promoter was a thrombin-responsive element. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay further confirmed that upon thrombin stimulation, c-Jun and activating transcription factor-2 (ATF-2) bound to the AP-1 site, which initiated the transactivation. Moreover, loss-of-function studies using small interfering RNA confirmed that recruitment of these two transcription factors to the AP-1 site was required for thrombin-induced arginase upregulation. In the course of defining the signaling pathway leading to the activation of AP-1 by thrombin, we found thrombin-induced phosphorylation of stress-activated protein kinase/c-Jun-NH(2)-terminal kinase (SAPK/JNK or JNK1/2/3) and p38 mitogen-activated protein kinase, which were followed by the phosphorylation of both c-Jun and ATF-2. These findings reveal the basis for thrombin induction of endothelial arginase I and indicate that arginase inhibition may be an attractive therapeutic alternative in the setting of arterial thrombosis and its associated endothelial dysfunction. PMID:20032511

  15. Geniposide suppresses LPS-induced nitric oxide, PGE2 and inflammatory cytokine by downregulating NF-κB, MAPK and AP-1 signaling pathways in macrophages.

    PubMed

    Shi, Qinghai; Cao, Jinjun; Fang, Li; Zhao, Hongyan; Liu, Zhengxiang; Ran, Jihua; Zheng, Xinchuan; Li, Xiaoling; Zhou, Yu; Ge, Di; Zhang, Hongming; Wang, Li; Ran, Ying; Fu, Jianfeng

    2014-06-01

    Inflammatory responses are important to host immune reactions, but uncontrolled inflammatory mediators may aid in the pathogenesis of other inflammatory diseases. Geniposide, an iridoid glycoside found in the herb gardenia, is believed to have broad-spectrum anti-inflammatory effects in murine models but its mechanism of action is unclear. We investigated the action of this compound in murine macrophages stimulated by lipopolysaccharide (LPS), as the stimulation of macrophages by LPS is known to induce inflammatory reactions. We determined the effect of geniposide on LPS-induced production of the inflammatory mediators, nitric oxide (NO) and prostaglandin E2 (PGE2), the mRNA and protein expression of the NO and PGE2 synthases, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), respectively, and the mRNA and protein expression of the inflammatory cytokine, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Furthermore, nuclear factor (NF)-κB, mitogen-activated protein kinase (MAPK) and activator protein (AP)-1 activity were assayed. To understand the action of geniposide on the NF-κB and MAPK pathways, we studied the effect of NF-κB and MAPK inhibitors on the LPS-induced production of NO, PGE2 and TNF-α. Our findings clearly showed that geniposide mainly exerts its anti-inflammatory effects by inhibiting the LPS-induced NF-κB, MAPK and AP-1 signaling pathways in macrophages, which subsequently reduces overexpression of the inducible enzymes iNOS and COX-2 and suppresses the expression and release of the inflammatory factors, TNF-α, IL-6, NO and PGE2. Thus, geniposide shows promise as a therapeutic agent in inflammatory diseases. PMID:24735815

  16. NF-κB and AP-1 Connection: Mechanism of NF-κB-Dependent Regulation of AP-1 Activity

    PubMed Central

    Fujioka, Shuichi; Niu, Jiangong; Schmidt, Christian; Sclabas, Guido M.; Peng, Bailu; Uwagawa, Tadashi; Li, Zhongkui; Evans, Douglas B.; Abbruzzese, James L.; Chiao, Paul J.

    2004-01-01

    Nuclear factor κB (NF-κB) and activator protein 1 (AP-1) transcription factors regulate many important biological and pathological processes. Activation of NF-κB is regulated by the inducible phosphorylation of NF-κB inhibitor IκB by IκB kinase. In contrast, Fos, a key component of AP-1, is primarily transcriptionally regulated by serum responsive factors (SRFs) and ternary complex factors (TCFs). Despite these different regulatory mechanisms, there is an intriguing possibility that NF-κB and AP-1 may modulate each other, thus expanding the scope of these two rapidly inducible transcription factors. To determine whether NF-κB activity is involved in the regulation of fos expression in response to various stimuli, we analyzed activity of AP-1 and expression of fos, fosB, fra-1, fra-2, jun, junB, and junD, as well as AP-1 downstream target gene VEGF, using MDAPanc-28 and MDAPanc-28/IκBαM pancreatic tumor cells and wild-type, IKK1−/−, and IKK2−/− murine embryonic fibroblast cells. Our results show that elk-1, a member of TCFs, is one of the NF-κB downstream target genes. Inhibition of NF-κB activity greatly decreased expression of elk-1. Consequently, the reduced level of activated Elk-1 protein by extracellular signal-regulated kinase impeded constitutive, serum-, and superoxide-inducible c-fos expression. Thus, our study revealed a distinct and essential role of NF-κB in participating in the regulation of elk-1, c-fos, and VEGF expression. PMID:15314185

  17. Retinoic acid-induced AP-1 transcriptional activity regulates B16 mouse melanoma growth inhibition and differentiation.

    PubMed

    Huang, Ying; Boskovic, Goran; Niles, Richard M

    2003-02-01

    Retinoic acid (RA) inhibits growth and induces differentiation of B16 mouse melanoma cells. These effects are accompanied by a large increase in PKCalpha mRNA and protein levels and surprisingly an increase in activating protein-1 (AP-1) transcriptional activity. To further investigate the RA-induced AP-1 activity we established clones of B16 cells stably expressing an AP-1-luciferase reporter gene. Treatment of these clones with phorbol dibutyrate increased AP-1 activity which peaked at 2-4 h and returned to baseline level by 24 h. In contrast, RA treatment resulted in a slow increase in AP-1 activity that reached a maximum level at 48 h and was maintained for the duration of the treatment. We tested the importance of the RA-induced AP-1 activity by establishing clones which stably express a dominant negative fos gene (A-fos) and have greatly diminished AP-1 activity. Growth rates of untreated A-fos expressing cells were similar to wt B16 and clones not expressing A-fos. However, clones expressing the dominant-negative fos had a markedly decreased sensitivity to RA-induced inhibition of anchorage-dependent and -independent growth. Treatment of wt B16 cells for 48 h with RA increased melanin production by two to fourfold, but this effect was completely lost in the A-fos clones. The ability of RA to induce RARbeta and PKCalpha expression was retained in A-fos clones, suggesting that A-fos was not interfering with RAR transcription activation functions. We tested whether the RA-induced AP-1 activity might be mediated by the ERK1/2 MAPK pathway. Inhibition of ERK1/2 phosphorylation stimulated AP-1 activity, which was not additive to that induced by RA. This finding raises the possibility that this MAPK pathway may be a target of retinoid action. Our observations suggest that AP-1 transcriptional activity induced by RA likely plays an important role in the biological changes mediated by this retinoid in B16 melanoma cells. PMID:12494454

  18. 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.

  19. Youngiasides A and C Isolated from Youngia denticulatum Inhibit UVB-Induced MMP Expression and Promote Type I Procollagen Production via Repression of MAPK/AP-1/NF-κB and Activation of AMPK/Nrf2 in HaCaT Cells and Human Dermal Fibroblasts.

    PubMed

    Kim, Myungsuk; Park, Young Gyun; Lee, Hee-Ju; Lim, Sue Ji; Nho, Chu Won

    2015-06-10

    This study investigated the effects of youngiaside A (YA), youngiaside C (YC), and Youngia denticulatum extract (YDE) on extrinsic aging and assessed its molecular mechanisms in UVB-irradiated HaCaT keratinocytes and human dermal fibroblasts (HDFs). The results showed that YA, YC, and YDE decreased matrix metalloproteinase (MMP) expression and production in HaCaT cell and HDFs and increased collagen expression and production in HDFs. In addition, YA, YC, and YDE significantly increased antioxidant enzyme expression, thereby down-regulating UVB-induced reactive oxygen species (ROS) production and ROS-induced mitogen-activated protein kinase (MAPK) and activator protein-1 (AP-1) signaling in HaCaT cells. Furthermore, YA, YC, and YDE reduced phosphorylation of IκBα and IKKα/β, blocked nuclear factor-κB (NF-κB) p65 nuclear translocation, and strongly suppressed pro-inflammatory mediators. Finally, YA, YC, and YDE augmented UVB-induced adenosine monophosphate activated protein kinase (AMPK) phosphorylation and YA and YC did not inhibit MMP-1 production in AMPK inhibitor or nuclear factor-erythroid 2-related factor-2 (Nrf2) siRNA-treated HaCaT cells. The results suggest that these compounds could be potential therapeutic agents for prevention and treatment of skin photoaging. PMID:25994852

  20. AP-1 activity during normal human keratinocyte differentiation: evidence for a cytosolic modulator of AP-1/DNA binding.

    PubMed

    Briata, P; D'Anna, F; Franzi, A T; Gherzi, R

    1993-01-01

    Increased levels of c-fos and c-jun expression have been observed in differentiating epithelial cells. However, no data are available on activator protein 1 (AP-1) activity during keratinocyte differentiation. In this work we investigated c-fos and c-jun gene expression and AP-1-(12-O-tetradecanoylphorbol-13-acetate)-responsive enhancer element (TRE) binding activity during keratinocyte differentiation utilizing both authentic and in culture-reconstituted human epidermis. We demonstrate that: (i) in reconstituted epidermis, non-differentiated and differentiated keratinocytes express equivalent levels of c-Jun, while in reconstituted epidermis permanently grafted onto athymic mice, as well as in authentic epidermis, c-Jun is predominantly expressed in the granular layer of the tissue. Equivalent levels of c-fos expression have been found in all the layers of both reconstituted and authentic epidermis. (ii) Nuclear extracts from cultures enriched in differentiated keratinocytes display an 80-90% reduction of AP-1 activity when compared to extracts from cultures enriched in nondifferentiated cells. (iii) Cytosolic extracts obtained from cultures enriched in differentiated cells reduce, in a concentration-dependent manner, the AP-1 activity present in nuclear extracts of both mammalian and Drosophila cells. (iv) The specific TRE binding activity of a recombinant c-Jun protein is significantly reduced by cytosolic extracts of differentiated keratinocytes, while the specific DNA binding of the purified recombinant human homeoprotein HOX4B is not. (v) The dephosphorylation, by alkaline phosphatase, of cytosolic extracts increases the inhibitory activity already present or makes evident a latent activity. PMID:8416791

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

    PubMed Central

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

    2015-01-01

    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. PMID:26404494

  2. Japanese encephalitis virus induces matrix metalloproteinase-9 expression via a ROS/c-Src/PDGFR/PI3K/Akt/MAPKs-dependent AP-1 pathway in rat brain astrocytes

    PubMed Central

    2012-01-01

    Background Japanese encephalitis virus (JEV) infection is a major cause of acute encephalopathy in children, which destroys central nervous system (CNS) cells, including astrocytes and neurons. Matrix metalloproteinase (MMP)-9 has been shown to degrade components of the basal lamina, leading to disruption of the blood-brain barrier (BBB) and to contribute to neuroinflammatory responses in many neurological diseases. However, the detailed mechanisms of JEV-induced MMP-9 expression in rat brain astrocytes (RBA-1 cells) are largely unclear. Methods In this study, the effect of JEV on expression of MMP-9 was determined by gelatin zymography, western blot analysis, RT-PCR, and promoter assay. The involvement of AP-1 (c-Jun and c-Fos), c-Src, PDGFR, PI3K/Akt, and MAPKs in these responses were investigated by using the selective pharmacological inhibitors and transfection with siRNAs. Results Here, we demonstrate that JEV induces expression of pro-form MMP-9 via ROS/c-Src/PDGFR/PI3K/Akt/MAPKs-dependent, AP-1 activation in RBA-1 cells. JEV-induced MMP-9 expression and promoter activity were inhibited by pretreatment with inhibitors of AP-1 (tanshinone), c-Src (PP1), PDGFR (AG1296), and PI3K (LY294002), and by transfection with siRNAs of c-Jun, c-Fos, PDGFR, and Akt. Moreover, JEV-stimulated AP-1 activation was inhibited by pretreatment with the inhibitors of c-Src, PDGFR, PI3K, and MAPKs. Conclusion From these results, we conclude that JEV activates the ROS/c-Src/PDGFR/PI3K/Akt/MAPKs pathway, which in turn triggers AP-1 activation and ultimately induces MMP-9 expression in RBA-1 cells. These findings concerning JEV-induced MMP-9 expression in RBA-1 cells imply that JEV might play an important role in CNS inflammation and diseases. PMID:22251375

  3. Guanylyl cyclase/natriuretic peptide receptor-A signaling antagonizes the vascular endothelial growth factor-stimulated MAPKs and downstream effectors AP-1 and CREB in mouse mesangial cells

    PubMed Central

    Tripathi, Satyabha; Pandey, Kailash N.

    2012-01-01

    Along with its natriuretic, diuretic, and vasodilatory properties, atrial natriuretic peptide (ANP) and its guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) exhibit an inhibitory effect on cell growth and proliferation. However, the signaling pathways mediating this inhibition are not well understood. The objective of this study was to determine the effect of ANP-NPRA system on mitogen-activated protein kinases (MAPKs) and the downstream proliferative transcription factors involving activating protein-1 (AP-1) and cAMP-response element binding protein (CREB) in agonist-stimulated mouse mesangial cells (MMCs). We found that ANP inhibited vascular endothelial growth factor (VEGF)-stimulated phosphorylation of MAPKs (Erk1, Erk2, JNK, and p38), to a greater extent in NPRA-transfected cells (50–60%) relative to vector-transfected cells (25–30%). The analyses of the phosphorylated transcription factors revealed that ANP inhibited VEGF-stimulated activation of CREB, and the AP-1 subunits (c-jun and c-fos). Gel shift assays demonstrated that ANP inhibited VEGF-stimulated AP-1 and CREB DNA-binding ability by 67 % and 62 %, respectively. The addition of the protein kinase G (PKG) inhibitor, KT-5823, restored the VEGF-stimulated activation of MAPKs, AP-1, and CREB, demonstrating the integral role of cGMP/PKG signaling in NPRA-mediated effects. Our results delineate the under lying mechanisms through which ANP-NPRA system exerts an inhibitory effect on MAPKs and down-stream effector molecules, AP-1 and CREB, critical for cell growth and proliferation. PMID:22610792

  4. Hepatopoietin interacts directly with COP9 signalosome and regulates AP-1 activity.

    PubMed

    Wang, Yan; Lu, Chengrong; Wei, Handong; Wang, Na; Chen, Xiaoxiao; Zhang, Lingqiang; Zhai, Yun; Zhu, Yunping; Lu, Yinglin; He, Fuchu

    2004-08-13

    Hepatopoietin (HPO)/augmenter of liver regeneration (ALR) is a specific hepatotrophic growth factor, which plays a key role in liver regeneration. Our previous study indicated that HPO executes its function by an inter-reactive network of the autocrine, paracrine and endocrine pathways. Recently, we have demonstrated that intracellular HPO interacts with Jun activation domain-binding protein 1 (JAB1) and leads to potentiation of activating protein-1 (AP-1) activity in a MAPK independent fashion. JAB1 is the fifth subunit of the COP9 signalosome (CSN), which is first identified as a suppressor of plant morphogenesis. A protein complex kinase activity associated with the CSN has been reported but not identified yet. In this report, we investigated further the association of HPO with the whole CSN. HPO exists in a complex with the eight-component CSN, both when purified from glycerol gradient centrifugation and when reciprocal immunoprecipitated from the lysates of transfected COS-7 cells. Intracellular HPO colocalizes with endogenous CSN in nucleus of hepatic cells. In addition, intracellular function of HPO that increases the phosphorylation of c-Jun leading to potentiate the AP-1 activity is inhibited by curcumin, a potent inhibitor of CSN-associated kinase. Taken together, these results elucidate a novel relationship of intracellular growth factor, HPO with large protein complex, CSN, which suggests a possible linkage between CSN and liver regeneration. PMID:15304329

  5. The E3 ubiquitin ligase Trim7 mediates c-Jun/AP-1 activation by Ras signalling

    PubMed Central

    Chakraborty, Atanu; Diefenbacher, Markus E.; Mylona, Anastasia; Kassel, Olivier; Behrens, Axel

    2015-01-01

    The c-Jun/AP-1 transcription factor controls key cellular behaviours, including proliferation and apoptosis, in response to JNK and Ras/MAPK signalling. While the JNK pathway has been well characterised, the mechanism of activation by Ras was elusive. Here we identify the uncharacterised ubiquitin ligase Trim7 as a critical component of AP-1 activation via Ras. We found that MSK1 directly phosphorylates Trim7 in response to direct activation by the Ras–Raf–MEK–ERK pathway, and this modification stimulates Trim7 E3 ubiquitin ligase activity. Trim7 mediates Lys63-linked ubiquitination of the AP-1 coactivator RACO-1, leading to RACO-1 protein stabilisation. Consequently, Trim7 depletion reduces RACO-1 levels and AP-1-dependent gene expression. Moreover, transgenic overexpression of Trim7 increases lung tumour burden in a Ras-driven cancer model, and knockdown of Trim7 in established xenografts reduces tumour growth. Thus, phosphorylation-ubiquitination crosstalk between MSK1, Trim7 and RACO-1 completes the long sought-after mechanism linking growth factor signalling and AP-1 activation. PMID:25851810

  6. 5-Methoxyl Aesculetin Abrogates Lipopolysaccharide-Induced Inflammation by Suppressing MAPK and AP-1 Pathways in RAW 264.7 Cells.

    PubMed

    Wu, Lei; Li, Xueqin; Wu, Haifeng; Long, Wei; Jiang, Xiaojian; Shen, Ting; Qiang, Qian; Si, Chuanling; Wang, Xinfeng; Jiang, Yunyao; Hu, Weicheng

    2016-01-01

    For the first time, a pale amorphous coumarin derivative, 5-methoxyl aesculetin (MOA), was isolated from the dried bark of Fraxinus rhynchophylla Hance (Oleaceae). MOA modulates cytokine expression in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages, but the precise mechanisms are still not fully understood. We determined the effects of MOA on the production of inflammatory mediators and pro-inflammatory cytokines in the LPS-induced inflammatory responses of RAW 264.7 macrophages. MOA significantly inhibited the LPS-induced production of nitric oxide (NO), prostaglandin E₂ (PGE₂), tumor necrosis factor-α (TNF-α), interleukin-6, and interleukin-1β. It also effectively attenuated inducible nitric oxide (NO) synthase, cyclooxygenase-2, and TNF-α mRNA expression and significantly decreased the levels of intracellular reactive oxygen species. It inhibited phosphorylation of the extracellular signal-regulated kinase (ERK1/2), thus blocking nuclear translocation of activation protein (AP)-1. In a molecular docking study, MOA was shown to target the binding site of ERK via the formation of three hydrogen bonds with two residues of the kinase, which is sufficient for the inhibition of ERK. These results suggest that the anti-inflammatory effects of MOA in RAW 264.7 macrophages derive from its ability to block both the activation of mitogen-activated protein kinases (MAPKs) and one of their downstream transcription factors, activator protein-1 (AP-1). Our observations support the need for further research into MOA as a promising therapeutic agent in inflammatory diseases. PMID:26938526

  7. 5-Methoxyl Aesculetin Abrogates Lipopolysaccharide-Induced Inflammation by Suppressing MAPK and AP-1 Pathways in RAW 264.7 Cells

    PubMed Central

    Wu, Lei; Li, Xueqin; Wu, Haifeng; Long, Wei; Jiang, Xiaojian; Shen, Ting; Qiang, Qian; Si, Chuanling; Wang, Xinfeng; Jiang, Yunyao; Hu, Weicheng

    2016-01-01

    For the first time, a pale amorphous coumarin derivative, 5-methoxyl aesculetin (MOA), was isolated from the dried bark of Fraxinus rhynchophylla Hance (Oleaceae). MOA modulates cytokine expression in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages, but the precise mechanisms are still not fully understood. We determined the effects of MOA on the production of inflammatory mediators and pro-inflammatory cytokines in the LPS-induced inflammatory responses of RAW 264.7 macrophages. MOA significantly inhibited the LPS-induced production of nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), interleukin-6, and interleukin-1β. It also effectively attenuated inducible nitric oxide (NO) synthase, cyclooxygenase-2, and TNF-α mRNA expression and significantly decreased the levels of intracellular reactive oxygen species. It inhibited phosphorylation of the extracellular signal-regulated kinase (ERK1/2), thus blocking nuclear translocation of activation protein (AP)-1. In a molecular docking study, MOA was shown to target the binding site of ERK via the formation of three hydrogen bonds with two residues of the kinase, which is sufficient for the inhibition of ERK. These results suggest that the anti-inflammatory effects of MOA in RAW 264.7 macrophages derive from its ability to block both the activation of mitogen-activated protein kinases (MAPKs) and one of their downstream transcription factors, activator protein-1 (AP-1). Our observations support the need for further research into MOA as a promising therapeutic agent in inflammatory diseases. PMID:26938526

  8. 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

  9. Curcumin Nanoparticles Ameliorate ICAM-1 Expression in TNF-α-Treated Lung Epithelial Cells through p47 phox and MAPKs/AP-1 Pathways

    PubMed Central

    Yang, Chuen-Mao; Liang, Chan-Jung; Lin, Chun-Ching; Chiang, Yao-Chang; Lee, Hui-Chun; Ko, Horng-Huey; Lee, Chiang-Wen

    2013-01-01

    Upregulation of intercellular adhesion molecule-1 (ICAM-1) involves adhesions between both circulating and resident leukocytes and the human lung epithelial cells during lung inflammatory reactions. We have previously demonstrated that curcumin-loaded polyvinylpyrrolidone nanoparticles (CURN) improve the anti-inflammatory and anti-oxidative properties of curcumin in hepatocytes. In this study, we focused on the effects of CURN on the expression of ICAM-1 in TNF-α-treated lung epithelial cells and compared these to the effects of curcumin water preparation (CURH). TNF-αinduced ICAM-1 expression, ROS production, and cell-cell adhesion were significantly attenuated by the pretreatment with antioxidants (DPI, APO, or NAC) and CURN, but not by CURH, as revealed by western blot analysis, RT-PCR, promoter assay, and ROS detection and adhesion assay. In addition, treatment of TNF-α-treated cells with CURN and antioxidants also resulted in an inhibition of activation of p47 phox and phosphorylation of MAPKs, as compared to that using CURH. Our findings also suggest that phosphorylation of MAPKs may eventually lead to the activation of transcription factors. We also observed that the effects of TNF-α treatment for 30 min, which includes a significant increase in the binding activity of AP-1 and phosphorylation of c-jun and c-fos genes, were reduced by CURN treatment. In vivo studies have revealed that CURN improved the anti-inflammation activities of CURH in the lung epithelial cells of TNF-α-treated mice. Our results indicate that curcumin-loaded polyvinylpyrrolidone nanoparticles may potentially serve as an anti-inflammatory drug for the treatment of respiratory diseases. PMID:23671702

  10. The p38 SAPK pathway regulates the expression of the MMP-9 collagenase via AP-1-dependent promoter activation.

    PubMed

    Simon, C; Simon, M; Vucelic, G; Hicks, M J; Plinkert, P K; Koitschev, A; Zenner, H P

    2001-12-10

    The invasive phenotype of cancers critically depends on the expression of proteases such as the M(R) 92,000 type IV collagenase (MMP-9). Several growth factors and oncogenes were found to increase promoter activity and as a consequence protease expression. This frequently requires the activation of the transcription factor AP-1 by signal transduction cascades such as the ERK and JNK pathways. We have previously demonstrated that the tumor promoter TPA can induce MMP-9 expression via a third signaling cascade, the p38 pathway. Considering that TPA is a potent activator of AP-1, we hypothesized that this transcription factor might also be required for p38 pathway-dependent MMP-9 regulation. While dominant negative p38 and MKK-6 mutants reduced MMP-9 promoter activity in CAT assays, a construct encoding an activating mutation in the MKK-6 protein potently stimulated it. This was mediated via 144 bp of the 5'flanking region of the wild-type promoter, which contains an AP-1 site at -79. Both point mutations in this motif and the expression of a c-jun protein lacking its transactivation domain and therefore acting as a dominant negative AP-1 mutant abrogated MKK-6-dependent promoter stimulation. Finally SB 203580, a specific p38 pathway inhibitor, reduced MMP-9 expression/secretion and in vitro invasion of cancer cells. Thus, our results provide evidence that also the third SAPK/MAPK signaling cascade, the p38 signal transduction pathway, stimulates MMP-9 expression in an AP-1-dependent fashion. PMID:11716547

  11. Suppression of albumin enhancer activity by H-ras and AP-1 in hepatocyte cell lines.

    PubMed Central

    Hu, J; Isom, H C

    1994-01-01

    We demonstrated, using a transient transfection assay, that the albumin enhancer increased the expression of the albumin promoter in a highly differentiated, simian virus 40 (SV40)-immortalized hepatocyte cell line, CWSV1, but was not functional in two ras-transformed cell lines (NR3 and NR4) derived from CWSV1 by stable transfection with the T24ras oncogene. A transient cotransfection assay showed that T24ras and normal c-Ha-ras were each able to inhibit the activity of the albumin enhancer in an immortal hepatocyte cell line. DNase I footprinting and gel mobility shift assays demonstrated that the DNA binding activities specific to the albumin enhancer were not decreased in the ras-transformed cells. ras also did not diminish the expression of HNF1 alpha, C/EBP alpha, HNF3 alpha, HNF3 beta, or HNF3 gamma but did significantly increase AP-1 binding activity. Three AP-1 binding sites were identified within the albumin enhancer, and DNA binding activities specific to these AP-1 sites were induced in the ras-transformed hepatocytes. Subsequent functional assays showed that overexpression of c-jun and c-fos inhibited the activity of the albumin enhancer. Site-directed mutagenesis of the AP-1 binding sites in the albumin enhancer partially abrogated the suppressing effect of ras and c-jun/c-fos on the enhancer. These functional studies therefore supported the results of the structural studies with AP-1. We conclude that the activity of the albumin enhancer is subject to regulation by ras signaling pathways and that the effect of ras on the albumin enhancer activity may be mediated by AP-1. Images PMID:8114691

  12. Modulation of AP-1 activity by the human progesterone receptor in endometrial adenocarcinoma cells.

    PubMed Central

    Bamberger, A M; Bamberger, C M; Gellersen, B; Schulte, H M

    1996-01-01

    The composite transcription factor activating protein 1 (AP-1) integrates various mitogenic signals in a large number of cell types, and is therefore a major regulator of cell proliferation. In the normal human endometrium, proliferation and differentiation alternate in a cyclic fashion, with progesterone being largely implicated in the latter process. However, the effects of progesterone and the progesterone receptor (hPR) on AP-1 activity in the human endometrium are not known. To address this issue, HEC-1-B endometrial adenocarcinoma cells, which are devoid of hPR, were transfected with luciferase reporter constructs driven by two different AP-1-dependent promoters. Unexpectedly, cotransfection of hPR caused a marked induction of luciferase activity in the absence of ligand on both promoters. The magnitude of this induction was similar to that observed in response to the phorbol ester TPA. Addition of ligand reversed the stimulating effect of the unliganded hPR on AM activity in these cells. These effects were specific for hPR, and were not observed with either human estrogen receptor or human glucocorticoid receptor. Furthermore, they strictly depended on the presence of AP-1-responsive sequences within target promoters. Finally, the described effects of hPR on AP-1 activity were shown to be cell-type specific, because they could not be demonstrated in SKUT-1-B, JEG-3, and COS-7 cells. To our knowledge this is the first report of an unliganded steroid receptor stimulating AP-1 activity. This effect and its reversal in the presence of ligand suggest a novel mechanism, through which hPR can act as a key regulator of both proliferation and differentiation in the human endometrium. PMID:8650238

  13. Eugenolol and glyceryl-isoeugenol suppress LPS-induced iNOS expression by down-regulating NF-kappaB AND AP-1 through inhibition of MAPKS and AKT/IkappaBalpha signaling pathways in macrophages.

    PubMed

    Yeh, J L; Hsu, J H; Hong, Y S; Wu, J R; Liang, J C; Wu, B N; Chen, I J; Liou, S F

    2011-01-01

    Eugenol and isoeugenol, two components of clover oil, have been reported to possess several biomedical properties, such as anti-inflammatory, antimicrobial and antioxidant effects. This study aims to examine the anti-inflammatory effects of eugenol, isoeugenol and four of their derivatives on expression of inducible nitric oxide synthase (iNOS) activated by lipopolysaccharide (LPS) in mouse macrophages (RAW 264.7), and to investigate molecular mechanisms underlying these effects. We found that two derivatives, eugenolol and glyceryl-isoeugenol, had potent inhibitory effects on LPS-induced upregulation of nitrite levels, iNOS protein and iNOS mRNA. In addition, they both suppressed the release of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) induced by LPS. Moreover, they both attenuated the DNA binding of NF-kB and AP-1, phosphorylation of inhibitory kB-alpha (IkB-alpha), and nuclear translocation of p65 protein induced by LPS. Finally, we demonstrated that glyceryl-isoeugenol suppressed the phosphorylation of ERK1/2, JNK and p38 MAPK, whereas eugenolol suppressed the phosphorylation of ERK1/2 and p38 MAPK. Taken together, these results suggest that that eugenolol and glyceryl-isoeugenol suppress LPS-induced iNOS expression by down-regulating NF-kB and AP-1 through inhibition of MAPKs and Akt/IkB-alpha signaling pathways. Thus, this study implies that eugenolol and glyceryl-isoeugenol may provide therapeutic benefits for inflammatory diseases. PMID:21658309

  14. 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...

  15. o,p'-DDT induces cyclooxygenase-2 gene expression in murine macrophages: Role of AP-1 and CRE promoter elements and PI3-kinase/Akt/MAPK signaling pathways

    SciTech Connect

    Han, Eun Hee; Kim, Ji Young; Kim, Hyung-Kyun; Hwang, Yong Pil; Jeong, Hye Gwang

    2008-12-01

    Dichlorodiphenyltrichloroethane (DDT) has been used as an insecticide to prevent the devastation of malaria in tropical zones. However, many reports suggest that DDT may act as an endocrine disruptor and may have possible carcinogenic effects. Cyclooxygenase-2 (COX-2) acts as a link between inflammation and carcinogenesis through its involvement in tumor promotion. In the present study, we examined the effect of o,p'-DDT on COX-2 gene expression and analyzed the molecular mechanism of its activity in murine RAW 264.7 macrophages. Exposure to o,p'-DDT markedly enhanced the production of prostaglandin E{sub 2} (PGE{sub 2}), a major COX-2 metabolite, in murine macrophages. Furthermore, o,p'-DDT dose-dependently increased the levels of COX-2 protein and mRNA. Transfection with human COX-2 promoter construct, electrophoretic mobility shift assays and DNA-affinity protein-binding assay experiments revealed that o,p'-DDT activated the activator protein 1 (AP-1) and cyclic AMP response element (CRE) sites, but not the NF-{kappa}B site. Phosphatidylinositol 3 (PI3)-kinase, its downstream signaling molecule, Akt, and mitogen-activated protein kinases (MAPK) were also significantly activated by the o,p'-DDT-induced AP-1 and CRE activation. These results demonstrate that o,p'-DDT induced COX-2 expression via AP-1 and CRE activation through the PI3-K/Akt/ERK, JNK, and p38 MAP kinase pathways. These findings provide further insight into the signal transduction pathways involved in the carcinogenic effects of o,p'-DDT.

  16. YY1 represses human papillomavirus type 16 transcription by quenching AP-1 activity.

    PubMed Central

    O'Connor, M J; Tan, S H; Tan, C H; Bernard, H U

    1996-01-01

    YY1 is a multifunctional transcription factor that has been shown to regulate the expression of a number of cellular and viral genes, including the human papillomavirus (HPV) oncogenes E6 and E7. In this study, we have analyzed the YY1-mediated repression of the HPV type 16 (HPV-16) E6-E7 promoter. A systematic analysis to identify YY1 sites present in the HPV-16 long control region showed that of 30 potential YY1 binding motifs, 24 bound purified recombinant YY1 protein, but only 10 of these were able to bind YY1 when nuclear extracts of HeLa cells were used. Of these, only a cluster of five sites, located in the vicinity of an AP-1 motif, were found to be responsible for repressing the HPV-16 P97 promoter. All five sites were required for repression, the mutation of any one site giving rise to a four- to sixfold increase in transcriptional activity. The target for YY1-mediated repression was identified as being a highly conserved AP-1 site, and we propose that AP-1 may represent a common target for YY1 repression. We also provide data demonstrating that YY1 can bind the transcriptional coactivator CREB-binding protein and propose a potentially novel mechanism by which YY1 represses AP-1 activity as a result of this YY1-CREB-binding protein interaction. PMID:8794287

  17. Apocynin increases glutathione synthesis and activates AP-1 in alveolar epithelial cells.

    PubMed

    Lapperre, T S; Jimenez, L A; Antonicelli, F; Drost, E M; Hiemstra, P S; Stolk, J; MacNee, W; Rahman, I

    1999-01-25

    Apocynin (4-hydroxy-3-methoxy-acetophenone) is a potent intracellular inhibitor of superoxide anion production in neutrophils. In this study, we studied the effect of apocynin on the regulation of the antioxidant glutathione (GSH) and activation of the transcription factor AP-I in human alveolar epithelial cells (A549). Apocynin enhanced intracellular GSH by increasing gamma-glutamylcysteine synthetase activity in A549 cells. Apocynin also increased the expression of gamma-GCS heavy subunit mRNA. This was associated with increased AP-1 DNA binding as measured by the electrophoretic mobility shift assay. These data indicate that apocynin displays antioxidant properties, in part, by increasing glutathione synthesis through activation of AP-1. PMID:9989612

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

    PubMed

    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

  19. 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

  20. The expression of the β-defensins hBD-2 and hBD-3 is differentially regulated by NF-κB and MAPK/AP-1 pathways in an in vitro model of Candida esophagitis

    PubMed Central

    Steubesand, Nadine; Kiehne, Karlheinz; Brunke, Gabriele; Pahl, Rene; Reiss, Karina; Herzig, Karl-Heinz; Schubert, Sabine; Schreiber, Stefan; Fölsch, Ulrich R; Rosenstiel, Philip; Arlt, Alexander

    2009-01-01

    Background Candida albicans resides on epithelial surfaces as part of the physiological microflora. However, under certain conditions it may cause life-threatening infections like Candida sepsis. Human β-defensins (hBDs) are critical components of host defense at mucosal surfaces and we have recently shown that hBD-2 and hBD-3 are upregulated in Candida esophagitis. We therefore studied the role of Candidate signalling pathways in order to understand the mechanisms involved in regulation of hBD-expression by C. albicans. We used the esophageal cell line OE21 and analysed the role of paracrine signals from polymorphonuclear leukocytes (PMN) in an in vitro model of esophageal candidiasis. Results Supernatants of C. albicans or indirect coculture with C. albicans induces upregulation of hBD-2 and hBD-3 expression. PMNs strongly amplifies C. albicans-mediated induction of hBDs. By EMSA we demonstrate that C. albicans activates NF-κB and AP-1 in OE21 cells. Inhibition of these pathways revealed that hBD-2 expression is synergistically regulated by both NF-κB and AP-1. In contrast hBD-3 expression is independent of NF-κB and relies solely on an EGFR/MAPK/AP-1-dependent pathway. Conclusion Our analysis of signal transduction events demonstrate a functional interaction of epithelial cells with PMNs in response to Candida infection involving divergent signalling events that differentially govern hBD-2 and hBD-3 expression. PMID:19523197

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

    PubMed Central

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

    2013-01-01

    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. PMID:23293292

  2. 2,3,5,6-Tetramethylpyrazine (TMP) down-regulated arsenic-induced heme oxygenase-1 and ARS2 expression by inhibiting Nrf2, NF-κB, AP-1 and MAPK pathways in human proximal tubular cells.

    PubMed

    Gong, Xuezhong; Ivanov, Vladimir N; Hei, Tom K

    2016-09-01

    Our recent study demonstrated that sodium arsenite at a clinically relevant dose induced nephrotoxicity in human renal proximal tubular epithelial cell line HK-2, which could be inhibited by natural product 2,3,5,6-tetramethylpyrazine (TMP) with antioxidant activity. The present study demonstrated that arsenic exposure resulted in protein and enzymatic induction of heme oxygenase-1 (HO-1) in dose- and time-dependent manners in HK-2 cells. Blocking HO-1 enzymatic activity by zinc protoporphyrin (ZnPP) augmented arsenic-induced apoptosis, ROS production and mitochondrial dysfunction, suggesting a critical role for HO-1 as a renal protectant in this procession. On the other hand, TMP, upstream of HO-1, inhibited arsenic-induced ROS production and ROS-dependent HO-1 expression. TMP also prevented mitochondria dysfunction and suppressed activation of the intrinsic apoptotic pathway in HK-2 cells. Our results revealed that the regulation of arsenic-induced HO-1 expression was performed through multiple ROS-dependent signal pathways and the corresponding transcription factors, including p38 MAPK and JNK (but not ERK), AP-1, Nrf2 and NF-κB. TMP inhibited arsenic-induced activations of JNK, p38 MAPK, ERK, AP-1 and Nrf2 and block HO-1 protein expression. The present study, furthermore, demonstrated arsenic-induced expression of arsenic response protein 2 (ARS2) that was regulated by p38 MAPK, ERK and NF-κB. To our knowledge, this is the first report showing that ARS2 involved in arsenic-induced nephrotoxicity, while TMP pretreatment prevented such an up-regulation of ARS2 in HK-2 cells. Given ARS2 and HO-1 sharing the similar regulation mechanism, we speculated that ARS2 might also mediate cell survival in this procession. In summary, our study highlighted a role of HO-1 in the protection against arsenic-induced cytotoxicity downstream from the primary targets of TMP and further indicated that TMP may be used as a potential therapeutic agent in the treatment of arsenic

  3. Activation of mitogen-activated protein kinases and AP-1 transcription factor in ovotoxicity induced by 4-vinylcyclohexene diepoxide in rats.

    PubMed

    Hu, Xiaoming; Flaws, Jodi A; Sipes, I Glenn; Hoyer, Patricia B

    2002-09-01

    Previous studies have demonstrated that ovotoxicity induced in small preantral (primordial and primary) ovarian follicles by 4-vinylcyclohexene diepoxide (VCD) in rats is likely via acceleration of the normal process of atresia (apoptosis). This acceleration is associated with increased activities of caspase cascades, changes in subcellular distribution of Bcl-2 family members, and alteration of estrogen receptor-mediated signaling pathways. The present study was designed to investigate possible effects of VCD dosing on the mitogen-activated protein kinases (MAPK)/AP-1 signaling pathways in rat ovarian small follicles. Female F344 rats were given a single dose of VCD (80 mg/kg i.p., 1 day--a time when ovotoxicity has not been initiated) or dosed daily for 10 or 15 days (80 mg/kg i.p.; 10 days--a time when the earliest signs of impending follicular destruction is seen, 15 days--a time when significant ovotoxicity is underway). Four hours following the final dose, ovaries and livers were collected. Ovarian small (25-100 microm) and large (100-250 microm) preantral follicles were isolated, and cytosolic or nuclear extracts were prepared from follicles and livers for analyses. Activities of MAPKs, including extracellular signal-regulated kinase, c-Jun N-terminal protein kinase (JNK), and p38 kinase, were determined in follicular and liver cytosolic extracts, and AP-1 DNA binding activity was determined in follicular and liver nuclear extracts. Compared with control, a single dose of VCD caused a decrease in JNK activity and an increase of AP-1 binding activity in isolated small ovarian follicles. After repeated daily dosing with VCD for 10 or 15 days, JNK and p38 kinase activities in small ovarian follicles were increased (p38 kinase: 1.64 +/- 0.14 for 10 days, 1.48 +/- 0.11 for 15 days, VCD/control, P < 0.01; JNK: 1.44 +/- 0.11 for 10 days, 1.37 +/- 0.06 for 15 days, VCD/control, P < 0.01) and AP-1 binding activity in small ovarian follicles was decreased (10 days, 0

  4. Exogenous avian leukosis virus-induced activation of the ERK/AP1 pathway is required for virus replication and correlates with virus-induced tumorigenesis

    PubMed Central

    Dai, Manman; Feng, Min; Ye, Yu; Wu, Xiaochan; Liu, Di; Liao, Ming; Cao, Weisheng

    2016-01-01

    A proteomics approach was used to reveal the up-regulated proteins involved in the targeted mitogen-activated protein kinase (MAPK) signal transduction pathway in DF-1 cells after ALV subgroup J (ALV-J) infection. Next, we found that ALV-J CHN06 strain infection of DF-1 cells correlated with extracellular signal-regulated kinase 2 (ERK2) activation, which was mainly induced within 15 min, a very early stage of infection, and at a late infection stage, from 108 h to 132 h post-infection. Infection with other ALV subgroup (A/B) strains also triggered ERK/MAPK activation. Moreover, when activating ERK2, ALV subgroups A, B and J simultaneously induced the phosphorylation of c-Jun, an AP1 family member and p38 activation but had no obvious effect on JNK activation at either 15 min or 120 h. Interestingly, only PD98059 inhibited the ALV-induced c-Jun phosphorylation while SP600125 or SB203580 had no influence on c-Jun activation. Furthermore, the viral gp85 and gag proteins were found to contribute to ERK2/AP1 activation. Additionally, the specific ERK inhibitor, PD980509, significantly suppressed ALV replication, as evidenced by extremely low levels of ALV promoter activity and ALV-J protein expression. In vivo analysis of ERK2 activation in tumor cells derived from ALV-J-infected chicken demonstrated a strong correlation between ERK/MAPK activation and virus-associated tumorigenesis. PMID:26754177

  5. Ramalin inhibits VCAM-1 expression and adhesion of monocyte to vascular smooth muscle cells through MAPK and PADI4-dependent NF-kB and AP-1 pathways.

    PubMed

    Park, Bongkyun; Yim, Joung-Han; Lee, Hong-Kum; Kim, Byung-Oh; Pyo, Suhkneung

    2015-01-01

    Cell adhesion molecules play a critical role in inflammatory processes and atherosclerosis. In this study, we investigated the effect of ramalin, a chemical compound from the Antarctic lichen Ramalina terebrata, on vascular cell adhesion molecule-1 (VCAM-1) expression induced by TNF-α in vascular smooth muscular cells (VSMCs). Pretreatment of VSMCs with ramalin (0.1-10 μg/mL) concentration-dependently inhibited TNF-α-induced VCAM-1 expression. Additionally, ramalin inhibited THP-1 (human acute monocytic leukemia cell line) cell adhesion to TNF-α-stimulated VSMCs. Ramalin suppressed TNF-α-induced production of reactive oxygen species (ROS), PADI4 expression, and phosphorylation of p38, ERK, and JNK. Moreover, ramalin inhibited TNF-α-induced translocation of NF-κB and AP-1. Inhibition of PADI4 expression by small interfering RNA or the PADI4-specific inhibitor markedly attenuated TNF-α-induced activation of NF-κB and AP-1 and VCAM-1 expression in VSMCs. Our study provides insight into the mechanisms underlying ramalin activity and suggests that ramalin may be a potential therapeutic agent to modulate inflammation within atherosclerosis. PMID:25494680

  6. Interleukin 1β and tumor necrosis factor α promote hFOB1.19 cell viability via activating AP1

    PubMed Central

    Ying, Hongliang; Li, Qiang; Zhao, Changfu

    2016-01-01

    Bone trauma healing is a complex physiological process, which may involve the function of various inflammatory cytokines. Our study aimed to explore the roles of inflammatory cytokines in bone trauma healing and reveal the potential mechanism. Concentrations of interleukin (IL)-6, IL-1β and tumor necrosis factor alpha (TNF-α) in peripheral blood serum of bone trauma patients after surgery were determined by ELISA. The human osteoblast hFOB1.19 cell line was cultured to determine the effect of these cytokines in cell viability using MTT assay. In addition, luciferase reporter assay was performed to investigate the activator protein 1 (AP1) transcriptional activity, and small interfering RNA was transfected to inhibit FOS, a component of AP1 molecule. IL-6, IL-1β and TNF-α exhibited higher level in patients with more severe bone traumas after surgery. IL-1β and TNF-α, but not IL-6, induced a significant increase of hFOB1.19 viability after three days of treatment (P < 0.05). IL-1β and TNF-α could activate AP1 transcriptional activity in hFOB1.19 cells (P < 0.001), but the activation was inhibited when cells were pretreated with inhibitor of JNKs, SP600125 (P < 0.001). Besides, the effect of IL-1β and TNF-α on promoting viability was significantly inhibited after knockdown of FOS. These findings indicated that IL-1β and TNF-α played an important role in promoting osteoblast viability via the activation of AP1 transcriptional activity, which was likely to involve the JNK/MAPK signaling pathway. Modulating inflammatory cytokines is a potential strategy for improving the outcome of bone trauma healing. PMID:27347349

  7. Apigenin-7-O-β-D-glucuronide inhibits LPS-induced inflammation through the inactivation of AP-1 and MAPK signaling pathways in RAW 264.7 macrophages and protects mice against endotoxin shock.

    PubMed

    Hu, Weicheng; Wang, Xinfeng; Wu, Lei; Shen, Ting; Ji, Lilian; Zhao, Xihong; Si, Chuan-Ling; Jiang, Yunyao; Wang, Gongcheng

    2016-02-01

    Apigenin-7-O-β-D-glucuronide (AG), an active flavonoid derivative isolated from the agricultural residue of Juglans sigillata fruit husks, possesses multiple pharmacological activities, including anti-oxidant, anti-complement, and aldose reductase inhibitory activities. To date, no report has identified the anti-inflammatory mechanisms of AG. This study was therefore designed to characterize the molecular mechanisms of AG on lipopolysaccharide (LPS)-induced inflammatory cytokines in RAW 264.7 cells and on endotoxin-induced shock in mice. AG suppressed the release of nitric oxide (NO), prostaglandin E2 (PGE2), and tumour necrosis factor-α (TNF-α) in LPS-stimulated RAW 264.7 macrophages in a dose-dependent manner without affecting cell viability. Additionally, AG suppressed LPS-induced mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and TNF-α. AG treatment decreased the translocation of c-Jun into the nucleus, and decreased activator protein-1 (AP-1)-mediated luciferase activity through the inhibition of both p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) phosphorylation. Consistent with the in vitro observations, AG protected mice from LPS-induced endotoxin shock by inhibiting proinflammatory cytokine production. Taken together, these results suggest that AG may be used as a source of anti-inflammatory agents as well as a dietary complement for health promotion. PMID:26750400

  8. Synthetic glucocorticoids that dissociate transactivation and AP-1 transrepression exhibit antiinflammatory activity in vivo.

    PubMed

    Vayssière, B M; Dupont, S; Choquart, A; Petit, F; Garcia, T; Marchandeau, C; Gronemeyer, H; Resche-Rigon, M

    1997-08-01

    Some of the most potent antiinflammatory and immunosuppressive agents are synthetic glucocorticoids. However, major side effects severely limit their therapeutic use. The development of improved glucocorticoid-based drugs will require the separation of beneficial from deleterious effects. One possibility toward this goal is to try to dissociate two main activities of glucocorticoids, i.e. transactivation and transrepression. Screening of a library of compounds using transactivation and AP-1 transrepression models in transiently transfected cells identified dissociated glucocorticoids, which exert strong AP-1 inhibition but little or no transactivation. Importantly, despite high ligand binding affinity, the prototypic dissociated compound, RU24858, acted as a weak agonist and did not efficiently antagonize dexamethasone-induced transcription in transfected cells. Similar results were obtained in hepatic HTC cells for the transactivation of the endogenous tyrosine amino transferase gene (TAT), which encodes one of the enzymes involved in the glucocorticoid-dependent stimulation of neoglucogenesis. To investigate whether dissociated glucocorticoids retained the antiinflammatory and immunosuppressive potential of classic glucocorticoids, several in vitro and in vivo models were used. Indeed, secretion of the proinflammatory lymphokine interleukin-1beta was severely inhibited by dissociated glucocorticoids in human monocytic THP 1 cells. Moreover, in two in vivo models, these compounds exerted an antiinflammatory and immunosuppressive activity as potent as that of the classic glucocorticoid prednisolone. These results may lead to an improvement of antiinflammatory and immunosuppressive therapies and provide a novel concept for drug discovery. PMID:9259316

  9. 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.

  10. Transcription factor AP-1 in esophageal squamous cell carcinoma: Alterations in activity and expression during Human Papillomavirus infection

    PubMed Central

    2009-01-01

    Background Esophageal squamous cell carcinoma (ESCC) is a leading cause of cancer-related deaths in Jammu and Kashmir (J&K) region of India. A substantial proportion of esophageal carcinoma is associated with infection of high-risk HPV type 16 and HPV18, the oncogenic expression of which is controlled by host cell transcription factor Activator Protein-1 (AP-1). We, therefore, have investigated the role of DNA binding and expression pattern of AP-1 in esophageal cancer with or without HPV infection. Methods Seventy five histopathologically-confirmed esophageal cancer and an equal number of corresponding adjacent normal tissue biopsies from Kashmir were analyzed for HPV infection, DNA binding activity and expression of AP-1 family of proteins by PCR, gel shift assay and immunoblotting respectively. Results A high DNA binding activity and elevated expression of AP-1 proteins were observed in esophageal cancer, which differed between HPV positive (19%) and HPV negative (81%) carcinomas. While JunB, c-Fos and Fra-1 were the major contributors to AP-1 binding activity in HPV negative cases, Fra-1 was completely absent in HPV16 positive cancers. Comparison of AP-1 family proteins demonstrated high expression of JunD and c-Fos in HPV positive tumors, but interestingly, Fra-1 expression was extremely low or nil in these tumor tissues. Conclusion Differential AP-1 binding activity and expression of its specific proteins between HPV - positive and HPV - negative cases indicate that AP-1 may play an important role during HPV-induced esophageal carcinogenesis. PMID:19758438

  11. Saponins from the roots of Platycodon grandiflorum suppress ultraviolet A-induced matrix metalloproteinase-1 expression via MAPKs and NF-κB/AP-1-dependent signaling in HaCaT cells.

    PubMed

    Hwang, Yong Pil; Kim, Hyung Gyun; Choi, Jae Ho; Han, Eun Hee; Kwon, Kwang-Il; Lee, Young Chun; Choi, Jun Min; Chung, Young Chul; Jeong, Tae Cheon; Jeong, Hye Gwang

    2011-12-01

    Saponins from the roots of Platycodon grandiflorum (CKS) have been shown to exhibit many pharmacological activities, including anti-cancer and anti-inflammatory activities and antioxidant effects. However, anti-skin photoaging effects of CKS have not yet been reported. In this study, we investigated the protective effects of CKS against UVA damage on immortalized human keratinocytes (HaCaT). We then explored the inhibitory effects of CKS on UVA-induced MMP-1 and investigated the molecular mechanism underlying those effects. CKS increased the cell viability and inhibited reactive oxygen species (ROS) production in HaCaT cells exposed to UVA irradiation. Pre-treatment of HaCaT cells with CKS inhibited UVA-induced production of MMP-1 and MMP-9. In addition, CKS decreased UVA-induced expression of the inflammatory cytokines IL-1β and IL-6. Western blot analysis further revealed that CKS markedly suppressed the enhancement of collagen degradation in UVA-exposed HaCaT cells. CKS also suppressed UVA-induced activation of NF-κB or c-Jun and c-Fos, and the phosphorylation of MAPKs, which are upstream modulators of NF-κB and AP-1. PMID:22005258

  12. 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.

  13. 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

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

    PubMed

    Shen, Ting; Yang, Woo Seok; Yi, Young-Su; 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) I κ B kinase ε (IKK ε )/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

  15. Omega 3 but not omega 6 fatty acids inhibit AP-1 activity and cell transformation in JB6 cells

    PubMed Central

    Liu, Guangming; Bibus, Douglas M.; Bode, Ann M.; Ma, Wei-Ya; Holman, Ralph T.; Dong, Zigang

    2001-01-01

    Epidemiological and animal-based investigations have indicated that the development of skin cancer is in part associated with poor dietary practices. Lipid content and subsequently the derived fatty acid composition of the diet are believed to play a major role in the development of tumorigenesis. Omega 3 (ω3) fatty acids, including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), can effectively reduce the risk of skin cancer whereas omega 6 (ω6) fatty acids such as arachidonic acid (AA) reportedly promote risk. To investigate the effects of fatty acids on tumorigenesis, we performed experiments to examine the effects of the ω3 fatty acids EPA and DHA and of the ω6 fatty acid AA on phorbol 12-tetradecanoate 13-acetate (TPA)-induced or epidermal growth factor (EGF)-induced transcription activator protein 1 (AP-1) transactivation and on the subsequent cellular transformation in a mouse epidermal JB6 cell model. DHA treatment resulted in marked inhibition of TPA- and EGF-induced cell transformation by inhibiting AP-1 transactivation. EPA treatment also inhibited TPA-induced AP-1 transactivation and cell transformation but had no effect on EGF-induced transformation. AA treatment had no effect on either TPA- or EGF-induced AP-1 transactivation or transformation, but did abrogate the inhibitory effects of DHA on TPA- or EGF-induced AP-1 transactivation and cell transformation in a dose-dependent manner. The results of this study demonstrate that the inhibitory effects of ω3 fatty acids on tumorigenesis are more significant for DHA than for EPA and are related to an inhibition of AP-1. Similarly, because AA abrogates the beneficial effects of DHA, the dietary ratio of ω6 to ω3 fatty acids may be a significant factor in mediating tumor development. PMID:11416221

  16. Identification and characterization of Ref-1, a nuclear protein that facilitates AP-1 DNA-binding activity.

    PubMed Central

    Xanthoudakis, S; Curran, T

    1992-01-01

    Fos and Jun form a heterodimeric complex that regulates gene transcription by binding to the activator protein-1 (AP-1) DNA sequence motif. Previously, we demonstrated that the DNA-binding activity of Fos and Jun is regulated in vitro by a novel redox (reduction-oxidation) mechanism. Reduction of a conserved cysteine (cys) residue in the DNA-binding domains of Fos and Jun by chemical reducing agents or by a nuclear redox factor stimulates DNA-binding activity. Here, we describe purification and characterization of a 37 kDa protein (Ref-1) corresponding to the redox factor. Although Ref-1 does not bind to the AP-1 site in association with Fos and Jun, it partially copurifies with a subset of AP-1 proteins. Purified Ref-1 protein stimulates AP-1 DNA-binding activity through the conserved Cys residues in Fos and Jun, but it does not alter the DNA-binding specificity of Fos and Jun. Ref-1 may represent a novel redox component of the signal transduction processes that regulate eukaryotic gene expression. Images PMID:1537340

  17. TNF¿ and GM-CSF-induced activation of the CAEV promoter is independent of AP-1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Caprine arthritis encephalitis virus transcription is under the control of the viral promoter within the long terminal repeat. Previous studies with the closely related maedi visna lentivirus have indicated that viral transcription is dependent upon the AP-1 transcription factor. Other studies hav...

  18. 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.

  19. 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

    PubMed Central

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

    2014-01-01

    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. PMID:24658403

  20. 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

  1. Transcriptional activation of the fra-1 gene by AP-1 is mediated by regulatory sequences in the first intron.

    PubMed Central

    Bergers, G; Graninger, P; Braselmann, S; Wrighton, C; Busslinger, M

    1995-01-01

    Constitutive expression of c-Fos, FosB, Fra-1, or c-Jun in rat fibroblasts leads to up-regulation of the immediate-early gene fra-1. Using the posttranslational FosER induction system, we demonstrate that this AP-1-dependent stimulation of fra-1 expression is rapid, depends on a functional DNA-binding domain of FosER, and is a general phenomenon observed in different cell types. In vitro mutagenesis and functional analysis of the rat fra-1 gene in stably transfected Rat-1A-FosER fibroblasts indicated that basal and AP-1-regulated expression of the fra-1 gene depends on regulatory sequences in the first intron which comprise a consensus AP-1 site and two AP-1-like elements. We have also investigated the transactivating and transforming properties of the Fra-1 protein to address the significance of fra-1 up-regulation. The entire Fra-1 protein fused to the DNA-binding domain of Ga14 is shown to lack any transactivation function, and yet it possesses oncogenic potential, as overexpression of Fra-1 in established rat fibroblasts results in anchorage-independent growth in vitro and tumor development in athymic mice, fra-1 is therefore not only induced by members of the Fos family, but its gene product may also contribute to cellular transformation by these proteins. Together, these data identify fra-1 as a unique member of the fos gene family which is under positive control by AP-1 activity. PMID:7791782

  2. S100P/RAGE signaling regulates microRNA-155 expression via AP-1 activation in colon cancer

    PubMed Central

    Onyeagucha, Benjamin Chidi; Mercado-Pimentel, Melania E.; Hutchison, Jennifer; Flemington, Erik K.; Nelson, Mark A.

    2013-01-01

    Accumulating evidence indicates that elevated S100P promotes the pathogenesis of cancers, including colon cancer. S100P exerts its effects by binding to and activating the Receptor for Advance Glycation End-products (RAGE). The effects of up-regulated S100P/RAGE signaling on cell functions are well documented. Despite these observations, little is known about the downstream targets of S100P/RAGE signaling. In the present study, we demonstrated for the first time that activation of RAGE by S100P regulates oncogenic microRNA-155 (miR-155) expression through Activator Protein-1 (AP-1) stimulation in colon cancer cells. Ectopic S100P up-regulated miR-155 levels in human colon cancer cells. Conversely, knockdown of S100P resulted in a decrease in miR-155 levels. Exogenous S100P induced miR-155 expression, but blockage of the RAGE with anti-RAGE antibody suppressed the induction of miR-155 by exogenous S100P. Attenuation of AP-1 activation through pharmacological inhibition of MEK activation or genetic inhibition of c-Jun activation using dominant negative c-Jun (TAM67) suppressed miR-155 induction by exogenous S100P. Also, S100P treatment stimulated the enrichment of c-Fos, an AP-1 family member, at the miR-155 host gene promoter site. Finally, a functional study demonstrated that miR-155 knockdown decreases colon cancer cell growth, motility, and invasion. Altogether, these data demonstrate that the expression of miR-155 is regulated by S100P and is dependent on RAGE activation and stimulation of AP-1. PMID:23693020

  3. 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

  4. Trans-repressor activity of nuclear glycosaminoglycans on Fos and Jun/AP-1 oncoprotein-mediated transcription.

    PubMed

    Busch, S J; Martin, G A; Barnhart, R L; Mano, M; Cardin, A D; Jackson, R L

    1992-01-01

    Heparin blocks the phorbol ester-induced progression of nontransformed cells through the G0/G1 phase (Wright, T.C., L.A. Pukac, J.J. Castellot, M.J. Karnovsky, R.A. Levine, H.-Y. Kim-Park, and J. Campisi. 1989. Proc. Natl. Acad. Sci. USA. 86: 3199-3203) or G1 to S phase (Reilly, C. F., M. S. Kindy, K. E. Brown, R. D. Rosenberg, and G. E Sonenshein. 1989. J. Biol. Chem. 264:6990-6995) of the cell cycle. Cell cycle arrest was associated with decreased levels of stage-specific mRNAs suggesting transcriptional regulation of cell growth. In the present report, we show that heparin selectively repressed TPA-inducible AP-1-mediated gene expression. Heparin-induced trans-repression was observed in primary vascular smooth muscle cells, as well as in the transformed HeLa cell line and in nondifferentiated F9 teratocarcinoma cells. Inhibition of AP-1-mediated trans-activation occurred with heparin and pentosan polysulfate but not with chondroitin sulfate A or C. Heparin-binding peptides or heparitinase I addition to nuclear lysates of heparin-treated cells allowed enhanced recovery of endogenous AP-1-specific DNA binding activity. We propose a model in which nuclear glycosaminoglycans play a trans-regulatory role in altering the patterns of inducible gene expression. PMID:1730747

  5. Cdk3-promoted epithelial-mesenchymal transition through activating AP-1 is involved in colorectal cancer metastasis

    PubMed Central

    Tang, Na; Li, Yuejin; Peng, Zhengke; Lu, Chengrong; Dong, Zigang; Tang, Faqing

    2016-01-01

    Cyclin dependent kinase-3 (Cdk3) is a positive regulator of the G1 mammalian cell cycle phase. Cdk3 is involved in cancer progression, but very little is known about its mechanism in cancer development and progression. Herein, we found that Cdk3 increased colorectal cancer metastasis through promoting epithelial-mesenchymal transition (EMT) shift. Cdk3 was found to highly express in metastatic cancer and induce cell motility and invasion. Cdk3 was shown to phosphorylate c-Jun at Ser 63 and Ser 73 in vitro and ex vivo. Cdk3-phosphorylated c-Jun at Ser 63 and Ser 73 resulted in an increased AP-1 activity. Ectopic expression of Cdk3 promoted colorectal cancer from epithelial to mesenchymal transition conjugating AP-1 activation, while AP-1 inhibition dramatically decreased Cdk3-increased EMT shift. These results showed that the Cdk3/c-Jun signaling axis mediating epithelial-mesenchymal transition plays an important role in colorectal cancer metastasis. PMID:26755651

  6. 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. PMID:26585143

  7. Control of Sty1 MAPK activity through stabilisation of the Pyp2 MAPK phosphatase.

    PubMed

    Kowalczyk, Katarzyna M; Hartmuth, Sonya; Perera, David; Stansfield, Peter; Petersen, Janni

    2013-08-01

    In all eukaryotes tight control of mitogen-activated protein kinase (MAPK) activity plays an important role in modulating intracellular signalling in response to changing environments. The fission yeast MAPK Sty1 (also known as Spc1 or Phh1) is highly activated in response to a variety of external stresses. To avoid segregation of damaged organelles or chromosomes, strong Sty1 activation transiently blocks mitosis and cell division until such stresses have been dealt with. MAPK phosphatases dephosphorylate Sty1 to reduce kinase activity. Therefore, tight control of MAPK phosphatases is central for stress adaptation and for cell division to resume. In contrast to Pyp1, the fission yeast Pyp2 MAPK phosphatase is under environmental control. Pyp2 has a unique sequence (the linker region) between the catalytic domain and the N-terminal MAPK-binding site. Here we show that the Pyp2 linker region is a destabilisation domain. Furthermore, the linker region is highly phosphorylated to increase Pyp2 protein stability and this phosphorylation is Sty1 dependent. Our data suggests that Sty1 activation promotes Pyp2 phosphorylation to increase the stability of the phosphatase. This MAPK-dependent Pyp2 stabilisation allows cells to attenuate MAPK signalling and resume cell division, once stresses have been dealt with. PMID:23690545

  8. Activation of NF-κB and AP-1 Mediates Hyperproliferation by Inducing β-Catenin and c-Myc in Helicobacter pylori-Infected Gastric Epithelial Cells

    PubMed Central

    Byun, Eunyoung; Park, Bohye; Lim, Joo Weon

    2016-01-01

    Purpose In the gastric mucosa of Helicobacter pylori (H. pylori)-infected patients with gastritis or adenocarcinoma, proliferation of gastric epithelial cells is increased. Hyperproliferation is related to induction of oncogenes, such as β-catenin and c-myc. Even though transcription factors NF-κB and AP-1 are activated in H. pylori-infected cells, whether NF-κB or AP-1 regulates the expression of β-catenein or c-myc in H. pylori-infected cells has not been clarified. The present study was undertaken to investigate whether H. pylori-induced activation of NF-κB and AP-1 mediates the expression of oncogenes and hyperproliferation of gastric epithelial cells. Materials and Methods Gastric epithelial AGS cells were transiently transfected with mutant genes for IκBα (MAD3) and c-Jun (TAM67) or treated with a specific NF-κB inhibitor caffeic acid phenethyl ester (CAPE) or a selective AP-1 inhibitor SR-11302 to suppress activation of NF-κB or AP-1, respecively. As reference cells, the control vector pcDNA was transfected to the cells. Wild-type cells or transfected cells were cultured with or without H. pylori. Results H. pylori induced activation of NF-κB and AP-1, cell proliferation, and expression of oncogenes (β-catenein, c-myc) in AGS cells, which was inhibited by transfection of MAD3 and TAM67. Wild-type cells and the cells transfected with pcDNA showed similar activities of NF-κB and AP-1, proliferation, and oncogene expression regardless of treatment with H. pylori. Both CAPE and SR-11302 inhibited cell proliferation and expression of oncogenes in H. pylori-infected cells. Conclusion H. pylori-induced activation of NF-κB and AP-1 regulates transcription of oncogenes and mediates hyperproliferation in gastric epithelial cells. PMID:26996564

  9. A cluster region of AP-1 responsive elements is required for transcriptional activity of mouse ODC gene by hepatocyte growth factor.

    PubMed

    Bianchi, Laura; Tacchini, Lorenza; Matteucci, Emanuela; Desiderio, Maria Alfonsina

    2002-05-01

    Ornithine decarboxylase (ODC) activity is regulated by a variety of mechanisms including transcription, translation, and RNA and protein half-life. Since in mouse B16-F1 melanoma cells an early and remarkable (about 6-fold) increase in steady state mRNA levels was observed after hepatocyte growth factor (HGF) treatment, we investigated the transcriptional regulation of mouse ODC promoter. Transient transfection of various ODC-luciferase promoter constructs into the B16-Fl cells in combination with electrophoretic mobility shift assays identified the HGF-responsive element as a cluster of three AP-1 binding sites (-1660 to -1572). Even if each site differs from the canonical TPA responsive element for one nucleotide, only the first two AP-1 consensus sequences seemed to be functional since allowed DNA-binding activity of nuclear proteins after HGF treatment. Comparison of the results of transfection assays with the pOD2.5-luc (2.5 kb gene fragment) and with the construct deprived of the AP-1 cluster pOD-B-luc showed that this 50 bp region was required for ODC transactivating activity in response to HGF. Since in B16-F1 cells HGF increased AP-1 activity and the mRNA expression of various AP-1 subunits, we may conclude that HGF-induced transcription of mouse ODC was largely due to triggering of AP-1 pathway. PMID:12054494

  10. Activin A enhances MMP-7 activity via the transcription factor AP-1 in an esophageal squamous cell carcinoma cell line.

    PubMed

    Yoshinaga, Keiji; Mimori, Koshi; Inoue, Hiroshi; Kamohara, Yukio; Yamashita, Keishi; Tanaka, Fumiaki; Mori, Masaki

    2008-09-01

    Activin A, a member of the transforming growth factor beta (TGF-beta) superfamily, is often overexpressed in solid carcinomas. We have previously reported that the expression of activin A is associated with lymph node metastasis in esophageal cancer. In the current study, our goal was to clarify the molecular mechanisms underlying the aggressive behavior of tumors expressing high levels of activin A. Using cDNA microarrays, the gene expression profile of a human esophageal carcinoma cell line (KYSE170) stably transfected with activin betaA (Act-betaA, a subunit of activin A) was compared with those of control human esophageal carcinoma cell lines. We found that expression of MMP-7 was higher in the Act-betaA transfectants than in the control cells. To reveal the mechanism of expression of MMP-7 mediated by activin A, we evaluated mRNA expression of MMP-7 and Act-betaA with or without activin A neutralizing antibody, using real-time PCR and Northern blot analysis. We also performed promoter analysis of the MMP-7 promoter and assessed c-Jun and Smad2/3 expression. MMP-7 expression in the transfectants was correlated with the level of Act-betaA expression and was reduced by activin A neutralizing antibody. The Act-betaA transfectants had higher MMP-7 promoter activity than control cells. MMP-7 promoter activity was not affected by mutation in the Smad binding site, while mutation of the AP-1 binding site did reduce activity. Moreover, the expression of c-Jun was increased in Act-betaA transfectants. These results indicate that activin A may modulate the expression of MMP-7 via AP-1 and not through Smad2/3. PMID:18695873

  11. 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 Central

    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. PMID:21814482

  12. 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

  13. MEKK1 regulates the AP-1 dimer repertoire via control of JunB transcription and Fra-2 protein stability.

    PubMed

    Cuevas, Bruce D; Uhlik, Mark T; Garrington, Timothy P; Johnson, Gary L

    2005-01-27

    Activator protein 1 (AP-1) transcription factor dimers are composed of Jun, Fos, and ATF member proteins, but the mechanisms that determine AP-1 composition are not clearly defined and the function of specific dimers is not well understood. MEKK1 is a mitogen-activated protein kinase (MAPK) kinase kinase and an ubiquitin ligase that regulates both the extracellular signal-regulated kinase 1/2 and the c-Jun amino-terminal kinase. Herein, we demonstrate that MEKK1 regulates the AP-1 protein repertoire. Both FGF-2 and phorbol ester-inducible urokinase-type plasminogen activator (uPA) expression requires AP-1 binding to an enhancer element in the uPA promoter, and we have previously shown that FGF-2 or PMA induction of uPA expression is strongly dependent on MEKK1. JunB mRNA is significantly increased in MEKK1-/- cells, demonstrating that MEKK1 suppresses JunB mRNA expression. Upregulation of JunB expression in MEKK1-/- cells forms an inhibitory AP-1 complex that binds to the uPA promoter and inhibits uPA transcription. MEKK1 also regulates Fra-2 protein stability by inducing Fra-2 ubiquitination and degradation. MEKK1 regulates AP-1-dependent gene expression by regulating the expression, activity and degradation of component members of the AP-1 complex. Controlling the repertoire of a transcription factor complex is a newly defined function for an MAPK kinase kinase. PMID:15558021

  14. Insulin-stimulated expression of c-fos, fra1 and c-jun accompanies the activation of the activator protein-1 (AP-1) transcriptional complex.

    PubMed Central

    Griffiths, M R; Black, E J; Culbert, A A; Dickens, M; Shaw, P E; Gillespie, D A; Tavaré, J M

    1998-01-01

    The activator protein-1 (AP-1) transcriptional complex is made up of members of the Fos (c-Fos, FosB, Fra1, Fra2) and Jun (c-Jun, JunB, JunD) families and is stimulated by insulin in several cell types. The mechanism by which insulin activates this complex is not well understood but it is dependent on the activation of the Erk1 and Erk2 isoforms of mitogen-activated protein kinases. In the current study we show that the AP-1 complex isolated from insulin-stimulated cells contained c-Fos, Fra1, c-Jun and JunB. The activation of the AP-1 complex by insulin was accompanied by (i) a transient increase in c-fos expression, and the transactivation of the ternary complex factors Elk1 and Sap1a, in an Erk1/Erk2-dependent fashion; (ii) a substantial increase in the expression of Fra1 protein and mRNA, which was preceded by a transient decrease in its electrophoretic mobility upon SDS/PAGE, indicative of phosphorylation; and (iii) a sustained increase in c-jun expression without increasing c-Jun phosphorylation on serines 63 and 73 or activation of the stress-activated kinase JNK/SAPK. In conclusion, insulin appears to stimulate the activity of the AP-1 complex primarily through a change in the abundance of the components of this complex, although there may be an additional role for Fra1 phosphorylation. PMID:9742208

  15. Activation of TGF-β1 promoter by hepatitis C virus-induced AP-1 and Sp1: role of TGF-β1 in hepatic stellate cell activation and invasion.

    PubMed

    Presser, Lance D; McRae, Steven; Waris, Gulam

    2013-01-01

    Our previous studies have shown the induction and maturation of transforming growth factor-beta 1 (TGF-β1) in HCV-infected human hepatoma cells. In this study, we have investigated the molecular mechanism of TGF-β1 gene expression in response to HCV infection. We demonstrate that HCV-induced transcription factors AP-1, Sp1, NF-κB and STAT-3 are involved in TGF-β1 gene expression. Using chromatin immunoprecipitation (ChIP) assay, we further show that AP-1 and Sp1 interact with TGF-b1 promoter in vivo in HCV-infected cells. In addition, we demonstrate that HCV-induced TGF-β1 gene expression is mediated by the activation of cellular kinases such as p38 MAPK, Src, JNK, and MEK1/2. Next, we determined the role of secreted bioactive TGF-β1 in human hepatic stellate cells (HSCs) activation and invasion. Using siRNA approach, we show that HCV-induced bioactive TGF-β1 is critical for the induction of alpha smooth muscle actin (α-SMA) and type 1 collagen, the markers of HSCs activation and proliferation. We further demonstrate the potential role of HCV-induced bioactive TGF-β1 in HSCs invasion/cell migration using a transwell Boyden chamber. Our results also suggest the role of HCV-induced TGF-β1 in HCV replication and release. Collectively, these observations provide insight into the mechanism of TGF-β1 promoter activation, as well as HSCs activation and invasion, which likely manifests in liver fibrosis associated with HCV infection. PMID:23437118

  16. p38MAPK activation and DUSP10 expression in meningiomas.

    PubMed

    Johnson, Mahlon D; Reeder, Jay E; O'Connell, Mary

    2016-08-01

    The mitogen activated protein kinase (MAPK) p38MAPK has been implicated in regulation of cell proliferation and apoptosis. However, expression, activation and regulation has not been studied in meningiomas, to our knowledge. p38MAPK is regulated, in part, by dual specificity phosphatases (DUSP) that inactivate signaling by dephosphorylation. DUSP10 is also a likely participant in regulating meningioma proliferation. Five fetal and an adult human leptomeninges and 37 meningioma cultures (MC) were evaluated for DUSP10 as well as phosphorylation of its substrates p38MAPK and p44/42MAPK by western blot and DUSP10 expression by polymerase chain reaction. Platelet derived growth factor-BB (PDGF-BB), transforming growth factor B1 (TGFB1) and cerebrospinal fluid effects on DUSP10 and signaling were also studied in vitro. DUSP10 and phospho-p38MAPK and phospho-p44/42MAPK were detected in all six leptomeninges. DUSP10 was detected in 13 of 17 World Health Organization grade I, 11 of 14 grade II and four of six grade III meningiomas. Phospho-p38MAPK was detected in nine of 17 grade I, two of six grade II, and four of six grade III meningiomas. In the majority of meningiomas DUSP10 expression correlated inversely with phosphorylation of p38MAPK. PDGF-BB increased DUSP10 in MC2 and MC4 and weakly in MC3. TGFB1 increased phosphorylation of p38MAPK and caspase 3 activation. Thus p38MAPK and DUSP10 likely participate in the pathogenesis of meningiomas. PMID:27050915

  17. MAPK-Activated Protein Kinases (MKs): Novel Insights and Challenges

    PubMed Central

    Gaestel, Matthias

    2016-01-01

    Downstream of MAPKs, such as classical/atypical ERKs and p38 MAPKs, but not of JNKs, signaling is often mediated by protein kinases which are phosphorylated and activated by MAPKs and, therefore, designated MAPK-activated protein kinases (MAPKAPKs). Recently, novel insights into the specificity of the assembly of MAPK/MAPKAPK hetero-dimeric protein kinase signaling complexes have been gained. In addition, new functional aspects of MKs have been described and established functions have been challenged. This short review will summarize recent developments including the linear motif (LM) in MKs, the ERK-independent activation of RSK, the RSK-independent effects of some RSK-inhibitors and the challenged role of MK5/PRAK in tumor suppression. PMID:26779481

  18. MAPK-Activated Protein Kinases (MKs): Novel Insights and Challenges.

    PubMed

    Gaestel, Matthias

    2015-01-01

    Downstream of MAPKs, such as classical/atypical ERKs and p38 MAPKs, but not of JNKs, signaling is often mediated by protein kinases which are phosphorylated and activated by MAPKs and, therefore, designated MAPK-activated protein kinases (MAPKAPKs). Recently, novel insights into the specificity of the assembly of MAPK/MAPKAPK hetero-dimeric protein kinase signaling complexes have been gained. In addition, new functional aspects of MKs have been described and established functions have been challenged. This short review will summarize recent developments including the linear motif (LM) in MKs, the ERK-independent activation of RSK, the RSK-independent effects of some RSK-inhibitors and the challenged role of MK5/PRAK in tumor suppression. PMID:26779481

  19. Mitogen-activated protein kinase (MAPK) in cardiac tissues.

    PubMed

    Page, C; Doubell, A F

    Mitogen-activated protein kinase (MAPK) has recently emerged as a prominent role player in intracellular signalling in the ventricular myocyte with attention being focussed on its possible role in the development of ventricular hypertrophy. It is becoming clear that MAPK is also active in other cells of cardiac origin such as cardiac fibroblasts and possible functions of this signalling pathway in the heart have yet to be explored. In this report the mammalian MAPK pathway is briefly outlined, before reviewing current knowledge of the MAPK pathway in cardiac tissue (ventricular myocytes, vascular smooth muscle cells and cardiac fibroblasts). New data is also presented on the presence and activity of MAPK in two additional cardiac celltypes namely atrial myocytes and vascular endothelial cells from the coronary microcirculation. PMID:8739228

  20. 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

  1. Anti-Inflammatory Effects of α-Galactosylceramide Analogs in Activated Microglia: Involvement of the p38 MAPK Signaling Pathway

    PubMed Central

    Chung, Young Sun; Park, Seung Bum; Kim, Hee-Sun

    2014-01-01

    Microglial activation plays a pivotal role in the development and progression of neurodegenerative diseases. Thus, anti-inflammatory agents that control microglial activation can serve as potential therapeutic agents for neurodegenerative diseases. Here, we designed and synthesized α-galactosylceramide (α-GalCer) analogs to exert anti-inflammatory effects in activated microglia. We performed biological evaluations of 25 α-GalCer analogs and observed an interesting preliminary structure-activity relationship in their inhibitory influence on NO release and TNF-α production in LPS-stimulated BV2 microglial cells. After identification of 4d and 4e as hit compounds, we further investigated the underlying mechanism of their anti-inflammatory effects using RT-PCR analysis. We confirmed that 4d and 4e regulate the expression of iNOS, COX-2, IL-1β, and IL-6 at the mRNA level and the expression of TNF-α at the post-transcriptional level. In addition, both 4d and 4e inhibited LPS-induced DNA binding activities of NF-κB and AP-1 and phosphorylation of p38 MAPK without affecting other MAP kinases. When we examined the anti-inflammatory effect of a p38 MAPK-specific inhibitor, SB203580, on microglial activation, we observed an identical inhibitory pattern as that of 4d and 4e, not only on NO and TNF-α production but also on the DNA binding activities of NF-κB and AP-1. Taken together, these results suggest that p38 MAPK plays an important role in the anti-inflammatory effects of 4d and 4e via the modulation of NF-κB and AP-1 activities. PMID:24523867

  2. Multiple Protein Kinases via Activation of Transcription Factors NF-κB, AP-1 and C/EBP-δ Regulate the IL-6/IL-8 Production by HIV-1 Vpr in Astrocytes

    PubMed Central

    Gangwani, Mohitkumar R.; Kumar, Anil

    2015-01-01

    Neurocognitive impairments affect a substantial population of HIV-1 infected individuals despite the success of anti-retroviral therapy in controlling viral replication. Astrocytes are emerging as a crucial cell type that might be playing a very important role in the persistence of neuroinflammation seen in patients suffering from HIV-1 associated neurocognitive disorders. HIV-1 viral proteins including Vpr exert neurotoxicity through direct and indirect mechanisms. Induction of IL-8 in microglial cells has been shown as one of the indirect mechanism through which Vpr reduces neuronal survival. We show that HIV-1 Vpr induces IL-6 and IL-8 in astrocytes in a time-dependent manner. Additional experiments utilizing chemical inhibitors and siRNA revealed that HIV-1 Vpr activates transcription factors NF-κB, AP-1 and C/EBP-δ via upstream protein kinases PI3K/Akt, p38-MAPK and Jnk-MAPK leading to the induction of IL-6 and IL-8 in astrocytes. We demonstrate that one of the mechanism for neuroinflammation seen in HIV-1 infected individuals involves induction of IL-6 and IL-8 by Vpr in astrocytes. Understanding the molecular pathways involved in the HIV-1 neuroinflammation would be helpful in the design of adjunct therapy to ameliorate some of the symptoms associated with HIV-1 neuropathogenesis. PMID:26270987

  3. G13-dependent activation of MAPK by thyrotropin.

    PubMed

    Büch, Thomas R H; Biebermann, Heike; Kalwa, Hermann; Pinkenburg, Olaf; Hager, Denise; Barth, Holger; Aktories, Klaus; Breit, Andreas; Gudermann, Thomas

    2008-07-18

    Stimulation of the thyrotropin receptor (TSHR) activates G proteins of all four subfamilies (G(s), G(i/o), G(q/11), and G(12/13)). Whereas G(s)/cAMP-dependent cellular responses upon TSHR stimulation are well established, other signaling pathways are less characterized. We evaluated TSH-elicited cellular responses in human follicular thyroid carcinoma cells stably expressing the TSHR and in primary, nonneoplastic human thyrocytes. In these cellular models, stimulation with TSH caused activation of p44/42 MAPK and subsequent induction of c-Fos. MAPK stimulation occurred independently of G(s), G(i/o), and G(q/11) signaling. Dominant negative constructs of G(12) or G(13) as well as shRNA-mediated suppression of Galpha(12) or Galpha(13) revealed that MAPK activation was dependent on G(13) but not on G(12) signaling. Furthermore, G(13)-dependent transactivation of the epidermal growth factor receptor was necessary for MAPK activation in follicular carcinoma cells, whereas EGFR was not involved in MAPK activation in nonneoplastic primary thyrocytes. The use of bacterial inhibitors of monomeric GTPases revealed that MAPK activation proceeded independently of Rho proteins but was clostridial toxin B-sensitive, suggesting involvement of Cdc42 or Rac. Thus, our data shed new light on cAMP-independent TSHR signaling and identify the first G(13)-dependent TSHR signaling pathway in human thyrocytes. PMID:18445595

  4. 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. PMID:23770440

  5. The nuclear factor YY1 suppresses the human gamma interferon promoter through two mechanisms: inhibition of AP1 binding and activation of a silencer element.

    PubMed Central

    Ye, J; Cippitelli, M; Dorman, L; Ortaldo, J R; Young, H A

    1996-01-01

    Our group has previously reported that the nuclear factor Yin-Yang 1 (YY1), a ubiquitous DNA-binding protein, is able to interact with a silencer element (BE) in the gamma interferon (IFN-gamma) promoter region. In this study, we demonstrated that YY1 can directly inhibit the activity of the IFN-gamma promoter by interacting with multiple sites in the promoter. In cotransfection assays, a YY1 expression vector significantly inhibited IFN-gamma promoter activity. Mutation of the YY1 binding site in the native IFN-gamma promoter was associated with an increase in the IFN-gamma promoter activity. Analysis of the DNA sequences of the IFN-gamma promoter revealed a second functional YY1 binding site (BED) that overlaps with an AP1 binding site. In this element, AP1 enhancer activity was suppressed by YY1. Since the nuclear level of YY1 does not change upon cell activation, our data support a model that the nuclear factor YY1 acts to suppress basal IFN-gamma transcription by interacting with the promoter at multiple DNA binding sites. This repression can occur through two mechanisms: (i) cooperation with an as-yet-unidentified AP2-like repressor protein and (ii) competition for DNA binding with the transactivating factor AP1. PMID:8756632

  6. Alpha-melanocyte-stimulating hormone modulates activation of NF-kappa B and AP-1 and secretion of interleukin-8 in human dermal fibroblasts.

    PubMed

    Böhm, M; Schulte, U; Kalden, H; Luger, T A

    1999-10-20

    Alpha-melanocyte-stimulating hormone (alpha-MSH) has evolved as a mediator of diverse biological activities in an ever-growing number of non-melanocytic cell types. One mechanism by which alpha-MSH exerts its effects is modulation of AP-1 and NF-kappa B. These two transcription factors also play an important role in fibroblasts, in extracellular matrix composition, and in cytokine expression. By use of electric mobility shift assays, we demonstrate that alpha-MSH (10(-6) to 10(-14) M) activates AP-1 in human dermal fibroblasts, whereas coincubation with interleukin-1 beta (IL-1 beta) results in suppression of its activation. alpha-MSH also induces activation of NF-kappa B but does not modulate DNA binding on costimulation with IL-1 beta. Since AP-1 and NF-kappa B are key elements in controlling interleukin-8 (IL-8) transcription, human fibroblasts were treated with alpha-MSH and IL-1 beta for 24 hours, and cytokine levels in the supernatants were measured by ELISA. alpha-MSH alone had little effect, whereas coincubation with IL-1 beta led to marked downregulation of IL-8 secretion (at most 288 +/- 152 ng/mL) when compared to treatment with IL-1 beta alone (919 +/- 157 ng/mL). Our results indicate that alpha-MSH exerts modulatory effects on the activation of NF-kappa B and AP-1, and that it can regulate chemokine secretion in human dermal fibroblasts. These effects of alpha-MSH may have important regulatory functions in extracellular matrix composition, wound healing, or angiogenesis. PMID:10816661

  7. Cytoskeletal reorganization and TPA differently modify AP-1 to induce the urokinase-type plasminogen activator gene in LLC-PK1 cells.

    PubMed Central

    Lee, J S; von der Ahe, D; Kiefer, B; Nagamine, Y

    1993-01-01

    Urokinase-type plasminogen activator (uPA) is an extracellular protease and expressed in various cells that exhibit dynamic changes in cell morphology, suggesting a link between cytoskeletal reorganization (CSR) and uPA expression. CSR can be induced by pharmacological agents, such as by colchicine for microtubule cytoskeleton and by cytochalasin for microfilament cytoskeleton. Using these agents, we previously showed that CSR induced the uPA gene in LLC-PK1 cells independently of the protein kinase C and cAMP-dependent protein kinase. Here we show that the induction of the uPA gene by CSR is mediated by the activation of c-Jun which interacts with an AP-1-like site located 2 kb upstream of the uPA gene. 12-O-tetradecanoylphorbol 13-acetate (TPA) induces the uPA gene through the same elements, but additionally utilizes an adjacent PEA3 element and induces c-fos. Furthermore, CSR induces a greater accumulation and a more pronounced phosphorylation of c-Jun than TPA induction. AP-1 is a positive regulator of growth and oncogenesis, and CSR is an integral part of these processes. Our results provide a view how CSR and AP-1 could be coupled in these processes. We also show that TPA and CSR act synergistically, suggesting a model where an initial activation signal could be amplified by CSR. Images PMID:8346015

  8. Coenzyme Q0 regulates NFκB/AP-1 activation and enhances Nrf2 stabilization in attenuation of LPS-induced inflammation and redox imbalance: Evidence from in vitro and in vivo studies.

    PubMed

    Yang, Hsin-Ling; Lin, Ming-Wei; Korivi, Mallikarjuna; Wu, Jia-Jiuan; Liao, Chun-Huei; Chang, Chia-Ting; Liao, Jiunn-Wang; Hseu, You-Cheng

    2016-02-01

    Coenzyme Q (CoQ) analogs with variable number of isoprenoid units have been demonstrated as anti-inflammatory and antioxidant/pro-oxidant molecules. In this study we used CoQ0 (2,3-dimethoxy-5-methyl-1,4-benzoquinone, zero isoprenoid side-chains), a novel quinone derivative, and investigated its molecular actions against LPS-induced inflammation and redox imbalance in murine RAW264.7 macrophages and mice. In LPS-stimulated macrophages, non-cytotoxic concentrations of CoQ0 (2.5-10 μM) inhibited iNOS/COX-2 protein expressions with subsequent reductions of NO, PGE2, TNF-α and IL-1β secretions. This inhibition was reasoned by suppression of NFκB (p65) activation, and inhibition of AP-1 (c-Jun., c-Fos, ATF2) translocation. Our findings indicated that IKKα-mediated I-κB degradation and MAPK-signaling are involved in regulation of NFκB/AP-1 activation. Furthermore, CoQ0 triggered HO-1 and NQO-1 genes through increased Nrf2 nuclear translocation and Nrf2/ARE-signaling. This phenomenon was confirmed by diminished CoQ0 protective effects in Nrf2 knockdown cells, where LPS-induced NO, PGE2, TNF-α and IL-1β productions remained high. Molecular evidence revealed that CoQ0 enhanced Nrf2 steady-state level at both transcriptional and translational levels. CoQ0-induced Nrf2 activation appears to be regulated by ROS-JNK-signaling cascades, as evidenced by suppressed Nrf2 activation upon treatment with pharmacological inhibitors of ROS (N-acetylcysteine) and JNK (SP600125). Besides, oral administration of CoQ0 (5 mg/kg) suppressed LPS-induced (1 mg/kg) induction of iNOS/COX-2 and TNF-α/IL-1β through tight regulation of NFκB/Nrf2 signaling in mice liver and spleen. Our findings conclude that pharmacological actions of CoQ0 are mediated via inhibition of NFκB/AP-1 activation and induction of Nrf2/ARE-signaling. Owing to its potent anti-inflammatory and antioxidant properties, CoQ0 could be a promising candidate to treat inflammatory disorders. PMID:26548719

  9. RAF inhibitors that evade paradoxical MAPK pathway activation.

    PubMed

    Zhang, Chao; Spevak, Wayne; Zhang, Ying; Burton, Elizabeth A; Ma, Yan; Habets, Gaston; Zhang, Jiazhong; Lin, Jack; Ewing, Todd; Matusow, Bernice; Tsang, Garson; Marimuthu, Adhirai; Cho, Hanna; Wu, Guoxian; Wang, Weiru; Fong, Daniel; Nguyen, Hoa; Shi, Songyuan; Womack, Patrick; Nespi, Marika; Shellooe, Rafe; Carias, Heidi; Powell, Ben; Light, Emily; Sanftner, Laura; Walters, Jason; Tsai, James; West, Brian L; Visor, Gary; Rezaei, Hamid; Lin, Paul S; Nolop, Keith; Ibrahim, Prabha N; Hirth, Peter; Bollag, Gideon

    2015-10-22

    Oncogenic activation of BRAF fuels cancer growth by constitutively promoting RAS-independent mitogen-activated protein kinase (MAPK) pathway signalling. Accordingly, RAF inhibitors have brought substantially improved personalized treatment of metastatic melanoma. However, these targeted agents have also revealed an unexpected consequence: stimulated growth of certain cancers. Structurally diverse ATP-competitive RAF inhibitors can either inhibit or paradoxically activate the MAPK pathway, depending whether activation is by BRAF mutation or by an upstream event, such as RAS mutation or receptor tyrosine kinase activation. Here we have identified next-generation RAF inhibitors (dubbed 'paradox breakers') that suppress mutant BRAF cells without activating the MAPK pathway in cells bearing upstream activation. In cells that express the same HRAS mutation prevalent in squamous tumours from patients treated with RAF inhibitors, the first-generation RAF inhibitor vemurafenib stimulated in vitro and in vivo growth and induced expression of MAPK pathway response genes; by contrast the paradox breakers PLX7904 and PLX8394 had no effect. Paradox breakers also overcame several known mechanisms of resistance to first-generation RAF inhibitors. Dissociating MAPK pathway inhibition from paradoxical activation might yield both improved safety and more durable efficacy than first-generation RAF inhibitors, a concept currently undergoing human clinical evaluation with PLX8394. PMID:26466569

  10. 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. PMID:26941330

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

    PubMed Central

    Parmar, Hirendrasinh B.; Duncan, Roy

    2016-01-01

    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. PMID:26941330

  12. Activation of AP-1 and nuclear factor-kappaB transcription factors is involved in hydrogen peroxide-induced apoptotic cell death of oligodendrocytes.

    PubMed

    Vollgraf, U; Wegner, M; Richter-Landsberg, C

    1999-12-01

    H2O2-induced onset and execution of programmed cell death in mature rat brain oligodendrocytes in culture is accompanied by the induction and nuclear translocation of the transcription factors AP-1 and nuclear factor-kappaB (NF-kappaB), both of which have been discussed as regulators of cell death and survival. Supershift analysis of nuclear extracts indicated that the AP-1 complex consists of c-Jun, c-Fos, JunD, and possibly JunB proteins, and that the NF-kappaB complex contains p50, p65, and c-Rel proteins. The first signs of DNA fragmentation were seen already during the first hour after the treatment. DNA fragmentation could be prevented by the antioxidants pyrrolidine dithiocarbamate and vitamin E, by the nuclease inhibitor aurintricarboxylic acid, and by preincubation with the iron chelator deferoxamine (DFO). Additionally, DFO protected oligodendrocytes from H2O2-induced cytotoxic effects as assessed by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, and suppressed the formation of free radicals. DFO alone led to a slight increase and in combination with H2O2 synergistically induced DNA-binding activities of AP-1 and NF-kappaB in oligodendrocytes. Our data suggest that although low levels of H2O2 directly activate AP-1 and NF-kappaB and might contribute to signal transduction pathways promoting cell survival, the formation and action of hydroxyl radicals promote cell death mechanisms that can be attenuated by the iron chelator DFO. PMID:10582611

  13. Overexpression of cyclin D1-CDK4 in silica-induced transformed cells is due to activation of ERKs, JNKs/AP-1 pathway.

    PubMed

    Shen, Fuhai; Fan, Xueyun; Liu, Bingci; Jia, Xiaowei; Du, Hongju; You, Baorong; Ye, Meng; Huang, Chuanshu; Shi, Xianglin

    2006-01-25

    Silica has been known to be a factor inducing acute injury and chronic pulmonary fibrosis. Silica has also been listed as a human carcinogen in 1996 by International Agency for Research on Cancer (IARC). However, the molecular mechanisms involved its pathologic effects are not well understood. In these studies, we found that exposure of human embryonic lung fibroblasts (HELF) to crystalline silica could cause increases in activation of extracellular signal-regulated kinases (ERKs), p38K, and c-Jun NH2-terminal amino kinases (JNKs), and HELF transformation. Interestingly, silica-induced transformation of HELF (S-HELF) led to increases in activated levels of ERKs and p46 of JNKs, and decrease in p38K activation, and no effect on activation of p54 of JNKs, as compared with those in parental HELF. Further studies showed that there are differential effects of ERKs, JNKs and p38K, as well as their downstream transcription factor AP-1, in regulation of expression of cyclin D1 and CDK4 and cell cycle alternations induced by silica. Cyclin D1 and CDK4 were increased in S-HELF as compared with those in HELF. Inhibition of ERKs activation by AG126, JNK by SP600125, and AP-1 by curcumin could reduced the induction of cyclin D1 and CDK4. There is no significant difference for cell cycle distribution between groups. These results demonstrate that ERKs and JNKs, but not p38K is responsible for induction of cyclin D1 and CDK4 in S-HELF, suggesting that overexpression of cyclin D1 and CDK4 caused by silica is mediated by ERK, JNK/AP-1signaling pathway. PMID:16125882

  14. A new APE1/Ref-1-dependent pathway leading to reduction of NF-kappaB and AP-1, and activation of their DNA-binding activity.

    PubMed

    Ando, Kozue; Hirao, Satoshi; Kabe, Yasuaki; Ogura, Yuji; Sato, Iwao; Yamaguchi, Yuki; Wada, Tadashi; Handa, Hiroshi

    2008-08-01

    APE1/Ref-1 is thought to be a multifunctional protein involved in reduction-oxidation (redox) regulation and base excision DNA repair, and is required for early embryonic development in mice. APE1/Ref-1 has redox activity and AP endonuclease activity, and is able to enhance DNA-binding activity of several transcription factors, including NF-kappaB, AP-1 and p53, through reduction of their critical cysteine residues. However, it remains elusive exactly how APE1/Ref-1 carries out its essential functions in vivo. Here, we show that APE1/Ref-1 not only reduces target transcription factors directly but also facilitates their reduction by other reducing molecules such as glutathione or thioredoxin. The new activity of APE1/Ref-1, termed redox chaperone activity, is exerted at concentration significantly lower than that required for its redox activity and is neither dependent on its redox activity nor on its AP endonuclease activity. We also show evidence that redox chaperone activity of APE1/Ref-1 is critical to NF-kappaB-mediated gene expression in human cells and is mediated through its physical association with target transcription factors. Thus, APE1/Ref-1 may play multiple roles in an antioxidative stress response pathway through its different biochemical activities. These findings also provide new insight into the mechanism of intracellular redox regulation. PMID:18586825

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  16. 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. PMID:23258989

  17. 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

  18. Characterization of quinolone antibacterial-induced convulsions and increases in nuclear AP-1 DNA- and CRE-binding activities in mouse brain.

    PubMed

    Ito, Y; Ishige, K; Aizawa, M; Fukuda, H

    1999-05-01

    The quinolone antibacterials enoxacin and norfloxacin (2.5 mg/kg, i.v.) provoked clonic convulsions in mice treated concomitantly with biphenylacetic acid (BPAA, 100 mg/kg, i.p.), a major metabolite of the nonsteroidal anti-inflammatory drug fenbufen. Gel-shift assays showed that enoxacin-induced convulsions resulted in increases in nuclear activator protein 1 (AP-1) DNA- and cyclic AMP responsive element (CRE)-binding activities in the cerebral cortex and hippocampus, but not in other regions, such as the cerebellum and thalamus. In contrast, ofloxacin and levofloxacin, at the same doses, in the presence of BPAA did not evoke convulsions or increase these DNA-binding activities. Administration of these quinolones and BPAA alone elicited neither convulsions nor increases in these DNA-binding activities. These results suggest that the increased nuclear AP-1 DNA- and CRE-binding activities in the cerebral cortex and hippocampus induced by quinolones with BPAA correlated with seizure activities and that these brain regions play pivotal roles in quinolone-induced convulsions. PMID:10340309

  19. Laa1p, a Conserved AP-1 Accessory Protein Important for AP-1 Localization in Yeast

    PubMed Central

    Fernández, G. Esteban

    2006-01-01

    AP-1 and Gga adaptors participate in clathrin-mediated protein transport between the trans-Golgi network and endosomes. Both adaptors contain homologous domains that act to recruit accessory proteins involved in clathrin-coated vesicle formation, but the spectrum of known adaptor-binding partners is limited. This study describes an evolutionarily conserved protein of Saccharomyces cerevisiae, Laa1p (Yjl207cp), that interacts and functions specifically with AP-1. Deletion of LAA1, when combined with a conditional mutation in clathrin heavy chain or deletion of GGA genes, accentuated growth defects and increased disruption of clathrin-dependent α-factor maturation and transport of carboxypeptidase Y to the vacuole. In contrast, such genetic interactions were not observed between deletions of LAA1 and AP-1 subunit genes. Laa1p preferentially interacted with AP-1 compared with Gga proteins by glutathione S-transferase-fusion affinity binding and coimmunoprecipitations. Localization of AP-1 and Laa1p, but not Gga proteins, was highly sensitive to brefeldin A, an inhibitor of ADP-ribosylation factor (Arf) activation. Importantly, deletion of LAA1 caused mislocalization of AP-1, especially in cells at high density (postdiauxic shift), but it did not affect Gga protein distribution. Our results identify Laa1p as a new determinant of AP-1 localization, suggesting a model in which Laa1p and Arf cooperate to direct stable association of AP-1 with appropriate intracellular membranes. PMID:16687571

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

    PubMed

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

    2014-08-01

    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. PMID:25019995

  1. 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

  2. Benzyl alcohol derivatives from the mushroom Hericium erinaceum attenuate LPS-stimulated inflammatory response through the regulation of NF-κB and AP-1 activity.

    PubMed

    Noh, Hyung Jun; Yoon, Ju Young; Kim, Geum Sook; Lee, Seung Eun; Lee, Dae Young; Choi, Je Hun; Kim, Seung Yu; Kang, Ki Sung; Cho, Jae Youl; Kim, Ki Hyun

    2014-10-01

    On the search for anti-inflammatory compounds from natural Korean medicinal sources, a bioassay-guided fractionation and chemical investigation of the MeOH extract from the fruiting bodies of Hericium erinaceum resulted in the isolation and identification of five benzyl alcohol derivatives (1-5). In this study, their anti-inflammatory effects on lipopolysaccharide (LPS)-induced production of pro-inflammatory mediators were examined using RAW 264.7 macrophage cells. The structures of isolates were identified by comparing their spectroscopic data with previously reported values. The analysis of their inhibitory activities on LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in RAW 264.7 macrophage cells showed that erinacerin B (2) and hericenone E (4) decreased the levels of NO and PGE2 production in a concentration-dependent manner. Next, this study was performed to examine their mechanism of action on the regulation of NO and PGE2 production. Compounds 2 and 4 were found to block the LPS-induced phosphorylation of two major inflammatory transcription factors, NF-κB (p65/p50) and AP-1 (c-Jun and c-Fos). Taken together, these results suggest that down-regulation of LPS-induced NO and PGE2 production by compounds 2 and 4 is mediated through the modulation of NF-κB and AP-1 activation in macrophage cells. These results impact the development of potential health products for preventing and treating inflammatory diseases. PMID:25090632

  3. Human lung and bladder carcinoma tumors as compared to their adjacent normal tissue have elevated AP-1 activity associated with the retinoblastoma gene promoter.

    PubMed

    Linardopoulos, S; Papadakis, E; Delakas, D; Theodosiou, V; Cranidis, A; Spandidos, D A

    1993-01-01

    Examination of the nucleotide sequence of the retinoblastoma (Rb) promoter revealed the presence of a DNA region highly homologous to the recognition site for the cellular transcription factor AP-1. A pair of complementary oligonucleotides containing the AP-1 site was synthesized and used in gel retardation assays to determine the role of the AP-1 protein in the regulation of the Rb gene expression. Using nuclear extracts from Hela cells as well as from lung and bladder tumors, we found specific binding of the AP-1 protein to this oligonucleotide. This binding is elevated in Hela cells, in 10/13 lung and 3/8 bladder tumors as compared to adjacent normal tissue. These results suggest that AP-1 could be implicated in Rb gene transcriptional regulation through its interaction with the AP-1 binding site of the Rb gene promoter. PMID:8476221

  4. Cutaneous wound healing through paradoxical MAPK activation by BRAF inhibitors.

    PubMed

    Escuin-Ordinas, Helena; Li, Shuoran; Xie, Michael W; Sun, Lu; Hugo, Willy; Huang, Rong Rong; Jiao, Jing; de-Faria, Felipe Meira; Realegeno, Susan; Krystofinski, Paige; Azhdam, Ariel; Komenan, Sara Marie D; Atefi, Mohammad; Comin-Anduix, Begoña; Pellegrini, Matteo; Cochran, Alistair J; Modlin, Robert L; Herschman, Harvey R; Lo, Roger S; McBride, William H; Segura, Tatiana; Ribas, Antoni

    2016-01-01

    BRAF inhibitors are highly effective therapies for the treatment of BRAF(V600)-mutated melanoma, with the main toxicity being a variety of hyperproliferative skin conditions due to paradoxical activation of the mitogen-activated protein kinase (MAPK) pathway in BRAF wild-type cells. Most of these hyperproliferative skin changes improve when a MEK inhibitor is co-administered, as it blocks paradoxical MAPK activation. Here we show how the BRAF inhibitor vemurafenib accelerates skin wound healing by inducing the proliferation and migration of human keratinocytes through extracellular signal-regulated kinase (ERK) phosphorylation and cell cycle progression. Topical treatment with vemurafenib in two wound-healing mice models accelerates cutaneous wound healing through paradoxical MAPK activation; addition of a mitogen-activated protein kinase kinase (MEK) inhibitor reverses the benefit of vemurafenib-accelerated wound healing. The same dosing regimen of topical BRAF inhibitor does not increase the incidence of cutaneous squamous cell carcinomas in mice. Therefore, topical BRAF inhibitors may have clinical applications in accelerating the healing of skin wounds. PMID:27476449

  5. Cutaneous wound healing through paradoxical MAPK activation by BRAF inhibitors

    PubMed Central

    Escuin-Ordinas, Helena; Li, Shuoran; Xie, Michael W.; Sun, Lu; Hugo, Willy; Huang, Rong Rong; Jiao, Jing; de-Faria, Felipe Meira; Realegeno, Susan; Krystofinski, Paige; Azhdam, Ariel; Komenan, Sara Marie D.; Atefi, Mohammad; Comin-Anduix, Begoña; Pellegrini, Matteo; Cochran, Alistair J.; Modlin, Robert L.; Herschman, Harvey R.; Lo, Roger S.; McBride, William H.; Segura, Tatiana; Ribas, Antoni

    2016-01-01

    BRAF inhibitors are highly effective therapies for the treatment of BRAFV600-mutated melanoma, with the main toxicity being a variety of hyperproliferative skin conditions due to paradoxical activation of the mitogen-activated protein kinase (MAPK) pathway in BRAF wild-type cells. Most of these hyperproliferative skin changes improve when a MEK inhibitor is co-administered, as it blocks paradoxical MAPK activation. Here we show how the BRAF inhibitor vemurafenib accelerates skin wound healing by inducing the proliferation and migration of human keratinocytes through extracellular signal-regulated kinase (ERK) phosphorylation and cell cycle progression. Topical treatment with vemurafenib in two wound-healing mice models accelerates cutaneous wound healing through paradoxical MAPK activation; addition of a mitogen-activated protein kinase kinase (MEK) inhibitor reverses the benefit of vemurafenib-accelerated wound healing. The same dosing regimen of topical BRAF inhibitor does not increase the incidence of cutaneous squamous cell carcinomas in mice. Therefore, topical BRAF inhibitors may have clinical applications in accelerating the healing of skin wounds. PMID:27476449

  6. 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. PMID:21474329

  7. p38γ and p38δ Mitogen Activated Protein Kinases (MAPKs), New Stars in the MAPK Galaxy

    PubMed Central

    Escós, Alejandra; Risco, Ana; Alsina-Beauchamp, Dayanira; Cuenda, Ana

    2016-01-01

    The protein kinases p38γ and p38δ belong to the p38 mitogen-activated protein kinase (MAPK) family. p38MAPK signaling controls many cellular processes and is one of the most conserved mechanisms in eukaryotes for the cellular response to environmental stress and inflammation. Although p38γ and p38δ are widely expressed, it is likely that they perform specific functions in different tissues. Their involvement in human pathologies such as inflammation-related diseases or cancer is starting to be uncovered. In this article we give a general overview and highlight recent advances made in defining the functions of p38γ and p38δ, focusing in innate immunity and inflammation. We consider the potential of the pharmacological targeting of MAPK pathways to treat autoimmune and inflammatory diseases and cancer. PMID:27148533

  8. CR3 and Dectin-1 Collaborate in Macrophage Cytokine Response through Association on Lipid Rafts and Activation of Syk-JNK-AP-1 Pathway.

    PubMed

    Huang, Juin-Hua; Lin, Ching-Yu; Wu, Sheng-Yang; Chen, Wen-Yu; Chu, Ching-Liang; Brown, Gordon D; Chuu, Chih-Pin; Wu-Hsieh, Betty A

    2015-07-01

    Collaboration between heterogeneous pattern recognition receptors (PRRs) leading to synergistic coordination of immune response is important for the host to fight against invading pathogens. Although complement receptor 3 (CR3) and Dectin-1 are major PRRs to detect fungi, crosstalk between these two receptors in antifungal immunity is largely undefined. Here we took advantage of Histoplasma capsulatum which is known to interact with both CR3 and Dectin-1 and specific particulate ligands to study the collaboration of CR3 and Dectin-1 in macrophage cytokine response. By employing Micro-Western Array (MWA), genetic approach, and pharmacological inhibitors, we demonstrated that CR3 and Dectin-1 act collaboratively to trigger macrophage TNF and IL-6 response through signaling integration at Syk kinase, allowing subsequent enhanced activation of Syk-JNK-AP-1 pathway. Upon engagement, CR3 and Dectin-1 colocalize and form clusters on lipid raft microdomains which serve as a platform facilitating their cooperation in signaling activation and cytokine production. Furthermore, in vivo studies showed that CR3 and Dectin-1 cooperatively participate in host defense against disseminated histoplasmosis and instruct adaptive immune response. Taken together, our findings define the mechanism of receptor crosstalk between CR3 and Dectin-1 and demonstrate the importance of their collaboration in host defense against fungal infection. PMID:26132276

  9. Nanofiber diameter-dependent MAPK activity in osteoblasts.

    PubMed

    Jaiswal, Devina; Brown, Justin L

    2012-11-01

    The major challenge for bone tissue engineering lies in the fabrication of scaffolds that can mimic the extracellular matrix and promote osteogenesis. Electrospun fibers are being widely researched for this application due to high porosity, interconnectivity, and mechanical strength of the fibrous scaffolds. Electrospun poly methyl methacrylate (PMMA, 2.416 ± 0.100 μm) fibers were fabricated and etched using a 60% propylene glycol methyl ether acetate (PGMEA)/limonene (vol/vol) solution to obtain fiber diameters ranging from 2.5 to 0.5 μm in a time-dependent manner. The morphology of the fibrous scaffolds was evaluated using scanning electron microscopy and cellular compatibility with etchant-treated scaffold was assessed using immunoflurescence. Mitogen-activated protein kinases (MAPK) activation in response to different fiber diameter was evaluated with western blot as well as quantitative in-cell western. We report that electrospun micro-fibers can be etched to 0.552 ± 0.047 μm diameter without producing beads. Osteoblasts adhered to the fibers and a change in fiber diameter played a major role in modulating the activation of extracellular signal-regulated kinase (ERK) and p38 kinases with 0.882 ± 0.091 μm diameter fibers producing an inverse effect on ERK and p38 phosphorylation. These results indicate that nanofibers produced by wet etching can be effectively utilized to produce diameters that can differentially modulate MAPK activation patterns. PMID:22700490

  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. PMID:26948281

  11. 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

  12. 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

  13. Evidence for the Involvement of p38 MAPK Activation in Barnacle Larval Settlement

    PubMed Central

    He, Li-Sheng; Xu, Ying; Matsumura, Kiyotaka; Zhang, Yu; Zhang, Gen; Qi, Shu-Hua; Qian, Pei-Yuan

    2012-01-01

    The barnacle Balanus ( = Amphibalanus) amphitrite is a major marine fouling animal. Understanding the molecular mechanism of larval settlement in this species is critical for anti-fouling research. In this study, we cloned one isoform of p38 MAPK (Bar-p38 MAPK) from this species, which shares the significant characteristic of containing a TGY motif with other species such as yeast, Drosophila and humans. The activation of p38 MAPK was detected by an antibody that recognizes the conserved dual phosphorylation sites of TGY. The results showed that phospho-p38 MAPK (pp38 MAPK) was more highly expressed at the cyprid stage, particularly in aged cyprids, in comparison to other stages, including the nauplius and juvenile stages. Immunostaining showed that Bar-p38 MAPK and pp38 MAPK were mainly located at the cyprid antennules, and especially the third and fourth segments, which are responsible for substratum exploration during settlement. The expression and localization patterns of Bar-p38 MAPK suggest its involvement in larval settlement. This postulation was also supported by the larval settlement bioassay with the p38 MAPK inhibitor SB203580. Behavioral analysis by live imaging revealed that the larvae were still capable of exploring the surface of the substratum after SB203580 treatment. This shows that the effect of p38 MAPK on larval settlement might be by regulating the secretion of permanent proteinaceous substances. Furthermore, the level of pp38 MAPK dramatically decreased after full settlement, suggesting that Bar-p38 MAPK maybe plays a role in larval settlement rather than metamorphosis. Finally, we found that Bar-p38 MAPK was highly activated when larvae confronted extracts of adult barnacle containing settlement cues, whereas larvae pre-treated with SB203580 failed to respond to the crude adult extracts. PMID:23115639

  14. 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 Central

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

    2013-01-01

    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. PMID:24025361

  15. 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. PMID:24025361

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  17. Characterization of the human granulocyte-macrophage colony-stimulating factor gene promoter: an AP1 complex and an Sp1-related complex transactivate the promoter activity that is suppressed by a YY1 complex.

    PubMed Central

    Ye, J; Zhang, X; Dong, Z

    1996-01-01

    It is well documented that a repeated CATT element in the human granulocyte-macrophage colony-stimulating factor (GM-CSF) gene promoter is required for promoter activity. However, the transcription factors that are able to transactivate this enhancer element remain unidentified. Recently, we have found that nuclear factor YY1 can interact with the enhancer element. Here, we report that in addition to YY1, two other nuclear factors have been identified in the DNA-protein complexes formed by the CATT oligonucleotide and the Jurkat T-cell nuclear protein. One of these factors is AP1, and the other one is an Sp1-related protein. Results from transient transfection of Jurkat T cells have revealed that formation of both AP1 and the Sp1-related complex is required for the full enhancer activity of the CATT element. This result is supported by cotransfection of a c-jun expression vector and mutational analysis of the AP1 site or the Sp1-related protein binding site. In contrast, formation of the YY1 complex suppresses enhancer activity, since deletion of the YY1 complex induces an augmentation of the enhancer activity and overexpression of YY1 results in an attenuation of the enhancer activity. Results from the mechanism study have revealed that YY1 is able to inhibit transactivation mediated by either AP1 or the Sp1-related protein, and YY1 suppressive activity is DNA binding dependent. Taken together, these data support the ideas that AP1 and the Sp1-related nuclear protein are required for transactivation of the human GM-CSF gene promoter and that YY1 can suppress transactivation of the promoter even under inducible conditions. PMID:8524292

  18. Identification, Nomenclature, and Evolutionary Relationships of Mitogen-Activated Protein Kinase (MAPK) Genes in Soybean

    PubMed Central

    Neupane, Achal; Nepal, Madhav P.; Piya, Sarbottam; Subramanian, Senthil; Rohila, Jai S.; Reese, R. Neil; Benson, Benjamin V.

    2013-01-01

    Mitogen-activated protein kinase (MAPK) genes in eukaryotes regulate various developmental and physiological processes including those associated with biotic and abiotic stresses. Although MAPKs in some plant species including Arabidopsis have been identified, they are yet to be identified in soybean. Major objectives of this study were to identify GmMAPKs, assess their evolutionary relationships, and analyze their functional divergence. We identified a total of 38 MAPKs, eleven MAPKKs, and 150 MAPKKKs in soybean. Within the GmMAPK family, we also identified a new clade of six genes: four genes with TEY and two genes with TQY motifs requiring further investigation into possible legume-specific functions. The results indicated the expansion of the GmMAPK families attributable to the ancestral polyploidy events followed by chromosomal rearrangements. The GmMAPK and GmMAPKKK families were substantially larger than those in other plant species. The duplicated GmMAPK members presented complex evolutionary relationships and functional divergence when compared to their counterparts in Arabidopsis. We also highlighted existing nomenclatural issues, stressing the need for nomenclatural consistency. GmMAPK identification is vital to soybean crop improvement, and novel insights into the evolutionary relationships will enhance our understanding about plant genome evolution. PMID:24137047

  19. Hypertonic saline activation of p38 MAPK primes the PMN respiratory burst.

    PubMed

    Ciesla, D J; Moore, E E; Biffl, W L; Gonzalez, R J; Moore, H B; Silliman, C C

    2001-10-01

    Investigation of hypertonic saline (HTS) modulation of neutrophils (PMN) cytotoxic responses has generated seemingly contradictory results. Clinically relevant levels of HTS attenuate receptor-mediated p38 MAPK signaling, whereas higher levels activate p38 MAPK. Concurrently, HTS exerts a dose-dependent attenuation of the PMN respiratory burst, most notably at concentrations where p38 MAPK is activated. We hypothesized that HTS-mediated p38 MAPK activation augments the PMN respiratory burst on return to normotonicity. We found that although clinically relevant levels of HTS (Na+ > or = 200 mM) did not activate p38 MAPK, higher concentrations (Na+ > or = 300 mM) resulted in activation comparable with that after PAF stimulation. Transient stimulation with high levels of HTS primed the PMN respiratory burst in response to fMLP and PMA. This effect was attenuated by pretreatment with SB 203580, a p38 MAPK specific inhibitor. We conclude that severe osmotic shock primes the respiratory burst via p38 MAPK signaling, further supporting the role of this signaling cascade in PMN priming. PMID:11580111

  20. Ras-GTP dimers activate the Mitogen-Activated Protein Kinase (MAPK) pathway

    PubMed Central

    Nan, Xiaolin; Tamgüney, Tanja M.; Collisson, Eric A.; Lin, Li-Jung; Pitt, Cameron; Galeas, Jacqueline; Lewis, Sophia; Gray, Joe W.; McCormick, Frank; Chu, Steven

    2015-01-01

    Rat sarcoma (Ras) GTPases regulate cell proliferation and survival through effector pathways including Raf-MAPK, and are the most frequently mutated genes in human cancer. Although it is well established that Ras activity requires binding to both GTP and the membrane, details of how Ras operates on the cell membrane to activate its effectors remain elusive. Efforts to target mutant Ras in human cancers to therapeutic benefit have also been largely unsuccessful. Here we show that Ras-GTP forms dimers to activate MAPK. We used quantitative photoactivated localization microscopy (PALM) to analyze the nanoscale spatial organization of PAmCherry1-tagged KRas 4B (hereafter referred to KRas) on the cell membrane under various signaling conditions. We found that at endogenous expression levels KRas forms dimers, and KRasG12D, a mutant that constitutively binds GTP, activates MAPK. Overexpression of KRas leads to formation of higher order Ras nanoclusters. Conversely, at lower expression levels, KRasG12D is monomeric and activates MAPK only when artificially dimerized. Moreover, dimerization and signaling of KRas are both dependent on an intact CAAX (C, cysteine; A, aliphatic; X, any amino acid) motif that is also known to mediate membrane localization. These results reveal a new, dimerization-dependent signaling mechanism of Ras, and suggest Ras dimers as a potential therapeutic target in mutant Ras-driven tumors. PMID:26080442

  1. Ras-GTP dimers activate the mitogen-activated protein kinase (MAPK) pathway

    DOE PAGESBeta

    Nan, Xiaolin; Tamgüney, Tanja M.; Collisson, Eric A.; Lin, Li -Jung; Pitt, Cameron; Galeas, Jacqueline; Lewis, Sophia; Gray, Joe W.; McCormick, Frank; Chu, Steven

    2015-06-16

    Rat sarcoma (Ras) GTPases regulate cell proliferation and survival through effector pathways including Raf-MAPK, and are the most frequently mutated genes in human cancer. Although it is well established that Ras activity requires binding to both GTP and the membrane, details of how Ras operates on the cell membrane to activate its effectors remain elusive. Efforts to target mutant Ras in human cancers to therapeutic benefit have also been largely unsuccessful. Here we show that Ras-GTP forms dimers to activate MAPK. We used quantitative photoactivated localization microscopy (PALM) to analyze the nanoscale spatial organization of PAmCherry1-tagged KRas 4B (hereafter referredmore » to KRas) on the cell membrane under various signaling conditions. We found that at endogenous expression levels KRas forms dimers, and KRasG12D, a mutant that constitutively binds GTP, activates MAPK. Overexpression of KRas leads to formation of higher order Ras nanoclusters. Conversely, at lower expression levels, KRasG12D is monomeric and activates MAPK only when artificially dimerized. Moreover, dimerization and signaling of KRas are both dependent on an intact CAAX (C, cysteine; A, aliphatic; X, any amino acid) motif that is also known to mediate membrane localization. These results reveal a new, dimerization-dependent signaling mechanism of Ras, and suggest Ras dimers as a potential therapeutic target in mutant Ras-driven tumors.« less

  2. Ras-GTP dimers activate the mitogen-activated protein kinase (MAPK) pathway

    SciTech Connect

    Nan, Xiaolin; Tamgüney, Tanja M.; Collisson, Eric A.; Lin, Li -Jung; Pitt, Cameron; Galeas, Jacqueline; Lewis, Sophia; Gray, Joe W.; McCormick, Frank; Chu, Steven

    2015-06-16

    Rat sarcoma (Ras) GTPases regulate cell proliferation and survival through effector pathways including Raf-MAPK, and are the most frequently mutated genes in human cancer. Although it is well established that Ras activity requires binding to both GTP and the membrane, details of how Ras operates on the cell membrane to activate its effectors remain elusive. Efforts to target mutant Ras in human cancers to therapeutic benefit have also been largely unsuccessful. Here we show that Ras-GTP forms dimers to activate MAPK. We used quantitative photoactivated localization microscopy (PALM) to analyze the nanoscale spatial organization of PAmCherry1-tagged KRas 4B (hereafter referred to KRas) on the cell membrane under various signaling conditions. We found that at endogenous expression levels KRas forms dimers, and KRasG12D, a mutant that constitutively binds GTP, activates MAPK. Overexpression of KRas leads to formation of higher order Ras nanoclusters. Conversely, at lower expression levels, KRasG12D is monomeric and activates MAPK only when artificially dimerized. Moreover, dimerization and signaling of KRas are both dependent on an intact CAAX (C, cysteine; A, aliphatic; X, any amino acid) motif that is also known to mediate membrane localization. These results reveal a new, dimerization-dependent signaling mechanism of Ras, and suggest Ras dimers as a potential therapeutic target in mutant Ras-driven tumors.

  3. 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 Central

    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. PMID:26367267

  4. 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. PMID:26367267

  5. An Estrogen Receptor-α/p300 Complex Activates the BRCA-1 Promoter at an AP-1 Site That Binds Jun/Fos Transcription Factors: Repressive Effects of p53 on BRCA-1 Transcription1

    PubMed Central

    Jeffy, Brandon D; Hockings, Jennifer K; Kemp, Michael Q; Morgan, Sherif S; Hager, Jill A; Beliakoff, Jason; Whitesell, Luke J; Bowden, G. Timothy; Romagnolo, Donato F

    2005-01-01

    Abstract One of the puzzles in cancer predisposition is that women carrying BRCA-1 mutations preferentially develop tumors in epithelial tissues of the breast and ovary. Moreover, sporadic breast tumors contain lower levels of BRCA-1 in the absence of mutations in the BRCA-1 gene. The problem of tissue specificity requires analysis of factors that are unique to tissues of the breast. For example, the expression of estrogen receptor-α (ERα) is inversely correlated with breast cancer risk, and 90% of BRCA-1 tumors are negative for ERα. Here, we show that estrogen stimulates BRCA-1 promoter activity in transfected cells and the recruitment of ERα and its cofactor p300 to an AP-1 site that binds Jun/Fos transcription factors. The recruitment of ERα/p300 coincides with accumulation in the S-phase of the cell cycle and is antagonized by the antiestrogen tamoxifen. Conversely, we document that overexpression of wild-type p53 prevents the recruitment of ERα to the AP-1 site and represses BRCA-1 promoter activity. Taken together, our findings support a model in which an ERα/AP-1 complex modulates BRCA-1 transcription under conditions of estrogen stimulation. Conversely, the formation of this transcription complex is abrogated in cells overexpressing p53. PMID:16229810

  6. Nucleolin binds specifically to an AP-1 DNA sequence and represses AP1-dependent transactivation of the matrix metalloproteinase-13 gene.

    PubMed

    Samuel, Shaija; Twizere, Jean-Claude; Beifuss, Katherine K; Bernstein, Lori R

    2008-01-01

    Transcriptional regulation via activator protein-1 (AP-1) protein binding to AP-1 binding sites within gene promoter regions of AP-1 target genes plays a key role in controlling cellular invasion, proliferation, and oncogenesis, and is important to pathogenesis of arthritis and cardiovascular disease. To identify new proteins that interact with the AP-1 DNA binding site, we performed the DNA affinity chromatography-based Nucleotide Affinity Preincubation Specificity TEst of Recognition (NAPSTER) assay, and discovered a 97 kDa protein that binds in vitro to a minimal AP-1 DNA sequence element. Mass spectrometric fragmentation sequencing determined that p97 is nucleolin. Immunoblotting of DNA affinity-purified material with anti-nucleolin antibodies confirmed this identification. Nucleolin also binds the AP-1 site in gel shift assays. Nucleolin interacts in NAPSTER with the AP-1 site within the promoter sequence of the metalloproteinase-13 gene (MMP-13), and binds in vivo in chromatin immunoprecipitation assays in the vicinity of the AP-1 site in the MMP-13 promoter. Overexpression of nucleolin in human HeLa cervical carcinoma cells significantly represses AP-1 dependent gene transactivation of a minimal AP-1 reporter construct and of an MMP-13 promoter reporter sequence. This is the first report of nucleolin binding and transregulation at the AP-1 site. PMID:17626252

  7. Reciprocal effects of varicella-zoster virus (VZV) and AP1: activation of jun, fos and ATF-2 after VZV infection and their importance for the regulation of viral genes.

    PubMed

    Rahaus, Markus; Wolff, Manfred H

    2003-03-01

    Varicella-zoster virus, an alpha-herpesvirus that is pathogenic for man, encodes its own transcription activators, but ubiquitous cellular transcription factors are of great importance, too. Performing quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) we found an increase of transcription of AP1 components jun, fos and of ATF-2 at different times post infection (p.i.). Jun and ATF-2 proteins were detected in infected cells. To study general effects of AP1 in the regulation of VZV encoded genes, oligonucleotide transfections were performed to knockout jun and ATF-2 transcription followed by infection with cell free VZV. RT-PCR analyses of ORFs 4, 9, 21, 29 and 68 belonging to all three kinetic classes of genes and containing different combinations of AP1/TRE and ATF/CREB sites in their respective promoters were carried out. In all cases a reduction of viral transcription was found. Virions produced after this procedure were still infectious, but the amount of newly synthesized virions was clearly reduced. PMID:12606072

  8. Id-1 is induced in MDCK epithelial cells by activated Erk/MAPK pathway in response to expression of the Snail and E47 transcription factors

    SciTech Connect

    Jorda, Mireia; Vinyals, Antonia; Marazuela, Anna; Cubillo, Eva; Olmeda, David; Valero, Eva; Cano, Amparo; Fabra, Angels . E-mail: afabra@idibell.org

    2007-07-01

    Id-1, a member of the helix-loop-helix transcription factor family has been shown to be involved in cell proliferation, angiogenesis and invasion of many types of human cancers. We have previously shown that stable expression of E47 and Snail repressors of the E-cadherin promoter in MDCK epithelial cell line triggers epithelial mesenchymal transition (EMT) concomitantly with changes in gene expression. We show here that both factors activate the Id-1 gene promoter and induce Id-1 mRNA and protein. The upregulation of the Id-1 gene occurs through the transactivation of the promoter by the Erk/MAPK signaling pathway. Moreover, oncogenic Ras is also able to activate Id-1 promoter in MDCK cells in the absence of both E47 and Snail transcription factors. Several transcriptionally active regulatory elements have been identified in the proximal promoter, including AP-1, Sp1 and four putative E-boxes. By EMSA, we only detected an increased binding to Sp1 and AP-1 elements in E47- and Snail-expressing cells. Binding is affected by the treatment of cells with PD 98059 MEK inhibitor, suggesting that MAPK/Erk contributes to the recruitment or assembly of proteins to Id-1 promoter. Small interfering RNA directed against Sp1 reduced Id-1 expression and the upregulation of the promoter, indicating that Sp1 is required for Id-1 induction in E47- and Snail-expressing cells. Our results provide new insights into how some target genes are activated during and/or as a consequence of the EMT triggered by both E47 and Snail transcription factors.

  9. Molecular Changes Involving MEK3-p38 MAPK Activation in Chronic Masticatory Myalgia.

    PubMed

    Meng, H; Gao, Y; Kang, Y F; Zhao, Y P; Yang, G J; Wang, Y; Cao, Y; Gan, Y H; Xie, Q F

    2016-09-01

    The exact mechanism underlying chronic masticatory myalgia (CMM), a conspicuous symptom in temporomandibular disorders, remains unclear. This investigation compared gene expression profiles between CMM patients and healthy subjects. Peripheral blood leukocytes were collected in 8 cases and 8 controls and subjected to whole genome microarray analyses. Data were analyzed with Gene Ontology and interactive pathways analyses. According to Gene Ontology analysis, categories such as ion transport, response to stimuli, and metabolic process were upregulated. The pathway analysis suggested overexpression of the mitogen-activated protein kinase (MAPK) pathway in CMM patients and to a higher degree in a pathway network. Overexpression of representative members of the MAPK pathway-including MAPK kinase 3 (MEK3), calcium voltage-gated channel auxiliary subunit gamma 2 (CACNG2), and growth arrest and DNA damage-inducible gamma (GADD45G)-was validated with real-time polymerase chain reaction. The upregulation of MEK3 was negatively correlated with the age of the CMM group. In the next step, the authors focused on MEK3, the gene that exhibited the greatest degree of differential expression, and its downstream target protein p38 MAPK. The results revealed upregulation of MEK3, as well as phosphorylated MEK3 and phosphorylated p38 MAPK, in CMM patients. These results provide a "fingerprint" for mechanistic studies of CMM in the future and highlight the importance of MEK3-p38 MAPK activation in CMM. PMID:27418173

  10. Phosphatidylserine enhances IKBKAP transcription by activating the MAPK/ERK signaling pathway.

    PubMed

    Donyo, Maya; Hollander, Dror; Abramovitch, Ziv; Naftelberg, Shiran; Ast, Gil

    2016-04-01

    Familial dysautonomia (FD) is a genetic disorder manifested due to abnormal development and progressive degeneration of the sensory and autonomic nervous system. FD is caused by a point mutation in the IKBKAP gene encoding the IKAP protein, resulting in decreased protein levels. A promising potential treatment for FD is phosphatidylserine (PS); however, the manner by which PS elevates IKAP levels has yet to be identified. Analysis of ChIP-seq results of the IKBKAP promoter region revealed binding of the transcription factors CREB and ELK1, which are regulated by the mitogen-activated protein kinase (MAPK)/extracellular-regulated kinase (ERK) signaling pathway. We show that PS treatment enhanced ERK phosphorylation in cells derived from FD patients. ERK activation resulted in elevated IKBKAP transcription and IKAP protein levels, whereas pretreatment with the MAPK inhibitor U0126 blocked elevation of the IKAP protein level. Overexpression of either ELK1 or CREB activated the IKBKAP promoter, whereas downregulation of these transcription factors resulted in a decrease of the IKAP protein. Additionally, we show that PS improves cell migration, known to be enhanced by MAPK/ERK activation and abrogated in FD cells. In conclusion, our results demonstrate that PS activates the MAPK/ERK signaling pathway, resulting in activation of transcription factors that bind the promoter region of IKBKAP and thus enhancing its transcription. Therefore, compounds that activate the MAPK/ERK signaling pathway could constitute potential treatments for FD. PMID:26769675

  11. A functional activating protein 1 (AP-1) site regulates matrix metalloproteinase 2 (MMP-2) transcription by cardiac cells through interactions with JunB-Fra1 and JunB-FosB heterodimers.

    PubMed Central

    Bergman, Marina R; Cheng, Sunfa; Honbo, Norman; Piacentini, Lucia; Karliner, Joel S; Lovett, David H

    2003-01-01

    Enhanced synthesis of a specific matrix metalloproteinase, MMP-2, has been demonstrated in experimental models of ventricular failure and in cardiac extracts from patients with ischaemic cardiomyopathy. Cultured neonatal rat cardiac fibroblasts and myocytes were used to analyse the determinants of MMP-2 synthesis, including the effects of hypoxia. Culture of rat cardiac fibroblasts for 24 h in 1% oxygen enhanced MMP-2 synthesis by more than 5-fold and augmented the MMP-2 synthetic responses of these cells to endothelin-1, angiotensin II and interleukin 1beta. A series of MMP-2 promoter-luciferase constructs were used to map the specific enhancer element(s) that drive MMP-2 transcription in cardiac cells. Deletion studies mapped a region of potent transactivating function within the 91 bp region from -1433 to -1342 bp, the activity of which was increased by hypoxia. Oligonucleotides from this region were cloned in front of a heterologous simian-virus-40 (SV40) promoter and mapped the enhancer activity to a region between -1410 and -1362 bp that included a potential activating protein 1 (AP-1)-binding sequence, C(-1394)CTGACCTCC. Site-specific mutagenesis of the core TGAC sequence (indicated in bold) eliminated the transactivating activity within the -1410 to -1362 bp sequence. Electrophoretic mobility shift assays (EMSAs) using the -1410 to -1362 bp oligonucleotide and rat cardiac fibroblast nuclear extracts demonstrated specific nuclear-protein binding that was eliminated by cold competitor oligonucleotide, but not by the AP-1-mutated oligonucleotide. Antibody-supershift EMSAs of nuclear extracts from normoxic rat cardiac fibroblasts demonstrated Fra1 and JunB binding to the -1410 to -1362 bp oligonucleotide. Nuclear extracts isolated from hypoxic rat cardiac fibroblasts contained Fra1, JunB and also included FosB. Co-transfection of cardiac fibroblasts with Fra1-JunB and FosB-JunB expression plasmids led to significant increases in transcriptional activity. These

  12. Hepatocyte cytoskeleton during ischemia and reperfusion - influence of ANP-mediated p38 MAPK activation

    PubMed Central

    Keller, Melanie; Gerbes, Alexander L; Kulhanek-Heinze, Stefanie; Gerwig, Tobias; Grützner, Uwe; van Rooijen, Nico; Vollmar, Angelika M; Kiemer, Alexandra K

    2005-01-01

    AIM: To determine functional consequences of this activation, whereby we focused on a potential regulation of the hepatocyte cytoskeleton during ischemia and reperfusion. METHODS: For in vivo experiments, animals received ANP (5 μg/kg) intravenously. In a different experimental setting, isolated rat livers were perfused with KH-buffer±ANP (200 nmol/L)±SB203580 (2 μmol/L). Livers were then kept under ischemic conditions for 24 h, and either transplanted or reperfused. Actin, Hsp27, and phosphorylated Hsp27 were determined by Western blotting, p38 MAPK activity by in vitro phosphorylation assay. F-actin distribution was determined by confocal microscopy. RESULTS: We first confirmed that ANP preconditioning leads to an activation of p38 MAPK and observed alterations of the cytoskeleton in hepatocytes of ANP-preconditioned organs. ANP induced an increase of hepatic F-actin after ischemia, which could be prevented by the p38 MAPK inhibitor SB203580 but had no effect on bile flow. After ischemia untreated livers showed a translocation of Hsp27 towards the cytoskeleton and an increase in total Hsp27, whereas ANP preconditioning prohibited translocation but caused an augmentation of Hsp27 phosphorylation. This effect is also mediated via p38 MAPK, since it was abrogated by the p38 MAPK inhibitor SB203580. CONCLUSION: This study reveals that ANP-mediated p38 MAPK activation leads to changes in hepatocyte cytoskeleton involving an elevation of phosphorylated Hsp27 and thereby for the first time shows functional consequences of ANP-induced hepatic p38 MAPK activation. PMID:16437711

  13. Suppression of B-Raf(V600E) cancers by MAPK hyper-activation

    PubMed Central

    Eldad, Sophia; Smeir, Elia; Bar-Tana, Jacob

    2016-01-01

    B-Raf(V600E) activates MEK/MAPK signalling and acts as oncogenic driver of a variety of cancers, including melanoma, colorectal and papillary thyroid carcinoma. Specific B-Raf(V600E) kinase inhibitors (e.g., Vemurafenib) prove initial efficacy in melanoma followed shortly by acquired resistance, while failing in most other B-Raf(V600E) cancers due to primary resistance. Resistance is due to acquired mutations in the Ras/Raf/MEK/MAPK pathway and/or other oncogenic drivers that bypass B-Raf(V600E). Surprisingly, hyper-activation of MAPK by inhibiting its protein phosphatase 2A by a synthetic long-chain fatty acid analogue (MEDICA), results in oncogene-induced growth arrest and apoptosis of B-Raf(V600E) cancer cells. Growth arrest is accompanied by MAPK-mediated serine/threonine phosphorylation and suppression of a variety of oncogenic drivers that resist treatment by B-Raf(V600E) kinase inhibitors, including ErbB members, c-Met, IGFR, IRS, STAT3 and Akt. The combined activities of mutated B-Raf and MEDICA are required for generating hyper-activated MAPK, growth arrest and apoptosis, implying strict specificity for mutated B-Raf cancer cells. PMID:26959890

  14. Suppression of B-Raf(V600E) cancers by MAPK hyper-activation.

    PubMed

    Atiq, Rawan; Hertz, Rachel; Eldad, Sophia; Smeir, Elia; Bar-Tana, Jacob

    2016-04-01

    B-Raf(V600E) activates MEK/MAPK signalling and acts as oncogenic driver of a variety of cancers, including melanoma, colorectal and papillary thyroid carcinoma. Specific B-Raf(V600E) kinase inhibitors (e.g., Vemurafenib) prove initial efficacy in melanoma followed shortly by acquired resistance, while failing in most other B-Raf(V600E) cancers due to primary resistance. Resistance is due to acquired mutations in the Ras/Raf/MEK/MAPK pathway and/or other oncogenic drivers that bypass B-Raf(V600E). Surprisingly, hyper-activation of MAPK by inhibiting its protein phosphatase 2A by a synthetic long-chain fatty acid analogue (MEDICA), results in oncogene-induced growth arrest and apoptosis of B-Raf(V600E) cancer cells. Growth arrest is accompanied by MAPK-mediated serine/threonine phosphorylation and suppression of a variety of oncogenic drivers that resist treatment by B-Raf(V600E) kinase inhibitors, including ErbB members, c-Met, IGFR, IRS, STAT3 and Akt. The combined activities of mutated B-Raf and MEDICA are required for generating hyper-activated MAPK, growth arrest and apoptosis, implying strict specificity for mutated B-Raf cancer cells. PMID:26959890

  15. 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. PMID:25762639

  16. 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 Central

    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 anti-cancer 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 AP1 transcriptional activity and nuclear translocation of 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. PMID:24191894

  17. 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.

  18. Celastrol ameliorates HIV-1 Tat-induced inflammatory responses via NF-kappaB and AP-1 inhibition and heme oxygenase-1 induction in astrocytes

    SciTech Connect

    Youn, Gi Soo; Kwon, Dong-Joo; Ju, Sung Mi; Rhim, Hyangshuk; Bae, Yong Soo; Choi, Soo Young; Park, Jinseu

    2014-10-01

    HIV-1 Tat causes extensive neuroinflammation that may progress to AIDS-related encephalitis and dementia. Celastrol possesses various biological activities such as anti-oxidant, anti-tumor, and anti-inflammatory activities. In this study, we investigated the modulatory effects of celastrol on HIV-1 Tat-induced inflammatory responses and the molecular mechanisms underlying its action in astrocytes. Pre-treatment of CRT-MG human astroglioma cells with celastrol significantly inhibited HIV-1 Tat-induced expression of ICAM-1/VCAM-1 and subsequent monocyte adhesiveness in CRT-MG cells. In addition, celastrol suppressed HIV-1 Tat-induced expression of pro-inflammatory chemokines, such as CXCL10, IL-8, and MCP-1. Celastrol decreased HIV-1 Tat-induced activation of JNK MAPK, AP-1, and NF-κB. Furthermore, celastrol induced mRNA and protein expression of HO-1 as well as Nrf2 activation. Blockage of HO-1 expression using siRNA reversed the inhibitory effect of celastrol on HIV-1 Tat-induced inflammatory responses. These results suggest that celastrol has regulatory effects on HIV-1 Tat-induced inflammatory responses by blocking the JNK MAPK-AP-1/NF-κB signaling pathways and inducing HO-1 expression in astrocytes. - Highlights: • Celastrol suppressed HIV-1 Tat-induced expression of pro-inflammatory genes. • Celastrol inhibited HIV-1 Tat -induced activation of JNK MAPK. • Celastrol inhibited HIV-1 Tat-induced activation of both NF-κB and AP-1. • Celastrol inhibited HIV-1 Tat-induced inflammatory responses via HO-1 induction.

  19. The PHD motif of Map3k1 activates cytokine-dependent MAPK signaling

    PubMed Central

    Gallagher, Ewen; Suddason, Tesha

    2015-01-01

    We generated a mutation in the gene encoding mitogen-activated protein kinase kinase kinase 1 (Map3k1) that results in a protein with an inactive plant homeodomain (PHD). Map3k1mPHD cells are defective in cytokine-mediated MAPK signaling. Protein array identified transforming growth factor (TGF-β)-activated kinase 1 binding protein 1 (Tab1) as a PHD substrate. The Map3k1 PHD transfers Lys63-linked poly-ubiquitin onto Tab1 to activate MAPKs. PMID:27308457

  20. MKK3 was involved in larval settlement of the barnacle Amphibalanus amphitrite through activating the kinase activity of p38MAPK.

    PubMed

    Zhang, Gen; He, Li-Sheng; Wong, Yue Him; Qian, Pei-Yuan

    2013-01-01

    The p38 mitogen-activated protein kinase (p38MAPK) plays a key role in larval settlement of the barnacle Amphibalanus amphitrite. To study the signaling pathway associated with p38MAPK during larval settlement, we sought to identify the upstream kinase of p38MAPK. Three MKKs (MKK3, MKK4 and MKK7) and three MAPKs (p38MAPK, ERK and JNK) in A. amphitrite were cloned and recombinantly expressed in E. coli. Through kinase assays, we found that MKK3, but not MKK4 or MKK7, phosphorylated p38MAPK. Furthermore, MKK3 activity was specific to p38MAPK, as it did not phosphorylate ERK or JNK. To further investigate the functional relationship between MKK3 and p38MAPK in vivo, we studied the localization of phospho-MKK3 (pMKK3) and MKK3 by immunostaining. Consistent with the patterns of p38MAPK and phospho-p38MAPK (pp38MAPK), pMKK3 and MKK3 mainly localized to the antennules of the cyprids. Western blot analysis revealed that pMKK3 levels, like pp38MAPK levels, were elevated at cyprid stage, compared to nauplii and juvenile stages. Moreover, pMKK3 levels increased after treatment with adult barnacle crude extracts, suggesting that MKK3 might mediate the stimulatory effects of adult barnacle extracts on the p38MAPK pathway. PMID:23922727

  1. Tetraspanin CD9 regulates osteoclastogenesis via regulation of p44/42 MAPK activity

    SciTech Connect

    Yi, TacGhee; Kim, Hye-Jin; Cho, Je-Yoel; Woo, Kyung Mi; Ryoo, Hyun-Mo; Kim, Gwan-Shik; Baek, Jeong-Hwa . E-mail: baekjh@snu.ac.kr

    2006-08-18

    Tetraspanin CD9 has been shown to regulate cell-cell fusion in sperm-egg fusion and myotube formation. However, the role of CD9 in osteoclast, another multinucleated cell type, is not still clear. Therefore, we investigated the role of CD9 in osteoclast differentiation. CD9 was expressed in osteoclast lineage cells and its expression level increased during the progression of RANKL-induced osteoclastogenesis. KMC8, a neutralizing antibody specific to CD9, significantly suppressed RANKL-induced multinucleated osteoclast formation and the mRNA expression of osteoclast differentiation marker genes. To define CD9-regulated osteoclastogenic signaling pathway, MAPK pathways were examined. KMC8 induced long-term phosphorylation of p44/42 MAPK, but not of p38 MAPK. Constitutive activation of p44/42 MAPK by overexpressing constitutive-active mutant of MEK1 almost completely blocked osteoclast differentiation. Taken together, these results suggest that CD9 expressed on osteoclast lineage cells might positively regulate osteoclastogenesis via the regulation of p44/42 MAPK activity.

  2. PAK1 is a breast cancer oncogene that coordinately activates MAPK and MET signaling

    PubMed Central

    Shrestha, Yashaswi; Schafer, Eric J.; Boehm, Jesse S.; Thomas, Sapana R.; He, Frank; Du, Jinyan; Wang, Shumei; Barretina, Jordi; Weir, Barbara A.; Zhao, Jean J.; Polyak, Kornelia; Golub, Todd R.; Beroukhim, Rameen; Hahn, William C.

    2011-01-01

    Activating mutations in the RAS family or BRAF frequently occur in many types of human cancers but are rarely detected in breast tumors. However, activation of the RAS-RAF-MEK-ERK Mitogen-Activated Protein Kinase (MAPK) pathway is commonly observed in human breast cancers, suggesting that other genetic alterations lead to activation of this signaling pathway. To identify breast cancer oncogenes that activate the MAPK pathway, we screened a library of human kinases for their ability to induce anchorage-independent growth in a derivative of immortalized human mammary epithelial cells (HMLE). We identified PAK1 as a kinase that permitted HMLE cells to form anchorage-independent colonies. PAK1 is amplified in several human cancer types, including 33% of breast tumor samples and cancer cell lines. The kinase activity of PAK1 is necessary for PAK1-induced transformation. Moreover, we show that PAK1 simultaneously activates MAPK and MET signaling; the latter via inhibition of Merlin. Disruption of these activities inhibits PAK1-driven anchorage-independent growth. These observations establish PAK1 amplification as an alternative mechanism for MAPK activation in human breast cancer and credential PAK1 as a breast cancer oncogene that coordinately regulates multiple signaling pathways, the cooperation of which leads to malignant transformation. PMID:22105362

  3. PDGF-BB-mediated activation of p42(MAPK) is independent of PDGF beta-receptor tyrosine phosphorylation.

    PubMed

    Cartel, N J; Liu, J; Wang, J; Post, M

    2001-10-01

    Herein, we investigated the activity of mitogen-activated protein kinase (MAPK), a key component of downstream signaling events, which is activated subsequent to platelet-derived growth factor (PDGF)-BB stimulation. Specifically, p42(MAPK) activity peaked 60 min after addition of PDGF-BB, declined thereafter, and was determined not to be a direct or necessary component of glycosaminoglycan (GAG) synthesis. PDGF-BB also activated MAPK kinase 2 (MAPKK2) but had no effect on MAPKK1 and Raf-1 activity. Chemical inhibition of Janus kinase, phosphatidylinositol 3-kinase, Src kinase, or tyrosine phosphorylation inhibition of the PDGF beta-receptor (PDGFR-beta) did not abrogate PDGF-BB-induced p42(MAPK) activation or its threonine or tyrosine phosphorylation. A dominant negative cytoplasmic receptor for hyaluronan-mediated motility variant 4 (RHAMMv4), a regulator of MAPKK-MAPK interaction and activation, did not inhibit PDGF-BB-induced p42(MAPK) activation nor did a construct expressing PDGFR-beta with cytoplasmic tyrosines mutated to phenylalanine. However, overexpression of a dominant negative PDGFR-beta lacking the cytoplasmic signaling domain abrogated p42(MAPK) activity. These results suggest that PDGF-BB-mediated activation of p42(MAPK) requires the PDGFR-beta but is independent of its tyrosine phosphorylation. PMID:11557582

  4. Kappa Opioid Receptor-Induced Aversion Requires p38 MAPK Activation in VTA Dopamine Neurons

    PubMed Central

    Ehrich, Jonathan M.; Messinger, Daniel I.; Knakal, Cerise R.; Kuhar, Jamie R.; Schattauer, Selena S.; Bruchas, Michael R.; Zweifel, Larry S.; Kieffer, Brigitte L.; Phillips, Paul E.M.

    2015-01-01

    The endogenous dynorphin-κ opioid receptor (KOR) system encodes the dysphoric component of the stress response and controls the risk of depression-like and addiction behaviors; however, the molecular and neural circuit mechanisms are not understood. In this study, we report that KOR activation of p38α MAPK in ventral tegmental (VTA) dopaminergic neurons was required for conditioned place aversion (CPA) in mice. Conditional genetic deletion of floxed KOR or floxed p38α MAPK by Cre recombinase expression in dopaminergic neurons blocked place aversion to the KOR agonist U50,488. Selective viral rescue by wild-type KOR expression in dopaminergic neurons of KOR−/− mice restored U50,488-CPA, whereas expression of a mutated form of KOR that could not initiate p38α MAPK activation did not. Surprisingly, while p38α MAPK inactivation blocked U50,488-CPA, p38α MAPK was not required for KOR inhibition of evoked dopamine release measured by fast scan cyclic voltammetry in the nucleus accumbens. In contrast, KOR activation acutely inhibited VTA dopaminergic neuron firing, and repeated exposure attenuated the opioid response. This adaptation to repeated exposure was blocked by conditional deletion of p38α MAPK, which also blocked KOR-induced tyrosine phosphorylation of the inwardly rectifying potassium channel (GIRK) subunit Kir3.1 in VTA dopaminergic neurons. Consistent with the reduced response, GIRK phosphorylation at this amino terminal tyrosine residue (Y12) enhances channel deactivation. Thus, contrary to prevailing expectations, these results suggest that κ opioid-induced aversion requires regulation of VTA dopaminergic neuron somatic excitability through a p38α MAPK effect on GIRK deactivation kinetics rather than by presynaptically inhibiting dopamine release. SIGNIFICANCE STATEMENT Kappa opioid receptor (KOR) agonists have the potential to be effective, nonaddictive analgesics, but their therapeutic utility is greatly limited by adverse effects on mood

  5. The Mitogen-Activated Protein Kinase (MAPK) Signaling Pathway as a Discovery Target in Stroke.

    PubMed

    Sun, Jing; Nan, Guangxian

    2016-05-01

    Protein kinases are critical modulators of a variety of intracellular and extracellular signal transduction pathways, and abnormal phosphorylation events can contribute to disease progression in a variety of diseases. As a result, protein kinases have emerged as important new drug targets for small molecule therapeutics. The mitogen-activated protein kinase (MAPK) signaling pathway transmits signals from the cell membrane to the nucleus in response to a variety of different stimuli. Because this pathway controls a broad spectrum of cellular processes, including growth, inflammation, and stress responses, it is accepted as a therapeutic target for cancer and peripheral inflammatory disorders. There is also increasing evidence that MAPK is an important regulator of ischemic and hemorrhagic cerebral vascular disease, raising the possibility that it might be a drug discovery target for stroke. In this review, we discuss the MAPK signaling pathway in association with its activation in stroke-induced brain injury. PMID:26842916

  6. S100B/RAGE-dependent activation of microglia via NF-kappaB and AP-1 Co-regulation of COX-2 expression by S100B, IL-1beta and TNF-alpha.

    PubMed

    Bianchi, Roberta; Giambanco, Ileana; Donato, Rosario

    2010-04-01

    Extracellular S100B is known to affect astrocytic, neuronal and microglial activities, with different effects depending on its concentration. Whereas at relatively low concentrations S100B exerts trophic effects on neurons and astrocytes, at relatively high concentrations the protein causes neuronal apoptosis and activates astrocytes and microglia, thus potentially representing an endogenous factor implicated in neuroinflammation. We have reported that RAGE ligation by S100B in BV-2 microglia results in the upregulation of expression of the pro-inflammatory cyclo-oxygenase 2 (COX-2) via parallel Ras-Cdc42-Rac1-dependent activation of c-Jun NH(2) terminal protein kinase (JNK) and Ras-Rac1-dependent stimulation of NF-kappaB transcriptional activity. We show here that: (1) S100B also stimulates AP-1 transcriptional activity in microglia via RAGE-dependent activation of JNK; (2) S100B upregulates IL-1beta and TNF-alpha expression in microglia via RAGE engagement; and (3) S100B/RAGE-induced upregulation of COX-2, IL-1beta and TNF-alpha expression requires the concurrent activation of NF-kappaB and AP-1. We also show that S100B synergizes with IL-1beta and TNF-alpha to upregulate on COX-2 expression in microglia. Given the crucial roles of COX-2, IL-1beta and TNF-alpha in the inflammatory response, we propose that, by engaging RAGE, S100B might play an important role in microglia activation in the course of brain damage. PMID:18599158

  7. 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

  8. EPAS1 trans-activation during hypoxia requires p42/p44 MAPK.

    PubMed

    Conrad, P W; Freeman, T L; Beitner-Johnson, D; Millhorn, D E

    1999-11-19

    Hypoxia is a common environmental stress that regulates gene expression and cell function. A number of hypoxia-regulated transcription factors have been identified and have been shown to play critical roles in mediating cellular responses to hypoxia. One of these is the endothelial PAS-domain protein 1 (EPAS1/HIF2-alpha/HLF/HRF). This protein is 48% homologous to hypoxia-inducible factor 1-alpha (HIF1-alpha). To date, virtually nothing is known about the signaling pathways that lead to either EPAS1 or HIF1-alpha activation. Here we show that EPAS1 is phosphorylated when PC12 cells are exposed to hypoxia and that p42/p44 MAPK is a critical mediator of EPAS1 activation. Pretreatment of PC12 cells with the MEK inhibitor, PD98059, completely blocked hypoxia-induced trans-activation of a hypoxia response element (HRE) reporter gene by transfected EPAS1. Likewise, expression of a constitutively active MEK1 mimicked the effects of hypoxia on HRE reporter gene expression. However, pretreatment with PD98059 had no effect on EPAS1 phosphorylation during hypoxia, suggesting that MAPK targets other proteins that are critical for the trans-activation of EPAS1. We further show that hypoxia-induced trans-activation of EPAS1 is independent of Ras. Finally, pretreatment with calmodulin antagonists nearly completely blocked both the hypoxia-induced phosphorylation of MAPK and the EPAS1 trans-activation of HRE-Luc. These results demonstrate that the MAPK pathway is a critical mediator of EPAS1 activation and that activation of MAPK and EPAS1 occurs through a calmodulin-sensitive pathway and not through the GTPase, Ras. These results are the first to identify a specific signaling pathway involved in EPAS1 activation. PMID:10559262

  9. Pheromone-induced morphogenesis improves osmoadaptation capacity by activating the HOG MAPK pathway.

    PubMed

    Baltanás, Rodrigo; Bush, Alan; Couto, Alicia; Durrieu, Lucía; Hohmann, Stefan; Colman-Lerner, Alejandro

    2013-04-23

    Environmental and internal conditions expose cells to a multiplicity of stimuli whose consequences are difficult to predict. We investigate the response to mating pheromone of yeast cells adapted to high osmolarity. Events downstream of pheromone binding involve two mitogen-activated protein kinase (MAPK) cascades: the pheromone response (PR) and the cell wall integrity (CWI) response. Although the PR MAPK pathway shares components with a third MAPK pathway, the high osmolarity (HOG) response, each one is normally only activated by its cognate stimulus, a phenomenon called insulation. We found that in cells adapted to high osmolarity, PR activated the HOG pathway in a pheromone- and osmolarity-dependent manner. Activation of HOG by the PR was not due to loss of insulation, but rather a response to a reduction in internal osmolarity, which resulted from an increase in glycerol release caused by the PR. By analyzing single-cell time courses, we found that stimulation of HOG occurred in discrete bursts that coincided with the "shmooing" morphogenetic process. Activation required the polarisome, the CWI MAPK Slt2, and the aquaglyceroporin Fps1. HOG activation resulted in high glycerol turnover, which improved adaptability to rapid changes in osmolarity. Our work shows how a differentiation signal can recruit a second, unrelated sensory pathway to fine-tune yeast response in a complex environment. PMID:23612707

  10. Pheromone-Induced Morphogenesis Improves Osmoadaptation Capacity by Activating the HOG MAPK Pathway**

    PubMed Central

    Baltanás, Rodrigo; Bush, Alan; Couto, Alicia; Durrieu, Lucía; Hohmann, Stefan; Colman-Lerner, Alejandro

    2013-01-01

    Environmental and internal conditions expose cells to a multiplicity of stimuli whose consequences are difficult to predict. Here, we investigate the response to mating pheromone of yeast cells adapted to high osmolarity. Events downstream of pheromone binding involve two mitogen-activated protein kinase (MAPK) cascades: the pheromone response (PR) and the cell-wall integrity response (CWI). Although these MAPK pathways share components with each and a third MAPK pathway, the high osmolarity response (HOG), they are normally only activated by distinct stimuli, a phenomenon called insulation. We found that in cells adapted to high osmolarity, PR activated the HOG pathway in a pheromone- and osmolarity- dependent manner. Activation of HOG by the PR was not due to loss of insulation, but rather a response to a reduction in internal osmolarity, which resulted from an increase in glycerol release caused by the PR. By analyzing single-cell time courses, we found that stimulation of HOG occurred in discrete bursts that coincided with the “shmooing” morphogenetic process. Activation required the polarisome, the cell wall integrity MAPK Slt2, and the aquaglyceroporin Fps1. HOG activation resulted in high glycerol turnover that improved adaptability to rapid changes in osmolarity. Our work shows how a differentiation signal can recruit a second, unrelated sensory pathway to enable responses to yeast to multiple stimuli. PMID:23612707

  11. Cooperativity between MAPK and PI3K signaling activation is required for glioblastoma pathogenesis

    PubMed Central

    Vitucci, Mark; Karpinich, Natalie O.; Bash, Ryan E.; Werneke, Andrea M.; Schmid, Ralf S.; White, Kristen K.; McNeill, Robert S.; Huff, Byron; Wang, Sophie; Van Dyke, Terry; Miller, C. Ryan

    2013-01-01

    Background Glioblastoma (GBM) genomes feature recurrent genetic alterations that dysregulate core intracellular signaling pathways, including the G1/S cell cycle checkpoint and the MAPK and PI3K effector arms of receptor tyrosine kinase (RTK) signaling. Elucidation of the phenotypic consequences of activated RTK effectors is required for the design of effective therapeutic and diagnostic strategies. Methods Genetically defined, G1/S checkpoint-defective cortical murine astrocytes with constitutively active Kras and/or Pten deletion mutations were used to systematically investigate the individual and combined roles of these 2 RTK signaling effectors in phenotypic hallmarks of glioblastoma pathogenesis, including growth, migration, and invasion in vitro. A novel syngeneic orthotopic allograft model system was used to examine in vivo tumorigenesis. Results Constitutively active Kras and/or Pten deletion mutations activated both MAPK and PI3K signaling. Their combination led to maximal growth, migration, and invasion of G1/S-defective astrocytes in vitro and produced progenitor-like transcriptomal profiles that mimic human proneural GBM. Activation of both RTK effector arms was required for in vivo tumorigenesis and produced highly invasive, proneural-like GBM. Conclusions These results suggest that cortical astrocytes can be transformed into GBM and that combined dysregulation of MAPK and PI3K signaling revert G1/S-defective astrocytes to a primitive gene expression state. This genetically-defined, immunocompetent model of proneural GBM will be useful for preclinical development of MAPK/PI3K-targeted, subtype-specific therapies. PMID:23814263

  12. FGFR2c-mediated ERK-MAPK activity regulates coronal suture development.

    PubMed

    Pfaff, Miles J; Xue, Ke; Li, Li; Horowitz, Mark C; Steinbacher, Derek M; Eswarakumar, Jacob V P

    2016-07-15

    Fibroblast growth factor receptor 2 (FGFR2) signaling is critical for proper craniofacial development. A gain-of-function mutation in the 2c splice variant of the receptor's gene is associated with Crouzon syndrome, which is characterized by craniosynostosis, the premature fusion of one or more of the cranial vault sutures, leading to craniofacial maldevelopment. Insight into the molecular mechanism of craniosynostosis has identified the ERK-MAPK signaling cascade as a critical regulator of suture patency. The aim of this study is to investigate the role of FGFR2c-induced ERK-MAPK activation in the regulation of coronal suture development. Loss-of-function and gain-of-function Fgfr2c mutant mice have overlapping phenotypes, including coronal synostosis and craniofacial dysmorphia. In vivo analysis of coronal sutures in loss-of-function and gain-of-function models demonstrated fundamentally different pathogenesis underlying coronal suture synostosis. Calvarial osteoblasts from gain-of-function mice demonstrated enhanced osteoblastic function and maturation with concomitant increase in ERK-MAPK activation. In vitro inhibition with the ERK protein inhibitor U0126 mitigated ERK protein activation levels with a concomitant reduction in alkaline phosphatase activity. This study identifies FGFR2c-mediated ERK-MAPK signaling as a key mediator of craniofacial growth and coronal suture development. Furthermore, our results solve the apparent paradox between loss-of-function and gain-of-function FGFR2c mutants with respect to coronal suture synostosis. PMID:27034231

  13. Activation of MAPK Is Necessary for Long-Term Memory Consolidation Following Food-Reward Conditioning

    ERIC Educational Resources Information Center

    Ribeiro, Maria J.; Schofield, Michael G.; Kemenes, Ildiko; O'Shea, Michael; Kemenes, Gyorgy; Benjamin, Paul R.

    2005-01-01

    Although an important role for the mitogen-activated protein kinase (MAPK) has been established for memory consolidation in a variety of learning paradigms, it is not known if this pathway is also involved in appetitive classical conditioning. We address this question by using a single-trial food-reward conditioning paradigm in the freshwater…

  14. Porcine circovirus type 2 activates PI3K/Akt and p38 MAPK pathways to promote interleukin-10 production in macrophages via Cap interaction of gC1qR.

    PubMed

    Du, Qian; Huang, Yong; Wang, Tongtong; Zhang, Xiujuan; Chen, Yu; Cui, Beibei; Li, Delong; Zhao, Xiaomin; Zhang, Wenlong; Chang, Lingling; Tong, Dewen

    2016-04-01

    Porcine circovirus type 2 (PCV2) infection caused PCV2-associated diseases (PCVAD) is one of the major emerging immunosuppression diseases in pig industry. In this study, we investigated how PCV2 inoculation increases interleukin (IL)-10 expression in porcine alveolar macrophages (PAMs). PCV2 inoculation significantly upregulated IL-10 expression compared with PCV1. Upon initial PCV2 inoculation, PI3K/Akt cooperated with NF-κB pathways to promote IL-10 transcription via p50, CREB and Ap1 transcription factors, whereas inhibition of PI3K/Akt activation blocked Ap1 and CREB binding to the il10 promoter, and decreased the binding level of NF-κB1 p50 with il10 promoter, leading to great reduction in early IL-10 transcription. In the later phase of inoculation, PCV2 further activated p38 MAPK and ERK pathways to enhance IL-10 production by promoting Sp1 binding to the il10 promoter. For PCV2-induced IL-10 production in macrophages, PCV2 capsid protein Cap, but not the replicase Rep or ORF3, was the critical component. Cap activated PI3K/Akt, p38 MAPK, and ERK signaling pathways to enhance IL-10 expression. In the whole process, gC1qR mediated PCV2-induced PI3K/Akt and p38 MAPK activation to enhance IL-10 induction by interaction with Cap. Depletion of gC1qR blocked PI3K/Akt and p38 MAPK activation, resulting in significant decrease in IL-10 production in PCV2-inoculated cells. Thus, gC1qR might be a critical functional receptor for PCV2-induced IL-10 production. Taken together, these data demonstrated that Cap protein binding with host gC1qR induction of PI3K/Akt and p38 MAPK signalings activation is a critical process in enhancing PCV2-induced IL-10 production in porcine alveolar macrophages. PMID:26883107

  15. Porcine circovirus type 2 activates PI3K/Akt and p38 MAPK pathways to promote interleukin-10 production in macrophages via Cap interaction of gC1qR

    PubMed Central

    Wang, Tongtong; Zhang, Xiujuan; Chen, Yu; Cui, Beibei; Li, Delong; Zhao, Xiaomin; Zhang, Wenlong; Chang, Lingling; Tong, Dewen

    2016-01-01

    Porcine circovirus type 2 (PCV2) infection caused PCV2-associated diseases (PCVAD) is one of the major emerging immunosuppression diseases in pig industry. In this study, we investigated how PCV2 inoculation increases interleukin (IL)-10 expression in porcine alveolar macrophages (PAMs). PCV2 inoculation significantly upregulated IL-10 expression compared with PCV1. Upon initial PCV2 inoculation, PI3K/Akt cooperated with NF-κB pathways to promote IL-10 transcription via p50, CREB and Ap1 transcription factors, whereas inhibition of PI3K/Akt activation blocked Ap1 and CREB binding to the il10 promoter, and decreased the binding level of NF-κB1 p50 with il10 promoter, leading to great reduction in early IL-10 transcription. In the later phase of inoculation, PCV2 further activated p38 MAPK and ERK pathways to enhance IL-10 production by promoting Sp1 binding to the il10 promoter. For PCV2-induced IL-10 production in macrophages, PCV2 capsid protein Cap, but not the replicase Rep or ORF3, was the critical component. Cap activated PI3K/Akt, p38 MAPK, and ERK signaling pathways to enhance IL-10 expression. In the whole process, gC1qR mediated PCV2-induced PI3K/Akt and p38 MAPK activation to enhance IL-10 induction by interaction with Cap. Depletion of gC1qR blocked PI3K/Akt and p38 MAPK activation, resulting in significant decrease in IL-10 production in PCV2-inoculated cells. Thus, gC1qR might be a critical functional receptor for PCV2-induced IL-10 production. Taken together, these data demonstrated that Cap protein binding with host gC1qR induction of PI3K/Akt and p38 MAPK signalings activation is a critical process in enhancing PCV2-induced IL-10 production in porcine alveolar macrophages. PMID:26883107

  16. The Forkhead Transcription Factor FOXK2 Promotes AP-1-Mediated Transcriptional Regulation

    PubMed Central

    Ji, Zongling; Donaldson, Ian J.; Liu, Jingru; Hayes, Andrew; Zeef, Leo A. H.

    2012-01-01

    The transcriptional control circuitry in eukaryotic cells is complex and is orchestrated by combinatorially acting transcription factors. Forkhead transcription factors often function in concert with heterotypic transcription factors to specify distinct transcriptional programs. Here, we demonstrate that FOXK2 participates in combinatorial transcriptional control with the AP-1 transcription factor. FOXK2 binding regions are widespread throughout the genome and are often coassociated with AP-1 binding motifs. FOXK2 acts to promote AP-1-dependent gene expression changes in response to activation of the AP-1 pathway. In this context, FOXK2 is required for the efficient recruitment of AP-1 to chromatin. Thus, we have uncovered an important new molecular mechanism that controls AP-1-dependent gene expression. PMID:22083952

  17. TRAF6 Autoubiquitination-Independent Activation of the NFκB and MAPK Pathways in Response to IL-1 and RANKL

    PubMed Central

    Walsh, Matthew C.; Kim, Gregory K.; Maurizio, Paul L.; Molnar, Elizabeth E.; Choi, Yongwon

    2008-01-01

    The adapter protein TRAF6 is critical for mediating signal transduction from members of the IL-1R/TLR and TNFR superfamilies. The TRAF6 RING finger domain functions as an ubiquitin E3 ligase capable of generating non-degradative K63-linked ubiquitin chains. It is believed that these chains serve as docking sites for formation of signaling complexes, and that K63-linked autoubiquitination of TRAF6 is essential for formation and activation of a complex involving the kinase TAK1 and its adapters, TAB1 and TAB2. In order to assess independently the E3 ligase and ubiquitin substrate functions of TRAF6, we generated, respectively, RING domain and complete lysine-deficient TRAF6 mutants. We found that while the TRAF6 RING domain is required for activation of TAK1, it is dispensable for interaction between TRAF6 and the TAK1-TAB1-TAB2 complex. Likewise, lysine-deficient TRAF6 was found to interact with the TAK1-TAB1-TAB2 complex, but surprisingly was also found to be fully competent to activate TAK1, as well as NFκB and AP-1 reporters. Furthermore, lysine-deficient TRAF6 rescued IL-1-mediated NFκB and MAPK activation, as well as IL-6 elaboration in retrovirally-rescued TRAF6-deficient fibroblasts. Lysine-deficient TRAF6 also rescued RANKL-mediated NFκB and MAPK activation, and osteoclastogenesis in retrovirally-rescued TRAF6-deficient bone marrow macrophages. While incapable of being ubiquitinated itself, we demonstrate that lysine-deficient TRAF6 remains competent to induce ubiquitination of IKKγ/NEMO. Further, this NEMO modification contributes to TRAF6-mediated activation of NFκB. Collectively, our results suggest that while TRAF6 autoubiquitination may serve as a marker of activation, it is unlikely to underpin RING finger-dependent TRAF6 function. PMID:19112497

  18. Regulation of osteosarcoma cell lung metastasis by the c-Fos/AP-1 target FGFR1.

    PubMed

    Weekes, D; Kashima, T G; Zandueta, C; Perurena, N; Thomas, D P; Sunters, A; Vuillier, C; Bozec, A; El-Emir, E; Miletich, I; Patiño-Garcia, A; Lecanda, F; Grigoriadis, A E

    2016-06-01

    Osteosarcoma is the most common primary malignancy of the skeleton and is prevalent in children and adolescents. Survival rates are poor and have remained stagnant owing to chemoresistance and the high propensity to form lung metastases. In this study, we used in vivo transgenic models of c-fos oncogene-induced osteosarcoma and chondrosarcoma in addition to c-Fos-inducible systems in vitro to investigate downstream signalling pathways that regulate osteosarcoma growth and metastasis. Fgfr1 (fibroblast growth factor receptor 1) was identified as a novel c-Fos/activator protein-1(AP-1)-regulated gene. Induction of c-Fos in vitro in osteoblasts and chondroblasts caused an increase in Fgfr1 RNA and FGFR1 protein expression levels that resulted in increased and sustained activation of mitogen-activated protein kinases (MAPKs), morphological transformation and increased anchorage-independent growth in response to FGF2 ligand treatment. High levels of FGFR1 protein and activated pFRS2α signalling were observed in murine and human osteosarcomas. Pharmacological inhibition of FGFR1 signalling blocked MAPK activation and colony growth of osteosarcoma cells in vitro. Orthotopic injection in vivo of FGFR1-silenced osteosarcoma cells caused a marked twofold to fivefold decrease in spontaneous lung metastases. Similarly, inhibition of FGFR signalling in vivo with the small-molecule inhibitor AZD4547 markedly reduced the number and size of metastatic nodules. Thus deregulated FGFR signalling has an important role in osteoblast transformation and osteosarcoma formation and regulates the development of lung metastases. Our findings support the development of anti-FGFR inhibitors as potential antimetastatic therapy. PMID:26387545

  19. Activation of an AP1-Like Transcription Factor of the Maize Pathogen Cochliobolus heterostrophus in Response to Oxidative Stress and Plant Signals

    SciTech Connect

    Lev, Sophie; hadar, Ruthi; Amedeo, Paolo; Baker, Scott E.; Yoder, Olen; Horwitz, Benjamin A.

    2005-02-01

    Redox sensing is a ubiquitous mechanism regulating cellular activity. Fungal pathogens face reactive oxygen species produced by the host plant's oxidative burst in addition to endogenous reactive oxygen species produced during aerobic metabolism. An array of preformed and induced detoxifying enzymes, including superoxide dismutase, catalases, and peroxidases, could allow fungi to infect plants despite the oxidative burst. We isolated a gene (CHAP1) encoding a redox-regulated transcription factor in Cochliobolus heterostrophus, a fungal pathogen of maize. CHAP1 is a bZIP protein that possesses two cysteine-rich domains structurally and functionally related to Saccharomyces cerevisiae YAP1. Deletion of CHAP1 in C. heterostrophus resulted in decreased resistance to oxidative stress caused by hydrogen peroxide and menadione, but the virulence of chap1 mutants was unaffected. Upon activation by oxidizing agents or plant signals, a green fluorescent protein (GFP)-CHAP1 fusion protein became localized in the nucleus. Expression of genes encoding antioxidant proteins was induced in the wild type but not in chap1 mutants. Activation of CHAP1 occurred from the earliest stage of plant infection, in conidial germ tubes on the leaf surface, and persisted during infection. Late in the course of infection, after extensive necrotic lesions were formed, GFP-CHAP1 redistributed to the cytosol in hyphae growing on the leaf surface. Localization of CHAP1 to the nucleus may, through changes in the redox state of the cell, provide a mechanism linking extracellular cues to transcriptional regulation during the plant-pathogen interaction.

  20. Glabridin inhibits migration and invasion by transcriptional inhibition of matrix metalloproteinase 9 through modulation of NF-κB and AP-1 activity in human liver cancer cells

    PubMed Central

    Hsieh, Ming-Ju; Lin, Chiao-Wen; Yang, Shun-Fa; Chen, Mu-Kuan; Chiou, Hui-Ling

    2014-01-01

    BACKGROUND AND PURPOSE High mortality and morbidity rates for hepatocellular carcinoma in Taiwan primarily result from uncontrolled tumour metastasis. Glabridin, a prenylated isoflavonoid of licorice (Glycyrrhiza glabra) roots, is associated with a wide range of biological properties, such as regulation of energy metabolism, oestrogenic, neuroprotective, anti-osteoporotic and skin whitening. However, the effect of glabridin on the metastasis of tumour cells has not been clarified. EXPERIMENTAL APPROACH A wound healing model and Boyden chamber assays in vitro were used to determine the effects of glabridin on the migration and invasion of human hepatocellular carcinoma (HHC) cells. Western blot analysis, gelatin zymography, real-time PCR and promoter assays were used to evaluate the inhibitory effects of glabridin on matrix metalloproteinase 9 (MMP9) expression in these cells. KEY RESULTS Glabridin significantly inhibited migration/invasion capacities of HCC cells, Huh7 and Sk-Hep-1, cell lines that have low cytotoxicity in vitro, even at high concentrations. Western blot analysis and gelatin zymography showed that glabridin inhibited the expression, activities and protein levels of MMP9 and the phosphorylation of ERK1/2 and JNK1/2. These inhibitory effects were associated with an up-regulation of tissue inhibitor of metalloproteinase-1 and a down-regulation of the transcription factors NF-κB and activator protein 1 signalling pathways. Finally, the administration of glabridin effectively suppressed the tumour formation in the hepatoma xenograft model in vivo. CONCLUSION AND IMPLICATIONS Glabridin inhibited the invasion of human HCC cells and may have potential as a chemopreventive agent against liver cancer metastasis. PMID:24641665

  1. Regulation of osteosarcoma cell lung metastasis by the c-Fos/AP-1 target FGFR1

    PubMed Central

    Weekes, Daniel; Zandueta, Carolina; Perurena, Naiara; Thomas, David P; Sunters, Andrew; Vuillier, Céline; Bozec, Aline; El-Emir, Ethaar; Miletich, Isabelle; Patiño-Garcia, Ana; Lecanda, Fernando; Grigoriadis, Agamemnon E

    2015-01-01

    Osteosarcoma is the most common primary malignancy of the skeleton and is prevalent in children and adolescents. Survival rates are poor and have remained stagnant due to chemoresistance and the high propensity to form lung metastases. In this study, we used in vivo transgenic models of c-fos oncogene-induced osteosarcoma and chondrosarcoma in addition to c-Fos-inducible systems in vitro to investigate downstream signaling pathways that regulate osteosarcoma growth and metastasis. Fgfr1 was identified as a novel c-Fos/AP-1 regulated gene. Induction of c-Fos in vitro in osteoblasts and chondroblasts caused an increase in Fgfr1 RNA and FGFR1 protein expression levels that resulted in increased and sustained activation of MAPKs, morphological transformation and increased anchorage-independent growth in response to FGF2 ligand treatment. High levels of FGFR1 protein and activated pFRS2α signalling were observed in murine and human osteosarcomas. Pharmacological inhibition of FGFR1 signalling blocked MAPK activation and colony growth of osteosarcoma cells in vitro. Orthotopic injection in vivo of FGFR1 silenced osteosarcoma cells caused a marked 2- to 5-fold decrease in spontaneous lung metastases. Similarly, inhibition of FGFR signalling in vivo with the small molecule inhibitor AZD4547 markedly reduced the number and size of metastatic nodules. Thus, deregulated FGFR signalling plays an important role in osteoblast transformation and osteosarcoma formation and regulates the development of lung metastases. Our findings support the development of anti-FGFR inhibitors as potential antimetastatic therapy. PMID:26387545

  2. Brominated Flame Retardants, Tetrabromobisphenol A and Hexabromocyclododecane, Activate Mitogen-Activated Protein Kinases (MAPKs) in Human Natural Killer Cells

    PubMed Central

    Cato, Anita; Celada, Lindsay; Kibakaya, Esther Caroline; Simmons, Nadia; Whalen, Margaret M.

    2014-01-01

    NK cells provide a vital surveillance against virally infected cells, tumor cells, and antibody-coated cells through the release of cytolytic mediators and gamma interferon (IFN-γ). Hexabromocyclododecane (HBCD) is a brominated flame retardant used primarily in expanded (EPS) and extruded (XPS) polystyrene foams for thermal insulation in the building and construction industry. Tetrabromobisphenol A (TBBPA) is used both as a reactive and an additive flame retardant in a variety of materials. HBCD and TBBPA contaminate the environment and are found in human blood samples. In previous studies, we have shown that other environmental contaminants, such as the dibutyltin (DBT) and tributyltin (TBT), decrease NK lytic function by activating mitogen-activated protein kinases (MAPKs) in the NK cells. HBCD and TBBPA also interfere with NK cell(s) lytic function. The current study evaluates whether HBCD and/or TBBPA have the capacity to activate MAPKs and MAPK kinases (MAP2Ks). The effects of concentrations of HBCD and TBBPA that inhibited lytic function on the phosphorylation state and total levels of the MAPKs (p44/42, p38, and JNK) and the phosphorylation and total levels of the MAP2Ks (MEK1/2 and MKK3/6) were examined. Results indicate that exposure of human NK cells to 10-0.5 µM HBCD or TBBPA activate MAPKs and MAP2Ks. This HBCD and TBBPA-induced activation of MAPKs may leave them unavailable for activation by virally infected or tumor target cells and thus contributes to the observed decreases in lytic function seen in NK cells exposed to HBCD and TBBPA. PMID:25341744

  3. Nodularin induces tumor necrosis factor-alpha and mitogen-activated protein kinases (MAPK) and leads to induction of endoplasmic reticulum stress.

    PubMed

    Meili, Nicole; Christen, Verena; Fent, Karl

    2016-06-01

    Nodularin is produced by the cyanobacterium Nodularia spumigena. It is of concern due to hepatotoxicity in humans and animals. Here we investigated unexplored molecular mechanisms by transcription analysis in human liver cells, focusing on induction of pro-inflammatory cytokines, the tumor necrosis factor α (TNF-α), endoplasmic reticulum (ER) stress and components of the activator protein-1 complex in human hepatoma cells (Huh7) exposed to non-cytotoxic (0.1 and 1μM) and toxic concentrations (5μM) for 24, 48, and 72h. Transcripts of TNF-α and ER stress marker genes were strongly induced at 1 and 5μM at all time-points. TNF-α led to induction of mitogen-activated protein kinases (MAPK), as demonstrated by induction of CJUN and CFOS, which form the AP-1 complex. Human primary liver cells reacted more sensitive than Huh7 cells. They showed higher cytotoxicity and induction of TNF-α and ER stress at 2.5nM, while HepG2 cells were insensitive up to 10μM due to low expression of organic anion transporting polypeptides. Furthermore, nodularin led to induction of TNF-α protein, and CCAAT/enhancer-binding protein-homologous (CHOP) protein. Our data indicate that nodularin induces inflammation and ER stress and leads to activation of MAPK in liver cells. All of these activated pathways, which were analysed here for the first time in detail, may contribute to the hepatotoxic, and tumorigenic action of nodularin. PMID:27061667

  4. Genkwanin Inhibits Proinflammatory Mediators Mainly through the Regulation of miR-101/MKP-1/MAPK Pathway in LPS-Activated Macrophages

    PubMed Central

    Gao, Yuan; Liu, Fen; Fang, Lei; Cai, Runlan; Zong, Chuanjie; Qi, Yun

    2014-01-01

    Genkwanin is one of the major non-glycosylated flavonoids in many herbs with anti-inflammatory activities. Although its anti-inflammatory activity in vivo has been reported, the potential molecular mechanisms remain obscure. In this study, by pharmacological and genetic approaches, we explore the anti-inflammatory effects of genkwanin in LPS-activated RAW264.7 macrophages. Genkwanin potently decreases the proinflammatory mediators, such as iNOS, TNF-α, IL-1β and IL-6, at the transcriptional and translational levels without cytotoxicity, indicating the excellent anti-inflammatory potency of genkwanin in vitro. Mechanism study shows that genkwanin significantly suppresses the p38- and JNK-mediated AP-1 signaling pathway and increases the mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP-1) expression at the posttranscriptional level. We also confirmed that microRNA-101 (miR-101) is a negative regulator of MKP-1 expression. Moreover, regardless of miR-101-deficient cells or miR-101-abundant cells, the suppression effects of genkwanin on supernatant proinflammatory mediators' levels are far less than that in respective negative control cells, suggesting that genkwanin exerts anti-inflammatory effect mainly through reducing miR-101 production. However, genkwanin can't affect the level of phospho-Akt (p-Akt), indicating that the phosphorylation of Akt may be not responsible for the effect of genkwanin on miR-101 production. We conclude that genkwanin exerts its anti-inflammatory effect mainly through the regulation of the miR-101/MKP-1/MAPK pathway. PMID:24800851

  5. Estrogenic effect of procymidone through activation of MAPK in MCF-7 breast carcinoma cell line.

    PubMed

    Radice, Sonia; Chiesara, Enzo; Frigerio, Silvia; Fumagalli, Roberta; Parolaro, Daniela; Rubino, Tiziana; Marabini, Laura

    2006-05-01

    Procymidone modifies sexual differentiation in vitro and induces estrogenic activity in primary cultured rainbow trout hepatocytes, as shown by an increase in the contents of vitellogenin and heat shock proteins. Since this dicarboximide fungicide is found in human tissues, it was considered of interest to investigate its ability to induce endocrine damage in the MCF-7 human cell line. The mechanism of this estrogenic action was also evaluated. Procymidone 100 microM stimulated cell growth from day 3 up to day 12 and raised the level of pS2 on day 3. Although procymidone does not bind the estrogen receptor (ER), the antiestrogen ICI 182780 inhibited its effect on cell growth and pS2 content, suggesting that the ER is involved indirectly in these effects. In exploring the mechanism of ER indirect activation we found that the antibody against c-Neu receptor (9G6) did not modify procymidone's effects on cell growth and pS2 expression. Thus, procymidone does not bind the c-Neu membrane receptor, excluding this indirect ER activation pathway. We also found that procymidone induced mitogen-activated protein kinase (MAPK) at 15 and 30 min, and that PD 98059, a MAPK (Erk1/2) inhibitor, prevented procymidone's effects on cell growth and pS2, indicating that MAPK activation is responsible for procymidone ER activation. The production of reactive oxygen species (ROS) with these times and elimination of the phenomenon by alpha-tocopherol (alpha-T), a ROS scavenger, is proof that oxygen free-radical production is at the basis of the MAPK activation by procymidone. PMID:16310225

  6. Anti-Inflammatory Effect of Mangostenone F in Lipopolysaccharide-Stimulated RAW264.7 Macrophages by Suppressing NF-κB and MAPK Activation.

    PubMed

    Cho, Byoung Ok; Ryu, Hyung Won; So, Yangkang; Lee, Chang Wook; Jin, Chang Hyun; Yook, Hong Sun; Jeong, Yong Wook; Park, Jong Chun; Jeong, Il Yun

    2014-07-01

    Mangostenone F (MF) is a natural xanthone isolated from Garcinia mangostana. However, little is known about the biological activities of MF. This study was designed to investigate the anti-inflammatory effect and underlying molecular mechanisms of MF in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. MF dose-dependently inhibited the production of NO, iNOS, and pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) in LPS-stimulated RAW264.7 macrophages. Moreover, MF decreased the NF-κB luciferase activity and NF-κB DNA binding capacity in LPS-stimulated RAW264.7 macrophages. Furthermore, MF suppressed the NF-κB activation by inhibiting the degradation of IκBα and nuclear translocation of p65 subunit of NF-κB. In addition, MF attenuated the AP-1 luciferase activity and phosphorylation of ERK, JNK, and p38 MAP kinases. Taken together, these results suggest that the anti-inflammatory effect of MF is associated with the suppression of NO production and iNOS expression through the down-regulation of NF-κB activation and MAPK signaling pathway in LPS-stimulated RAW264.7 macrophages. PMID:25143806

  7. N-hydroxycinnamide derivatives of osthole ameliorate hyperglycemia through activation of AMPK and p38 MAPK.

    PubMed

    Lee, Wei-Hwa; Wu, Hsueh-Hsia; Huang, Wei-Jan; Li, Yi-Ning; Lin, Ren-Jye; Lin, Shyr-Yi; Liang, Yu-Chih

    2015-01-01

    Our previous studies found that osthole markedly reduced blood glucose levels in both db/db and ob/ob mice. To improve the antidiabetic activity of osthole, a series of N-hydroxycinnamide derivatives of osthole were synthesized, and their hypoglycemia activities were examined in vitro and in vivo. Both N-hydroxycinnamide derivatives of osthole, OHC-4p and OHC-2m, had the greatest potential for activating AMPK and increasing glucose uptake by L6 skeletal muscle cells. In addition, OHC-4p and OHC-2m time- and dose-dependently increased phosphorylation levels of AMPK and p38 MAPK. The AMPK inhibitor, compound C, and the p38 MAPK inhibitor, SB203580, significantly reversed activation of AMPK and p38 MAPK, respectively, in OHC-4p- and OHC-2m-treated cells. Compound C and SB203580 also inhibited glucose uptake induced by OHC-4p and OHC-2m. Next, we found that OHC-4p and OHC-2m significantly increased glucose transporter 4 (GLUT4) translocation to plasma membranes and counteracted hyperglycemia in mice with streptozotocin-induced diabetes. These results suggest that activation of AMPK and p38 MAPK by OHC-4p and OHC-2m is associated with increased glucose uptake and GLUT4 translocation and subsequently led to amelioration of hyperglycemia. Therefore, OHC-4p and OHC-2m might have potential as antidiabetic agents for treating type 2 diabetes. Our previous studies found that osthole markedly reduced blood glucose levels in both db/db and ob/ob mice. To improve the antidiabetic activity of osthole, a series of N-hydroxycinnamide derivatives of osthole were synthesized, and their hypoglycemia activities were examined in vitro and in vivo. Both N-hydroxycinnamide derivatives of osthole, OHC-4p and OHC-2m, had the greatest potential for activating AMPK and increasing glucose uptake by L6 skeletal muscle cells. In addition, OHC-4p and OHC-2m time- and dose-dependently increased phosphorylation levels of AMPK and p38 MAPK. The AMPK inhibitor, compound C, and the p38 MAPK inhibitor

  8. Premature senescence involving p53 and p16 is activated in response to constitutive MEK/MAPK mitogenic signaling

    PubMed Central

    Lin, Athena W.; Barradas, Marta; Stone, James C.; van Aelst, Linda; Serrano, Manuel; Lowe, Scott W.

    1998-01-01

    Oncogenic Ras transforms immortal rodent cells to a tumorigenic state, in part, by constitutively transmitting mitogenic signals through the mitogen-activated protein kinase (MAPK) cascade. In primary cells, Ras is initially mitogenic but eventually induces premature senescence involving the p53 and p16INK4a tumor suppressors. Constitutive activation of MEK (a component of the MAPK cascade) induces both p53 and p16, and is required for Ras-induced senescence of normal human fibroblasts. Furthermore, activated MEK permanently arrests primary murine fibroblasts but forces uncontrolled mitogenesis and transformation in cells lacking either p53 or INK4a. The precisely opposite response of normal and immortalized cells to constitutive activation of the MAPK cascade implies that premature senescence acts as a fail-safe mechanism to limit the transforming potential of excessive Ras mitogenic signaling. Consequently, constitutive MAPK signaling activates p53 and p16 as tumor suppressors. PMID:9765203

  9. Atractylodin Inhibits Interleukin-6 by Blocking NPM-ALK Activation and MAPKs in HMC-1.

    PubMed

    Chae, Hee-Sung; Kim, Young-Mi; Chin, Young-Won

    2016-01-01

    Atractylodin is one of the major constituents of the rhizome of Atractylodes lancea, which is widely used in Korean traditional medicine as a remedy for the treatment of gastritis and gastric ulcers. Despite of a major constituent of widely used botanical to treat inflammatory responses little is known about anti-inflammatory effect of atractylodin in the human mast cell (HMC-1). Hence, we evaluated the effect of atractylodin on the release of IL-6, the involvement of nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) and mitogen-activated protein kinases (MAPKs) in phorbol-12-myristate-13-acetate and A23187-induced HMC-1. In addition, Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), phospholipase C (PLC) gamma 1, and AKT phosphorylation relevant to NPM-ALK signal pathway were assessed. IL-6 levels in the HMC-1 stimulated by phorbol-12-myristate-13-acetate and A23187 were apparently decreased by the treatment of atractylodin. Concurrently, atractylodin not only inhibited the phosphorylation of NPM-ALK, but also suppressed the phosphorylation of JAK2, STAT3, PLC gamma 1, and AKT. Furthermore, the activated mitogen-activated protein kinases (MAPKs) by phorbol-12-myristate-13-acetate and A23187 were inhibited by atractylodin. These results suggested that atractylodin might have a potential regulatory effect on inflammatory mediator expression through blockade of both the phosphorylation of MAPKs and the NPM-ALK signaling pathway. PMID:27598116

  10. 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. PMID:27471255

  11. Dioscorea nipponica Makino inhibits migration and invasion of human oral cancer HSC-3 cells by transcriptional inhibition of matrix metalloproteinase-2 through modulation of CREB and AP-1 activity.

    PubMed

    Chien, Ming-Hsien; Ying, Tsung-Ho; Hsieh, Yih-Shou; Chang, Yu-Chao; Yeh, Chia-Ming; Ko, Jiunn-Liang; Lee, Wen-Sen; Chang, Jer-Hua; Yang, Shun-Fa

    2012-03-01

    Oral cancer mortality has increased during the last decade due to the difficulties in treating related metastasis. Dioscorea nipponica Makino, a popular folk medicine, exerts anti-obesity and anti-inflammation properties. However, the effect of this folk medicine on metastasis of oral cancer has yet to be fully elucidated. The present study demonstrates that D. nipponica extracts (DNE), at a range of concentrations (0-50 μg/mL), concentration-dependently inhibited migration/invasion capacities of human oral cancer cells, HSC-3, without cytotoxic effects. The anti-migration effect of DNE was also observed in two other OSCC cell lines, Ca9-22 and Cal-27. Zymography, real time PCR, and Western blotting analyses revealed that DNE inhibited matrix metalloproteinase-2 (MMP-2) enzyme activity, and RNA and protein expression. The inhibitory effects of DNE on MMP-2 proceeded by up-regulating tissue inhibitor of metalloproteinase-2 (TIMP-2), as well as suppressing nuclear translocation and DNA binding activity of cAMP response element-binding (CREB) and activating protein-1 (AP-1) on the MMP-2 promoter in HSC-3 cells. In conclusion, DNE inhibited the invasion of oral cancer cells and may have potential use as a chemopreventive agent against oral cancer metastasis. PMID:22210353

  12. Ganoderma lucidum polysaccharide exerts anti-tumor activity via MAPK pathways in HL-60 acute leukemia cells.

    PubMed

    Yang, Guohua; Yang, Lei; Zhuang, Yun; Qian, Xifeng; Shen, Yunfeng

    2016-01-01

    In this study, we investigated the anti-tumor activity both in vitro and in vivo of a polysaccharide obtained from Ganoderma lucidum on HL-60 acute myeloid leukemia cells, and focused on its targeting effect on mitogen-activated protein kinase (MAPK) pathways. It was found by the methods such as western blot and flow cytometry (FCM), that G. lucidum polysaccharide (GLP) blocked the extracellular signal-regulated kinase/MAPK signaling pathway, simultaneously activated p38 and JNK MAPK pathways, and therefore regulated their downstream genes and proteins, including p53, c-myc, c-fos, c-jun, Bcl-2, Bax, cleaved caspase-3 and cyclin D1. As a result, cycle arrest and apoptosis of HL-60 cells were induced. Therefore, GLP exerted anti-tumor activity via MAPK pathways in HL-60 acute leukemia cells. PMID:25327706

  13. WNT3 Inhibits Cerebellar Granule Neuron Progenitor Proliferation and Medulloblastoma Formation via MAPK Activation

    PubMed Central

    Ayrault, Olivier; Kim, Jee Hae; Zhu, Xiaodong; Murphy, David A.; Van Aelst, Linda; Roussel, Martine F.; Hatten, Mary E.

    2013-01-01

    During normal cerebellar development, the remarkable expansion of granule cell progenitors (GCPs) generates a population of granule neurons that outnumbers the total neuronal population of the cerebral cortex, and provides a model for identifying signaling pathways that may be defective in medulloblastoma. While many studies focus on identifying pathways that promote growth of GCPs, a critical unanswered question concerns the identification of signaling pathways that block mitogenic stimulation and induce early steps in differentiation. Here we identify WNT3 as a novel suppressor of GCP proliferation during cerebellar development and an inhibitor of medulloblastoma growth in mice. WNT3, produced in early postnatal cerebellum, inhibits GCP proliferation by down-regulating pro-proliferative target genes of the mitogen Sonic Hedgehog (SHH) and the bHLH transcription factor Atoh1. WNT3 suppresses GCP growth through a non-canonical Wnt signaling pathway, activating prototypic mitogen-activated protein kinases (MAPKs), the Ras-dependent extracellular-signal-regulated kinases 1/2 (ERK1/2) and ERK5, instead of the classical β-catenin pathway. Inhibition of MAPK activity using a MAPK kinase (MEK) inhibitor reversed the inhibitory effect of WNT3 on GCP proliferation. Importantly, WNT3 inhibits proliferation of medulloblastoma tumor growth in mouse models by a similar mechanism. Thus, the present study suggests a novel role for WNT3 as a regulator of neurogenesis and repressor of neural tumors. PMID:24303070

  14. Basal protein phosphatase 2A activity restrains cytokine expression: role for MAPKs and tristetraprolin.

    PubMed

    Rahman, Md Mostafizur; Rumzhum, Nowshin N; Morris, Jonathan C; Clark, Andrew R; Verrills, Nicole M; Ammit, Alaina J

    2015-01-01

    PP2A is a master controller of multiple inflammatory signaling pathways. It is a target in asthma; however the molecular mechanisms by which PP2A controls inflammation warrant further investigation. In A549 lung epithelial cells in vitro we show that inhibition of basal PP2A activity by okadaic acid (OA) releases restraint on MAPKs and thereby increases MAPK-mediated pro-asthmatic cytokines, including IL-6 and IL-8. Notably, PP2A inhibition also impacts on the anti-inflammatory protein - tristetraprolin (TTP), a destabilizing RNA binding protein regulated at multiple levels by p38 MAPK. Although PP2A inhibition increases TTP mRNA expression, resultant TTP protein builds up in the hyperphosphorylated inactive form. Thus, when PP2A activity is repressed, pro-inflammatory cytokines increase and anti-inflammatory proteins are rendered inactive. Importantly, these effects can be reversed by the PP2A activators FTY720 and AAL(s), or more specifically by overexpression of the PP2A catalytic subunit (PP2A-C). Moreover, PP2A plays an important role in cytokine expression in cells stimulated with TNFα; as inhibition of PP2A with OA or PP2A-C siRNA results in significant increases in cytokine production. Collectively, these data reveal the molecular mechanisms of PP2A regulation and highlight the potential of boosting the power of endogenous phosphatases as novel anti-inflammatory strategies to combat asthmatic inflammation. PMID:25985190

  15. A novel p38 mitogen activated protein kinase (MAPK) specific inhibitor suppresses respiratory syncytial virus and influenza A virus replication by inhibiting virus-induced p38 MAPK activation.

    PubMed

    Choi, Myung-Soo; Heo, Jinyuk; Yi, Chae-Min; Ban, Junsu; Lee, Noh-Jin; Lee, Na-Rae; Kim, Sang Won; Kim, Nam-Jung; Inn, Kyung-Soo

    2016-08-26

    Respiratory syncytial virus (RSV) and influenza A virus are leading causes of acute lower respiratory infectious disease. Respiratory diseases caused by RSV and influenza A virus result in serious economic burden and life-threatening disease for immunocompromised people. With the revelation that p38 mitogen-activated protein kinase (MAPK) activity in host cells is crucial for infection and replication of RSV and influenza A virus, inhibition of p38 MAPK activity has been suggested as a potential antiviral therapeutic strategy. However, the low selectivity and high toxicity of the p38 MAPK inhibitors necessitate the development of better inhibitors. Herein, we report the synthesis of a novel p38 MAPK inhibitor, NJK14047, with high kinase selectivity. In this work, it was demonstrated that NJK14047 inhibits RSV- and influenza A-mediated p38 MAPK activation in epithelial cells. Subsequently, NJK14047 treatment resulted in decreased viral replication and viral mRNA synthesis. In addition, secretion of interleukin-6 from infected cells was greatly diminished by NJK14047, suggesting that it can ameliorate immunopathological responses to RSV and influenza A. Collectively, the results suggest that NJK14047 has therapeutic potential to treat respiratory viral infection through the suppression of p38 MAPK activation, which is suggested to be an essential step for respiratory virus infection. PMID:27346133

  16. Concurrent BMP7 and FGF9 signalling governs AP-1 function to promote self-renewal of nephron progenitor cells

    PubMed Central

    Muthukrishnan, Sree Deepthi; Yang, Xuehui; Friesel, Robert; Oxburgh, Leif

    2015-01-01

    Self-renewal of nephron progenitor cells (NPCs) is governed by BMP, FGF and WNT signalling. Mechanisms underlying cross-talk between these pathways at the molecular level are largely unknown. Here we delineate the pathway through which the proliferative BMP7 signal is transduced in NPCs in the mouse. BMP7 activates the MAPKs TAK1 and JNK to phosphorylate the transcription factor JUN, which in turn governs transcription of AP-1-element containing G1-phase cell cycle regulators such as Myc and Ccnd1 to promote NPC proliferation. Conditional inactivation of Tak1 or Jun in cap mesenchyme causes identical phenotypes characterized by premature depletion of NPCs. While JUN is regulated by BMP7, we find that its partner FOS is regulated by FGF9. We demonstrate that BMP7 and FGF9 coordinately regulate AP-1 transcription to promote G1-S cell cycle progression and NPC proliferation. Our findings identify a molecular mechanism explaining the important cooperation between two major NPC self-renewal pathways. PMID:26634297

  17. The Mitogen-Activated Protein Kinase (MAPK) Pathway: Role in Immune Evasion by Trypanosomatids

    PubMed Central

    Soares-Silva, Mercedes; Diniz, Flavia F.; Gomes, Gabriela N.; Bahia, Diana

    2016-01-01

    Leishmania spp. and Trypanosoma cruzi are the causative agents of leishmaniasis and Chagas disease, respectively, two neglected tropical diseases that affect about 25 million people worldwide. These parasites belong to the family Trypanosomatidae, and are both obligate intracellular parasites that manipulate host signaling pathways and the innate immune system to establish infection. Mitogen-activated protein kinases (MAPKs) are serine and threonine protein kinases that are highly conserved in eukaryotes, and are involved in signal transduction pathways that modulate physiological and pathophysiological cell responses. This mini-review highlights existing knowledge concerning the mechanisms that Leishmania spp. and T. cruzi have evolved to target the host’s MAPK signaling pathways and highjack the immune response, and, in this manner, promote parasite maintenance in the host. PMID:26941717

  18. The Mitogen-Activated Protein Kinase (MAPK) Pathway: Role in Immune Evasion by Trypanosomatids.

    PubMed

    Soares-Silva, Mercedes; Diniz, Flavia F; Gomes, Gabriela N; Bahia, Diana

    2016-01-01

    Leishmania spp. and Trypanosoma cruzi are the causative agents of leishmaniasis and Chagas disease, respectively, two neglected tropical diseases that affect about 25 million people worldwide. These parasites belong to the family Trypanosomatidae, and are both obligate intracellular parasites that manipulate host signaling pathways and the innate immune system to establish infection. Mitogen-activated protein kinases (MAPKs) are serine and threonine protein kinases that are highly conserved in eukaryotes, and are involved in signal transduction pathways that modulate physiological and pathophysiological cell responses. This mini-review highlights existing knowledge concerning the mechanisms that Leishmania spp. and T. cruzi have evolved to target the host's MAPK signaling pathways and highjack the immune response, and, in this manner, promote parasite maintenance in the host. PMID:26941717

  19. The activation of p38MAPK and JNK pathways in bovine herpesvirus 1 infected MDBK cells.

    PubMed

    Zhu, Liqian; Yuan, Chen; Huang, Liyuan; Ding, Xiuyan; Wang, Jianye; Zhang, Dong; Zhu, Guoqiang

    2016-01-01

    We have shown previously that BHV-1 infection activates Erk1/2 signaling. Here, we show that BHV-1 provoked an early-stage transient and late-stage sustained activation of JNK, p38MAPK and c-Jun signaling in MDBK cells. C-Jun phosphorylation was dependent on JNK. These early events were partially due to the viral entry process. Unexpectedly, reactive oxygen species were not involved in the later activation phase. Interestingly, only activated JNK facilitated the viral multiplication identified through both chemical inhibitor and siRNA. Collectively, this study provides insight into our understanding of early stages of BHV-1 infection. PMID:27590675

  20. Ribosome Synthesis and MAPK Activity Modulate Ionizing Radiation-Induced Germ Cell Apoptosis in Caenorhabditis elegans

    PubMed Central

    Eberhard, Ralf; Stergiou, Lilli; Hofmann, E. Randal; Hofmann, Jen; Haenni, Simon; Teo, Youjin; Furger, André; Hengartner, Michael O.

    2013-01-01

    Synthesis of ribosomal RNA by RNA polymerase I (RNA pol I) is an elemental biological process and is key for cellular homeostasis. In a forward genetic screen in C. elegans designed to identify DNA damage-response factors, we isolated a point mutation of RNA pol I, rpoa-2(op259), that leads to altered rRNA synthesis and a concomitant resistance to ionizing radiation (IR)-induced germ cell apoptosis. This weak apoptotic IR response could be phenocopied when interfering with other factors of ribosome synthesis. Surprisingly, despite their resistance to DNA damage, rpoa-2(op259) mutants present a normal CEP-1/p53 response to IR and increased basal CEP-1 activity under normal growth conditions. In parallel, rpoa-2(op259) leads to reduced Ras/MAPK pathway activity, which is required for germ cell progression and physiological germ cell death. Ras/MAPK gain-of-function conditions could rescue the IR response defect in rpoa-2(op259), pointing to a function for Ras/MAPK in modulating DNA damage-induced apoptosis downstream of CEP-1. Our data demonstrate that a single point mutation in an RNA pol I subunit can interfere with multiple key signalling pathways. Ribosome synthesis and growth-factor signalling are perturbed in many cancer cells; such an interplay between basic cellular processes and signalling might be critical for how tumours evolve or respond to treatment. PMID:24278030

  1. BMP9-Induced Survival Effect in Liver Tumor Cells Requires p38MAPK Activation

    PubMed Central

    García-Álvaro, María; Addante, Annalisa; Roncero, Cesáreo; Fernández, Margarita; Fabregat, Isabel; Sánchez, Aránzazu; Herrera, Blanca

    2015-01-01

    The study of bone morphogenetic proteins (BMPs) role in tumorigenic processes, and specifically in the liver, has gathered importance in the last few years. Previous studies have shown that BMP9 is overexpressed in about 40% of hepatocellular carcinoma (HCC) patients. In vitro data have also shown evidence that BMP9 has a pro-tumorigenic action, not only by inducing epithelial to mesenchymal transition (EMT) and migration, but also by promoting proliferation and survival in liver cancer cells. However, the precise mechanisms driving these effects have not yet been established. In the present work, we deepened our studies into the intracellular mechanisms implicated in the BMP9 proliferative and pro-survival effect on liver tumor cells. In HepG2 cells, BMP9 induces both Smad and non-Smad signaling cascades, specifically PI3K/AKT and p38MAPK. However, only the p38MAPK pathway contributes to the BMP9 growth-promoting effect on these cells. Using genetic and pharmacological approaches, we demonstrate that p38MAPK activation, although dispensable for the BMP9 proliferative activity, is required for the BMP9 protective effect on serum withdrawal-induced apoptosis. These findings contribute to a better understanding of the signaling pathways involved in the BMP9 pro-tumorigenic role in liver tumor cells. PMID:26343646

  2. Involvement of p38 MAPK in the Anticancer Activity of Cultivated Cordyceps militaris.

    PubMed

    Chou, Shang-Min; Lai, Wan-Jung; Hong, Tzuwen; Tsai, Sheng-Hong; Chen, Yen-Hsun; Kao, Cheng-Hsiang; Chu, Richard; Shen, Tang-Long; Li, Tsai-Kun

    2015-01-01

    Cordyceps militaris is a traditional Chinese medicine frequently used for tonic and therapeutic purposes. Reports from our laboratory and others have demonstrated that extracts of the cultivated fruiting bodies of C. militaris (CM) exhibit a potent cytotoxic effect against many cancer cell lines, especially human leukemia cells. Here, we further investigated the underlying mechanism through which CM is cytotoxic to cancer cells. The CM-mediated induction of PARP cleavage and its related DNA damage signal (γH2AX) was diminished by caspase inhibitor I. In contrast, a ROS scavenger failed to prevent CM-mediated leukemia cell death. Moreover, two signaling molecules, AKT and p38 MAPK, were activated during the course of apoptosis induction. Employing MTT analysis, we found that a p38 MAPK inhibitor but not an AKT inhibitor could rescue cells from CM-mediated cell death, as well as inhibit the cleavage of PARP, formation of apoptotic bodies and up-regulation of the γH2AX signal. These results suggest that CM-mediated leukemia cell death occurs through the activation of the p38 MAPK pathway, indicating its potential therapeutic effects against human leukemia. PMID:26205966

  3. Cadmium induces vascular permeability via activation of the p38 MAPK pathway

    SciTech Connect

    Dong, Fengyun; Guo, Fang; Li, Liqun; Guo, Ling; Hou, Yinglong; Hao, Enkui; Yan, Suhua; Allen, Thaddeus D.; Liu, Ju

    2014-07-18

    Highlights: • Low-dose cadmium (Cd) induces vascular hyper-permeability. • p38 MAPK mediates Cd-induced disruption of endothelial cell barrier function. • SB203850 inhibits Cd-induced membrane dissociation of VE-cadherin and β-catenin. • SB203850 reduces Cd-induced expression and secretion of TNF-α. - Abstract: The vasculature of various organs is a targeted by the environmental toxin, cadmium (Cd). However, mechanisms leading to pathological conditions are poorly understood. In the present study, we examined the effect of cadmium chloride (CdCl{sub 2}) on human umbilical vein endothelial cells (HUVECs). At 4 μM, CdCl{sub 2} induced a hyper-permeability defect in HUVECs, but not the inhibition of cell growth up to 24 h. This effect of CdCl{sub 2} was dependent on the activation of the p38 mitogen-activated protein kinase (MAPK) pathway. The p38 MAPK inhibitor SB203850 suppressed the CdCl{sub 2}-induced alteration in trans-endothelial electrical resistance in HUVEC monolayers, a model measurement of vascular endothelial barrier integrity. SB203850 also inhibited the Cd-induced membrane dissociation of vascular endothelial (VE) cadherin and β-catenin, the important components of the adherens junctional complex. In addition, SB203850 reduces the Cd-induced expression and secretion of tumor necrosis factor α (TNF-α). Taken together, our findings suggest that Cd induces vascular hyper-permeability and disruption of endothelial barrier integrity through stimulation of p38 MAPK signaling.

  4. BMP7 retards peripheral myelination by activating p38 MAPK in Schwann cells

    PubMed Central

    Liu, Xiaoyu; Zhao, Yahong; Peng, Su; Zhang, Shuqiang; Wang, Meihong; Chen, Yeyue; Zhang, Shan; Yang, Yumin; Sun, Cheng

    2016-01-01

    Schwann cell (SC) myelination is pivotal for the proper physiological functioning of the nervous system, but the underlying molecular mechanism remains less well understood. Here, we showed that the expression of bone morphogenetic protein 7 (BMP7) inversely correlates with myelin gene expression during peripheral myelination, which suggests that BMP7 is likely a negative regulator for myelin gene expression. Our experiments further showed that the application of BMP7 attenuates the cAMP induced myelin gene expression in SCs. Downstream pathway analysis suggested that both p38 MAPK and SMAD are activated by exogenous BMP7 in SCs. The pharmacological intervention and gene silence studies revealed that p38 MAPK, not SMAD, is responsible for BMP7-mediated suppression of myelin gene expression. In addition, c-Jun, a potential negative regulator for peripheral myelination, was up-regulated by BMP7. In vivo experiments showed that BMP7 treatment greatly impaired peripheral myelination in newborn rats. Together, our results established that BMP7 is a negative regulator for peripheral myelin gene expression and that p38 MAPK/c-Jun axis might be the main downstream target of BMP7 in this process. PMID:27491681

  5. BMP7 retards peripheral myelination by activating p38 MAPK in Schwann cells.

    PubMed

    Liu, Xiaoyu; Zhao, Yahong; Peng, Su; Zhang, Shuqiang; Wang, Meihong; Chen, Yeyue; Zhang, Shan; Yang, Yumin; Sun, Cheng

    2016-01-01

    Schwann cell (SC) myelination is pivotal for the proper physiological functioning of the nervous system, but the underlying molecular mechanism remains less well understood. Here, we showed that the expression of bone morphogenetic protein 7 (BMP7) inversely correlates with myelin gene expression during peripheral myelination, which suggests that BMP7 is likely a negative regulator for myelin gene expression. Our experiments further showed that the application of BMP7 attenuates the cAMP induced myelin gene expression in SCs. Downstream pathway analysis suggested that both p38 MAPK and SMAD are activated by exogenous BMP7 in SCs. The pharmacological intervention and gene silence studies revealed that p38 MAPK, not SMAD, is responsible for BMP7-mediated suppression of myelin gene expression. In addition, c-Jun, a potential negative regulator for peripheral myelination, was up-regulated by BMP7. In vivo experiments showed that BMP7 treatment greatly impaired peripheral myelination in newborn rats. Together, our results established that BMP7 is a negative regulator for peripheral myelin gene expression and that p38 MAPK/c-Jun axis might be the main downstream target of BMP7 in this process. PMID:27491681

  6. OsMAPK6, a mitogen-activated protein kinase, influences rice grain size and biomass production.

    PubMed

    Liu, Shuying; Hua, Lei; Dong, Sujun; Chen, Hongqi; Zhu, Xudong; Jiang, Jun'e; Zhang, Fang; Li, Yunhai; Fang, Xiaohua; Chen, Fan

    2015-11-01

    Grain size is an important agronomic trait in determining grain yield. However, the molecular mechanisms that determine the final grain size are not well understood. Here, we report the functional analysis of a rice (Oryza sativa L.) mutant, dwarf and small grain1 (dsg1), which displays pleiotropic phenotypes, including small grains, dwarfism and erect leaves. Cytological observations revealed that the small grain and dwarfism of dsg1 were mainly caused by the inhibition of cell proliferation. Map-based cloning revealed that DSG1 encoded a mitogen-activated protein kinase (MAPK), OsMAPK6. OsMAPK6 was mainly located in the nucleus and cytoplasm, and was ubiquitously distributed in various organs, predominately in spikelets and spikelet hulls, consistent with its role in grain size and biomass production. As a functional kinase, OsMAPK6 interacts strongly with OsMKK4, indicating that OsMKK4 is likely to be the upstream MAPK kinase of OsMAPK6 in rice. In addition, hormone sensitivity tests indicated that the dsg1 mutant was less sensitive to brassinosteroids (BRs). The endogenous BR levels were reduced in dsg1, and the expression of several BR signaling pathway genes and feedback-inhibited genes was altered in the dsg1 mutant, with or without exogenous BRs, indicating that OsMAPK6 may contribute to influence BR homeostasis and signaling. Thus, OsMAPK6, a MAPK, plays a pivotal role in grain size in rice, via cell proliferation, and BR signaling and homeostasis. PMID:26366992

  7. Voltage-gated Na+ Channel Activity Increases Colon Cancer Transcriptional Activity and Invasion Via Persistent MAPK Signaling

    NASA Astrophysics Data System (ADS)

    House, Carrie D.; Wang, Bi-Dar; Ceniccola, Kristin; Williams, Russell; Simaan, May; Olender, Jacqueline; Patel, Vyomesh; Baptista-Hon, Daniel T.; Annunziata, Christina M.; Silvio Gutkind, J.; Hales, Tim G.; Lee, Norman H.

    2015-06-01

    Functional expression of voltage-gated Na+ channels (VGSCs) has been demonstrated in multiple cancer cell types where channel activity induces invasive activity. The signaling mechanisms by which VGSCs promote oncogenesis remain poorly understood. We explored the signal transduction process critical to VGSC-mediated invasion on the basis of reports linking channel activity to gene expression changes in excitable cells. Coincidentally, many genes transcriptionally regulated by the SCN5A isoform in colon cancer have an over-representation of cis-acting sites for transcription factors phosphorylated by ERK1/2 MAPK. We hypothesized that VGSC activity promotes MAPK activation to induce transcriptional changes in invasion-related genes. Using pharmacological inhibitors/activators and siRNA-mediated gene knockdowns, we correlated channel activity with Rap1-dependent persistent MAPK activation in the SW620 human colon cancer cell line. We further demonstrated that VGSC activity induces downstream changes in invasion-related gene expression via a PKA/ERK/c-JUN/ELK-1/ETS-1 transcriptional pathway. This is the first study illustrating a molecular mechanism linking functional activity of VGSCs to transcriptional activation of invasion-related genes.

  8. Molecular basis for enhancement of the meiotic DMC1 recombinase by RAD51 associated protein 1 (RAD51AP1)

    PubMed Central

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

    2011-01-01

    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 cooperation 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 colocalize with a subset of DMC1 foci in spermatocytes. These results suggest that RAD51AP1 also serves an important role in meiotic homologous recombination. PMID:21307306

  9. Clathrin interactions with C-terminal regions of the yeast AP-1 beta and gamma subunits are important for AP-1 association with clathrin coats.

    PubMed

    Yeung, B G; Payne, G S

    2001-08-01

    Heterotetrameric adaptor (AP) complexes are thought to coordinate cargo recruitment and clathrin assembly during clathrin-coated vesicle biogenesis. We have identified, and characterized the physiological significance of clathrin-binding activities in the two large subunits of the AP-1 complex in Saccharomyces cerevisiae. Using GST-fusion chromatography, two clathrin-binding sites were defined in the beta1 subunit that match consensus clathrin-binding sequences in other mammalian and yeast clathrin-binding proteins. Clathrin interactions were also identified with the C-terminal region of the gamma subunit. When introduced into chromosomal genes, point mutations in the beta1 clathrin-binding motifs, or deletion of the gamma C-terminal region, reduced association of AP-1 with clathrin in coimmunoprecipitation assays. The beta1 mutations or the gamma truncation individually produced minor effects on AP-1 distribution by subcellular fractionation. However, when beta1 and gamma mutations were combined, severe defects were observed in AP-1 association with membranes and incorporation into clathrin-coated vesicles. The combination of subunit mutations accentuated growth and alpha-factor pheromone maturation defects in chc1-ts cells, though not to the extent caused by complete loss of AP-1 activity. Our results suggest that both the beta1 and gamma subunits contribute interactions with clathrin that are important for stable assembly of AP-1 complexes into clathrin coats in vivo. PMID:11489214

  10. Curcumin increases gelatinase activity in human neutrophils by a p38 mitogen-activated protein kinase (MAPK)-independent mechanism.

    PubMed

    Antoine, Francis; Girard, Denis

    2015-01-01

    Curcumin has been found to possess anti-inflammatory activities and neutrophils, key players in inflammation, were previously found to be important targets to curcumin in a few studies. For example, curcumin was found to induce apoptosis in neutrophils by a p38 mitogen-activated protein kinase (MAPK)-dependent mechanism. However, the role of curcumin on the biology of neutrophils is still poorly defined. To study the role of curcumin on neutrophil degranulation and to determine the role of p38 MAPK, human neutrophils were freshly isolated from healthy individuals and incubated in vitro with curcumin. Degranulation was studied at three levels: surface expression of granule markers by flow cytometry; release of matrix metallopeptidase-9 (MMP-9 or gelatinase B) enzyme into supernatants by Western blot; and gelatinase B activity by zymography. Activation of p38 MAPK was studied by monitoring its tyrosine phosphorylation levels by western blot and its role by the utilization of a pharmacological inhibitor. The results indicate that curcumin increased the cell surface expression of CD35 (secretory vesicle), CD63 (azurophilic granules), and CD66b (gelatinase granules) in neutrophils. Also, curcumin increased the release and enzymatic activity of gelatinase B in the extracellular milieu and activated p38 MAP kinase in these cells. However, in contrast to fMLP, curcumin-induced enzymatic activity and secretion of gelatinase B were not reversed by use of a p38 inhibitor. Finally, it was found that curcumin was able to enhance phagocytosis. Taken together, the results here demonstrate that curcumin induced degranulation in human neutrophils and that the increased gelatinase activity is not dependent on p38 MAPK activation. Therefore, degranulation is another human neutrophil function that could be modulated by curcumin, as well as phagocytosis. PMID:24926560

  11. Deoxycholic acid mediates non-canonical EGFR-MAPK activation through the induction of calcium signaling in colon cancer cells.

    PubMed

    Centuori, Sara M; Gomes, Cecil J; Trujillo, Jesse; Borg, Jamie; Brownlee, Joshua; Putnam, Charles W; Martinez, Jesse D

    2016-07-01

    Obesity and a western diet have been linked to high levels of bile acids and the development of colon cancer. Specifically, increased levels of the bile acid deoxycholic acid (DCA), an established tumor promoter, has been shown to correlate with increased development of colorectal adenomas and progression to carcinoma. Herein we investigate the mechanism by which DCA leads to EGFR-MAPK activation, a candidate mechanism by which DCA may promote colorectal tumorigenesis. DCA treated colon cancer cells exhibited strong and prolonged activation of ERK1/2 when compared to EGF treatment alone. We also showed that DCA treatment prevents EGFR degradation as opposed to the canonical EGFR recycling observed with EGF treatment. Moreover, the combination of DCA and EGF treatment displayed synergistic activity, suggesting DCA activates MAPK signaling in a non-canonical manner. Further evaluation showed that DCA treatment increased intracellular calcium levels and CAMKII phosphorylation, and that blocking calcium with BAPTA-AM abrogated MAPK activation induced by DCA, but not by EGF. Finally we showed that DCA-induced CAMKII leads to MAPK activation through the recruitment of c-Src. Taken together, we demonstrated that DCA regulates MAPK activation through calcium signaling, an alternative mechanism not previously recognized in human colon cancer cells. Importantly, this mechanism allows for EGFR to escape degradation and thus achieve a constitutively active state, which may explain its tumor promoting effects. PMID:27086143

  12. Extracellular ATP activates MAPK and ROS signaling during injury response in the fungus Trichoderma atroviride

    PubMed Central

    Medina-Castellanos, Elizabeth; Esquivel-Naranjo, Edgardo U.; Heil, Martin; Herrera-Estrella, Alfredo

    2014-01-01

    The response to mechanical damage is crucial for the survival of multicellular organisms, enabling their adaptation to hostile environments. Trichoderma atroviride, a filamentous fungus of great importance in the biological control of plant diseases, responds to mechanical damage by activating regenerative processes and asexual reproduction (conidiation). During this response, reactive oxygen species (ROS) are produced by the NADPH oxidase complex. To understand the underlying early signaling events, we evaluated molecules such as extracellular ATP (eATP) and Ca2+ that are known to trigger wound-induced responses in plants and animals. Concretely, we investigated the activation of mitogen-activated protein kinase (MAPK) pathways by eATP, Ca2+, and ROS. Indeed, application of exogenous ATP and Ca2+ triggered conidiation. Furthermore, eATP promoted the Nox1-dependent production of ROS and activated a MAPK pathway. Mutants in the MAPK-encoding genes tmk1 and tmk3 were affected in wound-induced conidiation, and phosphorylation of both Tmk1 and Tmk3 was triggered by eATP. We conclude that in this fungus, eATP acts as a damage-associated molecular pattern (DAMP). Our data indicate the existence of an eATP receptor and suggest that in fungi, eATP triggers pathways that converge to regulate asexual reproduction genes that are required for injury-induced conidiation. By contrast, Ca2+ is more likely to act as a downstream second messenger. The early steps of mechanical damage response in T. atroviride share conserved elements with those known from plants and animals. PMID:25484887

  13. Activation of ERK induces phosphorylation of MAPK phosphatase-7, a JNK specific phosphatase, at Ser-446.

    PubMed

    Masuda, Kouhei; Shima, Hiroshi; Katagiri, Chiaki; Kikuchi, Kunimi

    2003-08-22

    We previously showed that MKP-7 suppresses MAPK activation in COS-7 cells in the order of selectivity, JNK > p38 > ERK, but interacts with ERK as well as JNK and p38. In this study we found that, when expressed in COS-7 cells with HA-ERK2, the mobility of FLAG-MKP-7 was decreased on SDS-PAGE gels depending on several stimuli, including phorbol 12-myristate 13-acetate, fetal bovine serum, epidermal growth factor, H2O2, and ionomycin. By using U0126, a MEK inhibitor, and introducing several point mutations, we demonstrated that this upward mobility shift is because of phosphorylation and identified Ser-446 of MKP-7 as the phosphorylation site targeted by ERK activation. To determine how MKP-7 interacts with MAPKs, we identified three domains in MKP-7 required for interaction with MAPKs, namely, putative MAP kinase docking domains (D-domain) I and II and a long COOH-terminal stretch unique to MKP-7. The D-domain I is required for interaction with ERK and p38, whereas the D-domain II is required for interaction with JNK and p38, which is likely to be important for MKP-7 to suppress JNK and p38 activations. The COOH-terminal stretch of MKP-7 was shown to determine JNK preference for MKP-7 by masking MKP-7 activity toward p38 and is a domain bound by ERK. These data strongly suggested that Ser-446 of MKP-7 is phosphorylated by ERK. PMID:12794087

  14. Aluminum Nanoparticles Induce ERK and p38MAPK Activation in Rat Brain.

    PubMed

    Kwon, Jung-Taek; Seo, Gyun-Baek; Jo; Lee, Mimi; Kim, Hyun-Mi; Shim, Ilseob; Lee, Byung-Woo; Yoon, Byung-Il; Kim, Pilje; Choi, Kyunghee

    2013-09-01

    Aluminum nanoparticles (Al-NPs) are one of the most widely used nanomaterial in cosmetics and medical materials. For this reason, Al-NP exposure is very likely to occur via inhalation in the environment and the workplace. Nevertheless, little is known about the mechanism of Al-NP neurotoxicity via inhalation exposure. In this study, we investigated the effect AL-NPs on the brain. Rats were exposed to Al-NPs by nasal instillation at 1 mg/kg body weight (low exposure group), 20 mg/kg body weight (moderate exposure group), and 40 mg/kg body weight (high exposure group), for a total of 3 times, with a 24-hr interval after each exposure. Inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated that the presence of aluminum was increased in a dose-dependent manner in the olfactory bulb (OFB) and the brain. In microarray analysis, the regulation of mitogen-activated protein kinases (MAPK) activity (GO: 0043405), including Ptprc, P2rx7, Map2k4, Trib3, Trib1, and Fgd4 was significantly over-expressed in the treated mice than in the controls (p = 0.0027). Moreover, Al-NPs induced the activation of ERK1 and p38 MAPK protein expression in the brain, but did not alter the protein expression of JNK, when compared to the control. These data demonstrate that the nasal exposure of Al-NPs can permeate the brain via the olfactory bulb and modulate the gene and protein expression of MAPK and its activity. PMID:24386518

  15. Aluminum Nanoparticles Induce ERK and p38MAPK Activation in Rat Brain

    PubMed Central

    Seo, Gyun-Baek; Jo; Lee, Mimi; Shim, Ilseob; Lee, Byung-Woo; Yoon, Byung-Il; Kim, Pilje; Choi, Kyunghee

    2013-01-01

    Aluminum nanoparticles (Al-NPs) are one of the most widely used nanomaterial in cosmetics and medical materials. For this reason, Al-NP exposure is very likely to occur via inhalation in the environment and the workplace. Nevertheless, little is known about the mechanism of Al-NP neurotoxicity via inhalation exposure. In this study, we investigated the effect AL-NPs on the brain. Rats were exposed to Al-NPs by nasal instillation at 1 mg/kg body weight (low exposure group), 20 mg/kg body weight (moderate exposure group), and 40 mg/kg body weight (high exposure group), for a total of 3 times, with a 24-hr interval after each exposure. Inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated that the presence of aluminum was increased in a dose-dependent manner in the olfactory bulb (OFB) and the brain. In microarray analysis, the regulation of mitogen-activated protein kinases (MAPK) activity (GO: 0043405), including Ptprc, P2rx7, Map2k4, Trib3, Trib1, and Fgd4 was significantly over-expressed in the treated mice than in the controls (p = 0.0027). Moreover, Al-NPs induced the activation of ERK1 and p38 MAPK protein expression in the brain, but did not alter the protein expression of JNK, when compared to the control. These data demonstrate that the nasal exposure of Al-NPs can permeate the brain via the olfactory bulb and modulate the gene and protein expression of MAPK and its activity. PMID:24386518

  16. 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

  17. Activated p38 MAPK in Peripheral Blood Monocytes of Steroid Resistant Asthmatics

    PubMed Central

    Li, Ling-bo; Leung, Donald Y. M.; Goleva, Elena

    2015-01-01

    Steroid resistance is a significant problem in management of chronic inflammatory diseases, including asthma. Accessible biomarkers are needed to identify steroid resistant patients to optimize their treatment. This study examined corticosteroid resistance in severe asthma. 24 asthmatics with forced expiratory volume in one second of less then 80% predicted were classified as steroid resistant or steroid sensitive based on changes in their lung function following a week of treatment with oral prednisone. Heparinised blood was collected from patients prior to oral prednisone administration. Phosphorylated mitogen activated kinases (MAPK) (extracellular regulated kinase (ERK), p38 and jun kinase (JNK)) were analyzed in whole blood samples using flow cytometry. Activation of phospho-p38 MAPK and phospho-mitogen- and stress-activated protein kinase 1 (MSK1) in asthmatics’ peripheral blood mononuclear cells (PBMC) were confirmed by Western blot. Dexamethasone suppression of the LPS-induced IL-8 mRNA production by steroid resistant asthmatics PBMC in the presence of p38 and ERK inhibitors was evaluated by real time PCR. Flow cytometry analysis identified significantly stronger p38 phosphorylation in CD14+ monocytes from steroid resistant than steroid sensitive asthmatics (p = 0.014), whereas no difference was found in phosphorylation of ERK or JNK in CD14+ cells from these two groups of asthmatics. No difference in phosphorylated p38, ERK, JNK was detected in CD4+, CD8+ T cells, B cells and NK cells from steroid resistant vs. steroid sensitive asthmatics. P38 MAPK pathway activation was confirmed by Western blot, as significantly higher phospho-p38 and phospho-MSK1 levels were detected in the PBMC lysates from steroid resistant asthmatics. P38 inhibitor significantly enhanced DEX suppression of LPS-induced IL-8 mRNA by PBMC of steroid resistant asthmatics. This is the first report demonstrating selective p38 MAPK pathway activation in blood monocytes of steroid

  18. Amarogentin, a Secoiridoid Glycoside, Abrogates Platelet Activation through PLCγ2-PKC and MAPK Pathways

    PubMed Central

    Yen, Ting-Lin; Lu, Wan-Jung; Lien, Li-Ming; Thomas, Philip Aloysius; Lee, Tzu-Yin; Chiu, Hou-Chang; Sheu, Joen-Rong

    2014-01-01

    Amarogentin, an active principle of Gentiana lutea, possess antitumorigenic, antidiabetic, and antioxidative properties. Activation of platelets is associated with intravascular thrombosis and cardiovascular diseases. The present study examined the effects of amarogentin on platelet activation. Amarogentin treatment (15~60 μM) inhibited platelet aggregation induced by collagen, but not thrombin, arachidonic acid, and U46619. Amarogentin inhibited collagen-induced phosphorylation of phospholipase C (PLC)γ2, protein kinase C (PKC), and mitogen-activated protein kinases (MAPKs). It also inhibits in vivo thrombus formation in mice. In addition, neither the guanylate cyclase inhibitor ODQ nor the adenylate cyclase inhibitor SQ22536 affected the amarogentin-mediated inhibition of platelet aggregation, which suggests that amarogentin does not regulate the levels of cyclic AMP and cyclic GMP. In conclusion, amarogentin prevents platelet activation through the inhibition of PLCγ2-PKC cascade and MAPK pathway. Our findings suggest that amarogentin may offer therapeutic potential for preventing or treating thromboembolic disorders. PMID:24868545

  19. PKC theta and p38 MAPK activate the EBV lytic cycle through autophagy induction.

    PubMed

    Gonnella, Roberta; Granato, Marisa; Farina, Antonella; Santarelli, Roberta; Faggioni, Alberto; Cirone, Mara

    2015-07-01

    PKC activation by combining TPA with sodium butyrate (T/B) represents the most effective and widely used strategy to induce the Epstein-Barr virus (EBV) lytic cycle. The results obtained in this study show that novel PKCθ is involved in such process and that it acts through the activation of p38 MAPK and autophagy induction. Autophagy, a mechanism of cellular defense in stressful conditions, is manipulated by EBV to enhance viral replication. Besides promoting the EBV lytic cycle, the activation of p38 and autophagy resulted in a pro-survival effect, as indicated by p38 or ATG5 knocking down experiments. However, this pro-survival role was counteracted by a pro-death activity of PKCθ, due to the dephosphorylation of AKT. In conclusion, this study reports, for the first time, that T/B activates a PKCθ-p38 MAPK axis in EBV infected B cells, that promotes the viral lytic cycle and cell survival and dephosphorylates AKT, balancing cell life and cell death. PMID:25827954

  20. TLR4-Activated MAPK-IL-6 Axis Regulates Vascular Smooth Muscle Cell Function.

    PubMed

    Lee, Guan-Lin; Wu, Jing-Yiing; Tsai, Chien-Sung; Lin, Chih-Yuan; Tsai, Yi-Ting; Lin, Chin-Sheng; Wang, Yi-Fu; Yet, Shaw-Fang; Hsu, Yu-Juei; Kuo, Cheng-Chin

    2016-01-01

    Migration of vascular smooth muscle cells (VSMCs) into the intima is considered to be a vital event in the pathophysiology of atherosclerosis. Despite substantial evidence supporting the pathogenic role of Toll-like receptor 4 (TLR4) in the progression of atherogenesis, its function in the regulation of VSMC migration remains unclear. The goal of the present study was to elucidate the mechanism by which TLR4 regulates VSMC migration. Inhibitor experiments revealed that TLR4-induced IL-6 secretion and VSMC migration were mediated via the concerted actions of MyD88 and TRIF on the activation of p38 MAPK and ERK1/2 signaling. Neutralizing anti-IL-6 antibodies abrogated TLR4-driven VSMC migration and F-actin polymerization. Blockade of p38 MAPK or ERK1/2 signaling cascade inhibited TLR4 agonist-mediated activation of cAMP response element binding protein (CREB). Moreover, siRNA-mediated suppression of CREB production repressed TLR4-induced IL-6 production and VSMC migration. Rac-1 inhibitor suppressed TLR4-driven VSMC migration but not IL-6 production. Importantly, the serum level of IL-6 and TLR4 endogenous ligand HMGB1 was significantly higher in patients with coronary artery diseases (CAD) than in healthy subjects. Serum HMGB1 level was positively correlated with serum IL-6 level in CAD patients. The expression of both HMGB1 and IL-6 was clearly detected in the atherosclerotic tissue of the CAD patients. Additionally, there was a positive association between p-CREB and HMGB1 in mouse atherosclerotic tissue. Based on our findings, we concluded that, upon ligand binding, TLR4 activates p38 MAPK and ERK1/2 signaling through MyD88 and TRIF in VSMCs. These signaling pathways subsequently coordinate an additive augmentation of CREB-driven IL-6 production, which in turn triggers Rac-1-mediated actin cytoskeleton to promote VSMC migration. PMID:27563891

  1. Activation of Egr-1 in Human Lung Epithelial Cells Exposed to Silica through MAPKs Signaling Pathways

    PubMed Central

    Chu, Ling; Wang, Tiansheng; Hu, Yongbin; Gu, Yonghong; Su, Zanshan; Jiang, Haiying

    2013-01-01

    The alveolar type II epithelial cell, regarded historically as a key target cell in initial injury by silica, now appears to be important in both defense from lung damage as well as elaboration of chemokines and cytokines. The molecular basis for silica-induced epithelial cell injury is poorly understood. In this study we explored the activation of nuclear factor Egr-1 and related signal pathway. Human II alveolar epithelial line A549 cells were exposed to silica for indicated time to assay the expression and activation of Egr-1 and upstream MAPKs. Immunofluorescence, western-blot techniques, RT-PCR, Electrophoretic mobility shift assay (EMSA), transient transfection assay, kinase inhibitor experiments were performed. It was found that the expression of Egr-1 at mRNA and protein level was significantly increased in A549 cells after administration with silica and the activity of Egr-1 peaked by silica treatment for 60 minutes. Furthermore, phosphorylated-ERK1/2, P38 MAPKs (the upstream kinase of Egr-1) ballooned during 15-30minutes, 30-60minutes respectively after silica exposure in A549 cells. By administration of ERK1/2, P38 inhibitor, the expression and transcription of Egr-1 were both markedly decreased. But PKC inhibitor did not prevent the increase of Egr-1. These results indicated Egr-1 played a critical role in silica-induced pulmonary fibrosis in an ERK1/2, P38 MAPKs-dependent manner, which suggests Egr-1 is an essential regulator in silicosis, and underlines a new molecular mechanism for fibrosis induced by silica. PMID:23874821

  2. Activation of the MAPK/ERK Cell-Signaling Pathway in Uterine Smooth Muscle Cells of Women With Adenomyosis.

    PubMed

    Streuli, Isabelle; Santulli, Pietro; Chouzenoux, Sandrine; Chapron, Charles; Batteux, Frédéric

    2015-12-01

    We investigated whether the myometrium might be intrinsically different in women with adenomyosis. We studied whether the mitogen-activated protein kinases/extracellular signal-regulated kinases (MAPKs/ERKs) and phosphoinositide 3-kinase/mammalian target of rapamycin/AKT (PI3K/mTOR/AKT) cell-signaling pathways, implicated in the pathogenesis of endometriosis, might also be activated in uterine smooth muscle cells (uSMCs) of women with adenomyosis and measured the production of reactive oxygen species (ROS), proinflammatory mediators that modulate cell proliferation and have been shown to activate the MAPK/ERK pathway in endometriosis. The uSMC cultures were derived from myometrium biopsies obtained during hysterectomy or myomectomy in women with adenomyosis and controls with leiomyoma. Proliferation of uSMCs and in vitro activation of the MAPK/ERK cell-signaling pathway were increased in women with adenomyosis compared to controls. The activation of the PI3K/mTOR/AKT pathway was not significant. The ROS production and ROS detoxification pathways were not different between uSMCs of women with adenomyosis and controls suggesting an ROS-independent activation of the MAPK/ERK pathway. Our results also provide evidence that protein kinase inhibitors and the rapanalogue temsirolimus can control proliferation of uSMCs in vitro suggesting an implication of the MAPK/ERK and the PI3K/mTOR/AKT pathways in proliferation of uSMCs in women with adenomyosis and leiomyomas. PMID:26071388

  3. MEK Inhibition Overcomes Cisplatin Resistance Conferred by SOS/MAPK Pathway Activation in Squamous Cell Carcinoma.

    PubMed

    Kong, Li Ren; Chua, Kian Ngiap; Sim, Wen Jing; Ng, Hsien Chun; Bi, Chonglei; Ho, Jingshan; Nga, Min En; Pang, Yin Huei; Ong, Weijie Richard; Soo, Ross Andrew; Huynh, Hung; Chng, Wee Joo; Thiery, Jean-Paul; Goh, Boon Cher

    2015-07-01

    Genomic analyses of squamous cell carcinoma (SCC) have yet to yield significant strategies against pathway activation to improve treatment. Platinum-based chemotherapy remains the mainstay of treatment for SCC of different histotypes either as a single-agent or alongside other chemotherapeutic drugs or radiotherapy; however, resistance inevitably emerges, which limits the duration of treatment response. To elucidate mechanisms that mediate resistance to cisplatin, we compared drug-induced perturbations to gene and protein expression between cisplatin-sensitive and -resistant SCC cells, and identified MAPK-ERK pathway upregulation and activation in drug-resistant cells. ERK-induced resistance appeared to be activated by Son of Sevenless (SOS) upstream, and mediated through Bim degradation downstream. Clinically, elevated p-ERK expression was associated with shorter disease-free survival in patients with locally advanced head and neck SCC treated with concurrent chemoradiation. Inhibition of MEK/ERK, but not that of EGFR or RAF, augmented cisplatin sensitivity in vitro and demonstrated efficacy and tolerability in vivo. Collectively, these findings suggest that inhibition of the activated SOS-MAPK-ERK pathway may augment patient responses to cisplatin treatment. PMID:25939760

  4. Exocyst Sec10 protects renal tubule cells from injury by EGFR/MAPK activation and effects on endocytosis

    PubMed Central

    Fogelgren, Ben; Zuo, Xiaofeng; Buonato, Janine M.; Vasilyev, Aleksandr; Baek, Jeong-In; Choi, Soo Young; Chacon-Heszele, Maria F.; Palmyre, Aurélien; Polgar, Noemi; Drummond, Iain; Park, Kwon Moo; Lazzara, Matthew J.

    2014-01-01

    Acute kidney injury is common and has a high mortality rate, and no effective treatment exists other than supportive care. Using cell culture models, we previously demonstrated that exocyst Sec10 overexpression reduced damage to renal tubule cells and speeded recovery and that the protective effect was mediated by higher basal levels of mitogen-activated protein kinase (MAPK) signaling. The exocyst, a highly-conserved eight-protein complex, is known for regulating protein trafficking. Here we show that the exocyst biochemically interacts with the epidermal growth factor receptor (EGFR), which is upstream of MAPK, and Sec10-overexpressing cells express greater levels of phosphorylated (active) ERK, the final step in the MAPK pathway, in response to EGF stimulation. EGFR endocytosis, which has been linked to activation of the MAPK pathway, increases in Sec10-overexpressing cells, and gefitinib, a specific EGFR inhibitor, and Dynasore, a dynamin inhibitor, both reduce EGFR endocytosis. In turn, inhibition of the MAPK pathway reduces ligand-mediated EGFR endocytosis, suggesting a potential feedback of elevated ERK activity on EGFR endocytosis. Gefitinib also decreases MAPK signaling in Sec10-overexpressing cells to levels seen in control cells and, demonstrating a causal role for EGFR, reverses the protective effect of Sec10 overexpression following cell injury in vitro. Finally, using an in vivo zebrafish model of acute kidney injury, morpholino-induced knockdown of sec10 increases renal tubule cell susceptibility to injury. Taken together, these results suggest that the exocyst, acting through EGFR, endocytosis, and the MAPK pathway is a candidate therapeutic target for acute kidney injury. PMID:25298525

  5. Measurement of constitutive MAPK and PI3K/AKT signaling activity in human cancer cell lines

    PubMed Central

    Paraiso, Kim H.T.; Van Der Kooi, Kaisa; Messina, Jane L.; Smalley, Keiran S. M.

    2014-01-01

    The growth and survival of cancer cells is often driven by constitutive activity in the mitogen activated protein kinase (MAPK) and phospho-inositide 3-kinase (PI3K)/AKT signaling pathways. Activity in these signal transduction cascades is known to contribute to the uncontrolled growth and resistance to apoptosis that characterizes tumor progression. There is now a great deal of interest in therapeutically targeting these pathways in cancer using small molecule inhibitors. In this chapter we describe methods to measure constitutive MAPK and AKT activity in melanoma cell lines, with a focus upon Western blotting, phospho-flow cytometry and immunofluorescence staining techniques. PMID:21036250

  6. Metabolic Respiration Induces AMPK- and Ire1p-Dependent Activation of the p38-Type HOG MAPK Pathway

    PubMed Central

    Adhikari, Hema; Cullen, Paul J.

    2014-01-01

    Evolutionarily conserved mitogen activated protein kinase (MAPK) pathways regulate the response to stress as well as cell differentiation. In Saccharomyces cerevisiae, growth in non-preferred carbon sources (like galactose) induces differentiation to the filamentous cell type through an extracellular-signal regulated kinase (ERK)-type MAPK pathway. The filamentous growth MAPK pathway shares components with a p38-type High Osmolarity Glycerol response (HOG) pathway, which regulates the response to changes in osmolarity. To determine the extent of functional overlap between the MAPK pathways, comparative RNA sequencing was performed, which uncovered an unexpected role for the HOG pathway in regulating the response to growth in galactose. The HOG pathway was induced during growth in galactose, which required the nutrient regulatory AMP-dependent protein kinase (AMPK) Snf1p, an intact respiratory chain, and a functional tricarboxylic acid (TCA) cycle. The unfolded protein response (UPR) kinase Ire1p was also required for HOG pathway activation in this context. Thus, the filamentous growth and HOG pathways are both active during growth in galactose. The two pathways redundantly promoted growth in galactose, but paradoxically, they also inhibited each other's activities. Such cross-modulation was critical to optimize the differentiation response. The human fungal pathogen Candida albicans showed a similar regulatory circuit. Thus, an evolutionarily conserved regulatory axis links metabolic respiration and AMPK to Ire1p, which regulates a differentiation response involving the modulated activity of ERK and p38 MAPK pathways. PMID:25356552

  7. Manganese modulation of MAPK pathways: effects on upstream mitogen activated protein kinase kinases (MKKs) and mitogen activated kinase phosphatase-1 (MKP-1) in microglial cells

    PubMed Central

    Crittenden, Patrick L.; Filipov, Nikolay M.

    2010-01-01

    Multiple studies demonstrate that manganese (Mn) exposure potentiates inflammatory mediator output from activated glia; this increased output is associated with enhanced mitogen activated protein kinase (MAPK: p38, ERK, and JNK) activity. We hypothesized that Mn activates MAPK by activating the kinases upstream of MAPK, i.e., MKK-3/6, MKK-1/2, and MKK-4 (responsible for activation of p38, ERK, and JNK, respectively), and/or by inhibiting a major phosphatase responsible for MAPK inactivation, MKP-1. Exposure of N9 microglia to Mn (250μM), LPS (100 ng/ml), or Mn+LPS increased MKK-3/6 and MKK-4 activity at 1 h; the effect of Mn+LPS on MKK-4 activation was greater than the rest. At 4 h, Mn, LPS, and Mn+LPS increased MKK-3/6 and MKK-1/2 phosphorylation, whereas MKK-4 was activated only by Mn and Mn+LPS. Besides activating MKK-4 via Ser257/Thr261 phosphorylation, Mn (4 h) prevented MKK-4’s phosphorylation on Ser80, which negatively regulates MKK-4 activity. Exposure to Mn or Mn+LPS (1 h) decreased both mRNA and protein expression of MKP-1, the negative MAPK regulator. In addition, we observed that at 4 h, but not at 1 h, a time point coinciding with increased MAPK activity, Mn+LPS markedly increased TNF-α , IL-6, and Cox-2 mRNA, suggesting a delayed effect. The fact that all three major groups of MKKs, MKK-1/2, MKK-3/6, and MKK-4 are activated by Mn suggests that Mn-induced activation of MAPK occurs via traditional mechanisms, which perhaps involve the MAPKs farthest upstream, MKKKs (MAP3Ks). In addition, for all MKKs, Mn-induced activation was persistent at least for 4 h, indicating a long-term effect. PMID:20589745

  8. Involvement of Ras/Raf/AP-1 in BMP-4 signaling during Xenopus embryonic development.

    PubMed Central

    Xu, R H; Dong, Z; Maeno, M; Kim, J; Suzuki, A; Ueno, N; Sredni, D; Colburn, N H; Kung, H F

    1996-01-01

    Previously, we elucidated the role of bone morphogenetic protein 4 (BMP-4) in the dorsal-ventral patterning of the Xenopus embryo by using a dominant negative mutant of the BMP-4 receptor (DN-BR). The present paper describes the involvement of Ras, Raf, and activator protein 1 (AP-1) in BMP-4 signaling during Xenopus embryonic development. The AP-1 activity was determined by injecting an AP-1-dependent luciferase reporter gene into two-cell-stage Xenopus embryos and measuring the luciferase activity at various developmental stages. We found that injection of BMP-4 mRNA increased AP-1 activity, whereas injection of DN-BR mRNA inhibited AP-1 activity. Similar inhibitory effects were seen with injection of mRNAs encoding dominant negative mutants of c-Ha-Ras, c-Raf, or c-Jun. These results suggest that the endogenous AP-1 activity is regulated by BMP-4/Ras/Raf/Jun signals. We next investigated the effects of Ras/Raf/AP-1 signals on the biological functions of BMP-4. DN-BR-induced dorsalization of the embryo, revealed by the formation of a secondary body axis or dorsalization of the ventral mesoderm explant analyzed by histological and molecular criteria, was significantly reversed by coinjection of [Val12]Ha-Ras, c-Raf, or c-Jun mRNA. Furthermore, the BMP-4-stimulated erythroid differentiation in the ventral mesoderm was substantially inhibited by coinjection with the dominant negative c-Ha-Ras, c-Raf, or c-Jun mutant. Our results suggest the involvement of Ras/Raf/AP-1 in the BMP-4 signaling pathway. Images Fig. 2 Fig. 3 Fig. 4 PMID:8570644

  9. Xenopus H-RasV12 promotes entry into meiotic M phase and cdc2 activation independently of Mos and p42(MAPK).

    PubMed

    Dupré, Aude; Suziedelis, Kestutis; Valuckaite, Ryte; de Gunzburg, Jean; Ozon, René; Jessus, Catherine; Haccard, Olivier

    2002-09-19

    In the Xenopus oocyte, progesterone triggers M phase Promoting Factor (MPF) activation in a protein synthesis dependent manner. Although the synthesis of the p42(MAPK) activator Mos appears to be required for MPF activation, p42(MAPK) activity has been shown to be dispensable. To clarify this paradox, we attempted to activate the p42(MAPK) pathway independently of Mos synthesis by cloning and using Xenopus H-Ras in the oocyte. We demonstrate that the injection of the constitutively active Xe H-RasV12 mutant induces p42(MAPK) and MPF activation through two independent pathways. Xe H-RasV12 induces only a partial activation of p42(MAPK) when protein synthesis and MPF activation are prevented. A full level of p42(MAPK) activation is reached when MPF is activated and Mos is present. In contrast, MPF activation induced by Xe H-RasV12 is achieved independently of Mos synthesis and p42(MAPK) activation but still depends on protein synthesis. Therefore, the amphibian oocyte represents a new model system to analyse an original H-Ras pathway ending to MPF activation and distinct from the p42(MAPK) pathway. The identification of the proteins synthesized in response to Xe H-RasV12 and required for MPF activation, represents an important clue in understanding the mechanism of progesterone action. PMID:12226746

  10. Genome-Wide Survey and Expression Profile Analysis of the Mitogen-Activated Protein Kinase (MAPK) Gene Family in Brassica rapa

    PubMed Central

    Yu, Hao; Qu, Cunmin; Tang, Zhanglin; Li, Jiana; Chai, Yourong; Liang, Ying

    2015-01-01

    Mitogen-activated protein kinase (MAPK) cascades are fundamental signal transduction modules in plants, controlling cell division, development, hormone signaling, and biotic and abiotic stress responses. Although MAPKs have been investigated in several plant species, a comprehensive analysis of the MAPK gene family has hitherto not been performed in Brassica rapa. In this study, we identified 32 MAPKs in the B. rapa genome by conducting BLASTP and syntenic block analyses, and screening for the essential signature motif (TDY or TEY) of plant MAPK proteins. Of the 32 BraMAPK genes retrieved from the Brassica Database, 13 exhibited exon splicing errors, excessive splicing of the 5' sequence, excessive retention of the 5' sequence, and sequencing errors of the 3' end. Phylogenetic trees of the 32 corrected MAPKs from B. rapa and of MAPKs from other plants generated by the neighbor-joining and maximum likelihood methods suggested that BraMAPKs could be divided into four groups (groups A, B, C, and D). Gene number expansion was observed for BraMAPK genes in groups A and D, which may have been caused by the tandem duplication and genome triplication of the ancestral genome of the Brassica progenitor. Except for five members of the BraMAPK10 subfamily, the identified BraMAPKs were expressed in most of the tissues examined, including callus, root, stem, leaf, flower, and silique. Quantitative real-time PCR demonstrated that at least six and five BraMAPKs were induced or repressed by various abiotic stresses and hormone treatments, respectively, suggesting their potential roles in the abiotic stress response and various hormone signal transduction pathways in B. rapa. This study provides valuable insight into the putative physiological and biochemical functions of MAPK genes in B. rapa. PMID:26173020

  11. Genome-Wide Survey and Expression Profile Analysis of the Mitogen-Activated Protein Kinase (MAPK) Gene Family in Brassica rapa.

    PubMed

    Lu, Kun; Guo, Wenjin; Lu, Junxing; Yu, Hao; Qu, Cunmin; Tang, Zhanglin; Li, Jiana; Chai, Yourong; Liang, Ying

    2015-01-01

    Mitogen-activated protein kinase (MAPK) cascades are fundamental signal transduction modules in plants, controlling cell division, development, hormone signaling, and biotic and abiotic stress responses. Although MAPKs have been investigated in several plant species, a comprehensive analysis of the MAPK gene family has hitherto not been performed in Brassica rapa. In this study, we identified 32 MAPKs in the B. rapa genome by conducting BLASTP and syntenic block analyses, and screening for the essential signature motif (TDY or TEY) of plant MAPK proteins. Of the 32 BraMAPK genes retrieved from the Brassica Database, 13 exhibited exon splicing errors, excessive splicing of the 5' sequence, excessive retention of the 5' sequence, and sequencing errors of the 3' end. Phylogenetic trees of the 32 corrected MAPKs from B. rapa and of MAPKs from other plants generated by the neighbor-joining and maximum likelihood methods suggested that BraMAPKs could be divided into four groups (groups A, B, C, and D). Gene number expansion was observed for BraMAPK genes in groups A and D, which may have been caused by the tandem duplication and genome triplication of the ancestral genome of the Brassica progenitor. Except for five members of the BraMAPK10 subfamily, the identified BraMAPKs were expressed in most of the tissues examined, including callus, root, stem, leaf, flower, and silique. Quantitative real-time PCR demonstrated that at least six and five BraMAPKs were induced or repressed by various abiotic stresses and hormone treatments, respectively, suggesting their potential roles in the abiotic stress response and various hormone signal transduction pathways in B. rapa. This study provides valuable insight into the putative physiological and biochemical functions of MAPK genes in B. rapa. PMID:26173020

  12. Endothelium-Derived 5-Methoxytryptophan Protects Endothelial Barrier Function by Blocking p38 MAPK Activation

    PubMed Central

    Chu, Ling-Yun; Wang, Yi-Fu; Cheng, Huei-Hsuan; Kuo, Cheng-Chin; Wu, Kenneth K.

    2016-01-01

    The endothelial junction is tightly controlled to restrict the passage of blood cells and solutes. Disruption of endothelial barrier function by bacterial endotoxins, cytokines or growth factors results in inflammation and vascular damage leading to vascular diseases. We have identified 5-methoxytryptophan (5-MTP) as an anti-inflammatory factor by metabolomic analysis of conditioned medium of human fibroblasts. Here we postulated that endothelial cells release 5-MTP to protect the barrier function. Conditioned medium of human umbilical vein endothelial cells (HUVECs) prevented endothelial hyperpermeability and VE-cadherin downregulation induced by VEGF, LPS and cytokines. We analyzed the metabolomic profile of HUVEC conditioned medium and detected 5-MTP but not melatonin, serotonin or their catabolites, which was confirmed by enzyme-linked immunosorbent assay. Addition of synthetic pure 5-MTP preserved VE-cadherin and maintained barrier function despite challenge with pro-inflammatory mediators. Tryptophan hydroxylase-1, an enzyme required for 5-MTP biosynthesis, was downregulated in HUVECs by pro-inflammatory mediators and it was accompanied by reduction of 5-MTP. 5-MTP protected VE-cadherin and prevented endothelial hyperpermeability by blocking p38 MAPK activation. A chemical inhibitor of p38 MAPK, SB202190, exhibited a similar protective effect as 5-MTP. To determine whether 5-MTP prevents vascular hyperpermeability in vivo, we evaluated the effect of 5-MTP administration on LPS-induced murine microvascular permeability with Evans blue. 5-MTP significantly prevented Evans blue dye leakage. Our findings indicate that 5-MTP is a new class of endothelium-derived molecules which protects endothelial barrier function by blocking p38 MAPK. PMID:27002329

  13. Prenatal choline supplementation advances hippocampal development and enhances MAPK and CREB activation.

    PubMed

    Mellott, Tiffany J; Williams, Christina L; Meck, Warren H; Blusztajn, Jan Krzysztof

    2004-03-01

    Choline is an essential nutrient for animals and humans. Previous studies showed that supplementing the maternal diet with choline during the second half of gestation in rats permanently enhances memory performance of the adult offspring. Here we show that prenatal choline supplementation causes a 3-day advancement in the ability of juvenile rats to use relational cues in a water maze task, indicating that the treatment accelerates hippocampal maturation. Moreover, phosphorylation and therefore activation of hippocampal mitogen-activated protein kinase (MAPK) and cAMP-response element binding protein (CREB) in response to stimulation by glutamate, N-methyl-D-aspartate, or depolarizing concentrations of K+ were increased by prenatal choline supplementation and reduced by prenatal choline deficiency. These data provide the first evidence that developmental plasticity of the hippocampal MAPK and CREB signaling pathways is controlled by the supply of a single essential nutrient, choline, during fetal development and point to these pathways as candidate mechanisms for the developmental and long-term cognitive enhancement induced by prenatal choline supplementation. PMID:14715695

  14. MALT1 Inhibition of Oral Carcinoma Cell Invasion and ERK/MAPK Activation.

    PubMed

    Chiba, T; Soeno, Y; Shirako, Y; Sudo, H; Yagishita, H; Taya, Y; Kawashiri, S; Okada, Y; Imai, K

    2016-04-01

    The expression of mucosa-associated lymphoid tissue 1 (MALT1) that activates nuclear factor (NF)-κB in lymphocyte lineages is rapidly inactivated in oral carcinoma cells at the invasive front and the patients with worst prognosis. However, its mechanism to accelerate carcinoma progression remains unknown, and this study was carried out to examine the role in invasion. HSC2 oral carcinoma cells stably expressing wild-type MALT1 (wtMALT1) reduced the invasion of basement membrane matrices and collagen gels, and the dominant-negative form (∆MALT1)-expressing cells aggressively invaded into collagen gels. MALT1 decelerated proliferation and migration of cells and downregulated expression of matrix metalloproteinase 2 and 9, which were confirmed by short interfering RNA transfections. Reporter assays and immunoblot analysis showed that MALT1 does not affect the NF-κB pathway but inhibits ERK/MAPK activation. This was confirmed by endogenous MALT1 expression in oral carcinoma cell lines. Orthotopic implantation of ∆MALT1-expressing HSC2 cells in mice grew rapid expansive and invasive tongue tumors in contrast to an absence of tumor formation by wtMALT1-expressing cells. These results demonstrate that MALT1 suppresses oral carcinoma invasion by inhibiting proliferation, migration, and extracellular matrix degradation and that the ERK/MAPK pathway is a target of MALT1 and further suggests a role as a suppressor of carcinoma progression. PMID:26701346

  15. IGF-1 protects tubular epithelial cells during injury via activation of ERK/MAPK signaling pathway

    PubMed Central

    Wu, Zengbin; Yu, Yang; Niu, Lei; Fei, Aihua; Pan, Shuming

    2016-01-01

    Injury of renal tubular epithelial cells can induce acute renal failure and obstructive nephropathy. Previous studies have shown that administration of insulin-like growth factor-1 (IGF-1) ameliorates the renal injury in a mouse unilateral ureteral obstruction (UUO) model, whereas the underlying mechanisms are not completely understood. Here, we addressed this question. We found that the administration of IGF-1 significantly reduced the severity of the renal fibrosis in UUO. By analyzing purified renal epithelial cells, we found that IGF-1 significantly reduced the apoptotic cell death of renal epithelial cells, seemingly through upregulation of anti-apoptotic protein Bcl-2, at protein but not mRNA level. Bioinformatics analyses and luciferase-reporter assay showed that miR-429 targeted the 3′-UTR of Bcl-2 mRNA to inhibit its protein translation in renal epithelial cells. Moreover, IGF-1 suppressed miR-429 to increase Bcl-2 in renal epithelial cells to improve survival after UUO. Furthermore, inhibition of ERK/MAPK signaling pathway in renal epithelial cells abolished the suppressive effects of IGF-1 on miR-429 activation, and then the enhanced effects on Bcl-2 in UUO. Thus, our data suggest that IGF-1 may protect renal tubular epithelial cells via activation of ERK/MAPK signaling pathway during renal injury. PMID:27301852

  16. Differential Activation of Mitogen-Activated Protein Kinases, ERK 1/2, p38(MAPK) and JNK p54/p46 During Postnatal Development of Rat Hippocampus.

    PubMed

    Costa, Ana Paula; Lopes, Mark William; Rieger, Débora K; Barbosa, Sabrina Giovana Rocha; Gonçalves, Filipe Marques; Xikota, João Carlos; Walz, Roger; Leal, Rodrigo B

    2016-05-01

    Mitogen-activated protein kinases (MAPKs) are a group of serine-threonine kinases, including p38(MAPK), ERK 1/2 and JNK p54/p46, activated by phosphorylation in response to extracellular stimuli. The early postnatal period is characterized by significant changes in brain structure as well as intracellular signaling. In the hippocampus MAPKs have been involved in the modulation of development and neural plasticity. However, the temporal profile of MAPK activation throughout the early postnatal development is incomplete. An understanding of this profile is important since slight changes in the activity of these enzymes, in response to environmental stress in specific developmental windows, might alter the course of development. The present study was undertaken to investigate the hippocampal differential activation of MAPK during postnatal period. MAPK activation and total content were evaluated by Western blotting of hippocampal tissue obtained from male Wistar rats at postnatal days (P) 1, 4, 7, 10, 14, 21, 30 and 60. The total content and phosphorylation of each MAPK was expressed as mean ± SEM and then calculates as a percentile compared to P1 (set at 100 %). The results showed: (1) phosphorylation peaks of p38(MAPK) at PN4 (p = 0.036) and PN10 to PN60; (2) phosphorylation of ERK1 and ERK2 were increased with age (ERK1 p = 0.0000005 and ERK2 p = 0.003); (3) phosphorylation profile of JNK p54/p46 was not changed during the period analyzed (JNKp56 p = 0.716 and JNKp46 p = 0.192). Therefore, the activity profile of ERK 1/2 and p38(MAPK) during postnatal development of rat hippocampus are differentially regulated. Our results demonstrate that ERK 1/2 and p38(MAPK) are dynamically regulated during postnatal neurodevelopment, suggesting temporal correlation of MAPK activity with critical periods when programmed cell death and synaptogenesis are occurring. This suggests an important role for these MAPKs in postnatal development of rat hippocampus. PMID

  17. p38 MAPK Is Activated but Does Not Play a Key Role during Apoptosis Induction by Saturated Fatty Acid in Human Pancreatic β-Cells

    PubMed Central

    Šrámek, Jan; Němcová-Fürstová, Vlasta; Balušíková, Kamila; Daniel, Petr; Jelínek, Michael; James, Roger F.; Kovář, Jan

    2016-01-01

    Saturated stearic acid (SA) induces apoptosis in the human pancreatic β-cells NES2Y. However, the molecular mechanisms involved are unclear. We showed that apoptosis-inducing concentrations of SA activate the p38 MAPK signaling pathway in these cells. Therefore, we tested the role of p38 MAPK signaling pathway activation in apoptosis induction by SA in NES2Y cells. Crosstalk between p38 MAPK pathway activation and accompanying ERK pathway inhibition after SA application was also tested. The inhibition of p38 MAPK expression by siRNA silencing resulted in a decrease in MAPKAPK-2 activation after SA application, but it had no significant effect on cell viability or the level of phosphorylated ERK pathway members. The inhibition of p38 MAPK activity by the specific inhibitor SB202190 resulted in inhibition of MAPKAPK-2 activation and noticeable activation of ERK pathway members after SA treatment but in no significant effect on cell viability. p38 MAPK overexpression by plasmid transfection produced an increase in MAPKAPK-2 activation after SA exposure but no significant influence on cell viability or ERK pathway activation. The activation of p38 MAPK by the specific activator anisomycin resulted in significant activation of MAPKAPK-2. Concerning the effect on cell viability, application of the activator led to apoptosis induction similar to application of SA (PARP cleavage and caspase-7, -8, and -9 activation) and in inhibition of ERK pathway members. We demonstrated that apoptosis-inducing concentrations of SA activate the p38 MAPK signaling pathway and that this activation could be involved in apoptosis induction by SA in the human pancreatic β-cells NES2Y. However, this involvement does not seem to play a key role. Crosstalk between p38 MAPK pathway activation and ERK pathway inhibition in NES2Y cells seems likely. Thus, the ERK pathway inhibition by p38 MAPK activation does not also seem to be essential for SA-induced apoptosis. PMID:26861294

  18. MEK1-independent activation of MAPK and MEK1-dependent activation of p70 S6 kinase by stem cell factor (SCF) in ovarian cancer cells

    SciTech Connect

    Liu, Lian; Zhang, Xin; Du, Chao; Zhang, Xiaoning; Hou, Nan; Zhao, Di; Sun, Jianzhi; Li, Li; Wang, Xiuwen; Ma, Chunhong

    2009-05-01

    We discovered a stem cell factor (SCF)-triggered, MEK1-independent, and PI3K-dependent MAPK activation pathway in the Kit-expressing ovarian cancer cell line HEY. When we knocked down MEK1 with RNA interference (RNAi) to study the function of MEK1 on the proliferation and survival of ovarian cancer cells, we found that impaired cell growth still occurred after MEK1 expression had been suppressed, although MAPK activation remained intact. This suggests that there is MEK1-independent activation of MAPK in the SCF-induced ovarian cancer cell growth process, and that MEK1 still plays a crucial role in maintaining the malignant properties of ovarian cancer cells even when it fails to activate MAPK as expected.

  19. RAS/MAPK Activation Drives Resistance to Smo Inhibition, Metastasis, and Tumor Evolution in Shh Pathway-Dependent Tumors.

    PubMed

    Zhao, Xuesong; Ponomaryov, Tatyana; Ornell, Kimberly J; Zhou, Pengcheng; Dabral, Sukriti K; Pak, Ekaterina; Li, Wei; Atwood, Scott X; Whitson, Ramon J; Chang, Anne Lynn S; Li, Jiang; Oro, Anthony E; Chan, Jennifer A; Kelleher, Joseph F; Segal, Rosalind A

    2015-09-01

    Aberrant Shh signaling promotes tumor growth in diverse cancers. The importance of Shh signaling is particularly evident in medulloblastoma and basal cell carcinoma (BCC), where inhibitors targeting the Shh pathway component Smoothened (Smo) show great therapeutic promise. However, the emergence of drug resistance limits long-term efficacy, and the mechanisms of resistance remain poorly understood. Using new medulloblastoma models, we identify two distinct paradigms of resistance to Smo inhibition. Sufu mutations lead to maintenance of the Shh pathway in the presence of Smo inhibitors. Alternatively activation of the RAS-MAPK pathway circumvents Shh pathway dependency, drives tumor growth, and enhances metastatic behavior. Strikingly, in BCC patients treated with Smo inhibitor, squamous cell cancers with RAS/MAPK activation emerged from the antecedent BCC tumors. Together, these findings reveal a critical role of the RAS-MAPK pathway in drug resistance and tumor evolution of Shh pathway-dependent tumors. PMID:26130651

  20. RAS/MAPK activation drives resistance to Smo inhibition, metastasis and tumor evolution in Shh pathway-dependent tumors

    PubMed Central

    Zhao, Xuesong; Ponomaryov, Tatyana; Ornell, Kimberly J.; Zhou, Pengcheng; Dabral, Sukriti K.; Pak, Ekaterina; Li, Wei; Atwood, Scott X.; Whitson, Ramon J.; Chang, Anne Lynn S.; Li, Jiang; Oro, Anthony E.; Chan, Jennifer A.; Kelleher, Joseph F.; Segal, Rosalind A.

    2015-01-01

    Aberrant Shh signaling promotes tumor growth in diverse cancers. The importance of Shh signaling is particularly evident in medulloblastoma and basal cell carcinoma (BCC), where inhibitors targeting the Shh pathway component Smoothened (Smo) show great therapeutic promise. However, the emergence of drug resistance limits long-term efficacy and the mechanisms of resistance remain poorly understood. Using new medulloblastoma models, we identify two distinct paradigms of resistance to Smo inhibition. Sufu mutations lead to maintenance of the Shh pathway in the presence of Smo inhibitors. Alternatively activation of the RAS/MAPK pathway circumvents Shh pathway-dependency, drives tumor growth and enhances metastatic behavior. Strikingly, in BCC patients treated with Smo inhibitor, squamous cell cancers with RAS/MAPK activation emerged from the antecedent BCC tumors. Together these findings reveal a critical role of RAS/MAPK pathway in drug resistance and tumor evolution of Shh pathway-dependent tumors. PMID:26130651

  1. Michael addition of dehydroalanine-containing MAPK peptides to catalytic lysine inhibits the activity of phosphothreonine lyase.

    PubMed

    Zhang, Yuan; Yang, Ru; Huang, Juan; Liang, Qiujin; Guo, Yanmin; Bian, Weixiang; Luo, Lingfei; Li, Hongtao

    2015-11-30

    The phosphothreonine lyases OspF and SpvC irreversibly inactivate host dual-phosphorylated mitogen-activated protein kinases (MAPKs) [pThr-X-pTyr motif] through β-elimination. We found that dual-phosphorylated (pSer-X-pTyr) MAPK substrate peptides and their resulting catalytic products cross-link to OspF and SpvC. Mass spectrometry results revealed that these linkages form between lysine, which acts as a general base, and dehydroalanine (Dha) on catalytic products. The nucleophilic addition efficiency is dependent on the K136 residue being in a deprotonated state. Peptide cross-linking inhibits the activity of SpvC and blocks the inactivation of MAPK signaling by SpvC. Small compounds mimicking these sequences may act as phosphothreonine lyase inhibitors. PMID:26519561

  2. REX-1 Expression and p38 MAPK Activation Status Can Determine Proliferation/Differentiation Fates in Human Mesenchymal Stem Cells

    PubMed Central

    Jung, Ji-Won; Kang, Soo-Kyung; Kang, Kyung-Sun

    2010-01-01

    Background REX1/ZFP42 is a well-known embryonic stem cell (ESC) marker. However, the role of REX1, itself, is relatively unknown because the function of REX1 has only been reported in the differentiation of ESCs via STAT signaling pathways. Human mesenchymal stem cells (hMSCs) isolated from young tissues and cancer cells express REX1. Methodology/Principal Finding Human umbilical cord blood-derived MSCs (hUCB-MSCs) and adipose tissue-derived MSCs (hAD-MSCs) strongly express REX1 and have a lower activation status of p38 MAPK, but bone marrow-derived MSCs (hBM-MSCs) have weak REX1 expression and higher activation of p38 MAPK. These results indicated that REX1 expression in hMSCs was positively correlated with proliferation rates but inversely correlated with the phosphorylation of p38 MAPK. In hUCB-MSCs, the roles of REX1 and p38 MAPK were investigated, and a knockdown study was performed using a lentiviral vector-based small hairpin RNA (shRNA). After REX1 knockdown, decreased cell proliferation was observed. In REX1 knocked-down hUCB-MSCs, the osteogenic differentiation ability deteriorated, but the adipogenic potential increased or was similar to that observed in the controls. The phosphorylation of p38 MAPK in hUCB-MSCs significantly increased after REX1 knockdown. After p38 MAPK inhibitor treatment, the cell growth in REX1 knocked-down hUCB-MSCs almost recovered, and the suppressed expression levels of CDK2 and CCND1 were also restored. The expression of MKK3, an upstream regulator of p38 MAPK, significantly increased in REX1 knocked-down hUCB-MSCs. The direct binding of REX1 to the MKK3 gene was confirmed by a chromatin immunoprecipitation (ChIP) assay. Conclusions/Significance These findings showed that REX1 regulates the proliferation/differentiation of hMSCs through the suppression of p38 MAPK signaling via the direct suppression of MKK3. Therefore, p38 MAPK and REX-1 status can determine the cell fate of adult stem cells (ASCs). These results were the

  3. A new water soluble MAPK activator exerts antitumor activity in melanoma cells resistant to the BRAF inhibitor vemurafenib.

    PubMed

    Graziani, Grazia; Artuso, Simona; De Luca, Anastasia; Muzi, Alessia; Rotili, Dante; Scimeca, Manuel; Atzori, Maria Grazia; Ceci, Claudia; Mai, Antonello; Leonetti, Carlo; Levati, Lauretta; Bonanno, Elena; Tentori, Lucio; Caccuri, Anna Maria

    2015-05-01

    Recovery of mitogen activated protein kinase (MAPK) or activation of alternative pathways, such as the PI3K/AKT/mTOR, are involved in acquired resistance to BRAF inhibitors which represent the first-line treatment of BRAF-mutated metastatic melanoma. We recently demonstrated that 6-((7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)thio)hexan-1-ol (NBDHEX) and its water soluble analog 2-(2-(2-((7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)thio)ethoxy)ethoxy)ethanol (MC3181) trigger apoptosis in BRAF V600E mutated melanoma cells through activation of the MAPK c-Jun N-terminal kinase (JNK). Herein, we investigated whether NBDHEX and MC3181 might exert antitumor activity against BRAF V600E mutated human melanoma cells rendered resistant to the BRAF inhibitor vemurafenib. To this aim we generated a subline of A375 melanoma resistant in vitro and in vivo to vemurafenib (A375-VR8) and characterized by NRAS G13R mutation, high basal levels of CRAF protein and phospho-activation of AKT. In these cells ERK phosphorylation was not significantly down-modulated by vemurafenib concentrations capable of abrogating ERK phosphorylation in sensitive A375 cells. Both NBDHEX and MC3181 induced marked antiproliferative and apoptotic effects in A375-VR8 cells and, at equitoxic concentrations, caused a strong phosphorylation of JNK, p38, and of the downstream mediators of apoptosis ATF2 and p53. Drug treatment further increased ERK phosphorylation, which was required for the cellular response to the NBD derivatives, as apoptosis was antagonized by the ERK inhibitor FR180204. Finally, in vivo administration of MC3181 provoked JNK activation at the tumor site and markedly reduced A375-VR8 growth. These evidences strongly suggest that the activation of multiple pro-apoptotic MAPK pathways by MC3181 might represent a new strategy for the treatment of melanoma resistant to BRAF inhibitors. PMID:25795251

  4. Variants of the yeast MAPK Mpk1 are fully functional independently of activation loop phosphorylation.

    PubMed

    Goshen-Lago, Tal; Goldberg-Carp, Anat; Melamed, Dganit; Darlyuk-Saadon, Ilona; Bai, Chen; Ahn, Natalie G; Admon, Arie; Engelberg, David

    2016-09-01

    MAP kinases of the ERK family are conserved from yeast to humans. Their catalytic activity is dependent on dual phosphorylation of their activation loop's TEY motif, catalyzed by MAPK kinases (MEKs). Here we studied variants of Mpk1, a yeast orthologue of Erk, which is essential for cell wall integrity. Cells lacking MPK1, or the genes encoding the relevant MEKs, MKK1 and MKK2, do not proliferate under cell wall stress, imposed, for example, by caffeine. Mutants of Mpk1, Mpk1(Y268C) and Mpk1(Y268A), function independently of Mkk1 and Mkk2. We show that these variants are phosphorylated at their activation loop in mkk1∆mkk2∆ and mkk1∆mkk2∆pbs2∆ste7∆ cells, suggesting that they autophosphorylate. However, strikingly, when Y268C/A mutations were combined with the kinase-dead mutation, K54R, or mutations at the TEY motif, T190A+Y192F, the resulting proteins still allowed mkk1∆mkk2∆ cells to proliferate under caffeine stress. Mutating the equivalent residue, Tyr-280/Tyr-261, in Erk1/Erk2 significantly impaired Erk1/2's catalytic activity. This study describes the first case in which a MAPK, Erk/Mpk1, imposes a phenotype via a mechanism that is independent of TEY phosphorylation and an unusual case in which an equivalent mutation in a highly conserved domain of yeast and mammalian Erks causes an opposite effect. PMID:27413009

  5. R-Ras inhibits VEGF-induced p38MAPK activation and HSP27 phosphorylation in endothelial cells

    PubMed Central

    Sawada, Junko; Li, Fangfei; Komatsu, Masanobu

    2016-01-01

    R-Ras is a Ras family small GTPase highly expressed in mature functional blood vessels in normal tissues. It inhibits pathological angiogenesis and promotes vessel maturation and stabilization. Previous studies suggest that R-Ras affects cellular signaling in endothelial cells, pericytes, and smooth muscle cells to regulate vessel formation and remodeling in adult tissues. R-Ras suppresses VEGF-induced endothelial permeability and vessel sprouting while promoting normalization of pathologically developing vessels in mice. R-Ras attenuates VEGF receptor-2 (VEGFR2) activation by inhibiting internalization of the receptor upon VEGF ligand binding, leading to significant reduction of VEGFR2 autophosphorylation. Here, we show that R-Ras strongly suppresses VEGF-dependent activation of stress-activated protein kinase-2/p38 mitogen-activated protein kinase (SAPK2/p38MAPK) and phosphorylation of downstream heat shock protein 27 (HSP27), a regulator of actin cytoskeleton organization, in endothelial cells. The suppression of p38MAPK activation and HSP27 phosphorylation by R-Ras concurred with altered actin cytoskeleton architecture, reduced membrane protrusion, and inhibition of endothelial cell migration toward VEGF. Silencing of endogenous R-Ras by RNAi increased membrane protrusion and cell migration stimulated by VEGF, and these effects were offset by p38MAPK inhibitor SB203580. These results suggest that R-Ras regulates angiogenic activities of endothelial cells in part via inhibition of the p38MAPK-HSP27 axis of VEGF signaling. PMID:27029009

  6. Small Molecule APY606 Displays Extensive Antitumor Activity in Pancreatic Cancer via Impairing Ras-MAPK Signaling

    PubMed Central

    Guo, Na; Liu, Zuojia; Zhao, Wenjing; Wang, Erkang; Wang, Jin

    2016-01-01

    Pancreatic cancer has been found with abnormal expression or mutation in Ras proteins. Oncogenic Ras activation exploits their extensive signaling reach to affect multiple cellular processes, in which the mitogen-activated protein kinase (MAPK) signaling exerts important roles in tumorigenesis. Therapies targeted Ras are thus of major benefit for pancreatic cancer. Although small molecule APY606 has been successfully picked out by virtual drug screening based on Ras target receptor, its in-depth mechanism remains to be elucidated. We herein assessed the antitumor activity of APY606 against human pancreatic cancer Capan-1 and SW1990 cell lines and explored the effect of Ras-MAPK and apoptosis-related signaling pathway on the activity of APY606. APY606 treatment resulted in a dose- and time-dependent inhibition of cancer cell viability. Additionally, APY606 exhibited strong antitumor activity, as evidenced not only by reduction in tumor cell invasion, migration and mitochondrial membrane potential but also by alteration in several apoptotic indexes. Furthermore, APY606 treatment directly inhibited Ras-GTP and the downstream activation of MAPK, which resulted in the down-regulation of anti-apoptotic protein Bcl-2, leading to the up-regulation of mitochondrial apoptosis pathway-related proteins (Bax, cytosolic Cytochrome c and Caspase 3) and of cyclin-dependent kinase 2 and Cyclin A, E. These data suggest that impairing Ras-MAPK signaling is a novel mechanism of action for APY606 during therapeutic intervention in pancreatic cancer. PMID:27223122

  7. Small Molecule APY606 Displays Extensive Antitumor Activity in Pancreatic Cancer via Impairing Ras-MAPK Signaling.

    PubMed

    Guo, Na; Liu, Zuojia; Zhao, Wenjing; Wang, Erkang; Wang, Jin

    2016-01-01

    Pancreatic cancer has been found with abnormal expression or mutation in Ras proteins. Oncogenic Ras activation exploits their extensive signaling reach to affect multiple cellular processes, in which the mitogen-activated protein kinase (MAPK) signaling exerts important roles in tumorigenesis. Therapies targeted Ras are thus of major benefit for pancreatic cancer. Although small molecule APY606 has been successfully picked out by virtual drug screening based on Ras target receptor, its in-depth mechanism remains to be elucidated. We herein assessed the antitumor activity of APY606 against human pancreatic cancer Capan-1 and SW1990 cell lines and explored the effect of Ras-MAPK and apoptosis-related signaling pathway on the activity of APY606. APY606 treatment resulted in a dose- and time-dependent inhibition of cancer cell viability. Additionally, APY606 exhibited strong antitumor activity, as evidenced not only by reduction in tumor cell invasion, migration and mitochondrial membrane potential but also by alteration in several apoptotic indexes. Furthermore, APY606 treatment directly inhibited Ras-GTP and the downstream activation of MAPK, which resulted in the down-regulation of anti-apoptotic protein Bcl-2, leading to the up-regulation of mitochondrial apoptosis pathway-related proteins (Bax, cytosolic Cytochrome c and Caspase 3) and of cyclin-dependent kinase 2 and Cyclin A, E. These data suggest that impairing Ras-MAPK signaling is a novel mechanism of action for APY606 during therapeutic intervention in pancreatic cancer. PMID:27223122

  8. R-Ras Inhibits VEGF-Induced p38MAPK Activation and HSP27 Phosphorylation in Endothelial Cells.

    PubMed

    Sawada, Junko; Li, Fangfei; Komatsu, Masanobu

    2015-01-01

    R-Ras is a Ras family small GTPase that is highly expressed in mature functional blood vessels in normal tissues. It inhibits pathological angiogenesis and promotes vessel maturation and stabilization. Previous studies suggest that R-Ras affects cellular signaling in endothelial cells, pericytes and smooth-muscle cells to regulate vessel formation and remodeling in adult tissues. R-Ras suppresses VEGF-induced endothelial permeability and vessel sprouting while promoting normalization of pathologically developing vessels in mice. It attenuates VEGF receptor-2 (VEGFR2) activation by inhibiting internalization of the receptor upon VEGF ligand binding, leading to significant reduction of VEGFR2 autophosphorylation. Here, we show that R-Ras strongly suppresses the VEGF-dependent activation of stress-activated protein kinase-2/p38 mitogen-activated protein kinase (SAPK2/p38MAPK) and the phosphorylation of downstream heat-shock protein 27 (HSP27), a regulator of actin cytoskeleton organization, in endothelial cells. The suppression of p38MAPK activation and HSP27 phosphorylation by R-Ras concurred with altered actin cytoskeleton architecture, reduced membrane protrusion and inhibition of endothelial cell migration toward VEGF. Silencing of endogenous R-Ras by RNA interference increased membrane protrusion and cell migration stimulated by VEGF, and these effects were offset by p38MAPK inhibitor SB203580. These results suggest that R-Ras regulates angiogenic activities of endothelial cells in part via inhibition of the p38MAPK-HSP27 axis of VEGF signaling. PMID:27029009

  9. Quantitative cell signalling analysis reveals down-regulation of MAPK pathway activation in colorectal cancer.

    PubMed

    Gulmann, Christian; Sheehan, Katherine M; Conroy, Ronán M; Wulfkuhle, Julia D; Espina, Virginia; Mullarkey, Michelle J; Kay, Elaine W; Liotta, Lance A; Petricoin, Emanuel F

    2009-08-01

    Mitogen-activated protein kinases (MAPK) are considered to play significant roles in colonic carcinogenesis and kinase inhibitor therapy has been proposed as a potential tool in the treatment of this disease. Reverse-phase microarray assays using phospho-specific antibodies can directly measure levels of phosphorylated protein isoforms. In the current study, samples from 35 cases of untreated colorectal cancer colectomies were laser capture-microdissected to isolate epithelium and stroma from cancer as well as normal (i.e. uninvolved) mucosa. Lysates generated from these four tissue types were spotted onto reverse-phase protein microarrays and probed with a panel of antibodies to ERK, p-ERK, p38, p-p38, p-JNK, MEK and p-MEK. Whereas total protein levels were unchanged, or slightly elevated (p38, p = 0.0025) in cancers, activated isoforms, including p-ERK, p-p38 and p-JNK, were decreased two- to four-fold in cancers compared with uninvolved mucosa (p < 0.0023 in all cases except for p-JNK in epithelium, where decrement was non-significant). This was backed up by western blotting. Dukes' stage B and C cancers displayed lower p-ERK and p-p38 expression than Dukes' stage A cancers, although this was not statistically significant. It is concluded that MAPK activity may be down-regulated in colorectal cancer and that further exploration of inhibitory therapy in this system should be carefully evaluated if this finding is confirmed in larger series. PMID:19396842

  10. 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

  11. TNF-α-induced p38MAPK activation regulates TRPA1 and TRPV4 activity in odontoblast-like cells.

    PubMed

    El Karim, Ikhlas; McCrudden, Maeliosa T C; Linden, Gerard J; Abdullah, Hanniah; Curtis, Timothy M; McGahon, Mary; About, Imad; Irwin, Christopher; Lundy, Fionnuala T

    2015-11-01

    The transient receptor potential (TRP) channels are unique cellular sensors that are widely expressed in many neuronal and nonneuronal cells. Among the TRP family members, TRPA1 and TRPV4 are emerging as candidate mechanosensitive channels that play a pivotal role in inflammatory pain and mechanical hyperalgesia. Odontoblasts are nonneuronal cells that possess many of the features of mechanosensitive cells and mediate important defense and sensory functions. However, the effect of inflammation on the activity of the odontoblast's mechanosensitive channels remains unknown. By using immunohistochemistry and calcium microfluorimetry, we showed that odontoblast-like cells express TRPA1 and TRPV4 and that these channels were activated by hypotonicity-induced membrane stretch. Short treatment of odontoblast-like cells with tumor necrosis factor (TNF)-α enhanced TRPA1 and TRPV4 responses to their chemical agonists and membrane stretch. This enhanced channel activity was accompanied by phospho-p38 mitogen-activated protein kinase (MAPK) expression. Treatment of cells with the p38 inhibitor SB202190 reduced TNF-α effects, suggesting modulation of channel activity via p38 MAPK. In addition, TNF-α treatment also resulted in an up-regulation of TRPA1 expression but down-regulation of TRPV4. Unlike TRPV4, enhanced TRPA1 expression was also evident in dental pulp of carious compared with noncarious teeth. SB202190 treatment significantly reduced TNF-α-induced TRPA1 expression, suggesting a role for p38 MAPK signaling in modulating both the transcriptional and non-transcriptional regulation of TRP channels in odontoblasts. PMID:26358221

  12. Hypoxia differentially regulates the mitogen- and stress-activated protein kinases. Role of Ca2+/CaM in the activation of MAPK and p38 gamma.

    PubMed

    Conrad, P W; Millhorn, D E; Beitner-Johnson, D

    2000-01-01

    Hypoxic/ischemic trauma is a primary factor in the pathology of various vascular, pulmonary, and cerebral disease states. Yet, the signaling mechanisms by which cells respond and adapt to changes in oxygen levels are not clearly established. The effects of hypoxia on the stress- and mitogen-activated protein kinase (SAPK and MAPK) signaling pathways were studied in PC12 cells. Exposure to moderate hypoxia (5% O2) was found to progressively stimulate phosphorylation and activation of p38 gamma in particular, and also p38 alpha, two isoforms of the p38 family of stress-activated protein kinases. In contrast, hypoxia had no effect on enzyme activity of p38 beta, p38 beta 2, p38 delta, or on JNK, another stress-activated protein kinase. Prolonged hypoxia also induced phosphorylation and activation of p42/p44 MAPK, although this activation was modest when compared to NGF and UV-induced activation. We further showed that activation of p38 gamma and MAPK during hypoxia requires calcium, as treatment with Ca(2+)-free media or the calmodulin antagonist, W13, blocked the activation of p38 gamma and MAPK, respectively. These studies demonstrate that an extremely typical physiological stress (hypoxia) causes selective activation of specific elements of the SAPKs and MAPKs, and identifies Ca+2/CaM as a critical upstream activator. PMID:10849670

  13. Bcl-3 Expression Promotes Cell Survival following Interleukin-4 Deprivation and Is Controlled by AP1 and AP1-Like Transcription Factors

    PubMed Central

    Rebollo, Angelita; Dumoutier, Laure; Renauld, Jean-Christophe; Zaballos, Angel; Ayllón, Verónica; Martínez-A., Carlos

    2000-01-01

    We have analyzed the interleukin-4 (IL-4)-triggered mechanisms implicated in cell survival and show here that IL-4 deprivation induces apoptotic cell death but does not modulate Bcl-2 or Bcl-x expression. Since Bcl-x expression is insufficient to ensure cell survival in the absence of IL-4, we speculate that additional molecules replace the antiapoptotic role of Bcl-2 and Bcl-x in an alternative IL-4-triggered pathway. Cell death is associated with Bcl-3 downregulation and Bcl-3 expression blocks IL-4 deprivation-induced apoptosis, suggesting that Bcl-3 acts as a survival factor in the absence of growth factor. To characterize the IL-4-induced regulation of murine Bcl-3 expression, we cloned the promoter of this gene. Sequencing of the promoter showed no TATA box element but did reveal binding sites for AP1, AP1-like, and SP1 transcription factors. Retardation gels showed that IL-4 specifically induces AP1 and AP1-like binding activity and that mutation of these binding sites abolishes the IL-4-induced Bcl-3 promoter activity, suggesting that these transcription factors are important in Bcl-3 promoter transactivation. IL-4 deprivation induces downregulation of Jun expression and upregulation of Fos expression, both of which are proteins involved in the formation of AP1 and AP1-like transcription factors. Overexpression of Jun family proteins transactivates the promoter and restores Bcl-3 expression in the absence of IL-4 stimulation. Taken together, these data describe a new biological role for Bcl-3 and define the regulatory pathway implicated in Bcl-3 expression. PMID:10779330

  14. CHIP promotes thyroid cancer proliferation via activation of the MAPK and AKT pathways.

    PubMed

    Zhang, Li; Liu, Lianyong; He, Xiaohua; Shen, Yunling; Liu, Xuerong; Wei, Jing; Yu, Fang; Tian, Jianqing

    2016-08-26

    The carboxyl terminus of Hsp70-interacting protein (CHIP) is a U box-type ubiquitin ligase that plays crucial roles in various biological processes, including tumor progression. To date, the functional mechanism of CHIP in thyroid cancer remains unknown. Here, we obtained evidence of upregulation of CHIP in thyroid cancer tissues and cell lines. CHIP overexpression markedly enhanced thyroid cancer cell viability and colony formation in vitro and accelerated tumor growth in vivo. Conversely, CHIP knockdown impaired cell proliferation and tumor growth. Notably, CHIP promoted cell growth through activation of MAPK and AKT pathways, subsequently decreasing p27 and increasing cyclin D1 and p-FOXO3a expression. Our findings collectively indicate that CHIP functions as an oncogene in thyroid cancer, and is therefore a potential therapeutic target for this disease. PMID:27342662

  15. MAPK Activation Is Essential for Waddlia chondrophila Induced CXCL8 Expression in Human Epithelial Cells

    PubMed Central

    Storrie, Skye; Longbottom, David; Barlow, Peter G.; Wheelhouse, Nick

    2016-01-01

    Background Waddlia chondrophila (W. chondrophila) is an emerging agent of respiratory and reproductive disease in humans and cattle. The organism is a member of the order Chlamydiales, and shares many similarities at the genome level and in growth studies with other well-characterised zoonotic chlamydial agents, such as Chlamydia abortus (C. abortus). The current study investigated the growth characteristics and innate immune responses of human and ruminant epithelial cells in response to infection with W. chondrophila. Methods Human epithelial cells (HEp2) were infected with W. chondrophila for 24h. CXCL8 release was significantly elevated in each of the cell lines by active-infection with live W. chondrophila, but not by exposure to UV-killed organisms. Inhibition of either p38 or p42/44 MAPK significantly inhibited the stimulation of CXCL8 release in each of the cell lines. To determine the pattern recognition receptor through which CXCL8 release was stimulated, wild-type HEK293 cells which express no TLR2, TLR4, NOD2 and only negligible NOD1 were infected with live organisms. A significant increase in CXCL8 was observed. Conclusions/Significance W. chondrophila actively infects and replicates within both human and ruminant epithelial cells stimulating CXCL8 release. Release of CXCL8 is significantly inhibited by inhibition of either p38 or p42/44 MAPK indicating a role for this pathway in the innate immune response to W. chondrophila infection. W. chondrophila stimulation of CXCL8 secretion in HEK293 cells indicates that TLR2, TLR4, NOD2 and NOD1 receptors are not essential to the innate immune response to infection. PMID:27002636

  16. The p38alpha/beta MAPK functions as a molecular switch to activate the quiescent satellite cell.

    PubMed

    Jones, Nathan C; Tyner, Kristina J; Nibarger, Lisa; Stanley, Heather M; Cornelison, Dawn D W; Fedorov, Yuri V; Olwin, Bradley B

    2005-04-11

    Somatic stem cells cycle slowly or remain quiescent until required for tissue repair and maintenance. Upon muscle injury, stem cells that lie between the muscle fiber and basal lamina (satellite cells) are activated, proliferate, and eventually differentiate to repair the damaged muscle. Satellite cells in healthy muscle are quiescent, do not express MyoD family transcription factors or cell cycle regulatory genes and are insulated from the surrounding environment. Here, we report that the p38alpha/beta family of mitogen-activated protein kinases (MAPKs) reversibly regulates the quiescent state of the skeletal muscle satellite cell. Inhibition of p38alpha/beta MAPKs (a) promotes exit from the cell cycle, (b) prevents differentiation, and (c) insulates the cell from most external stimuli allowing the satellite cell to maintain a quiescent state. Activation of satellite cells and p38alpha/beta MAPKs occurs concomitantly, providing further support that these MAPKs function as a molecular switch for satellite cell activation. PMID:15824134

  17. Increases in cAMP, MAPK Activity and CREB Phosphorylation during REM Sleep: Implications for REM Sleep and Memory Consolidation

    PubMed Central

    Luo, Jie; Phan, Trongha X.; Yang, Yimei; Garelick, Michael G.; Storm, Daniel R.

    2013-01-01

    The cyclic adenosine monophosphate (cAMP), mitogen-activated protein kinase (MAPK) and cAMP response element-binding protein (CREB) transcriptional pathway is required for consolidation of hippocampus-dependent memory. In mice, this pathway undergoes a circadian oscillation required for memory persistence that reaches a peak during the daytime. Since mice exhibit polyphasic sleep patterns during the day, this suggested the interesting possibility that cAMP, MAPK activity and CREB phosphorylation may be elevated during sleep. Here, we report that cAMP, phospho-p44/42 MAPK and phospho-CREB are higher in rapid eye movement (REM) sleep compared to awake mice but are not elevated in non-rapid eye movement (NREM) sleep. This peak of activity during REM sleep does not occur in mice lacking calmodulin-stimulated adenylyl cyclases, a mouse strain that learns but cannot consolidate hippocampus-dependent memory. We conclude that a preferential increase in cAMP, MAPK activity and CREB phosphorylation during REM sleep may contribute to hippocampus-dependent memory consolidation. PMID:23575844

  18. Increases in cAMP, MAPK activity, and CREB phosphorylation during REM sleep: implications for REM sleep and memory consolidation.

    PubMed

    Luo, Jie; Phan, Trongha X; Yang, Yimei; Garelick, Michael G; Storm, Daniel R

    2013-04-10

    The cyclic adenosine monophosphate (cAMP), mitogen-activated protein kinase (MAPK), and cAMP response element-binding protein (CREB) transcriptional pathway is required for consolidation of hippocampus-dependent memory. In mice, this pathway undergoes a circadian oscillation required for memory persistence that reaches a peak during the daytime. Because mice exhibit polyphasic sleep patterns during the day, this suggested the interesting possibility that cAMP, MAPK activity, and CREB phosphorylation may be elevated during sleep. Here, we report that cAMP, phospho-p44/42 MAPK, and phospho-CREB are higher in rapid eye movement (REM) sleep compared with awake mice but are not elevated in non-REM sleep. This peak of activity during REM sleep does not occur in mice lacking calmodulin-stimulated adenylyl cyclases, a mouse strain that learns but cannot consolidate hippocampus-dependent memory. We conclude that a preferential increase in cAMP, MAPK activity, and CREB phosphorylation during REM sleep may contribute to hippocampus-dependent memory consolidation. PMID:23575844

  19. CONTRIBUTION OF INSPIRATORY FLOW TO ACTIVATION OF EGFR, RAS, MAPK, ATF-2 AND C-JUN DURING LUNG STRETCH

    EPA Science Inventory

    Contribution of Inspiratory Flow to Activation of EGFR, Ras, MAPK, ATF-2 and c-Jun during Lung Stretch

    R. Silbajoris 1, Z. Li 2, J. M. Samet 1 and Y. C. Huang 1. 1 NHEERL, ORD, US EPA, RTP, NC and 2 CEMALB, UNC-CH, Chapel Hill, NC .

    Mechanical ventilation with larg...

  20. Trimethyltin-Induced Microglial Activation via NADPH Oxidase and MAPKs Pathway in BV-2 Microglial Cells

    PubMed Central

    Kim, Da Jung; Kim, Yong Sik

    2015-01-01

    Trimethyltin (TMT) is known as a potent neurotoxicant that causes neuronal cell death and neuroinflammation, particularly in the hippocampus. Microglial activation is one of the prominent pathological features of TMT neurotoxicity. Nevertheless, it remains unclear how microglial activation occurs in TMT intoxication. In this study, we aimed to investigate the signaling pathways in TMT-induced microglial activation using BV-2 murine microglial cells. Our results revealed that TMT generates reactive oxygen species (ROS) and increases the expression of CD11b and nuclear factor-κB- (NF-κB-) mediated nitric oxide (NO) and tumor necrosis factor- (TNF-) α in BV-2 cells. We also observed that NF-κB activation was controlled by p38 and JNK phosphorylation. Moreover, TMT-induced ROS generation occurred via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in BV-2 cells. Interestingly, treatment with the NADPH oxidase inhibitor apocynin significantly suppressed p38 and JNK phosphorylation and NF-κB activation and ultimately the production of proinflammatory mediators upon TMT exposure. These findings indicate that NADPH oxidase-dependent ROS generation activated p38 and JNK mitogen-activated protein kinases (MAPKs), which then stimulated NF-κB to release proinflammatory mediators in the TMT-treated BV-2 cells. PMID:26221064

  1. Effect of epidermal growth factor (EGF) on the phosphorylation of mitogen-activated protein kinase (MAPK) in the bovine oviduct in vitro: Alteration by heat stress

    PubMed Central

    WIJAYAGUNAWARDANE, Missaka P. B.; HAMBRUCH, Nina; HAEGER, Jan-Dirk; PFARRER, Christiane

    2015-01-01

    Epidermal growth factor (EGF) has been shown to be involved in control of the oviductal microenvironment. To elucidate the potential mechanisms responsible for the detrimental effect of heat stress and to identify the relation with the endocrine status, the effects of EGF on the level of phosphorylated mitogen-activated-protein kinase (MAPK) and proliferation of bovine oviductal epithelial cells (OECs) exposed to different cyclic ovarian steroidal environments (luteal phase (LP), follicular phase (FP) and postovulatory phase (PO)) and temperatures (mild heat stress (40 C) and severe heat stress (43 C)) were investigated. Western blot was performed to evaluate phosphorylated MAPK, while proliferation was analyzed by MTT assay. Stimulation of OECs with EGF alone or with EGF in the PO and FP environments significantly increased the amount of phosphorylated MAPK, with MAPK 44 phosphorylation being highest during exposure to PO conditions. These effects were not observed in the LP. Heat treatment completely blocked effects of EGF on phosphorylated MAPK. Additionally, severe heat stress led to a significantly lower basal level of phosphorylated MAPK. PD98059 (MAPK inhibitor) completely abolished EGF-stimulated MAPK phosphorylation and OECs proliferation. Overall the results indicate that EGF has the potential to increase the amount of phosphorylated MAPK in OECs and therefore could be involved in regulation of the bovine oviductal microenvironment. However, these regulatory mechanisms may be compromised in the presence of heat stress (high ambient temperature), leading to low fertility rates and impaired embryo survival. PMID:26050642

  2. Importin-7 mediates memory consolidation through regulation of nuclear translocation of training-activated MAPK in Drosophila.

    PubMed

    Li, Qian; Zhang, Xuchen; Hu, Wantong; Liang, Xitong; Zhang, Fang; Wang, Lianzhang; Liu, Zhong-Jian; Zhong, Yi

    2016-03-15

    Translocation of signaling molecules, MAPK in particular, from the cytosol to nucleus represents a universal key element in initiating the gene program that determines memory consolidation. Translocation mechanisms and their behavioral impact, however, remain to be determined. Here, we report that a highly conserved nuclear transporter, Drosophila importin-7 (DIM-7), regulates import of training-activated MAPK for consolidation of long-term memory (LTM). We show that silencing DIM-7 functions results in impaired LTM, whereas overexpression of DIM-7 enhances LTM. This DIM-7-dependent regulation of LTM is confined to a consolidation time window and in mushroom body neurons. Image data show that bidirectional alteration in DIM-7 expression results in proportional changes in the intensity of training-activated MAPK accumulated within the nuclei of mushroom body neurons during LTM consolidation. Such DIM-7-regulated nuclear accumulation of activated MAPK is observed only in the training specified for LTM induction and determines the amplitude, but not the time course, of memory consolidation. PMID:26929354

  3. Naringin inhibits ROS-activated MAPK pathway in high glucose-induced injuries in H9c2 cardiac cells.

    PubMed

    Chen, Jingfu; Guo, Runmin; Yan, Hai; Tian, Lihong; You, Qiong; Li, Shanghai; Huang, Ruina; Wu, Keng

    2014-04-01

    Naringin, an active flavonoid isolated from citrus fruit extracts, exhibits biological and pharmacological properties, such as antioxidant activity and antidiabetic effect. Mitogen-activated protein kinase (MAPK) signalling pathway has been shown to participate in hyperglycaemia-induced injury. The present study tested the hypothesis that naringin protects against high glucose (HG)-induced injuries by inhibiting MAPK pathway in H9c2 cardiac cells. To examine this, the cells were treated with 35 mM glucose (HG) for 24 hr to establish a HG-induced cardiomyocyte injury model. The cells were pre-treated with 80 μM naringin for 2 hr before exposure to HG. The findings of this study showed that exposure of H9c2 cells to HG for 24 hr markedly induced injuries, as evidenced by a decrease in cell viability, increases in apoptotic cells and reactive oxygen species (ROS) production, as well as dissipation of mitochondrial membrance potential (MMP). These injuries were significantly attenuated by the pre-treatment of cells with either naringin or SB203580 (a selective inhibitor of p38 MAPK) or U0126 (a selective inhibitor of extracellular signal regulated kinase 1/2, ERK1/2) or SP600125 (a selective inhibitor of c-jun N-termanal kinase, JNK) before exposure to HG, respectively. Furthermore, exposure of cells to HG increased the phosphorylation of p38 MAPK, ERK1/2 and JNK. The increased activation of MAPK pathway was ameliorated by pre-treatment with either naringin or N-acetyl-L-cysteine (NAC), a ROS scavenger, which also reduced HG-induced cytotoxicity and apoptosis, leading to increase in cell viability and decrease in apoptotic cells. In conclusion, our findings provide new evidence for the first time that naringin protects against HG-induced injuries by inhibiting the activation of MAPK (p38 MAPK, ERK1/2 and JNK) and oxidative stress in H9c2 cells. PMID:24118820

  4. 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. PMID:23719850

  5. GSH1, which encodes gamma-glutamylcysteine synthetase, is a target gene for yAP-1 transcriptional regulation.

    PubMed Central

    Wu, A L; Moye-Rowley, W S

    1994-01-01

    Changes in gene dosage of the YAP1 gene, encoding the yAP-1 transcriptional regulatory protein, cause profound alterations in cellular drug and metal resistance. Previous studies on yAP-1 action in yeast cells have used the AP-1 response element (ARE) from simian virus 40 as an artificial site for yAP-1-mediated transcriptional activation. No authentic yeast target sites for control of gene expression by yAP-1 are known. Here we show that the GSH1 gene, encoding gamma-glutamylcysteine synthetase, is transcriptionally responsive to the yAP-1 protein. GSH1 encodes the rate-limiting step in yeast glutathione biosynthesis and contains within its promoter region a DNA element that matches the ARE in 11 of 12 positions. The GSH1 yAP-1 response element (YRE) was recognized by yAP-1 protein in vitro. Northern (RNA) blot analysis showed that GSH1 mRNA levels were responsive to YAP1 gene dosage. A site-directed mutation in the YRE that blocked yAP-1 binding in vitro prevented the mutant GSH1 promoter from responding to elevation in YAP1 gene dosage. A delta gsh1 mutant strain was constructed and unable to grow in the absence of exogenous glutathione. A mutant GSH1 gene lacking the YRE was unable to confer normal cadmium tolerance, although other yAP-1-mediated phenotypes remained normal. Thus, GSH1 is one of several genes that are transcriptionally controlled by yAP-1 and influence drug resistance. Images PMID:7915005

  6. Wnt-11 signaling leads to down-regulation of the Wnt/{beta}-catenin, JNK/AP-1 and NF-{kappa}B pathways and promotes viability in the CHO-K1 cells

    SciTech Connect

    Railo, Antti; Nagy, Irina I.; Kilpelaeinen, Pekka Vainio, Seppo

    2008-08-01

    The Wnt family of glycoprotein growth factors controls a number of central cellular processes such as proliferation, differentiation and ageing. All the Wnt proteins analyzed so far either activate or inhibit the canonical {beta}-catenin signaling pathway that regulates transcription of the target genes. In addition, some of them activate noncanonical signaling pathways that involve components such as the JNK, heterotrimeric G proteins, protein kinase C, and calmodulin-dependent protein kinase II, although the precise signaling mechanisms are only just beginning to be revealed. We demonstrate here that Wnt-11 signaling is sufficient to inhibit not only the canonical {beta}-catenin mediated Wnt signaling but also JNK/AP-1 and NF-{kappa}B signaling in the CHO cells, thus serving as a noncanonical Wnt ligand in this system. Inhibition of the JNK/AP-1 pathway is mediated in part by the MAPK kinase MKK4 and Akt. Moreover, protein kinase C is involved in the regulation of JNK/AP-1 by Wnt-11, but not of the NF-{kappa}B pathway. Consistent with the central role of Akt, JNK and NF-{kappa}B in cell survival and stress responses, Wnt-11 signaling promotes cell viability. Hence Wnt-11 is involved in coordination of key signaling pathways.

  7. Oridonin upregulates PTEN through activating p38 MAPK and inhibits proliferation in human colon cancer cells.

    PubMed

    Wu, Qiu-Xiang; Yuan, Shuang-Xue; Ren, Chun-Mei; Yu, Yu; Sun, Wen-Juan; He, Bai-Cheng; Wu, Ke

    2016-06-01

    Oridonin (ORI) has been reported as an antiproliferation and apoptosis-inducing natural product in various cancer cells. However, the exact molecular mechanism underlying these effects remains unclear. In the present study, we demonstrated the antiproliferation effect of ORI in HCT116 cells, and analyzed the possible molecular mechanism which mediates this effect. We found that ORI inhibits proliferation, induces cell cycle arrest and apoptosis in HCT116 cells, thus also tumor growth. Mechanically, we found that ORI has no substantial effect on mRNA expression of phosphatase and tensin homologue (PTEN), but increases the total protein level of PTEN and markedly reduces the phosphorylation of PTEN; Exogenous expression of PTEN potentiates the anticancer effect of ORI, while knockdown of PTEN attenuates it. ORI also increases the phosphorylation of p38 MAPK, and p38 MAPK-specific inhibitor reduces the antiproliferation effect ORI in HCT116 cells. Moreover, inhibition of p38 MAPK increases the phosphorylation of PTEN, and reverses ORI-induced decrease of PTEN phosphorylation. Our findings suggested that ORI may be a potential anticancer drug for colon cancer, this effect may be mediated by enhancing the function of PTEN through reducing its phosphorylation, which may be resulted from the ORI-induced activation of p38 MAPK. PMID:27108927

  8. Immunosuppressant MPA Modulates Tight Junction through Epigenetic Activation of MLCK/MLC-2 Pathway via p38MAPK

    PubMed Central

    Khan, Niamat; Pantakani, D. V. Krishna; Binder, Lutz; Qasim, Muhammad; Asif, Abdul R.

    2015-01-01

    Background: Mycophenolic acid (MPA) is an important immunosuppressive drug (ISD) prescribed to prevent graft rejection in the organ transplanted patients, however, its use is also associated with adverse side effects like sporadic gastrointestinal (GI) disturbances. Recently, we reported the MPA induced tight junctions (TJs) deregulation which involves MLCK/MLC-2 pathway. Here, we investigated the global histone acetylation as well as gene-specific chromatin signature of several genes associated with TJs regulation in Caco-2 cells after MPA treatment. Results: The epigenetic analysis shows that MPA treatment increases the global histone acetylation levels as well as the enrichment for transcriptional active histone modification mark (H3K4me3) at promoter regions of p38MAPK, ATF-2, MLCK, and MLC-2. In contrast, the promoter region of occludin was enriched for transcriptional repressive histone modification mark (H3K27me3) after MPA treatment. In line with the chromatin status, MPA treatment increased the expression of p38MAPK, ATF-2, MLCK, and MLC-2 both at transcriptional and translational level, while occludin expression was negatively influenced. Interestingly, the MPA induced gene expression changes and functional properties of Caco-2 cells could be blocked by the inhibition of p38MAPK using a chemical inhibitor (SB203580). Conclusions: Collectively, our results highlight that MPA disrupts the structure of TJs via p38MAPK-dependent activation of MLCK/MLC-2 pathway that results in decreased integrity of Caco-2 monolayer. These results led us to suggest that p38MAPK-mediated lose integrity of epithelial monolayer could be the possible cause of GI disturbance (barrier dysfunction) in the intestine, leading to leaky style diarrhea observed in the organ-transplanted patients treated with MPA. PMID:26733876

  9. GNA14 Somatic Mutation Causes Congenital and Sporadic Vascular Tumors by MAPK Activation.

    PubMed

    Lim, Young H; Bacchiocchi, Antonella; Qiu, Jingyao; Straub, Robert; Bruckner, Anna; Bercovitch, Lionel; Narayan, Deepak; McNiff, Jennifer; Ko, Christine; Robinson-Bostom, Leslie; Antaya, Richard; Halaban, Ruth; Choate, Keith A

    2016-08-01

    Vascular tumors are among the most common neoplasms in infants and children; 5%-10% of newborns present with or develop lesions within the first 3 months of life. Most are benign infantile hemangiomas that typically regress by 5 years of age; other vascular tumors include congenital tufted angiomas (TAs), kaposiform hemangioendotheliomas (KHEs), and childhood lobular capillary hemangiomas (LCHs). Some of these lesions can become locally invasive and unresponsive to pharmacologic intervention, leading to significant complications. Recent investigation has revealed that activating mutations in HRAS, KRAS, NRAS, GNAQ, and GNA11 can cause certain types of rare childhood vascular tumors, and we have now identified causal recurrent somatic activating mutations in GNA14 by whole-exome and targeted sequencing. We found somatic activating GNA14 c.614A>T (p.Gln205Leu) mutations in one KHE, one TA, and one LCH and a GNA11 c.547C>T (p.Arg183Cys) mutation in two LCH lesions. We examined mutation pathobiology via expression of mutant GNA14 or GNA11 in primary human endothelial cells and melanocytes. GNA14 and GNA11 mutations induced changes in cellular morphology and rendered cells growth-factor independent by upregulating the MAPK pathway. Our findings identify GNA14 mutations as a cause of childhood vascular tumors, offer insight into mechanisms of oncogenic transformation by mutations affecting Gaq family members, and identify potential targets for therapeutic intervention. PMID:27476652

  10. A Trichoderma atroviride stress-activated MAPK pathway integrates stress and light signals.

    PubMed

    Esquivel-Naranjo, Edgardo Ulises; García-Esquivel, Mónica; Medina-Castellanos, Elizabeth; Correa-Pérez, Víctor Alejandro; Parra-Arriaga, Jorge Luis; Landeros-Jaime, Fidel; Cervantes-Chávez, José Antonio; Herrera-Estrella, Alfredo

    2016-06-01

    Cells possess stress-activated protein kinase (SAPK) signalling pathways, which are activated practically in response to any cellular insult, regulating responses for survival and adaptation to harmful environmental changes. To understand the function of SAPK pathways in T. atroviride, mutants lacking the MAPKK Pbs2 and the MAPK Tmk3 were analysed under several cellular stresses, and in their response to light. All mutants were highly sensitive to cellular insults such as osmotic and oxidative stress, cell wall damage, high temperature, cadmium, and UV irradiation. Under oxidative stress, the Tmk3 pathway showed specific roles during development, which in conidia are essential for tolerance to oxidant agents and appear to play a minor role in mycelia. The function of this pathway was more evident in Δpbs2 and Δtmk3 mutant strains when combining oxidative stress or cell wall damage with light. Light stimulates tolerance to osmotic stress through Tmk3 independently of the photoreceptor Blr1. Strikingly, photoconidiation and expression of blue light regulated genes was severally affected in Δtmk3 and Δpbs2 strains, indicating that this pathway regulates light responses. Furthermore, Tmk3 was rapidly phosphorylated upon light exposure. Thus, our data indicate that Tmk3 signalling cooperates with the Blr photoreceptor complex in the activation of gene expression. PMID:26878111