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. Copyright © 2016 Elsevier Inc. All rights reserved.

Role of Bioavailable Iron in Coal Dust-Induced Activation of Activator Protein-1 and Nuclear Factor of Activated T Cells

PubMed Central

Huang, Chuanshu; Li, Jingxia; Zhang, Qi; Huang, Xi

2010-01-01

Activator protein-1 (AP-1) and nuclear factor of activated T cells (NFAT) are two important transcription factors responsible for the regulation of cytokines, which are involved in cell proliferation and inflammation. Coal workers’ pneumoconiosis (CWP) is an occupational lung disease that may be related to chronic inflammation caused by coal dust exposure. In the present study, we demonstrate that coal from the Pennsylvania (PA) coalmine region, which has a high prevalence of CWP, can activate both AP-1 and NFAT in JB6 mouse epidermal cells. In contrast, coal from the Utah (UT) coalmine region, which has a low prevalence of CWP, has no such effects. The PA coal stimulates mitogen-activated protein kinase (MAPK) family members of extracellular signal-regulated kinases (ERKs) and p38 MAPK but not c-Jun-NH2-terminal kinases, as determined by the phosphorylation assay. The increase in AP-1 by the PA coal was completely eliminated by the pretreatment of cells with PD98059, a specific MAPK kinase inhibitor, and SB202190, a p38 kinase inhibitor, further confirming that the PA coal-induced AP-1 activation is mediated through ERKs and p38 MAPK pathways. Deferoxamine (DFO), an iron chelator, synergistically enhanced the PA coal-induced AP-1 activity, but inhibited NFAT activity. For comparison, cells were treated with ferrous sulfate and/or DFO. We have found that iron transactivated both AP-1 and NFAT, and DFO further enhanced iron-induced AP-1 activation but inhibited NFAT. These results indicate that activation of AP-1 and NFAT by the PA coal is through bioavailable iron present in the coal. These data are in agreement with our previous findings that the prevalence of CWP correlates well with levels of bioavailable iron in coals from various mining regions. PMID:12397016

Chk1 inhibition activates p53 through p38 MAPK in tetraploid cancer cells.

PubMed

Vitale, Ilio; Senovilla, Laura; Galluzzi, Lorenzo; Criollo, Alfredo; Vivet, Sonia; Castedo, Maria; Kroemer, Guido

2008-07-01

We have previously shown that tetraploid cancer cells succumb through a p53-dependent apoptotic pathway when checkpoint kinase 1 (Chk1) is depleted by small interfering RNAs (siRNAs) or inhibited with 7-hydroxystaurosporine (UCN-01). Here, we demonstrate that Chk1 inhibition results in the activating phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK). Depletion of p38 MAPK by transfection with a siRNA targeting the alpha isoform of p38 MAPK (p38alpha MAPK) abolishes the phosphorylation of p53 on serines 15 and 46 that is induced by Chk1 knockdown. The siRNA-mediated downregulation and pharmacological inhibition of p38alpha MAPK (with SB 203580) also reduces cell death induced by Chk1 knockdown or UCN-01. These results underscore the role of p38 MAPK as a pro-apoptotic kinase in the p53-dependant pathway for the therapeutic elimination of polyploidy cells.

Helicobacter pylori neutrophil-activating protein induces release of histamine and interleukin-6 through G protein-mediated MAPKs and PI3K/Akt pathways in HMC-1 cells.

PubMed

Tsai, Chung-Che; Kuo, Ting-Yu; Hong, Zhi-Wei; Yeh, Ying-Chieh; Shih, Kuo-Shun; Du, Shin-Yi; Fu, Hua-Wen

2015-01-01

Helicobacter pylori neutrophil-activating protein (HP-NAP) activates several innate leukocytes including neutrophils, monocytes, and mast cells. It has been reported that HP-NAP induces degranulation and interleukin-6 (IL-6) secretion of rat peritoneal mast cells. However, the molecular mechanism is not very clear. Here, we show that HP-NAP activates human mast cell line-1 (HMC-1) cells to secrete histamine and IL-6. The secretion depends on pertussis toxin (PTX)-sensitive heterotrimeric G proteins but not on Toll-like receptor 2. Moreover, HP-NAP induces PTX-sensitive G protein-mediated activation of extracellular signal-regulated kinase 1/2 (ERK1/2), p38-mitogen-activated protein kinase (p38 MAPK), and Akt in HMC-1 cells. Inhibition of ERK1/2, p38 MAPK, or phosphatidylinositol 3-kinase (PI3K) suppresses HP-NAP-induced release of histamine and IL-6 from HMC-1 cells. Thus, the activation of HMC-1 cells by HP-NAP is through Gi-linked G protein-coupled receptor-mediated MAPKs and PI3K/Akt pathways.

Coal-induced interleukin-6 gene expression is mediated through ERKs and p38 MAPK pathways.

PubMed

Huang, X; Zhang, Q

2003-08-15

In the present study, we have tested the ability of coal dust to stimulate kinase phosphorylation of activator protein-1 (AP-1) signal transduction pathways and production of interleukin-6 (IL-6) in both mouse epidermal JB6 and human lung epithelial A549 cells. Seven coal samples from three coalmine regions of Pennsylvania (PA), West Virginia (WV), and Utah (UT) with high, medium, and low prevalence of coal workers' pneumoconiosis (CWP), respectively, were investigated. Results from the present study indicate that three PA coals stimulated the mitogen-activated protein kinase (MAPK) family of extracellular signal-regulated kinases (ERKs) and p38 MAPK, but not c-Jun-NH2-terminal kinases (JNKs) in human lung A549 cells. The effects of three UT coals on the kinase phosphorylation were less as compared to those of the PA coals. Coal dusts from three coalmine regions induced IL-6 in a dose-dependent manner in both JB6 and A549 cells. Interestingly, levels of IL-6 in both cells treated with coals from three coalmine regions correlated well with CWP prevalence from that region. To assess the role of AP-1 pathways in coal-mediated transcriptional activation of IL-6, various inhibitors were used in cells treated with one PA coal, which induced a maximal response. It was found that the increase in IL-6 protein and mRNA by the PA coal was completely eliminated by the pretreatment of both cell types with PD98059, a specific MEK1 inhibitor, and SB202190, a p38 kinase inhibitor. Our results indicate that coal dust can stimulate IL-6 release from mouse epidermal JB6 cells and human lung epithelial A549 cells, and the coal-induced IL-6 increase may involve ERKs and p38 MAPK pathways.

BDNF-TrkB signaling through Erk1/2MAPK phosphorylation mediates the enhancement of fear memory induced by glucocorticoids

PubMed Central

Revest, J-M; Le Roux, A; Roullot-Lacarrière, V; Kaouane, N; Vallée, M; Kasanetz, F; Rougé-Pont, F; Tronche, F; Desmedt, A; Piazza, P V

2014-01-01

Activation of glucocorticoid receptors (GR) by glucocorticoid hormones (GC) enhances contextual fear memories through the activation of the Erk1/2MAPK signaling pathway. However, the molecular mechanism mediating this effect of GC remains unknown. Here we used complementary molecular and behavioral approaches in mice and rats and in genetically modified mice in which the GR was conditionally deleted (GRNesCre). We identified the tPA-BDNF-TrkB signaling pathway as the upstream molecular effectors of GR-mediated phosphorylation of Erk1/2MAPK responsible for the enhancement of contextual fear memory. These findings complete our knowledge of the molecular cascade through which GC enhance contextual fear memory and highlight the role of tPA-BDNF-TrkB-Erk1/2MAPK signaling pathways as one of the core effectors of stress-related effects of GC. PMID:24126929

Rosiglitazone attenuates NF-{kappa}B-dependent ICAM-1 and TNF-{alpha} production caused by homocysteine via inhibiting ERK{sub 1/2}/p38MAPK activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bai, Yong-Ping; Liu, Yu-Hui; Chen, Jia

2007-08-17

Previous studies demonstrated an important interaction between nuclear factor-kappaB (NF-{kappa}B) activation and homocysteine (Hcy)-induced cytokines expression in endothelial cells and vascular smooth muscle cells. However, the underlying mechanism remains illusive. In this study, we investigated the effects of Hcy on NF-{kappa}B-mediated sICAM-1, TNF-{alpha} production and the possible involvement of ERK{sub 1/2}/p38MAPK pathway. The effects of rosiglitazone intervention were also examined. Our results show that Hcy increased the levels of sICAM-1 and TNF-{alpha} in cultured human umbilical vein endothelial cells (HUVECs) in a time- and concentration-dependent manner. This effect was significantly depressed by rosiglitazone and different inhibitors (PDTC, NF-{kappa}B inhibitor; PD98059,more » MEK inhibitor; SB203580, p38MAPK specific inhibitor; and staurosporine, PKC inhibitor). Next, we investigated the effect of Hcy on ERK{sub 1/2}/p38MAPK pathway and NF-{kappa}B activity in HUVECs. The results show that Hcy activated both ERK{sub 1/2}/p38MAPK pathway and NF-{kappa}B-DNA-binding activity. These effects were markedly inhibited by rosiglitazone as well as other inhibitors (SB203580, PD98059, and PDTC). Further, the pretreatment of staurosporine abrogated ERK{sub 1/2}/p38MAPK phosphorylation, suggesting that Hcy-induced ERK{sub 1/2}/p38MAPK activation is associated with PKC activity. Our results provide evidence that Hcy-induced NF-{kappa}B activation was mediated by activation of ERK{sub 1/2}/p38MAPK pathway involving PKC activity. Rosiglitazone reduces the NF-{kappa}B-mediated sICAM-1 and TNF-{alpha} production induced by Hcy via inhibition of ERK{sub 1/2}/p38MAPK pa0011thw.« less

Role of bioavailable iron in coal dust-induced activation of activator protein-1 and nuclear factor of activated T cells: difference between Pennsylvania and Utah coal dusts.

PubMed

Huang, Chuanshu; Li, Jingxia; Zhang, Qi; Huang, Xi

2002-11-01

Activator protein-1 (AP-1) and nuclear factor of activated T cells (NFAT) are two important transcription factors responsible for the regulation of cytokines, which are involved in cell proliferation and inflammation. Coal workers' pneumoconiosis (CWP) is an occupational lung disease that may be related to chronic inflammation caused by coal dust exposure. In the present study, we demonstrate that coal from the Pennsylvania (PA) coalmine region, which has a high prevalence of CWP, can activate both AP-1 and NFAT in JB6 mouse epidermal cells. In contrast, coal from the Utah (UT) coalmine region, which has a low prevalence of CWP, has no such effects. The PA coal stimulates mitogen-activated protein kinase (MAPK) family members of extracellular signal-regulated kinases (ERKs) and p38 MAPK but not c-Jun-NH(2)-terminal kinases, as determined by the phosphorylation assay. The increase in AP-1 by the PA coal was completely eliminated by the pretreatment of cells with PD98059, a specific MAPK kinase inhibitor, and SB202190, a p38 kinase inhibitor, further confirming that the PA coal-induced AP-1 activation is mediated through ERKs and p38 MAPK pathways. Deferoxamine (DFO), an iron chelator, synergistically enhanced the PA coal-induced AP-1 activity, but inhibited NFAT activity. For comparison, cells were treated with ferrous sulfate and/or DFO. We have found that iron transactivated both AP-1 and NFAT, and DFO further enhanced iron-induced AP-1 activation but inhibited NFAT. These results indicate that activation of AP-1 and NFAT by the PA coal is through bioavailable iron present in the coal. These data are in agreement with our previous findings that the prevalence of CWP correlates well with levels of bioavailable iron in coals from various mining regions.

The AP-1 transcription factor FOSL1 causes melanocyte reprogramming and transformation.

PubMed

Maurus, K; Hufnagel, A; Geiger, F; Graf, S; Berking, C; Heinemann, A; Paschen, A; Kneitz, S; Stigloher, C; Geissinger, E; Otto, C; Bosserhoff, A; Schartl, M; Meierjohann, S

2017-09-07

The MAPK pathway is activated in the majority of melanomas and is the target of therapeutic approaches. Under normal conditions, it initiates the so-called immediate early response, which encompasses the transient transcription of several genes belonging to the AP-1 transcription factor family. Under pathological conditions, such as continuous MAPK pathway overactivation due to oncogenic alterations occurring in melanoma, these genes are constitutively expressed. The consequences of a permanent expression of these genes are largely unknown. Here, we show that FOSL1 is the main immediate early AP-1 member induced by melanoma oncogenes. We first examined its role in established melanoma cells. We found that FOSL1 is involved in melanoma cell migration as well as cell proliferation and anoikis-independent growth, which is mediated by the gene product of its target gene HMGA1, encoding a multipotent chromatin modifier. As FOSL1 expression is increased in patient melanoma samples compared to nevi, we investigated the effect of enhanced FOSL1 expression on melanocytes. Intriguingly, we found that FOSL1 acts oncogenic and transforms melanocytes, enabling subcutaneous tumor growth in vivo. During the process of transformation, FOSL1 reprogrammed the melanocytes and downregulated MITF in a HMGA1-dependent manner. At the same time, AXL was upregulated, leading to a shift in the MITF/AXL balance. Furthermore, FOSL1 re-enforced pro-tumorigenic transcription factors MYC, E2F3 and AP-1. Together, this led to the enhancement of several growth-promoting processes, such as ribosome biogenesis, cellular detachment and pyrimidine metabolism. Overall, we demonstrate that FOSL1 is a novel reprogramming factor for melanocytes with potent tumor transformation potential.

Sulforaphane suppresses vascular adhesion molecule-1 expression in TNF-α-stimulated mouse vascular smooth muscle cells: involvement of the MAPK, NF-κB and AP-1 signaling pathways.

PubMed

Kim, Ji-Yun; Park, Hye-Jin; Um, Sung Hee; Sohn, Eun-Hwa; Kim, Byung-Oh; Moon, Eun-Yi; Rhee, Dong-Kwon; Pyo, Suhkneung

2012-01-01

Atherosclerosis is a long-term inflammatory disease of the arterial wall. Increased expression of the cell adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) is associated with increased proliferation of vascular smooth muscle cells (VSMCs), leading to increased neointima or atherosclerotic lesion formation. Therefore, the functional inhibition of adhesion molecules could be a critical therapeutic target of inflammatory disease. In the present study, we investigate the effect of sulforaphane on the expression of VCAM-1 induced by TNF-α in cultured mouse vascular smooth muscle cell lines. Pretreatment of VSMCs for 2h with sulforaphane (1-5μg/ml) dose-dependently inhibited TNF-α-induced adhesion of THP-1 monocytic cells and protein expression of VCAM-1. Sulforaphane also suppressed TNF-α-induced production of intracellular reactive oxygen species (ROS) and activation of p38, ERK and JNK. Furthermore, sulforaphane inhibited NK-κB and AP-1 activation induced by TNF-α. Sulforaphane inhibited TNF-α-induced ΙκΒ kinase activation, subsequent degradation of ΙκΒα and nuclear translocation of p65 NF-κB and decreased c-Jun and c-Fos protein level. This study suggests that sulforaphane inhibits the adhesive capacity of VSMC and downregulates the TNF-α-mediated induction of VCAM-1 in VSMC by inhibiting the MAPK, NF-κB and AP-1 signaling pathways and intracellular ROS production. Thus, sulforaphane may have beneficial effects to suppress inflammation within the atherosclerotic lesion. Copyright © 2011 Elsevier Inc. All rights reserved.

NOS1 mediates AP1 nuclear translocation and inflammatory response.

PubMed

Srivastava, Mansi; Baig, Mirza S

2018-06-01

A hallmark of the AP1 functioning is its nuclear translocation, which induces proinflammatory cytokine expression and hence the inflammatory response. After endotoxin shock AP1 transcription factor, which comprises Jun, ATF2, and Fos family of proteins, translocates into the nucleus and induces proinflammatory cytokine expression. In the current study, we found, NOS1 inhibition prevents nuclear translocation of the AP1 transcription factor subunits. Pharmacological inhibition of NOS1 impedes translocation of subunits into the nucleus, suppressing the transcription of inflammatory genes causing a diminished inflammatory response. In conclusion, the study shows the novel mechanism of NOS1- mediated AP1 nuclear translocation, which needs to be further explored. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

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

Quinacrine induces apoptosis in human leukemia K562 cells via p38 MAPK-elicited BCL2 down-regulation and suppression of ERK/c-Jun-mediated BCL2L1 expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Changchien, Jung-Jung; Chen, Ying-Jung; Huang, Chia-Hui

2015-04-01

Although previous studies have revealed the anti-cancer activity of quinacrine, its effect on leukemia is not clearly resolved. We sought to explore the cytotoxic effect and mechanism of quinacrine action in human leukemia K562 cells. Quinacrine induced K562 cell apoptosis accompanied with ROS generation, mitochondrial depolarization, and down-regulation of BCL2L1 and BCL2. Upon exposure to quinacrine, ROS-mediated p38 MAPK activation and ERK inactivation were observed in K562 cells. Quinacrine-induced cell death and mitochondrial depolarization were suppressed by the p38MAPK inhibitor SB202190 and constitutively active MEK1 over-expression. Activation of p38 MAPK was shown to promote BCL2 degradation. Further, ERK inactivation suppressedmore » c-Jun-mediated transcriptional expression of BCL2L1. Over-expression of BCL2L1 and BCL2 attenuated quinacrine-evoked mitochondrial depolarization and rescued the viability of quinacrine-treated cells. Taken together, our data indicate that quinacrine-induced K562 cell apoptosis is mediated through mitochondrial alterations triggered by p38 MAPK-mediated BCL2 down-regulation and suppression of ERK/c-Jun-mediated BCL2L1 expression. - Highlights: • Quinacrine induces K562 cell apoptosis via down-regulation of BCL2 and BCL2L1. • Quinacrine induces p38 MAPK activation and ERK inactivation in K562 cells. • Quinacrine elicits p38 MAPK-mediated BCL2 down-regulation. • Quinacrine suppresses ERK/c-Jun-mediated BCL2L1 expression.« less

Activated Rho Kinase Mediates Diabetes-Induced Elevation of Vascular Arginase Activation and Contributes to Impaired Corpora Cavernosa Relaxation: Possible Involvement of p38 MAPK Activation

PubMed Central

Nunes, Kenia P.; Yao, Lin; Liao, James K.; Webb, R. Clinton; Caldwell, Ruth B.; Caldwell, R. William

2013-01-01

Introduction Activated RhoA/Rho kinase (ROCK) has been implicated in diabetes-induced erectile dysfunction. Earlier studies have demonstrated involvement of ROCK pathway in the activation of arginase in endothelial cells. However, signaling pathways activated by ROCK in the penis remain unclear. Aim We tested whether ROCK and p38 MAPK are involved in the elevation of arginase activity and subsequent impairment of corpora cavernosal (CC) relaxation in diabetes. Methods Eight weeks after streptozotocin-induced diabetes, vascular functional studies, arginase activity assay, and protein expression of RhoA, ROCK, phospho-p38 MAPK, p38 MAPK, phospho-MYPT-1Thr850, MYPT-1 and arginase levels were assessed in CC tissues from nondiabetic wild type (WT), diabetic (D) WT (WT + D), partial ROCK 2+/− knockout (KO), and ROCK 2+/− KO + D mice. Main Outcome Measures The expression of RhoA, ROCK 1 and 2, phosphorylation of MYPT-1Thr850 and p38 MAPK, arginase activity/expression, endothelial- and nitrergic-dependent relaxation of CC was assayed. Results Diabetes significantly reduced maximum relaxation (Emax) to both endothelium-dependent acetylcholine (WT + D: Emax; 61 ± 4% vs. WT: Emax; 75 ± 2%) and nitrergic nerve stimulation. These effects were associated with increased expression of active RhoA, ROCK 2, phospho-MYPT-1Thr850, phospho-p38 MAPK, arginase II, and activity of corporal arginase (1.6-fold) in WT diabetic CC. However, this impairment in CC of WT + D mice was absent in heterozygous ROCK 2+/− KO + D mice for acetylcholine (Emax: 80 ± 5%) and attenuated for nitrergic nerve-induced relaxation. CC of ROCK 2+/− KO + D mice showed much less ROCK activity, did not exhibit p38 MAPK activation, and had reduced arginase activity and arginase II expression. These findings indicate that ROCK 2 mediates diabetes-induced elevation of arginase activity. Additionally, pretreatment of WT diabetic CC with inhibitors of arginase (ABH) or p38 MAPK (SB203580) partially prevented

w09, a novel autophagy enhancer, induces autophagy-dependent cell apoptosis via activation of the EGFR-mediated RAS-RAF1-MAP2K-MAPK1/3 pathway.

PubMed

Zhang, Pinghu; Zheng, Zuguo; Ling, Li; Yang, Xiaohui; Zhang, Ni; Wang, Xue; Hu, Maozhi; Xia, Yu; Ma, Yiwen; Yang, Haoran; Wang, Yunyi; Liu, Hongqi

2017-07-03

The EGFR (epidermal growth factor receptor) signaling pathway is frequently deregulated in many malignancies. Therefore, targeting the EGFR pathway is regarded as a promising strategy for anticancer drug discovery. Herein, we identified a 2-amino-nicotinonitrile compound (w09) as a novel autophagy enhancer, which potently induced macroautophagy/autophagy and consequent apoptosis in gastric cancer cells. Mechanistic studies revealed that EGFR-mediated activation of the RAS-RAF1-MAP2K-MAPK1/3 signaling pathway played a critical role in w09-induced autophagy and apoptosis of gastric cancer cells. Inhibition of the MAPK1/3 pathway with U0126 or blockade of autophagy by specific chemical inhibitors markedly attenuated the effect of w09-mediated growth inhibition and caspase-dependent apoptosis. Furthermore, these conclusions were supported by knockdown of ATG5 or knockout of ATG5 and/or ATG7. Notably, w09 increased the expression of SQSTM1 by transcription, and knockout of SQSTM1 or deleting the LC3-interaction region domain of SQSTM1, significantly inhibited w09-induced PARP1 cleavage, suggesting the central role played by SQSTM1 in w09-induced apoptosis. In addition, in vivo administration of w09 effectively inhibited tumor growth of SGC-7901 xenografts. Hence, our findings not only suggested that activation of the EGFR-RAS-RAF1-MAP2K-MAPK1/3 signaling pathway may play a critical role in w09-induced autophagy and apoptosis, but also imply that induction of autophagic cancer cell death through activation of the EGFR pathway may be a potential therapeutic strategy for EGFR-disregulated gastric tumors.

Degraded λ-carrageenan activates NF-κB and AP-1 pathways in macrophages and enhances LPS-induced TNF-α secretion through AP-1.

PubMed

Chen, Haimin; Wang, Feng; Mao, Haihua; Yan, Xiaojun

2014-07-01

Carrageenan (CGN), a high molecular weight sulfated polysaccharide, is a traditional ingredient used in food industry. Its degraded forms have been identified as potential carcinogens, although the mechanism remains unclear. The effects of degraded λ-carrageenan (λ-dCGN) on murine RAW264.7 cells and human THP-1-derived macrophage cells were investigated by studying its actions on tumor necrosis factor alpha (TNF-α) secretion, Toll-like receptor 4 (TLR4) expression, and activation of nuclear factor-κb (NF-κB) and activation protein-1 (AP-1) pathways. We found that λ-dCGN was much stronger than native λ-CGN in the activation of macrophages to secrete TNF-α. Treatment of RAW264.7 cells with λ-dCGN resulted in the upregulation of TLR4, CD14 and MD-2 expressions, but it did not increase the binding of lipopolysacchride (LPS) with macrophages. Meanwhile, λ-dCGN treatment activated NF-κB via B-cell lymphoma/leukemia 10 (Bcl10) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) phosphorylation. In addition, λ-dCGN induced extracellular signal-regulated kinases/1/2/mitogen-activated protein kinases (ERK1/2/MAPK) and AP-1 activation. Interestingly, pretreatment of RAW264.7 cells with λ-dCGN markedly enhanced LPS-stimulated TNF-α secretion. This pretreatment resulted in the enhanced phosphorylation of ERK1/2 and c-Jun N-terminal kinase (JNK) and intensified activation of AP-1. λ-dCGN induced an inflammatory reaction via both NF-κB and AP-1, and enhanced the inflammatory effect of LPS through AP-1 activation. The study demonstrated the role of λ-dCGN to induce the inflammatory reaction and to aggravate the effect of LPS on macrophages, suggesting that λ-dCGN produced during food processing and gastric digestion may be a safety concern. Copyright © 2014 Elsevier B.V. All rights reserved.

Febuxostat, an Inhibitor of Xanthine Oxidase, Suppresses Lipopolysaccharide-Induced MCP-1 Production via MAPK Phosphatase-1-Mediated Inactivation of JNK

PubMed Central

Nomura, Johji; Busso, Nathalie; Ives, Annette; Tsujimoto, Syunsuke; Tamura, Mizuho; So, Alexander; Yamanaka, Yoshihiro

2013-01-01

Excess reactive oxygen species (ROS) formation can trigger various pathological conditions such as inflammation, in which xanthine oxidase (XO) is one major enzymatic source of ROS. Although XO has been reported to play essential roles in inflammatory conditions, the molecular mechanisms underlying the involvement of XO in inflammatory pathways remain unclear. Febuxostat, a selective and potent inhibitor of XO, effectively inhibits not only the generation of uric acid but also the formation of ROS. In this study, therefore, we examined the effects of febuxostat on lipopolysaccharide (LPS)-mediated inflammatory responses. Here we show that febuxostat suppresses LPS-induced MCP-1 production and mRNA expression via activating MAPK phosphatase-1 (MKP-1) which, in turn, leads to dephosphorylation and inactivation of JNK in macrophages. Moreover, these effects of febuxostat are mediated by inhibiting XO-mediated intracellular ROS production. Taken together, our data suggest that XO mediates LPS-induced phosphorylation of JNK through ROS production and MKP-1 inactivation, leading to MCP-1 production in macrophages. These studies may bring new insights into the novel role of XO in regulating inflammatory process through MAPK phosphatase, and demonstrate the potential use of XO inhibitor in modulating the inflammatory processes. PMID:24086554

Formononetin, a phyto-oestrogen, and its metabolites up-regulate interleukin-4 production in activated T cells via increased AP-1 DNA binding activity

PubMed Central

Park, Jin; Kim, Seung H; Cho, Daeho; Kim, Tae S

2005-01-01

Phyto-oestrogens are polyphenolic non-steroidal plant compounds with oestrogen-like biological activity. Phyto-oestrogens have many biological effects including oestrogen agonist/antagonist properties. However, the effect of phyto-oestrogens on allergic responses remains unclear. In this study we investigated whether formononetin, a phyto-oestrogen, and its metabolites, daidzein and equol, affect production of interleukin-4 (IL-4), a pro-inflammatory cytokine closely associated with allergic immune response, in primary CD4+ T cells and EL4 T lymphoma cells. Formononetin, daidzein and equol significantly enhanced IL-4 production from both CD4+ T cells and EL4 cells in a dose-dependent manner. Formononetin, daidzein and equol also enhanced IL-4 gene promoter activity in EL4 cells transiently transfected with IL-4 gene promoter constructs, but this effect was impaired in EL4 cells transfected with an IL-4 promoter construct deleted of P4 site carrying nuclear factor of activated T cells (NF-AT) and activator protein-1 (AP-1) binding sites. In addition, formononetin, daidzein and equol increased AP-1 DNA binding activities while did not affect NF-AT DNA binding activities. The enhancing effects on IL-4 production and AP-1 DNA binding activities were abrogated by specific inhibitors for phosphatidylinositol-3-kinase (PI3K), protein kinase C (PKC) and p38 mitogen-activated protein kinase (MAPK), indicating that formononetin, daidzein and equol might enhance IL-4 production by increased activation of AP-1 through the PI3-K/PKC/p38 MAPK signalling pathway. These results suggest that phyto-oestrogens and some of their metabolites may increase allergic responses via the enhancement of IL-4 production in T cells. PMID:16108819

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

PubMed Central

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

2017-01-01

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

Intracellular signals mediating the food intake suppressive effects of hindbrain glucagon-like-peptide-1 receptor activation

PubMed Central

Hayes, Matthew R.; Leichner, Theresa M.; Zhao, Shiru; Lee, Grace S.; Chowansky, Amy; Zimmer, Derek; De Jonghe, Bart C.; Kanoski, Scott E.; Grill, Harvey J.; Bence, Kendra K.

2011-01-01

Summary Glucagon-like-peptide-1 receptor (GLP-1R) activation within the nucleus tractus solitarius (NTS) suppresses food intake and body weight (BW), but the intracellular signals mediating these effects are unknown. Here, hindbrain (4th icv) GLP-1R activation by Exendin-4 increased PKA and MAPK activity and decreased phosphorylation of AMPK in NTS. PKA and MAPK signaling contribute to food intake and BW suppression by Exendin-4, as inhibitors RpcAMP and U0126 (4th icv), respectively, attenuated Exendin-4's effects. Hindbrain GLP-1R activation inhibited feeding by reducing meal number, not meal size. This effect was attenuated with stimulation of AMPK activity by AICAR (4th icv). The PKA, MAPK and AMPK signaling responses by Ex-4 were present in immortalized GLP-1R-expressing neurons (GT1-7). In conclusion, hindbrain GLP-1R activation suppresses food intake and BW through coordinated PKA-mediated suppression of AMPK and activation of MAPK. Pharmacotherapies targeting these signaling pathways, which mediate intake-suppressive effects of CNS GLP-1R activation, may prove efficacious in treating obesity. PMID:21356521

Ampelopsin-induced reactive oxygen species enhance the apoptosis of colon cancer cells by activating endoplasmic reticulum stress-mediated AMPK/MAPK/XAF1 signaling

PubMed Central

Park, Ga Bin; Jeong, Jee-Yeong; Kim, Daejin

2017-01-01

Ampelopsin (Amp) is bioactive natural product and exerts anti-cancer effects against several cancer types. The present study investigated the anti-colon cancer activity of Amp and explored its mechanism of action. The treatment of colon cancer cells with Amp resulted in the dose- and time-dependent induction of apoptosis via the activation of endoplasmic reticulum (ER) stress, 5′ adenosine monophosphate-activated protein kinase (AMPK), and c-Jun N-terminal protein kinase (JNK)/p38 mitogen-activated protein kinases (MAPKs). Salubrinal, an ER stress inhibitor, prevented the upregulation of ER stress-associated proteins, including phosphorylated protein kinase RNA-like ER kinase, phosphorylated eukaryotic translation initiation factor 2α, glucose-regulated protein 78, and CCAAT/enhancer-binding protein homologous protein, as well as suppressing AMPK activation and the MAPK signaling pathway. Knockdown of AMPK by RNA interference failed to block ER stress. Additionally, SP600125 (a JNK inhibitor) and SB203580 (a p38-MAPK inhibitor) effectively inhibited apoptosis and attenuated the expression of X-linked IAP-associated factor 1 (XAF1) and apoptotic Bcl-2 family proteins (BCL2 antagonist/killer 1 and BCL2-associated X protein) in Amp-treated colon cancer cells. Furthermore, reactive oxygen species (ROS)-mediated ER stress/AMPK apoptotic signaling pathway in Amp-treated colon cancer cells were markedly inhibited by treatment with N-acetyl-L-cysteine, a ROS scavenger. These results demonstrate that treatment with Amp induces the apoptotic death of colon cancer cells through ER stress-initiated AMPK/MAPK/XAF1 signaling. These results also provide experimental information for developing Amp as therapeutic drug against colon cancer. PMID:29250183

Activation and Function of the MAPKs and Their Substrates, the MAPK-Activated Protein Kinases

PubMed Central

Cargnello, Marie; Roux, Philippe P.

2011-01-01

Summary: The mitogen-activated protein kinases (MAPKs) regulate diverse cellular programs by relaying extracellular signals to intracellular responses. In mammals, there are more than a dozen MAPK enzymes that coordinately regulate cell proliferation, differentiation, motility, and survival. The best known are the conventional MAPKs, which include the extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun amino-terminal kinases 1 to 3 (JNK1 to -3), p38 (α, β, γ, and δ), and ERK5 families. There are additional, atypical MAPK enzymes, including ERK3/4, ERK7/8, and Nemo-like kinase (NLK), which have distinct regulation and functions. Together, the MAPKs regulate a large number of substrates, including members of a family of protein Ser/Thr kinases termed MAPK-activated protein kinases (MAPKAPKs). The MAPKAPKs are related enzymes that respond to extracellular stimulation through direct MAPK-dependent activation loop phosphorylation and kinase activation. There are five MAPKAPK subfamilies: the p90 ribosomal S6 kinase (RSK), the mitogen- and stress-activated kinase (MSK), the MAPK-interacting kinase (MNK), the MAPK-activated protein kinase 2/3 (MK2/3), and MK5 (also known as p38-regulated/activated protein kinase [PRAK]). These enzymes have diverse biological functions, including regulation of nucleosome and gene expression, mRNA stability and translation, and cell proliferation and survival. Here we review the mechanisms of MAPKAPK activation by the different MAPKs and discuss their physiological roles based on established substrates and recent discoveries. PMID:21372320

LeMAPK1, LeMAPK2, and LeMAPK3 are associated with nitric oxide-induced defense response against Botrytis cinerea in the Lycopersicon esculentum fruit.

PubMed

Zheng, Yanyan; Hong, Hui; Chen, Lin; Li, Jingyuan; Sheng, Jiping; Shen, Lin

2014-02-12

Nitric oxide (NO) and mitogen-activated protein kinases (MAPKs) are signal molecules involved in the disease resistance of plants. To investigate the role of tomato MAPKs in the NO-mediated defense response, mature green tomatoes (Lycopersicon esculentum Mill. cv. Qian-xi) were treated with a MAPKs inhibitor (1,4-diamino-2,3-dicyano-1,4-bis(o-amino-phenylmercapto) butadiene (U0126)), NO donor sodium nitroprusside (SNP), and SNP plus U0126. Treatment with U0126 increased the incidence of disease and size of lesion areas in the tomato fruits after being inoculated with Botrytis cinerea. NO enhanced the resistance of the tomato fruits against Botrytis cinerea invasion and the activities of nitric oxide synthase, Chitinase, β-1,3-glucanase, polyphenol oxidase, and phenylalanine ammonia-lyase. However, the effects of NO on disease resistance were weakened by the MAPKs inhibitor. Meanwhile, the relative expression of LeMAPK1, LeMAPK2, and LeMAPK3 in the (SNP + U0126)-treated fruits was lower than that in the SNP-treated fruits. The results suggest that LeMAPK1/2/3 are involved in NO-induced disease resistance of tomato fruits against Botrytis cinerea.

Effects of environmental estrogenic chemicals on AP1 mediated transcription with estrogen receptors alpha and beta.

PubMed

Fujimoto, Nariaki; Honda, Hiroaki; Kitamura, Shigeyuki

2004-01-01

There has been much discussion concerning endocrine disrupting chemicals suspected of exerting adverse effects in both wildlife and humans. Since the majority of these compounds are estrogenic, a large number of in vitro tests for estrogenic characteristics have been developed for screening purpose. One reliable and widely used method is the reporter gene assay employing estrogen receptors (ERs) and a reporter gene with a cis-acting estrogen responsive element (ERE). Other elements such as AP1 also mediate estrogenic signals and the manner of response could be quite different from that of ERE. Since this has yet to be explored, the ER mediated AP1 activity in response to a series of environmental estrogens was investigated in comparison with ERE findings. All the compounds exhibited estrogenic properties with ERE-luc and their AP1 responses were quite similar. These was one exception, however, p,p'-DDT (1,1,1,-trichloro-2,2-bis(p-chlorophenyl)ethane) did not exert any AP1-luc activity, while it appeared to be estrogenic at 10(-7) to 10(-5)M with the ERE action. None of the compounds demonstrated ER beta:AP1 activity. These data suggest that significant differences can occur in responses through the two estrogen pathways depending on environmental chemicals.

Monocyte 15-Lipoxygenase Gene Expression Requires ERK1/2 MAPK Activity

PubMed Central

Bhattacharjee, Ashish; Mulya, Anny; Pal, Srabani; Roy, Biswajit; Feldman, Gerald M.; Cathcart, Martha K.

2011-01-01

IL-13 induces profound expression of 15-lipoxygenase (15-LO) in primary human monocytes. Our studies have defined the functional IL-13R complex, association of Jaks with the receptor components, and the tyrosine phosphorylation of several Stat molecules in response to IL-13. Furthermore, we identified both p38MAPK and protein kinase Cδ as critical regulators of 15-LO expression. In this study, we report an ERK1/2-dependent signaling cascade that regulates IL-13–mediated 15-LO gene expression. We show the rapid phosphorylation/activation of ERK1/2 upon IL-13 exposure. Our results indicate that Tyk2 kinase is required for the activation of ERK1/2, which is independent of the Jak2, p38MAPK, and protein kinase Cδ pathways, suggesting bifurcating parallel regulatory pathways downstream of the receptor. To investigate the signaling mechanisms associated with the ERK1/2-dependent expression of 15-LO, we explored the involvement of transcription factors, with predicted binding sites in the 15-LO promoter, in this process including Elk1, early growth response-1 (Egr-1), and CREB. Our findings indicate that IL-13 induces Egr-1 nuclear accumulation and CREB serine phosphorylation and that both are markedly attenuated by inhibition of ERK1/2 activity. We further show that ERK1/2 activity is required for both Egr-1 and CREB DNA binding to their cognate sequences identified within the 15-LO promoter. Furthermore, by transfecting monocytes with the decoy oligodeoxyribonucleotides specific for Egr-1 and CREB, we discovered that Egr-1 and CREB are directly involved in regulating 15-LO gene expression. These studies characterize an important regulatory role for ERK1/2 in mediating IL-13–induced monocyte 15-LO expression via the transcription factors Egr-1 and CREB. PMID:20861348

Monocyte 15-lipoxygenase gene expression requires ERK1/2 MAPK activity.

PubMed

Bhattacharjee, Ashish; Mulya, Anny; Pal, Srabani; Roy, Biswajit; Feldman, Gerald M; Cathcart, Martha K

2010-11-01

IL-13 induces profound expression of 15-lipoxygenase (15-LO) in primary human monocytes. Our studies have defined the functional IL-13R complex, association of Jaks with the receptor components, and the tyrosine phosphorylation of several Stat molecules in response to IL-13. Furthermore, we identified both p38MAPK and protein kinase Cδ as critical regulators of 15-LO expression. In this study, we report an ERK1/2-dependent signaling cascade that regulates IL-13-mediated 15-LO gene expression. We show the rapid phosphorylation/activation of ERK1/2 upon IL-13 exposure. Our results indicate that Tyk2 kinase is required for the activation of ERK1/2, which is independent of the Jak2, p38MAPK, and protein kinase Cδ pathways, suggesting bifurcating parallel regulatory pathways downstream of the receptor. To investigate the signaling mechanisms associated with the ERK1/2-dependent expression of 15-LO, we explored the involvement of transcription factors, with predicted binding sites in the 15-LO promoter, in this process including Elk1, early growth response-1 (Egr-1), and CREB. Our findings indicate that IL-13 induces Egr-1 nuclear accumulation and CREB serine phosphorylation and that both are markedly attenuated by inhibition of ERK1/2 activity. We further show that ERK1/2 activity is required for both Egr-1 and CREB DNA binding to their cognate sequences identified within the 15-LO promoter. Furthermore, by transfecting monocytes with the decoy oligodeoxyribonucleotides specific for Egr-1 and CREB, we discovered that Egr-1 and CREB are directly involved in regulating 15-LO gene expression. These studies characterize an important regulatory role for ERK1/2 in mediating IL-13-induced monocyte 15-LO expression via the transcription factors Egr-1 and CREB.

Mechanism of salutary effects of melatonin-mediated liver protection after trauma-hemorrhage: p38 MAPK-dependent iNOS/HIF-1α pathway.

PubMed

Hsu, Jun-Te; Le, Puo-Hsien; Lin, Chun-Jung; Chen, Tsung-Hsing; Kuo, Chia-Jung; Chiang, Kun-Chun; Yeh, Ta-Sen

2017-05-01

Although melatonin attenuates the increases in inflammatory mediators and reduces organ injury during trauma-hemorrhage, the mechanisms remain unclear. This study explored whether melatonin prevents liver injury after trauma-hemorrhage through the p38 mitogen-activated protein kinase (MAPK)-dependent, inducible nitrite oxide (iNOS)/hypoxia-inducible factor (HIF)-1α pathway. After a 5-cm midline laparotomy, male rats underwent hemorrhagic shock (mean blood pressure ~40 mmHg for 90 min) followed by fluid resuscitation. At the onset of resuscitation, rats were treated with vehicle, melatonin (2 mg/kg), melatonin plus p38 MAPK inhibitor SB203580 (2 mg/kg), or melatonin plus the melatonin receptor antagonist luzindole (2.5 mg/kg). At 2 h after trauma-hemorrhage, histopathology score of liver injury, liver tissue myeloperoxidase activity, malondialdehyde, adenosine triphosphate, serum alanine aminotransferase, and asparate aminotransferase levels were significantly increased compared with sham-operated control. Trauma-hemorrhage resulted in a significant decrease in the p38 MAPK activation compared with that in the sham-treated animals. Administration of melatonin after trauma-hemorrhage normalized liver p38 MAPK phosphorylation and iNOS and HIF-1α expression and attenuated cleaved caspase 3 and receptor interacting protein kinase-1 levels. Coadministration of SB203580 or luzindole abolished the melatonin-mediated attenuation of the trauma-hemorrhage-induced increase of iNOS/HIF-1α protein expression and liver injury markers. Taken together, our results suggest that melatonin prevents trauma-hemorrhage-induced liver injury in rats, at least in part, through melatonin receptor-related, p38 MAPK-dependent iNOS/HIF-1α pathway. NEW & NOTEWORTHY Trauma-hemorrhage resulted in a significant decrease in liver p38 MAPK activation and increase in nitrite oxide synthase (iNOS) and hypoxia-inducible factor (HIF)-1α expression. Administration of melatonin after trauma

Lipopolysaccharide potentiates the effect of hepatocyte growth factor on hepatocyte replication in rats by augmenting AP-1 activity.

PubMed

Gao, C; Jokerst, R; Gondipalli, P; Cai, S R; Kennedy, S; Flye, M W; Ponder, K P

1999-12-01

The liver regenerates by replication of differentiated hepatocytes after damage or removal of part of the liver. Although several growth factors and signaling pathways are activated during regeneration, it is unclear as to which of these are essential for hepatocyte replication. We show here that low- (1 mg/kg) and high- (10 mg/kg) dose hepatocyte growth factor (HGF) induced replication of 2.1% and 11.1% of hepatocytes in rats, respectively. Lipopolysaccharide (LPS), an inducer of the acute phase response, augmented hepatocyte replication in response to low- and high-dose HGF by 4- and 2-fold, respectively. HGF alone induced moderate levels of c-Jun-N-terminal kinase (JNK) and p44/p42 mitogen-activated protein kinase (MAPK), resulting in moderate levels of AP-1-DNA binding activity. The combination of LPS + HGF increased JNK and AP-1-DNA binding activity more than levels seen with LPS or HGF alone. The activation of Stat3 that was observed after administration of LPS + HGF, but not HGF alone, could contribute to increased transcription of AP-1 components. Because phosphorylation of the c-Jun component of AP-1 by JNK increases its ability to activate transcription, the AP-1 in hepatocytes from animals treated with LPS + HGF may be more active than in rats treated with LPS or HGF alone. LPS may contribute to hepatocyte replication by potentiating the effect of HGF on the activation of both AP-1-DNA binding and transcriptional activity.

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.

OsCERK1-Mediated Chitin Perception and Immune Signaling Requires Receptor-like Cytoplasmic Kinase 185 to Activate an MAPK Cascade in Rice.

PubMed

Wang, Chao; Wang, Gang; Zhang, Chi; Zhu, Pinkuan; Dai, Huiling; Yu, Nan; He, Zuhua; Xu, Ling; Wang, Ertao

2017-04-03

Conserved pathogen-associated molecular patterns (PAMPs), such as chitin, are perceived by pattern recognition receptors (PRRs) located at the host cell surface and trigger rapid activation of mitogen-activated protein kinase (MAPK) cascades, which are required for plant resistance to pathogens. However, the direct links from PAMP perception to MAPK activation in plants remain largely unknown. In this study, we found that the PRR-associated receptor-like cytoplasmic kinase Oryza sativa RLCK185 transmits immune signaling from the PAMP receptor OsCERK1 to an MAPK signaling cascade through interaction with an MAPK kinase kinase, OsMAPKKKε, which is the initial kinase of the MAPK cascade. OsRLCK185 interacts with and phosphorylates the C-terminal regulatory domain of OsMAPKKKε. Coexpression of phosphomimetic OsRLCK185 and OsMAPKKKε activates MAPK3/6 phosphorylation in Nicotiana benthamiana leaves. Moreover, OsMAPKKKε interacts with and phosphorylates OsMKK4, a key MAPK kinase that transduces the chitin signal. Overexpression of OsMAPKKKε increases chitin-induced MAPK3/6 activation, whereas OsMAPKKKε knockdown compromises chitin-induced MAPK3/6 activation and resistance to rice blast fungus. Taken together, our results suggest the existence of a phospho-signaling pathway from cell surface chitin perception to intracellular activation of an MAPK cascade in rice. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

COMP-angiopoietin 1 increases proliferation, differentiation, and migration of stem-like cells through Tie-2-mediated activation of p38 MAPK and PI3K/Akt signal transduction pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kook, Sung-Ho; Lim, Shin-Saeng; Cho, Eui-Sic

2014-12-12

Highlights: • COMP-Ang1 induces Tie-2 activation in BMMSCs, but not in primary osteoblasts. • Tie-2 knockdown inhibits COMP-Ang1-stimulated proliferation and osteoblastogenesis. • Tie-2 knockdown prevents COMP-Ang1-induced activation of PI3K/Akt and p38 MAPK. • COMP-Ang1 induces migration of cells via activation of PI3K/Akt and CXCR4 pathways. • COMP-Ang1 stimulates in vivo migration of PDLSCs into a calvarial defect site of rats. - Abstract: Recombinant COMP-Ang1, a chimera of angiopoietin-1 (Ang1) and a short coiled-coil domain of cartilage oligomeric matrix protein (COMP), is under consideration as a therapeutic agent capable of inducing the homing of cells with increased angiogenesis. However, the potentialsmore » of COMP-Ang1 to stimulate migration of mesenchymal stem cells (MSCs) and the associated mechanisms are not completely understood. We examined the potential of COMP-Ang1 on bone marrow (BM)-MSCs, human periodontal ligament stem cells (PDLSCs), and calvarial osteoblasts. COMP-Ang1 augmented Tie-2 induction at protein and mRNA levels and increased proliferation and expression of runt-related transcription factor 2 (Runx2), osterix, and CXCR4 in BMMSCs, but not in osteoblasts. The COMP-Ang1-mediated increases were inhibited by Tie-2 knockdown and by treating inhibitors of phosphoinositide 3-kinase (PI3K), LY294002, or p38 mitogen-activated protein kinase (MAPK), SB203580. Phosphorylation of p38 MAPK and Akt was prevented by siRNA-mediated silencing of Tie-2. COMP-Ang1 also induced in vitro migration of BMMSCs and PDLSCs. The induced migration was suppressed by Tie-2 knockdown and by CXCR4-specific peptide antagonist or LY294002, but not by SB203580. Furthermore, COMP-Ang1 stimulated the migration of PDLSCs into calvarial defect site of rats. Collectively, our results demonstrate that COMP-Ang1-stimulated proliferation, differentiation, and migration of progenitor cells may involve the Tie-2-mediated activation of p38 MAPK and PI3K/Akt pathways.« less

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

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

PubMed

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

2016-02-08

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

SPAK kinase is a substrate and target of PKCθ in T-cell receptor-induced AP-1 activation pathway

PubMed Central

Li, Yingqiu; Hu, Junru; Vita, Randi; Sun, Binggang; Tabata, Hiroki; Altman, Amnon

2004-01-01

Protein kinase C-θ (PKCθ) plays an important role in T-cell activation via stimulation of AP-1 and NF-κB. Here we report the isolation of SPAK, a Ste20-related upstream mitogen-activated protein kinase (MAPK), as a PKCθ-interacting kinase. SPAK interacted with PKCθ (but not with PKCα) via its 99 COOH-terminal residues. TCR/CD28 costimulation enhanced this association and stimulated the catalytic activity of SPAK. Recombinant SPAK was phosphorylated on Ser-311 in its kinase domain by PKCθ, but not by PKCα. The magnitude and duration of TCR/CD28-induced endogenous SPAK activation were markedly impaired in PKCθ-deficient T cells. Transfected SPAK synergized with constitutively active PKCθ to activate AP-1, but not NF-κB. This synergistic activity, as well as the receptor-induced SPAK activation, required the PKCθ-interacting region of SPAK, and Ser-311 mutation greatly reduced these activities of SPAK. Conversely, a SPAK-specific RNAi or a dominant-negative SPAK mutant inhibited PKCθ- and TCR/CD28-induced AP-1, but not NF-κB, activation. These results define SPAK as a substrate and target of PKCθ in a TCR/CD28-induced signaling pathway leading selectively to AP-1 (but not NF-κB) activation. PMID:14988727

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Youn, Gi Soo; Kwon, Dong-Joo; Ju, Sung Mi

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, celastrolmore » 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.« less

Effects of Curcumin on Tobacco Smoke-induced Hepatic MAPK Pathway Activation and Epithelial-Mesenchymal Transition In Vivo.

PubMed

Liang, Zhaofeng; Wu, Rui; Xie, Wei; Xie, Chunfeng; Wu, Jieshu; Geng, Shanshan; Li, Xiaoting; Zhu, Mingming; Zhu, Weiwei; Zhu, Jianyun; Huang, Cong; Ma, Xiao; Xu, Wenrong; Zhong, Caiyun; Han, Hongyu

2017-08-01

Tobacco smoke is a major risk factor for hepatic cancer. Epithelial-mesenchymal transition (EMT) induced by tobacco smoke is crucially involved in the initiation and development of cancer. Mitogen-activated protein kinase (MAPK) pathways play important roles in tobacco smoke-associated carcinogenesis including EMT process. The chemopreventive effect of curcumin supplementation against cancers has been reported. In this study, we investigated the effects of tobacco smoke on MAPK pathway activation and EMT alterations, and then the preventive effect of curcumin was examined in the liver of BALB/c mice. Our results indicated that exposure of mice to tobacco smoke for 12 weeks led to activation of ERK1/2, JNK, p38 and ERK5 pathways as well as activator protein-1 (AP-1) proteins in liver tissue. Exposure of mice to tobacco smoke reduced the hepatic mRNA and protein expression of the epithelial markers, while the hepatic mRNA and protein levels of the mesenchymal markers were increased. Treatment of curcumin effectively attenuated tobacco smoke-induced activation of ERK1/2 and JNK MAPK pathways, AP-1 proteins and EMT alterations in the mice liver. Our data suggested the protective effect of curcumin in tobacco smoke-triggered MAPK pathway activation and EMT in the liver of BALB/c mice, thus providing new insights into the chemoprevention of tobacco smoke-associated hepatic cancer. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

The frequencies of calcium oscillations are optimized for efficient calcium-mediated activation of Ras and the ERK/MAPK cascade.

PubMed

Kupzig, Sabine; Walker, Simon A; Cullen, Peter J

2005-05-24

Ras proteins are binary switches that, by cycling through inactive GDP- and active GTP-bound conformations, regulate multiple cellular signaling pathways, including those that control growth and differentiation. For some time, it has been known that receptor-mediated increases in the concentration of intracellular free calcium ([Ca(2+)](i)) can modulate Ras activation. Increases in [Ca(2+)](i) often occur as repetitive Ca(2+) spikes or oscillations. Induced by electrical or receptor stimuli, these repetitive Ca(2+) oscillations increase in frequency with the amplitude of receptor stimuli, a phenomenon critical for the induction of selective cellular functions. Here, we show that Ca(2+) oscillations are optimized for Ca(2+)-mediated activation of Ras and signaling through the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) cascade. We present additional evidence that Ca(2+) oscillations reduce the effective Ca(2+) threshold for the activation of Ras and that the oscillatory frequency is optimized for activation of Ras and the ERK/MAPK pathway. Our results describe a hitherto unrecognized link between complex Ca(2+) signals and the modulation of the Ras/ERK/MAPK signaling cascade.

AP-1/σ1B-adaptin mediates endosomal synaptic vesicle recycling, learning and memory

PubMed Central

Glyvuk, Nataliya; Tsytsyura, Yaroslav; Geumann, Constanze; D'Hooge, Rudi; Hüve, Jana; Kratzke, Manuel; Baltes, Jennifer; Böning, Daniel; Klingauf, Jürgen; Schu, Peter

2010-01-01

Synaptic vesicle recycling involves AP-2/clathrin-mediated endocytosis, but it is not known whether the endosomal pathway is also required. Mice deficient in the tissue-specific AP-1–σ1B complex have impaired synaptic vesicle recycling in hippocampal synapses. The ubiquitously expressed AP-1–σ1A complex mediates protein sorting between the trans-Golgi network and early endosomes. Vertebrates express three σ1 subunit isoforms: A, B and C. The expressions of σ1A and σ1B are highest in the brain. Synaptic vesicle reformation in cultured neurons from σ1B-deficient mice is reduced upon stimulation, and large endosomal intermediates accumulate. The σ1B-deficient mice have reduced motor coordination and severely impaired long-term spatial memory. These data reveal a molecular mechanism for a severe human X-chromosome-linked mental retardation. PMID:20203623

Polydatin ameliorates Staphylococcus aureus-induced mastitis in mice via inhibiting TLR2-mediated activation of the p38 MAPK/NF-κB pathway.

PubMed

Jiang, Kang-Feng; Zhao, Gan; Deng, Gan-Zhen; Wu, Hai-Chong; Yin, Nan-Nan; Chen, Xiu-Ying; Qiu, Chang-Wei; Peng, Xiu-Li

2017-02-01

Recent studies show that Polydatin (PD) extracted from the roots of Polygonum cuspidatum Sieb, a widely used traditional Chinese remedies, possesses anti-inflammatory activity in several experimental models. In this study, we investigated the anti-inflammatory effects of PD on Staphylococcus aureus-induced mastitis in mice and elucidated the potential mechanisms. In mice with S aureus-induced mastitis, administration of PD (15, 30, 45 mg/kg, ip) or dexamethasone (Dex, 5 mg/kg, ip) significantly suppressed the infiltration of inflammatory cells, ameliorated the mammary structural damage, and inhibited the activity of myeloperoxidase, a biomarker of neutrophils accumulation. Furthermore, PD treatment dose-dependently decreased the levels of TNF-α, IL-1β, IL-6 and IL-8 in the mammary gland tissues. PD treatment also dose-dependently decreased the expression of TLR2, MyD88, IRAK1, IRAK4 and TRAF6 as well as the phosphorylation of TAK1, MKK3/6, p38 MAPK, IκB-α and NF-κB in the mammary gland tissues. In mouse mammary epithelial cells (mMECs) infected by S aureus in vitro, pretreatment with PD dose-dependently suppressed the upregulated pro-inflammatory cytokines and signaling proteins, and the nuclear translocation of NF-κB p65 and AP-1. A TLR2-neutralizing antibody mimicked PD in its suppression on S aureus-induced upregulation of MyD88, p-p38 and p-p65 levels in mMECs. PD (50, 100 μg/mL) affected neither the growth of S aureus in vitro, nor the viability of mMECs. In conclusion, PD does not exhibit antibacterial activity against S aureus, its therapeutic effects in mouse S aureus-induced mastitis depend on its ability to down-regulate pro-inflammatory cytokine levels via inhibiting TLR2-mediated activation of the p38 MAPK/NF-κB signaling pathway.

Potentiation of Schaffer-Collateral CA1 Synaptic Transmission by eEF2K and p38 MAPK Mediated Mechanisms.

PubMed

Weng, Weiguang; Chen, Ying; Wang, Man; Zhuang, Yinghan; Behnisch, Thomas

2016-01-01

The elongation factor 2 kinase (eEF2K), likewise known as CaMKIII, has been demonstrated to be involved in antidepressant responses of NMDA receptor antagonists. Even so, it remains open whether direct inhibition of eEF2K without altering up-stream or other signaling pathways affects hippocampal synaptic transmission and neuronal network synchrony. Inhibition of eEF2K by the selective and potent eEF2K inhibitor A-484954 induced a fast pre-synaptically mediated enhancement of synaptic transmission and synchronization of neural network activity. The eEF2K-inhibition mediated potentiation of synaptic transmission of hippocampal CA1 neurons is most notably independent of protein synthesis and does not rely on protein kinase C, protein kinase A or mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase 1/2. Moreover, the strengthening of synaptic transmission in the response to the inhibition of eEF2K was strongly attenuated by the inhibition of p38 MAPK. In addition, we show the involvement of barium-sensitive and more specific the TWIK-related potassium-1 (TREK-1) channels in the eEF2K-inhibition mediated potentiation of synaptic transmission. These findings reveal a novel pathway of eEF2K mediated regulation of hippocampal synaptic transmission. Further research is required to study whether such compounds could be beneficial for the development of mood disorder treatments with a fast-acting antidepressant response.

Sulforaphane attenuates microglia-mediated neuronal necroptosis through down-regulation of MAPK/NF-κB signaling pathways in LPS-activated BV-2 microglia.

PubMed

Qin, Sisi; Yang, Canhong; Huang, Weihua; Du, Shuhua; Mai, Hantao; Xiao, Jijie; Lü, Tianming

2018-01-31

Sulforaphane (SFN), a natural dietary isothiocyanate in cruciferous vegetables such as broccoli and cabbage, has very strong anti-inflammatory activity. Activation of microglia leads to overexpression of a series of pro-inflammatory mediators, which play a vital role in neuronal damage. SFN may have neuroprotective effects in different neurodegenerative diseases related to inflammation. However, the mechanisms underlying SFN's protection of neurons against microglia-mediated neuronal damage are not fully understood. Here, we investigated how SFN attenuated microglia-mediated neuronal damage. Our results showed that SFN could not directly protect the viability of neurons following pro-inflammatory mediators, but increased the viability of BV-2 microglia and down-regulated the mRNA and protein levels of pro-inflammatory mediators including TNF-α, IL-1β, IL-6 and iNOS in a concentration-dependent manner in BV-2 cells. SFN also significantly blocked the phosphorylation of MAPKs (p38, JNK, and ERK1/2) and NF-κB p65, both by itself and with MAPK inhibitors (SB203580, SP 600125, and U0126) or an NF-κB inhibitor (PDTC). The expression of pro-inflammatory proteins was also blocked by SFN with or without inhibitors. Further, SFN indirectly increased the viability and maintained the morphology of neurons, and the protein expression of RIPK3 and MLKL was significantly suppressed by SFN in neuronal necroptosis through p38, JNK, and NF-κB p65 but not ERK1/2 signaling pathways. Together, our results demonstrate that SFN attenuates LPS-induced pro-inflammatory responses through down-regulation of MAPK/NF-κB signaling pathway in BV-2 microglia and thus indirectly suppresses microglia-mediated neuronal damage. Copyright © 2018 Elsevier Ltd. All rights reserved.

Aerosol-delivered programmed cell death 4 enhanced apoptosis, controlled cell cycle and suppressed AP-1 activity in the lungs of AP-1 luciferase reporter mice.

PubMed

Hwang, S-K; Jin, H; Kwon, J T; Chang, S-H; Kim, T H; Cho, C-S; Lee, K H; Young, M R; Colburn, N H; Beck, G R; Yang, H-S; Cho, M-H

2007-09-01

The long-term survival of lung cancer patients treated with conventional therapies remains poor and therefore the need for novel approaches remains high. This has led to the re-emergence of aerosol delivery as a therapeutic intervention. In this study, glucosylated polyethylenimine (GPEI) was used as carrier to investigate programmed cell death 4 (PDCD4) and PDCD4 mutant (D418A), an eIF4A-binding mutant, on PDCD4-related signaling and activator protein-1 (AP-1) activity in the lungs of AP-1 luciferase reporter mice. After confirming the efficiency of GPEI as a carrier in lungs, the effects of aerosol-delivered PDCD4 were investigated in AP-1 luciferase reporter mice. Aerosol delivery of GPEI/PDCD4 through a nose-only inhalation facilitated the apoptosis of lungs whereas aerosol PDCD4 mutant did not. Also, such aerosol delivery regulated proteins relevant to cell-cycle control and suppressed AP-1 activity. Results obtained by western blot analysis, immunohistochemistry, luciferase assay and deoxynucleotidyl-transferase-mediated nick end labeling study suggest that combined actions such as facilitating apoptosis, controlling cell cycle and suppression of AP-1 activity by PDCD4 may provide useful tool for designing lung tumor prevention and treatment by which PDCD4 functions as a transformation suppressor in the future.

Icariin and icaritin stimulate the proliferation of SKBr3 cells through the GPER1-mediated modulation of the EGFR-MAPK signaling pathway.

PubMed

Ma, Hai-Rong; Wang, Jie; Chen, Yiu-Fai; Chen, Hua; Wang, Wei-Shan; Aisa, Haji Akber

2014-06-01

Icariin (ICA) and icaritin (ICT), with a similar structure to genistein, are the important bioactive components of the genus Epimedium, and regulate many cellular processes. In the present study, using the estrogen receptor (ER)-negative breast cancer cell line, SKBr3, as a model, we examined the hypothesis that ICA and ICT at low concentrations stimulate SKBr3 cell proliferation in vitro through the functional membrane, G protein‑coupled estrogen receptor 1 (GPER1), mediated by the epithelial growth factor receptor (EGFR)‑mitogen-activated protein kinase (MAPK) signaling pathway. MTT assay revealed that ICA and ICT at doses of 1 nM to 1 µM markedly stimulated SKBr3 cell proliferation in a dose-dependent manner. The ICA- and ICT-stimulated cell growth was completely suppressed by the GPER1 antagonist, G-15, indicating that the ICA‑ and ICT-stimulated cell proliferation was mediated by GPER1 activation. Semi-quantitative RT-PCR analysis revealed that treatment with ICA and ICT enhanced the transcription of c-fos, a proliferation-related early gene. The ICA- and ICT-stimulated mRNA expression was markedly attenuated by G-15, AG-1478 (an EGFR antagonist) or PD98059 (a MAPK inhibitor). Our data also demonstrated that ICA and ICT increased the phosphorylation of ERK1/2. The ICA- and ICT-stimulated ERK1/2 phosphorylation was blocked by pre-treatment of the cells with G-15 and AG-1478 or PD 98059. Flow cytometric analysis confirmed that the ICA- and ICT-stimulated SKBr3 cell proliferation involved the GPER1-mediated modulation of the EGFR‑MAPK signaling pathway. To the best of our knowledge, our current findings demonstrate for the first time that ICA and ICT promote the progression of ER-negative breast cancer through the activation of membrane GPER1.

Dioscin alleviates BDL- and DMN-induced hepatic fibrosis via Sirt1/Nrf2-mediated inhibition of p38 MAPK pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gu, Lina; Tao, Xufeng; Xu, Youwei

Oxidative stress is involved in hepatic stellate cells (HSCs) activation and extracellular matrix overproduction. We previously reported the promising effects of dioscin against CCl{sub 4}-induced liver fibrosis, but its effects and mechanisms on BDL- and DMN-induced liver fibrosis remain unknown. The results in the present study indicated that dioscin significantly inhibited HSCs activation and attenuated hepatic fibrosis in rats. Furthermore, dioscin markedly up-regulated the levels of sirtuin 1 (Sirt1), HO-1, GST, GCLC and GCLM via increasing the nuclear translocation of nuclear erythroid factor 2-related factor 2 (Nrf2), which in turn inhibited mitogen-activated protein kinase 14 (p38 MAPK) phosphorylation and reducedmore » the levels of COL1A1, COL3A1, α-SMA and fibronectin. These results were further validated by knockdown of Sirt1 and Nrf2 using siRNAs silencing, and abrogation of p38 MAPK using SB-203580 (a p38 MAPK inhibitor) in HSC-T6 and LX-2 cells. Collectively, our findings confirmed the potent effects of dioscin against liver fibrosis and also provided novel insights into the mechanisms of this compound as a candidate for the prevention of liver fibrosis in the future. - Highlights: • Dioscin showed potent effects against BDL- and DMN-induced liver fibrosis in rats. • Dioscin significantly suppressed oxidative stress. • Dioscin triggered Sirt1/Nrf2-mediated inhibition of p38 MAPK pathway. • Dioscin should be developed as a novel candidate to treat liver fibrosis.« less

Dexamethasone inhibits IL-12p40 production in lipopolysaccharide-stimulated human monocytic cells by down-regulating the activity of c-Jun N-terminal kinase, the activation protein-1, and NF-kappa B transcription factors.

PubMed

Ma, Wei; Gee, Katrina; Lim, Wilfred; Chambers, Kelly; Angel, Jonathan B; Kozlowski, Maya; Kumar, Ashok

2004-01-01

IL-12 plays a critical role in the development of cell-mediated immune responses and in the pathogenesis of inflammatory and autoimmune disorders. Dexamethasone (DXM), an anti-inflammatory glucocorticoid, has been shown to inhibit IL-12p40 production in LPS-stimulated monocytic cells. In this study, we investigated the molecular mechanism by which DXM inhibits IL-12p40 production by studying the role of the mitogen-activated protein kinases (MAPKs), and the key transcription factors involved in human IL-12p40 production in LPS-stimulated monocytic cells. A role for c-Jun N-terminal kinase (JNK) MAPK in LPS-induced IL-12p40 regulation in a promonocytic THP-1/CD14 cell line was demonstrated by using specific inhibitors of JNK activation, SP600125 and a dominant-negative stress-activated protein/extracellular signal-regulated kinase kinase-1 mutant. To identify transcription factors regulating IL-12p40 gene transcription, extensive deletion analyses of the IL-12p40 promoter was performed. The results revealed the involvement of a sequence encompassing the AP-1-binding site, in addition to that of NF-kappaB. The role of AP-1 in IL-12p40 transcription was confirmed by using antisense c-fos and c-jun oligonucleotides. Studies conducted to understand the regulation of AP-1 and NF-kappaB activation by JNK MAPK revealed that both DXM and SP600125 inhibited IL-12p40 gene transcription by inhibiting the activation of AP-1 and NF-kappaB transcription factors as revealed by luciferase reporter and gel mobility shift assays. Taken together, our results suggest that DXM may inhibit IL-12p40 production in LPS-stimulated human monocytic cells by down-regulating the activation of JNK MAPK, the AP-1, and NF-kappaB transcription factors.

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

DOE PAGES

Nan, Xiaolin; Tamgüney, Tanja M.; Collisson, Eric A.; ...

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 KRas G12D, a mutant that constitutively binds GTP, activates MAPK. Overexpression of KRas leads to formation of higher order Ras nanoclusters. Conversely, at lower expression levels, KRas G12D 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

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

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

The Role of Activator Protein-1 (AP-1) Family Members in CD30-Positive Lymphomas

PubMed Central

Garces de los Fayos Alonso, Ines; Lagger, Sabine; Merkel, Olaf; Kenner, Lukas

2018-01-01

The Activator Protein-1 (AP-1) transcription factor (TF) family, composed of a variety of members including c-JUN, c-FOS and ATF, is involved in mediating many biological processes such as proliferation, differentiation and cell death. Since their discovery, the role of AP-1 TFs in cancer development has been extensively analysed. Multiple in vitro and in vivo studies have highlighted the complexity of these TFs, mainly due to their cell-type specific homo- or hetero-dimerization resulting in diverse transcriptional response profiles. However, as a result of the increasing knowledge of the role of AP-1 TFs in disease, these TFs are being recognized as promising therapeutic targets for various malignancies. In this review, we focus on the impact of deregulated expression of AP-1 TFs in CD30-positive lymphomas including Classical Hodgkin Lymphoma and Anaplastic Large Cell Lymphoma. PMID:29597249

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Eun Hee; Kim, Ji Young; Kim, Hyung-Kyun

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'-DDTmore » 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.« less

Stress-activated MAPKs and CRM1 regulate the subcellular localization of Net1A to control cell motility and invasion.

PubMed

Ulu, Arzu; Oh, Wonkyung; Zuo, Yan; Frost, Jeffrey A

2018-02-01

The neuroepithelial cell transforming gene 1A (Net1A, an isoform of Net1) is a RhoA subfamily guanine nucleotide exchange factor (GEF) that localizes to the nucleus in the absence of stimulation, preventing it from activating RhoA. Once relocalized in the cytosol, Net1A stimulates cell motility and extracellular matrix invasion. In the present work, we investigated mechanisms responsible for the cytosolic relocalization of Net1A. We demonstrate that inhibition of MAPK pathways blocks Net1A relocalization, with cells being most sensitive to JNK pathway inhibition. Moreover, activation of the JNK or p38 MAPK family pathway is sufficient to elicit Net1A cytosolic localization. Net1A relocalization stimulated by EGF or JNK activation requires nuclear export mediated by CRM1. JNK1 (also known as MAPK8) phosphorylates Net1A on serine 52, and alanine substitution at this site prevents Net1A relocalization caused by EGF or JNK activation. Glutamic acid substitution at this site is sufficient for Net1A relocalization and results in elevated RhoA signaling to stimulate myosin light chain 2 (MLC2, also known as MYL2) phosphorylation and F-actin accumulation. Net1A S52E expression stimulates cell motility, enables Matrigel invasion and promotes invadopodia formation. These data highlight a novel mechanism for controlling the subcellular localization of Net1A to regulate RhoA activation, cell motility, and invasion. © 2018. Published by The Company of Biologists Ltd.

Betulinic acid exerts anti-hepatitis C virus activity via the suppression of NF-κB- and MAPK-ERK1/2-mediated COX-2 expression.

PubMed

Lin, Chun-Kuang; Tseng, Chin-Kai; Chen, Kai-Hsun; Wu, Shih-Hsiung; Liaw, Chih-Chuang; Lee, Jin-Ching

2015-06-23

This study was designed to evaluate the effect of betulinic acid (BA), extracted from Avicennia marina, on the replication of hepatitis C virus (HCV) and to investigate the mechanism of this BA-mediated anti-HCV activity. HCV replicon and infectious systems were used to evaluate the anti-HCV activity of BA. Exogenous COX-2 or knock-down of COX-2 expression was used to investigate the role of COX-2 in the anti-HCV activity of BA. The effects of BA on the phosphorylation of NF-κB and on kinases in the MAPK signalling pathway were determined. The anti-HCV activity of BA in combination with other HCV inhibitors was also determined to assess its use as an anti-HCV supplement. BA inhibited HCV replication in both Ava5 replicon cells and in a cell culture-derived infectious HCV particle system. Treatment with a combination of BA and IFN-α, the protease inhibitor telaprevir or the NS5B polymerase inhibitor sofosbuvir resulted in the synergistic suppression of HCV RNA replication. Exogenous overexpression of COX-2 gradually attenuated the inhibitory effect of BA on HCV replication, suggesting that BA reduces HCV replication by suppressing the expression of COX-2. In particular, BA down-regulated HCV-induced COX-2 expression by reducing the phosphorylation of NF-κB and ERK1/2 of the MAPK signalling pathway. BA inhibits HCV replication by suppressing the NF-κB- and ERK1/2-mediated COX-2 pathway and may serve as a promising compound for drug development or as a potential supplement for use in the treatment of HCV-infected patients. © 2015 The British Pharmacological Society.

Power Frequency Magnetic Fields Affect the p38 MAPK-Mediated Regulation of NB69 Cell Proliferation Implication of Free Radicals.

PubMed

Martínez, María Antonia; Úbeda, Alejandro; Moreno, Jorge; Trillo, María Ángeles

2016-04-06

The proliferative response of the neuroblastoma line NB69 to a 100 µT, 50 Hz magnetic field (MF) has been shown mediated by activation of the MAPK-ERK1/2 pathway. This work investigates the MF effect on the cell cycle of NB69, the participation of p38 and c-Jun N-terminal (JNK) kinases in the field-induced proliferative response and the potential involvement of reactive oxygen species (ROS) in the activation of the MAPK-ERK1/2 and -p38 signaling pathways. NB69 cultures were exposed to the 100 µT MF, either intermittently for 24, 42 or 63 h, or continuously for periods of 15 to 120 min, in the presence or absence of p38 or JNK inhibitors: SB203580 and SP600125, respectively. Antioxidant N-acetylcysteine (NAC) was used as ROS scavenger. Field exposure induced transient activation of p38, JNK and ERK1/2. The MF proliferative effect, which was mediated by changes in the cell cycle, was blocked by the p38 inhibitor, but not by the JNK inhibitor. NAC blocked the field effects on cell proliferation and p38 activation, but not those on ERK1/2 activation. The MF-induced proliferative effects are exerted through sequential upregulation of MAPK-p38 and -ERK1/2 activation, and they are likely mediated by a ROS-dependent activation of p38.

p38 MAPK mediates fibrogenic signal through Smad3 phosphorylation in rat myofibroblasts.

PubMed

Furukawa, Fukiko; Matsuzaki, Koichi; Mori, Shigeo; Tahashi, Yoshiya; Yoshida, Katsunori; Sugano, Yasushi; Yamagata, Hideo; Matsushita, Masanori; Seki, Toshihito; Inagaki, Yutaka; Nishizawa, Mikio; Fujisawa, Junichi; Inoue, Kyoichi

2003-10-01

Hepatic stellate cells (HSCs) spontaneously transdifferentiate into myofibroblast (MFB)-phenotype on plastic dishes. This response recapitulates the features of activation in vivo. Transforming growth factor beta (TGF-beta) plays a prominent role in stimulating liver fibrogenesis by MFBs. In quiescent HSCs, TGF-beta signaling involves TGF-beta type I receptor (TbetaRI)-mediated phosphorylation of serine residues within the conserved SSXS motif at the C-terminus of Smad2 and Smad3. The middle linker regions of Smad2 and Smad3 also are phosphorylated by mitogen-activated protein kinase (MAPK). This study elucidates the change of Smad3-mediated signals during the transdifferentiation process. By using antibodies highly specific to the phosphorylated C-terminal region and the phosphorylated linker region of Smad3, we found that TGF-beta-dependent Smad3 phosphorylation at the C-terminal region decreased, but that the phosphorylation at the linker region increased in the process of transdifferentiation. TGF-beta activated the p38 MAPK pathway, further leading to Smad3 phosphorylation at the linker region in the cultured MFBs, irrespective of Smad2. The phosphorylation promoted hetero-complex formation and nuclear translocation of Smad3 and Smad4. Once combined with TbetaRI-phosphorylated Smad2, the Smad3 and Smad4 complex bound to plasminogen activator inhibitor-type I promoter could enhance the transcription. In addition, Smad3 phosphorylation mediated by the activated TbetaRI was impaired severely in MFBs during chronic liver injury, whereas Smad3 phosphorylation at the linker region was remarkably induced by p38 MAPK pathway. In conclusion, p38 MAPK-dependent Smad3 phosphorylation promoted extracellular matrix production in MFBs both in vitro and in vivo.

TLR4-NOX4-AP-1 signaling mediates lipopolysaccharide-induced CXCR6 expression in human aortic smooth muscle cells.

PubMed

Patel, Devang N; Bailey, Steven R; Gresham, John K; Schuchman, David B; Shelhamer, James H; Goldstein, Barry J; Foxwell, Brian M; Stemerman, Michael B; Maranchie, Jodi K; Valente, Anthony J; Mummidi, Srinivas; Chandrasekar, Bysani

2006-09-08

CXCL16 is a transmembrane non-ELR CXC chemokine that signals via CXCR6 to induce aortic smooth muscle cell (ASMC) proliferation. While bacterial lipopolysaccharide (LPS) has been shown to stimulate CXCL16 expression in SMC, its effects on CXCR6 are not known. Here, we demonstrate that LPS upregulates CXCR6 mRNA, protein, and surface expression in human ASMC. Inhibition of TLR4 with neutralizing antibodies or specific siRNA interference blocked LPS-mediated CXCR6 expression. LPS stimulated both AP-1 (c-Fos, c-Jun) and NF-kappaB (p50 and p65) activation, but only inhibition of AP-1 attenuated LPS-induced CXCR6 expression. Using dominant negative expression vectors and siRNA interference, we demonstrate that LPS induces AP-1 activation via MyD88, TRAF6, ERK1/2, and JNK signaling pathways. Furthermore, the flavoprotein inhibitor diphenyleniodonium chloride significantly attenuated LPS-mediated AP-1-dependent CXCR6 expression, as did inhibition of NOX4 NADPH oxidase by siRNA. Finally, CXCR6 knockdown inhibited CXCL16-induced ASMC proliferation. These results demonstrate that LPS-TLR4-NOX4-AP-1 signaling can induce CXCR6 expression in ASMC, and suggest that the CXCL16-CXCR6 axis may be an important proinflammatory pathway in the pathogenesis of atherosclerosis.

TLR4-NOX4-AP-1 signaling mediates lipopolysaccharide-induced CXCR6 expression in human aortic smooth muscle cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, Devang N.; Bailey, Steven R.; Gresham, John K.

2006-09-08

CXCL16 is a transmembrane non-ELR CXC chemokine that signals via CXCR6 to induce aortic smooth muscle cell (ASMC) proliferation. While bacterial lipopolysaccharide (LPS) has been shown to stimulate CXCL16 expression in SMC, its effects on CXCR6 are not known. Here, we demonstrate that LPS upregulates CXCR6 mRNA, protein, and surface expression in human ASMC. Inhibition of TLR4 with neutralizing antibodies or specific siRNA interference blocked LPS-mediated CXCR6 expression. LPS stimulated both AP-1 (c-Fos, c-Jun) and NF-{kappa}B (p50 and p65) activation, but only inhibition of AP-1 attenuated LPS-induced CXCR6 expression. Using dominant negative expression vectors and siRNA interference, we demonstrate thatmore » LPS induces AP-1 activation via MyD88, TRAF6, ERK1/2, and JNK signaling pathways. Furthermore, the flavoprotein inhibitor diphenyleniodonium chloride significantly attenuated LPS-mediated AP-1-dependent CXCR6 expression, as did inhibition of NOX4 NADPH oxidase by siRNA. Finally, CXCR6 knockdown inhibited CXCL16-induced ASMC proliferation. These results demonstrate that LPS-TLR4-NOX4-AP-1 signaling can induce CXCR6 expression in ASMC, and suggest that the CXCL16-CXCR6 axis may be an important proinflammatory pathway in the pathogenesis of atherosclerosis.« less

Plasmodium berghei MAPK1 Displays Differential and Dynamic Subcellular Localizations during Liver Stage Development

PubMed Central

Wierk, Jannika Katharina; Langbehn, Annette; Kamper, Maria; Richter, Stefanie; Burda, Paul-Christian; Heussler, Volker Theo; Deschermeier, Christina

2013-01-01

Mitogen-activated protein kinases (MAPKs) regulate key signaling events in eukaryotic cells. In the genomes of protozoan Plasmodium parasites, the causative agents of malaria, two genes encoding kinases with significant homology to other eukaryotic MAPKs have been identified (mapk1, mapk2). In this work, we show that both genes are transcribed during Plasmodium berghei liver stage development, and analyze expression and subcellular localization of the PbMAPK1 protein in liver stage parasites. Live cell imaging of transgenic parasites expressing GFP-tagged PbMAPK1 revealed a nuclear localization of PbMAPK1 in the early schizont stage mediated by nuclear localization signals in the C-terminal domain. In contrast, a distinct localization of PbMAPK1 in comma/ring-shaped structures in proximity to the parasite’s nuclei and the invaginating parasite membrane was observed during the cytomere stage of parasite development as well as in immature blood stage schizonts. The PbMAPK1 localization was found to be independent of integrity of a motif putatively involved in ATP binding, integrity of the putative activation motif and the presence of a predicted coiled-coil domain in the C-terminal domain. Although PbMAPK1 knock out parasites showed normal liver stage development, the kinase may still fulfill a dual function in both schizogony and merogony of liver stage parasites regulated by its dynamic and stage-dependent subcellular localization. PMID:23544094

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

PubMed

Shrestha, Y; Schafer, E J; Boehm, J S; Thomas, S R; He, F; Du, J; Wang, S; Barretina, J; Weir, B A; Zhao, J J; Polyak, K; Golub, T R; Beroukhim, R; Hahn, W C

2012-07-19

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 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 p21-activated kinase 1 (PAK1) as a kinase that permitted HMLE cells to form anchorage-independent colonies. PAK1 is amplified in several human cancer types, including 30--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.

Genistein regulates the IL-1 beta induced activation of MAPKs in human periodontal ligament cells through G protein-coupled receptor 30.

PubMed

Luo, Li-Jun; Liu, Feng; Lin, Zhi-Kai; Xie, Yu-Feng; Xu, Jia-Li; Tong, Qing-Chun; Shu, Rong

2012-06-01

Periodontal ligament (PDL) cells are fibroblasts that play key roles in tissue integrity, periodontal inflammation and tissue regeneration in the periodontium. The periodontal tissue destruction in periodontitis is mediated by host tissue-produced inflammatory cytokines, including interleukin-1β (IL-1β). Here, we report the expression of G protein-coupled receptor 30 (GPR30, also known as G protein-coupled estrogen receptor 1 GPER) in human PDL cells and its regulation by IL-1β. IL-1β-induced GPR30 expression in human PDL cells leads to the activation of multiple signaling pathways, including MAPK, NF-κB and PI3K. In contrast, genistein, an estrogen receptor ligand, postpones the activation of MAPKs induced by IL-1β. Moreover, the inhibition of GPR30 by G15, a GPR30-specific antagonist, eliminates this delay. Thus, genistein plays a role in the regulation of MAPK activation via GPR30, and GPR30 represents a novel target regulated by steroid hormones in PDL cells. Copyright © 2012 Elsevier Inc. All rights reserved.

Ghrelin accelerates wound healing through GHS-R1a-mediated MAPK-NF-κB/GR signaling pathways in combined radiation and burn injury in rats.

PubMed

Liu, Cong; Huang, Jiawei; Li, Hong; Yang, Zhangyou; Zeng, Yiping; Liu, Jing; Hao, Yuhui; Li, Rong

2016-06-07

The therapeutic effect of ghrelin on wound healing was assessed using a rat model of combined radiation and burn injury (CRBI). Rat ghrelin, anti-rat tumor necrosis factor (TNF) α polyclonal antibody (PcAb), or selective antagonists of p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK), and growth hormone secretagogue receptor (GHS-R) 1a (SB203580, SP600125, and [D-Lys3]-GHRP-6, respectively), were administered for seven consecutive days. Levels of various signaling molecules were assessed in isolated rat peritoneal macrophages. The results showed that serum ghrelin levels and levels of macrophage glucocorticoid receptor (GR) decreased, while phosphorylation of p38MAPK, JNK, and p65 nuclear factor (NF) κB increased. Ghrelin inhibited the serum induction of proinflammatory mediators, especially TNF-α, and promoted wound healing in a dose-dependent manner. Ghrelin treatment decreased phosphorylation of p38MAPK, JNK, and p65NF-κB, and increased GR levels in the presence of GHS-R1a. SB203580 or co-administration of SB203580 and SP600125 decreased TNF-α level, which may have contributed to the inactivation of p65NF-κB and increase in GR expression, as confirmed by western blotting. In conclusion, ghrelin enhances wound recovery in CRBI rats, possibly by decreasing the induction of TNF-α or other proinflammatory mediators that are involved in the regulation of GHS-R1a-mediated MAPK-NF-κB/GR signaling pathways.

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

Power Frequency Magnetic Fields Affect the p38 MAPK-Mediated Regulation of NB69 Cell Proliferation Implication of Free Radicals

PubMed Central

Martínez, María Antonia; Úbeda, Alejandro; Moreno, Jorge; Trillo, María Ángeles

2016-01-01

The proliferative response of the neuroblastoma line NB69 to a 100 µT, 50 Hz magnetic field (MF) has been shown mediated by activation of the MAPK-ERK1/2 pathway. This work investigates the MF effect on the cell cycle of NB69, the participation of p38 and c-Jun N-terminal (JNK) kinases in the field-induced proliferative response and the potential involvement of reactive oxygen species (ROS) in the activation of the MAPK-ERK1/2 and -p38 signaling pathways. NB69 cultures were exposed to the 100 µT MF, either intermittently for 24, 42 or 63 h, or continuously for periods of 15 to 120 min, in the presence or absence of p38 or JNK inhibitors: SB203580 and SP600125, respectively. Antioxidant N-acetylcysteine (NAC) was used as ROS scavenger. Field exposure induced transient activation of p38, JNK and ERK1/2. The MF proliferative effect, which was mediated by changes in the cell cycle, was blocked by the p38 inhibitor, but not by the JNK inhibitor. NAC blocked the field effects on cell proliferation and p38 activation, but not those on ERK1/2 activation. The MF-induced proliferative effects are exerted through sequential upregulation of MAPK-p38 and -ERK1/2 activation, and they are likely mediated by a ROS-dependent activation of p38. PMID:27058530

β-Adrenergic Receptor Stimulated Ncx1 Upregulation is Mediated via a CaMKII/AP-1 Signaling Pathway in Adult Cardiomyocytes

PubMed Central

Mani, Santhosh K.; Egan, Erin A.; Addy, Benjamin K.; Grimm, Michael; Kasiganesan, Harinath; Thiyagarajan, Thirumagal; Renaud, Ludivine; Brown, Joan Heller; Kern, Christine B.; Menick, Donald R.

2013-01-01

The Na+-Ca2+ exchanger gene (Ncx1) is upregulated in hypertrophy and is often found elevated in end-stage heart failure. Studies have shown that the change in its expression contributes to contractile dysfunction. β-adrenergic receptor (β-AR) signaling plays an important role in the regulation of calcium homeostasis in the cardiomyocyte but chronic activation in periods of cardiac stress contribute to heart failure by mechanisms which include Ncx1 upregulation. Here, using a Ca2+/Calmodulin-Dependent Protein Kinase II (CaMKIIδc) null mouse, we demonstrate that β-AR-stimulated Ncx1 upregulation is dependent on CaMKII. β-AR-stimulated Ncx1 expression is mediated by activator protein 1 (AP-1) factors and is independent of cAMP-response element-binding protein (CREB) activation. The MAP kinases (ERK1/2, JNK and p38) are not required for AP-1 factor activation. Chromatin immunoprecipitation demonstrates that β-AR stimulation activates the ordered recruitment of JunB homodimers which then are replaced by c-Jun homodimers binding to the proximal AP-1 elements of the endogenous Ncx1 promoter. In conclusion, this work has provided insight into the intracellular signaling pathways and transcription factors regulating Ncx1 gene expression in a chronically β-AR-stimulated heart. PMID:19945464

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

PubMed

Chen, Ying-Jung; Chang, Long-Sen

2015-10-01

The aim of this study is to explore the spatial association of critical genomic elements in the effect of TNF-α on matrix metalloproteinase-9 (MMP-9) expression in human leukemia U937 cells. TNF-α up-regulated MMP-9 protein expression and mRNA level in U937 cells, and Akt-mediated-NFκB/p65 activation and JNK-mediated c-Jun activation were proven to be involved in TNF-α-induced MMP-9 up-regulation. Promoter luciferase activity assay revealed that NFκB (nt-600) and AP-1 (nt-79) binding sites were crucial for TNF-α-induced transcription of MMP-9 gene. The results of a chromatin immunoprecipitation assay indicated that TNF-α reduced histone deacetylase-1 (HDAC-1) recruitment but increased p300 (a histone acetyltransferase) recruitment to MMP-9 promoter regions surrounding NFκB and AP-1 binding sites. Consistently, TNF-α increased enrichment of the acetylated histone H3 mark on MMP-9 promoter regions. DNA affinity purification assay revealed that p300 and HDAC1 could bind oligonucleotides containing AP-1/c-Jun and NFκB/p65 binding sites. Chromosome conformation capture assay showed that TNF-α stimulated chromosomal loops in the MMP-9 promoter via NFκB/p65 and AP-1/c-Jun. The p300-associated acetyltransferase activity was crucial for p65/c-Jun-mediated DNA looping, and inhibition of HDAC activity increased the level of DNA looping. Reduction in the level of DNA looping eliminated all TNF-α-stimulated MMP-9 up-regulation. Taken together, our data suggest that p65/c-Jun-mediated DNA looping is involved in TNF-α-induced MMP-9 up-regulation and that the recruitment of p300 or HDAC1 to NFκB and AP-1 binding sites modifies the level of DNA looping. Copyright © 2015 Elsevier B.V. All rights reserved.

Role of MAPK/MNK1 signaling in virus replication.

PubMed

Kumar, Ram; Khandelwal, Nitin; Thachamvally, Riyesh; Tripathi, Bhupendra Nath; Barua, Sanjay; Kashyap, Sudhir Kumar; Maherchandani, Sunil; Kumar, Naveen

2018-06-01

Viruses are obligate intracellular parasites; they heavily depend on the host cell machinery to effectively replicate and produce new progeny virus particles. Following viral infection, diverse cell signaling pathways are initiated by the cells, with the major goal of establishing an antiviral state. However, viruses have been shown to exploit cellular signaling pathways for their own effective replication. Genome-wide siRNA screens have also identified numerous host factors that either support (proviral) or inhibit (antiviral) virus replication. Some of the host factors might be dispensable for the host but may be critical for virus replication; therefore such cellular factors may serve as targets for development of antiviral therapeutics. Mitogen activated protein kinase (MAPK) is a major cell signaling pathway that is known to be activated by diverse group of viruses. MAPK interacting kinase 1 (MNK1) has been shown to regulate both cap-dependent and internal ribosomal entry sites (IRES)-mediated mRNA translation. In this review we have discuss the role of MAPK in virus replication, particularly the role of MNK1 in replication and translation of viral genome. Copyright © 2018 Elsevier B.V. All rights reserved.

Activating MAPK1 (ERK2) mutation in an aggressive case of disseminated juvenile xanthogranuloma

PubMed Central

Chakraborty, Rikhia; Hampton, Oliver A.; Abhyankar, Harshal; Zinn, Daniel J.; Grimes, Amanda; Skull, Brooks; Eckstein, Olive; Mahmood, Nadia; Wheeler, David A.; Lopez-Terrada, Dolores; Peters, Tricia L.; Hicks, John M.; Elghetany, Tarek; Krance, Robert; Poulikakos, Poulikos I.; Merad, Miriam; McClain, Kenneth L.; Allen, Carl E.; Parsons, Donald W.

2017-01-01

Juvenile xanthogranuloma (JXG) is a rare histiocytic disorder that is usually benign and self-limiting. We present a case of atypical, aggressive JXG harboring a novel mitogen-activated protein kinase (MAPK) pathway mutation in the MAPK1 gene, which encodes mitogen-activated protein kinase 1 or extracellular signal-regulated 2 (ERK2). Our analysis revealed that the mutation results in constitutive ERK activation that is resistant to BRAF or MEK inhibitors but susceptible to an ERK inhibitor. These data highlight the importance of identifying specific MAPK pathway alterations as part of the diagnostic workup for patients with histiocytic disorders rather than initiating empiric treatment with MEK inhibitors. PMID:28512266

Caffeine Inhibits the Activation of Hepatic Stellate Cells Induced by Acetaldehyde via Adenosine A2A Receptor Mediated by the cAMP/PKA/SRC/ERK1/2/P38 MAPK Signal Pathway

PubMed Central

Yang, Wanzhi; Wang, Qi; Zhao, Han; Yang, Feng; Lv, Xiongwen; Li, Jun

2014-01-01

Hepatic stellate cell (HSC) activation is an essential event during alcoholic liver fibrosis. Evidence suggests that adenosine aggravates liver fibrosis via the adenosine A2A receptor (A2AR). Caffeine, which is being widely consumed during daily life, inhibits the action of adenosine. In this study, we attempted to validate the hypothesis that caffeine influences acetaldehyde-induced HSC activation by acting on A2AR. Acetaldehyde at 50, 100, 200, and 400 μM significantly increased HSC-T6 cells proliferation, and cell proliferation reached a maximum at 48 h after exposure to 200 μM acetaldehyde. Caffeine and the A2AR antagonist ZM241385 decreased the cell viability and inhibited the expression of procollagen type I and type III in acetaldehyde-induced HSC-T6 cells. In addition, the inhibitory effect of caffeine on the expression of procollagen type I was regulated by A2AR-mediated signal pathway involving cAMP, PKA, SRC, and ERK1/2. Interestingly, caffeine’s inhibitory effect on the expression of procollagen type III may depend upon the A2AR-mediated P38 MAPK-dependent pathway. Conclusions: Caffeine significantly inhibited acetaldehyde-induced HSC-T6 cells activation by distinct A2AR mediated signal pathway via inhibition of cAMP-PKA-SRC-ERK1/2 for procollagen type I and via P38 MAPK for procollagen type III. PMID:24682220

Entire mitogen activated protein kinase (MAPK) pathway is present in preimplantation mouse embryos.

PubMed

Wang, Yingchun; Wang, Fangfei; Sun, Tong; Trostinskaia, Anna; Wygle, Dana; Puscheck, Elizabeth; Rappolee, Daniel A

2004-09-01

To understand how mitogenic signals are transduced into the trophoblasts in preimplantation embryos, the expression of mitogen-activated protein kinase (MAPK) pathway molecules was tested. We used immunocytochemical means and reverse transcriptase-polymerase chain reaction to test whether MAPK pathway molecule gene products exist at the protein and phosphoprotein level in the zygote and the RNA level in the egg and zygote. In addition, all antibodies detected the correct-sized major band in Westerns of placental cell lines representing the most prevalent cell type in preimplantation embryos. A majority of mRNA transcripts of MAPK pathway genes were detected in unfertilized eggs, and all were expressed in the zygote. We found that the MAPK pathway protein set consisting of the following gene products was present: FRS2 alpha, GRB2, GAB1, SOS1, Ha-ras, Raf1/RafB, MEK1,2,5, MAPK/ERK1,2, MAPK/ERK5, and RSK1,2,3 (see abbreviations). These proteins were detected in trophoblasts in embryonic day (E) 3.5 embryos when they could mediate mitogenic fibroblast growth factor signals from the embryo or colony stimulating factor-1 signals from the uterus. The phosphorylation state and position of the phosphoproteins in the cells suggested that they might function in mediating mitogenic signals. Interestingly, a subtle transition from maternal MAPK function to zygotic function was suggested by the localization for three MAPK pathway enzymes between E2.5 and E3.5, Raf1 phospho is largely cell membrane-localized at E2.5 and E3.5, and MEK1,2 phospho accumulates in the nucleus on E2.5 and E3.5. However, MAPK phospho shifts from nuclear accumulation at E2.5 to cytoplasmic accumulation at E3.5. This finding is similar to the cytoplasmic MAPK phospho localization reported in fibroblast growth factor signaling fields in postimplantation embryos (Corson et al. [2003] Development 130:4527-4537). This spatial and temporal expression study lays a foundation to plan and analyze perturbation

The dyad palindromic glutathione transferase P enhancer binds multiple factors including AP1.

PubMed Central

Diccianni, M B; Imagawa, M; Muramatsu, M

1992-01-01

Glutathione Transferase P (GST-P) gene expression is dominantly regulated by an upstream enhancer (GPEI) consisting of a dyad of palindromically oriented imperfect TPA (12-O-tetradecanoyl-phorbol-13-acetate)-responsive elements (TRE). GPEI is active in AP1-lacking F9 cells as well in AP1-containing HeLa cells. Despite GPEI's similarity to a TRE, c-jun co-transfection has only a minimal effect on transactivation. Antisense c-jun and c-fos co-transfection experiments further demonstrate the lack of a role for AP1 in GPEI mediated trans-activation in F9 cells, although endogenously present AP1 can influence GPEI in HeLa cells. Co-transfection of delta fosB with c-jun, which forms an inactive c-Jun/delta FosB heterodimer that binds TRE sequences, inhibits GPEI-mediated transcription in AP1-lacking F9 cells as well as AP1-containing HeLa cells. These data suggest novel factor(s) other than AP1 are influencing GPEI. Binding studies reveal multiple nucleoproteins bind to GPEI. These factors are likely responsible for the high level of GPEI-mediated transcription observed in the absence of AP1 and during hepatocarcinogenesis. Images PMID:1408831

The dyad palindromic glutathione transferase P enhancer binds multiple factors including AP1.

PubMed

Diccianni, M B; Imagawa, M; Muramatsu, M

1992-10-11

Glutathione Transferase P (GST-P) gene expression is dominantly regulated by an upstream enhancer (GPEI) consisting of a dyad of palindromically oriented imperfect TPA (12-O-tetradecanoyl-phorbol-13-acetate)-responsive elements (TRE). GPEI is active in AP1-lacking F9 cells as well in AP1-containing HeLa cells. Despite GPEI's similarity to a TRE, c-jun co-transfection has only a minimal effect on transactivation. Antisense c-jun and c-fos co-transfection experiments further demonstrate the lack of a role for AP1 in GPEI mediated trans-activation in F9 cells, although endogenously present AP1 can influence GPEI in HeLa cells. Co-transfection of delta fosB with c-jun, which forms an inactive c-Jun/delta FosB heterodimer that binds TRE sequences, inhibits GPEI-mediated transcription in AP1-lacking F9 cells as well as AP1-containing HeLa cells. These data suggest novel factor(s) other than AP1 are influencing GPEI. Binding studies reveal multiple nucleoproteins bind to GPEI. These factors are likely responsible for the high level of GPEI-mediated transcription observed in the absence of AP1 and during hepatocarcinogenesis.

Lapatinib increases motility of triple-negative breast cancer cells by decreasing miRNA-7 and inducing Raf-1/MAPK-dependent interleukin-6.

PubMed

Hsiao, Yu-Chun; Yeh, Ming-Hsin; Chen, Yun-Ju; Liu, Ju-Fang; Tang, Chih-Hsin; Huang, Wei-Chien

2015-11-10

Lapatinib, a dual epidermal growth factor receptor (EGFR) and HER2 tyrosine kinase inhibitor (TKI), has been approved for HER2-positive breast cancer patients. Nevertheless, its inhibitory effect on EGFR did not deliver clinical benefits for triple-negative breast cancer (TNBC) patients even EGFR overexpression was frequently found in this disease. Moreover, lapatinib was unexpectedly found to enhance metastasis of TNBC cells, but the underlying mechanisms are not fully understood. In this study, we explored that the level of interleukin-6 (IL-6) was elevated in lapatinib-treated TNBC cells. Treatment with IL-6 antibody abolished the lapatinib-induced migration. Mechanistically, the signaling axis of Raf-1/mitogen-activated protein kinases (MAPKs), c-Jun N-terminal kinases (JNKs), p38 MAPK, and activator protein 1 (AP-1) was activated in response to lapatinib treatment to induce IL-6 expression. Furthermore, our data showed that microRNA-7 directly binds and inhibits Raf-1 3'UTR activity, and that down-regulation of miR-7 by lapatinib contributes to the activation of Raf-1 signaling pathway and the induction of IL-6 expression. Our results not only revealed IL-6 as a key regulator of lapatinib-induced metastasis, but also explored the requirement of miR7/Raf-1/MAPK/AP-1 axis in lapatinib-induced IL-6 expression.

Lapatinib increases motility of triple-negative breast cancer cells by decreasing miRNA-7 and inducing Raf-1/MAPK-dependent interleukin-6

PubMed Central

Chen, Yun-Ju; Liu, Ju-Fang; Tang, Chih-Hsin; Huang, Wei-Chien

2015-01-01

Lapatinib, a dual epidermal growth factor receptor (EGFR) and HER2 tyrosine kinase inhibitor (TKI), has been approved for HER2-positive breast cancer patients. Nevertheless, its inhibitory effect on EGFR did not deliver clinical benefits for triple-negative breast cancer (TNBC) patients even EGFR overexpression was frequently found in this disease. Moreover, lapatinib was unexpectedly found to enhance metastasis of TNBC cells, but the underlying mechanisms are not fully understood. In this study, we explored that the level of interleukin-6 (IL-6) was elevated in lapatinib-treated TNBC cells. Treatment with IL-6 antibody abolished the lapatinib-induced migration. Mechanistically, the signaling axis of Raf-1/mitogen-activated protein kinases (MAPKs), c-Jun N-terminal kinases (JNKs), p38 MAPK, and activator protein 1 (AP-1) was activated in response to lapatinib treatment to induce IL-6 expression. Furthermore, our data showed that microRNA-7 directly binds and inhibits Raf-1 3′UTR activity, and that down-regulation of miR-7 by lapatinib contributes to the activation of Raf-1 signaling pathway and the induction of IL-6 expression. Our results not only revealed IL-6 as a key regulator of lapatinib-induced metastasis, but also explored the requirement of miR7/Raf-1/MAPK/AP-1 axis in lapatinib-induced IL-6 expression. PMID:26513016

Indoxyl sulfate enhances IL-1β-induced E-selectin expression in endothelial cells in acute kidney injury by the ROS/MAPKs/NFκB/AP-1 pathway.

PubMed

Shen, Wen-Ching; Liang, Chan-Jung; Huang, Tao-Ming; Liu, Chen-Wei; Wang, Shu-Huei; Young, Guang-Huar; Tsai, Jaw-Shiun; Tseng, Ying-Chin; Peng, Yu-Sen; Wu, Vin-Cent; Chen, Yuh-Lien

2016-11-01

Uremic toxins are considered a risk factor for cardiovascular disorders in kidney diseases, but it is not known whether, under inflammatory conditions, they affect adhesion molecule expression on endothelial cells, which may play a critical role in acute kidney injury (AKI). In the present study, in cardiovascular surgery-related AKI patients, who are known to have high plasma levels of the uremic toxin indoxyl sulfate (IS), plasma levels of IL-1β were found to be positively correlated with plasma levels of the adhesion molecule E-selectin. In addition, high E-selectin and IL-1β expression were seen in the kidney of ischemia/reperfusion mice in vivo. We also examined the effects of IS on E-selectin expression by IL-1β-treated human umbilical vein endothelial cells (HUVECs) and the underlying mechanism. IS pretreatment of HUVECs significantly increased IL-1β-induced E-selectin expression, monocyte adhesion, and the phosphorylation of mitogen-activated protein kinases (ERK, p38, and JNK) and transcription factors (NF-κB and AP-1), and phosphorylation was decreased by pretreatment with inhibitors of ERK1/2 (PD98059), p38 MAPK (SB202190), and JNK (SP600125). Furthermore, IS increased IL-1β-induced reactive oxygen species (ROS) production and this effect was inhibited by pretreatment with N-acetylcysteine (a ROS scavenger) or apocynin (a NADPH oxidase inhibitor). Gel shift assays and ChIP-PCR demonstrated that IS enhanced E-selectin expression in IL-1-treated HUVECs by increasing NF-κB and AP-1 DNA-binding activities. Moreover, IS-enhanced E-selectin expression in IL-1β-treated HUVECs was inhibited by Bay11-7082, a NF-κB inhibitor. Thus, IS may play an important role in the development of cardiovascular disorders in kidney diseases during inflammation by increasing endothelial expression of E-selectin.

Reactive oxygen species mediate nitric oxide production through ERK/JNK MAPK signaling in HAPI microglia after PFOS exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Cheng; Nie, Xiaoke; Zhang, Yan

2015-10-15

Perfluorooctane sulfonate (PFOS), an emerging persistent contaminant that is commonly encountered during daily life, has been shown to exert toxic effects on the central nervous system (CNS). However, the molecular mechanisms underlying the neurotoxicity of PFOS remain largely unknown. It has been widely acknowledged that the inflammatory mediators released by hyper-activated microglia play vital roles in the pathogenesis of various neurological diseases. In the present study, we examined the impact of PFOS exposure on microglial activation and the release of proinflammatory mediators, including nitric oxide (NO) and reactive oxidative species (ROS). We found that PFOS exposure led to concentration-dependent NOmore » and ROS production by rat HAPI microglia. We also discovered that there was rapid activation of the ERK/JNK MAPK signaling pathway in the HAPI microglia following PFOS treatment. Moreover, the PFOS-induced iNOS expression and NO production were attenuated after the inhibition of ERK or JNK MAPK by their corresponding inhibitors, PD98059 and SP600125. Interestingly, NAC, a ROS inhibitor, blocked iNOS expression, NO production, and activation of ERK and JNK MAPKs, which suggested that PFOS-mediated microglial NO production occurs via a ROS/ERK/JNK MAPK signaling pathway. Finally, by exposing SH-SY5Y cells to PFOS-treated microglia-conditioned medium, we demonstrated that NO was responsible for PFOS-mediated neuronal apoptosis. - Highlights: • PFOS exposure induced expression of iNOS and production of NO in HAPI microglia. • PFOS induced the production of ROS in HAPI microglia. • ERK/JNK MAPK pathways were activated following PFOS exposure in HAPI microglia. • NO released by HAPI microglia participated in the apoptosis of SH-SY5Y cells.« less

G Protein-regulated inducer of neurite outgrowth (GRIN) modulates Sprouty protein repression of mitogen-activated protein kinase (MAPK) activation by growth factor stimulation.

PubMed

Hwangpo, Tracy Anh; Jordan, J Dedrick; Premsrirut, Prem K; Jayamaran, Gomathi; Licht, Jonathan D; Iyengar, Ravi; Neves, Susana R

2012-04-20

Gα(o/i) interacts directly with GRIN (G protein-regulated inducer of neurite outgrowth). Using the yeast two-hybrid system, we identified Sprouty2 as an interacting partner of GRIN. Gα(o) and Sprouty2 bind to overlapping regions of GRIN, thus competing for GRIN binding. Imaging experiments demonstrated that Gα(o) expression promoted GRIN translocation to the plasma membrane, whereas Sprouty2 expression failed to do so. Given the role of Sprouty2 in the regulation of growth factor-mediated MAPK activation, we examined the contribution of the GRIN-Sprouty2 interaction to CB1 cannabinoid receptor regulation of FGF receptor signaling. In Neuro-2A cells, a system that expresses all of the components endogenously, modulation of GRIN levels led to regulation of MAPK activation. Overexpression of GRIN potentiated FGF activation of MAPK and decreased tyrosine phosphorylation of Sprouty2. Pretreatment with G(o/i)-coupled CB1 receptor agonist attenuated subsequent FGF activation of MAPK. Decreased expression of GRIN both diminished FGF activation of MAPK and blocked CB1R attenuation of MAPK activation. These observations indicate that Gα(o) interacts with GRIN and outcompetes GRIN from bound Sprouty. Free Sprouty then in turn inhibits growth factor signaling. Thus, here we present a novel mechanism of how G(o/i)-coupled receptors can inhibit growth factor signaling to MAPK.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Lian, E-mail: tounao@126.com; Institute of Immunology, School of Medicine, Shandong University, Jinan 250012; Zhang, Xin

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 whenmore » it fails to activate MAPK as expected.« less

Isoproterenol Acts as a Biased Agonist of the Alpha-1A-Adrenoceptor that Selectively Activates the MAPK/ERK Pathway

PubMed Central

Copik, Alicja. J.; Baldys, Aleksander; Nguyen, Khanh; Sahdeo, Sunil; Ho, Hoangdung; Kosaka, Alan; Dietrich, Paul J.; Fitch, Bill; Raymond, John R.; Ford, Anthony P. D. W.; Button, Donald; Milla, Marcos E.

2015-01-01

The α1A-AR is thought to couple predominantly to the Gαq/PLC pathway and lead to phosphoinositide hydrolysis and calcium mobilization, although certain agonists acting at this receptor have been reported to trigger activation of arachidonic acid formation and MAPK pathways. For several G protein-coupled receptors (GPCRs) agonists can manifest a bias for activation of particular effector signaling output, i.e. not all agonists of a given GPCR generate responses through utilization of the same signaling cascade(s). Previous work with Gαq coupling-defective variants of α1A-AR, as well as a combination of Ca2+ channel blockers, uncovered cross-talk between α1A-AR and β2-AR that leads to potentiation of a Gαq-independent signaling cascade in response to α1A-AR activation. We hypothesized that molecules exist that act as biased agonists to selectively activate this pathway. In this report, isoproterenol (Iso), typically viewed as β-AR-selective agonist, was examined with respect to activation of α1A-AR. α1A-AR selective antagonists were used to specifically block Iso evoked signaling in different cellular backgrounds and confirm its action at α1A-AR. Iso induced signaling at α1A-AR was further interrogated by probing steps along the Gαq /PLC, Gαs and MAPK/ERK pathways. In HEK-293/EBNA cells transiently transduced with α1A-AR, and CHO_α1A-AR stable cells, Iso evoked low potency ERK activity as well as Ca2+ mobilization that could be blocked by α1A-AR selective antagonists. The kinetics of Iso induced Ca2+ transients differed from typical Gαq- mediated Ca2+ mobilization, lacking both the fast IP3R mediated response and the sustained phase of Ca2+ re-entry. Moreover, no inositol phosphate (IP) accumulation could be detected in either cell line after stimulation with Iso, but activation was accompanied by receptor internalization. Data are presented that indicate that Iso represents a novel type of α1A-AR partial agonist with signaling bias toward MAPK

Roles for the Mitogen-activated Protein Kinase (MAPK) Phosphatase, DUSP1, in Feedback Control of Inflammatory Gene Expression and Repression by Dexamethasone*

PubMed Central

Shah, Suharsh; King, Elizabeth M.; Chandrasekhar, Ambika; Newton, Robert

2014-01-01

Glucocorticoids act on the glucocorticoid receptor (NR3C1) to repress inflammatory gene expression. This is central to their anti-inflammatory effectiveness and rational improvements in therapeutic index depend on understanding the mechanism. Human pulmonary epithelial A549 cells were used to study the role of the mitogen-activated protein kinase (MAPK) phosphatase, dual-specificity phosphatase 1 (DUSP1), in the dexamethasone repression of 11 inflammatory genes induced, in a MAPK-dependent manner, by interleukin-1β (IL1B). Adenoviral over-expression of DUSP1 inactivated MAPK pathways and reduced expression of all 11 inflammatory genes. IL1B rapidly induced DUSP1 expression and RNA silencing revealed a transient role in feedback inhibition of MAPKs and inflammatory gene expression. With dexamethasone, which induced DUSP1 expression, plus IL1B (co-treatment), DUSP1 expression was further enhanced. At 1 h, this was responsible for the dexamethasone inhibition of IL1B-induced MAPK activation and CXCL1 and CXCL2 mRNA expression, with a similar trend for CSF2. Whereas, CCL20 mRNA was not repressed by dexamethasone at 1 h, repression of CCL2, CXCL3, IL6, and IL8 was unaffected, and PTGS2 repression was partially affected by DUSP1 knockdown. At later times, dexamethasone repression of MAPKs was unaffected by DUSP1 silencing. Likewise, 6 h post-IL1B, dexamethasone repression of all 11 mRNAs was essentially unaffected by DUSP1 knockdown. Qualitatively similar data were obtained for CSF2, CXCL1, IL6, and IL8 release. Thus, despite general roles in feedback inhibition, DUSP1 plays a transient, often partial, role in the dexamethasone-dependent repression of certain inflammatory genes. Therefore this also illustrates key roles for DUSP1-independent effectors in mediating glucocorticoid-dependent repression. PMID:24692548

Role of ubiquitin and the HPV E6 oncoprotein in E6AP-mediated ubiquitination

PubMed Central

Mortensen, Franziska; Schneider, Daniel; Barbic, Tanja; Sladewska-Marquardt, Anna; Kühnle, Simone; Marx, Andreas; Scheffner, Martin

2015-01-01

Deregulation of the ubiquitin ligase E6 associated protein (E6AP) encoded by the UBE3A gene has been associated with three different clinical pictures. Hijacking of E6AP by the E6 oncoprotein of distinct human papillomaviruses (HPV) contributes to the development of cervical cancer, whereas loss of E6AP expression or function is the cause of Angelman syndrome, a neurodevelopmental disorder, and increased expression of E6AP has been involved in autism spectrum disorders. Although these observations indicate that the activity of E6AP has to be tightly controlled, only little is known about how E6AP is regulated at the posttranslational level. Here, we provide evidence that the hydrophobic patch of ubiquitin comprising Leu-8 and Ile-44 is important for E6AP-mediated ubiquitination, whereas it does not affect the catalytic properties of the isolated catalytic HECT domain of E6AP. Furthermore, we show that the HPV E6 oncoprotein rescues the disability of full-length E6AP to use a respective hydrophobic patch mutant of ubiquitin for ubiquitination and that it stimulates E6AP-mediated ubiquitination of Ring1B, a known substrate of E6AP, in vitro and in cells. Based on these data, we propose that E6AP exists in at least two different states, an active and a less active or latent one, and that the activity of E6AP is controlled by noncovalent interactions with ubiquitin and allosteric activators such as the HPV E6 oncoprotein. PMID:26216987

c-Jun/AP-1 pathway-mediated cyclin D1 expression participates in low dose arsenite-induced transformation in mouse epidermal JB6 Cl41 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Dongyun; Li Jingxia; Gao Jimin

2009-02-15

Arsenic is a well-documented human carcinogen associated with skin carcinogenesis. Our previous work reveals that arsenite exposure is able to induce cell transformation in mouse epidermal cell JB6 Cl41 through the activation of ERK, rather than JNK pathway. Our current studies further evaluate downstream pathway in low dose arsenite-induced cell transformation in JB6 Cl41 cells. Our results showed that treatment of cells with low dose arsenite induced activation of c-Jun/AP-1 pathway, and ectopic expression of dominant negative mutant of c-Jun (TAM67) blocked arsenite-induced transformation. Furthermore, our data indicated that cyclin D1 was an important downstream molecule involved in c-Jun/AP-1-mediated cellmore » transformation upon low dose arsenite exposure, because inhibition of cyclin D1 expression by its specific siRNA in the JB6 Cl41 cells resulted in impairment of anchorage-independent growth of cells induced by low dose arsenite. Collectively, our results demonstrate that c-Jun/AP-1-mediated cyclin D1 expression is at least one of the key events implicated in cell transformation upon low dose arsenite exposure.« less

p38 MAPK-Mediated Bmi-1 Down-Regulation and Defective Proliferation in ATM-Deficient Neural Stem Cells Can Be Restored by Akt Activation

PubMed Central

Kim, Jeesun; Hwangbo, Jeon; Wong, Paul K. Y.

2011-01-01

A-T (ataxia telangiectasia) is a genetic disease caused by a mutation in the Atm (A-T mutated) gene that leads to neurodegeneration. Despite an increase in the numbers of studies in this area in recent years, the mechanisms underlying neurodegeneration in human A-T are still poorly understood. Previous studies demonstrated that neural stem cells (NSCs) isolated from the subventricular zone (SVZ) of Atm -/- mouse brains show defective self-renewal and proliferation, which is accompanied by activation of chronic p38 mitogen-activated protein kinase (MAPK) and a lower level of the polycomb protein Bmi-1. However, the mechanism underlying Bmi-1 down-regulation and its relevance to defective proliferation in Atm-/- NSCs remained unclear. Here, we show that over-expression of Bmi-1 increases self-renewal and proliferation of Atm-/- NSCs to normal, indicating that defective proliferation in Atm-/- NSCs is a consequence of down-regulation of Bmi-1. We also demonstrate that epidermal growth factor (EGF)-induced Akt phosphorylation renders Bmi-1 resistant to the proteasomal degradation, leading to its stabilization and accumulation in the nucleus. However, inhibition of the Akt-dependent Bmi-1 stabilizing process by p38 MAPK signaling reduces the levels of Bmi-1. Treatment of the Atm-/- NSCs with a specific p38 MAPK inhibitor SB203580 extended Bmi-1 posttranscriptional turnover and H2A ubiquitination in Atm-/- NSCs. Our observations demonstrate the molecular basis underlying the impairment of self-renewal and proliferation in Atm-/- NSCs through the p38 MAPK-Akt-Bmi-1-p21 signaling pathway. PMID:21305053

MCP-1-mediated activation of microglia promotes white matter lesions and cognitive deficits by chronic cerebral hypoperfusion in mice.

PubMed

Yuan, Bangqing; Shi, Hui; Zheng, Kuang; Su, Zulu; Su, Hai; Zhong, Ming; He, Xuenong; Zhou, Changlong; Chen, Hao; Xiong, Qijiang; Zhang, Yi; Yang, Zhao

2017-01-01

Microglia activation played a vital role in the pathogenesis of white matter lesions (WMLs) by chronic cerebral hypoperfusion. In addition, hypoxia induced up-regulated expression of MCP-1, promotes the activation of microglia. However, the role of MCP-1-mediated microglia activation in chronic cerebral ischemia is still unknown. To explore that, chronic cerebral hypoperfusion model was established by permanent stenosis of bilateral common carotid artery in mice. The activation of microglia and the related signal pathway p38MAPK/PKC in white matter, and working memory of mice were observed. We found that stenosis of common carotid arteries could induce MCP-1-mediated activation of microglia through p38MAPK/PKC pathway and white matter lesions. Taken together, our findings represent a novel mechanism of MCP-1 involved in activation of microglia and provide a novel therapeutical strategy for chronic cerebral hypoperfusion. Copyright © 2016 Elsevier Inc. All rights reserved.

Anti-Inflammatory Effect of Apigenin on LPS-Induced Pro-Inflammatory Mediators and AP-1 Factors in Human Lung Epithelial Cells.

PubMed

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

2016-02-01

Apigenin is one of the plant flavonoids present in fruits and vegetables, acting as an important nutraceutical component. It is recognized as a potential antioxidant, antimicrobial, and anti-inflammatory molecule. In the present study, the mechanism of anti-inflammatory action of apigenin on lipopolysaccharide (LPS)-induced pro-inflammatory cytokines and activator protein-1 (AP-1) factors in human lung A549 cells was investigated. The anti-inflammatory activity of apigenin on LPS-induced inflammation was determined by analyzing the expression of pro-inflammatory cytokines, nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and different AP-1 factors. Apigenin significantly inhibited the LPS-induced expression of iNOS, COX-2, expression of pro-inflammatory cytokines (IL-1β, IL-2, IL-6, IL-8, and TNF-α), and AP-1 proteins (c-Jun, c-Fos, and JunB) including nitric oxide production. Study confirms the anti-inflammatory effect of apigenin by inhibiting the expression of inflammatory mediators and AP-1 factors involved in the inflammation and its importance in the treatment of lung inflammatory diseases.

L-Ascorbate Attenuates the Endotoxin-Induced Production of Inflammatory Mediators by Inhibiting MAPK Activation and NF-κB Translocation in Cortical Neurons/Glia Cocultures

PubMed Central

Huang, Ya-Ni; Lai, Chien-Cheng; Chiu, Chien-Tsai; Lin, Jhen-Jhe; Wang, Jia-Yi

2014-01-01

In response to acute insults to the central nervous system, such as pathogen invasion or neuronal injuries, glial cells become activated and secrete inflammatory mediators such as nitric oxide (NO), cytokines, and chemokines. This neuroinflammation plays a crucial role in the pathophysiology of chronic neurodegenerative diseases. Endogenous ascorbate levels are significantly decreased among patients with septic encephalopathy. Using the bacterial endotoxin lipopolysaccharide (LPS) to induce neuroinflammation in primary neuron/glia cocultures, we investigated how L-ascorbate (vitamin C; Vit. C) affected neuroinflammation. LPS (100 ng/ml) induced the expression of inducible NO synthase (iNOS) and the production of NO, interleukin (IL)-6, and macrophage inflammatory protein-2 (MIP-2/CXCL2) in a time-dependent manner; however, cotreatment with Vit. C (5 or 10 mM) attenuated the LPS-induced iNOS expression and production of NO, IL-6, and MIP-2 production. The morphological features revealed after immunocytochemical staining confirmed that Vit. C suppressed LPS-induced astrocytic and microglial activation. Because Vit. C can be transported into neurons and glia via the sodium-dependent Vit. C transporter-2, we examined how Vit. C affected LPS-activated intracellular signaling in neuron/glia cocultures. The results indicated the increased activation (caused by phosphorylation) of mitogen-activated protein kinases (MAPKs), such as p38 at 30 min and extracellular signal-regulated kinases (ERKs) at 180 min after LPS treatment. The inhibition of p38 and ERK MAPK suppressed the LPS-induced production of inflammatory mediators. Vit. C also inhibited the LPS-induced activation of p38 and ERK. Combined treatments of Vit. C and the inhibitors of p38 and ERK yielded no additional inhibition compared with using the inhibitors alone, suggesting that Vit. C functions through the same signaling pathway (i.e., MAPK) as these inhibitors. Vit. C also reduced LPS-induced Iκ

Leptin regulates MMP-2, TIMP-1 and collagen synthesis via p38 MAPK in HL-1 murine cardiomyocytes.

PubMed

Schram, Kristin; De Girolamo, Sabrina; Madani, Siham; Munoz, Diana; Thong, Farah; Sweeney, Gary

2010-12-01

A clear association between obesity and heart failure exists and a significant role for leptin, the product of the obese gene, has been suggested. One aspect of myocardial remodeling which characterizes heart failure is a disruption in the balance of extracellular matrix synthesis and degradation. Here we investigated the effects of leptin on matrix metalloproteinase (MMP) activity, tissue inhibitor of metalloproteinase (TIMP) expression, as well as collagen synthesis in HL-1 cardiac muscle cells. Gelatin zymographic analysis of MMP activity in conditioned media showed that leptin enhanced MMP-2 activity in a dose- and time-dependent manner. Leptin is known to stimulate phosphorylation of p38 MAPK in cardiac cells and utilization of the p38 MAPK inhibitor, SB203580, demonstrated that this kinase also plays a role in regulating several extracellular matrix components, such that inhibition of p38 MAPK signaling prevented the leptin-induced increase in MMP-2 activation. We also observed that leptin enhanced collagen synthesis determined by both proline incorporation and picrosirius red staining of conditioned media. Pro-collagen type-I and pro-collagen type-III expression, measured by real-time PCR and Western blotting were also increased by leptin, effects which were again attenuated by SB203580. In summary, these results demonstrate the potential for leptin to play a role in mediating myocardial ECM remodeling and that the p38 MAPK pathway plays an important role in mediating these effects.

Dihydroavenanthramide D inhibits human breast cancer cell invasion through suppression of MMP-9 expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Young-Rae; Noh, Eun-Mi; Oh, Hyun Ju

2011-02-25

Research highlights: {yields} MMP-9 plays a pivotal role in the invasion of MCF-7 breast cancer cells. {yields} TPA stimulates MMP-9 expression through activation of MAPK/NF-{kappa}B and MAPK/AP-1 pathways. {yields} Dihydroavenanthramide D suppresses MMP-9 expression via inhibition of TPA-induced MAPK/NF-{kappa}B and MAPK/AP-1 activations. {yields} Dihydroavenanthramide D blocks cell invasion of MCF-7 breast cancer cells. -- Abstract: Dihydroavenanthramide D (DHAvD) is a synthetic analog to naturally occurring avenanthramide, which is the active component of oat. Previous study demonstrates that DHAvD strongly inhibits activation of nuclear factor-kappa B (NF-{kappa}B), which is a major component in cancer cell invasion. The present study investigated whethermore » DHAvD can modulate MMP-9 expression and cell invasion in MCF-7 human breast cancer cells. MMP-9 expression and cell invasion in response to 12-O-tetradecanoylphorbol-13-acetate (TPA) was increased, whereas these inductions were muted by DHAvD. DHAvD also suppressed activation of mitogen-activated protein kinase (MAPK), and MAPK-mediated nuclear factor-kappa B (NF-{kappa}B) and activator protein-1 (AP-1) activations in TPA-treated MCF-7 cells. The results indicate that DHAvD-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of the MAPK/NF-{kappa}B and MAPK/AP-1 pathways in MCF-7 cells. DHAvD may have potential value in breast cancer metastasis.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeon, Youngsic; Jung, Yujung; Kim, Min Cheol

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-agingmore » 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.« less

Gypenoside IX Suppresses p38 MAPK/Akt/NFκB Signaling Pathway Activation and Inflammatory Responses in Astrocytes Stimulated by Proinflammatory Mediators.

PubMed

Wang, Xiaoshuang; Yang, Liu; Yang, Li; Xing, Faping; Yang, Hua; Qin, Liyue; Lan, Yunyi; Wu, Hui; Zhang, Beibei; Shi, Hailian; Lu, Cheng; Huang, Fei; Wu, Xiaojun; Wang, Zhengtao

2017-12-01

Gypenoside IX (GP IX) is a pure compound isolated from Panax notoginseng. Gypenosides have been implicated to benefit the recovery of enormous neurological disorders. By suppressing the activation of astrocytes, gypenosides can improve the cognitive impairment. However, so far, little is known about whether GP IX could restrain the inflammatory responses in astrocytes or reactive astrogliosis. In present study, the anti-inflammatory effects of GP IX were investigated in reactive astrocytes induced by proinflammatory mediators both in vitro and in vivo. GP IX significantly reduced the production of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) at either protein or mRNA level in glial cell line C6 cells stimulated by lipopolysaccharide (LPS)/TNF-α combination. It also alleviated the astrogliosis and decreased the production of inflammatory mediators in brain cortex of LPS-treated mice. Further study disclosed that GP IX inhibited nuclear translocation of nuclear factor kappa B (NFκB) and reduced its transcriptional activity. Meanwhile, GP IX significantly attenuated the phosphorylation of NFκB, inhibitor of kappa B (IκB), Akt, and p38 mitogen-activated protein kinase (MAPK) under inflammatory conditions both in vitro and in vivo. These findings indicated that GP IX might suppress reactive astrogliosis by suppressing Akt/p38 MAPK/NFκB signaling pathways. And GP IX might be a promising drug candidate or prodrug for the therapy of neuroinflammatory disorders characterized with reactive astrogliosis.

Interleukin‑1β‑mediated suppression of microRNA‑27a‑3p activity in human cartilage via MAPK and NF‑κB pathways: A potential mechanism of osteoarthritis pathogenesis.

PubMed

Li, Xing; He, Peiheng; Li, Ziqing; Wang, Haixing; Liu, Minghao; Xiao, Yinbo; Xu, Dongliang; Kang, Yan; Wang, Hua

2018-05-04

The aim of the present study was to investigate the role of microRNA (miR)‑27a‑3p in osteoarthritis (OA). Reverse transcription‑quantitative polymerase chain reaction and western blotting were performed to determine the expression of miR‑27a‑3p and aggrecanase‑2 (ADAMTS5) in cartilage tissues from patients with OA and healthy controls, and also in interleukin (IL)‑1β‑treated primary human chondrocytes. Primary human chondrocytes were transfected with miR‑27a‑3p. A luciferase reporter assay was used to validate the direct contact between miR‑27a‑3p and its putative binding site in the 3'‑untranslated region ADAMTS5 mRNA. Furthermore, the effects of IL‑1β‑induced activation of mitogen‑activated protein kinase (MAPK) and nuclear factor (NF)‑κB on miR‑27a‑3p were evaluated using specific inhibitors. The results revealed that the level of miR‑27a‑3p was reduced in OA cartilage tissues compared with those of normal controls. In addition, decreased miR‑27a‑3p and increased ADAMTS5 expression was observed in a time‑ and dose‑dependent manner in chondrocytes treated with IL‑1β. Furthermore, overexpression of miR‑27a‑3p suppressed the expression of ADAMTS5 in human chondrocytes induced by IL‑1β. miR‑27a‑3p overexpression also decreased the luciferase activity of the wild‑type ADAMTS5 reporter plasmid. Mutation of the miR‑27a‑3p binding site in the 3'‑untranslated region of ADAMTS5 mRNA abolished the miR‑27a‑3p‑mediated repression of reporter activity. Furthermore, the use of specific inhibitors demonstrated that IL‑1β may regulate miR‑27a‑3p expression via NF‑κB and MAPK signaling pathways in chondrocytes. The present study concluded that miR‑27a‑3p was downregulated in human OA and was suppressed by IL‑1β, and functions as a crucial regulator of ADAMTS5 in OA chondrocytes. In addition, IL‑1β‑mediated suppression of miR‑27a‑3p activity may occur via the MAPK and NF�

CD28 co-stimulation restores T cell responsiveness in NOD mice by overcoming deficiencies in Rac-1/p38 mitogen-activated protein kinase signaling and IL-2 and IL-4 gene transcription.

PubMed

Zhang, J; Salojin, K V; Delovitch, T L

2001-03-01

Previously, we reported that T cell hyporesponsiveness induced by TCR ligation is causal to autoimmune diabetes in NOD mice. Neonatal CD28 co-stimulation reverses T cell hyporesponsiveness and protects NOD mice from diabetes by an IL-4-mediated mechanism, indicating that a deficiency in TCR signaling may be overcome by CD28/B7-2 co-stimulation in NOD T cells. To investigate which co-stimulation-induced signaling events mediate this protection, we analyzed the activity of Ras, Rac-1, mitogen-activated protein kinases (MAPK) and several transcription factors in TCR-activated NOD T cells in the presence or absence of CD28 co-stimulation. We show that CD28 co-stimulation restores normal TCR-induced activation of Rac-1 and p38 MAPK in NOD T cells. Deficiencies in TCR-induced nuclear expression of activating protein (AP)-1 binding proteins as well as activation of AP-1 and NF-AT in the IL-2 and IL-4 P1 promoters are also corrected by CD28 co-stimulation. Thus, CD28 co-stimulation reverses NOD T cell hyporesponsiveness by restoring TCR signaling leading to the activation of AP-1 and NF-AT during IL-2 and IL-4 gene transcription. Our findings provide additional evidence that CD28 co-stimulation amplifies signals delivered by the TCR and further explain the mechanism by which CD28 co-stimulation may protect against autoimmune diabetes.

Fisetin Protects PC12 Cells from Tunicamycin-Mediated Cell Death via Reactive Oxygen Species Scavenging and Modulation of Nrf2-Driven Gene Expression, SIRT1 and MAPK Signaling in PC12 Cells.

PubMed

Yen, Jui-Hung; Wu, Pei-Shan; Chen, Shu-Fen; Wu, Ming-Jiuan

2017-04-17

Fisetin (3,7,3',4'-tetrahydroxyflavone) is a dietary flavonol and exhibits antioxidant, anti-inflammatory, and neuroprotective activities. However, high concentration of fisetin is reported to produce reactive oxygen species (ROS), induce endoplasmic reticulum (ER) stress and cause cytotoxicity in cancer cells. The aim of this study is to investigate the cytoprotective effects of low concentration of fisetin against tunicamycin (Tm)-mediated cytotoxicity in neuronal-like catecholaminergic PC12 cells. Cell viability was assayed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and apoptotic and autophagic markers were analyzed by Western blot. Gene expression of unfolded protein response (UPR) and Phase II enzymes was further investigated using RT-Q-PCR or Western blotting. Intracellular ROS level was measured using 2',7'-dichlorodihydrofluorescein diacetate (H₂DCFDA) by a fluorometer. The effects of fisetin on mitogen activated protein kinases (MAPKs) and SIRT1 (Sirtuin 1) signaling pathways were examined using Western blotting and specific inhibitors. Fisetin (<20 µM) restored cell viability and repressed apoptosis, autophagy and ROS production in Tm-treated cells. Fisetin attenuated Tm-mediated expression of ER stress genes, such as glucose-regulated proteins 78 (GRP78), C/EBP homologous protein (CHOP also known as GADD153) and Tribbles homolog 3 (TRB3), but induced the expression of nuclear E2 related factor (Nrf)2-targeted heme oxygenase (HO)-1, glutamate cysteine ligase (GCL) and cystine/glutamate transporter (xCT/SLC7A11), in both the presence and absence of Tm. Moreover, fisetin enhanced phosphorylation of ERK (extracellular signal-regulated kinase), JNK (c-JUN NH₂-terminal protein kinase), and p38 MAPK. Addition of JNK and p38 MAPK inhibitor significantly antagonized its cytoprotective activity and modulatory effects on UPR. Fisetin also restored Tm-inhibited SIRT1 expression and addition of sirtinol (SIRT1 activation inhibitor

Gallic Acid Inhibited Matrix Invasion and AP-1/ETS-1-Mediated MMP-1 Transcription in Human Nasopharyngeal Carcinoma Cells

PubMed Central

S. Pang, Jong-Hwei; Yen, Jia-Hau; Wu, Hsiao-Ting; Huang, Sheng-Teng

2017-01-01

Gallic acid is a trihydroxybenzoic acid found in natural herbal plants. Gallic acid has been reported to inhibit the migration and invasive capability of various cancers. Little is known about the underlying mechanisms of invasion responsible for cancer metastasis via gallic acid. The present study was intended to investigate the anti-invasive effect of gallic acid on human nasopharyngeal carcinoma cells (NPC-BM1) and its related mechanism. Gallic acid inhibited the invasion of NPC-BM1 cells dose- and time-dependently without significant cytotoxic effect. Affymetrix oligonucleotide microarray analysis revealed matrix metalloproteinase-1 (MMP-1) as the most down-regulated gene in NPC-BM1 cells by gallic acid. The cytosolic and secreted MMP-1 levels were both found to be inhibited by gallic acid as demonstrated by western blot analysis and ELISA respectively. The mRNA expression and transcription of MMP-1 gene was also down-regulated as determined by RT/real-time PCR and promoter activity assay. The expression of two major transcription binding factors in the MMP-1 promoter, AP-1 and ETS-1, were demonstrated to be reduced by gallic acid in NPC-BM1 cells. The effect of gallic acid was associated with the inhibition of p38 MAPK signaling pathway. In addition, gallic acid enhanced the gene expression of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) which further suppressed the MMP-1 activity. These findings may be useful to develop a novel chemotherapeutic agent to inhibit the metastasis of nasopharyngeal cancer. PMID:28672814

Gallic Acid Inhibited Matrix Invasion and AP-1/ETS-1-Mediated MMP-1 Transcription in Human Nasopharyngeal Carcinoma Cells.

PubMed

Pang, Jong-Hwei S; Yen, Jia-Hau; Wu, Hsiao-Ting; Huang, Sheng-Teng

2017-06-24

Gallic acid is a trihydroxybenzoic acid found in natural herbal plants. Gallic acid has been reported to inhibit the migration and invasive capability of various cancers. Little is known about the underlying mechanisms of invasion responsible for cancer metastasis via gallic acid. The present study was intended to investigate the anti-invasive effect of gallic acid on human nasopharyngeal carcinoma cells (NPC-BM1) and its related mechanism. Gallic acid inhibited the invasion of NPC-BM1 cells dose- and time-dependently without significant cytotoxic effect. Affymetrix oligonucleotide microarray analysis revealed matrix metalloproteinase-1 (MMP-1) as the most down-regulated gene in NPC-BM1 cells by gallic acid. The cytosolic and secreted MMP-1 levels were both found to be inhibited by gallic acid as demonstrated by western blot analysis and ELISA respectively. The mRNA expression and transcription of MMP-1 gene was also down-regulated as determined by RT/real-time PCR and promoter activity assay. The expression of two major transcription binding factors in the MMP-1 promoter, AP-1 and ETS-1, were demonstrated to be reduced by gallic acid in NPC-BM1 cells. The effect of gallic acid was associated with the inhibition of p38 MAPK signaling pathway. In addition, gallic acid enhanced the gene expression of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) which further suppressed the MMP-1 activity. These findings may be useful to develop a novel chemotherapeutic agent to inhibit the metastasis of nasopharyngeal cancer.

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

Brominated flame retardants, tetrabromobisphenol A and hexabromocyclododecane, activate mitogen-activated protein kinases (MAPKs) in human natural killer cells.

PubMed

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

2014-12-01

Natural killer (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.

1,25-Dihydroxyvitamin D3 attenuates endotoxin-induced production of inflammatory mediators by inhibiting MAPK activation in primary cortical neuron-glia cultures.

PubMed

Huang, Ya-Ni; Ho, Yi-Jung; Lai, Chien-Cheng; Chiu, Chien-Tsai; Wang, Jia-Yi

2015-08-12

Neuroinflammation occurs in insulted regions of the brain and may be due to reactive oxygen species (ROS), nitric oxide (NO), cytokines, and chemokines produced by activated glia. Excessive production of neurotoxic molecules causes further neuronal damage. Low levels of vitamin D3 are a risk factor for various brain diseases. Using the bacterial endotoxin, lipopolysaccharide (LPS), to induce neuroinflammation in primary cortical neuron-glia cultures, we investigated how 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) affected neuroinflammation. LPS (100 ng/ml) induced the accumulation of nitrite and the production of ROS, interleukin (IL)-6, and macrophage inflammatory protein (MIP)-2 in time-dependent manners. Inhibition of p38 and extracellular signal-regulated kinase (ERK) but not c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) by 20 μM of SB203580, PD98059, and SP600125, significantly reduced LPS-induced ROS production, NO accumulation, and inducible NO synthase (iNOS) expression, respectively. LPS-induced IL-6 and MIP-2 were significantly attenuated by inhibition of p38, ERK, and JNK MAPK. Cotreatment with 1,25(OH)2D3 attenuated LPS-induced ROS production, NO accumulation, and iNOS expression in concentration-dependent manners. 1,25(OH)2D3 also reduced LPS-induced production of IL-6 and MIP-2. Similarly, iNOS, IL-6, and MIP-2 mRNA expression in cells treated with LPS significantly increased, whereas this effect was attenuated by 1,25(OH)2D3. Moreover, LPS-induced phosphorylation of p38, ERK, and JNK MAPK was significantly inhibited by 1,25(OH)2D3. Our findings indicate that 1,25(OH)2D3 reduced the LPS-stimulated production of inflammatory molecules in neuron-glia cultures by inhibiting MAPK pathways and the production of downstream inflammatory molecules. We suggest that 1,25(OH)2D3 can be used to alleviate neuroinflammation in various brain injuries.

Implication of the ERK/MAPK pathway in antipsychotics-induced dopamine D2 receptor upregulation and in the preventive effects of (±)-α-lipoic acid in SH-SY5Y neuroblastoma cells.

PubMed

Deslauriers, Jessica; Desmarais, Christian; Sarret, Philippe; Grignon, Sylvain

2014-03-01

Chronic administration of antipsychotics (APs) has been associated with dopamine D2 receptor (D2R) upregulation and tardive dyskinesia. We previously showed that haloperidol, a first-generation AP, exerted a more robust increase in D2R expression than amisulpride, a second-generation AP and that (±)-α-lipoic acid pre-treatment reversed the AP-induced D2R upregulation. We also demonstrated that the Akt/GSK-3β/β-catenin pathway is involved in the control of D2R expression levels, but is unlikely implicated in the preventive effects of (±)-α-lipoic acid since co-treatment with haloperidol and (±)-α-lipoic acid exerts synergistic effects on Akt/GSK-3β activation. These findings led us to examine whether the ERK/MAPK signaling pathway may be involved in D2R upregulation elicited by APs, and in its reversal by (±)-α-lipoic acid, in SH-SY5Y human neuroblastoma cells. Our results revealed that haloperidol, in parallel with an elevation in D2R mRNA levels, induced a larger increase of ERK (p42/p44) phosphorylation than amisulpride. Pre-treatment with the selective ERK inhibitor U0126 attenuated haloperidol-induced increase in D2R upregulation. Furthermore, (±)-α-lipoic acid prevented AP-induced ERK activation. These results show that (1) the ERK/MAPK pathway is involved in haloperidol-induced D2R upregulation; (2) the preventive effect of (±)-α-lipoic acid on haloperidol-induced D2R upregulation is in part mediated by an ERK/MAPK-dependent signaling cascade. Taken together, our data suggest that (±)-α-lipoic acid exerts synergistic effects with haloperidol on the Akt/GSK-3β pathway, potentially involved in the therapeutic effects of APs, and antagonism of ERK activation and D2R upregulation, potentially involved in tardive dyskinesia and treatment resistance.

Luteolin and Apigenin Attenuate 4-Hydroxy-2-Nonenal-Mediated Cell Death through Modulation of UPR, Nrf2-ARE and MAPK Pathways in PC12 Cells

PubMed Central

Wu, Pei-Shan; Yen, Jui-Hung; Kou, Mei-Chun; Wu, Ming-Jiuan

2015-01-01

Luteolin and apigenin are dietary flavones and exhibit a broad spectrum of biological activities including antioxidant, anti-inflammatory, anti-cancer and neuroprotective effects. The lipid peroxidation product 4-hydroxy-2-nonenal (4-HNE) has been implicated as a causative agent in the development of neurodegenerative disorders. This study investigates the cytoprotective effects of luteolin and apigenin against 4-HNE-mediated cytotoxicity in neuronal-like catecholaminergic PC12 cells. Both flavones restored cell viability and repressed caspase-3 and PARP-1 activation in 4-HNE-treated cells. Luteolin also mitigated 4-HNE-mediated LC3 conversion and reactive oxygen species (ROS) production. Luteolin and apigenin up-regulated 4-HNE-mediated unfolded protein response (UPR), leading to an increase in endoplasmic reticulum chaperone GRP78 and decrease in the expression of UPR-targeted pro-apoptotic genes. They also induced the expression of Nrf2-targeted HO-1 and xCT in the absence of 4-HNE, but counteracted their expression in the presence of 4-HNE. Moreover, we found that JNK and p38 MAPK inhibitors significantly antagonized the increase in cell viability induced by luteolin and apigenin. Consistently, enhanced phosphorylation of JNK and p38 MAPK was observed in luteolin- and apigenin-treated cells. In conclusion, this result shows that luteolin and apigenin activate MAPK and Nrf2 signaling, which elicit adaptive cellular stress response pathways, restore 4-HNE-induced ER homeostasis and inhibit cytotoxicity. Luteolin exerts a stronger cytoprotective effect than apigenin possibly due to its higher MAPK, Nrf2 and UPR activation, and ROS scavenging activity. PMID:26087007

ERK and p38 MAPK-Activated Protein Kinases: a Family of Protein Kinases with Diverse Biological Functions

PubMed Central

Roux, Philippe P.; Blenis, John

2004-01-01

Conserved signaling pathways that activate the mitogen-activated protein kinases (MAPKs) are involved in relaying extracellular stimulations to intracellular responses. The MAPKs coordinately regulate cell proliferation, differentiation, motility, and survival, which are functions also known to be mediated by members of a growing family of MAPK-activated protein kinases (MKs; formerly known as MAPKAP kinases). The MKs are related serine/threonine kinases that respond to mitogenic and stress stimuli through proline-directed phosphorylation and activation of the kinase domain by extracellular signal-regulated kinases 1 and 2 and p38 MAPKs. There are currently 11 vertebrate MKs in five subfamilies based on primary sequence homology: the ribosomal S6 kinases, the mitogen- and stress-activated kinases, the MAPK-interacting kinases, MAPK-activated protein kinases 2 and 3, and MK5. In the last 5 years, several MK substrates have been identified, which has helped tremendously to identify the biological role of the members of this family. Together with data from the study of MK-knockout mice, the identities of the MK substrates indicate that they play important roles in diverse biological processes, including mRNA translation, cell proliferation and survival, and the nuclear genomic response to mitogens and cellular stresses. In this article, we review the existing data on the MKs and discuss their physiological functions based on recent discoveries. PMID:15187187

Neomorphic Mutations in PIK3R1 Confer Sensitivity to MAPK Inhibitors due to Activation of ERK and JNK Pathways | Office of Cancer Genomics

Cancer.gov

In a recent publication in Cancer Cell, CTD2 investigators discovered that a known cancer-associated gain-of-function alteration in phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) results in novel protein activity that confers sensitivity to mitogen-activated protein kinase (MAPK) inhibitors. The PIK3R1 gene encodes the p85α regulatory subunit of PIK3. Under normal conditions, p85α suppresses PIK3 mediated activation of downstream pathways that promote cell growth and survival.

Arsenic trioxide mediates HAPI microglia inflammatory response and subsequent neuron apoptosis through p38/JNK MAPK/STAT3 pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mao, Jiamin

Arsenic is a widely distributed toxic metalloid all over the world. Inorganic arsenic species are supposed to affect astrocytic functions and to cause neuron apoptosis in CNS. Microglias are the key cell type involved in innate immune responses in CNS, and microglia activation has been linked to inflammation and neurotoxicity. In this study, using ELISA, we showed that Arsenic trioxide up-regulated the expression and secretion of IL-1β in a dose-dependent manner and a time-dependent manner in cultured HAPI microglia cells. The secretion of IL-1β caused the apoptosis of SH-SY5Y. These pro-inflammatory responses were inhibited by the STAT3 blocker, AG490 andmore » P38/JNK MAPK blockers SB202190, SP600125. Further, Arsenic trioxide exposure could induce phosphorylation and activation of STAT3, and the translocation of STAT3 from the cytosol to the nucleus in this HAPI microglia cell line. Thus, the STAT3 signaling pathway can be activated after Arsenic trioxide treatment. However, P38/JNK MAPK blockers SB202190, SP600125 also obviously attenuated STAT3 activation and transnuclear transport induced by Arsenic trioxide. In concert with these results, we highlighted that the secretion of IL-1β and STAT3 activation induced by Arsenic trioxide can be mediated by elevation of P38/JNK MAPK in HAPI microglia cells and then induced the toxicity of neurons. - Highlights: • Arsenic trioxide exposure induced expression of IL-β in HAPI microglia. • Arsenic trioxide exposure induced activation of MAPK pathways in HAPI microglia. • Arsenic trioxide exposure induced activation of STAT3 pathways in HAPI microglia. • The expression of IL-β though P38/JNK MAPK/STAT3 pathways in HAPI microglia.« less

Induction of Tca8113 tumor cell apoptosis by icotinib is associated with reactive oxygen species mediated p38-MAPK activation.

PubMed

Yang, Cailing; Yan, Jianguo; Yuan, Guoyan; Zhang, Yinghua; Lu, Derong; Ren, Mingxin; Cui, Weigang

2014-08-01

Icotinib, a selective EGFR tyrosine kinase inhibitor (EGFR-TKI), has been shown to exhibit anti-tumor activity against several tumor cell lines. However, the exact molecular mechanism of icotinib's anti-tumor effect remains unknown. This study aims to examine the zytotoxic effect of icotinib on Tca8113 cells and its potential molecular mechanism. Icotinib significantly resulted in dose-dependent cell death as determined by MTT assay, accompanied by increased levels of Bax and DNA fragmentation. Icotinib could also induce Reactive Oxygen Species (ROS) generation. Further studies confirmed that scavenging of reactive oxygen species by N-acetyl-L-cysteine (NAC), and pharmacological inhibition of MAPK reversed icotinib-induced apoptosis in Tca8113 cells. Our data provide evidence that icotinib induces apoptosis, possibly via ROS-mediated MAPK pathway in Tca8113 cells.

Secreted Aspartic Protease Cleavage of Candida albicans Msb2 Activates Cek1 MAPK Signaling Affecting Biofilm Formation and Oropharyngeal Candidiasis

PubMed Central

Chadha, Sonia; Tati, Swetha; Conti, Heather R.; Hube, Bernhard; Cullen, Paul J.; Edgerton, Mira

2012-01-01

Perception of external stimuli and generation of an appropriate response are crucial for host colonization by pathogens. In pathogenic fungi, mitogen activated protein kinase (MAPK) pathways regulate dimorphism, biofilm/mat formation, and virulence. Signaling mucins, characterized by a heavily glycosylated extracellular domain, a transmembrane domain, and a small cytoplasmic domain, are known to regulate various signaling pathways. In Candida albicans, the mucin Msb2 regulates the Cek1 MAPK pathway. We show here that Msb2 is localized to the yeast cell wall and is further enriched on hyphal surfaces. A msb2Δ/Δ strain formed normal hyphae but had biofilm defects. Cek1 (but not Mkc1) phosphorylation was absent in the msb2Δ/Δ mutant. The extracellular domain of Msb2 was shed in cells exposed to elevated temperature and carbon source limitation, concomitant with germination and Cek1 phosphorylation. Msb2 shedding occurred differentially in cells grown planktonically or on solid surfaces in the presence of cell wall and osmotic stressors. We further show that Msb2 shedding and Cek1 phosphorylation were inhibited by addition of Pepstatin A (PA), a selective inhibitor of aspartic proteases (Saps). Analysis of combinations of Sap protease mutants identified a sap8Δ/Δ mutant with reduced MAPK signaling along with defects in biofilm formation, thereby suggesting that Sap8 potentially serves as a major regulator of Msb2 processing. We further show that loss of either Msb2 (msb2Δ/Δ) or Sap8 (sap8Δ/Δ) resulted in higher C. albicans surface β-glucan exposure and msb2Δ/Δ showed attenuated virulence in a murine model of oral candidiasis. Thus, Sap-mediated proteolytic cleavage of Msb2 is required for activation of the Cek1 MAPK pathway in response to environmental cues including those that induce germination. Inhibition of Msb2 processing at the level of Saps may provide a means of attenuating MAPK signaling and reducing C. albicans virulence. PMID:23139737

AP-1 subunits: quarrel and harmony among siblings.

PubMed

Hess, Jochen; Angel, Peter; Schorpp-Kistner, Marina

2004-12-01

The AP-1 transcription factor is mainly composed of Jun, Fos and ATF protein dimers. It mediates gene regulation in response to a plethora of physiological and pathological stimuli, including cytokines, growth factors, stress signals, bacterial and viral infections, as well as oncogenic stimuli. Studies in genetically modified mice and cells have highlighted a crucial role for AP-1 in a variety of cellular events involved in normal development or neoplastic transformation causing cancer. However, emerging evidence indicates that the contribution of AP-1 to determination of cell fates critically depends on the relative abundance of AP-1 subunits, the composition of AP-1 dimers, the quality of stimulus, the cell type and the cellular environment. Therefore, AP-1-mediated regulation of processes such as proliferation, differentiation, apoptosis and transformation should be considered within the context of a complex dynamic network of signalling pathways and other nuclear factors that respond simultaneously.

Interactions between Sirt1 and MAPKs regulate astrocyte activation induced by brain injury in vitro and in vivo.

PubMed

Li, Dan; Liu, Nan; Zhao, Hai-Hua; Zhang, Xu; Kawano, Hitoshi; Liu, Lu; Zhao, Liang; Li, Hong-Peng

2017-03-29

Astrocyte activation is a hallmark of traumatic brain injury resulting in neurological dysfunction or death for an overproduction of inflammatory cytokines and glial scar formation. Both the silent mating type information (Sirt1) expression and mitogen-activated protein kinase (MAPK) signal pathway activation represent a promising therapeutic target for several models of neurodegenerative diseases. We investigated the potential effects of Sirt1 upregulation and MAPK pathway pharmacological inhibition on astrocyte activation in vitro and in vivo. Moreover, we attempted to confirm the underlying interactions between Sirt1 and MAPK pathways in astrocyte activation after brain injury. The present study employs an interleukin-1β (IL-1β) stimulated primary cortical astrocyte model in vitro and a nigrostriatal pathway injury model in vivo to mimic the astrocyte activation induced by traumatic brain injury. The activation of GFAP, Sirt1, and MAPK pathways were detected by Western blot; astrocyte morphological hypertrophy was assessed using immunofluorescence staining; in order to explore the neuroprotective effect of regulation Sirt1 expression and MAPK pathway activation, the motor and neurological function tests were assessed after injury. GFAP level and morphological hypertrophy of astrocytes are elevated after injury in vitro or in vivo. Furthermore, the expressions of phosphorylated extracellular regulated protein kinases (p-ERK), phosphorylated c-Jun N-terminal kinase (p-JNK), and phosphorylated p38 activation (p-p38) are upregulated, but the Sirt1 expression is downregulated. Overexpression of Sirt1 significantly increases the p-ERK expression and reduces the p-JNK and p-p38 expressions. Inhibition of ERK, JNK, or p38 activation respectively with their inhibitors significantly elevated the Sirt1 expression and attenuated the astrocyte activation. Both the overproduction of Sirt1 and inhibition of ERK, JNK, or p38 activation can alleviate the astrocyte activation

BLOC-2, AP-3, and AP-1 Proteins Function in Concert with Rab38 and Rab32 Proteins to Mediate Protein Trafficking to Lysosome-related Organelles*

PubMed Central

Bultema, Jarred J.; Ambrosio, Andrea L.; Burek, Carolyn L.; Di Pietro, Santiago M.

2012-01-01

Lysosome-related organelles (LROs) are synthesized in specialized cell types where they largely coexist with conventional lysosomes. Most of the known cellular transport machinery involved in biogenesis are ubiquitously expressed and shared between lysosomes and LROs. Examples of common components are the adaptor protein complex-3 (AP-3) and biogenesis of lysosome-related organelle complex (BLOC)-2. These protein complexes control sorting and transport of newly synthesized integral membrane proteins from early endosomes to both lysosomes and LROs such as the melanosome. However, it is unknown what factors cooperate with the ubiquitous transport machinery to mediate transport to LROs in specialized cells. Focusing on the melanosome, we show that the ubiquitous machinery interacts with cell type-specific Rab proteins, Rab38 and Rab32, to facilitate transport to the maturing organelle. BLOC-2, AP-3, and AP-1 coimmunoprecipitated with Rab38 and Rab32 from MNT-1 melanocytic cell extracts. BLOC-2, AP-3, AP-1, and clathrin partially colocalized with Rab38 and Rab32 by confocal immunofluorescence microscopy in MNT-1 cells. Rab38- and Rab32-deficient MNT-1 cells displayed abnormal trafficking and steady state levels of known cargoes of the BLOC-2, AP-3, and AP-1 pathways, the melanin-synthesizing enzymes tyrosinase and tyrosinase-related protein-1. These observations support the idea that Rab38 and Rab32 are the specific factors that direct the ubiquitous machinery to mediate transport from early endosomes to maturing LROs. Additionally, analysis of tyrosinase-related protein-2 and total melanin production indicates that Rab32 has unique functions that cannot be carried out by Rab38 in melanosome biogenesis. PMID:22511774

BLOC-2, AP-3, and AP-1 proteins function in concert with Rab38 and Rab32 proteins to mediate protein trafficking to lysosome-related organelles.

PubMed

Bultema, Jarred J; Ambrosio, Andrea L; Burek, Carolyn L; Di Pietro, Santiago M

2012-06-01

Lysosome-related organelles (LROs) are synthesized in specialized cell types where they largely coexist with conventional lysosomes. Most of the known cellular transport machinery involved in biogenesis are ubiquitously expressed and shared between lysosomes and LROs. Examples of common components are the adaptor protein complex-3 (AP-3) and biogenesis of lysosome-related organelle complex (BLOC)-2. These protein complexes control sorting and transport of newly synthesized integral membrane proteins from early endosomes to both lysosomes and LROs such as the melanosome. However, it is unknown what factors cooperate with the ubiquitous transport machinery to mediate transport to LROs in specialized cells. Focusing on the melanosome, we show that the ubiquitous machinery interacts with cell type-specific Rab proteins, Rab38 and Rab32, to facilitate transport to the maturing organelle. BLOC-2, AP-3, and AP-1 coimmunoprecipitated with Rab38 and Rab32 from MNT-1 melanocytic cell extracts. BLOC-2, AP-3, AP-1, and clathrin partially colocalized with Rab38 and Rab32 by confocal immunofluorescence microscopy in MNT-1 cells. Rab38- and Rab32-deficient MNT-1 cells displayed abnormal trafficking and steady state levels of known cargoes of the BLOC-2, AP-3, and AP-1 pathways, the melanin-synthesizing enzymes tyrosinase and tyrosinase-related protein-1. These observations support the idea that Rab38 and Rab32 are the specific factors that direct the ubiquitous machinery to mediate transport from early endosomes to maturing LROs. Additionally, analysis of tyrosinase-related protein-2 and total melanin production indicates that Rab32 has unique functions that cannot be carried out by Rab38 in melanosome biogenesis.

Deferoxamine-mediated up-regulation of HIF-1α prevents dopaminergic neuronal death via the activation of MAPK family proteins in MPTP-treated mice.

PubMed

Guo, Chuang; Hao, Li-Juan; Yang, Zhao-Hui; Chai, Rui; Zhang, Shuai; Gu, Yu; Gao, Hui-Ling; Zhong, Man-Li; Wang, Tao; Li, Jia-Yi; Wang, Zhan-You

2016-06-01

Accumulating evidence suggests that an abnormal accumulation of iron in the substantia nigra (SN) is one of the defining characteristics of Parkinson's disease (PD). Accordingly, the potential neuroprotection of Fe chelators is widely acknowledged for the treatment of PD. Although desferrioxamine (DFO), an iron chelator widely used in clinical settings, has been reported to improve motor deficits and dopaminergic neuronal survival in animal models of PD, DFO has poor penetration to cross the blood-brain barrier and elicits side effects. We evaluated whether an intranasal administration of DFO improves the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced degeneration of dopaminergic neurons in the nigrostriatal axis and investigated the molecular mechanisms of intranasal DFO treatment in preventing MPTP-induced neurodegeneration. Treatment with DFO efficiently alleviated behavioral deficits, increased the survival of tyrosine hydroxylase (TH)-positive neurons, and decreased the action of astrocytes in the SN and striatum in an MPTP-induced PD mouse model. Interestingly, we found that DFO up-regulated the expression of HIF-1α protein, TH, vascular endothelial growth factor (VEGF), and growth associated protein 43 (GAP43) and down-regulated the expression of α-synuclein, divalent metal transporter with iron-responsive element (DMT1+IRE), and transferrin receptor (TFR). This was accompanied by a decrease in iron-positive cells in the SN and striatum of the DFO-treated group. We further revealed that DFO treatment significantly inhibited the MPTP-induced phosphorylation of the c-Jun N-terminal kinase (JNK) and differentially enhanced the phosphorylation of extracellular regulated protein kinases (ERK) and mitogen-activated protein kinase (MAPK)/P38 kinase. Additionally, the effects of DFO on increasing the Bcl-2/Bax ratio were further validated in vitro and in vivo. In SH-SY5Y cells, the DFO-mediated up-regulation of HIF-1α occurred via the activation of

Fisetin Protects PC12 Cells from Tunicamycin-Mediated Cell Death via Reactive Oxygen Species Scavenging and Modulation of Nrf2-Driven Gene Expression, SIRT1 and MAPK Signaling in PC12 Cells

PubMed Central

Yen, Jui-Hung; Wu, Pei-Shan; Chen, Shu-Fen; Wu, Ming-Jiuan

2017-01-01

Background: Fisetin (3,7,3′,4′-tetrahydroxyflavone) is a dietary flavonol and exhibits antioxidant, anti-inflammatory, and neuroprotective activities. However, high concentration of fisetin is reported to produce reactive oxygen species (ROS), induce endoplasmic reticulum (ER) stress and cause cytotoxicity in cancer cells. The aim of this study is to investigate the cytoprotective effects of low concentration of fisetin against tunicamycin (Tm)-mediated cytotoxicity in neuronal-like catecholaminergic PC12 cells. Methods: Cell viability was assayed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and apoptotic and autophagic markers were analyzed by Western blot. Gene expression of unfolded protein response (UPR) and Phase II enzymes was further investigated using RT-Q-PCR or Western blotting. Intracellular ROS level was measured using 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) by a fluorometer. The effects of fisetin on mitogen activated protein kinases (MAPKs) and SIRT1 (Sirtuin 1) signaling pathways were examined using Western blotting and specific inhibitors. Results: Fisetin (<20 µM) restored cell viability and repressed apoptosis, autophagy and ROS production in Tm-treated cells. Fisetin attenuated Tm-mediated expression of ER stress genes, such as glucose-regulated proteins 78 (GRP78), C/EBP homologous protein (CHOP also known as GADD153) and Tribbles homolog 3 (TRB3), but induced the expression of nuclear E2 related factor (Nrf)2-targeted heme oxygenase (HO)-1, glutamate cysteine ligase (GCL) and cystine/glutamate transporter (xCT/SLC7A11), in both the presence and absence of Tm. Moreover, fisetin enhanced phosphorylation of ERK (extracellular signal-regulated kinase), JNK (c-JUN NH2-terminal protein kinase), and p38 MAPK. Addition of JNK and p38 MAPK inhibitor significantly antagonized its cytoprotective activity and modulatory effects on UPR. Fisetin also restored Tm-inhibited SIRT1 expression and addition of

Cross-talk between NADPH oxidase-PKCα-p(38)MAPK and NF-κB-MT1MMP in activating proMMP-2 by ET-1 in pulmonary artery smooth muscle cells.

PubMed

Sarkar, Jaganmay; Chowdhury, Animesh; Chakraborti, Tapati; Chakraborti, Sajal

2016-04-01

Treatment of bovine pulmonary artery smooth muscle cells with endothelin-1 (ET-1) caused an increase in the expression and activation of proMMP-2 in the cells. The present study was undertaken to determine the underlying mechanisms involved in this scenario. We demonstrated that (i) pretreatment with NADPH oxidase inhibitor, apocynin; PKC-α inhibitor, Go6976; p(38)MAPK inhibitor SB203580 and NF-κB inhibitor, Bay11-7082 inhibited the expression and activation of proMMP-2 induced by ET-1; (ii) ET-1 treatment to the cells stimulated NADPH oxidase and PKCα activity, p(38)MAPK phosphorylation as well as NF-κB activation by translocation of NF-κBp65 subunit from cytosol to the nucleus, and subsequently by increasing its DNA-binding activity; (iii) ET-1 increases MT1-MMP expression, which was inhibited upon pretreatment with apocynin, Go6976, SB293580, and Bay 11-7082; (iv) ET-1 treatment to the cells downregulated TIMP-2 level. Although apocynin and Go6976 pretreatment reversed ET-1 effect on TIMP-2 level, yet pretreatment of the cells with SB203580 and Bay 11-7082 did not show any discernible change in TIMP-2 level by ET-1. Overall, our results suggest that ET-1-induced activation of proMMP-2 is mediated via cross-talk between NADPH oxidase-PKCα-p(38)MAPK and NFκB-MT1MMP signaling pathways along with a marked decrease in TIMP-2 expression in the cells.

Paeoniflorin protects against ischemia-induced brain damages in rats via inhibiting MAPKs/NF-κB-mediated inflammatory responses.

PubMed

Guo, Ruo-Bing; Wang, Guo-Feng; Zhao, An-Peng; Gu, Jun; Sun, Xiu-Lan; Hu, Gang

2012-01-01

Paeoniflorin (PF), the principal component of Paeoniae Radix prescribed in traditional Chinese medicine, has been reported to exhibit many pharmacological effects including protection against ischemic injury. However, the mechanisms underlying the protective effects of PF on cerebral ischemia are still under investigation. The present study showed that PF treatment for 14 days could significantly inhibit transient middle cerebral artery occlusion (MCAO)-induced over-activation of astrocytes and microglia, and prevented up-regulations of pro-inflamamtory mediators (TNFα, IL-1β, iNOS, COX(2) and 5-LOX) in plasma and brain. Further study demonstrated that chronic treatment with PF suppressed the activations of JNK and p38 MAPK, but enhanced ERK activation. And PF could reverse ischemia-induced activation of NF-κB signaling pathway. Moreover, our in vitro study revealed that PF treatment protected against TNFα-induced cell apoptosis and neuronal loss. Taken together, the present study demonstrates that PF produces a delayed protection in the ischemia-injured rats via inhibiting MAPKs/NF-κB mediated peripheral and cerebral inflammatory response. Our study reveals that PF might be a potential neuroprotective agent for stroke.

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

PubMed Central

Li, Qian; Zhang, Xuchen; Liang, Xitong; Zhang, Fang; Wang, Lianzhang; Zhong, Yi

2016-01-01

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

Mechanism of uptake of ZnO nanoparticles and inflammatory responses in macrophages require PI3K mediated MAPKs signaling.

PubMed

Roy, Ruchi; Parashar, Vyom; Chauhan, L K S; Shanker, Rishi; Das, Mukul; Tripathi, Anurag; Dwivedi, Premendra Dhar

2014-04-01

The inflammatory responses after exposure to zinc oxide nanoparticles (ZNPs) are known, however, the molecular mechanisms and direct consequences of particle uptake are still unclear. Dose and time-dependent increase in the uptake of ZNPs by macrophages has been observed by flow cytometry. Macrophages treated with ZNPs showed a significantly enhanced phagocytic activity. Inhibition of different internalization receptors caused a reduction in uptake of ZNPs in macrophages. The strongest inhibition in internalization was observed by blocking clathrin, caveolae and scavenger receptor mediated endocytic pathways. However, FcR and complement receptor-mediated phagocytic pathways also contributed significantly to control. Further, exposure of primary macrophages to ZNPs (2.5 μg/ml) caused (i) significant enhancement of Ras, PI3K, (ii) enhanced phosphorylation and subsequent activation of its downstream signaling pathways via ERK1/2, p38 and JNK MAPKs (iii) overexpression of c-Jun, c-Fos and NF-κB. Our results demonstrate that ZNPs induce the generation of reactive nitrogen species and overexpression of Cox-2, iNOS, pro-inflammatory cytokines (IL-6, IFN-γ, TNF-α, IL-17 and regulatory cytokine IL-10) and MAPKs which were found to be inhibited after blocking internalization of ZNPs through caveolae receptor pathway. These results indicate that ZNPs are internalized through caveolae pathway and the inflammatory responses involve PI3K mediated MAPKs signaling cascade. Copyright © 2013 Elsevier Ltd. All rights reserved.

Active lipids of Ganoderma lucidum spores-induced apoptosis in human leukemia THP-1 cells via MAPK and PI3K pathways.

PubMed

Wang, Jia-He; Zhou, Yi-Jun; Zhang, Meng; Kan, Liang; He, Ping

2012-01-31

Ganoderma lucidum (Lingzhi) is traditionally drug, which has been traditionally effective used in the treatment of chronic hepatopathy, hypertension, hyperglycemia and cancer. THP-1 and HL-60 apoptosis induced by active lipids of Ganoderma lucidum spores was quantified by flow cytometry using FITC-conjugated annexin V and PI; MAPK and Akt were measured by Western blot, and caspase-3, -8 and -9 activities were also detected by spectrophotometric assay. Our results showed that active lipids of Ganoderma lucidum spores decreased phosphorylation-ERK1/2 (P-ERK1/2), P-Akt and increased P-JNK1/2, but did not affect expressions of P-p38 MAPK in THP-1 cells. Moreover, treatment of THP-1 cells with active lipids of Ganoderma lucidum spores resulted in activation of caspase-3, -8 and -9. Furthermore, LY294002 (Akt inhibitor) or PD98059 (ERK1/2 inhibitor) significantly enhanced active lipids of Ganoderma lucidum spores-induced apoptosis in THP-1 cells, whereas caspase inhibitors or SP600125 (JNK inhibitor), decreased apoptosis in THP-1 cells. Taken together, our study for the first time suggests that active lipids of Ganoderma lucidum spores is able to enhance apoptosis in THP-1 cells, at least in part, through inhibition of ERK1/2, Akt and activation of JNK1/2 signaling pathways. Moreover, it also triggers caspase-3, -8 and -9 activation mediated apoptotic induction. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

N-n-butyl Haloperidol Iodide Protects against Hypoxia/Reoxygenation Injury in Cardiac Microvascular Endothelial Cells by Regulating the ROS/MAPK/Egr-1 Pathway

PubMed Central

Lu, Shishi; Zhang, Yanmei; Zhong, Shuping; Gao, Fenfei; Chen, Yicun; Li, Weiqiu; Zheng, Fuchun; Shi, Ganggang

2017-01-01

Endothelium dysfunction induced by reactive oxygen species (ROS) is an important initial event at the onset of myocardial ischemia/reperfusion in which the Egr-1 transcription factor often serves as a master switch for various damage pathways following reperfusion injury. We hypothesized that an intracellular ROS/MAPK/Egr-1 signaling pathway is activated in cardiac microvascular endothelial cells (CMECs) following hypoxia/reoxygenation (H/R). ROS generation, by either H/R or the ROS donor xanthine oxidase-hypoxanthine (XO/HX) activated all three MAPKs (ERK1/2, JNK, p38), and induced Egr-1 expression and Egr-1 DNA-binding activity in CMECs, whereas ROS scavengers (EDA and NAC) had the opposite effect following H/R. Inhibitors of all three MAPKs individually inhibited induction of Egr-1 expression by H/R in CMECs. Moreover, N-n-butyl haloperidol (F2), previously shown to protect cardiomyocytes subjected to I/R, dose-dependently downregulated H/R-induced ROS generation, MAPK activation, and Egr-1 expression and activity in CMECs, whereas XO/HX and MAPK activators (EGF, anisomycin) antagonized the effects of F2. Inhibition of the ROS/MAPK/Egr-1 signaling pathway, by either F2, NAC, or inhibition of MAPK, increased CMEC viability and the GSH/GSSG ratio, and decreased Egr-1 nuclear translocation. These results show that the ROS/MAPK/Egr-1 signaling pathway mediates H/R injury in CMECs, and F2 blocks this pathway to protect against H/R injury and further alleviate myocardial I/R injury. PMID:28111550

IKKα contributes to UVB-induced VEGF expression by regulating AP-1 transactivation

PubMed Central

Dong, Wen; Li, Yi; Gao, Ming; Hu, Meiru; Li, Xiaoguang; Mai, Sanyue; Guo, Ning; Yuan, Shengtao; Song, Lun

2012-01-01

Exposure to ultraviolet B (UVB) irradiation from sunlight induces the upregulation of VEGF, a potent angiogenic factor that is critical for mediating angiogenesis-associated photodamage. However, the molecular mechanisms related to UVB-induced VEGF expression have not been fully defined. Here, we demonstrate that one of the catalytic subunits of the IκB kinase complex (IKK), IKKα, plays a critical role in mediating UVB-induced VEGF expression in mouse embryonic fibroblasts (MEFs), which requires IKKα kinase activity but is independent of IKKβ, IKKγ and the transactivation of NF-κB. We further show that the transcriptional factor AP-1 functions as the downstream target of IKKα that is responsible for VEGF induction under UVB exposure. Both the accumulation of AP-1 component, c-Fos and the transactivation of AP-1 by UVB require the activated IKKα located within the nucleus. Moreover, nuclear IKKα can associate with c-Fos and recruit to the vegf promoter regions containing AP-1-responsive element and then trigger phosphorylation of the promoter-bound histone H3. Thus, our results have revealed a novel independent role for IKKα in controlling VEGF expression during the cellular UVB response by regulating the induction of the AP-1 component and phosphorylating histone H3 to facilitate AP-1 transactivation. Targeting IKKα shows promise for the prevention of UVB-induced angiogenesis and the associated photodamage. PMID:22169952

Involvement of p38 MAPK activation mediated through AT1 receptors on spinal astrocytes and neurons in angiotensin II- and III-induced nociceptive behavior in mice.

PubMed

Nemoto, Wataru; Ogata, Yoshiki; Nakagawasai, Osamu; Yaoita, Fukie; Tadano, Takeshi; Tan-No, Koichi

2015-12-01

We have previously demonstrated the possibility that angiotensin (Ang) II and its N-terminal metabolite Ang (1-7) act as neurotransmitters and/or neuromodulators in the spinal transmission of nociceptive information. Ang III, which is a C-terminal metabolite of Ang II, can also act on AT1 receptors, but its role in spinal nociceptive transmission remains unclear. Therefore, we examined the role of Ang III on the spinal nociceptive system in comparison with that of Ang II. Intrathecal (i.t.) administration of Ang III into mice produced a nociceptive behavior, which was dose-dependently inhibited by the co-administration of the AT1 receptor antagonist losartan and the p38 MAPK inhibitor SB203580, but not by the AT2 receptor antagonist PD123319, MEK1/2 inhibitor U0126 and JNK inhibitor SP600125. In addition, Ang III increased the phosphorylation of p38 MAPK in the dorsal lumbar spinal cord, which was inhibited by losartan. These effects were similar to those of observed with Ang II. The nociceptive behavior produced by Ang II or III was also attenuated by the administration of the astrocytic inhibitor L-α-aminoadipic acid, but not by the microglial inhibitor minocycline. Double immunohistochemical staining showed that spinal AT1 receptors were expressed on neurons and astrocytes, and that i.t. administration of either Ang II or III phosphorylated p38 MAPK in both spinal astrocytes and neurons. These results indicate that Ang III produces nociceptive behavior similar to Ang II, and suggest that the phosphorylation of p38 MAPK mediated through AT1 receptors on spinal astrocytes and neurons contributes to Ang II- and III-induced nociceptive behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biphasic and synergistic activation of p44mapk (ERK1) by growth factors: correlation between late phase activation and mitogenicity.

PubMed

Meloche, S; Seuwen, K; Pagès, G; Pouysségur, J

1992-05-01

We have examined the phosphorylation and protein kinase activity of p44 mitogen-activated protein kinase (p44mapk) in growth factor-stimulated hamster fibroblasts using a specific antiserum. The activity of p44mapk was stimulated both by receptor tyrosine kinases and G protein-coupled receptors. Detailed kinetics revealed that alpha-thrombin induces a biphasic activation of p44mapk in CCL39 cells: a rapid phase appearing at 5-10 min was followed by a late and sustained phase still elevated after 4 h. Inactivation of alpha-thrombin with hirudin after 30 sec, which prevented DNA synthesis, did not alter the early p44mapk response but completely abolished the late phase. Pretreatment of the cells with pertussis toxin, which inhibits by more than 95% alpha-thrombin-induced mitogenicity, resulted in the complete loss of late phase activity, while the early peak was partially attenuated. Treatment of CCL39 cells with basic fibroblast growth factor also induced a strong activation of p44mapk. Serotonin, which is not a mitogen by its own, had no effect on late phase p44mapk activity, but synergized with basic fibroblast growth factor to induce late kinase response and DNA synthesis. Both early and late phase activation of p44mapk were accompanied by tyrosine phosphorylation of the enzyme. Together, the results indicate that there is a very close correlation between the ability of a growth factor to induce late and sustained p44mapk activation and its mitogenic potential. Therefore, we propose that sustained p44mapk activation is an obligatory event for growth factor-induced cell cycle progression.

Redox-sensitive induction of Src/PI3-kinase/Akt and MAPKs pathways activate eNOS in response to EPA:DHA 6:1.

PubMed

Zgheel, Faraj; Alhosin, Mahmoud; Rashid, Sherzad; Burban, Mélanie; Auger, Cyril; Schini-Kerth, Valérie B

2014-01-01

Omega-3 fatty acid products containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have vasoprotective effects, in part, by stimulating the endothelial formation of nitric oxide (NO). This study determined the role of the EPA:DHA ratio and amount, and characterized the mechanism leading to endothelial NO synthase (eNOS) activation. EPA:DHA 6∶1 and 9∶1 caused significantly greater endothelium-dependent relaxations in porcine coronary artery rings than EPA:DHA 3∶1, 1∶1, 1∶3, 1∶6, 1∶9, EPA and DHA alone, and EPA:DHA 6∶1 with a reduced EPA + DHA amount, which were inhibited by an eNOS inhibitor. Relaxations to EPA:DHA 6∶1 were insensitive to cyclooxygenase inhibition, and reduced by inhibitors of either oxidative stress, Src kinase, PI3-kinase, p38 MAPK, MEK, or JNK. EPA:DHA 6∶1 induced phosphorylation of Src, Akt, p38 MAPK, ERK, JNK and eNOS; these effects were inhibited by MnTMPyP. EPA:DHA 6∶1 induced the endothelial formation of ROS in coronary artery sections as assessed by dihydroethidium, and of superoxide anions and hydrogen peroxide in cultured endothelial cells as assessed by electron spin resonance with the spin probe CMH, and the Amplex Red based assay, respectively. Omega-3 fatty acids cause endothelium-dependent NO-mediated relaxations in coronary artery rings, which are dependent on the EPA:DHA ratio and amount, and involve an intracellular activation of the redox-sensitive PI3-kinase/Akt and MAPKs pathways to activate eNOS.

The mucin MUC4 is a transcriptional and post-transcriptional target of K-ras oncogene in pancreatic cancer. Implication of MAPK/AP-1, NF-κB and RalB signaling pathways.

PubMed

Vasseur, Romain; Skrypek, Nicolas; Duchêne, Belinda; Renaud, Florence; Martínez-Maqueda, Daniel; Vincent, Audrey; Porchet, Nicole; Van Seuningen, Isabelle; Jonckheere, Nicolas

2015-12-01

The membrane-bound mucinMUC4 is a high molecularweight glycoprotein frequently deregulated in cancer. In pancreatic cancer, one of the most deadly cancers in occidental countries, MUC4 is neo-expressed in the preneoplastic stages and thereafter is involved in cancer cell properties leading to cancer progression and chemoresistance. K-ras oncogene is a small GTPase of the RAS superfamily, highly implicated in cancer. K-ras mutations are considered as an initiating event of pancreatic carcinogenesis and K-ras oncogenic activities are necessary components of cancer progression. However, K-ras remains clinically undruggable. Targeting early downstream K-ras signaling in cancer may thus appear as an interesting strategy and MUC4 regulation by K-ras in pancreatic carcinogenesis remains unknown. Using the Pdx1-Cre; LStopL-K-rasG12D mouse model of pancreatic carcinogenesis, we show that the in vivo early neo-expression of the mucin Muc4 in pancreatic intraepithelial neoplastic lesions (PanINs) induced by mutated K-ras is correlated with the activation of ERK, JNK and NF-κB signaling pathways. In vitro, transfection of constitutively activated K-rasG12V in pancreatic cancer cells led to the transcriptional upregulation of MUC4. This activation was found to be mediated at the transcriptional level by AP-1 and NF-κB transcription factors via MAPK, JNK and NF-κB pathways and at the posttranscriptional level by a mechanism involving the RalB GTPase. Altogether, these results identify MUC4 as a transcriptional and post-transcriptional target of K-ras in pancreatic cancer. This opens avenues in developing new approaches to target the early steps of this deadly cancer.

Estrogen suppresses breast cancer proliferation through GPER / p38 MAPK axis during hypoxia.

PubMed

Sathya, S; Sudhagar, S; Lakshmi, B S

2015-12-05

Breast cancer cells frequently experience hypoxia which is associated with resistance to hormonal therapy and poor clinical prognosis, making it important to understand the function of estrogen under hypoxic condition. Here, we demonstrate that estrogen suppresses breast cancer cell growth under hypoxia, through inhibition at G1/S phase of cell cycle, by elevation of p21 expression. The involvement of GPER in estrogen mediated growth arrest was elucidated using specific ligands and siRNA. Although, estrogen was observed to activate both p44/42 and p38 MAPK signaling, pharmacological inhibition and silencing of p38 MAPK abrogated the induction of p21 expression and growth arrest, during hypoxia. The involvement of estrogen induced ROS in the p38 MAPK mediated p21 expression and cell growth arrest was established by observing that scavenging of ROS by NAC abrogated p38 MAPK activation and p21 expression during hypoxia. In conclusion, Estrogen suppresses breast cancer growth by inhibiting G1/S phase transition through GPER/ROS/p38 MAPK/p21 mediated signaling during hypoxic condition. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Two distinct roles of mitogen-activated protein kinases in platelets and a novel Rac1-MAPK–dependent integrin outside-in retractile signaling pathway

PubMed Central

Flevaris, Panagiotis; Li, Zhenyu; Zhang, Guoying; Zheng, Yi; Liu, Junling

2009-01-01

Mitogen-activated protein kinases (MAPK), p38, and extracellular stimuli-responsive kinase (ERK), are acutely but transiently activated in platelets by platelet agonists, and the agonist-induced platelet MAPK activation is inhibited by ligand binding to the integrin αIIbβ3. Here we show that, although the activation of MAPK, as indicated by MAPK phosphorylation, is initially inhibited after ligand binding to integrin αIIbβ3, integrin outside-insignaling results in a late but sustained activation of MAPKs in platelets. Furthermore, we show that the early agonist-induced MAPK activation and the late integrin-mediated MAPK activation play distinct roles in different stages of platelet activation. Agonist-induced MAPK activation primarily plays an important role in stimulating secretion of platelet granules, while integrin-mediated MAPK activation is important in facilitating clot retraction. The stimulatory role of MAPK in clot retraction is mediated by stimulating myosin light chain (MLC) phosphorylation. Importantly, integrin-dependent MAPK activation, MAPK-dependent MLC phosphorylation, and clot retraction are inhibited by a Rac1 inhibitor and in Rac1 knockout platelets, indicating that integrin-induced activation of MAPK and MLC and subsequent clot retraction is Rac1-dependent. Thus, our results reveal 2 different activation mechanisms of MAPKs that are involved in distinct aspects of platelet function and a novel Rac1-MAPK–dependent cell retractile signaling pathway. PMID:18957688

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

PubMed

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

2018-01-01

Ultraviolet light-induced reactive oxygen species (ROS) damage human skin and prematurely cause aging. A growing body of research is focusing on considering plants and plant-derived compounds as antiphotoaging therapeutic material. Pterocarpus santalinus L., as an Indian traditional medicine, possesses antidiabetic, anti-inflammatory and antioxidative effects. Here, we studied the antiphotoaging effects of ethanolic extract of P. santalinus L. heartwood (EPS) on ultraviolet radiation B (UVB)-irradiated normal human dermal fibroblasts (NHDFs). Results showed that EPS significantly inhibited the upregulation of matrix metalloproteinases and IL-6 caused by UVB irradiation, and suppressed UVB-induced phosphorylation of extracellular signal-regulated kinase, Jun N-terminal kinase and p38, as well as the activation of AP-1 transcription factors. Further study indicated that UVB-induced production of MMP-1 and IL-6 could be inhibited by PD 98059 (an ERK inhibitor) and SP600125 (A JNK inhibitor), implied that EPS inhibited UVB-induced MMP-1 and IL-6 secretion by inactivating MAPK signaling pathway. In addition, EPS possessed an excellent antioxidant activity, which could increase cytoprotective antioxidants such as HO-1, NQ-O1 expression by facilitating the nuclear accumulation of Nrf2. Treatment of NHDFs with EPS also recovered UVB-induced procollagen type I reduction by activating TGF-β/Smad pathway. These findings demonstrated that EPS had a potential effect against UVB-induced skin photoaging. © 2017 The American Society of Photobiology.

Overactivation of Mitogen-Activated Protein Kinase and Suppression of Mitofusin-2 Expression Are Two Independent Events in High Mobility Group Box 1 Protein–Mediated T Cell Immune Dysfunction

PubMed Central

Tang, Lu-ming; Zhao, Guang-ju; Zhu, Xiao-mei; Dong, Ning; Yu, Yan

2013-01-01

High mobility group box 1 protein (HMGB1), a critical proinflammatory cytokine, has recently been identified to be an immunostimulatory signal involved in sepsis-related immune dysfunction when released extracellularly, but the potential mechanism involved remains elusive. Here, we showed that the treatment with HMGB1 in vitro inhibited T lymphocyte immune response and expression of mitofusin-2 (Mfn-2; a member of the mitofusin family) in a dose- and time-dependent manner. Upregulation of Mfn-2 expression attenuated the suppressive effect of HMGB1 on T cell immune function. The phosphorylation of both extracellular signal-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase (MAPK) was markedly upregulated by treating with high amount of HMGB1, while pretreatment with ERK1/2 and p38 MAPK-specific inhibitors (U0126 and SB203580) could attenuate suppression of T cell immune function and nuclear factor of activated T cell (NFAT) activation induced by HMGB1, respectively. HMGB1-induced activity of ERK1/2 and p38 was not fully inhibited in the presence of U0126 or SB203580. Interestingly, overexpression of Mfn-2 had no marked effect on HMGB1-mediated activation of MAPK, but could attenuate the suppressive effect of HMGB1 on the activity of NFAT. Thus, the mechanisms involved in HMGB1-induced T cell immune dysfunction in vitro at least partly include suppression of Mfn-2 expression, overactivation of ERK1/2, p38 MAPK, and intervention of NFAT activation, while the protective effect of Mfn-2 on T cell immune dysfunction induced by HMGB1 is dependent on other signaling pathway associated with NFAT, but not MAPK. Taken together, we conclude that overactivation of MAPK and suppression of Mfn-2 expression are two independent events in HMGB1-mediated T cell immune dysfunction. PMID:23697559

Tat-CBR1 inhibits inflammatory responses through the suppressions of NF-κB and MAPK activation in macrophages and TPA-induced ear edema in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Young Nam; Kim, Dae Won; Jo, Hyo Sang

Human carbonyl reductase 1 (CBR1) plays a crucial role in cell survival and protects against oxidative stress response. However, its anti-inflammatory effects are not yet clearly understood. In this study, we examined whether CBR1 protects against inflammatory responses in macrophages and mice using a Tat-CBR1 protein which is able to penetrate into cells. The results revealed that purified Tat-CBR1 protein efficiently transduced into Raw 264.7 cells and inhibited lipopolysaccharide (LPS)-induced cyclooxygenase-2 (COX-2), nitric oxide (NO) and prostaglandin E{sub 2} (PGE{sub 2}) expression levels. In addition, Tat-CBR1 protein leads to decreased pro-inflammatory cytokine expression through suppression of nuclear transcription factor-kappaB (NF-κB)more » and mitogen activated protein kinase (MAPK) activation. Furthermore, Tat-CBR1 protein inhibited inflammatory responses in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation when applied topically. These findings indicate that Tat-CBR1 protein has anti-inflammatory properties in vitro and in vivo through inhibition of NF-κB and MAPK activation, suggesting that Tat-CBR1 protein may have potential as a therapeutic agent against inflammatory diseases. - Highlights: • Transduced Tat-CBR1 reduces LPS-induced inflammatory mediators and cytokines. • Tat-CBR1 inhibits MAPK and NF-κB activation. • Tat-CBR1 ameliorates inflammation response in vitro and in vivo. • Tat-CBR1 may be useful as potential therapeutic agent for inflammation.« less

Effect of mitogen-activated protein kinases on chemokine synthesis induced by substance P in mouse pancreatic acinar cells

PubMed Central

Ramnath, Raina Devi; Sun, Jia; Adhikari, Sharmila; Bhatia, Madhav

2007-01-01

Abstract Substance P, acting via its neurokinin 1 receptor (NK1 R), plays an important role in mediating a variety of inflammatory processes. Its interaction with chemokines is known to play a crucial role in the pathogenesis of acute pancreatitis. In pancreatic acinar cells, substance P stimulates the release of NFκB-driven chemokines. However, the signal transduction pathways by which substance P-NK1 R interaction induces chemokine production are still unclear. To that end, we went on to examine the participation of mitogen-activated protein kinases (MAPKs) in substance P-induced synthesis of pro-inflammatory chemokines, monocyte chemoanractant protein-1 (MCP-I), macrophage inflammatory protein-lα (MIP-lα) and macrophage inflammatory protein-2 (MIP-2), in pancreatic acini. In this study, we observed a time-dependent activation of ERK1/2, c-Jun N-terminal kinase (JNK), NFκB and activator protein-1 (AP-1) when pancreatic acini were stimulated with substance P. Moreover, substance P-induced ERK 1/2, JNK, NFκB and AP-1 activation as well as chemokine synthesis were blocked by pre-treatment with either extracellular signal-regulated protein kinase kinase 1 (MEK1) inhibitor or JNK inhibitor. In addition, substance P-induced activation of ERK 112, JNK, NFκB and AP-1-driven chemokine production were attenuated by CP96345, a selective NK1 R antagonist, in pancreatic acinar cells. Taken together, these results suggest that substance P-NK1 R induced chemokine production depends on the activation of MAPKs-mediated NFκB and AP-1 signalling pathways in mouse pancreatic acini. PMID:18205703

Differential signaling mechanism for HIV-1 Nef-mediated production of IL-6 and IL-8 in human astrocytes.

PubMed

Liu, Xun; Kumar, Anil

2015-06-15

Variety of HIV-1 viral proteins including HIV-1 Nef are known to activate astrocytes and microglia in the brain and cause the release of pro-inflammatory cytokines, which is thought to be one of the mechanisms leading to HIV-1- mediated neurotoxicity. IL-6 and IL-8 have been found in the CSF of patients with HIV-1 associated dementia (HAD), suggesting that they might play important roles in HIV-1 neuropathology. In the present study we examined the effects of HIV-1 Nef on IL-6 and IL-8 induction in astrocytes. The results demonstrate that both IL-6 and IL-8 are significantly induced in HIV-1 Nef-transfected SVGA astrocytes and HIV-1 Nef-treated primary fetal astrocytes. We also determined the molecular mechanisms responsible for the HIV-1 Nef-induced increased IL-6 and IL-8 by using chemical inhibitors and siRNAs against PI3K/Akt/PKC, p38 MAPK, NF-κB, CEBP and AP-1. Our results clearly demonstrate that the PI3K/PKC, p38 MAPK, NF-κB and AP-1 pathways are involved in HIV-1 Nef-induced IL-6 production in astrocytes, while PI3K/PKC and NF-κB pathways are involved in HIV-1 Nef-induced IL-8 production. These results offer new potential targets to develop therapeutic strategy for treatment of HIV-1 associated neurological disorders, prevalent in > 40% of individuals infected with HIV-1.

IL-1β-induced and p38MAPK-dependent activation of the mitogen-activated protein kinase-activated protein kinase 2 (MK2) in hepatocytes: Signal transduction with robust and concentration-independent signal amplification

PubMed Central

Kulawik, Andreas; Engesser, Raphael; Ehlting, Christian; Raue, Andreas; Albrecht, Ute; Hahn, Bettina; Lehmann, Wolf-Dieter; Gaestel, Matthias; Klingmüller, Ursula; Häussinger, Dieter; Timmer, Jens; Bode, Johannes G.

2017-01-01

The IL-1β induced activation of the p38MAPK/MAPK-activated protein kinase 2 (MK2) pathway in hepatocytes is important for control of the acute phase response and regulation of liver regeneration. Many aspects of the regulatory relevance of this pathway have been investigated in immune cells in the context of inflammation. However, very little is known about concentration-dependent activation kinetics and signal propagation in hepatocytes and the role of MK2. We established a mathematical model for IL-1β-induced activation of the p38MAPK/MK2 pathway in hepatocytes that was calibrated to quantitative data on time- and IL-1β concentration-dependent phosphorylation of p38MAPK and MK2 in primary mouse hepatocytes. This analysis showed that, in hepatocytes, signal transduction from IL-1β via p38MAPK to MK2 is characterized by strong signal amplification. Quantification of p38MAPK and MK2 revealed that, in hepatocytes, at maximum, 11.3% of p38MAPK molecules and 36.5% of MK2 molecules are activated in response to IL-1β. The mathematical model was experimentally validated by employing phosphatase inhibitors and the p38MAPK inhibitor SB203580. Model simulations predicted an IC50 of 1–1.2 μm for SB203580 in hepatocytes. In silico analyses and experimental validation demonstrated that the kinase activity of p38MAPK determines signal amplitude, whereas phosphatase activity affects both signal amplitude and duration. p38MAPK and MK2 concentrations and responsiveness toward IL-1β were quantitatively compared between hepatocytes and macrophages. In macrophages, the absolute p38MAPK and MK2 concentration was significantly higher. Finally, in line with experimental observations, the mathematical model predicted a significantly higher half-maximal effective concentration for IL-1β-induced pathway activation in macrophages compared with hepatocytes, underscoring the importance of cell type-specific differences in pathway regulation. PMID:28223354

15-LO/15-HETE mediated vascular adventitia fibrosis via p38 MAPK-dependent TGF-β.

PubMed

Zhang, Li; Li, Yumei; Chen, Minggang; Su, Xiaojie; Yi, Dan; Lu, Ping; Zhu, Daling

2014-02-01

15-Lipoxygenase/15-hydroxyeicosatetraenoic acid (15-LO/15-HETE) is known to modulate pulmonary vascular medial hypertrophy and intimal endothelial cells migration and angiogenesis after hypoxia. However, it is unclear whether 15-HETE affects the adventitia of the pulmonary arterial wall. We performed immunohistochemistry, adventitia fibrosis, pulmonary artery fibroblasts phenotype and extracellular matrix (ECM) deposition to determine the role of 15-HETE in hypoxia-induced pulmonary vascular adventitia remodeling. Our studies showed that O2 deprivation induced adventitia hypertrophy of pulmonary arteries with ECM accumulation in both humans with pulmonary arterial hypertension and hypoxic rats. Hypoxia induced 15-LO expression in adventitia. With the inhibitor, NDGA depressed the hypoxia induced ECM deposition and 15-LO production in hypoxic rats. Hypoxia up-regulated the expression of α-SMA, type-Ia collagen and fibronectin in cultured fibroblasts, which seemed to be due to the increased 15-LO/15-HETE. Exogenous 15-HETE mediated the ECM and phenotypic alterations of the fibroblasts as well. The 15-LO/15-HETE induced adventitia fibrosis and fibroblasts phenotypic alterations depended on signaling of the transforming growth factor-β1 (TGF-β1)/Smad2/3 pathway. P38 mitogen-activated protein kinase (p38 MAPKs) was likely to mediate 15-LO induced TGF-β1 and Smad2/3 activation after hypoxia. The results suggest that adventitia fibrosis is an important event in the hypoxia induced pulmonary arterial remodeling, which relies on 15-LO/15-HETE induced p38 MAPK-dependent TGF-β1/Smad2/3 intracellular signaling systems. © 2013 Wiley Periodicals, Inc.

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

Glutamate increases pancreatic cancer cell invasion and migration via AMPA receptor activation and Kras-MAPK signaling.

PubMed

Herner, Alexander; Sauliunaite, Danguole; Michalski, Christoph W; Erkan, Mert; De Oliveira, Tiago; Abiatari, Ivane; Kong, Bo; Esposito, Irene; Friess, Helmut; Kleeff, Jörg

2011-11-15

Glutamate has been implicated in tumorigenesis through activation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors (AMPAR). However, the function of a glutamate-to-AMPAR signal in pancreatic ductal adenocarcinoma (PDAC) has remained elusive. We now show that glutamate-mediated AMPA receptor activation increases invasion and migration of pancreatic cancer cells via activation of the classical MAPK pathway. Glutamate levels were increased in pancreatic cancer accompanied by downregulation of GluR subunits 1, 2, and 4. In pancreatic cancer precursor lesions, pancreatic intraepithelial neoplasia (PanIN), GluR1 subunit levels were strikingly and step-wise increased but its expression was rare in PDAC. Pharmacological inhibition or RNAi-mediated suppression of GluR1 or GluR2 did not affect cancer cell growth but significantly decreased invasion. In a K-ras wildtype cell line, AMPA receptor activation enhanced K-ras activity and--further downstream--phosphorylation of p38 and of p44/42. Preemptive blockade of AMPA receptors in a mouse model of pancreatic cancer inhibited tumor cell settling. AMPA receptor activation thus not only activates MAPK signalling but also directly increases activity of K-ras. Glutamate might serve as a molecular switch that decreases the threshold of K-ras-induced oncogenic signalling and increases the chance of malignant transformation of pancreatic cancer precursor lesions. Copyright © 2011 UICC.

Fructose-1,6-bisphosphatase Inhibits ERK Activation and Bypasses Gemcitabine Resistance in Pancreatic Cancer by Blocking IQGAP1–MAPK Interaction

PubMed Central

Jin, Xin; Pan, Yunqian; Wang, Liguo; Ma, Tao; Zhang, Lizhi; Tang, Amy H.; Billadeau, Daniel D.; Wu, Heshui; Huang, Haojie

2017-01-01

Dysregulation of the MAPK pathway correlates with progression of pancreatic ductal adenocarcinoma (PDAC) progression. IQ motif containing GTPase-activating protein 1 (IQGAP1) is a MAPK scaffold that directly regulates the activation of RAF, MEK, and ERK. Fructose-1,6-bisphosphatase (FBP1), a key enzyme in gluconeogenesis, is transcriptionally downregulated in various cancers, including PDAC. Here, we demonstrate that FBP1 acts as a negative modulator of the IQGAP1–MAPK signaling axis in PDAC cells. FBP1 binding to the WW domain of IQGAP1 impeded IQGAP1-dependent ERK1/2 phosphorylation (pERK1/2) in a manner independent of FBP1 enzymatic activity. Conversely, decreased FBP1 expression induced pERK1/2 levels in PDAC cell lines and correlated with increased pERK1/2 levels in patient specimens. Treatment with gemcitabine caused undesirable activation of ERK1/2 in PDAC cells, but cotreatment with the FBP1-derived small peptide inhibitor FBP1 E4 overcame gemcitabine-induced ERK activation, thereby increasing the anticancer efficacy of gemcitabine in PDAC. These findings identify a primary mechanism of resistance of PDAC to standard therapy and suggest that the FBP1–IQGAP1–ERK1/2 signaling axis can be targeted for effective treatment of PDAC. PMID:28720574

Redox-Sensitive Induction of Src/PI3-kinase/Akt and MAPKs Pathways Activate eNOS in Response to EPA:DHA 6:1

PubMed Central

Zgheel, Faraj; Alhosin, Mahmoud; Rashid, Sherzad; Burban, Mélanie; Auger, Cyril; Schini-Kerth, Valérie B.

2014-01-01

Aims Omega-3 fatty acid products containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have vasoprotective effects, in part, by stimulating the endothelial formation of nitric oxide (NO). This study determined the role of the EPA:DHA ratio and amount, and characterized the mechanism leading to endothelial NO synthase (eNOS) activation. Methods and Results EPA:DHA 6∶1 and 9∶1 caused significantly greater endothelium-dependent relaxations in porcine coronary artery rings than EPA:DHA 3∶1, 1∶1, 1∶3, 1∶6, 1∶9, EPA and DHA alone, and EPA:DHA 6∶1 with a reduced EPA + DHA amount, which were inhibited by an eNOS inhibitor. Relaxations to EPA:DHA 6∶1 were insensitive to cyclooxygenase inhibition, and reduced by inhibitors of either oxidative stress, Src kinase, PI3-kinase, p38 MAPK, MEK, or JNK. EPA:DHA 6∶1 induced phosphorylation of Src, Akt, p38 MAPK, ERK, JNK and eNOS; these effects were inhibited by MnTMPyP. EPA:DHA 6∶1 induced the endothelial formation of ROS in coronary artery sections as assessed by dihydroethidium, and of superoxide anions and hydrogen peroxide in cultured endothelial cells as assessed by electron spin resonance with the spin probe CMH, and the Amplex Red based assay, respectively. Conclusion Omega-3 fatty acids cause endothelium-dependent NO-mediated relaxations in coronary artery rings, which are dependent on the EPA:DHA ratio and amount, and involve an intracellular activation of the redox-sensitive PI3-kinase/Akt and MAPKs pathways to activate eNOS. PMID:25133540

Repeated pulses of serotonin required for long-term facilitation activate mitogen-activated protein kinase in sensory neurons of Aplysia

PubMed Central

Michael, Dan; Martin, Kelsey C.; Seger, Rony; Ning, Ming-Ming; Baston, Rene; Kandel, Eric R.

1998-01-01

Long-term facilitation of the connections between the sensory and motor neurons of the gill-withdrawal reflex in Aplysia requires five repeated pulses of serotonin (5-HT). The repeated pulses of 5-HT initiate a cascade of gene activation that leads ultimately to the growth of new synaptic connections. Several genes in this process have been identified, including the transcriptional regulators apCREB-1, apCREB-2, apC/EBP, and the cell adhesion molecule apCAM, which is thought to be involved in the formation of new synaptic connections. Here we report that the transcriptional regulators apCREB-2 and apC/EBP, as well as a peptide derived from the cytoplasmic domain of apCAM, are phosphorylated in vitro by Aplysia mitogen-activated protein kinase (apMAPK). We have cloned the cDNA encoding apMAPK and show that apMAPK activity is increased in sensory neurons treated with repeated pulses of 5-HT and by the cAMP pathway. These results suggest that apMAPK may participate with cAMP-dependent protein kinase during long-term facilitation in sensory cells by modifying some of the key elements involved in the consolidation of short- to long-lasting changes in synaptic strength. PMID:9465108

Involvement of MAPKs, NF-{kappa}B and p300 co-activator in IL-1{beta}-induced cytosolic phospholipase A{sub 2} expression in canine tracheal smooth muscle cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, S.-F.; Lin, C.-C.; Chen, H.-C.

2008-11-01

Cytosolic phospholipase A{sub 2} (cPLA{sub 2}) plays a pivotal role in mediating agonist-induced arachidonic acid release for prostaglandin (PG) synthesis during stimulation with interleukin-1{beta} (IL-1{beta}). However, the mechanisms underlying IL-1{beta}-induced cPLA{sub 2} expression and PGE{sub 2} synthesis by canine tracheal smooth muscle cells (CTSMCs) have not been defined. IL-1{beta} induced cPLA{sub 2} protein and mRNA expression, PGE{sub 2} production, and phosphorylation of p42/p44 MAPK, p38 MAPK (ATF{sub 2}), and JNK (c-Jun) in a time- and concentration-dependent manner, determined by Western blotting, RT-PCR, and ELISA, which was attenuated by the inhibitors of MEK1/2 (U0126), p38 MAPK (SB202190), and JNK (SP600125), ormore » transfection with dominant negative mutants of MEK1/2, p38, and JNK, respectively. Furthermore, IL-1{beta}-induced cPLA{sub 2} expression and PGE{sub 2} synthesis was inhibited by a selective NF-{kappa}B inhibitor (helenalin) or transfection with dominant negative mutants of NF-{kappa}B inducing kinase (NIK), I{kappa}B kinase (IKK)-{alpha}, and IKK-{beta}. Consistently, IL-1{beta} stimulated both I{kappa}B-{alpha} degradation and NF-{kappa}B translocation into nucleus in these cells. NF-{kappa}B translocation was blocked by helenalin, but not by U0126, SB202190, and SP600125. MAPKs together with NF-{kappa}B-activated p300 recruited to cPLA{sub 2} promoter thus facilitating the binding of NF-{kappa}B to cPLA{sub 2} promoter region and expression of cPLA{sub 2} mRNA. IL-1{beta}-induced cPLA{sub 2} expression and PGE{sub 2} production was inhibited by actinomycin D and cycloheximide, indicating the involvement of transcriptional and translational events in these responses. These results suggest that in CTSMCs, IL-1{beta}-induced cPLA{sub 2} expression and PGE{sub 2} synthesis was independently mediated through activation of MAPKs and NF-{kappa}B pathways and was connected to p300 recruitment and activation.« less

Naringin induces autophagy-mediated growth inhibition by downregulating the PI3K/Akt/mTOR cascade via activation of MAPK pathways in AGS cancer cells.

PubMed

Raha, Suchismita; Yumnam, Silvia; Hong, Gyeong Eun; Lee, Ho Jeong; Saralamma, Venu Venkatarame Gowda; Park, Hyeon-Soo; Heo, Jeong Doo; Lee, Sang Joon; Kim, Eun Hee; Kim, Jin-A; Kim, Gon Sup

2015-09-01

Naringin, one of the major bioflavonoid of Citrus, has been demonstrated as potential anticancer agent. However, the underlying anticancer mechanism still needs to be explored further. This study investigated the inhibitory effect of Naringin on human AGS cancer cells. AGS cell proliferation was inhibited by Naringin in a dose- and time-dependent manner. Naringin did not induce apoptotic cell death, determined by no DNA fragmentation and the reduced Bax/Bcl-xL ratio. Growth inhibitory role of Naringin was observed by western blot analysis demonstrating downregulation of PI3K/Akt/mTOR cascade with an upregulated p21CIPI/WAFI. Formation of cytoplasmic vacuoles and autophagosomes were observed in Naringin-treated AGS cells, further confirmed by the activation of autophagic proteins Beclin 1 and LC3B with a significant phosphorylation of mitogen activated protein kinases (MAPKs). Collectively, our observed results determined that anti-proliferative activity of Naringin in AGS cancer cells is due to suppression of PI3K/Akt/mTOR cascade via induction of autophagy with activated MAPKs. Thus, the present finding suggests that Naringin induced autophagy- mediated growth inhibition shows potential as an alternative therapeutic agent for human gastric carcinoma.

Corticosteroids inhibit sphingosine 1-phosphate-induced interleukin-6 secretion from human airway smooth muscle via mitogen-activated protein kinase phosphatase 1-mediated repression of mitogen and stress-activated protein kinase 1.

PubMed

Che, Wenchi; Parmentier, Johannes; Seidel, Petra; Manetsch, Melanie; Ramsay, Emma E; Alkhouri, Hatem; Ge, Qi; Armour, Carol L; Ammit, Alaina J

2014-02-01

Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid that plays an important proinflammatory role in asthmatic airways. Corticosteroids are first-line antiinflammatories in asthma; however, their repressive effects on S1P-induced cytokine secretion have not been investigated. To address this, our in vitro study reveals the molecular mechanisms by which corticosteroids inhibit S1P-induced IL-6 expression in the pivotal immunomodulatory cell type, airway smooth muscle (ASM). We first uncover the cellular signaling pathways responsible: S1P activates a cyclic adenosine monophosphate/cAMP response-element-binding protein (CREB)/CRE-dependent pathway to induce IL-6 transcription, concomitant with stimulation of the mitogen-activated protein kinase (MAPK) superfamily and downstream mitogen and stress-activated protein kinase 1 (MSK1) and histone H3 phosphorylation. In this way, S1P stimulates parallel signaling pathways to induce IL-6 secretion via CRE-driven transcription of the IL-6 gene promoter in a relaxed chromatin environment achieved through histone H3 phosphorylation. Second, we investigated how corticosteroids mediate their repressive effects. The corticosteroid dexamethasone inhibits S1P-induced IL-6 protein secretion and mRNA expression, but CREB/CRE transrepression, inhibition of IL-6 mRNA stability, or subcellular relocation of MSK1 were not responsible for the repressive effects of dexamethasone. Rather, we show that dexamethasone rapidly induces up-regulation of the MAPK deactivator MAPK phosphatase 1 (MKP-1) and that MKP-1 blocks the MAPK-driven activation of MSK1 and phosphorylation of histone H3. This was confirmed by treatment with triptolide, an inhibitor of MKP-1 up-regulation, where repressive effects of corticosteroids were reversed. Our study reveals the molecular mechanism underlying the antiinflammatory capacity of corticosteroids to repress proinflammatory functions induced by the potent bioactive sphingolipid S1P in the lung.

Molecular Basis for Enhancement of the Meiotic DMCI Recombinase by RAD51AP1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dray, Eloise; Dunlop, Myun Hwa; Kauppi, Liisa

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 partnermore » 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.« less

Suppressive effects of Lithospermum erythrorhizon extracts on lipopolysaccharide-induced activation of AP-1 and NF-kappaB via mitogen-activated protein kinase pathways in mouse macrophage cells.

PubMed

Han, Kyu Yeon; Kwon, Taek Hwan; Lee, Tae Hoon; Lee, Sung-Joon; Kim, Sung-Hoon; Kim, Jiyoung

2008-04-30

A variety of anti-inflammatory agents have been shown to exert chemopreventive activity via targeting of transcription factors such as NF-kappaB and AP-1. Lithospermum erythrorhizon (LE) has long been used in traditional oriental medicine. In this study, we demonstrated the inhibitory effects of LE extracts on lipopolysaccharide (LPS)-stimulated production of inflammatory cytokines. As an underlying mechanism of inhibition, LE extracts reduced LPS-induced transactivation of AP-1 as well as NF-kappaB in mouse macrophage cells. Electrophoretic mobility shift assays indicated that LE extracts inhibited the DNA binding activities of AP-1 and NF-kappaB. In addition, phosphorylation of IkappaB-alpha protein was suppressed by LE extracts. Moreover, LE extracts inhibited c-Jun N-terminal kinase and extracellular signal-regulated signaling pathways. Our results suggest that the anti-inflammatory activity of LE extracts may be mediated by the inhibition of signal transduction pathways that normally lead to the activation of AP-1and NF-kappaB. These inhibitory effects may be useful for chemoprevention of cancer or other chronic inflammatory diseases.

The CDK4/6 inhibitor LY2835219 overcomes vemurafenib resistance resulting from MAPK reactivation and cyclin D1 upregulation.

PubMed

Yadav, Vipin; Burke, Teresa F; Huber, Lysiane; Van Horn, Robert D; Zhang, Youyan; Buchanan, Sean G; Chan, Edward M; Starling, James J; Beckmann, Richard P; Peng, Sheng-Bin

2014-10-01

B-RAF selective inhibitors, including vemurafenib, were recently developed as effective therapies for melanoma patients with B-RAF V600E mutation. However, most patients treated with vemurafenib eventually develop resistance largely due to reactivation of MAPK signaling. Inhibitors of MAPK signaling, including MEK1/2 inhibitor trametinib, failed to show significant clinical benefit in patients with acquired resistance to vemurafenib. Here, we describe that cell lines with acquired resistance to vemurafenib show reactivation of MAPK signaling and upregulation of cyclin D1 and are sensitive to inhibition of LY2835219, a selective inhibitor of cyclin-dependent kinase (CDK) 4/6. LY2835219 was demonstrated to inhibit growth of melanoma A375 tumor xenografts and delay tumor recurrence in combination with vemurafenib. Furthermore, we developed an in vivo vemurafenib-resistant model by continuous administration of vemurafenib in A375 xenografts. Consistently, we found that MAPK is reactivated and cyclin D1 is elevated in vemurafenib-resistant tumors, as well as in the resistant cell lines derived from these tumors. Importantly, LY2835219 exhibited tumor growth regression in a vemurafenib-resistant model. Mechanistic analysis revealed that LY2835219 induced apoptotic cell death in a concentration-dependent manner in vemurafenib-resistant cells whereas it primarily mediated cell-cycle G1 arrest in the parental cells. Similarly, RNAi-mediated knockdown of cyclin D1 induced significantly higher rate of apoptosis in the resistant cells than in parental cells, suggesting that elevated cyclin D1 activity is important for the survival of vemurafenib-resistant cells. Altogether, we propose that targeting cyclin D1-CDK4/6 signaling by LY2835219 is an effective strategy to overcome MAPK-mediated resistance to B-RAF inhibitors in B-RAF V600E melanoma. ©2014 American Association for Cancer Research.

Morus alba Leaf Lectin (MLL) Sensitizes MCF-7 Cells to Anoikis by Inhibiting Fibronectin Mediated Integrin-FAK Signaling through Ras and Activation of P38 MAPK

PubMed Central

Saranya, Jayaram; Shilpa, Ganesan; Raghu, Kozhiparambil G.; Priya, Sulochana

2017-01-01

Lectins are a unique class of carbohydrate binding proteins/glycoproteins, and many of them possess anticancer properties. They can induce cell cycle arrest and apoptosis, inhibit protein synthesis, telomerase activity and angiogenesis in cancer cells. In the present study, we have demonstrated the effect of Morus alba leaf lectin (MLL) on anoikis induction in MCF-7 cells. Anoikis induction in cancer cells has a significant role in preventing early stage metastasis. MLL treatment in monolayers of MCF-7 cells caused significant detachment of cells in a time and concentration dependent manner. The detached cells failed to re-adhere and grew even to culture plates coated with different matrix proteins. DNA fragmentation, membrane integrity studies, annexin V staining, caspase 9 activation and upregulation of Bax/Bad confirmed that the detached cells underwent apoptosis. Upregulation of matrix metalloproteinase 9 (MMP-9) caused a decrease in fibronectin (FN) production which facilitated the cells to detach by blocking the FN mediated downstream signaling. On treatment with MLL, we have observed downregulation of integrin expression, decreased phosphorylation of focal adhesion kinase (FAK), loss in FAK-integrin interaction and active Ras. MLL treatment downregulated the levels of phosphorylated Akt and PI3K. Also, we have studied the effect of MLL on two stress activated protein kinases p38 MAPK and JNK. p38 MAPK activation was found to be elevated, but there was no change in the level of JNK. Thus our study substantiated the possible antimetastatic effect of MLL by inducing anoikis in MCF-7 cells by activation of caspase 9 and proapoptotic Bax/Bad by blockage of FN mediated integrin/FAK signaling and partly by activation of p38 MAPK. PMID:28223935

Activation of p38 MAPK-regulated Bcl-xL signaling increases survival against zoledronic acid-induced apoptosis in osteoclast precursors.

PubMed

Tai, Ta-Wei; Su, Fong-Chin; Chen, Ching-Yu; Jou, I-Ming; Lin, Chiou-Feng

2014-10-01

The nitrogen-containing bisphosphonate zoledronic acid (ZA) induces apoptosis in osteoclasts and inhibits osteoclast-mediated bone resorption. It is widely used to treat osteoporosis. However, some patients are less responsive to ZA treatment, and the mechanisms of resistance are still unclear. Here, we identified that murine osteoclast precursors may develop resistance to ZA-induced apoptosis. These resistant cells survived the apoptotic effect of ZA following an increase in anti-apoptotic Bcl-xL. Pharmacologically inhibiting Bcl-xL facilitated ZA-induced apoptosis. Treatment with ZA activated p38 MAPK, increasing Bcl-xL expression and cell survival. Nuclear import of β-catenin regulated by p38 MAPK determined Bcl-xL mRNA expression and cell survival in response to ZA. ZA also inactivated glycogen synthase kinase (GSK)-3β, a negative upstream regulator of β-catenin, in a p38 MAPK-mediated manner. Synergistic pharmacological inhibition of p38 MAPK with ZA attenuated receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclast differentiation and facilitated ZA-induced apoptosis. These results demonstrate that elevated Bcl-xL expression mediated by p38 MAPK-regulated GSK-3β/β-catenin signaling is required for cell survival of ZA-induced apoptosis in both osteoclast precursors and osteoclasts. Finally, we demonstrated that inhibiting p38 MAPK-mediated pathway enhanced ZA effect on increasing the bone mineral density of ovariectomized mice. This result suggests that targeting these pathways may represent a potential therapeutic strategy. Copyright © 2014 Elsevier Inc. All rights reserved.

Aclacinomycin A Sensitizes K562 Chronic Myeloid Leukemia Cells to Imatinib through p38MAPK-Mediated Erythroid Differentiation

PubMed Central

Liu, Fu-Hwa; Huang, Yu-Wen; Huang, Huei-Mei

2013-01-01

Expression of oncogenic Bcr-Abl inhibits cell differentiation of hematopoietic stem/progenitor cells in chronic myeloid leukemia (CML). Differentiation therapy is considered to be a new strategy for treating this type of leukemia. Aclacinomycin A (ACM) is an antitumor antibiotic. Previous studies have shown that ACM induced erythroid differentiation of CML cells. In this study, we investigate the effect of ACM on the sensitivity of human CML cell line K562 to Bcr-Abl specific inhibitor imatinib (STI571, Gleevec). We first determined the optimal concentration of ACM for erythroid differentiation but not growth inhibition and apoptosis in K562 cells. Then, pretreatment with this optimal concentration of ACM followed by a minimally toxic concentration of imatinib strongly induced growth inhibition and apoptosis compared to that with simultaneous co-treatment, indicating that ACM-induced erythroid differentiation sensitizes K562 cells to imatinib. Sequential treatment with ACM and imatinib induced Bcr-Abl down-regulation, cytochrome c release into the cytosol, and caspase-3 activation, as well as decreased Mcl-1 and Bcl-xL expressions, but did not affect Fas ligand/Fas death receptor and procaspase-8 expressions. ACM/imatinib sequential treatment-induced apoptosis was suppressed by a caspase-9 inhibitor and a caspase-3 inhibitor, indicating that the caspase cascade is involved in this apoptosis. Furthermore, we demonstrated that ACM induced erythroid differentiation through the p38 mitogen-activated protein kinase (MAPK) pathway. The inhibition of erythroid differentiation by p38MAPK inhibitor SB202190, p38MAPK dominant negative mutant or p38MAPK shRNA knockdown, reduced the ACM/imatinib sequential treatment-mediated growth inhibition and apoptosis. These results suggest that differentiated K562 cells induced by ACM-mediated p38MAPK pathway become more sensitive to imatinib and result in down-regulations of Bcr-Abl and anti-apoptotic proteins, growth inhibition and

Aclacinomycin A sensitizes K562 chronic myeloid leukemia cells to imatinib through p38MAPK-mediated erythroid differentiation.

PubMed

Lee, Yueh-Lun; Chen, Chih-Wei; Liu, Fu-Hwa; Huang, Yu-Wen; Huang, Huei-Mei

2013-01-01

Expression of oncogenic Bcr-Abl inhibits cell differentiation of hematopoietic stem/progenitor cells in chronic myeloid leukemia (CML). Differentiation therapy is considered to be a new strategy for treating this type of leukemia. Aclacinomycin A (ACM) is an antitumor antibiotic. Previous studies have shown that ACM induced erythroid differentiation of CML cells. In this study, we investigate the effect of ACM on the sensitivity of human CML cell line K562 to Bcr-Abl specific inhibitor imatinib (STI571, Gleevec). We first determined the optimal concentration of ACM for erythroid differentiation but not growth inhibition and apoptosis in K562 cells. Then, pretreatment with this optimal concentration of ACM followed by a minimally toxic concentration of imatinib strongly induced growth inhibition and apoptosis compared to that with simultaneous co-treatment, indicating that ACM-induced erythroid differentiation sensitizes K562 cells to imatinib. Sequential treatment with ACM and imatinib induced Bcr-Abl down-regulation, cytochrome c release into the cytosol, and caspase-3 activation, as well as decreased Mcl-1 and Bcl-xL expressions, but did not affect Fas ligand/Fas death receptor and procaspase-8 expressions. ACM/imatinib sequential treatment-induced apoptosis was suppressed by a caspase-9 inhibitor and a caspase-3 inhibitor, indicating that the caspase cascade is involved in this apoptosis. Furthermore, we demonstrated that ACM induced erythroid differentiation through the p38 mitogen-activated protein kinase (MAPK) pathway. The inhibition of erythroid differentiation by p38MAPK inhibitor SB202190, p38MAPK dominant negative mutant or p38MAPK shRNA knockdown, reduced the ACM/imatinib sequential treatment-mediated growth inhibition and apoptosis. These results suggest that differentiated K562 cells induced by ACM-mediated p38MAPK pathway become more sensitive to imatinib and result in down-regulations of Bcr-Abl and anti-apoptotic proteins, growth inhibition and

Suppression of Akt/Foxp3-mediated miR-183 expression blocks Sp1-mediated ADAM17 expression and TNFα-mediated NFκB activation in piceatannol-treated human leukemia U937 cells.

PubMed

Liu, Wen-Hsin; Chang, Long-Sen

2012-09-01

To address the mechanism of piceatannol in inhibiting TNFα-mediated pathway, studies on piceatannol-treated human leukemia U937 cells were conducted. Piceatannol treatment reduced TNFα shedding and NFκB activation and decreased the release of soluble TNFα into the culture medium of U937 cells. Moreover, ADAM17 expression was down-regulated in piceatannol-treated cells. Over-expression of ADAM17 abrogated the ability of piceatannol to suppress TNFα-mediated NFκB activation. Piceatannol-evoked β-TrCP up-regulation promoted Sp1 degradation, thus reducing transcriptional level of ADAM17 gene in U937 cells. Piceatannol treatment induced p38 MAPK phosphorylation but inactivation of Akt and ERK. In contrast to p38 MAPK inhibitor or restoration of ERK activation, transfection of constitutive active Akt abolished the effect of piceatannol on β-TrCP, Sp1 and ADAM17 expression. Piceatannol-elicited down-regulation of miR-183 expression was found to cause β-TrCP up-regulation. Inactivation of Akt resulted in Foxp3 down-regulation and reduced miR-183 expression in piceatannol-treated cells. Knock-down of Foxp3 and chromatin immunoprecipitating revealed that Foxp3 genetically regulated transcription of miR-183 gene. Taken together, our data indicate that suppression of Akt/Foxp3-mediated miR-183 expression blocks Sp1-mediated ADAM17 expression in piceatannol-treated U937 cells. Consequently, piceatannol suppresses TNFα shedding, leading to inhibition of TNFα/NFκB pathway. Copyright © 2012 Elsevier Inc. All rights reserved.

Evolutionary history of mitogen-activated protein kinase (MAPK) genes in Lotus, Medicago, and Phaseolus

PubMed Central

Neupane, Achal; Nepal, Madhav P; Benson, Benjamin V; MacArthur, Kenton J; Piya, Sarbottam

2013-01-01

Mitogen-Activated Protein Kinase (MAPK) genes encode proteins that mediate various signaling pathways associated with biotic and abiotic stress responses in eukaryotes. The MAPK genes form a 3-tier signal transduction cascade between cellular stimuli and physiological responses. Recent identification of soybean MAPKs and availability of genome sequences from other legume species allowed us to identify their MAPK genes. The main objectives of this study were to identify MAPKs in 3 legume species, Lotus japonicus, Medicago truncatula, and Phaseolus vulgaris, and to assess their phylogenetic relationships. We used approaches in comparative genomics for MAPK gene identification and named the newly identified genes following Arabidopsis MAPK nomenclature model. We identified 19, 18, and 15 MAPKs and 7, 4, and 9 MAPKKs in the genome of Lotus japonicus, Medicago truncatula, and Phaseolus vulgaris, respectively. Within clade placement of MAPKs and MAPKKs in the 3 legume species were consistent with those in soybean and Arabidopsis. Among 5 clades of MAPKs, 4 founder clades were consistent to MAPKs of other plant species and orthologs of MAPK genes in the fifth clade-"Clade E" were consistent with those in soybean. Our results also indicated that some gene duplication events might have occurred prior to eudicot-monocot divergence. Highly diversified MAPKs in soybean relative to those in 3 other legume species are attributable to the polyploidization events in soybean. The identification of the MAPK genes in the legume species is important for the legume crop improvement; and evolutionary relationships and functional divergence of these gene members provide insights into plant genome evolution. PMID:24317362

Tangeretin suppresses IL-1beta-induced cyclooxygenase (COX)-2 expression through inhibition of p38 MAPK, JNK, and AKT activation in human lung carcinoma cells.

PubMed

Chen, Kuan-Hung; Weng, Meng-Shih; Lin, Jen-Kun

2007-01-15

Tangeretin (5,6,7,8,4'-pentamethoxyflavone) is a polymethoxylated flavonoid concentrated in the peel of citrus fruits. Recent studies have shown that tangeretin exhibits anti-proliferative, anti-invasive, anti-metastatic, and antioxidant activities. However, the anti-inflammatory properties of tangeretin are unclear. In this study, we examine the effects of tangeretin and its structure-related compound, nobiletin, on the expression of cyclooxygenases-2 (COX-2) in human lung epithelial carcinoma cells, A549, and human non-small cell lung carcinoma cells, H1299. Tangeretin exerts a much better inhibitory activity than nobiletin against IL-1beta-induced production of COX-2 in A549 cells, and it effectively represses the constitutively expressed COX-2 in H1299. RT-PCR was used to investigate the transcriptional inhibition of COX-2 by tangeretin. COX-2 mRNA was rapidly induced by IL-1beta in 3h and markedly suppressed by tangeretin. IL-1beta-induced the activation of ERK, p38 MAPK, JNK, and AKT in A549 cells. COX-2 expression in response to IL-1beta was attenuated by pretreatment with SB203580, SP600125, and LY294002, but not with PD98059, suggesting the involvement of p38 MAPK, JNK, and PI3K in this response. Pretreatment of cells with tangeretin inhibited IL-1beta-induced p38 MAPK, JNK, and AKT phosphorylation and the downstream activation of NF-kappaB. These results may reveal that the tangeretin inhibition of IL-1beta-induced COX-2 expression in A549 cells is, at least in part, mediated through suppression of NF-kappaB transcription factor as well as through suppression of the signaling proteins of p38 MAPK, JNK, and PI3K, but not of ERK.

Vitamin D protects endothelial cells from irradiation-induced senescence and apoptosis by modulating MAPK/SirT1 axis.

PubMed

Marampon, F; Gravina, G L; Festuccia, C; Popov, V M; Colapietro, E A; Sanità, P; Musio, D; De Felice, F; Lenzi, A; Jannini, E A; Di Cesare, E; Tombolini, V

2016-04-01

Radiotherapy toxicity is related to oxidative stress-mediated endothelial dysfunction. Here, we investigated on radioprotective properties of Vitamin D (Vit.D) on human endothelial cells (HUVEC). HUVEC, pre-treated with Vit.D, were exposed to ionizing radiation (IR): ROS production, cellular viability, apoptosis, senescence and western blot for protein detection were performed. The role of MAPKs pathway was investigated by using U0126 (10 μM) MEKs/ERKs-, SB203580 (2.5 μM) p38-inhibitor or by over/expressing MKK6 p38-upstream activator. Vit.D reduced IR-induced ROS production protecting proliferating and quiescent HUVEC from cellular apoptosis or senescence, respectively, by regulating MAPKs pathways. In proliferating HUVEC, Vit.D prevented IR-induced apoptosis by activating ERKs while in quiescent HUVEC counteracted IR-induced senescence by inhibiting the p38-IR-induced activation. MEKs&ERKs inhibition in proliferating or MKK6/mediated p38 activation in quiescent HUVEC, respectively, reverted anti-apoptotic or anti-senescent Vit.D properties. SirT1 protein expression levels were up-regulated by Vit.D. ERKs inhibition blocked Vit.D-induced SirT1 protein up-regulation in proliferating cells. In quiescent HUVEC cells, p38 inhibition counteracted the IR-induced SirT1 protein down-regulation, while MKK6 transfection abrogated the Vit.D positive effects on SirT1 protein levels after irradiation. SirT1 inhibition by sirtinol blocked the Vit.D radioprotective effects. Vit.D protects HUVEC from IR induced/oxidative stress by positively regulating the MAPKs/SirT1 axis.

p38 MAPK Signaling in Pemphigus: Implications for Skin Autoimmunity

PubMed Central

Mavropoulos, Athanasios; Orfanidou, Timoklia; Liaskos, Christos; Smyk, Daniel S.; Spyrou, Vassiliki; Sakkas, Lazaros I.; Rigopoulou, Eirini I.; Bogdanos, Dimitrios P.

2013-01-01

p38 mitogen activated protein kinase (p38 MAPK) signaling plays a major role in the modulation of immune-mediated inflammatory responses and therefore has been linked with several autoimmune diseases. The extent of the involvement of p38 MAPK in the pathogenesis of autoimmune blistering diseases has started to emerge, but whether it pays a critical role is a matter of debate. The activity of p38 MAPK has been studied in great detail during the loss of keratinocyte cell-cell adhesions and the development of pemphigus vulgaris (PV) and pemphigus foliaceus (PF). These diseases are characterised by autoantibodies targeting desmogleins (Dsg). Whether autoantibody-antigen interactions can trigger signaling pathways (such as p38 MAPK) that are tightly linked to the secretion of inflammatory mediators which may perpetuate inflammation and tissue damage in pemphigus remains unclear. Yet, the ability of p38 MAPK inhibitors to block activation of the proapoptotic proteinase caspase-3 suggests that the induction of apoptosis may be a consequence of p38 MAPK activation during acantholysis in PV. This review discusses the current evidence for the role of p38 MAPK in the pathogenesis of pemphigus. We will also present data relating to the targeting of these cascades as a means of therapeutic intervention. PMID:23936634

The JNK-like MAPK KGB-1 of Caenorhabditis elegans promotes reproduction, lifespan, and gene expressions for protein biosynthesis and germline homeostasis but interferes with hyperosmotic stress tolerance.

PubMed

Gerke, Peter; Keshet, Alex; Mertenskötter, Ansgar; Paul, Rüdiger J

2014-01-01

This study focused on the role of the JNK-like MAPK (mitogen-activated protein kinase) KGB-1 (kinase, GLH-binding 1) for osmoprotection and other vital functions. We mapped KGB-1 expression patterns and determined lifespan, reproduction and survival rates as well as changes in body volume, motility, and GPDH (glycerol-3-phosphate dehydrogenase) activity for glycerol production in wildtype (WT), different signaling mutants (including a kgb-1 deletion mutant, kgb-1∆) and RNAi-treated worms under control and hyperosmotic conditions. KGB-1-mediated gene expressions were studied, for instance, by RNA Sequencing, with the resulting transcriptome data analyzed using orthology-based approaches. Surprisingly, mutation/RNAi of kgb-1 and fos-1 (gene for an AP-1, activator protein 1, element) significantly promoted hyperosmotic resistance, even though hyperosmotic GPDH activity was higher in WT than in kgb-1∆. KGB-1 and moderate hyperosmolarity promoted and severe hyperosmolarity repressed kgb-1, fos-1, and jun-1 (gene for another AP-1 element) expression. Transcriptome profiling revealed, for instance, down-regulated genes for protein biosynthesis and up-regulated genes for membrane transporters in kgb-1∆ and up-regulated genes for GPDH-1 or detoxification in WT, with the latter indicating cellular damage and less effective osmoprotection in WT. KGB-1 promotes reproduction and lifespan and fosters gene expressions for AP-1 elements, protein biosynthesis, and balanced gametogenesis, but inhibits expressions for membrane transporters perhaps in order to control energy consumption. Reduced protein biosyntheses and enhanced membrane transports in kgb-1∆ most likely contribute to the high hyperosmotic tolerance of the mutant by easing the burden of the existing chaperone machinery and promoting regulatory volume increases upon hyperosmotic stress.

Herbivory Rapidly Activates MAPK Signaling in Attacked and Unattacked Leaf Regions but Not between Leaves of Nicotiana attenuata[W

PubMed Central

Wu, Jianqiang; Hettenhausen, Christian; Meldau, Stefan; Baldwin, Ian T.

2007-01-01

Mitogen-activated protein kinase (MAPK) signaling plays a central role in transducing extracellular stimuli into intracellular responses, but its role in mediating plant responses to herbivore attack remains largely unexplored. When Manduca sexta larvae attack their host plant, Nicotiana attenuata, the plant's wound response is reconfigured at transcriptional, phytohormonal, and defensive levels due to the introduction of oral secretions (OS) into wounds during feeding. We show that OS dramatically amplify wound-induced MAPK activity and that fatty acid–amino acid conjugates in M. sexta OS are the elicitors. Virus-induced gene silencing of salicylic acid–induced protein kinase (SIPK) and wound-induced protein kinase revealed their importance in mediating wound and OS-elicited hormonal responses and transcriptional regulation of defense-related genes. We found that after applying OS to wounds created in one portion of a leaf, SIPK is activated in both wounded and specific unwounded regions of the leaf but not in phylotactically connected adjacent leaves. We propose that M. sexta attack elicits a mobile signal that travels to nonwounded regions of the attacked leaf where it activates MAPK signaling and, thus, downstream responses; subsequently, a different signal is transported by the vascular system to systemic leaves to initiate defense responses without activating MAPKs in systemic leaves. PMID:17400894

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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.more » 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.« less

Three Fusarium oxysporum mitogen-activated protein kinases (MAPKs) have distinct and complementary roles in stress adaptation and cross-kingdom pathogenicity.

PubMed

Segorbe, David; Di Pietro, Antonio; Pérez-Nadales, Elena; Turrà, David

2017-09-01

Mitogen-activated protein kinase (MAPK) cascades mediate cellular responses to environmental signals. Previous studies in the fungal pathogen Fusarium oxysporum have revealed a crucial role of Fmk1, the MAPK orthologous to Saccharomyces cerevisiae Fus3/Kss1, in vegetative hyphal fusion and plant infection. Here, we genetically dissected the individual and combined contributions of the three MAPKs Fmk1, Mpk1 and Hog1 in the regulation of development, stress response and virulence of F. oxysporum on plant and animal hosts. Mutants lacking Fmk1 or Mpk1 were affected in reactive oxygen species (ROS) homeostasis and impaired in hyphal fusion and aggregation. Loss of Mpk1 also led to increased sensitivity to cell wall and heat stress, which was exacerbated by simultaneous inactivation of Fmk1, suggesting that both MAPKs contribute to cellular adaptation to high temperature, a prerequisite for mammalian pathogens. Deletion of Hog1 caused increased sensitivity to hyperosmotic stress and resulted in partial rescue of the restricted colony growth phenotype of the mpk1Δ mutant. Infection assays on tomato plants and the invertebrate animal host Galleria mellonella revealed distinct and additive contributions of the different MAPKs to virulence. Our results indicate that positive and negative cross-talk between the three MAPK pathways regulates stress adaptation, development and virulence in the cross-kingdom pathogen F. oxysporum. © 2016 BSPP AND JOHN WILEY & SONS LTD.

VGLUT2 Trafficking Is Differentially Regulated by Adaptor Proteins AP-1 and AP-3

PubMed Central

Li, Haiyan; Santos, Magda S.; Park, Chihyung K.; Dobry, Yuriy; Voglmaier, Susan M.

2017-01-01

Release of the major excitatory neurotransmitter glutamate by synaptic vesicle exocytosis depends on glutamate loading into synaptic vesicles by vesicular glutamate transporters (VGLUTs). The two principal isoforms, VGLUT1 and 2, exhibit a complementary pattern of expression in adult brain that broadly distinguishes cortical (VGLUT1) and subcortical (VGLUT2) systems, and correlates with distinct physiological properties in synapses expressing these isoforms. Differential trafficking of VGLUT1 and 2 has been suggested to underlie their functional diversity. Increasing evidence suggests individual synaptic vesicle proteins use specific sorting signals to engage specialized biochemical mechanisms to regulate their recycling. We observed that VGLUT2 recycles differently in response to high frequency stimulation than VGLUT1. Here we further explore the trafficking of VGLUT2 using a pHluorin-based reporter, VGLUT2-pH. VGLUT2-pH exhibits slower rates of both exocytosis and endocytosis than VGLUT1-pH. VGLUT2-pH recycling is slower than VGLUT1-pH in both hippocampal neurons, which endogenously express mostly VGLUT1, and thalamic neurons, which endogenously express mostly VGLUT2, indicating that protein identity, not synaptic vesicle membrane or neuronal cell type, controls sorting. We characterize sorting signals in the C-terminal dileucine-like motif, which plays a crucial role in VGLUT2 trafficking. Disruption of this motif abolishes synaptic targeting of VGLUT2 and essentially eliminates endocytosis of the transporter. Mutational and biochemical analysis demonstrates that clathrin adaptor proteins (APs) interact with VGLUT2 at the dileucine-like motif. VGLUT2 interacts with AP-2, a well-studied adaptor protein for clathrin mediated endocytosis. In addition, VGLUT2 also interacts with the alternate adaptors, AP-1 and AP-3. VGLUT2 relies on distinct recycling mechanisms from VGLUT1. Abrogation of these differences by pharmacological and molecular inhibition reveals that

VGLUT2 Trafficking Is Differentially Regulated by Adaptor Proteins AP-1 and AP-3.

PubMed

Li, Haiyan; Santos, Magda S; Park, Chihyung K; Dobry, Yuriy; Voglmaier, Susan M

2017-01-01

Release of the major excitatory neurotransmitter glutamate by synaptic vesicle exocytosis depends on glutamate loading into synaptic vesicles by vesicular glutamate transporters (VGLUTs). The two principal isoforms, VGLUT1 and 2, exhibit a complementary pattern of expression in adult brain that broadly distinguishes cortical (VGLUT1) and subcortical (VGLUT2) systems, and correlates with distinct physiological properties in synapses expressing these isoforms. Differential trafficking of VGLUT1 and 2 has been suggested to underlie their functional diversity. Increasing evidence suggests individual synaptic vesicle proteins use specific sorting signals to engage specialized biochemical mechanisms to regulate their recycling. We observed that VGLUT2 recycles differently in response to high frequency stimulation than VGLUT1. Here we further explore the trafficking of VGLUT2 using a pHluorin-based reporter, VGLUT2-pH. VGLUT2-pH exhibits slower rates of both exocytosis and endocytosis than VGLUT1-pH. VGLUT2-pH recycling is slower than VGLUT1-pH in both hippocampal neurons, which endogenously express mostly VGLUT1, and thalamic neurons, which endogenously express mostly VGLUT2, indicating that protein identity, not synaptic vesicle membrane or neuronal cell type, controls sorting. We characterize sorting signals in the C-terminal dileucine-like motif, which plays a crucial role in VGLUT2 trafficking. Disruption of this motif abolishes synaptic targeting of VGLUT2 and essentially eliminates endocytosis of the transporter. Mutational and biochemical analysis demonstrates that clathrin adaptor proteins (APs) interact with VGLUT2 at the dileucine-like motif. VGLUT2 interacts with AP-2, a well-studied adaptor protein for clathrin mediated endocytosis. In addition, VGLUT2 also interacts with the alternate adaptors, AP-1 and AP-3. VGLUT2 relies on distinct recycling mechanisms from VGLUT1. Abrogation of these differences by pharmacological and molecular inhibition reveals that

Smad, but not MAPK, pathway mediates the expression of type I collagen in radiation induced fibrosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yano, Hiroyuki; Division of Radioisotope Research, Department of Research Support, Research Promotion Project, Oita University, 1-1 Idaigaoka Hasama-machi, Yufu, Oita 879-5593; Hamanaka, Ryoji

Highlights: Black-Right-Pointing-Pointer We examine how radiation affects the expression level and signal pathway of collagen. Black-Right-Pointing-Pointer TGF-{beta}1 mRNA is elevated earlier than those of collagen genes after irradiation. Black-Right-Pointing-Pointer Smad pathway mediates the expression of collagen in radiation induced fibrosis. Black-Right-Pointing-Pointer MAPK pathways are not affected in the expression of collagen after irradiation. -- Abstract: Radiation induced fibrosis occurs following a therapeutic or accidental radiation exposure in normal tissues. Tissue fibrosis is the excessive accumulation of collagen and other extracellular matrix components. This study investigated how ionizing radiation affects the expression level and signal pathway of type I collagen. Realmore » time RT-RCR showed that both {alpha}1and {alpha}2 chain of type I collagen mRNA were elevated from 48 h after irradiation with 10 Gy in NIH3T3 cells. The relative luciferase activities of both genes and type I collagen marker were elevated at 72 h. TGF-{beta}1 mRNA was elevated earlier than those of type I collagen genes. A Western blot analysis showed the elevation of Smad phosphorylation at 72 h. Conversely, treatment with TGF-{beta} receptor inhibitor inhibited the mRNA and relative luciferase activity of type I collagen. The phosphorylation of Smad was repressed with the inhibitor, and the luciferase activity was cancelled using a mutant construct of Smad binding site of {alpha}2(I) collagen gene. However, the MAPK pathways, p38, ERK1/2 and JNK, were not affected with specific inhibitors or siRNA. The data showed that the Smad pathway mediated the expression of type I collagen in radiation induced fibrosis.« less

Time-dependent activation of MAPK/Erk1/2 and Akt/GSK3 cascades: modulation by agomelatine.

PubMed

Musazzi, Laura; Seguini, Mara; Mallei, Alessandra; Treccani, Giulia; Pelizzari, Mariagrazia; Tornese, Paolo; Racagni, Giorgio; Tardito, Daniela

2014-10-21

The novel antidepressant agomelatine, a melatonergic MT1/MT2 agonist combined with 5-HT2c serotonin antagonist properties, showed antidepressant action in preclinical and clinical studies. There is a general agreement that the therapeutic action of antidepressants needs the activation of slow-onset adaptations in downstream signalling pathways finally regulating neuroplasticity. In the last several years, particular attention was given to cAMP-responsive element binding protein (CREB)-related pathways, since it was shown that chronic antidepressants increase CREB phosphorylation and transcriptional activity, through the activation of calcium/calmodulin-dependent (CaM) and mitogen activated protein kinase cascades (MAPK/Erk1/2). Aim of this work was to analyse possible effects of chronic agomelatine on time-dependent changes of different intracellular signalling pathways in hippocampus and prefrontal/frontal cortex of male rats. To this end, measurements were performed 1 h or 16 h after the last agomelatine or vehicle injection. We have found that in naïve rats chronic agomelatine, contrary to traditional antidepressants, did not increase CREB phosphorylation, but modulates the time-dependent regulation of MAPK/Erk1/2 and Akt/glycogen synthase kinase-3 (GSK-3) pathways. Our results suggest that the intracellular molecular mechanisms modulated by chronic agomelatine may be partly different from those of traditional antidepressants and involve the time-dependent regulation of MAPK/Erk1/2 and Akt/GSK-3 signalling pathways. This could exert a role in the antidepressant efficacy of the drug.

Unexpected Heterodivalent Recruitment of NOS1AP to nNOS Reveals Multiple Sites for Pharmacological Intervention in Neuronal Disease Models.

PubMed

Li, Li-Li; Melero-Fernandez de Mera, Raquel M; Chen, Jia; Ba, Wei; Kasri, Nael Nadif; Zhang, Mingjie; Courtney, Michael J

2015-05-13

The protein NOS1AP/CAPON mediates signaling from a protein complex of NMDA receptor, PSD95 and nNOS. The only stroke trial for neuroprotectants that showed benefit to patients targeted this ternary complex. NOS1AP/nNOS interaction regulates small GTPases, iron transport, p38MAPK-linked excitotoxicity, and anxiety. Moreover, the nos1ap gene is linked to disorders from schizophrenia, post-traumatic stress disorder, and autism to cardiovascular disorders and breast cancer. Understanding protein interactions required for NOS1AP function, therefore, has broad implications for numerous diseases. Here we show that the interaction of NOS1AP with nNOS differs radically from the classical PDZ docking assumed to be responsible. The NOS1AP PDZ motif does not bind nNOS as measured by multiple methods. In contrast, full-length NOS1AP forms an unusually stable interaction with nNOS. We mapped the discrepancy between full-length and C-terminal PDZ motif to a novel internal region we call the ExF motif. The C-terminal PDZ motif, although neither sufficient nor necessary for binding, nevertheless promotes the stability of the complex. It therefore potentially affects signal transduction and suggests that functional interaction of nNOS with NOS1AP might be targetable at two distinct sites. We demonstrate that excitotoxic pathways can be regulated, in cortical neuron and organotypic hippocampal slice cultures from rat, either by the previously described PDZ ligand TAT-GESV or by the ExF motif-bearing region of NOS1AP, even when lacking the critical PDZ residues as long as the ExF motif is intact and not mutated. This previously unrecognized heterodivalent interaction of nNOS with NOS1AP may therefore provide distinct opportunities for pharmacological intervention in NOS1AP-dependent signaling and excitotoxicity. Copyright © 2015 the authors 0270-6474/15/357349-16$15.00/0.

The FGL2/fibroleukin prothrombinase is involved in alveolar macrophage activation in COPD through the MAPK pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yanling; Xu, Sanpeng; Xiao, Fei

2010-05-28

Fibrinogen-like protein 2 (FGL2)/fibroleukin has been reported to play a vital role in the pathogenesis of some critical inflammatory diseases by possessing immunomodulatory activity through the mediation of 'immune coagulation' and the regulation of maturation and proliferation of immune cells. We observed upregulated FGL2 expression in alveolar macrophages from peripheral lungs of chronic obstructive pulmonary disease (COPD) patients and found a correlation between FGL2 expression and increased macrophage activation markers (CD11b and CD14). The role of FGL2 in the activation of macrophages was confirmed by the detection of significantly decreased macrophage activation marker (CD11b, CD11c, and CD71) expression as wellmore » as the inhibition of cell migration and inflammatory cytokine (IL-8 and MMP-9) production in an LPS-induced FGL2 knockdown human monocytic leukemia cell line (THP-1). Increased FGL2 expression co-localized with upregulated phosphorylated p38 mitogen-activated protein kinase (p38-MAPK) in the lung tissues from COPD patients. Moreover, FGL2 knockdown in THP-1 cells significantly downregulated LPS-induced phosphorylation of p38-MAPK while upregulating phosphorylation of c-Jun N-terminal kinase (JNK). Thus, we demonstrate that FGL2 plays an important role in macrophage activation in the lungs of COPD patients through MAPK pathway modulation.« less

Protective Effect of Tropisetron on Rodent Hepatic Injury after Trauma-Hemorrhagic Shock through P38 MAPK-Dependent Hemeoxygenase-1 Expression

PubMed Central

Hwang, Tsong-Long; Tsai, Yung-Fong

2012-01-01

Tropisetron can decrease inflammatory cell responses and alleviate organ damage caused by trauma-hemorrhage, but the mechanism of these effects remains unknown. The p38 mitogen-activated protein kinase/hemeoxygenase-1 (p38 MAPK/HO-1) pathway exerts anti-inflammatory effects on different tissues. The aim of this study was to investigate whether p38 MAPK/HO-1 plays any role in the tropisetron-mediated attenuation of hepatic injury after trauma-hemorrhage. Male Sprague-Dawley rats underwent trauma-hemorrhage (mean blood pressure maintained at approximately 35–40 mmHg for 90 min), followed by fluid resuscitation. During resuscitation, several treatment regimens were administered: four doses of tropisetron alone (0.1, 0.3, 1, 3 mg/kg body weight), or a single dose of tropisetron (1 mg/kg body weight) with and without a p38 MAPK inhibitor (SB-203580, 2 mg/kg body weight) or HO antagonist (chromium-mesoporphyrin, 2.5 mg/kg body weight). Various parameters were measured, and the animals were sacrificed at 24 h post-resuscitation. The results showed that trauma-hemorrhage increased the following parameters: plasma concentrations of aspartate (AST) and alanine aminotransferases (ALT), hepatic myeloperoxidase (MPO) activity, and levels of cytokine-induced neutrophil chemoattractant-1 and -3 (CINC-1 and CINC-3), intercellular adhesion molecule-1 (ICAM-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and macrophage inflammatory protein-1α (MIP-1α). These parameters were significantly improved in the tropisetron-treated rats subjected to trauma-hemorrhage. Tropisetron treatment also increased hepatic p38 MAPK and HO-1 expression compared with vehicle-treated trauma-hemorrhaged rats. Co-administration of SB-203580 or chromium-mesoporphyrin with tropisetron abolished the tropisetron-induced beneficial effects on the above parameters and hepatic injury. These results suggest that the protective effect of tropisetron administration on alleviation of hepatic injury

Protective effect of tropisetron on rodent hepatic injury after trauma-hemorrhagic shock through P38 MAPK-dependent hemeoxygenase-1 expression.

PubMed

Liu, Fu-Chao; Yu, Huang-Ping; Hwang, Tsong-Long; Tsai, Yung-Fong

2012-01-01

Tropisetron can decrease inflammatory cell responses and alleviate organ damage caused by trauma-hemorrhage, but the mechanism of these effects remains unknown. The p38 mitogen-activated protein kinase/hemeoxygenase-1 (p38 MAPK/HO-1) pathway exerts anti-inflammatory effects on different tissues. The aim of this study was to investigate whether p38 MAPK/HO-1 plays any role in the tropisetron-mediated attenuation of hepatic injury after trauma-hemorrhage. Male Sprague-Dawley rats underwent trauma-hemorrhage (mean blood pressure maintained at approximately 35-40 mmHg for 90 min), followed by fluid resuscitation. During resuscitation, several treatment regimens were administered: four doses of tropisetron alone (0.1, 0.3, 1, 3 mg/kg body weight), or a single dose of tropisetron (1 mg/kg body weight) with and without a p38 MAPK inhibitor (SB-203580, 2 mg/kg body weight) or HO antagonist (chromium-mesoporphyrin, 2.5 mg/kg body weight). Various parameters were measured, and the animals were sacrificed at 24 h post-resuscitation. The results showed that trauma-hemorrhage increased the following parameters: plasma concentrations of aspartate (AST) and alanine aminotransferases (ALT), hepatic myeloperoxidase (MPO) activity, and levels of cytokine-induced neutrophil chemoattractant-1 and -3 (CINC-1 and CINC-3), intercellular adhesion molecule-1 (ICAM-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and macrophage inflammatory protein-1α (MIP-1α). These parameters were significantly improved in the tropisetron-treated rats subjected to trauma-hemorrhage. Tropisetron treatment also increased hepatic p38 MAPK and HO-1 expression compared with vehicle-treated trauma-hemorrhaged rats. Co-administration of SB-203580 or chromium-mesoporphyrin with tropisetron abolished the tropisetron-induced beneficial effects on the above parameters and hepatic injury. These results suggest that the protective effect of tropisetron administration on alleviation of hepatic injury

(-)-7(S)-hydroxymatairesinol protects against tumor necrosis factor-α-mediated inflammation response in endothelial cells by blocking the MAPK/NF-κB and activating Nrf2/HO-1.

PubMed

Yang, Di; Xiao, Chen-Xi; Su, Zheng-Hua; Huang, Meng-Wei; Qin, Ming; Wu, Wei-Jun; Jia, Wan-Wan; Zhu, Yi-Zhun; Hu, Jin-Feng; Liu, Xin-Hua

2017-08-15

Endothelial inflammation is an increasingly prevalent condition in the pathogenesis of many cardiovascular diseases. (-)-7(S)-hydroxymatairesinol (7-HMR), a naturally occurring plant lignan, possesses both antioxidant and anti-cancer properties and therefore would be a good strategy to suppress tumor necrosis factor-α (TNF-α)-mediated inflammation in vascular endothelial cells (VECs). The objective of this study is to evaluate for its anti-inflammatory effect on TNF-α-stimulated VECs and underling mechanisms. The effect of the 7-HMR on suppression of TNF-α-induced inflammation mediators in VECs were determined by qRT-PCR and Western blot. MAPKs and phosphorylation of Akt, HO-1 and NF-κB p65 were examined using Western blot. Nuclear localisation of NF-κB was also examined using Western blot and immunofluorescence. Here we found that 7-HMR could suppress TNF-α-induced inflammatory mediators, such as vascularcelladhesion molecule-1, interleukin-6 and inducible nitric oxide synthase expression both in mRNA and protein levels, and concentration-dependently attenuated reactive oxidase species generation. We further identified that 7-HMR remarkably induced superoxide dismutase and heme oxygenase-1 expression associated with degradation of Kelch-like ECH-associated protein 1 (keap1) and up-regulated nuclear factor erythroid 2-related factor 2 (Nrf2). In addition, 7-HMR time- and concentration-dependently attenuated TNF-α-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK) and Akt, but not p38, or c-Jun N-terminal kinase 1/2. Moreover, 7-HMR significantly suppressed TNF-α-mediated nuclear factor-κB (NF-κB) activation by inhibiting phosphorylation and nuclear translocation of NF-κB p65. Our results demonstrated that 7-HMR inhibited TNF-α-stimulated endothelial inflammation, at least in part, through inhibition of NF-κB activation and upregulation of Nrf2-antioxidant response element signaling pathway, suggesting 7-HMR might be used as a

Heat stress prevents lipopolysaccharide-induced apoptosis in pulmonary microvascular endothelial cells by blocking calpain/p38 MAPK signalling.

PubMed

Liu, Zhi-Feng; Zheng, Dong; Fan, Guo-Chang; Peng, Tianqing; Su, Lei

2016-08-01

Pulmonary microvascular endothelial cells (PMECs) injury including apoptosis plays an important role in the pathogenesis of acute lung injury during sepsis. Our recent study has demonstrated that calpain activation contributes to apoptosis in PMECs under septic conditions. This study investigated how calpain activation mediated apoptosis and whether heat stress regulated calpain activation in lipopolysaccharides (LPS)-stimulated PMECs. In cultured mouse primary PMECs, incubation with LPS (1 μg/ml, 24 h) increased active caspase-3 fragments and DNA fragmentation, indicative of apoptosis. These effects of LPS were abrogated by pre-treatment with heat stress (43 °C for 2 h). LPS also induced calpain activation and increased phosphorylation of p38 MAPK. Inhibition of calpain and p38 MAPK prevented apoptosis induced by LPS. Furthermore, inhibition of calpain blocked p38 MAPK phosphorylation in LPS-stimulated PMECs. Notably, heat stress decreased the protein levels of calpain-1/2 and calpain activities, and blocked p38 MAPK phosphorylation in response to LPS. Additionally, forced up-regulation of calpain-1 or calpain-2 sufficiently induced p38 MAPK phosphorylation and apoptosis in PMECs, both of which were inhibited by heat stress. In conclusion, heat stress prevents LPS-induced apoptosis in PMECs. This effect of heat stress is associated with down-regulation of calpain expression and activation, and subsequent blockage of p38 MAPK activation in response to LPS. Thus, blocking calpain/p38 MAPK pathway may be a novel mechanism underlying heat stress-mediated inhibition of apoptosis in LPS-stimulated endothelial cells.

Heat stress prevents lipopolysaccharide-induced apoptosis in pulmonary microvascular endothelial cells by blocking calpain/p38 MAPK signalling

PubMed Central

Liu, Zhi-feng; Zheng, Dong; Fan, Guo-chang; Peng, Tianqing; Su, Lei

2016-01-01

Pulmonary microvascular endothelial cells (PMECs) injury including apoptosis plays an important role in the pathogenesis of acute lung injury during sepsis. Our recent study has demonstrated that calpain activation contributes to apoptosis in PMECs under septic conditions. This study investigated how calpain activation mediated apoptosis and whether heat stress regulated calpain activation in lipopolysaccharides (LPS)-stimulated PMECs. In cultured mouse primary PMECs, incubation with LPS (1 µg/ml, 24 h) increased active caspase-3 fragments and DNA fragmentation, indicative of apoptosis. These effects of LPS were abrogated by pre-treatment with heat stress (43 °C for 2 h). LPS also induced calpain activation and increased phosphorylation of p38 MAPK. Inhibition of calpain and p38 MAPK prevented apoptosis induced by LPS. Furthermore, inhibition of calpain blocked p38 MAPK phosphorylation in LPS-stimulated PMECs. Notably, heat stress decreased the protein levels of calpain-1/2 and calpain activities, and blocked p38 MAPK phosphorylation in response to LPS. Additionally, forced up-regulation of calpain-1 or calpain-2 sufficiently induced p38 MAPK phosphorylation and apoptosis in PMECs, both of which were inhibited by heat stress. In conclusion, heat stress prevents LPS-induced apoptosis in PMECs. This effect of heat stress is associated with down-regulation of calpain expression and activation, and subsequent blockage of p38 MAPK activation in response to LPS. Thus, blocking calpain/p38 MAPK pathway may be a novel mechanism underlying heat stress-mediated inhibition of apoptosis in LPS-stimulated endothelial cells. PMID:27325431

PKCalpha-mediated ERK, JNK and p38 activation regulates the myogenic program in human rhabdomyosarcoma cells.

PubMed

Mauro, Annunziata; Ciccarelli, Carmela; De Cesaris, Paola; Scoglio, Arianna; Bouché, Marina; Molinaro, Mario; Aquino, Angelo; Zani, Bianca Maria

2002-09-15

We have previously suggested that PKCalpha has a role in 12-O-Tetradecanoylphorbol-13-acetate (TPA)-mediated growth arrest and myogenic differentiation in human embryonal rhabdomyosarcoma cells (RD). Here, by monitoring the signalling pathways triggered by TPA, we demonstrate that PKCalpha mediates these effects by inducing transient activation of c-Jun N-terminal protein kinases (JNKs) and sustained activation of both p38 kinase and extracellular signal-regulated kinases (ERKs) (all referred to as MAPKs). Activation of MAPKs following ectopic expression of constitutively active PKCalpha, but not its dominant-negative form, is also demonstrated. We investigated the selective contribution of MAPKs to growth arrest and myogenic differentiation by monitoring the activation of MAPK pathways, as well as by dissecting MAPK pathways using MEK1/2 inhibitor (UO126), p38 inhibitor (SB203580) and JNK and p38 agonist (anisomycin) treatments. Growth-arresting signals are triggered either by transient and sustained JNK activation (by TPA and anisomycin, respectively) or by preventing both ERK and JNK activation (UO126) and are maintained, rather than induced, by p38. We therefore suggest a key role for JNK in controlling ERK-mediated mitogenic activity. Notably, sarcomeric myosin expression is induced by both TPA and UO126 but is abrogated by the p38 inhibitor. This finding indicates a pivotal role for p38 in controlling the myogenic program. Anisomycin persistently activates p38 and JNKs but prevents myosin expression induced by TPA. In accordance with this negative role, reactivation of JNKs by anisomycin, in UO126-pre-treated cells, also prevents myosin expression. This indicates that, unlike the transient JNK activation that occurs in the TPA-mediated myogenic process, long-lasting JNK activation supports the growth-arrest state but antagonises p38-mediated myosin expression. Lastly, our results with the MEK inhibitor suggest a key role of the ERK pathway in regulating

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

PubMed

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

2002-09-12

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

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

PubMed

Mahata, Sutapa; Bharti, Alok C; Shukla, Shirish; Tyagi, Abhishek; Husain, Syed A; Das, Bhudev C

2011-04-15

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

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

PubMed Central

2011-01-01

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

A herbal formula comprising Rosae Multiflorae Fructus and Lonicerae Japonicae Flos inhibits the production of inflammatory mediators and the IRAK-1/TAK1 and TBK1/IRF3 pathways in RAW 264.7 and THP-1 cells.

PubMed

Cheng, Brian Chi Yan; Yu, Hua; Su, Tao; Fu, Xiu-Qiong; Guo, Hui; Li, Ting; Cao, Hui-Hui; Tse, Anfernee Kai-Wing; Kwan, Hiu-Yee; Yu, Zhi-Ling

2015-11-04

As documented in the Chinese Materia Medica Grand Dictionary (), a herbal formula (RL) consisting of Rosae Multiflorae Fructus (multiflora rose hips) and Lonicerae Japonicae Flos (Japanese honeysuckle flowers) has traditionally been used in treating inflammatory disorders. RL was previously reported to inhibit the expression of various inflammatory mediators regulated by NF-κB and MAPKs that are components of the TLR4 signalling pathways. This study aims to provide further justification for clinical application of RL in treating inflammatory disorders by further delineating the involvement of the TLR4 signalling cascades in the effects of RL on inflammatory mediators. RL consisting of Rosae Multiflorae Fructus and Lonicerae Japonicae Flos (in 5:3 ratio) was extracted using absolute ethanol. We investigated the effect of RL on the production of cytokines and chemokines that are regulated by three key transcription factors of the TLR4 signalling pathways AP-1, NF-κB and IRF3 in LPS-stimulated RAW264.7 cells using the multiplex biometric immunoassay. Phosphorylation of AP-1, NF-κB, IRF3, IκB-α, IKKα/β, Akt, TAK1, TBK1, IRAK-1 and IRAK-4 were examined in LPS-stimulated RAW264.7 cells and THP-1 cells using Western blotting. Nuclear localizations of AP-1, NF-κB and IRF3 were also examined using Western blotting. RL reduced the secretion of various pro-inflammatory cytokines and chemokines regulated by transcription factors AP-1, NF-κB and IRF3. Phosphorylation and nuclear protein levels of these transcription factors were decreased by RL treatment. Moreover, RL inhibited the activation/phosphorylation of IκB-α, IKKα/β, TAK1, TBK1 and IRAK-1. Suppression of the IRAK-1/TAK1 and TBK1/IRF3 signalling pathways was associated with the effect of RL on inflammatory mediators in LPS-stimulated RAW264.7 and THP-1 cells. This provides further pharmacological basis for the clinical application of RL in the treatment of inflammatory disorders. Copyright © 2015 Elsevier

Effects of Cyclic Mechanical Stretch on the Proliferation of L6 Myoblasts and Its Mechanisms: PI3K/Akt and MAPK Signal Pathways Regulated by IGF-1 Receptor.

PubMed

Fu, Shaoting; Yin, Lijun; Lin, Xiaojing; Lu, Jianqiang; Wang, Xiaohui

2018-06-02

Myoblast proliferation is crucial to skeletal muscle hypertrophy and regeneration. Our previous study indicated that mechanical stretch altered the proliferation of C2C12 myoblasts, associated with insulin growth factor 1 (IGF-1)-mediated phosphoinositide 3-kinase (PI3K)/Akt (also known as protein kinase B) and mitogen-activated protein kinase (MAPK) pathways through IGF-1 receptor (IGF-1R). The purpose of this study was to explore the same stretches on the proliferation of L6 myoblasts and its association with IGF-1-regulated PI3K/Akt and MAPK activations. L6 myoblasts were divided into three groups: control, 15% stretch, and 20% stretch. Stretches were achieved using FlexCell Strain Unit. Cell proliferation and IGF-1 concentration were detected by CCK8 and ELISA, respectively. IGF-1R expression, and expressions and activities of PI3K, Akt, and MAPKs (including extracellular signal-regulated kinases 1 and 2 (ERK1/2) and p38) were determined by Western blot. We found that 15% stretch promoted, while 20% stretch inhibited L6 myoblast proliferation. A 15% stretch increased IGF-1R level, although had no effect on IGF-1 secretion of L6 myoblasts, and PI3K/Akt and ERK1/2 (not p38) inhibitors attenuated 15% stretch-induced pro-proliferation. Exogenous IGF-1 reversed 20% stretch-induced anti-proliferation, accompanied with increases in IGF-1R level as well as PI3K/Akt and MAPK (ERK1/2 and p38) activations. In conclusion, stretch regulated L6 myoblasts proliferation, which may be mediated by the changes in PI3K/Akt and MAPK activations regulated by IGF-1R, despite no detectable IGF-1 from stretched L6 myoblasts.

THE AP-2 CLATHRIN ADAPTOR MEDIATES ENDOCYTOSIS OF AN INHIBITORY KILLER CELL Ig-LIKE RECEPTOR (KIR) IN HUMAN NK CELLS1

PubMed Central

Purdy, Amanda K.; Alvarez-Arias, Diana A.; Oshinsky, Jennifer; James, Ashley M.; Serebriiskii, Ilya; Campbell, Kerry S.

2014-01-01

Stable surface expression of human inhibitory killer cell immunoglobulin-like receptors (KIR) is critical for controlling NK cell function and maintaining NK cell tolerance toward normal MHC-I+ cells. Our recent experiments, however, have found that antibody-bound KIR3DL1 (3DL1) readily leaves the cell surface and undergoes endocytosis to early/recycling endosomes and subsequently to late endosomes. We found that 3DL1 internalization is at least partially mediated by an interaction between the μ2 subunit of the AP-2 clathrin adaptor complex and ITIM tyrosine residues in the cytoplasmic domain of 3DL1. Disruption of the 3DL1/μ2 interaction, either by mutation of the ITIM tyrosines in 3DL1 or mutation of μ2, significantly diminished endocytosis and increased surface expression of 3DL1 in human primary NK cells and cell lines. Furthermore, we found that the 3DL1/AP-2 interaction is diminished upon antibody engagement with the receptor, as compared to untreated cells. Thus, we have identified AP-2-mediated endocytosis as a mechanism regulating the surface levels of inhibitory KIR though their ITIM domains. Based upon our results, we propose a model in which non-engaged KIR are internalized by this mechanism, whereas engagement with MHC-I ligand would diminish AP-2 binding, thereby prolonging stable receptor surface expression and promoting inhibitory function. Furthermore, this ITIM-mediated mechanism may similarly regulate the surface expression of other inhibitory immune receptors. PMID:25238755

High-Mobility Group Box 1 Mediates Fibroblast Activity via RAGE-MAPK and NF-κB Signaling in Keloid Scar Formation.

PubMed

Kim, Jihee; Park, Jong-Chul; Lee, Mi Hee; Yang, Chae Eun; Lee, Ju Hee; Lee, Won Jai

2017-12-28

Emerging studies have revealed the involvement of high-mobility group box 1 (HMGB1) in systemic fibrotic diseases, yet its role in the cutaneous scarring process has not yet been investigated. We hypothesized that HMGB1 may promote fibroblast activity to cause abnormal cutaneous scarring. In vitro wound healing assay with normal and keloid fibroblasts demonstrated that HMGB1 administration promoted the migration of both fibroblasts with increased speed and a greater traveling distance. Treatment of the HMGB1 inhibitor glycyrrhizic acid (GA) showed an opposing effect on both activities. To analyze the downstream mechanism, the protein levels of extracellular signal-regulated kinase (ERK) 1/2, protein kinase B (AKT), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) were measured by western blot analysis. HMGB1 increased the expression levels of ERK1/2, AKT, and NF-κB compared to the control, which was suppressed by GA. HMGB1 promoted both normal and keloid fibroblasts migration to a degree equivalent to that achieved with TGF-β. We concluded that HMGB1 activates fibroblasts via the receptor for advanced glycation end product (RAGE)-mitogen-activated protein kinases (MAPK) and NF-κB interaction signaling pathways. Further knowledge of the relationship of HMGB1 with skin fibrosis may lead to a promising clinical approach to manage abnormal scarring.

Neurotrophin Promotes Neurite Outgrowth by Inhibiting Rif GTPase Activation Downstream of MAPKs and PI3K Signaling.

PubMed

Tian, Xiaoxia; Yan, Huijuan; Li, Jiayi; Wu, Shuang; Wang, Junyu; Fan, Lifei

2017-01-13

Members of the well-known semaphorin family of proteins can induce both repulsive and attractive signaling in neural network formation and their cytoskeletal effects are mediated in part by small guanosine 5'-triphosphatase (GTPases). The aim of this study was to investigate the cellular role of Rif GTPase in the neurotrophin-induced neurite outgrowth. By using PC12 cells which are known to cease dividing and begin to show neurite outgrowth responding to nerve growth factor (NGF), we found that semaphorin 6A was as effective as nerve growth factor at stimulating neurite outgrowth in PC12 cells, and that its neurotrophic effect was transmitted through signaling by mitogen-activated protein kinases (MAPKs) and phosphatidylinositol-3-kinase (PI3K). We further found that neurotrophin-induced neurite formation in PC12 cells could be partially mediated by inhibition of Rif GTPase activity downstream of MAPKs and PI3K signaling. In conclusion, we newly identified Rif as a regulator of the cytoskeletal rearrangement mediated by semaphorins.

Ca2+ -stimulated adenylyl cyclases regulate ERK-dependent activation of MSK1 during fear conditioning.

PubMed

Sindreu, Carlos Balet; Scheiner, Zachary S; Storm, Daniel R

2007-01-04

The cAMP and ERK/MAP kinase (MAPK) signal transduction pathways are critical for hippocampus-dependent memory, a process that depends on CREB-mediated transcription. However, the extent of crosstalk between these pathways and the downstream CREB kinase activated during memory formation has not been elucidated. Here we report that PKA, MAPK, and MSK1, a CREB kinase, are coactivated in a subset of hippocampal CA1 pyramidal neurons following contextual fear conditioning. Activation of PKA, MAPK, MSK1, and CREB is absolutely dependent on Ca(2+)-stimulated adenylyl cyclase activity. We conclude that adenylyl cyclase activity supports the activation of MAPK, and that MSK1 is the major CREB kinase activated during training for contextual memory.

RhoA-ROCK and p38MAPK-MSK1 mediate vitamin D effects on gene expression, phenotype, and Wnt pathway in colon cancer cells.

PubMed

Ordóñez-Morán, Paloma; Larriba, María Jesús; Pálmer, Héctor G; Valero, Ruth A; Barbáchano, Antonio; Duñach, Mireia; de Herreros, Antonio García; Villalobos, Carlos; Berciano, María Teresa; Lafarga, Miguel; Muñoz, Alberto

2008-11-17

The active vitamin D metabolite 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) inhibits proliferation and promotes differentiation of colon cancer cells through the activation of vitamin D receptor (VDR), a transcription factor of the nuclear receptor superfamily. Additionally, 1,25(OH)(2)D(3) has several nongenomic effects of uncertain relevance. We show that 1,25(OH)(2)D(3) induces a transcription-independent Ca(2+) influx and activation of RhoA-Rho-associated coiled kinase (ROCK). This requires VDR and is followed by activation of the p38 mitogen-activated protein kinase (p38MAPK) and mitogen- and stress-activated kinase 1 (MSK1). As shown by the use of chemical inhibitors, dominant-negative mutants and small interfering RNA, RhoA-ROCK, and p38MAPK-MSK1 activation is necessary for the induction of CDH1/E-cadherin, CYP24, and other genes and of an adhesive phenotype by 1,25(OH)(2)D(3). RhoA-ROCK and MSK1 are also required for the inhibition of Wnt-beta-catenin pathway and cell proliferation. Thus, the action of 1,25(OH)(2)D(3) on colon carcinoma cells depends on the dual action of VDR as a transcription factor and a nongenomic activator of RhoA-ROCK and p38MAPK-MSK1.

Early Activation of MAPK and Apoptosis in Nutritive Embryos of Calyptraeid Gastropods.

PubMed

Lesoway, Maryna P; Collin, Rachel; Abouheif, Ehab

2017-07-01

Investigation of alternative phenotypes, different morphologies produced by a single genome, has contributed novel insights into development and evolution. Yet, the mechanisms underlying developmental switch points between alternative phenotypes remain poorly understood. The calyptraeid snails Crepidula navicella and Calyptraea lichen produce two phenotypes: viable and nutritive embryos, where nutritive embryos arrest their development after gastrulation and are ingested by their viable siblings as a form of intracapsular nutrition. Here, we investigate the activity of mitogen-activated protein kinase (MAPK, ERK1/2) and apoptosis during early cleavage. MAPK and apoptosis, found in a previous transcriptomic study, are known to be involved in organization of other spiralian embryos and nutritive embryo development, respectively. In the model Crepidula fornicata, MAPK activation begins at the 16-cell stage. In contrast, we discovered in C. navicella and C. lichen that many embryos begin MAPK activation at the one-cell stage. A subset of embryos shows a similar pattern of MAPK activation to C. fornicata at later stages. In all stages where MAPK is detected, the activation pattern is highly variable, frequently occurring in all quadrants or in multiple tiers of cells. We also detected apoptosis in cleaving embryos, while C. fornicata and Crepidula lessoni, which do not produce nutritive embryos, show no signs of apoptosis during cleavage. Our results show that MAPK and apoptosis are expressed during early development in species with nutritive embryos, and raises the possibility that these processes may play a role and even interact with one another in producing the nutritive embryo phenotype. © 2017 Wiley Periodicals, Inc.

p38 Mitogen Activated Protein Kinase (MAPK): A New Therapeutic Target for Reducing the Risk of Adverse Pregnancy Outcomes

PubMed Central

Menon, Ramkumar; Papaconstantinou, John

2016-01-01

Introduction Spontaneous preterm birth (PTB) and preterm premature rupture of the membranes (pPROM) remain as a major clinical and therapeutic problem for intervention and management. Current strategies, based on our knowledge of pathways of preterm labor, have only been effective, in part, due to major gaps in our existing knowledge of risks and risk specific pathways. Areas covered Recent literature has identified physiologic aging of fetal tissues as a potential mechanistic feature of normal parturition. This process is affected by telomere dependent and p38 mitogen activated protein kinase (MAPK) induced senescence activation. Pregnancy associated risk factors can cause pathologic activation of this pathway that can cause oxidative stress induced p38 MAPK activation leading to senescence and premature aging of fetal tissues. Premature aging is associated with sterile inflammation capable of triggering preterm labor or preterm premature rupture of membranes. Preterm activation of p38MAPK can be considered as a key contributor to adverse pregnancies. Expert Opinion This review considers p38MAPK activation as a potential target for therapeutic interventions to prevent adverse pregnancy outcomes mediated by stress factors. In this review, we propose multiple strategies to prevent p38MAPK activation and its functional effects. PMID:27459026

Ribes nigrum L. Prevents UVB-mediated Photoaging in Human Dermal Fibroblasts: Potential Antioxidant and Antiinflammatory Activity.

PubMed

Li, Lu; Hwang, Eunson; Ngo, Hien T T; Seo, Seul A; Lin, Pei; Gao, Wei; Liu, Ying; Yi, Tae-Hoo

2018-05-16

Black currants (Ribes nigrum L, RN) are known as a "super fruit" to possess for their many potential health benefits such as the alleviation of oxidative stress-related disorders. However, little skin photoaging-related research has been done on the use of this agent. In the present study, we investigated the protective effects of RN in UVB-irradiated human dermal fibroblasts (NHDFs). RN treatment in UVB-irradiated skin models alleviated UVB-mediated photoaging through several mechanisms: Treatment with RN downregulated MAPK-related signaling models, such as those of activation protein 1 (AP-1) and nuclear factor kappa B (NF-κB). In addition, phase II gene heme oxygenase-1 (HO-1) was modulated by the increase in nuclear factor erythroid 2-related factor 2 (Nrf2) in the nuclear, and finally, transforming growth factor TGF-β was upregulated in vitro. Further study indicated that UVB-induced production of MMP-1 and IL-6 could be inhibited by PD 98059 (an inhibitor of ERK) and SP600125 (an inhibitor of JNK). Thus, RN improved the expression of type I procollagen and inhibited UVB-induced MMP-1 and IL-6 secretion through inactivating MAPK cascades. Therefore, RN is a suitable target for further investigation as an antiphotoaging agent and may have applications in the skincare industry. © 2018 The American Society of Photobiology.

Up-regulation of IL-23 expression in human dental pulp fibroblasts by IL-17 via activation of the NF-κB and MAPK pathways.

PubMed

Wei, L; Liu, M; Xiong, H; Peng, B

2017-11-06

To investigate the effects of the pro-inflammatory and Th17-polarizing mediator IL-17 on HDPFs-mediated IL-23 production and the molecular mechanism involved. Interleukin (IL)-17R expression was determined by semi-quantitative reverse transcriptase-polymerase chain reaction and Western blot in cultured human dental pulp fibroblasts (HDPFs). Quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay were used to determine IL-23 mRNA and protein levels in IL-17-stimulated HDPFs, respectively. The nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) signalling pathways that mediate the IL-17-stimulated production of IL-23 was investigated using Western blot and specific signalling inhibitor analyses. Statistical analyses were performed using Kruskal-Wallis tests followed by the Mann-Whitney U-test. Statistical significance was considered when the P value < 0.05. Primary HDPFs steadily expressed IL-17R mRNA and surface-bound protein. IL-17 stimulated the expression of IL-23 mRNA and protein in cultured human dental pulp fibroblasts, which was attenuated by IL-17 or IL-17R neutralizing antibodies. In accordance with the enhanced expression of IL-23, IL-17 stimulation resulted in rapid activation of p38 MAPK, extracellular signal-regulated kinase (ERK) 1/2, c-Jun-N-terminal kinase (JNK) and NF-κB in HDPFs. Inhibitors of p38 MAPK, ERK 1/2 or NF-κB significantly suppressed, whereas blocking JNK substantially augmented IL-23 production from IL-17-stimulated HDPFs. HDPFs expressed IL-17R and responded to IL-17 to produce IL-23 via the activation of the NF-κB and MAPK signalling pathways. The findings provide insights into the cellular mechanisms of the participation of IL-17 in the activation of HDPFs in inflamed pulp tissue. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Zinc rescues obesity-induced cardiac hypertrophy via stimulating metallothionein to suppress oxidative stress-activated BCL10/CARD9/p38 MAPK pathway.

PubMed

Wang, Shudong; Gu, Junlian; Xu, Zheng; Zhang, Zhiguo; Bai, Tao; Xu, Jianxiang; Cai, Jun; Barnes, Gregory; Liu, Qiu-Ju; Freedman, Jonathan H; Wang, Yonggang; Liu, Quan; Zheng, Yang; Cai, Lu

2017-06-01

Obesity often leads to obesity-related cardiac hypertrophy (ORCH), which is suppressed by zinc-induced inactivation of p38 mitogen-activated protein kinase (p38 MAPK). In this study, we investigated the mechanisms by which zinc inactivates p38 MAPK to prevent ORCH. Mice (4-week old) were fed either high fat diet (HFD, 60% kcal fat) or normal diet (ND, 10% kcal fat) containing variable amounts of zinc (deficiency, normal and supplement) for 3 and 6 months. P38 MAPK siRNA and the p38 MAPK inhibitor SB203580 were used to suppress p38 MAPK activity in vitro and in vivo, respectively. HFD activated p38 MAPK and increased expression of B-cell lymphoma/CLL 10 (BCL10) and caspase recruitment domain family member 9 (CARD9). These responses were enhanced by zinc deficiency and attenuated by zinc supplement. Administration of SB203580 to HFD mice or specific siRNA in palmitate-treated cardiomyocytes eliminated the HFD and zinc deficiency activation of p38 MAPK, but did not significantly impact the expression of BCL10 and CARD9. In cultured cardiomyocytes, inhibition of BCL10 expression by siRNA prevented palmitate-induced increased p38 MAPK activation and atrial natriuretic peptide (ANP) expression. In contrast, inhibition of p38 MAPK prevented ANP expression, but did not affect BCL10 expression. Deletion of metallothionein abolished the protective effect of zinc on palmitate-induced up-regulation of BCL10 and phospho-p38 MAPK. HFD and zinc deficiency synergistically induce ORCH by increasing oxidative stress-mediated activation of BCL10/CARD9/p38 MAPK signalling. Zinc supplement ameliorates ORCH through activation of metallothionein to repress oxidative stress-activated BCL10 expression and p38 MAPK activation. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Sphingosine kinase inhibitor suppresses IL-18-induced interferon-gamma production through inhibition of p38 MAPK activation in human NK cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheon, Soyoung; Song, Seok Bean; Jung, Minkyung

2008-09-12

Natural killer (NK) cells play an important role in the innate immune response. Interleukin-18 (IL-18) is a well-known interferon-gamma (IFN-{gamma} inducing factor, which stimulates immune response in NK and T cells. Sphingosine kinase (SPHK) catalyzes the formation of sphingosine 1-phosphate (S1P), which acts as a second messenger to function as an anti-apoptotic factor and proliferation stimulator of immune cells. In this study, to elucidate whether SPHK is involved in IL-18-induced IFN-{gamma} production, we measured IL-18-induced IFN-{gamma} production after pre-treatment with SPHK inhibitor (SKI) in NK-92MI cells. We found that IL-18-induced IFN-{gamma} expression was blocked by SKI pre-treatment in both mRNAmore » and protein levels. In addition, the increased IFN-{gamma} production by stimulation with IL-18 is mediated through both SPHK and p38 MAPK. To determine the upstream signals of SKI and p38 MAPK in IL-18-induced IFN-{gamma} production, phosphorylation levels of p38 MAPK was measured after SKI pre-treatment. As a result, inhibition of SPHK by SKI blocked phosphorylation of p38 MAPK, showing that SPHK activation by IL-18 is an upstream signal of p38 MAPK activation. Inhibition of SPHK by SKI also inhibited IL-18-induced IFN-{gamma} production in human primary NK cells. In conclusion, SPHK activation is an essential factor for IL-18-induced IFN-{gamma} production via p38 MAPK.« less

Ca2+-Stimulated Adenylyl Cyclases Regulate ERK-Dependent Activation of MSK1 During Fear Conditioning

PubMed Central

Sindreu, Carlos Balet; Scheiner, Zachary S.; Storm, Daniel R.

2007-01-01

The cAMP and ERK/MAP kinase (MAPK) signal transduction pathways are critical for hippocampus-dependent memory, a process that depends on CREB-mediated transcription. However, the extent of crosstalk between these pathways and the downstream CREB kinase activated during memory formation have not been elucidated. Here we report that PKA, MAPK, and MSK1, a CREB kinase, are co-activated in a subset of hippocampal CA1 pyramidal neurons following contextual fear conditioning. Activation of PKA, MAPK, MSK1, and CREB is absolutely dependent on Ca2+-stimulated adenylyl cyclase activity. We conclude that adenylyl cyclase activity supports the activation of MAPK, and that MSK1 is the major CREB kinase activated during training for contextual memory. PMID:17196532

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. © The Author(s) 2015.

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.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meili, Nicole; Christen, Verena

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 1 μM) and toxic concentrations (5 μM) for 24, 48, and 72 h. Transcripts of TNF-α and ER stress marker genes were strongly induced at 1 and 5 μM at all time-points. TNF-α led tomore » 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 2.5 nM, while HepG2 cells were insensitive up to 10 μM 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. - Highlights: • Toxicity of nodularin and its mechanisms of action are poorly understood. • We investigated mechanisms of nodularin toxicity in human liver cell lines and human hepatocytes. • We identified several pathways involved in nodularin toxicity. • Nodularin induces TNF-α, MAPK pathway and ER stress • These activated pathways may contribute to the hepatotoxic and tumorigenic action of nodularin.« less

Betacellulin overexpression in the mouse ovary leads to MAPK3/MAPK1 hyperactivation and reduces litter size by impairing fertilization.

PubMed

Gratao, Ana A; Dahlhoff, Maik; Sinowatz, Fred; Wolf, Eckhard; Schneider, Marlon R

2008-01-01

The epidermal growth factor receptor (EGFR) and its ligands are emerging as key molecules in regulating female reproduction. Here, we used a transgenic mouse model to evaluate whether and at which level of the reproduction cascade higher-than-normal levels of the EGFR ligand betacellulin (BTC) in the reproductive organs affect fertility. Western blots and immunohistochemistry revealed increased BTC levels in uterus and ovaries from transgenic females, particularly evident in granulosa cells of antral follicles. Onset of puberty, estrous cyclicity, and the anatomy and histology of reproductive organs at puberty were not altered as compared to control females. Fertility tests revealed a reduction (~50%) in litter size as the major reproductive deficit of transgenic females. Embryo implantation was delayed in transgenic females, but this was not the reason for the reduced litter size. Transgenic females produced a normal number of oocytes after natural ovulation. The in vivo fertilization rate was significantly reduced in untreated transgenic females but returned to normal levels after superovulation. Impaired oocyte fertilization in the absence of superovulation treatment was associated with MAPK3/MAPK1 hyperactivation in BTC transgenic ovaries, whereas similar levels of MAPK3/MAPK1 activation were detected in transgenic and control ovaries after superovulation treatment. Thus, tight regulation of MAPK3/MAPK1 activity appears to be essential for appropriate granulosa cell function during oocyte maturation. Our study identified hitherto unknown effects of BTC overabundance in reproduction and suggests BTC as a novel candidate protein for the modulation of fertility.

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

Cyclopropanyldehydrocostunolide LJ attenuates high glucose-induced podocyte injury by suppressing RANKL/RANK-mediated NF-κB and MAPK signaling pathways.

PubMed

Chen, Xiao-Wen; Liu, Wen-Ting; Wang, Yu-Xian; Chen, Wen-Jing; Li, Hong-Yu; Chen, Yi-Hua; Du, Xiao-Yan; Peng, Fen-Fen; Zhou, Wei-Dong; Xu, Zhao-Zhong; Long, Hai-Bo

2016-07-01

The aim of this research was to investigate the effects of cyclopropanyldehydrocostunolide (also named LJ), a derivative of sesquiterpene lactones (SLs), on high glucose (HG)-induced podocyte injury and the associated molecular mechanisms. Differentiated mouse podocytes were incubated in different treatments. The migration and albumin filtration of podocytes were examined by Transwell filters. The protein and mRNA levels of MCP-1 were measured using enzyme-linked immunosorbent assay (ELISA) and quantitative real-time PCR (q-PCR). Protein expression and phosphorylation were detected by western blot, and the nuclear translocation of NF-κB was performed with a confocal microscope. The gene expression of the receptor activator for NF-κB (RANK) was silenced by small interfering RNA (siRNA). Our results showed that HG enhanced migration, albumin filtration and MCP-1 expression in podocytes. At the molecular level, HG promoted the phosphorylation of NF-κB/p65, IKKβ, IκBα, mitogen-activated protein kinase (MAPK) and the nuclear translocation of p65. LJ reversed the effects of HG in a dose-dependent manner. Furthermore, our data provided the first demonstration that the receptor activator for NF-κB ligand (RANKL) and its cognate receptor RANK were overexpressed in HG-induced podocytes and were downregulated by LJ. RANK siRNA also attenuated HG-induced podocyte injury and markedly inhibited the activation of NF-κB and MAPK signaling pathways. LJ attenuates HG-induced podocyte injury by suppressing RANKL/RANK-mediated NF-κB and MAPK signaling pathways. Copyright © 2016 Elsevier Inc. All rights reserved.

Uric acid stimulates proliferative pathways in vascular smooth muscle cells through the activation of p38 MAPK, p44/42 MAPK and PDGFRβ.

PubMed

Kırça, M; Oğuz, N; Çetin, A; Uzuner, F; Yeşilkaya, A

2017-04-01

Hyperuricemia and angiotensin II (Ang II) may have a pathogenetic role in the development of hypertension and atherosclerosis as well as cardiovascular disease (CVD) and its prognosis. The purpose of this study was to investigate whether uric acid can induce proliferative pathways of vascular smooth muscle cell (VSMC) that are thought to be responsible for the development of CVD. The phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), p44/42 mitogen-activated protein kinase (p44/42 MAPK) and platelet-derived growth factor receptor β (PDGFRβ) was measured by Elisa and Western blot techniques to determine the activation of proliferative pathways in primary cultured VSMCs from rat aorta. Results demonstrated that uric acid can stimulate p38 MAPK, p44/42 MAPK and PDGFRβ phosphorylation in a time- and concentration-dependent manner. Furthermore, treatment of VSMCs with the angiotensin II type I receptor (AT1R) inhibitor losartan suppressed p38 MAPK and p44/42 MAPK induction by uric acid. The stimulatory effect of uric acid on p38 MAPK was higher compared to that of Ang II. The results of this study show for the first time that uric acid-induced PDGFRβ phosphorylation plays a crucial role in the development of CVDs and that elevated uric acid levels could be a potential therapeutical target in CVD patients.

Diarachidonoylphosphoethanolamine induces apoptosis of malignant pleural mesothelioma cells through a Trx/ASK1/p38 MAPK pathway.

PubMed

Tsuchiya, Ayako; Kaku, Yoshiko; Nakano, Takashi; Nishizaki, Tomoyuki

2015-11-01

1,2-Diarachidonoyl-sn-glycero-3-phosphoethanolamine (DAPE) induces both necrosis/necroptosis and apoptosis of NCI-H28 malignant pleural mesothelioma (MPM) cells. The present study was conducted to understand the mechanism for DAPE-induced apoptosis of NCI-H28 cells. DAPE induced caspase-independent apoptosis of NCI-H28 malignant pleural mesothelioma (MPM) cells, and the effect of DAPE was prevented by antioxidants or an inhibitor of NADPH oxidase (NOX). DAPE generated reactive oxygen species (ROS) and inhibited activity of thioredoxin (Trx) reductase (TrxR). DAPE decreased an association of apoptosis signal-regulating kinase 1 (ASK1) with thioredoxin (Trx), thereby releasing ASK1. DAPE activated p38 mitogen-activated protein kinase (MAPK), which was inhibited by an antioxidant or knocking-down ASK1. In addition, DAPE-induced NCI-H28 cell death was also prevented by knocking-down ASK1. Taken together, the results of the present study indicate that DAPE stimulates NOX-mediated ROS production and suppresses TrxR activity, resulting in the decrease of reduced Trx and the dissociation of ASK1 from a complex with Trx, allowing sequential activation of ASK1 and p38 MAPK, to induce apoptosis of NCI-H28 MPM cells. Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

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

PubMed

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

2014-01-01

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

Neurotrophin Promotes Neurite Outgrowth by Inhibiting Rif GTPase Activation Downstream of MAPKs and PI3K Signaling

PubMed Central

Tian, Xiaoxia; Yan, Huijuan; Li, Jiayi; Wu, Shuang; Wang, Junyu; Fan, Lifei

2017-01-01

Members of the well-known semaphorin family of proteins can induce both repulsive and attractive signaling in neural network formation and their cytoskeletal effects are mediated in part by small guanosine 5’-triphosphatase (GTPases). The aim of this study was to investigate the cellular role of Rif GTPase in the neurotrophin-induced neurite outgrowth. By using PC12 cells which are known to cease dividing and begin to show neurite outgrowth responding to nerve growth factor (NGF), we found that semaphorin 6A was as effective as nerve growth factor at stimulating neurite outgrowth in PC12 cells, and that its neurotrophic effect was transmitted through signaling by mitogen-activated protein kinases (MAPKs) and phosphatidylinositol-3-kinase (PI3K). We further found that neurotrophin-induced neurite formation in PC12 cells could be partially mediated by inhibition of Rif GTPase activity downstream of MAPKs and PI3K signaling. In conclusion, we newly identified Rif as a regulator of the cytoskeletal rearrangement mediated by semaphorins. PMID:28098758

Targeting the MEF2-Like Transcription Factor Smp1 by the Stress-Activated Hog1 Mitogen-Activated Protein Kinase

PubMed Central

Nadal, Eulàlia de; Casadomé, Laura; Posas, Francesc

2003-01-01

Exposure of Saccharomyces cerevisiae to increases in extracellular osmolarity activates the stress-activated Hog1 mitogen-activated protein kinase (MAPK), which is essential for cell survival upon osmotic stress. Yeast cells respond to osmotic stress by inducing the expression of a very large number of genes, and the Hog1 MAPK plays a critical role in gene transcription upon stress. To understand how Hog1 controls gene expression, we designed a genetic screen to isolate new transcription factors under the control of the MAPK and identified the MEF2-like transcription factor, Smp1, as a target for Hog1. Overexpression of SMP1 induced Hog1-dependent expression of osmoresponsive genes such as STL1, whereas smp1Δ cells were defective in their expression. Consistently, smp1Δ cells displayed reduced viability upon osmotic shock. In vivo coprecipitation and phosphorylation studies showed that Smp1 and Hog1 interact and that Smp1 is phosphorylated upon osmotic stress in a Hog1-dependent manner. Hog1 phosphorylated Smp1 in vitro at the C-terminal region. Phosphorylation of Smp1 by the MAPK is essential for its function, since a mutant allele unable to be phosphorylated by the MAPK displays impaired stress responses. Thus, our data indicate that Smp1 acts downstream of Hog1, controlling a subset of the responses induced by the MAPK. Moreover, Smp1 concentrates in the nucleus during the stationary phase, and the lack of SMP1 results in cells that lose viability in the stationary phase. Localization of Smp1 depends on HOG1, and consistently, hog1Δ cells also lose viability during this growth phase. These data suggest that Smp1 could be mediating a role for the Hog1 MAPK during the stationary phase. PMID:12482976

Role of Sigma-1 Receptor/p38 MAPK Inhibition in Acupoint Catgut Embedding-Mediated Analgesic Effects in Complete Freund's Adjuvant-Induced Inflammatory Pain.

PubMed

Du, Kairong; Wang, Xue; Chi, Laiting; Li, Wenzhi

2017-08-01

The endoplasmic reticulum chaperone protein Sigma-1 receptor (Sig-1 R) and mitogen-activated protein kinases (MAPKs) are involved in the mechanism of pain. Acupoint stimulation exerts an exact antihyperalgesic effect in inflammatory pain. However, whether Sig-1 R and MAPKs are associated with the acupoint stimulation-induced analgesic effects is not clear. This study investigated the analgesic effect of acupoint catgut embedding (ACE) and the inhibition of Sig-1 R and MAPKs in ACE analgesia. Rats were prepared with intrathecal catheter implantation. ACE was applied to bilateral "Kunlun" (BL60), "Zusanli" (ST36), and "Sanyinjiao" (SP6) acupoints in the rat model of inflammatory pain (complete Freund's adjuvant [CFA] intraplantar injection). Then, Sig-1R agonist PRE084 or saline was intrathecally given daily. The paw withdrawal thresholds and paw edema were measured before CFA injection and at 1, 3, and 5 day after CFA injection. Western bolt was used to evaluate the protein expression of spinal Sig-1R, p38MAPK, and extracellular signal-regulated kinase (ERK), and immunohistochemistry of Sig-1R was detected at 1, 3, and 5 days after CFA injection. ACE exhibited specific analgesic effects. ACE increased paw withdrawal thresholds and markedly decreased CFA-induced paw edema at 1, 3, and 5 days. ACE downregulated the protein expression of Sig-1R, which was increased significantly at 1, 3, and 5 days after CFA injection. ACE decreased the expression of p38 MAPK and ERK at 1 and 3 days but not at 5 days. However, an injection of Sig-1R agonist PRE084 markedly reversed these alterations, except ERK expression. The present study demonstrated that ACE exhibited antihyperalgesic effects via the inhibition of the Sig-1R that modulated p38 MAPK, but not ERK, expression in the CFA-induced inflammatory pain model in rats.

γ-Oryzanol suppresses COX-2 expression by inhibiting reactive oxygen species-mediated Erk1/2 and Egr-1 signaling in LPS-stimulated RAW264.7 macrophages.

PubMed

Shin, Soon Young; Kim, Heon-Woong; Jang, Hwan-Hee; Hwang, Yu-Jin; Choe, Jeong-Sook; Kim, Jung-Bong; Lim, Yoongho; Lee, Young Han

2017-09-16

Cyclooxygenase (COX)-2 produces prostanoids, which contribute to inflammatory responses. Nuclear factor (NF)-κB is a key transcription factor mediating COX-2 expression. γ-Oryzanol is an active component in rice bran oil, which inhibits lipopolysaccharide (LPS)-mediated COX-2 expression by inhibiting NF-κB. However, the inhibition of COX-2 expression by γ-oryzanol independently of NF-κB is poorly understood. We found that LPS upregulated Egr-1 expression at the transcriptional level. Forced expression of Egr-1 trans-activated the Cox-2 promoter independently of NF-κB. In contrast, silencing of Egr-1 abrogated LPS-mediated COX-2 expression. LPS produced reactive oxygen species (ROS), which, in turn, induced Egr-1 expression via the Erk1/2 MAPK pathway. ROS scavenging activity of γ-oryzanol suppressed Egr-1 expression by inhibiting the Erk1/2 MAPK pathway. Our results suggest that γ-oryzanol inhibits LPS-mediated COX-2 expression by suppressing Erk1/2-mediated Egr-1 expression. This study supports that γ-oryzanol may be useful for ameliorating LPS-mediated inflammatory responses. Copyright © 2017 Elsevier Inc. All rights reserved.

Nicotine stimulates urokinase-type plasminogen activator receptor expression and cell invasiveness through mitogen-activated protein kinase and reactive oxygen species signaling in ECV304 endothelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khoi, Pham Ngoc; Park, Jung Sun; Kim, Nam Ho

Urokinase-type plasminogen activator receptor (uPAR) expression is elevated during inflammation, tissue remodeling and in many human cancers. This study investigated the effect of nicotine, a major alkaloid in tobacco, on uPAR expression and cell invasiveness in ECV304 endothelial cells. Nicotine stimulated uPAR expression in a dose-dependent manner and activated extracellular signal-regulated kinases-1/2 (Erk-1/2), c-Jun amino-terminal kinase (JNK) and p38 mitogen activated protein kinase (MAPK). Specific inhibitors of MEK-1 (PD98059) and JNK (SP600125) inhibited the nicotine-induced uPAR expression, while the p38 MAPK inhibitor SB203580 did not. Expression vectors encoding dominant negative MEK-1 (pMCL-K97M) and JNK (TAM67) also prevented nicotine-induced uPAR promotermore » activity. The intracellular hydrogen peroxide (H{sub 2}O{sub 2}) content was increased by nicotine treatment. The antioxidant N-acetylcysteine prevented nicotine-activated production of reactive oxygen species (ROS) and uPAR expression. Furthermore, exogenous H{sub 2}O{sub 2} increased uPAR mRNA expression. Deleted and site-directed mutagenesis demonstrated the involvement of the binding sites of transcription factor nuclear factor-kappaB (NF-κB) and activator protein (AP)-1 in the nicotine-induced uPAR expression. Studies with expression vectors encoding mutated NF-κB signaling molecules and AP-1 decoy confirmed that NF-κB and AP-1 were essential for the nicotine-stimulated uPAR expression. MAPK (Erk-1/2 and JNK) and ROS functioned as upstream signaling molecules in the activation of AP-1 and NF-κB, respectively. In addition, ECV304 endothelial cells treated with nicotine displayed markedly enhanced invasiveness, which was partially abrogated by uPAR neutralizing antibodies. The data indicate that nicotine induces uPAR expression via the MAPK/AP-1 and ROS/NF-κB signaling pathways and, in turn, stimulates invasiveness in human ECV304 endothelial cells. -- Highlights: ► Endothelial

Functional Roles of p38 Mitogen-Activated Protein Kinase in Macrophage-Mediated Inflammatory Responses

PubMed Central

Yang, Yanyan; Yu, Tao; Sung, Gi-Ho; Yoo, Byong Chul

2014-01-01

Inflammation is a natural host defensive process that is largely regulated by macrophages during the innate immune response. Mitogen-activated protein kinases (MAPKs) are proline-directed serine and threonine protein kinases that regulate many physiological and pathophysiological cell responses. p38 MAPKs are key MAPKs involved in the production of inflammatory mediators, including tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2). p38 MAPK signaling plays an essential role in regulating cellular processes, especially inflammation. In this paper, we summarize the characteristics of p38 signaling in macrophage-mediated inflammation. In addition, we discuss the potential of using inhibitors targeting p38 expression in macrophages to treat inflammatory diseases. PMID:24771982

Six1 overexpression at early stages of HPV16-mediated transformation of human keratinocytes promotes differentiation resistance and EMT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Hanwen; Pirisi, Lucia; Creek, Kim E., E-mail: creekk@sccp.sc.edu

Previous studies in our laboratory discovered that SIX1 mRNA expression increased during in vitro progression of HPV16-immortalized human keratinocytes (HKc/HPV16) toward a differentiation-resistant (HKc/DR) phenotype. In this study, we explored the role of Six1 at early stages of HPV16-mediated transformation by overexpressing Six1 in HKc/HPV16. We found that Six1 overexpression in HKc/HPV16 increased cell proliferation and promoted cell migration and invasion by inducing epithelial–mesenchymal transition (EMT). Moreover, the overexpression of Six1 in HKc/HPV16 resulted in resistance to serum and calcium-induced differentiation, which is the hallmark of the HKc/DR phenotype. Activation of MAPK in HKc/HPV16 overexpressing Six1 is linked to resistancemore » to calcium-induced differentiation. In conclusion, this study determined that Six1 overexpression resulted in differentiation resistance and promoted EMT at early stages of HPV16-mediated transformation of human keratinocytes. - Highlights: • Six1 expression increases during HPV16-mediated transformation. • Six1 overexpression causes differentiation resistance in HPV16-immortalized cells. • Six1 overexpression in HPV16-immortalized keratinocytes activates MAPK. • Activation of MAPK promotes EMT and differentiation resistance. • Six1 overexpression reduces Smad-dependent TGF-β signaling.« less

NF-κB– and AP-1–Mediated DNA Looping Regulates Osteopontin Transcription in Endotoxin-Stimulated Murine Macrophages

PubMed Central

Zhao, Wei; Wang, Lijuan; Zhang, Meng; Wang, Peng; Zhang, Lei; Yuan, Chao; Qi, Jianni; Qiao, Yu; Kuo, Paul C.; Gao, Chengjiang

2013-01-01

Osteopontin (OPN) is expressed by various immune cells and modulates both innate and adaptive immune responses. However, the molecular mechanisms that control opn gene expression, especially at the chromatin level, remain largely unknown. We have previously demonstrated many specific cis- and trans-regulatory elements that determine the extent of endotoxin (LPS)-mediated induction of OPN synthesis in murine macrophages. In the present study, we confirm that NF-κB also plays an important role in the setting of LPS-stimulated OPN expression through binding to a distal regulatory element. Importantly, we demonstrate that LPS stimulates chromosomal loops in the OPN promoter between NF-κB binding site and AP-1 binding site using chromosome conformation capture technology. The crucial role of NF-κB and AP-1 in LPS-stimulated DNA looping was confirmed, as small interfering RNA knock-down of NF-κB p65 and AP-1 c-Jun exhibited decreased levels of DNA looping. Furthermore, we demonstrate that p300 can form a complex with NF-κB and AP-1 and is involved in DNA looping and LPS-induced OPN expression. Therefore, we have identified an essential mechanism to remodel the local chromatin structures and spatial conformations to regulate LPS-induced OPN expression. PMID:21257959

Bacteroides fragilis Enterotoxin Induces Formation of Autophagosomes in Endothelial Cells but Interferes with Fusion with Lysosomes for Complete Autophagic Flux through a Mitogen-Activated Protein Kinase-, AP-1-, and C/EBP Homologous Protein-Dependent Pathway.

PubMed

Ko, Su Hyuk; Jeon, Jong Ik; Myung, Hyun Soo; Kim, Young-Jeon; Kim, Jung Mogg

2017-10-01

Bacteroides fragilis enterotoxin (BFT), a virulence factor of enterotoxigenic B. fragilis (ETBF), plays an essential role in mucosal inflammation. Although autophagy contributes to the pathogenesis of diverse infectious diseases, little is known about autophagy in ETBF infection. This study was conducted to investigate the role of BFT in the autophagic process in endothelial cells (ECs). Stimulation of human umbilical vein ECs (HUVECs) with BFT increased light chain 3 protein II (LC3-II) conversion from LC3-I and protein expression of p62, Atg5, and Atg12. In addition, BFT-exposed ECs showed increased indices of autophagosomal fusion with lysosomes such as LC3-lysosome-associated protein 2 (LAMP2) colocalization and the percentage of red vesicles monitored by the expression of dual-tagged LC3B. BFT also upregulated expression of C/EBP homologous protein (CHOP), and inhibition of CHOP significantly increased indices of autophagosomal fusion with lysosomes. BFT activated an AP-1 transcription factor, in which suppression of AP-1 activity significantly downregulated CHOP and augmented autophagosomal fusion with lysosomes. Furthermore, suppression of Jun N-terminal protein kinase (JNK) mitogen-activated protein kinase (MAPK) significantly inhibited the AP-1 and CHOP signals, leading to an increase in autophagosomal fusion with lysosomes in BFT-stimulated ECs. These results suggest that BFT induced accumulation of autophagosomes in ECs, but activation of a signaling pathway involving JNK, AP-1, and CHOP may interfere with complete autophagy. Copyright © 2017 American Society for Microbiology.

Deoxynivalenol induced mouse skin cell proliferation and inflammation via MAPK pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishra, Sakshi; Department of Biochemistry, Banaras Hindu University; Tripathi, Anurag

Several toxicological manifestations of deoxynivalenol (DON), a mycotoxin, are well documented; however, dermal toxicity is not yet explored. The effect of topical application of DON to mice was studied using markers of skin proliferation, inflammation and tumor promotion. Single topical application of DON (84–672 nmol/mouse) significantly enhanced dermal hyperplasia and skin edema. DON (336 and 672 nmol) caused significant enhancement in [{sup 3}H]-thymidine uptake in DNA along with increased myeloperoxidase and ornithine decarboxylase activities, suggesting tissue inflammation and cell proliferation. Furthermore, DON (168 nmol) caused enhanced expression of RAS, and phosphorylation of PI3K/Akt, ERK, JNK and p38 MAPKs. DON exposuremore » also showed activation of transcription factors, c-fos, c-jun and NF-κB along with phosphorylation of IkBα. Enhanced phosphorylation of NF-κB by DON caused over expression of target proteins, COX-2, cyclin D1 and iNOS in skin. Though a single topical application of DMBA followed by twice weekly application of DON (84 and 168 nmol) showed no tumorigenesis after 24 weeks, however, histopathological studies suggested hyperplasia of the epidermis and hypertrophy of hair follicles. Interestingly, intestine was also found to be affected as enlarged Peyer's patches were observed, suggesting inflammatory effects which were supported by elevation of inflammatory cytokines after 24 weeks of topical application of DON. These results suggest that DON induced cell proliferation in mouse skin is through the activation of MAPK signaling pathway involving transcription factors NFκB and AP-1, further leading to transcriptional activation of downstream target proteins c-fos, c-jun, cyclin D1, iNOS and COX-2 which might be responsible for its inflammatory potential. - Highlights: • Topical application of DON enhanced epidermal inflammation and cell proliferation. • DON follows PI3K/Akt/MAPK signaling cascade, with activation of AP-1 and

Fumaric acid attenuates the eotaxin-1 expression in TNF-α-stimulated fibroblasts by suppressing p38 MAPK-dependent NF-κB signaling.

PubMed

Roh, Kyung-Baeg; Jung, Eunsun; Park, Deokhoon; Lee, Jongsung

2013-08-01

Eotaxin-1 is a potent chemoattractant for eosinophils and a critical mediator during the development of eosinophilic inflammation. Fumaric acid is an intermediate product of the citric acid cycle, which is source of intracellular energy. Although fumaric acid ameliorates psoriasis and multiple sclerosis, its involvement in eotaxin-1-mediated effects has not been assessed. In this study, we investigated the effects of fumaric acid on eotaxin-1 expression in a mouse fibroblast cell line. We found that fumaric acid significantly inhibited tumor necrosis factor-α (TNF-α-induced eotaxin-1 expression. This fumaric acid effect was mediated through the inhibition of p38 mitogen-activated protein kinase (MAPK)-dependent nuclear factor (NF)-κB signaling. We also found that fumaric acid operates downstream of MEKK3 during TNF-α-induced NF-κB signaling, which upregulated eotaxin-1 expression. In addition, fumaric acid attenuated expression of CC-chemokine receptor 3 (CCR3), an eotaxin-1 receptor, and adhesion molecules that play important roles in eosinophil binding to induce allergic inflammation. Taken together, these findings indicate that inhibiting TNF-α-induced eotaxin-1 expression by fumaric acid occurs primarily through suppression of NF-κB signaling, which is mediated by inhibiting p38 MAPK and suggest that fumaric acid may be used as a complementary treatment option for eotaxin-1-mediated diseases. Copyright © 2013 Elsevier Ltd. All rights reserved.

Amarogentin, a secoiridoid glycoside, abrogates platelet activation through PLC γ 2-PKC and MAPK pathways.

PubMed

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

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 PLC γ2-PKC cascade and MAPK pathway. Our findings suggest that amarogentin may offer therapeutic potential for preventing or treating thromboembolic disorders.

Pathogen exploitation of an abscisic acid- and jasmonate-inducible MAPK phosphatase and its interception by Arabidopsis immunity.

PubMed

Mine, Akira; Berens, Matthias L; Nobori, Tatsuya; Anver, Shajahan; Fukumoto, Kaori; Winkelmüller, Thomas M; Takeda, Atsushi; Becker, Dieter; Tsuda, Kenichi

2017-07-11

Phytopathogens promote virulence by, for example, exploiting signaling pathways mediated by phytohormones such as abscisic acid (ABA) and jasmonate (JA). Some plants can counteract pathogen virulence by invoking a potent form of immunity called effector-triggered immunity (ETI). Here, we report that ABA and JA mediate inactivation of the immune-associated MAP kinases (MAPKs), MPK3 and MPK6, in Arabidopsis thaliana ABA induced expression of genes encoding the protein phosphatases 2C (PP2Cs), HAI1 , HAI2 , and HAI3 through ABF/AREB transcription factors. These three HAI PP2Cs interacted with MPK3 and MPK6 and were required for ABA-mediated MPK3/MPK6 inactivation and immune suppression. The bacterial pathogen Pseudomonas syringae pv. tomato ( Pto ) DC3000 activates ABA signaling and produces a JA-mimicking phytotoxin, coronatine (COR), that promotes virulence. We found that Pto DC3000 induces HAI1 through COR-mediated activation of MYC2, a master transcription factor in JA signaling. HAI1 dephosphorylated MPK3 and MPK6 in vitro and was necessary for COR-mediated suppression of MPK3/MPK6 activation and immunity. Intriguingly, upon ETI activation, A. thaliana plants overcame the HAI1-dependent virulence of COR by blocking JA signaling. Finally, we showed conservation of induction of HAI PP2Cs by ABA and JA in other Brassicaceae species. Taken together, these results suggest that ABA and JA signaling pathways, which are hijacked by the bacterial pathogen, converge on the HAI PP2Cs that suppress activation of the immune-associated MAPKs. Also, our data unveil interception of JA-signaling activation as a host counterstrategy against the bacterial suppression of MAPKs during ETI.

Mitogen-activated protein kinase signaling pathways promote low-density lipoprotein receptor-related protein 1-mediated internalization of beta-amyloid protein in primary cortical neurons.

PubMed

Yang, Wei-Na; Ma, Kai-Ge; Qian, Yi-Hua; Zhang, Jian-Shui; Feng, Gai-Feng; Shi, Li-Li; Zhang, Zhi-Chao; Liu, Zhao-Hui

2015-07-01

Mounting evidence suggests that the pathological hallmarks of Alzheimer's disease (AD) are caused by the intraneuronal accumulation of beta-amyloid protein (Aβ). Reuptake of extracellular Aβ is believed to contribute significantly to the intraneuronal Aβ pool in the early stages of AD. Published reports have claimed that the low-density lipoprotein receptor-related protein 1 (LRP1) mediates Aβ1-42 uptake and lysosomal trafficking in GT1-7 neuronal cells and mouse embryonic fibroblast non-neuronal cells. However, there is no direct evidence supporting the role of LRP1 in Aβ internalization in primary neurons. Our recent study indicated that p38 MAPK and ERK1/2 signaling pathways are involved in regulating α7 nicotinic acetylcholine receptor (α7nAChR)-mediated Aβ1-42 uptake in SH-SY5Y cells. This study was designed to explore the regulation of MAPK signaling pathways on LRP1-mediated Aβ internalization in neurons. We found that extracellular Aβ1-42 oligomers could be internalized into endosomes/lysosomes and mitochondria in cortical neurons. Aβ1-42 and LRP1 were also found co-localized in neurons during Aβ1-42 internalization, and they could form Aβ1-42-LRP1 complex. Knockdown of LRP1 expression significantly decreased neuronal Aβ1-42 internalization. Finally, we identified that p38 MAPK and ERK1/2 signaling pathways regulated the internalization of Aβ1-42 via LRP1. Therefore, these results demonstrated that LRP1, p38 MAPK and ERK1/2 mediated the internalization of Aβ1-42 in neurons and provided evidence that blockade of LRP1 or inhibitions of MAPK signaling pathways might be a potential approach to lowering brain Aβ levels and served a potential therapeutic target for AD. Copyright © 2015 Elsevier Ltd. All rights reserved.

Magnolol Inhibits RANKL-induced osteoclast differentiation of raw 264.7 macrophages through heme oxygenase-1-dependent inhibition of NFATc1 expression.

PubMed

Lu, Sheng-Hua; Chen, Tso-Hsiao; Chou, Tz-Chong

2015-01-23

Magnolol (1) isolated from Magnolia officinalis exhibits many beneficial effects such as anti-inflammatory and antioxidant activity. The aim of this study was to evaluate the effects of magnolol (1) on RANKL-induced osteoclast differentiation and investigate the underlying molecular mechanisms. Treatment with magnolol (1) significantly inhibited osteoclast differentiation of RAW 264.7 macrophages and bone-resorbing activity of osteoclasts in the RANKL-induced system. Moreover, RANKL-activated JNK/ERK/AP-1 and NF-κB signaling, ROS formation, and NFATc1 activation were attenuated by magnolol (1). A novel finding of this study is that magnolol (1) can increase heme oxygenase-1 (HO-1) expression and Nrf2 activation in RANKL-stimulated cells. Blocking HO-1 activity with tin protoporphyrin IX markedly reversed magnolol (1)-mediated inhibition of osteoclast differentiation, NFATc1 nuclear translocation, and MMP-9 activity, suggesting that HO-1 contributes to the attenuation of NFATc1-mediated osteoclastogenesis by magnolol (1). Therefore, the inhibitory effect of magnolol (1) on osteoclast differentiation is due to inhibition of MAPK/c-fos/AP-1 and NF-κB signaling as well as ROS production and up-regulation of HO-1 expression, which ultimately suppresses NFATc1 induction. These findings indicate that magnolol (1) may have potential to treat bone diseases associated with excessive osteoclastogenesis.

The role of MAPK signal transduction pathways in the response to oxidative stress in the fungal pathogen Candida albicans: implications in virulence.

PubMed

de Dios, Carmen Herrero; Román, Elvira; Monge, Rebeca Alonso; Pla, Jesús

2010-12-01

In recent years, Mitogen-Activated Protein Kinase (MAPK) pathways have emerged as major regulators of cellular physiology. In the fungal pathogen Candida albicans, three different MAPK pathways have been characterized in the last years. The HOG pathway is mainly a stress response pathway that is activated in response to osmotic and oxidative stress and also participates regulating other pathways. The SVG pathway (or mediated by the Cek1 MAPK) is involved in cell wall formation under vegetative and filamentous growth, while the Mkc1-mediated pathway is involved in cell wall integrity. Oxidative stress is one of the types of stress that every fungal cell has to face during colonization of the host, where the cell encounters both hypoxia niches (i.e. gut) and high concentrations of reactive oxygen species (upon challenge with immune cells). Two pathways have been shown to be activated in response to oxidative stress: the HOG pathway and the MKC1-mediated pathway while the third, the Cek1 pathway is deactivated. The timing, kinetics, stimuli and functional responses generated upon oxidative stress differ among them; however, they have essential functional consequences that severely influence pathogenesis. MAPK pathways are, therefore, valuable targets to be explored in antifungal research.

MAPK1 is required for establishing the pattern of cell proliferation and for cell survival during lens development

PubMed Central

Upadhya, Dinesh; Ogata, Masato; Reneker, Lixing W.

2013-01-01

The mitogen-activated protein kinases (MAPKs; also known as ERKs) are key intracellular signaling molecules that are ubiquitously expressed in tissues and were assumed to be functionally equivalent. Here, we use the mouse lens as a model system to investigate whether MAPK1 plays a specific role during development. MAPK3 is known to be dispensable for lens development. We demonstrate that, although MAPK1 is uniformly expressed in the lens epithelium, its deletion significantly reduces cell proliferation in the peripheral region, an area referred to as the lens germinative zone in which most active cell division occurs during normal lens development. By contrast, cell proliferation in the central region is minimally affected by MAPK1 deletion. Cell cycle regulators, including cyclin D1 and survivin, are downregulated in the germinative zone of the MAPK1-deficient lens. Interestingly, loss of MAPK1 subsequently induces upregulation of phosphorylated MAPK3 (pMAPK3) levels in the lens epithelium; however, this increase in pMAPK3 is not sufficient to restore cell proliferation in the germinative zone. Additionally, MAPK1 plays an essential role in epithelial cell survival but is dispensable for fiber cell differentiation during lens development. Our data indicate that MAPK1/3 control cell proliferation in the lens epithelium in a spatially defined manner; MAPK1 plays a unique role in establishing the highly mitotic zone in the peripheral region, whereas the two MAPKs share a redundant role in controlling cell proliferation in the central region of the lens epithelium. PMID:23482492

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

PubMed Central

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

2012-01-01

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

Aesculin inhibits matrix metalloproteinase-9 expression via p38 mitogen activated protein kinase and activator protein 1 in lipopolysachride-induced RAW264.7 cells.

PubMed

Choi, Hee-Jung; Chung, Tae-Wook; Kim, Jai-Eun; Jeong, Han-Sol; Joo, Myungsoo; Cha, Jaeho; Kim, Cheorl-Ho; Ha, Ki-Tae

2012-11-01

Expression of matrix metalloproteinase 9 (MMP-9) may contribute to inflammatory conditions such as arthritis, hepatitis, atherosclerosis, and pulmonary fibrosis, which involves the destruction of the extracellular matrix (ECM). Macrophages stimulated with lipopolysaccharide (LPS) express MMP-9 through the nuclear factor-kappa B (NF-κB) and activator protein 1 (AP-1) signaling pathways. Aesculin, a 6,7-dihydroxycoumarin-6-O-beta-glucopyranoside, has been highlighted for its anti-hepatotoxic, hypouricemic, antioxidative, photo-protective, and anti-apoptotic properties. In this study, we investigated the effects of aesculin on LPS-stimulated MMP-9 production and its regulatory mechanism by using murine macrophage RAW264.7 cells. Aesculin did not trigger any significant cytotoxic effect on RAW264.7 cells at concentration up to 150 μM. Secretion and expression levels of MMP-9, which were highly elevated by LPS treatment, were reduced by the addition of aesculin in a dose-dependent manner. However, gelatinolytic activity of MMP-9 was not reduced by aesculin. Luciferase activity assays and electrophoretic mobility shift assays using RAW264.7 cells showed that the inhibition of MMP-9 expression by aesculin was mediated by AP-1 rather than NF-κB. In addition, aesculin inhibited phosphorylation of p38 MAPK and subsequent activation of c-fos, a component of AP-1 transcription factor, but not JNK, ERK1/2, and c-jun. These findings suggest that aesculin is a potent drug candidate that protects against the inflammatory destruction of ECM. Copyright © 2012 Elsevier B.V. All rights reserved.

Effects of 17β-estradiol on the release of monocyte chemotactic protein-1 and MAPK activity in monocytes stimulated with peritoneal fluid from endometriosis patients.

PubMed

Lee, Dong-Hyung; Kim, Seung-Chul; Joo, Jong-Kil; Kim, Hwi-Gon; Na, Young-Jin; Kwak, Jong-Young; Lee, Kyu-Sup

2012-03-01

Hormones and inflammation have been implicated in the pathological process of endometriosis; therefore, we investigated the combined effects of 17β-estradiol (E2) and peritoneal fluid obtained from patients with endometriosis (ePF) or a control peritoneal fluid (cPF) obtained from patients without endometriosis on the release of monocyte chemotactic protein-1 (MCP-1) by monocytes and the role of signaling pathways. Monocytes were cultured with ePF and cPF in the presence of E2; the MCP-1 levels in the supernatants were then measured by ELISA. In addition, mitogen activated protein kinase (MAPK) activation was measured by Western blotting of phosphorylated proteins. E2 down-regulated MCP-1 release by lipopolysaccharide- or cPF-treated monocytes, but failed to suppress its release by ePF-treated monocytes. The release of MCP-1 by ePF- and cPF-treated monocytes was efficiently abrogated by p38 mitogen activated protein kinase (MAPK) inhibitors; however, the MCP-1 release by cPF-treated monocytes, but not by ePF-treated monocytes, was blocked by a MAPK kinase inhibitor. In addition, ePF and cPF induced the phosphorylation of extracellular stress regulated kinase (ERK)1/2, p38 MAPK and c-Jun N-terminal kinase (JNK). E2 decreased the phosphorylation of p38 MAPK, but not ERK1/2 in ePF-treated monocytes; however, E2 decreased the phosphorylation of p38 MAPK, ERK1/2 and JNK in cPF-treated monocytes. The ability of E2 to modulate MCP-1 production is impaired in ePF-treated monocytes, which may be related to regulation of MAPK activity. These findings suggest that the failure of E2 to suppress ePF-treated production of MCP-1 may be involved in the pathogenesis of endometriosis. © 2012 The Authors. Journal of Obstetrics and Gynaecology Research © 2012 Japan Society of Obstetrics and Gynecology.

IGF-II-mediated downregulation of peroxisome proliferator-activated receptor-γ coactivator-1α in myoblast cells involves PI3K/Akt/FoxO1 signaling pathway.

PubMed

Mu, Xiaoyu; Qi, Weihong; Liu, Yunzhang; Zhou, Jianfeng; Li, Yun; Rong, Xiaozhi; Lu, Ling

2017-08-01

Insulin-like growth factor II (IGF-II) can stimulate myogenesis and is critically involved in skeletal muscle differentiation. The presence of negative regulators of this process, however, is not well explored. Here, we showed that in myoblast cells, IGF-II negatively regulated peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) mRNA expression, while constitutive expression of PGC-1α induced myoblast differentiation. These results suggest that the negative regulation of PGC-1α by IGF-II may act as a negative feedback mechanism in IGF-II-induced myogenic differentiation. Reporter assays demonstrated that IGF-II suppresses the basal PGC-1α promoter activity. Blocking the IGF-II signaling pathway increased the endogenous PGC-1α levels. In addition, pharmacological inhibition of PI3 kinase activity prevented the downregulation of PGC-1α but the activation of mTOR was not required for this process. Importantly, further analysis showed that forkhead transcription factor FoxO1 contributes to mediating the effects of IGF-II on PGC-1 promoter activity. These findings indicate that IGF-II reduces PGC-1α expression in skeletal muscle cells through a mechanism involving PI3K-Akt-FoxO1 but not p38 MAPK or Erk1/2 MAPK pathways.

Silica nanoparticles inhibit macrophage activity and angiogenesis via VEGFR2-mediated MAPK signaling pathway in zebrafish embryos.

PubMed

Duan, Junchao; Hu, Hejing; Feng, Lin; Yang, Xiaozhe; Sun, Zhiwei

2017-09-01

The safety evaluation of silica nanoparticles (SiNPs) are getting great attention due to its widely-used in food sciences, chemical industry and biomedicine. However, the adverse effect and underlying mechanisms of SiNPs on cardiovascular system, especially on angiogenesis is still unclear. This study was aimed to illuminate the possible mechanisms of SiNPs on angiogenesis in zebrafish transgenic lines, Tg(fli-1:EGFP) and Albino. SiNPs caused the cardiovascular malformations in a dose-dependent manner via intravenous microinjection. The incidences of cardiovascular malformations were observed as: Pericardial edema > Bradycardia > Blood deficiency. The area of subintestinal vessels (SIVs) was significant reduced in SiNPs-treated groups, accompanied with the weaken expression of vascular endothelial cells in zebrafish embryos. Using neutral red staining, the quantitative number of macrophage was declined; whereas macrophage inhibition rate was elevated in a dose-dependent way. Furthermore, SiNPs significantly decreased the mRNA expression of macrophage activity related gene, macrophage migration inhibitory factor (MIF) and the angiogenesis related gene, vascular endothelial growth factor receptor 2 (VEGFR2). The protein levels of p-Erk1/2 and p-p38 MAPK were markedly decreased in zebrafish exposed to SiNPs. Our results implicate that SiNPs inhibited the macrophage activity and angiogenesis via the downregulation of MAPK singaling pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

Liu, G; Bibus, D M; Bode, A M; Ma, W Y; Holman, R T; Dong, Z

2001-06-19

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 (omega3) fatty acids, including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), can effectively reduce the risk of skin cancer whereas omega 6 (omega6) 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 omega3 fatty acids EPA and DHA and of the omega6 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 omega3 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 omega6 to omega3 fatty acids may be a significant factor in mediating tumor development.

Activation of the Rb/E2F1 pathway by the nonproliferative p38 MAPK during Fas (APO1/CD95)-mediated neuronal apoptosis.

PubMed

Hou, Sheng T; Xie, Xiaoqi; Baggley, Anne; Park, David S; Chen, Gao; Walker, Teena

2002-12-13

Aberrant activation of the Rb/E2F1 pathway in cycling cells, in response to mitogenic or nonmitogenic stress signals, leads to apoptosis through hyperphosphorylation of Rb. To test whether in postmitotic neurons the Rb/E2F1 pathway can be activated by the nonmitogenic stress signaling, we examined the role of the p38 stress-activated protein kinase (SAPK) in regulating Rb phosphorylation in response to Fas (CD95/APO1)-mediated apoptosis of cultured cerebellar granule neurons (CGNs). Anti-Fas antibody induced a dramatic and early activation of p38. Activated p38 was correlated with the induction of hyperphosphorylation of both endogenous and exogenous Rb. The p38-selective inhibitor, SB203580, attenuated such an increase in pRb phosphorylation and significantly protected CGNs from Fas-induced apoptosis. The cyclin-dependent kinase-mediated Rb phosphorylation played a lesser role in this neuronal death paradigm, since cyclin-dependent kinase inhibitors, such as olomoucine, roscovitine, and flavopiridol, did not significantly prevent anti-Fas antibody-evoked neuronal apoptosis. Hyperphosphorylation of Rb by p38 SAPK resulted in the release of Rb-bound E2F1. Increased E2F1 modulated neuronal apoptosis, since E2F1-/- CGNs were significantly less susceptible to Fas-mediated apoptosis in comparison with the wild-type CGNs. Taken together, these studies demonstrate that neuronal Rb/E2F1 is modulated by the nonproliferative p38 SAPK in Fas-mediated neuronal apoptosis.

Cross-talk between Smad and p38 MAPK signalling in transforming growth factor {beta} signal transduction in human glioblastoma cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dziembowska, Magdalena; Danilkiewicz, Malgorzata; Wesolowska, Aleksandra

2007-03-23

Transforming growth factor-beta (TGF-{beta}) is a multifunctional cytokine involved in the regulation of cell proliferation, differentiation, and survival. Malignant tumour cells often do not respond to TGF-{beta} by growth inhibition, but retain responsiveness to cytokine in regulating extracellular matrix deposition, cell adhesion, and migration. We demonstrated that TGF-{beta}1 does not affect viability or proliferation of human glioblastoma T98G, but increases transcriptional responses exemplified by induction of MMP-9 expression. TGF-{beta} receptors were functional in T98G glioblastoma cells leading to SMAD3/SMAD4 nuclear translocation and activation of SMAD-dependent promoter. In parallel, a selective activation of p38 MAPK, and phosphorylation of its substrates: ATF2more » and c-Jun proteins were followed by a transient activation of AP-1 transcription factor. Surprisingly, an inhibition of p38 MAPK with a specific inhibitor, SB202190, abolished TGF-inducible activation of Smad-dependent promoter and decreased Smad2 phosphorylation. It suggests an unexpected interaction between Smad and p38 MAPK pathways in TGF-{beta}1-induced signalling.« less

Functional Toll-like Receptor 4 Overexpression in Papillary Thyroid Cancer by MAPK/ERK-Induced ETS1 Transcriptional Activity.

PubMed

Peyret, Victoria; Nazar, Magalí; Martín, Mariano; Quintar, Amado A; Fernandez, Elmer A; Geysels, Romina C; Fuziwara, Cesar S; Montesinos, María M; Maldonado, Cristina A; Santisteban, Pilar; Kimura, Edna T; Pellizas, Claudia G; Nicola, Juan P; Masini-Repiso, Ana M

2018-05-01

Emerging evidence suggests that unregulated Toll-like receptor (TLR) signaling promotes tumor survival signals, thus favoring tumor progression. Here, the mechanism underlying TLR4 overexpression in papillary thyroid carcinomas (PTC) mainly harboring the BRAF V600E mutation was studied. TLR4 was overexpressed in PTC compared with nonneoplastic thyroid tissue. Moreover, paired clinical specimens of primary PTC and its lymph node metastasis showed a significant upregulation of TLR4 levels in the metastatic tissues. In agreement, conditional BRAF V600E expression in normal rat thyroid cells and mouse thyroid tissue upregulated TLR4 expression levels. Furthermore, functional TLR4 expression was demonstrated in PTC cells by increased NF-κB transcriptional activity in response to the exogenous TLR4-agonist lipopolysaccharide. Of note, The Cancer Genome Atlas data analysis revealed that BRAF V600E -positive tumors with high TLR4 expression were associated with shorter disease-free survival. Transcriptomic data analysis indicated a positive correlation between TLR4 expression levels and MAPK/ERK signaling activation. Consistently, chemical blockade of MAPK/ERK signaling abrogated BRAF V600E -induced TLR4 expression. A detailed study of the TLR4 promoter revealed a critical MAPK/ERK-sensitive Ets-binding site involved in BRAF V600E responsiveness. Subsequent investigation revealed that the Ets-binding factor ETS1 is critical for BRAF V600E -induced MAPK/ERK signaling-dependent TLR4 gene expression. Together, these data indicate that functional TLR4 overexpression in PTCs is a consequence of thyroid tumor-oncogenic driver dysregulation of MAPK/ERK/ETS1 signaling. Implications: Considering the participation of aberrant NF-κB signaling activation in the promotion of thyroid tumor growth and the association of high TLR4 expression with more aggressive tumors, this study suggests a prooncogenic potential of TLR4 downstream signaling in thyroid tumorigenesis. Mol Cancer Res; 16

AP-1 mediated transcriptional repression of matrix metalloproteinase-9 by recruitment of histone deacetylase 1 in response to interferon β.

PubMed

Mittelstadt, Megan L; Patel, Rekha C

2012-01-01

Matrix metalloproteinase-9 (MMP-9) is a 92 kDa zinc-dependant endopeptidase that degrades components of the extracellular matrix. Increased expression of MMP-9 is implicated in many pathological conditions including metastatic cancer, multiple sclerosis, and atherosclerosis. Although it has been widely noted that interferon-β (IFNβ) downregulates both the basal and phorbol 12-myristate 13-acetate (PMA)-induced MMP-9 expression at the transcriptional level, the molecular mechanism of this repression is poorly understood. In the present study we identify a novel mechanism for repression of MMP-9 transcription by IFNβ in HT1080 fibrosarcoma cells. Using reporter assays with promoter deletion constructs we show that IFNβ's inhibitory effects require a region of the promoter between -154 and -72, which contains an AP-1 binding site. Chromatin immunoprecipitation (ChIP) studies indicate that IFNβ increases histone deacetylase (HDAC)-1 recruitment to the MMP-9 promoter and reduces histone H3 acetylation, in addition to reduced NF-κB recruitment. ChIP analysis shows that IFNβ induced HDAC1 recruitment to the MMP-9 promoter and IFNβ mediated transcriptional repression is lost when the AP-1 binding site is inactivated by a point mutation. Altogether, our results establish that the repression of MMP-9 transcription in response to IFNβ occurs by the recruitment of HDAC1 via the proximal AP-1 binding site.

The tumor promoter arsenite stimulates AP-1 activity by inhibiting a JNK phosphatase.

PubMed Central

Cavigelli, M; Li, W W; Lin, A; Su, B; Yoshioka, K; Karin, M

1996-01-01

Trivalent arsenic (As3+) is highly carcinogenic, but devoid of known mutagenic activity. Therefore, it is likely to act as a tumor promoter. To understand the molecular basis for the tumor-promoting activity of As3+, we examined its effect on transcription factor AP-1, whose activity is stimulated by several other tumor promoters. We found that As3+, but not As5+, which is toxic but not carcinogenic, is a potent stimulator of AP-1 transcriptional activity and an efficient inducer of c-fos and c-jun gene expression. Induction of c-jun and c-fos transcription by As3+ correlates with activation of Jun kinases (JNKs) and p38/Mpk2, which phosphorylate transcription factors that activate these immediate early genes. No effect on ERK activity was observed. As5+, on the other hand, had a negligible effect on JNK or p38/Mpk2 activity. Biochemical analysis and co-transfection experiments strongly suggest that the primary mechanism by which As3+ stimulates JNK activity involves the inhibition of a constitutive dual-specificity JNK phosphatase. This phosphatase activity appears to be responsible for maintaining low basal JNK activity in non-stimulated cells and its inhibition may lead to tumor promotion through induction of proto-oncogenes such as c-jun and c-fos, and stimulation of AP-1 activity. The same phosphatase may also regulate p38/Mpk2 activity. Images PMID:8947050

Macrophages produce IL-33 by activating MAPK signaling pathway during RSV infection.

PubMed

Qi, Feifei; Bai, Song; Wang, Dandan; Xu, Lei; Hu, Haiyan; Zeng, Sheng; Chai, Ruonan; Liu, Beixing

2017-07-01

It has been reported that RSV infection can enhance IL-33 production in lung macrophages. However, little is known about specific signaling pathways for activation of macrophages during RSV infection. In the present study, by using real-time RT-PCR as well as western blot assay, it became clear that RSV infection can enhance not only the expression of mRNAs for MAPK molecules (including p38, JNK1/2, and ERK1/2), but also the levels of MAPK proteins in lung macrophages as well as RAW264.7 cells. Furthermore, infection with RSV resulted in an increased level of phosphorylated MAPK proteins in RAW264.7 cells, suggesting that MAPK signaling pathway may participate in the process of RSV-induced IL-33 secretion by macrophages. In fact, the elevated production of IL-33 in RAW264.7 was attenuated significantly by pretreatment of the cells with special MAPK inhibitor before RSV infection, further confirming the function of MAPKs pathway in RSV-induced IL-33 production in macrophages. In contrast, the expression of NF-κB mRNA as well as the production of NF-κB protein in lung macrophages and RAW264.7 cells was not enhanced markedly after RSV infection. Moreover, RSV infection failed to induce the phosphorylation of NF-κB in RAW264.7 cells, suggesting that NF-κB signaling pathway may be not involved in RSV-induced IL-33 production in macrophages. Conclusion, these results indicate that RSV-induced production of IL-33 in macrophages is dependent on the activation of MAPK signaling pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structural and Dynamic Insights into the Mechanism of Allosteric Signal Transmission in ERK2-Mediated MKP3 Activation.

PubMed

Lu, Chang; Liu, Xin; Zhang, Chen-Song; Gong, Haipeng; Wu, Jia-Wei; Wang, Zhi-Xin

2017-11-21

The mitogen-activated protein kinases (MAPKs) are key components of cellular signal transduction pathways, which are down-regulated by the MAPK phosphatases (MKPs). Catalytic activity of the MKPs is controlled both by their ability to recognize selective MAPKs and by allosteric activation upon binding to MAPK substrates. Here, we use a combination of experimental and computational techniques to elucidate the molecular mechanism for the ERK2-induced MKP3 activation. Mutational and kinetic study shows that the 334 FNFM 337 motif in the MKP3 catalytic domain is essential for MKP3-mediated ERK2 inactivation and is responsible for ERK2-mediated MKP3 activation. The long-term molecular dynamics (MD) simulations further reveal a complete dynamic process in which the catalytic domain of MKP3 gradually changes to a conformation that resembles an active MKP catalytic domain over the time scale of the simulation, providing a direct time-dependent observation of allosteric signal transmission in ERK2-induced MKP3 activation.

A non-Mendelian MAPK-generated hereditary unit controlled by a second MAPK pathway in Podospora anserina.

PubMed

Lalucque, Hervé; Malagnac, Fabienne; Brun, Sylvain; Kicka, Sébastien; Silar, Philippe

2012-06-01

The Podospora anserina PaMpk1 MAP kinase (MAPK) signaling pathway can generate a cytoplasmic and infectious element resembling prions. When present in the cells, this C element causes the crippled growth (CG) cell degeneration. CG results from the inappropriate autocatalytic activation of the PaMpk1 MAPK pathway during growth, whereas this cascade normally signals stationary phase. Little is known about the control of such prion-like hereditary units involved in regulatory inheritance. Here, we show that another MAPK pathway, PaMpk2, is crucial at every stage of the fungus life cycle, in particular those controlled by PaMpk1 during stationary phase, which includes the generation of C. Inactivation of the third P. anserina MAPK pathway, PaMpk3, has no effect on the development of the fungus. Mutants of MAPK, MAPK kinase, and MAPK kinase kinase of the PaMpk2 pathway are unable to present CG. This inability likely relies upon an incorrect activation of PaMpk1, although this MAPK is normally phosphorylated in the mutants. In PaMpk2 null mutants, hyphae are abnormal and PaMpk1 is mislocalized. Correspondingly, stationary phase differentiations controlled by PaMpk1 are defective in the mutants of the PaMpk2 cascade. Constitutive activation of the PaMpk2 pathway mimics in many ways its inactivation, including an effect on PaMpk1 localization. Analysis of double and triple mutants inactivated for two or all three MAPK genes undercover new growth and differentiation phenotypes, suggesting overlapping roles. Our data underscore the complex regulation of a prion-like element in a model organism.

A Non-Mendelian MAPK-Generated Hereditary Unit Controlled by a Second MAPK Pathway in Podospora anserina

PubMed Central

Lalucque, Hervé; Malagnac, Fabienne; Brun, Sylvain; Kicka, Sébastien; Silar, Philippe

2012-01-01

The Podospora anserina PaMpk1 MAP kinase (MAPK) signaling pathway can generate a cytoplasmic and infectious element resembling prions. When present in the cells, this C element causes the crippled growth (CG) cell degeneration. CG results from the inappropriate autocatalytic activation of the PaMpk1 MAPK pathway during growth, whereas this cascade normally signals stationary phase. Little is known about the control of such prion-like hereditary units involved in regulatory inheritance. Here, we show that another MAPK pathway, PaMpk2, is crucial at every stage of the fungus life cycle, in particular those controlled by PaMpk1 during stationary phase, which includes the generation of C. Inactivation of the third P. anserina MAPK pathway, PaMpk3, has no effect on the development of the fungus. Mutants of MAPK, MAPK kinase, and MAPK kinase kinase of the PaMpk2 pathway are unable to present CG. This inability likely relies upon an incorrect activation of PaMpk1, although this MAPK is normally phosphorylated in the mutants. In PaMpk2 null mutants, hyphae are abnormal and PaMpk1 is mislocalized. Correspondingly, stationary phase differentiations controlled by PaMpk1 are defective in the mutants of the PaMpk2 cascade. Constitutive activation of the PaMpk2 pathway mimics in many ways its inactivation, including an effect on PaMpk1 localization. Analysis of double and triple mutants inactivated for two or all three MAPK genes undercover new growth and differentiation phenotypes, suggesting overlapping roles. Our data underscore the complex regulation of a prion-like element in a model organism. PMID:22426880

Interleukin-1 Receptor Activation by Systemic Lipopolysaccharide Induces Behavioral Despair Linked to MAPK Regulation of CNS Serotonin Transporters

PubMed Central

Zhu, Chong-Bin; Lindler, Kathryn M; Owens, Anthony W; Daws, Lynette C; Blakely, Randy D; Hewlett, William A

2010-01-01

Serotonin (5-hydroxytryptamine, 5-HT) has long been implicated in regulation of mood. Medications that block the neuronal 5-HT transporter (SERT) are used as major pharmacological treatment for mood disorders. Conversely, stimuli that enhance SERT activity might be predicted to diminish synaptic 5-HT availability and increase the risk for 5-HT-related CNS disorders. We have shown that the inflammatory cytokines enhance brain SERT activity in cultured serotonergic cells and nerve terminal preparations in vitro. In this study, we establish that intraperitoneal injection of the cytokine-inducer lipopolysaccharide (LPS) stimulates brain SERT activity, acting at doses below those required to induce overt motor suppression. SERT stimulation by LPS is paralleled by increased immobility in both the tail suspension test (TST) and the forced swim test (FST); antidepressant-sensitive alterations are thought to model aspects of behavioral despair. Both the stimulation of SERT activity and induced immobility are absent when LPS is administered to interleukin-1 receptor (IL-1R)-deficient mice and in the presence of SB203580, an inhibitor of IL-1R-stimulated p38 MAPK. Moreover, the ability of LPS to enhance immobility in TST is lost in SERT knockout mice. These findings reveal an ability of peripheral inflammatory stimuli to enhance brain SERT activity through IL-1R and p38 MAPK pathways in vivo and identify a requirement for SERT expression in immune-system-modulated despair behaviors. Our studies identify IL-1R- and p38 MAPK-dependent regulation of SERT as one of the mechanisms by which environmentally driven immune system activation can trigger despair-like behavior in an animal model, encouraging future analysis of the pathway for risk factors in neuropsychiatric disorders. PMID:20827273

Induction of dystrophin Dp71 expression during neuronal differentiation: opposite roles of Sp1 and AP2alpha in Dp71 promoter activity.

PubMed

Morales-Lázaro, Sara Luz; González-Ramírez, Ricardo; Gómez, Pablo; Tapia-Ramírez, Victor; de León, Mario Bermúdez; Cisneros, Bulmaro

2010-01-01

In this study, we delineated the molecular mechanisms that modulate Dp71 expression during neuronal differentiation, using the N1E-115 cell line. We demonstrated that Dp71 expression is up-regulated in response to cAMP-mediated neuronal differentiation of these cells, and that this induction is controlled at promoter level. Functional deletion analysis of the Dp71 promoter revealed that a 5'-flanking 159-bp DNA fragment that contains Sp1 and AP2 binding sites is necessary and sufficient for basal expression of this TATA-less promoter, as well as for its induction during neuronal differentiation. Electrophoretic mobility shift and chromatin immunoprecipitation assays revealed that Sp1 and AP2alpha bind to their respective DNA elements within the Dp71 basal promoter. Overall, mutagenesis assays on the Sp1 and AP2 binding sites, over-expression of Sp1 and AP2alpha, as well as knock-down experiments on Sp1 and AP2alpha gene expression established that Dp71 basal expression is controlled by the combined action of Sp1 and AP2alpha, which act as activator and repressor, respectively. Furthermore, we demonstrated that induction of Dp71 expression in differentiated cells is the result of the maintenance of positive regulation exerted by Sp1, as well as of the loss of AP2alpha binding, which ultimately releases the promoter from repression.

G protein-coupled estrogen receptor 1 (GPER 1) mediates estrogen-induced, proliferation of leiomyoma cells.

PubMed

Jiang, Xiuxiu; Ye, Xiaolei; Ma, Junyan; Li, Wen; Wu, Ruijin; Jun, Lin

2015-01-01

G protein-coupled estrogen receptor 1 (GPER-1, formerly known as GPR30) has been proposed as the receptor for estrogen-induced, growth of leiomyomas though its precise mechanisms of action are not clear. We obtained leiomyoma cells (LC) and normal smooth muscle cells from 28 women (n = 28, median age 38 years, median parity 1.0). We incubated them with 17-β estradiol (E(2)), after blocking, or upregulating, expression of GPER-1 with ICI182,780 (a GPER-1 agonist) and siGPR30, respectively. We evaluated the role of GPER-1 in the mitogen-activated protein kinase (MAPK) signaling pathway using Western blot analysis. We studied cell proliferation with 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide, and, mitotic activity with phosphohistone H3 (PPH3) expression in leiomyoma, and, matched, normal, smooth muscle tissues using standard immunohistochemistry. Downregulation of GPER-1 expression with siGPR30 partially attenuated the E(2)-activated MAPK signaling pathway (p < 0.01). Upregulation of GPER-1 with ICI182,780 enhanced the E(2)-activated MAPK signaling pathway (p < 0.01). ICI182,780 enhanced E(2)-induced proliferation of LC (p < 0.01), while knock down of the GPER-1 gene with GPER-1 small interfering RNA partially inhibited E(2)-induced cell proliferation (p < 0.01). There were no significant differences in PPH3 expression between LCs and normal smooth muscle tissues (p > 0.05). Neither ICI182,780 nor siGPR30 increased mitosis in LCs (p > 0.05). Our results indicate that GPER-1 mediates proliferation of estrogen-induced, LC by activating the MAPK pathway, and, not by promoting mitosis.

The effect of dehydroglyasperin C on UVB-mediated MMPs expression in human HaCaT cells.

PubMed

Xuan, Song Hua; Park, Young Min; Ha, Ji Hoon; Jeong, Yoon Ju; Park, Soo Nam

2017-12-01

The ultraviolet B (UVB) from solar radiation increases the generation of reactive oxygen species (ROS), which mediate the production of matrix metalloproteinases (MMPs), and acts mainly on the epidermis layer of the skin. This study was aimed at assessing the anti-photoaging effects of dehydroglyasperin C isolated from Glycyrrhiza uralensis Fisch on MMPs levels in HaCaT human keratinocytes and to elucidate the underlying mechanism. The cell viability was measured by MTT assay. Expression, phosphorylation and enzymatic activity of the protein were examined using ELISA, Western blot or gelatin zymography. Intracellular ROS measurement was evaluated by fluorescent ELISA and 2',7'-dichlorodihydrofluorescein diacetate (H 2 DCF-DA) assay. In the present study, we found that dehydroglyasperin C markedly inhibited UVB-mediated expression of collagenase (MMP-1) and gelatinase (MMP-9) by inhibiting ROS generation. Dehydroglyasperin C treatment also decreased the UVB irradiation-mediated activation of mitogen-activated protein kinase (MAPK), c-Jun phosphorylation, and c-Fos expression. In addition, the down-regulation of UVB-induced c-Jun phosphorylation caused by dehydroglyasperin C treatment was more than the down-regulation of c-Fos expression in the HaCaT human keratinocytes. Our results indicated that dehydroglyasperin C may function as a potential anti-photoaging agent by inhibiting UVB-mediated MMPs expression via suppression of MAPK and AP-1 signaling. Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Valsartan ameliorates ageing-induced aorta degeneration via angiotensin II type 1 receptor-mediated ERK activity

PubMed Central

Shan, HaiYan; Zhang, Siyang; Li, Xuelian; yu, Kai; Zhao, Xin; Chen, Xinyue; Jin, Bo; Bai, XiaoJuan

2014-01-01

Angiotensin II (Ang II) plays important roles in ageing-related disorders through its type 1 receptor (AT1R). However, the role and underlying mechanisms of AT1R in ageing-related vascular degeneration are not well understood. In this study, 40 ageing rats were randomly divided into two groups: ageing group which received no treatment (ageing control), and valsartan group which took valsartan (selective AT1R blocker) daily for 6 months. 20 young rats were used as adult control. The aorta structure were analysed by histological staining and electron microscopy. Bcl-2/Bax expression in aorta was analysed by immunohistochemical staining, RT-PCR and Western blotting. The expressions of AT1R, AT2R and mitogen-activated protein kinases (MAPKs) were detected. Significant structural degeneration of aorta in the ageing rats was observed, and the degeneration was remarkably ameliorated by long-term administration of valsartan. With ageing, the expression of AT1R was elevated, the ratio of Bcl-2/Bax was decreased and meanwhile, an important subgroup of MAPKs, extracellular signal-regulated kinase (ERK) activity was elevated. However, these changes in ageing rats could be reversed to some extent by valsartan. In vitro experiments observed consistent results as in vivo study. Furthermore, ERK inhibitor could also acquire partial effects as valsartan without affecting AT1R expression. The results indicated that AT1R involved in the ageing-related degeneration of aorta and AT1R-mediated ERK activity was an important mechanism underlying the process. PMID:24548645

Inhibition of benzopyrene diol epoxide-induced apoptosis by cadmium (II) is AP-1-independent: role of extracelluler signal related kinase

PubMed Central

Mukherjee, Jagat J.; Gupta, Suresh K.; Kumar, Subodh

2010-01-01

Cadmium, a major metal constituent of tobacco smoke, elicits synergistic enhancement of cell transformation when combined with benzo[a]pyrene (BP) or other PAHs. The mechanism underlying this synergism is not clearly understood. We observed that (+/−)-anti-benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE), an ultimate carcinogen of BP, induces apoptosis in promotion sensitive mouse epidermal JB6 Cl41 cells at non-cytotoxic concentrations. BPDE also activates AP-1 several folds in AP-1 reporter JB6 cells. Cadmium at non-cytotoxic concentrations inhibits both AP-1 activation and apoptosis in response to BPDE. Since AP-1 is known to be involved in stress-induced apoptosis we investigated whether inhibition of AP-1 by cadmium has any role in the inhibition of BPDE-induced apoptosis. MAP kinases (particularly ERKs, p38 and JNKs) are known to have important role in DNA damage-induced AP-1 activation. We observed that ERK and JNK, but not p38 MAP kinase, are involved in BPDE-induced AP-1 activation. Effect of cadmium on MAP kinases and the effect of inhibition of above three MAP kinases on BPDE-induced AP-1 activation and apoptosis indicate that AP-1 is probably not involved in BPDE-induced apoptosis. Cadmium up-regulates BPDE-activated ERKs and ERK inhibition by U0126 relieves cadmium-mediated inhibition of BPDE-induced apoptosis. We suggest that cadmium inhibits BPDE-induced apoptosis not involving AP-1 but probably through a different mechanism by up-regulating ERK which is known to promote cell survival. PMID:18093576

OSU-DY7, a novel D-tyrosinol derivative, mediates cytotoxicity in chronic lymphocytic leukaemia and Burkitt lymphoma through p38 mitogen-activated protein kinase pathway

PubMed Central

Bai, Li-Yuan; Ma, Yihui; Kulp, Samuel K.; Wang, Shu-Huei; Chiu, Chang-Fang; Frissora, Frank; Mani, Rajeswaran; Mo, Xiaokui; Jarjoura, David; Byrd, John C.; Chen, Ching-Shih; Muthusamy, Natarajan

2013-01-01

Summary Drug resistance and associated immune deregulation limit use of current therapies in chronic lymphocytic leukaemia (CLL), thus warranting alternative therapy development. Herein we demonstrate that OSU-DY7, a novel D-tyrosinol derivative targeting p38 mitogen-activated protein kinase (MAPK), mediates cytotoxicity in lymphocytic cell lines representing CLL (MEC-1), acute lymphoblastic leukaemia (697 cells), Burkitt lymphoma (Raji and Ramos) and primary B cells from CLL patients in a dose- and time-dependent manner. The OSU-DY7-induced cytotoxicity is dependent on caspase activation, as evidenced by induction of caspase-3 activation and poly (ADP-ribose) polymerase (PARP) cleavage and rescue of cytotoxicity by Z-VAD-FMK. Interestingly, OSU-DY7-induced cytotoxicity is mediated through activation of p38 MAPK, as evidenced by increased phosphorylation of p38 MAPK and downstream target protein MAPKAPK2. Pretreatment of B-CLL cells with SB202190, a specific p38 MAPK inhibitor, results in decreased MAPKAPK2 protein level with concomitant rescue of the cells from OSU-DY7-mediated cytotoxicity. Furthermore, OSU-DY7-induced cytotoxicity is associated with down regulation of p38 MAPK target BIRC5, that is rescued at protein and mRNA levels by SB202190. This study provides evidence for a role of OSU-DY7 in p38 MAPK activation and BIRC5 down regulation associated with apoptosis in B lymphocytic cells, thus warranting development of this alternative therapy for lymphoid malignancies. PMID:21470196

The Alternative Epac/cAMP Pathway and the MAPK Pathway Mediate hCG Induction of Leptin in Placental Cells

PubMed Central

Maymó, Julieta Lorena; Pérez Pérez, Antonio; Maskin, Bernardo; Dueñas, José Luis; Calvo, Juan Carlos; Sánchez Margalet, Víctor; Varone, Cecilia Laura

2012-01-01

Pleiotropic effects of leptin have been identified in reproduction and pregnancy, particularly in the placenta, where it works as an autocrine hormone. In this work, we demonstrated that human chorionic gonadotropin (hCG) added to JEG-3 cell line or to placental explants induces endogenous leptin expression. We also found that hCG increased cAMP intracellular levels in BeWo cells in a dose-dependent manner, stimulated cAMP response element (CRE) activity and the cotransfection with an expression plasmid of a dominant negative mutant of CREB caused a significant inhibition of hCG stimulation of leptin promoter activity. These results demonstrate that hCG indeed activates cAMP/PKA pathway, and that this pathway is involved in leptin expression. Nevertheless, we found leptin induction by hCG is dependent on cAMP levels. Treatment with (Bu)2cAMP in combination with low and non stimulatory hCG concentrations led to an increase in leptin expression, whereas stimulatory concentrations showed the opposite effect. We found that specific PKA inhibition by H89 caused a significant increase of hCG leptin induction, suggesting that probably high cAMP levels might inhibit hCG effect. It was found that hCG enhancement of leptin mRNA expression involved the MAPK pathway. In this work, we demonstrated that hCG leptin induction through the MAPK signaling pathway is inhibited by PKA. We observed that ERK1/2 phosphorylation increased when hCG treatment was combined with H89. In view of these results, the involvement of the alternative cAMP/Epac signaling pathway was studied. We observed that a cAMP analogue that specifically activates Epac (CPT-OMe) stimulated leptin expression by hCG. In addition, the overexpression of Epac and Rap1 proteins increased leptin promoter activity and enhanced hCG. In conclusion, we provide evidence suggesting that hCG induction of leptin gene expression in placenta is mediated not only by activation of the MAPK signaling pathway but also by the

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

Mycophenolic acid attenuates tumor necrosis factor-alpha-induced endothelin-1 production in human aortic endothelial cells.

PubMed

Yang, Won Seok; Lee, Joo Mi; Han, Nam Jeong; Kim, Yoon Ji; Chang, Jai Won; Park, Su-Kil

2010-07-01

Atherosclerotic cardiovascular disease is the major cause of morbidity and mortality in solid organ transplant recipients. Endothelin-1 (ET-1) is implicated in the pathogenesis of atherosclerosis and is one of the potential therapeutic targets. This study was conducted to evaluate the effect of mycophenolic acid (MPA), an immunosuppressant for the transplant recipients, on tumor necrosis factor-alpha (TNF-alpha)-induced ET-1 production in aortic endothelial cells. In cultured human aortic endothelial cells, TNF-alpha increased ET-1 through AP-1 and NF-kappaB, whereas MPA attenuated it by reducing both AP-1 and NF-kappaB DNA-binding activities. TNF-alpha increased ET-1 via c-Jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK), but not extracellular signal-regulated kinase. N-acetylcysteine that downregulated TNF-alpha-induced reactive oxygen species (ROS) inhibited JNK activation, but not p38 MAPK. N-acetylcysteine, SP600125 (JNK inhibitor) and SB203580 (p38 MAPK inhibitor) attenuated TNF-alpha-induced DNA-binding activities of both AP-1 and NF-kappaB. MPA inhibited JNK and p38 MAPK activations as well as ROS generation. N-acetylcysteine, SP600125, SB203580 and MPA had no effect on either TNF-alpha-induced IkappaBalpha degradation or p65 nuclear translocation, but attenuated p65 Ser276 phosphorylation. MPA attenuated TNF-alpha-induced ET-1 production through inhibitions of ROS-dependent JNK and ROS-independent p38 MAPK that regulated NF-kappaB as well as AP-1. These findings suggest that MPA could have an effect of amelioration of atherosclerosis. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

HIV-1 Nef hijacks clathrin coats by stabilizing AP-1:Arf1 polygons.

PubMed

Shen, Qing-Tao; Ren, Xuefeng; Zhang, Rui; Lee, Il-Hyung; Hurley, James H

2015-10-23

The lentiviruses HIV and simian immunodeficiency virus (SIV) subvert intracellular membrane traffic as part of their replication cycle. The lentiviral Nef protein helps viruses evade innate and adaptive immune defenses by hijacking the adaptor protein 1 (AP-1) and AP-2 clathrin adaptors. We found that HIV-1 Nef and the guanosine triphosphatase Arf1 induced trimerization and activation of AP-1. Here we report the cryo-electron microscopy structures of the Nef- and Arf1-bound AP-1 trimer in the active and inactive states. A central nucleus of three Arf1 molecules organizes the trimers. We combined the open trimer with a known dimer structure and thus predicted a hexagonal assembly with inner and outer faces that bind the membranes and clathrin, respectively. Hexagons were directly visualized and the model validated by reconstituting clathrin cage assembly. Arf1 and Nef thus play interconnected roles in allosteric activation, cargo recruitment, and coat assembly, revealing an unexpectedly intricate organization of the inner AP-1 layer of the clathrin coat. Copyright © 2015, American Association for the Advancement of Science.

Calcium Signaling Is Involved in Cadmium-Induced Neuronal Apoptosis via Induction of Reactive Oxygen Species and Activation of MAPK/mTOR Network

PubMed Central

Luo, Yan; Chen, Zi; Liu, Lei; Zhou, Hongyu; Chen, Wenxing; Shen, Tao; Han, Xiuzhen; Chen, Long; Huang, Shile

2011-01-01

Cadmium (Cd), a toxic environmental contaminant, induces oxidative stress, leading to neurodegenerative disorders. Recently we have demonstrated that Cd induces neuronal apoptosis in part by activation of the mitogen-activated protein kineses (MAPK) and mammalian target of rapamycin (mTOR) pathways. However, the underlying mechanism remains elusive. Here we show that Cd elevated intracellular calcium ion ([Ca2+]i) level in PC12, SH-SY5Y cells and primary murine neurons. BAPTA/AM, an intracellular Ca2+ chelator, abolished Cd-induced [Ca2+]i elevation, and blocked Cd activation of MAKPs including extracellular signal-regulated kinase 1/2 (Erk1/2), c-Jun N-terminal kinase (JNK) and p38, and mTOR-mediated signaling pathways, as well as cell death. Pretreatment with the extracellular Ca2+ chelator EGTA also prevented Cd-induced [Ca2+]i elevation, MAPK/mTOR activation, as well as cell death, suggesting that Cd-induced extracellular Ca2+ influx plays a critical role in contributing to neuronal apoptosis. In addition, calmodulin (CaM) antagonist trifluoperazine (TFP) or silencing CaM attenuated the effects of Cd on MAPK/mTOR activation and cell death. Furthermore, Cd-induced [Ca2+]i elevation or CaM activation resulted in induction of reactive oxygen species (ROS). Pretreatment with BAPTA/AM, EGTA or TFP attenuated Cd-induced ROS and cleavage of caspase-3 in the neuronal cells. Our findings indicate that Cd elevates [Ca2+]i, which induces ROS and activates MAPK and mTOR pathways, leading to neuronal apoptosis. The results suggest that regulation of Cd-disrupted [Ca2+]i homeostasis may be a new strategy for prevention of Cd-induced neurodegenerative diseases. PMID:21544200

Cocoa flavonoids protect hepatic cells against high-glucose-induced oxidative stress: relevance of MAPKs.

PubMed

Cordero-Herrera, Isabel; Martín, María Angeles; Goya, Luis; Ramos, Sonia

2015-04-01

Oxidative stress plays a main role in the pathogenesis of type 2 diabetes mellitus. Cocoa and (-)-epicatechin (EC), a main cocoa flavanol, have been suggested to exert beneficial effects in type 2 diabetes mellitus because of their protective effects against oxidative stress and insulin-like properties. In this study, the protective effect of EC and a cocoa phenolic extract (CPE) against oxidative stress induced by a high-glucose challenge, which causes insulin resistance, was investigated on hepatic HepG2 cells. Oxidative status, phosphorylated mitogen-activated protein kinases (MAPKs), nuclear factor E2 related factor 2 (Nrf2) and p-(Ser)-IRS-1 expression, and glucose uptake were evaluated. EC and CPE regulated antioxidant enzymes and activated extracellular-regulated kinase and Nrf2. EC and CPE pre-treatment prevented high-glucose-induced antioxidant defences and p-MAPKs, and maintained Nrf2 stimulation. The presence of selective MAPK inhibitors induced changes in redox status, glucose uptake, p-(Ser)- and total IRS-1 levels that were observed in CPE-mediated protection. EC and CPE recovered redox status of insulin-resistant HepG2 cells, suggesting that the functionality in EC- and CPE-treated cells was protected against high-glucose-induced oxidative insult. CPE beneficial effects on redox balance and insulin resistance were mediated by targeting MAPKs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

TNF-α stimulates System A amino acid transport in primary human trophoblast cells mediated by p38 MAPK signaling

PubMed Central

Aye, Irving L M H; Jansson, Thomas; Powell, Theresa L

2015-01-01

Maternal obesity and gestational diabetes mellitus (GDM) increase the risk of delivering infants that are large for gestational age with greater adiposity, who are prone to the development of metabolic disease in childhood and beyond. These maternal conditions are also associated with increased levels of the proinflammatory cytokine TNF-α in maternal tissues and the placenta. Recent evidence suggests that changes in placental amino acid transport contribute to altered fetal growth. TNF-α was previously shown to stimulate System A amino acid transport in primary human trophoblasts (PHTs), however the molecular mechanisms remain unknown. In this study, we tested the hypothesis that TNF-α regulates amino acid uptake in cultured PHTs by a mitogen-activated protein kinase (MAPK)-dependent mechanism. Treatment of PHTs with TNF-α significantly increased System A amino acid transport, as well as Erk and p38 MAPK signaling. Pharmacological antagonism of p38, but not Erk MAPK activity, inhibited TNF-α stimulated System A activity. Silencing of p38 MAPK using siRNA transfections prevented TNF-α stimulated System A transport in PHTs. TNF-α significantly increased the protein expression of System A transporters SNAT1 and SNAT2, but did not affect their mRNA expression. The effects of TNF-α on SNAT1 and SNAT2 protein expression were reversed by p38 MAPK siRNA silencing. In conclusion, TNF-α regulates System A activity through increased SNAT1 and SNAT2 transporter protein expression in PHTs. These findings suggest that p38 MAPK may represent a critical mechanistic link between elevated proinflammatory cytokines and increased placental amino acid transport in obese and GDM pregnancies associated with fetal overgrowth. PMID:26508738

Regulation of CCN2/CTGF Expression in the Nucleus Pulposus of the Intervertebral Disc: Role of Smad and AP1 Signaling

PubMed Central

Tran, Cassie M.; Markova, Dessislava; Smith, Harvey E.; Susarla, Bala; Ponnappan, Ravi Kumar; Anderson, D Greg; Symes, Aviva; Shapiro, Irving M.; Risbud, Makarand V.

2011-01-01

Objective To investigate TGFβ regulation of CTGF expression in cells of the nucleus pulposus. Methods Real Time RT-PCR and Western blot analysis was used to measure CTGF expression in the nucleus pulposus. Transfections were used to measure the effect of Smad2/3/7 and AP1on TGFβ mediated CTGF promoter activity. Results CTGF expression was lower in the neonatal disc compared with the skeletally mature rat disc. An increase in CTGF expression and promoter activity was observed in nucleus pulposus cells after TGFβ treatment. Deletion analysis indicated that promoter constructs lacking smad and AP1 motifs were unresponsive to treatment. Analysis showed that full-length Smad3 and the Smad3-MH2 domain alone increased CTGF activity. Further evidence of Smad3 and AP1 involvement was seen when DN-Smad3, SiRNA-Smad3, smad7 and DN-AP1 suppressed TGFβ mediated activation of the CTGF promoter. When either Smad3 or AP1 sites were mutated, CTGF promoter induction by TGFβ was suppressed. We also observed a decrease in expression of CTGF in discs of Smad3 null mice compared to the wild type. Analysis of human nucleus pulposus indicated a trend of increasing CTGF and TGFβ expression in the degenerate state. Conclusion TGFβ, through Smad3 and AP1, serves as a positive regulator of CTGF expression in the nucleus pulposus. We propose that CTGF is a part of the limited reparative response of the degenerate disc. PMID:20222112

Activation of the Jnk signaling pathway by a dual-specificity phosphatase, JSP-1

PubMed Central

Shen, Yu; Luche, Ralf; Wei, Bo; Gordon, Marcia L.; Diltz, Curtis D.; Tonks, Nicholas K.

2001-01-01

The mitogen-activated protein kinases (MAPKs) are integral to the mechanisms by which cells respond to physiological stimuli, such as growth factors, hormones, and cytokines, and to a wide variety of environmental stresses. The MAPKs, which are stimulated by phosphorylation of a TXY motif in their activation loop, are components of signal transduction cascades in which sequential activation of protein kinases culminates in their activation and their subsequent phosphorylation of various effector proteins that mediate the physiological response. MAPKs are also subject to dephosphorylation and inactivation, both by enzymes that recognize the residues of the TXY motif independently and by dual specificity phosphatases, which dephosphroylate both Tyr and Ser/Thr residues. We report the identification and characterization of a novel dual specificity phosphatase. Contrary to expectation, this broadly expressed enzyme did not inactivate MAPKs in transient cotransfection assays but instead displayed the capacity to function as a selective activator of the MAPK Jnk, hence the name, Jnk Stimulatory Phosphatase-1 (JSP-1). This study illustrates a new aspect of the regulation of MAPK-dependent signal transduction and raises the possibility that JSP-1 may offer a different perspective to the study of various inflammatory and proliferative disorders associated with dysfunctional Jnk signaling. PMID:11717427

Activation of the Jnk signaling pathway by a dual-specificity phosphatase, JSP-1.

PubMed

Shen, Y; Luche, R; Wei, B; Gordon, M L; Diltz, C D; Tonks, N K

2001-11-20

The mitogen-activated protein kinases (MAPKs) are integral to the mechanisms by which cells respond to physiological stimuli, such as growth factors, hormones, and cytokines, and to a wide variety of environmental stresses. The MAPKs, which are stimulated by phosphorylation of a TXY motif in their activation loop, are components of signal transduction cascades in which sequential activation of protein kinases culminates in their activation and their subsequent phosphorylation of various effector proteins that mediate the physiological response. MAPKs are also subject to dephosphorylation and inactivation, both by enzymes that recognize the residues of the TXY motif independently and by dual specificity phosphatases, which dephosphroylate both Tyr and Ser/Thr residues. We report the identification and characterization of a novel dual specificity phosphatase. Contrary to expectation, this broadly expressed enzyme did not inactivate MAPKs in transient cotransfection assays but instead displayed the capacity to function as a selective activator of the MAPK Jnk, hence the name, Jnk Stimulatory Phosphatase-1 (JSP-1). This study illustrates a new aspect of the regulation of MAPK-dependent signal transduction and raises the possibility that JSP-1 may offer a different perspective to the study of various inflammatory and proliferative disorders associated with dysfunctional Jnk signaling.

Rottlerin enhances IL-1β-induced COX-2 expression through sustained p38 MAPK activation in MDA-MB-231 human breast cancer cells

PubMed Central

Park, Eun Jung

2011-01-01

Cyclooxygenase-2 (COX-2) is an important enzyme in inflammation. In this study, we investigated the underlying molecular mechanism of the synergistic effect of rottlerin on interleukin1β (IL-1β)-induced COX-2 expression in MDA-MB-231 human breast cancer cell line. Treatment with rottlerin enhanced IL-1β-induced COX-2 expression at both the protein and mRNA levels. Combined treatment with rottlerin and IL-1β significantly induced COX-2 expression, at least in part, through the enhancement of COX-2 mRNA stability. In addition, rottlerin and IL-1β treatment drove sustained activation of p38 Mitogen-activated protein kinase (MAPK), which is involved in induced COX-2 expression. Also, a pharmacological inhibitor of p38 MAPK (SB 203580) and transient transfection with inactive p38 MAPK inhibited rottlerin and IL-1β-induced COX-2 upregulation. However, suppression of protein kinase C δ (PKC δ) expression by siRNA or overexpression of dominant-negative PKC δ (DN-PKC-δ) did not abrogate the rottlerin plus IL-1β-induced COX-2 expression. Furthermore, rottlerin also enhanced tumor necrosis factor-α (TNF-α), phorbol myristate acetate (PMA), and lipopolysaccharide (LPS)-induced COX-2 expression. Taken together, our results suggest that rottlerin causes IL-1β-induced COX-2 upregulation through sustained p38 MAPK activation in MDA-MB-231 human breast cancer cells. PMID:21971413

Effect of OPC-12759 on EGF receptor activation, p44/p42 MAPK activity, and secretion in conjunctival goblet cells.

PubMed

Ríos, J David; Shatos, Marie A; Urashima, Hiroki; Dartt, Darlene A