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Sample records for activates mapk signaling

  1. Quercitrin attenuates osteoporosis in ovariectomized rats by regulating mitogen-activated protein kinase (MAPK) signaling pathways.

    PubMed

    Xing, Li-Zhi; Ni, Huai-Jun; Wang, Yu-Ling

    2017-03-13

    MAPK signaling pathways are crucial in regulating osteogenesis, a genetic disorder affecting the bones. Quercitrin, a type of flavonoid, is widely distributed in nature and involved in many pharmacological activities. But its osteoprotective functions and mechanism in osteoporosis are far from being understood clearly. In this paper, the MAPK upregulation was observed in the ovariectomy-induced bone loss. Quercitrin was found to downregulate MAPK signaling pathways and prevent the ovariectomy-induced deterioration of bone mineral density (BMD), trabecular microstructure, and bone mechanical characteristics. In this study, quercitrin was seen to prevent the progression of the postmenopausal osteoporosis among the rats, which may be mediated by the downregulated MAPK signaling pathways.

  2. Calcium signaling and the MAPK cascade are required for sperm activation in Caenorhabditis elegans.

    PubMed

    Liu, Zhiyu; Wang, Bin; He, Ruijun; Zhao, Yanmei; Miao, Long

    2014-02-01

    In nematode, sperm activation (or spermiogenesis), a process in which the symmetric and non-motile spermatids transform into polarized and crawling spermatozoa, is critical for sperm cells to acquire fertilizing competence. SPE-8 dependent and SPE-8 independent pathways function redundantly during sperm activation in both males and hermaphrodites of Caenorhabditis elegans. However, the downstream signaling for both pathways remains unclear. Here we show that calcium signaling and the MAPK cascade are required for both SPE-8 dependent and SPE-8 independent sperm activation, implying that both pathways share common downstream signaling components during sperm activation. We demonstrate that activation of the MAPK cascade is sufficient to activate spermatids derived from either wild-type or spe-8 group mutant males and that activation of the MAPK cascade bypasses the requirement of calcium signal to induce sperm activation, indicating that the MAPK cascade functions downstream of or parallel with the calcium signaling during sperm activation. Interestingly, the persistent activation of MAPK in activated spermatozoa inhibits Major Sperm Protein (MSP)-based cytoskeleton dynamics. We demonstrate that MAPK plays dual roles in promoting pseudopod extension during sperm activation but also blocking the MSP-based, amoeboid motility of the spermatozoa. Thus, though nematode sperm are crawling cells, morphologically distinct from flagellated sperm, and the molecular machinery for motility of amoeboid and flagellated sperm is different, both types of sperm might utilize conserved signaling pathways to modulate sperm maturation.

  3. Canonical and alternative MAPK signaling.

    PubMed

    Pimienta, Genaro; Pascual, Jaime

    2007-11-01

    The archetype of MAPK cascade activation is somewhat challenged by the most recent discovery of unexpected phosphorylation patterns, alternative activation mechanisms and sub-cellular localization, in various members of this protein kinase family. In particular, activation by autophosphorylation pathways has now been described for the three best understood MAPK subgroups: ERK1/2; JNK1/2 and p38 alpha/beta. Also, a form of dosage compensation between homologs has been shown to occur in the case of ERK1/2 and JNK1/2. In this paper we summarize the MAPK activation pathway, with an emphasis on non-canonical examples. We use this information to propose a model for MAPK signal transduction that considers a cross-talk between MAPKs with different activation loop sequence motifs and unique C-terminal extensions. We highlight the occurrence of non-canonical substrate specificity during MAPK auto-activation, in strong connection with MAPK homo- and hetero-dimerization events.

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

    PubMed

    Sun, Jing; Nan, Guangxian

    2016-05-01

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

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

    PubMed

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

    2016-04-01

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

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

    PubMed Central

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

    2013-01-01

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

  7. Resveratrol and estradiol rapidly activate MAPK signaling through estrogen receptors alpha and beta in endothelial cells.

    PubMed

    Klinge, Carolyn M; Blankenship, Kristy A; Risinger, Kelly E; Bhatnagar, Shephali; Noisin, Edouard L; Sumanasekera, Wasana K; Zhao, Lei; Brey, Darren M; Keynton, Robert S

    2005-03-04

    Vascular endothelial cells (EC) are an important target of estrogen action through both the classical genomic (i.e. nuclear-initiated) activities of estrogen receptors alpha and beta (ERalpha and ERbeta) and the rapid "non-genomic" (i.e. membrane-initiated) activation of ER that stimulates intracellular phosphorylation pathways. We tested the hypothesis that the red wine polyphenol trans-resveratrol activates MAPK signaling via rapid ER activation in bovine aortic EC, human umbilical vein EC, and human microvascular EC. We report that bovine aortic EC, human umbilical vein EC, and human microvascular EC express ERalpha and ERbeta. We demonstrate that resveratrol and estradiol (E(2)) rapidly activated MAPK in a MEK-1, Src, matrix metalloproteinase, and epidermal growth factor receptor-dependent manner. Importantly, resveratrol activated MAPK and endothelial nitric-oxide synthase (eNOS) at nm concentrations (i.e. an order of magnitude less than that required for ER genomic activity) and concentrations possibly achieved transiently in serum following oral red wine consumption. Co-treatment with ER antagonists ICI 182,780 or 4-hydroxytamoxifen blocked resveratrol- or E(2)-induced MAPK and eNOS activation, indicating ER dependence. We demonstrate for the first time that ERalpha-and ERbeta-selective agonists propylpyrazole triol and diarylpropionitrile, respectively, stimulate MAPK and eNOS activity. A red but not a white wine extract also activated MAPK, and activity was directly correlated with the resveratrol concentration. These data suggest that ER may play a role in the rapid effects of resveratrol in EC and that some of the atheroprotective effects of resveratrol may be mediated through rapid activation of ER signaling in EC.

  8. MAPKs in development: insights from Dictyostelium signaling pathways

    PubMed Central

    Hadwiger, Jeffrey A.; Nguyen, Hoai-Nghia

    2011-01-01

    Mitogen activated protein kinases (MAPKs) play important roles in the development of eukaryotic organisms through the regulation of signal transduction pathways stimulated by external signals. MAPK signaling pathways have been associated with the regulation of cell growth, differentiation, and chemotaxis, indicating MAPKs contribute to a diverse set of developmental processes. In most eukaryotes, the diversity of external signals is likely to far exceed the diversity of MAPKs, suggesting that multiple signaling pathways might share MAPKs. Do different signaling pathways converge before MAPK function or can MAPKs maintain signaling specificity through interactions with specific proteins? The genetic and biochemical analysis of MAPK pathways in simple eukaryotes such as Dictyostelium offers opportunities to investigate functional specificity of MAPKs in G protein-mediated signal transduction pathways. This review considers the regulation and specificity of MAPK function in pathways that control Dictyostelium growth and development. PMID:21666837

  9. Activation of MAPK/ERK signaling by Burkholderia pseudomallei cycle inhibiting factor (Cif)

    PubMed Central

    Ng, Mei Ying; Wang, Mei; Casey, Patrick J.; Gan, Yunn-Hwen; Hagen, Thilo

    2017-01-01

    Cycle inhibiting factors (Cifs) are virulence proteins secreted by the type III secretion system of some Gram-negative pathogenic bacteria including Burkholderia pseudomallei. Cif is known to function to deamidate Nedd8, leading to inhibition of Cullin E3 ubiquitin ligases (CRL) and consequently induction of cell cycle arrest. Here we show that Cif can function as a potent activator of MAPK/ERK signaling without significant activation of other signaling pathways downstream of receptor tyrosine kinases. Importantly, we found that the ability of Cif to activate ERK is dependent on its deamidase activity, but independent of Cullin E3 ligase inhibition. This suggests that apart from Nedd8, other cellular targets of Cif-dependent deamidation exist. We provide evidence that the mechanism involved in Cif-mediated ERK activation is dependent on recruitment of the Grb2-SOS1 complex to the plasma membrane. Further investigation revealed that Cif appears to modify the phosphorylation status of SOS1 in a region containing the CDC25-H and proline-rich domains. It is known that prolonged Cullin E3 ligase inhibition leads to cellular apoptosis. Therefore, we hypothesize that ERK activation is an important mechanism to counter the pro-apoptotic effects of Cif. Indeed, we show that Cif dependent ERK activation promotes phosphorylation of the proapoptotic protein Bim, thereby potentially conferring a pro-survival signal. In summary, we identified a novel deamidation-dependent mechanism of action of the B. pseudomallei virulence factor Cif/CHBP to activate MAPK/ERK signaling. Our study demonstrates that bacterial proteins such as Cif can serve as useful molecular tools to uncover novel aspects of mammalian signaling pathways. PMID:28166272

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2015-06-22

    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.

  12. 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.

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

    PubMed

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

    2016-07-01

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

  14. Baicalin positively regulates osteoclast function by activating MAPK/Mitf signalling.

    PubMed

    Lu, Li; Rao, Li; Jia, Huanhuan; Chen, Jun; Lu, Xingyan; Yang, Guozhu; Li, Qingnan; Lee, Kenneth Ka Ho; Yang, Li

    2017-02-03

    Activation of osteoblasts in bone formation and osteoclasts in bone resorption is important during the bone fracture healing process. There has been a long interest in identifying and developing a natural therapy for bone fracture healing. In this study, we investigated the regulation of osteoclast differentiation by baicalin, which is a natural molecule extracted from Eucommiaulmoides (small tree native to China). It was determined that baicalin enhanced osteoclast maturation and bone resorption activity in a dose-dependent manner. Moreover, this involves the activation of MAPK, increased Mitf nuclear translocation and up-regulation of downstream osteoclast-related target genes expression. The baicalin-induced effect on osteoclast differentiation can be mimicked by specific inhibitors of p-ERK (U0126) and the Mitf-specific siRNA, respectively. Protein-ligand docking prediction identified that baicalin might bind to RANK, which is the upstream receptor of p-ERK/Mitf signalling in osteoclasts. This indicated that RANK might be the binding target of baicalin. In sum, our findings revealed baicalin increased osteoclast maturation and function via p-ERK/Mitf signalling. In addition, the results suggest that baicalin can potentially be used as a natural product for the treatment of bone fracture.

  15. Adiporedoxin suppresses endothelial activation via inhibiting MAPK and NF-κB signaling

    PubMed Central

    He, Hui; Guo, Fang; Li, Yong; Saaoud, Fatma; Kimmis, Brooks D.; Sandhu, Jeena; Fan, Michelle; Maulik, Dev; Lessner, Susan; Papasian, Christopher J.; Fan, Daping; Jiang, Zhisheng; Fu, Mingui

    2016-01-01

    Adiporedoxin (Adrx) is a recently discovered redox regulatory protein that is preferentially expressed in adipose tissue and plays a critical role in the regulation of metabolism via its modulation of adipocyte protein secretion. We here report that Adrx suppresses endothelial cell activation via inhibiting MAPK and NF-kB signaling pathways. Adrx is constitutively expressed in human vascular endothelial cells, and significantly induced by a variety of stimuli such as TNFα, IL-1β, H2O2 and OxLDL. Overexpression of Adrx significantly attenuated TNFα-induced expression of VCAM-1 and ICAM-1, and thus reduced monocyte adherence to human umbilical vein endothelial cells (HUVECs). Conversely, siRNA-mediated knockdown of Adrx increased TNFα-induced expression of adhesion molecules and monocyte adherence to HUVECs. Furthermore, forced expression of Adrx decreased TNFα-induced activation of ERK1/2, JNK, p38 and IKKs in HUVECs. Adrx mutant in the CXXC motif that lost its anti-redox activity is less efficient than the wild-type Adrx, suggesting that Adrx-mediated inhibition of endothelial activation is partially dependent on its antioxidant activity. Finally, Adrx expression was markedly increased in human atheroma compared with normal tissue from the same carotid arteries. These results suggest that Adrx is an endogenous inhibitor of endothelial activation, and might be a therapeutic target for vascular inflammatory diseases. PMID:27941911

  16. CpG- and LPS-activated MAPK signaling in in vitro cultured salmon (Salmo salar) mononuclear phagocytes.

    PubMed

    Iliev, Dimitar B; Hansen, Tom; Jørgensen, Sven Martin; Krasnov, Aleksei; Jørgensen, Jorunn B

    2013-10-01

    The Mitogen-activated protein kinases (MAPK) are involved in transmitting intracellular signals downstream of diverse cell surface receptors and mediate the response to ligands such as growth factors, hormones and cytokines. In addition, MAPK are critically involved in the innate immune response to pathogen-derived substances, commonly referred to as pathogen-associated molecular patterns (PAMPs), such as bacterial lipopolysaccharide (LPS) and bacterial DNA rich in CpG dinucleotides. Currently, a great deal of knowledge is available about the involvement of MAPK in the innate immune response to PAMPs in mammals; however, little is known about the role of the different MAPK classes in the immune response to PAMPs in lower vertebrates. In the current study, p38 phosphorylation was induced by CpG oligonucleotides (ODNs) and LPS in primary salmon mononuclear phagocytes. Pre-treatment of the cells with a p38 inhibitor (SB203580) blocked the PAMP-induced p38 activity and suppressed the upregulation of most of the CpG- and LPS-induced transcripts highlighting the role of this kinase in the salmon innate immune response to PAMPs. In contrast to p38, the phosphorylation of extracellular signal-regulated kinase (ERK), a MAPK involved primarily in response to mitogens, was high in resting cells and, surprisingly, incubation with both CpG and control ODNs downregulated the phospho-ERK levels independently of p38 activation. The basal phospho-ERK level and the CpG-inducible p38 phosphorylation were greatly influenced by the length of in vitro incubation. The basal phospho-ERK level increased gradually throughout a 5-day culture period and was PI3K-dependent as demonstrated by its sensitivity to Wortmannin suggesting it is influenced by growth factors. Overall these data indicate that both basal and PAMP-induced activity of MAPKs might be greatly influenced by the differentiation status of salmon mononuclear phagocytes.

  17. Fasting potentiates the anticancer activity of tyrosine kinase inhibitors by strengthening MAPK signaling inhibition

    PubMed Central

    Caffa, Irene; D'Agostino, Vito; Damonte, Patrizia; Soncini, Debora; Cea, Michele; Monacelli, Fiammetta; Odetti, Patrizio; Ballestrero, Alberto; Provenzani, Alessandro; Longo, Valter D.; Nencioni, Alessio

    2015-01-01

    Tyrosine kinase inhibitors (TKIs) are now the mainstay of treatment in many types of cancer. However, their benefit is frequently short-lived, mandating the search for safe potentiation strategies. Cycles of fasting enhance the activity of chemo-radiotherapy in preclinical cancer models and dietary approaches based on fasting are currently explored in clinical trials. Whether combining fasting with TKIs is going to be potentially beneficial remains unknown. Here we report that starvation conditions increase the ability of commonly administered TKIs, including erlotinib, gefitinib, lapatinib, crizotinib and regorafenib, to block cancer cell growth, to inhibit the mitogen-activated protein kinase (MAPK) signaling pathway and to strengthen E2F-dependent transcription inhibition. In cancer xenografts models, both TKIs and cycles of fasting slowed tumor growth, but, when combined, these interventions were significantly more effective than either type of treatment alone. In conclusion, cycles of fasting or of specifically designed fasting-mimicking diets should be evaluated in clinical studies as a means to potentiate the activity of TKIs in clinical use. PMID:25909220

  18. Fasting potentiates the anticancer activity of tyrosine kinase inhibitors by strengthening MAPK signaling inhibition.

    PubMed

    Caffa, Irene; D'Agostino, Vito; Damonte, Patrizia; Soncini, Debora; Cea, Michele; Monacelli, Fiammetta; Odetti, Patrizio; Ballestrero, Alberto; Provenzani, Alessandro; Longo, Valter D; Nencioni, Alessio

    2015-05-20

    Tyrosine kinase inhibitors (TKIs) are now the mainstay of treatment in many types of cancer. However, their benefit is frequently short-lived, mandating the search for safe potentiation strategies. Cycles of fasting enhance the activity of chemo-radiotherapy in preclinical cancer models and dietary approaches based on fasting are currently explored in clinical trials. Whether combining fasting with TKIs is going to be potentially beneficial remains unknown. Here we report that starvation conditions increase the ability of commonly administered TKIs, including erlotinib, gefitinib, lapatinib, crizotinib and regorafenib, to block cancer cell growth, to inhibit the mitogen-activated protein kinase (MAPK) signaling pathway and to strengthen E2F-dependent transcription inhibition. In cancer xenografts models, both TKIs and cycles of fasting slowed tumor growth, but, when combined, these interventions were significantly more effective than either type of treatment alone. In conclusion, cycles of fasting or of specifically designed fasting-mimicking diets should be evaluated in clinical studies as a means to potentiate the activity of TKIs in clinical use.

  19. YES oncogenic activity is specified by its SH4 domain and regulates RAS/MAPK signaling in colon carcinoma cells

    PubMed Central

    Dubois, Fanny; Leroy, Cédric; Simon, Valérie; Benistant, Christine; Roche, Serge

    2015-01-01

    Members of the SRC family of tyrosine kinases (SFK) display important functions in human cancer, but their specific role in tumorigenesis remains unclear. We previously demonstrated that YES regulates a unique oncogenic signaling important for colorectal cancer (CRC) progression that is not shared with SRC. Here, we addressed the underlying mechanism involved in this process. We show that YES oncogenic signaling relies on palmitoylation of its SH4 domain that controls YES localization in cholesterol-enriched membrane micro-domains. Specifically, deletion of the palmitoylation site compromised YES transforming activity, while addition of a palmitoylation site in the SH4 domain of SRC was sufficient for SRC to restore the transforming properties of cells in which YES had been silenced. Subsequently, SILAC phosphoproteomic analysis revealed that micro-domain-associated cell adhesive components and receptor tyrosine kinases are major YES substrates. YES also phosphorylates upstream regulators of RAS/MAPK signaling, including EGFR, SHC and SHP2, which were not targeted by SRC due to the absence of palmitoylation. Accordingly, EGFR-induced MAPK activity was attenuated by YES down-regulation, while increased RAS activity significantly restored cell transformation that was lost upon YES silencing. Collectively, these results uncover a critical role for the SH4 domain in the specification of SFK oncogenic activity and a selective role for YES in the induction of RAS/MAPK signaling in CRC cells. PMID:26269757

  20. YES oncogenic activity is specified by its SH4 domain and regulates RAS/MAPK signaling in colon carcinoma cells.

    PubMed

    Dubois, Fanny; Leroy, Cédric; Simon, Valérie; Benistant, Christine; Roche, Serge

    2015-01-01

    Members of the SRC family of tyrosine kinases (SFK) display important functions in human cancer, but their specific role in tumorigenesis remains unclear. We previously demonstrated that YES regulates a unique oncogenic signaling important for colorectal cancer (CRC) progression that is not shared with SRC. Here, we addressed the underlying mechanism involved in this process. We show that YES oncogenic signaling relies on palmitoylation of its SH4 domain that controls YES localization in cholesterol-enriched membrane micro-domains. Specifically, deletion of the palmitoylation site compromised YES transforming activity, while addition of a palmitoylation site in the SH4 domain of SRC was sufficient for SRC to restore the transforming properties of cells in which YES had been silenced. Subsequently, SILAC phosphoproteomic analysis revealed that micro-domain-associated cell adhesive components and receptor tyrosine kinases are major YES substrates. YES also phosphorylates upstream regulators of RAS/MAPK signaling, including EGFR, SHC and SHP2, which were not targeted by SRC due to the absence of palmitoylation. Accordingly, EGFR-induced MAPK activity was attenuated by YES down-regulation, while increased RAS activity significantly restored cell transformation that was lost upon YES silencing. Collectively, these results uncover a critical role for the SH4 domain in the specification of SFK oncogenic activity and a selective role for YES in the induction of RAS/MAPK signaling in CRC cells.

  1. Discoidin domain receptor 1 promotes Th17 cell migration by activating the RhoA/ROCK/MAPK/ERK signaling pathway

    PubMed Central

    Azreq, Mohammed-Amine El; Kadiri, Maleck; Boisvert, Marc; Pagé, Nathalie; Tessier, Philippe A.; Aoudjit, Fawzi

    2016-01-01

    Effector T cell migration through the tissue extracellular matrix (ECM) is an important step of the adaptive immune response and in the development of inflammatory diseases. However, the mechanisms involved in this process are still poorly understood. In this study, we addressed the role of a collagen receptor, the discoidin domain receptor 1 (DDR1), in the migration of Th17 cells. We showed that the vast majority of human Th17 cells express DDR1 and that silencing DDR1 or using the blocking recombinant receptor DDR1:Fc significantly reduced their motility and invasion in three-dimensional (3D) collagen. DDR1 promoted Th17 migration by activating RhoA/ROCK and MAPK/ERK signaling pathways. Interestingly, the RhoA/ROCK signaling module was required for MAPK/ERK activation. Finally, we showed that DDR1 is important for the recruitment of Th17 cells into the mouse dorsal air pouch containing the chemoattractant CCL20. Collectively, our results indicate that DDR1, via the activation of RhoA/ROCK/MAPK/ERK signaling axis, is a key pathway of effector T cell migration through collagen of perivascular tissues. As such, DDR1 can contribute to the development of Th17-dependent inflammatory diseases. PMID:27391444

  2. Bridelia ferruginea Produces Antineuroinflammatory Activity through Inhibition of Nuclear Factor-kappa B and p38 MAPK Signalling

    PubMed Central

    Olajide, Olumayokun A.; Aderogba, Mutalib A.; Okorji, Uchechukwu P.; Fiebich, Bernd L.

    2012-01-01

    Bridelia ferruginea is commonly used in traditional African medicine (TAM) for treating various inflammatory conditions. Extracts from the plant have been shown to exhibit anti-inflammatory property in a number of in vivo models. In this study the influence of B. ferruginea (BFE) on the production of PGE2, nitrite, and proinflammatory cytokines from LPS-stimulated BV-2 microglia was investigated. The effects of BFE on cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) protein expressions were evaluated in LPS-activated rat primary microglia. The roles of NF-κB and MAPK signalling in the actions of BFE were also investigated. BFE (25–200 μg) inhibited the production of PGE2, nitrite, tumour necrosis factor-α (TNFα), and interleukin-6 (IL-6) as well as COX-2 and iNOS protein expressions in LPS-activated microglial cells. Further studies to elucidate the mechanism of anti-inflammatory action of BFE revealed interference with nuclear translocation of NF-κBp65 through mechanisms involving inhibition of IκB degradation. BFE prevented phosphorylation of p38, but not p42/44 or JNK MAPK. It is suggested that Bridelia ferruginea produces anti-inflammatory action through mechanisms involving p38 MAPK and NF-κB signalling. PMID:23320030

  3. MAPK Assays in Arabidopsis MAMP-PRR Signal Transduction.

    PubMed

    Chung, Hoo Sun; Sheen, Jen

    2017-01-01

    Activation of MAPK (Mitogen-Activated Protein Kinase) cascades after MAMP (Microbe-Associated Molecular Pattern) perception through PRR (Pattern Recognition Receptor) is one of the first conserved responses when plants encounter microbial organisms. Phosphorylation of various cellular factors in the MAMP-PRR pathway by MAPK cascades is critical for broad-spectrum plant innate immunity. Measurement of MAPK activation and identification of MAPK phosphorylation targets in the MAMP-PRR signal transduction pathway are essential to understand how plants reprogram their cellular processes to cope with unfavorable microbial attack. Here, we describe detailed protocols of three assays measuring MAPK activity after MAMP perception: (1) immune-blotting analysis with anti-phospho ERK1/2 antibody; (2) in-gel kinase assay using a general substrate myelin basic protein (MBP); (3) an in vitro kinase assay to evaluate phosphorylation of MAPK substrate candidates during MAMP-PRR signaling based on a protoplast expression system.

  4. BDE-47 induces oxidative stress, activates MAPK signaling pathway, and elevates de novo lipogenesis in the copepod Paracyclopina nana.

    PubMed

    Lee, Min-Chul; Puthumana, Jayesh; Lee, Seung-Hwi; Kang, Hye-Min; Park, Jun Chul; Jeong, Chang-Bum; Han, Jeonghoon; Hwang, Dae-Sik; Seo, Jung Soo; Park, Heum Gi; Om, Ae-Son; Lee, Jae-Seong

    2016-12-01

    Brominated flame retardant, 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47), has received grave concerns as a persistent organic pollutant, which is toxic to marine organisms, and a suspected link to endocrine abnormalities. Despite the wide distribution in the marine ecosystem, very little is known about the toxic impairments on marine organisms, particularly on invertebrates. Thus, we examined the adverse effects of BDE-47 on life history trait (development), oxidative markers, fatty acid composition, and lipid accumulation in response to BDE-47-induced stress in the marine copepod Paracyclopina nana. Also, activation level of mitogen-activated protein kinase (MAPK) signaling pathways along with the gene expression profile of de novo lipogenesis (DNL) pathways were addressed. As a result, BDE-47 induced oxidative stress (e.g. reactive oxygen species, ROS) mediated activation of extracellular signal-regulated kinase (ERK) and c-Jun-N-terminal kinase (JNK) signaling cascades in MAPK pathways. Activated MAPK pathways, in turn, induced signal molecules that bind to the transcription factors (TFs) responsible for lipogenesis to EcR, SREBP, ChREBP promoters. Also, the stress stimulated the conversion of saturated fatty acids (SFAs) to polyunsaturated fatty acids (PUFAs), a preparedness of the organism to adapt the observed stress, which could be correlated with the elongase and desaturase gene (e.g. ELO3, Δ5-DES, Δ9-DES) expressions, and then extended to the delayed early post-embryonic development and increased accumulation of lipid droplets in P. nana. This study will provide a better understanding of how BDE-47 effects on marine invertebrates particularly on the copepods, an important link in the marine food chain.

  5. Adverse effects of MWCNTs on life parameters, antioxidant systems, and activation of MAPK signaling pathways in the copepod Paracyclopina nana.

    PubMed

    Kim, Duck-Hyun; Puthumana, Jayesh; Kang, Hye-Min; Lee, Min-Chul; Jeong, Chang-Bum; Han, Jeonghoon; Hwang, Dae-Sik; Kim, Il-Chan; Lee, Jin Wuk; Lee, Jae-Seong

    2016-10-01

    Engineered multi-walled carbon nanotubes (MWCNTs) have received widespread applications in a broad variety of commercial products due to low production cost. Despite their significant commercial applications, CNTs are being discharged to aquatic ecosystem, leading a threat to aquatic life. Thus, we investigated the adverse effect of CNTs on the marine copepod Paracyclopina nana. Additional to the study on the uptake of CNTs and acute toxicity, adverse effects on life parameters (e.g. growth, fecundity, and size) were analyzed in response to various concentrations of CNTs. Also, as a measurement of cellular damage, oxidative stress-related markers were examined in a time-dependent manner. Moreover, activation of redox-sensitive mitogen-activated protein kinase (MAPK) signaling pathways along with the phosphorylation pattern of extracellular signal-regulated kinase (ERK), p38, and c-Jun-N-terminal kinases (JNK) were analyzed to obtain a better understanding of molecular mechanism of oxidative stress-induced toxicity in the copepod P. nana. As a result, significant inhibition on life parameters and evoked antioxidant systems were observed without ROS induction. In addition, CNTs activated MAPK signaling pathway via ERK, suggesting that phosphorylated ERK (p-ERK)-mediated adverse effects are the primary cause of in vitro and in vivo endpoints in response to CNTs exposure. Moreover, ROS-independent activation of MAPK signaling pathway was observed. These findings will provide a better understanding of the mode of action of CNTs on the copepod P. nana at cellular and molecular level and insight on possible ecotoxicological implications in the marine environment.

  6. Inhibition of aldehyde dehydrogenase 2 activity enhances antimycin-induced rat cardiomyocytes apoptosis through activation of MAPK signaling pathway.

    PubMed

    Zhang, Peng; Xu, Danling; Wang, Shijun; Fu, Han; Wang, Keqiang; Zou, Yunzeng; Sun, Aijun; Ge, Junbo

    2011-12-01

    Aldehyde dehydrogenase 2 (ALDH2), a mitochondrial-specific enzyme, has been proved to be involved in oxidative stress-induced cell apoptosis, while little is known in cardiomyocytes. This study was aimed at investigating the role of ALDH2 in antimycin A-induced cardiomyocytes apoptosis by suppressing ALDH2 activity with a specific ALDH2 inhibitor Daidzin. Antimycin A (40μg/ml) was used to induce neonatal cardiomyocytes apoptosis. Daidzin (60μM) effectively inhibited ALDH2 activity by 50% without own effect on cell apoptosis, and significantly enhanced antimycin A-induced cardiomyocytes apoptosis from 33.5±4.4 to 56.5±6.4% (Hochest method, p<0.05), and from 57.9±1.9 to 74.0±11.9% (FACS, p<0.05). Phosphorylation of activated MAPK signaling pathway, including extracellular signal-regulated kinase (ERK1/2), c-Jun NH2-terminal kinase (JNK) and p38 was also increased in antimycin A and daidzin treated cardiomyocytes compared to the cells treated with antimycin A alone. These findings indicated that modifying mitochondrial ALDH2 activity/expression might be a potential therapeutic option on reducing oxidative insults induced cardiomyocytes apoptosis.

  7. Obox4-silencing-activated STAT3 and MPF/MAPK signaling accelerate nuclear membrane breakdown in mouse oocytes.

    PubMed

    Lee, Hyun-Seo; Kim, Kyeoung-Hwa; Kim, Eun-Young; Lee, Su-Yeon; Ko, Jung-Jae; Lee, Kyung-Ah

    2016-04-01

    Mouse oocytes begin to mature in vitro once liberated from ovarian follicles. Previously, we showed that oocyte-specific homeobox 4 (Obox4) is critical for maintaining the intact nuclear membrane of the germinal vesicle (GV) in oocytes and for completing meiosis at the metaphase I-II (MI-MII) transition. This study further examines the molecular mechanisms of OBOX4 in regulating GV nuclear membrane breakdown. Maturation-promoting factor (MPF) and MAPK are normally inactive in GV stage oocytes but were activated prematurely in arrested GV stage oocytes by 3-isobutyl-1-metyl-xanthine (IBMX) in vitro after Obox4 RNA interference (RNAi). Furthermore, signal transducer and activator of transcription 3 (STAT3) was significantly activated by Obox4 RNAi. We confirmed that this Obox4 RNAi-induced premature STAT3 and MPF/MAPK activation at the GV stage provoked subsequent GV breakdown (GVBD) despite the opposing force of high cAMP in the IBMX-supplemented medium to maintain intact GV. When cumulus-oocyte complexes were exposed to interferon α (IFNA), a STAT3 activator, oocytes matured and cumulus cells expanded to resume nuclear maturation in IBMX-supplemented medium, suggesting that STAT3 activation is sufficient for stimulating the continuation of meiosis. Using Stattic, a specific STAT3 inhibitor, we confirmed that GVBD involves STAT3 activation in Obox4-silenced oocytes. Based on these findings, we concluded that i) Obox4 is an important upstream regulator of MPF/MAPK and STAT3 signaling, and ii) Obox4 is a key regulator of the GV arrest mechanism in oocytes.

  8. Adenosine triphosphate prevents serum deprivation-induced apoptosis in human mesenchymal stem cells via activation of the MAPK signaling pathways.

    PubMed

    Berlier, Jessica L; Rigutto, Sabrina; Dalla Valle, Antoine; Lechanteur, Jessica; Soyfoo, Muhammad S; Gangji, Valerie; Rasschaert, Joanne

    2015-01-01

    Human mesenchymal stem cells (hMSC) are multipotent cells derived from various sources including adipose and placental tissues as well as bone marrow. Owing to their regenerative and immunomodulatory properties, their use as a potential therapeutic tool is being extensively tested. However, one of the major hurdles in using cell-based therapy is the use of fetal bovine serum that can trigger immune responses, viral and prion diseases. The development of a culture medium devoid of serum while preserving cell viability is therefore a major challenge. In this study, we demonstrated that adenosine triphosphate (ATP) restrained serum deprivation-induced cell death in hMSC by preventing caspases 3/7 activation and modulating ERK1/2 and p38 MAPK signaling pathways. We also showed that serum deprivation conditions triggered dephosphorylation of the proapoptotic protein Bad leading to cell death. Adjunction of ATP restored the phosphorylation state of Bad. Furthermore, ATP significantly modulated the expression of proapoptopic and antiapoptotic genes, in favor of an antiapoptotic profile expression. Finally, we established that hMSC released a high amount of ATP in the extracellular medium when cultured in a serum-free medium. Collectively, our results demonstrate that ATP favors hMSC viability in serum deprivation conditions. Moreover, they shed light on the cardinal role of the MAPK pathways, ERK1/2 and p38 MAPK, in promoting hMSC survival.

  9. 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

  10. 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.

  11. TLR signaling paralyzes monocyte chemotaxis through synergized effects of p38 MAPK and global Rap-1 activation.

    PubMed

    Yi, Ling; Chandrasekaran, Prabha; Venkatesan, Sundararajan

    2012-01-01

    Toll-like receptors (TLRs) that recognize pathogen associated molecular patterns and chemoattractant receptors (CKRs) that orchestrate leukocyte migration to infected tissue are two arms of host innate immunity. Although TLR signaling induces synthesis and secretion of proinflammatory cytokines and chemokines, which recruit leukocytes, many studies have reported the paradoxical observation that TLR stimulation inhibits leukocyte chemotaxis in vitro and impairs their recruitment to tissues during sepsis. There is consensus that physical loss of chemokine receptor (CKR) at the RNA or protein level or receptor usage switching are the mechanisms underlying this effect. We show here that a brief (<15 min) stimulation with LPS (lipopolysaccharide) at ~0.2 ng/ml inhibited chemotactic response from CCR2, CXCR4 and FPR receptors in monocytes without downmodulation of receptors. A 3 min LPS pre-treatment abolished the polarized accumulation of F-actin, integrins and PIP(3) (phosphatidylinositol-3,4,5-trisphosphate) in response to chemokines in monocytes, but not in polymorphonuclear neutrophils (PMNs). If chemoattractants were added before or simultaneously with LPS, chemotactic polarization was preserved. LPS did not alter the initial G-protein signaling, or endocytosis kinetics of agonist-occupied chemoattractant receptors (CKRs). The chemotaxis arrest did not result from downmodulation of receptors or from inordinate increase in adhesion. LPS induced rapid p38 MAPK activation, global redistribution of activated Rap1 (Ras-proximate-1 or Ras-related protein 1) GTPase and Rap1GEF (guanylate exchange factor) Epac1 (exchange proteins activated by cyclic AMP) and disruption of intracellular gradient. Co-inhibition of p38 MAPK and Rap1 GTPase reversed the LPS induced breakdown of chemotaxis suggesting that LPS effect requires the combined function of p38 MAPK and Rap1 GTPase.

  12. CCN1 promotes IL-1β production in keratinocytes by activating p38 MAPK signaling in psoriasis

    PubMed Central

    Sun, Yue; Zhang, Jie; Zhai, Tianhang; Li, Huidan; Li, Haichuan; Huo, Rongfen; Shen, Baihua; Wang, Beiqing; Chen, Xiangdong; Li, Ningli; Teng, Jialin

    2017-01-01

    CCN1, an extracellular protein also known as cysteine-rich protein 61 (Cyr61), is a novel pro-inflammatory factor involved in the pathogenesis of rheumatoid arthritis. As an inflammatory disease, psoriasis is characterized by keratinocyte activation-induced epidermal hyperplasia and cytokine-mediated inflammation. We demonstrated in our previous study that CCN1 promoted keratinocyte activation in psoriasis. However, the role of CCN1 in regulating inflammation in psoriasis is still unknown. Here, we showed that CCN1 increased inflammatory cytokine IL-1β production in keratinocytes. Furthermore, endogenous ATP and caspase-1 were required for mature IL-1β production stimulated by CCN1 in keratinocytes. After binding to the receptor of integrin α6β1, CCN1 activated the downstream p38 MAPK signaling pathway, thus inducing the expression of IL-1β. In addition, we inhibited CCN1 function in mouse models of psoriasis, and decreased IL-1β production was observed in vivo. Overall, we showed that CCN1 increased IL-1β production via p38 MAPK signaling, indicating a role for CCN1 protein in regulating inflammation in psoriasis. PMID:28266627

  13. ROCK activity affects IL-1-induced signaling possibly through MKK4 and p38 MAPK in Caco-2 cells.

    PubMed

    Banerjee, Sayantan; McGee, Dennis W

    2016-09-01

    Elevated levels of interleukin-1 (IL-1) accompany inflammatory bowel disease. IL-1-stimulated intestinal epithelial cells can secrete potent chemokines like CXCL8 to exacerbate inflammation. Previously, we found that inhibiting the Rho-associated kinase (ROCK) could inhibit IL-1- or TNF-α-induced CXCL8 secretion by the Caco-2 colonic epithelial cell line. This ROCK inhibition did not affect IκBα phosphorylation and degradation, but suppressed the phosphorylation of c-Jun N-terminal kinase (JNK). Therefore, ROCK must play an important role in epithelial cell CXCL8 responses through an effect on the JNK signaling pathway. Here, we extend these studies by showing that inhibiting ROCK suppressed the IL-1-induced phosphorylation of MKK4, a known activator of JNK, but not MKK7. Yet, ROCK inhibition had no significant effect on the IL-1-induced phosphorylation of extracellular-signal-regulated kinase (ERK) 1/2. Inhibiting ROCK also suppressed the phosphorylation of p38 MAPK after IL-1 stimulation, but this inhibition had no significant effect on the stability of CXCL8 messenger RNA (mRNA) after IL-1 stimulation. These results suggest that ROCK may be important in IL-1-induced signaling through MKK4 to JNK and the activation of p38 MAPK. Finally, inhibiting ROCK in IL-1 and TNF-α co-stimulated Caco-2 cells also resulted in a significant suppression of CXCL8 secretion and mRNA levels suggesting that inhibiting ROCK may be a mechanism to inhibit the overall response of epithelial cells to both cytokines. These studies indicate a novel signaling event, which could provide a target for suppressing intestinal epithelial cells (IEC) chemokine responses involved in mucosal inflammation.

  14. 7-O-Geranylquercetin induces apoptosis in gastric cancer cells via ROS-MAPK mediated mitochondrial signaling pathway activation.

    PubMed

    Zhu, Yanyan; Jiang, Yameng; Shi, Lei; Du, Linying; Xu, Xiaodong; Wang, Enxia; Sun, Yong; Guo, Xin; Zou, Boyang; Wang, Huaxin; Wang, Changyuan; Sun, Lidan; Zhen, Yuhong

    2017-03-01

    7-O-Geranylquercetin (GQ) is a novel O-alkylated derivate of quercetin. In this study, we evaluated its apoptosis induction effects in human gastric cancer cell lines SGC-7901 and MGC-803 and explored the potential molecular mechanisms. The results demonstrated that GQ lowered viability of SGC-7901 and MGC-803 cells in a dose- and time-dependent manner without apparent cytotoxicity to human gastric epithelial cell line GES-1. GQ could induce apoptosis in SGC-7901 and MGC-803cells, and arrest the gastric cancer cells at G2/M phase. Mechanism study showed that GQ triggered generation of reactive oxygen species (ROS), then activated p38 and JNK signaling pathways, subsequently led to mitochondrial impairment by regulating the expression of Bcl-2, Bcl-xl and Bax, and finally promoted the release of cytochrome c and the activation of caspases to induce apoptosis. In addition, Z-VAD-FMK (caspase inhibitor) could reverse GQ-induced apoptosis. SB203580 (p38 inhibitor) and SP600125 (JNK inhibitor) could rescue GQ-induced cell death and attenuate mitochondrial signal pathway activation. Furthermore, NAC (ROS inhibitor) could rescue GQ-induced cell death, reduce ROS generation, decrease the phosphorylation of p38 and JNK, and then attenuate the activation of mitochondrial signal pathway. Taken together, GQ induces caspase-dependent apoptosis in gastric cancer cells through activating ROS-MAPK mediated mitochondrial signal pathway. This study highlights the potential use of GQ as a gastric cancer therapeutic agent.

  15. Titanium dioxide nanoparticles stimulate sea urchin immune cell phagocytic activity involving TLR/p38 MAPK-mediated signalling pathway

    PubMed Central

    Pinsino, Annalisa; Russo, Roberta; Bonaventura, Rosa; Brunelli, Andrea; Marcomini, Antonio; Matranga, Valeria

    2015-01-01

    Titanium dioxide nanoparticles (TiO2NPs) are one of the most widespread-engineered particles in use for drug delivery, cosmetics, and electronics. However, TiO2NP safety is still an open issue, even for ethical reasons. In this work, we investigated the sea urchin Paracentrotus lividus immune cell model as a proxy to humans, to elucidate a potential pathway that can be involved in the persistent TiO2NP-immune cell interaction in vivo. Morphology, phagocytic ability, changes in activation/inactivation of a few mitogen-activated protein kinases (p38 MAPK, ERK), variations of other key proteins triggering immune response (Toll-like receptor 4-like, Heat shock protein 70, Interleukin-6) and modifications in the expression of related immune response genes were investigated. Our findings indicate that TiO2NPs influence the signal transduction downstream targets of p38 MAPK without eliciting an inflammatory response or other harmful effects on biological functions. We strongly recommend sea urchin immune cells as a new powerful model for nano-safety/nano-toxicity investigations without the ethical normative issue. PMID:26412401

  16. Mobile phone electromagnetic radiation activates MAPK signaling and regulates viability in Drosophila.

    PubMed

    Lee, Kyu-Sun; Choi, Jong-Soon; Hong, Sae-Yong; Son, Tae-Ho; Yu, Kweon

    2008-07-01

    Mobile phones are widely used in the modern world. However, biological effects of electromagnetic radiation produced by mobile phones are largely unknown. In this report, we show biological effects of the mobile phone 835 MHz electromagnetic field (EMF) in the Drosophila model system. When flies were exposed to the specific absorption rate (SAR) 1.6 W/kg, which is the proposed exposure limit by the American National Standards Institute (ANSI), more than 90% of the flies were viable even after the 30 h exposure. However, in the SAR 4.0 W/kg strong EMF exposure, viability dropped from the 12 h exposure. These EMF exposures triggered stress response and increased the production of reactive oxygen species. The EMF exposures also activated extracellular signal regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling, but not p38 kinase signaling. Interestingly, SAR 1.6 W/kg activated mainly ERK signaling and expression of an anti-apoptotic gene, whereas SAR 4.0 W/kg strongly activated JNK signaling and expression of apoptotic genes. In addition, SAR 4.0 W/kg amplified the number of apoptotic cells in the fly brain. These findings demonstrate that the exposure limit on electromagnetic radiation proposed by ANSI triggered ERK-survival signaling but the strong electromagnetic radiation activated JNK-apoptotic signaling in Drosophila.

  17. Phosphoproteomic Analysis of Protein Kinase C Signaling in Saccharomyces cerevisiae Reveals Slt2 Mitogen-activated Protein Kinase (MAPK)-dependent Phosphorylation of Eisosome Core Components*

    PubMed Central

    Mascaraque, Victoria; Hernáez, María Luisa; Jiménez-Sánchez, María; Hansen, Rasmus; Gil, Concha; Martín, Humberto; Cid, Víctor J.; Molina, María

    2013-01-01

    The cell wall integrity (CWI) pathway of the model organism Saccharomyces cerevisiae has been thoroughly studied as a paradigm of the mitogen-activated protein kinase (MAPK) pathway. It consists of a classic MAPK module comprising the Bck1 MAPK kinase kinase, two redundant MAPK kinases (Mkk1 and Mkk2), and the Slt2 MAPK. This module is activated under a variety of stimuli related to cell wall homeostasis by Pkc1, the only member of the protein kinase C family in budding yeast. Quantitative phosphoproteomics based on stable isotope labeling of amino acids in cell culture is a powerful tool for globally studying protein phosphorylation. Here we report an analysis of the yeast phosphoproteome upon overexpression of a PKC1 hyperactive allele that specifically activates CWI MAPK signaling in the absence of external stimuli. We found 82 phosphopeptides originating from 43 proteins that showed enhanced phosphorylation in these conditions. The MAPK S/T-P target motif was significantly overrepresented in these phosphopeptides. Hyperphosphorylated proteins provide putative novel targets of the Pkc1–cell wall integrity pathway involved in diverse functions such as the control of gene expression, protein synthesis, cytoskeleton maintenance, DNA repair, and metabolism. Remarkably, five components of the plasma-membrane-associated protein complex known as eisosomes were found among the up-regulated proteins. We show here that Pkc1-induced phosphorylation of the eisosome core components Pil1 and Lsp1 was not exerted directly by Pkc1, but involved signaling through the Slt2 MAPK module. PMID:23221999

  18. Activation of MAPK overrides the termination of myelin growth and replaces Nrg1/ErbB3 signals during Schwann cell development and myelination

    PubMed Central

    Sheean, Maria E.; McShane, Erik; Cheret, Cyril; Walcher, Jan; Müller, Thomas; Wulf-Goldenberg, Annika; Hoelper, Soraya; Garratt, Alistair N.; Krüger, Markus; Rajewsky, Klaus; Meijer, Dies; Birchmeier, Walter; Lewin, Gary R.; Selbach, Matthias; Birchmeier, Carmen

    2014-01-01

    Myelination depends on the synthesis of large amounts of myelin transcripts and proteins and is controlled by Nrg1/ErbB/Shp2 signaling. We developed a novel pulse labeling strategy based on stable isotope labeling with amino acids in cell culture (SILAC) to measure the dynamics of myelin protein production in mice. We found that protein synthesis is dampened in the maturing postnatal peripheral nervous system, and myelination then slows down. Remarkably, sustained activation of MAPK signaling by expression of the Mek1DD allele in mice overcomes the signals that end myelination, resulting in continuous myelin growth. MAPK activation leads to minor changes in transcript levels but massively up-regulates protein production. Pharmacological interference in vivo demonstrates that the effects of activated MAPK signaling on translation are mediated by mTOR-independent mechanisms but in part also by mTOR-dependent mechanisms. Previous work demonstrated that loss of ErbB3/Shp2 signaling impairs Schwann cell development and disrupts the myelination program. We found that activated MAPK signaling strikingly compensates for the absence of ErbB3 or Shp2 during Schwann cell development and myelination. PMID:24493648

  19. Integration analysis of MKK and MAPK family members highlights potential MAPK signaling modules in cotton

    PubMed Central

    Zhang, Xueying; Xu, Xiaoyang; Yu, Yujia; Chen, Chuan; Wang, Jing; Cai, Caiping; Guo, Wangzhen

    2016-01-01

    Mitogen-activated protein kinase (MAPK) cascades play a crucial role in plant growth and development, as well as their biotic and abiotic stress responses. As a nodal point of the MAPK cascade, the MKK gene family has not been systematically studied in cotton. Here, we identified 11 putative MKK genes in the Gossypium raimondii genome. Phylogenetic analysis showed that the MKKs were supported by architectures of conserved protein motifs. Expression patterns of MKKs under hormone treatments or abiotic stresses revealed their diverse functions in stress responses. Based on a yeast two hybrid, a total of 63 interactive pairs of MKKs and MAPKs were identified in cotton. Among these, 40 interactive pairs were newly identified compared to that reported previously in Arabidopsis. Integration analysis of the interaction network and expression patterns of MKK and MAPK family members revealed 13 potential MAPK signaling modules that are involved in the complicated cross-talk between hormones and abiotic stresses. Taken together, our data enhance the understanding of the evolution and function of MAPK cascades in cotton, and lay the foundation for the improvement of various defense responses that use MAPK signaling modules in the future. PMID:27417377

  20. Glial activation in the periaqueductal gray promotes descending facilitation of neuropathic pain through the p38 MAPK signaling pathway.

    PubMed

    Ni, Hua-Dong; Yao, Ming; Huang, Bing; Xu, Long-Sheng; Zheng, Ying; Chu, Yu-Xia; Wang, Han-Qi; Liu, Ming-Juan; Xu, Shi-Jie; Li, Hong-Bo

    2016-01-01

    The midbrain ventrolateral periaqueductal gray (VL-PAG) is a key component that mediates pain modulation. Although spinal cord glial cells appear to play an important role in chronic pain development, the precise mechanisms involving descending facilitation pathways from the PAG following nerve injury are poorly understood. This study shows that cellular events that occur during glial activation in the VL-PAG may promote descending facilitation from the PAG during neuropathic pain. Chronic constriction nerve injury (CCI) was induced by ligature construction of the sciatic nerve in male Sprague-Dawley rats. Behavioral responses to noxious mechanical (paw withdrawal threshold; PWT) and thermal (paw withdrawal latency; PWL) stimuli were evaluated. After CCI, immunohistochemical and Western blot analysis of microglia and astrocytes in the VL-PAG showed morphological and quantitative changes indicative of activation in microglia and astrocytes. Intra-VL-PAG injection of microglial or astrocytic inhibitors attenuated PWT and PWL at days 7 and 14, respectively, following CCI. We also evaluated the effects of intra-VL-PAG administration of the phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK) inhibitor SB 203580 at day 7 after CCI. This treatment abolished microglial activation and produced a significant time-dependent attenuation of PWT and PWL. Western blot analysis showed localized expression of p-p38 in the VL-PAG after CCI. P-p38 was expressed in labeled microglia of the VL-PAG but was not present in astrocytes and neurons on day 7 after CCI. These results demonstrate that CCI-induced neuropathic pain is associated with glial activation in the VL-PAG, which likely participates in descending pain facilitation through the p38 MAPK signaling pathway.

  1. Polysaccharides from Capsosiphon fulvescens stimulate the growth of IEC-6 Cells by activating the MAPK signaling pathway.

    PubMed

    Go, Hiroe; Hwang, Hye-Jung; Nam, Taek-Jeong

    2011-06-01

    Seaweed extracts show diverse bioactivities, such as antioxidant and antitumor activity. Capsosiphon fulvescens is a green alga that is abundant along the southwest coast of South Korea. Although it is consumed for its purported health-enhancing properties, particularly as a treatment for stomach disorders and hangovers, the health effects of dietary C. fulvescens remain unclear. We extracted polysaccharides from C. fulvescens (Cf-PS), investigated their effects on the proliferation of rat small intestinal epithelial IEC-6 cells, and determined the signaling cascade involved. We cultured IEC-6 cells in the presence of Cf-PS, which stimulated cell proliferation in a dose-dependent manner, and analyzed the Wnt and MAPK signaling pathways, which are related to cell proliferation. Cf-PS treatment induced the translocation of β-catenin, an effector of the Wnt signaling pathway, from the cytosol to the nucleus and increased the expression of cyclinD1 and c-myc. Cf-PS also induced ERK1/2 phosphorylation, which is activated by mitogenic and proliferative stimuli such as growth factors, but the phosphorylation of JNK and p38 was not enhanced. Our results show that Cf-PS regulates proliferation via stimulating the nuclear translocation of β-catenin and ERK1/2 activation in intestinal epithelial cells.

  2. Calycosin Promotes Angiogenesis Involving Estrogen Receptor and Mitogen-Activated Protein Kinase (MAPK) Signaling Pathway in Zebrafish and HUVEC

    PubMed Central

    Li, Zhen Hua; Zhang, Zai Jun; Hu, Guang; Cheang, Lorita Chi Veng; Alex, Deepa; Hoi, Maggie Pui Man; Kwan, Yiu Wa; Chan, Shun Wan; Leung, George Pak Heng; Lee, Simon Ming Yuen

    2010-01-01

    Background Angiogenesis plays an important role in a wide range of physiological processes, and many diseases are associated with the dysregulation of angiogenesis. Radix Astragali is a Chinese medicinal herb commonly used for treating cardiovascular disorders and has been shown to possess angiogenic effect in previous studies but its active constituent and underlying mechanism remain unclear. The present study investigates the angiogenic effects of calycosin, a major isoflavonoid isolated from Radix Astragali, in vitro and in vivo. Methodology Tg(fli1:EGFP) and Tg(fli1:nEGFP) transgenic zebrafish embryos were treated with different concentrations of calycosin (10, 30, 100 µM) from 72 hpf to 96 hpf prior morphological observation and angiogenesis phenotypes assessment. Zebrafish embryos were exposed to calycosin (10, 100 µM) from 72 hpf to 78 hpf before gene-expression analysis. The effects of VEGFR tyrosine kinase inhibitor on calycosin-induced angiogenesis were studied using 72 hpf Tg(fli1:EGFP) and Tg(fli1:nEGFP) zebrafish embryos. The pro-angiogenic effects of calycosin were compared with raloxifene and tamoxifen in 72 hpf Tg(fli1:EGFP) zebrafish embryos. The binding affinities of calycosin to estrogen receptors (ERs) were evaluated by cell-free and cell-based estrogen receptor binding assays. Human umbilical vein endothelial cell cultures (HUVEC) were pretreated with different concentrations of calycosin (3, 10, 30, 100 µM) for 48 h then tested for cell viability and tube formation. The role of MAPK signaling in calycosin-induced angiogenesis was evaluated using western blotting. Conclusion Calycosin was shown to induce angiogenesis in human umbilical vein endothelial cell cultures (HUVEC) in vitro and zebrafish embryos in vivo via the up-regulation of vascular endothelial growth factor (VEGF), VEGFR1 and VEGFR2 mRNA expression. It was demonstrated that calycosin acted similar to other selective estrogen receptor modulators (SERMs), such as raloxifene and

  3. FAM83B-mediated activation of PI3K/AKT and MAPK signaling cooperates to promote epithelial cell transformation and resistance to targeted therapies

    PubMed Central

    Cipriano, Rocky; Miskimen, Kristy L.S.; Bryson, Benjamin L.; Foy, Chase R.; Bartel, Courtney A.; Jackson, Mark W.

    2013-01-01

    Therapies targeting MAPK and AKT/mTOR signaling are currently being evaluated in clinical trials for several tumor types. However, recent studies suggest that these therapies may be limited due to acquired cancer cell resistance and a small therapeutic index between normal and cancer cells. The identification of novel proteins that are involved in MAPK or AKT/mTOR signaling and differentially expressed between normal and cancer cells will provide mechanistically distinct therapeutic targets with the potential to inhibit these key cancer-associated pathways. We recently identified FAM83B as a novel, previously uncharacterized oncogene capable of hyperactivating MAPK and mTOR signaling and driving the tumorigenicity of immortalized human mammary epithelial cells (HMEC). We show here that elevated FAM83B expression also activates the PI3K/AKT signaling pathway and confers a decreased sensitivity to PI3K, AKT, and mTOR inhibitors. FAM83B co-precipitated with the p85α and p110α subunits of PI3K, as well as AKT, and increased p110α and AKT membrane localization, consistent with elevated PI3K/AKT signaling. In tumor-derived cells harboring elevated FAM83B expression, ablation of FAM83B decreased p110α and AKT membrane localization, suppressed AKT phosphorylation, and diminished proliferation, AIG, and tumorigenicity in vivo. We propose that the level of FAM83B expression may be an important factor to consider when combined therapies targeting MAPK and AKT/mTOR signaling are used. Moreover, the identification of FAM83B as a novel oncogene and its integral involvement in activating PI3K/AKT and MAPK provides a foundation for future therapies aimed at targeting FAM83B in order to suppress the growth of PI3K/AKT- and MAPK-driven cancers. PMID:23676467

  4. 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

  5. Timing of mitogen-activated protein kinase (MAPK) activation in the rat pineal gland.

    PubMed

    Ho, A K; Price, D M; Terriff, D; Chik, C L

    2006-06-27

    Activation of members of the mitogen-activated protein kinase (MAPK) family of signaling cascades is a tightly controlled event in rat pinealocytes. Cell culture studies indicate that whereas the NE-->cGMP activation of p42/44MAPK is rapid and transient, the NE-->cAMP activation of p38MAPK is slower and more sustained. The decline in the p42/44MAPK response is in part due to the induction of MAPK phosphatase-1 by NE. In comparison, p38MAPK activation is tightly coupled to the synthesis and degradation of an upstream element in its activation cascade. Whole animal studies confirm activation of p42/44MAPK occurring during the early part of night and precedes p38MAPK activation. Studies with selective MAPK inhibitors reveal a modulating effect of MAPKs on arylalkylamine-N-acetyltransferse (AA-NAT) activity, with involvement of p42/44MAPK in the induction of AA-NAT and p38MAPK participating in the amplitude and duration of the AA-NAT response. These effects of p42/44MAPK and p38MAPK on AA-NAT activity match their timing of activation. Taken together, our studies on the timing of MAPK activation and regulation of AA-NAT by MAPKs add to the importance of MAPKs in regulating the circadian biology of the pineal gland.

  6. Endoplasmic reticulum stress increases brain MAPK signaling, inflammation and renin-angiotensin system activity and sympathetic nerve activity in heart failure.

    PubMed

    Wei, Shun-Guang; Yu, Yang; Weiss, Robert M; Felder, Robert B

    2016-10-01

    We previously reported that endoplasmic reticulum (ER) stress is induced in the subfornical organ (SFO) and the hypothalamic paraventricular nucleus (PVN) of heart failure (HF) rats and is reduced by inhibition of mitogen-activated protein kinase (MAPK) signaling. The present study further examined the relationship between brain MAPK signaling, ER stress, and sympathetic excitation in HF. Sham-operated (Sham) and HF rats received a 4-wk intracerebroventricular (ICV) infusion of vehicle (Veh) or the ER stress inhibitor tauroursodeoxycholic acid (TUDCA, 10 μg/day). Lower mRNA levels of the ER stress biomarkers GRP78, ATF6, ATF4, and XBP-1s in the SFO and PVN of TUDCA-treated HF rats validated the efficacy of the TUDCA dose. The elevated levels of phosphorylated p44/42 and p38 MAPK in SFO and PVN of Veh-treated HF rats, compared with Sham rats, were significantly reduced in TUDCA-treated HF rats as shown by Western blot and immunofluorescent staining. Plasma norepinephrine levels were higher in Veh-treated HF rats, compared with Veh-treated Sham rats, and were significantly lower in the TUDCA-treated HF rats. TUDCA-treated HF rats also had lower mRNA levels for angiotensin converting enzyme, angiotensin II type 1 receptor, tumor necrosis factor-α, interleukin-1β, cyclooxygenase-2, and NF-κB p65, and a higher mRNA level of IκB-α, in the SFO and PVN than Veh-treated HF rats. These data suggest that ER stress contributes to the augmented sympathetic activity in HF by inducing MAPK signaling, thereby promoting inflammation and renin-angiotensin system activity in key cardiovascular regulatory regions of the brain.

  7. Calcium oxalate crystals induces tight junction disruption in distal renal tubular epithelial cells by activating ROS/Akt/p38 MAPK signaling pathway.

    PubMed

    Yu, Lei; Gan, Xiuguo; Liu, Xukun; An, Ruihua

    2017-11-01

    Tight junction plays important roles in regulating paracellular transports and maintaining cell polarity. Calcium oxalate monohydrate (COM) crystals, the major crystalline composition of kidney stones, have been demonstrated to be able to cause tight junction disruption to accelerate renal cell injury. However, the cellular signaling involved in COM crystal-induced tight junction disruption remains largely to be investigated. In the present study, we proved that COM crystals induced tight junction disruption by activating ROS/Akt/p38 MAPK pathway. Treating Madin-Darby canine kidney (MDCK) cells with COM crystals induced a substantial increasing of ROS generation and activation of Akt that triggered subsequential activation of ASK1 and p38 mitogen-activated protein kinase (MAPK). Western blot revealed a significantly decreased expression of ZO-1 and occludin, two important structural proteins of tight junction. Besides, redistribution and dissociation of ZO-1 were observed by COM crystals treatment. Inhibition of ROS by N-acetyl-l-cysteine (NAC) attenuated the activation of Akt, ASK1, p38 MAPK, and down-regulation of ZO-1 and occludin. The redistribution and dissociation of ZO-1 were also alleviated by NAC treatment. These results indicated that ROS were involved in the regulation of tight junction disruption induced by COM crystals. In addition, the down-regulation of ZO-1 and occludin, the phosphorylation of ASK1 and p38 MAPK were also attenuated by MK-2206, an inhibitor of Akt kinase, implying Akt was involved in the disruption of tight junction upstream of p38 MAPK. Thus, these results suggested that ROS-Akt-p38 MAPK signaling pathway was activated in COM crystal-induced disruption of tight junction in MDCK cells.

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

    PubMed Central

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

    2017-01-01

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

  9. Persistent mechanical stretch-induced calcium overload and MAPK signal activation contributed to SCF reduction in colonic smooth muscle in vivo and in vitro.

    PubMed

    Dong, Fang; Yang, Shu; Sun, Haimei; Yan, Jihong; Guo, Xiaoxia; Li, Dandan; Zhou, Deshan

    2017-04-01

    Gastrointestinal (GI) distention is a common pathological characteristic in most GI motility disorders (GMDs), however, their detail mechanism remains unknown. In this study, we focused on Ca(2+) overload of smooth muscle, which is an early intracellular reaction to stretch, and its downstream MAPK signaling and also reduction of SCF in vivo and in vitro. We successfully established colonic dilation mouse model by keeping incomplete colon obstruction for 8 days. The results showed that persistent colonic dilation clearly induced Ca(2+) overload and activated all the three MAPK family members including JNK, ERK and p38 in smooth muscle tissues. Similar results were obtained from dilated colon of patients with Hirschsprung's disease and stretched primary mouse colonic smooth muscle cells (SMCs). Furthermore, we demonstrated that persistent stretch-induced Ca(2+) overload was originated from extracellular Ca(2+) influx and endoplasmic reticulum (ER) Ca(2+) release identified by treating with different Ca(2+) channel blockers, and was responsible for the persistent activation of MAPK signaling and SCF reduction in colonic SMCs. Our results suggested that Ca(2+) overload caused by smooth muscle stretch led to persistent activation of MAPK signaling which might contribute to the decrease of SCF and development of the GMDs.

  10. Long non-coding RNA Malat1 promotes neurite outgrowth through activation of ERK/MAPK signalling pathway in N2a cells.

    PubMed

    Chen, Lei; Feng, Peimin; Zhu, Xi; He, Shixu; Duan, Jialan; Zhou, Dong

    2016-11-01

    Accumulating evidence suggests that long non-coding RNAs (lncRNAs) are playing critical roles in neurogenesis, yet the underlying molecular mechanisms remain largely elusive. Neurite outgrowth is an early step in neuronal differentiation and regeneration. Using in vitro differentiation of neuroblastoma-derived Neuro-2a (N2a) cell as a model, we performed expression profiling to identify lncRNAs putatively relevant for neurite outgrowth. We identified that Metastasis-associated lung adenocarcinoma transcript 1 (Malat1) was one of the most significantly up-regulated lncRNAs during N2a cell differentiation. Malat1 knockdown resulted in defects in neurite outgrowth as well as enhanced cell death. To pinpoint signalling pathways perturbed by Malat1 depletion, we then performed a reporter-based screening to examine the activities of 50 signalling pathways in Malat1 knockdown cells. We found that Malat1 knockdown resulted in conspicuous inhibition of Mitogen-Activated Protein Kinase (MAPK) signaling pathway as well as abnormal activation of Peroxisome proliferator-activated receptor (PPAR) and P53 signalling pathway. Inhibition of ERK/MAPK pathway with PD98059 potently blocked N2a cell neurite outgrowth, whereas phorbol 12-myristate 13-acetate-induced ERK activation rescued defects in neurite outgrowth and cell death induced by Malat1 depletion. Together, our results established a critical role of Malat1 in the early step of neuronal differentiation through activating ERK/MAPK signalling pathway.

  11. Diverse roles for MAPK signaling in circadian clocks.

    PubMed

    Goldsmith, Charles S; Bell-Pedersen, Deborah

    2013-01-01

    The mitogen-activated protein kinase (MAPK) family of genes aids cells in sensing both extracellular and intracellular stimuli, and emerging data indicate that MAPKs have fundamental, yet diverse, roles in the circadian biological clock. In the mammalian suprachiasmatic nucleus (SCN), MAPK pathways can function as inputs allowing the endogenous clock to entrain to 24h environmental cycles. MAPKs can also interact physically and/or genetically with components of the molecular circadian oscillator, implying that MAPKs can affect the cycling of the clock. Finally, circadian rhythms in MAPK pathway activation exist in many different tissue types and in model organisms, providing a mechanism to coordinately control the expression tissue-specific target genes at the proper time of day. As such, it should probably not come as a surprise that MAPK signaling pathways and circadian clocks affect similar biological processes and defects in either pathway lead to many of the same types of human diseases, highlighting the need to better define the mechanisms that link these two fundamental pathways together.

  12. IGFBP3 and MAPK/ERK signaling mediates melatonin-induced antitumor activity in prostate cancer.

    PubMed

    Mayo, Juan C; Hevia, David; Quiros-Gonzalez, Isabel; Rodriguez-Garcia, Aida; Gonzalez-Menendez, Pedro; Cepas, Vanesa; Gonzalez-Pola, Iván; Sainz, Rosa M

    2017-01-01

    Treatment of prostate cancer (PCa), a leading cause of cancer among males, lacks successful strategies especially in advanced, hormone-refractory stages. Some clinical studies have shown an increase in neuroendocrine-like cells parallel to the tumor progression but their exact role is a matter of debate. The prostate is a well-known target for melatonin, which reduces PCa cells proliferation and induces neuroendocrine differentiation. To evaluate the mechanisms underlying the indole effects on neuroendocrine differentiation and its impact on PCa progression, we used a cell culture model (LNCaP) and a murine model (TRAMP). Persistent ERK1/2 activation was found in both, melatonin and androgen-deprived cells. Melatonin blocked nuclear translocation of androgen receptor (AR), thus confirming anti-androgenic actions of the indole. However, using a comparative genome microarray to check the differentially expressed genes in control, melatonin, or androgen-deprived cells, some differences were found, suggesting a more complex role of the indole. By comparing control cells with those treated with melatonin or depleted of androgen, a cluster of 26 differentially expressed genes (±2.5-fold) was found. Kallikreins (KLK)2 and KLK3 (PSA) were dramatically downregulated by both treatments whereas IGFBP3 and IGF1R were up- and downregulated, respectively, in both experimental groups, thus showing a role for IGF in both scenarios. Finally, melatonin prolonged the survival of TRAMP mice by 33% when given at the beginning or at advances stages of the tumor. Serum IGFBP3 was significantly elevated by the indole in early stages of the tumor, confirming in vivo the role of the IGF signaling in the oncostatic action of the indole.

  13. Selenium inhibits Staphylococcus aureus-induced inflammation by suppressing the activation of the NF-κB and MAPK signalling pathways in RAW264.7 macrophages.

    PubMed

    Bi, Chong-Liang; Wang, Heng; Wang, Yin-Jie; Sun, Jun; Dong, Jun-Sheng; Meng, Xia; Li, Jian-Ji

    2016-06-05

    Inflammation is the hallmark of Staphylococcus aureus (S. aureus)-induced mastitis. Given the interesting relationship between selenium levels and inflammation, this study aimed to demonstrate that selenium modulated the inflammation reaction by suppressing the nuclear factor kappa B (NF-κB) and mitogen activated protein kinase (MAPK) signalling pathways. RAW264.7 macrophages were treated with three different concentrations (1μmol/l, 1.5μmol/l, and 2μmol/l) of Na2SeO3 for 12h before infection with S. aureus for 6h, 8h, and 10h. The results showed that selenium significantly reduced the mRNA expression levels of tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). Furthermore, the release of TNF-α, IL-1β, and IL-6 was decreased significantly with selenium supplementation. In addition, selenium influenced the NF-κB signalling pathway by suppressing the activation of NF-κB p65 and degradation of inhibitory kappa-B (IκB). Selenium also suppressed extracellular regulated protein kinase (Erk), c-Jun N-terminal kinase (Jnk), and p38 phosphorylation through the MAPK signalling pathway. In conclusion, selenium played an anti-inflammation role in RAW264.7 macrophages infected with S. aureus by suppressing the activation of the NF-κB and MAPK signalling pathways.

  14. Targeting MAPK Signaling in Age-Related Macular Degeneration

    PubMed Central

    Kyosseva, Svetlana V.

    2016-01-01

    Age-related macular degeneration (AMD) is a major cause of irreversible blindness affecting elderly people in the world. AMD is a complex multifactorial disease associated with demographic, genetics, and environmental risk factors. It is well established that oxidative stress, inflammation, and apoptosis play critical roles in the pathogenesis of AMD. The mitogen-activated protein kinase (MAPK) signaling pathways are activated by diverse extracellular stimuli, including growth factors, mitogens, hormones, cytokines, and different cellular stressors such as oxidative stress. They regulate cell proliferation, differentiation, survival, and apoptosis. This review addresses the novel findings from human and animal studies on the relationship of MAPK signaling with AMD. The use of specific MAPK inhibitors may represent a potential therapeutic target for the treatment of this debilitating eye disease. PMID:27385915

  15. The crystal structure of phosphorylated MAPK13 reveals common structural features and differences in p38 MAPK family activation

    PubMed Central

    Yurtsever, Zeynep; Scheaffer, Suzanne M.; Romero, Arthur G.; Holtzman, Michael J.; Brett, Tom J.

    2015-01-01

    The p38 MAP kinases (p38 MAPKs) represent an important family centrally involved in mediating extracellular signaling. Recent studies indicate that family members such as MAPK13 (p38δ) display a selective cellular and tissue expression and are therefore involved in specific diseases. Detailed structural studies of all p38 MAPK family members are crucial for the design of specific inhibitors. In order to facilitate such ventures, the structure of MAPK13 was determined in both the inactive (unphosphorylated; MAPK13) and active (dual phosphorylated; MAPK13/pTpY) forms. Here, the first preparation, crystallization and structure determination of MAPK13/pTpY are presented and the structure is compared with the previously reported structure of MAPK13 in order to facilitate studies for structure-based drug design. A comprehensive analysis of inactive versus active structures for the p38 MAPK family is also presented. It is found that MAPK13 undergoes a larger interlobe configurational rearrangement upon activation compared with MAPK14. Surprisingly, the analysis of activated p38 MAPK structures (MAP12/pTpY, MAPK13/pTpY and MAPK14/pTpY) reveals that, despite a high degree of sequence similarity, different side chains are used to coordinate the phosphorylated residues. There are also differences in the rearrangement of the hinge region that occur in MAPK14 compared with MAPK13 which would affect inhibitor binding. A thorough examination of all of the active (phosphorylated) and inactive (unphosphorylated) p38 MAPK family member structures was performed to reveal a common structural basis of activation for the p38 MAP kinase family and to identify structural differences that may be exploited for developing family member-specific inhibitors. PMID:25849390

  16. The crystal structure of phosphorylated MAPK13 reveals common structural features and differences in p38 MAPK family activation.

    PubMed

    Yurtsever, Zeynep; Scheaffer, Suzanne M; Romero, Arthur G; Holtzman, Michael J; Brett, Tom J

    2015-04-01

    The p38 MAP kinases (p38 MAPKs) represent an important family centrally involved in mediating extracellular signaling. Recent studies indicate that family members such as MAPK13 (p38δ) display a selective cellular and tissue expression and are therefore involved in specific diseases. Detailed structural studies of all p38 MAPK family members are crucial for the design of specific inhibitors. In order to facilitate such ventures, the structure of MAPK13 was determined in both the inactive (unphosphorylated; MAPK13) and active (dual phosphorylated; MAPK13/pTpY) forms. Here, the first preparation, crystallization and structure determination of MAPK13/pTpY are presented and the structure is compared with the previously reported structure of MAPK13 in order to facilitate studies for structure-based drug design. A comprehensive analysis of inactive versus active structures for the p38 MAPK family is also presented. It is found that MAPK13 undergoes a larger interlobe configurational rearrangement upon activation compared with MAPK14. Surprisingly, the analysis of activated p38 MAPK structures (MAP12/pTpY, MAPK13/pTpY and MAPK14/pTpY) reveals that, despite a high degree of sequence similarity, different side chains are used to coordinate the phosphorylated residues. There are also differences in the rearrangement of the hinge region that occur in MAPK14 compared with MAPK13 which would affect inhibitor binding. A thorough examination of all of the active (phosphorylated) and inactive (unphosphorylated) p38 MAPK family member structures was performed to reveal a common structural basis of activation for the p38 MAP kinase family and to identify structural differences that may be exploited for developing family member-specific inhibitors.

  17. The Histamine H3 Receptor Differentially Modulates Mitogen-activated Protein Kinase (MAPK) and Akt Signaling in Striatonigral and Striatopallidal Neurons.

    PubMed

    Rapanelli, Maximiliano; Frick, Luciana R; Horn, Kyla D; Schwarcz, Rivka C; Pogorelov, Vladimir; Nairn, Angus C; Pittenger, Christopher

    2016-09-30

    The basal ganglia have a central role in motor patterning, habits, motivated behaviors, and cognition as well as in numerous neuropsychiatric disorders. Receptors for histamine, especially the H3 receptor (H3R), are highly expressed in the striatum, the primary input nucleus of the basal ganglia, but their effects on this circuitry have been little explored. H3R interacts with dopamine (DA) receptors ex vivo; the nature and functional importance of these interactions in vivo remain obscure. We found H3R activation with the agonist R-(-)-α-methylhistamine to produce a unique time- and cell type-dependent profile of molecular signaling events in the striatum. H3 agonist treatment did not detectably alter extracellular DA levels or signaling through the cAMP/DARPP-32 signaling pathway in either D1- or D2-expressing striatal medium spiny neurons (MSNs). In D1-MSNs, H3 agonist treatment transiently activated MAPK signaling and phosphorylation of rpS6 and led to phosphorylation of GSK3β-Ser(9), a novel effect. Consequences of H3 activation in D2-MSNs were completely different. MAPK signaling was unchanged, and GSK3β-Ser(9) phosphorylation was reduced. At the behavioral level, two H3 agonists had no significant effect on locomotion or stereotypy, but they dramatically attenuated the locomotor activation produced by the D1 agonist SKF82958. H3 agonist co-administration blocked the activation of MAPK signaling and the phosphorylation of rpS6 produced by D1 activation in D1-MSNs, paralleling behavioral effects. In contrast, GSK3β-Ser(9) phosphorylation was seen only after H3 agonist treatment, with no interactive effects. H3R signaling has been neglected in models of basal ganglia function and has implications for a range of pathophysiologies.

  18. Subanesthetic Isoflurane Reduces Zymosan-Induced Inflammation in Murine Kupffer Cells by Inhibiting ROS-Activated p38 MAPK/NF-κB Signaling

    PubMed Central

    Wang, Hui; Wang, Lei; Li, Nan-lin; Li, Jun-tang; Yu, Feng; Zhao, Ya-li; Wang, Ling; Yi, Jun; Wang, Ling; Bian, Jie-fang; Chen, Jiang-hao; Yuan, Shi-fang; Wang, Ting; Lv, Yong-gang; Liu, Ning-ning; Zhu, Xiao-shan; Ling, Rui; Yun, Jun

    2014-01-01

    Volatile anesthetic isoflurane (ISO) has immunomodulatory effects. The fungal component zymosan (ZY) induces inflammation through toll-like receptor 2 or dectin-1 signaling. We investigated the molecular actions of subanesthetic (0.7%) ISO against ZY-induced inflammatory activation in murine Kupffer cells (KCs), which are known as the resident macrophages within the liver. We observed that ISO reduced ZY-induced cyclooxygenase 2 upregulation and prostaglandin E2 release, as determined by western blot and radioimmunoassay, respectively. ISO also reduced the production of tumor necrosis factor-α, interleukin-1β, IL-6, high-mobility group box-1, macrophage inflammatory protein-1α, macrophage inflammatory protein-2, and monocyte chemoattractant protein-1 as assessed by enzyme-linked immunosorbent assays. ISO blocked the ZY-induced nuclear translocation and DNA-binding activity of nuclear factor- (NF)-κB p65. Moreover, ISO attenuated ZY-induced p38 mitogen-activated protein kinase (MAPK) activation partly by scavenging reactive oxygen species (ROS); the interregulation that ROS activated p38 MAPK followed by NF-κB activation was crucial for the ZY-induced inflammatory responses in KCs. An in vivo study by peritoneal injection of ZY into BALB/C mice confirmed the anti-inflammatory properties of 0.7% ISO against ZY in KCs. These results suggest that ISO ameliorates ZY-induced inflammatory responses in murine KCs by inhibiting the interconnected ROS/p38 MAPK/NF-κB signaling pathways. PMID:25147596

  19. Protein O-fucosyltransferase 1 promotes trophoblast cell proliferation through activation of MAPK and PI3K/Akt signaling pathways.

    PubMed

    Liu, Chang; Liang, Xiaohua; Wang, Jiao; Zheng, Qin; Zhao, Yue; Khan, Muhammad Noman; Liu, Shuai; Yan, Qiu

    2017-04-01

    Protein O-fucosylation is an important glycosylation modification and plays an important role in embryonic development. Protein O-fucosyltransferase 1 (poFUT1) is an essential enzyme that catalyzes the synthesis of protein O-fucosylation. Our previous studies showed that poFUT1 promoted trophoblast cell migration and invasion at the fetal-maternal interface, but the role of poFUT1 in trophoblast cells proliferation remains unclear. Here, immunohistochemistry data showed that poFUT1 and PCNA levels were decreased in abortion patient's trophoblasts compared with women with normal pregnancies. Our results also showed that poFUT1 promoted trophoblast cell proliferation by CCK-8 assay and cell cycle analysis. PoFUT1 increased the phosphorylation of ERK1/2, p38 MAPK, and PI3K/Akt, while inhibitors of ERK1/2(PD98059), p38 MAPK(SB203580), and PI3K (LY294002) prevented ERK1/2, p38 MAPK, and Akt phosphorylation. Moreover, poFUT1 stimulation of trophoblast cells proliferation correlated with increased cell cycle progression by promoting cells into S-phase. The underlying mechanism involved increased cyclin D1, cyclin E, CDK 2, CDK 4, and pRb expression and decreased levels of the cyclin-dependent kinase inhibitors p21 and p27, which were blocked by inhibitors of the upstream signaling molecules MAPK and PI3K/Akt. In conclusion, poFUT1 promotes trophoblast cell proliferation by activating MAPK and PI3K/Akt signaling pathways.

  20. Cardiotonic pill attenuates white matter and hippocampal damage via inhibiting microglial activation and downregulating ERK and p38 MAPK signaling in chronic cerebral hypoperfused rat

    PubMed Central

    2013-01-01

    Background The cardiotonic pill (CP) is a herbal medicine composed of Salvia miltiorrhiza (SM), Panax notoginseng (PN), and Dryobalanops aromatica Gaertner (DAG) that is widely used to treat cardiovascular diseases. The present experiment was conducted to examine the effects of CP on white matter and hippocampal damage induced by chronic cerebral hypoperfusion. Methods Chronic cerebral hypoperfusion was induced in male Wistar rats by permanent bilateral common carotid artery occlusion (BCCAo). Daily oral administration of CP (200 mg/kg) began 21 days after BCCAo and continued for 42 days. The levels of microglial activation and myelin basic protein (MBP) were measured in the white matter and hippocampus of rats with chronic BCCAo, and the expression levels of mitogen-activated protein kinases (MAPKs) and inflammatory markers such as cyclooxygenase-2, interleukin-1β, and interleukin-6 were examined. Results MBP expression was reduced in the white matter and hippocampal regions of rats that received BCCAo. In contrast, reduced levels of MBP were not observed in BCCAo rats given CP treatments. The administration of CP alleviated microglial activation, the alteration of ERK and p38 MAPK signaling, and inflammatory mediator expression in rats with chronic BCCAo. Conclusion These results suggest that CP may have protective effects against chronic BCCAo-induced white matter and hippocampal damage by inhibiting inflammatory processes including microglial activation and proinflammatory mediator expression, and downreguating the hyperphosphorylation of ERK and p38 MAPK signaling. PMID:24274593

  1. MAPK signaling pathways and HDAC3 activity are disrupted during differentiation of emerin-null myogenic progenitor cells.

    PubMed

    Collins, Carol M; Ellis, Joseph A; Holaska, James M

    2017-04-01

    Mutations in the gene encoding emerin cause Emery-Dreifuss muscular dystrophy (EDMD). Emerin is an integral inner nuclear membrane protein and a component of the nuclear lamina. EDMD is characterized by skeletal muscle wasting, cardiac conduction defects and tendon contractures. The failure to regenerate skeletal muscle is predicted to contribute to the skeletal muscle pathology of EDMD. We hypothesize that muscle regeneration defects are caused by impaired muscle stem cell differentiation. Myogenic progenitors derived from emerin-null mice were used to confirm their impaired differentiation and analyze selected myogenic molecular pathways. Emerin-null progenitors were delayed in their cell cycle exit, had decreased myosin heavy chain (MyHC) expression and formed fewer myotubes. Emerin binds to and activates histone deacetylase 3 (HDAC3). Here, we show that theophylline, an HDAC3-specific activator, improved myotube formation in emerin-null cells. Addition of the HDAC3-specific inhibitor RGFP966 blocked myotube formation and MyHC expression in wild-type and emerin-null myogenic progenitors, but did not affect cell cycle exit. Downregulation of emerin was previously shown to affect the p38 MAPK and ERK/MAPK pathways in C2C12 myoblast differentiation. Using a pure population of myogenic progenitors completely lacking emerin expression, we show that these pathways are also disrupted. ERK inhibition improved MyHC expression in emerin-null cells, but failed to rescue myotube formation or cell cycle exit. Inhibition of p38 MAPK prevented differentiation in both wild-type and emerin-null progenitors. These results show that each of these molecular pathways specifically regulates a particular stage of myogenic differentiation in an emerin-dependent manner. Thus, pharmacological targeting of multiple pathways acting at specific differentiation stages may be a better therapeutic approach in the future to rescue muscle regeneration in vivo.

  2. Effect of hyperprolactinemia on PRL-receptor expression and activation of Stat and Mapk cell signaling in the prostate of long-term sexually-active rats.

    PubMed

    Pascual-Mathey, Luz I; Rojas-Duran, Fausto; Aranda-Abreu, Gonzalo E; Manzo, Jorge; Herrera-Covarrubias, Deissy; Muñoz-Zavaleta, David A; Garcia, Luis I; Hernandez, Ma Elena

    2016-04-01

    The abnormal elevation of serum PRL, referred to as hyperprolactinemia (HyperPRL), produces alterations in several reproductive parameters of male rats such as penile erection or decreased tendency to reach ejaculation. Additionally, this situation produces a significant modification of prostate histology, as observed in the epithelial structure and alveolar area, which could reach a level of hyperplasia in the long-term. In this tissue, HyperPRL produces an increase in expression of PRL receptors and activation of the Stat3 signaling pathway that is correlated with the evolution of prostate pathologies. However, the impact of HyperPRL in long-term sexually active male rats is unknown. In this work, using constantly copulating Wistar male rats with induced HyperPRL, we analyzed the level of serum PRL, the effect on prostate PRL receptors, and activation of pStat3, pStat5 and Mapk signaling pathways. Two procedures to induce HyperPRL were employed, comprising daily IP administration or adenohypophysis transplant, and although neither affected the execution of sexual behavior, the serum PRL profile following successive ejaculations was affected. Messenger RNA expression of the short and long isoforms of the PRL receptor at the ventral prostate was affected in different ways depending on the procedure to induce HyperPRL. The ventral prostate did not show any modification in terms of activation of the pStat5 signaling pathway in subjects with daily administration of PRL, although this was significantly increased in ADH transplanted subjects in the second and fourth consecutive ejaculation. A similar profile was found for the pStat3 pathway which additionally showed a significant increase in the third and fourth ejaculation of daily-injected subjects. The Mapk signaling pathway did not show any modifications in subjects with daily administration of PRL, but showed a significant increase in the second and third ejaculations of subjects with ADH transplants. Thus

  3. Microcystin-LR exhibits immunomodulatory role in mouse primary hepatocytes through activation of the NF-κB and MAPK signaling pathways.

    PubMed

    Zhang, Jianying; Chen, Jin; Xia, Zongping

    2013-11-01

    Microcystin-leucine-arginine (MCLR) is an environmental toxin from harmful algae, which has been linked to hepatotoxicity with high risks associated with liver disease. In this study, we explored the role of MCLR in NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways, which are important in regulating inflammatory and immune responses, in human hepatoma cell line HepG2 and primary mouse hepatocytes (PMHs). By in vitro cell-free and luciferase reporter systems, Western blotting with antiphospho-inhibitory protein of NF-κB (IκBα)/c-Jun N-terminal kinase (JNK)/extracellular signal-regulated kinase 1/2 (ERK1/2) antibody, it was found that at noncytotoxic concentrations (≤ 20 nM MCLR in PMHs, 1-1000 nM in HepG2), MCLR treatment alone promoted activation of NF-κB and MAPK pathways and modulated TNF-α-induced activation of the 2 pathways in both cell models. By ELISA assay, MCLR was found to induce production of proinflammatory cytokine IL-6 in PMHs. At cytotoxic concentrations (≥ 50 nM MCLR in PMHs), MCLR dramatically reduced cell viability and damaged cell morphology in PMHs, as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and transmission electron microscopy analysis. These results suggest that MCLR below 20 nM has significant immunomodulatory activities through activation of NF-κB and MAPK signaling pathways, and PMHs are more sensitive to MCLR-induced cytotoxicity than HepG2. To our knowledge, this is the first report showing the immunomodulatory role of MCLR in hepatocytes. Our results provide a better understanding of the molecular mechanisms underlying MCLR-induced hepatotoxicity.

  4. p38 MAPK Signaling in Osteoblast Differentiation

    PubMed Central

    Rodríguez-Carballo, Eddie; Gámez, Beatriz; Ventura, Francesc

    2016-01-01

    The skeleton is a highly dynamic tissue whose structure relies on the balance between bone deposition and resorption. This equilibrium, which depends on osteoblast and osteoclast functions, is controlled by multiple factors that can be modulated post-translationally. Some of the modulators are Mitogen-activated kinases (MAPKs), whose role has been studied in vivo and in vitro. p38-MAPK modifies the transactivation ability of some key transcription factors in chondrocytes, osteoblasts and osteoclasts, which affects their differentiation and function. Several commercially available inhibitors have helped to determine p38 action on these processes. Although it is frequently mentioned in the literature, this chemical approach is not always as accurate as it should be. Conditional knockouts are a useful genetic tool that could unravel the role of p38 in shaping the skeleton. In this review, we will summarize the state of the art on p38 activity during osteoblast differentiation and function, and emphasize the triggers of this MAPK. PMID:27200351

  5. 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

  6. The immunostimulating activity of quercetin 3-O-xyloside in murine macrophages via activation of the ASK1/MAPK/NF-κB signaling pathway.

    PubMed

    Lee, Jisun; Choi, Ji Won; Sohng, Jae Kyung; Pandey, Ramesh Prasad; Park, Yong Il

    2016-02-01

    Quercetin is a natural plant flavonoid that has been reported to possess a wide range of beneficial health effects, including anti-cancer and anti-inflammatory activities. Glycosylation of natural flavonoids with various sugar moieties can affect their physical, chemical, and biological properties. In this study, quercetin 3-O-xyloside (Quer-xyl) was enzymatically synthesized, and the immunomodulatory activities of quercetin and Quer-xyl were evaluated and compared. The results showed that Quer-xyl more effectively induced the secretion of TNF-α and IL-6 than quercetin by 2.5 and 1.5-fold, respectively. Quer-xyl dose-dependently induced the inducible nitric oxide synthase (iNOS) expression and increased the production of nitric oxide (NO) 1.3-fold more than quercetin. Quer-xyl also increased the phosphorylation of ASK1 and MAPKs (JNK and p38). Treatment with NQDI-1 (an inhibitor of ASK1) significantly attenuated the Quer-xyl-induced up-regulation of TNF-α secretion. The activation and subsequent nuclear translocation of NF-κB were substantially enhanced upon treatment with Quer-xyl (2.5-20 μM), while NQDI-1 treatment blocked the nuclear translocation of NF-κB. These results demonstrated that Quer-xyl can enhance the early innate immunity more effectively than quercetin by activating macrophages to secrete TNF-α and IL-6 through up-regulation of the redox-dependent ASK1/MAPK/NF-κB signaling pathway, suggesting for the first time that Quer-xyl may represent a new immunostimulator.

  7. RNase activity of sialic acid-binding lectin from bullfrog eggs drives antitumor effect via the activation of p38 MAPK to caspase-3/7 signaling pathway in human breast cancer cells

    PubMed Central

    Kariya, Yukiko; Tatsuta, Takeo; Sugawara, Shigeki; Kariya, Yoshinobu; Nitta, Kazuo; Hosono, Masahiro

    2016-01-01

    Sialic acid-binding lectin obtained from bullfrog eggs (SBL) induces cell death in cancer cells but not in normal cells. This antitumor effect is mediated through its ribo-nuclease (RNase) activity. However, the underlying molecular mechanisms remain unclear. We found that the p38 mitogen-activated protein kinase (MAPK) signaling pathway was activated when SBL induced cell death in three human breast cancer cell lines: SK-BR-3, MCF-7, and MDA-MB231. The suppression of p38 MAPK phosphorylation by a p38 MAPK inhibitor as well as short interference RNA knockdown of p38 MAPK expression significantly decreased cell death and increased the cell viability of SBL-treated MDA-MB231 cells. H103A, an SBL mutant lacking in RNase activity, showed decreased SBL-induced cell death compared with native SBL. However, the loss of RNase activity of SBL had no effect on its internalization into cells. The H103A mutant also displayed decreased phosphorylation of p38 MAPK. Moreover, SBL promoted caspase-3/7 activation followed by a cleavage of poly (ADP-ribose)-polymerase, whereas the SBL mutant, H103A, lost this ability. The SBL-induced caspase-3/7 activation was suppressed by the p38 MAPK inhibitor, SB203580, as well as pan-caspase inhibitor, zVAD-fmk. In the presence of zVAD-fmk, the SBL-induced cell death was decreased. In addition, the cell viability of SBL-treated MDA-MB231 cells recovered by zVAD-fmk treatment. Taken together, our results suggest that the RNase activity of SBL leads to breast cancer cell death through the activation of p38 MAPK followed by the activation of caspase-3/7. PMID:27513956

  8. RNase activity of sialic acid-binding lectin from bullfrog eggs drives antitumor effect via the activation of p38 MAPK to caspase-3/7 signaling pathway in human breast cancer cells.

    PubMed

    Kariya, Yukiko; Tatsuta, Takeo; Sugawara, Shigeki; Kariya, Yoshinobu; Nitta, Kazuo; Hosono, Masahiro

    2016-10-01

    Sialic acid-binding lectin obtained from bullfrog eggs (SBL) induces cell death in cancer cells but not in normal cells. This antitumor effect is mediated through its ribonuclease (RNase) activity. However, the underlying molecular mechanisms remain unclear. We found that the p38 mitogen-activated protein kinase (MAPK) signaling pathway was activated when SBL induced cell death in three human breast cancer cell lines: SK-BR-3, MCF-7, and MDA‑MB231. The suppression of p38 MAPK phosphorylation by a p38 MAPK inhibitor as well as short interference RNA knockdown of p38 MAPK expression significantly decreased cell death and increased the cell viability of SBL-treated MDA‑MB231 cells. H103A, an SBL mutant lacking in RNase activity, showed decreased SBL-induced cell death compared with native SBL. However, the loss of RNase activity of SBL had no effect on its internalization into cells. The H103A mutant also displayed decreased phosphorylation of p38 MAPK. Moreover, SBL promoted caspase‑3/7 activation followed by a cleavage of poly (ADP-ribose)-polymerase, whereas the SBL mutant, H103A, lost this ability. The SBL-induced caspase‑3/7 activation was suppressed by the p38 MAPK inhibitor, SB203580, as well as pan-caspase inhibitor, zVAD-fmk. In the presence of zVAD-fmk, the SBL-induced cell death was decreased. In addition, the cell viability of SBL-treated MDA‑MB231 cells recovered by zVAD-fmk treatment. Taken together, our results suggest that the RNase activity of SBL leads to breast cancer cell death through the activation of p38 MAPK followed by the activation of caspase‑3/7.

  9. EGF receptor-dependent mechanism may be involved in the Tamm-Horsfall glycoprotein-enhanced PMN phagocytosis via activating Rho family and MAPK signaling pathway.

    PubMed

    Li, Ko-Jen; Siao, Sue-Cien; Wu, Cheng-Han; Shen, Chieh-Yu; Wu, Tsai-Hung; Tsai, Chang-Youh; Hsieh, Song-Chou; Yu, Chia-Li

    2014-01-21

    Our previous studies showed that urinary Tamm-Horsfall glycoprotein (THP) potently enhanced polymorphonuclear neutrophil (PMN) phagocytosis. However, the domain structure(s), signaling pathway and the intracellular events responsible for THP-enhanced PMN phagocytosis remain to be elucidated. THP was purified from normal human urine. The human promyelocytic leukemia cell line HL-60 was induced to differentiate into PMNs by all-trans retinoid acid. Pretreatment with different MAPK and PI3K inhibitors was used to delineate signaling pathways in THP-enhanced PMN phagocytosis. Phosphorylation of molecules responsible for PMN phagocytosis induced by bacterial lipopolysaccharide (LPS), THP, or human recombinant epidermal growth factor (EGF) was evaluated by western blot. A p38 MAPK inhibitor, SB203580, effectively inhibited both spontaneous and LPS- and THP-induced PMN phagocytosis. Both THP and LPS enhanced the expression of the Rho family proteins Cdc42 and Rac that may lead to F-actin re-arrangement. Further studies suggested that THP and EGF enhance PMN and differentiated HL-60 cell phagocytosis in a similar pattern. Furthermore, the EGF receptor inhibitor GW2974 significantly suppressed THP- and EGF-enhanced PMN phagocytosis and p38 and ERK1/2 phosphorylation in differentiated HL-60 cells. We conclude that EGF receptor-dependent signaling may be involved in THP-enhanced PMN phagocytosis by activating Rho family and MAP kinase.

  10. Plastid-nucleus communication involves calcium-modulated MAPK signalling

    PubMed Central

    Guo, Hailong; Feng, Peiqiang; Chi, Wei; Sun, Xuwu; Xu, Xiumei; Li, Yuan; Ren, Dongtao; Lu, Congming; David Rochaix, Jean; Leister, Dario; Zhang, Lixin

    2016-01-01

    Chloroplast retrograde signals play important roles in coordinating the plastid and nuclear gene expression and are critical for proper chloroplast biogenesis and for maintaining optimal chloroplast functions in response to environmental changes in plants. Until now, the signals and the mechanisms for retrograde signalling remain poorly understood. Here we identify factors that allow the nucleus to perceive stress conditions in the chloroplast and to respond accordingly by inducing or repressing specific nuclear genes encoding plastid proteins. We show that ABI4, which is known to repress the LHCB genes during retrograde signalling, is activated through phosphorylation by the MAP kinases MPK3/MPK6 and the activity of these kinases is regulated through 14-3-3ω-mediated Ca2+-dependent scaffolding depending on the chloroplast calcium sensor protein CAS. These findings uncover an additional mechanism in which chloroplast-modulated Ca2+ signalling controls the MAPK pathway for the activation of critical components of the retrograde signalling chain. PMID:27399341

  11. (+)-Catechin Attenuates NF-κB Activation Through Regulation of Akt, MAPK, and AMPK Signaling Pathways in LPS-Induced BV-2 Microglial Cells.

    PubMed

    Syed Hussein, Sharifah Salwa; Kamarudin, Muhamad Noor Alfarizal; Kadir, Habsah Abdul

    2015-01-01

    (+)-Catechin is a flavanol that possesses various health and medicinal values, which include neuroprotection, anti-oxidation, antitumor and antihepatitis activities. This study investigated the modulatory effects of (+)-catechin on the lipopolysaccharides (LPS)-stimulated BV-2 cells. (+)-catechin attenuated LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and inhibited microglial NO and ROS production. Additionally, (+)-catechin suppressed the production of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6, while augmenting IL-4. (+)-catechin attenuated LPS-induced nuclear factor-κB (NF-κB) p65 nuclear translocation via the inhibition of IκB-α phosphorylation. Moreover, (+)-catechin blocked the activation of Akt and its inhibition was shown to play a crucial role in LPS-induced inflammation in BV-2 microglial cells. (+)-catechin also attenuated the LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK1/2), and p-38 mitogen activated protein kinases (p38 MAPK) and specific inhibitors of ERK1/2 (UO126) and p38 MAPK (SB202190) subsequently down-regulated the expression of the proinflammatory mediators iNOS and COX-2. Further mechanistic study revealed that (+)-catechin acted through the amelioration of the LPS-induced suppression of adenosine monophosphate-activated protein kinase (AMPK) activity. Taken together, our data indicate that (+)-catechin exhibits anti-inflammatory effects in BV-2 cells by suppressing the production of proinflammatory mediators and mitigation of NF-κB through Akt, ERK, p38 MAPK, and AMPK pathways.

  12. The CORM ALF-186 Mediates Anti-Apoptotic Signaling via an Activation of the p38 MAPK after Ischemia and Reperfusion Injury in Retinal Ganglion Cells

    PubMed Central

    Ulbrich, Felix; Kaufmann, Kai B.; Meske, Alexander; Lagrèze, Wolf A.; Augustynik, Michael; Buerkle, Hartmut; Ramao, Carlos C.; Biermann, Julia

    2016-01-01

    Purpose Ischemia and reperfusion injury may induce apoptosis and lead to sustained tissue damage and loss of function, especially in neuronal organs. While carbon monoxide is known to exert protective effects after various harmful events, the mechanism of carbon monoxide releasing molecules in neuronal tissue has not been investigated yet. We hypothesize that the carbon monoxide releasing molecule (CORM) ALF-186, administered after neuronal ischemia-reperfusion injury (IRI), counteracts retinal apoptosis and its involved signaling pathways and consecutively reduces neuronal tissue damage. Methods IRI was performed in rat´s retinae for 1 hour. The water-soluble CORM ALF-186 (10 mg/kg) was administered intravenously via a tail vein after reperfusion. After 24 and 48 hours, retinal tissue was harvested to analyze mRNA and protein expression of Bcl-2, Bax, Caspase-3, ERK1/2, p38 and JNK. Densities of fluorogold pre-labeled retinal ganglion cells (RGC) were analyzed 7 days after IRI. Immunohistochemistry was performed on retinal cross sections. Results ALF-186 significantly reduced IRI mediated loss of RGC. ALF-186 treatment differentially affected mitogen-activated protein kinases (MAPK) phosphorylation: ALF-186 activated p38 and suppressed ERK1/2 phosphorylation, while JNK remained unchanged. Furthermore, ALF-186 treatment affected mitochondrial apoptosis, decreasing pro-apoptotic Bax and Caspase-3-cleavage, but increasing anti-apoptotic Bcl-2. Inhibition of p38-MAPK using SB203580 reduced ALF-186 mediated anti-apoptotic effects. Conclusion In this study, ALF-186 mediated substantial neuroprotection, affecting intracellular apoptotic signaling, mainly via MAPK p38. CORMs may thus represent a promising therapeutic alternative treating neuronal IRI. PMID:27764224

  13. Lycium barbarum polysaccharide LBPF4-OL may be a new Toll-like receptor 4/MD2-MAPK signaling pathway activator and inducer.

    PubMed

    Zhang, Xiao-rui; Qi, Chun-hui; Cheng, Jun-ping; Liu, Gang; Huang, Lin-juan; Wang, Zhong-fu; Zhou, Wen-xia; Zhang, Yong-xiang

    2014-03-01

    Recognition of the utility of the traditional Chinese medicine Lycium barbarum L. has been gradually increasing in Europe and the Americas. Many immunoregulation and antitumor effects of L. barbarum polysaccharides (LBP) have been reported, but its molecular mechanism is not yet clear. In this study, we reported that the activity of the polysaccharide LBPF4-OL, which was purified from LBP, is closely associated with the TLR4-MAPK signaling pathway. We found that LBPF4-OL can significantly induce TNF-α and IL-1β production in peritoneal macrophages isolated from wild-type (C3H/HeN) but not TLR4-deficient mice (C3H/HeJ). We also determined that the proliferation of LBPF4-OL-stimulated lymphocytes from C3H/HeJ mice is significantly weaker than that of lymphocytes from C3H/HeN mice. Furthermore, through a bio-layer interferometry assay, we found that LPS but not LBPF4-OL can directly associate with the TLR4/MD2 molecular complex. Flow cytometry analysis indicated that LBPF4-OL markedly upregulates TLR4/MD2 expression in both peritoneal macrophages and Raw264.7 cells. As its mechanism of action, LBPF4-OL increases the phosphorylation of p38-MAPK and inhibits the phosphorylation of JNK and ERK1/2, as was observed through Western blot analysis. These data suggest that the L. barbarum polysaccharide LBPF4-OL is a new Toll-like receptor 4/MD2-MAPK signaling pathway activator and inducer.

  14. Chloroacetic acid induced neuronal cells death through oxidative stress-mediated p38-MAPK activation pathway regulated mitochondria-dependent apoptotic signals.

    PubMed

    Chen, Chun-Hung; Chen, Sz-Jie; Su, Chin-Chuan; Yen, Cheng-Chieh; Tseng, To-Jung; Jinn, Tzyy-Rong; Tang, Feng-Cheng; Chen, Kuo-Liang; Su, Yi-Chang; Lee, kuan-I; Hung, Dong-Zong; Huang, Chun-Fa

    2013-01-07

    Chloroacetic acid (CA), a toxic chlorinated analog of acetic acid, is widely used in chemical industries as an herbicide, detergent, and disinfectant, and chemical intermediates that are formed during the synthesis of various products. In addition, CA has been found as a by-product of chlorination disinfection of drinking water. However, there is little known about neurotoxic injuries of CA on the mammalian, the toxic effects and molecular mechanisms of CA-induced neuronal cell injury are mostly unknown. In this study, we examined the cytotoxicity of CA on cultured Neuro-2a cells and investigated the possible mechanisms of CA-induced neurotoxicity. Treatment of Neuro-2a cells with CA significantly reduced the number of viable cells (in a dose-dependent manner with a range from 0.1 to 3mM), increased the generation of ROS, and reduced the intracellular levels of glutathione depletion. CA also increased the number of sub-G1 hypodiploid cells; increased mitochondrial dysfunction (loss of MMP, cytochrome c release, and accompanied by Bcl-2 and Mcl-1 down-regulation and Bax up-regulation), and activated the caspase cascades activations, which displayed features of mitochondria-dependent apoptosis pathway. These CA-induced apoptosis-related signals were markedly prevented by the antioxidant N-acetylcysteine (NAC). Moreover, CA activated the JNK and p38-MAPK pathways, but did not that ERK1/2 pathway, in treated Neuro-2a cells. Pretreatment with NAC and specific p38-MAPK inhibitor (SB203580), but not JNK inhibitor (SP600125) effectively abrogated the phosphorylation of p38-MAPK and attenuated the apoptotic signals (including: decrease in cytotoxicity, caspase-3/-7 activation, the cytosolic cytochrome c release, and the reversed alteration of Bcl-2 and Bax mRNA) in CA-treated Neuro-2a cells. Taken together, these data suggest that oxidative stress-induced p38-MAPK activated pathway-regulated mitochondria-dependent apoptosis plays an important role in CA-caused neuronal cell

  15. Caenorhabditis elegans mom-4 is required for the activation of the p38 MAPK signaling pathway in the response to Pseudomonas aeruginosa infection.

    PubMed

    Xu, Ajing; Shi, Guojun; Liu, Feng; Ge, Baoxue

    2013-01-01

    The p38 mitogen-activated protein kinase (MAPK) plays an evolutionarily conserved role in the cellular response to microbial infection and environmental stress. Activation of p38 is mediated through phosphorylation by upstream MAPKK, which in turn is activated by MAPKKK. In the Caenorhabditis elegans, the p38 MAPK (also called PMK-1) signaling pathway has been shown to be required in its resistance to bacterial infection. However, how different upstream MAP2Ks and MAP3Ks specifically contribute to the activation of PMK-1 in response to bacterial infection still is not clearly understood. By using double-stranded RNA-mediated interference (RNAi) and genetic mutants of C. elegans, we demonstrate that C. elegans MOM-4, a mammalian TAK1 homolog, is required for the resistance of C. elegans to a P. aeruginosa infection. We have also found that the MKK-4 of C. elegans is required for P. aeruginosa resistance, but not through the regulation of DLK-1. In summary, our results indicate that different upstream MAPKKKs or MAPKKs regulate the activation of PMK-1 in response to P. Aeruginosa.

  16. p38 MAPK Signaling in Postnatal Tendon Growth and Remodeling

    PubMed Central

    Schwartz, Andrew J.; Sarver, Dylan C.; Sugg, Kristoffer B.; Dzierzawski, Justin T.; Gumucio, Jonathan P.; Mendias, Christopher L.

    2015-01-01

    Tendon is a dynamic tissue whose structure and function is influenced by mechanical loading, but little is known about the fundamental mechanisms that regulate tendon growth and remodeling in vivo. Data from cultured tendon fibroblasts indicated that the p38 MAPK pathway plays an important role in tendon fibroblast proliferation and collagen synthesis in vitro. To gain greater insight into the mechanisms of tendon growth, and explore the role of p38 MAPK signaling in this process, we tested the hypotheses that inducing plantaris tendon growth through the ablation of the synergist Achilles tendon would result in rapid expansion of a neotendon matrix surrounding the original tendon, and that treatment with the p38 MAPK inhibitor SB203580 would prevent this growth. Rats were treated with vehicle or SB203580, and subjected to synergist ablation by bilateral tenectomy of the Achilles tendon. Changes in histological and biochemical properties of plantaris tendons were analyzed 3, 7, or 28 days after overload, and comparisons were made to non-overloaded animals. By 28 days after overload, tendon mass had increased by 30% compared to non-overloaded samples, and cross-sectional area (CSA) increased by around 50%, with most of the change occurring in the neotendon. The expansion in CSA initially occurred through the synthesis of a hyaluronic acid rich matrix that was progressively replaced with mature collagen. Pericytes were present in areas of active tendon growth, but never in the original tendon ECM. Inhibition of p38 MAPK resulted in a profound decrease in IL6 expression, and had a modest effect on the expression of other ECM and cell proliferation genes, but had a negligible impact on overall tendon growth. The combined results from this study provided novel insights into tendon mechanobiology, and suggest that p38 MAPK signaling does not appear to be necessary for tendon growth in vivo. PMID:25768932

  17. Thymoquinone prevents RANKL-induced osteoclastogenesis activation and osteolysis in an in vivo model of inflammation by suppressing NF-KB and MAPK Signalling.

    PubMed

    Thummuri, Dinesh; Jeengar, Manish Kumar; Shrivastava, Shweta; Nemani, Harishankar; Ramavat, Ravindar Naik; Chaudhari, Pradip; Naidu, V G M

    2015-09-01

    Osteoclasts are multinuclear giant cells responsible for bone resorption in inflammatory bone diseases such as osteoporosis, rheumatoid arthritis and periodontitis. Because of deleterious side effects with currently available drugs the search continues for novel effective and safe therapies. Thymoquinone (TQ), the major bioactive component of Nigella sativa has been investigated for its anti-inflammatory, antioxidant and anticancer activities. However, its effects in osteoclastogenesis have not been reported. In the present study we show for the first time that TQ inhibits nuclear factor-KB ligand (RANKL) induced osteoclastogenesis in RAW 264.7 and primary bone marrow derived macrophages (BMMs) cells. RANKL induced osteoclastogenesis is associated with increased expression of multiple transcription factors via activation of NF-KB, MAPKs signalling and reactive oxygen species (ROS). Mechanistically TQ blocked the RANKL induced NF-KB activation by attenuating the phosphorylation of IkB kinase (IKKα/β). Interestingly, in RAW 264.7 cells TQ inhibited the RANKL induced phosphorylation of MAPKs and mRNA expression of osteoclastic specific genes such as TRAP, DC-STAMP, NFATc1 and c-Fos. In addition, TQ also decreased the RANKL stimulated ROS generation in macropahges (RAW 264.7) and H2O2 induced ROS generation in osteoblasts (MC-3T3-E1). Consistent with in vitro results, TQ inhibited lipopolysaccharide (LPS) induced bone resorption by suppressing the osteoclastogenesis. Indeed, micro-CT analysis showed that bone mineral density (BMD) and bone architecture parameters were positively modulated by TQ. Taken together our data demonstrate that TQ has antiosteoclastogenic effect by inhibiting inflammation induced activation of MAPKs, NF-KB and ROS generation followed by suppressing the gene expression of c-Fos and NFATc1 in osteoclast precursors.

  18. Correlation of prolactin levels and PRL-receptor expression with Stat and Mapk cell signaling in the prostate of long-term sexually active rats.

    PubMed

    Rojas-Durán, Fausto; Pascual-Mathey, Luz I; Serrano, Karina; Aranda-Abreu, Gonzalo E; Manzo, Jorge; Soto-Cid, Abraham H; Hernandez, Ma Elena

    2015-01-01

    Prolactin (PRL) is a key hormone for prostate function, with a basal level in serum and associated with two characteristic circadian peaks. In the male rat, the execution of one bout of sexual behavior with consecutive ejaculations produces a significant transient increase in PRL. However, the impact of a constant sexual life on both PRL levels and prostate function is unknown. Thus, by using constantly copulating males we analyzed the levels of serum PRL, the effect on prostate PRL receptors, and activation of pStat3, pStat5 and Mapk signaling pathways. Sexually experienced Wistar male rats were used, which underwent periodic sessions of sexual behavior tests. Males were subjected to a session of sexual behavior to achieve at least one and up to four ejaculations. Of these, a blood sample was collected from randomly selected males and the ventral prostate was removed for analysis. Serum PRL was quantified, the mRNA for PRL receptors was determined, and signaling pathways were analyzed. Data show that a constant sexual life produced a constant elevation of PRL in serum during four consecutive ejaculations. The ventral prostate showed a different mRNA expression profile for the long and short isoform of the PRL receptor, and both mRNA levels increased. Although the gland did not show modification of the activation of the pStat5 signaling pathway, the levels of pStat3 increased, and the Mapk pathway showed one significant elevation after the third ejaculation. Thus, we showed that an active and constant sexual life produces a sustained increase in serum PRL, its receptors, and the pStat3 signaling pathway. These responses seem to underlie the required physiological need to produce the quantity and quality of prostatic semen to ensure the appropriate environment for sperm to reach and fertilize the ovum.

  19. Flavonoids Identified from Korean Scutellaria baicalensis Georgi Inhibit Inflammatory Signaling by Suppressing Activation of NF-κB and MAPK in RAW 264.7 Cells

    PubMed Central

    Hong, Gyeong-Eun; Kim, Jin-A.; Nagappan, Arulkumar; Yumnam, Silvia; Lee, Ho-Jeong; Kim, Eun-Hee; Lee, Won-Sup; Shin, Sung-Chul; Park, Hyeon-Soo; Kim, Gon-Sup

    2013-01-01

    Scutellaria baicalensis Georgi has been used as traditional medicine for treating inflammatory diseases, hepatitis, tumors, and diarrhea in Asia. Hence, we investigated the anti-inflammatory effect and determined the molecular mechanism of action of flavonoids isolated from Korean S. baicalensis G. in lipopolysaccharide- (LPS-) stimulated RAW 264.7 macrophages. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to examine cytotoxicity of the flavonoids at various concentrations of 10, 40, 70, and 100 µg/mL. No cytotoxicity was observed in RAW 264.7 cells at these concentrations. Furthermore, the flavonoids decreased production of inflammatory mediators such as inducible nitric oxide synthase, cyclooxygenase-2, interleukin-6, and tumor necrosis factor-alpha and inhibited phosphorylation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) in LPS-induced RAW 264.7 cells. Moreover, to identify the differentially expressed proteins in RAW 264.7 cells of the control, LPS-treated, and flavonoid-treated groups, two-dimensional gel electrophoresis and mass spectrometry were conducted. The identified proteins were involved in the inflammatory response and included PRKA anchor protein and heat shock protein 70 kD. These findings suggest that the flavonoids isolated from S. baicalensis G. might have anti-inflammatory effects that regulate the expression of inflammatory mediators by inhibiting the NF-κB signaling pathway via the MAPK signaling pathway in RAW 264.7 cells. PMID:24348728

  20. Regulation of cross-talk in yeast MAPK signaling pathways.

    PubMed

    Saito, Haruo

    2010-12-01

    MAP kinase (MAPK) modules are conserved three-kinase cascades that serve central roles in intracellular signal transduction in eukaryotic cells. MAPK pathways of different inputs and outputs use overlapping sets of signaling components. In yeast, for example, three MAPK pathways (pheromone response, filamentous growth response, and osmostress adaptation) all use the same Ste11 MAPK kinase kinase (MAPKKK). How undesirable leakage of signal, or cross-talk, is prevented between these pathways has been a subject of intensive study. This review discusses recent findings from yeast that indicate that there is no single mechanism, but that a combination of four general strategies (docking interactions, scaffold proteins, cross-pathway inhibition, and kinetic insulation) are utilized for the prevention of cross-talk between any two MAPK modules.

  1. Suppression of extracellular signal-related kinase and activation of p38 MAPK are two critical events leading to caspase-8- and mitochondria-mediated cell death in phytosphingosine-treated human cancer cells.

    PubMed

    Park, Moon-Taek; Choi, Jung-A; Kim, Min-Jeong; Um, Hong-Duck; Bae, Sangwoo; Kang, Chang-Mo; Cho, Chul-Koo; Kang, Seongman; Chung, Hee Yong; Lee, Yun-Sil; Lee, Su-Jae

    2003-12-12

    We previously demonstrated that the phytosphingosine-induced apoptosis was accompanied by the concomitant induction of both the caspase-8-mediated and mitochondrial activation-mediated apoptosis pathways. In the present study, we investigated the role of mitogen-activated protein kinases (MAPKs) in the activation of these two distinct cell death pathways induced by phytosphingosine in human cancer cells. Phytosphingosine caused strong induction of caspase-8 activity and caspase-independent Bax translocation to the mitochondria. A rapid decrease of phosphorylated ERK1/2 and a marked increase of p38 MAPK phosphorylation were observed within 10 min after phytosphingosine treatment. Activation of ERK1/2 by pretreatment with phorbol 12-myristate 13-acetate or forced expression of ERK1/2 attenuated phytosphingosine-induced caspase-8 activation. However, Bax translocation and caspase-9 activation was unaffected, indicating that down-regulation of the ERK activity is specifically required for the phytosphingosine-induced caspase-8-dependent cell death pathway. On the other hand, treatment with SB203580, a p38 MAPK-specific inhibitor, or expression of a dominant negative form of p38 MAPK suppressed phytosphingosine-induced translocation of the proapoptotic protein, Bax, from the cytosol to mitochondria, cytochrome c release, and subsequent caspase-9 activation but did not affect caspase-8 activation, indicating that activation of p38 MAPK is involved in the mitochondrial activation-mediated cell death pathway. Our results suggest that phytosphingosine can utilize two different MAPK signaling pathways for amplifying the apoptosis cascade, enhancing the understanding of the molecular mechanisms utilized by naturally occurring metabolites to regulate cell death. Molecular dissection of the signaling pathways that activate the apoptotic cell death machinery is critical for both our understanding of cell death events and development of cancer therapeutic agents.

  2. Specific functions for ERK/MAPK signaling during PNS development

    PubMed Central

    Newbern, Jason M.; Li, Xiaoyan; Shoemaker, Sarah E.; Zhou, Jiang; Zhong, Jian; Wu, Yaohong; Bonder, Daniel; Hollenback, Steven; Coppola, Giovanni; Geschwind, Daniel H.; Landreth, Gary E.; Snider, William D.

    2011-01-01

    We have established functions of the stimulus dependent MAPKs, ERK1/2 and ERK5 in DRG, motor neuron, and Schwann cell development. Surprisingly, many aspects of early DRG and motor neuron development were found to be ERK1/2 independent and Erk5 deletion had no obvious effect on embryonic PNS. In contrast, Erk1/2 deletion in developing neural crest resulted in peripheral nerves that were devoid of Schwann cell progenitors, and deletion of Erk1/2 in Schwann cell precursors caused disrupted differentiation and marked hypomyelination of axons. The Schwann cell phenotypes are similar to those reported in neuregulin-1 and ErbB mutant mice and neuregulin effects could not be elicited in glial precursors lacking Erk1/2. ERK/MAPK regulation of myelination was specific to Schwann cells, as deletion in oligodendrocyte precursors did not impair myelin formation, but reduced precursor proliferation. Our data suggest a tight linkage between developmental functions of ERK/MAPK signaling and biological actions of specific RTK-activating factors. PMID:21220101

  3. Silica nanoparticles induce oxidative stress, inflammation, and endothelial dysfunction in vitro via activation of the MAPK/Nrf2 pathway and nuclear factor-κB signaling

    PubMed Central

    Guo, Caixia; Xia, Yinye; Niu, Piye; Jiang, Lizhen; Duan, Junchao; Yu, Yang; Zhou, Xianqing; Li, Yanbo; Sun, Zhiwei

    2015-01-01

    Despite the widespread application of silica nanoparticles (SiNPs) in industrial, commercial, and biomedical fields, their response to human cells has not been fully elucidated. Overall, little is known about the toxicological effects of SiNPs on the cardiovascular system. In this study, SiNPs with a 58 nm diameter were used to study their interaction with human umbilical vein endothelial cells (HUVECs). Dose- and time-dependent decrease in cell viability and damage on cell plasma-membrane integrity showed the cytotoxic potential of the SiNPs. SiNPs were found to induce oxidative stress, as evidenced by the significant elevation of reactive oxygen species generation and malondialdehyde production and downregulated activity in glutathione peroxidase. SiNPs also stimulated release of cytoprotective nitric oxide (NO) and upregulated inducible nitric oxide synthase (NOS) messenger ribonucleic acid, while downregulating endothelial NOS and ET-1 messenger ribonucleic acid, suggesting that SiNPs disturbed the NO/NOS system. SiNP-induced oxidative stress and NO/NOS imbalance resulted in endothelial dysfunction. SiNPs induced inflammation characterized by the upregulation of key inflammatory mediators, including IL-1β, IL-6, IL-8, TNFα, ICAM-1, VCAM-1, and MCP-1. In addition, SiNPs triggered the activation of the Nrf2-mediated antioxidant system, as evidenced by the induction of nuclear factor-κB and MAPK pathway activation. Our findings demonstrated that SiNPs could induce oxidative stress, inflammation, and NO/NOS system imbalance, and eventually lead to endothelial dysfunction via activation of the MAPK/Nrf2 pathway and nuclear factor-κB signaling. This study indicated a potential deleterious effect of SiNPs on the vascular endothelium, which warrants more careful assessment of SiNPs before their application. PMID:25759575

  4. Glutamate excitotoxicity activates the MAPK/ERK signaling pathway and induces the survival of rat hippocampal neurons in vivo.

    PubMed

    Ortuño-Sahagún, Daniel; González, Raúl Montes; Verdaguer, Ester; Huerta, Verónica Chaparro; Torres-Mendoza, Blanca M; Lemus, Lourdes; Rivera-Cervantes, Martha Catalina; Camins, A; Zárate, C Beas

    2014-03-01

    Current knowledge concerning the molecular mechanisms of the cellular response to excitotoxic insults in neurodegenerative diseases is insufficient. Although glutamate (Glu) has been widely studied as the main excitatory neurotransmitter and principal excitotoxic agent, the neuroprotective response enacted by neurons is not yet completely understood. Some of the molecular participants have been revealed, but the signaling pathways involved in this protective response are just beginning to be identified. Here, we demonstrate in vivo that, in response to the cell damage and death induced by Glu excitotoxicity, neurons orchestrate a survival response through the extracellular signal-regulated kinase (ERK) signaling pathway by increasing ERK expression in the rat hippocampal (CA1) region, allowing increased neuronal survival. In addition, this protective response is specifically reversed by U0126, an ERK inhibitor, which promotes cell death only when it is administered together with Glu. Our findings demonstrate that the ERK signaling pathway has a neuroprotective role in the response to Glu-induced excitotoxicity in hippocampal neurons. Therefore, the ERK signaling pathway may be activated as a cellular response to excitotoxic injury to prevent damage and neural loss, representing a novel therapeutic target in the treatment of neurodegenerative diseases.

  5. MAPK activation by radio waves

    PubMed Central

    Arthur, J. Simon C.

    2007-01-01

    In this issue of the Biochemical Journal, Freidman et al. report the findings of a study to look at the potential of mobile phones to activate intracellular signalling cascades. They found that radio waves corresponding to the frequency commonly used by mobile phones are able to activate ERK1/2 (extracellular-signal-regulated kinases 1 and 2). This effect was observed even at intensities lower than those emitted by mobile phones that are unable to cause any measurable heating effects. This study provides evidence that radio waves induce ERK1/2 activation downstream of the EGF (epidermal growth factor) receptor, which is in turn activated by the release of reactive oxygen species. PMID:17623008

  6. MAPK activation by radio waves.

    PubMed

    Arthur, J Simon C

    2007-08-01

    In this issue of the Biochemical Journal, Freidman et al. report the findings of a study to look at the potential of mobile phones to activate intracellular signalling cascades. They found that radio waves corresponding to the frequency commonly used by mobile phones are able to activate ERK1/2 (extracellular-signal-regulated kinases 1 and 2). This effect was observed even at intensities lower than those emitted by mobile phones that are unable to cause any measurable heating effects. This study provides evidence that radio waves induce ERK1/2 activation downstream of the EGF (epidermal growth factor) receptor, which is in turn activated by the release of reactive oxygen species.

  7. Relaxation oscillations and hierarchy of feedbacks in MAPK signaling

    PubMed Central

    Kochańczyk, Marek; Kocieniewski, Paweł; Kozłowska, Emilia; Jaruszewicz-Błońska, Joanna; Sparta, Breanne; Pargett, Michael; Albeck, John G.; Hlavacek, William S.; Lipniacki, Tomasz

    2017-01-01

    We formulated a computational model for a MAPK signaling cascade downstream of the EGF receptor to investigate how interlinked positive and negative feedback loops process EGF signals into ERK pulses of constant amplitude but dose-dependent duration and frequency. A positive feedback loop involving RAS and SOS, which leads to bistability and allows for switch-like responses to inputs, is nested within a negative feedback loop that encompasses RAS and RAF, MEK, and ERK that inhibits SOS via phosphorylation. This negative feedback, operating on a longer time scale, changes switch-like behavior into oscillations having a period of 1 hour or longer. Two auxiliary negative feedback loops, from ERK to MEK and RAF, placed downstream of the positive feedback, shape the temporal ERK activity profile but are dispensable for oscillations. Thus, the positive feedback introduces a hierarchy among negative feedback loops, such that the effect of a negative feedback depends on its position with respect to the positive feedback loop. Furthermore, a combination of the fast positive feedback involving slow-diffusing membrane components with slower negative feedbacks involving faster diffusing cytoplasmic components leads to local excitation/global inhibition dynamics, which allows the MAPK cascade to transmit paracrine EGF signals into spatially non-uniform ERK activity pulses. PMID:28045041

  8. Relaxation oscillations and hierarchy of feedbacks in MAPK signaling

    NASA Astrophysics Data System (ADS)

    Kochańczyk, Marek; Kocieniewski, Paweł; Kozłowska, Emilia; Jaruszewicz-Błońska, Joanna; Sparta, Breanne; Pargett, Michael; Albeck, John G.; Hlavacek, William S.; Lipniacki, Tomasz

    2017-01-01

    We formulated a computational model for a MAPK signaling cascade downstream of the EGF receptor to investigate how interlinked positive and negative feedback loops process EGF signals into ERK pulses of constant amplitude but dose-dependent duration and frequency. A positive feedback loop involving RAS and SOS, which leads to bistability and allows for switch-like responses to inputs, is nested within a negative feedback loop that encompasses RAS and RAF, MEK, and ERK that inhibits SOS via phosphorylation. This negative feedback, operating on a longer time scale, changes switch-like behavior into oscillations having a period of 1 hour or longer. Two auxiliary negative feedback loops, from ERK to MEK and RAF, placed downstream of the positive feedback, shape the temporal ERK activity profile but are dispensable for oscillations. Thus, the positive feedback introduces a hierarchy among negative feedback loops, such that the effect of a negative feedback depends on its position with respect to the positive feedback loop. Furthermore, a combination of the fast positive feedback involving slow-diffusing membrane components with slower negative feedbacks involving faster diffusing cytoplasmic components leads to local excitation/global inhibition dynamics, which allows the MAPK cascade to transmit paracrine EGF signals into spatially non-uniform ERK activity pulses.

  9. Transmembrane/cytoplasmic, rather than catalytic, domains of Mmp14 signal to MAPK activation and mammary branching morphogenesis via binding to integrin β1

    PubMed Central

    Mori, Hidetoshi; Lo, Alvin T.; Inman, Jamie L.; Alcaraz, Jordi; Ghajar, Cyrus M.; Mott, Joni D.; Nelson, Celeste M.; Chen, Connie S.; Zhang, Hui; Bascom, Jamie L.; Seiki, Motoharu; Bissell, Mina J.

    2013-01-01

    Epithelial cell invasion through the extracellular matrix (ECM) is a crucial step in branching morphogenesis. The mechanisms by which the mammary epithelium integrates cues from the ECM with intracellular signaling in order to coordinate invasion through the stroma to make the mammary tree are poorly understood. Because the cell membrane-bound matrix metalloproteinase Mmp14 is known to play a key role in cancer cell invasion, we hypothesized that it could also be centrally involved in integrating signals for mammary epithelial cells (MECs) to navigate the collagen 1 (CL-1)-rich stroma of the mammary gland. Expression studies in nulliparous mice that carry a NLS-lacZ transgene downstream of the Mmp14 promoter revealed that Mmp14 is expressed in MECs at the tips of the branches. Using both mammary organoids and 3D organotypic cultures, we show that MMP activity is necessary for invasion through dense CL-1 (3 mg/ml) gels, but dispensable for MEC branching in sparse CL-1 (1 mg/ml) gels. Surprisingly, however, Mmp14 without its catalytic activity was still necessary for branching. Silencing Mmp14 prevented cell invasion through CL-1 and disrupted branching altogether; it also reduced integrin β1 (Itgb1) levels and attenuated MAPK signaling, disrupting Itgb1-dependent invasion/branching within CL-1 gels. FRET imaging revealed that Mmp14 associates directly with Itgb1. We identified a domain of Mmp14 that is required for modulating the levels of Itgb1, MEC signaling and the rate of invasion within CL-1. These results shed light on hitherto undescribed non-proteolytic activities of Mmp14 that are necessary for the Itgb1-dependent biochemical and mechanical signals that regulate branching in the mammary epithelium. PMID:23250208

  10. Epidermal growth factor-like domain 7 promotes migration and invasion of human trophoblast cells through activation of MAPK, PI3K and NOTCH signaling pathways.

    PubMed

    Massimiani, M; Vecchione, L; Piccirilli, D; Spitalieri, P; Amati, F; Salvi, S; Ferrazzani, S; Stuhlmann, H; Campagnolo, L

    2015-05-01

    Epidermal growth factor-like domain 7 (Egfl7) is a gene that encodes a partially secreted protein and whose expression is largely restricted to the endothelia. We recently reported that EGFL7 is also expressed by trophoblast cells in mouse and human placentas. Here, we investigated the molecular pathways that are regulated by EGFL7 in trophoblast cells. Stable EGFL7 overexpression in a Jeg3 human choriocarcinoma cell line resulted in significantly increased cell migration and invasiveness, while cell proliferation was unaffected. Analysis of mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways showed that EGFL7 promotes Jeg3 cell motility by activating both pathways. We show that EGFL7 activates the epidermal growth factor receptor (EGFR) in Jeg3 cells, resulting in downstream activation of extracellular regulated kinases (ERKs). In addition, we provide evidence that EGFL7-triggered migration of Jeg3 cells involves activation of NOTCH signaling. EGFL7 and NOTCH1 are co-expressed in Jeg3 cells, and blocking of NOTCH activation abrogates enhanced migration of Jeg3 cells overexpressing EGFL7. We also demonstrate that signaling through EGFR and NOTCH converged to mediate EGFL7 effects. Reduction of endogenous EGFL7 expression in Jeg3 cells significantly decreased cell migration. We further confirmed that EGFL7 stimulates cell migration by using primary human first trimester trophoblast (PTB) cells overexpressing EGFL7. In conclusion, our data suggest that in trophoblast cells, EGFL7 regulates cell migration and invasion by activating multiple signaling pathways. Our results provide a possible explanation for the correlation between reduced expression of EGFL7 and inadequate trophoblast invasion observed in placentopathies.

  11. Emodin ameliorates lipopolysaccharide-induced mastitis in mice by inhibiting activation of NF-κB and MAPKs signal pathways.

    PubMed

    Li, Depeng; Zhang, Naisheng; Cao, Yongguo; Zhang, Wen; Su, Gaoli; Sun, Yong; Liu, Zhicheng; Li, Fengyang; Liang, Dejie; Liu, Bo; Guo, Mengyao; Fu, Yunhe; Zhang, Xichen; Yang, Zhengtao

    2013-04-05

    Emodin is an anthraquinone derivative from the Chinese herb Radix et Rhizoma Rhei. It has been reported that emodin possesses a number of biological properties, such as anti-inflammatory, anti-virus, anti-bacteria, anti-tumor, and immunosuppressive properties. However, the effect of emodin on mastitis is not yet known. The aim of this study was to investigate whether emodin has protective effect against lipopolysaccharide (LPS)-induced mastitis in a mouse model. The mouse model of mastitis was induced by injection of LPS through the duct of mammary gland. Emodin was administered intraperitoneally with the dose of 1, 2, and 4 mg/kg respectively 1h before and 12h after induction of LPS. Emodin significantly reduced infiltration of neutrophilic granulocyte, activation of myeloperoxidase (MPO), concentration of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6), mRNA expression levels of TNF-α, IL-1β and IL-6, which were increased in LPS-induced mouse mastitis. In addition, emodin influenced nuclear factor kappa-B signal transduction pathway by inhibiting activation of nuclear transcription factor-kappaB (NF-κB) p65 and degradation inhibitor of NF-κB α (IκBα), and emodin also influenced mitogen activated protein kinases signal transduction pathway by depression activation of p38, extracellular signal-regulated kinase (ERK), and c-jun NH2-terminal kinase (JNK). In conclusion, these results indicated that emodin could exert beneficial effects on experimental mastitis induced by LPS and may represent a novel treatment strategy for mastitis.

  12. Doxycycline Suppresses Microglial Activation by Inhibiting the p38 MAPK and NF-kB Signaling Pathways.

    PubMed

    Santa-Cecília, Flávia V; Socias, Benjamin; Ouidja, Mohand O; Sepulveda-Diaz, Julia E; Acuña, Leonardo; Silva, Rangel L; Michel, Patrick P; Del-Bel, Elaine; Cunha, Thiago M; Raisman-Vozari, Rita

    2016-05-01

    In neurodegenerative diseases, the inflammatory response is mediated by activated glial cells, mainly microglia, which are the resident immune cells of the central nervous system. Activated microglial cells release proinflammatory mediators and neurotoxic factors that are suspected to cause or exacerbate these diseases. We recently demonstrated that doxycycline protects substantia nigra dopaminergic neurons in an animal model of Parkinson's disease. This effect was associated with a reduction of microglial cell activation, which suggests that doxycycline may operate primarily as an anti-inflammatory drug. In the present study, we assessed the anti-inflammatory potential of doxycycline using lipopolysaccharide (LPS)-activated primary microglial cells in culture as a model of neuroinflammation. Doxycycline attenuated the expression of key activation markers in LPS-treated microglial cultures in a concentration-dependent manner. More specifically, doxycycline treatment lowered the expression of the microglial activation marker IBA-1 as well as the production of ROS, NO, and proinflammatory cytokines (TNF-α and IL-1β). In primary microglial cells, we also found that doxycycline inhibits LPS-induced p38 MAP kinase phosphorylation and NF-kB nuclear translocation. The present results indicate that the effect of doxycycline on LPS-induced microglial activation probably occurs via the modulation of p38 MAP kinase and NF-kB signaling pathways. These results support the idea that doxycycline may be useful in preventing or slowing the progression of PD and other neurodegenerative diseases that exhibit altered glia function.

  13. MAPK Signaling in Cardiovascular Health and Disease: Molecular Mechanisms and Therapeutic Targets

    PubMed Central

    Muslin, Anthony J.

    2009-01-01

    Intracellular mitogen-activated protein kinase (MAPK) signaling cascades likely play an important role in the pathogenesis of cardiac and vascular disease. A substantial amount of basic science research has defined many of the details of MAPK pathway organization and activation, but the role of individual signaling proteins in the pathogenesis of various cardiovascular diseases is still being elucidated. In this review, the role of the MAPKs extracellular signal-regulated kinase (ERK), C-jun N-terminal kinase (JNK) and p38 MAPK in cardiac hypertrophy, cardiac remodeling after myocardial infarction, atherosclerosis and vascular restenosis will be examined with attention paid to genetically-modified murine model systems and to the use of pharmacologic inhibitors of protein kinases. Despite the complexities of this field of research, attractive targets for pharmacological therapy are emerging. PMID:18752467

  14. Ferulic Acid Administered at Various Time Points Protects against Cerebral Infarction by Activating p38 MAPK/p90RSK/CREB/Bcl-2 Anti-Apoptotic Signaling in the Subacute Phase of Cerebral Ischemia-Reperfusion Injury in Rats

    PubMed Central

    Cheng, Chin-Yi; Tang, Nou-Ying; Kao, Shung-Te; Hsieh, Ching-Liang

    2016-01-01

    Objectives This study aimed to evaluate the effects of ferulic acid (FA) administered at various time points before or after 30 min of middle cerebral artery occlusion (MCAo) followed by 7 d of reperfusion and to examine the involvement of mitogen-activated protein kinase (MAPK) signaling pathways in the cortical penumbra. Methods FA was intravenously administered to rats at a dose of 100 mg/kg 24 h before ischemia (B-FA), 2 h before ischemia (P-FA), immediately after ischemic insult (I-FA), 2 h after reperfusion (R-FA), or 24 h after reperfusion (D-FA). Results Our study results indicated that P-FA, I-FA, and R-FA effectively reduced cerebral infarct areas and neurological deficits. P-FA, I-FA, and R-FA significantly downregulated glial fibrillary acidic protein (GFAP), mitochondrial Bax, cytochrome c, and cleaved caspase-3 expression, and effectively restored the phospho-p38 MAPK (p-p38 MAPK)/p38 MAPK ratio, phospho-90 kDa ribosomal S6 kinase (p-p90RSK) expression, phospho-Bad (p-Bad) expression, the phospho-cAMP response element-binding protein (p-CREB)/CREB ratio, the cytosolic and mitochondrial Bcl-2/Bax ratios, and the cytosolic Bcl-xL/Bax ratio in the cortical penumbra 7 d after reperfusion. SB203580, a specific inhibitor of p38 MAPK, administered 30 min prior to ischemia abrogated the downregulating effects of I-FA on cerebral infarction, and mitochondrial Bax and cleaved caspase-3 expression, and the upregulating effects of I-FA on the p-p38 MAPK/p38 MAPK ratio, p-p90RSK expression, p-Bad expression, and the p-CREB/CREB, and cytosolic and mitochondrial Bcl-2/Bax ratios. Conclusions Our study results thus indicate that P-FA, I-FA, and R-FA effectively suppress reactive astrocytosis and exert neuroprotective effects against cerebral infarction by activating p38 MAPK signaling. The regulating effects of P-FA, I-FA, and R-FA on Bax-induced apoptosis result from activation of the p38 MAPK/p90RSK/CREB/Bcl-2 signaling pathway, and eventually contribute to

  15. MAPK signaling promotes axonal degeneration by speeding the turnover of the axonal maintenance factor NMNAT2

    PubMed Central

    Walker, Lauren J; Summers, Daniel W; Sasaki, Yo; Brace, EJ; Milbrandt, Jeffrey; DiAntonio, Aaron

    2017-01-01

    Injury-induced (Wallerian) axonal degeneration is regulated via the opposing actions of pro-degenerative factors such as SARM1 and a MAPK signal and pro-survival factors, the most important of which is the NAD+ biosynthetic enzyme NMNAT2 that inhibits activation of the SARM1 pathway. Here we investigate the mechanism by which MAPK signaling facilitates axonal degeneration. We show that MAPK signaling promotes the turnover of the axonal survival factor NMNAT2 in cultured mammalian neurons as well as the Drosophila ortholog dNMNAT in motoneurons. The increased levels of NMNAT2 are required for the axonal protection caused by loss of MAPK signaling. Regulation of NMNAT2 by MAPK signaling does not require SARM1, and so cannot be downstream of SARM1. Hence, pro-degenerative MAPK signaling functions upstream of SARM1 by limiting the levels of the essential axonal survival factor NMNAT2 to promote injury-dependent SARM1 activation. These findings are consistent with a linear molecular pathway for the axonal degeneration program. DOI: http://dx.doi.org/10.7554/eLife.22540.001 PMID:28095293

  16. ROS mediated MAPK signaling in abiotic and biotic stress- striking similarities and differences

    PubMed Central

    Jalmi, Siddhi K.; Sinha, Alok K.

    2015-01-01

    Plants encounter a number of environmental stresses throughout their life cycles, most of which activate mitogen activated protein kinase (MAPK) pathway. The MAPKs show crosstalks at several points but the activation and the final response is known to be specific for particular stimuli that in-turn activates specific set of downstream targets. Interestingly, reactive oxygen species (ROS) is an important and common messenger produced in various environmental stresses and is known to activate many of the MAPKs. ROS activates a similar MAPK in different environmental stimuli, showing different downstream targets with different and specific responses. In animals and yeast, the mechanism behind the specific activation of MAPK by different concentration and species of ROS is elaborated, but in plants this aspect is still unclear. This review mainly focuses on the aspect of specificity of ROS mediated MAPK activation. Attempts have been made to review the involvement of ROS in abiotic stress mediated MAPK signaling and how it differentiates with that of biotic stress. PMID:26442079

  17. Anti-tumor activity of SL4 against breast cancer cells: induction of G2/M arrest through modulation of the MAPK-dependent p21 signaling pathway

    PubMed Central

    Wang, Li-Hui; Jiang, Xiao-Rui; Chen, Guo-Liang; Guo, Wei; Zhang, Jing-Yuan; Cui, Li-Juan; Li, Hua-Huan; Li, Meng; Liu, Xing; Yang, Jing-Yu; Wu, Chun-Fu

    2016-01-01

    SL4, a chalcone-based compound, has been shown to retard tumor invasion and angiogenesis by suppressing HIF1 activity and to induce apoptosis by promoting ROS release. Here, we report that SL4 is able to inhibit the proliferation of different types of breast cancer cell in vitro and in vivo by inducing G2/M cell cycle arrest. Our results showed that SL4 exhibited strong anti-proliferative activity in several human breast cancer cell lines, with IC50 values lower than 1.3 μM. Further studies indicated that SL4 induced G2/M arrest in these cell lines. Mechanistically, SL4 reduces the expression of cyclin A2 and cdc25C and decreases the activity of the cdc2/cyclin B1 complex. Notably, SL4 treatment resulted in an obvious increase in p21 mRNA and protein levels through activation of MAPK signaling pathways, but not the TGF-β pathway. SP600125 and PD98059, specific inhibitors of JNK kinase and ERK kinase, significantly blocked the SL4-induced G2/M phase arrest and upregulation of p21. Furthermore, SL4 suppressed the growth of established breast tumors in nude mice through upregulation of p21 and downregulation of cdc25C, and displayed a good safety profile. Taken together, these findings demonstrate the potential value of SL4 as a novel multi-target anti-tumor drug candidate. PMID:27819344

  18. Protein kinase Cα suppresses Kras-mediated lung tumor formation through activation of a p38 MAPK-TGFβ signaling axis

    PubMed Central

    Hill, KS; Erdogan, E; Khoor, A; Walsh, MP; Leitges, M; Murray, NR; Fields, AP

    2014-01-01

    Protein kinase C alpha (PKCα) can activate both pro- and anti-tumorigenic signaling depending upon cellular context. Here, we investigated the role of PKCα in lung tumorigenesis in vivo. Gene expression data sets revealed that primary human non-small lung cancers (NSCLC) express significantly decreased PKCα levels, indicating that loss of PKCα expression is a recurrent event in NSCLC. We evaluated the functional relevance of PKCα loss during lung tumorigenesis in three murine lung adenocarcinoma models (LSL-Kras, LA2-Kras and urethane exposure). Genetic deletion of PKCα resulted in a significant increase in lung tumor number, size, burden and grade, bypass of oncogene-induced senescence, progression from adenoma to carcinoma and a significant decrease in survival in vivo. The tumor promoting effect of PKCα loss was reflected in enhanced Kras-mediated expansion of bronchio-alveolar stem cells (BASCs), putative tumor-initiating cells, both in vitro and in vivo. LSL-Kras/Prkca−/− mice exhibited a decrease in phospho-p38 MAPK in BASCs in vitro and in tumors in vivo, and treatment of LSL-Kras BASCs with a p38 inhibitor resulted in increased colony size indistinguishable from that observed in LSL-Kras/Prkca−/− BASCs. In addition, LSL-Kras/Prkca−/− BASCs exhibited a modest but reproducible increase in TGFβ1 mRNA, and addition of exogenous TGFβ1 to LSL-Kras BASCs results in enhanced growth similar to untreated BASCs from LSL-Kras/Prkca−/− mice. Conversely, a TGFβR1 inhibitor reversed the effects of PKCα loss in LSL-Kras/Prkca−/−BASCs. Finally, we identified the inhibitors of DNA binding (Id) Id1–3 and the Wilm’s Tumor 1 as potential downstream targets of PKCα-dependent tumor suppressor activity in vitro and in vivo. We conclude that PKCα suppresses tumor initiation and progression, at least in part, through a PKCα-p38MAPK-TGFβ signaling axis that regulates tumor cell proliferation and Kras-induced senescence. Our results provide the

  19. EGFR/MAPK signaling regulates the proliferation of Drosophila renal and nephric stem cells.

    PubMed

    Li, Zhouhua; Liu, Sen; Cai, Yu

    2015-01-20

    Tissue homeostasis, accomplished through the self-renewal and differentiation of resident stem cells, is critical for the maintenance of adult tissues throughout an animal's lifetime. Adult Drosophila Malpighian tubules (MTs or fly kidney) are maintained by renal and nephric stem cells (RNSCs) via self-renewing divisions, however, it is unclear how RNSC proliferation and differentiation are regulated. Here we show that EGFR/MAPK signaling is dispensable for RNSC maintenance, but required for RNSC proliferation in vivo. Inactivation of the EGFR/MAPK pathway blocks or greatly retards RNSC cell cycle progression; conversely, over-activation of EGFR/MAPK signaling results in RNSC over-proliferation and disrupts the normal differentiation of renablasts (RBs), the immediate daughters of RNSC divisions. Our data further suggest that EGFR/MAPK signaling functions independently of JAK/STAT signaling and that dMyc and CycE partially mediate EGFR/MAPK signaling in MTs. Together, our data suggest a principal role of EGFR/MAPK signaling in regulating RNSC proliferation, which may provide important clues for understanding mammalian kidney repair and regeneration following injury.

  20. Adenovirus infection stimulates the Raf/MAPK signaling pathway and induces interleukin-8 expression.

    PubMed Central

    Bruder, J T; Kovesdi, I

    1997-01-01

    Previous studies have shown that airway administration of adenovirus or adenovirus vectors results in a dose-dependent inflammatory response which limits the duration of transgene expression. We explored the possibility that adenovirus infection triggers signal transduction pathways that induce the synthesis of cytokines and thus contribute to the early inflammatory response. Since stimulation of the Raf/mitogen-activated protein kinase (MAPK) pathway activates transcription factors that control the expression of inflammatory cytokines, we examined the activation of this pathway following adenovirus infection. Adenovirus infection induced the rapid activation of Raf-1 and a transient increase in the tyrosine phosphorylation and activation of p42mapk at early times postinfection. Activation of the Raf/MAPK pathway by adenovirus is likely triggered by the infection process, since it occurred rapidly and with various mutant adenoviruses and adenovirus vectors. Moreover, interleukin-8 (IL-8) mRNA accumulation was evident at 20 min postinfection and was induced even in the presence of cycloheximide. Both MAPK activation and IL-8 production were inhibited by forskolin, a potent inhibitor of Raf-1. These results suggest that adenovirus-induced Raf/MAPK activation contributes to IL-8 production. Adenovirus-induced activation of the Raf/MAPK signaling pathway and IL-8 production may play critical roles in the inflammation observed following in vivo administration of adenovirus vectors for gene therapy. PMID:8985363

  1. Involvement of AP-1 in p38MAPK signaling pathway in osteoblast apoptosis induced by high glucose.

    PubMed

    Feng, Z P; Deng, H C; Jiang, R; Du, J; Cheng, D Y

    2015-04-10

    We investigated the effect of p38MAPK/AP-1 (activator protein-1) signaling on the apoptosis of osteoblasts induced by high glucose. A lentivirus vector of small hairpin RNA (shRNA) targeting p38MAPK was constructed in vitro. Osteoblasts MC3T3-E1 cultured in vitro were treated with vehicle, high glucose, p38MAPK-shRNA transfection, p38MAPK inhibitor, and unrelated shRNA transfection. Apoptosis, protein levels of p38MAPK, and activities of AP-1 in MC3T3-E1 osteoblasts were measured using TUNEL and flow cytometry, Western blot analysis, and an electrophoretic mobility shift assay. Compared with the vehicle group, high glucose induced apoptosis of MC3T3-E1 osteoblasts and activated p38MAPK and AP-1. p38MAPK-shRNA transfection blocked the effect of high glucose stimulation, and the p38MAPK inhibitor showed similar effects as those observed in p38MAPK transfection. Unrelated shRNA had no effect on these changes in MC3T3-E1 osteoblasts induced by high glucose. Therefore, our results suggest that p38MAPK-shRNA reduce apoptosis of MC3T3-E1 osteoblasts induced by high glucose by inhibiting the p38MAPK-AP-1 signaling pathway.

  2. Wogonin suppresses TNF-{alpha}-induced MMP-9 expression by blocking the NF-{kappa}B activation via MAPK signaling pathways in human aortic smooth muscle cells

    SciTech Connect

    Lee, Syng-Ook; Jeong, Yun-Jeong; Yu, Mi Hee; Lee, Ji-Won; Hwangbo, Mi Hyang; Kim, Cheorl-Ho; Lee, In-Seon . E-mail: inseon@kmu.ac.kr

    2006-12-08

    Matrix metalloproteinase-9 (MMP-9) plays a major role in the pathogenesis of atherosclerosis and restenosis by regulating both migration and proliferation of vascular smooth muscle cells (VSMC) after an arterial injury. In this study, we examined the inhibitory effect of three major flavonoids in Scutellariae Radix, baicalin, baicalein, and wogonin, on TNF-{alpha}-induced MMP-9 expression in human aortic smooth muscle cells (HASMC). Wogonin, but not baicalin and baicalein, significantly and selectively suppressed TNF-{alpha}-induced MMP-9 expression in HASMC. Reporter gene, electrophoretic mobility shift, and Western blotting assays showed that wogonin inhibits MMP-9 gene transcriptional activity by blocking the activation of NF-{kappa}B via MAPK signaling pathways. Moreover, the Matrigel migration assay showed that wogonin reduced TNF-{alpha}-induced HASMC migration. These results suggest that wogonin effectively suppresses TNF-{alpha}-induced HASMC migration through the selective inhibition of MMP-9 expression and represents a potential agent for the prevention of vascular disorders related to the migration of VSMC.

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

    PubMed Central

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

    2016-01-01

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

  4. Whole transcriptome profiling of the human hippocampus suggests an involvement of the KIBRA rs17070145 polymorphism in differential activation of the MAPK signaling pathway.

    PubMed

    Piras, I S; Krate, J; Schrauwen, I; Corneveaux, J J; Serrano, G E; Sue, L; Beach, T G; Huentelman, M J

    2017-04-05

    The rs17070145-T variant of the WWC1 gene, coding for the KIBRA protein, has been associated with both increased episodic memory performance and lowered risk for late onset Alzheimer's disease, although the mechanism behind this protective effect has not been completely elucidated. To achieve a better understanding of the pathways modulated by rs17070145 and its associated functional variant(s), we used laser capture microdissection (LCM) and RNA-sequencing to investigate the effect of rs17070145 genotypes on whole transcriptome expression in the human hippocampus (HP) of 22 neuropathologically normal individuals, with a specific focus on the dentate gyrus (DG) and at the pyramidal cells (PC) of CA1 and CA3 sub-regions. Differential expression analysis of RNA-seq data within the HP based on the rs17070145 genotype revealed an overexpression of genes involved in the MAPK signaling pathway, potentially driven by the T/T genotype. The most important contribution comes from genes dysregulated within the DG region. Other genes significantly dysregulated, and not involved in the MAPK1 pathway (Adj P < 0.01 and Fold Change > |1.00|) were: RSPO4 (HP); ARC, DUSP5, DNAJB5, EGR4, PPP1R15A, WBP11P1, EGR1, GADD45B (DG); CH25H, HSPA1A, HSPA1B, TNFSF9 and NPAS4 (PC). Several evidences suggested that the MAPK signaling pathway is linked with memory and learning processes. In non-neuronal cells, the KIBRA protein is phosphorylated by ERK1/2 (involved in the MAPK signaling) in cells as well as in vitro. Several of the other dysregulated genes are involved in memory and learning processes, as well as in Alzheimer's Disease. In conclusion, our results suggest that the effect of the WWC1 rs17070145 polymorphism on memory performance and Alzheimer's disease might be due to a differential regulation of the MAPK signaling, a key pathway involved in memory and learning processes. This article is protected by copyright. All rights reserved.

  5. MAPK signaling – a key element in plant defense response to insects

    PubMed Central

    Hettenhausen, Christian; Schuman, Meredith C.; Wu, Jianqiang

    2016-01-01

    Insects have long been the most abundant herbivores, and plants have evolved sophisticated mechanisms to defend against their attack. In particular, plants can perceive specific patterns of tissue damage associated with insect herbivory. Some plant species can perceive certain elicitors in insect oral secretions (OS) that enter wounds during feeding, and rapidly activate a series of intertwined signaling pathways to orchestrate the biosynthesis of various defensive metabolites. Mitogen-activated protein kinases (MAPKs), common to all eukaryotes, are involved in the orchestration of many cellular processes, including development and stress responses. In plants, at least two MAPKs, salicylic acid-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK), are rapidly activated by wounding or insect OS; importantly, genetic studies using transgenic or mutant plants impaired in MAPK signaling indicated that MAPKs play critical roles in regulating the herbivory-induced dynamics of phytohormones, such as jasmonic acid, ethylene, and salicylic acid, and MAPKs are also required for transcriptional activation of herbivore defense-related genes and accumulation of defensive metabolites. In this review, we summarize recent developments in understanding the functions of MAPKs in plant resistance to insect herbivores. PMID:24753304

  6. Aldosterone-induced brain MAPK signaling and sympathetic excitation are angiotensin II type-1 receptor dependent.

    PubMed

    Zhang, Zhi-Hua; Yu, Yang; Wei, Shun-Guang; Felder, Robert B

    2012-02-01

    Angiotensin II (ANG II)-induced mitogen-activated protein kinase (MAPK) signaling upregulates angiotensin II type-1 receptors (AT(1)R) in hypothalamic paraventricular nucleus (PVN) and contributes to AT(1)R-mediated sympathetic excitation in heart failure. Aldosterone has similar effects to increase AT(1)R expression in the PVN and sympathetic drive. The present study was undertaken to determine whether aldosterone also activates the sympathetic nervous system via MAPK signaling and, if so, whether its effect is independent of ANG II and AT(1)R. In anesthetized rats, a 4-h intravenous infusion of aldosterone induced increases (P < 0.05) in phosphorylated (p-) p44/42 MAPK in PVN, PVN neuronal excitation, renal sympathetic nerve activity (RSNA), mean blood pressure (MBP), and heart rate (HR). Intracerebroventricular or bilateral PVN microinjection of the p44/42 MAPK inhibitor PD-98059 reduced the aldosterone-induced RSNA, HR, and MBP responses. Intracerebroventricular pretreatment (5 days earlier) with pooled small interfering RNAs targeting p44/42 MAPK reduced total and p-p44/42 MAPK, aldosterone-induced c-Fos expression in the PVN, and the aldosterone-induced increases in RSNA, HR, and MBP. Intracerebroventricular infusion of either the mineralocorticoid receptor antagonist RU-28318 or the AT(1)R antagonist losartan blocked aldosterone-induced phosphorylation of p44/42 MAPK and prevented the increases in RSNA, HR, and MBP. These data suggest that aldosterone-induced sympathetic excitation depends upon that AT(1)R-induced MAPK signaling in the brain. The short time course of this interaction suggests a nongenomic mechanism, perhaps via an aldosterone-induced transactivation of the AT(1)R as described in peripheral tissues.

  7. Age-dependent changes of the antioxidant system in rat livers are accompanied by altered MAPK activation and a decline in motor signaling

    PubMed Central

    Yang, Wei; Burkhardt, Britta; Fischer, Luise; Beirow, Maja; Bork, Nadja; Wönne, Eva C.; Wagner, Cornelia; Husen, Bettina; Zeilinger, Katrin; Liu, Liegang; Nussler, Andreas K.

    2015-01-01

    Aging is characterized by a progressive decrease of cellular functions, because cells gradually lose their capacity to respond to injury. Increased oxidative stress is considered to be one of the major contributors to age-related changes in all organs including the liver. Our study has focused on elucidating whether important antioxidative enzymes, the mTOR pathway, and MAPKs exhibit age-dependent changes in the liver of rats during aging. We found an age-dependent increase of GSH in the cytosol and mitochondria. The aged liver showed an increased SOD enzyme activity, while the CAT enzyme activity decreased. HO-1 and NOS-2 gene expression was lower in adult rats, but up-regulated in aged rats. Western blot analysis revealed that SOD1, SOD2, GPx, GR, γ-GCL, and GSS were age-dependent up-regulated, while CAT remained constant. We also demonstrated that the phosphorylation of Akt, JNK, p38, and TSC2Ser1254 decreased while ERK1/2 and TSC2Thr1462 increased age-dependently. Furthermore, our data show that the mTOR pathway seems to be activated in livers of aged rats, and hence stimulating cell proliferation/regeneration, as confirmed by an age-dependent increase of PCNA and p-eIF4ESer209 protein expression. Our data may help to explain the fact that liver cells only proliferate in cases of necessity, like injury and damage. In summary, we have demonstrated that, age-dependent changes of the antioxidant system and stress-related signaling pathways occur in the livers of rats, which may help to better understand organ aging. PMID:27004051

  8. Knockdown of mitogen-activated protein kinase (MAPK) signalling in the midgut of Anopheles stephensi mosquitoes using antisense morpholinos.

    PubMed

    Pietri, J E; Cheung, K W; Luckhart, S

    2014-10-01

    Arthropod-borne infectious diseases are responsible for nearly 1.5 million deaths annually across the globe, with malaria responsible for >50% of these deaths. Recent efforts to enhance malaria control have focused on developing genetically modified Anopheles mosquitoes that are resistant to malaria parasite infection by manipulating proteins that are essential to the immune response. Although this approach has shown promise, the lack of efficient genetic tools in the mosquito makes it difficult to investigate innate immunity using reverse genetics. Current gene knockdown strategies based on small interfering RNA are typically labourious, inefficient, and require extensive training. In the present study, we describe the use of morpholino antisense oligomers to knockdown MEK-ERK signalling in the midgut of Anopheles stephensi through a simple feeding protocol. Anti-MEK morpholino provided in a saline meal was readily ingested by female mosquitoes with minimal toxicity and resulted in knockdown of total MEK protein levels 3-4 days after morpholino feeding. Further, anti-MEK morpholino feeding attenuated inducible phosphorylation of the downstream kinase ERK and, as predicted by previous work, reduced parasite burden in mosquitoes infected with Plasmodium falciparum. To our knowledge, this is the first example of morpholino use for target protein knockdown via feeding in an insect vector. Our results suggest this method is not only efficient for studies of individual proteins, but also for studies of phenotypic control by complex cell signalling networks. As such, our protocol is an effective alternative to current methods for gene knockdown in arthropods.

  9. Baicalin Attenuates Hypoxia-Induced Pulmonary Arterial Hypertension to Improve Hypoxic Cor Pulmonale by Reducing the Activity of the p38 MAPK Signaling Pathway and MMP-9

    PubMed Central

    Wang, Yiran; Chen, Ali; Chen, Mayun; Yao, Dan; Xu, Xiaomei; Wang, Liangxing

    2016-01-01

    Baicalin has a protective effect on hypoxia-induced pulmonary hypertension in rats, but the mechanism of this effect remains unclear. Thus, investigating the potential mechanism of this effect was the aim of the present study. Model rats that display hypoxic pulmonary hypertension and cor pulmonale under control conditions were successfully generated. We measured a series of indicators to observe the levels of pulmonary arterial hypertension, pulmonary arteriole remodeling, and right ventricular remodeling. We assessed the activation of p38 mitogen-activated protein kinase (MAPK) in the pulmonary arteriole walls and pulmonary tissue homogenates using immunohistochemistry and western blot analyses, respectively. The matrix metalloproteinase- (MMP-) 9 protein and mRNA levels in the pulmonary arteriole walls were measured using immunohistochemistry and in situ hybridization. Our results demonstrated that baicalin not only reduced p38 MAPK activation in both the pulmonary arteriole walls and tissue homogenates but also downregulated the protein and mRNA expression levels of MMP-9 in the pulmonary arteriole walls. This downregulation was accompanied by the attenuation of pulmonary hypertension, arteriole remodeling, and right ventricular remodeling. These results suggest that baicalin may attenuate pulmonary hypertension and cor pulmonale, which are induced by chronic hypoxia, by downregulating the p38 MAPK/MMP-9 pathway. PMID:27688788

  10. Baicalin Attenuates Hypoxia-Induced Pulmonary Arterial Hypertension to Improve Hypoxic Cor Pulmonale by Reducing the Activity of the p38 MAPK Signaling Pathway and MMP-9.

    PubMed

    Yan, Shuangquan; Wang, Yiran; Liu, Panpan; Chen, Ali; Chen, Mayun; Yao, Dan; Xu, Xiaomei; Wang, Liangxing; Huang, Xiaoying

    2016-01-01

    Baicalin has a protective effect on hypoxia-induced pulmonary hypertension in rats, but the mechanism of this effect remains unclear. Thus, investigating the potential mechanism of this effect was the aim of the present study. Model rats that display hypoxic pulmonary hypertension and cor pulmonale under control conditions were successfully generated. We measured a series of indicators to observe the levels of pulmonary arterial hypertension, pulmonary arteriole remodeling, and right ventricular remodeling. We assessed the activation of p38 mitogen-activated protein kinase (MAPK) in the pulmonary arteriole walls and pulmonary tissue homogenates using immunohistochemistry and western blot analyses, respectively. The matrix metalloproteinase- (MMP-) 9 protein and mRNA levels in the pulmonary arteriole walls were measured using immunohistochemistry and in situ hybridization. Our results demonstrated that baicalin not only reduced p38 MAPK activation in both the pulmonary arteriole walls and tissue homogenates but also downregulated the protein and mRNA expression levels of MMP-9 in the pulmonary arteriole walls. This downregulation was accompanied by the attenuation of pulmonary hypertension, arteriole remodeling, and right ventricular remodeling. These results suggest that baicalin may attenuate pulmonary hypertension and cor pulmonale, which are induced by chronic hypoxia, by downregulating the p38 MAPK/MMP-9 pathway.

  11. Carvacrol protects neuroblastoma SH-SY5Y cells against Fe2+-induced apoptosis by suppressing activation of MAPK/JNK-NF-κB signaling pathway

    PubMed Central

    Cui, Zhen-wen; Xie, Zheng-xing; Wang, Bao-feng; Zhong, Zhi-hong; Chen, Xiao-yan; Sun, Yu-hao; Sun, Qing-fang; Yang, Guo-yuan; Bian, Liu-guan

    2015-01-01

    Aim: Carvacrol (2-methyl-5-isopropylphenol), a phenolic monoterpene in the essential oils of the genera Origanum and Thymus, has been shown to exert a variety of therapeutic effects. Here we examined whether carvacrol protected neuroblastoma SH-SY5Y cells against Fe2+-induced apoptosis and explored the underlying mechanisms. Methods: Neuroblastoma SH-SY5Y cells were incubated with Fe2+ for 24 h, and the cell viability was assessed with CCK-8 assay. TUNEL assay and flow cytometric analysis were performed to evaluate cell apoptosis. The mRNA levels of pro-inflammatory cytokines and NF-κB p65 were determined using qPCR. The expression of relevant proteins was determined using Western blot analysis or immunofluorescence staining. Results: Treatment of SH-SY5Y cells with Fe2+ (50–200 μmol/L) dose-dependently decreased the cell viability, which was significantly attenuated by pretreatment with carvacrol (164 and 333 μmol/L). Treatment with Fe2+ increased the Bax level and caspase-3 activity, and decreased the Bcl-2 level, resulting in cell apoptosis. Furthermore, treatment with Fe2+ significantly increased the gene expression of IL-1β, IL-6 and TNF-α, and induced the nuclear translocation of NF-κB. Treatment with Fe2+ also significantly increased the phosphorylation of p38, ERK, JNK and IKK in the cells. Pretreatment with carvacrol significantly inhibited Fe2+-induced activation of NF-κB, expression of the pro-inflammatory cytokines, and cell apoptosis. Moreover, pretreatment with carvacrol inhibited Fe2+-induced phosphorylation of JNK and IKK, but not p38 and ERK in the cells. Conclusion: Carvacrol protects neuroblastoma SH-SY5Y cells against Fe2+-induced apoptosis, which may result from suppressing the MAPK/JNK-NF-κB signaling pathways. PMID:26592517

  12. Leptin induces osteocalcin expression in ATDC5 cells through activation of the MAPK-ERK1/2 signaling pathway

    PubMed Central

    Zhang, Jingjie; Yan, Meijun; Li, Xinhua; Ma, Bin; Jun, Lili; Wang, Shan-Jin; Tan, Jun

    2016-01-01

    Both leptin and osteocalcin have been found to affect growth-plate cartilage development through regulation of the physiologic processes of endochondral bone formation. Leptin mediates bone development and osteocalcin secreted in the late stage of osteoblast differentiation. The relationship between leptin and osteocalcin expression in the chondrogenic cells line is still not clear. Thus, the aim of this study was to explore the effect of leptin on the expression of osteocalcin in chondrocytes. We used clonal mouse chondrogenic ATDC5 cells to investigate the relationship between leptin and osteocalcin. We found that both leptin and osteocalcin expression were dynamically expressed during ATDC5 cell differentiation from 4 to 21 days. We also found that leptin significantly upregulated osteocalcin mRNA and protein levels 24 h after leptin stimulation. However, different concentrations and exposure times of osteocalcin did not affect the levels of leptin protein. Furthermore, we confirmed that leptin augmented the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) in a time-dependent manner but not p38 or AKT. Inhibition of pERK1/2 expression by a specific ERK1/2 inhibitor U0126 and a special small interfering RNA attenuated levels of leptin-induced osteocalcin expression, indicating that ERK1/2 mediates, in part, the effects of leptin on osteocalcin. Taken together, our results suggest that leptin regulates the expression of osteocalcin in growth plate chondrocytes via the ERK1/2 signaling pathway, while there is no effect on the phosphorylation of either p38 or AKT. PMID:27564111

  13. Anti-metastatic activities of Antrodia camphorata against human breast cancer cells mediated through suppression of the MAPK signaling pathway.

    PubMed

    Yang, Hsin-Ling; Kuo, Yueh-Hsiung; Tsai, Ching-Tsan; Huang, Yi-Ting; Chen, Ssu-Ching; Chang, Hsueh-Wei; Lin, Elong; Lin, Wen-Hsin; Hseu, You-Cheng

    2011-01-01

    The fermented culture broth of Antrodia camphorata (A. camphorata) has been shown to promote cell cycle arrest and apoptosis of human estrogen-nonresponsive MDA-MB-231 cells. Herein, we demonstrate that non-cytotoxic concentrations (20-80 μg/mL) of A. camphorata markedly inhibited the invasion/migration of highly metastatic MDA-MB-231 cells as shown by an in vitro transwell and a wound-healing repair assay. The results of a gelatin zymography assay showed that A. camphorata suppressed the activity of matrix metalloproteinase (MMP)-9 and urokinase plasminogen activator (uPA). Western blot results demonstrated that treatment with A. camphorata decreased the expression of MMP-9, MMP-2, uPA, uPA receptor (uPAR) and vascular endothelial growth factor (VEGF); while the expression of the endogenous inhibitors of these proteins, i.e., tissue inhibitors of MMP (TIMP-1 and TIMP-2), and plasminogen activator inhibitor (PAI)-1, increased. Further investigation revealed that A. camphorata suppressed the phosphorylation of ERK1/2, p38, and JNK1/2. A. camphorata treatment also led to a dose-dependent inhibition on NF-κB binding and activation. This is the first report confirming the anti-metastatic activity of this potentially beneficial mushroom against human breast cancer.

  14. Aurora kinase A interacts with H-Ras and potentiates Ras-MAPK signaling.

    PubMed

    Umstead, MaKendra; Xiong, Jinglin; Qi, Qi; Du, Yuhong; Fu, Haian

    2017-02-03

    In cancer, upregulated Ras promotes cellular transformation and proliferation in part through activation of oncogenic Ras-MAPK signaling. While directly inhibiting Ras has proven challenging, new insights into Ras regulation through protein-protein interactions may offer unique opportunities for therapeutic intervention. Here we report the identification and validation of Aurora kinase A (Aurora A) as a novel Ras binding protein. We demonstrate that the kinase domain of Aurora A mediates the interaction with the N-terminal domain of H-Ras. Further more, the interaction of Aurora A and H-Ras exists in a protein complex with Raf-1. We show that binding of H-Ras to Raf-1 and subsequent MAPK signaling is enhanced by Aurora A, and requires active H-Ras. Thus, the functional linkage between Aurora A and the H-Ras/Raf-1 protein complex may provide a mechanism for Aurora A's oncogenic activity through direct activation of the Ras/MAPK pathway.

  15. Systemic Regulation of RAS/MAPK Signaling by the Serotonin Metabolite 5-HIAA

    PubMed Central

    Schmid, Tobias; Snoek, L. Basten; Fröhli, Erika; van der Bent, M. Leontien; Kammenga, Jan; Hajnal, Alex

    2015-01-01

    Human cancer is caused by the interplay of mutations in oncogenes and tumor suppressor genes and inherited variations in cancer susceptibility genes. While many of the tumor initiating mutations are well characterized, the effect of genetic background variation on disease onset and progression is less understood. We have used C. elegans genetics to identify genetic modifiers of the oncogenic RAS/MAPK signaling pathway. Quantitative trait locus analysis of two highly diverged C. elegans isolates combined with allele swapping experiments identified the polymorphic monoamine oxidase A (MAOA) gene amx-2 as a negative regulator of RAS/MAPK signaling. We further show that the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), which is a product of MAOA catalysis, systemically inhibits RAS/MAPK signaling in different organs of C. elegans. Thus, MAOA activity sets a global threshold for MAPK activation by controlling 5-HIAA levels. To our knowledge, 5-HIAA is the first endogenous small molecule that acts as a systemic inhibitor of RAS/MAPK signaling. PMID:25978500

  16. Activation of p38MAPK in microglia after ischemia.

    PubMed

    Walton, K M; DiRocco, R; Bartlett, B A; Koury, E; Marcy, V R; Jarvis, B; Schaefer, E M; Bhat, R V

    1998-04-01

    p38MAPK has been implicated in the regulation of proinflammatory cytokines and apoptosis in vitro. To understand its role in neurodegeneration, we determined the time course and localization of the dually phosphorylated active form of p38MAPK in hippocampus after global forebrain ischemia. Phosphorylated p38MAPK and mitogen-activated protein kinase-activated protein 2 activity increased over 4 days after ischemia. Phosphorylated p38MAPK immunoreactivity was observed in microglia in regions adjacent to, but not in, the dying CA1 neurons. In contrast, neither c-Jun N-terminal kinase 1 nor p42/p44MAPK activity was altered after ischemia. These results provide the first evidence for localization of activated p38MAPK in the CNS and support a role for p38MAPK in the microglial response to stress.

  17. Effects of acrylonitrile on lymphocyte lipid rafts and RAS/RAF/MAPK/ERK signaling pathways.

    PubMed

    Li, X J; Li, B; Huang, J S; Shi, J M; Wang, P; Fan, W; Zhou, Y L

    2014-09-26

    Acrylonitrile (ACN) is a widely used chemical in the production of plastics, resins, nitriles, acrylic fibers, and synthetic rubber. Previous epidemiological investigations and animal studies have confirmed that ACN affects the lymphocytes and spleen. However, the immune toxicity mechanism is unknown. Lipid rafts are cell membrane structures that are rich in cholesterol and involved in cell signal transduction. The B cell lymophoma-10 (Bcl10) protein is a joint protein that is important in lymphocyte development and signal pathways. This study was conducted to examine the in vitro effects of ACN. We separated lipid rafts, and analyzed Bcl10 protein and caveolin. Western blotting was used to detect mitogen-activated protein kinase (MAPK) and phosphorylated MAPK levels. The results indicated that with increasing ACN concentration, the total amount of Bcl10 remained stable, but was concentrated mainly in part 4 to part 11 in electrophoretic band district which is high density in gradient centrifugation. Caveolin-1 was evaluated as a lipid raft marker protein; caveolin-1 content and position were relatively unchanged. Western blotting showed that in a certain range, MAPK protein was secreted at a higher level. At some ACN exposure levels, MAPK protein secretion was significantly decreased compared to the control group (P < 0.05). These results indicate that ACN can cause immune toxicity by damaging lipid raft structures, causing Bcl10 protein and lipid raft separation and restraining Ras-Raf-MAPK-extracellular signal-regulated kinase signaling pathways.

  18. Involvement of MAPK/NF-κB Signaling in the Activation of the Cholinergic Anti-Inflammatory Pathway in Experimental Colitis by Chronic Vagus Nerve Stimulation

    PubMed Central

    Sun, Peng; Zhou, Kewen; Wang, Sheng; Li, Ping; Chen, Sijuan; Lin, Guiping; Zhao, Yan; Wang, Tinghuai

    2013-01-01

    Background Autonomic nervous system dysfunction is implicated in the etiopathogenesis of inflammatory bowel diseases (IBD). Therapies that increase cardiovagal activity, such as Mind-Body interventions, are currently confirmed to be effective in clinical trials in IBD. However, a poor understanding of pathophysiological mechanisms limits the popularization of therapies in clinical practice. The aim of the present study was to explore the mechanisms of these therapies against 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats using a chronic vagus nerve stimulation model in vivo, as well as the lipopolysaccharide (LPS)-induced inflammatory response in human epithelial colorectal adenocarcinoma cells (Caco-2) by acetylcholine in vitro. Methods and Results Colitis was induced in rats with rectal instillation of TNBS, and the effect of chronic VNS (0.25 mA, 20 Hz, 500 ms) on colonic inflammation was evaluated. Inflammatory responses were assessed by disease activity index (DAI), histological scores, myeloperoxidase (MPO) activity, inducible nitric oxide synthase (iNOS), TNF-α and IL-6 production. The expression of Mitogen-activated protein kinases (MAPK) family members, IκB-α, and nuclear NF-κB p65 were studied by immunoblotting. Heart rate variability (HRV) analysis was also applied to assess the sympathetic-vagal balance. DAI, histological scores, MPO activity, iNOS, TNF-α and IL-6 levels were significantly decreased by chronic VNS. Moreover, both VNS and acetylcholine reduced the phosphorylation of MAPKs and prevented the nuclear translocation of NF-κB p65. Methyllycaconitine (MLA) only reversed the inhibitory effect on p-ERK and intranuclear NF-κB p65 expression by ACh in vitro, no significant change was observed in the expression of p-p38 MAPK or p-JNK by MLA. Conclusion Vagal activity modification contributes to the beneficial effects of the cholinergic anti-inflammatory pathway in IBD-related inflamed colonic mucosa based on the activation

  19. Expression profile of mitrogen-activated protein kinase (MAPK) signaling genes in the skeletal muscle & liver of rat with type 2 diabetes: Role in disease pathology

    PubMed Central

    Tang, Xiaoli; Deng, Libin; Xiong, Huangui; Li, Guilin; Lin, Jiari; Liu, Shuangmei; Xie, Jinyan; Liu, Jun; Kong, Fanjun; Tu, Guihua; Peng, Haiying; Liang, Shangdong

    2014-01-01

    Background & objectives: Type 2 diabetes (T2D) is characterized as hyperglycaemia caused by defects in insulin secretion, and it affects target tissues, such as skeletal muscle, liver and adipose tissue. Therefore, analyzing the changes of gene expression profiles in these tissues is important to elucidate the pathogenesis of T2D. We, therefore, measured the gene transcript alterations in liver and skeletal muscle of rat with induced T2D, to detect differentially expressed genes in liver and skeletal muscle and perform gene-annotation enrichment analysis. Methods: In the present study, skeletal muscle and liver tissue from 10 streptozotocin-induced diabetic rats and 10 control rats were analyzed using gene expression microarrays. KEGG pathways enriched by differentially expressed genes (DEGs) were identified by WebGestalt Expander and GATHER software. DEGs were validated by the method of real-time PCR and western blot. Results: From the 9,929 expressed genes across the genome, 1,305 and 997 differentially expressed genes (DEGs, P<0.01) were identified in comparisons of skeletal muscle and liver, respectively. Large numbers of DEGs (200) were common in both comparisons, which was clearly more than the predicted number (131 genes, P<0.001). For further interpretation of the gene expression data, three over-representation analysis softwares (WebGestalt, Expander and GATHER) were used. All the tools detected one KEGG pathway (MAPK signaling) and two GO (gene ontology) biological processes (response to stress and cell death), with enrichment of DEGs in both tissues. In addition, PPI (protein-protein interaction) networks constructed using human homologues not only revealed the tendency of DEGs to form a highly connected module, but also suggested a “hub” role of p38-MAPK-related genes (such as MAPK14) in the pathogenesis of T2D. Interpretation & conclusions: Our results indicated the considerably aberrant MAPK signaling in both insulin-sensitive tissues of T2D rat

  20. Novel human neutrophil agonistic properties of arsenic trioxide: involvement of p38 mitogen-activated protein kinase and/or c-jun NH2-terminal MAPK but not extracellular signal-regulated kinases-1/2.

    PubMed

    Binet, François; Girard, Denis

    2008-12-01

    Arsenic trioxide (ATO) is known for treating acute promyelocytic leukemia and for inducing apoptosis and mitogen-activated protein kinases (MAPKs) in promyelocytes and cancer cells. We recently reported that ATO induces neutrophil apoptosis. The aim of this study was to establish whether or not ATO recruits MAPKs in neutrophils, as well as to further investigate its agonistic properties. We found that ATO activates p38 and that, unlike H2O2, this response was not inhibited by exogenous catalase. Also, we demonstrated that ATO-induced p38 activation occurs before H2O2 generation and without a calcium burst. We next established that ATO recruits c-jun NH2-terminal (JNK) but not extracellular signal-regulated kinase 1 and 2 (Erk-1/2). Using pharmacological inhibitors, we found that the proapoptotic activity of ATO occurs by a MAPK-independent mechanism. In contrast, the ability of ATO to enhance adhesion, migration, phagocytosis, release, and activity of gelatinase and degranulation of secretory, specific, and gelatinase, but not azurophilic granules, is dependent upon activation of p38 and/or JNK. This is the first study establishing that ATO possesses important agonistic properties in human neutrophils. Given the central role of neutrophils in various inflammatory disorders, we propose that ATO might have broader therapeutic implications in clinics, especially for regulating inflammation.

  1. MAPK/ERK signaling pathway-induced hyper-O-GlcNAcylation enhances cancer malignancy.

    PubMed

    Zhang, Xinling; Ma, Leina; Qi, Jieqiong; Shan, Hui; Yu, Wengong; Gu, Yuchao

    2015-12-01

    Dysregulated MAPK/ERK signaling is implicated in one-third of human tumors and represents an attractive target for the development of anticancer drugs. Similarly, elevated protein O-GlcNAcylation and O-GlcNAc transferase (OGT) are detected in various cancers and serve as attractive novel cancer-specific therapeutic targets. However, the potential connection between them remains unexplored. Here, a positive correlation was found between the activated MAPK/ERK signaling and hyper-O-GlcNAcylation in various cancer types and inhibition of the MAPK/ERK signaling by 10 µM U0126 significantly decreased the expression of OGT and O-GlcNAcylation in H1299, BPH-1 and DU145 cells; then, the pathway analysis of the potential regulators of OGT obtained from the UCSC Genome Browser was done, and ten downstream targets of ERK pathway were uncovered; the following results showed that ELK1, one of the ten targets of ERK pathway, mediated ERK signaling-induced OGT upregulation; finally, the MTT assay and the soft agar assay showed that the inhibition of MAPK/ERK signaling reduced the promotion effect of hyper-O-GlcNAcylation on cancer cell proliferation and anchorage-independent growth. Taken together, our data originally provided evidence for the regulatory mechanism of hyper-O-GlcNAcylation in tumors, which will be helpful for the development of anticancer drugs targeting to hyper-O-GlcNAcylation. This study also provided a new mechanism by which MAPK/ERK signaling-enhanced cancer malignancy. Altogether, the recently discovered oncogenic factor O-GlcNAc was linked to the classical MAPK/ERK signaling which is essential for the maintenance of malignant phenotype of cancers.

  2. Persistent ERK/MAPK Activation Promotes Lactotrope Differentiation and Diminishes Tumorigenic Phenotype

    PubMed Central

    Booth, Allyson; Trudeau, Tammy; Gomez, Crystal; Lucia, M. Scott

    2014-01-01

    The signaling pathways that govern the lactotrope-specific differentiated phenotype, and those that control lactotrope proliferation in both physiological and pathological lactotrope expansion, are poorly understood. Moreover, the specific role of MAPK signaling in lactotrope proliferation vs differentiation, whether activated phosphorylated MAPK is sufficient for prolactinoma tumor formation remain unknown. Given that oncogenic Ras mutations and persistently activated phosphorylated MAPK are found in human tumors, including prolactinomas and other pituitary tumors, a better understanding of the role of MAPK in lactotrope biology is required. Here we directly examined the role of persistent Ras/MAPK signaling in differentiation, proliferation, and tumorigenesis of rat pituitary somatolactotrope GH4 cells. We stimulated Ras/MAPK signaling in a persistent, long-term manner (over 6 d) in GH4 cells using two distinct approaches: 1) a doxycycline-inducible, oncogenic V12Ras expression system; and 2) continuous addition of exogenous epidermal growth factor. We find that long-term activation of the Ras/MAPK pathway over 6 days promotes differentiation of the bihormonal somatolactotrope GH4 precursor cell into a prolactin-secreting, lactotrope cell phenotype in vitro and in vivo with GH4 cell xenograft tumors. Furthermore, we show that persistent activation of the Ras/MAPK pathway not only fails to promote cell proliferation, but also diminishes tumorigenic characteristics in GH4 cells in vitro and in vivo. These data demonstrate that activated MAPK promotes differentiation and is not sufficient to drive tumorigenesis, suggesting that pituitary lactotrope tumor cells have the ability to evade the tumorigenic fate that is often associated with Ras/MAPK activation. PMID:25361391

  3. The Dictyostelium MAPK ERK1 is phosphorylated in a secondary response to early developmental signaling.

    PubMed

    Schwebs, David J; Hadwiger, Jeffrey A

    2015-01-01

    Previous reports have suggested that the two mitogen-activated protein kinases (MAPKs) in Dictyostelium discoideum, ERK1 and ERK2, can be directly activated in response to external cAMP even though these MAPKs play different roles in the developmental life cycle. To better characterize MAPK regulation, the levels of phosphorylated MAPKs were analyzed in response to external signals. Only ERK2 was rapidly phosphorylated in response to the chemoattractants, cAMP and folate. In contrast, the phosphorylation of ERK1 occurred as a secondary or indirect response to these stimuli and this phosphorylation was enhanced by cell-cell interactions, suggesting that other external signals can activate ERK1. The phosphorylation of ERK1 or ERK2 did not require the function of the other MAPK in these responses. Folate stimulation of a chimeric population of erk1- and gα4- cells revealed that the phosphorylation of ERK1 could be mediated through an intercellular signal other than folate. Loss of ERK1 function suppressed the developmental delay and the deficiency in anterior cell localization associated with gα5- mutants suggesting that ERK1 function can be down regulated through Gα5 subunit-mediated signaling. However, no major changes in the phosphorylation of ERK1 were observed in gα5- cells suggesting that the Gα5 subunit signaling pathway does not regulate the phosphorylation of ERK1. These findings suggest that the activation of ERK1 occurs as a secondary response to chemoattractants and that other cell-cell signaling mechanisms contribute to this activation. Gα5 subunit signaling can down regulate ERK1 function to promote prestalk cell development but not through major changes to the level of phosphorylated ERK1.

  4. PKG-Mediated MAPK Signaling Is Necessary for Long-Term Operant Memory in "Aplysia"

    ERIC Educational Resources Information Center

    Michel, Maximilian; Green, Charity L.; Eskin, Arnold; Lyons, Lisa C.

    2011-01-01

    Signaling pathways necessary for memory formation, such as the mitogen-activated protein kinase (MAPK) pathway, appear highly conserved across species and paradigms. Learning that food is inedible (LFI) represents a robust form of associative, operant learning that induces short- (STM) and long-term memory (LTM) in "Aplysia." We investigated the…

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

    PubMed Central

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

    2016-01-01

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

  6. Fisetin inhibits migration and invasion of human cervical cancer cells by down-regulating urokinase plasminogen activator expression through suppressing the p38 MAPK-dependent NF-κB signaling pathway.

    PubMed

    Chou, Ruey-Hwang; Hsieh, Shu-Ching; Yu, Yung-Luen; Huang, Min-Hsien; Huang, Yi-Chang; Hsieh, Yi-Hsien

    2013-01-01

    Fisetin (3,3',4',7-tetrahydroxyflavone), a naturally occurring flavonoid, has been reported to inhibit proliferation and induce apoptosis in several cancer types. However, its effect on the anti-metastatic potential of cervical cancer cells remains unclear. In the present study, we found that fisetin inhibits the invasion and migration of cervical cancer cells. The expression and activity of urokinase plasminogen activator (uPA) was significantly suppressed by fisetin in a dose-dependent manner. We also demonstrated that fisetin reduces the phosphorylation of p38 MAPK, but not that of ERK1/2, JNK1/2, or AKT. Addition of a p38 MAPK inhibitor, SB203580, further enhanced the inhibitory effect of fisetin on the expression and activity of uPA and the invasion and motility in cervical cancer cells. Fisetin suppressed the TPA (tetradecanoylphorbol-13-acetate)-induced activation of p38 MAPK and uPA, and inhibited the TPA-enhanced migratory and invasive abilities. Furthermore, the promoter activity of the uPA gene was dramatically repressed by fisetin, which disrupted the nuclear translocation of NF-κB and its binding amount on the promoter of the uPA gene, and these suppressive effects could be further enhanced by SB203580. This study provides strong evidence for the molecular mechanism of fisetin in inhibiting the aggressive phenotypes by repression of uPA via interruption of p38 MAPK-dependent NF-κB signaling pathway in cervical cancer cells and thus contributes insight to the potential of using fisetin as a therapeutic strategy against cervical cancer by inhibiting migration and invasion.

  7. Fisetin Inhibits Migration and Invasion of Human Cervical Cancer Cells by Down-Regulating Urokinase Plasminogen Activator Expression through Suppressing the p38 MAPK-Dependent NF-κB Signaling Pathway

    PubMed Central

    Chou, Ruey-Hwang; Hsieh, Shu-Ching; Yu, Yung-Luen; Huang, Min-Hsien; Huang, Yi-Chang; Hsieh, Yi-Hsien

    2013-01-01

    Fisetin (3,3’,4’,7-tetrahydroxyflavone), a naturally occurring flavonoid, has been reported to inhibit proliferation and induce apoptosis in several cancer types. However, its effect on the anti-metastatic potential of cervical cancer cells remains unclear. In the present study, we found that fisetin inhibits the invasion and migration of cervical cancer cells. The expression and activity of urokinase plasminogen activator (uPA) was significantly suppressed by fisetin in a dose-dependent manner. We also demonstrated that fisetin reduces the phosphorylation of p38 MAPK, but not that of ERK1/2, JNK1/2, or AKT. Addition of a p38 MAPK inhibitor, SB203580, further enhanced the inhibitory effect of fisetin on the expression and activity of uPA and the invasion and motility in cervical cancer cells. Fisetin suppressed the TPA (tetradecanoylphorbol-13-acetate)-induced activation of p38 MAPK and uPA, and inhibited the TPA-enhanced migratory and invasive abilities. Furthermore, the promoter activity of the uPA gene was dramatically repressed by fisetin, which disrupted the nuclear translocation of NF-κB and its binding amount on the promoter of the uPA gene, and these suppressive effects could be further enhanced by SB203580. This study provides strong evidence for the molecular mechanism of fisetin in inhibiting the aggressive phenotypes by repression of uPA via interruption of p38 MAPK-dependent NF-κB signaling pathway in cervical cancer cells and thus contributes insight to the potential of using fisetin as a therapeutic strategy against cervical cancer by inhibiting migration and invasion. PMID:23940799

  8. The Asian-American variant of human papillomavirus type 16 exhibits higher activation of MAPK and PI3K/AKT signaling pathways, transformation, migration and invasion of primary human keratinocytes.

    PubMed

    Hochmann, Jimena; Sobrinho, João S; Villa, Luisa L; Sichero, Laura

    2016-05-01

    Asian-American (AA) HPV-16 variants are associated with higher risk of cancer. Abnormal activation of intracellular signaling play a critical role in cancer development and progression. Our aim was to elucidate mechanisms underlying the higher oncogenic potential attributed to AA variant. We evaluated activation of MAPK and PI3K/AKT pathways in primary human keratinocytes (PHKs) transduced with E6/E7 of three HPV-16 variants: E-P, AA, E-350G. Phenotypes examined included migration, anchorage independent growth and invasion. AA PHKs presented the highest levels of active proteins involved in all cascades analyzed: MAPK-ERK, MAPK-p38 and PI3K-AKT. AA PHKs were more efficient in promoting anchorage independent growth, and in stimulating cell migration and invasion. MEK1 inhibition decreased migration. The mesenchymal phenotype marker vimentin was increased in AA PHKs. Our results suggest that MEK1, ERK2, AKT2 hyperactivation influence cellular behavior by means of GSK-3b inactivation and EMT induction prompting AA immortalized PHKs to more efficiently surpass carcinogenesis steps.

  9. Pneumolysin induces cellular senescence by increasing ROS production and activation of MAPK/NF-κB signal pathway in glial cells.

    PubMed

    Kwon, Ii-Seul; Kim, Jinwook; Rhee, Dong-Kwon; Kim, Byung-Oh; Pyo, Suhkneung

    2017-02-20

    Senescence is an irreversible proliferation arrest that is induced by various stress stimuli including genotoxin. Pneumolysin (PLY) is a pathogenicity factor unique to Streptococcus pneumoniae that is important in pneumococcal-induced diseases such as otitis media, meningitis and pneumonia. However, the cell fate response to the toxin is mechanistically unclear. We investigated the effect of PLY on cellular senescence in BV-2 microglial cells. Exposure to PLY resulted in changes in the expression of phospho-p53, p21, p16, pRb and CDK2 and increased the number of senescence associated β-gal positive cells. PLY-treatment also increased PAI-1 expression and cell proliferation arrest in concentration- and time-dependent manners. PLY induced NF-κB activation and phosphorylation of SIRT-1, ERK1/2, JNK, and p38 MAPK. In addition, PLY increased the production of reactive oxygen species. Overall, the results suggest that PLY regulates microglial cellular senescence by enhancing production of reactive oxygen species, activation of MAPK and NF-κB, and phosphorylation of SIRT-1.

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

    PubMed Central

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

    2016-01-01

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

  11. Multiple crosstalk between TOR and the cell integrity MAPK signaling pathway in fission yeast

    PubMed Central

    Madrid, Marisa; Vázquez-Marín, Beatriz; Franco, Alejandro; Soto, Teresa; Vicente-Soler, Jero; Gacto, Mariano; Cansado, José

    2016-01-01

    In eukaryotic cells, the highly conserved Target of Rapamycin (TOR) and the Mitogen Activated Protein Kinase (MAPK) signaling pathways elicit adaptive responses to extra- and intracellular conditions by regulating essential cellular functions. However, the nature of the functional relationships between both pathways is not fully understood. In the fission yeast Schizosaccharomyces pombe the cell integrity MAPK pathway (CIP) regulates morphogenesis, cell wall structure and ionic homeostasis. We show that the Rab GTPase Ryh1, a TORC2 complex activator, cross-activates the CIP and its core member, the MAPK Pmk1, by two distinct mechanisms. The first one involves TORC2 and its downstream effector, Akt ortholog Gad8, which together with TORC1 target Psk1 increase protein levels of the PKC ortholog Pck2 during cell wall stress or glucose starvation. Also, Ryh1 activates Pmk1 in a TORC2-independent fashion by prompting plasma membrane trafficking and stabilization of upstream activators of the MAPK cascade, including PDK ortholog Ksg1 or Rho1 GEF Rgf1. Besides, stress-activated Pmk1 cross-inhibits Ryh1 signaling by decreasing the GTPase activation cycle, and this ensures cell growth during alterations in phosphoinositide metabolism. Our results reveal a highly intricate cross-regulatory relationship between both pathways that warrants adequate cell adaptation and survival in response to environmental changes. PMID:27876895

  12. Pseudoginsenoside-F11 (PF11) exerts anti-neuroinflammatory effects on LPS-activated microglial cells by inhibiting TLR4-mediated TAK1/IKK/NF-κB, MAPKs and Akt signaling pathways.

    PubMed

    Wang, Xiaoxiao; Wang, Chunming; Wang, Jiming; Zhao, Siqi; Zhang, Kuo; Wang, Jingmin; Zhang, Wei; Wu, Chunfu; Yang, Jingyu

    2014-04-01

    Pseudoginsenoside-F11 (PF11), an ocotillol-type ginsenoside, has been shown to possess significant neuroprotective activity. Since microglia-mediated inflammation is critical for induction of neurodegeneration, this study was designed to investigate the effect of PF11 on activated microglia. PF11 significantly suppressed the release of ROS and proinflammatory mediators induced by LPS in a microglial cell line N9 including NO, PGE2, IL-1β, IL-6 and TNF-α. Moreover, PF11 inhibited interaction and expression of TLR4 and MyD88 in LPS-activated N9 cells, resulting in an inhibition of the TAK1/IKK/NF-κB signaling pathway. PF11 also inhibited the phosphorylation of Akt and MAPKs induced by LPS in N9 cells. Importantly, PF11 significantly alleviated the death of SH-SY5Y neuroblastoma cells and primary cortical neurons induced by the conditioned-medium from activated microglia. At last, the effect of PF11 on neuroinflammation was confirmed in vivo: PF11 mitigated the microglial activation and proinflammatory factors expression obviously in both cortex and hippocampus in mice injected intrahippocampally with LPS. These findings indicate that PF11 exerts anti-neuroinflammatory effects on LPS-activated microglial cells by inhibiting TLR4-mediated TAK1/IKK/NF-κB, MAPKs and Akt signaling pathways, suggesting its therapeutic implication for neurodegenerative disease associated with neuroinflammation.

  13. Role of Ras and Mapks in TGFbeta signaling.

    PubMed

    Mulder, K M

    2000-01-01

    Normal signaling by TGFbeta, in the absence of serum or exogenous factors, involves a rapid activation of Ras, Erks, and Sapks in proliferating cultures of TGFbeta-sensitive untransformed epithelial cells and human carcinoma cells. Expression of either RasN17 or dominant-negative (DN) MKK4, or addition of the MEK1 inhibitor PD98059, can block the ability of TGFbeta to induce AP-1 complex formation at the TGFbeta(1) promoter and to autoinduce its own production. The primary components present in this TGFbeta-stimulated AP-1 complex are JunD and Fra-2, although c-Jun, and possibly Fos B, may also be present. While there are two potential Smad binding elements (SBE's) in the TGFbeta(1) promoter, supershift assays suggest that at least one of these does not bind Smad4, and the other is unable to bind factors activated by TGFbeta. In contrast, TGFbeta autoinduction is Smad3-dependent, as DN Smad3 inhibits the ability of TGFbeta to stimulate TGFbeta(1) promoter activity. Our results indicate that TGFbeta can activate both the MKK4/Sapk and MEK/Erk pathways, through Ras and TGFbeta R(I) and R(II), to induce TGFbeta(1) production; Smad4 does not appear to be involved, and Smad3 appears to function independently of this Smad4. We also demonstrate that activation of the Ras/Mapk pathway by TGFbeta positively modulates Smad1-signaling-pathway activation by TGFbeta. In addition, Smad1 could enhance TGFbeta activation of the SBE reporter SBE-luc and this effect could be blocked by co-expression of a DN TGFbeta R(I) receptor or by the MEK1 inhibitor PD98059. This cross-talk between the MEK/Erk and Smad1 pathways was mediated through the four Erk consensus phosphorylation sites in the linker region of Smad1. Mutation of these sites resulted in a loss of the ligand-dependence of both Smad1-Smad4 interactions and nuclear accumulation of Smad1, as well as a loss of the ability of Smad1 to enhance TGFbeta-mediated SBE activation. Our results provide evidence that Erk

  14. Transforming growth factor β recruits persistent MAPK signaling to regulate long-term memory consolidation in Aplysia californica.

    PubMed

    Shobe, Justin; Philips, Gary T; Carew, Thomas J

    2016-05-01

    In this study, we explore the mechanistic relationship between growth factor signaling and kinase activity that supports the protein synthesis-dependent phase of long-term memory (LTM) consolidation for sensitization ofAplysia Specifically, we examine LTM for tail shock-induced sensitization of the tail-elicited siphon withdrawal (T-SW) reflex, a form of memory that requires both (i) extracellular signal-regulated kinase (ERK1/2; MAPK) activity within identified sensory neurons (SNs) that mediate the T-SW and (ii) the activation of transforming growth factor β (TGFβ) signaling. We now report that repeated tail shocks that induce intermediate-term (ITM) and LTM for sensitization, also induce a sustained post-training phase of MAPK activity in SNs (lasting at least 1 h). We identified two mechanistically distinct phases of post-training MAPK: (i) an immediate phase that does not require ongoing protein synthesis or TGFβ signaling, and (ii) a sustained phase that requires both protein synthesis and extracellular TGFβ signaling. We find that LTM consolidation requires sustained MAPK, and is disrupted by inhibitors of protein synthesis and TGFβ signaling during the consolidation window. These results provide strong evidence that TGFβ signaling sustains MAPK activity as an essential mechanistic step for LTM consolidation.

  15. Maternal liver damage delays meiotic resumption in bovine oocytes through impairment of signalling cascades originated from low p38MAPK activity in cumulus cells.

    PubMed

    Tanaka, H; Takeo, S; Monji, Y; Kuwayama, T; Iwata, H

    2014-02-01

    The main objective of the present study is to investigate the molecular mechanism underlying the delay in progression of nuclear maturation in oocytes derived from cows with damaged livers (DL cows), which was previously reported. In present study, delayed progression of nuclear maturation of oocytes derived from DL cows relative to oocytes derived from cows with healthy livers (HL cows) was accompanied by low maturation promoting factor (MPF) activity (0.43 fold, p < 0.05). When cumulus cells were removed from cumulus-oocyte complexes and the denuded oocytes were cultured, there was no difference in the progression of nuclear maturation between the two liver conditions. In addition, gap junctional communication (GJC) between the oocyte and cumulus cells was higher in DL cows than in HL cows at 3 and 7 h of in vitro maturation (IVM) (p < 0.05). Supplementation of IVM medium with epidermal growth factor (EGF) increased the ratio of germinal vesicle breakdown (GVBD) of oocytes derived from DL cows to the level seen in oocytes derived from HL cows. Additionally, the level of p38MAPK phosphorylation at 0 h of IVM was significantly lower in cumulus cells derived from DL cows than in cumulus cells derived from HL cows (HL cows, 53.5%; DL cows, 28.9%; p < 0.05). Thus, a low level of p38MAPK phosphorylation in cumulus cells induced slow GJC closure between oocyte and cumulus cells, which resulted in slow meiotic maturation of oocytes derived from DL cows.

  16. A Novel Lipopeptide from Skin Commensal Activates TLR2/CD36-p38 MAPK Signaling to Increase Antibacterial Defense against Bacterial Infection

    PubMed Central

    Li, Dongqing; Lei, Hu; Li, Zhiheng; Li, Hongquan; Wang, Yue; Lai, Yuping

    2013-01-01

    Staphylococcus epidermidis (S.epidermidis) plays important protective roles by directly producing or by stimulating hosts to produce antimicrobial peptides (AMPs) against pathogenic infections. Although several AMPs from S.epidermidis have been identified, molecules that stimulate hosts to produce AMPs remain largly unknown. Here we demonstrate that a new lipopeptide (named LP01) purified from S.epidermidis culture media has a unique structure with heneicosanoic acid (21 carbons) binding to lysine11 of a peptide chain. In vitro LP01 increased the expression of β-defensin 2(hBD2) and hBD3 in neonatal human epidermal keratinocytes(NHEK), leading to increased capacity of cell lysates to inhibit the growth of S.aureus. In vivo LP01 induced the expression of mouse β-defensin 4(mBD4) to decrease the survival of local S.aureus in skin and systemic S.aureus survival in liver. The induction of beta-defensins by LP01 was dependent on TLR2 as Tlr2-deficient mice had decreased mBD4. Furthermore, knockdown of CD36 decreased the expression of hBD2 and hBD3, and p38 MAPK inhibitor significantly inhibited the expression of hBDs induced by LP01.Taken together, these findings demonstrate that lipopeptide LP01 from normal commensal S.epidermidis increases antimicrobial peptide hBD2 and hBD3 expression via the activation of TLR2/CD36-p38 MAPK, thus enhancing antimicrobial defense against pathogenic infections. PMID:23472173

  17. In Vitro Manganese Exposure Disrupts MAPK Signaling Pathways in Striatal and Hippocampal Slices from Immature Rats

    PubMed Central

    Peres, Tanara Vieira; Pedro, Daniela Zótico; de Cordova, Fabiano Mendes; Lopes, Mark William; Gonçalves, Filipe Marques; Mendes-de-Aguiar, Cláudia Beatriz Nedel; Walz, Roger; Farina, Marcelo; Aschner, Michael; Leal, Rodrigo Bainy

    2013-01-01

    The molecular mechanisms mediating manganese (Mn)-induced neurotoxicity, particularly in the immature central nervous system, have yet to be completely understood. In this study, we investigated whether mitogen-activated protein kinases (MAPKs) and tyrosine hydroxylase (TH) could represent potential targets of Mn in striatal and hippocampal slices obtained from immature rats (14 days old). The aim of this study was to evaluate if the MAPK pathways are modulated after subtoxic Mn exposure, which do not significantly affect cell viability. The concentrations of manganese chloride (MnCl2; 10–1,000 μM) caused no change in cell viability in slices exposed for 3 or 6 hours. However, Mn exposure significantly increased extracellular signal-regulated kinase (ERK) 1/2, as well as c-Jun N-terminal kinase (JNK) 1/2/3 phosphorylation at both 3 and 6 hours incubations, in both brain structures. Furthermore, Mn exposure did not change the total content or phosphorylation of TH at the serine 40 site in striatal slices. Thus, Mn at concentrations that do not disrupt cell viability causes activation of MAPKs (ERK1/2 and JNK1/2/3) in immature hippocampal and striatal slices. These findings suggest that altered intracellular MAPKs signaling pathways may represent an early event concerning the effects of Mn in the immature brain. PMID:24324973

  18. SlMAPK3 enhances tolerance to tomato yellow leaf curl virus (TYLCV) by regulating salicylic acid and jasmonic acid signaling in tomato (Solanum lycopersicum)

    PubMed Central

    Li, Yunzhou; Qin, Lei; Zhao, Jingjing; Muhammad, Tayeb; Cao, Hehe; Li, Hailiang; Zhang, Yan; Liang, Yan

    2017-01-01

    Several recent studies have reported on the role of mitogen-activated protein kinase (MAPK3) in plant immune responses. However, little is known about how MAPK3 functions in tomato (Solanum lycopersicum L.) infected with tomato yellow leaf curl virus (TYLCV). There is also uncertainty about the connection between plant MAPK3 and the salicylic acid (SA) and jasmonic acid (JA) defense-signaling pathways. The results of this study indicated that SlMAPK3 participates in the antiviral response against TYLCV. Tomato seedlings were inoculated with TYLCV to investigate the possible roles of SlMAPK1, SlMAPK2, and SlMAPK3 against this virus. Inoculation with TYLCV strongly induced the expression and the activity of all three genes. Silencing of SlMAPK1, SlMAPK2, and SlMAPK3 reduced tolerance to TYLCV, increased leaf H2O2 concentrations, and attenuated expression of defense-related genes after TYLCV infection, especially in SlMAPK3-silenced plants. Exogenous SA and methyl jasmonic acid (MeJA) both significantly induced SlMAPK3 expression in tomato leaves. Over-expression of SlMAPK3 increased the transcript levels of SA/JA-mediated defense-related genes (PR1, PR1b/SlLapA, SlPI-I, and SlPI-II) and enhanced tolerance to TYLCV. After TYLCV inoculation, the leaves of SlMAPK3 over-expressed plants compared with wild type plants showed less H2O2 accumulation and greater superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) activity. Overall, the results suggested that SlMAPK3 participates in the antiviral response of tomato to TYLCV, and that this process may be through either the SA or JA defense-signaling pathways. PMID:28222174

  19. BMP signaling balances murine myeloid potential through SMAD-independent p38MAPK and NOTCH pathways.

    PubMed

    Cook, Brandoch D; Evans, Todd

    2014-07-17

    Bone morphogenetic protein (BMP) signaling regulates early hematopoietic development, proceeding from mesoderm patterning through the progressive commitment and differentiation of progenitor cells. The BMP pathway signals largely through receptor-mediated activation of Mothers Against Decapentaplegic homolog (SMAD) proteins, although alternate pathways are modulated through various components of mitogen-activated protein kinase (MAPK) signaling. Using a conditional, short hairpin RNA (shRNA)-based knockdown system in the context of differentiating embryonic stem cells (ESCs), we demonstrated previously that Smad1 promotes hemangioblast specification, but then subsequently restricts primitive progenitor potential. Here we show that co-knockdown of Smad5 restores normal progenitor potential of Smad1-depleted cells, suggesting opposing functions for Smad1 and Smad5. This balance was confirmed by cotargeting Smad1/5 with a specific chemical antagonist, LDN193189 (LDN). However, we discovered that LDN treatment after hemangioblast commitment enhanced primitive myeloid potential. Moreover, inhibition with LDN (but not SMAD depletion) increased expression of Delta-like ligands Dll1 and Dll3 and NOTCH activity; abrogation of NOTCH activity restored LDN-enhanced myeloid potential back to normal, corresponding with expression levels of the myeloid master regulator, C/EBPα. LDN but not SMAD activity was also associated with activation of the p38MAPK pathway, and blocking this pathway was sufficient to enhance myelopoiesis. Therefore, NOTCH and p38MAPK pathways balance primitive myeloid progenitor output downstream of the BMP pathway.

  20. Disorders of dysregulated signal traffic through the RAS-MAPK pathway: phenotypic spectrum and molecular mechanisms

    PubMed Central

    Tartaglia, Marco; Gelb, Bruce D.

    2010-01-01

    RAS GTPases control a major signaling network implicated in several cellular functions, including cell fate determination, proliferation, survival, differentiation, migration, and senescence. Within this network, signal flow through the RAF-MEK-ERK pathway, the first identified mitogen-associated protein kinase (MAPK) cascade, mediates early and late developmental processes controlling morphology determination, organogenesis, synaptic plasticity and growth. Signaling through the RAS-MAPK cascade is tightly controlled, and its enhanced activation represents a well-known event in oncogenesis. Unexpectedly, in the past few years, inherited dysregulation of this pathway has been recognized as the cause underlying a group of clinically related disorders sharing facial dysmorphism, cardiac defects, reduced postnatal growth, ectodermal anomalies, variable cognitive deficits and susceptibility to certain malignancies as major features. These disorders are caused by heterozygosity for mutations in genes encoding RAS proteins, regulators of RAS function, modulators of RAS interaction with effectors or downstream signal transducers. Here, we provide an overview of the phenotypic spectrum associated with germline mutations perturbing RAS-MAPK signaling, the unpredicted molecular mechanisms converging towards the dysregulation of this signaling cascade, and major genotype-phenotype correlations. PMID:20958325

  1. Cannabinoids inhibit the activation of ERK MAPK in PMA/Io-stimulated mouse splenocytes.

    PubMed

    Faubert Kaplan, Barbara L; Kaminski, Norbert E

    2003-10-01

    The mechanism of action of immune suppression by cannabinoids involves suppression of interleukin-2 (IL-2) production in phorbol ester plus calcium ionophore (PMA/Io)-stimulated lymphocytes. This decrease in IL-2 was due to inhibition of activator protein-1 (AP-1) and nuclear factor of activated T cells (NF-AT) transcription factors, both of which depend on proteins that are regulated by the extracellular signal-regulated kinase subgroup of the mitogen-activated protein kinases (ERK MAPK). Thus, the objective of the present study was to characterize the effects of cannabinoid compounds on ERK MAPK under conditions where IL-2 expression was suppressed. Using the MEK inhibitor PD098059 in order to assess the role of ERK MAPK in PMA/Io-stimulated splenocytes (SPLC), it was determined that IL-2 production and expression of c-fos and c-jun nuclear protein expression depended on activation of ERK MAPK. In response to PMA/Io, expression of nuclear phosphorylated ERK MAPK was rapidly induced, peaked at approximately 15 min, and was sustained for up to 240 min. Pretreatment with cannabinol (CBN) inhibited expression of phosphorylated ERK MAPK at several time points up to 240 min post cellular activation. Furthermore, WIN-55212-2, a synthetic cannabinoid, inhibited expression of phosphorylated ERK MAPK at 240 min post cellular activation. CBN did not induce activation of ERK MAPK in the absence of PMA/Io. Collectively, these studies suggest that cannabinoid-induced inhibition of IL-2 in PMA/Io-stimulated splenocytes might be due, in part, to inhibition of ERK MAPK activation.

  2. 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 KRasG12D, a mutant that constitutively binds GTP, activates MAPK. Overexpression of KRas leads to formation of higher order Ras nanoclusters. Conversely, at lower expression levels, KRasG12D is monomeric and activates MAPK only when artificially dimerized. Moreover, dimerization and signaling of KRas are both dependent on an intact CAAX (C, cysteine; A, aliphatic; X, any amino acid) motif that is also known to mediate membrane localization. These results reveal a new, dimerization-dependent signaling mechanism of Ras, and suggest Ras dimers as a potential therapeutic target in mutant Ras-driven tumors.« less

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

    SciTech Connect

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

    2015-06-16

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

  4. Reduced signaling of PI3K-Akt and RAS-MAPK pathways is the key target for weight-loss-induced cancer prevention by dietary calorie restriction and/or physical activity.

    PubMed

    Standard, Joseph; Jiang, Yu; Yu, Miao; Su, Xiaoyu; Zhao, Zhihui; Xu, Jianteng; Chen, Jie; King, Brenee; Lu, Lizhi; Tomich, John; Baybutt, Richard; Wang, Weiqun

    2014-12-01

    Weight control through either dietary calorie restriction (DCR) or exercise has been associated with cancer prevention in animal models. However, the underlying mechanisms are not fully defined. Bioinformatics using genomics, proteomics and lipidomics was employed to elucidate the molecular targets of weight control in a mouse skin cancer model. SENCAR mice were randomly assigned into four groups for 10 weeks: ad-libitum-fed sedentary control, ad-libitum-fed exercise (AE), exercise but pair-fed isocaloric amount of control (PE) and 20% DCR. Two hours after topical TPA treatment, skin epidermis was analyzed by Affymetrix for gene expression, DIGE for proteomics and lipidomics for phospholipids. Body weights were significantly reduced in both DCR and PE but not AE mice versus the control. Among 39,000 transcripts, 411, 67 and 110 genes were significantly changed in DCR, PE and AE, respectively. The expression of genes relevant to PI3K-Akt and Ras-MAPK signaling was effectively reduced by DCR and PE but not AE as measured through GenMAPP software. Proteomics analysis identified ~120 proteins, with 27 proteins significantly changed by DCR, including up-regulated apolipoprotein A-1, a key antioxidant protein that decreases Ras-MAPK activity. Of the total 338 phospholipids analyzed by lipidomics, 57 decreased by PE including 5 phophatidylinositol species that serve as PI3K substrates. Although a full impact has not been determined yet, it appears that the reduction of both Ras-MAPK and PI3K-Akt signaling pathways is a cancer preventive target that has been consistently demonstrated by three bioinformatics approaches.

  5. Reduced signaling of PI3K-Akt and RAS-MAPK pathways are the key targets for weight loss-induced cancer prevention by dietary calorie restriction and/or physical activity

    PubMed Central

    Standard, Joseph; Jiang, Yu; Yu, Miao; Su, Xiaoyu; Zhao, Zhihui; Xu, Jianteng; Chen, Jie; King, Brenee; Lu, Lizhi; Tomich, John; Baybutt, Richard; Wang, Weiqun

    2014-01-01

    Weight control through either dietary calorie restriction (DCR) or exercise has been associated with cancer prevention in animal models. However, the underlying mechanisms are not fully defined. Bioinformatics using genomics, proteomics, and lipidomics were employed to elucidate the molecular targets of weight control in a mouse skin cancer model. SENCAR mice were randomly assigned into 4 groups for 10 weeks: ad lib-fed sedentary control, ad lib-fed exercise (AE), exercise but pair-fed isocaloric amount of control (PE), and 20% DCR. Two hours after topical TPA treatment, skin epidermis was analyzed by Affymetrix for gene expression, DIGE for proteomics, and lipidomics for phospholipids. Body weights were significantly reduced in both DCR and PE but not AE mice versus the control. Among 39,000 transcripts, 411, 67, and 110 genes were significantly changed in DCR, PE, and AE, respectively. The expression of genes relevant to PI3K-Akt and Ras-MAPK signaling was effectively reduced by DCR and PE but not AE as measured through GenMAPP software. Proteomics analysis identified ~120 proteins, with 27 proteins significantly changed by DCR, including upregulated apolipoprotein A-1, a key antioxidant protein that decreases Ras-MAPK activity. Of the total 338 phospholipids analyzed by lipidomics, 57 decreased by PE including 5 phophatidylinositol species that serve as PI3K substrates. Although a full impact has not been determined yet, it appears the reduction of both Ras-MAPK and PI3K-Akt signaling pathways are cancer preventive targets that have been consistently demonstrated by three bioinformatics approaches. PMID:25283328

  6. A p38MAPK/MK2 signaling pathway leading to redox stress, cell death and ischemia/reperfusion injury

    PubMed Central

    2014-01-01

    Background Many diseases and pathological conditions are characterized by transient or constitutive overproduction of reactive oxygen species (ROS). ROS are causal for ischemia/reperfusion (IR)-associated tissue injury (IRI), a major contributor to organ dysfunction or failure. Preventing IRI with antioxidants failed in the clinic, most likely due to the difficulty to timely and efficiently target them to the site of ROS production and action. IR is also characterized by changes in the activity of intracellular signaling molecules including the stress kinase p38MAPK. While ROS can cause the activation of p38MAPK, we recently obtained in vitro evidence that p38MAPK activation is responsible for elevated mitochondrial ROS levels, thus suggesting a role for p38MAPK upstream of ROS and their damaging effects. Results Here we identified p38MAPKα as the predominantly expressed isoform in HL-1 cardiomyocytes and siRNA-mediated knockdown demonstrated the pro-oxidant role of p38MAPKα signaling. Moreover, the knockout of the p38MAPK effector MAPKAP kinase 2 (MK2) reproduced the effect of inhibiting or knocking down p38MAPK. To translate these findings into a setting closer to the clinic a stringent kidney clamping model was used. p38MAPK activity increased upon reperfusion and p38MAPK inhibition by the inhibitor BIRB796 almost completely prevented severe functional impairment caused by IR. Histological and molecular analyses showed that protection resulted from decreased redox stress and apoptotic cell death. Conclusions These data highlight a novel and important mechanism for p38MAPK to cause IRI and suggest it as a potential therapeutic target for prevention of tissue injury. PMID:24423080

  7. Inhibition of cathepsin S confers sensitivity to methyl protodioscin in oral cancer cells via activation of p38 MAPK/JNK signaling pathways

    PubMed Central

    Hsieh, Ming-Ju; Lin, Chiao-Wen; Chen, Mu-Kuan; Chien, Su-Yu; Lo, Yu-Sheng; Chuang, Yi-Ching; Hsi, Yi-Ting; Lin, Chia-Chieh; Chen, Jui-Chieh; Yang, Shun-Fa

    2017-01-01

    Oral cancer is one of the most common cancers in the world. Approximately 90% of oral cancers are subtyped to oral squamous cell carcinoma (OSCC). Despite advances in diagnostic techniques and improvement in treatment modalities, the prognosis remains poor. Therefore, an effective chemotherapy mechanism that enhances tumor sensitivity to chemotherapeutics is urgently needed. Methyl protodioscin (MP) is a furostanol bisglycoside with a wide range of beneficial effects, including anti-inflammatory and anti-cancer properties. The aim of the present study was to determine the antitumor activity of MP on OSCC and its underlying mechanisms. Our results show that treatment of OSCC cells with MP potently inhibited cell viability. Moreover, MP leading to cell cycle arrest at G2/M phase, which subsequently activates caspase-3, -8, -9 and PARP to induce cell apoptosis. Meanwhile, we also demonstrate that MP induces a robust autophagy in OSCC cells. The results indicate cathepsin S (CTSS) is involved in MP-induced apoptosis and autophagy by modulation of p38 MAPK and JNK1/2 pathways. These findings may provide rationale to combine MP with CTSS blockade for the effective treatment of OSCC. PMID:28327651

  8. The Drosophila secreted protein Argos regulates signal transduction in the Ras/MAPK pathway.

    PubMed

    Sawamoto, K; Okabe, M; Tanimura, T; Mikoshiba, K; Nishida, Y; Okano, H

    1996-08-25

    The Drosophila argos gene encodes a secreted protein with an EGF motif which acts as an inhibitor of cellular differentiation in multiple developmental processes. To investigate the cellular pathways regulated by Argos, we screened for mutations which could modify the phenotype caused by overexpression of argos. We show that the effects of argos overexpression on the eye and wing vein development are suppressed by gain-of-function mutations of the MAPKK/D-MEK gene (Dsor1/D-mek) and the MAPK/ERK-A gene (rolled) and were enhanced by loss-of-function mutations of Star. Loss-of-function mutations in components of the Ras/MAPK signaling cascade act as dominant suppressors of the phenotype caused by the argos null mutations. A loss-of-function argos mutation enhanced the overproduction of R7 neurons caused by gain-of-function alleles of Son of sevenless and Dsor1. Conversely, overexpression of argos inhibited formation of the extra R7 cells that was caused by high-level MAPK/ERK-A activity. A phenotype of the sev; argos double mutants revealed that sev is epistatic to argos. These results provide evidence that Argos negatively regulates signal transduction events in the Ras/MAPK cascade.

  9. Gadd45 Proteins as Critical Signal Transducers Linking NF-κB to MAPK Cascades

    PubMed Central

    Yang, Z.; Song, L.; Huang, C.

    2013-01-01

    The growth arrest and DNA damage-inducible 45 (Gadd45) proteins are a group of critical signal transducers that are involved in regulations of many cellular functions. Accumulated data indicate that all three Gadd45 proteins (i.e., Gadd45α, Gadd45β, and Gadd45γ) play essential roles in connecting an upstream sensor module, the transcription Nuclear Factor-κB (NF-κB), to a transcriptional regulating module, mitogen-activated protein kinase (MAPK). This NF-κB-Gadd45(s)-MAPK pathway responds to various kinds of extracellular stimuli and regulates such cell activities as growth arrest, differentiation, cell survival, and apoptosis. Defects in this pathway can also be related to oncogenesis. In the first part of this review, the functions of Gadd45 proteins, and briefly NF-κB and MAPK, are summarized. In the second part, the mechanisms by which Gadd45 proteins are regulated by NF-κB, and how they affect MAPK activation, are reviewed. PMID:20025601

  10. Computational Modeling of PI3K/AKT and MAPK Signaling Pathways in Melanoma Cancer

    PubMed Central

    Pappalardo, Francesco; Russo, Giulia; Candido, Saverio; Pennisi, Marzio; Cavalieri, Salvatore; Motta, Santo; McCubrey, James A.; Nicoletti, Ferdinando; Libra, Massimo

    2016-01-01

    Background Malignant melanoma is an aggressive tumor of the skin and seems to be resistant to current therapeutic approaches. Melanocytic transformation is thought to occur by sequential accumulation of genetic and molecular alterations able to activate the Ras/Raf/MEK/ERK (MAPK) and/or the PI3K/AKT (AKT) signalling pathways. Specifically, mutations of B-RAF activate MAPK pathway resulting in cell cycle progression and apoptosis prevention. According to these findings, MAPK and AKT pathways may represent promising therapeutic targets for an otherwise devastating disease. Result Here we show a computational model able to simulate the main biochemical and metabolic interactions in the PI3K/AKT and MAPK pathways potentially involved in melanoma development. Overall, this computational approach may accelerate the drug discovery process and encourages the identification of novel pathway activators with consequent development of novel antioncogenic compounds to overcome tumor cell resistance to conventional therapeutic agents. The source code of the various versions of the model are available as S1 Archive. PMID:27015094

  11. CD14 Signaling Restrains Chronic Inflammation through Induction of p38-MAPK/SOCS-Dependent Tolerance

    PubMed Central

    Sahay, Bikash; Patsey, Rebeca L.; Eggers, Christian H.; Salazar, Juan C.; Radolf, Justin D.; Sellati, Timothy J.

    2009-01-01

    Current thinking emphasizes the primacy of CD14 in facilitating recognition of microbes by certain TLRs to initiate pro-inflammatory signaling events and the importance of p38-MAPK in augmenting such responses. Herein, this paradigm is challenged by demonstrating that recognition of live Borrelia burgdorferi not only triggers an inflammatory response in the absence of CD14, but one that is, in part, a consequence of altered PI3K/AKT/p38-MAPK signaling and impaired negative regulation of TLR2. CD14 deficiency results in increased localization of PI3K to lipid rafts, hyperphosphorylation of AKT, and reduced activation of p38. Such aberrant signaling leads to decreased negative regulation by SOCS1, SOCS3, and CIS, thereby compromising the induction of tolerance in macrophages and engendering more severe and persistent inflammatory responses to B. burgdorferi. Importantly, these altered signaling events and the higher cytokine production observed can be mimicked through shRNA and pharmacological inhibition of p38 activity in CD14-expressing macrophages. Perturbation of this CD14/p38-MAPK-dependent immune regulation may underlie development of infectious chronic inflammatory syndromes. PMID:20011115

  12. MicroRNAs mediated regulation of MAPK signaling pathways in chronic myeloid leukemia

    PubMed Central

    Sharma, Garima; Lee, Sang-Soo

    2016-01-01

    Chronic myeloid leukemia (CML) is a severe problem throughout the world and requires identification of novel targets for its treatment. This multifactorial disease accounts for about 15% of the all diagnosed leukemia cases. Mitogen-activated protein kinase (MAPK) signaling pathway is crucial for the cell survival and its dysregulation is being implicated in various types of cancers. In here, we have discussed the potential role of various miRNAs that are found involved in regulating the proteins cascades of MAPK signaling pathway associated with CML. An emphasis has been paid to summarize the influence of various miRNAs in elevating or suppressing the expression level of significant proteins such as miR-203, miR-196a, miR-196b, miR-30a, miR-29b, miR-138 in BCR-ABL tyrosine kinase; miR-126, miR-221, miR-128, miR-15a, miR-188-5p, miR-17 in CRK family proteins; miR-155, miR-181a with SOS proteins; miR-155, miR-19a, with KRAS proteins; miR-19a with RAF1 protein; and miR-17, miR-19a, miR-17-92 cluster with MAPK/ERK proteins. In light of ever-increasing importance and ever-widening regulatory roles of miRNAs in cells, we have reviewed the recent progress in the field of miRNAs and have tried to suggest them as controlling targets for various protein cascades of MAPK signaling pathway. An understanding of the supervisory mechanism of MAPK by miRNAs might provide novel targets for treating CML. PMID:26967056

  13. Role of the MAPKs/TGF-β1/TRAF6 signaling pathway in postoperative atrial fibrillation

    PubMed Central

    Zhang, Daoliang; Chen, Xiaoqing; Wang, Qian; Wu, Shaohui; Zheng, Yue; Liu, Xu

    2017-01-01

    Objectives To explore the relationship between the MAPKs/TGF-β1/TRAF6 signaling pathway and atrial fibrosis in patients with rheumatic heart disease (RHD) and its role in atrial fibrillation (AF) after cardiac surgery on the basis of our previous animal study of the MAPKs/TGF-β1/TRAF6 signaling pathway in atrial fibrosis. Methods A total of 57 patients with RHD without a history of AF consented to left atrial biopsy. Histopathology quantified the percentage of fibrosis, and real-time PCR and western blot assessed the mRNA and protein expression of TGF-β1, TRAF6, and connective tissue growth factor (CTGF), respectively. Western blot was also used to measure the protein expression of phosphorylated MAPKs and TGF-β-activated kinase 1 (TAK1). Serum angiotensin II (Ang II) levels were assayed using enzyme-linked immunosorbent assay (ELISA). Results Eighteen patients developed AF, whereas 39 remained in sinus rhythm (SR). The severity of atrial fibrosis was significantly higher in patients who developed AF versus those who remained in SR; the mRNA and protein expression of TGF-β1, TRAF6 and CTGF were significantly higher in patients with AF. The protein expression of phosphorylated MAPKs and TAK1 was significantly increased in patients who developed AF compared with the patients who remained in SR. Serum Ang II levels were significantly higher in patients who developed AF versus those who remained in SR. Conclusion The MAPKs/TGF-β1/TRAF6 signaling pathway is involved in atrial fibrosis in patients with RHD, which results in the occurrence of AF after cardiac surgery. PMID:28323847

  14. Hyperhomocysteinemia inhibits satellite cell regenerative capacity through p38 alpha/beta MAPK signaling.

    PubMed

    Veeranki, Sudhakar; Lominadze, David; Tyagi, Suresh C

    2015-07-15

    Chronic failure in maintenance and regeneration of skeletal muscles leads to lower muscle mass (sarcopenia), muscle weakness, and poor response to injury. Evidence suggests that aberrant p38 MAPK signaling undermines the repair process after injury in aged mice. Previous studies have shown that hyperhomocysteinemia (HHcy) has been associated with muscle weakness and lower than normal body weights. However, whether or not HHcy condition also compromises skeletal muscle regenerative capabilities is not clear. In the current study, we show that CBS-/+ mice, a model for HHcy condition, exhibited compromised regenerative function and cell proliferation upon injury. However, there was no significant difference in Pax7 expression levels in the satellite cells from CBS-/+ mouse skeletal muscles. Interestingly, the satellite cells from CBS-/+ mice not only exhibited diminished in vitro proliferative capabilities, but also there was heightened oxidative stress. In addition, there was enhanced p38 MAPK activation as well as p16 and p21 expression in the CBS-/+ mouse satellite cells. Moreover, the C2C12 myoblasts also exhibited higher p38 MAPK activation and p16 expression upon treatment with homocysteine in addition to enhanced ROS presence. Tissue engraftment potential and regeneration after injury were restored to some extent upon treatment with the p38-MAPK inhibitor, SB203580, in the CBS-/+ mice. These results together suggest that HHcy-induced diminished satellite cell proliferation involves excessive oxidative stress and p38 MAPK signaling. Our study further proposes that HHcy is a potential risk factor for elderly frailty, and need to be considered as a therapeutic target while designing the alleviation interventions/postinjury rehabilitation measures for adults with HHcy.

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

    PubMed

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

    2001-10-01

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

  16. Cyclic Compressive Stress Regulates Apoptosis in Rat Osteoblasts: Involvement of PI3K/Akt and JNK MAPK Signaling Pathways

    PubMed Central

    Jiang, Dawei; Wang, Tianchen; Zhang, Yinquan; Ma, Hui

    2016-01-01

    It is widely accepted that physiological mechanical stimulation suppresses apoptosis and induces synthesis of extracellular matrix by osteoblasts; however, the effect of stress overloading on osteoblasts has not been fully illustrated. In the present study, we investigated the effect of cyclic compressive stress on rat osteoblasts apoptosis, using a novel liquid drop method to generate mechanical stress on osteoblast monolayers. After treatment with different levels of mechanical stress, apoptosis of osteoblasts and activations of mitogen-activated protein kinases (MAPKs) and PI3-kinase (PI3K)/Akt signaling pathways were investigated. Osteoblasts apoptosis was observed after treated with specific inhibitors prior to mechanical stimulation. Protein levels of Bax/Bcl-2/caspase-3 signaling were determined using western blot with or without inhibitors of PI3K/Akt and phosphorylation of c-jun N-terminal kinase (JNK) MAPK. Results showed that mechanical stimulation led to osteoblasts apoptosis in a dose-dependent manner and a remarkable activation of MAPKs and PI3K/Akt signaling pathways. Activation of PI3K/Akt protected against apoptosis, whereas JNK MAPK increased apoptosis via regulation of Bax/Bcl-2/caspase-3 activation. In summary, the PI3K/Akt and JNK MAPK signaling pathways played opposing roles in osteoblasts apoptosis, resulting in inhibition of apoptosis upon small-magnitude stress and increased apoptosis upon large-magnitude stress. PMID:27806136

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

    PubMed

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

    2016-09-01

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

  18. Anti-oxidizing effect of the dichloromethane and hexane fractions from Orostachys japonicus in LPS-stimulated RAW 264.7 cells via upregulation of Nrf2 expression and activation of MAPK signaling pathway

    PubMed Central

    Lee, Hyeong-Seon; Lee, Gyeong-Seon; Kim, Seon-Hee; Kim, Hyun-Kyung; Suk, Dong-Hee; Lee, Dong-Seok

    2014-01-01

    Orostachys japonicus shows various biological activities. However, the molecular mechanisms remain unknown in LPS-stimulated macrophages. Here, we investigated the anti-oxidizing effect of the dichloromethane (DCM) and hexane fractions from O. japonicus (OJD and OJH) against oxidative stress in RAW 264.7 cells stimulated by LPS. OJD and OJH significantly increased the expression of heme oxygenase-1 (HO-1) in a dose- and time-dependent manner. Additionally, it was found that the expression of HO-1 was stimulated by Nrf2 activated via degradation of Keap1. ERK and p38 inhibitors repressed HO-1 induced by OJD and OJH in LPS-stimulated cells, respectively. In conclusion, these results suggest that OJD and OJH may block oxidative damage stimulated by LPS, via increasing the expression of HO-1 and Nrf2, and MAPK signaling pathway. [BMB Reports 2014; 47(2): 98-103] PMID:24219867

  19. Characterization and expression of the gene encoding En-MAPK1, an intestinal cell kinase (ICK)-like kinase activated by the autocrine pheromone-signaling loop in the Polar Ciliate, Euplotes nobilii.

    PubMed

    Candelori, Annalisa; Luporini, Pierangelo; Alimenti, Claudio; Vallesi, Adriana

    2013-04-03

    In the protozoan ciliate Euplotes, a transduction pathway resulting in a mitogenic cell growth response is activated by autocrine receptor binding of cell type-specific, water-borne signaling protein pheromones. In Euplotes raikovi, a marine species of temperate waters, this transduction pathway was previously shown to involve the phosphorylation of a nuclear protein kinase structurally similar to the intestinal-cell and male germ cell-associated kinases described in mammals. In E. nobilii, which is phylogenetically closely related to E. raikovi but inhabits Antarctic and Arctic waters, we have now characterized a gene encoding a structurally homologous kinase. The expression of this gene requires +1 translational frameshifting and a process of intron splicing for the production of the active protein, designated En-MAPK1, which contains amino acid substitutions of potential significance for cold-adaptation.

  20. How scaffolds shape MAPK signaling: what we know and opportunities for systems approaches

    PubMed Central

    Witzel, Franziska; Maddison, Louise; Blüthgen, Nils

    2012-01-01

    Scaffolding proteins add a new layer of complexity to the dynamics of cell signaling. Above their basic function to bring several components of a signaling pathway together, recent experimental research has found that scaffolds influence signaling in a much more complex way: scaffolds can exert some catalytic function, influence signaling by allosteric mechanisms, are feedback-regulated, localize signaling activity to distinct regions of the cell or increase pathway fidelity. Here we review experimental and theoretical approaches that address the function of two MAPK scaffolds, Ste5, a scaffold of the yeast mating pathway and KSR1/2, a scaffold of the classical mammalian MAPK signaling pathway. For the yeast scaffold Ste5, detailed mechanistic models have been valuable for the understanding of its function. For scaffolds in mammalian signaling, however, models have been rather generic and sketchy. For example, these models predicted narrow optimal scaffold concentrations, but when revisiting these models by assuming typical concentrations, rather a range of scaffold levels optimally supports signaling. Thus, more realistic models are needed to understand the role of scaffolds in mammalian signal transduction, which opens a big opportunity for systems biology. PMID:23267331

  1. Extracellular matrix metalloproteinase inducer enhances host resistance against pseudomonas aeruginosa infection through MAPK signaling pathway

    PubMed Central

    Li, Yongwei; Chen, Lu; Wang, Chunxia; Chen, Jianshe; Zhang, Xiaoqian; Hu, Yue; Niu, Xiaobin; Pei, Dongxu; He, Zhiqiang; Bi, Yongyi

    2016-01-01

    This study aims to explore the role of extra-cellular matrix metalloproteinase inducer (EMMPRIN) in the drug resistance of the pseudomonas aeruginosa (PA). The BALB/c mice were transfected with PA, then the mice were infected with the siRNA of EMMPRIN to silence the EMMPRIN gene. The EMMPRIN mRNA and protein were detected by using RT-PCR and western blot, respectively. In order to examine the function of EMMPRIN in drug resistance of PA, the BALB/c and C57BL/6 mice were treated with EMMPRIN siRNA. The cytokines, EMMPRIN and MMP9 were examined by the RP-PCR and ELISA, respectively, undergoing the silence of EMMPRIN siRNA. Moreover, the western blot assay was also used to test the phosphorylated MAPK in the murine macrophages after silenced by the EMMPRIN siRNA. The EMMPRIN was activated, with lipopolysaccharide stimulation and treated with the MAPK inhibitor, to evaluate whether the MAPK participates in the EMMPRIN-triggered drug resistance. The results indicated that the EMMPRIN expression was elevated in the infected BALB/c at 3 or 5 days post-infection. Silence of EMMPRIN Enhanced the Production of pro-inflammatory cytokines in PA keratitis. Silence of EMMPRIN significantly up-regulated Th1-type cytokines IFN-γ, IL-12, and IL-18, but down-regulated Th2-type cytokines IL-4, IL-5, and IL-10. MMP9 was increased in the cells with rEMMPRIN treatment. EMMPRIN inhibits pro-inflammatory cytokine production via a MAPK signaling pathway. In conclusion, EMMPRIN promotes host resistance against pseudomonas aeruginosa infection via MAPK signaling pathway. PMID:28078032

  2. Activation of Type 4 Metabotropic Glutamate Receptor Attenuates Oxidative Stress-Induced Death of Neural Stem Cells with Inhibition of JNK and p38 MAPK Signaling

    PubMed Central

    Zhang, Zhichao; Ma, Wen; Wang, Li; Gong, Hanshi; Tian, Yumei; Zhang, Jianshui; Liu, Jianxin; Lu, Haixia

    2015-01-01

    Promoting both endogenous and exogenous neural stem cells' (NSCs) survival in the hostile host environments is essential to cell replacement therapy for central nervous system (CNS) disorders. Type 4 metabotropic glutamate receptor (mGluR4), one of the members of mGluRs, has been shown to protect neurons from acute and chronic excitotoxic insults in various brain damages. The present study investigated the preventive effects of mGluR4 on NSC injury induced by oxidative stress. Under challenge with H2O2, loss of cell viability was observed in cultured rat NSCs, and treatment with selective mGluR4 agonist VU0155041 conferred protective effects against the loss of cellular viability in a concentration-dependent manner, as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Pretreatment of VU0155041 (30 μM) also inhibited the excessive NSC death induced by H2O2, and group III mGluRs antagonist (RS)-a-methylserine-O-phosphate (MSOP) or gene-targeted knockdown abolished the protective action of mGluR4, indicated by propidium iodide–Hoechst and terminal deoxynucleotidyl transferase-mediated UTP nick end labeling (TUNEL) staining. Western blot assay demonstrated that mGluR4 activation reversed the decreased procaspase-8/9/3and the destructed Bcl-2/Bax expressing balance, and likewise, MSOP and mGluR4 knockdown abrogated the action of mGluR4 activity. Furthermore, inhibition of JNK and p38 mitogen-activated protein kinases (MAPKs) were observed after mGluR4 activation, and as paralleling control, JNK-specific inhibitor SP600125 and p38-specific inhibitor SB203580 significantly rescued the H2O2-mediated NSC apoptosis and cleavage of procaspase-3. We suggest that activation of mGluR4 prevents oxidative stress-induced NSC death and apoptotic-associated protein activities with involvement of inhibiting the JNK and p38 pathways in cell culture. Our findings may help to develop strategies for enhancing the resided and transplanted NSC survival

  3. 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.

  4. Thrombin enhances NGF-mediated neurite extension via increased and sustained activation of p44/42 MAPK and p38 MAPK.

    PubMed

    Mufti, Rania E; Sarker, Krishna; Jin, Yan; Fu, Songbin; Rosales, Jesusa L; Lee, Ki-Young

    2014-01-01

    Rapid neurite remodeling is fundamental to nervous system development and plasticity. It involves neurite extension that is regulated by NGF through PI3K/AKT, p44/42 MAPK and p38 MAPK. It also involves neurite retraction that is regulated by the serine protease, thrombin. However, the intracellular signaling pathway by which thrombin causes neurite retraction is unknown. Using the PC12 neuronal cell model, we demonstrate that thrombin utilizes the PI3K/AKT pathway for neurite retraction in NGF-differentiated cells. Interestingly, however, we found that thrombin enhances NGF-induced neurite extension in differentiating cells. This is achieved through increased and sustained activation of p44/42 MAPK and p38 MAPK. Thus, thrombin elicits opposing effects in differentiated and differentiating cells through activation of distinct signaling pathways: neurite retraction in differentiated cells via PI3K/AKT, and neurite extension in differentiating cells via p44/42 MAPK and p38 MAPK. These findings, which also point to a novel cooperative role between thrombin and NGF, have significant implications in the development of the nervous system and the disease processes that afflicts it as well as in the potential of combined thrombin and NGF therapy for impaired learning and memory, and spinal cord injury which all require neurite extension and remodeling.

  5. MAPK signaling cascades mediate distinct glucocorticoid resistance mechanisms in pediatric leukemia

    PubMed Central

    Jones, Courtney L.; Gearheart, Christy M.; Fosmire, Susan; Delgado-Martin, Cristina; Evensen, Nikki A.; Bride, Karen; Waanders, Angela J.; Pais, Faye; Wang, Jinhua; Bhatla, Teena; Bitterman, Danielle S.; de Rijk, Simone R.; Bourgeois, Wallace; Dandekar, Smita; Park, Eugene; Burleson, Tamara M.; Madhusoodhan, Pillai Pallavi; Teachey, David T.; Raetz, Elizabeth A.; Hermiston, Michelle L.; Müschen, Markus; Loh, Mignon L.; Hunger, Stephen P.; Zhang, Jinghui; Garabedian, Michael J.; Porter, Christopher C.

    2015-01-01

    The outcome for pediatric acute lymphoblastic leukemia (ALL) patients who relapse is dismal. A hallmark of relapsed disease is acquired resistance to multiple chemotherapeutic agents, particularly glucocorticoids. In this study, we performed a genome-scale short hairpin RNA screen to identify mediators of prednisolone sensitivity in ALL cell lines. The incorporation of these data with an integrated analysis of relapse-specific genetic and epigenetic changes allowed us to identify the mitogen-activated protein kinase (MAPK) pathway as a mediator of prednisolone resistance in pediatric ALL. We show that knockdown of the specific MAPK pathway members MEK2 and MEK4 increased sensitivity to prednisolone through distinct mechanisms. MEK4 knockdown increased sensitivity specifically to prednisolone by increasing the levels of the glucocorticoid receptor. MEK2 knockdown increased sensitivity to all chemotherapy agents tested by increasing the levels of p53. Furthermore, we demonstrate that inhibition of MEK1/2 with trametinib increased sensitivity of ALL cells and primary samples to chemotherapy in vitro and in vivo. To confirm a role for MAPK signaling in patients with relapsed ALL, we measured the activation of the MEK1/2 target ERK in matched diagnosis-relapse primary samples and observed increased phosphorylated ERK levels at relapse. Furthermore, relapse samples have an enhanced response to MEK inhibition compared to matched diagnosis samples in xenograft models. Together, our data indicate that inhibition of the MAPK pathway increases chemosensitivity to glucocorticoids and possibly other agents and that the MAPK pathway is an attractive target for prevention and/or treatment of relapsed disease. PMID:26324703

  6. 2-O Heparan Sulfate Sulfation by Hs2st Is Required for Erk/Mapk Signalling Activation at the Mid-Gestational Mouse Telencephalic Midline.

    PubMed

    Chan, Wai Kit; Howe, Katherine; Clegg, James M; Guimond, Scott E; Price, David J; Turnbull, Jeremy E; Pratt, Thomas

    2015-01-01

    Heparan sulfate (HS) is a linear carbohydrate composed of polymerized uronate-glucosamine disaccharide units that decorates cell surface and secreted glycoproteins in the extracellular matrix. In mammals HS is subjected to differential sulfation by fifteen different heparan sulfotransferase (HST) enzymes of which Hs2st uniquely catalyzes the sulfation of the 2-O position of the uronate in HS. HS sulfation is postulated to be important for regulation of signaling pathways by facilitating the interaction of HS with signaling proteins including those of the Fibroblast Growth Factor (Fgf) family which signal through phosphorylation of extracellular signal-regulated kinases Erk1/2. In the developing mouse telencephalon Fgf2 signaling regulates proliferation and neurogenesis. Loss of Hs2st function phenocopies the thinned cerebral cortex of mutant mice in which Fgf2 or Erk1/2 function are abrogated, suggesting the hypothesis that 2-O-sulfated HS structures play a specific role in Fgf2/Erk signaling pathway in this context in vivo. This study investigated the molecular role of 2-O sulfation in Fgf2/Erk signaling in the developing telencephalic midline midway through mouse embryogenesis at E12.5. We examined the expression of Hs2st, Fgf2, and Erk1/2 activity in wild-type and Hs2st-/- mice. We found that Hs2st is expressed at high levels at the midline correlating with high levels of Erk1/2 activation and Erk1/2 activation was drastically reduced in the Hs2st-/- mutant at the rostral telencephalic midline. We also found that 2-O sulfation is specifically required for the binding of Fgf2 protein to Fgfr1, its major cell-surface receptor at the rostral telencephalic midline. We conclude that 2-O sulfated HS structures generated by Hs2st are needed to form productive signaling complexes between HS, Fgf2 and Fgfr1 that activate Erk1/2 at the midline. Overall, our data suggest the interesting possibility that differential expression of Hs2st targets the rostral telencephalic

  7. Multi-Compartmentalisation in the MAPK Signalling Pathway Contributes to the Emergence of Oscillatory Behaviour and to Ultrasensitivity

    PubMed Central

    Shuaib, Aban; Hartwell, Adam; Kiss-Toth, Endre; Holcombe, Mike

    2016-01-01

    Signal transduction through the Mitogen Activated Protein Kinase (MAPK) pathways is evolutionarily highly conserved. Many cells use these pathways to interpret changes to their environment and respond accordingly. The pathways are central to triggering diverse cellular responses such as survival, apoptosis, differentiation and proliferation. Though the interactions between the different MAPK pathways are complex, nevertheless, they maintain a high level of fidelity and specificity to the original signal. There are numerous theories explaining how fidelity and specificity arise within this complex context; spatio-temporal regulation of the pathways and feedback loops are thought to be very important. This paper presents an agent based computational model addressing multi-compartmentalisation and how this influences the dynamics of MAPK cascade activation. The model suggests that multi-compartmentalisation coupled with periodic MAPK kinase (MAPKK) activation may be critical factors for the emergence of oscillation and ultrasensitivity in the system. Finally, the model also establishes a link between the spatial arrangements of the cascade components and temporal activation mechanisms, and how both contribute to fidelity and specificity of MAPK mediated signalling. PMID:27243235

  8. Xiang-Qi-Tang and its active components exhibit anti-inflammatory and anticoagulant properties by inhibiting MAPK and NF-κB signaling pathways in LPS-treated rat cardiac microvascular endothelial cells.

    PubMed

    He, Chang-Liang; Yi, Peng-Fei; Fan, Qiao-Jia; Shen, Hai-Qing; Jiang, Xiao-Lin; Qin, Qian-Qian; Song, Zhou; Zhang, Cui; Wu, Shuai-Cheng; Wei, Xu-Bin; Li, Ying-Lun; Fu, Ben-Dong

    2013-04-01

    Xiang-Qi-Tang (XQT) is a Chinese herbal formula containing Cyperus rotundus, Astragalus membranaceus and Andrographis paniculata. Alpha-Cyperone (CYP), astragaloside IV (AS-IV) and andrographolide (AND) are the three major active components in this formula. XQT may modulate the inflammatory or coagulant responses. We therefore assessed the effects of XQT on lipopolysaccharide (LPS)-induced inflammatory model of rat cardiac microvascular endothelial cells (RCMECs). XQT, CYP, AS-IV and AND inhibited the production of tumor necrosis factor alpha (TNF-α), intercellular cell adhesion molecule-1 (ICAM-1) and plasminogen activator inhibitor-1 (PAI-1), and up-regulated the mRNA expression of Kruppel-like factor 2 (KLF2). XQT and CYP inhibited the secretion of tissue factor (TF). To further explore the mechanism, we found that XQT, or its active components CYP, AS-IV and AND significantly inhibited extracellular signal-regulated kinase (ERK), c-jun NH2-terminal kinase (JNK) and p38 phosphorylation protein expression as well as decreased the phosphorylation levels of nuclear factor κB (NF-κB) p65 proteins in LPS-stimulated RCMECs. These results suggested that XQT and its active components inhibited the expression of inflammatory and coagulant mediators via mitogen-activated protein kinase (MAPKs) and NF-κB signaling pathways. These findings may contribute to future research on the action mechanisms of this formula, as well as therapy for inflammation- or coagulation-related diseases.

  9. CX3CR1 Mediates Nicotine Withdrawal-Induced Hyperalgesia via Microglial P38 MAPK Signaling.

    PubMed

    Ding, Yonghong; Shi, Wenhui; Xie, Guannan; Yu, Ailan; Wang, Qinghe; Zhang, Zongwang

    2015-11-01

    Previously, we reported that nicotine withdrawal (NT) significantly increased pain sensitivity in rats. Recent reports suggest that fractalkine is involved in the spinal cord neuron-to-microglia activation via CX3CR1 signaling. However, its contribution to NT-induced hyperalgesia and the underlying mechanisms have yet to be elucidated. In the present study, a rat model of NT was used to test the changes in CX3CR1 expression in the spinal cord. We also evaluated the effect of the CX3CR1 neutralizing antibody on spinal microglial activity, the expression of phosphorylated p38-mitogen-activated protein kinase (p-p38-MAPK) and heat-induced pain responses. We established a NT model via subcutaneous injection of pure nicotine (3 mg/kg), three times daily for 7 days. The expression of CX3CR1 was studied by Western blot and immunofluorescence staining. Following NT, the rats received daily intrathecal injections of CX3CR1 neutralizing antibody for 3 days. The change in paw withdrawal latency (PWL) was observed. The activation of microglia and the expression of p-p38-MAPK were investigated by Western blot and immunofluorescence staining. The expression of CX3CR1 was significantly increased after NT and co-localized with IBA-1. NT rats treated with CX3CR1 neutralizing antibody showed significantly increased PWL on day 4 after NT. Furthermore, the activation of microglia and the expression of p-p38-MAPK in the spinal cord were suppressed. These results indicate that microglial CX3CR1/p38MAPK pathway is critical for the development of pain hypersensitivity after NT.

  10. Activin B Regulates Adipose-derived Mesenchymal Stem Cells to Promote Skin Wound Healing via Activation of the MAPK Signaling Pathway.

    PubMed

    Zhang, Lei; Xu, Pengcheng; Wang, Xueer; Zhang, Min; Yan, Yuan; Chen, Yinghua; Zhang, Lu; Zhang, Lin

    2017-04-07

    Adipose-derived stem cells (ADSCs) are multipotent stromal cells that can differentiate into a variety of cell types, including skin cells, and they can provide an abundant source of cells for skin tissue engineering and skin wound healing. The purpose of this study is to explore the therapeutic effects of activin B in combination with ADSCs and the possible signaling mechanism. In this study, we found that activin B was able to promote ADSC migration by inducing actin stress fiber formation in vitro. In vivo, activin B in combination with ADSCs was capable of enhancing α-SMA expression and wound closure. This combined treatment also promoted fibroblast and keratinocyte proliferation and accelerated re-epithelialization and collagen deposition. Moreover, activin B in combination with ADSCs boosted angiogenesis in the wound area. Further study of the mechanism revealed that activation of JNK and ERK signaling, but not p38 signaling, were required for activin B-induced ADSC actin stress fiber formation and cell migration. These results showed that activin B was able to activate JNK and ERK signaling pathways to induce actin stress fiber formation and ADSC migration to promote wound healing. These results suggest that combined treatment with activin B and ADSCs is a promising therapeutic strategy for the management of serious skin wounds.

  11. Mice with an N-Ethyl-N-Nitrosourea (ENU) Induced Tyr209Asn Mutation in Natriuretic Peptide Receptor 3 (NPR3) Provide a Model for Kyphosis Associated with Activation of the MAPK Signaling Pathway

    PubMed Central

    Nesbit, M. Andrew; Loh, Nellie Y.; Thomas, Gethin; Croucher, Peter I.; Brown, Matthew A.; Brown, Steve D. M.; Cox, Roger D.; Thakker, Rajesh V.

    2016-01-01

    Non-syndromic kyphosis is a common disorder that is associated with significant morbidity and has a strong genetic involvement; however, the causative genes remain to be identified, as such studies are hampered by genetic heterogeneity, small families and various modes of inheritance. To overcome these limitations, we investigated 12 week old progeny of mice treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU) using phenotypic assessments including dysmorphology, radiography, and dual-energy X-ray absorptiometry. This identified a mouse with autosomal recessive kyphosis (KYLB). KYLB mice, when compared to unaffected littermates, had: thoraco-lumbar kyphosis, larger vertebrae, and increased body length and increased bone area. In addition, female KYLB mice had increases in bone mineral content and plasma alkaline phosphatase activity. Recombination mapping localized the Kylb locus to a 5.5Mb region on chromosome 15A1, which contained 51 genes, including the natriuretic peptide receptor 3 (Npr3) gene. DNA sequence analysis of Npr3 identified a missense mutation, Tyr209Asn, which introduced an N-linked glycosylation consensus sequence. Expression of wild-type NPR3 and the KYLB-associated Tyr209Asn NPR3 mutant in COS-7 cells demonstrated the mutant to be associated with abnormal N-linked glycosylation and retention in the endoplasmic reticulum that resulted in its absence from the plasma membrane. NPR3 is a decoy receptor for C-type natriuretic peptide (CNP), which also binds to NPR2 and stimulates mitogen-activated protein kinase (MAPK) signaling, thereby increasing the number and size of hypertrophic chondrocytes. Histomorphometric analysis of KYLB vertebrae and tibiae showed delayed endochondral ossification and expansion of the hypertrophic zones of the growth plates, and immunohistochemistry revealed increased p38 MAPK phosphorylation throughout the growth plates of KYLB vertebrae. Thus, we established a model of kyphosis due to a novel NPR3 mutation, in

  12. Activation of multiple MAPK pathways (ERKs, JNKs, p38-MAPK) by diverse stimuli in the amphibian heart.

    PubMed

    Aggeli, I K; Gaitanaki, C; Lazou, A; Beis, I

    2001-05-01

    We investigated the expression and activation of three MAPK subfamilies in the isolated perfused amphibian heart. ERK was detected as a 43 kDa band; p38-MAPK was detected as a band corresponding to 38 kDa and JNKs were detected as two bands corresponding to 46 and 52 kDa, respectively. PMA induced the activation of the ERK pathway as assessed by determining the phosphorylation state of ERK and the upstream component MEK1/2. PD98059 abolished this activation. p38-MAPK was phosphorylated by sorbitol (almost 12-fold, maximal within 10-15 min) and JNKs were phosphorylated and activated by sorbitol or anoxia/reoxygenation (approximately 4- and 2.5-fold, respectively). SB203580 completely blocked the activation of p38-MAPK by sorbitol. These results indicate that the MAPK pathways activated by phorbol esters, hyperosmotic stress or anoxia/ reoxygenation in the amphibian heart may have an important role in this experimental system.

  13. Alternative Roles of STAT3 and MAPK Signaling Pathways in the MMPs Activation and Progression of Lung Injury Induced by Cigarette Smoke Exposure in ACE2 Knockout Mice

    PubMed Central

    Hung, Yi-Han; Hsieh, Wen-Yeh; Hsieh, Jih-Sheng; Liu, Fon-Chang; Tsai, Chin-Hung; Lu, Li-Che; Huang, Chen-Yi; Wu, Chien-Liang; Lin, Chih-Sheng

    2016-01-01

    Inflammation-mediated abnormalities in the renin-angiotensin system (RAS) and expression of matrix metalloproteinases (MMPs) are implicated in the pathogenesis of lung injury. Angiotensin converting enzyme II (ACE2), an angiotensin converting enzyme (ACE) homologue that displays antagonist effects on ACE/angiotensin II (Ang II) axis, could also play a protective role against lung diseases. However, the relationship between ACE2 and MMPs activation in lung injury is still largely unclear. The purpose of this study is to investigate whether MMPs activity could be affected by ACE2 and which ACE2 derived signaling pathways could be also involved via using a mouse model with lung injury induced by cigarette smoke (CS) exposure for 1 to 3 weeks. Wild-type (WT; C57BL/6) and ACE2 KO mice (ACE2-/-) were utilized to study CS-induced lung injury. Increases in the resting respiratory rate (RRR), pulmonary immunokines, leukocyte infiltration and bronchial hyperplasia were observed in the CS-exposed mice. Compared to WT mice, more serious physiopathological changes were found in ACE2-/- mice in the first week of CS exposure. CS exposure increased pulmonary ACE and ACE2 activities in WT mice, and significantly increased ACE in ACE2-/- mice. Furthermore, the activity of pulmonary MMPs was decreased in CS-exposed WT mice, whereas this activity was increased in ACE2-/- mice. CS exposure increased the pulmonary p-p38, p-JNK and p-ERK1/2 level in all mice. In ACE2-/- mice, a significant increase p-STAT3 signaling was detected; however, no effect was observed on the p-STAT3 level in WT mice. Our results support the hypothesis that ACE2 deficiency influences MMPs activation and STAT3 phosphorylation signaling to promote more pulmonary inflammation in the development of lung injury. PMID:27019629

  14. Induction of Macrophage Function in Human THP-1 Cells Is Associated with Rewiring of MAPK Signaling and Activation of MAP3K7 (TAK1) Protein Kinase

    PubMed Central

    Richter, Erik; Ventz, Katharina; Harms, Manuela; Mostertz, Jörg; Hochgräfe, Falko

    2016-01-01

    Macrophages represent the primary human host response to pathogen infection and link the immediate defense to the adaptive immune system. Mature tissue macrophages convert from circulating monocyte precursor cells by terminal differentiation in a process that is not fully understood. Here, we analyzed the protein kinases of the human monocytic cell line THP-1 before and after induction of macrophage differentiation by using kinomics and phosphoproteomics. When comparing the macrophage-like state with the monocytic precursor, 50% of the kinome was altered in expression and even 71% of covered kinase phosphorylation sites were affected. Kinome rearrangements are for example characterized by a shift of overrepresented cyclin-dependent kinases associated with cell cycle control in monocytes to calmodulin-dependent kinases and kinases involved in proinflammatory signaling. Eventually, we show that monocyte-to-macrophage differentiation is associated with major rewiring of mitogen-activated protein kinase signaling networks and demonstrate that protein kinase MAP3K7 (TAK1) acts as the key signaling hub in bacterial killing, chemokine production and differentiation. Our study proves the fundamental role of protein kinases and cellular signaling as major drivers of macrophage differentiation and function. The finding that MAP3K7 is central to macrophage function suggests MAP3K7 and its networking partners as promising targets in host-directed therapy for macrophage-associated disease. PMID:27066479

  15. TAB3 involves in hepatic insulin resistance through activation of MAPK pathway.

    PubMed

    Zhao, Yun; Tang, Zhuqi; Zhu, Xiaohui; Wang, Xueqin; Wang, Cuifang; Zhang, Wanlu; Xia, Nana; Wang, Suxin; Huang, Jieru; Cui, Shiwei

    2015-12-01

    Insulin resistance is often accompanied by chronic inflammatory responses. The mitogen-activated protein kinase (MAPK) pathway is rapidly activated in response to many inflammatory cytokines. But the functional role of MAPKs in palmitate-induced insulin resistance has yet to be clarified. In this study, we found that transforming growth factor β-activated kinase binding protein-3 (TAB3) was up-regulated in insulin resistance. Considering the relationship between transforming growth factor β-activated kinase (TAK1) and MAPK pathway, we assumed TAB3 involved in insulin resistance through activation of MAPK pathway. To certify this hypothesis, we knocked down TAB3 in palmitate treated HepG2 cells and detected subsequent biological responses. Importantly, TAB3 siRNA directly reversed insulin sensitivity by improving insulin signal transduction. Moreover, silencing of TAB3 could facilitate hepatic glucose uptake, reverse gluconeogenesis and improve ectopic fat accumulation. Meanwhile, we found that the positive effect of knocking down TAB3 was more significant when insulin resistance occurred. All these results indicate that TAB3 acts as a negative regulator in insulin resistance through activation of MAPK pathway.

  16. Single-Cell Analysis Reveals that Insulation Maintains Signaling Specificity between Two Yeast MAPK Pathways with Common Components

    PubMed Central

    Patterson, Jesse C.; Klimenko, Evguenia S.; Thorner, Jeremy

    2014-01-01

    Eukaryotic cells use multiple mitogen-activated protein kinase (MAPK) cascades to evoke appropriate responses to external stimuli. In Saccharomyces cerevisiae, the MAPK Fus3 is activated by pheromone-binding G protein-coupled receptors to promote mating, whereas the MAPK Hog1 is activated by hyperosmotic stress to elicit the high osmolarity glycerol (HOG) response. Although these MAPK pathways share several upstream components, exposure to either pheromone or osmolyte alone triggers only the appropriate response. We used fluorescent localization- and transcription-specific reporters to assess activation of these pathways in individual cells on the minute and hour timescale, respectively. Dual activation of these two MAPK pathways occurred over a broad range of stimulant concentrations and temporal regimes in wild-type cells subjected to co-stimulation. Thus, signaling specificity is achieved through an “insulation” mechanism, not a “cross-inhibition” mechanism. Furthermore, we showed that there was a critical period during which Hog1 activity had to occur for proper insulation of the HOG pathway. PMID:20959523

  17. Socs36E Controls Niche Competition by Repressing MAPK Signaling in the Drosophila Testis

    PubMed Central

    Amoyel, Marc; Anderson, Jason; Suisse, Annabelle; Glasner, Johanna; Bach, Erika A.

    2016-01-01

    The Drosophila testis is a well-established system for studying stem cell self-renewal and competition. In this tissue, the niche supports two stem cell populations, germ line stem cells (GSCs), which give rise to sperm, and somatic stem cells called cyst stem cells (CySCs), which support GSCs and their descendants. It has been established that CySCs compete with each other and with GSCs for niche access, and mutations have been identified that confer increased competitiveness to CySCs, resulting in the mutant stem cell and its descendants outcompeting wild type resident stem cells. Socs36E, which encodes a negative feedback inhibitor of the JAK/STAT pathway, was the first identified regulator of niche competition. The competitive behavior of Socs36E mutant CySCs was attributed to increased JAK/STAT signaling. Here we show that competitive behavior of Socs36E mutant CySCs is due in large part to unbridled Mitogen-Activated Protein Kinase (MAPK) signaling. In Socs36E mutant clones, MAPK activity is elevated. Furthermore, we find that clonal upregulation of MAPK in CySCs leads to their outcompetition of wild type CySCs and of GSCs, recapitulating the Socs36E mutant phenotype. Indeed, when MAPK activity is removed from Socs36E mutant clones, they lose their competitiveness but maintain self-renewal, presumably due to increased JAK/STAT signaling in these cells. Consistently, loss of JAK/STAT activity in Socs36E mutant clones severely impairs their self-renewal. Thus, our results enable the genetic separation of two essential processes that occur in stem cells. While some niche signals specify the intrinsic property of self-renewal, which is absolutely required in all stem cells for niche residence, additional signals control the ability of stem cells to compete with their neighbors. Socs36E is node through which these processes are linked, demonstrating that negative feedback inhibition integrates multiple aspects of stem cell behavior. PMID:26807580

  18. An evolutionarily conserved Rit GTPase–p38 MAPK signaling pathway mediates oxidative stress resistance

    PubMed Central

    Cai, Weikang; Rudolph, Jennifer L.; Harrison, Susan M. W.; Jin, Ling; Frantz, Aubrey L.; Harrison, Douglas A.; Andres, Douglas A.

    2011-01-01

    Ras-related small GTP-binding proteins control a wide range of cellular processes by regulating a variety of effector pathways, including prominent roles in the control of mitogen-activated protein kinase (MAPK) cascades. Although the regulatory role(s) for many Ras family GTPases are well established, the physiological function for the Rit/Rin subfamily has been lacking. Here, using both knockout mice and Drosophila models, we demonstrate an evolutionarily conserved role for Rit subfamily GTPases (mammalian Rit and Rin, and the Drosophila RIC homologue) in governing survival in response to oxidative stress. Primary embryonic fibroblasts derived from Rit knockout mice display increased apoptosis and selective disruption of MAPK signaling following reactive oxygen species (ROS) exposure but not in response to endoplasmic reticulum stress or DNA damage. These deficits include a reduction in ROS-mediated stimulation of a p38-MK2-HSP27 signaling cascade that controls Akt activation, directing Bad phosphorylation to promote cell survival. Furthermore, D-RIC null flies display increased susceptibility to environmental stresses and reduced stress-dependent p38 signaling, extending the Rit-p38 survival pathway to Drosophila. Together, our studies establish the Rit GTPases as critical regulators of an evolutionarily conserved, p38 MAPK–dependent signaling cascade that functions as an important survival mechanism for cells in response to oxidative stress. PMID:21737674

  19. Characterization of early events involved in human dendritic cell maturation induced by sensitizers: Cross talk between MAPK signalling pathways

    SciTech Connect

    Trompezinski, Sandra; Migdal, Camille; Tailhardat, Magalie; Le Varlet, Beatrice; Courtellemont, Pascal; Haftek, Marek; Serres, Mireille

    2008-08-01

    Dendritic cells (DCs), efficient-antigen presenting cells play an important role in initiating and regulating immune responses. DC maturation following exposure to nickel or DNCB induced an up-regulation of phenotypic markers and inflammatory cytokine secretion. Early intracellular mechanisms involved in DC maturation required to be precise. To address this purpose, DCs derived from human monocytes were treated with sensitizers (nickel, DNCB or thimerosal) in comparison with an irritant (SDS). Our data confirming the up-regulation of CD86, CD54 and cytokine secretion (IL-8 and TNF{alpha}) induced by sensitizers but not by SDS, signalling transduction involved in DC maturation was investigated using these chemicals. Kinase activity measurement was assessed using two new sensitive procedures (Face{sup TM} and CBA) requiring few cells. SDS did not induce changes in signalling pathways whereas NiSO{sub 4}, DNCB and thimerosal markedly activated p38 MAPK and JNK, in contrast Erk1/2 phosphorylation was completely inhibited by DNCB or thimerosal and only activated by nickel. A pre-treatment with p38 MAPK inhibitor (SB203580) suppressed Erk1/2 inhibition induced by DNCB or thimerosal demonstrating a direct interaction between p38 MAPK and Erk1/2. A pre-treatment with an antioxidant, N-acetyl-L-cysteine (NAC) markedly reduced Erk1/2 inhibition and p38 MAPK phosphorylation induced by DNCB and thimerosal, suggesting a direct activation of p38 MAPK via an oxidative stress and a regulation of MAPK signalling pathways depending on chemicals. Because of a high sensitivity of kinase activity measurements, these procedures will be suitable for weak or moderate sensitizer screening.

  20. Signaling intermediates (MAPK and PI3K) as therapeutic targets in NSCLC.

    PubMed

    Ciuffreda, Ludovica; Incani, Ursula Cesta; Steelman, Linda S; Abrams, Stephen L; Falcone, Italia; Curatolo, Anais Del; Chappell, William H; Franklin, Richard A; Vari, Sabrina; Cognetti, Francesco; McCubrey, James A; Milella, Michele

    2014-01-01

    The RAS/RAF/MEK/ ERK and the PI3K/AKT/mTOR pathways govern fundamental physiological processes, such as cell proliferation, differentiation, metabolism, cytoskeleton reorganization and cell death and survival. Constitutive activation of these signal transduction pathways is a required hallmark of cancer and dysregulation, on either genetic or epigenetic grounds, of these pathways has been implicated in the initiation, progression and metastastic spread of lung cances. Targeting components of the MAPK and PI3K cascades is thus an attractive strategy in the development of novel therapeutic approaches to treat lung cancer, although the use of single pathway inhibitors has met with limited clinical success so far. Indeed, the presence of intra- and inter-pathway compensatory loops that re-activate the very same cascade, either upstream or downstream the point of pharmacological blockade, or activate the alternate pathway following the blockade of one signaling cascade has been demonstrated, potentially driving preclinical (and possibly clinical) resistance. Therefore, the blockade of both pathways with combinations of signaling inhibitors might result in a more efficient anti-tumor effect, and thus potentially overcome and/or delay clinical resistance, as compared with single agent. The current review aims at summarizing the current status of preclinical and clinical research with regard to pathway crosstalks between the MAPK and PI3K cascades in NSCLC and the rationale for combined therapeutic pathway targeting.

  1. MAPK signaling downstream to TLR4 contributes to paclitaxel-induced peripheral neuropathy

    PubMed Central

    Li, Yan; Zhang, Hongmei; Kosturakis, Alyssa K.; Cassidy, Ryan M.; Zhang, Haijun; Kennamer-Chapman, Ross M.; Jawad, Abdul Basit; Colomand, Cecilia M.; Harrison, Daniel S.; Dougherty, Patrick M.

    2015-01-01

    Toll-like receptor 4 (TLR4) has been implicated as a locus for initiation of paclitaxel related chemotherapy induced peripheral neuropathy (CIPN). This project explores the involvement of the immediate down-stream signal molecules in inducing paclitaxel CIPN. Mitogen-activated protein kinases (MAPK) and nuclear factor-κB (NFκB) were measured in dorsal root ganglia (DRG) and the spinal cord over time using Western blot and immunohistochemistry in a rat model of paclitaxel CIPN. The effects of MAPK inhibitors in preventing and reversing behavioral signs of CIPN were also measured (group sizes 4–9). Extracellular signal related kinase (ERK1/2) and p38 but not c-Jun N terminal kinase (JNK) or PI3K-Akt signaling expression was increased in DRG. Phospho-ERK1/2 staining was co-localized to small CGRP-positive DRG neurons in cell profiles surrounding large DRG neurons consistent with satellite glial cells. The expression of phospho-P38 was co-localized to small IB4-positive and CGRP-positive DRG neurons. The TLR4 antagonist LPS derived from R. sphaeroides (LPS-RS) inhibited paclitaxel-induced phosphorylation of ERK1/2 and P38. The MAPK inhibitors PD98059 (MEK1/2), U0126 (MEK1/2) and SB203580 (P38) prevented but did not reverse paclitaxel-induced behavioral hypersensitivity. Paclitaxel treatment resulted in phosphorylation of Inhibitor α of NFκB (IκBα) in DRG resulting in an apparent release of NFκB from the IκBα-NFκB complex as increased expression of nuclear NFκB was also observed. LPS-RS inhibited paclitaxel-induced translocation of NFκB in DRG. No change was observed in spinal NFκB. These results implicate TLR4 signaling via MAP kinases and NFκB in the induction and maintenance of paclitaxel-related CIPN. PMID:26065826

  2. Atorvastatin Prevents Glutamate Uptake Reduction Induced by Quinolinic Acid Via MAPKs Signaling.

    PubMed

    Vandresen-Filho, S; Martins, W C; Bertoldo, D B; Rieger, D K; Maestri, M; Leal, R B; Tasca, C I

    2016-08-01

    Statins have been shown to promote neuroprotection in a wide range of neurological disorders. However, the mechanisms involved in such effects of statins are not fully understood. Quinolinic acid (QA) is a neurotoxin that induces seizures when infused in vivo and promotes glutamatergic excitotoxicity in the central nervous system. The aim of this study was to evaluate the putative glutamatergic mechanisms and the intracellular signaling pathways involved in the atorvastatin neuroprotective effects against QA toxicity. Atorvastatin (10 mg/kg) treatment for 7 days prevented the QA-induced decrease in glutamate uptake, but had no effect on increased glutamate release induced by QA. Moreover, atorvastatin treatment increased the phosphorylation of ERK1 and prevented the decrease in Akt phosphorylation induced by QA. Neither atorvastatin treatment nor QA infusion altered glutamine synthetase activity or the levels of phosphorylation of p38(MAPK) or JNK1/2 during the evaluation. Inhibition of MEK/ERK signaling pathway, but not PI3K/Akt signaling, abolished the neuroprotective effect of atorvastatin against QA-induced decrease in glutamate uptake. Our data suggest that atorvastatin protective effects against QA toxicity are related to modulation of glutamate transporters via MAPK/ERK signaling pathway.

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

    PubMed

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

    2016-01-01

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

  4. Kaempferol Attenuates Cardiac Hypertrophy via Regulation of ASK1/MAPK Signaling Pathway and Oxidative Stress.

    PubMed

    Feng, Hong; Cao, Jianlei; Zhang, Guangyu; Wang, Yanggan

    2017-02-20

    Kaempferol has been demonstrated to provide benefits for the treatment of atherosclerosis, coronary heart disease, hyperlipidemia, and diabetes through its antioxidant and anti-inflammatory properties. However, its role in cardiac hypertrophy remains to be elucidated. The aim of our study was to investigate the effects of kaempferol on cardiac hypertrophy and the underlying mechanism. Mice subjected to aorta banding were treated with or without kaempferol (100 mg/kg/d, p. o.) for 6 weeks. Echocardiography was performed to evaluate cardiac function. Mice hearts were collected for pathological observation and molecular mechanism investigation. H9c2 cardiomyocytes were stimulated with or without phenylephrine for in vitro study. Kaempferol significantly attenuated cardiac hypertrophy induced by aorta banding as evidenced by decreased cardiomyocyte areas and interstitial fibrosis, accompanied with improved cardiac functions and decreased apoptosis. The ASK1/MAPK signaling pathways (JNK1/2 and p38) were markedly activated in the aorta banding mouse heart but inhibited by kaempferol treatment. In in vitro experiments, kaempferol also inhibited the activity of ASK1/JNK1/2/p38 signaling pathway and the enlargement of H9c2 cardiomyocytes. Furthermore, our study revealed that kaempferol could protect the mouse heart and H9c2 cells from pathological oxidative stress. Our investigation indicated that treatment with kaempferol protects against cardiac hypertrophy, and its cardioprotection may be partially explained by the inhibition of the ASK1/MAPK signaling pathway and the regulation of oxidative stress.

  5. RAS-MAPK pathway epigenetic activation in cancer: miRNAs in action

    PubMed Central

    Masliah-Planchon, Julien; Garinet, Simon; Pasmant, Eric

    2016-01-01

    The highly conserved RAS-mitogen activated protein kinase (MAPK) signaling pathway is involved in a wide range of cellular processes including differentiation, proliferation, and survival. Somatic mutations in genes encoding RAS-MAPK components frequently occur in many tumors, making the RAS-MAPK a critical pathway in human cancer. Since the pioneering study reporting that let-7 miRNA acted as tumor suppressor by repressing the RAS oncogene, growing evidence has suggested the importance of miRNAs targeting the RAS-MAPK in oncogenesis. MiRNAs alterations in human cancers may act as a rheostat of the oncogenic RAS signal that is often amplified as cancers progress. However, specific mechanisms leading to miRNAs deregulation and their functional consequences in cancer are far from being fully elucidated. In this review, we provide an experimental-validated map of RAS-MAPK oncomiRs and tumor suppressor miRNAs from transmembrane receptor to downstream ERK proteins. MiRNAs could be further considered as potential genetic biomarkers for diagnosis, prognosis, or therapeutic purpose. PMID:26646588

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

    SciTech Connect

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

    2006-08-18

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

  7. Involvement of the p38 MAPK signaling pathway in S-phase cell-cycle arrest induced by Furazolidone in human hepatoma G2 cells.

    PubMed

    Sun, Yu; Tang, Shusheng; Jin, Xi; Zhang, Chaoming; Zhao, Wenxia; Xiao, Xilong

    2013-12-01

    Given the previously described essential role for the p38 mitogen-activation protein kinase (p38 MAPK) signaling pathway in human hepatoma G2 cells (HepG2), we undertook the present study to investigate the role of the p38 MAPK signaling pathway in cell-cycle arrest induced by Furazolidone (FZD). The aim of this study was to determine the effects of FZD on HepG2 cells by activating and inhibiting the p38 MAPK signaling pathway. The cell cycle and proliferation of HepG2 cells treated with FZD were detected by flow cytometry and MTT assay in the presence or absence of p38 MAPK inhibitors (SB203580), respectively. Cyclin D1, cyclin D3 and CDK6 were detected by quantitative real-time PCR and western blot analysis. Our data showed that p38 MAPK became phosphorylated after stimulation with FZD. Activation of p38 MAPK could arise S-phase cell-cycle arrest and suppress cell proliferation. Simultaneously, inhibition of the p38 MAPK signaling pathway significantly prevented S-phase cell-cycle arrest, increased the percentage of cell viability and decreased the expression of cyclin D1, cyclin D3 and CDK6. These results demonstrated that FZD arose S-phase cell-cycle arrest via activating the p38 MAPK signaling pathway in HepG2 cells. Cyclin D1, cyclin D3 and CDK6 are target genes functioning at the downstream of p38 MAPK in HepG2 cells induced by FZD.

  8. Estrogen receptor beta growth-inhibitory effects are repressed through activation of MAPK and PI3K signalling in mammary epithelial and breast cancer cells.

    PubMed

    Cotrim, C Z; Fabris, V; Doria, M L; Lindberg, K; Gustafsson, J-Å; Amado, F; Lanari, C; Helguero, L A

    2013-05-09

    Two thirds of breast cancers express estrogen receptors (ER). ER alpha (ERα) mediates breast cancer cell proliferation, and expression of ERα is the standard choice to indicate adjuvant endocrine therapy. ERbeta (ERβ) inhibits growth in vitro; its effects in vivo have been incompletely investigated and its role in breast cancer and potential as alternative target in endocrine therapy needs further study. In this work, mammary epithelial (EpH4 and HC11) and breast cancer (MC4-L2) cells with endogenous ERα and ERβ expression and T47-D human breast cancer cells with recombinant ERβ (T47-DERβ) were used to explore effects exerted in vitro and in vivo by the ERβ agonists 2,3-bis (4-hydroxy-phenyl)-propionitrile (DPN) and 7-bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol (WAY). In vivo, ERβ agonists induced mammary gland hyperplasia and MC4-L2 tumour growth to a similar extent as the ERα agonist 4,4',4''-(4-propyl-(1H)-pyrazole-1,3,5-triyl) trisphenol (PPT) or 17β-estradiol (E2) and correlated with higher number of mitotic and lower number of apoptotic features. In vitro, in MC4-L2, EpH4 or HC11 cells incubated under basal conditions, ERβ agonists induced apoptosis measured as upregulation of p53 and apoptosis-inducible factor protein levels and increased caspase 3 activity, whereas PPT and E2 stimulated proliferation. However, when extracellular signal-regulated kinase 1 and 2 (ERK ½) were activated by co-incubation with basement membrane extract or epidermal growth factor, induction of apoptosis by ERβ agonists was repressed and DPN induced proliferation in a similar way as E2 or PPT. In a context of active ERK ½, phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/RAC-alpha serine/threonine-protein kinase (AKT) signalling was necessary to allow proliferation stimulated by ER agonists. Inhibition of MEK ½ with UO126 completely restored ERβ growth-inhibitory effects, whereas inhibition of PI3K by LY294002 inhibited ERβ-induced proliferation. These

  9. Metabolic oxidative stress elicited by the copper(II) complex [Cu(isaepy)2] triggers apoptosis in SH-SY5Y cells through the induction of the AMP-activated protein kinase/p38MAPK/p53 signalling axis: evidence for a combined use with 3-bromopyruvate in neuroblastoma treatment.

    PubMed

    Filomeni, Giuseppe; Cardaci, Simone; Da Costa Ferreira, Ana Maria; Rotilio, Giuseppe; Ciriolo, Maria Rosa

    2011-08-01

    We have demonstrated previously that the complex bis[(2-oxindol-3-ylimino)-2-(2-aminoethyl)pyridine-N,N']copper(II), named [Cu(isaepy)(2)], induces AMPK (AMP-activated protein kinase)-dependent/p53-mediated apoptosis in tumour cells by targeting mitochondria. In the present study, we found that p38(MAPK) (p38 mitogen-activated protein kinase) is the molecular link in the phosphorylation cascade connecting AMPK to p53. Transfection of SH-SY5Y cells with a dominant-negative mutant of AMPK resulted in a decrease in apoptosis and a significant reduction in phospho-active p38(MAPK) and p53. Similarly, reverse genetics of p38(MAPK) yielded a reduction in p53 and a decrease in the extent of apoptosis, confirming an exclusive hierarchy of activation that proceeds via AMPK/p38(MAPK)/p53. Fuel supplies counteracted [Cu(isaepy)(2)]-induced apoptosis and AMPK/p38(MAPK)/p53 activation, with glucose being the most effective, suggesting a role for energetic imbalance in [Cu(isaepy)(2)] toxicity. Co-administration of 3BrPA (3-bromopyruvate), a well-known inhibitor of glycolysis, and succinate dehydrogenase, enhanced apoptosis and AMPK/p38(MAPK)/p53 signalling pathway activation. Under these conditions, no toxic effect was observed in SOD (superoxide dismutase)-overexpressing SH-SY5Y cells or in PCNs (primary cortical neurons), which are, conversely, sensitized to the combined treatment with [Cu(isaepy)(2)] and 3BrPA only if grown in low-glucose medium or incubated with the glucose-6-phosphate dehydrogenase inhibitor dehydroepiandrosterone. Overall, the results suggest that NADPH deriving from the pentose phosphate pathway contributes to PCN resistance to [Cu(isaepy)(2)] toxicity and propose its employment in combination with 3BrPA as possible tool for cancer treatment.

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

    PubMed

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

    1999-11-19

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

  11. Layer specific and general requirements for ERK/MAPK signaling in the developing neocortex

    PubMed Central

    Xing, Lei; Larsen, Rylan S; Bjorklund, George Reed; Li, Xiaoyan; Wu, Yaohong; Philpot, Benjamin D; Snider, William D; Newbern, Jason M

    2016-01-01

    Aberrant signaling through the Raf/MEK/ERK (ERK/MAPK) pathway causes pathology in a family of neurodevelopmental disorders known as 'RASopathies' and is implicated in autism pathogenesis. Here, we have determined the functions of ERK/MAPK signaling in developing neocortical excitatory neurons. Our data reveal a critical requirement for ERK/MAPK signaling in the morphological development and survival of large Ctip2+ neurons in layer 5. Loss of Map2k1/2 (Mek1/2) led to deficits in corticospinal tract formation and subsequent corticospinal neuron apoptosis. ERK/MAPK hyperactivation also led to reduced corticospinal axon elongation, but was associated with enhanced arborization. ERK/MAPK signaling was dispensable for axonal outgrowth of layer 2/3 callosal neurons. However, Map2k1/2 deletion led to reduced expression of Arc and enhanced intrinsic excitability in both layers 2/3 and 5, in addition to imbalanced synaptic excitation and inhibition. These data demonstrate selective requirements for ERK/MAPK signaling in layer 5 circuit development and general effects on cortical pyramidal neuron excitability. DOI: http://dx.doi.org/10.7554/eLife.11123.001 PMID:26848828

  12. Stepwise metamorphosis of the tubeworm Hydroides elegans is mediated by a bacterial inducer and MAPK signaling.

    PubMed

    Shikuma, Nicholas J; Antoshechkin, Igor; Medeiros, João M; Pilhofer, Martin; Newman, Dianne K

    2016-09-06

    Diverse animal taxa metamorphose between larval and juvenile phases in response to bacteria. Although bacteria-induced metamorphosis is widespread among metazoans, little is known about the molecular changes that occur in the animal upon stimulation by bacteria. Larvae of the tubeworm Hydroides elegans metamorphose in response to surface-bound Pseudoalteromonas luteoviolacea bacteria, producing ordered arrays of phage tail-like metamorphosis-associated contractile structures (MACs). Sequencing the Hydroides genome and transcripts during five developmental stages revealed that MACs induce the regulation of groups of genes important for tissue remodeling, innate immunity, and mitogen-activated protein kinase (MAPK) signaling. Using two MAC mutations that block P. luteoviolacea from inducing settlement or metamorphosis and three MAPK inhibitors, we established a sequence of bacteria-induced metamorphic events: MACs induce larval settlement; then, particular properties of MACs encoded by a specific locus in P. luteoviolacea initiate cilia loss and activate metamorphosis-associated transcription; finally, signaling through p38 and c-Jun N-terminal kinase (JNK) MAPK pathways alters gene expression and leads to morphological changes upon initiation of metamorphosis. Our results reveal that the intricate interaction between Hydroides and P. luteoviolacea can be dissected using genomic, genetic, and pharmacological tools. Hydroides' dependency on bacteria for metamorphosis highlights the importance of external stimuli to orchestrate animal development. The conservation of Hydroides genome content with distantly related deuterostomes (urchins, sea squirts, and humans) suggests that mechanisms of bacteria-induced metamorphosis in Hydroides may have conserved features in diverse animals. As a major biofouling agent, insight into the triggers of Hydroides metamorphosis might lead to practical strategies for fouling control.

  13. Stepwise metamorphosis of the tubeworm Hydroides elegans is mediated by a bacterial inducer and MAPK signaling

    PubMed Central

    Shikuma, Nicholas J.; Antoshechkin, Igor; Medeiros, João M.; Pilhofer, Martin; Newman, Dianne K.

    2016-01-01

    Diverse animal taxa metamorphose between larval and juvenile phases in response to bacteria. Although bacteria-induced metamorphosis is widespread among metazoans, little is known about the molecular changes that occur in the animal upon stimulation by bacteria. Larvae of the tubeworm Hydroides elegans metamorphose in response to surface-bound Pseudoalteromonas luteoviolacea bacteria, producing ordered arrays of phage tail-like metamorphosis-associated contractile structures (MACs). Sequencing the Hydroides genome and transcripts during five developmental stages revealed that MACs induce the regulation of groups of genes important for tissue remodeling, innate immunity, and mitogen-activated protein kinase (MAPK) signaling. Using two MAC mutations that block P. luteoviolacea from inducing settlement or metamorphosis and three MAPK inhibitors, we established a sequence of bacteria-induced metamorphic events: MACs induce larval settlement; then, particular properties of MACs encoded by a specific locus in P. luteoviolacea initiate cilia loss and activate metamorphosis-associated transcription; finally, signaling through p38 and c-Jun N-terminal kinase (JNK) MAPK pathways alters gene expression and leads to morphological changes upon initiation of metamorphosis. Our results reveal that the intricate interaction between Hydroides and P. luteoviolacea can be dissected using genomic, genetic, and pharmacological tools. Hydroides' dependency on bacteria for metamorphosis highlights the importance of external stimuli to orchestrate animal development. The conservation of Hydroides genome content with distantly related deuterostomes (urchins, sea squirts, and humans) suggests that mechanisms of bacteria-induced metamorphosis in Hydroides may have conserved features in diverse animals. As a major biofouling agent, insight into the triggers of Hydroides metamorphosis might lead to practical strategies for fouling control. PMID:27551098

  14. Dipeptide species regulate p38MAPK-Smad3 signalling to maintain chronic myelogenous leukaemia stem cells.

    PubMed

    Naka, Kazuhito; Jomen, Yoshie; Ishihara, Kaori; Kim, Junil; Ishimoto, Takahiro; Bae, Eun-Jin; Mohney, Robert P; Stirdivant, Steven M; Oshima, Hiroko; Oshima, Masanobu; Kim, Dong-Wook; Nakauchi, Hiromitsu; Takihara, Yoshihiro; Kato, Yukio; Ooshima, Akira; Kim, Seong-Jin

    2015-08-20

    Understanding the specific survival of the rare chronic myelogenous leukaemia (CML) stem cell population could provide a target for therapeutics aimed at eradicating these cells. However, little is known about how survival signalling is regulated in CML stem cells. In this study, we survey global metabolic differences between murine normal haematopoietic stem cells (HSCs) and CML stem cells using metabolomics techniques. Strikingly, we show that CML stem cells accumulate significantly higher levels of certain dipeptide species than normal HSCs. Once internalized, these dipeptide species activate amino-acid signalling via a pathway involving p38MAPK and the stemness transcription factor Smad3, which promotes CML stem cell maintenance. Importantly, pharmacological inhibition of dipeptide uptake inhibits CML stem cell activity in vivo. Our results demonstrate that dipeptide species support CML stem cell maintenance by activating p38MAPK-Smad3 signalling in vivo, and thus point towards a potential therapeutic target for CML treatment.

  15. The p38 mitogen-activated protein kinase (MAPK) pathway in rheumatoid arthritis

    PubMed Central

    Schett, G; Zwerina, J; Firestein, G

    2009-01-01

    Chronic inflammatory processes are based on a sustained and tightly regulated communication network among different cells types. This network comprises extracellular mediators such as cytokines, chemokines and matrix-degrading proteases, which orchestrate the participation of cells in the chronic inflammatory process. The mirrors of this outside communication world are intracellular transcription factor pathways, which shuttle information about inflammatory stimuli to the cell nucleus. This review examines the function of one key signal transduction pathway of inflammation—the p38 mitogen-activated protein kinases (p38MAPK). The signalling pathway is considered as crucial for the induction and maintenance of chronic inflammation, and its components thus emerge as interesting molecular targets of small molecule inhibitors for controlling inflammation. This review not only summarises the current knowledge of activation, regulation and function of the p38MAPK pathway but also examines the role of this pathway in clinical disease. It gives an overview of current evidence of p38MAPK activation in inflammatory arthritis and elaborates the key molecular determinants which contribute to p38MAPK activation in joint disease. PMID:17827184

  16. Cytometry-based single-cell analysis of intact epithelial signaling reveals MAPK activation divergent from TNF-α-induced apoptosis in vivo

    PubMed Central

    Simmons, Alan J; Banerjee, Amrita; McKinley, Eliot T; Scurrah, Cherie' R; Herring, Charles A; Gewin, Leslie S; Masuzaki, Ryota; Karp, Seth J; Franklin, Jeffrey L; Gerdes, Michael J; Irish, Jonathan M; Coffey, Robert J; Lau, Ken S

    2015-01-01

    Understanding heterogeneous cellular behaviors in a complex tissue requires the evaluation of signaling networks at single-cell resolution. However, probing signaling in epithelial tissues using cytometry-based single-cell analysis has been confounded by the necessity of single-cell dissociation, where disrupting cell-to-cell connections inherently perturbs native cell signaling states. Here, we demonstrate a novel strategy (Disaggregation for Intracellular Signaling in Single Epithelial Cells from Tissue—DISSECT) that preserves native signaling for Cytometry Time-of-Flight (CyTOF) and fluorescent flow cytometry applications. A 21-plex CyTOF analysis encompassing core signaling and cell-identity markers was performed on the small intestinal epithelium after systemic tumor necrosis factor-alpha (TNF-α) stimulation. Unsupervised and supervised analyses robustly selected signaling features that identify a unique subset of epithelial cells that are sensitized to TNF-α-induced apoptosis in the seemingly homogeneous enterocyte population. Specifically, p-ERK and apoptosis are divergently regulated in neighboring enterocytes within the epithelium, suggesting a mechanism of contact-dependent survival. Our novel single-cell approach can broadly be applied, using both CyTOF and multi-parameter flow cytometry, for investigating normal and diseased cell states in a wide range of epithelial tissues. PMID:26519361

  17. RhoA and MAPK signal transduction pathways regulate NHE1-dependent proximal tubule cell apoptosis after mechanical stretch.

    PubMed

    Bocanegra, Victoria; Gil Lorenzo, Andrea Fernanda; Cacciamani, Valeria; Benardón, María Eugenia; Costantino, Valeria Victoria; Vallés, Patricia G

    2014-10-01

    Mechanical deformation after congenital ureteral obstruction is traduced into biochemical signals leading to tubular atrophy due to epithelial cell apoptosis. We investigated whether Na(+)/H(+) exchanger 1 (NHE1) could be responsible for HK-2 cell apoptosis induction in response to mechanical stretch through its ability to function as a control point of RhoA and MAPK signaling pathways. When mechanical stretch was applied to HK-2 cells, cell apoptosis was associated with diminished NHE1 expression and RhoA activation. The RhoA signaling pathway was confirmed to be upstream from the MAPK cascade when HK-2 cells were transfected with the active RhoA-V14 mutant, showing higher ERK1/2 expression and decreased p38 activation associated with NHE1 downregulation. NHE1 participation in apoptosis induction was confirmed by specific small interfering RNA NHE1 showing caspase-3 activation and decreased Bcl-2 expression. The decreased NHE1 expression was correlated with abnormal NHE1 activity addressed by intracellular pH measurements. These results demonstrate that mitochondrial proximal tubule cell apoptosis in response to mechanical stretch is orchestrated by signaling pathways initiated by the small GTPase RhoA and followed by the opposing effects of ERK1/2 and p38 MAPK phosphorylation, regulating NHE1 decreased expression and activity.

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  20. 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

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

    PubMed Central

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

    2015-01-01

    . Understanding how KOR activation produces dysphoria is key to the development of better analgesics and to defining how the endogenous dynorphin opioids produce their depression-like effects. Results in this study show that the aversive effects of κ receptor activation required arrestin-dependent p38α MAPK activation in dopamine neurons but did not require inhibition of dopamine release in the nucleus accumbens. Thus, contrary to the prevailing view, inhibition of mesolimbic dopamine release does not mediate the aversive effects of KOR activation and functionally selective κ opioids that do not activate arrestin signaling may be effective analgesics lacking dysphoric effects. PMID:26377476

  2. FGF/MAPK signaling sets the switching threshold of a bistable circuit controlling cell fate decisions in embryonic stem cells

    PubMed Central

    Schröter, Christian; Rué, Pau; Mackenzie, Jonathan Peter; Martinez Arias, Alfonso

    2015-01-01

    Intracellular transcriptional regulators and extracellular signaling pathways together regulate the allocation of cell fates during development, but how their molecular activities are integrated to establish the correct proportions of cells with particular fates is not known. Here we study this question in the context of the decision between the epiblast (Epi) and the primitive endoderm (PrE) fate that occurs in the mammalian preimplantation embryo. Using an embryonic stem cell (ESC) model, we discover two successive functions of FGF/MAPK signaling in this decision. First, the pathway needs to be inhibited to make the PrE-like gene expression program accessible for activation by GATA transcription factors in ESCs. In a second step, MAPK signaling levels determine the threshold concentration of GATA factors required for PrE-like differentiation, and thereby control the proportion of cells differentiating along this lineage. Our findings can be explained by a simple mutual repression circuit modulated by FGF/MAPK signaling. This might be a general network architecture to integrate the activity of signal transduction pathways and transcriptional regulators, and serve to balance proportions of cell fates in several contexts. PMID:26511924

  3. Weaning Induced Hepatic Oxidative Stress, Apoptosis, and Aminotransferases through MAPK Signaling Pathways in Piglets

    PubMed Central

    Luo, Zhen; Zhu, Wei; Guo, Qi; Luo, Wenli; Zhang, Jing; Xu, Weina

    2016-01-01

    This study investigated the effects of weaning on the hepatic redox status, apoptosis, function, and the mitogen-activated protein kinase (MAPK) signaling pathways during the first week after weaning in piglets. A total of 12 litters of piglets were weaned at d 21 and divided into the weaning group (WG) and the control group (CG). Six piglets from each group were slaughtered at d 0 (d 20, referred to weaning), d 1, d 4, and d 7 after weaning. Results showed that weaning significantly increased the concentrations of hepatic free radicals H2O2 and NO, malondialdehyde (MDA), and 8-hydroxy-2′-deoxyguanosine (8-OHdG), while significantly decreasing the inhibitory hydroxyl ability (IHA) and glutathione peroxidase (GSH-Px), and altered the level of superoxide dismutase (SOD). The apoptosis results showed that weaning increased the concentrations of caspase-3, caspase-8, caspase-9 and the ratio of Bax/Bcl-2. In addition, aspartate aminotransferase transaminase (AST) and alanine aminotransferase (ALT) in liver homogenates increased after weaning. The phosphorylated JNK and ERK1/2 increased, while the activated p38 initially decreased and then increased. Our results suggested that weaning increased the hepatic oxidative stress and aminotransferases and initiated apoptosis, which may be related to the activated MAPK pathways in postweaning piglets. PMID:27807471

  4. MicroRNA-181a Regulates Apoptosis and Autophagy Process in Parkinson’s Disease by Inhibiting p38 Mitogen-Activated Protein Kinase (MAPK)/c-Jun N-Terminal Kinases (JNK) Signaling Pathways

    PubMed Central

    Liu, Ying; Song, Yanfeng; Zhu, Xiaotun

    2017-01-01

    Background microRNA (miR)-181a has been reported to be downregulated in Parkinson’s disease (PD), but the regulatory mechanism of miR-181a on neuron apoptosis and autophagy is still poorly understood. We aimed to investigate the neuroprotective effects of miR-181a on PD in vitro. Material/Methods Human SK-N-SH neuroblastoma cells were incubated with different concentrations of 1-methyl-4-phenylpyridinium ion (MPP+) to induce the PD model. The expression of miR-181a was then analyzed. After transfection with miR-181a mimic or scramble following MPP+ treatment, the expression of autophagy protein markers (LC3II, LC3I, and Beclin 1) and p38 mitogen-activated protein kinase (MAPK)/c-Jun N-terminal kinases (JNK) signaling proteins (p-p38, p38, p-JNK, and JNK) and cell apoptosis were detected. Furthermore, the cells were transfected with miR-181a inhibitor and cultured in the presence or absence of p38 inhibitor SB203582 or JNK inhibitor SP600125, and the cell apoptosis was tested again. Results The expression of miR-181a was gradually decreased with the increase of MPP+ concentration (P<0.05, P<0.01, or P<0.001). Overexpression of miR-181a significantly decreased the LC3II/LC3I ratio, Beclin 1 expression, cell apoptosis, and the expression of p-p38 and p-JNK compared to the MPP+ + miR-181a scramble group (all P<0.05). In addition, we observed that SB203582 or SP600125 showed no effects on cell apoptosis, but the effects of miR-181a inhibitor on cell apoptosis were reversed by administration of SB203582 or SP600125 compared to the scramble group (P<0.05). Conclusions Our results suggest that miR-181a regulates apoptosis and autophagy in PD by inhibiting the p38 MAPK/JNK pathway. PMID:28365714

  5. MicroRNA-181a Regulates Apoptosis and Autophagy Process in Parkinson's Disease by Inhibiting p38 Mitogen-Activated Protein Kinase (MAPK)/c-Jun N-Terminal Kinases (JNK) Signaling Pathways.

    PubMed

    Liu, Ying; Song, Yanfeng; Zhu, Xiaotun

    2017-04-02

    BACKGROUND microRNA (miR)-181a has been reported to be downregulated in Parkinson's disease (PD), but the regulatory mechanism of miR-181a on neuron apoptosis and autophagy is still poorly understood. We aimed to investigate the neuroprotective effects of miR-181a on PD in vitro. MATERIAL AND METHODS Human SK-N-SH neuroblastoma cells were incubated with different concentrations of 1-methyl-4-phenylpyridinium ion (MPP+) to induce the PD model. The expression of miR-181a was then analyzed. After transfection with miR-181a mimic or scramble following MPP+ treatment, the expression of autophagy protein markers (LC3II, LC3I, and Beclin 1) and p38 mitogen-activated protein kinase (MAPK)/c-Jun N-terminal kinases (JNK) signaling proteins (p-p38, p38, p-JNK, and JNK) and cell apoptosis were detected. Furthermore, the cells were transfected with miR-181a inhibitor and cultured in the presence or absence of p38 inhibitor SB203582 or JNK inhibitor SP600125, and the cell apoptosis was tested again. RESULTS The expression of miR-181a was gradually decreased with the increase of MPP+ concentration (P<0.05, P<0.01, or P<0.001). Overexpression of miR-181a significantly decreased the LC3II/LC3I ratio, Beclin 1 expression, cell apoptosis, and the expression of p-p38 and p-JNK compared to the MPP+ + miR-181a scramble group (all P<0.05). In addition, we observed that SB203582 or SP600125 showed no effects on cell apoptosis, but the effects of miR-181a inhibitor on cell apoptosis were reversed by administration of SB203582 or SP600125 compared to the scramble group (P<0.05). CONCLUSIONS Our results suggest that miR-181a regulates apoptosis and autophagy in PD by inhibiting the p38 MAPK/JNK pathway.

  6. CoCl2 induces protective events via the p38-MAPK signalling pathway and ANP in the perfused amphibian heart.

    PubMed

    Gaitanaki, Catherine; Kalpachidou, Theodora; Aggeli, Ioanna-Katerina S; Papazafiri, Panagiota; Beis, Isidoros

    2007-07-01

    Mitogen-activated protein kinases (MAPKs) constitute one of the most important intracellular signalling pathways. In particular, the p38-MAPK subfamily is known to be activated under various stressful conditions, such as mechanical or oxidative stress. Furthermore, cobalt chloride (CoCl2) has been shown to mimic hypoxic responses in various cell lines and cause overproduction of reactive oxygen species (ROS). In the current study, we investigated the effect of CoCl2 on p38-MAPK signalling pathway in the perfused Rana ridibunda heart. Immunoblot analysis of the phosphorylated, and thus activated, form of p38-MAPK revealed that maximum phosphorylation was attained at 500 micromol l(-1) CoCl2. A similar profile was observed for MAPKAPK2 and Hsp27 phosphorylation (direct and indirect p38-MAPK substrates, respectively). Time course analysis of p38-MAPK phosphorylation pattern showed that the kinase reached its peak within 15 min of treatment with 500 micromol l(-1) CoCl2. Similar results were obtained for Hsp27 phosphorylation. In the presence of the antioxidants Trolox or Lipoic acid, p38-MAPK CoCl2-induced phosphorylation was attenuated. Analogous results were obtained for Hsp27 and MAPKAPK2. In parallel, mRNA levels of the ANP gene, a hormone whose transcriptional regulation has previously been shown to be regulated by p38-MAPK, were examined (semi-quantitative ratiometric RT-PCR). CoCl2 treatment significantly increased ANP mRNA levels, whereas, in the presence of antioxidants, the transcript levels returned to basal values. All the above data indicate that CoCl2 stimulates compensatory mechanisms involving the p38-MAPK signalling cascade along with ANP.

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

    PubMed

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

    2015-11-01

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

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

    PubMed Central

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

    2016-01-01

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

  9. p38 MAPK and PI3K/AKT Signalling Cascades inParkinson’s Disease

    PubMed Central

    Jha, Saurabh Kumar; Jha, Niraj Kumar; Kar, Rohan; Ambasta, Rashmi K; Kumar, Pravir

    2015-01-01

    Parkinson's disease (PD) is a chronic neurodegenerative condition which has the second largest incidence rate among all other neurodegenerative disorders barring Alzheimer's disease (AD). Currently there is no cure and researchers continue to probe the therapeutic prospect in cell cultures and animal models of PD. Out of the several factors contributing to PD prognosis, the role of p38 MAPK (Mitogen activated protein-kinase) and PI3K/AKT signalling module in PD brains is crucial because the impaired balance between the pro- apoptotic and anti-apoptotic pathways trigger unwanted phenotypes such as microglia activation, neuroinflammation, oxidative stress and apoptosis. These factors continue challenging the brain homeostasis in initial stages thereby essentially assisting the dopaminergic (DA) neurons towards progressive degeneration in PD. Neurotherapeutics against PD shall then be targeted against the misregulated accomplices of the p38 and PI3K/AKT cascades. In this review, we have outlined many such established mechanisms involving the p38 MAPK and PI3K/AKT pathways which can offer therapeutic windows for the rectification of aberrant DA neuronal dynamics in PD brains. PMID:26261796

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

    PubMed Central

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

    2013-01-01

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

  11. CXCL12/CXCR4 chemokine signaling in spinal glia induces pain hypersensitivity through MAPKs-mediated neuroinflammation in bone cancer rats.

    PubMed

    Hu, Xue-Ming; Liu, Yan-Nan; Zhang, Hai-Long; Cao, Shou-Bin; Zhang, Ting; Chen, Li-Ping; Shen, Wen

    2015-02-01

    The activation of MAPK pathways in spinal cord and subsequent production of proinflammatory cytokines in glial cells contribute to the development of spinal central sensitization, the basic mechanism underlying bone cancer pain (BCP). Our previous study showed that spinal CXCL12 from astrocytes mediates BCP generation by binding to CXCR4 in both astrocyters and microglia. Here, we verified that CXCL12/CXCR4 signaling contributed to BCP through a MAPK-mediated mechanism. In naïve rats, a single intrathecal administration of CXCL12 considerably induced pain hyperalgesia and phosphorylation expression of spinal MAPK members (including extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase), which could be partially prevented by pre-treatment with CXCR4 inhibitor AMD3100. This CXCL12-induced hyperalgesia was also reduced by MAPK inhibitors. In bone cancer rats, tumor cell inoculation into the tibial cavity caused prominent and persistent pain hyperalgesia, and associated with up-regulation of CXCL12 and CXCR4, activation of glial cells, phosphorylation of MAPKs, and production of proinflammatory cytokines in the spinal cord. These tumor cell inoculation-induced behavioral and neurochemical alterations were all suppressed by blocking CXCL12/CXCR4 signaling or MAPK pathways. Taken together, these results demonstrate that spinal MAPK pathways mediated CXCL12/CXCR4-induced pain hypersensitivity in bone cancer rats, which could be druggable targets for alleviating BCP and glia-derived neuroinflammation. Following tumor cell inoculation, chemokine CXCL12 from astrocytes spreads around the spinal environment, resulting in functional activation of CXCR4-expressing astrocytes and microglia. Once glia are activated, they may initiate MAPK (mitogen-activated protein kinase) pathways, and subsequently produce proinflammatory cytokines and chemokines. Among them, CXCL12 could reinforce the astrocytic and microglial activation in autocrine and paracrine manners

  12. Morin Attenuates Ovalbumin-Induced Airway Inflammation by Modulating Oxidative Stress-Responsive MAPK Signaling

    PubMed Central

    Ma, Yuan; Ge, Ai; Zhu, Wen; Liu, Ya-Nan; Ji, Ning-Fei; Zha, Wang-Jian; Zhang, Jia-Xiang; Zeng, Xiao-Ning

    2016-01-01

    Asthma is one of the most common inflammatory diseases characterized by airway hyperresponsiveness, inflammation, and remodeling. Morin, an active ingredient obtained from Moraceae plants, has been demonstrated to have promising anti-inflammatory activities in a range of disorders. However, its impacts on pulmonary diseases, particularly on asthma, have not been clarified. This study was designed to investigate whether morin alleviates airway inflammation in chronic asthma with an emphasis on oxidative stress modulation. In vivo, ovalbumin- (OVA-) sensitized mice were administered with morin or dexamethasone before challenge. Bronchoalveolar lavage fluid (BALF) and lung tissues were obtained to perform cell counts, histological analysis, and enzyme-linked immunosorbent assay. In vitro, human bronchial epithelial cells (BECs) were challenged by tumor necrosis factor alpha (TNF-α). The supernatant was collected for the detection of the proinflammatory proteins, and the cells were collected for reactive oxygen species (ROS)/mitogen-activated protein kinase (MAPK) evaluations. Severe inflammatory responses and remodeling were observed in the airways of the OVA-sensitized mice. Treatment with morin dramatically attenuated the extensive trafficking of inflammatory cells into the BALF and inhibited their infiltration around the respiratory tracts and vessels. Morin administration also significantly suppressed goblet cell hyperplasia and collagen deposition/fibrosis and dose-dependently inhibited the OVA-induced increases in IgE, TNF-α, interleukin- (IL-) 4, IL-13, matrix metalloproteinase-9, and malondialdehyde. In human BECs challenged by TNF-α, the levels of proteins such as eotaxin-1, monocyte chemoattractant protein-1, IL-8 and intercellular adhesion molecule-1, were consistently significantly decreased by morin. Western blotting and the 2′,7′-dichlorofluorescein assay revealed that the increases in intracellular ROS and MAPK phosphorylation were abolished by

  13. miR-217 regulates tumor growth and apoptosis by targeting the MAPK signaling pathway in colorectal cancer

    PubMed Central

    Zhang, Nan; Lu, Canrong; Chen, Lin

    2016-01-01

    MicroRNA (miR)-217 has been reported to participate in carcinogenesis and tumor progression in several cancers; however, its expression and biological functions in colorectal cancer (CRC) are still unclear. The present study demonstrated that miR-217 expression was significantly higher in matched adjacent noncancerous tissues than in CRC tissues (P<0.001). In addition, it was observed that low-grade CRC exhibited greater expression of miR-217 compared with high-grade CRC (P<0.05). Kaplan-Meier survival and Cox regression analyses revealed that overall survival rates were significantly poorer in the low-expression group relative to the high-expression group (P<0.005). Next, a potential miR-217 target, mitogen-activated protein kinase (MAPK) 1, was identified. Upregulation of miR-217 could significantly downregulate MAPK1 expression. CRC cells overexpressing miR-217 exhibited cell growth inhibition by significant enhancement of apoptosis in vitro. The present study further investigated the MAPK signaling pathway to verify the mechanisms, and revealed that KRAS and Raf-1 expression was downregulated in miR-217-overexpressing RKO cells. Taken together, our results revealed that miR-217 inhibits tumor growth and enhances apoptosis in CRC, and that this is associated with the downregulation of MAPK signaling. These results indicate that miR-217 is a promising therapeutic target for the treatment of CRC. PMID:28105166

  14. Ste50 adaptor protein governs sexual differentiation of Cryptococcus neoformans via the pheromone response MAPK signaling pathway

    PubMed Central

    Jung, Kwang-Woo; Kim, Seo-Young; Okagaki, Laura H.; Nielsen, Kirsten; Bahn, Yong-Sun

    2010-01-01

    The mitogen-activated protein kinase (MAPK) pathways control diverse cellular functions in pathogenic fungi, including sexual differentiation, stress-response, and maintenance of cell wall integrity. Here we characterized a C. neoformans gene, which is homologous to the yeast Ste50 that is known to play an important role in mating pheromone response and stress response as an adaptor protein to the Ste11 MAPK kinase kinase in Saccharomyces cerevisiae. The C. neoformans Ste50 was not involved in any of the stress responses or virulence factor production (capsule and melanin) that are controlled by the HOG and Ras/cAMP signaling pathways. However, Ste50 was required for mating in both serotype A and serotype D C. neoformans strains. The ste50Δ mutant was completely defective in cell-cell fusion and mating pheromone production. Double mutation of the STE50 gene blocked increased production of pheromone and the hyper-filamentation phenotype of cells deleted of the CRG1 gene, which encodes the RGS protein that negatively regulates pheromone responsive G-protein signaling via the MAPK pathway. Regardless of the presence of the basidiomycota-specific SH3 domains of Ste50 that are known to be required for full virulence of Ustilago maydis, Ste50 was dispensable for virulence of C. neoformans in a murine model of cryptococcosis. In conclusion, the Ste50 adaptor protein controls sexual differentiation of C. neoformans via the pheromone-responsive MAPK pathway but is not required for virulence. PMID:20971202

  15. Skeletal muscle cell activation by low-energy laser irradiation: a role for the MAPK/ERK pathway.

    PubMed

    Shefer, G; Oron, U; Irintchev, A; Wernig, A; Halevy, O

    2001-04-01

    Low-energy laser irradiation (LELI) has been shown to promote skeletal muscle regeneration in vivo and to activate skeletal muscle satellite cells, enhance their proliferation and inhibit differentiation in vitro. In the present study, LELI, as well as the addition of serum to serum-starved myoblasts, restored their proliferation, whereas myogenic differentiation remained low. LELI induced mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MAPK/ERK) phosphorylation with no effect on its expression in serum-starved myoblasts. Moreover, a specific MAPK kinase inhibitor (PD098059) inhibited the LELI- and 10% serummediated ERK1/2 activation. However, LELI did not affect Jun N-terminal kinase (JNK) or p38 MAPK phosphorylation or protein expression. Whereas a 3-sec irradiation induced ERK1/2 phosphorylation, a 12-sec irradiation reduced it, again with no effect on JNK or p38. Moreover, LELI had distinct effects on receptor phosphorylation: it caused phosphorylation of the hepatocyte growth factor (HGF) receptor, previously shown to activate the MAPK/ERK pathway, whereas no effect was observed on tumor suppressor necrosis alpha (TNF-alpha) receptor which activates the p38 and JNK pathways. Therefore, by specifically activating MAPK/ERK, but not JNK and p38 MAPK enzymes, probably by specific receptor phosphorylation, LELI induces the activation and proliferation of quiescent satellite cells and delays their differentiation.

  16. Differential contribution of hypothalamic MAPK activity to anxiety-like behaviour in virgin and lactating rats.

    PubMed

    Jurek, Benjamin; Slattery, David A; Maloumby, Rodrigue; Hillerer, Katharina; Koszinowski, Sophie; Neumann, Inga D; van den Burg, Erwin H

    2012-01-01

    The c-Raf - MEK1/2 - ERK1/2 mitogen-activated protein kinase (MAPK) intracellular signalling cascade in neurons plays important roles in the control of a variety of behaviours, including social behaviours and anxiety. These roles partially overlap with those described for oxytocin (OXT), and it has been shown that OXT activates the MAPK pathway in the hypothalamus (of male), and hippocampus (of female) rats. Here, by combining behavioural (light/dark box) and biochemical analyses (western blotting), we tested two hypotheses: (i) that OXT is anxiolytic within the hypothalamus of females, and (ii) that this effect, as well as that of lactation-associated anxiolysis, depends on the recruitment of the MAPK pathway. We found that, when injected bilaterally into the hypothalamic paraventricular nucleus (PVN), OXT decreased anxiety-like behaviour in virgins, and that this effect depended on phosphorylation of MEK1/2. MAPK pathway activation in lactation was evident by high phosphorylated (p) MEK1/2 levels, and nuclear translocation of ERK1. The high pMEK1/2 levels were necessary for the anxiolytic phenotype typically observed during lactation. Interestingly, exogenous OXT in lactating rats reduced pMEK1/2 levels without a concomitant effect on anxiety, indicating that OXT receptor activation can lead to recruitment of additional intracellular pathways to modulate MEK activity. Still other pathways could include MEK, but without subsequent activation of ERK, as we did not observe any increase in OXT-induced ERK phosphorylation. Together the results demonstrate that the MAPK pathway, especially MEK1/2, is critically involved in the regulation of anxiety-like behaviour in female rats.

  17. Adipocyte-derived PAMM suppresses macrophage inflammation by inhibiting MAPK signalling

    PubMed Central

    Guo, Fang; He, Hui; Fu, Zhi-Chao; Huang, Shengping; Chen, Tingtao; Papasian, Christopher J.; Morse, Leslie R.; Xu, Yan; Battaglino, Ricardo A.; Yang, Xiao-Feng; Jiang, Zhisheng; Xin, Hong-Bo; Fu, Mingui

    2016-01-01

    Macrophages within adipose tissue play a key role in mediating inflammatory responses in adipose tissue that are associated with obesity-related metabolic complications. In an effort to identify novel proteins secreted from adipocytes that may negatively regulate macrophage inflammation, we found that peroxiredoxin (PRX)-like 2 activated in M-CSF stimulated monocytes (PAMM), a CXXC-type PRX-like 2 domain-containing redox regulatory protein, is a novel secreted protein with potent anti-inflammatory properties. PAMM is secreted from mature human adipocytes but not preadipocytes. Overexpression of PAMM significantly attenuated lipopolysaccharide (LPS)-induced macrophage inflammation. Incubation of macrophages with adipocyte-conditional medium treated with anti-PAMM antibody significantly enhanced LPS-induced interleukin-12 (IL-12) expression in Raw264.7 cells. In addition, incubation of Raw264.7 cells with purified PAMM protein had a similar anti-inflammatory effect. Moreover, forced expression of PAMM in Raw264.7 cells resulted in decreased LPS-induced ERK1/2, p38 and c-Jun N-terminal kinase (JNK) phosphorylation, suggesting that PAMM exerted the anti-inflammatory function probably by suppressing the mitogen-activated protein kinase (MAPK) signalling pathway. Mutations in the CXXC motif of PAMM that suppressed its anti-redox activity were still able to suppress production of inflammatory cytokines in LPS-stimulated macrophages, suggesting that PAMM’s anti-inflammatory properties may be independent of its antioxidant properties. Finally, PAMM was highly expressed in both white (WAT) and brown adipose tissues (BAT) and further increased in obesity status. Our results suggest that adipocyte-derived PAMM may suppress macrophage activation by inhibiting MAPK signalling pathway. PMID:26438880

  18. Solution phase parallel synthesis and evaluation of MAPK inhibitory activities of close structural analogues of a Ras pathway modulator.

    PubMed

    Lu, Yingchun; Sakamuri, Sukumar; Chen, Quin-Zene; Keng, Yen-Fang; Khazak, Vladimir; Illgen, Katrin; Schabbert, Silke; Weber, Lutz; Menon, Sanjay R

    2004-08-02

    A solution phase parallel synthesis approach was undertaken to rapidly explore the structure-activity relationship of an inhibitor of the Ras/Raf protein interaction identified from a small molecule compound library. Evaluation of the MAPK pathway signaling inhibitory activity of the synthesized analogues as well as their antiproliferative activity and ability to inhibit soft agar growth were performed.

  19. Signaling events initiated by kappa opioid receptor activation: quantification and immunocolocalization using phospho-selective KOR, p38 MAPK, and K(IR) 3.1 antibodies.

    PubMed

    Lemos, Julia C; Roth, Clarisse A; Chavkin, Charles

    2011-01-01

    Psychiatric disorders including anxiety, depression, and addiction are both precipitated and exacerbated by severe or chronic stress exposure. While acutely, stress responses are adaptive, repeated exposure to stress can dysregulate the brain in such a way as to predispose the organism to both physiological and mental illness. Understanding the neuronal chemicals, cell types, and circuits involved in both normal and pathological stress responses are essential in developing new therapeutics for psychiatric diseases. Varying degrees of stressor exposure cause the release of a constellation of chemicals, including neuropeptides such as dynorphin. Neuropeptidergic release can be very difficult to directly measure with adequate spatial and temporal resolution. Moreover, the downstream consequences following release and receptor binding are numerous and also difficult to measure with cellular resolution. Following repeated stressor exposure, dynorphin is released, binds to the kappa opioid receptor (KOR), and causes activation of KOR. Agonist-activated KOR becomes a substrate for G protein receptor kinase (GRK), which phosphorylates the Ser369 residue at the C-terminal tail of the receptor in the first step in the β-Arrestin-dependent desensitization cascade. Through the use of phospho--selective antibodies developed and validated in the laboratory, we have the tools, to assess with fine cellular resolution, the strength of behavioral stimulus required for release, time course of the release, and regional location of release. We have gone on to show that following KOR activation, both ERK 1/2 and p38 MAP kinase phosphorylation are increased through use of commercially available phospho-selective antibodies. Finally, we have identified that one effector of KOR/p38MAP kinase is K(IR) 3.1 and have developed a phospho-selective antibody against the Y12 motif of this channel. Much like KOR and p38 MAP kinase, phosphorylation of this potassium channel increases following

  20. 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

    2017-02-03

    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.

  1. Rewiring yeast osmostress signalling through the MAPK network reveals essential and non-essential roles of Hog1 in osmoadaptation

    PubMed Central

    Babazadeh, Roja; Furukawa, Takako; Hohmann, Stefan; Furukawa, Kentaro

    2014-01-01

    Mitogen-activated protein kinases (MAPKs) have a number of targets which they regulate at transcriptional and post-translational levels to mediate specific responses. The yeast Hog1 MAPK is essential for cell survival under hyperosmotic conditions and it plays multiple roles in gene expression, metabolic regulation, signal fidelity and cell cycle regulation. Here we describe essential and non-essential roles of Hog1 using engineered yeast cells in which osmoadaptation was reconstituted in a Hog1-independent manner. We rewired Hog1-dependent osmotic stress-induced gene expression under the control of Fus3/Kss1 MAPKs, which are activated upon osmostress via crosstalk in hog1Δ cells. This approach revealed that osmotic up-regulation of only two Hog1-dependent glycerol biosynthesis genes, GPD1 and GPP2, is sufficient for successful osmoadaptation. Moreover, some of the previously described Hog1-dependent mechanisms appeared to be dispensable for osmoadaptation in the engineered cells. These results suggest that the number of essential MAPK functions may be significantly smaller than anticipated and that knockout approaches may lead to over-interpretation of phenotypic data. PMID:24732094

  2. Suppression of Inflammatory Responses by Dihydromyricetin, a Flavonoid from Ampelopsis grossedentata, via Inhibiting the Activation of NF-κB and MAPK Signaling Pathways.

    PubMed

    Hou, X L; Tong, Q; Wang, W Q; Shi, C Y; Xiong, W; Chen, J; Liu, X; Fang, J G

    2015-07-24

    Ampelopsis grossedentata, an indigenous plant in southern China, has been used for treating pharyngitis in traditional Chinese medicine for hundreds of years. In this study, we explored the anti-inflammatory activity of dihydromyricetin (1), its major bioactive component, and the underlying mechanism of this action. We demonstrated that 1 suppressed the levels of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) as well as increased the level of the anti-inflammatory cytokine interleukin-10 (IL-10) in lipopolysaccharide (LPS)-treated mice. Moreover, 1 was found to markedly inhibit the production of nitric oxide (NO) and the levels of TNF-α, IL-1β, and IL-6, whereas it increased the level of IL-10 in LPS-induced RAW 264.7 macrophage cells. Compound 1 also reduced the protein expression of inducible nitric oxide synthase (iNOS), TNF-α, and cyclooxygenase-2 (COX-2) in macrophage cells. Furthermore, 1 suppressed the phosphorylation of NF-kappa B (NF-κB) and IκBα as well as the phosphorylation of p38 and JNK but not ERK1/2 in LPS-stimulated macrophages. Taken together, the present results suggest that 1 exerts its topical anti-inflammatory action through suppressing the activation of NF-κB and the phosphorylation of p38 and JNK. Thus, 1 may be a potentially useful therapeutic agent for inflammatory-related diseases.

  3. Activation of PPARγ suppresses proliferation and induces apoptosis of esophageal cancer cells by inhibiting TLR4-dependent MAPK pathway.

    PubMed

    Wu, Kai; Yang, Yang; Liu, Donglei; Qi, Yu; Zhang, Chunyang; Zhao, Jia; Zhao, Song

    2016-07-12

    Although substantial studies on peroxisome proliferator-activated receptor g (PPARg) have focused on the mechanisms by which PPARg regulates glucose and lipid metabolism, recent reports have suggested that PPARg shows tumorigenic or antitumorigenic effects. The roles and mechanisms of PPARg activation in esophageal cancer remain unclarified. EC109 and TE10 esophageal cancer cells were treated with 0, 10, 20 and 40 mM of PPARg agonist rosiglitazone (RGZ) for 24, 48, and 72 h, and the cell viability and apoptosis were detected using methyl thiazolyl tetrazolium (MTT) assay and Flow cytometric (FCM) analysis, respectively. Moreover, the effects of inhibition of PPARg by antagonist or specific RNA interference on cell viability, apoptosis, the Toll-like receptor 4 (TLR4) and mitogen-activated protein kinase (MAPK) pathways were evaluated. Additionally, the effect of TLR4 signaling on the MAPK pathway, cell viability and apoptosis was assessed. The results showed that RGZ suppressed proliferation and induced apoptosis of esophageal cancer cells, which could be partly restored by inactivation of PPARg. RGZ suppressed the MAPK and TLR4 pathways, and the inhibitory effect could be counteracted by PPARg antagonist or specific RNA interference. We also suggested that MAPK activation was regulated by the TLR4 pathway and that blocking the TLR4 and MAPK pathways significantly suppressed proliferation and induced apoptosis of esophageal cancer cells. In conclusion, our data suggested that activation of PPARg suppressed proliferation and induced apoptosis of esophageal cancer cells by inhibiting TLR4-dependent MAPK pathway.

  4. Regulation of MAPK/ERK Signaling and Photic Entrainment of the Suprachiasmatic Nucleus Circadian Clock by Raf Kinase Inhibitor Protein

    PubMed Central

    Antoun, Ghadi; Cannon, Pascale Bouchard; Cheng, Hai-Ying Mary

    2013-01-01

    Activation of the MAPK/ERK signaling cascade in the suprachiasmatic nucleus (SCN) is a key event that couples light to circadian clock entrainment. However, we do not fully understand the mechanisms that shape the properties of MAPK/ERK signaling in the SCN, and how these mechanisms may influence overt circadian rhythms. Here we show that Raf kinase inhibitor protein (RKIP) controls the kinetics of light-induced MAPK/ERK activity in the SCN and photic entrainment of behavioral rhythms. Light triggers robust phosphorylation of RKIP in the murine SCN and dissociation of RKIP and c-Raf. Overexpression of a nonphosphorylatable form of RKIP in the SCN of transgenic mice blocks light-induced ERK1/2 activation in the SCN and severely dampens light-induced phase delays in behavioral rhythms. Conversely, in RKIP knock-out (RKIP−/−) mice, light-induced ERK1/2 activity in the SCN is prolonged in the early and late subjective night, resulting in augmentation of the phase-delaying and -advancing effects of light. Reentrainment to an advancing light cycle was also accelerated in RKIP−/− mice. In relation to the molecular clockwork, genetic deletion of RKIP potentiated light-evoked PER1 and PER2 protein expression in the SCN in the early night. Additionally, RKIP−/− mice displayed enhanced transcriptional activation of mPeriod1 and the immediate early gene c-Fos in the SCN in response to a phase-delaying light pulse. Collectively, our data reveal an important role of RKIP in the regulation of MAPK/ERK signaling in the SCN and photic entrainment of the SCN clock. PMID:22492043

  5. Complement C5a-C5aR interaction enhances MAPK signaling pathway activities to mediate renal injury in trichloroethylene sensitized BALB/c mice.

    PubMed

    Zhang, Jia-xiang; Zha, Wan-sheng; Ye, Liang-ping; Wang, Feng; Wang, Hui; Shen, Tong; Wu, Chang-hao; Zhu, Qi-xing

    2016-02-01

    We have previously shown complement activation as a possible mechanism for trichloroethylene (TCE) sensitization, leading to multi-organ damage including the kidneys. In particular, excessive deposition of C5 and C5b-9-the membrane attack complex, which can generate significant tissue damage, was observed in the kidney tissue after TCE sensitization. The present study tested the hypothesis that anaphylatoxin C5a binding to its receptor C5aR mediates renal injury in TCE-sensitized BALB/c mice. BALB/c mice were sensitized through skin challenge with TCE, with or without pretreatment by the C5aR antagonist W54011. Kidney histopathology and the renal functional test were performed to assess renal injury, and immunohistochemistry and fluorescent labeling were carried out to assess C5a and C5aR expressions. TCE sensitization up-regulated C5a and C5aR expressions in kidney tissue, generated inflammatory infiltration, renal tubule damage, glomerular hypercellularity and impaired renal function. Antagonist pretreatment blocked C5a binding to C5aR and attenuated TCE-induced tissue damage and renal dysfunction. TCE sensitization also caused the deposition of major pro-inflammatory cytokines IL-2, TNF-α and IFN-γ in the kidney tissue (P < 0.05); this was accompanied by increased expression of P-p38, P-ERK and P-JNK proteins (P < 0.05). Pretreatment with the C5aR antagonist attenuated the increase of expression of P-p38, P-ERK and P-JNK proteins (P < 0.05) and also consistently reduced the TCE sensitization-induced increase of IL-2, TNF-α and IFN-γ (P < 0.05). These data identify C5a binding to C5aR, MAP kinase activation, and inflammatory cytokine release as a novel mechanism for complement-mediated renal injury by sensitization with TCE or other environmental chemicals.

  6. Elevated COX-2 Expression Promotes Angiogenesis Through EGFR/p38-MAPK/Sp1-Dependent Signalling in Pancreatic Cancer.

    PubMed

    Hu, Hai; Han, Ting; Zhuo, Meng; Wu, Lei-Lei; Yuan, Cuncun; Wu, Lixia; Lei, Wang; Jiao, Feng; Wang, Li-Wei

    2017-03-28

    Cyclooxygenase-2 (COX-2) was stated to be overexpression in various human malignancies associating with angiogenesis, metastasis and chemoresistence. Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease displaying many of these characteristics. A common abnormality of PDAC is overexpression of specificity protein-1 (Sp1), which was said to correlate with malignant phenotypes of human cancers. Using RNA-seq data from The Cancer Genome Atlas (TCGA), we found that Sp1 expression was positively correlated with that of COX-2 in PDAC, and that the inhibition or overexpression of Sp1 in PDAC cells leads to decreased or elevated COX-2 expression. Luciferase reporter gene and chromatin immunoprecipitation (ChIP) assays revealed that elevated transcription of COX-2 requires Sp1 binding to sequence positions around -245/-240 of COX-2 promoter. Activated epidermal growth factor receptor (EGFR) and downstream p38 mitogen-activated protein kinase (p38-MAPK) were also profoundly altered in PDAC. The inhibition of EGFR/p38-MAPK signaling resulted in reduced Sp1 activation, decreased COX-2 and vascular endothelial growth factor (VEGF) expression. Thus, Sp1 could transcriptionally activate COX-2 expression in a process relies on activated EGFR/p38-MAPK signaling. Finally, we found that the inhibition of COX-2 leads to decreased angiogenesis in a process dependent on VEGF, which link COX-2 to angiogenesis in PDAC.

  7. Antiallergic Activity of Ethanol Extracts of Arctium lappa L. Undried Roots and Its Active Compound, Oleamide, in Regulating FcεRI-Mediated and MAPK Signaling in RBL-2H3 Cells.

    PubMed

    Yang, Woong-Suk; Lee, Sung Ryul; Jeong, Yong Joon; Park, Dae Won; Cho, Young Mi; Joo, Hae Mi; Kim, Inhye; Seu, Young-Bae; Sohn, Eun-Hwa; Kang, Se Chan

    2016-05-11

    The antiallergic potential of Arctium lappa L. was investigated in Sprague-Dawley rats, ICR mice, and RBL-2H3 cells. Ethanol extract (90%) of A. lappa (ALE, 100 μg/mL) inhibited the degranulation rate by 52.9%, determined by the level of β-hexosaminidase. ALE suppressed passive cutaneous anaphylaxis (PCA) in rats and attenuated anaphylaxis and histamine release in mice. To identify the active compound of ALE, we subsequently fractionated and determined the level of β-hexosaminidase in all subfractions. Oleamide was identified as an active compound of ALE, which attenuated the secretion of histamine and the production of tumor necrosis factor (TNF)-α and interleukin-4 (IL-4) in cells treated with compound 48/80 or A23187/phorbol myristate acetate (PMA). Oleamide suppressed FcεRI-tyrosine kinase Lyn-mediated pathway, c-Jun N-terminal kinases (JNK/SAPK), and p38 mitogen-activated protein kinases (p38-MAPKs). These results showed that ALE and oleamide attenuated allergic reactions and should serve as a platform to search for compounds with antiallergic activity.

  8. Differential regulation of EGFR-MAPK signaling by deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) in colon cancer.

    PubMed

    Centuori, Sara M; Martinez, Jesse D

    2014-10-01

    A high-fat diet coincides with increased levels of bile acids. This increase in bile acids, particularly deoxycholic acid (DCA), has been strongly associated with the development of colon cancer. Conversely, ursodeoxycholic acid (UDCA) may have chemopreventive properties. Although structurally similar, DCA and UDCA present different biological and pathological effects in colon cancer progression. The differential regulation of cancer by these two bile acids is not yet fully understood. However, one possible explanation for their diverging effects is their ability to differentially regulate signaling pathways involved in the multistep progression of colon cancer, such as the epidermal growth factor receptor (EGFR)-mitogen-activated protein kinase (MAPK) pathway. This review will examine the biological effects of DCA and UDCA on colon cancer development, as well as the diverging effects of these bile acids on the oncogenic signaling pathways that play a role in colon cancer development, with a particular emphasis on bile acid regulation of the EGFR-MAPK pathway.

  9. Differential roles of MAPK-Erk1/2 and MAPK-p38 in insulin or insulin-like growth factor-I (IGF-I) signaling pathways for progesterone production in human ovarian cells.

    PubMed

    Seto-Young, D; Avtanski, D; Varadinova, M; Park, A; Suwandhi, P; Leiser, A; Parikh, G; Poretsky, L

    2011-06-01

    Insulin and insulin like-growth factor-I (IGF-I) participate in the regulation of ovarian steroidogenesis. In insulin resistant states ovaries remain sensitive to insulin because insulin can activate alternative signaling pathways, such as phosphatidylinositol-3-kinase (PI-3 kinase) and mitogen-activated protein-kinase (MAPK) pathways, as well as insulin receptors and type 1 IGF receptors. We investigated the roles of MAPK-Erk1/2 and MAPK-p38 in insulin and IGF-I signaling pathways for progesterone production in human ovarian cells. Human ovarian cells were cultured in tissue culture medium in the presence of varying concentrations of insulin or IGF-I, with or without PD98059, a specific MAPK-Erk1/2 inhibitor, with or without SB203580, a specific MAPK-p38 inhibitor or with or without a specific PI-3-kinase inhibitor LY294002. Progesterone concentrations were measured using radioimmunoassay. PD98059 alone stimulated progesterone production in a dose-dependent manner by up to 65% (p<0.001). Similarly, LY294002 alone stimulated progesterone production by 13-18% (p<0.005). However, when used together, PD98059 and LY294002 inhibited progesterone production by 17-20% (p<0.001). SB203580 alone inhibited progesterone production by 20-30% (p<0.001). Insulin or IGF-I alone stimulated progesterone production by 40-60% (p<0.001). In insulin studies, PD98059 had no significant effect on progesterone synthesis while SB203580 abolished insulin-induced progesterone production. Either PD98059 or SB203580 abolished IGF-I-induced progesterone production. Both MAPK-Erk1/2 and MAPK-p38 participate in IGF-I-induced signaling pathways for progesterone production, while insulin-induced progesterone production requires MAPK-p38, but not MAPK-Erk1/2. These studies provide further evidence for divergence of insulin and IGF-I signaling pathways for human ovarian cell steroidogenesis.

  10. Surfactin inducing mitochondria-dependent ROS to activate MAPKs, NF-κB and inflammasomes in macrophages for adjuvant activity.

    PubMed

    Gan, Ping; Gao, Zhenqiu; Zhao, Xiuyun; Qi, Gaofu

    2016-12-14

    Surfactin, a natural lipopeptide, can be used both as parenteral and non-parenteral adjuvant for eliciting immune response. However, the mechanisms that confer its adjuvant properties have not been fully explored. By staining with NHS-Rhodamine B labeled surfactin and Mito-Tracker Green, we found surfactin could penetrate into macrophages to bind with mitochondria, following induce ROS that could be inhibited by mitochondria-dependent ROS inhibitor. ROS enhanced p38 MAPK and JNK expression, as well their phorsphorylation, following activated NF-κB nuclear translocation in macrophages that was obviously inhibited by mitochondria-dependent ROS inhibitor. However, inhibition of ROS production only weakened p38 MAPK and JNK expression, but not their phosphorylation in macrophages. As a result, surfaction could activate NF-κB to release TNF-α by the mitochondria-dependent ROS signalling pathway. ROS also induced macrophages apoptosis to release endogenous danger signals, following activated inflammasomes of NLRP1, NLRP3, IPAF and AIM2 in vitro and only NLRP1 in vivo, as well caspase-1 and IL-1 in macrophages, which were significantly inhibited by pre-treatment with ROS inhibitors. Collectively, surfactin as a kind of non-pathogen-associated molecular patterns, modulates host innate immunity by multiple signalling pathways, including induction of mitochondria-dependent ROS, activating MAPKs and NF-κB, and inducing cell apoptosis to realease endogenous danger signals for activation of inflammasomes.

  11. Surfactin inducing mitochondria-dependent ROS to activate MAPKs, NF-κB and inflammasomes in macrophages for adjuvant activity

    PubMed Central

    Gan, Ping; Gao, Zhenqiu; Zhao, Xiuyun; Qi, Gaofu

    2016-01-01

    Surfactin, a natural lipopeptide, can be used both as parenteral and non-parenteral adjuvant for eliciting immune response. However, the mechanisms that confer its adjuvant properties have not been fully explored. By staining with NHS-Rhodamine B labeled surfactin and Mito-Tracker Green, we found surfactin could penetrate into macrophages to bind with mitochondria, following induce ROS that could be inhibited by mitochondria-dependent ROS inhibitor. ROS enhanced p38 MAPK and JNK expression, as well their phorsphorylation, following activated NF-κB nuclear translocation in macrophages that was obviously inhibited by mitochondria-dependent ROS inhibitor. However, inhibition of ROS production only weakened p38 MAPK and JNK expression, but not their phosphorylation in macrophages. As a result, surfaction could activate NF-κB to release TNF-α by the mitochondria-dependent ROS signalling pathway. ROS also induced macrophages apoptosis to release endogenous danger signals, following activated inflammasomes of NLRP1, NLRP3, IPAF and AIM2 in vitro and only NLRP1 in vivo, as well caspase-1 and IL-1 in macrophages, which were significantly inhibited by pre-treatment with ROS inhibitors. Collectively, surfactin as a kind of non-pathogen-associated molecular patterns, modulates host innate immunity by multiple signalling pathways, including induction of mitochondria-dependent ROS, activating MAPKs and NF-κB, and inducing cell apoptosis to realease endogenous danger signals for activation of inflammasomes. PMID:27966632

  12. TNFα induces survival through the FLIP-L-dependent activation of the MAPK/ERK pathway

    PubMed Central

    Marques-Fernandez, F; Planells-Ferrer, L; Gozzelino, R; Galenkamp, K MO; Reix, S; Llecha-Cano, N; Lopez-Soriano, J; Yuste, V J; Moubarak, R S; Comella, J X

    2013-01-01

    Activation of tumor necrosis factor receptor-1 can trigger survival or apoptosis pathways. In many cellular models, including the neuronal cell model PC12, it has been demonstrated that inhibition of protein synthesis is sufficient to render cells sensitive to apoptosis induced by TNFα. The survival effect is linked to the translocation of the transcription factor nuclear factor-kappa B (NF-κB) to the nucleus and activation of survival-related genes such as FLICE-like inhibitory protein long form (FLIP-L) or IAPs. Nonetheless, we previously reported an NF-κB-independent contribution of Bcl-xL to cell survival after TNFα treatment. Here, we demonstrate that NF-κB-induced increase in FLIP-L expression levels is essential for mitogen-activated protein kinases/extracellular signal-regulated kinases (MAPK/ERK) activation. We demonstrate that FLIP-L behaves as a Raf-1 activator through both protein–protein interaction and Raf-1 kinase activation, without the requirement of the classical Ras activation. Importantly, prevention of FLIP-L increase by NF-κB inhibition or knockdown of endogenous FLIP-L blocks MAPK/ERK activation after TNFα treatment. From a functional point of view, we show that inhibition of the MAPK/ERK pathway and the NF-κB pathway are equally relevant to render PC12 cells sensitive to cell death induced by TNFα. Apoptosis induced by TNFα under these conditions is dependent on jun nuclear kinase1/2 JNK1/2-dependent Bim upregulation. Therefore, we report a previously undescribed and essential role for MAPK/ERK activation by FLIP-L in the decision between cell survival and apoptosis upon TNFα stimulation. PMID:23412386

  13. Sprouty 2: a novel attenuator of B-cell receptor and MAPK-Erk signaling in CLL.

    PubMed

    Shukla, Ashima; Rai, Karan; Shukla, Vipul; Chaturvedi, Nagendra K; Bociek, R Gregory; Pirruccello, Samuel J; Band, Hamid; Lu, Runqing; Joshi, Shantaram S

    2016-05-12

    Clinical heterogeneity is a major barrier to effective treatment of chronic lymphocytic leukemia (CLL). Emerging evidence suggests that constitutive activation of various signaling pathways like mitogen-activated protein kinase-extracellular signal-regulated kinase (MAPK-Erk) signaling plays a role in the heterogeneous clinical outcome of CLL patients. In this study, we have investigated the role of Sprouty (SPRY)2 as a negative regulator of receptor and nonreceptor tyrosine kinase signaling in the pathogenesis of CLL. We show that SPRY2 expression is significantly decreased in CLL cells, particularly from poor-prognosis patients compared with those from good-prognosis patients. Overexpression of SPRY2 in CLL cells from poor-prognosis patients increased their apoptosis. Conversely, downregulation of SPRY2 in CLL cells from good-prognosis patients resulted in increased proliferation. Furthermore, CLL cells with low SPRY2 expression grew more rapidly in a xenograft model of CLL. Strikingly, B-cell-specific transgenic overexpression of spry2 in mice led to a decrease in the frequency of B1 cells, the precursors of CLL cells in rodents. Mechanistically, we show that SPRY2 attenuates the B-cell receptor (BCR) and MAPK-Erk signaling by binding to and antagonizing the activities of RAF1, BRAF, and spleen tyrosine kinase (SYK) in normal B cells and CLL cells. We also show that SPRY2 is targeted by microRNA-21, which in turn leads to increased activity of Syk and Erk in CLL cells. Taken together, these results establish SPRY2 as a critical negative regulator of BCR-mediated MAPK-Erk signaling in CLL, thereby providing one of the molecular mechanisms to explain the clinical heterogeneity of CLL.

  14. A critical role for p38MAPK signalling pathway during reprogramming of human fibroblasts to iPSCs

    PubMed Central

    Neganova, Irina; Chichagova, Valeria; Armstrong, Lyle; Lako, Majlinda

    2017-01-01

    Reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) holds enormous promise for regenerative medicine. Reprogramming is a stepwise process with well-defined stages of initiation, maturation and stabilisation which are critically dependent on interactions between key pluripotency transcription factors, epigenetic regulators and signalling pathways. In this manuscript we have investigated the role of p38 MAPK signalling pathway and have shown a subpopulation- and phase-specific pattern of activation occurring during the initiation and maturation stage of reprogramming in partially and fully reprogrammed cells respectively. Downregulation of p38 MAPK activity via RNA interference or small molecule inhibitor led to cell accumulation in G1 phase of the cell cycle and reduced expression of cell cycle regulators during the initiation stage of reprogramming. This was associated with a significant downregulation of key pluripotency marker expression, disruption of mesenchymal to epithelial transition (MET), increased expression of differentiation markers and presence of partially reprogrammed cells which retained a typical gene expression profile of mesendodermal cells and were unable to progress to fully reprogrammed phenotype. Together our data indicate an important role for p38 MAPK activity in proliferation, MET progression and establishment of pluripotent phenotype, which are necessary steps for the development of human iPSCs. PMID:28155868

  15. 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

    SciTech Connect

    Kook, Sung-Ho; Lim, Shin-Saeng; Cho, Eui-Sic; Lee, Young-Hoon; Han, Seong-Kyu; Lee, Kyung-Yeol; Kwon, Jungkee; Hwang, Jae-Won; Bae, Cheol-Hyeon; Seo, Young-Kwon; Lee, Jeong-Chae

    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 potentials 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.

  16. Ozone (O{sub 3}) elicits neurotoxicity in spinal cord neurons (SCNs) by inducing ER Ca{sup 2+} release and activating the CaMKII/MAPK signaling pathway

    SciTech Connect

    Li, Yun; Lin, Xiaowen; Zhao, XueJun; Xie, Juntian; JunNan, Wang; Sun, Tao; Fu, Zhijian

    2014-11-01

    Ozone (O{sub 3}) is widely used in the treatment of spinal cord related diseases. Excess or accumulation of this photochemical air can however be neurotoxic. In this study, in vitro cultured Wister rat spinal cord neurons (SCNs) were used to investigate the detrimental effects and underlying mechanisms of O{sub 3}. Ozone in a dose-dependent manner inhibited cell viability at a range of 20 to 500 μg/ml, with the dose at 40 μg/ml resulting in a decrease of cell viability to 75%. The cell death after O{sub 3} exposure was related to endoplasmic reticulum (ER) calcium (Ca{sup 2+}) release. Intracellular Ca{sup 2+} chelator, ER stabilizer (inositol 1,4,5-trisphosphate receptor (IP3R) antagonist and ryanodine receptor (RyR) antagonist) and calcium/calmodulin-dependent protein kinase II (CaMKII) antagonist could effectively block Ca{sup 2+} mobilization and inhibit cell death following 40 μg/ml O{sub 3} exposure. In addition, ER Ca{sup 2+} release due to O{sub 3} exposure enhanced phospho-p38 and phospho-JNK levels and apoptosis of SCNs through activating CaMKII. Based on these results, we confirm that ozone elicits neurotoxicity in SCNs via inducing ER Ca{sup 2+} release and activating CaMKII/MAPK signaling pathway. Therefore, physicians should get attention to the selection of treatment concentrations of oxygen/ozone. And, approaches, such as chelating intracellular Ca{sup 2+} and stabilizing neuronal Ca{sup 2+} homeostasis could effectively ameliorate the neurotoxicity of O{sub 3}. - Highlights: • Exposure to O{sub 3} can reduce the viability of SCNs and cause the cell death. • Exposure to O{sub 3} can trigger RyR and IP3R dependent intracellular Ca{sup 2+} release. • Exposure to O{sub 3} can enhance the phospho-CaMKII, phospho-JNK and phospho-p38 levels.

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

    PubMed

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

    2015-09-01

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

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

    PubMed Central

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

    2015-01-01

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

  19. PUF-8 negatively regulates RAS/MAPK signalling to promote differentiation of C. elegans germ cells

    PubMed Central

    Vaid, Samir; Ariz, Mohd; Chaturbedi, Amaresh; Kumar, Ganga Anil; Subramaniam, Kuppuswamy

    2013-01-01

    Signals that promote germ cell self-renewal by preventing premature meiotic entry are well understood. However, signals that control mitotic proliferation to promote meiotic differentiation have not been well characterized. In Caenorhabditis elegans, GLP-1 Notch signalling promotes the proliferative fate by preventing premature meiotic entry. The germline niche cell, which is the source of the ligand for GLP-1, spatially restricts GLP-1 signalling and thus enables the germ cells that have moved away from the niche to enter meiosis. Here, we show that the suppression of RAS/MAP kinase signalling in the mitotic and meiotic-entry regions is essential for the regulation of the mitosis-meiosis switch by niche signalling. We provide evidence that the conserved PUF family RNA-binding protein PUF-8 and the RAS GAP protein GAP-3 function redundantly to suppress the LET-60 RAS in the mitotic and meiotic entry regions. Germ cells missing both PUF-8 and GAP-3 proliferate in an uncontrolled fashion and fail to undergo meiotic development. MPK-1, the MAP kinase downstream of the LET-60 RAS, is prematurely activated in these cells; downregulation of MPK-1 activation eliminates tumours and restores differentiation. Our results further reveal that PUF-8 negatively regulates LET-60 expression at a post-transcriptional step. LET-60 is misexpressed in the puf-8(-) mutant germlines and PUF-8 physically interacts with the let-60 3′ UTR. Furthermore, PUF-8 suppresses let-60 3′ UTR-mediated expression in the germ cells that are transitioning from the mitotic to meiotic fate. These results reveal that PUF-8-mediated inhibition of the RAS/MAPK pathway is essential for mitotic-to-meiotic fate transition. PMID:23487310

  20. Arabinosylated Lipoarabinomannan Skews Th2 Phenotype towards Th1 during Leishmania Infection by Chromatin Modification: Involvement of MAPK Signaling

    PubMed Central

    Bhattacharya, Parna; Gupta, Gaurav; Majumder, Saikat; Adhikari, Anupam; Banerjee, Sayantan; Halder, Kuntal; Bhattacharya Majumdar, Suchandra; Ghosh, Moumita; Chaudhuri, Shubho; Roy, Syamal; Majumdar, Subrata

    2011-01-01

    The parasitic protozoan Leishmania donovani is the causative organism for visceral leishmaniasis (VL) which persists in the host macrophages by deactivating its signaling machinery resulting in a critical shift from proinflammatory (Th1) to an anti-inflammatory (Th2) response. The severity of this disease is mainly determined by the production of IL-12 and IL-10 which could be reversed by use of effective immunoprophylactics. In this study we have evaluated the potential of Arabinosylated Lipoarabinomannan (Ara-LAM), a cell wall glycolipid isolated from non pathogenic Mycobacterium smegmatis, in regulating the host effector response via effective regulation of mitogen-activated protein kinases (MAPK) signaling cascades in Leishmania donovani infected macrophages isolated from BALB/C mice. Ara-LAM, a Toll-like receptor 2 (TLR2) specific ligand, was found to activate p38 MAPK signaling along with subsequent abrogation of extracellular signal–regulated kinase (ERKs) signaling. The use of pharmacological inhibitors of p38MAPK and ERK signaling showed the importance of these signaling pathways in the regulation of IL-10 and IL-12 in Ara-LAM pretreated parasitized macrophages. Molecular characterization of this regulation of IL-10 and IL-12 was revealed by chromatin immunoprecipitation assay (CHIP) which showed that in Ara-LAM pretreated parasitized murine macrophages there was a significant induction of IL-12 by selective phosphorylation and acetylation of histone H3 residues at its promoter region. While, IL-10 production was attenuated by Ara-LAM pretreatment via abrogation of histone H3 phosphorylation and acetylation at its promoter region. This Ara-LAM mediated antagonistic regulations in the induction of IL-10 and IL-12 genes were further correlated to changes in the transcriptional regulators Signal transducer and activator of transcription 3 (STAT3) and Suppressor of cytokine signaling 3 (SOCS3). These results demonstrate the crucial role played by Ara-LAM in

  1. Molecular basis of MAPK-activated protein kinase 2:p38 assembly

    PubMed Central

    White, Andre; Pargellis, Christopher A.; Studts, Joey M.; Werneburg, Brian G.; Farmer, Bennett T.

    2007-01-01

    p38 MAPK and MAPK-activated protein kinase 2 (MK2) are key components of signaling pathways leading to many cellular responses, notably the proinflammatory cytokine production. The physical association of p38α isoform and MK2 is believed to be physiologically important for this signaling. We report the 2.7-Å resolution crystal structure of the unphosphorylated complex between p38α and MK2. These protein kinases bind “head-to-head,” present their respective active sites on approximately the same side of the heterodimer, and form extensive intermolecular interactions. Among these interactions, the MK2 Ile-366–Ala-390, which includes the bipartite nuclear localization signal, binds to the p38α-docking region. This binding supports the involvement of noncatalytic regions to the tight binding of the MK2:p38α binary assembly. The MK2 residues 345–365, containing the nuclear export signal, block access to the p38α active site. Some regulatory phosphorylation regions of both protein kinases engage in multiple interactions with one another in this complex. This structure gives new insights into the regulation of the protein kinases p38α and MK2, aids in the better understanding of their known cellular and biochemical studies, and provides a basis for understanding other regulatory protein–protein interactions involving signal transduction proteins. PMID:17395714

  2. Differential effects of chronic overload-induced muscle hypertrophy on mTOR and MAPK signaling pathways in adult and aged rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined activation of the mammalian target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) signaling pathways in adult (Y; 6 mo old; n = 16) and aged (O; 30 mo old; n = 16) male rats (Fischer 344 x Brown Norway) subjected to chronic overload-induced muscle hypertrophy of the plan...

  3. Laminin-β1 impairs spatial learning through inhibition of ERK/MAPK and SGK1 signaling.

    PubMed

    Yang, Ying C; Ma, Yun L; Liu, Wen T; Lee, Eminy H Y

    2011-11-01

    Laminin is a major structural element of the basal lamina consisting of an α-chain, a β-chain, and a γ-chain arranged in a cross-like structure, with their C-terminal inter-coiled. Laminin is abundantly expressed in the hippocampus of mature brain and is implicated in several psychiatric disorders, but its possible role involved in learning and memory function is not known. This issue was examined here. Our results revealed that water maze training significantly decreased laminin-β1 (LB1) expression in the rat hippocampal CA1 area. Transfection of LB1 WT plasmid to hippocampal CA1 neurons impaired water maze performance in rats. Meanwhile, it decreased the phosphorylation level of ERK/MAPK and protein kinase serum- and glucocorticoid-inducible kinase-1 (SGK1). By contrast, knockdown of endogenous LB1 expression using RNA interference (LB1 siRNA) enhanced water maze performance. Meanwhile, it increased the phosphorylation level of ERK/MAPK and SGK1. The enhancing effect of LB1 siRNA on spatial learning and on the phosphorylation of ERK/MAPK and SGK1 was blocked by co-treatment with the MEK inhibitor U0126 at a concentration that did not apparently affect spatial learning and ERK/MAPK phosphorylation alone. Further, the enhancing effect of LB1 siRNA on spatial learning and SGK1 phosphorylation was similarly blocked by co-transfection with SGK1 siRNA at a concentration that did not markedly affect spatial learning and SGK1 expression alone. These results together indicate that LB1 negatively regulates spatial learning in rats. In addition, LB1 impairs spatial learning through decreased activation of the ERK/MAPK-SGK1 signaling pathway in the rat hippocampus.

  4. Regulation of Muscle Stem Cell Functions: A Focus on the p38 MAPK Signaling Pathway

    PubMed Central

    Segalés, Jessica; Perdiguero, Eusebio; Muñoz-Cánoves, Pura

    2016-01-01

    Formation of skeletal muscle fibers (myogenesis) during development and after tissue injury in the adult constitutes an excellent paradigm to investigate the mechanisms whereby environmental cues control gene expression programs in muscle stem cells (satellite cells) by acting on transcriptional and epigenetic effectors. Here we will review the molecular mechanisms implicated in the transition of satellite cells throughout the distinct myogenic stages (i.e., activation from quiescence, proliferation, differentiation, and self-renewal). We will also discuss recent findings on the causes underlying satellite cell functional decline with aging. In particular, our review will focus on the epigenetic changes underlying fate decisions and on how the p38 MAPK signaling pathway integrates the environmental signals at the chromatin to build up satellite cell adaptive responses during the process of muscle regeneration, and how these responses are altered in aging. A better comprehension of the signaling pathways connecting external and intrinsic factors will illuminate the path for improving muscle regeneration in the aged. PMID:27626031

  5. Parainfluenza Virus Type 1 Induces Epithelial IL-8 Production via p38-MAPK Signalling

    PubMed Central

    Galván Morales, Miguel Ángel; Cabello Gutiérrez, Carlos; Mejía Nepomuceno, Fidencio; Valle Peralta, Leticia; Valencia Maqueda, Elba; Manjarrez Zavala, María Eugenia

    2014-01-01

    Human parainfluenza virus type 1 (HPIV-1) is the most common cause of croup in infants. The aim of this study was to describe molecular mechanisms associated with IL-8 production during HPIV-1 infection and the role of viral replication in MAPK synthesis and activation. An in vitro model of HPIV-1 infection in the HEp-2 and A549 cell lines was used; a kinetic-based ELISA for IL-8 detection was also used, phosphorylation of the mitogen-activated protein kinases (MAPKs) was identified by Western blot analysis, and specific inhibitors for each kinase were used to identify which MAPK was involved. Inactivated viruses were used to assess whether viral replication is required for IL-8 production. Results revealed a gradual increase in IL-8 production at different selected times, when phosphorylation of MAPK was detected. The secretion of IL-8 in the two cell lines infected with the HPIV-1 is related to the phosphorylation of the MAPK as well as viral replication. Inhibition of p38 suppressed the secretion of IL-8 in the HEp-2 cells. No kinase activation was observed when viruses were inactivated. PMID:25013817

  6. Plakoglobin but not desmoplakin regulates keratinocyte cohesion via modulation of p38MAPK signaling.

    PubMed

    Spindler, Volker; Dehner, Carina; Hübner, Stefan; Waschke, Jens

    2014-06-01

    Plakoglobin (Pg) and desmoplakin (DP) are adapter proteins within the desmosome, providing a mechanical link between desmosomal cadherins as transmembrane adhesion molecules and the intermediate filament cytoskeleton. As in the severe skin blistering disease pemphigus, autoantibodies against desmosomal adhesion molecules induce loss of keratinocyte cohesion at least in part via p38 mitogen-activated protein kinase (p38MAPK) activation and depletion of desmosomal components, we evaluated the roles of Pg and DP in the p38MAPK-dependent loss of cell adhesion. Silencing of either Pg or DP reduced cohesion of cultured human keratinocytes in dissociation assays. However, Pg but not DP silencing caused activation of p38MAPK-dependent keratin filament collapse and cell dissociation. Interestingly, extranuclear but not nuclear Pg rescued loss of cell adhesion and keratin retraction. In line with this, Pg regulated the levels of the desmosomal adhesion molecule desmoglein 3 and tethered p38MAPK to desmosomal complexes. Our data demonstrate a role of extranuclear Pg in controlling cell adhesion via p38MAPK-dependent regulation of keratin filament organization.

  7. Scaffold mediated regulation of MAPK signaling and cytoskeletal dynamics: A perspective

    PubMed Central

    Pullikuth, Ashok K.; Catling, Andrew D.

    2008-01-01

    Cell migration is critical for many physiological processes and is often misregulated in developmental disorders and pathological conditions including cancer and neurodegeneration. MAPK signaling and the Rho family of proteins are known regulators of cell migration that exert their influence on cellular cytoskeleton during cell adhesion and migration. Here we review data supporting the view that localized ERK signaling mediated through recently identified scaffold proteins may regulate cell migration. PMID:17553668

  8. Data-Derived Modeling Characterizes Plasticity of MAPK Signaling in Melanoma

    PubMed Central

    Bernardo-Faura, Marti; Massen, Stefan; Falk, Christine S.; Brady, Nathan R.; Eils, Roland

    2014-01-01

    The majority of melanomas have been shown to harbor somatic mutations in the RAS-RAF-MEK-MAPK and PI3K-AKT pathways, which play a major role in regulation of proliferation and survival. The prevalence of these mutations makes these kinase signal transduction pathways an attractive target for cancer therapy. However, tumors have generally shown adaptive resistance to treatment. This adaptation is achieved in melanoma through its ability to undergo neovascularization, migration and rearrangement of signaling pathways. To understand the dynamic, nonlinear behavior of signaling pathways in cancer, several computational modeling approaches have been suggested. Most of those models require that the pathway topology remains constant over the entire observation period. However, changes in topology might underlie adaptive behavior to drug treatment. To study signaling rearrangements, here we present a new approach based on Fuzzy Logic (FL) that predicts changes in network architecture over time. This adaptive modeling approach was used to investigate pathway dynamics in a newly acquired experimental dataset describing total and phosphorylated protein signaling over four days in A375 melanoma cell line exposed to different kinase inhibitors. First, a generalized strategy was established to implement a parameter-reduced FL model encoding non-linear activity of a signaling network in response to perturbation. Next, a literature-based topology was generated and parameters of the FL model were derived from the full experimental dataset. Subsequently, the temporal evolution of model performance was evaluated by leaving time-defined data points out of training. Emerging discrepancies between model predictions and experimental data at specific time points allowed the characterization of potential network rearrangement. We demonstrate that this adaptive FL modeling approach helps to enhance our mechanistic understanding of the molecular plasticity of melanoma. PMID:25188314

  9. Involvement of PI3K and MAPK Signaling in bcl-2-induced Vascular Endothelial Growth Factor Expression in Melanoma Cells

    PubMed Central

    Trisciuoglio, Daniela; Iervolino, Angela; Zupi, Gabriella; Del Bufalo, Donatella

    2005-01-01

    We have previously demonstrated that bcl-2 overexpression in tumor cells exposed to hypoxia increases the expression of vascular endothelial growth factor (VEGF) gene through the hypoxia-inducible factor-1 (HIF-1). In this article, we demonstrate that exposure of bcl-2 overexpressing melanoma cells to hypoxia induced phosphorylation of AKT and extracellular signal-regulated kinase (ERK)1/2 proteins. On the contrary, no modulation of these pathways by bcl-2 was observed under normoxic conditions. When HIF-1α expression was reduced by RNA interference, AKT and ERK1/2 phosphorylation were still induced by bcl-2. Pharmacological inhibition of mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) signaling pathways reduced the induction of VEGF and HIF-1 in response to bcl-2 overexpression in hypoxia. No differences were observed between control and bcl-2-overexpressing cells in normoxia, in terms of VEGF protein secretion and in response to PI3K and MAPK inhibitors. We also demonstrated that RNA interference-mediated down-regulation of bcl-2 expression resulted in a decrease in the ERK1/2 phosphorylation and VEGF secretion only in bcl-2-overexpressing cell exposed to hypoxia but not in control cells. In conclusion, our results indicate, for the first time, that bcl-2 synergizes with hypoxia to promote expression of angiogenesis factors in melanoma cells through both PI3K- and MAPK-dependent pathways. PMID:15987743

  10. Transferrin receptor 2 and HFE regulate furin expression via mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/Erk) signaling. Implications for transferrin-dependent hepcidin regulation

    PubMed Central

    Poli, Maura; Luscieti, Sara; Gandini, Valentina; Maccarinelli, Federica; Finazzi, Dario; Silvestri, Laura; Roetto, Antonella; Arosio, Paolo

    2010-01-01

    Background Impaired regulation of hepcidin in response to iron is the cause of genetic hemochromatosis associated with defects of HFE and transferrin receptor 2. However, the role of these proteins in the regulation of hepcidin expression is unclear. Design and Methods Hepcidin expression, SMAD and extracellular signal-regulated kinase (Erk) phosphorylation and furin expression were analyzed in hepatic HepG2 cells in which HFE and transferrin receptor 2 were down-regulated or expressed, or furin activity specifically inhibited. Furin expression was also analyzed in the liver of transferrin receptor 2 null mice. Results We showed that the silencing of HFE and transferrin receptor 2 reduced both Erk phosphorylation and furin expression, that the exogenous expression of the two enhanced the induction of phosphoErk1/2 and furin by holotransferrin, but that this did not occur when the pathogenic HFE mutant C282Y was expressed. Furin, phosphoErk1/2 and phosphoSMAD1/5/8 were down-regulated also in transferrin receptor 2-null mice. Treatment of HepG2 cells with an inhibitor of furin activity caused a strong suppression of hepcidin mRNA, probably due to the inhibition of bone morphogenic protein maturation. Conclusions The data indicate that transferrin receptor 2 and HFE are involved in holotransferrin-dependent signaling for the regulation of furin which involved Erk phosphorylation. Furin in turn may control hepcidin expression. PMID:20634490

  11. Genome-wide gene expression profiling reveals aberrant MAPK and Wnt signaling pathways associated with early parthenogenesis.

    PubMed

    Liu, Na; Enkemann, Steven A; Liang, Ping; Hersmus, Remko; Zanazzi, Claudia; Huang, Junjiu; Wu, Chao; Chen, Zhisheng; Looijenga, Leendert H J; Keefe, David L; Liu, Lin

    2010-12-01

    Mammalian parthenogenesis could not survive but aborted during mid-gestation, presumably because of lack of paternal gene expression. To understand the molecular mechanisms underlying the failure of parthenogenesis at early stages of development, we performed global gene expression profiling and functional analysis of parthenogenetic blastocysts in comparison with those of blastocysts from normally fertilized embryos. Parthenogenetic blastocysts exhibited changes in the expression of 749 genes, of which 214 had lower expression and 535 showed higher expressions than fertilized embryos using a minimal 1.8-fold change as a cutoff. Genes important for placenta development were decreased in their expression in parthenote blastocysts. Some maternally expressed genes were up-regulated and paternal-related genes were down-regulated. Moreover, aberrantly increased Wnt signaling and reduced mitogen-activated protein kinase (MAPK) signaling were associated with early parthenogenesis. The protein level of extracellular signal-regulated kinase 2 (ERK2) was low in parthenogenetic blastocysts compared with that of fertilized blastocysts 120 h after fertilization. 6-Bromoindirubin-3'-oxime, a specific glycogen synthase kinase-3 (GSK-3) inhibitor, significantly decreased embryo hatching. The expression of several imprinted genes was altered in parthenote blastocysts. Gene expression also linked reduced expression of Xist to activation of X chromosome. Our findings suggest that failed X inactivation, aberrant imprinting, decreased ERK/MAPK signaling and possibly elevated Wnt signaling, and reduced expression of genes for placental development collectively may contribute to abnormal placenta formation and failed fetal development in parthenogenetic embryos.

  12. Insulin-independent, MAPK-dependent stimulation of NKCC activity in skeletal muscle.

    PubMed

    Wong, J A; Gosmanov, A R; Schneider, E G; Thomason, D B

    2001-08-01

    Na(+)-K(+)-Cl(-) cotransporter (NKCC) activity in quiescent skeletal muscle is modest. However, ex vivo stimulation of muscle for as little as 18 contractions (1 min, 0.3 Hz) dramatically increased the activity of the cotransporter, measured as the bumetanide-sensitive (86)Rb influx, in both soleus and plantaris muscles. This activation of cotransporter activity remained relatively constant for up to 10-Hz stimulation for 1 min, falling off at higher frequencies (30-Hz stimulation for 1 min). Similarly, stimulation of skeletal muscle with adrenergic receptor agonists phenylephrine, isoproterenol, or epinephrine produced a dramatic stimulation of NKCC activity. It did not appear that stimulation of NKCC activity was a reflection of increased Na(+)-K(+)-ATPase activity because insulin treatment did not stimulate NKCC activity, despite insulin's well-known stimulation of Na(+)-K(+)-ATPase activity. Stimulation of NKCC activity could be blocked by pretreatment with inhibitors of mitogen-activated protein kinase (MAPK) kinase 1/2 (MEK1/2) activity, indicating that activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) MAPKs may be required. These data indicate a regulated NKCC activity in skeletal muscle that may provide a significant pathway for potassium transport into skeletal muscle fibers.

  13. TGF-β1 contributes to CD8+ Treg induction through p38 MAPK signaling in ovarian cancer microenvironment.

    PubMed

    Wu, Meng; Chen, Xian; Lou, Jianfang; Zhang, Shuping; Zhang, Xiaojie; Huang, Lei; Sun, Ruihong; Huang, Peijun; Wang, Fang; Pan, Shiyang

    2016-07-12

    CD8+ regulatory T cells (Tregs) contribute to cancer progression and immune evasion. We previously reported that CD8+ Tregs could be induced in vitro by co-culture of CD8+ T cells with the OC cell lines SKOV3/A2780. Here, we described the role of TGF-β1 in CD8+ Treg induction by the OC microenvironment. OC patients expressed high levels of TGF-β1, as did the co-culture supernatant from CD8+ T cells and SKOV3. Additionally, TGF-β1 levels were positively correlated with CD8+ Treg percentages in OC. Neutralization experiments, cytokine studies and proliferation assays revealed that the in vitro-induced CD8+Tregs depended at least partially on up-regulated expression of TGF-β1 to exert their suppressive function. CD8+ T cells cultured with SKOV3 exhibited marked activation of p38 MAPK than CD8+ T cells cultured alone, which could be inhibited by TGF-β1-neutralizing antibody. Moreover, the p38 specific inhibitor SB203580 dose-dependently blocked the TGF-β1 activated conversion of CD8+ T cells into CD8+ Tregs. These data suggested that in vitro-induction of CD8+ Tregs depended in part on TGF-β1 activation of p38 MAPK signaling. Therefore, p38 MAPK could be a therapeutic target in OC anti-tumor immunotherapy.

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

    PubMed

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

    2016-08-24

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

  15. The PDZ Protein Canoe/AF-6 Links Ras-MAPK, Notch and Wingless/Wnt Signaling Pathways by Directly Interacting with Ras, Notch and Dishevelled

    PubMed Central

    Carmena, Ana; Speicher, Stephan; Baylies, Mary

    2006-01-01

    Over the past few years, it has become increasingly apparent that signal transduction pathways are not merely linear cascades; they are organized into complex signaling networks that require high levels of regulation to generate precise and unique cell responses. However, the underlying regulatory mechanisms by which signaling pathways cross-communicate remain poorly understood. Here we show that the Ras-binding protein Canoe (Cno)/AF-6, a PDZ protein normally associated with cellular junctions, is a key modulator of Wingless (Wg)/Wnt, Ras-Mitogen Activated Protein Kinase (MAPK) and Notch (N) signaling pathways cross-communication. Our data show a repressive effect of Cno/AF-6 on these three signaling pathways through physical interactions with Ras, N and the cytoplasmic protein Dishevelled (Dsh), a key Wg effector. We propose a model in which Cno, through those interactions, actively coordinates, at the membrane level, Ras-MAPK, N and Wg signaling pathways during progenitor specification. PMID:17183697

  16. Fasudil inhibits LPS-induced migration of retinal microglial cells via regulating p38-MAPK signaling pathway

    PubMed Central

    Xu, Fan; Xu, Yue; Zhu, Liqiong; Rao, Pinhong; Wen, Jiamin; Sang, Yunyun; Shang, Fu

    2016-01-01

    Purpose To investigate the effect and possible molecular mechanisms of fasudil on retinal microglial (RMG) cell migration. Methods Primary cultured RMG cells were incubated with lipopolysaccharide (LPS), fasudil, and/or SB203580 (a p38 inhibitor). RMG cell motility was determined with the scratch wound assay and the Transwell migration assay. The phosphorylation of p38 and levels of matrix metalloproteinase 2 (MMP-2) and MMP-9 were measured with western blot. Results In the scratch-induced migration assay, as well as in the Transwell migration assay, the results indicated that LPS stimulated the migratory potential of RMG cells and fasudil significantly reduced LPS-stimulated RMG cell migration in a concentration-dependent manner. However, fasudil had no effect on RMG cell migration in the absence of LPS stimulation. Moreover, fasudil reduced the level of phosphor-p38 mitogen-activated protein kinase (p-p38-MAPK) in a concentration-dependent manner, without effects on the levels of phospho-p44/42 (p-ERK1/2) and phospho-c-Jun N-terminal kinase (p-JNK). Cotreatment with SB203580 (a p38 inhibitor) and fasudil resulted in the synergistic reduction of MMP-2, MMP-9, and p-p38-MAPK, as well as a reduction in the LPS-stimulated migration capabilities of the RMG cells, suggesting fasudil suppresses the LPS-stimulated migration of RMG cells via directly downregulating the p38-MAPK signaling pathway. Conclusions Our studies indicated that fasudil inhibited LPS-stimulated RMG cell migration via suppression of the p38-MAPK signaling pathway. PMID:27441000

  17. Prunetin signals via G-protein-coupled receptor, GPR30(GPER1): Stimulation of adenylyl cyclase and cAMP-mediated activation of MAPK signaling induces Runx2 expression in osteoblasts to promote bone regeneration.

    PubMed

    Khan, Kainat; Pal, Subhashis; Yadav, Manisha; Maurya, Rakesh; Trivedi, Arun Kumar; Sanyal, Sabyasachi; Chattopadhyay, Naibedya

    2015-12-01

    Prunetin is found in red clover and fruit of Prunus avium (red cherry). The effect of prunetin on osteoblast function, its mode of action and bone regeneration in vivo were investigated. Cultures of primary osteoblasts, osteoblastic cell line and HEK293T cells were used for various in vitro studies. Adult female rats received drill-hole injury at the femur diaphysis to assess the bone regenerative effect of prunetin. Prunetin at 10nM significantly (a) increased proliferation and differentiation of primary cultures of osteoblasts harvested from rats and (b) promoted formation of mineralized nodules by bone marrow stromal/osteoprogenitor cells. At this concentration, prunetin did not activate any of the two nuclear estrogen receptors (α and β). However, prunetin triggered signaling via a G-protein-coupled receptor, GPR30/GPER1, and enhanced cAMP levels in osteoblasts. G15, a selective GPR30 antagonist, abolished prunetin-induced increases in osteoblast proliferation, differentiation and intracellular cAMP. In osteoblasts, prunetin up-regulated runt-related transcription factor 2 (Runx2) protein through cAMP-dependent Erk/MAP kinase activation that ultimately resulted in the up-regulation of GPR30. Administration of prunetin at 0.25mg/kg given to rats stimulated bone regeneration at the site of drill hole and up-regulated Runx2 expression in the fractured callus and the effect was comparable to human parathyroid hormone, the only clinically used osteogenic therapy. We conclude that prunetin promotes osteoinduction in vivo and the mechanism is defined by signaling through GPR30 resulting in the up-regulation of the key osteogenic gene Runx2 that in turn up-regulates GPR30.

  18. Ghrelin Protects against Dexamethasone-Induced INS-1 Cell Apoptosis via ERK and p38MAPK Signaling

    PubMed Central

    2016-01-01

    Glucocorticoid excess induces apoptosis of islet cells, which may result in diabetes. In this study, we investigated the protective effect of ghrelin on dexamethasone-induced INS-1 cell apoptosis. Our data showed that ghrelin (0.1 μM) inhibited dexamethasone-induced (0.1 μM) apoptosis of INS-1 cells and facilitated cell proliferation. Moreover, ghrelin upregulated Bcl-2 expression, downregulated Bax expression, and decreased caspase-3 activity. The protective effect of ghrelin against dexamethasone-induced INS-1 cell apoptosis was mediated via growth hormone secretagogue receptor 1a. Further studies revealed that ghrelin increased ERK activation and decreased p38MAPK expression after dexamethasone treatment. Ghrelin-mediated protection of dexamethasone-induced apoptosis of INS-1 cells was attenuated using the ERK inhibitor U0126 (10 μM), and cell viability increased using the p38MAPK inhibitor SB203580 (10 μM). In conclusion, ghrelin could protect against dexamethasone-induced INS-1 cell apoptosis, at least partially via GHS-R1a and the signaling pathway of ERK and p38MAPK. PMID:27190513

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

    PubMed Central

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

    2012-01-01

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

  20. 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.

  1. Heme Oxygenase-1 Regulates Dendritic Cell Function through Modulation of p38 MAPK-CREB/ATF1 Signaling*

    PubMed Central

    Al-Huseini, Laith M. A.; Aw Yeang, Han Xian; Hamdam, Junnat M.; Sethu, Swaminathan; Alhumeed, Naif; Wong, Wai; Sathish, Jean G.

    2014-01-01

    Dendritic cells (DCs) are critical for the initiation of immune responses including activation of CD8 T cells. Intracellular reactive oxygen species (ROS) levels influence DC maturation and function. Intracellular heme, a product of catabolism of heme-containing metalloproteins, is a key inducer of ROS. Intracellular heme levels are regulated by heme oxygenase-1 (HO-1), which catalyzes the degradation of heme. Heme oxygenase-1 has been implicated in regulating DC maturation; however, its role in other DC functions is unclear. Furthermore, the signaling pathways modulated by HO-1 in DCs are unknown. In this study, we demonstrate that inhibition of HO-1 activity in murine bone marrow-derived immature DCs (iDCs) resulted in DCs with raised intracellular ROS levels, a mature phenotype, impaired phagocytic and endocytic function, and increased capacity to stimulate antigen-specific CD8 T cells. Interestingly, our results reveal that the increased ROS levels following HO-1 inhibition did not underlie the changes in phenotype and functions observed in these iDCs. Importantly, we show that the p38 mitogen-activated protein kinase (p38 MAPK), cAMP-responsive element binding protein (CREB), and activating transcription factor 1 (ATF1) pathway is involved in the mediation of the phenotypic and functional changes arising from HO-1 inhibition. Furthermore, up-regulation of HO-1 activity rendered iDCs refractory to lipopolysaccharide-induced activation of p38 MAPK-CREB/ATF1 pathway and DC maturation. Finally, we demonstrate that treatment of iDC with the HO-1 substrate, heme, recapitulates the effects that result from HO-1 inhibition. Based on these results, we conclude that HO-1 regulates DC maturation and function by modulating the p38 MAPK-CREB/ATF1 signaling axis. PMID:24719331

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

    SciTech Connect

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

    2014-07-18

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

  3. Integrin binding and MAPK signal pathways in primary cell responses to surface chemistry of calcium silicate cements.

    PubMed

    Shie, Ming-You; Ding, Shinn-Jyh

    2013-09-01

    Cell attachment, proliferation and differentiation on different materials depend largely on the surface properties of the materials. This study sheds light on the mechanism by which the modulation of the chemical composition of calcium silicate cements with different Si/Ca molar ratios could produce different cell responses. Two primary cell types (human mesenchymal stem cells (hMSCs) and human dental pulp cells (hDPCs)) were used to elicit the changes in total DNA content, integrin subunit levels, phosphor-focal adhesion kinase (pFAK) levels, and mitogen-activated protein kinase (MAPK) signaling pathway activity at the cell attachment stage. The effect of small interfering RNA (siRNA) transfection targeting collagen type I (COL I) and fibronectin (FN) was also evaluated. The results indicated that increased total DNA content, pFAK and total integrin levels were observed upon an increase in cement Si content. Cements with different Si/Ca ratios did not cause the variations of interleukin 1β (IL-1β), epidermal growth factor (EGF) and tumor necrosis factor-α (TNF-α) ligands. The Si-rich cement facilitated COL I and α2β1 subintegrin expression, while Ca-rich cement promoted FN and αvβ3 subintegrin expression. Si component of the calcium silicates stimulated cell adhesion via activation of MAPK/extracellular signal-regulated kinase (ERK) and p38 signaling pathways more effectively than did by Ca component, but it did not affect c-Jun NH2-terminal kinase (JNK) activity. Inhibition of MAPK/ERK and MAPK/p38 signaling pathways in hMSCs and hDPCs significantly attenuated adhesion, proliferation and differentiation as assessed according to total DNA content and alkaline phosphatase activity. hMSCs and hDPCs from the three different donors exhibited a similar preference for cell behaviors. The results of the current study suggest that calcium silicate cements with a higher Si content have the potential to serve as excellent supports for primary cells. Unraveling the

  4. Both mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinases (ERK) 1/2 and phosphatidylinositide-3-OH kinase (PI3K)/Akt pathways regulate activation of E-twenty-six (ETS)-like transcription factor 1 (Elk-1) in U138 glioblastoma cells.

    PubMed

    Mut, Melike; Lule, Sevda; Demir, Ozlem; Kurnaz, Isil Aksan; Vural, Imran

    2012-02-01

    Epidermal growth factor (EGF) and its receptor (EGFR) have been shown to play a significant role in the pathogenesis of glioblastoma. In our study, the EGFR was stimulated with EGF in human U138 glioblastoma cells. We show that the activated mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinases (ERK) 1/2 pathway phosphorylated the E twenty-six (ETS)-like transcription factor 1 (Elk-1) mainly at serine 383 residue. Mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, UO126 and ERK inhibitor II, FR180204 blocked the Elk-1 phosphorylation and activation. The phosphatidylinositide-3-OH kinase (PI3K)/Akt pathway was also involved in the Elk-1 activation. Activation of the Elk-1 led to an increased survival and a proliferative response with the EGF stimulation in the U138 glioblastoma cells. Knocking-down the Elk-1 using an RNA interference technique caused a decrease in survival of the unstimulated U138 glioblastoma cells and also decreased the proliferative response to the EGF stimulation. The Elk-1 transcription factor was important for the survival and proliferation of U138 glioblastoma cells upon the stimulation of EGFR with EGF. The MAPK/ERK1/2 and PI3K/Akt pathways regulated this response via activation of the Elk-1 transcription factor. The Elk-1 may be one of the convergence points for pathways located downstream of EGFR in glioblastoma cells. Utilization of the Elk-1 as a therapeutic target may lead to a novel strategy in treatment of glioblastoma.

  5. Overexpression of the MAP kinase gene OsMAPK33 enhances sensitivity to salt stress in rice (Oryza sativa L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mitogen-activated protein kinases (MAPK) signaling cascades are activated by extracellular stimuli such as environmental stresses and pathogens in higher eukaryotic plants. To know more about MAPK signaling in plants, a MAPK cDNA clone, OsMAPK33 was isolated from rice. The gene is mainly induced by ...

  6. TGF-β/MAPK signaling mediates the effects of bone marrow mesenchymal stem cells on urinary control and interstitial cystitis after urinary bladder transplantation

    PubMed Central

    Xiao, Ya; Song, Ya-Jun; Song, Bo; Huang, Chi-Bing; Ling, Qing; Yu, Xiao

    2017-01-01

    Objective: This study aimed to explore the role of the transforming growth factor-β/mitogen activated protein kinase (TGF-β/MAPK) signaling pathway in the effects of bone marrow mesenchymal stem cells (BMSCs) on urinary control and interstitial cystitis in a rat model of urinary bladder transplantation. Methods: A urinary bladder transplantation model was established using Sprague-Dawley rats. Rats were assigned to normal (blank control), negative control (phosphate-buffered saline injection), BMSCs (BMSC injection), sp600125 (MAPK inhibitor injection), or protamine sulfate (protamine sulfate injection) groups. Immunohistochemistry, urodynamic testing, hematoxylin-eosin staining, Western blotting, enzyme-linked immunosorbent assay, and MTT assay were used to assess BMSC growth, the kinetics of bladder urinary excretion, pathological changes in bladder tissue, bladder tissue ultrastructure, the expression of TGF-β/MAPK signaling pathway-related proteins, levels of inflammatory cytokines, and the effects of antiproliferative factor on cell proliferation. Results: Compared with normal, negative control, BMSCs, and sp600125 groups, rats in the PS group exhibited decreased discharge volume, maximal micturition volume, contraction interval, and bladder capacity but increased residual urine volume, bladder pressure, bladder peak pressure, expression of TGF-β/MAPK signaling pathway-related proteins, levels of inflammatory cytokines, and growth inhibition rate. Levels of inflammatory cytokines and the growth inhibition rate were positively correlated with the expression of TGF-β/MAPK signaling pathway-related proteins. Conclusions: Our findings demonstrate that the TGF-β/MAPK signaling pathway mediates the beneficial effects of BMSCs on urinary control and interstitial cystitis. PMID:28386345

  7. Rutin Protects against Pirarubicin-Induced Cardiotoxicity through TGF-β1-p38 MAPK Signaling Pathway

    PubMed Central

    Wang, Yadi; Zhang, Yang; Sun, Bo; Tong, Qing

    2017-01-01

    We investigated the potential protective effect of rutinum (RUT) against pirarubicin- (THP-) induced cardiotoxicity. THP was used to induce toxicity in rat H9c2 cardiomyoblasts. Positive control cells were pretreated with a cardioprotective agent dexrazoxane (DZR) prior to treatment with THP. Some of the cells were preincubated with RUT and a p38 mitogen-activated protein kinase (MAPK) inhibitor, SB203580, both individually and in combination, prior to THP exposure. At a dose range of 30–70 μM, RUT significantly prevented THP-induced reduction in cell viability; the best cardioprotective effect was observed at a dose of 50 μM. Administration of RUT and SB203580, both individually as well as in combination, suppressed the elevation of intracellular ROS, inhibited cell apoptosis, and reversed the THP-induced upregulation of TGF-β1, p-p38 MAPK, cleaved Caspase-9, Caspase-7, and Caspase-3. A synergistic effect was observed on coadministration of RUT and SB203580. RUT protected against THP-induced cardiotoxicity by inhibition of ROS generation and suppression of cell apoptosis. The cardioprotective effect of RUT appears to be associated with the modulation of the TGF-β1-p38 MAPK signaling pathway. PMID:28367221

  8. Lonchocarpine Increases Nrf2/ARE-Mediated Antioxidant Enzyme Expression by Modulating AMPK and MAPK Signaling in Brain Astrocytes

    PubMed Central

    Jeong, Yeon-Hui; Park, Jin-Sun; Kim, Dong-Hyun; Kim, Hee-Sun

    2016-01-01

    Lonchocarpine is a phenylpropanoid compound isolated from Abrus precatorius that has anti-bacterial, anti-inflammatory, antiproliferative, and antiepileptic activities. In the present study, we investigated the antioxidant effects of lonchocarpine in brain glial cells and analyzed its molecular mechanisms. We found that lonchocarpine suppressed reactive oxygen species (ROS) production and cell death in hydrogen peroxide-treated primary astrocytes. In addition, lonchocarpine increased the expression of antioxidant enzymes, such as heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO1), and manganese superoxide dismutase (MnSOD), which are all under the control of Nrf2/antioxidant response element (ARE) signaling. Further, mechanistic studies showed that lonchocarpine increases the nuclear translocation and DNA binding of Nrf2 to ARE as well as ARE-mediated transcriptional activities. Moreover, lonchocarpine increased the phosphorylation of AMP-activated protein kinase (AMPK) and three types of mitogen-activated protein kinases (MAPKs). By treating astrocytes with each signaling pathway-specific inhibitor, AMPK, c-jun N-terminal protein kinase (JNK), and p38 MAPK were identified to be involved in lonchocarpine-induced HO-1 expression and ARE-mediated transcriptional activities. Therefore, lonchocarpine may be a potential therapeutic agent for neurodegenerative diseases that are associated with oxidative stress. PMID:27737527

  9. Aurora kinase A interacts with H-Ras and potentiates Ras-MAPK signaling | Office of Cancer Genomics

    Cancer.gov

    In cancer, upregulated Ras promotes cellular transformation and proliferation in part through activation of oncogenic Ras-MAPK signaling. While directly inhibiting Ras has proven challenging, new insights into Ras regulation through protein-protein interactions may offer unique opportunities for therapeutic intervention. Here we report the identification and validation of Aurora kinase A (Aurora A) as a novel Ras binding protein. We demonstrate that the kinase domain of Aurora A mediates the interaction with the N-terminal domain of H-Ras.

  10. The role of MAPK signaling pathway in the Her-2-positive meningiomas

    PubMed Central

    Wang, Zhaoyin; Wang, Weijia; Xu, Shan; Wang, Shanshan; Tu, Yi; Xiong, Yifeng; Mei, Jinhong; Wang, Chunliang

    2016-01-01

    Meningiomas are common types of adult nerve system tumors. Although most cases are considered benign, due to its high rate of recurrence and easy malignant progression to anaplastic meningioma they present a puzzle for the current treatment. The HER-2 oncogene has important value for meningioma cells development and progression. So far, little is known about the effect on the exact underlying signal pathway and molecular mechanisms of HER-2-positive meningioma cells. The goal of the present study was to determine the effects of HER-2 gene and possible involvement of MAPK signal pathway in human malignant meningioma. We applied q-PCR analysis, immunofluorescence (IF) staining, western blot analysis, animal model, MAPK inhibition, MTT assay and cell invasion analysis for the investigation. The results demonstrated that the downregulation of the expression of HER-2 significantly inhibited cell motility and proliferation of human meningioma cells in vivo. Accordingly, in the HER-2-overexpression meningioma cells with the inhibition of ERK1/2, ERK5, JNK, in the cells with the ERK1/2, ERK5 inhibition, protein expression was markedly suppressed as well as the cell proliferation resistance. No difference was observed in the HER-2-overexpression meningioma cells with the inhibition of JNK. These findings suggest that HER-2 gene can affect the proliferation ability of human meningioma cells in vivo and MAPK signal pathway may contribute to the carcinogenesis and development of human meningiomas combinating with HER-2. PMID:27279438

  11. Spatial focalization of pheromone/MAPK signaling triggers commitment to cell-cell fusion.

    PubMed

    Dudin, Omaya; Merlini, Laura; Martin, Sophie G

    2016-10-01

    Cell fusion is universal in eukaryotes for fertilization and development, but what signals this process is unknown. Here, we show in Schizosaccharomyces pombe that fusion does not require a dedicated signal but is triggered by spatial focalization of the same pheromone-GPCR (G-protein-coupled receptor)-MAPK signaling cascade that drives earlier mating events. Autocrine cells expressing the receptor for their own pheromone trigger fusion attempts independently of cell-cell contact by concentrating pheromone release at the fusion focus, a dynamic actin aster underlying the secretion of cell wall hydrolases. Pheromone receptor and MAPK cascade are similarly enriched at the fusion focus, concomitant with fusion commitment in wild-type mating pairs. This focalization promotes cell fusion by immobilizing the fusion focus, thus driving local cell wall dissolution. We propose that fusion commitment is imposed by a local increase in MAPK concentration at the fusion focus, driven by a positive feedback between fusion focus formation and focalization of pheromone release and perception.

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

    SciTech Connect

    Dziembowska, Magdalena; Danilkiewicz, Malgorzata; Wesolowska, Aleksandra; Zupanska, Agata; Chouaib, Salem; Kaminska, Bozena . E-mail: bozenakk@nencki.gov.pl

    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: ATF2 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.

  13. SB203580 Modulates p38 MAPK Signaling and Dengue Virus-Induced Liver Injury by Reducing MAPKAPK2, HSP27, and ATF2 Phosphorylation

    PubMed Central

    Sreekanth, Gopinathan Pillai; Chuncharunee, Aporn; Sirimontaporn, Aunchalee; Panaampon, Jutatip; Noisakran, Sansanee; Yenchitsomanus, Pa-thai; Limjindaporn, Thawornchai

    2016-01-01

    Dengue virus (DENV) infection causes organ injuries, and the liver is one of the most important sites of DENV infection, where viral replication generates a high viral load. The molecular mechanism of DENV-induced liver injury is still under investigation. The mitogen activated protein kinases (MAPKs), including p38 MAPK, have roles in the hepatic cell apoptosis induced by DENV. However, the in vivo role of p38 MAPK in DENV-induced liver injury is not fully understood. In this study, we investigated the role of SB203580, a p38 MAPK inhibitor, in a mouse model of DENV infection. Both the hematological parameters, leucopenia and thrombocytopenia, were improved by SB203580 treatment and liver transaminases and histopathology were also improved. We used a real-time PCR microarray to profile the expression of apoptosis-related genes. Tumor necrosis factor α, caspase 9, caspase 8, and caspase 3 proteins were significantly lower in the SB203580-treated DENV-infected mice than that in the infected control mice. Increased expressions of cytokines including TNF-α, IL-6 and IL-10, and chemokines including RANTES and IP-10 in DENV infection were reduced by SB203580 treatment. DENV infection induced the phosphorylation of p38MAPK, and its downstream signals including MAPKAPK2, HSP27 and ATF-2. SB203580 treatment did not decrease the phosphorylation of p38 MAPK, but it significantly reduced the phosphorylation of MAPKAPK2, HSP27, and ATF2. Therefore, SB203580 modulates the downstream signals to p38 MAPK and reduces DENV-induced liver injury. PMID:26901653

  14. A sestrin-dependent Erk-Jnk-p38 MAPK activation complex inhibits immunity during aging.

    PubMed

    Lanna, Alessio; Gomes, Daniel C O; Muller-Durovic, Bojana; McDonnell, Thomas; Escors, David; Gilroy, Derek W; Lee, Jun Hee; Karin, Michael; Akbar, Arne N

    2017-03-01

    Mitogen-activated protein kinases (MAPKs) including Erk, Jnk and p38 regulate diverse cellular functions and are thought to be controlled by independent upstream activation cascades. Here we show that the sestrins bind to and coordinate simultaneous Erk, Jnk and p38 MAPK activation in T lymphocytes within a new immune-inhibitory complex (sestrin-MAPK activation complex (sMAC)). Whereas sestrin ablation resulted in broad reconstitution of immune function in stressed T cells, inhibition of individual MAPKs allowed only partial functional recovery. T cells from old humans (>65 years old) or mice (16-20 months old) were more likely to form the sMAC, and disruption of this complex restored antigen-specific functional responses in these cells. Correspondingly, sestrin deficiency or simultaneous inhibition of all three MAPKs enhanced vaccine responsiveness in old mice. Thus, disruption of sMAC provides a foundation for rejuvenating immunity during aging.

  15. Defective angiogenesis, endothelial migration, proliferation, and MAPK signaling in Rap1b-deficient mice

    PubMed Central

    Kraus, Anna E.; Gale, Daniel; White, Gilbert C.; VanSluys, Jillian

    2008-01-01

    Angiogenesis is the main mechanism of vascular remodeling during late development and, after birth, in wound healing. Perturbations of angiogenesis occur in cancer, diabetes, ischemia, and inflammation. While much progress has been made in identifying factors that control angiogenesis, the understanding of the precise molecular mechanisms involved is incomplete. Here we identify a small GTPase, Rap1b, as a positive regulator of angiogenesis. Rap1b-deficient mice had a decreased level of Matrigel plug and neonatal retinal neovascularization, and aortas isolated from Rap1b-deficient animals had a reduced microvessel sprouting response to 2 major physiological regulators of angiogenesis: vascular endothelial growth factor (VEGF) and basic fibroblasts growth factor (bFGF), indicating an intrinsic defect in endothelial cells. Proliferation of retinal endothelial cells in situ and in vitro migration of lung endothelial cells isolated from Rap1b-deficient mice were inhibited. At the molecular level, activation of 2 MAP kinases, p38 MAPK and p42/44 ERK, important regulators of endothelial migration and proliferation, was decreased in Rap1b-deficient endothelial cells in response to VEGF stimulation. These studies provide evidence that Rap1b is required for normal angiogenesis and reveal a novel role of Rap1 in regulation of proangiogenic signaling in endothelial cells. PMID:17993608

  16. Identification, nomenclature, and evolutionary relationships of mitogen-activated protein kinase (MAPK) genes in soybean.

    PubMed

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

    2013-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  18. Cu2+ and acute thermal stress induce protective events via the p38-MAPK signalling pathway in the perfused Rana ridibunda heart.

    PubMed

    Gaitanaki, Catherine; Pliatska, Maria; Stathopoulou, Konstantina; Beis, Isidoros

    2007-02-01

    In the present study, we investigated the induction of the p38-MAPK signalling pathway by copper, as exemplified by CuCl(2), in the isolated perfused heart of the amphibian Rana ridibunda. We found that p38-MAPK phosphorylation by CuCl(2) occurs in a dose-dependent manner, with maximum activation (8.73+/-1.43-fold relative to control values) attained by perfusion with 500 micromol l(-1) CuCl(2) for 15 min, while this activation sustained even after 60 min of reperfusion with normal bicarbonate buffer. CuCl(2) also induced the phosphorylation of the small heat shock protein 27 (Hsp27) in a p38-MAPK dependent manner, as revealed by experiments using the p38-MAPK inhibitor SB203580. p38-MAPK and Hsp27 phosphorylations were also strongly induced by hyperthermia (42 degrees C), while the simultaneous use of hyperthermia and CuCl(2) had a synergistic effect on p38-MAPK activation. Furthermore, perfusions with the potent antioxidant L-ascorbic acid (100 micromol l(-1)), the antioxidant enzymes catalase (CAT) (150 U ml(-1)) or superoxide dismutase (SOD) (30 U ml(-1)) in the presence of 500 micromol l(-1) CuCl(2) did not attenuate the CuCl(2)-induced p38-MAPK activation, implying that at least the reactive oxygen species (ROS) scavenged by these agents are not implicated in this kinase activation. The p38-MAPK phosphorylation induced by the combined action of CuCl(2) and hyperthermia was partially inhibited by catalase, indicating that hyperthermia possibly activates the kinase through the production of H(2)O(2). Caspase-3, an effector protease of apoptosis, remained inactive in hearts perfused at normal or hyperthermic conditions, in the absence or presence of 500 micromol l(-1) CuCl(2). All the above results suggest that, in the amphibian Rana ridibunda heart, p38-MAPK activation by copper has a possible protective role through the small Hsp27.

  19. Alterations in left ventricular function during intermittent hypoxia: Possible involvement of O-GlcNAc protein and MAPK signaling.

    PubMed

    Guo, Xueling; Shang, Jin; Deng, Yan; Yuan, Xiao; Zhu, Die; Liu, Huiguo

    2015-07-01

    Obstructive sleep apnea, characterized by recurrent episodes of hypoxia [intermittent hypoxia (IH)], has been identified as a risk factor for cardiovascular diseases. The O-linked β-N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation) of proteins has important regulatory implications on the pathophysiology of cardiovascular disorders. In this study, we examined the role of O-GlcNAcylation in cardiac architecture and left ventricular function following IH. Rats were randomly assigned to a normoxia and IH group (2 min 21% O2; 2 min 6-8% O2). Left ventricular function, myocardial morphology and the levels of signaling molecules were then measured. IH induced a significant increase in blood pressure, associated with a gradually abnormal myocardial architecture. The rats exposed to 2 or 3 weeks of IH presented with augmented left ventricular systolic and diastolic function, which declined at week 4. Consistently, the O-GlcNAc protein and O-GlcNAcase (OGA) levels in the left ventricular tissues steadily increased following IH, reaching peak levels at week 3. The O-GlcNAc transferase (OGT), extracellular signal-regulated kinase 1/2 (ERK1/2) and the p38 mitogen-activated protein kinase (p38 MAPK) phosphorylation levels were affected in an opposite manner. The phosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII) remained unaltered. In parallel, compared with exposure to normoxia, 4 weeks of IH augmented the O-GlcNAc protein, OGT, phosphorylated ERK1/2 and p38 MAPK levels, accompanied by a decrease in OGA levels and an increase in the levels of myocardial nuclear factor-κB (NF-κB), inflammatory cytokines, caspase-3 and cardiomyocyte apoptosis. Taken together, our suggest a possible involvement of O-GlcNAc protein and MAPK signaling in the alterations of left ventricular function and cardiac injury following IH.

  20. Role of protein kinase C in TBT-induced inhibition of lytic function and MAPK activation in human natural killer cells.

    PubMed

    Abraha, Abraham B; Rana, Krupa; Whalen, Margaret M

    2010-11-01

    Human natural killer (NK) cells are lymphocytes that destroy tumor and virally infected cells. Previous studies have shown that exposure of NK cells to tributyltin (TBT) greatly diminishes their ability to destroy tumor cells (lytic function) while activating mitogen-activated protein kinases (MAPK) (p44/42, p38, and JNK) in NK cells. The signaling pathway that regulates NK lytic function appears to include activation of protein kinase C(PKC) as well as MAPK activity. TBT-induced activation of MAPKs would trigger a portion of the NK lytic signaling pathway, which would then leave the NK cell unable to trigger this pathway in response to a subsequent encounter with a target cell. In the present study we evaluated the involvement of PKC in inhibition of NK lysis of tumor cells and activation of MAPKs caused by TBT exposure. TBT caused a 2–3-fold activation of PKC at concentrations ranging from 50 to 300 nM (16–98 ng/ml),indicating that activation of PKC occurs in response to TBT exposure. This would then leave the NK cell unable to respond to targets. Treatment with the PKC inhibitor, bisindolylmaleimide I, caused an 85% decrease in the ability of NK cells to lyse tumor cells, validating the involvement of PKC in the lytic signaling pathway. The role of PKC in the activation of MAPKs by TBT was also investigated using bisindolylmaleimide I. The results indicated that, in NK cells where PKC activation was blocked, there was no activation of the MAPK, p44/42 in response to TBT.However, TBT-induced activation of the MAPKs, p38 and JNK did not require PKC activation. These results indicate the pivotal role of PKC in the TBT-induced loss of NK lytic function including activation of p44/42 by TBT in NK cells.

  1. Chicoric acid induces apoptosis in 3T3-L1 preadipocytes through ROS-mediated PI3K/Akt and MAPK signaling pathways.

    PubMed

    Xiao, Haifang; Wang, Jing; Yuan, Li; Xiao, Chunxia; Wang, Yutang; Liu, Xuebo

    2013-02-20

    Chicoric acid has been reported to possess various bioactivities. However, the antiobesity effects of chicoric acid remain poorly understood. In this study, we investigated the effects of chicoric acid on 3T3-L1 preadipocytes and its molecular mechanisms of apoptosis. Chicoric acid inhibited cell viability and induced apoptosis in 3T3-L1 preadipocytes which was characterized by chromatin condensation and poly ADP-ribose-polymerase (PARP) cleavage. Mitochondrial membrane potential (MMP) loss, Bax/Bcl-2 dysregulation, cytochrome c release, and caspase-3 activation were observed, indicating mitochondria-dependent apoptosis induced by chicoric acid. Furthermore, PI3K/Akt and MAPK (p38 MAPK, JNK, and ERK1/2) signaling pathways were involved in chicoric acid-induced apoptosis. The employment of protein kinase inhibitors LY294002, SB203580, SP600125, and U0126 revealed that PI3K/Akt signaling pathway interplayed with MAPK signaling pathways. Moreover, chicoric acid induced reactive oxygen species (ROS) generation. Pretreatment with the antioxidant N-acetylcysteine (NAC) significantly blocked cell death and changes of Akt and MAPK signalings induced by chicoric acid. In addition, chicoric acid down regulated HO-1 and COX-2 via the PI3K/Akt pathway.

  2. The MEKK1 PHD ubiquitinates TAB1 to activate MAPKs in response to cytokines.

    PubMed

    Charlaftis, Nikolaos; Suddason, Tesha; Wu, Xuefeng; Anwar, Saba; Karin, Michael; Gallagher, Ewen

    2014-11-03

    Unlike the other MAP3Ks, MEKK1 (encoded by Map3k1) contains a PHD motif. To understand the role of this motif, we have created a knockin mutant of mouse Map3k1 (Map3k1(m) (PHD)) with an inactive PHD motif. Map3k1(m) (PHD) ES cells demonstrate that the MEKK1 PHD controls p38 and JNK activation during TGF-β, EGF and microtubule disruption signalling, but does not affect MAPK responses to hyperosmotic stress. Protein microarray profiling identified the adaptor TAB1 as a PHD substrate, and TGF-β- or EGF-stimulated Map3k1(m) (PHD) ES cells exhibit defective non-canonical ubiquitination of MEKK1 and TAB1. The MEKK1 PHD binds and mediates the transfer of Lys63-linked poly-Ub, using the conjugating enzyme UBE2N, onto TAB1 to regulate TAK1 and MAPK activation by TGF-β and EGF. Both the MEKK1 PHD and TAB1 are critical for ES-cell differentiation and tumourigenesis. Map3k1(m) (PHD) (/+) mice exhibit aberrant cardiac tissue, B-cell development, testis and T-cell signalling.

  3. Imaging Spatial Reorganization of a MAPK Signaling Pathway Using the Tobacco Transient Expression System

    PubMed Central

    Zhang, Ying; Dong, Juan

    2016-01-01

    Visualization of dynamic signaling events in live cells has been a challenge. We expanded an established transient expression system, the biomolecular fluorescent complementation (BiFC) assay in tobacco epidermal cells, from testing protein-protein interaction to monitoring spatial distribution of signal transduction in plant cells. In this protocol, we used the BiFC assay to show that the interaction and the signaling between the Arabidopsis MAPKKK YODA and MAPK6 occur at the plasma membrane. When the scaffold protein BASL was co-expressed, the YODA-MAPK interaction redistributed and spatially co-polarized with CFP-BASL. This modified tobacco expression system allows for quick examination of signaling localization and dynamic changes (less than 4 days) and can accommodate multiple of fluorescent protein colors (at least three). We also presented detailed methods to quantify protein distribution (asymmetric spatial localization, or "polarization") in tobacco cells. This advanced tobacco expression system has a potential to be used widely for quick testing of dynamic signaling events in live plant cells. PMID:27022690

  4. C5a Induces the Synthesis of IL-6 and TNF-α in Rat Glomerular Mesangial Cells through MAPK Signaling Pathways

    PubMed Central

    Ji, Mingde; Lu, Yanlai; Zhao, Chenhui; Gao, Wenxing; He, Fengxia; Zhang, Jing; Zhao, Dan; Qiu, Wen; Wang, Yingwei

    2016-01-01

    Inflammatory response has been reported to contribute to the renal lesions in rat Thy-1 nephritis (Thy-1N) as an animal model of human mesangioproliferative glomerulonephritis (MsPGN). Besides C5b-9 complex, C5a is also a potent pro-inflammatory mediator and correlated to severity of various nephritic diseases. However, the role of C5a in mediating pro-inflammatory cytokine production in rats with Thy-1N is poorly defined. In the present studies, the levels of C5a, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were first determined in the renal tissues of rats with Thy-1N. Then, the expression of IL-6 and TNF-α was detected in rat glomerular mesangial cells (GMC) stimulated with our recombinant rat C5a in vitro. Subsequently, the activation of mitogen-activated protein kinase (MAPK) signaling pathways (p38 MAPK, ERK1/2 and JNK) and their roles in the regulation of IL-6 and TNF-α production were examined in the GMC induced by C5a. The results showed that the levels of C5a, IL-6 and TNF-α were markedly increased in the renal tissues of Thy-1N rats. Rat C5a stimulation in vitro could up-regulate the expression of IL-6 and TNF-α in rat GMC, and the activation of MAPK signaling pathways was involved in the induction of IL-6 and TNF-α. Mechanically, p38 MAPK activation promoted IL-6 production, while either ERK1/2 or JNK activation promoted TNF-α production in the GMC with exposure to C5a. Taken together, these data implicate that C5a induces the synthesis of IL-6 and TNF-α in rat GMC through the activation of MAPK signaling pathways. PMID:27583546

  5. Methanol Extract of Croton Pycnanthus Benth. Inhibits Osteoclast Differentiation by Suppressing the MAPK and NF-κB Signaling Pathways

    PubMed Central

    Lee, Jiyeon

    2014-01-01

    Background Osteoclasts are differentiated from monocytes/macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-kappa B (NF-κB) ligand (RANKL). Croton pycnanthus Benth. (CPB) is a herbal plant that belongs to Euphorbiaceae family. The aim of this study was to investigate the effects of CPB on osteoclastogenesis and RANKL-dependent signaling pathways. Methods Methanol extract of CPB was obtained from International Biological Material Research Center. Osteoclast differentiation was achieved by culturing mouse bone marrow-derived macrophages (BMMs) with M-CSF and RANKL. Osteoclast numbers were evaluated by counting multinuclear cells positive for tartrate-resistant acid phosphatase (TRAP). mRNA and protein levels were analyzed by real-time polymerase chain reaction (PCR) and Western blotting, respectively. The activation of signaling molecules were assessed after acute stimulation of cells with high dose of RANKL by Western blotting with phospho-specific antibodies. Results CPB reduced the generation of TRAP-positive multinucleated cells and the activation of mitogen-activated protein kinase (MAPK) and NF-κB signaling pathways. The induction of the expression of c-Fos, nuclear factor-activated T cells c1 (NFATc1) and dendritic cell-specific transmembrane protein (DC-STAMP) by RANKL was also suppressed. Conclusions CPB exerts negative effects on osteoclast differentiation in response to the RANKL. The inhibitory mechanism involves the suppression of MAPK and NF-κB signaling pathways and subsequently the down-regulation of c-Fos and NFATc1 transcription factors. PMID:25489576

  6. Fc gamma receptor cross-linking activates p42, p38, and JNK/SAPK mitogen-activated protein kinases in murine macrophages: role for p42MAPK in Fc gamma receptor-stimulated TNF-alpha synthesis.

    PubMed

    Rose, D M; Winston, B W; Chan, E D; Riches, D W; Gerwins, P; Johnson, G L; Henson, P M

    1997-04-01

    Fc gamma R cross-linking on murine macrophages resulted in the activation of mitogen-activated protein kinase (MAPK) family members p42MAPK, p38, and c-Jun NH2-terminal kinase (JNK)/stress-activated protein kinase (SAPK). The temporal pattern of activation was distinct for each kinase. p42MAPK activation peaked at 5 min after receptor cross-linking, while peak p38 activity occurred 5 to 10 min later. Maximal JNK/SAPK activation occurred 20 min after Fc gamma R cross-linking. The selective MAPK/extracellular signal-regulated kinase-1 (MEK-1) inhibitor PD 098059 inhibited activation of p42MAPK induced by Fc gamma R cross-linking, but not p38 or JNK/SAPK activation. PD 098059 also inhibited the synthesis of TNF-alpha induced by Fc gamma R cross-linking (IC50 approximately 0.1 microM). Together, these results suggest that 1) the activation of MAPKs may play a role in Fc gammaR signal transduction, and 2) the activation of p42MAPK is necessary for Fc gamma R cross-linking-induced TNF-alpha synthesis.

  7. Mitogen-activated protein kinases (MAPKs) regulate IL-6 over-production during concomitant influenza virus and Staphylococcus aureus infection

    PubMed Central

    Klemm, Carolin; Bruchhagen, Christin; van Krüchten, Andre; Niemann, Silke; Löffler, Bettina; Peters, Georg; Ludwig, Stephan; Ehrhardt, Christina

    2017-01-01

    Bacterial super-infections are a major complication of influenza virus (IV) infections and often lead to severe pneumonia. One hallmark of IV-associated Staphylococcus aureus (S. aureus) infection is rapid progression to a serious disease outcome. Changes in immune and inflammatory host responses increase morbidity and complicate efficient therapy. A key player during inflammation is the multifunctional cytokine IL-6. Although increased IL-6 levels have been observed after severe disease upon IV and/or bacterial super-infection, the underlying molecular mechanisms still remain to be elucidated. In the present study, we focused on cellular signalling pathways regulating IL-6 production upon IV/S. aureus super-infection. Additionally, infection with viable bacteria was mimicked by lipoteichoic acid stimulation in this model. Analyses of cellular signalling mechanisms revealed synergistically increased activation of the MAPK p38 as well as enhanced phosphorylation of the MAPKs ERK1/2 and JNK in the presence of super-infecting bacteria. Interestingly, inhibition of MAPK activity indicated a strong dependence of IL-6 expression on p38 and ERK1/2, while the MAPK JNK seems not to be involved. Thus, our results provide new molecular insights into the regulation of IL-6, a marker of severe disease, which might contribute to the lethal synergism of IV and S. aureus. PMID:28195157

  8. Obacunone exhibits anti-proliferative and anti-aromatase activity in vitro by inhibiting the p38 MAPK signaling pathway in MCF-7 human breast adenocarcinoma cells.

    PubMed

    Kim, Jinhee; Jayaprakasha, G K; Patil, Bhimanagouda S

    2014-10-01

    Overexpression of the aromatase enzyme CYP19 has been implicated in the onset of estrogen-dependent breast carcinogenesis. Obacunone, a natural compound present in citrus fruits, has been demonstrated for various biological activities including anti-cancer and anti-inflammatory properties. In the present study, we have isolated obacunone and obacunone glucoside (OG) from lemon seeds, then fractionated these compounds using chromatographic techniques and characterized them by HPLC, LC-MS, and 2D NMR spectral analysis. To investigate the mechanism of anti-cancer and anti-aromatase activities of limonoids, their cytotoxic effect was tested on human breast cancer (MCF-7) and non-malignant (MCF-12F) breast cells. MTT assays confirmed that obacunone was strongly inhibited MCF-7 cell proliferation without affecting non-malignant breast cells. Treatment with obacunone increased apoptosis by up-regulating expression of the pro-apoptotic protein Bax and down-regulating the anti-apoptotic protein Bcl2, as well as inducing G1 cell cycle arrest. In addition, obacunone significantly inhibited aromatase activity in an in vitro enzyme assay. Exposure of MCF-7 breast cancer cells to obacunone down-regulated expression of inflammatory molecules including nuclear factor-kappa B (NF-κB) and cyclooxygenase-2 (COX-2). Furthermore, we found that obacunone inhibited COX-2 and NF-κB by activation of the p38 mitogen-activated protein kinase (MAPK). Finally, the uptake level of obacunone into MCF-7 cells was measured by HPLC and its structure was confirmed by LC-HR-MS. This study demonstrated that obacunone may have the potential to prevent estrogen-responsive breast cancer through inhibition of the aromatase enzyme and inflammatory pathways, as well as activation of apoptosis.

  9. Attenuation of Magnesium Sulfate on CoCl₂-Induced Cell Death by Activating ERK1/2/MAPK and Inhibiting HIF-1α via Mitochondrial Apoptotic Signaling Suppression in a Neuronal Cell Line.

    PubMed

    Huang, Chih-Yang; Hsieh, You-Liang; Ju, Da-Tong; Lin, Chien-Chung; Kuo, Chia-Hua; Liou, Yi-Fan; Ho, Tsung-Jung; Tsai, Chang-Hai; Tsai, Fuu-Jen; Lin, Jing-Ying

    2015-08-31

    Magnesium sulfate (MgSO₄) ameliorates hypoxia/ischemia-induced neuronal apoptosis in a rat model. This study aimed to investigate the mechanisms governing the anti-apoptotic effect of MgSO₄ on cobalt chloride (CoCl₂)-exposed NB41A3 mouse neuroblastoma cells. MgSO₄ increased the viability of NB41A3 cells treated with CoCl₂ in a dose-dependent manner. MgSO₄ treatment was shown to lead to an increase in the anti-apoptotic Bcl-2 family proteins, with a concomitant decrease in the pro-apoptotic proteins. MgSO₄ also attenuated the CoCl₂-induced disruption of mitochondrial membrane potential (ΔΨ(m)) and reduced the release of cytochrome c form the mitochondria to the cytosol. Furthermore, exposure to CoCl₂ caused activation of the hypoxia-inducible factor 1α (HIF-1α). On the other hand, MgSO₄ markedly reduced CoCl₂-induced HIF-1α activation and suppressed HIF-1α downstream protein BNIP3. MgSO₄ treatment induced ERK1/2 activation and attenuated CoCl₂-induced activation of p38 and JNK. Addition of the ERK1/2 inhibitor U0126 significantly reduced the ability of MgSO₄ to protect neurons from CoCl₂-induced mitochondrial apoptotic events. However, incubation of cultures with the p38 and JNK inhibitors did not significantly affect MgSO₄-mediated neuroprotection. MgSO₄ appears to suppress CoCl₂-induced NB41A3 cell death by activating ERK1/2/ MAPK pathways, which further modulates the role of Bcl-2 family proteins and mitochondria in NB41A3 cells. Our data suggest that MgSO₄ may act as a survival factor that preserves mitochondrial integrity and inhibits apoptotic pathways.

  10. 2-Chloroethanol Induced Upregulation of Matrix Metalloproteinase-2 in Primary Cultured Rat Astrocytes Via MAPK Signal Pathways

    PubMed Central

    Sun, Qi; Liao, Yingjun; Wang, Tong; Tang, Hongge; Wang, Gaoyang; Zhao, Fenghong; Jin, Yaping

    2017-01-01

    This study was to explore the mechanisms underlying 1,2-dichloroethane (1,2-DCE) induced brain edema by focusing on alteration of matrix metalloproteinase-2 (MMP-2) in rat astrocytes induced by 2-chloroethanol (2-CE), an intermediate metabolite of 1,2-DCE in vivo. Protein and mRNA levels of MMP-2, and the phosphorylated protein levels of p38 MAPK (p-p38), extracellular signal regulated protein kinase (p-ERK1/2) and c-Jun N-terminal kinase (p-JNK1/2) in astrocytes were examined by immunostaining, western blot or real-time RT-PCR analysis. Findings from this study disclosed that protein levels of MMP-2 were upregulated by 2-CE in astrocytes. Meanwhile, protein levels of p-p38, p-ERK1/2 and p-JNK1/2 were also increased apparently in the cells treated with 2-CE. Moreover, pretreatment of astrocytes with SB202190 (inhibitor of p38 MAPK), U0126 (inhibitor of ERK1/2) or SP600125 (inhibitor of JNK1/2) could suppress the upregulated expression of p-p38, p-ERK1/2, and p-JNK1/2. In response to suppressed protein levels of p-p38 and p-JNK1/2, the protein levels of MMP-2 also decreased significantly, indicating that activation of MAPK signal pathways were involved in the mechanisms underlying 2-CE-induced upregulation of MMP-2 expression. PMID:28101000

  11. Hypoxia-inducible factor-2 alpha promotes the proliferation of human placenta-derived mesenchymal stem cells through the MAPK/ERK signaling pathway

    PubMed Central

    Zhu, Chengxing; Yu, Jiong; Pan, Qiaoling; Yang, Jinfeng; Hao, Guangshu; Wang, Yingjie; Li, Lanjuan; Cao, Hongcui

    2016-01-01

    Human placenta-derived mesenchymal stem cells (hPMSCs) reside in a physiologically low-oxygen microenvironment. Hypoxia influences a variety of stem cell cellular activities, frequently involving hypoxia-inducible factor-2 alpha (HIF-2α). This research showed that hPMSCs cultured in hypoxic conditions (5% O2) exhibited a more naïve morphology and had a higher proliferative capability and higher HIF-2α expression than hPMSCs cultured in normoxic conditions (21% O2). Similar to the hypoxic cultures, hPMSCs over-expressing HIF-2α showed higher proliferative potential and higher expression of CCND1 (CyclinD1), MYC (c-Myc), POU5F1 (Oct4) and the components of the MAPK/ERK pathway. In contrast, these genes were down-regulated in the HIF-2α-silenced hPMSCs. After adding the MAPK/ERK inhibitor PD0325901, cell growth and the expression of CCND1 and MYC were inhibited. Furthermore, the chromatin immunoprecipitation (ChIP) assay and electrophoretic mobility shift assay (EMSA) showed that HIF-2α bound to the MAPK3 (ERK1) promoter, indicative of its direct regulation of MAPK/ERK components at the transcriptional level during hPMSC expansion. Taken together, our results suggest that HIF-2α facilitated the preservation of hPMSC stemness and promoted their proliferation by regulating CCND1 and MYC through the MAPK/ERK signaling pathway. PMID:27765951

  12. Lipid raft localization of epidermal growth factor receptor alters matrix metalloproteinase-1 expression in SiHa cells via the MAPK/ERK signaling pathway

    PubMed Central

    Zhang, Zongfeng; Wang, Lina; Du, Juan; Li, Yuanbo; Yang, Huilun; Li, Chenxi; Li, Hui; Hu, Haiyang

    2016-01-01

    Matrix metalloproteinase-1 (MMP-1) has been identified as an important participant in tumor invasion, metastasis and angiogenesis. The purpose of the present study was to investigate the effects of epidermal growth factor receptor (EGFR) localization to lipid rafts on signaling pathways involved in the regulation of MMP-1 expression in SiHa cells, a cervical cancer cell line. EGFR activation by EGF specifically induced MMP-1 expression at both the messenger RNA and protein levels. Additionally, it was observed that EGFR localized to lipid rafts, and that the redistribution of EGFR induced by lipid raft disruption strengthened EGF-induced MMP-1 expression. MMP-1 induction was blocked by the mitogen-activated protein kinase (MAPK) kinase inhibitors PD98059 and U0126. Our results suggested that lipid rafts provide a platform to inhibit EGFR regulation of MMP-1 in SiHa cells through the MAPK/extracellular signal-regulated kinase signaling pathway. PMID:28101233

  13. Role of amygdala MAPK activation on immobility behavior of forced swim rats.

    PubMed

    Huang, Tung-Yi; Lin, Chih-Hung

    2006-10-02

    The role of amygdala mitogen-activated protein kinase (MAPK) in rats during a forced swim test was investigated. The variation of amygdala MAPK level was studied in control rats and early-life maternally deprived rats. A forced swim test was carried out to estimate the immobility level. The data showed that the immobility time of rats that received maternal deprivation in early life was longer than that of control rats and Western blot analysis also showed that the amygdala phospho-MAPK level in maternally deprived rats was almost two times higher than in control rats. Intra-amygdala infusion of PD098059 or U0126, MEK inhibitors, suppressed immobility behavior during the forced swim test in both rats. Western blot analysis also showed that the amygdala MAPK activities in both rats infused with MEK inhibitors were also suppressed in parallel with expression of immobility behavior. The suppressed MAPK activities as well as the restoration of immobility time returned to the original level 48 h later. These results suggest that amygdala MAPK activation might play a role in the regulation of immobility behavior in rats during the forced swim test. Moreover, it could provide a hint that amygdala MAPK activation might be involved in the formation of depression-like behavior.

  14. Alpha-1-antitrypsin suppresses oxidative stress in preeclampsia by inhibiting the p38MAPK signaling pathway: An in vivo and in vitro study

    PubMed Central

    Ding, Jian; Yuan, Hua; Yang, Lan; Xu, Jian-Juan; Hu, Ling-Qin

    2017-01-01

    This present study was designed to investigate the effects of alpha-1-antitrypsin (AAT) on oxidative stress in preeclampsia (PE) by regulating p38 mitogen-activated protein kinase (p38MAPK) signaling pathway. HTR8/SVneo cells were randomly assigned into normal, hypoxia/reoxygenation (H/R), HR + AAT and HR + siRNA-AAT groups. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used to detect the mRNA and protein expressions of p-p38MAPK, AAT, signal transducer and activator of transcription 1 (STAT1) and activating transcription factor2 (ATF2). Flow cytometry, scratch test, cell counting kit-8 (CCK-8) assay and the 3-(4,5)-dimethylthiazol (-z-y1)-3,5-di- phenyltetrazolium bromide (MTT) assay were conducted to detect reactive oxygen species (ROS) and cell apoptosis, cell migration, proliferation and cytotoxicity, respectively. Mouse models in PE were established, which were divided into normal pregnancy (NP), PE and PE + AAT groups with blood pressure and urine protein measured. Chromatin immunoprecipitation (ChIP) and enzyme-linked immunosorbent assay (ELISA) were conducted to detect the activity of oxidative stress-related kinases and expressions of inflammatory cytokines and coagulation-related factors in cells and mice placenta. Immunohistochemistry, Western blotting and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were performed to detect AAT and p38MAPK expressions, apoptosis-related protein expressions, and apoptosis rate in mice placenta. Compared with the normal group, the H/R group had decreased expression of AAT, activity of superoxide dismutase (SOD) and GSH-Px, cell proliferation and migration, but increased p38MAPK, STAT1, ATF2, MDA, H2O2, inflammatory cytokines, coagulation-related factors, cell cytotoxicity, ROS, apoptotic factors and apoptosis rate. Compared with the H/R group, the HR + ATT group had increased expressions of AAT, activity of SOD and GSH-Px, cell proliferation and

  15. Fibroblast growth factor 2 induces E-cadherin down-regulation via PI3K/Akt/mTOR and MAPK/ERK signaling in ovarian cancer cells.

    PubMed

    Lau, Man-Tat; So, Wai-Kin; Leung, Peter C K

    2013-01-01

    Fibroblast growth factor 2 (FGF2) is produced by ovarian cancer cells and it has been suggested to play an important role in tumor progression. In this study, we report that FGF2 treatment down-regulated E-cadherin by up-regulating its transcriptional repressors, Slug and ZEB1, in human ovarian cancer cells. The pharmacological inhibition of phosphatidylinositol-3-kinase (PI3K), mammalian target of rapamycin (mTOR), and MEK suggests that both PI3K/Akt/mTOR and MAPK/ERK signaling are required for FGF2-induced E-cadherin down-regulation. Moreover, FGF2 up-regulated Slug and ZEB1 expression via the PI3K/Akt/mTOR and MAPK/ERK signaling pathways, respectively. Finally, FGF2-induced cell invasion was abolished by the inhibition of the PI3K/Akt/mTOR and MAPK/ERK pathways, and the forced expression of E-cadherin diminished the intrinsic invasiveness of ovarian cancer cells as well as the FGF2-induced cell invasion. This study demonstrates a novel mechanism in which FGF2 down-regulates E-cadherin expression through the activation of PI3K/Akt/mTOR and MAPK/ERK signaling, and the up-regulation of Slug and ZEB1 in human ovarian cancer cells.

  16. Isorhamnetin prevent endothelial cell injuries from oxidized LDL via activation of p38MAPK.

    PubMed

    Bao, Meihua; Lou, Yijia

    2006-10-10

    endothelial cell line EA.hy926 from ox-LDL-induced cell injuries. These effects were obtained via inhibition of lectin-like ox-LDL receptor-1 upregulation, interference of ox-LDL-mediated intracellular signaling pathway (p38MAPK activation, NF-kappaB nuclear translocation, eNOS expression) and the antioxidant activity of isorhamnetin.

  17. Zearalenone Mycotoxin Affects Immune Mediators, MAPK Signalling Molecules, Nuclear Receptors and Genome-Wide Gene Expression in Pig Spleen

    PubMed Central

    Pistol, Gina Cecilia; Braicu, Cornelia; Motiu, Monica; Gras, Mihail Alexandru; Marin, Daniela Eliza; Stancu, Mariana; Calin, Loredana; Israel-Roming, Florentina; Berindan-Neagoe, Ioana; Taranu, Ionelia

    2015-01-01

    The toxicity of zearalenone (ZEA) was evaluated in swine spleen, a key organ for the innate and adaptative immune response. Weaned pigs were fed for 18 days with a control or a ZEA contaminated diet. The effect of ZEA was assessed on wide genome expression, pro- (TNF-α, IL-8, IL-6, IL-1β, IFN-γ) and anti-inflammatory (IL-10, IL-4) cytokines, other molecules involved in inflammatory processes (MMPs/TIMPs), as well as signaling molecules, (p38/JNK1/JNK2-MAPKs) and nuclear receptors (PPARγ/NFkB/AP-1/STAT3/c-JUN). Microarray analysis showed that 46% of total number of differentially expressed genes was involved in cellular signaling pathway, 13% in cytokine network and 10% in the inflammatory response. ZEA increased expression and synthesis of pro- inflammatory (TNF-α, IL-8, IL-6, IL-1β) and had no effect on IFN-γ, IL-4 and IL-10 cytokines in spleen. The inflammatory stimulation might be a consequence of JNK pathway activation rather than of p-38MAPK and NF-kB involvement whose gene and protein expression were suppressed by ZEA action. In summary, our findings indicated the role of ZEA as an immune disruptor at spleen level. PMID:26011631

  18. 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

  19. Fasciola hepatica tegumental coat antigen suppresses MAPK signalling in dendritic cells and up-regulates the expression of SOCS3.

    PubMed

    Vukman, K V; Adams, P N; O'Neill, S M

    2013-07-01

    Fasciola hepatica tegumental coat antigen (FhTeg) suppresses dendritic cell maturation and function by inhibiting IL-6, tumour necrosis factor (TNF)-α, IL-10 and IL-12 production and CD80, CD86 and CD40 cell surface marker expression in TLR4-stimulated dendritic cells. Fasciola hepatica also impairs dendritic cell function by inhibiting its phagocytic capacity and its ability to prime T cells. We have shown previously that activation of mast cells with bacterial ligands is also inhibited by FhTeg. Fasciola hepatica suppresses LPS-induced NF-κB and MAPK pathway (ERK) activation in these cells. Previously, we demonstrated that FhTeg induces expression of suppressor of cytokine signalling (SOCS)3, a negative regulator of the TLR pathway in mast cells. In this study, we show the same inhibitory effect of FhTeg on the activation of the other members of the MAPKs pathway (ERK, p38, JNK) in dendritic cells and demonstrate an enhanced expression of SOCS3, but not SOCS1, SOCS5 or PIAS3 in this process. These studies enhance our understanding of the immunomodulatory effect of helminth molecules on the TLR pathway.

  20. Mitogen-activated protein kinase cascades in signaling plant growth and development.

    PubMed

    Xu, Juan; Zhang, Shuqun

    2015-01-01

    Mitogen-activated protein kinase (MAPK) cascades are ubiquitous signaling modules in eukaryotes. Early research of plant MAPKs has been focused on their functions in immunity and stress responses. Recent studies reveal that they also play essential roles in plant growth and development downstream of receptor-like protein kinases (RLKs). With only a limited number of MAPK components, multiple functional pathways initiated from different receptors often share the same MAPK components or even a complete MAPK cascade. In this review, we discuss how MAPK cascades function as molecular switches in response to spatiotemporal-specific ligand-receptor interactions and the availability of downstream substrates. In addition, we discuss other possible mechanisms governing the functional specificity of plant MAPK cascades, a question central to our understanding of MAPK functions.

  1. Daily sesame oil supplementation attenuates local renin-angiotensin system via inhibiting MAPK activation and oxidative stress in cardiac hypertrophy.

    PubMed

    Liu, Chuan-Teng; Liu, Ming-Yie

    2017-04-01

    The renin-angiotensin system (RAS) is involved in the development of left ventricular hypertrophy (LVH) by which increases cardiac morbidity and mortality. Activation of mitogen-activated protein kinases (MAPKs) and oxidative stress are important in RAS-mediated cardiac hypertrophy. Sesame oil, a potent antioxidant, attenuates hypertension-dependent LVH. We examined the protective role of sesame oil on RAS-mediated MAPK activation and oxidative stress in rats. We induced LVH using a hypertensive model by subcutaneously injecting deoxycorticosterone acetate (DOCA; 15 mg/ml/kg in mineral oil; twice weekly for 5 weeks) and supplementing with 1% sodium chloride drinking water (DOCA/salt) to uninephrectomized rats. Sesame oil was gavaged (0.5 or 1 ml/kg/day for 7 days) after 4 weeks of DOCA/salt treatment. Cardiac histopathology, RAS parameters, expression of MAPKs, reactive oxygen species and lipid peroxidation were assessed 24 h after the last dose of sesame oil. Sesame oil significantly decreased the size of cardiomyocytes and the levels of cardiac renin, angiotensin-converting enzyme and angiotensin II. In addition, sesame oil down-regulated the expression of angiotensin type 1 receptor, JNK and p38 MAPK and apoptosis signal regulating kinase 1, c-Fos and c-Jun in rats receiving DOCA/salt. Furthermore, the induction of nicotinamide adenine dinucleotide phosphate oxidase, superoxide anion and hydroxyl radical and lipid peroxidation by DOCA/salt were inhibited by sesame oil. Sesame oil modulates cardiac RAS to ameliorate LVH by inhibiting MAPK activation and lowering oxidative stress.

  2. [Regulatory mechanism of p38MAPK signaling pathway on renal tissue inflammation in chronic kidney disease and interventional effect of traditional Chinese medicine].

    PubMed

    Zhao, Qing; Wan, Yigang; Wang, Chaojun; Wei, Qingxue; Chen, Haoli; Meng, Xianjie; Yao, Jian

    2012-06-01

    The inflammatory reaction of renal tissues and its relevant tissue damages (such as glomerulosclerosis and renal interstitial fibrosis) are important factors for the development of chronic kidney diseases (CKD) to end-state renal diseases. Of them, p38 mitogen-activated protein kinase (MAPK) signaling pathway plays an important role in regulating expression and bioactivity of multiple nuclear transcription factors, impacting synthesis of downstream inflammatory mediators and activating inflammatory cells. Some monomer traditional Chinese medicines and their extracts (such as emodin and berberine) and some traditional Chinese medicine compound prescriptions (such as Yishen Huoxue decoction) can affect inflammatory reaction of renal tissues by regulating p38MAPK signaling pathway, thas improving reduce glomerulus and renal interstitial inflammatory injury.

  3. HnRNP-L mediates bladder cancer progression by inhibiting apoptotic signaling and enhancing MAPK signaling pathways.

    PubMed

    Lv, Daojun; Wu, Huayan; Xing, Rongwei; Shu, Fangpeng; Lei, Bin; Lei, Chengyong; Zhou, Xumin; Wan, Bo; Yang, Yu; Zhong, Liren; Mao, Xiangming; Zou, Yaguang

    2017-01-11

    Heterogeneous nuclear ribonucleoprotein L (hnRNP-L) is a promoter of various kinds of cancers, but its actions in bladder cancer (BC) are unclear. In this study, we investigated the function and the underlying mechanism of hnRNP-L in bladder carcinogenesis. Our results demonstrated that enhanced hnRNP-L expression in BC tissues was associated with poor overall survival of BC patients. Depletion of hnRNP-L significantly suppressed cell proliferation in vitro and inhibited xenograft tumor growth in vivo. Furthermore, downregulation of hnRNP-L resulted in G1-phase cell cycle arrest and enhanced apoptosis accompanied by inhibition of EMT and cell migration. All these cellular changes were reversed by ectopic expression of hnRNP-L. Deletion of hnRNP-L resulted in decreased expression of Bcl-2, enhanced expression of caspases-3, -6 and -9 and inhibition of the MAPK signaling pathway. These findings demonstrate that hnRNP-L contributes to poor prognosis and tumor progression of BC by inhibiting the intrinsic apoptotic signaling and enhancing MAPK signaling pathways.

  4. LL202 protects against dextran sulfate sodium-induced experimental colitis in mice by inhibiting MAPK/AP-1 signaling

    PubMed Central

    Zhao, Yue; Hu, Yang; Li, Zhiyu; Guo, Qinglong; Zhao, Kai; Lu, Na

    2016-01-01

    LL202, a newly-synthesized flavonoid derivative, has been reported to inhibit inflammatory-induced angiogenesis. However, the exact role of LL202 in inflammation along with its mechanism has not been explored. In this study, we investigated the anti-inflammatory effect of LL202 on intestinal inflammation by establishing dextran sulfate sodium (DSS)-induced experimental colitis. LL202 attenuated DSS-induced body weight loss, colon length shortening and colonic pathological damage. The inflammatory cells infiltration, myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) activities were decreased by LL202 in a dose-dependent manner. LL202 reduced the production of pro-inflammatory cytokines in serum and colon of DSS-induced mice as well. Mechanically, LL202 could decrease the expression and nuclear translation of AP-1 to protect against DSS-induced colitis. In lipopolysaccharide (LPS)-induced THP-1 cells, LL202 markedly decreased the secretion, mRNA level and protein expression of IL-1β, IL-6 and TNF-α via inhibiting ERK/JNK/p38 MAPK pathways and the nuclear translocation of AP-1. Furthermore, these findings were confirmed in LPS-induced bone marrow derived macrophages (BMDM). In conclusion, our study demonstrated that LL202 could exert its anti-inflammatory effect via inhibiting MAPK/AP-1 signaling, which suggested that LL202 might be a potential effective drug for the treatment of inflammatory bowel diseases. PMID:27590510

  5. Neospora caninum Activates p38 MAPK as an Evasion Mechanism against Innate Immunity

    PubMed Central

    Mota, Caroline M.; Oliveira, Ana C. M.; Davoli-Ferreira, Marcela; Silva, Murilo V.; Santiago, Fernanda M.; Nadipuram, Santhosh M.; Vashisht, Ajay A.; Wohlschlegel, James A.; Bradley, Peter J.; Silva, João S.; Mineo, José R.; Mineo, Tiago W. P.

    2016-01-01

    Due to the high prevalence and economic impact of neosporosis, the development of safe and effective vaccines and therapies against this parasite has been a priority in the field and is crucial to limit horizontal and vertical transmission in natural hosts. Limited data is available regarding factors that regulate the immune response against this parasite and such knowledge is essential in order to understand Neospora caninum induced pathogenesis. Mitogen-activated protein kinases (MAPKs) govern diverse cellular processes, including growth, differentiation, apoptosis, and immune-mediated responses. In that sense, our goal was to understand the role of MAPKs during the infection by N. caninum. We found that p38 phosphorylation was quickly triggered in macrophages stimulated by live tachyzoites and antigen extracts, while its chemical inhibition resulted in upregulation of IL-12p40 production and augmented B7/MHC expression. In vivo blockade of p38 resulted in an amplified production of cytokines, which preceded a reduction in latent parasite burden and enhanced survival against the infection. Additionally, the experiments indicate that the p38 activation is induced by a mechanism that depends on GPCR, PI3K and AKT signaling pathways, and that the phenomena here observed is distinct that those induced by Toxoplasma gondii’s GRA24 protein. Altogether, these results showed that N. caninum manipulates p38 phosphorylation in its favor, in order to downregulate the host’s innate immune responses. Additionally, those results infer that active interference in this signaling pathway may be useful for the development of a new therapeutic strategy against neosporosis. PMID:27679624

  6. Endothelial lipase is upregulated by interleukin-6 partly via the p38 MAPK and p65 NF-κB signaling pathways

    PubMed Central

    Yue, Xin; Wu, Minghui; Jiang, Hong; Hao, Jing; Zhao, Qinghao; Zhu, Qing; Saren, Gaowa; Zhang, Yun; Zhang, Xiaoli

    2016-01-01

    To investigate the effects of inflammatory factor interleukin (IL)-6 on the expression of endothelial lipase (EL) and its potential signaling pathways in atherosclerosis, a primary culture of human umbilical vein endothelial cells (HUVECs) was established and treated as follows: i) Control group without any treatment; ii) recombinant human (rh)IL-6 treatment (10 ng/ml) for 0, 4, 8, 12 and 24 h; iii) p38 mitogen-activated protein kinases (MAPKs) inhibitor (SB203580, 10 µmol/l) pretreatment for 1 h prior to rhIL-6 (10 ng/ml) treatment; iv) nuclear factor (NF)-κB activation inhibitor (pyrrolidine dithiocarbamate, 10 mmol/l) pretreatment for 1 h prior to rhIL-6 (10 ng/ml) treatment. EL levels were detected by immunocytochemical staining and western blot analysis. Proliferation of HUVECs was detected by immunostaining of proliferating cell nuclear antigen (PCNA) and an MTT assay. p38 MAPK and NF-κB p65 levels were detected by western blotting. The results showed that rhIL-6 treatment increased EL expression and proliferation of HUVECs. NF-κB p65 and MAPK p38 protein levels also increased in a time-dependent manner in HUVECs after rhIL-6 treatment. NF-κB inhibitor and MAPK p38 inhibitor prevented the effects of rhIL-6 on EL expression. In conclusion, inflammatory factor IL-6 may participate in the pathogenesis of atherosclerosis by increasing EL expression and the proliferation of endothelial cells via the p38 MAPK and NF-κB signaling pathways. PMID:27430252

  7. Maternal Inheritance of Twist and Analysis of MAPK Activation in Embryos of the Polychaete Annelid Platynereis dumerilii

    PubMed Central

    Pfeifer, Kathrin; Schaub, Christoph; Domsch, Katrin; Dorresteijn, Adriaan; Wolfstetter, Georg

    2014-01-01

    In this study, we aimed to identify molecular mechanisms involved in the specification of the 4d (mesentoblast) lineage in Platynereis dumerilii. We employ RT-PCR and in situ hybridization against the Platynereis dumerilii twist homolog (Pdu-twist) to reveal mesodermal specification within this lineage. We show that Pdu-twist mRNA is already maternally distributed. After fertilization, ooplasmatic segregation leads to relocation of Pdu-twist transcripts into the somatoblast (2d) lineage and 4d, indicating that the maternal component of Pdu-twist might be an important prerequisite for further mesoderm specification but does not represent a defining characteristic of the mesentoblast. However, after the primordial germ cells have separated from the 4d lineage, zygotic transcription of Pdu-twist is exclusively observed in the myogenic progenitors, suggesting that mesodermal specification occurs after the 4d stage. Previous studies on spiral cleaving embryos revealed a spatio-temporal correlation between the 4d lineage and the activity of an embryonic organizer that is capable to induce the developmental fates of certain micromeres. This has raised the question if specification of the 4d lineage could be connected to the organizer activity. Therefore, we aimed to reveal the existence of such a proposed conserved organizer in Platynereis employing antibody staining against dpERK. In contrast to former observations in other spiralian embryos, activation of MAPK signaling during 2d and 4d formation cannot be detected which questions the existence of a conserved connection between organizer function and specification of the 4d lineage. However, our experiments unveil robust MAPK activation in the prospective nephroblasts as well as in the macromeres and some micromeres at the blastopore in gastrulating embryos. Inhibition of MAPK activation leads to larvae with a shortened body axis, defects in trunk muscle spreading and improper nervous system condensation, indicating a

  8. Cortactin promotes colorectal cancer cell proliferation by activating the EGFR-MAPK pathway

    PubMed Central

    Zhang, Tao; Wang, Zhenlei; Qin, Xuan; Jing, Xiaoqian; Wu, Haoxuan; Ji, Xiaopin; He, Yonggang; Zhao, Ren

    2017-01-01

    Cortactin (CTTN) is overexpressed in various tumors, including head and neck squamous cell carcinoma and colorectal cancer (CRC), and can serve as a biomarker of cancer metastasis. We observed that CTTN promotes cancer cell proliferation in vitro and increases CRC tumor xenograft growth in vivo. CTTN expression increases EGFR protein levels and enhances the activation of the MAPK signaling pathway. CTTN expression also inhibits the ubiquitin-mediated degradation of EGFR by suppressing the coupling of c-Cbl with EGFR. CoIP experiments indicate CTTN can interact with c-Cbl in CRC cells. These results demonstrate that CTTN promotes the proliferation of CRC cells and suppresses the degradation of EGFR. PMID:27903975

  9. G-CSF improves CUMS-induced depressive behaviors through downregulating Ras/ERK/MAPK signaling pathway.

    PubMed

    Li, Hui; Linjuan-Li; Wang, Yaping

    2016-10-28

    Neuronal plasticity in hippocampal neurons is closely related to memory, mood and behavior as well as in the development of depression. Granulocyte colony-stimulating factor (G-CSF) can promote neuronal plasticity and enhance motor skills. However, the function of G-CSF in depression remains poorly understood. In this study, we explored the biological role and potential molecular mechanism of G-CSF on depression-like behaviors. Our results showed that G-CSF was significantly downregulated in the hippocampus of chronic unexpected mild stress (CUMS) rats. Administration of G-CSF significantly reversed CUMS-induced depression-like behaviors in the open field test (OFT), sucrose preference test (SPT) and forced swimming test (FST). Moreover, G-CSF upregulated the expression of synaptic-associated proteins including polysialylated form of neural cell adhesion molecule (PSA-NCAM), synaptophysin (SYN), and postsynaptic density protein 95 (PSD-95) in the hippocampus and G-CSF significantly increased cell viability rate of hippocampal neurons in vitro. Further studies indicated that the renin-angiotensin system (Ras)/extracellular signal-regulated kinase (ERK)/p38 mitogen-activated protein kinase (MAPK) signaling pathways was involved in the regulation of G-CSF on depressive-like behaviors and neuronal plasticity in CUMS rats. Taken together, our results showed that G-CSF improves depression-like behaviors via inhibiting Ras/ERK/MAPK signaling pathways. Our study suggests that G-CSF may be a promising therapeutic strategy for the treatment of depression.

  10. Frankincense and myrrh suppress inflammation via regulation of the metabolic profiling and the MAPK signaling pathway

    PubMed Central

    Su, Shulan; Duan, Jinao; Chen, Ting; Huang, Xiaochen; Shang, Erxin; Yu, Li; Wei, Kaifeng; Zhu, Yue; Guo, Jianming; Guo, Sheng; Liu, Pei; Qian, Dawei; Tang, Yuping

    2015-01-01

    Frankincense and myrrh are highly effective in treatment of inflammatary diseases, but lacking of the therapy mechanisms. We undertook this stuty to evaluate the effects on Adjuvant-induced Arthritis (AIA) rats and to explore the underlying mechanisms by analyzing the metabolic profiling and signaling pathway evaluated by expression of inflammatory cytokines, c-jun and c-fos and corresponding phosphorylation levels. The results stated the elevated expression levels of TNFα, PGE2, IL-2, NO, and MDA in serum and swelling paw of AIA rats were significantly decreased after treatment, which exerted more remarkable inhibitive effects of combined therapy. The metbolic profiling of plasma and urine were clearly improved and twenty-one potential biomarkers were identified. Moreover, the inhibited effects of five bioactive components on cytokine transcription in PHA stimulated-PBMC showed the MAPK pathway might account for this phenomenon with considerable reduction in phosphorylated forms of all the three MAPK (ERK1/2, p38 and JNK) and down regulation of c-jun and c-fos. PMID:26329643

  11. Protective Role of Fucoidan in Cerebral Ischemia-Reperfusion Injury through Inhibition of MAPK Signaling Pathway.

    PubMed

    Che, Nan; Ma, Yijie; Xin, Yinhu

    2016-11-25

    Fucoidan has been reported to exhibit various beneficial activities ranging from to antivirus and anticancer properties. However, little information is available about the effects of fucoidan on cerebral ischemia-reperfusion injury (IRI). Our study aimed to explore the effects of fucoidan on cerebral IRI, as well as the underlying mechanisms. Sprague-Dawley (SD) rats were randomly subjected to four groups: Sham, IRI+saline (IRI+S), IRI+80 mg/kg fucoidan (IRI+F80), and IRI+160 mg/kg fucoidan (IRI+F160). Fucoidan (80 mg/kg or 160 mg/kg) was intraperitoneally injected from 7 days before the rats were induced to cerebral IRI model with middle cerebral artery occlusion (MCAO) method. At 24 h after reperfusion, neurological deficits and the total infarct volume were determined. The levels of inflammation-associated cytokines (interleukin (IL)-1β, IL-6, myeloperoxidase (MPO), and tumor necrosis factor (TNF)-α), oxidative stress-related proteins (malondialdehyde (MDA) and superoxide dismutase (SOD)) in the ischemic brain were measured by enzyme-linked immunosorbent assay (ELISA). Besides, the levels of apoptosis-related proteins (p-53, Bax, and B-cell lymphoma (Bcl)-2) and mitogen-activated protein kinase (MAPK) pathway (phosphorylation-extracellular signalregulated kinase (p-ERK), p-c-Jun N-terminal kinase (JNK), and p-p38) were measured. Results showed that administration of fucoidan significantly reduced the neurological deficits and infarct volume compared to the IRI+S group in a dose-dependent manner. Also, fucoidan statistically decreased the levels of inflammation-associated cytokines, and oxidative stress-related proteins, inhibited apoptosis, and suppressed the MAPK pathway. So, Fucoidan plays a protective role in cerebral IRI might be by inhibition of MAPK pathway.

  12. Coordination of Satellite Cell Activation and Self-Renewal by Par-Complex-Dependent Asymmetric Activation of p38α/β MAPK

    PubMed Central

    Troy, Andrew; Cadwallader, Adam B.; Fedorov, Yuri; Tyner, Kristina; Tanaka, Kathleen Kelly; Olwin, Bradley B.

    2014-01-01

    SUMMARY In response to muscle injury, satellite cells activate the p38α/β MAPK pathway to exit quiescence, then proliferate, repair skeletal muscle, and self-renew, replenishing the quiescent satellite cell pool. Although satellite cells are capable of asymmetric division, the mechanisms regulating satellite cell self-renewal are not understood. We found that satellite cells, once activated, enter the cell cycle and a subset undergoes asymmetric division, renewing the satellite cell pool. Asymmetric localization of the Par complex activates p38α/β MAPK in only one daughter cell, inducing MyoD, which permits cell cycle entry and generates a proliferating myoblast. The absence of p38α/β MAPK signaling in the other daughter cell prevents MyoD induction, renewing the quiescent satellite cell. Thus, satellite cells employ a mechanism to generate distinct daughter cells, coupling the Par complex and p38α/β MAPK signaling to link the response to muscle injury with satellite cell self-renewal. PMID:23040480

  13. Coxiella burnetii lipopolysaccharide blocks p38α-MAPK activation through the disruption of TLR-2 and TLR-4 association

    PubMed Central

    Conti, Filippo; Boucherit, Nicolas; Baldassarre, Veronica; Trouplin, Virginie; Toman, Rudolf; Mottola, Giovanna; Mege, Jean-Louis; Ghigo, Eric

    2015-01-01

    To survive in macrophages, Coxiella burnetii hijacks the activation pathway of macrophages. Recently, we have demonstrated that C. burnetii, via its lipopolysaccharide (LPS), avoids the activation of p38α-MAPK through an antagonistic engagement of Toll-like receptor (TLR)-4. We investigated the fine-tuned mechanism leading to the absence of activation of the p38α-MAPK despite TLR-4 engagement. In macrophages challenged with LPS from the avirulent variants of C. burnetii, TLR-4 and TLR-2 co-immunoprecipitated. This association was absent in cells challenged by the LPS of pathogenic C. burnetii. The disruption makes TLRs unable to signal during the recognition of the LPS of pathogenic C. burnetii. The disruption of TLR-2 and TLR-4 was induced by the re-organization of the macrophage cytoskeleton by C. burnetii LPS. Interestingly, blocking the actin cytoskeleton re-organization relieved the disruption of the association TLR-2/TLR-4 by pathogenic C. burnetii and rescued the p38α-MAPK activation by C. burnetii. We elucidated an unexpected mechanism allowing pathogenic C. burnetii to avoid macrophage activation by the disruption of the TLR-2 and TLR-4 association. PMID:25610812

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

    PubMed

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

    2016-09-01

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

  15. SIRT1 protects rat lung tissue against severe burn-induced remote ALI by attenuating the apoptosis of PMVECs via p38 MAPK signaling

    PubMed Central

    Bai, Xiaozhi; Fan, Lei; He, Ting; Jia, Wenbin; Yang, Longlong; Zhang, Jun; Liu, Yang; Shi, Jihong; Su, Linlin; Hu, Dahai

    2015-01-01

    Silent information regulator type-1 (SIRT1) has been reported to be involved in the cardiopulmonary protection. However, its role in the pathogenesis of burn-induced remote acute lung injury (ALI) is currently unknown. The present study aims to investigate the role of SIRT1 in burn-induced remote ALI and the involved signaling pathway. We observed that SIRT1 expression in rat lung tissue after burn injury appeared an increasing trend after a short period of suppression. The upregulation of SIRT1 stimulated by resveratrol exhibited remission of histopathologic changes, reduction of cell apoptosis, and downregulation of pro-inflammatory cytokines in rat pulmonary tissues suffering from severe burn. We next used primary pulmonary microvascular endothelial cells (PMVECs) challenged by burn serum (BS) to simulate in vivo rat lung tissue after burn injury, and found that BS significantly suppressed SIRT1 expression, increased cell apoptosis, and activated p38 MAPK signaling. The use of resveratrol reversed these effects, while knockdown of SIRT1 by shRNA further augmented BS-induced increase of cell apoptosis and activation of p38 MAPK. Taken together, these results indicate that SIRT1 might protect lung tissue against burn-induced remote ALI by attenuating PMVEC apoptosis via p38 MAPK signaling, suggesting its potential therapeutic effects on the treatment of ALI. PMID:25992481

  16. The problem of pyridinyl imidazole class inhibitors of MAPK14/p38α and MAPK11/p38β in autophagy research.

    PubMed

    Menon, Manoj B; Dhamija, Sonam; Kotlyarov, Alexey; Gaestel, Matthias

    2015-01-01

    In addition to its established role in inflammation, the stress-activated p38 MAP kinase pathway plays major roles in the regulation of cell cycle, senescence, and autophagy. Robust studies could establish mechanistic links between MAPK11-MAPK14/p38 signaling and macroautophagy converging at ATG9-trafficking and BECN1 phosphorylation. However, several reports seem to monitor MAPK11-MAPK14/p38-dependence of autophagy exclusively by the use of the SB203580/SB202190 class of MAPK14/MAPK11/p38α/β inhibitors. In this "Letter to the editor" we present data to support our claim that these inhibitors interfere with autophagic flux in a MAPK11-MAPK14/p38-independent manner and hence should no longer be used as pharmacological tools in the analysis of MAPK11-MAPK14/p38-dependence of autophagy. We propose a general guideline from Autophagy with regard to this issue to avoid such misinterpretations in the future.

  17. MAPK pathway activation by chronic lead-exposure increases vascular reactivity through oxidative stress/cyclooxygenase-2-dependent pathways

    SciTech Connect

    Simões, Maylla Ronacher; Aguado, Andrea; Fiorim, Jonaína; Silveira, Edna Aparecida; Azevedo, Bruna Fernandes; Toscano, Cindy Medice; Zhenyukh, Olha; Briones, Ana María; Alonso, María Jesús; Vassallo, Dalton Valentim; Salaices, Mercedes

    2015-03-01

    Chronic exposure to low lead concentration produces hypertension; however, the underlying mechanisms remain unclear. We analyzed the role of oxidative stress, cyclooxygenase-2-dependent pathways and MAPK in the vascular alterations induced by chronic lead exposure. Aortas from lead-treated Wistar rats (1st dose: 10 μg/100 g; subsequent doses: 0.125 μg/100 g, intramuscular, 30 days) and cultured aortic vascular smooth muscle cells (VSMCs) from Sprague Dawley rats stimulated with lead (20 μg/dL) were used. Lead blood levels of treated rats attained 21.7 ± 2.38 μg/dL. Lead exposure increased systolic blood pressure and aortic ring contractile response to phenylephrine, reduced acetylcholine-induced relaxation and did not affect sodium nitroprusside relaxation. Endothelium removal and L-NAME left-shifted the response to phenylephrine more in untreated than in lead-treated rats. Apocynin and indomethacin decreased more the response to phenylephrine in treated than in untreated rats. Aortic protein expression of gp91(phox), Cu/Zn-SOD, Mn-SOD and COX-2 increased after lead exposure. In cultured VSMCs lead 1) increased superoxide anion production, NADPH oxidase activity and gene and/or protein levels of NOX-1, NOX-4, Mn-SOD, EC-SOD and COX-2 and 2) activated ERK1/2 and p38 MAPK. Both antioxidants and COX-2 inhibitors normalized superoxide anion production, NADPH oxidase activity and mRNA levels of NOX-1, NOX-4 and COX-2. Blockade of the ERK1/2 and p38 signaling pathways abolished lead-induced NOX-1, NOX-4 and COX-2 expression. Results show that lead activation of the MAPK signaling pathways activates inflammatory proteins such as NADPH oxidase and COX-2, suggesting a reciprocal interplay and contribution to vascular dysfunction as an underlying mechanisms for lead-induced hypertension. - Highlights: • Lead-exposure increases oxidative stress, COX-2 expression and vascular reactivity. • Lead exposure activates MAPK signaling pathway. • ROS and COX-2 activation by

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

    PubMed

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

    2016-01-01

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

  19. MAPK-dependent JA and SA signalling in Nicotiana attenuata affects plant growth and fitness during competition with conspecifics

    PubMed Central

    2012-01-01

    Background Induced defense responses to herbivores are generally believed to have evolved as cost-saving strategies that defer the fitness costs of defense metabolism until these defenses are needed. The fitness costs of jasmonate (JA)-mediated defenses have been well documented. Those of the early signaling units mediating induced resistance to herbivores have yet to be examined. Early signaling components that mediate herbivore-induced defense responses in Nicotiana attenuata, have been well characterized and here we examine their growth and fitness costs during competition with conspecifics. Two mitogen-activated protein kinases (MAPKs), salicylic acid (SA)-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK) are rapidly activated after perception of herbivory and both kinases regulate herbivory-induced JA levels and JA-mediated defense metabolite accumulations. Since JA-induced defenses result in resource-based trade-offs that compromise plant productivity, we evaluated if silencing SIPK (irSIPK) and WIPK (irWIPK) benefits the growth and fitness of plants competiting with wild type (WT) plants, as has been shown for plants silenced in JA-signaling by the reduction of Lipoxygenase 3 (LOX3) levels. Results As expected, irWIPK and LOX3-silenced plants out-performed their competing WT plants. Surprisingly, irSIPK plants, which have the largest reductions in JA signaling, did not. Phytohormone profiling of leaves revealed that irSIPK plants accumulated higher levels of SA compared to WT. To test the hypothesis that these high levels of SA, and their presumed associated fitness costs of pathogen associated defenses in irSIPK plants had nullified the JA-deficiency-mediated growth benefits in these plants, we genetically reduced SA levels in irSIPK plants. Reducing SA levels partially recovered the biomass and fitness deficits of irSIPK plants. We also evaluated whether the increased fitness of plants with reduced SA or JA levels resulted from

  20. Polyubiquitination of Transforming Growth Factor β-activated Kinase 1 (TAK1) at Lysine 562 Residue Regulates TLR4-mediated JNK and p38 MAPK Activation

    PubMed Central

    Chen, I-Ting; Hsu, Pang-Hung; Hsu, Wan-Ching; Chen, Nien-Jung; Tseng, Ping-Hui

    2015-01-01

    Toll-like receptor 4 (TLR4) plays an important role in innate immunity by eliciting inflammation. Upon receptor engagement, transforming growth factor β-activated kinase 1 (TAK1) is an essential mediator that transmits a signal from the receptor to downstream effectors, IκB kinase (IKK) and the mitogen-activated protein kinases (MAPKs), which control the production of inflammatory cytokines. However, the association between phosphorylation and ubiquitination of TAK1 is not yet clear. Here, we examined the crosstalk between phosphorylation and polyubiquitination of TAK1 and further investigated the mechanism of distinct activation of MAPKs and IKK. Inhibition of TAK1 phosphorylation enhanced Lys63-linked polyubiquitination of TAK1. Conversely, ubiquitin modification was counteracted by phospho-mimic TAK1 mutant, T(184,187)D. Moreover, using LC-MS analysis, Lys562 of TAK1 was identified as a novel Lys63-linked ubiquitination site and as the key residue in the feedback regulation. Mutation of Lys562 of TAK1 leads to a decrease in TAK1 phosphorylation and specific inhibition of the MAPK pathway, but has no effect on formation of the TAK1-containing complex. Our findings demonstrate a feedback loop for phosphorylation and ubiquitination of TAK1, indicating a dynamic regulation between TAK1 polyubiquitiantion and phosphorylated activation, and the molecular mechanism by which IKK and MAPKs are differentially activated in the TLR4 pathway. PMID:26189595

  1. Hypoxia-Inducible Factor-1alpha and MAPK Co-Regulate Activation of Hepatic Stellate Cells upon Hypoxia Stimulation

    PubMed Central

    Guan, Fei; Xiao, Yan; Deng, Jing; Chen, Huoying; Chen, Xiaolin; Li, Jianrong; Huang, Hanju; Shi, Chunwei

    2013-01-01

    Background Hepatic stellate cell (HSC) plays a key role in pathogenesis of liver fibrosis. During liver injury, hypoxia in local micro-environment is inevitable. Hif-1α is the key transcriptional regulation factor that induces cell’s adaptive responses to hypoxia. Recently, it was reported that MAPK is involved in regulation of Hif-1α activity. Aims To explore whether Hif-1α regulates HSC activation upon hypoxia, and whether MAPK affects Hif-1α-regulated signaling cascades, thus providing new targets for preventing liver fibrosis. Methods Hif-1α expression in livers of Schistosomajaponicum infected BALB/c mice was detected with western blot and immunohistochemistry. A rat cell line of HSC, HSC-T6, was cultured in 1% oxygen. HSC activation, including F-actin reorganization, increase of vimentin and α-SMA, was detected with western blot or immunocytochemistry. Cells were transfected with specific siRNA to Hif-1α, expression of activation markers, transcription of fibrosis-promoting cytokines, secretion of collagen I were detected with western blot, Real Time PCR and ELISA. Lysate from HSC-T6 cells pretreated with PD98059, a specific MEK1 pharmacological inhibitor, was subjected to detect Hif-1α ubiquitination and nuclear translocation with western blot and immunoprecipitation. Results and Conclusions Hif-1α apparently increased in liver tissues of Schistosomajaponicum infected mice. 1% O2 induced F-actin reorganization, increase of Hif-1α, vimentin and α-SMA in HSC-T6 cells. Hif-1α Knockdown inhibited HSC-T6 activation, transcription of IL-6, TGF-β and CTGF and secretion of collagen I from HSC-T6 cells upon hypoxia. Inhibition of MAPK phosphorylation enhanced Hif-1α ubiquitination, and inhibited Hif-1α translocation into nucleus. Conclusively, Hif-1α and MAPK participate in HSC activation upon hypoxia. PMID:24040163

  2. Differential Effects of E2 on MAPK Activity in the Brain and Heart of Aged Female Rats

    PubMed Central

    Shults, Cody L.; Rao, Yathindar S.; Pak, Toni R.

    2016-01-01

    Aging and the coincident loss of circulating estrogens at menopause lead to increased risks for neurological and cardiovascular pathologies. Clinical studies show that estrogen therapy (ET) can be beneficial in mitigating these negative effects, in both the brain and heart, when it is initiated shortly after the perimenopausal transition. However, this same therapy is detrimental when initiated >10 years postmenopause. Importantly, the molecular mechanisms underlying this age-related switch in ET efficacy are unknown. Estrogen receptors (ERs) mediate the neuroprotective and cardioprotective functions of estrogens by modulating gene transcription or, non-genomically, by activating second messenger signaling pathways, such as mitogen activated protein kinases (MAPK). These kinases are critical regulators of cell signaling pathways and have widespread downstream effects. Our hypothesis is that age and estrogen deprivation following menopause alters the expression and activation of the MAPK family members p38 and ERK in the brain and heart. To test this hypothesis, we used a surgically induced model of menopause in 18 month old rats through bilateral ovariectomy (OVX) followed by an acute dose of 17β-estradiol (E2) administered at varying time points post-OVX (1 week, 4 weeks, 8 weeks, or 12 weeks). Age and E2 treatment differentially regulated kinase activity in both the brain and heart, and the effects were also brain region specific. MAPK signaling plays an integral role in aging, and the aberrant regulation of those signaling pathways might be involved in age-related disorders. Clinical studies show benefits of ET during early menopause but detrimental effects later, which might be reflective of changes in kinase expression and activation status. PMID:27487271

  3. Interleukin-4 regulates macrophage polarization via the MAPK signaling pathway to protect against atherosclerosis.

    PubMed

    Zhao, X N; Li, Y N; Wang, Y T

    2016-02-22

    Our study aimed to investigate the effects of interleukin-4 (IL-4) on macrophage polarization, as well as its role in the development of atherosclerosis. Human peripheral blood mononuclear cells (PBMCs) were isolated and randomly divided into 3 groups: control group, ox-LDL group, and ox-LDL + IL-4 groups. The expression of M1/M2 macrophage surface markers such as TNF-α, CD68, and CD206 were analyzed by western blot. Cell viability was determined using the MTT assay. Measurement of CD86/CD206 expression ratio (M1/M2 ratio) was performed via flow cytometry. In addition, ApoE(-/-) mice on a C57BL/6 background were subjected to high-fat diets, and were used as a model of atherosclerosis. Atherosclerotic lesion area was quantified after mice were treated with ox-LDL and IL-4. Finally, expression of phosphorylated MAPK signaling molecules such as p-ERK and p-JNK was quantified using western blot. The expression of TNF-α and CD86 markedly increased after cells were treated with ox-LDL, whereas the expression of CD206 markedly increased after PBMCs were treated with IL-4. It is possible that IL-4 could decrease ox-LDL-induced cell viability and the CD86/CD206 (M1/M2) ratio. Additionally, IL-4 intervention attenuated ox-LDL-induced atherosclerotic lesions in ApoE(-/-) mice, and decreased ox- LDL-induced expression of p-ERK and p-JNK. Our findings indicate that IL-4 may induce macrophages to take on an M2 phenotype in order to resolve inflammation via inhibition of MAPK signaling pathways, thereby protecting against atherosclerosis. IL-4 may serve as an intervention target for atherosclerosis.

  4. MAGI1 inhibits migration and invasion via blocking MAPK/ERK signaling pathway in gastric cancer

    PubMed Central

    Jia, Shuqin; Lu, Jiajia; Qu, Tingting; Feng, Yi; Wang, Xiaohong; Liu, Caixia; Ji, Jiafu

    2017-01-01

    Objective To explore the association of membrane-associated guanylate kinase inverted 1 (MAGI1) with gastric cancer (GC) and the related molecular mechanisms. Methods The reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) were utilized to measure the MAGI1 expression level in GC tissues. Quantitative real-time PCR and Western blotting were used to ensure the MAGI1 expression in GC cell lines. Small hairpin RNA (shRNA) was applied for knockdown of endogenous MAGI1 in GC cells. MTT assay and colony formation assay, scratch wounding migration assay and transwell chamber migration assay, as well as transwell chamber invasion assay were employed respectively to investigate the GC cell proliferation, migration and invasion in MAGI1-knockdown and control GC cells. The potential molecular mechanism mediated by MAGI1 was studied using Western blotting and RT- PCR. Results RT-PCR and IHC verified MAGI1 was frequently expressed in matched adjacent noncancerous mucosa compared with GC tissues and the expression of MAGI1 was related to clinical pathological parameters. Functional assays indicated that MAGI1 knockdown significantly promoted GC cell migration and invasion. Further mechanism investigation demonstrated that one pathway of MAGI1 inhibiting migration and invasion was mainly by altering the expression of matrix metalloproteinases (MMPs) and epithelial-mesenchymal transition (EMT)-related molecules via inhibiting MAPK/ERK signaling pathway. Conclusions MAGI1 was associated with GC clinical pathological parameters and acted as a tumor suppressor via inhibiting of MAPK/ERK signaling pathway in GC. PMID:28373751

  5. The pore-forming α-toxin from clostridium septicum activates the MAPK pathway in a Ras-c-Raf-dependent and independent manner.

    PubMed

    Chakravorty, Anjana; Awad, Milena M; Cheung, Jackie K; Hiscox, Thomas J; Lyras, Dena; Rood, Julian I

    2015-02-10

    Clostridium septicum is the causative agent of atraumatic gas gangrene, with α-toxin, an extracellular pore-forming toxin, essential for disease. How C. septicum modulates the host's innate immune response is poorly defined, although α-toxin-intoxicated muscle cells undergo cellular oncosis, characterised by mitochondrial dysfunction and release of reactive oxygen species. Nonetheless, the signalling events that occur prior to the initiation of oncosis are poorly characterised. Our aims were to characterise the ability of α-toxin to activate the host mitogen activated protein kinase (MAPK) signalling pathway both in vitro and in vivo. Treatment of Vero cells with purified α-toxin activated the extracellular-signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 arms of the MAPK pathway and stimulated the release of TNF-α in a dose-dependent manner. Studies using inhibitors of all three MAPK components suggested that activation of ERK occurred in a Ras-c-Raf dependent manner, whereas activation of JNK and p38 occurred by a Ras-independent mechanism. Toxin-mediated activation was dependent on efficient receptor binding and pore formation and on an influx of extracellular calcium ions. In the mouse myonecrosis model we showed that the MAPK pathway was activated in tissues of infected mice, implying that it has an important role in the disease process.

  6. Dissecting Cell-Fate Determination Through Integrated Mathematical Modeling of the ERK/MAPK Signaling Pathway.

    PubMed

    Shin, Sung-Young; Nguyen, Lan K

    2017-01-01

    The past three decades have witnessed an enormous progress in the elucidation of the ERK/MAPK signaling pathway and its involvement in various cellular processes. Because of its importance and complex wiring, the ERK pathway has been an intensive subject for mathematical modeling, which facilitates the unraveling of key dynamic properties and behaviors of the pathway. Recently, however, it became evident that the pathway does not act in isolation but closely interacts with many other pathways to coordinate various cellular outcomes under different pathophysiological contexts. This has led to an increasing number of integrated, large-scale models that link the ERK pathway to other functionally important pathways. In this chapter, we first discuss the essential steps in model development and notable models of the ERK pathway. We then use three examples of integrated, multipathway models to investigate how crosstalk of ERK signaling with other pathways regulates cell-fate decision-making in various physiological and disease contexts. Specifically, we focus on ERK interactions with the phosphoinositide-3 kinase (PI3K), c-Jun N-terminal kinase (JNK), and β-adrenergic receptor (β-AR) signaling pathways. We conclude that integrated modeling in combination with wet-lab experimentation have been and will be instrumental in gaining an in-depth understanding of ERK signaling in multiple biological contexts.

  7. Effects of Maternal Chromium Restriction on the Long-Term Programming in MAPK Signaling Pathway of Lipid Metabolism in Mice.

    PubMed

    Zhang, Qian; Sun, Xiaofang; Xiao, Xinhua; Zheng, Jia; Li, Ming; Yu, Miao; Ping, Fan; Wang, Zhixin; Qi, Cuijuan; Wang, Tong; Wang, Xiaojing

    2016-08-10

    It is now broadly accepted that the nutritional environment in early life is a key factor in susceptibility to metabolic diseases. In this study, we evaluated the effects of maternal chromium restriction in vivo on the modulation of lipid metabolism and the mechanisms involved in this process. Sixteen pregnant C57BL mice were randomly divided into two dietary treatments: a control (C) diet group and a low chromium (L) diet group. The diet treatment was maintained through gestation and lactation period. After weaning, some of the pups continued with either the control diet or low chromium diet (CC or LL), whereas other pups switched to another diet (CL or LC). At 32 weeks of age, serum lipid metabolism, proinflammatory indexes, oxidative stress and anti-oxidant markers, and DNA methylation status in adipose tissue were measured. The results indicated that the maternal low chromium diet increased body weight, fat pad weight, serum triglyceride (TG), low-density lipoprotein cholesterol (LDL), tumor necrosis factor-α (TNF-α), malondialdehyde (MDA), and oxidized glutathione (GSSG). There was a decrease in serum reduced/oxidized glutathione (GSH/GSSG) ratio at 32 weeks of age in female offspring. From adipose tissue, we identified 1214 individual hypomethylated CpG sites and 411 individual hypermethylated CpG sites in the LC group when compared to the CC group. Pathway analysis of the differential methylation genes revealed a significant increase in hypomethylated genes in the mitogen-activated protein kinase (MAPK) signaling pathway in the LC group. Our study highlights the importance of the MAPK signaling pathway in epigenetic changes involved in the lipid metabolism of the offspring from chromium-restricted dams.

  8. Effects of Maternal Chromium Restriction on the Long-Term Programming in MAPK Signaling Pathway of Lipid Metabolism in Mice

    PubMed Central

    Zhang, Qian; Sun, Xiaofang; Xiao, Xinhua; Zheng, Jia; Li, Ming; Yu, Miao; Ping, Fan; Wang, Zhixin; Qi, Cuijuan; Wang, Tong; Wang, Xiaojing

    2016-01-01

    It is now broadly accepted that the nutritional environment in early life is a key factor in susceptibility to metabolic diseases. In this study, we evaluated the effects of maternal chromium restriction in vivo on the modulation of lipid metabolism and the mechanisms involved in this process. Sixteen pregnant C57BL mice were randomly divided into two dietary treatments: a control (C) diet group and a low chromium (L) diet group. The diet treatment was maintained through gestation and lactation period. After weaning, some of the pups continued with either the control diet or low chromium diet (CC or LL), whereas other pups switched to another diet (CL or LC). At 32 weeks of age, serum lipid metabolism, proinflammatory indexes, oxidative stress and anti-oxidant markers, and DNA methylation status in adipose tissue were measured. The results indicated that the maternal low chromium diet increased body weight, fat pad weight, serum triglyceride (TG), low-density lipoprotein cholesterol (LDL), tumor necrosis factor-α (TNF-α), malondialdehyde (MDA), and oxidized glutathione (GSSG). There was a decrease in serum reduced/oxidized glutathione (GSH/GSSG) ratio at 32 weeks of age in female offspring. From adipose tissue, we identified 1214 individual hypomethylated CpG sites and 411 individual hypermethylated CpG sites in the LC group when compared to the CC group. Pathway analysis of the differential methylation genes revealed a significant increase in hypomethylated genes in the mitogen-activated protein kinase (MAPK) signaling pathway in the LC group. Our study highlights the importance of the MAPK signaling pathway in epigenetic changes involved in the lipid metabolism of the offspring from chromium-restricted dams. PMID:27517955

  9. Ceftiofur impairs pro-inflammatory cytokine secretion through the inhibition of the activation of NF-{kappa}B and MAPK

    SciTech Connect

    Ci Xinxin; Song Yu; Zeng Fanqin; Zhang Xuemei; Li Hongyu; Wang Xinrui; Cui Junqing Deng Xuming

    2008-07-18

    Ceftiofur is a new broad-spectrum, third-generation cephalosporin antibiotic for veterinary use. Immunopharmacological studies can provide new information on the immunomodulatory activities of some drugs, including their effect on cytokine productions. For this reason, we investigated the effect of ceftiofur on cytokine productions in vitro. We found that ceftiofur can downregulate tumor necrosis factor-{alpha} (TNF-{alpha}), interleukin-1{beta} (IL-1{beta}), and interleukin-6 (IL-6), but did not affect interleukin-10 (IL-10) production. We further investigated signal transduction mechanisms to determine how ceftiofur affects. RAW 264.7 cells were pretreated with 1, 5, or 10 mg/L of ceftiofur 1 h prior to treatment with 1 mg/L of LPS. Thirty minutes later, cells were harvested and mitogen activated protein kinases (MAPKs) activation was measured by Western blot. Alternatively, cells were fixed and nuclear factor-{kappa}B (NF-{kappa}B) activation was measured using immunocytochemical analysis. Signal transduction studies showed that ceftiofur significantly inhibited extracellular signal-regulated kinase (ERK), p38, and c-jun NH{sub 2}-terminal kinase (JNK) phosphorylation protein expression. Ceftiofur also inhibited p65-NF-{kappa}B translocation into the nucleus. Therefore, ceftiofur may inhibit LPS-induced production of inflammatory cytokines by blocking NF-{kappa}B and MAPKs signaling in RAW264.7 cells.

  10. Resveratrol mitigates lipopolysaccharide-mediated acute inflammation in rats by inhibiting the TLR4/NF-κBp65/MAPKs signaling cascade

    PubMed Central

    Wang, Guangxi; Hu, Zhiqiang; Fu, Qiuting; Song, Xu; Cui, Qiankun; Jia, Renyong; Zou, Yuanfeng; He, Changliang; Li, Lixia; Yin, Zhongqiong

    2017-01-01

    Resveratrol (RSV) is a natural compound exhibiting anti-inflammatory effect, but the anti-inflammatory mechanism has not been fully understood. This study is aimed to evaluate the anti-inflammatory activity and mechanism of RSV in lipopolysaccharides-induced rats’ model. The visceral wet/dry weight ratios and the changes of hematologic and biochemical indices indicated that LPS- stimulation mainly caused damages to liver and lung, while pretreatment with RSV could alleviate the lesions. The cytokine assays showed that RSV could markedly decrease the production of proinflammatory mediators and cytokines (IL-1, IL-1β, IL-6, NO, iNOS and COX-2), and increase the expression of anti-inflammatory mediator (IL-10). RSV could inhibit TLR4 signaling pathway by down-regulating the mRNA levels of MyD88 and TRAF6, and suppressing the TLR4 protein. RSV could inhibit the signaling cascades of NF-κBp65 and MAPKs through down-regulating the mRNA levels of IκBα, p38MAPK, JNK, ERK1, ERK2 and ERK5 in liver and lung, and suppressing the dynamic changes of proteins and phosphorylated proteins including IκBα, NF-κBp65, p38MAPK, JNK, ERK1/2 and ERK5 from tissue’s cytoplasm to nucleus. In conclusion, RSV possessed a therapeutic effect on LPS-induced inflammation in rats and the mechanism mainly attributed to suppressing the signaling cascades of NF-κBp65 and MAPKs by inhibiting the TLR4 signaling pathway. PMID:28322346

  11. Neuroprotective effects of cannabidiol in endotoxin-induced uveitis: critical role of p38 MAPK activation

    PubMed Central

    El-Remessy, A.B.; Tang, Y.; Zhu, G.; Matragoon, S.; Khalifa, Y.; Liu, E.K.; Liu, J-Y.; Hanson, E.; Mian, S.; Fatteh, N.

    2008-01-01

    Purpose Degenerative retinal diseases are characterized by inflammation and microglial activation. The nonpsychoactive cannabinoid, cannabidiol (CBD), is an anti-inflammatory in models of diabetes and glaucoma. However, the cellular and molecular mechanisms are largely unknown. We tested the hypothesis that retinal inflammation and microglia activation are initiated and sustained by oxidative stress and p38 mitogen-activated protein kinase (MAPK) activation, and that CBD reduces inflammation by blocking these processes. Methods Microglial cells were isolated from retinas of newborn rats. Tumor necrosis factor (TNF)-α levels were estimated with ELISA. Nitric oxide (NO) was determined with a NO analyzer. Superoxide anion levels were determined by the chemiluminescence of luminol derivative. Reactive oxygen species (ROS) was estimated by measuring the cellular oxidation products of 2’, 7’-dichlorofluorescin diacetate. Results In retinal microglial cells, treatment with lipopolysaccharide (LPS) induced immediate NADPH oxidase-generated ROS. This was followed by p38 MAPK activation and resulted in a time-dependent increase in TNF-α production. At a later phase, LPS induced NO, ROS, and p38 MAPK activation that peaked at 2-6 h and was accompanied by morphological change of microglia. Treatment with 1 μM CBD inhibited ROS formation and p38 MAPK activation, NO and TNF-α formation, and maintained cell morphology. In addition, LPS-treated rat retinas showed an accumulation of macrophages and activated microglia, significant levels of ROS and nitrotyrosine, activation of p38 MAPK, and neuronal apoptosis. These effects were blocked by treatment with 5 mg/kg CBD. Conclusions Retinal inflammation and degeneration in uveitis are caused by oxidative stress. CBD exerts anti-inflammatory and neuroprotective effects by a mechanism that involves blocking oxidative stress and activation of p38 MAPK and microglia. PMID:19052649

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

    PubMed Central

    Kim, Da Jung; Kim, Yong Sik

    2015-01-01

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

  13. Tension Force Downregulates Matrix Metalloproteinase Expression and Upregulates the Expression of Their Inhibitors through MAPK Signaling Pathways in MC3T3-E1 cells

    PubMed Central

    Karasawa, Yoko; Tanaka, Hideki; Nakai, Kumiko; Tanabe, Natsuko; Kawato, Takayuki; Maeno, Masao; Shimizu, Noriyoshi

    2015-01-01

    Objective: Matrix metalloproteinases (MMPs), produced by osteoblasts, catalyze the turnover of extracellular matrix (ECM) molecules in osteoid, and the regulation of MMP activity depends on interactions between MMPs and tissue inhibitors of metalloproteinases (TIMPs). We focused on the degradation process of ECM in osteoid that was exposed to mechanical strain, and conducted an in vitro study using MC3T3-E1 osteoblastic cells to examine the effects of tension force (TF) on the expression of MMPs and TIMPs, and activation of mitogen-activated protein kinase (MAPK) pathways. Design: Cells were incubated on flexible-bottomed culture plates and stimulated with or without cyclic TF for 24 hours. The expression of MMPs and TIMPs was examined at mRNA and protein levels by real-time RT-PCR and Western blotting, respectively. The phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38 MAPK, and stress-activated protein kinases/c-jun N-terminal kinases (SAPK/JNK) were examined by Western blotting. Results: TF decreased the expression of MMP-1, -3, -13 and phosphorylated ERK1/2. In contrast, TF increased the expression of TIMP-2, -3 and phosphorylated SAPK/JNK. The expression of MMP-2, -14, TIMP-1, -4 and phosphorylated p38 MAPK was unaffected by TF. MMP-1, -3 and -13 expression decreased in cells treated with the ERK inhibitor PD98059 compared with untreated control cells. The JNK inhibitor SP600125 inhibited the TF-induced upregulation of TIMP-2 and -3. Conclusions: The results suggest that TF suppresses the degradation process that occurs during ECM turnover in osteoid via decreased production of MMP-1, -3 and -13, and increased production of TIMP-2 and -3 through the MAPK signaling pathways in osteoblasts. PMID:26640410

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

    PubMed

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

    2015-07-31

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

  15. Berberine prevents nitric oxide-induced rat chondrocyte apoptosis and cartilage degeneration in a rat osteoarthritis model via AMPK and p38 MAPK signaling.

    PubMed

    Zhou, Yan; Liu, Shi-Qing; Yu, Ling; He, Bin; Wu, Shi-Hao; Zhao, Qi; Xia, Shao-Qiang; Mei, Hong-Jun

    2015-09-01

    Chondrocyte apoptosis is an important mechanism involved in osteoarthritis (OA). Berberine (BBR), a plant alkaloid derived from Chinese medicine, is characterized by multiple pharmacological effects, such as anti-inflammatory and anti-apoptotic activities. This study aimed to evaluate the chondroprotective effect and underlying mechanisms of BBR on sodium nitroprusside (SNP)-stimulated chondrocyte apoptosis and surgically-induced rat OA model. The in vitro results revealed that BBR suppressed SNP-stimulated chondrocyte apoptosis as well as cytoskeletal remodeling, down-regulated expressions of inducible nitric oxide synthase (iNOS) and caspase-3, and up-regulated Bcl-2/Bax ratio and Type II collagen (Col II) at protein levels, which were accompanied by increased adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and decreased phosphorylation of p38 mitogen-activated protein kinase (MAPK). Furthermore, the anti-apoptotic effect of BBR was blocked by AMPK inhibitor Compound C (CC) and adenosine-9-β-D-arabino-furanoside (Ara A), and enhanced by p38 MAPK inhibitor SB203580. In vivo experiment suggested that BBR ameliorated cartilage degeneration and exhibited an anti-apoptotic effect on articular cartilage in a rat OA model, as demonstrated by histological analyses, TUNEL assay and immunohistochemical analyses of caspase-3, Bcl-2 and Bax expressions. These findings suggest that BBR suppresses SNP-stimulated chondrocyte apoptosis and ameliorates cartilage degeneration via activating AMPK signaling and suppressing p38 MAPK activity.

  16. Low magnitude high frequency vibration promotes adipogenic differentiation of bone marrow stem cells via P38 MAPK signal

    PubMed Central

    Yu, Haiyang; Gan, Xueqi

    2017-01-01

    Low magnitude high frequency vibration (LMHFV) has been mainly reported for its influence on the musculoskeletal system, particularly the bone tissue. In the bone structure, osteogenic activity is the main focus of study with regards to LMHFV. However, adipogenesis, another important mode of differentiation in the bone marrow cavity that might be affected by LMHFV, is much less researched. Furthermore, the molecular mechanism of how LMHFV influences adipogenesis still needs to be understood. Here, we tested the effect of LMHFV (0.3g, 40 Hz, amplitude: 50μm), 15min/d, on multipotent stem cells (MSCs), which are the common progenitors of osteogenic, chondrogenic, adipogenic and myogenic cells. It is previously shown that LMHFV promotes osteogenesis of MSCs. In this study, we further revealed its effect on adipo-differentiation of bone marrow stem cells (BMSCs) and studied the underlying signaling pathway. We found that when treated with LMHFV, the cells showed a higher expression of PPARγ, C/EBPα, adiponectin and showed more oil droplets. After vibration, the protein expression of PPARγ increased, and the phosphorylation of p38 MAPK was enhanced. After treating cells with SB203580, a specific p38 inhibitor, both the protein level of PPARγ illustrated by immunofluorescent staining and the oil droplets number, were decreased. Altogether, this indicates that p38 MAPK is activated during adipogenesis of BMSCs, and this is promoted by LMHFV. Our results demonstrating that specific parameters of LMHFV promotes adipogenesis of MSCs and enhances osteogenesis, highlights an unbeneficial side effect of vibration therapy used for preventing obesity and osteoporosis. PMID:28253368

  17. The UV response of the skin: a review of the MAPK, NFkappaB and TNFalpha signal transduction pathways.

    PubMed

    Muthusamy, Visalini; Piva, Terrence J

    2010-01-01

    The sun emits different types of ultraviolet (UV) light. Our skin is a natural target of UV radiation which is involved in vitamin D3 production in our body. UV radiation at high doses is an environmental carcinogen which can elicit skin damage as well as inducing skin cancer. It can mediate inflammatory and immunological reactions through activation of receptors, DNA/RNA damage and production of reactive oxygen species. It is also involved in the release of pro-inflammatory cytokines, of which TNFalpha has been implicated in tumorigenic activities. In order to mediate its effects, UV radiation is known to activate multiple signalling cascades such as the p38 MAPK, Jun N-terminal kinase, extracellular signal-regulated kinase 1/2 and NFkappaB pathways in skin cells. The role each of these pathways plays in mediating the release of cytokines such as TNFalpha remains to be fully characterized. Once the function of these pathways is known, this information may provide for the formulation of therapy which will prevent the release of immunosuppressive cytokines resulting in a reduction in skin cancer formation.

  18. Requirement of ERα and basal activities of EGFR and Src kinase in Cd-induced activation of MAPK/ERK pathway in human breast cancer MCF-7 cells

    SciTech Connect

    Song, Xiulong Wei, Zhengxi; Shaikh, Zahir A.

    2015-08-15

    Cadmium (Cd) is a common environmental toxicant and an established carcinogen. Epidemiological studies implicate Cd with human breast cancer. Low micromolar concentrations of Cd promote proliferation of human breast cancer cells in vitro. The growth promotion of breast cancer cells is associated with the activation of MAPK/ERK pathway. This study explores the mechanism of Cd-induced activation of MAPK/ERK pathway. Specifically, the role of cell surface receptors ERα, EGFR, and Src kinase was evaluated in human breast cancer MCF-7 cells treated with 1–3 μM Cd. The activation of ERK was studied using a serum response element (SRE) luciferase reporter assay. Receptor phosphorylation was detected by Western blot analyses. Cd treatment increased both the SRE reporter activity and ERK1/2 phosphorylation in a concentration-dependent manner. Cd treatment had no effect on reactive oxygen species (ROS) generation. Also, blocking the entry of Cd into the cells with manganese did not diminish Cd-induced activation of MAPK/ERK. These results suggest that the effect of Cd was likely not caused by intracellular ROS generation, but through interaction with the membrane receptors. While Cd did not appear to activate either EGFR or Src kinase, their inhibition completely blocked the Cd-induced activation of ERK as well as cell proliferation. Similarly, silencing ERα with siRNA or use of ERα antagonist blocked the effects of Cd. Based on these results, it is concluded that not only ERα, but also basal activities of EGFR and Src kinase are essential for Cd-induced signal transduction and activation of MAPK/ERK pathway for breast cancer cell proliferation. - Highlights: • Low micromolar concentrations of Cd rapidly activate ERK1/2 in MCF-7 cells. • Signal transduction and resulting cell proliferation require EGFR, ERα, and Src. • These findings implicate Cd in promotion of breast cancer.

  19. Sensitivity of GBM cells to cAMP agonist-mediated apoptosis correlates with CD44 expression and agonist resistance with MAPK signaling

    PubMed Central

    Daniel, Paul M; Filiz, Gulay; Mantamadiotis, Theo

    2016-01-01

    In some cell types, activation of the second messenger cAMP leads to increased expression of proapoptotic Bim and subsequent cell death. We demonstrate that suppression of the cAMP pathway is a common event across many cancers and that pharmacological activation of cAMP in glioblastoma (GBM) cells leads to enhanced BIM expression and apoptosis in specific GBM cell types. We identified the MAPK signaling axis as the determinant of cAMP agonist sensitivity in GBM cells, with high MAPK activity corresponding to cAMP resistance and low activity corresponding to sensitization to cAMP-induced apoptosis. Sensitive cells were efficiently killed by cAMP agonists alone, while targeting both the cAMP and MAPK pathways in resistant GBM cells resulted in efficient apoptosis. We also show that CD44 is differentially expressed in cAMP agonist-sensitive and -resistant cells. We thus propose that CD44 may be a useful biomarker for distinguishing tumors that may be sensitive to cAMP agonists alone or cAMP agonists in combination with other pathway inhibitors. This suggests that using existing chemotherapeutic compounds in combination with existing FDA-approved cAMP agonists may fast track trials toward improved therapies for difficult-to-treat cancers, such as GBM. PMID:27906173

  20. GITRL modulates the activities of p38 MAPK and STAT3 to promote Th17 cell differentiation in autoimmune arthritis.

    PubMed

    Tang, Xinyi; Tian, Jie; Ma, Jie; Wang, Jiemin; Qi, Chen; Rui, Ke; Wang, Yungang; Xu, Huaxi; Lu, Liwei; Wang, Shengjun

    2016-02-23

    The glucocorticoid-induced TNFR family-related protein (GITR) and its ligand play a critical role in the pathogenesis of autoimmune arthritis by enhancing the Th17 cell response, but their molecular mechanisms remain largely unclear. This study aims to define the role of p38 mitogen-activated protein kinases (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling in GITRL-induced Th17 cells in autoimmune arthritis. We found that the p38 phosphorylation was enhanced by GITRL in activated CD4+T cells, and the p38 inhibitor restrained the GITRL-induced Th17 cell expansion in a dose-dependent manner. Moreover, there was decreased STAT3 activity on Tyr705 and Ser727 with the p38 inhibitor in vitro. Notably, the p38 inhibitor could prevent GITRL-treated arthritis progression and markedly decrease the Th17 cell percentages. The phosphorylation of the Tyr705 site was significantly lower in the GITRL-treated CIA mice administrated with the p38 inhibitor. A significantly higher phosphorylation of p38 was detected in RA patients and had a positive relationship with the serum level of anti-cyclic citrullinated peptide (anti-CCP) antibody. Our findings have indicated that GITRL could promote Th17 cell differentiation by p38 MAPK and STAT3 signaling in autoimmune arthritis.

  1. Modeling of the MAPK machinery activation in response to various abiotic and biotic stresses in plants by a system biology approach.

    PubMed

    Pathak, Rajesh Kumar; Taj, Gohar; Pandey, Dinesh; Arora, Sandeep; Kumar, Anil

    2013-01-01

    Mitogen-Activated Protein Kinases (MAPKs) cascade plays an important role in regulating plant growth and development, generating cellular responses to the extracellular stimuli. MAPKs cascade mainly consist of three sub-families i.e. mitogen-activated protein kinase kinase kinase (MAPKKK), mitogen-activated protein kinase kinase (MAPKK) and mitogen activated protein kinase (MAPK), several cascades of which are activated by various abiotic and biotic stresses. In this work we have modeled the holistic molecular mechanisms essential to MAPKs activation in response to several abiotic and biotic stresses through a system biology approach and performed its simulation studies. As extent of abiotic and biotic stresses goes on increasing, the process of cell division, cell growth and cell differentiation slow down in time dependent manner. The models developed depict the combinatorial and multicomponent signaling triggered in response to several abiotic and biotic factors. These models can be used to predict behavior of cells in event of various stresses depending on their time and exposure through activation of complex signaling cascades.

  2. Phosphorylation of zinc channel ZIP7 drives MAPK, PI3K and mTOR growth and proliferation signalling.

    PubMed

    Nimmanon, T; Ziliotto, S; Morris, S; Flanagan, L; Taylor, K M

    2017-02-16

    Zinc is an essential trace element participating in diverse biological processes. Cellular zinc levels are strictly controlled by two families of transport proteins: ZIP channels (SLC39A) and ZnT transporters (SLC30A). ZIP channels increase cytosolic zinc levels by importing zinc into cells or releasing zinc from intracellular stores such as the ER. Among all the 14 human members of the ZIP family, ZIP7 is a gatekeeper of zinc release from intracellular stores, requiring post-translational activation by phosphorylation on residues S275 and S276, resulting in activation of multiple downstream pathways. Employing site-directed mutagenesis, we investigated the importance of these individual serine residues as well as other predicted phosphorylation sites on ZIP7, showing that all four sites are required for maximal ZIP7 activation. Using phosphor-protein arrays, we also discovered the major signalling pathways that were activated as a direct result of ZIP7-mediated zinc release from intracellular stores. These data reveal the role of ZIP7-mediated zinc release from intracellular stores in driving major pathways, such as MAPK, mTOR and PI3K-AKT, involved in providing cell survival and proliferation and often over activated in cancer.

  3. Decitabine and 5-azacitidine both alleviate LPS induced ARDS through anti-inflammatory/antioxidant activity and protection of glycocalyx and inhibition of MAPK pathways in mice.

    PubMed

    Huang, Xiao; Kong, Guiqing; Li, Yan; Zhu, Weiwei; Xu, Haixiao; Zhang, Xiaohua; Li, Jiankui; Wang, Lipeng; Zhang, Zhongwen; Wu, Yaru; Liu, Xiangyong; Wang, Xiaozhi

    2016-12-01

    Decitabine (5-aza-2'-deoxycytidine, DAC) and 5-azacitidine (Aza), an inhibitor of DNA methyltransferases, possess a wide range of anti-metabolic and anti-cancer activities. This study examined the effects of DAC and Aza on inflammatory and oxidative injuries, as well as on glycocalyx and MAPK signaling pathways, in a LPS-stimulated ARDS mouse model. Results of ELISA revealed that DAC and Aza significantly inhibited the production of TNF-α and IL-1β and prevented LPS-induced elevation of myeloperoxidase and malondialdehyde levels in serum. The W/D ratio of lung and histopathologic examination with hematoxylin and eosin staining showed that DAC and Aza pretreatment substantially improved lung tissue injury. DAC and Aza reduced the level of glycocalyx degradation products (e.g., heparan sulfate and haluronic acid) and protected glycocalyx integrity. Western blot assay demonstrated that DAC and Aza both significantly suppressed LPS-induced activation of the MAPK signaling pathways by blocking the phosphorylation of JNK, ERK and P38 in lung tissues. Bisulfite sequencing PCR and real time-PCR showed that DAC reversed the RASSF1A promoter hypermethylation and furthermore elevated the expression of RASSF1A, which is a tumor suppressor that regulates MAPK signaling pathway. These results suggested that DAC inhibited the MAPK signaling pathway in LPS-induced ARDS mice might via demethylation in RASSF1A promoter region and by restoring its expression. This study highlighted the close relationship between DNA methylation and the development and progression of ARDS.

  4. Strength of ERK1/2 MAPK Activation Determines Its Effect on Myelin and Axonal Integrity in the Adult CNS

    PubMed Central

    Ishii, Akihiro; Furusho, Miki; Dupree, Jeffrey L

    2016-01-01

    Myelin growth is a tightly regulated process driven by multiple signals. ERK1/2-MAPK signaling is an important regulator of myelin thickness. Because, in demyelinating diseases, the myelin formed during remyelination fails to achieve normal thickness, increasing ERK1/2 activity in oligodendrocytes is of obvious therapeutic potential for promoting efficient remyelination. However, other studies have suggested that increased levels of ERK1/2 activity could, in fact, have detrimental effects on myelinating cells. Because the strength, duration, or timing of ERK1/2 activation may alter the biological outcomes of cellular responses markedly, here, we investigated the effect of modulating ERK1/2 activity in myelinating cells using transgenic mouse lines in which ERK1/2 activation was upregulated conditionally in a graded manner. We found enhanced myelin gene expression and myelin growth in the adult CNS at both moderate and hyperactivated levels of ERK1/2 when upregulation commenced during developmental myelination or was induced later during adulthood in quiescent preexisting oligodendrocytes, after active myelination is largely terminated. However, a late onset of demyelination and axonal degeneration occurred at hyperelevated, but not moderately elevated, levels regardless of the timing of the upregulation. Similarly, myelin and axonal pathology occurred with elevated ERK1/2 activity in Schwann cells. We conclude that a fine tuning of ERK1/2 signaling strength is critically important for normal oligodendrocyte and Schwann cell function and that disturbance of this balance has negative consequences for myelin and axonal integrity in the long term. Therefore, therapeutic modulation of ERK1/2 activity in demyelinating disease or peripheral neuropathies must be approached with caution. SIGNIFICANCE STATEMENT ERK1/2-MAPK activation in oligodendrocytes and Schwann cells is an important signal for promoting myelin growth during developmental myelination. Here, we show that

  5. Fisetin induces apoptosis and endoplasmic reticulum stress in human non-small cell lung cancer through inhibition of the MAPK signaling pathway.

    PubMed

    Kang, Kyoung Ah; Piao, Mei Jing; Madduma Hewage, Susara Ruwan Kumara; Ryu, Yea Seong; Oh, Min Chang; Kwon, Taeg Kyu; Chae, Sungwook; Hyun, Jin Won

    2016-07-01

    Fisetin (3,3',4',7-tetrahydroxyflavone), a dietary flavonoid compound, is currently being investigated for its anticancer effect in various cancer models, including lung cancer. Recent studies show that fisetin induces cell growth inhibition and apoptosis in the human non-small cell lung cancer line NCI-H460. In this study, we investigated whether fisetin can induce endoplasmic reticulum (ER) stress-mediated apoptosis in NCI-H460 cells. Fisetin induced mitochondrial reactive oxygen species (ROS) and characteristic signs of ER stress: ER staining; mitochondrial Ca(2+) overload; expression of ER stress-related proteins; glucose-regulated protein (GRP)-78, phosphorylation of protein kinase RNA (PKR)-like endoplasmic reticulum kinase (PERK) and phosphorylation of eukaryotic initiation factor-2 α subunit; cleavage of activating transcription factor-6; phosphorylation of inositol-requiring kinase-1 and splicing of X-box transcription factor-1; induction of C/EBP homologous protein and cleaved caspase-12. siRNA-mediated knockdown of CHOP and ATF-6 attenuated fisetin-induced apoptotic cell death. In addition, fisetin induced phosphorylation of ERK, JNK, and p38 MAPK. Moreover, silencing of the MAPK signaling pathway prevented apoptotic cell death. In summary, our results indicate that, in NCI-H460 cells, fisetin induces apoptosis and ER stress that is mediated by induction of the MAPK signaling pathway.

  6. The Activation of ERK1/2 and JNK MAPK Signaling by Insulin/IGF-1 Is Responsible for the Development of Colon Cancer with Type 2 Diabetes Mellitus.

    PubMed

    Teng, Jia-An; Wu, San-Gang; Chen, Jia-Xin; Li, Qiang; Peng, Fang; Zhu, Zhou; Qin, Jian; He, Zhen-Yu

    2016-01-01

    Previous studies showed that type 2 diabetes mellitus (T2DM) is linked to increased risk of developing colon cancer. Insulin and insulin-like growth factor 1 (IGF-1) are increased in patients with T2DM. The increased insulin and IGF-1 may be responsible for the developing of colon cancer. In this study, we investigated the effects and mechanisms of insulin and IGF-1 in colon cancer development in vitro and in vivo. Insulin and IGF-1 alone or together elevated proliferation and reduced apoptosis in colon cancer MC38 cells. Meanwhile, insulin and IGF-1 promoted the phosphorylation of extracellular-signal regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK). Treatment with ERK1/2 or JNK inhibitor in the presence of insulin and IGF-1 significantly decreased B-cell lymphoma 2 (Bcl-2) and increased Bcl-2-associated X protein (Bax) expression and finally increased apoptosis and inhibited the proliferation. Accelerative colon tumor growth was found in a mouse model of T2DM with db/db mice which got high level of endogenous insulin and IGF-1. Furthermore, the inhibition of ERK1/2 or JNK suppressed the development of colon tumor in vivo. These results suggest that the activation of ERK1/2 and JNK signaling by insulin and IGF-1, at least in part, is responsible for the development of colon cancer with T2DM.

  7. FGF signaling via MAPK is required early and improves Activin A-induced definitive endoderm formation from human embryonic stem cells

    SciTech Connect

    Sui, Lina; Mfopou, Josue K.; Geens, Mieke; Sermon, Karen; Bouwens, Luc

    2012-09-28

    Highlights: Black-Right-Pointing-Pointer Deep study the FGF signaling role during DE specification in the context of hESCs. Black-Right-Pointing-Pointer DE differentiation from hESCs has an early dependence on FGF signaling. Black-Right-Pointing-Pointer A serum-free DE protocol is developed based on the findings. Black-Right-Pointing-Pointer The DE cells showed potential to differentiate into pancreatic progenitor cells. -- Abstract: Considering their unlimited proliferation and pluripotency properties, human embryonic stem cells (hESCs) constitute a promising resource applicable for cell replacement therapy. To facilitate this clinical translation, it is critical to study and understand the early stage of hESCs differentiation wherein germ layers are defined. In this study, we examined the role of FGF signaling in Activin A-induced definitive endoderm (DE) differentiation in the absence of supplemented animal serum. We found that activated FGF/MAPK signaling is required at the early time point of Activin A-induced DE formation. In addition, FGF activation increased the number of DE cells compared to Activin A alone. These DE cells could further differentiate into PDX1 and NKX6.1 positive pancreatic progenitors in vitro. We conclude that Activin A combined with FGF/MAPK signaling efficiently induce DE cells in the absence of serum. These findings improve our understanding of human endoderm formation, and constitute a step forward in the generation of clinical grade hESCs progenies for cell therapy.

  8. Tanreqing Injection Attenuates Lipopolysaccharide-Induced Airway Inflammation through MAPK/NF-κB Signaling Pathways in Rats Model

    PubMed Central

    Liu, Wei; Jiang, Hong-li; Cai, Lin-li; Yan, Min; Dong, Shou-jin; Mao, Bing

    2016-01-01

    Background. Tanreqing injection (TRQ) is a commonly used herbal patent medicine for treating inflammatory airway diseases in view of its outstanding anti-inflammatory properties. In this study, we explored the signaling pathways involved in contributions of TRQ to LPS-induced airway inflammation in rats. Methods/Design. Adult male Sprague Dawley (SD) rats randomly divided into different groups received intratracheal instillation of LPS and/or intraperitoneal injection of TRQ. Bronchoalveolar Lavage Fluid (BALF) and lung samples were collected at 24 h, 48 h, and 96 h after TRQ administration. Protein and mRNA levels of tumor necrosis factor- (TNF-) α, Interleukin- (IL-) 1β, IL-6, and IL-8 in BALF and lung homogenate were observed by ELISA and real-time PCR, respectively. Lung sections were stained for p38 MAPK and NF-κB detection by immunohistochemistry. Phospho-p38 MAPK, phosphor-extracellular signal-regulated kinases ERK1/2, phospho-SAPK/JNK, phospho-NF-κB p65, phospho-IKKα/β, and phospho-IκB-α were measured by western blot analysis. Results. The results showed that TRQ significantly counteracted LPS-stimulated release of TNF-α, IL-1β, IL-6, and IL-8, attenuated cells influx in BALF, mitigated mucus hypersecretion, suppressed phosphorylation of NF-κB p65, IκB-α, ΙKKα/β, ERK1/2, JNK, and p38 MAPK, and inhibited p38 MAPK and NF-κB p65 expression in rat lungs. Conclusions. Results of the current research indicate that TRQ possesses potent exhibitory effects in LPS-induced airway inflammation by, at least partially, suppressing the MAPKs and NF-κB signaling pathways, in a general dose-dependent manner. PMID:27366191

  9. p27kip1 controls H-Ras/MAPK activation and cell cycle entry via modulation of MT stability

    PubMed Central

    Fabris, Linda; Berton, Stefania; Pellizzari, Ilenia; Segatto, Ilenia; D’Andrea, Sara; Armenia, Joshua; Bomben, Riccardo; Schiappacassi, Monica; Gattei, Valter; Philips, Mark R.; Vecchione, Andrea; Belletti, Barbara; Baldassarre, Gustavo

    2015-01-01

    The cyclin-dependent kinase (CDK) inhibitor p27kip1 is a critical regulator of the G1/S-phase transition of the cell cycle and also regulates microtubule (MT) stability. This latter function is exerted by modulating the activity of stathmin, an MT-destabilizing protein, and by direct binding to MTs. We recently demonstrated that increased proliferation in p27kip1-null mice is reverted by concomitant deletion of stathmin in p27kip1/stathmin double-KO mice, suggesting that a CDK-independent function of p27kip1 contributes to the control of cell proliferation. Whether the regulation of MT stability by p27kip1 impinges on signaling pathway activation and contributes to the decision to enter the cell cycle is largely unknown. Here, we report that faster cell cycle entry of p27kip1-null cells was impaired by the concomitant deletion of stathmin. Using gene expression profiling coupled with bioinformatic analyses, we show that p27kip1 and stathmin conjunctly control activation of the MAPK pathway. From a molecular point of view, we observed that p27kip1, by controlling MT stability, impinges on H-Ras trafficking and ubiquitination levels, eventually restraining its full activation. Our study identifies a regulatory axis controlling the G1/S-phase transition, relying on the regulation of MT stability by p27kip1 and finely controlling the spatiotemporal activation of the Ras-MAPK signaling pathway. PMID:26512117

  10. p27kip1 controls H-Ras/MAPK activation and cell cycle entry via modulation of MT stability.

    PubMed

    Fabris, Linda; Berton, Stefania; Pellizzari, Ilenia; Segatto, Ilenia; D'Andrea, Sara; Armenia, Joshua; Bomben, Riccardo; Schiappacassi, Monica; Gattei, Valter; Philips, Mark R; Vecchione, Andrea; Belletti, Barbara; Baldassarre, Gustavo

    2015-11-10

    The cyclin-dependent kinase (CDK) inhibitor p27(kip1) is a critical regulator of the G1/S-phase transition of the cell cycle and also regulates microtubule (MT) stability. This latter function is exerted by modulating the activity of stathmin, an MT-destabilizing protein, and by direct binding to MTs. We recently demonstrated that increased proliferation in p27(kip1)-null mice is reverted by concomitant deletion of stathmin in p27(kip1)/stathmin double-KO mice, suggesting that a CDK-independent function of p27(kip1) contributes to the control of cell proliferation. Whether the regulation of MT stability by p27(kip1) impinges on signaling pathway activation and contributes to the decision to enter the cell cycle is largely unknown. Here, we report that faster cell cycle entry of p27(kip1)-null cells was impaired by the concomitant deletion of stathmin. Using gene expression profiling coupled with bioinformatic analyses, we show that p27(kip1) and stathmin conjunctly control activation of the MAPK pathway. From a molecular point of view, we observed that p27(kip1), by controlling MT stability, impinges on H-Ras trafficking and ubiquitination levels, eventually restraining its full activation. Our study identifies a regulatory axis controlling the G1/S-phase transition, relying on the regulation of MT stability by p27(kip1) and finely controlling the spatiotemporal activation of the Ras-MAPK signaling pathway.

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

    PubMed Central

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

    2016-01-01

    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. PMID:27271793

  12. MicroRNA-7 inhibits cell proliferation, migration and invasion in human non-small cell lung cancer cells by targeting FAK through ERK/MAPK signaling pathway

    PubMed Central

    Shi, Yu-Jia; Chen, Yi; Sun, Yun; Zhang, Qian; Song, Lei; Peng, Li-Ping

    2016-01-01

    Objective To investigate the effects of microRNA-7 (miR-7) on the proliferation, migration and invasion of non-small cell lung cancer NSCLC) cells by targeting FAK through ERK/MAPK signaling pathway. Methods NSCLC tissues and adjacent normal tissues were obtained from 160 NSCLC patients after operation. NSCLC cell lines (A549, H1299 and H1355) and a normal human fetal lung fibroblast cell line (MRC-5) were obtained. NSCLC cells were assigned into miR-7 inhibitors, miR-7 mimics, blank, miR-7 mimics control, miR-7 inhibitors control, FAK siRNA and miR-7 inhibitors + FAK siRNA groups. The expressions of miR-7 and FAK mRNA in tissues and cell lines were detected by qRT-PCR and Western-Blotting. Cell proliferation, migration and invasion were detected by MTT assay, wound scratch assay and Transwell assay. Results Compared with adjacent normal tissues, miR-7 expression was down-regulated, but the mRNA and protein expressions of FAK, ERK and MAPK were up-regulated. Compared with the blank and mimics control groups, miR-7 significantly increased but FAK, ERK and MAPK expressions decreased in miR-7 mimics and FAK siRNA groups. Cell proliferation, migration and invasion were inhibited in the miR-7 mimics and FAK siRNA groups, while opposite regarding miR-7 inhibitors group. Conclusion The miR-7 can inhibit the activation of ERK/MAPK signaling pathway by down-regulating FAK expression, thereby suppressing the proliferation, migration and invasion of NSCLC cells. The miR-7 and its target gene FAK may be novel targets for the diagnosis and treatment of NSCLC. PMID:27764812

  13. 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.

  14. Regulation of SREBPs by Sphingomyelin in Adipocytes via a Caveolin and Ras-ERK-MAPK-CREB Signaling Pathway

    PubMed Central

    Makdissy, Nehman; Popa, Iuliana; Younsi, Mohamed; Valet, Philippe; Brunaud, Laurent; Ziegler, Olivier; Quilliot, Didier

    2015-01-01

    Sterol response element binding protein (SREBP) is a key transcription factor in insulin and glucose metabolism. We previously demonstrated that elevated levels of membrane sphingomyelin (SM) were related to peroxisome proliferator–activated receptor-γ (PPARγ), which is a known target gene of SREBP-1 in adipocytes. However, the role of SM in SREBP expression in adipocytes remains unknown. In human abdominal adipose tissue from obese women with various concentrations of fasting plasma insulin, SREBP-1 proteins decreased in parallel with increases in membrane SM levels. An inverse correlation was found between the membrane SM content and the levels of SREBP-1c/ERK/Ras/PPARγ/CREB proteins. For the first time, we demonstrate the effects of SM and its signaling pathway in 3T3-F442A adipocytes. These cells were enriched or unenriched with SM in a range of concentrations similar to those observed in obese subjects by adding exogenous natural SMs (having different acyl chain lengths) or by inhibiting neutral sphingomyelinase. SM accumulated in caveolae of the plasma membrane within 24 h and then in the intracellular space. SM enrichment decreased SREBP-1 through the inhibition of extracellular signal-regulated protein kinase (ERK) but not JNK or p38 mitogen-activated protein kinase (MAPK). Ras/Raf-1/MEK1/2 and KSR proteins, which are upstream mediators of ERK, were down-regulated, whereas SREBP-2/caveolin and cholesterol were up-regulated. In SM-unmodulated adipocytes treated with DL-1-Phenyl-2-Palmitoylamino-3-morpholino-1-propanol (PPMP), where the ceramide level increased, the expression levels of SREBPs and ERK were modulated in an opposite direction relative to the SM-enriched cells. SM inhibited the insulin-induced expression of SREBP-1. Rosiglitazone, which is an anti-diabetic agent and potent activator of PPARγ, reversed the effects of SM on SREBP-1, PPARγ and CREB. Taken together, these findings provide novel insights indicating that excess membrane SM

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

    SciTech Connect

    Cheon, Soyoung; Song, Seok Bean; Jung, Minkyung; Park, Yoorim; Bang, Jung-Wook; Kim, Tae Sung; Park, Hyunjeong; Kim, Cherl-hyun; Yang, Yool-hee; Bang, Sa Ik; Cho, Daeho

    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 mRNA 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.

  16. Astaxanthin Inhibits Acetaldehyde-Induced Cytotoxicity in SH-SY5Y Cells by Modulating Akt/CREB and p38MAPK/ERK Signaling Pathways

    PubMed Central

    Yan, Tingting; Zhao, Yan; Zhang, Xia; Lin, Xiaotong

    2016-01-01

    Excessive alcohol consumption can lead to brain tissue damage and cognitive dysfunction. Acetaldehyde, the most toxic metabolite of ethanol, mediates the brain tissue damage and cognitive dysfunction induced by chronic excessive alcohol consumption. In this study, the effect of astaxanthin, a marine bioactive compound, on acetaldehyde-induced cytotoxicity was investigated in SH-SY5Y cells. It was found that astaxanthin protected cells from apoptosis by ameliorating the effect of acetaldehyde on the expression of Bcl-2 family proteins, preventing the reduction of anti-apoptotic protein Bcl-2 and the increase of pro-apoptotic protein Bak induced by acetaldehyde. Further analyses showed that astaxanthin treatment inhibited acetaldehyde-induced reduction of the levels of activated Akt and cyclic AMP-responsive element binding protein (CREB). Astaxanthin treatment also prevented acetaldehyde-induced increase of the level of activated p38 mitogen-activated protein kinase (MAPK) and decrease of the level of activated extracellular signal-regulated kinases (ERKs). Activation of Akt/CREB pathway promotes cell survival and is involved in the upregulation of Bcl-2 gene. P38MAPK plays a critical role in apoptotic events while ERKs mediates the inhibition of apoptosis. Thus, astaxanthin may inhibit acetaldehyde-induced apoptosis through promoting the activation of Akt/CREB and ERKs and blocking the activation of p38MAPK. In addition, astaxanthin treatment suppressed the oxidative stress induced by acetaldehyde and restored the antioxidative capacity of SH-SY5Y cells. Therefore, astaxanthin may protect cells against acetaldehyde-induced cytotoxicity through maintaining redox balance and modulating apoptotic and survival signals. The results suggest that astaxanthin treatment may be beneficial for preventing neurotoxicity associated with acetaldehyde and excessive alcohol consumption. PMID:26978376

  17. Astaxanthin Inhibits Acetaldehyde-Induced Cytotoxicity in SH-SY5Y Cells by Modulating Akt/CREB and p38MAPK/ERK Signaling Pathways.

    PubMed

    Yan, Tingting; Zhao, Yan; Zhang, Xia; Lin, Xiaotong

    2016-03-10

    Excessive alcohol consumption can lead to brain tissue damage and cognitive dysfunction. Acetaldehyde, the most toxic metabolite of ethanol, mediates the brain tissue damage and cognitive dysfunction induced by chronic excessive alcohol consumption. In this study, the effect of astaxanthin, a marine bioactive compound, on acetaldehyde-induced cytotoxicity was investigated in SH-SY5Y cells. It was found that astaxanthin protected cells from apoptosis by ameliorating the effect of acetaldehyde on the expression of Bcl-2 family proteins, preventing the reduction of anti-apoptotic protein Bcl-2 and the increase of pro-apoptotic protein Bak induced by acetaldehyde. Further analyses showed that astaxanthin treatment inhibited acetaldehyde-induced reduction of the levels of activated Akt and cyclic AMP-responsive element binding protein (CREB). Astaxanthin treatment also prevented acetaldehyde-induced increase of the level of activated p38 mitogen-activated protein kinase (MAPK) and decrease of the level of activated extracellular signal-regulated kinases (ERKs). Activation of Akt/CREB pathway promotes cell survival and is involved in the upregulation of Bcl-2 gene. P38MAPK plays a critical role in apoptotic events while ERKs mediates the inhibition of apoptosis. Thus, astaxanthin may inhibit acetaldehyde-induced apoptosis through promoting the activation of Akt/CREB and ERKs and blocking the activation of p38MAPK. In addition, astaxanthin treatment suppressed the oxidative stress induced by acetaldehyde and restored the antioxidative capacity of SH-SY5Y cells. Therefore, astaxanthin may protect cells against acetaldehyde-induced cytotoxicity through maintaining redox balance and modulating apoptotic and survival signals. The results suggest that astaxanthin treatment may be beneficial for preventing neurotoxicity associated with acetaldehyde and excessive alcohol consumption.

  18. Altered ERK/MAPK signaling in the hippocampus of the mrsk2_KO mouse model of Coffin-Lowry syndrome.

    PubMed

    Schneider, Anne; Mehmood, Tahir; Pannetier, Solange; Hanauer, André

    2011-11-01

    Coffin-Lowry syndrome is a syndromic form of mental retardation caused by mutations of the Rps6ka3 gene encoding ribosomal s6 kinase (RSK)2. RSK2 belongs to a family containing four members in mammals: RSK1-4. RSKs are serine/threonine kinases and cytosolic substrates of extracellular signal-regulated kinase (ERK) in the Ras/MAPK signaling pathway. RSK2 is highly expressed in the hippocampus, and mrsk2_KO mice display spatial learning and memory impairment. In the present study, we provide evidence of abnormally increased phosphorylation of ERK1/2 in the hippocampus of mrsk2_KO mice. Further studies based on cultured hippocampal neurons revealed that glutamate activates ERK1/2 and RSKs, and confirmed a stronger activation of ERK1/2 in mrsk2_KO neurons than in WT cells. We, thus, provide further evidence that RSK2 exerts a feedback inhibitory effect on the ERK1/2 pathway. We also observed a transient sequestration of P-ERK1/2 in the cytoplasm upon glutamate stimulation. In addition, the transcription factors cAMP response element binding and Ets LiKe gene1 show over-activation in RSK2-deficient neurons. Finally, c-Fos, Zif268 and Arc were significantly over-expressed in mrsk2_KO neurons upon glutamate stimulation. Importantly, the increased phosphorylation of other RSK family members observed in mutant neurons was unable to compensate for RSK2 deficiency. This aberrant ERK1/2 signaling can influence various neuronal functions, and thus play a significant role in cognitive dysfunction in mrsk2_KO mice and in the Coffin-Lowry syndrome.

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

    ERIC Educational Resources Information Center

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

    2005-01-01

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

  20. Adiponectin stimulates human osteoblasts proliferation and differentiation via the MAPK signaling pathway

    SciTech Connect

    Luo Xianghang; Guo Lijuan; Yuan Lingqing; Xie Hui; Zhou Houde; Wu Xianping; Liao Eryuan . E-mail: eyliao1207@21cn.com

    2005-09-10

    Adipocytes can highly and specifically express adiponectin, and the adiponectin receptor (AdipoR) has been detected in bone-forming cells. The present study was undertaken to investigate the action of adiponectin on osteoblast proliferation and differentiation. AdipoR1 protein was detected in human osteoblasts. Adiponectin promoted osteoblast proliferation and resulted in a dose- and time-dependent increase in alkaline phosphatase (ALP) activity, osteocalcin and type I collagen production, and an increase in mineralized matrix. Suppression of AdipoR1 with small-interfering RNA (siRNA) abolished the adiponectin-induced cell proliferation and ALP expression. Adiponectin induces activation of p38 mitogen-activated protein kinase (MAPK) and c-jun N-terminal Kinase (JNK), but not ERK1/2 in osteoblasts, and these effects were blocked by suppression of AdipoR1 with siRNA. Furthermore, pretreatment of osteoblasts with the JNK inhibitor SP600125 abolished the adiponectin-induced cell proliferation. p38 inhibitor SB203580 blocked the adiponectin-induced ALP activity. These data indicate that adiponectin induces human osteoblast proliferation and differentiation, and the proliferation response is mediated by the AdipoR/JNK pathway, while the differentiation response is mediated via the AdipoR/p38 pathway. These findings suggest that osteoblasts are the direct targets of adiponectin.

  1. Mammary gland specific expression of Brk/PTK6 promotes delayed involution and tumor formation associated with activation of p38 MAPK

    PubMed Central

    2011-01-01

    Introduction Protein tyrosine kinases (PTKs) are frequently overexpressed and/or activated in human malignancies, and regulate cancer cell proliferation, cellular survival, and migration. As such, they have become promising molecular targets for new therapies. The non-receptor PTK termed breast tumor kinase (Brk/PTK6) is overexpressed in approximately 86% of human breast tumors. The role of Brk in breast pathology is unclear. Methods We expressed a WAP-driven Brk/PTK6 transgene in FVB/n mice, and analyzed mammary glands from wild-type (wt) and transgenic mice after forced weaning. Western blotting and immunohistochemistry (IHC) studies were conducted to visualize markers of mammary gland involution, cell proliferation and apoptosis, as well as Brk, STAT3, and activated p38 mitogen-activated protein kinase (MAPK) in mammary tissues and tumors from WAP-Brk mice. Human (HMEC) or mouse (HC11) mammary epithelial cells were stably or transiently transfected with Brk cDNA to assay p38 MAPK signaling and cell survival in suspension or in response to chemotherapeutic agents. Results Brk-transgenic dams exhibited delayed mammary gland involution and aged mice developed infrequent tumors with reduced latency relative to wt mice. Consistent with delayed involution, mammary glands of transgenic animals displayed decreased STAT3 phosphorylation, a marker of early-stage involution. Notably, p38 MAPK, a pro-survival signaling mediator downstream of Brk, was activated in mammary glands of Brk transgenic relative to wt mice. Brk-dependent signaling to p38 MAPK was recapitulated by Brk overexpression in the HC11 murine mammary epithelial cell (MEC) line and human MEC, while Brk knock-down in breast cancer cells blocked EGF-stimulated p38 signaling. Additionally, human or mouse MECs expressing Brk exhibited increased anchorage-independent survival and resistance to doxorubicin. Finally, breast tumor biopsies were subjected to IHC analysis for co-expression of Brk and phospho-p38 MAPK

  2. Cyclooxygenase-2 induced β1-integrin expression in NSCLC and promoted cell invasion via the EP1/MAPK/E2F-1/FoxC2 signal pathway

    PubMed Central

    Pan, Jinshun; Yang, Qinyi; Shao, Jiaofang; Zhang, Li; Ma, Juan; Wang, Yipin; Jiang, Bing-Hua; Leng, Jing; Bai, Xiaoming

    2016-01-01

    Cyclooxygenase-2 (COX-2) has been implicated in cell invasion in non-small-cell lung cancer (NSCLC). However, the mechanism is unclear. The present study investigated the effect of COX-2 on β1-integrin expression and cell invasion in NSCLC. COX-2 and β1-integrin were co-expressed in NSCLC tissues. COX-2 overexpression or Prostaglandin E2 (PGE2) treatment increased β1-integrin expression in NSCLC cell lines. β1-integrin silencing suppressed COX-2-mediated tumour growth and cancer cell invasion in vivo and in vitro. Prostaglandin E Receptor EP1 transfection or treatment with EP1 agonist mimicked the effect of PGE2 treatment. EP1 siRNA blocked PGE2-mediated β1-integrin expression. EP1 agonist treatment promoted Erk1/2, p38 phosphorylation and E2F-1 expression. MEK1/2 and p38 inhibitors suppressed EP1-mediated β1-integrin expression. E2F-1 silencing suppressed EP1-mediated FoxC2 and β1-integrin upregulation. ChIP and Luciferase Reporter assays identified that EP1 agonist treatment induced E2F-1 binding to FoxC2 promotor directly and improved FoxC2 transcription. FoxC2 siRNA suppressed β1-integrin expression and EP1-mediated cell invasion. Immunohistochemistry showed E2F-1, FoxC2, and EP1R were all highly expressed in the NSCLC cases. This study suggested that COX-2 upregulates β1-integrin expression and cell invasion in NSCLC by activating the MAPK/E2F-1 signalling pathway. Targeting the COX-2/EP1/PKC/MAPK/E2F-1/FoxC2/β1-integrin pathway might represent a new therapeutic strategy for the prevention and treatment of this cancer. PMID:27654511

  3. Histamine H3-receptor signaling in cardiac sympathetic nerves: Identification of a novel MAPK-PLA2-COX-PGE2-EP3R pathway.

    PubMed

    Levi, Roberto; Seyedi, Nahid; Schaefer, Ulrich; Estephan, Rima; Mackins, Christina J; Tyler, Eleanor; Silver, Randi B

    2007-04-15

    We hypothesized that the histamine H(3)-receptor (H(3)R)-mediated attenuation of norepinephrine (NE) exocytosis from cardiac sympathetic nerves results not only from a Galpha(i)-mediated inhibition of the adenylyl cyclase-cAMP-PKA pathway, but also from a Gbetagamma(i)-mediated activation of the MAPK-PLA(2) cascade, culminating in the formation of an arachidonate metabolite with anti-exocytotic characteristics (e.g., PGE(2)). We report that in Langendorff-perfused guinea-pig hearts and isolated sympathetic nerve endings (cardiac synaptosomes), H(3)R-mediated attenuation of K(+)-induced NE exocytosis was prevented by MAPK and PLA(2) inhibitors, and by cyclooxygenase and EP(3)-receptor (EP(3)R) antagonists. Moreover, H(3)R activation resulted in MAPK phosphorylation in H(3)R-transfected SH-SY5Y neuroblastoma cells, and in PLA(2) activation and PGE(2) production in cardiac synaptosomes; H(3)R-induced MAPK phosphorylation was prevented by an anti-betagamma peptide. Synergism between H(3)R and EP(3)R agonists (i.e., imetit and sulprostone, respectively) suggested that PGE(2) may be a downstream effector of the anti-exocytotic effect of H(3)R activation. Furthermore, the anti-exocytotic effect of imetit and sulprostone was potentiated by the N-type Ca(2+)-channel antagonist omega-conotoxin GVIA, and prevented by an anti-Gbetagamma peptide. Our findings imply that an EP(3)R Gbetagamma(i)-induced decrease in Ca(2+) influx through N-type Ca(2+)-channels is involved in the PGE(2)/EP(3)R-mediated attenuation of NE exocytosis elicited by H(3)R activation. Conceivably, activation of the Gbetagamma(i) subunit of H(3)R and EP(3)R may also inhibit Ca(2+) entry directly, independent of MAPK intervention. As heart failure, myocardial ischemia and arrhythmic dysfunction are associated with excessive local NE release, attenuation of NE release by H(3)R activation is cardioprotective. Accordingly, this novel H(3)R signaling pathway may ultimately bear therapeutic significance in hyper

  4. Preclinical efficacy of a RAF inhibitor that evades paradoxical MAPK pathway activation in protein kinase BRAF-mutant lung cancer.

    PubMed

    Okimoto, Ross A; Lin, Luping; Olivas, Victor; Chan, Elton; Markegard, Evan; Rymar, Andrey; Neel, Dana; Chen, Xiao; Hemmati, Golzar; Bollag, Gideon; Bivona, Trever G

    2016-11-22

    Oncogenic activation of protein kinase BRAF drives tumor growth by promoting mitogen-activated protein kinase (MAPK) pathway signaling. Because oncogenic mutations in BRAF occur in ∼2-7% of lung adenocarcinoma (LA), BRAF-mutant LA is the most frequent cause of BRAF-mutant cancer mortality worldwide. Whereas most tumor types harbor predominantly the BRAF(V600E)-mutant allele, the spectrum of BRAF mutations in LA includes BRAF(V600E) (∼60% of cases) and non-V600E mutant alleles (∼40% of cases) such as BRAF(G469A) and BRAF(G466V) The presence of BRAF(V600E) in LA has prompted clinical trials testing selective BRAF inhibitors such as vemurafenib in BRAF(V600E)-mutant patients. Despite promising clinical efficacy, both innate and acquired resistance often result from reactivation of MAPK pathway signaling, thus limiting durable responses to the current BRAF inhibitors. Further, the optimal therapeutic strategy to block non-V600E BRAF-mutant LA remains unclear. Here, we report the efficacy of the Raf proto-oncogene serine/threonine protein kinase (RAF) inhibitor, PLX8394, that evades MAPK pathway reactivation in BRAF-mutant LA models. We show that PLX8394 treatment is effective in both BRAF(V600E) and certain non-V600 LA models, in vitro and in vivo. PLX8394 was effective against treatment-naive BRAF-mutant LAs and those with acquired vemurafenib resistance caused by an alternatively spliced, truncated BRAF(V600E) that promotes vemurafenib-insensitive MAPK pathway signaling. We further show that acquired PLX8394 resistance occurs via EGFR-mediated RAS-mTOR signaling and is prevented by upfront combination therapy with PLX8394 and either an EGFR or mTOR inhibitor. Our study provides a biological rationale and potential polytherapy strategy to aid the deployment of PLX8394 in lung cancer patients.

  5. The crosstalk between α-irradiated Beas-2B cells and its bystander U937 cells through MAPK and NF-κB signaling pathways.

    PubMed

    Fu, Jiamei; Yuan, Dexiao; Xiao, Linlin; Tu, Wenzhi; Dong, Chen; Liu, Weili; Shao, Chunlin

    2016-01-01

    Although accumulated evidence suggests that α-particle irradiation induced bystander effect may relevant to lung injury and cancer risk assessment, the exact mechanisms are not yet elucidated. In the present study, a cell co-culture system was used to investigate the interaction between α-particle irradiated human bronchial epithelial cells (Beas-2B) and its bystander macrophage U937 cells. It was found that the cell co-culture amplified the detrimental effects of α-irradiation including cell viability decrease and apoptosis promotion on both irradiated cells and bystander cells in a feedback loop which was closely relevant to the activation of MAPK and NF-κB pathways in the bystander U937 cells. When these two pathways in U937 cells were disturbed by special pharmacological inhibitors before cell co-culture, it was found that a NF-κB inhibitor of BAY 11-7082 further enhanced the proliferation inhibition and apoptosis induction in bystander U937 cells, but MAPK inhibitors of SP600125 and SB203580 protected cells from viability loss and apoptosis and U0126 presented more beneficial effect on cell protection. For α-irradiated epithelial cells, the activation of NF-κB and MAPK pathways in U937 cells participated in detrimental cellular responses since the above inhibitors could largely attenuate cell viability loss and apoptosis of irradiated cells. Our results demonstrated that there are bilateral bystander responses between irradiated lung epithelial cells and macrophages through MAPK and NF-κB signaling pathways, which accounts for the enhancement of α-irradiation induced damage.

  6. The Ethanol Extract of Fructus trichosanthis Promotes Fetal Hemoglobin Production via p38 MAPK Activation and ERK Inactivation in K562 Cells

    PubMed Central

    Li, Hui; Ko, Chun Hay; Tsang, Suk Ying; Leung, Ping Chung; Fung, Ming Chui; Fung, Kwok Pui

    2011-01-01

    Pharmacological stimulation of fetal hemoglobin (HbF) expression may be a promising approach for the treatment of beta-thalassemia. In this study, the effects of Fructus trichosanthis (FT) were investigated in human erythroleukemic K562 cells for their gamma-globin mRNA and HbF-induction activities. The role of signaling pathways, including extracellular regulated protein kinase (ERK) and p38 mitogen-activated protein kinase (MAPK), was also investigated. It was found that the ethanol extract of FT significantly increased gamma-globin mRNA and HbF levels, determined by real-time reverse transcription polymerase chain reaction and enzyme linked immunosorbent assay, respectively, in dose- and time-dependent manner. Total Hb (THb) levels were also elevated in the concentrations without cytotoxicity (<80 μg mL−1). Pre-treatment with p38 MAPK inhibitor SB203580 blocked the stimulatory effects of FT extract in total and HbF induction. In contrast, no change in HbF was observed when treated with ERK inhibitor PD98059. Furthermore, FT ethanol extract activated p38 MAPK and inhibited ERK signaling pathways in K562 cells, as revealed in western blotting analysis. In addition, SB203580 significantly abolished p38 MAPK activation when the cells were treated with FT. In summary, the ethanol extract of FT was found to be a potent inducer of HbF synthesis in K562 cells. The present data delineated the role of ERK and p38 MAPK signaling as molecular targets for pharmacologic stimulation of HbF production upon FT treatment. PMID:21876711

  7. Perfluorocarbon reduces cell damage from blast injury by inhibiting signal paths of NF-κB, MAPK and Bcl-2/Bax signaling pathway in A549 cells

    PubMed Central

    Li, Huaidong; Li, Chunsun; Yang, Zhen; Li, Yanqin; She, Danyang; Cao, Lu; Wang, Wenjie; Liu, Changlin; Chen, Liangan

    2017-01-01

    Background and objective Blast lung injury is a common type of blast injury and has very high mortality. Therefore, research to identify medical therapies for blast injury is important. Perfluorocarbon (PFC) is used to improve gas exchange in diseased lungs and has anti-inflammatory functions in vitro and in vivo. The aim of this study was to determine whether PFC reduces damage to A549 cells caused by blast injury and to elucidate its possible mechanisms of action. Study design and methods A549 alveolar epithelial cells exposed to blast waves were treated with and without PFC. Morphological changes and apoptosis of A549 cells were recorded. PCR and enzyme-linked immunosorbent assay (ELISA) were used to measure the mRNA or protein levels of IL-1β, IL-6 and TNF-α. Malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity levels were detected. Western blot was used to quantify the expression of NF-κB, Bax, Bcl-2, cleaved caspase-3 and MAPK cell signaling proteins. Results A549 cells exposed to blast wave shrank, with less cell-cell contact. The morphological change of A549 cells exposed to blast waves were alleviated by PFC. PFC significantly inhibited the apoptosis of A549 cells exposed to blast waves. IL-1β, IL-6 and TNF-α cytokine and mRNA expression levels were significantly inhibited by PFC. PFC significantly increased MDA levels and decreased SOD activity levels. Further studies indicated that NF-κB, Bax, caspase-3, phospho-p38, phosphor-ERK and phosphor-JNK proteins were also suppressed by PFC. The quantity of Bcl-2 protein was increased by PFC. Conclusion Our research showed that PFC reduced A549 cell damage caused by blast injury. The potential mechanism may be associated with the following signaling pathways: 1) the signaling pathways of NF-κB and MAPK, which inhibit inflammation and reactive oxygen species (ROS); and 2) the signaling pathways of Bcl-2/Bax and caspase-3, which inhibit apoptosis. PMID:28323898

  8. Spatio-temporal dynamics of a cell signal pathway with negative feedbacks: the MAPK/ERK pathway.

    PubMed

    Maya-Bernal, José Luis; Ramírez-Santiago, Guillermo

    2016-03-01

    We studied the spatio-temporal dynamics of a cell signal cascade with negative feedback that quantitatively emulates the regulative process that occurs in the Mitogen Activated Protein Kinase/Extracellular Regulated Kinase (MAPK/ERK) pathway. The model consists of a set of six coupled reaction-diffusion equations that describes the dynamics of the six-module pathway. In the basic module the active form of the protein transmits the signal to the next pathway’s module. As suggested by experiments, the model considers that the fifth module's kinase down-regulates the first and third modules. The feedback parameter is defined as, μ(r)( j)= k(kin)5/k(kin)(j), (j = 1, 3). We analysed the pathway's dynamics for μ(r)( j) = 0.10, 1.0, and 10 in the kinetic regimes: i) saturation of both kinases and phosphatases, ii) saturation of the phosphatases and iii) saturation of the kinases. For a regulated pathway the Total Activated Protein Profiles (TAPPs) as a function of time develop a maximum during the transient stage in the three kinetic regimes. These maxima become higher and their positions shift to longer times downstream. This scenario also applies to the TAPP's regulatory kinase that sums up its inhibitory action to that of the phosphatases leading to a maximum. Nevertheless, when μ(r)(j)= 1.0 , the TAPPs develop two maxima, with the second maximum being almost imperceptible. These results are in qualitative agreement with experimental data obtained from NIH 3T3 mouse fibroblasts. In addition, analyses of the stationary states as a function of position indicate that in the kinetic regime i) which is of physiological interest, signal transduction occurs with a relatively large propagation length for the three values of the regulative parameter. However, for μ(r)(j)= 0.10 , the sixth module concentration profile is transmitted with approximately 45% of its full value. The results obtained for μ(r)(j) = 10 , indicate that the first five concentration profiles are

  9. Oxidized High-Density Lipoprotein Impairs Endothelial Progenitor Cells' Function by Activation of CD36-MAPK-TSP-1 Pathways

    PubMed Central

    Wu, Jianxiang; He, Zhiqing; Gao, Xiang; Wu, Feng; Ding, Ru; Ren, Yusheng; Jiang, Qijun; Fan, Min

    2015-01-01

    Abstract Aims: High-density lipoprotein (HDL) levels inversely correlate with cardiovascular events due to the protective effects on vascular wall and stem cells, which are susceptible to oxidative modifications and then lead to potential pro-atherosclerotic effects. We proposed that oxidized HDL (ox-HDL) might lead to endothelial progenitor cells (EPCs) dysfunction and investigated underlying mechanisms. Results: ox-HDL was shown to increase apoptosis and intracellular reactive oxygen species levels, but to reduce migration, angiogenesis, and cholesterol efflux of EPCs in a dose-dependent manner. p38 mitogen-activated protein kinase (MAPK) and NF-κB were activated after ox-HDL stimulation, which also upregulated thrombospondin-1 (TSP-1) expression without affecting vascular endothelial growth factor. Effects caused by ox-HDL could be significantly attenuated by pretreatment with short hairpin RNA-mediated CD36 knockdown or probucol. Data of in vivo experiments and the inverse correlation of ox-HDL and circulating EPC numbers among patients with coronary artery diseases (CAD) or CAD and type 2 diabetes also supported it. Meanwhile, HDL separated from such patients could significantly increase cultured EPC's caspase 3 activity, further supporting our proposal. Innovation: This is the most complete study to date of how ox-HDL would impair EPCs function, which was involved with activation of CD36-p38 MAPK-TSP-1 pathways and proved by not only the inverse relationship between ox-HDL and circulating EPCs in clinic but also pro-apoptotic effects of HDL separated from patients' serum. Conclusion: Activation of CD36-p38 MAPK-TSP-1 pathways contributes to the pathological effects of ox-HDL on EPCs' dysfunction, which might be one of the potential etiological factors responsible for the disturbed neovascularization in chronic ischemic disease. Antioxid. Redox Signal. 22, 308–324. PMID:25313537

  10. Fisetin inhibits human melanoma cell invasion through promotion of mesenchymal to epithelial transition and by targeting MAPK and NFκB signaling pathways.

    PubMed

    Pal, Harish Chandra; Sharma, Samriti; Strickland, Leah Ray; Katiyar, Santosh K; Ballestas, Mary E; Athar, Mohammad; Elmets, Craig A; Afaq, Farrukh

    2014-01-01

    Malignant melanoma is responsible for approximately 75% of skin cancer-related deaths. BRAF plays an important role in regulating the mitogen-activated protein kinase (MAPK) signaling cascade in melanoma with activating mutations in the serine/threonine kinase BRAF occurring in 60-70% of malignant melanomas. The BRAF-MEK-ERK (MAPK) pathway is a key regulator of melanoma cell invasion. In addition, activation of NFκB via the MAPK pathway is regulated through MEK-induced activation of IKK. These pathways are potential targets for prevention and treatment of melanoma. In this study, we investigated the effect of fisetin, a phytochemical present in fruits and vegetables, on melanoma cell invasion and epithelial-mesenchymal transition, and delineated the underlying molecular mechanism. Treatment of multiple human malignant melanoma cell lines with fisetin (5-20 µM) resulted in inhibition of cell invasion. BRAF mutated melanoma cells were more sensitive to fisetin treatment, and this was associated with a decrease in the phosphorylation of MEK1/2 and ERK1/2. In addition, fisetin inhibited the activation of IKK leading to a reduction in the activation of the NFκB signaling pathway. Treatment of cells with an inhibitor of MEK1/2 (PD98059) or of NFκB (caffeic acid phenethyl ester) also reduced melanoma cell invasion. Furthermore, treatment of fisetin promoted mesenchymal to epithelial transition in melanoma cells, which was associated with a decrease in mesenchymal markers (N-cadherin, vimentin, snail and fibronectin) and an increase in epithelial markers (E-cadherin and desmoglein). Employing three dimensional skin equivalents consisting of A375 cells admixed with normal human keratinocytes embedded onto a collagen-constricted fibroblast matrix, we found that treatment of fisetin reduced the invasive potential of melanoma cells into the dermis and increased the expression of E-cadherin with a concomitant decrease in vimentin. These results indicate that fisetin

  11. Tartary buckwheat flavonoids protect hepatic cells against high glucose-induced oxidative stress and insulin resistance via MAPK signaling pathways.

    PubMed

    Hu, Yuanyuan; Hou, Zuoxu; Liu, Dongyang; Yang, Xingbin

    2016-03-01

    Oxidative stress plays a crucial role in chronic complication of diabetes. In this study, the protective effect of purified tartary buckwheat flavonoids (TBF) fraction 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-(Ser307)-IRS-1 expression, and glucose uptake were evaluated. Results suggest that treatment of HepG2 cells with TBF alone improved glucose uptake and antioxidant enzymes, and activated Nrf2, and attenuated the IRS-1 Ser307 phosphorylation, and enhanced total levels of IRS-1. Furthermore, the high glucose-induced changes in antioxidant defences, Nrf2, p-MAPKs, p-IRS1 Ser307, and IRS-1 levels, and glucose uptake were also significantly inhibited by pre-treatment with TBF. Interestingly, the selective MAPK inhibitors significantly enhanced the TBF-mediated protection by inducing changes in the redox status, glucose uptake, p-(Ser307) and total IRS-1 levels. This report firstly showed that TBF could recover the redox status of insulin-resistant HepG2 cells, suggesting that TBF significantly protected the cells against high glucose-induced oxidative stress, and these beneficial effects of TBF on redox balance and insulin resistance were mediated by targeting MAPKs.

  12. Oxymatrine lightened the inflammatory response of LPS-induced mastitis in mice through affecting NF-κB and MAPKs signaling pathways.

    PubMed

    Yang, Zhengtao; Yin, Ronglan; Cong, Yunfeng; Yang, Zhanqing; Zhou, Ershun; Wei, Zhengkai; Liu, Zhicheng; Cao, Yongguo; Zhang, Naisheng

    2014-12-01

    Mastitis, an inflammatory reaction of the mammary gland, is recognized as one of the most costly diseases in dairy cattle. Oxymatrine, one of the alkaloids extracted from Chinese herb Sophora flavescens Ait, has been reported to have many biological activities, such as anti-inflammatory, anti-virus, and anti-hepatic fibrosis properties. The aim of this study was to investigate the protective effect and the anti-inflammatory mechanism of oxymatrine on lipopolysaccharide (LPS)-induced mastitis in mice. The mouse mastitis was induced by 10 μg of LPS for 24 h. Oxymatrine was intraperitoneally administered with the dose of 30, 60, and 120 mg/kg 1 h before and 12 h after LPS induction. The results showed that oxymatrine significantly attenuated the damage of the mammary gland induced by LPS. Oxymatrine inhibited the phosphorylation of NF-κB p65 and IκB in NF-κB signal pathway and reduced the phosphorylation of p38, ERK, and JNK in mitogen-activated protein kinase (MAPKs) signal pathway. The results showed that oxymatrine had a protective effect on LPS-induced mastitis, and the anti-inflammatory mechanism of oxymatrine was related to the inhibition of NF-κB and MAPKs signal pathways.

  13. TNFα Signaling Regulates Cystic Epithelial Cell Proliferation through Akt/mTOR and ERK/MAPK/Cdk2 Mediated Id2 Signaling

    PubMed Central

    Zhou, Julie X.; Fan, Lucy X.; Li, Xiaoyan; Calvet, James P.; Li, Xiaogang

    2015-01-01

    Tumor necrosis factor alpha (TNFα) is present in cyst fluid and promotes cyst growth in autosomal dominant polycystic kidney disease (ADPKD). However, the cross-talk between TNFα and PKD associated signaling pathways remains elusive. In this study, we found that stimulation of renal epithelial cells with TNFα or RANKL (receptor activator of NF-κB ligand), a member of the TNFα cytokine family, activated either the PI3K pathway, leading to AKT and mTOR mediated the increase of Id2 protein, or MAPK and Cdk2 to induce Id2 nuclear translocation. The effects of TNFα/RANKL on increasing Id2 protein and its nuclear translocation caused significantly decreased mRNA and protein levels of the Cdk inhibitor p21, allowing increased cell proliferation. TNFα levels increase in cystic kidneys in response to macrophage infiltration and thus might contribute to cyst growth and enlargement during the progression of disease. As such, this study elucidates a novel mechanism for TNFα signaling in regulating cystic renal epithelial cell proliferation in ADPKD. PMID:26110849

  14. Flavokawain B, the hepatotoxic constituent from kava root, induces GSH-sensitive oxidative stress through modulation of IKK/NF-kappaB and MAPK signaling pathways.

    PubMed

    Zhou, Ping; Gross, Shimon; Liu, Ji-Hua; Yu, Bo-Yang; Feng, Ling-Ling; Nolta, Jan; Sharma, Vijay; Piwnica-Worms, David; Qiu, Samuel X

    2010-12-01

    Kava (Piper methysticum Foster, Piperaceae) organic solvent-extract has been used to treat mild to moderate anxiety, insomnia, and muscle fatigue in Western countries, leading to its emergence as one of the 10 best-selling herbal preparations. However, several reports of severe hepatotoxicity in kava consumers led the U.S. Food and Drug Administration and authorities in Europe to restrict sales of kava-containing products. Herein we demonstrate that flavokawain B (FKB), a chalcone from kava root, is a potent hepatocellular toxin, inducing cell death in HepG2 (LD(50)=15.3 ± 0.2 μM) and L-02 (LD(50)=32 μM) cells. Hepatocellular toxicity of FKB is mediated by induction of oxidative stress, depletion of reduced glutathione (GSH), inhibition of IKK activity leading to NF-κB transcriptional blockade, and constitutive TNF-α-independent activation of mitogen-activated protein kinase (MAPK) signaling pathways, namely, ERK, p38, and JNK. We further demonstrate by noninvasive bioluminescence imaging that oral consumption of FKB leads to inhibition of hepatic NF-κB transcriptional activity in vivo and severe liver damage. Surprisingly, replenishment with exogenous GSH normalizes both TNF-α-dependent NF-κB as well as MAPK signaling and rescues hepatocytes from FKB-induced death. Our data identify FKB as a potent GSH-sensitive hepatotoxin, levels of which should be specifically monitored and controlled in kava-containing herb products.

  15. Bergenin Plays an Anti-Inflammatory Role via the Modulation of MAPK and NF-κB Signaling Pathways in a Mouse Model of LPS-Induced Mastitis.

    PubMed

    Gao, Xue-jiao; Guo, Meng-yao; Zhang, Ze-cai; Wang, Tian-cheng; Cao, Yong-guo; Zhang, Nai-sheng

    2015-01-01

    Mastitis is a major disease in humans and other animals and is characterized by mammary gland inflammation. It is a major disease of the dairy industry. Bergenin is an active constituent of the plants of genus Bergenia. Research indicates that bergenin has multiple biological activities, including anti-inflammatory and immunomodulatory properties. The objective of this study was to evaluate the protective effects and mechanism of bergenin on the mammary glands during lipopolysaccharide (LPS)-induced mastitis. In this study, mice were treated with LPS to induce mammary gland mastitis as a model for the disease. Bergenin treatment was initiated after LPS stimulation for 24 h. The results indicated that bergenin attenuated inflammatory cell infiltration and decreased the concentration of NO, TNF-α, IL-1β, and IL-6, which were increased in LPS-induced mouse mastitis. Furthermore, bergenin downregulated the phosphorylation of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinases (MAPK) signaling pathway proteins in mammary glands with mastitis. In conclusion, bergenin reduced the expression of NO, TNF-α, IL-1β, and IL-6 proinflammatory cytokines by inhibiting the activation of the NF-κB and MAPKs signaling pathways, and it may represent a novel treatment strategy for mastitis.

  16. Sodium phenylacetate inhibits the Ras/MAPK signaling pathway to induce reduction of the c-Raf-1 protein in human and canine breast cancer cells.

    PubMed

    Watanabe, Manabu; Miyajima, Nozomi; Igarashi, Maki; Endo, Yoshifumi; Watanabe, Natsuko; Sugano, Sumio

    2009-11-01

    An aromatic fatty acid, phenylacetate (PA), has been shown to have cytostatic, antitumor and cell differentiation-inducing effects on various kinds of tumors. Previously, we have demonstrated cell growth inhibition, malignant phenotype reduction and cell differentiation effects of sodium phenylacetate (NaPA) treatment in a canine mammary tumor cell line. To clarify the molecular mechanism of these effects, we examined the expression of Ras/MAPK signaling pathway-related molecules in human and canine breast cancer cell lines, and found that the level of c-Raf-1 protein was reduced by 5, 10 and 20 mM of NaPA treatments, though Ras activation was maintained. Dephosphorylation of c-Raf-1 at Serine (Ser) 259, Ser 338, and Ser 621 were also seen in NaPA-treated cells. Downstream factors in the pathway, such as mitogen-activated protein kinase/ERK kinase (MEK)1/2 and ERK1/2, showed decreased activity, and accordingly, expressions of cyclinD1, c-myc, and inactivation of p90 ribosomal S6 kinase (RSK), which are MAPK targets, were reduced. We also observed the reduction of cell-cycle-promoted molecules, such as cdc1/cdk2, cdk4, PCNA cyclin A, and cyclin B, and the increased expression of p27kip1. Furthermore, expression of an epithelial marker, E-cadherin, was increased by NaPA treatment. These results suggest that one of the molecular targets of NaPA treatment was the reduction of c-Raf-1 protein, and that its reduction results in the decrease of malignant characteristics of tumor cells through blockage of the Ras/MAPK signaling pathway.

  17. KSR is a scaffold required for activation of the ERK/MAPK module

    PubMed Central

    Roy, François; Laberge, Gino; Douziech, Mélanie; Ferland-McCollough, David; Therrien, Marc

    2002-01-01

    Mechanisms that regulate signal propagation through the ERK/MAPK pathway are still poorly understood. Several proteins are suspected to play critical roles in this process. One of these is Kinase Suppressor of Ras (KSR), a component previously identified in RAS-dependent genetic screens in Drosophila and Caenorhabditis elegans. Here, we show that KSR functions upstream of MEK within the ERK/MAPK module. In agreement with this, we found that KSR facilitates the phosphorylation of MEK by RAF. We further show that KSR associates independently with RAF and MEK, and that these interactions lead to the formation of a RAF/MEK complex, thereby positioning RAF in close proximity to its substrate MEK. These findings suggest that KSR functions as a scaffold that assembles the RAF/MEK functional pair. PMID:11850406

  18. Dioscin inhibits colon tumor growth and tumor angiogenesis through regulating VEGFR2 and AKT/MAPK signaling pathways

    SciTech Connect

    Tong, Qingyi; Qing, Yong; Wu, Yang; Hu, Xiaojuan; Jiang, Lei; Wu, Xiaohua

    2014-12-01

    Dioscin has shown cytotoxicity against cancer cells, but its in vivo effects and the mechanisms have not elucidated yet. The purpose of the current study was to assess the antitumor effects and the molecular mechanisms of dioscin. We showed that dioscin could inhibit tumor growth in vivo and has no toxicity at the test condition. The growth suppression was accompanied by obvious blood vessel decrease within solid tumors. We also found dioscin treatment inhibited the proliferation of cancer and endothelial cell lines, and most sensitive to primary cultured human umbilical vein endothelial cells (HUVECs). What's more, analysis of HUVECs migration, invasion, and tube formation exhibited that dioscin has significantly inhibitive effects to these actions. Further analysis of blood vessel formation in the matrigel plugs indicated that dioscin could inhibit VEGF-induced blood vessel formation in vivo. We also identified that dioscin could suppress the downstream protein kinases of VEGFR2, including Src, FAK, AKT and Erk1/2, accompanied by the increase of phosphorylated P38MAPK. The results potently suggest that dioscin may be a potential anticancer drug, which efficiently inhibits angiogenesis induced by VEGFR2 signaling pathway as well as AKT/MAPK pathways. - Highlights: • Dioscin inhibits tumor growth in vivo and does not exhibit any toxicity. • Dioscin inhibits angiogenesis within solid tumors. • Dioscin inhibits the proliferation, migration, invasion, and tube formation of HUVECs. • Dioscin inhibits VEGF–induced blood vessel formation in vivo. • Dioscin inhibits VEGFR2 signaling pathway as well as AKT/MAPK pathway.

  19. IL-1α Expression in Pancreatic Ductal Adenocarcinoma Affects the Tumor Cell Migration and Is Regulated by the p38MAPK Signaling Pathway

    PubMed Central

    Tjomsland, Vegard; Bojmar, Linda; Sandström, Per; Bratthäll, Charlotte; Messmer, Davorka; Spångeus, Anna; Larsson, Marie

    2013-01-01

    The interplay between the tumor cells and the surrounding stroma creates inflammation, which promotes tumor growth and spread. The inflammation is a hallmark for pancreatic adenocarcinoma (PDAC) and is to high extent driven by IL-1α. IL-1α is expressed and secreted by the tumor cells and exerting its effect on the stroma, i.e. cancer associated fibroblasts (CAF), which in turn produce massive amount of inflammatory and immune regulatory factors. IL-1 induces activation of transcription factors such as nuclear factor-κβ (NF-κβ), but also activator protein 1 (AP-1) via the small G-protein Ras. Dysregulation of Ras pathways are common in cancer as this oncogene is the most frequently mutated in many cancers. In contrast, the signaling events leading up to the expression of IL-1α by tumor cells are not well elucidated. Our aim was to examine the signaling cascade involved in the induction of IL-1α expression in PDAC. We found p38MAPK, activated by the K-Ras signaling pathway, to be involved in the expression of IL-1α by PDAC as blocking this pathway decreased both the gene and protein expression of IL-1α. Blockage of the P38MAPK signaling in PDAC also dampened the ability of the tumor cell to induce inflammation in CAFs. In addition, the IL-1α autocrine signaling regulated the migratory capacity of PDAC cells. Taken together, the blockage of signaling pathways leading to IL-1α expression and/or neutralization of IL-1α in the PDAC microenvironment should be taken into consideration as possible treatment or complement to existing treatment of this cancer. PMID:23951028

  20. PSMA redirects cell survival signaling from the MAPK to the PI3K-AKT pathways to promote the progression of prostate cancer.

    PubMed

    Caromile, Leslie Ann; Dortche, Kristina; Rahman, M Mamunur; Grant, Christina L; Stoddard, Christopher; Ferrer, Fernando A; Shapiro, Linda H

    2017-03-14

    Increased abundance of the prostate-specific membrane antigen (PSMA) on prostate epithelium is a hallmark of advanced metastatic prostate cancer (PCa) and correlates negatively with prognosis. However, direct evidence that PSMA functionally contributes to PCa progression remains elusive. We generated mice bearing PSMA-positive or PSMA-negative PCa by crossing PSMA-deficient mice with transgenic PCa (TRAMP) models, enabling direct assessment of PCa incidence and progression in the presence or absence of PSMA. Compared with PSMA-positive tumors, PSMA-negative tumors were smaller, lower-grade, and more apoptotic with fewer blood vessels, consistent with the recognized proangiogenic function of PSMA. Relative to PSMA-positive tumors, tumors lacking PSMA had less than half the abundance of type 1 insulin-like growth factor receptor (IGF-1R), less activity in the survival pathway mediated by PI3K-AKT signaling, and more activity in the proliferative pathway mediated by MAPK-ERK1/2 signaling. Biochemically, PSMA interacted with the scaffolding protein RACK1, disrupting signaling between the β1 integrin and IGF-1R complex to the MAPK pathway, enabling activation of the AKT pathway instead. Manipulation of PSMA abundance in PCa cell lines recapitulated this signaling pathway switch. Analysis of published databases indicated that IGF-1R abundance, cell proliferation, and expression of transcripts for antiapoptotic markers positively correlated with PSMA abundance in patients, suggesting that this switch may be relevant to human PCa. Our findings suggest that increase in PSMA in prostate tumors contributes to progression by altering normal signal transduction pathways to drive PCa progression and that enhanced signaling through the IGF-1R/β1 integrin axis may occur in other tumors.

  1. Astragaloside IV suppresses transforming growth factor-β1 induced fibrosis of cultured mouse renal fibroblasts via inhibition of the MAPK and NF-κB signaling pathways

    SciTech Connect

    Che, Xiajing; Wang, Qin; Xie, Yuanyuan; Xu, Weijia; Shao, Xinghua; Mou, Shan Ni, Zhaohui

    2015-09-04

    Renal fibrosis, a progressive process characterized by the accumulation of extracellular matrix (ECM) leading to organ dysfunction, is a characteristic of chronic kidney diseases. Among fibrogenic factors known to regulate the renal fibrotic process, transforming growth factor-β (TGF-β) plays a central role. In the present study, we examined the effect of Astragaloside IV (AS-IV), a component of the traditional Chinese medicinal plant Astragalus membranaceus, on the processes associated with renal fibrosis in cultured mouse renal fibroblasts treated with TGF-β1. RT-PCR, western blotting, immunofluorescence staining and collagen assays showed that AS-IV suppressed TGF-β1 induced fibroblast proliferation, transdifferentiation, and ECM production in a dose-dependent manner. Examination of the underlying mechanisms showed that the effect of AS-IV on the inhibition of fibroblast differentiation and ECM formation were mediated by its modulation of the activity of the MAPK and NF-κB signaling pathways. Taken together, our results indicate that AS-IV alleviates renal interstitial fibrosis via a mechanism involving the MAPK and NF-κB signaling pathways and demonstrate the therapeutic potential of AS-IV for the treatment of chronic kidney diseases. - Highlights: • AS-IV suppressed TGF-β1 induced renal fibroblast proliferation. • AS-IV suppressed TGF-β1 induced renal fibroblast transdifferentiation. • AS-IV suppressed TGF-β1 induced ECM production. • AS-IV alleviates renal fibrosis via the MAPK and NF-κB signaling pathways.

  2. NFATC1 promotes cell growth and tumorigenesis in ovarian cancer up-regulating c-Myc through ERK1/2/p38 MAPK signal pathway.

    PubMed

    Xu, Wenwen; Gu, Junjie; Ren, Qingling; Shi, Yanqiu; Xia, Qinhua; Wang, Jing; Wang, Suli; Wang, Yingchun; Wang, Jinhua

    2016-04-01

    It has been reported that nuclear factor of activated T cells (NFATC1) was up-regulated in cancers mediating malignant behaviors. However, the role of NFATC1 in ovarian cancer has not been elucidated. In the present study, we undertook to explore the clinicopathological significance of NFATC1 expression and the mechanism by which NFATC1 works in ovarian cancer. Expression status of NFATC1 was examined using immunohistochemistry. Both knockdown and re-expression of NFATC1 on ovarian cancer cells were employed to observe the effect overgrowth. It was found that NFATC1 was significantly overexpressed in ovarian cancer tissues in comparison with paired normal control tissues and that overexpression of NFATC1 was significantly associated with metastasis and poor prognosis on clinical tissue level. In in vitro ovarian cancer cell lines, we found that NFATC1 can promote proliferation up-regulating c-myc through activation of ERK1/2/p38/MAPK signal pathway. Together, the results we obtained demonstrated that NFATC1 played oncogenic role in ovarian cancer. Mechanistically, NFATC1 promoted growth of ovarian cancer cells up-regulating c-myc through activation of ERK1/2/p38/MAPK signal pathway, suggesting that NFATC1 might be used as a therapeutic target for ovarian cancer.

  3. Effects of budesonide on P38 MAPK activation, apoptosis and IL-8 secretion, induced by TNF-alpha and Haemophilus influenzae in human bronchial epithelial cells.

    PubMed

    Gallelli, L; Pelaia, G; Fratto, D; Muto, V; Falcone, D; Vatrella, A; Curto, L S; Renda, T; Busceti, M T; Liberto, M C; Savino, R; Cazzola, M; Marsico, S A; Maselli, R

    2010-01-01

    Non-typeable Haemophilus influenzae (NTHi) is one of the most frequently involved pathogens in bacterial exacerbations of chronic obstructive pulmonary disease (COPD). In the airways, the main tissue target of NTHi is bronchial epithelium, where this pathogen can further amplify the inflammatory and structural changes induced by proinflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha). Therefore, the aim of this study is to investigate, in primary cultures of human bronchial epithelial cells, the effects of NTHi on signal transduction pathways, apoptotic events and chemokine production activated by TNF-alpha. Moreover, we also evaluated the effects exerted on such cellular and molecular phenomena by a corticosteroid drug. p38 mitogen-activated protein kinase (MAPK) phosphorylation was analyzed by Western blotting, using an anti-phospho-p38 MAPK monoclonal antibody. Apoptosis was assayed by active caspase-3 expression. Interleukin-8 (IL-8/CXCL8) was detected in cell-free culture supernatants by ELISA. TNF-alpha induced a significant increase in p38 MAPK phosphorylation. NTHi was able to potentiate the stimulatory actions of TNF-alpha on caspase-3 expression and, to a lesser extent, on IL-8 secretion. These effects were significantly (P less than 0.01) inhibited by a pharmacological pre-treatment with budesonide. These results suggest that TNF-alpha is able to stimulate, via activation of p38 MAPK signalling pathway, IL-8 release and airway epithelial cell apoptosis; the latter effect can be markedly potentiated by NTHi. Furthermore, budesonide can be very effective in preventing, through inhibition of p38 MAPK phosphorylation, both structural and proinflammatory changes elicited in bronchial epithelium by TNF-alpha and NTHi.

  4. 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

  5. CFTR-regulated MAPK/NF-κB signaling in pulmonary inflammation in thermal inhalation injury

    PubMed Central

    Dong, Zhi Wei; Chen, Jing; Ruan, Ye Chun; Zhou, Tao; Chen, Yu; Chen, YaJie; Tsang, Lai Ling; Chan, Hsiao Chang; Peng, Yi Zhi

    2015-01-01

    The mechanism underlying pulmonary inflammation in thermal inhalation injury remains elusive. Cystic fibrosis, also hallmarked with pulmonary inflammation, is caused by mutations in CFTR, the expression of which is temperature-sensitive. We investigated whether CFTR is involved in heat-induced pulmonary inflammation. We applied heat-treatment in 16HBE14o- cells with CFTR knockdown or overexpression and heat-inhalation in rats in vivo. Heat-treatment caused significant reduction in CFTR and, reciprocally, increase in COX-2 at early stages both in vitro and in vivo. Activation of ERK/JNK, NF-κB and COX-2/PGE2 were detected in heat-treated cells, which were mimicked by knockdown, and reversed by overexpression of CFTR or VX-809, a reported CFTR mutation corrector. JNK/ERK inhibition reversed heat-/CFTR-knockdown-induced NF-κB activation, whereas NF-κB inhibitor showed no effect on JNK/ERK. IL-8 was augmented by heat-treatment or CFTR-knockdown, which was abolished by inhibition of NF-κB, JNK/ERK or COX-2. Moreover, in vitro or in vivo treatment with curcumin, a natural phenolic compound, significantly enhanced CFTR expression and reversed the heat-induced increases in COX-2/PGE2/IL-8, neutrophil infiltration and tissue damage in the airway. These results have revealed a CFTR-regulated MAPK/NF-κB pathway leading to COX-2/PGE2/IL-8 activation in thermal inhalation injury, and demonstrated therapeutic potential of curcumin for alleviating heat-induced pulmonary inflammation. PMID:26515683

  6. Positive regulation of the Egr-1/osteopontin positive feedback loop in rat vascular smooth muscle cells by TGF-{beta}, ERK, JNK, and p38 MAPK signaling

    SciTech Connect

    Yu, Hong-Wei; Liu, Qi-Feng; Liu, Gui-Nan

    2010-05-28

    Previous studies identified a positive feedback loop in rat vascular smooth muscle cells (VSMCs) in which early growth response factor-1 (Egr-1) binds to the osteopontin (OPN) promoter and upregulates OPN expression, and OPN upregulates Egr-1 expression via the extracellular signal-regulated protein kinase (ERK) signaling pathway. The current study examined whether transforming growth factor-{beta} (TGF-{beta}) activity contributes to Egr-1 binding to the OPN promoter, and whether other signaling pathways act downstream of OPN to regulate Egr-1 expression. ChIP assays using an anti-Egr-1 antibody showed that amplification of the OPN promoter sequence decreased in TGF-{beta} DNA enzyme-transfected VSMCs relative to control VSMCs. Treatment of VSMCs with PD98059 (ERK inhibitor), SP600125 (JNK inhibitor), or SB203580 (p38 MAPK inhibitor) significantly inhibited OPN-induced Egr-1 expression, and PD98059 treatment was associated with the most significant decrease in Egr-1 expression. OPN-stimulated VSMC cell migration was inhibited by SP600125 or SB203580, but not by PD98059. Furthermore, MTT assays showed that OPN-mediated cell proliferation was inhibited by PD98059, but not by SP600125 or SB203580. Taken together, the results of the current study show that Egr-1 binding to the OPN promoter is positively regulated by TGF-{beta}, and that the p38 MAPK, JNK, and ERK pathways are involved in OPN-mediated Egr-1 upregulation.

  7. Genetic alterations related to BRAF-FGFR genes and dysregulated MAPK/ERK/mTOR signaling in adult pilocytic astrocytoma.

    PubMed

    Pathak, Pankaj; Kumar, Anupam; Jha, Prerana; Purkait, Suvendu; Faruq, Mohammed; Suri, Ashish; Suri, Vaishali; Sharma, Mehar C; Sarkar, Chitra

    2016-09-08

    inversely correlates with increasing age whereas FGFR1-mutation associates with older age. Activation of MAPK/ERK/mTOR signaling appears to be an important oncogenic event in APAs and may be underlying event of aggressive tumor behavior. The findings provided a rationale for potential therapeutic advantage of targeting MAPK/ERK/mTOR pathway in APAs.

  8. Carbocisteine attenuates TNF-α-induced inflammation in human alveolar epithelial cells in vitro through suppressing NF-κB and ERK1/2 MAPK signaling pathways

    PubMed Central

    Wang, Wei; Guan, Wei-jie; Huang, Rong-quan; Xie, Yan-qing; Zheng, Jin-ping; Zhu, Shao-xuan; Chen, Mao; Zhong, Nan-shan

    2016-01-01

    Aim: We previously proven that carbocisteine, a conventional mucolytic drug, remarkably reduced the rate of acute exacerbations and improved the quality of life in the patients with chronic obstructive pulmonary disease. In this study we investigated the mechanisms underlying the anti-inflammatory effects of carbocisteine in human alveolar epithelial cells in vitro. Methods: Human lung adenocarcinoma cell line A549 was treated with TNF-α (10 ng/mL). Carbocisteine was administered either 24 h prior to or after TNF-α exposure. The cytokine release and expression were measured using ELISA and qRT-PCR. Activation of NF-κB was analyzed with Western blotting, immunofluorescence assay and luciferase reporter gene assay. The expression of ERK1/2 MAPK signaling proteins was assessed with Western blotting. Results: Carbocisteine (10, 100, 1000 μmol/L), administered either before or after TNF-α exposure, dose-dependently suppressed TNF-α-induced inflammation in A549 cells, as evidenced by diminished release of IL-6 and IL-8, and diminished mRNA expression of IL-6, IL-8, TNF-α, MCP-1 and MIP-1β. Furthermore, pretreatment with carbocisteine significantly decreased TNF-α-induced phosphorylation of NF-κB p65 and ERK1/2 MAPK, and inhibited the nuclear translocation of p65 subunit in A549 cells. In an NF-κB luciferase reporter system, pretreatment with carbocisteine dose-dependently inhibited TNF-α-induced transcriptional activity of NF-κB. Conclusion: Carbocisteine effectively suppresses TNF-α-induced inflammation in A549 cells via suppressing NF-κB and ERK1/2 MAPK signaling pathways. PMID:26997568

  9. Delphinidin suppresses proliferation and migration of human ovarian clear cell carcinoma cells through blocking AKT and ERK1/2 MAPK signaling pathways.

    PubMed

    Lim, Whasun; Jeong, Wooyoung; Song, Gwonhwa

    2016-02-15

    Delphinidin possesses the highest chemopreventive activity among the six components of anthocyanidin that are pigments from fruits and vegetables giving them blue, purple or red colors. Although delphinidin has anti-carcinogenic and apoptotic effects in various cancers, little is known about its functional roles in ovarian clear cell carcinoma (CCC) which shows poor prognosis with resistance to chemotherapy as compared with other subtypes of epithelial ovarian cancers (EOC). Results of present study revealed that cell survival rates of ES2 cells from ovarian CCC treated with delphinidin decreased in a dose-dependent manner. Also, delphinidin inhibited migration and induced apoptosis of ES2 cells. To investigate the molecular mechanisms responsible for biological effects of delphinidin, we analyzed the phosphorylation status of carcinogenic protein kinases related to development of CCC in a dose- and time-dependent manner. Phosphorylation of downstream targets of PI3K (AKT and p70S6K) and MAPKs (ERK1/2 and JNK) signaling was suppressed by treatment of ES2 cells with delphinidin. In addition, pharmacological inhibitors of PI3K/AKT and ERK1/2 MAPK pathway improved the anti-proliferative action of delphinidin on ES2 cells. Moreover, we compared the cancer preventive effects of delphinidin with traditional cisplatin- and paclitaxel-based chemotherapy on cell viability of ES2 cells. Results showed that delphinidin is as effective in its therapeutic activity against ES2 cells as cisplatin and placlitaxel. Collectively, these results indicated that delphinidin plays a critical role as a new chemotherapeutic agent to prevent development and progression of ES2 cells in CCC via inactivation of PI3K/AKT and ERK1/2 MAPK signal transduction cascades.

  10. GENE REGULATION BY MAPK SUBSTRATE COMPETITION

    PubMed Central

    Kim, Yoosik; Andreu, María José; Lim, Bomyi; Chung, Kwanghun; Terayama, Mark; Jiménez, Gerardo; Berg, Celeste A.; Lu, Hang; Shvartsman, Stanislav Y.

    2011-01-01

    SUMMARY Developing tissues are patterned by coordinated activities of signaling systems, which can be integrated by a regulatory region of a gene that binds multiple transcription factors or by a transcription factor that is modified by multiple enzymes. Based on a combination of genetic and imaging experiments in the early Drosophila embryo, we describe a signal integration mechanism that cannot be reduced to a single gene regulatory element or a single transcription factor. This mechanism relies on an enzymatic network formed by Mitogen Activated Protein Kinase (MAPK) and its substrates. Specifically, anteriorly localized MAPK substrates, such as Bicoid, antagonize MAPK-dependent downregulation of Capicua, a repressor which is involved in gene regulation along the dorsoventral axis of the embryo. MAPK substrate competition provides a basis for ternary interaction of the anterior, dorsoventral, and terminal patterning systems. A mathematical model of this interaction can explain gene expression patterns with both anteroposterior and dorsoventral polarities. PMID:21664584

  11. The Combination of Three Components Derived from Sheng MaiSan Protects Myocardial Ischemic Diseases and Inhibits Oxidative Stress via Modulating MAPKs and JAK2-STAT3 Signaling Pathways Based on Bioinformatics Approach

    PubMed Central

    Li, Fang; Zhang, Yu; Zeng, Donglin; Xia, Yu; Fan, Xiaoxue; Tan, Yisha; Kou, Junping; Yu, Boyang

    2017-01-01

    GRS is a drug combination of three components including ginsenoside Rb1, ruscogenin and schisandrin. It derived from the well-known TCM formula Sheng MaiSan, a widely used traditional Chinese medicine for the treatment of cardiovascular diseases in clinic. The present study illuminates its underlying mechanisms against myocardial ischemic diseases based on the combined methods of bioinformatic prediction and experimental verification. A protein database was established through constructing the drug-protein network. And the target-pathway interaction network clustered the potential signaling pathways and targets of GRS in treatment of myocardial ischemic diseases. Several target proteins, such as NFKB1, STAT3 and MAPK14, were identified as the candidate key proteins, and MAPKs and JAK-STAT signaling pathway were suggested as the most related pathways, which were in accordance with the gene ontology analysis. Then, the predictive results were further validated and we found that GRS treatment alleviated hypoxia/reoxygenation (H/R)-induced cardiomyocytes injury via suppression of MDA levels and ROS generation, and potential mechanisms might related to the suppression of activation of MAPKs and JAK2-STAT3 signaling pathways. Conclusively, our results offer the evidence that GRS attenuates myocardial ischemia injury via regulating oxidative stress and MAPKs and JAK2-STAT3 signaling pathways, which supplied some new insights for its prevention and treatment of myocardial ischemia diseases. PMID:28197101

  12. Palmitoleic acid prevents palmitic acid-induced macrophage activation and consequent p38 MAPK-mediated skeletal muscle insulin resistance.

    PubMed

    Talbot, Nicola A; Wheeler-Jones, Caroline P; Cleasby, Mark E

    2014-08-05

    Obesity and saturated fatty acid (SFA) treatment are both associated with skeletal muscle insulin resistance (IR) and increased macrophage infiltration. However, the relative effects of SFA and unsaturated fatty acid (UFA)-activated macrophages on muscle are unknown. Here, macrophages were treated with palmitic acid, palmitoleic acid or both and the effects of the conditioned medium (CM) on C2C12 myotubes investigated. CM from palmitic acid-treated J774s (palm-mac-CM) impaired insulin signalling and insulin-stimulated glycogen synthesis, reduced Inhibitor κBα and increased phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase in myotubes. p38 MAPK inhibition or siRNA partially ameliorated these defects, as did addition of tumour necrosis factor-α blocking antibody to the CM. Macrophages incubated with both FAs generated CM that did not induce IR, while palmitoleic acid-mac-CM alone was insulin sensitising. Thus UFAs may improve muscle insulin sensitivity and counteract SFA-mediated IR through an effect on macrophage activation.

  13. A novel cysteine-rich neurotrophic factor in Aplysia facilitates growth, MAPK activation, and long-term synaptic facilitation.

    PubMed

    Pu, Lu; Kopec, Ashley M; Boyle, Heather D; Carew, Thomas J

    2014-04-01

    Neurotrophins are critically involved in developmental processes such as neuronal cell survival, growth, and differentiation, as well as in adult synaptic plasticity contributing to learning and memory. Our previous studies examining neurotrophins and memory formation in Aplysia showed that a TrkB ligand is required for MAPK activation, long-term synaptic facilitation (LTF), and long-term memory (LTM) for sensitization. These studies indicate that neurotrophin-like molecules in Aplysia can act as key elements in a functionally conserved TrkB signaling pathway. Here we report that we have cloned and characterized a novel neurotrophic factor, Aplysia cysteine-rich neurotrophic factor (apCRNF), which shares classical structural and functional characteristics with mammalian neurotrophins. We show that apCRNF (1) is highly enriched in the CNS, (2) enhances neurite elongation and branching, (3) interacts with mammalian TrkB and p75(NTR), (4) is released from Aplysia CNS in an activity-dependent fashion, (5) facilitates MAPK activation in a tyrosine kinase dependent manner in response to sensitizing stimuli, and (6) facilitates the induction of LTF. These results show that apCRNF is a native neurotrophic factor in Aplysia that can engage the molecular and synaptic mechanisms underlying memory formation.

  14. Induction of p21(Waf1/Cip1) by garcinol via downregulation of p38-MAPK signaling in p53-independent H1299 lung cancer.

    PubMed

    Yu, Sheng-Yung; Liao, Chiung-Ho; Chien, Ming-Hsien; Tsai, Tsung-Yu; Lin, Jen-Kun; Weng, Meng-Shih

    2014-03-05

    Garcinol, a polyisoprenylated benzophenone, from Garcinia indica fruit rind has possessed anti-inflammatory, antioxidant, antiproliferation, and anticancer activities. However, the anticancer mechanisms of garcinol in lung cancer were still unclear. Therefore, we examine the effects of garcinol on antiproliferation in human lung cancer cells. Treatments with garcinol for 24 h exhibited morphological changes and inhibited the proliferation of H460 (p53-wild type) and H1299 (p53-null) cells in dose- and time-dependent manners. Furthermore, a significant G1 cell cycle arrest was observed in a dose-dependent treatment after H1299 cells were exposed in garcinol, whereas garcinol induced apoptosis rather than cell cycle arrest in H460 cells. Moreover, cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4), cyclin D1, and cyclin D3 were decreased, although cyclin E and cyclin-dependent kinase 6 (CDK6) were increased in garcinol-treated H1299 cells. Meanwhile, the protein levels of CDK inhibitors p21(Waf1/Cip1) and p27(KIP1) also exhibited upregulation after garcinol treatments. The enhanced protein-associated level between p21(Waf1/Cip1) and CDK4/2 rather than p27(KIP1) and CDK4/2 was demonstrated in garcinol-treated cells. Additionally, knock-down p21(Waf1/Cip1) by specific siRNA competently prevented garcinol-induced G1 arrest. Besides, garcinol also inhibited ERK and p38-MAPK activations in time-dependent mode. The pretreatment with p38-MAPK inhibitor but not ERK inhibitor raised garcinol-induced G1 population cells. Co-treatment with p38-MAPK inhibitor and garcinol synergistically elevated cyclin E, p21(Waf1/Cip1), and p27(Kip1) expressions. Meanwhile, overexpression dominant negative p38-MAPK also enhanced garcinol-induced p21(Waf1/Cip1) expression in H1299 cells. Accordingly, our data suggested that garcinol induced G1 cell cycle arrest and apoptosis in lung cancer cells under different p53 statuses. The p53-independent G1 cell cycle arrest induced by

  15. Upregulation of cell proliferation via Shc and ERK1/2 MAPK signaling in SaOS-2 osteoblasts grown on magnesium alloy surface coating with tricalcium phosphate.

    PubMed

    Jiang, Tianlong; Guo, Lei; Ni, Shenghui; Zhao, Yuyan

    2015-04-01

    Magnesium (Mg) alloys have been demonstrated to be viable orthopedic implants because of mechanical and biocompatible properties similar to natural bone. In order to improve its osteogenic properties, a porous β-tricalcium phosphate (β-TCP) was coated on the Mg-3AI-1Zn alloy by alkali-heat treatment technique. The human bone-derived cells (SaOS-2) were cultured on (β-TCP)-Mg-3AI-1Zn in vitro, and the osteoblast response, the morphology and the elements on this alloy surface were investigated. Also, the regulation of key intracellular signalling proteins was investigated in the SaOS-2 cells cultured on alloy surface. The results from scanning electron microscope and immunofluorescence staining demonstrated that (β-TCP)-Mg-3AI-1Zn induced significant osteogenesis. SaOS-2 cell proliferation was improved by β-TCP coating. Moreover, the (β-TCP)-Mg-3AI-1Zn surface induced activation of key intracellular signalling proteins in SaOS-2 cells. We observed an enhanced activation of Src homology and collagen (Shc), a common point of integration between bone morphogenetic protein 2, and the Ras/mitogen-activated protein kinase (MAPK) pathway. ERK1/2 MAP kinase activation was also upregulated, suggesting a role in mediating osteoblastic cell interactions with biomaterials. The signalling pathway involving c-fos (member of the activated protein-1) was also shown to be upregulated in osteoblasts cultured on the (β-TCP)-Mg-3AI-1Zn. These results suggest that β-TCP coating may contribute to successful osteoblast function on Mg alloy surface. (β-TCP)-Mg-3AI-1Zn may upregulate cell proliferation via Shc and ERK1/2 MAPK signaling in SaOS-2 osteoblasts grown on Mg alloy surface.

  16. cAMP induction by ouabain promotes endothelin-1 secretion via MAPK/ERK signaling in beating rabbit atria.

    PubMed

    Peng, Li-Qun; Li, Ping; Zhang, Qiu-Li; Hong, Lan; Liu, Li-Ping; Cui, Xun; Cui, Bai-Ri

    2016-01-01

    Adenosine 3',5'-cyclic monophosphate (cAMP) participates in the regulation of numerous cellular functions, including the Na(+)-K(+)-ATPase (sodium pump). Ouabain, used in the treatment of several heart diseases, is known to increase cAMP levels but its effects on the atrium are not understood. The aim of the present study was to examine the effect of ouabain on the regulation of atrial cAMP production and its roles in atrial endothelin-1 (ET-1) secretion in isolated perfused beating rabbit atria. Our results showed that ouabain (3.0 µmol/L) significantly increased atrial dynamics and cAMP levels during recovery period. The ouabain-increased atrial dynamics was blocked by KB-R7943 (3.0 µmol/L), an inhibitor for reverse mode of Na(+)-Ca(2+) exchangers (NCX), but did not by L-type Ca(2+) channel blocker nifedipine (1.0 µmol/L) or protein kinase A (PKA) selective inhibitor H-89 (3.0 µmol/L). Ouabain also enhanced atrial intracellular cAMP production in response to forskolin and theophyline (100.0 µmol/L), an inhibitor of phosphodiesterase, potentiated the ouabain-induced increase in cAMP. Ouabain and 8-Bromo-cAMP (0.5 µmol/L) markedly increased atrial ET-1 secretion, which was blocked by H-89 and by PD98059 (30 µmol/L), an inhibitor of extracellular-signal-regulated kinase (ERK) without changing ouabain-induced atrial dynamics. Our results demonstrated that ouabain increases atrial cAMP levels and promotes atrial ET-1 secretion via the mitogen-activated protein kinase (MAPK)/ERK signaling pathway. These findings may explain the development of cardiac hypertrophy in response to digitalis-like compounds.

  17. MAPKAPK-2 modulates p38-MAPK localization and small heat shock protein phosphorylation but does not mediate the injury associated with p38-MAPK activation during myocardial ischemia

    PubMed Central

    Gorog, Diana A.; Jabr, Rita I; Tanno, Masaya; Sarafraz, Negin; Clark, James E.; Fisher, Simon G.; Cao, Xou Bin; Bellahcene, Mohamed; Dighe, Kushal; Kabir, Alamgir M. N.; Quinlan, Roy A.; Kato, Kanefusa; Gaestel, Matthias; Marber, Michael S.

    2009-01-01

    MAPKAPK-2 (MK2) is a protein kinase activated downstream of p38-MAPK which phosphorylates the small heat shock proteins HSP27 and αB crystallin and modulates p38-MAPK cellular distribution. p38-MAPK activation is thought to contribute to myocardial ischemic injury; therefore, we investigated MK2 effects on ischemic injury and p38 cellular localization using MK2-deficient mice (KO). Immunoblotting of extracts from Langendorff-perfused hearts subjected to aerobic perfusion or global ischemia or reperfusion showed that the total and phosphorylated p38 levels were significantly lower in MK2−/− compared to MK2+/+ hearts at baseline, but the ratio of phosphorylated/total p38 was similar. These results were confirmed by cellular fractionation and immunoblotting for both cytosolic and nuclear compartments. Furthermore, HSP27 and αB crsytallin phosphorylation were reduced to baseline in MK2−/− hearts. On semiquantitative immunofluorescence laser confocal microscopy of hearts during aerobic perfusion, the mean total p38 fluorescence was significantly higher in the nuclear compared to extranuclear (cytoplasmic, sarcomeric, and sarcolemmal compartments) in MK2+/+ hearts. However, although the increase in phosphorylated p38 fluorescence intensity in all compartments following ischemia in MK2+/+ hearts was lost in MK2−/− hearts, it was basally elevated in nuclei of MK2−/− hearts and was similar to that seen during ischemia in MK2+/+ hearts. Despite these differences, similar infarct volumes were recorded in wild-type MK2+/+ and MK2−/− hearts, which were decreased by the p38 inhibitor SB203580 (1 μM) in both genotypes. In conclusion, p38 MAPK-induced myocardial ischemic injury is not modulated by MK2. However, the absence of MK2 perturbs the cellular distribution of p38. The preserved nuclear distribution of active p38 MAPK in MK2−/− hearts and the conserved response to SB203580 suggests that activation of p38 MAPK may contribute to injury

  18. A Standardized Chemically Modified Curcuma longa Extract Modulates IRAK-MAPK Signaling in Inflammation and Potentiates Cytotoxicity

    PubMed Central

    Rana, Minakshi; Maurya, Preeti; Reddy, Sukka S.; Singh, Vishal; Ahmad, Hafsa; Dwivedi, Anil K.; Dikshit, Madhu; Barthwal, Manoj K.

    2016-01-01

    The TLR/IL-1R pathway is a critical signaling module that is misregulated in pathologies like inflammation and cancer. Extracts from turmeric (Curcuma longa L.) enriched in curcumin and carbonyls like turmerones have been shown to exert potent anti-inflammatory effects. The present study evaluated the anti-inflammatory activity, cytotoxic effect and the underlying mechanism of a novel chemically modified, non-carbonyl compound enriched Curcuma longa L. (C. longa) extract (CMCE). CMCE (1 or 10 μg/mL; 14 h) significantly decreased LPS (50-100 ng/mL) induced TNF-α and IL-1β production in THP-1 cells, human, and mouse whole blood as measured by ELISA. LPS-induced IRAK1, MAPK activation, TLR4 expression, TLR4-MyD88 interaction, and IκBα degradation were significantly reduced in CMCE pre-treated THP-1 cells as assessed by Western blotting. CMCE (30, 100, and 300 mg/kg; 10 days p.o.) pre-treated and LPS (10 mg/kg) challenged Swiss mice exhibited attenuated plasma TNF-α, IL-1β, nitrite, aortic iNOS expression, and vascular dysfunction. In a PI permeability assay, cell lines derived from acute myeloid leukemia were most sensitive to the cytotoxic effects of CMCE. Analysis of Sub-G1 phase, Annexin V-PI positivity, loss of mitochondrial membrane potential, increased caspase-3, and PARP-1 activation confirmed CMCE induced apoptosis in HL-60 cells. IRAK inhibition also sensitized HL-60 cells to CMCE induced cytotoxicity. The present study defines the mechanism underlying the action of CMCE and suggests a therapeutic potential for its use in sepsis and leukemia. PMID:27504095

  19. A Standardized Chemically Modified Curcuma longa Extract Modulates IRAK-MAPK Signaling in Inflammation and Potentiates Cytotoxicity.

    PubMed

    Rana, Minakshi; Maurya, Preeti; Reddy, Sukka S; Singh, Vishal; Ahmad, Hafsa; Dwivedi, Anil K; Dikshit, Madhu; Barthwal, Manoj K

    2016-01-01

    The TLR/IL-1R pathway is a critical signaling module that is misregulated in pathologies like inflammation and cancer. Extracts from turmeric (Curcuma longa L.) enriched in curcumin and carbonyls like turmerones have been shown to exert potent anti-inflammatory effects. The present study evaluated the anti-inflammatory activity, cytotoxic effect and the underlying mechanism of a novel chemically modified, non-carbonyl compound enriched Curcuma longa L. (C. longa) extract (CMCE). CMCE (1 or 10 μg/mL; 14 h) significantly decreased LPS (50-100 ng/mL) induced TNF-α and IL-1β production in THP-1 cells, human, and mouse whole blood as measured by ELISA. LPS-induced IRAK1, MAPK activation, TLR4 expression, TLR4-MyD88 interaction, and IκBα degradation were significantly reduced in CMCE pre-treated THP-1 cells as assessed by Western blotting. CMCE (30, 100, and 300 mg/kg; 10 days p.o.) pre-treated and LPS (10 mg/kg) challenged Swiss mice exhibited attenuated plasma TNF-α, IL-1β, nitrite, aortic iNOS expression, and vascular dysfunction. In a PI permeability assay, cell lines derived from acute myeloid leukemia were most sensitive to the cytotoxic effects of CMCE. Analysis of Sub-G1 phase, Annexin V-PI positivity, loss of mitochondrial membrane potential, increased caspase-3, and PARP-1 activation confirmed CMCE induced apoptosis in HL-60 cells. IRAK inhibition also sensitized HL-60 cells to CMCE induced cytotoxicity. The present study defines the mechanism underlying the action of CMCE and suggests a therapeutic potential for its use in sepsis and leukemia.

  20. Characterization of three mitogen-activated protein kinases (MAPK) genes reveals involvement of ERK and JNK, not p38 in defense against bacterial infection in Yesso scallop Patinopecten yessoensis.

    PubMed

    Sun, Yan; Zhang, Lingling; Zhang, Meiwei; Li, Ruojiao; Li, Yangping; Hu, Xiaoli; Wang, Shi; Bao, Zhenmin

    2016-07-01

    Mitogen-activated protein kinases (MAPKs) are protein Ser/Thr kinases that play a vital role in innate immune responses by converting extracellular stimuli into a wide range of cellular responses. Although MAPKs have been extensively studied in various vertebrates and invertebrates, our current understanding of MAPK signaling cascade in scallop is in its infancy. In this study, three MAPK genes (PyERK, PyJNK, and Pyp38) were identified from Yesso scallop Patinopecten yessoensis. The open reading frame of PyERK, PyJNK, and Pyp38 was 1104, 1227, and 1104 bp, encoding 367, 408, and 367 amino acids, respectively. Conservation in some splicing sites was revealed across the three PyMAPKs, suggesting the common descent of MAPKs genes. The expression profiles of PyMAPKs over the course of ten different developmental stages showed that they had different expression patterns. In adult scallops, PyMAPKs were primarily expressed in muscles, hemocytes, gill, and mantle. To gain insights into their role in innate immunity, we investigated their expression profiles after infection with Gram-positive bacteria (Micrococcus luteus) and Gram-negative bacteria (Vibrio anguillarum). Significant difference in gene expression was only found in PyERK and PyJNK, but not Pyp38, suggesting Pyp38 may not participate in immune response to bacterial infection. Besides, PyERK and PyJNK exhibited more drastic change against the invasion of V. anguillarum than M. luteus, suggesting they could be more sensitive to Gram-negative bacteria than Gram-positive bacteria. This study provides valuable resource for elucidating the role of MAPK signal pathway in bivalve innate immune response.

  1. QKI-5 suppresses cyclin D1 expression and proliferation of oral squamous cell carcinoma cells via MAPK signalling pathway.

    PubMed

    Fu, X; Feng, Y

    2015-05-01

    Oral squamous cell carcinoma (OSCC) is one of the most frequently occurring malignancies in the world. The RNA-binding protein quaking (QKI) is a newly identified tumour suppressor in multiple cancers, but its role in OSCC is currently unknown. The purpose of the present study was to clarify the relationship between QKI expression and OSCC development. We found QKI-5 expression to be significantly decreased in the oral cancer cell line CAL-27. QKI-5 overexpression also reduced the proliferation of CAL-27 cells, which correlated with cyclin D1. This regulative function of QKI-5 occurs by modulating the phosphorylation level of the mitogen-activated protein kinase (MAPK) pathway. Therefore this study shows that underexpression of tumour suppressor QKI-5 could activate the MAPK pathway and contribute to uncontrolled cyclin D1 expression, thus resulting in increased proliferation of oral cancer cells.

  2. Attenuation of the macrophage inflammatory activity by TiO₂ nanotubes via inhibition of MAPK and NF-κB pathways.

    PubMed

    Neacsu, Patricia; Mazare, Anca; Schmuki, Patrik; Cimpean, Anisoara

    2015-01-01

    Biomaterial implantation in a living tissue triggers the activation of macrophages in inflammatory events, promoting the transcription of pro-inflammatory mediator genes. The initiation of macrophage inflammatory processes is mainly regulated by signaling proteins of mitogen-activated protein kinase (MAPK) and by nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways. We have previously shown that titania nanotubes modified Ti surfaces (Ti/TiO2) mitigate the immune response, compared with flat Ti surfaces; however, little is known regarding the underlying mechanism. Therefore, the aim of this study is to investigate the mechanism(s) by which this nanotopography attenuates the inflammatory activity of macrophages. Thus, we analyzed the effects of TiO2 nanotubes on the activation of MAPK and NF-κB signaling pathways in standard and lipopolysacch