Continuous Blood Purification Ameliorates Multiple Organ Failure Through Inhibiting the Activation of the P38 MAPK Signaling Pathway in a Rat Model.

PubMed

Ling, Lan; Wen, Qian-Kuan; Zhang, Shan-Hong; Zhi, Li-Da; Li, Hong; Li, Gang; Zhang, Wen-Jia

2018-06-07

Multiple organ failure (MOF) is a primary threat to the survival of patients with systemic inflammation. Blood purification is employed in the treatment of MOF, as an artificial kidney or artificial liver. This study focuses on the effects of continuous blood purification (CBP) on ameliorating MOF through regulating the p38 mitogen-activated protein kinase (MAPK) signaling pathway in a rat model. A rat model of MOF was successfully established by endotoxin injection after hemorrhagic shock resuscitation. The mRNA expressions of inducible nitric oxide synthase (iNOS) and p38 MAPK of liver, kidney, and lung tissues in each group were measured by RT-qPCR at each measuring time point. To evaluate the activation of p38 MAPK signaling pathway, protein levels of phosphorylated p38 (p-p38) MAPK and p38 MAPK was measured by western blot analysis. The serum levels of nitric oxide and TNF-α were determined. After CBP treatment, the levels of SGPT, SGOT, Cr, and BUN were significantly declined, while the PaO2 value was increased. Expressions of p38 MAPK mRNA, iNOS mRNA, p-p38 MAPK protein and p38 MAPK protein, and nitric oxide and TNF-α levels were markedly elevated in MOF, an effect blunted by CPB. Meanwhile, pathological sections of liver, kidney, and lung tissues after CPB treatment ameliorated swelling and inflammation. Our study proved that CBP could downregulate the p38 MAPK signaling pathway, suppress iNOS expression, reduced the serum levels of nitric oxide and TNF-α, thus ameliorate symptom of MOF. © 2018 The Author(s). Published by S. Karger AG, Basel.

Ras Signaling Regulates Stem Cells and Amelogenesis in the Mouse Incisor.

PubMed

Zheng, X; Goodwin, A F; Tian, H; Jheon, A H; Klein, O D

2017-11-01

The role of Ras signaling during tooth development is poorly understood. Ras proteins-which are activated by many upstream pathways, including receptor tyrosine kinase cascades-signal through multiple effectors, such as the mitogen-activated protein kinase (MAPK) and PI3K pathways. Here, we utilized the mouse incisor as a model to study how the MAPK and PI3K pathways regulate dental epithelial stem cells and amelogenesis. The rodent incisor-which grows continuously throughout the life of the animal due to the presence of epithelial and mesenchymal stem cells-provides a model for the study of ectodermal organ renewal and regeneration. Utilizing models of Ras dysregulation as well as inhibitors of the MAPK and PI3K pathways, we found that MAPK and PI3K regulate dental epithelial stem cell activity, transit-amplifying cell proliferation, and enamel formation in the mouse incisor.

Role of human amnion-derived mesenchymal stem cells in promoting osteogenic differentiation by influencing p38 MAPK signaling in lipopolysaccharide -induced human bone marrow mesenchymal stem cells

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

Wang, Yuli; Wu, Hongxia; Shen, Ming

Periodontitis is a chronic inflammatory disease induced by bacterial pathogens, which not only affect connective tissue attachments but also cause alveolar bone loss. In this study, we investigated the anti-inflammatory effects of Human amnion-derived mesenchymal stem cells (HAMSCs) on human bone marrow mesenchymal stem cells (HBMSCs) under lipopolysaccharide (LPS)-induced inflammatory conditions. Proliferation levels were measured by flow cytometry and immunofluorescence staining of 5-ethynyl-2′-deoxyuridine (EdU). Osteoblastic differentiation and mineralization were investigated using chromogenic alkaline phosphatase activity (ALP) activity substrate assays, Alizarin red S staining, and RT-PCR analysis of HBMSCs osteogenic marker expression. Oxidative stress induced by LPS was investigated by assayingmore » reactive oxygen species (ROS) level and superoxide dismutase (SOD) activity. Here, we demonstrated that HAMSCs increased the proliferation, osteoblastic differentiation, and SOD activity of LPS-induced HBMSCs, and down-regulated the ROS level. Moreover, our results suggested that the activation of p38 MAPK signal transduction pathway is essential for reversing the LPS-induced bone-destructive processes. SB203580, a selective inhibitor of p38 MAPK signaling, significantly suppressed the anti-inflammatory effects in HAMSCs. In conclusion, HAMSCs show a strong potential in treating inflammation-induced bone loss by influencing p38 MAPK signaling. - Highlights: • LPS inhibites osteogenic differentiation in HBMSCs via suppression of p38 MAPK signaling pathway. • HAMSCs promote LPS-induced HBMSCs osteogenic differentiation through p38 MAPK signaling pathway. • HAMSCs reverse LPS-induced oxidative stress in LPS-induced HBMSCs through p38 MAPK signaling pathway.« less

Mitogen-activated protein kinase phosphatase-1: a critical phosphatase manipulating mitogen-activated protein kinase signaling in cardiovascular disease (review).

PubMed

Li, Chang-Yi; Yang, Ling-Chao; Guo, Kai; Wang, Yue-Peng; Li, Yi-Gang

2015-04-01

Mitogen-activated protein kinase (MAPK) cascades are important players in the overall representation of cellular signal transduction pathways, and the deregulation of MAPKs is involved in a variety of diseases. The activation of MAPK signals occurs through phosphorylation by MAPK kinases at conserved threonine and tyrosine (Thr-Xaa-Tyr) residues. The mitogen-activated protein kinase phosphatases (MKPs) are a major part of the dual-specificity family of phosphatases and specifically inactivate MAPKs by dephosphorylating both phosphotyrosine and phosphoserine/phosphothreonine residues within the one substrate. MAPKs binding to MKPs can enhance MKP stability and activity, providing an important negative-feedback control mechanism that limits the MAPK cascades. In recent years, accumulating and compelling evidence from studies mainly employing cultured cells and mouse models has suggested that the archetypal MKP family member, MKP-1, plays a pivotal role in cardiovascular disease as a major negative modulator of MAPK signaling pathways. In the present review, we summarize the current knowledge on the pathological properties and the regulation of MKP-1 in cardiovascular disease, which may provide valuable therapeutic options.

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

PubMed Central

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

2014-01-01

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

Involvement of PI3K/Akt and p38 MAPK in the induction of COX-2 expression by bacterial lipopolysaccharide in murine adrenocortical cells.

PubMed

Mercau, M E; Astort, F; Giordanino, E F; Martinez Calejman, C; Sanchez, R; Caldareri, L; Repetto, E M; Coso, O A; Cymeryng, C B

2014-03-25

Previous studies from our laboratory demonstrated the involvement of COX-2 in the stimulation of steroid production by LPS in murine adrenocortical Y1 cells, as well as in the adrenal cortex of male Wistar rats. In this paper we analyzed signaling pathways involved in the induction of this key regulatory enzyme in adrenocortical cells and demonstrated that LPS triggers an increase in COX-2 mRNA levels by mechanisms involving the stimulation of reactive oxygen species (ROS) generation and the activation of p38 MAPK and Akt, in addition to the previously demonstrated increase in NFκB activity. In this sense we showed that: (1) inhibition of p38 MAPK or PI3K/Akt (pharmacological or molecular) prevented the increase in COX-2 protein levels by LPS, (2) LPS induced p38 MAPK and Akt phosphorylation, (3) antioxidant treatment blocked the effect of LPS on p38 MAPK phosphorylation and in COX-2 protein levels, (4) PI3K inhibition with LY294002 prevented p38 MAPK phosphorylation and, (5) the activity of an NFκB reporter was decreased by p38 MAPK or PI3K inhibition. These results suggest that activation of both p38 MAPK and PI3K/Akt pathways promote the stimulation of NFκB activity and that PI3K/Akt activity might regulate both p38 MAPK and NFκB signaling pathways. In summary, in this study we showed that in adrenal cells, LPS induces COX-2 expression by activating p38 MAPK and PI3K/Akt signaling pathways and that both pathways converge in the modulation of NFκB transcriptional activity. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

LncMAPK6 drives MAPK6 expression and liver TIC self-renewal.

PubMed

Huang, Guanqun; Jiang, Hui; He, Yueming; Lin, Ye; Xia, Wuzheng; Luo, Yuanwei; Liang, Min; Shi, Boyun; Zhou, Xinke; Jian, Zhixiang

2018-05-15

Liver tumor initiating cells (TICs) have self-renewal and differentiate capacities, and largely contribute to tumor initiation, metastasis and drug resistance. MAPK signaling is a critical pathway in many biological processes, while its role in liver TICs hasn't been explored. Online-available dataset was used for unbiased screening. Liver TICs were examined CD133 FACS or oncosphere formation. TIC self-renewal was detected by oncosphere formation and tumor initiation assay. LncRNA function was detected by loss of function or gain of function assays. The molecular mechanism of lncRNA was explored by RNA pulldown, RNA immunoprecipitation, ChIP, western blot and double FISH. Here, we examined the expression profiles of MAPK components (MAPKs, MAP2Ks, MAP3Ks, MAP4Ks), and found MAPK6 is most highly expressed in liver cancer samples. Moreover, a divergent lncRNA (long noncoding RNA) of MAPK6, termed lncMAPK6 here, is also overexpressed along with liver tumorigenesis. LncMAPK6 promotes liver tumor propagation and TIC self-renewal through MAPK6. LncMAPK6 interacts with and recruits RNA polymerase II to MAPK6 promoter, and finally activates the transcription of MAPK6. Through MAPK6 transcriptional regulation, lncMAPK6 drives MARK signaling activation. LncMAPK6-MAPK6 pathway can be used for liver TIC targeting. Altogether, lncMAPK6 promotes MARK signaling and the self-renewal of liver TICs through MAPK6 expression. MAPK6 was the most highly expressed MAPK component in liver cancer and liver TICs and lncMAPK6 participated in the transcriptional regulation of MAPK6in cis. This work revealed the importance role of MAPK signaling in liver TIC self-renewal and added a new layer for liver TIC and MAPK6 expression regulation.

Sodium appetite elicited by low-sodium diet is dependent on p44/42 mitogen-activated protein kinase (extracellular signal-regulated kinase 1/2) activation in the brain.

PubMed

Monteiro, L R N; Marangon, P B; Elias, L L K; Reis, L C; Antunes-Rodrigues, J; Mecawi, A S

2017-09-01

Sodium appetite is regulated by several signalling molecules, among which angiotensin II (Ang II) serves as a key driver of robust salt intake by binding to Ang II type 1 receptors (AT1R) in several regions in the brain. The activation of these receptors recruits the mitogen-activated protein kinase (MAPK) pathway, which has previously been linked to Ang II-induced increases in sodium appetite. Thus, we addressed the involvement of MAPK signalling in the induction of sodium appetite after 4 days of low-sodium diet consumption. An increase in extracellular signal-regulated kinase (ERK) phosphorylation in the laminae terminalis and mediobasal hypothalamus was observed after low-sodium diet consumption. This response was reduced by i.c.v. microinjection of an AT1R antagonist into the laminae terminalis but not the hypothalamus. This result indicates that low-sodium diet consumption activates the MAPK pathway via Ang II/AT1R signalling on the laminae terminalis. On the other hand, activation of the MAPK pathway in the mediobasal hypothalamus after low-sodium diet consumption appears to involve another extracellular mediator. We also evaluated whether a low-sodium diet could increase the sensitivity for Ang II in the brain and activate the MAPK pathway. However, i.c.v. injection of Ang II increased ERK phosphorylation on the laminae terminalis and mediobasal hypothalamus; this increase achieved a response magnitude similar to those observed in both the normal and low-sodium diet groups. These data indicate that low-sodium diet consumption for 4 days is insufficient to change the ERK phosphorylation response to Ang II in the brain. To investigate whether the MAPK pathway is involved in sodium appetite after low-sodium diet consumption, we performed i.c.v. microinjections of a MAPK pathway inhibitor (PD98059). PD98059 inhibited both saline and water intake after low-sodium diet consumption. Thus, the MAPK pathway is involved in promoting the sodium appetite after low-sodium diet consumption. © 2017 British Society for Neuroendocrinology.

The Deubiquitinase USP47 Stabilizes MAPK by Counteracting the Function of the N-end Rule ligase POE/UBR4 in Drosophila.

PubMed

Ashton-Beaucage, Dariel; Lemieux, Caroline; Udell, Christian M; Sahmi, Malha; Rochette, Samuel; Therrien, Marc

2016-08-01

RAS-induced MAPK signaling is a central driver of the cell proliferation apparatus. Disruption of this pathway is widely observed in cancer and other pathologies. Consequently, considerable effort has been devoted to understanding the mechanistic aspects of RAS-MAPK signal transmission and regulation. While much information has been garnered on the steps leading up to the activation and inactivation of core pathway components, comparatively little is known on the mechanisms controlling their expression and turnover. We recently identified several factors that dictate Drosophila MAPK levels. Here, we describe the function of one of these, the deubiquitinase (DUB) USP47. We found that USP47 acts post-translationally to counteract a proteasome-mediated event that reduces MAPK half-life and thereby dampens signaling output. Using an RNAi-based genetic interaction screening strategy, we identified UBC6, POE/UBR4, and UFD4, respectively, as E2 and E3 enzymes that oppose USP47 activity. Further characterization of POE-associated factors uncovered KCMF1 as another key component modulating MAPK levels. Together, these results identify a novel protein degradation module that governs MAPK levels. Given the role of UBR4 as an N-recognin ubiquitin ligase, our findings suggest that RAS-MAPK signaling in Drosophila is controlled by the N-end rule pathway and that USP47 counteracts its activity.

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

PubMed

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

2012-06-01

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

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

PubMed Central

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

2012-01-01

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

Non-Smad signaling pathways.

PubMed

Mu, Yabing; Gudey, Shyam Kumar; Landström, Maréne

2012-01-01

Transforming growth factor-beta (TGFβ) is a key regulator of cell fate during embryogenesis and has also emerged as a potent driver of the epithelial-mesenchymal transition during tumor progression. TGFβ signals are transduced by transmembrane type I and type II serine/threonine kinase receptors (TβRI and TβRII, respectively). The activated TβR complex phosphorylates Smad2 and Smad3, converting them into transcriptional regulators that complex with Smad4. TGFβ also uses non-Smad signaling pathways such as the p38 and Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways to convey its signals. Ubiquitin ligase tumor necrosis factor (TNF)-receptor-associated factor 6 (TRAF6) and TGFβ-associated kinase 1 (TAK1) have recently been shown to be crucial for the activation of the p38 and JNK MAPK pathways. Other TGFβ-induced non-Smad signaling pathways include the phosphoinositide 3-kinase-Akt-mTOR pathway, the small GTPases Rho, Rac, and Cdc42, and the Ras-Erk-MAPK pathway. Signals induced by TGFβ are tightly regulated and specified by post-translational modifications of the signaling components, since they dictate the subcellular localization, activity, and duration of the signal. In this review, we discuss recent findings in the field of TGFβ-induced responses by non-Smad signaling pathways.

Regulation of mGlu4 metabotropic glutamate receptor signaling by type-2 G-protein coupled receptor kinase (GRK2).

PubMed

Iacovelli, L; Capobianco, L; Iula, M; Di Giorgi Gerevini, V; Picascia, A; Blahos, J; Melchiorri, D; Nicoletti, F; De Blasi, A

2004-05-01

We examined the role of G-protein coupled receptor kinase-2 (GRK2) in the homologous desensitization of mGlu4 metabotropic glutamate receptors transiently expressed in human embryonic kidney (HEK) 293 cells. Receptor activation with the agonist l-2-amino-4-phosphonobutanoate (l-AP4) stimulated at least two distinct signaling pathways: inhibition of cAMP formation and activation of the mitogen-activated protein kinase (MAPK) pathway [assessed by Western blot analysis of phosphorylated extracellular signal-regulated kinase (ERK) 1 and 2]. Activation of both pathways was attenuated by pertussis toxin. Overexpression of GRK2 (but not GRK4) largely attenuated the stimulation of the MAPK pathway by l-AP4, whereas it slightly potentiated the inhibition of FSK-stimulated cAMP formation. Transfection with a kinase-dead mutant of GRK2 (GRK2-K220R) or with the C-terminal fragment of GRK2 also reduced the mGlu4-mediated stimulation of MAPK, suggesting that GRK2 binds to the Gbetagamma subunits to inhibit signal propagation toward the MAPK pathway. This was confirmed by the evidence that GRK2 coimmunoprecipitated with Gbetagamma subunits in an agonist-dependent manner. Finally, neither GRK2 nor its kinase-dead mutant had any effect on agonist-induced mGlu4 receptor internalization in HEK293 cells transiently transfected with GFP-tagged receptors. Agonist-dependent internalization was instead abolished by a negative-dominant mutant of dynamin, which also reduced the stimulation of MAPK pathway by l-AP4. We speculate that GRK2 acts as a "switch molecule" by inhibiting the mGlu4 receptor-mediated stimulation of MAPK and therefore directing the signal propagation toward the inhibition of adenylyl cyclase.

Hypoxia enhances periodontal ligament stem cell proliferation via the MAPK signaling pathway.

PubMed

He, Y; Jian, C X; Zhang, H Y; Zhou, Y; Wu, X; Zhang, G; Tan, Y H

2016-11-21

There is high incidence of periodontal disease in high-altitude environments; hypoxia may influence the proliferation and clone-forming ability of periodontal ligament stem cells (PDLSCs). The MAPK signaling pathway is closely correlated with cell proliferation, differentiation, and apoptosis. Thus, we isolated and cultured PDLSCs under hypoxic conditions to clarify the impact of hypoxia on PDLSC proliferation and the underlying mechanism. PDLSCs were separated and purified by the limiting dilution method and identified by flow cytometry. PDLSCs were cultured under hypoxic or normoxic conditions to observe their cloning efficiency. PDLSC proliferation at different oxygen concentrations was evaluated by MTT assay. Expression of p38/MAPK and MAPK/ERK signaling pathway members was detected by western blotting. Inhibitors for p38/MAPK or ERK were applied to PDLSCs to observe their impacts on clone formation and proliferation. Isolated PDLSCs exhibited typical stem cell morphological characteristics, strong abilities of globular clone formation and proliferation, and upregulated expression of mesenchymal stem cell markers. Stem cell marker expression was not statistically different between PDLSCs cultured under hypoxia and normoxia (P > 0.05). The clone number in the hypoxia group was significantly higher than that in the control (P < 0.05). PDLSC proliferation under hypoxia was higher than that of the control (P < 0.001). p38 and ERK1/2 phosphorylation in hypoxic PDLSCs was markedly enhanced compared to that in the control (P < 0.05). Either P38/MAPK inhibitor or ERK inhibitor treatment reduced clone formation and proliferation. Therefore, hypoxia enhanced PDLSC clone formation and proliferation by activating the p38/MAPK and ERK/MAPK signaling pathways.

Conservation of protein abundance patterns reveals the regulatory architecture of the EGFR-MAPK pathway

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

Shi, T.; Niepel, M.; McDermott, J. E.

It is not known whether cancer cells generally show quantitative differences in the expression of signaling pathway proteins that could dysregulate signal transduction. To explore this issue, we first defined the primary components of the EGF-MAPK pathway in normal human mammary epithelial cells, identifying 16 core proteins and 10 feedback regulators. We then quantified their absolute abundance across a panel of normal and cancer cell lines. We found that core pathway proteins were expressed at very similar levels across all cell types. In contrast, the EGFR and transcriptionally controlled feedback regulators were expressed at highly variable levels. The absolute abundancemore » of most core pathway proteins was between 50,000- 70,000 copies per cell, but the adaptors SOS1, SOS2, and GAB1 were found at far lower levels (2,000-5,000 per cell). MAPK signaling showed saturation in all cells between 3,000-10,000 occupied EGFR, consistent with the idea that low adaptor levels limit signaling. Our results suggest that the core MAPK pathway is essentially invariant across different cell types, with cell- specific differences in signaling likely due to variable levels of feedback regulators. The low abundance of adaptors relative to the EGFR could be responsible for previous observation of saturable signaling, endocytosis, and high affinity EGFR.« less

Involvement of PI3K/AKT and MAPK Pathways for TNF-α Production in SiHa Cervical Mucosal Epithelial Cells Infected with Trichomonas vaginalis.

PubMed

Yang, Jung-Bo; Quan, Juan-Hua; Kim, Ye-Eun; Rhee, Yun-Ee; Kang, Byung-Hyun; Choi, In-Wook; Cha, Guang-Ho; Yuk, Jae-Min; Lee, Young-Ha

2015-08-01

Trichomonas vaginalis; induces proinflammation in cervicovaginal mucosal epithelium. To investigate the signaling pathways in TNF-α production in cervical mucosal epithelium after T. vaginalis infection, the phosphorylation of PI3K/AKT and MAPK pathways were evaluated in T. vaginalis-infected SiHa cells in the presence and absence of specific inhibitors. T. vaginalis increased TNF-α production in SiHa cells, in a parasite burden-dependent and incubation time-dependent manner. In T. vaginalis-infected SiHa cells, AKT, ERK1/2, p38 MAPK, and JNK were phosphorylated from 1 hr after infection; however, the phosphorylation patterns were different from each other. After pretreatment with inhibitors of the PI3K/AKT and MAPK pathways, TNF-α production was significantly decreased compared to the control; however, TNF-α reduction patterns were different depending on the type of PI3K/MAPK inhibitors. TNF-α production was reduced in a dose-dependent manner by treatment with wortmannin and PD98059, whereas it was increased by SP600125. These data suggested that PI3K/AKT and MAPK signaling pathways are important in regulation of TNF-α production in cervical mucosal epithelial SiHa cells. However, activation patterns of each pathway were different from the types of PI3K/MAPK pathways.

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…

An Interdisciplinary Approach for Designing Kinetic Models of the Ras/MAPK Signaling Pathway.

PubMed

Reis, Marcelo S; Noël, Vincent; Dias, Matheus H; Albuquerque, Layra L; Guimarães, Amanda S; Wu, Lulu; Barrera, Junior; Armelin, Hugo A

2017-01-01

We present in this article a methodology for designing kinetic models of molecular signaling networks, which was exemplarily applied for modeling one of the Ras/MAPK signaling pathways in the mouse Y1 adrenocortical cell line. The methodology is interdisciplinary, that is, it was developed in a way that both dry and wet lab teams worked together along the whole modeling process.

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

PubMed Central

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

2011-01-01

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

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

PubMed

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

2012-07-19

Activating mutations in the RAS family or BRAF frequently occur in many types of human cancers but are rarely detected in breast tumors. However, activation of the RAS-RAF-MEK-ERK MAPK pathway is commonly observed in human breast cancers, suggesting that other genetic alterations lead to activation of this signaling pathway. To identify breast cancer oncogenes that activate the MAPK pathway, we screened a library of human kinases for their ability to induce anchorage-independent growth in a derivative of immortalized human mammary epithelial cells (HMLE). We identified p21-activated kinase 1 (PAK1) as a kinase that permitted HMLE cells to form anchorage-independent colonies. PAK1 is amplified in several human cancer types, including 30--33% of breast tumor samples and cancer cell lines. The kinase activity of PAK1 is necessary for PAK1-induced transformation. Moreover, we show that PAK1 simultaneously activates MAPK and MET signaling; the latter via inhibition of merlin. Disruption of these activities inhibits PAK1-driven anchorage-independent growth. These observations establish PAK1 amplification as an alternative mechanism for MAPK activation in human breast cancer and credential PAK1 as a breast cancer oncogene that coordinately regulates multiple signaling pathways, the cooperation of which leads to malignant transformation.

Candida albicans yeast and hyphae are discriminated by MAPK signaling in vaginal epithelial cells.

PubMed

Moyes, David L; Murciano, Celia; Runglall, Manohursingh; Islam, Ayesha; Thavaraj, Selvam; Naglik, Julian R

2011-01-01

We previously reported that a bi-phasic innate immune MAPK response, constituting activation of the mitogen-activated protein kinase (MAPK) phosphatase MKP1 and c-Fos transcription factor, discriminates between the yeast and hyphal forms of Candida albicans in oral epithelial cells (ECs). Since the vast majority of mucosal Candida infections are vaginal, we sought to determine whether a similar bi-phasic MAPK-based immune response was activated by C. albicans in vaginal ECs. Here, we demonstrate that vaginal ECs orchestrate an innate response to C. albicans via NF-κB and MAPK signaling pathways. However, unlike in oral ECs, the first MAPK response, defined by c-Jun transcription factor activation, is delayed until 2 h in vaginal ECs but is still independent of hypha formation. The 'second' or 'late' MAPK response, constituting MKP1 and c-Fos transcription factor activation, is identical to oral ECs and is dependent upon both hypha formation and fungal burdens. NF-κB activation is immediate but independent of morphology. Furthermore, the proinflammatory response in vaginal ECs is different to oral ECs, with an absence of G-CSF and CCL20 and low level IL-6 production. Therefore, differences exist in how C. albicans activates signaling mechanisms in oral and vaginal ECs; however, the activation of MAPK-based pathways that discriminate between yeast and hyphal forms is retained between these mucosal sites. We conclude that this MAPK-based signaling pathway is a common mechanism enabling different human epithelial tissues to orchestrate innate immune responses specifically against C. albicans hyphae.

Effect of aromatase inhibitor letrozole on the proliferation of spermatogonia by regulating the MAPK pathway.

PubMed

Wang, Shunde; Wang, Shuhong; Li, Hang; Li, Xiaoxia; Xie, Menglin; Wen, Jiayu; Li, Meicai; Long, Tengbo

2018-06-01

The molecular mechanism of the aromatase inhibitor letrozole was investigated. It promotes the proliferation of spermatogonia by regulating the mitogen-activated protein kinase (MAPK) pathway. Six different concentrations were selected for letrozole in order to incubate mouse spermatogonia [GC-1 spermatogonia (spg)] for 24, 48 and 72 h, respectively. Cell Counting Kit-8 (CCK-8) was used to observe the effect of letrozole on the proliferation of GC-1 spg cells, and the effect was further verified by cell plate clone formation assay. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis were used to detect the effects of letrozole on MAPK signaling pathways [Ras/extracellular signal-regulated kinase 1 (ERK1)/c-Myc], proliferation indexes [Ki-67 and proliferating cell nuclear antigen (PCNA)]. Bromodeoxyuridine (BrdU) staining was used to study the effects of letrozole and MAPK signaling pathways on cell proliferation. The results of CCK-8 showed that the proliferation rate of GC-1 spg cells was improved. Study results also revealed a significant increase in letrozole concentration along with the time of action. The results of plate clone formation assay further indicated that letrozole could significantly promote the proliferation capacity of GC-1 spg cells (p<0.05). The results of RT-PCR and western blot analysis confirmed letrozole significantly activated the expression of Ras/ERK1/c-Myc in the classical MAPK pathway. A significant increase was noted in the protein levels of Ki-67 and PCNA (p<0.05). By contrast, inhibition of the MAPK pathway resulted in a significant decrease in the levels of the above indexes (p<0.05). The number of BrdU cells in the letrozole group was also higher than that of the control group, while the number of BrdU-stained cells in the letrozole + MAPK inhibition group showed a significant decrease in comparison to the letrozole group. In conclusion, letrozole activated the MAPK signaling pathway and promoted the proliferation of mouse spermatogonia GC-1 spg cells. The present study provides a theoretical basis for the clinical application of letrozole.

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

PubMed

Tartaglia, Marco; Gelb, Bruce D

2010-12-01

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 toward the dysregulation of this signaling cascade, and major genotype-phenotype correlations. © 2010 New York Academy of Sciences.

Phosphodiesterase inhibitors suppress Lactobacillus casei cell-wall-induced NF-κB and MAPK activations and cell proliferation through protein kinase A--or exchange protein activated by cAMP-dependent signal pathway.

PubMed

Saito, Takekatsu; Sugimoto, Naotoshi; Ohta, Kunio; Shimizu, Tohru; Ohtani, Kaori; Nakayama, Yuko; Nakamura, Taichi; Hitomi, Yashiaki; Nakamura, Hiroyuki; Koizumi, Shoichi; Yachie, Akihiro

2012-01-01

Specific strains of Lactobacillus have been found to be beneficial in treating some types of diarrhea and vaginosis. However, a high mortality rate results from underlying immunosuppressive conditions in patients with Lactobacillus casei bacteremia. Cyclic AMP (cAMP) is a small second messenger molecule that mediates signal transduction. The onset and progression of inflammatory responses are sensitive to changes in steady-state cAMP levels. L. casei cell wall extract (LCWE) develops arteritis in mice through Toll-like receptor-2 signaling. The purpose of this study was to investigate whether intracellular cAMP affects LCWE-induced pathological signaling. LCWE was shown to induce phosphorylation of the nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways and cell proliferation in mice fibroblast cells. Theophylline and phosphodiesterase inhibitor increased intracellular cAMP and inhibited LCWE-induced cell proliferation as well as phosphorylation of NF-κB and MAPK. Protein kinase A inhibitor H89 prevented cAMP-induced MAPK inhibition, but not cAMP-induced NF-κB inhibition. An exchange protein activated by cAMP (Epac) agonist inhibited NF-κB activation but not MAPK activation. These results indicate that an increase in intracellular cAMP prevents LCWE induction of pathological signaling pathways dependent on PKA and Epac signaling.

An algorithm for modularization of MAPK and calcium signaling pathways: comparative analysis among different species.

PubMed

Nayak, Losiana; De, Rajat K

2007-12-01

Signaling pathways are large complex biochemical networks. It is difficult to analyze the underlying mechanism of such networks as a whole. In the present article, we have proposed an algorithm for modularization of signal transduction pathways. Unlike studying a signaling pathway as a whole, this enables one to study the individual modules (less complex smaller units) easily and hence to study the entire pathway better. A comparative study of modules belonging to different species (for the same signaling pathway) has been made, which gives an overall idea about development of the signaling pathways over the taken set of species of calcium and MAPK signaling pathways. The superior performance, in terms of biological significance, of the proposed algorithm over an existing community finding algorithm of Newman [Newman MEJ. Modularity and community structure in networks. Proc Natl Acad Sci USA 2006;103(23):8577-82] has been demonstrated using the aforesaid pathways of H. sapiens.

The Nuclear Dbf2-Related Kinase COT1 and the Mitogen-Activated Protein Kinases MAK1 and MAK2 Genetically Interact to Regulate Filamentous Growth, Hyphal Fusion and Sexual Development in Neurospora crassa

PubMed Central

Maerz, Sabine; Ziv, Carmit; Vogt, Nico; Helmstaedt, Kerstin; Cohen, Nourit; Gorovits, Rena; Yarden, Oded; Seiler, Stephan

2008-01-01

Ndr kinases, such as Neurospora crassa COT1, are important for cell differentiation and polar morphogenesis, yet their input signals as well as their integration into a cellular signaling context are still elusive. Here, we identify the cot-1 suppressor gul-4 as mak-2 and show that mutants of the gul-4/mak-2 mitogen-activated protein (MAP) kinase pathway suppress cot-1 phenotypes along with a concomitant reduction in protein kinase A (PKA) activity. Furthermore, mak-2 pathway defects are partially overcome in a cot-1 background and are associated with increased MAK1 MAPK signaling. A comparative characterization of N. crassa MAPKs revealed that they act as three distinct modules during vegetative growth and asexual development. In addition, common functions of MAK1 and MAK2 signaling during maintenance of cell-wall integrity distinguished the two ERK-type pathways from the p38-type OS2 osmosensing pathway. In contrast to separate functions during vegetative growth, the concerted activity of the three MAPK pathways is essential for cell fusion and for the subsequent formation of multicellular structures that are required for sexual development. Taken together, our data indicate a functional link between COT1 and MAPK signaling in regulating filamentous growth, hyphal fusion, and sexual development. PMID:18562669

In vivo phosphorylation of WRKY transcription factor by MAPK.

PubMed

Ishihama, Nobuaki; Adachi, Hiroaki; Yoshioka, Miki; Yoshioka, Hirofumi

2014-01-01

Plants activate signaling networks in response to diverse pathogen-derived signals, facilitating transcriptional reprogramming through mitogen-activated protein kinase (MAPK) cascades. Identification of phosphorylation targets of MAPK and in vivo detection of the phosphorylated substrates are important processes to elucidate the signaling pathway in plant immune responses. We have identified a WRKY transcription factor, which is phosphorylated by defense-related MAPKs, SIPK and WIPK. Recent evidence demonstrated that some group I WRKY transcription factors, which contain a conserved motif in the N-terminal region, are activated by MAPK-dependent phosphorylation. In this chapter, we describe protocols for preparation of anti-phosphopeptide antibodies, detection of activated MAPKs using anti-phospho-MAPK antibody, and activated WRKY using anti-phospho-WRKY antibody, respectively.

Role of MAPK/MNK1 signaling in virus replication.

PubMed

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

2018-06-01

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

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

USDA-ARS?s Scientific Manuscript database

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...

Porphyromonas gingivalis lipopolysaccharide activates canonical Wnt/β-catenin and p38 MAPK signalling in stem cells from the apical papilla.

PubMed

Wang, Jia; Dai, Jiewen; Liu, Bin; Gu, Shensheng; Cheng, Lan; Liang, Jingping

2013-12-01

As dental precursor cells, stem cells from the apical papilla (SCAP) are capable of forming roots and undergoing apexogenesis, which are impaired upon exposure to bacterial infection. Porphyromonas gingivalis is a common Gram-negative bacterium that is involved in pulpal and periapical infection. The purpose of this study was to investigate the effects of P. gingivalis lipopolysaccharide (LPS) on the Wnt/β-catenin and p38 mitogen-activated protein kinase (MAPK) signalling pathways in SCAP. As indicated by the IL-1β and TNF-α mRNA levels, P. gingivalis LPS induced the expression of pro-inflammatory cytokines in a dose-dependent manner. In addition, activation of the p38 MAPK and Wnt/β-catenin pathways was confirmed by the augmentation of phospho-p38 and β-catenin protein expression and increased expression of c-myc and cyclin D1 mRNA. Despite no significant increase in β-catenin mRNA expression, increased phosphorylation of glycogen synthase kinase (GSK)-3β suggested that GSK-3β was responsible for the accumulation of β-catenin in the cytoplasm and translocation to the nucleus. Previous studies have shown that GSK-3β plays a critical role in crosstalk between the Wnt/β-catenin and p38 MAPK pathways. In the present study, we showed that the level of p38 phosphorylation decreased upon pretreatment with a p38 MAPK inhibitor for 1 h before stimulating SCAP with 10 μg/ml P. gingivalis LPS. However, the levels of GSK-3β and β-catenin phosphorylation in the cytoplasm and nucleus were not significantly altered. Our results suggest that the p38 MAPK and canonical Wnt/β-catenin signalling pathways are activated by P. gingivalis LPS in SCAP, but we have no evidence that p38 MAPK is upstream of GSK-3β in the Wnt/β-catenin signalling pathway.

p38 MAPK signal pathway involved in anti-inflammatory effect of Chaihu-Shugan-San and Shen-ling-bai-zhu-San on hepatocyte in non-alcoholic steatohepatitis rats.

PubMed

Yang, QinHe; Xu, YongJian; Feng, GaoFei; Hu, ChaoFeng; Zhang, YuPei; Cheng, ShaoBing; Wang, YanPing; Gong, XiangWen

2014-01-01

Traditional Chinese Medicine (TCM), has over thousands-of-years history of use. Chaihu-Shugan-San (CSS), and Shen-ling-bai-zhu-San (SLBZS), are famous traditional Chinese herbal medicine formulas, which have been used in China, for the treatment of many chronic diseases. This study investigated the anti-inflammatory effects of CSS and SLBZS on signaling molecules involved in p38 mitogen-activated protein kinase (p38 MAPK), pathway on hepatocytes of non-alcoholic steatohepatitis (NASH), rats induced by high fat diet. SD male rats were randomly divided into 8 groups: negative control group, model control group, high (9.6g/kg/day)/low (3.2g/kg/day)-dose CSS group, high (30g/kg/day)/low (10g/kg/day)-dose SLBZS group, high (39.6g/kg/day)/low (13.2g/kg/day)-dose integrated group. The rats of NASH model were induced by feeding a high-fat diet. After 16, wks, Hepatocytes were isolated from 6, rats in each group by collagenase perfusion. The liver histopathological changes and serum inflammatory cytokines TNF-α, IL-6 were determined. The proteins of TLR4, phosphor-p38 MAPK and p38 MAPK involved in p38 MAPK signal pathway were assayed. The statistical data indicated the NASH model rats reproduced typical histopathological features of NASH in human. CSS and SLBZS ameliorated lipid metabolic disturbance, attenuated NASH progression, decreased the levels of TNF-α and IL-6 in serum, as well as inhibited TLR4 protein expression, p38 MAPK phosphorylation, and activation of p38 MAPK. In conclusion, CSS and SLBZS might work as a significant anti-inflammatory effect on hepatocyte of NASH by inhibiting the activation of TLR4, p-p38 MAPK and p38 MAPK involved in p38 MAPK signal pathway. To some extent, CSS and SLBZS may be a potential alternative and complementary medicine to protect against liver injury, alleviate the inflammation reaction, moderate NASH progression.

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

Penehyclidine hydrochloride regulates mitochondrial dynamics and apoptosis through p38MAPK and JNK signal pathways and provides cardioprotection in rats with myocardial ischemia-reperfusion injury.

PubMed

Feng, Min; Wang, Lirui; Chang, Siyuan; Yuan, Pu

2018-05-31

The potential mechanism of penehyclidine hydrochloride (PHC) against myocardial ischemia-reperfusion (I/R) injury has not been fully elucidated. The aim of the present study was to reveal whether mitochondrial dynamics, apoptosis, and MAPKs were involved in the cardioprotective effect of this drug on myocardial I/R injury. Ninety healthy adult male Wistar rats were separately pretreated with normal saline (0.9%); PHC; and signal pathway blockers of MAPKs, Drp1, and Bcl-2. Coronary artery ligation and subsequent reperfusion were performed to induce myocardial I/R injury. Echocardiography was performed. Myocardial enzymes and oxidative stress markers were detected. Myocardial cell apoptotic rates and infarct sizes were measured. Mitochondrial function was evaluated. Expression levels of MAPKs, mitochondria regulatory proteins (Drp1, Mfn1/2), and apoptosis-related proteins (Bcl-2, Bax) were determined. PHC pretreatment improved myocardial abnormalities (dysfunction, injury, infarct size, and apoptotic rate), mitochondrial abnormalities (dysfunction and fission), and excessive oxidative stress and inhibited the activities of p38MAPK and JNK signal pathways in rats with myocardial I/R injury (P < 0.05). Additionally, p38MAPK and JNK blockers (SB239063 and SP600125, respectively) had an effect on rats same as that of PHC. Although Drp1 blocker (Mdivi-1) showed a similar cardioprotective effect (P < 0.05), it did not affect the expression of MAPKs and apoptosis-related proteins (P > 0.05). In addition, Bcl-2 blocker (ABT-737) caused a high expression of Drp1 and a low expression of Mfn1/2 (P < 0.05). PHC regulated mitochondrial dynamics and apoptosis through p38MAPK and JNK signal pathways and provided cardioprotection in rats with myocardial I/R injury. Copyright © 2018 Elsevier B.V. All rights reserved.

TGF-β and BMP Signaling in Osteoblast Differentiation and Bone Formation

PubMed Central

Chen, Guiqian; Deng, Chuxia; Li, Yi-Ping

2012-01-01

Transforming growth factor-beta (TGF-β)/bone morphogenic protein (BMP) signaling is involved in a vast majority of cellular processes and is fundamentally important throughout life. TGF-β/BMPs have widely recognized roles in bone formation during mammalian development and exhibit versatile regulatory functions in the body. Signaling transduction by TGF-β/BMPs is specifically through both canonical Smad-dependent pathways (TGF-β/BMP ligands, receptors and Smads) and non-canonical Smad-independent signaling pathway (e.g. p38 mitogen-activated protein kinase pathway, MAPK). Following TGF-β/BMP induction, both the Smad and p38 MAPK pathways converge at the Runx2 gene to control mesenchymal precursor cell differentiation. The coordinated activity of Runx2 and TGF-β/BMP-activated Smads is critical for formation of the skeleton. Recent advances in molecular and genetic studies using gene targeting in mice enable a better understanding of TGF-β/BMP signaling in bone and in the signaling networks underlying osteoblast differentiation and bone formation. This review summarizes the recent advances in our understanding of TGF-β/BMP signaling in bone from studies of genetic mouse models and human diseases caused by the disruption of TGF-β/BMP signaling. This review also highlights the different modes of cross-talk between TGF-β/BMP signaling and the signaling pathways of MAPK, Wnt, Hedgehog, Notch, and FGF in osteoblast differentiation and bone formation. PMID:22298955

Immunolocalization of dually phosphorylated MAPKs in dividing root meristem cells of Vicia faba, Pisum sativum, Lupinus luteus and Lycopersicon esculentum.

PubMed

Winnicki, Konrad; Żabka, Aneta; Bernasińska, Joanna; Matczak, Karolina; Maszewski, Janusz

2015-06-01

In plants, phosphorylated MAPKs display constitutive nuclear localization; however, not all studied plant species show co-localization of activated MAPKs to mitotic microtubules. The mitogen-activated protein kinase (MAPK) signaling pathway is involved not only in the cellular response to biotic and abiotic stress but also in the regulation of cell cycle and plant development. The role of MAPKs in the formation of a mitotic spindle has been widely studied and the MAPK signaling pathway was found to be indispensable for the unperturbed course of cell division. Here we show cellular localization of activated MAPKs (dually phosphorylated at their TXY motifs) in both interphase and mitotic root meristem cells of Lupinus luteus, Pisum sativum, Vicia faba (Fabaceae) and Lycopersicon esculentum (Solanaceae). Nuclear localization of activated MAPKs has been found in all species. Co-localization of these kinases to mitotic microtubules was most evident in L. esculentum, while only about 50% of mitotic cells in the root meristems of P. sativum and V. faba displayed activated MAPKs localized to microtubules during mitosis. Unexpectedly, no evident immunofluorescence signals at spindle microtubules and phragmoplast were noted in L. luteus. Considering immunocytochemical analyses and studies on the impact of FR180204 (an inhibitor of animal ERK1/2) on mitotic cells, we hypothesize that MAPKs may not play prominent role in the regulation of microtubule dynamics in all plant species.

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

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

PubMed

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.

Soybean Homologs of MPK4 Negatively Regulate Defense Responses and Positively Regulate Growth and Development1[W][OA

PubMed Central

Liu, Jian-Zhong; Horstman, Heidi D.; Braun, Edward; Graham, Michelle A.; Zhang, Chunquan; Navarre, Duroy; Qiu, Wen-Li; Lee, Yeunsook; Nettleton, Dan; Hill, John H.; Whitham, Steven A.

2011-01-01

Mitogen-activated protein kinase (MAPK) cascades play important roles in disease resistance in model plant species such as Arabidopsis (Arabidopsis thaliana) and tobacco (Nicotiana tabacum). However, the importance of MAPK signaling pathways in the disease resistance of crops is still largely uninvestigated. To better understand the role of MAPK signaling pathways in disease resistance in soybean (Glycine max), 13, nine, and 10 genes encoding distinct MAPKs, MAPKKs, and MAPKKKs, respectively, were silenced using virus-induced gene silencing mediated by Bean pod mottle virus. Among the plants silenced for various MAPKs, MAPKKs, and MAPKKKs, those in which GmMAPK4 homologs (GmMPK4s) were silenced displayed strong phenotypes including stunted stature and spontaneous cell death on the leaves and stems, the characteristic hallmarks of activated defense responses. Microarray analysis showed that genes involved in defense responses, such as those in salicylic acid (SA) signaling pathways, were significantly up-regulated in GmMPK4-silenced plants, whereas genes involved in growth and development, such as those in auxin signaling pathways and in cell cycle and proliferation, were significantly down-regulated. As expected, SA and hydrogen peroxide accumulation was significantly increased in GmMPK4-silenced plants. Accordingly, GmMPK4-silenced plants were more resistant to downy mildew and Soybean mosaic virus compared with vector control plants. Using bimolecular fluorescence complementation analysis and in vitro kinase assays, we determined that GmMKK1 and GmMKK2 might function upstream of GmMPK4. Taken together, our results indicate that GmMPK4s negatively regulate SA accumulation and defense response but positively regulate plant growth and development, and their functions are conserved across plant species. PMID:21878550

Inflammatory signaling pathways induced by Helicobacter pylori in primary human gastric epithelial cells.

PubMed

Tran, Cong Tri; Garcia, Magali; Garnier, Martine; Burucoa, Christophe; Bodet, Charles

2017-02-01

Inflammatory signaling pathways induced by Helicobacter pylori remain unclear, having been studied mostly on cell-line models derived from gastric adenocarcinoma with potentially altered signaling pathways and nonfunctional receptors. Here, H. pylori-induced signaling pathways were investigated in primary human gastric epithelial cells. Inflammatory response was analyzed on chemokine mRNA expression and production after infection of gastric epithelial cells by H. pylori strains, B128 and B128Δ cagM, a cag type IV secretion system defective strain. Signaling pathway involvement was investigated using inhibitors of epidermal growth factor receptor (EGFR), MAPK, JAK and blocking Abs against TLR2 and TLR4. Inhibitors of EGFR, MAPK and JAK significantly reduced the chemokine mRNA expression and production induced by both H. pylori strains at 3 h and 24 h post-infection. JNK inhibitor reduced chemokine production at 24 h post-infection. Blocking Abs against TLR2 but not TLR4 showed significant reduction of chemokine secretion. Using primary culture of human gastric epithelial cells, our data suggest that H. pylori can be recognized by TLR2, leading to chemokine induction, and that EGFR, MAPK and the JAK/STAT signaling pathways play a key role in the H. pylori-induced CXCL1, CXCL5 and CXCL8 response in a cag pathogenicity island-independent manner.

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.

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

PubMed Central

Centuori, Sara M.; Martinez, Jesse D.

2014-01-01

A high fat diet coincides with elevated levels of bile acids. This elevation of 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. PMID:25027205

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

Inhibition of CD147 expression promotes chemosensitivity in HNSCC cells by deactivating MAPK/ERK signaling pathway.

PubMed

Ma, Chao; Wang, Jianqi; Fan, Longkun; Guo, Yanjun

2017-02-01

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers in the world. CD147, a transmembrane glycoprotein, has been reported to be correlated with cancer progression, metastasis, and chemoresistance in various cancers. In this study, we aimed to investigate the mechanism of CD147 in regulating drug resistance in HNSCC cells. qRT-PCR were used to evaluated the expression of CD147 in 57 HNSCC tumorous tissues and 2 cell lines. Increased expression of CD147 was found in most HNSCC samples, and the expression level of CD147 was correlated with multidrug resistance. CD147 RNA silencing decreased the chemoresistance of HNSCC cells by deactivating MAPK/ERK signaling pathway. Further investigation revealed that either rescue expression of CD147 or treatment of MAPK/ERK activator phorbol 12-myristate 13-acetate (PMA) in CD147 knockdown CRC cell line attenuated the decreased chemoresistance in CD147 knockdown cells. Taken together, our results suggest that CD147 promotes chemoresistance by activating MAPK/ERK signaling pathway in HNSCC. Copyright © 2017. Published by Elsevier Inc.

Mechanisms for type-II vitellogenesis-inhibiting hormone suppression of vitellogenin transcription in shrimp hepatopancreas: Crosstalk of GC/cGMP pathway with different MAPK-dependent cascades.

PubMed

Chen, Ting; Ren, Chunhua; Jiang, Xiao; Zhang, Lvping; Li, Hongmei; Huang, Wen; Hu, Chaoqun

2018-01-01

Vitellogenesis is the process of yolk formation via accumulating vitellin (Vn) with nutrients in the oocytes. Expression of vitellogenin (Vg), the precursor of Vn, is one of the indicators for the start of vitellogenesis. In Pacific white shrimp (Litopenaeus vannamei), the type-II vitellogenesis-inhibiting hormone (VIH-2) effectively suppresses hepatopancreatic Vg mRNA expression. In this study, we demonstrate the increasing transcript levels of hepatopancreatic Vg during L. vannamei ovarian development, suggesting that the hepatopancreas-derived Vg/Vn may also contribute to vitellogenesis in this species. Using a combination of in vivo injections and in vitro primary cell cultures, we provide evidences that the inhibition of VIH-2 on hepatopancreatic Vg gene expression is mediated through a functional coupling of the GC/cGMP pathway with different MAPK-dependent cascades in female shrimp. In VIH-2 signaling, the NO-independent GC/cGMP/PKG cascades were upstream of the MAPKs. Activations of the MAPK signal by VIH-2 include the phosphorylation of JNK and the mRNA/protein expression of P38MAPK. Additionally, the cAMP/PKA pathway is another positive intracellular signal for hepatopancreatic Vg mRNA expression but is independent of its VIH-2 regulation. Our findings establish a model for the signal transduction mechanism of Vg regulation by VIH and shed light on the biological functions and signaling of the CHH family in crustaceans.

Mechanisms for type-II vitellogenesis-inhibiting hormone suppression of vitellogenin transcription in shrimp hepatopancreas: Crosstalk of GC/cGMP pathway with different MAPK-dependent cascades

PubMed Central

Ren, Chunhua; Jiang, Xiao; Zhang, Lvping; Li, Hongmei; Huang, Wen; Hu, Chaoqun

2018-01-01

Vitellogenesis is the process of yolk formation via accumulating vitellin (Vn) with nutrients in the oocytes. Expression of vitellogenin (Vg), the precursor of Vn, is one of the indicators for the start of vitellogenesis. In Pacific white shrimp (Litopenaeus vannamei), the type-II vitellogenesis-inhibiting hormone (VIH-2) effectively suppresses hepatopancreatic Vg mRNA expression. In this study, we demonstrate the increasing transcript levels of hepatopancreatic Vg during L. vannamei ovarian development, suggesting that the hepatopancreas-derived Vg/Vn may also contribute to vitellogenesis in this species. Using a combination of in vivo injections and in vitro primary cell cultures, we provide evidences that the inhibition of VIH-2 on hepatopancreatic Vg gene expression is mediated through a functional coupling of the GC/cGMP pathway with different MAPK-dependent cascades in female shrimp. In VIH-2 signaling, the NO-independent GC/cGMP/PKG cascades were upstream of the MAPKs. Activations of the MAPK signal by VIH-2 include the phosphorylation of JNK and the mRNA/protein expression of P38MAPK. Additionally, the cAMP/PKA pathway is another positive intracellular signal for hepatopancreatic Vg mRNA expression but is independent of its VIH-2 regulation. Our findings establish a model for the signal transduction mechanism of Vg regulation by VIH and shed light on the biological functions and signaling of the CHH family in crustaceans. PMID:29590153

The Antiviral Alkaloid Berberine Reduces Chikungunya Virus-Induced Mitogen-Activated Protein Kinase Signaling

PubMed Central

Thaa, Bastian; Amrun, Siti Naqiah; Simarmata, Diane; Rausalu, Kai; Nyman, Tuula A.; Merits, Andres; McInerney, Gerald M.; Ng, Lisa F. P.

2016-01-01

ABSTRACT Chikungunya virus (CHIKV) has infected millions of people in the tropical and subtropical regions since its reemergence in the last decade. We recently identified the nontoxic plant alkaloid berberine as an antiviral substance against CHIKV in a high-throughput screen. Here, we show that berberine is effective in multiple cell types against a variety of CHIKV strains, also at a high multiplicity of infection, consolidating the potential of berberine as an antiviral drug. We excluded any effect of this compound on virus entry or on the activity of the viral replicase. A human phosphokinase array revealed that CHIKV infection specifically activated the major mitogen-activated protein kinase (MAPK) signaling pathways extracellular signal-related kinase (ERK), p38 and c-Jun NH2-terminal kinase (JNK). Upon treatment with berberine, this virus-induced MAPK activation was markedly reduced. Subsequent analyses with specific inhibitors of these kinases indicated that the ERK and JNK signaling cascades are important for the generation of progeny virions. In contrast to specific MAPK inhibitors, berberine lowered virus-induced activation of all major MAPK pathways and resulted in a stronger reduction in viral titers. Further, we assessed the in vivo efficacy of berberine in a mouse model and measured a significant reduction of CHIKV-induced inflammatory disease. In summary, we demonstrate the efficacy of berberine as a drug against CHIKV and highlight the importance of the MAPK signaling pathways in the alphavirus infectious cycle. IMPORTANCE Chikungunya virus (CHIKV) is a mosquito-borne virus that causes severe and persistent muscle and joint pain and has recently spread to the Americas. No licensed drug exists to counter this virus. In this study, we report that the alkaloid berberine is antiviral against different CHIKV strains and in multiple human cell lines. We demonstrate that berberine collectively reduced the virus-induced activation of cellular mitogen-activated protein kinase signaling. The relevance of these signaling cascades in the viral life cycle was emphasized by specific inhibitors of these kinase pathways, which decreased the production of progeny virions. Berberine significantly reduced CHIKV-induced inflammatory disease in a mouse model, demonstrating efficacy of the drug in vivo. Overall, this work makes a strong case for pursuing berberine as a potential anti-CHIKV therapeutic compound and for exploring the MAPK signaling pathways as antiviral targets against alphavirus infections. PMID:27535052

Gelidium elegans Extract Ameliorates Type 2 Diabetes via Regulation of MAPK and PI3K/Akt Signaling.

PubMed

Choi, Jia; Kim, Kui-Jin; Koh, Eun-Jeong; Lee, Boo-Yong

2018-01-06

Gelidium elegans , a red alga native to the Asia Pacific region, contains biologically active polyphenols. We conducted a molecular biological study of the anti-diabetic effect of Gelidium elegans extract (GEE) in C57BL/KsJ-db/db mice. Mice that had been administered GEE had significantly lower body mass, water consumption, and fasting blood glucose than db/db controls. Moreover, hemoglobin A1c (HbA1c), an indicator of the glycemic status of people with diabetes, was significantly lower in mice that had been administered GEE. We also found that 200 mg/kg/day GEE upregulates the insulin signaling pathway by activating insulin receptor substrate-1 (IRS-1) and phosphoinositide 3-kinase (PI3K), and increasing the expression of glucose transporter type 4 (GLUT4). In parallel, mitogen-activated protein kinase (MAPK) activity was lower in GEE-treated groups. In summary, these findings indicate that GEE regulates glucose metabolism by activating the insulin signaling pathway and downregulating the MAPK signaling pathway.

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.

Development of a High-Throughput Gene Expression Screen for Modulators of RAS-MAPK Signaling in a Mutant RAS Cellular Context.

PubMed

Severyn, Bryan; Nguyen, Thi; Altman, Michael D; Li, Lixia; Nagashima, Kumiko; Naumov, George N; Sathyanarayanan, Sriram; Cook, Erica; Morris, Erick; Ferrer, Marc; Arthur, Bill; Benita, Yair; Watters, Jim; Loboda, Andrey; Hermes, Jeff; Gilliland, D Gary; Cleary, Michelle A; Carroll, Pamela M; Strack, Peter; Tudor, Matt; Andersen, Jannik N

2016-10-01

The RAS-MAPK pathway controls many cellular programs, including cell proliferation, differentiation, and apoptosis. In colorectal cancers, recurrent mutations in this pathway often lead to increased cell signaling that may contribute to the development of neoplasms, thereby making this pathway attractive for therapeutic intervention. To this end, we developed a 26-member gene signature of RAS-MAPK pathway activity utilizing the Affymetrix QuantiGene Plex 2.0 reagent system and performed both primary and confirmatory gene expression-based high-throughput screens (GE-HTSs) using KRAS mutant colon cancer cells (SW837) and leveraging a highly annotated chemical library. The screen achieved a hit rate of 1.4% and was able to enrich for hit compounds that target RAS-MAPK pathway members such as MEK and EGFR. Sensitivity and selectivity performance measurements were 0.84 and 1.00, respectively, indicating high true-positive and true-negative rates. Active compounds from the primary screen were confirmed in a dose-response GE-HTS assay, a GE-HTS assay using 14 additional cancer cell lines, and an in vitro colony formation assay. Altogether, our data suggest that this GE-HTS assay will be useful for larger unbiased chemical screens to identify novel compounds and mechanisms that may modulate the RAS-MAPK pathway. © 2016 Society for Laboratory Automation and Screening.

Alterations in BRAF gene, and enhanced mTOR and MAPK signaling in dysembryoplastic neuroepithelial tumors (DNTs).

PubMed

Kakkar, Aanchal; Majumdar, Atreye; Kumar, Anupam; Tripathi, Manjari; Pathak, Pankaj; Sharma, Mehar C; Suri, Vaishali; Tandon, Vivek; Chandra, Sarat P; Sarkar, Chitra

2016-11-01

Recently, BRAF V600E mutation, and activation of mTOR and MAPK pathways have been identified in various glial/glioneuronal tumors. Dysembryoplastic neuroepithelial tumors (DNTs) are epilepsy-associated glioneuronal neoplasms which have not been analyzed extensively in this respect. Sequencing for BRAF V600E mutation, analysis of BRAF copy number by qRT-PCR, and immunohistochemistry for mTOR (p-S6, p-4EBP1) and MAPK (p-MAPK) pathways were performed. Sixty-four DNTs were identified, accounting for 15.1% of patients with drug-refractory epilepsy (mean age: 15.5 years). Duration of seizures ranged from 1 to 22 years. BRAF V600E mutation was identified in 3.7% of DNTs, while BRAF copy number gain was observed in 33.3%. mTOR-pathway activation indicated by p-S6 or p-4EBP1 immunopositivity was seen in 89.7% cases. Interestingly, p-S6 positivity was also seen in adjacent dysplastic cortex. p-MAPK immunopositivity was seen in 50% cases. MAPK and mTOR pathway activation was independent of BRAF alterations. All patients that underwent incomplete resection had Engel grade II-III outcomes (p<0.001). BRAF alterations are frequent in DNTs, particularly BRAF copy number gain which is being reported for the first time in these tumors. Evidence of activation of mTOR and MAPK pathways suggests a role for altered signalling in DNT pathogenesis, and will pave the way for development of targeted therapies, particularly relevant for patients having persistent seizures after incomplete resection. Copyright © 2016 Elsevier B.V. All rights reserved.

Amphiregulin and PTEN evoke a multimodal mechanism of acquired resistance to PI3K inhibition

PubMed Central

Edgar, Kyle A.; Crocker, Lisa; Cheng, Eric; Wagle, Marie-Claire; Wongchenko, Matthew; Yan, Yibing; Wilson, Timothy R.; Dompe, Nicholas; Neve, Richard M.; Belvin, Marcia; Sampath, Deepak; Friedman, Lori S.; Wallin, Jeffrey J.

2014-01-01

Phosphoinositide-3 kinase (PI3K) signaling pathway alterations occur broadly in cancer and PI3K is a promising therapeutic target. Here, we investigated acquired resistance to GDC-0941, a PI3K inhibitor in clinical trials. Colorectal cancer (CRC) cells made to be resistant to GDC-0941 were discovered to secrete amphiregulin, which resulted in increased EGFR/MAPK signaling. Moreover, prolonged PI3K pathway inhibition in cultured cells over a period of months led to a secondary loss of PTEN in 40% of the CRC lines with acquired resistance to PI3K inhibition. In the absence of PI3K inhibitor, these PTEN-null PI3K inhibitor-resistant clones had elevated PI3K pathway signaling and decreased sensitivity to MAPK pathway inhibitors. Importantly, PTEN loss was not able to induce resistance to PI3K inhibitors in the absence of amphiregulin, indicating a multimodal mechanism of acquired resistance. The combination of PI3K and MAPK pathway inhibitors overcame acquired resistance in vitro and in vivo. PMID:25053989

Amphiregulin and PTEN evoke a multimodal mechanism of acquired resistance to PI3K inhibition.

PubMed

Edgar, Kyle A; Crocker, Lisa; Cheng, Eric; Wagle, Marie-Claire; Wongchenko, Matthew; Yan, Yibing; Wilson, Timothy R; Dompe, Nicholas; Neve, Richard M; Belvin, Marcia; Sampath, Deepak; Friedman, Lori S; Wallin, Jeffrey J

2014-03-01

Phosphoinositide-3 kinase (PI3K) signaling pathway alterations occur broadly in cancer and PI3K is a promising therapeutic target. Here, we investigated acquired resistance to GDC-0941, a PI3K inhibitor in clinical trials. Colorectal cancer (CRC) cells made to be resistant to GDC-0941 were discovered to secrete amphiregulin, which resulted in increased EGFR/MAPK signaling. Moreover, prolonged PI3K pathway inhibition in cultured cells over a period of months led to a secondary loss of PTEN in 40% of the CRC lines with acquired resistance to PI3K inhibition. In the absence of PI3K inhibitor, these PTEN-null PI3K inhibitor-resistant clones had elevated PI3K pathway signaling and decreased sensitivity to MAPK pathway inhibitors. Importantly, PTEN loss was not able to induce resistance to PI3K inhibitors in the absence of amphiregulin, indicating a multimodal mechanism of acquired resistance. The combination of PI3K and MAPK pathway inhibitors overcame acquired resistance in vitro and in vivo.

BMP15 regulates AMH expression via the p38 MAPK pathway in granulosa cells from goat.

PubMed

Zhao, Zhongquan; Guo, Fangyue; Sun, Xiaowei; He, Qijie; Dai, Zinuo; Chen, Xiaochuan; Zhao, Yongju; Wang, Jian

2018-05-31

Anti-Mullerian hormone (AMH), a member of the TGF-β superfamily, is produced by granulosa cells (GCs) of preantral and small antral follicles and plays a role in regulating the recruitment of primordial follicles and the FSH-dependent development of follicles. However, the regulation of AMH expression in follicles remains poorly understood. The objectives of this study were to determine the following: 1. the association between bone morphogenetic protein 15 (BMP15) and AMH; 2. whether BMP15 can regulate the expression of AMH by inhibiting the p38 MAPK pathway; and 3. whether SRY-related HMG box 9 (SOX9), a transcription factor for AMH, is involved in the regulation of AMH expression by BMP15. In this study, an inhibitor of p38 MAPK and an siRNA specific for p38 MAPK were used to prevent the function of the p38 MAPK signaling pathway. Then, AMH mRNA expression and AMH secretion were detected in goat GCs using an RT-PCR assay and ELISA, respectively, after treatment with BMP15. The results indicated that BMP15 up-regulates the transcription of AMH and that the inhibition of p38 MAPK decreases the BMP15-induced expression of AMH and SOX9, suggesting that BMP15 up-regulates the expression of AMH via the p38 MAPK signaling pathway, and this process involves the SOX9 transcription factor. Copyright © 2018 Elsevier Inc. All rights reserved.

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

PubMed

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

2015-05-01

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.

Species Comparison of the Role of p38 MAP Kinase in the Female Reproductive System.

PubMed

Radi, Zaher A; Marusak, Rosemary A; Morris, Dale L

2009-06-01

The p38 mitogen-activated protein kinases (MAPKs) are members of discrete signal transduction pathways that have significant regulatory roles in a variety of biological processes, depending on the cell, tissue and organ type. p38 MAPKs are involved in inflammation, cell growth and differentiation and cell cycle. In the female reproductive system, p38 MAPKs are known to regulate various aspects of the reproductive process such as mammalian estrous and menstrual cycles as well as early pregnancy and parturition. p38 MAPKs have also been implicated in alterations and pathologies observed in the female reproductive system. Therefore, pharmacologic modulation of p38 MAPKs, and inter-connected signaling pathways (e.g., estrogen receptor signaling, c-fos, c-jun), may influence reproductive physiology and function. This article provides a critical, comparative review of available data on the roles of p38 MAPKs in the mammalian female reproductive system and in reproductive pathophysiology in humans and preclinical species. We first introduce fundamental differences and similarities of the mammalian female reproductive system that should be considered by toxicologists and toxicologic pathologists when assessing the effects of new pharmacologic agents on the female reproductive system. We then explore in detail the known roles for p38 MAPKs and related molecules in female reproduction. This foundation is then extended to pathological conditions in which p38 MAPKs are thought to play an integral role.

Serotonin disrupts esophageal mucosal integrity: an investigation using a stratified squamous epithelial model.

PubMed

Wu, Liping; Oshima, Tadayuki; Tomita, Toshihiko; Ohda, Yoshio; Fukui, Hirokazu; Watari, Jiro; Miwa, Hiroto

2016-11-01

Serotonin regulates gastrointestinal function, and mast cells are a potential nonneuronal source of serotonin in the esophagus. Tight junction (TJ) proteins in the esophageal epithelium contribute to the barrier function, and the serotonin signaling pathway may contribute to epithelial leakage in gastroesophageal reflux disease. Therefore, the aim of this study was to investigate the role of serotonin on barrier function, TJ proteins, and related signaling pathways. Normal primary human esophageal epithelial cells were cultured with use of an air-liquid interface system. Serotonin was added to the basolateral compartment, and transepithelial electrical resistance (TEER) was measured. The expression of TJ proteins and serotonin receptor 7 (5-HT 7 ) was assessed by Western blotting. The involvement of 5-HT 7 was assessed with use of an antagonist and an agonist. The underlying cellular signaling pathways were examined with use of specific blockers. Serotonin decreased TEER and reduced the expression of TJ proteins ZO-1, occludin, and claudin 1, but not claudin 4. A 5-HT 7 antagonist blocked the serotonin-induced decrease in TEER, and a 5-HT 7 agonist decreased TEER. Inhibition of p38 mitogen-activated protein kinase (MAPK) reduced the serotonin-induced decrease in TEER. Inhibition of p38 MAPK blocked the decrease of ZO-1 levels, whereas extracellular-signal-regulated kinase (ERK) inhibition blocked the decrease in occludin levels. Cell signaling pathway inhibitors had no effect on serotonin-induced alterations in claudin 1 and claudin 4 levels. Serotonin induced phosphorylation of p38 MAPK and ERK, and a 5-HT 7 antagonist partially blocked serotonin-induced phosphorylation of p38 MAPK but not that of ERK. Serotonin disrupted esophageal squamous epithelial barrier function by modulating the levels of TJ proteins. Serotonin signaling pathways may mediate the pathogenesis of gastroesophageal reflux disease.

Aldosterone Induces Apoptosis in Rat Podocytes: Role of PI3-K/Akt and p38MAPK Signaling Pathways

PubMed Central

Chen, Cheng; Liang, Wei; Jia, Junya; van Goor, Harry; Singhal, Pravin C.; Ding, Guohua

2009-01-01

Background Podocytes play a critical role in the pathogenesis of glomerulosclerosis. Increasing evidence suggests that aldosterone (ALD) is involved in the initiation and progression of glomerular damage. It is, however, unknown whether there is a direct injurious effect of ALD on podocytes. Therefore, in the present study, we evaluated the effect of ALD on podocyte apoptosis and studied the role of phosphatidylinositol 3-kinase/Akt (PI3-K/Akt) and p38 mitogen-activated protein kinase (p38MAPK) signaling pathways in this process. Methods Podocytes were incubated in media containing either buffer or increasing concentrations of ALD (10–9∼10–5M) for variable time periods. The cells were also treated with either wortmannin (inhibitor of PI3-K, 100 nM), SB202190 (SB20, inhibitor of p38MAPK, 10 μM) or buffer. All treatments were performed with or without ALD (10–7M) for 24 h. At the end of the incubation period, apoptosis was evaluated by cell nucleus staining and flow cytometric analyses. Activation of PI3-K/Akt and p38MAPK phosphorylation of cultured rat podocytes was evaluated by performing Akt kinase assay and Western blot, respectively. Results Apoptosis of cultured rat podocytes was induced by ALD in a dose- and time-dependent manner. ALD inhibited the activity of PI3-K/Akt and increased the activation of p38MAPK. PI3-K/Akt activity was further inhibited by the addition of wortmannin to the cells in the presence of ALD. This was accompanied by a significant increase in apoptosis. ALD-induced p38MAPK phosphorylation and apoptosis were inhibited when the cells were pretreated with SB20. Furthermore, treatment with spironolactone not only attenuated the proapoptotic effect of ALD, but also significantly reversed its effects on PI3-K/Akt and p38MAPK signaling pathways. Conclusion ALD induces apoptosis in rat podocytes through inhibition of PI3-K/Akt and stimulation of p38 MAPK signaling pathways. Spironolactone attenuates ALD-induced podocyte apoptosis, thereby positioning this compound as a potential promising target of intervention in human renal damage. PMID:19590239

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.

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

PubMed Central

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

2010-01-01

Human natural killer (NK) cells are lymphocytes that destroy tumor and virally infected cells. Previous studies have shown that exposures of NK cells to tributyltin (TBT) greatly diminish their ability to destroy tumor cells (lytic function) while activating mitogen-activated protein kinases (MAPK) (p44/42, p38, and JNK) in the NK cells. The signaling pathway that regulates NK lytic function appears to include activation of protein kinase C (PKC) as well as MAPK activity. The 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 the inhibition of NK lysis of tumor cells and activation of MAPKs caused by TBT exposures. TBT caused a 2–3 fold activation of PKC at concentrations ranging from 50–300 nM (16–98 ng/mL), indicating that activation of PKC occurs in response to TBT exposures. 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 the activation of p44/42 by TBT in NK cells. PMID:20390410

Electromagnetic-pulse-induced activation of p38 MAPK pathway and disruption of blood-retinal barrier.

PubMed

Li, Hai-Juan; Guo, Liang-Mei; Yang, Long-Long; Zhou, Yong-Chun; Zhang, Yan-Jun; Guo, Juan; Xie, Xue-Jun; Guo, Guo-Zhen

2013-06-20

The blood-retinal barrier (BRB) is critical for maintaining retina homeostasis and low permeability. In this study, we evaluated the effects of electromagnetic pulse (EMP) exposure on the permeability of BRB, alterations of tight junction (TJ) proteins of BRB and if any, involvement of mitogen-activated protein kinase (MAPK) pathway. Male Sprague-Dawley (SD) rats and RF/6A cells which were pretreated with or without MAPKs inhibitors were sham exposed or exposed to EMP at 200kV/m for 200 pulses. The alteration of BRB permeability was examined through fluorescence microscope and quantitatively assessed using Evans blue (EB) and endogenous albumin as tracers. The expressions of TJ proteins and some signaling molecules of MAPK pathway were measured by Western blots. The observations were that EMP exposure resulted in increased BRB permeability concurrent with the decreased expressions of occludin and claudin-5, which were correlated with the increased expressions of phospho-p38, phospho-JNK and phospho-ERK and could be blocked when pretreated with p38 MAPK inhibitor. Thus, the results suggested that the alterations of occludin and claudin-5 may play an important role in the disruption of TJs, which may lead to the transient breakdown of BRB after EMP exposure with the involvement of p38 MAPK pathway through phosphorylation of signaling molecules. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Zinc transporter ZnT-3 regulates presynaptic Erk1/2 signaling and hippocampus-dependent memory.

PubMed

Sindreu, Carlos; Palmiter, Richard D; Storm, Daniel R

2011-02-22

The physiological role of vesicular zinc at central glutamatergic synapses remains poorly understood. Here we show that mice lacking the synapse-specific vesicular zinc transporter ZnT3 (ZnT3KO mice) have reduced activation of the Erk1/2 MAPK in hippocampal mossy fiber terminals, disinhibition of zinc-sensitive MAPK tyrosine phosphatase activity, and impaired MAPK signaling during hippocampus-dependent learning. Activity-dependent exocytosis is required for the effect of zinc on presynaptic MAPK and phosphatase activity. ZnT3KO mice have complete deficits in contextual discrimination and spatial working memory. Local blockade of zinc or MAPK in the mossy fiber pathway of wild-type mice impairs contextual discrimination. We conclude that ZnT3 is important for zinc homeostasis modulating presynaptic MAPK signaling and is required for hippocampus-dependent memory.

Zinc transporter ZnT-3 regulates presynaptic Erk1/2 signaling and hippocampus-dependent memory

PubMed Central

Sindreu, Carlos; Palmiter, Richard D.; Storm, Daniel R.

2011-01-01

The physiological role of vesicular zinc at central glutamatergic synapses remains poorly understood. Here we show that mice lacking the synapse-specific vesicular zinc transporter ZnT3 (ZnT3KO mice) have reduced activation of the Erk1/2 MAPK in hippocampal mossy fiber terminals, disinhibition of zinc-sensitive MAPK tyrosine phosphatase activity, and impaired MAPK signaling during hippocampus-dependent learning. Activity-dependent exocytosis is required for the effect of zinc on presynaptic MAPK and phosphatase activity. ZnT3KO mice have complete deficits in contextual discrimination and spatial working memory. Local blockade of zinc or MAPK in the mossy fiber pathway of wild-type mice impairs contextual discrimination. We conclude that ZnT3 is important for zinc homeostasis modulating presynaptic MAPK signaling and is required for hippocampus-dependent memory. PMID:21245308

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

PubMed Central

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

2009-01-01

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

Subverting Toll-Like Receptor Signaling by Bacterial Pathogens

PubMed Central

McGuire, Victoria A.; Arthur, J. Simon C.

2015-01-01

Pathogenic bacteria are detected by pattern-recognition receptors (PRRs) expressed on innate immune cells, which activate intracellular signal transduction pathways to elicit an immune response. Toll-like receptors are, perhaps, the most studied of the PRRs and can activate the mitogen-activated protein kinase (MAPK) and Nuclear Factor-κB (NF-κB) pathways. These pathways are critical for mounting an effective immune response. In order to evade detection and promote virulence, many pathogens subvert the host immune response by targeting components of these signal transduction pathways. This mini-review highlights the diverse mechanisms that bacterial pathogens have evolved to manipulate the innate immune response, with a particular focus on those that target MAPK and NF-κB signaling pathways. Understanding the elaborate strategies that pathogens employ to subvert the immune response not only highlights the importance of these proteins in mounting effective immune responses, but may also identify novel approaches for treatment or prevention of infection. PMID:26648936

Angiotensin II increases CTGF expression via MAPKs/TGF-{beta}1/TRAF6 pathway in atrial fibroblasts

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

Gu, Jun; Liu, Xu, E-mail: xkliuxu@yahoo.cn; Wang, Quan-xing, E-mail: shmywqx@126.com

2012-10-01

The activation of transforming growth factor-{beta}1(TGF-{beta}1)/Smad signaling pathway and increased expression of connective tissue growth factor (CTGF) induced by angiotensin II (AngII) have been proposed as a mechanism for atrial fibrosis. However, whether TGF{beta}1/non-Smad signaling pathways involved in AngII-induced fibrogenetic factor expression remained unknown. Recently tumor necrosis factor receptor associated factor 6 (TRAF6)/TGF{beta}-associated kinase 1 (TAK1) has been shown to be crucial for the activation of TGF-{beta}1/non-Smad signaling pathways. In the present study, we explored the role of TGF-{beta}1/TRAF6 pathway in AngII-induced CTGF expression in cultured adult atrial fibroblasts. AngII (1 {mu}M) provoked the activation of P38 mitogen activated proteinmore » kinase (P38 MAPK), extracellular signal-regulated kinase 1/2(ERK1/2) and c-Jun NH(2)-terminal kinase (JNK). AngII (1 {mu}M) also promoted TGF{beta}1, TRAF6, CTGF expression and TAK1 phosphorylation, which were suppressed by angiotensin type I receptor antagonist (Losartan) as well as p38 MAPK inhibitor (SB202190), ERK1/2 inhibitor (PD98059) and JNK inhibitor (SP600125). Meanwhile, both TGF{beta}1 antibody and TRAF6 siRNA decreased the stimulatory effect of AngII on TRAF6, CTGF expression and TAK1 phosphorylation, which also attenuated AngII-induced atrial fibroblasts proliferation. In summary, the MAPKs/TGF{beta}1/TRAF6 pathway is an important signaling pathway in AngII-induced CTGF expression, and inhibition of TRAF6 may therefore represent a new target for reversing Ang II-induced atrial fibrosis. -- Highlights: Black-Right-Pointing-Pointer MAPKs/TGF{beta}1/TRAF6 participates in AngII-induced CTGF expression in atrial fibroblasts. Black-Right-Pointing-Pointer TGF{beta}1/TRAF6 participates in AngII-induced atrial fibroblasts proliferation. Black-Right-Pointing-Pointer TRAF6 may represent a new target for reversing Ang II-induced atrial fibrosis.« less

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

PubMed

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

2015-07-01

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

The stimulus-dependent co-localization of serum- and glucocorticoid-regulated protein kinase (Sgk) and Erk/MAPK in mammary tumor cells involves the mutual interaction with the importin-alpha nuclear import protein

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

Buse, Patricia; Maiyar, Anita C.; Failor, Kim L.

2007-09-10

In Con8 rat mammary epithelial tumor cells, indirect immunofluorescence revealed that Sgk (serum- and glucocorticoid-regulated kinase) and Erk/MAPK (extracellular signal-regulated protein kinase/mitogen activated protein kinase) co-localized to the nucleus in serum-treated cells and to the cytoplasmic compartment in cells treated with the synthetic glucocorticoid dexamethasone. Moreover, the subcellular distribution of the importin-alpha nuclear transport protein was similarly regulated in a signal-dependent manner. In vitro GST-pull down assays revealed the direct interaction of importin-alpha with either Sgk or Erk/MAPK, while RNA interference knockdown of importin-alpha expression disrupted the localization of both Sgk and Erk into the nucleus of serum-treated cells. Wildmore » type or kinase dead forms of Sgk co-immunoprecipitated with Erk/MAPK from either serum- or dexamethasone-treated mammary tumor cells, suggesting the existence of a protein complex containing both kinases. In serum-treated cells, nucleus residing Sgk and Erk/MAPK were both hyperphosphorylated, indicative of their active states, whereas, in dexamethasone-treated cells Erk/MAPK, but not Sgk, was in its inactive hypophosphorylated state. Treatment with a MEK inhibitor, which inactivates Erk/MAPK, caused the relocalization of both Sgk and ERK to the cytoplasm. We therefore propose that the signal-dependent co-localization of Sgk and Erk/MAPK mediated by importin-alpha represents a new pathway of signal integration between steroid and serum/growth factor-regulated pathways.« less

MAP Kinase-Mediated Negative Regulation of Symbiotic Nodule Formation in Medicago truncatula.

PubMed

Ryu, Hojin; Laffont, Carole; Frugier, Florian; Hwang, Ildoo

2017-01-01

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events in plants, including stress responses, innate immunity, hormone signaling, and cell specificity. MAPK-mediated stress signaling is also known to negatively regulate nitrogen-fixing symbiotic interactions, but the molecular mechanism of the MAPK signaling cascades underlying the symbiotic nodule development remains largely unknown. We show that the MtMKK5-MtMPK3/6 signaling module negatively regulates the early symbiotic nodule formation, probably upstream of ERN1 (ERF Required for Nodulation 1) and NSP1 (Nod factor Signaling Pathway 1) in Medicago truncatula . The overexpression of MtMKK5 stimulated stress and defense signaling pathways but also reduced nodule formation in M. truncatula roots. Conversely, a MAPK specific inhibitor, U0126, enhanced nodule formation and the expression of an early nodulation marker gene, MtNIN . We found that MtMKK5 directly activates MtMPK3/6 by phosphorylating the TEY motif within the activation loop and that the MtMPK3/6 proteins physically interact with the early nodulation-related transcription factors ERN1 and NSP1. These data suggest that the stress signaling-mediated MtMKK5/MtMPK3/6 module suppresses symbiotic nodule development via the action of early nodulation transcription factors.

MAP Kinase-Mediated Negative Regulation of Symbiotic Nodule Formation in Medicago truncatula

PubMed Central

Ryu, Hojin; Laffont, Carole; Frugier, Florian; Hwang, Ildoo

2017-01-01

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events in plants, including stress responses, innate immunity, hormone signaling, and cell specificity. MAPK-mediated stress signaling is also known to negatively regulate nitrogen-fixing symbiotic interactions, but the molecular mechanism of the MAPK signaling cascades underlying the symbiotic nodule development remains largely unknown. We show that the MtMKK5-MtMPK3/6 signaling module negatively regulates the early symbiotic nodule formation, probably upstream of ERN1 (ERF Required for Nodulation 1) and NSP1 (Nod factor Signaling Pathway 1) in Medicago truncatula. The overexpression of MtMKK5 stimulated stress and defense signaling pathways but also reduced nodule formation in M. truncatula roots. Conversely, a MAPK specific inhibitor, U0126, enhanced nodule formation and the expression of an early nodulation marker gene, MtNIN. We found that MtMKK5 directly activates MtMPK3/6 by phosphorylating the TEY motif within the activation loop and that the MtMPK3/6 proteins physically interact with the early nodulation-related transcription factors ERN1 and NSP1. These data suggest that the stress signaling-mediated MtMKK5/MtMPK3/6 module suppresses symbiotic nodule development via the action of early nodulation transcription factors. PMID:28152300

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

PubMed

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

2017-04-03

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

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

PubMed

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

2010-12-01

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

Betalactam antibiotics affect human dendritic cells maturation through MAPK/NF-kB systems. Role in allergic reactions to drugs

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

Lopez, Soledad; Department of Medical Biochemistry, Molecular Biology and Immunology, The University of Seville Medical School, Seville; Gomez, Enrique

The mechanisms leading to drug allergy in predisposed patients, especially those related to T-cell-mediated drug hypersensitivity, are not well understood. A key event in allergic reactions to drugs is the maturation process undergone by dendritic cells (DCs). Although amoxicillin (AX) has been reported to interact and maturate DCs from patients with AX-induced delayed-type hypersensitivity, the cell signaling pathways related to AX-mediated DC maturation have not been elucidated. We sought to determine the role of the MAPK and NF-κΒ pathways on AX-induced DC maturation and functional status. For that purpose, in monocyte-derived-DCs from AX-delayed allergic patients and tolerant subjects, we analyzedmore » the activation pattern of p38MAPK, JNK, and ERK signaling and the NF-κB, maturation markers as well as endocytosis and allostimulatory capacities driven by AX-stimulated-DCs. Our data reveal that AX induces an increase in the phosphorylation levels of the three MAPKsand activated NF-κB in DCs from allergic patients. Moreover, the inhibition of these pathways prevents the up-regulation of surface molecules induced by AX. Additionally, we observed that the allostimulatory capacity and the endocytosis down-regulation in AX-stimulated-DCs from allergic patients depend on JNK and NF-κB activities. Taken together, our data shed light for the first time on the main signaling pathways involved in DC maturation from AX-delayed allergic patient. - Highlights: • The cell signaling pathways related to drug-mediated DC maturation were tested. • Amoxicillin induces activation of MAPK and NF-κB in DCs from allergic patients. • The inhibition of these pathways prevents the up-regulation of DC surface molecules. • Their allostimulatory and endocytosis capacities depend on JNK and NF-κB activities. • The low involvement of p38-MAPK could be the cause of an incomplete DC maturation.« less

Antagonizing retinoic acid and FGF/MAPK pathways control posterior body patterning in the invertebrate chordate Ciona intestinalis.

PubMed

Pasini, Andrea; Manenti, Raoul; Rothbächer, Ute; Lemaire, Patrick

2012-01-01

Vertebrate embryos exploit the mutual inhibition between the RA and FGF signalling pathways to coordinate the proliferative elongation of the main body axis with the progressive patterning and differentiation of its neuroectodermal and paraxial mesodermal structures. The evolutionary history of this patterning system is still poorly understood. Here, we investigate the role played by the RA and FGF/MAPK signals during the development of the tail structures in the tunicate Ciona intestinalis, an invertebrate chordate belonging to the sister clade of vertebrates, in which the prototypical chordate body plan is established through very derived morphogenetic processes. Ciona embryos are constituted of few cells and develop according to a fixed lineage; elongation of the tail occurs largely by rearrangement of postmitotic cells; mesoderm segmentation and somitogenesis are absent. We show that in the Ciona embryo, the antagonism of the RA and FGF/MAPK signals is required to control the anteroposterior patterning of the tail epidermis. We also demonstrate that the RA, FGF/MAPK and canonical Wnt pathways control the anteroposterior patterning of the tail peripheral nervous system, and reveal the existence of distinct subpopulations of caudal epidermal neurons with different responsiveness to the RA, FGF/MAPK and canonical Wnt signals. Our data provide the first demonstration that the use of the antagonism between the RA and FGF signals to pattern the main body axis predates the emergence of vertebrates and highlight the evolutionary plasticity of this patterning strategy, showing that in different chordates it can be used to pattern different tissues within the same homologous body region.

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Various stressors rapidly activate the p38-MAPK signaling pathway in Mytilus galloprovincialis (Lam.).

PubMed

Gaitanaki, Catherine; Kefaloyianni, Erene; Marmari, Athina; Beis, Isidoros

2004-05-01

The stimulation of p38-MAPK signal transduction pathway by various stressful stimuli was investigated in the marine bivalve M. galloprovincialis. Oxidative stress (5 microM H2O2) induced a biphasic pattern of p38-MAPK phosphorylation with maximal values attained at 15 min (8.1-fold) and 1 h (8.0-fold) of treatment respectively. Furthermore, 1 microM SB203580 abolished the p38-MAPK phosphorylation induced by oxidative stress. Aerial exposure also induced a biphasic pattern of p38-MAPK phosphorylation, with maximal values attained at 1 h (6.8-fold) and 8 h (4.9-fold) respectively. Re-oxygenation following a 15 min of aerial exposure resulted in the progressive dephosphorylation of the kinase. Treatment with 0.5 M sorbitol (in normal seawater) induced the rapid kinase phosphorylation (9.2-fold) and this effect was reversible. Seawater salinities varying between 100-60% had no effect, whereas a salinity of 50% induced a significant p38-MAPK phosphorylation. Furthermore, hypertonicity (120% seawater) resulted in a moderate kinase phosphorylation. All the above results demonstrate for the first time in a marine invertebrate imposed to environmental and other forms of stress as an intact, living organism, that the p38-MAPK pathway is specifically activated by various stressful stimuli which this animal can often face and sustain in vivo.

Interleukin 6 inhibits proliferation and, in cooperation with an epidermal growth factor receptor autocrine loop, increases migration of T47D breast cancer cells.

PubMed

Badache, A; Hynes, N E

2001-01-01

Interleukin (IL)-6, a multifunctional regulator of immune response, hematopoiesis, and acute phase reactions, has also been shown to regulate cancer cell proliferation. We have investigated IL-6 signaling pathways and cellular responses in the T47D breast carcinoma cell line. The IL-6-type cytokines, IL-6 and oncostatin M, simultaneously inhibited cell proliferation and increased cell migration. In T47D cells, IL-6 stimulated the activation of Janus-activated kinase 1 tyrosine kinase and signal transducers and activators of transcription (STAT) 1 and STAT3 transcription factors. Expression of dominant negative STAT3 in the cells strongly reduced IL-6-mediated growth inhibition but did not prevent IL-6-induced cell migration. IL-6 treatment led to activation of the mitogen-activated protein kinase (MAPK) and the phosphatidylinositol 3'-kinase (PI3K) pathways. Inhibition of MAPK or PI3K activity reversed IL-6- and oncostatin M-stimulated migration. Because cross-talk between cytokine receptors and members of the ErbB family of receptor tyrosine kinases has been described previously, we have examined their interaction in T47D cells. Down-regulation of ErbB receptor activity, through the use of specific pharmacological inhibitors or dominant negative receptor constructs, revealed that IL-6-induced MAPK activation was largely dependent on epidermal growth factor (EGF) receptor activity, but not on ErbB-2 activity. Using a monoclonal antibody that interferes with EGF receptor-ligand interaction, we have shown that in T47D cells, IL-6 cooperates with an EGF receptor autocrine activity loop for signaling through the MAPK and PI3K pathways and for cell migration. Both the tyrosine phosphatase SHP-2 and the multisubstrate docking molecule Gab1, which are potential links between IL-6 and the MAPK/PI3K pathways, were constitutively associated with the active EGF receptor. On IL-6 stimulation, SHP-2 and Gab1 were recruited to the gp130 subunit of the IL-6 receptor and tyrosine phosphorylated, allowing downstream signaling to the MAPK and PI3K pathways. Thus, in T47D breast carcinoma cells, IL-6 acts in synergy with EGF receptor autocrine activity to signal through the MAPK/PI3K pathways. Cooperation between IL-6 and the EGF receptor in T47D breast carcinoma cells illustrates how a combination of multiple stimuli, either exogenous or endogenous, may result in synergistic cellular responses.

An Eph receptor sperm-sensing control mechanism for oocyte meiotic maturation in Caenorhabditis elegans.

PubMed

Miller, Michael A; Ruest, Paul J; Kosinski, Mary; Hanks, Steven K; Greenstein, David

2003-01-15

During sexual reproduction in most animals, oocytes arrest in meiotic prophase and resume meiosis (meiotic maturation) in response to sperm or somatic cell signals. Despite progress in delineating mitogen-activated protein kinase (MAPK) and CDK/cyclin activation pathways involved in meiotic maturation, it is less clear how these pathways are regulated at the cell surface. The Caenorhabditis elegans major sperm protein (MSP) signals oocytes, which are arrested in meiotic prophase, to resume meiosis and ovulate. We used DNA microarray data and an in situ binding assay to identify the VAB-1 Eph receptor protein-tyrosine kinase as an MSP receptor. We show that VAB-1 and a somatic gonadal sheath cell-dependent pathway, defined by the CEH-18 POU-class homeoprotein, negatively regulate meiotic maturation and MAPK activation. MSP antagonizes these inhibitory signaling circuits, in part by binding VAB-1 on oocytes and sheath cells. Our results define a sperm-sensing control mechanism that inhibits oocyte maturation, MAPK activation, and ovulation when sperm are unavailable for fertilization. MSP-domain proteins are found in diverse animal taxa, where they may regulate contact-dependent Eph receptor signaling pathways.

Evaluation of Signaling Pathways Involved in γ-Globin Gene Induction Using Fetal Hemoglobin Inducer Drugs.

PubMed

Rahim, Fakher; Allahmoradi, Hossein; Salari, Fatemeh; Shahjahani, Mohammad; Fard, Ali Dehghani; Hosseini, Seyed Ahmad; Mousakhani, Hadi

2013-01-01

Potent induction of fetal hemoglobin (HbF) production results in alleviating the complications of β-thalassemia and sickle cell disease (SCD). HbF inducer agents can trigger several molecular signaling pathways critical for erythropoiesis. Janus kinase/Signal transducer and activator of transcription (JAK/STAT), mitogen activated protein kinas (MAPK) and Phosphoinositide 3-kinase (PI3K) are considered as main signaling pathways, which may play a significant role in HbF induction. All these signaling pathways are triggered by erythropoietin (EPO) as the main growth factor inducing erythroid differentiation, when it binds to its cell surface receptor, erythropoietin receptor (EPO-R) HbF inducer agents have been shown to upregulate HbF production level by triggering certain signaling pathways. As a result, understanding the pivotal signaling pathways influencing HbF induction leads to effective upregulation of HbF. In this mini review article, we try to consider the correlation between HbF inducer agents and their molecular mechanisms of γ-globin upregulation. Several studies suggest that activating P38 MAPK, RAS and STAT5 signaling pathways result in efficient HbF induction. Nevertheless, the role of other erythroid signaling pathways in HbF induction seems to be indispensible and should be emphasized.

Ultrasound Stimulation of Different Dental Stem Cell Populations: Role of Mitogen-activated Protein Kinase Signaling.

PubMed

Gao, Qianhua; Walmsley, A Damien; Cooper, Paul R; Scheven, Ben A

2016-03-01

Mesenchymal stem cells (MSCs) from dental tissues may respond to low-intensity pulsed ultrasound (LIPUS) treatment, potentially providing a therapeutic approach to promoting dental tissue regeneration. This work aimed to compare LIPUS effects on the proliferation and MAPK signaling in MSCs from rodent dental pulp stem cells (DPSCs) compared with MSCs from periodontal ligament stem cells (PDLSCs) and bone marrow stem cells (BMSCs). Isolated MSCs were treated with 1-MHz LIPUS at an intensity of 250 or 750 mW/cm2 for 5 or 20 minutes. Cell proliferation was evaluated by 5-bromo-2-deoxyuridine (BrdU) staining after 24 hours of culture following a single LIPUS treatment. Specific ELISAs were used to determine the total and activated p38, ERK1/2, and JNK MAPK signaling proteins up to 4 hours after treatment. Selective MAPK inhibitors PD98059 (ERK1/2), SB203580 (p38), and SP600125 (JNK) were used to determine the role of activation of the particular MAPK pathways. The proliferation of all MSC types was significantly increased after LIPUS treatment. LIPUS at a 750-mW/cm2 dose induced the greatest effects on DPSCs. BMSC proliferation was stimulated in equal measures by both intensities, whereas 250 mW/cm2 LIPUS exposure exerted maximum effects on PDLSCs. ERK1/2 was activated immediately in DPSCs after treatment. Concomitantly, DPSC proliferation was specifically modulated by ERK1/2 inhibition, whereas p38 and JNK inhibition exerted no effects. In BMSCs, JNK MAPK signaling was LIPUS activated, and the increase in proliferation was blocked by specific inhibition of the JNK pathway. In PDLSCs, JNK MAPK signaling was activated immediately after LIPUS, whereas p-p38 MAPK increased significantly in these cells 4 hours after exposure. Correspondingly, JNK and p38 inhibition modulated LIPUS-stimulated PDLSC proliferation. LIPUS promoted MSC proliferation in an intensity and cell-specific dependent manner via activation of distinct MAPK pathways. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Signaling Pathways Involved in the Regulation of mRNA Translation

PubMed Central

2018-01-01

ABSTRACT Translation is a key step in the regulation of gene expression and one of the most energy-consuming processes in the cell. In response to various stimuli, multiple signaling pathways converge on the translational machinery to regulate its function. To date, the roles of phosphoinositide 3-kinase (PI3K)/AKT and the mitogen-activated protein kinase (MAPK) pathways in the regulation of translation are among the best understood. Both pathways engage the mechanistic target of rapamycin (mTOR) to regulate a variety of components of the translational machinery. While these pathways regulate protein synthesis in homeostasis, their dysregulation results in aberrant translation leading to human diseases, including diabetes, neurological disorders, and cancer. Here we review the roles of the PI3K/AKT and MAPK pathways in the regulation of mRNA translation. We also highlight additional signaling mechanisms that have recently emerged as regulators of the translational apparatus. PMID:29610153

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. Copyright © 2016 Elsevier B.V. All rights reserved.

Loss of EGFR confers acquired resistance to AZD9291 in an EGFR-mutant non-small cell lung cancer cell line with an epithelial-mesenchymal transition phenotype.

PubMed

Xu, Jing; Zhao, Xiaoting; He, Dengfeng; Wang, Jinghui; Li, Weiying; Liu, Yinghui; Ma, Li; Jiang, Mei; Teng, Yu; Wang, Ziyu; Gu, Meng; Wu, Jianbin; Wang, Yue; Yue, Wentao; Zhang, Shucai

2018-05-24

AZD9291 is an irreversible, small-molecule inhibitor which has potency against mutant EGFR- and T790M-resistant mutation. Despite the encouraging efficacy in clinical, the acquired resistance will finally occur. Further study will need to be done to identify the acquired resistance mechanisms and determine the next treatment. We established an AZD9291-resistant cell line (HCC827/AZDR) from parental HCC827 cell line through stepwise pulsed selection of AZD9291. The expression of EGFR and its downstream pathways were determined by western blot analysis or immunofluorescence assay. The sensitivity to indicated agents were evaluated by MTS. Compared with parental HCC827 cells, the HCC827/AZDR cells showed high resistance to AZD9291 and other EGFR-TKIs, and exhibited a mesenchymal-like phenotype. Almost complete loss of EGFR expression was observed in HCC827/AZDR cells. But the activation of downstream pathway, MAPK signaling, was found in HCC827/AZDR cells even in the presence of AZD9291. Inhibition of MAPK signaling had no effect on cell viability of HCC827/AZDR and could not reverse AZD9291 resistance because of the subsequent activation of AKT signaling. When treated with the combination of AKT and MAPK inhibitor, HCC827/AZDR showed remarkable growth inhibition. Loss of EGFR could be proposed as a potential acquired resistance mechanism of AZD9291 in EGFR-mutant NSCLC cells with an EMT phenotype. Despite the loss of EGFR, the activation of MAPK pathway which had crosstalk with AKT pathway could maintain the proliferation and survival of resistant cells. Blocking MAPK and AKT signaling may be a potential therapeutic strategy following AZD9291 resistance.

Small molecule stabilization of the KSR inactive state antagonizes oncogenic Ras signalling

PubMed Central

Dhawan, Neil S.; scopton, Alex P.; Dar, Arvin C.

2016-01-01

Deregulation of the Ras–mitogen activated protein kinase (MAPK) pathway is an early event in many different cancers and a key driver of resistance to targeted therapies1. Sustained signalling through this pathway is caused most often by mutations in K-Ras, which biochemically favours the stabilization of active RAF signalling complexes2. Kinase suppressor of Ras (KSR) is a MAPK scaffold3–5 that is subject to allosteric regulation through dimerization with RAF6,7. Direct targeting of KSR could have important therapeutic implications for cancer; however, testing this hypothesis has been difficult owing to a lack of small-molecule antagonists of KSR function. Guided by KSR mutations that selectively suppress oncogenic, but not wild-type, Ras signalling, we developed a class of compounds that stabilize a previously unrecognized inactive state of KSR. These compounds, exemplified by APS-2-79, modulate KSR-dependent MAPK signalling by antagonizing RAF heterodimerization as well as the conformational changes required for phosphorylation and activation of KSR-bound MEK (mitogen-activated protein kinase kinase). Furthermore, APS-2-79 increased the potency of several MEK inhibitors specifically within Ras-mutant cell lines by antagonizing release of negative feedback signalling, demonstrating the potential of targeting KSR to improve the efficacy of current MAPK inhibitors. These results reveal conformational switching in KSR as a druggable regulator of oncogenic Ras, and further suggest co-targeting of enzymatic and scaffolding activities within Ras–MAPK signalling complexes as a therapeutic strategy for overcoming Ras-driven cancers. PMID:27556948

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

PubMed

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

2005-05-24

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

Crosstalk between Signaling Pathways in Pemphigus: A Role for Endoplasmic Reticulum Stress in p38 Mitogen-Activated Protein Kinase Activation?

PubMed

Cipolla, Gabriel A; Park, Jong Kook; Lavker, Robert M; Petzl-Erler, Maria Luiza

2017-01-01

Pemphigus consists of a group of chronic blistering skin diseases mediated by autoantibodies (autoAbs). The dogma that pemphigus is caused by keratinocyte dissociation (acantholysis) as a distinctive and direct consequence of the presence of autoAb targeting two main proteins of the desmosome-desmoglein (DSG) 1 and/or DSG3-has been put to the test. Several outside-in signaling events elicited by pemphigus autoAb in keratinocytes have been described, among which stands out p38 mitogen-activated protein kinase (p38 MAPK) engagement and its apoptotic effect on keratinocytes. The role of apoptosis in the disease is, however, debatable, to an extent that it may not be a determinant event for the occurrence of acantholysis. Also, it has been verified that compromised DSG trans-interaction does not lead to keratinocyte dissociation when p38 MAPK is inhibited. These examples of conflicting results have been followed by recent work revealing an important role for endoplasmic reticulum (ER) stress in pemphigus' pathogenesis. ER stress is known to activate the p38 MAPK pathway, and vice versa . However, this relationship has not yet been studied in the context of activated signaling pathways in pemphigus. Therefore, by reviewing and hypothetically connecting the role(s) of ER stress and p38 MAPK pathway in pemphigus, we highlight the importance of elucidating the crosstalk between all activated signaling pathways, which may in turn contribute for a better understanding of the role of apoptosis in the disease and a better management of this life-threatening condition.

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

Gelidium elegans Extract Ameliorates Type 2 Diabetes via Regulation of MAPK and PI3K/Akt Signaling

PubMed Central

Choi, Jia; Kim, Kui-Jin; Koh, Eun-Jeong; Lee, Boo-Yong

2018-01-01

Gelidium elegans, a red alga native to the Asia Pacific region, contains biologically active polyphenols. We conducted a molecular biological study of the anti-diabetic effect of Gelidium elegans extract (GEE) in C57BL/KsJ-db/db mice. Mice that had been administered GEE had significantly lower body mass, water consumption, and fasting blood glucose than db/db controls. Moreover, hemoglobin A1c (HbA1c), an indicator of the glycemic status of people with diabetes, was significantly lower in mice that had been administered GEE. We also found that 200 mg/kg/day GEE upregulates the insulin signaling pathway by activating insulin receptor substrate-1 (IRS-1) and phosphoinositide 3-kinase (PI3K), and increasing the expression of glucose transporter type 4 (GLUT4). In parallel, mitogen-activated protein kinase (MAPK) activity was lower in GEE-treated groups. In summary, these findings indicate that GEE regulates glucose metabolism by activating the insulin signaling pathway and downregulating the MAPK signaling pathway. PMID:29316644

Requirement for sustained MAPK signaling in both CD4 and CD8 lineage commitment: a threshold model.

PubMed

Wilkinson, B; Kaye, J

2001-08-01

Although there is general agreement that the RAS/MAPK signaling pathway is required for positive selection of CD4 T cells in the thymus, the role of this pathway in CD8 lineage commitment remains controversial. We show here that the differentiation of isolated cultured thymocytes to the CD8 as well as CD4 T cell lineage is sensitive to MEK inhibition and that both CD4 and CD8 thymocyte differentiation requires sustained MEK signaling. However, CD4 lineage commitment is promoted by a stronger stimulus for longer duration than required for CD8 lineage commitment. Interestingly, CD4 lineage commitment is not irreversibly set even after 10 h of signaling, well past early changes in gene expression. These findings are presented in the context of a model of lineage commitment in which a default pathway of CD8 lineage commitment is altered to CD4 commitment if the thymocyte achieves a threshold level of active MAPK within a certain time frame. Copyright 2001 Academic Press.

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

PubMed Central

Adhikari, Hema; Cullen, Paul J.

2014-01-01

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

Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) activates promyogenic signaling pathways, thereby promoting myoblast differentiation

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

Lee, Sang-Jin; Go, Ga-Yeon; Yoo, Miran

Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) regulates postnatal myogenesis by alleviating myostatin activity, but the molecular mechanisms by which it regulates myogenesis are not fully understood. In this study, we investigate molecular mechanisms of PPARβ/δ in myoblast differentiation. C2C12 myoblasts treated with a PPARβ/δ agonist, GW0742 exhibit enhanced myotube formation and muscle-specific gene expression. GW0742 treatment dramatically activates promyogenic kinases, p38MAPK and Akt, in a dose-dependent manner. GW0742-stimulated myoblast differentiation is mediated by p38MAPK and Akt, since it failed to restore myoblast differentiation repressed by inhibition of p38MAPK and Akt. In addition, GW0742 treatment enhances MyoD-reporter activities. Consistently, overexpression of PPARβ/δmore » enhances myoblast differentiation accompanied by elevated activation of p38MAPK and Akt. Collectively, these results suggest that PPARβ/δ enhances myoblast differentiation through activation of promyogenic signaling pathways. - Highlights: • A PPARβ/δ agonist, GW0742 promotes myoblast differentiation. • GW0742 activates both p38MAPK and Akt activation in myogenic differentiation. • GW0742 enhances MyoD activity for myogenic differentiation. • Overexpression of PPARβ/δ enhances myoblast differentiation via activating promyogenic signaling pathways. • This is the first finding for agonistic mechanism of PPARβ/δ in myogenesis.« less

MiRNA-335 suppresses neuroblastoma cell invasiveness by direct targeting of multiple genes from the non-canonical TGF-β signalling pathway

PubMed Central

Lynch, Jennifer; Fay, Joanna; Meehan, Maria; Bryan, Kenneth; Watters, Karen M.; Murphy, Derek M.; Stallings, Raymond L.

2012-01-01

Transforming growth factor-β (TGF-β) signaling regulates many diverse cellular activities through both canonical (SMAD-dependent) and non-canonical branches, which includes the mitogen-activated protein kinase (MAPK), Rho-like guanosine triphosphatase and phosphatidylinositol-3-kinase/AKT pathways. Here, we demonstrate that miR-335 directly targets and downregulates genes in the TGF-β non-canonical pathways, including the Rho-associated coiled-coil containing protein (ROCK1) and MAPK1, resulting in reduced phosphorylation of downstream pathway members. Specifically, inhibition of ROCK1 and MAPK1 reduces phosphorylation levels of the motor protein myosin light chain (MLC) leading to a significant inhibition of the invasive and migratory potential of neuroblastoma cells. Additionally, miR-335 targets the leucine-rich alpha-2-glycoprotein 1 (LRG1) messenger RNA, which similarly results in a significant reduction in the phosphorylation status of MLC and a decrease in neuroblastoma cell migration and invasion. Thus, we link LRG1 to the migratory machinery of the cell, altering its activity presumably by exerting its effect within the non-canonical TGF-β pathway. Moreover, we demonstrate that the MYCN transcription factor, whose coding sequence is highly amplified in a particularly clinically aggressive neuroblastoma tumor subtype, directly binds to a region immediately upstream of the miR-335 transcriptional start site, resulting in transcriptional repression. We conclude that MYCN contributes to neuroblastoma cell migration and invasion, by directly downregulating miR-335, resulting in the upregulation of the TGF-β signaling pathway members ROCK1, MAPK1 and putative member LRG1, which positively promote this process. Our results provide novel insight into the direct regulation of TGF-β non-canonical signaling by miR-335, which in turn is downregulated by MYCN. PMID:22382496

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

Phyllanthus Suppresses Prostate Cancer Cell, PC-3, Proliferation and Induces Apoptosis through Multiple Signalling Pathways (MAPKs, PI3K/Akt, NFκB, and Hypoxia).

PubMed

Tang, Yin-Quan; Jaganath, Indubala; Manikam, Rishya; Sekaran, Shamala Devi

2013-01-01

Phyllanthus is a traditional medicinal plant that has been found to have antihepatitis, antibacterial, and anticancer properties. The present studies were to investigate the in vitro molecular mechanisms of anticancer effects of Phyllanthus (P. amarus, P. niruri, P. urinaria, and P. watsonii) plant extracts in human prostate adenocarcinoma. The cancer ten-pathway reporter array was performed and revealed that the expression of six pathway reporters were significantly decreased (Wnt, NFκB, Myc/Max, hypoxia, MAPK/ERK, and MAPK/JNK) in PC-3 cells after treatment with Phyllanthus extracts. Western blot was conducted and identified several signalling molecules that were affected in the signalling pathways including pan-Ras, c-Raf, RSK, Elk1, c-Jun, JNK1/2, p38 MAPK, c-myc, DSH, β-catenin, Akt, HIF-1α, GSK3β, NFκB p50 and p52, Bcl-2, Bax, and VEGF, in treated PC-3 cells. A proteomics-based approach, 2D gel electrophoresis, was performed, and mass spectrometry (MS/MS) results revealed that there were 72 differentially expressed proteins identified in treated PC-3 cells and were involved in tumour cell adhesion, apoptosis, glycogenesis and glycolysis, metastasis, angiogenesis, and protein synthesis and energy metabolism. Overall, these findings suggest that Phyllanthus can interfere with multiple signalling cascades involved in tumorigenesis and be used as a potential therapeutic candidate for treatment of cancer.

Antiepileptic Effect of Uncaria rhynchophylla and Rhynchophylline Involved in the Initiation of c-Jun N-Terminal Kinase Phosphorylation of MAPK Signal Pathways in Acute Seizures of Kainic Acid-Treated Rats

PubMed Central

Hsu, Hsin-Cheng; Tang, Nou-Ying; Liu, Chung-Hsiang

2013-01-01

Seizures cause inflammation of the central nervous system. The extent of the inflammation is related to the severity and recurrence of the seizures. Cell surface receptors are stimulated by stimulators such as kainic acid (KA), which causes intracellular mitogen-activated protein kinase (MAPK) signal pathway transmission to coordinate a response. It is known that Uncaria rhynchophylla (UR) and rhynchophylline (RP) have anticonvulsive effects, although the mechanisms remain unclear. Therefore, the purpose of this study is to develop a novel strategy for treating epilepsy by investigating how UR and RP initiate their anticonvulsive mechanisms. Sprague-Dawley rats were administered KA (12 mg/kg, i.p.) to induce seizure before being sacrificed. The brain was removed 3 h after KA administration. The results indicate that pretreatment with UR (1.0 g/kg), RP (0.25 mg/kg), and valproic acid (VA, 250 mg/kg) for 3 d could reduce epileptic seizures and could also reduce the expression of c-Jun aminoterminal kinase phosphorylation (JNKp) of MAPK signal pathways in the cerebral cortex and hippocampus brain tissues. Proinflammatory cytokines interleukin (IL)-1β, IL-6, and tumor necrosis factor-α remain unchanged, indicating that the anticonvulsive effect of UR and RP is initially involved in the JNKp MAPK signal pathway during the KA-induced acute seizure period. PMID:24381640

Antiepileptic Effect of Uncaria rhynchophylla and Rhynchophylline Involved in the Initiation of c-Jun N-Terminal Kinase Phosphorylation of MAPK Signal Pathways in Acute Seizures of Kainic Acid-Treated Rats.

PubMed

Hsu, Hsin-Cheng; Tang, Nou-Ying; Liu, Chung-Hsiang; Hsieh, Ching-Liang

2013-01-01

Seizures cause inflammation of the central nervous system. The extent of the inflammation is related to the severity and recurrence of the seizures. Cell surface receptors are stimulated by stimulators such as kainic acid (KA), which causes intracellular mitogen-activated protein kinase (MAPK) signal pathway transmission to coordinate a response. It is known that Uncaria rhynchophylla (UR) and rhynchophylline (RP) have anticonvulsive effects, although the mechanisms remain unclear. Therefore, the purpose of this study is to develop a novel strategy for treating epilepsy by investigating how UR and RP initiate their anticonvulsive mechanisms. Sprague-Dawley rats were administered KA (12 mg/kg, i.p.) to induce seizure before being sacrificed. The brain was removed 3 h after KA administration. The results indicate that pretreatment with UR (1.0 g/kg), RP (0.25 mg/kg), and valproic acid (VA, 250 mg/kg) for 3 d could reduce epileptic seizures and could also reduce the expression of c-Jun aminoterminal kinase phosphorylation (JNKp) of MAPK signal pathways in the cerebral cortex and hippocampus brain tissues. Proinflammatory cytokines interleukin (IL)-1 β , IL-6, and tumor necrosis factor- α remain unchanged, indicating that the anticonvulsive effect of UR and RP is initially involved in the JNKp MAPK signal pathway during the KA-induced acute seizure period.

PSMA redirects cell survival signaling from the MAPK to the PI3K-AKT pathways to promote the progression of prostate cancer

PubMed Central

Caromile, Leslie Ann; Dortche, Kristina; Rahman, M. Mamunur; Grant, Christina L.; Stoddard, Christopher; Ferrer, Fernando A.; Shapiro, Linda H.

2017-01-01

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. PMID:28292957

Genomic and transcriptome analyses reveal that MAPK- and phosphatidylinositol-signaling pathways mediate tolerance to 5-hydroxymethyl-2-furaldehyde for industrial yeast Saccharomyces cerevisiae

PubMed Central

Zhou, Qian; Liu, Z. Lewis; Ning, Kang; Wang, Anhui; Zeng, Xiaowei; Xu, Jian

2014-01-01

The industrial yeast Saccharomyces cerevisiae is a traditional ethanologenic agent and a promising biocatalyst for advanced biofuels production using lignocellulose mateials. Here we present the genomic background of type strain NRRL Y-12632 and its transcriptomic response to 5-hydroxymethyl-2-furaldehyde (HMF), a commonly encountered toxic compound liberated from lignocellulosic-biomass pretreatment, in dissecting the genomic mechanisms of yeast tolerance. Compared with the genome of laboratory model strain S288C, we identified more than 32,000 SNPs in Y-12632 with 23,000 missense and nonsense SNPs. Enriched sequence mutations occurred for genes involved in MAPK- and phosphatidylinositol (PI)- signaling pathways in strain Y-12632, with 41 and 13 genes containing non-synonymous SNPs, respectively. Many of these mutated genes displayed consistent up-regulated signature expressions in response to challenges of 30 mM HMF. Analogous single-gene deletion mutations of these genes showed significantly sensitive growth response on a synthetic medium containing 20 mM HMF. Our results suggest at least three MAPK-signaling pathways, especially for the cell-wall integrity pathway, and PI-signaling pathways to be involved in mediation of yeast tolerance against HMF in industrial yeast Saccharomyces cerevisiae. Higher levels of sequence variations were also observed for genes involved in purine and pyrimidine metabolism pathways. PMID:25296911

Response to Hyperosmotic Stress

PubMed Central

Saito, Haruo; Posas, Francesc

2012-01-01

An appropriate response and adaptation to hyperosmolarity, i.e., an external osmolarity that is higher than the physiological range, can be a matter of life or death for all cells. It is especially important for free-living organisms such as the yeast Saccharomyces cerevisiae. When exposed to hyperosmotic stress, the yeast initiates a complex adaptive program that includes temporary arrest of cell-cycle progression, adjustment of transcription and translation patterns, and the synthesis and retention of the compatible osmolyte glycerol. These adaptive responses are mostly governed by the high osmolarity glycerol (HOG) pathway, which is composed of membrane-associated osmosensors, an intracellular signaling pathway whose core is the Hog1 MAP kinase (MAPK) cascade, and cytoplasmic and nuclear effector functions. The entire pathway is conserved in diverse fungal species, while the Hog1 MAPK cascade is conserved even in higher eukaryotes including humans. This conservation is illustrated by the fact that the mammalian stress-responsive p38 MAPK can rescue the osmosensitivity of hog1Δ mutations in response to hyperosmotic challenge. As the HOG pathway is one of the best-understood eukaryotic signal transduction pathways, it is useful not only as a model for analysis of osmostress responses, but also as a model for mathematical analysis of signal transduction pathways. In this review, we have summarized the current understanding of both the upstream signaling mechanism and the downstream adaptive responses to hyperosmotic stress in yeast. PMID:23028184

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.

Increasing Maternal Body Mass Index Is Associated with Systemic Inflammation in the Mother and the Activation of Distinct Placental Inflammatory Pathways1

PubMed Central

Aye, Irving L.M.H.; Lager, Susanne; Ramirez, Vanessa I.; Gaccioli, Francesca; Dudley, Donald J.; Jansson, Thomas; Powell, Theresa L.

2014-01-01

ABSTRACT Obese pregnant women have increased levels of proinflammatory cytokines in maternal circulation and placental tissues. However, the pathways contributing to placental inflammation in obesity are largely unknown. We tested the hypothesis that maternal body mass index (BMI) was associated with elevated proinflammatory cytokines in maternal and fetal circulations and increased activation of placental inflammatory pathways. A total of 60 women of varying pre-/early pregnancy BMI, undergoing delivery by Cesarean section at term, were studied. Maternal and fetal (cord) plasma were collected for analysis of insulin, leptin, IL-1beta, IL-6, IL-8, monocyte chemoattractant protein (MCP) 1, and TNFalpha by multiplex ELISA. Activation of the inflammatory pathways in the placenta was investigated by measuring the phosphorylated and total protein expression of p38-mitogen-activated protein kinase (MAPK), c-Jun-N-terminal kinase (JNK)-MAPK, signal transducer-activated transcription factor (STAT) 3, caspase-1, IL-1beta, IkappaB-alpha protein, and p65 DNA-binding activity. To determine the link between activated placental inflammatory pathways and elevated maternal cytokines, cultured primary human trophoblast (PHT) cells were treated with physiological concentrations of insulin, MCP-1, and TNFalpha, and inflammatory signaling analyzed by Western blot. Maternal BMI was positively correlated with maternal insulin, leptin, MCP-1, and TNFalpha, whereas only fetal leptin was increased with BMI. Placental phosphorylation of p38-MAPK and STAT3, and the expression of IL-1beta protein, were increased with maternal BMI; phosphorylation of p38-MAPK was also correlated with birth weight. In contrast, placental NFkappaB, JNK and caspase-1 signaling, and fetal cytokine levels were unaffected by maternal BMI. In PHT cells, p38-MAPK was activated by MCP-1 and TNFalpha, whereas STAT3 phosphorylation was increased following TNFalpha treatment. Maternal BMI is associated with elevated maternal cytokines and activation of placental p38-MAPK and STAT3 inflammatory pathways, without changes in fetal systemic inflammatory profile. Activation of p38-MAPK by MCP-1 and TNFalpha, and STAT3 by TNFalpha, suggests a link between elevated proinflammatory cytokines in maternal plasma and activation of placental inflammatory pathways. We suggest that inflammatory processes associated with elevated maternal BMI may influence fetal growth by altering placental function. PMID:24759787

Increasing maternal body mass index is associated with systemic inflammation in the mother and the activation of distinct placental inflammatory pathways.

PubMed

Aye, Irving L M H; Lager, Susanne; Ramirez, Vanessa I; Gaccioli, Francesca; Dudley, Donald J; Jansson, Thomas; Powell, Theresa L

2014-06-01

Obese pregnant women have increased levels of proinflammatory cytokines in maternal circulation and placental tissues. However, the pathways contributing to placental inflammation in obesity are largely unknown. We tested the hypothesis that maternal body mass index (BMI) was associated with elevated proinflammatory cytokines in maternal and fetal circulations and increased activation of placental inflammatory pathways. A total of 60 women of varying pre-/early pregnancy BMI, undergoing delivery by Cesarean section at term, were studied. Maternal and fetal (cord) plasma were collected for analysis of insulin, leptin, IL-1beta, IL-6, IL-8, monocyte chemoattractant protein (MCP) 1, and TNFalpha by multiplex ELISA. Activation of the inflammatory pathways in the placenta was investigated by measuring the phosphorylated and total protein expression of p38-mitogen-activated protein kinase (MAPK), c-Jun-N-terminal kinase (JNK)-MAPK, signal transducer-activated transcription factor (STAT) 3, caspase-1, IL-1beta, IkappaB-alpha protein, and p65 DNA-binding activity. To determine the link between activated placental inflammatory pathways and elevated maternal cytokines, cultured primary human trophoblast (PHT) cells were treated with physiological concentrations of insulin, MCP-1, and TNFalpha, and inflammatory signaling analyzed by Western blot. Maternal BMI was positively correlated with maternal insulin, leptin, MCP-1, and TNFalpha, whereas only fetal leptin was increased with BMI. Placental phosphorylation of p38-MAPK and STAT3, and the expression of IL-1beta protein, were increased with maternal BMI; phosphorylation of p38-MAPK was also correlated with birth weight. In contrast, placental NFkappaB, JNK and caspase-1 signaling, and fetal cytokine levels were unaffected by maternal BMI. In PHT cells, p38-MAPK was activated by MCP-1 and TNFalpha, whereas STAT3 phosphorylation was increased following TNFalpha treatment. Maternal BMI is associated with elevated maternal cytokines and activation of placental p38-MAPK and STAT3 inflammatory pathways, without changes in fetal systemic inflammatory profile. Activation of p38-MAPK by MCP-1 and TNFalpha, and STAT3 by TNFalpha, suggests a link between elevated proinflammatory cytokines in maternal plasma and activation of placental inflammatory pathways. We suggest that inflammatory processes associated with elevated maternal BMI may influence fetal growth by altering placental function. © 2014 by the Society for the Study of Reproduction, Inc.

Two Sulfur Glycoside Compounds Isolated from Lepidium apetalum Willd Protect NRK52e Cells against Hypertonic-Induced Adhesion and Inflammation by Suppressing the MAPK Signaling Pathway and RAAS.

PubMed

Yuan, Peipei; Zheng, Xiaoke; Li, Meng; Ke, Yingying; Fu, Yang; Zhang, Qi; Wang, Xiaolan; Feng, Weisheng

2017-11-12

Lepidium apetalum Willd has been used to reduce edema and promote urination. Cis -desulfoglucotropaeolin ( cis -DG) and trans -desulfoglucotropaeolin ( trans -DG) were isolated from Lepidium apetalum Willd, and caused a significant increase in cell viability in a hypertonic model in NRK52e cells. In the hypertonic model, cis -DG and trans -DG significantly promoted the cell viability of NRK52e cells and inhibited the elevation of Na⁺ in the supernatant, inhibited the renin-angiotensin-aldosterone (RAAS) system, significantly reduced the levels of angiotensin II (Ang II) and aldosterone (ALD), and lowered aquaporin-2 (AQP2) and Na⁺-K⁺ ATP content in renal medulla. After treatment with cis -DG and trans -DG, expression of calcineurin (CAN) and Ca/calmodulin-dependent protein kinase II (CaMK II) was decreased in renal tissue and Ca 2+ influx was inhibited, thereby reducing the secretion of transforming growth factor-β (TGFβ), reversing the increase in adhesion and inflammatory factor E-selectin and monocyte chemotactic protein 1 (MCP-1) induced by high NaCl, while reducing oxidative stress status and decreasing the expression of cyclooxygenase-2 (COX2). Furthermore, inhibition of protein kinase C (PKC) expression also contributed to these improvements. The cis -DG and trans -DG reduced the expression of p-p44/42 MAPK, p-JNK and p-p38, inhibited the phosphorylation of the MAPK signaling pathway in NRN52e cells induced by high salt, decreased the overexpression of p-p38 and p-HSP27, and inhibited the overactivation of the p38-MAPK signaling pathway, suggesting that the p38-MAPK pathway may play a vital role in the hypertonic-induced adhesion and inflammatory response. From the results of this study, it can be concluded that the mechanism of cis -DG and trans -DG may mainly be through inhibiting the p38-MAPK signaling pathway, inhibiting the excessive activation of the RAAS system, and thereby reducing adhesion and inflammatory factors.

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

PubMed

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

2014-04-01

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

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

PubMed

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

2014-10-21

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

Autoantibodies in the Autoimmune Disease Pemphigus Foliaceus Induce Blistering via p38 Mitogen-Activated Protein Kinase-Dependent Signaling in the Skin

PubMed Central

Berkowitz, Paula; Chua, Michael; Liu, Zhi; Diaz, Luis A.; Rubenstein, David S.

2008-01-01

Pemphigus foliaceus (PF) is a human autoimmune blistering disease in which a humoral immune response targeting the skin results in a loss of keratinocyte cell-cell adhesion in the superficial layers of the epidermal epithelium. In PF, desmoglein-1-specific autoantibodies induce blistering. Evidence is beginning to accumulate that activation of signaling may have an important role in the ability of pathogenic pemphigus IgGs to induce blistering and that both p38 mitogen-activated protein kinase (MAPK) and heat shock protein (HSP) 27 are part of this signaling pathway. This study was undertaken to investigate the ability of PF IgGs to activate signaling as well as the contribution of this signaling pathway to blister induction in an in vivo model of PF. Phosphorylation of both p38 MAPK and HSP25, the murine HSP27 homolog, was observed in the skin of PF IgG-treated mice. Furthermore, inhibition of p38 MAPK blocked the ability of PF IgGs to induce blistering in vivo. These results indicate that PF IgG-induced blistering is dependent on activation of p38 MAPK in the target keratinocyte. Rather than influencing the immune system, limiting the autoantibody-induced intracellular signaling response that leads to target end-organ damage may be a more viable therapeutic strategy for the treatment of autoimmune diseases. Inhibition of p38 MAPK may be an effective strategy for the treatment of PF. PMID:18988808

Murine Polyomavirus Cell Surface Receptors Activate Distinct Signaling Pathways Required for Infection.

PubMed

O'Hara, Samantha D; Garcea, Robert L

2016-11-01

Virus binding to the cell surface triggers an array of host responses, including activation of specific signaling pathways that facilitate steps in virus entry. Using mouse polyomavirus (MuPyV), we identified host signaling pathways activated upon virus binding to mouse embryonic fibroblasts (MEFs). Pathways activated by MuPyV included the phosphatidylinositol 3-kinase (PI3K), FAK/SRC, and mitogen-activated protein kinase (MAPK) pathways. Gangliosides and α4-integrin are required receptors for MuPyV infection. MuPyV binding to both gangliosides and the α4-integrin receptors was required for activation of the PI3K pathway; however, either receptor interaction alone was sufficient for activation of the MAPK pathway. Using small-molecule inhibitors, we confirmed that the PI3K and FAK/SRC pathways were required for MuPyV infection, while the MAPK pathway was dispensable. Mechanistically, the PI3K pathway was required for MuPyV endocytosis, while the FAK/SRC pathway enabled trafficking of MuPyV along microtubules. Thus, MuPyV interactions with specific cell surface receptors facilitate activation of signaling pathways required for virus entry and trafficking. Understanding how different viruses manipulate cell signaling pathways through interactions with host receptors could lead to the identification of new therapeutic targets for viral infection. Virus binding to cell surface receptors initiates outside-in signaling that leads to virus endocytosis and subsequent virus trafficking. How different viruses manipulate cell signaling through interactions with host receptors remains unclear, and elucidation of the specific receptors and signaling pathways required for virus infection may lead to new therapeutic targets. In this study, we determined that gangliosides and α4-integrin mediate mouse polyomavirus (MuPyV) activation of host signaling pathways. Of these pathways, the PI3K and FAK/SRC pathways were required for MuPyV infection. Both the PI3K and FAK/SRC pathways have been implicated in human diseases, such as heart disease and cancer, and inhibitors directed against these pathways are currently being investigated as therapies. It is possible that these pathways play a role in human PyV infections and could be targeted to inhibit PyV infection in immunosuppressed patients. Copyright © 2016 O’Hara and Garcea.

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

PubMed Central

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

2012-01-01

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

Alpinia oxyphylla Miquel fruit extract activates MAPK-mediated signaling of PAs and MMP2/9 to induce Schwann cell migration and nerve regeneration.

PubMed

Chang, Yung-Ming; Ye, Chi-Xin; Ho, Tsung-Jung; Tsai, Te-Neng; Chiu, Ping-Ling; Tsai, Chin-Chuan; Lin, Yueh-Min; Kuo, Chia-Hua; Tsai, Fuu-Jen; Tsai, Chang-Hai; Huang, Chih-Yang

2014-05-01

This study investigates the molecular mechanisms by which Alpiniae oxyphyllae fructus (AOF) promotes neuron regeneration. A piece of silicone rubber was guided across a 15 mm gap in the sciatic nerve of a rat. This nerve gap was then filled with different concentrations of AOF extract (0-200 mg/ml). We investigated the role of MAPK (ERK1/2, JNK and p38) pathways for AOF-induced matrix-degrading proteolytic enzyme (PAs and MMP2/9) production in RSC96 Schwann cells. The results showed that AOF increased the expressions of uPA, tPA, MMP-9, and MAPKs in vivo. In vitro, our results show that treatment with AOF extract induces ERK1/2, JNK, and p38 phosphorylation to activate the downstream PAs and MMPs signaling expression. AOF-stimulated ERK1/2, JNK, and p38 phosphorylation attenuated by individual pretreatment with siRNAs or inhibitors (U0126, SP600125 and SB203580), resulting in migration and uPA-related signal pathway inhibition. Taken together our data suggests the MAPKs (ERK1/2, JNK and p38), PAs (uPA, tPA), MMP (MMP2, MMP9) regenerative and migration signaling pathway of Schwann cells regulated by AOF extract might play a major role in Schwann cell migration and damaged peripheral nerve regeneration.

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

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

2016-01-01

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. 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). 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. 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 inhibition of the cytochrome c-mediated caspase-3-dependent apoptotic pathway in the cortical penumbra 7 d after reperfusion.

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 inhibition of the cytochrome c-mediated caspase-3-dependent apoptotic pathway in the cortical penumbra 7 d after reperfusion. PMID:27187745

The diurnal oscillation of MAP (mitogen-activated protein) kinase and adenylyl cyclase activities in the hippocampus depends on the suprachiasmatic nucleus.

PubMed

Phan, Trongha X; Phan, Trongha H; Chan, Guy C-K; Sindreu, Carlos B; Eckel-Mahan, Kristin L; Storm, Daniel R

2011-07-20

Consolidation of hippocampus-dependent memory is dependent on activation of the cAMP/Erk/MAPK (mitogen-activated protein kinase) signal transduction pathway in the hippocampus. Recently, we discovered that adenylyl cyclase and MAPK activities undergo a circadian oscillation in the hippocampus and that inhibition of this oscillation impairs contextual memory. This suggests the interesting possibility that the persistence of hippocampus-dependent memory depends upon the reactivation of MAPK in the hippocampus during the circadian cycle. A key unanswered question is whether the circadian oscillation of this signaling pathway is intrinsic to the hippocampus or is driven by the master circadian clock in the suprachiasmatic nucleus (SCN). To address this question, we ablated the SCN of mice by electrolytic lesion and examined hippocampus-dependent memory as well as adenylyl cyclase and MAPK activities. Electrolytic lesion of the SCN 2 d after training for contextual fear memory reduced contextual memory measured 2 weeks after training, indicating that maintenance of contextual memory depends on the SCN. Spatial memory was also compromised in SCN-lesioned mice. Furthermore, the diurnal oscillation of adenylyl cyclase and MAPK activities in the hippocampus was destroyed by lesioning of the SCN. These data suggest that hippocampus-dependent long-term memory is dependent on the SCN-controlled oscillation of the adenylyl cyclase/MAPK pathway in the hippocampus.

The Diurnal Oscillation of MAP Kinase and Adenylyl Cyclase Activities in the Hippocampus Depends on the SCN

PubMed Central

Phan, Trongha; Chan, Guy; Sindreu, Carlos; Eckel-Mahan, Kristin; Storm, Daniel R.

2011-01-01

Consolidation of hippocampus dependent memory is dependent on activation of the cAMP/ Erk/MAPK signal transduction pathway in the hippocampus. Recently, we discovered that adenylyl cyclase and MAPK activities undergo a circadian oscillation in the hippocampus and that inhibition of this oscillation impairs contextual memory. This suggests the interesting possibility that the persistence of hippocampus-dependent memory depends upon the reactivation of MAPK in the hippocampus during the circadian cycle. A key unanswered question is whether the circadian oscillation of this signaling pathway is intrinsic to the hippocampus or is driven by the master circadian clock in the suprachiasmatic nucleus (SCN). To address this question, we ablated the SCN of mice by electrolytic lesion and examined hippocampus-dependent memory as well as adenylyl cyclase and MAPK activities. Electrolytic lesion of the SCN two days after training for contextual fear memory reduced contextual memory measured two weeks after training indicating that maintenance of contextual memory depends on the SCN. Spatial memory was also compromised in SCN-lesioned mice. Furthermore, the diurnal oscillation of adenylyl cyclase and MAPK activities in the hippocampus was destroyed by lesioning of the SCN. These data suggest that hippocampus-dependent long-term memory is dependent on the SCN-controlled oscillation of the adenylyl cyclase/MAPK pathway in the hippocampus. PMID:21775607

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.

RIP2 Is a Critical Regulator for NLRs Signaling and MHC Antigen Presentation but Not for MAPK and PI3K/Akt Pathways.

PubMed

Wu, Xiao Man; Chen, Wen Qin; Hu, Yi Wei; Cao, Lu; Nie, Pin; Chang, Ming Xian

2018-01-01

RIP2 is an adaptor protein which is essential for the activation of NF-κB and NOD1- and NOD2-dependent signaling. Although NOD-RIP2 axis conservatively existed in the teleost, the function of RIP2 was only reported in zebrafish, goldfish, and rainbow trout in vitro . Very little is known about the role and mechanisms of piscine NOD-RIP2 axis in vivo . Our previous study showed the protective role of zebrafish NOD1 in larval survival through CD44a-mediated activation of PI3K-Akt signaling. In this study, we examined whether RIP2 was required for larval survival with or without pathogen infection, and determined the signaling pathways modulated by RIP2. Based on our previous report and the present study, our data demonstrated that NOD1-RIP2 axis was important for larval survival in the early ontogenesis. Similar to NOD1, RIP2 deficiency significantly affected immune system processes. The significantly enriched pathways were mainly involved in immune system, such as "Antigen processing and presentation" and "NOD-like receptor signaling pathway" and so on. Furthermore, both transcriptome analysis and qRT-PCR revealed that RIP2 was a critical regulator for expression of NLRs (NOD-like receptors) and those genes involved in MHC antigen presentation. Different from NOD1, the present study showed that NOD1, but not RIP2 deficiency significantly impaired protein levels of MAPK pathways. Although RIP2 deficiency also significantly impaired the expression of CD44a, the downstream signaling of CD44a-Lck-PI3K-Akt pathway remained unchanged. Collectively, our works highlight the similarity and discrepancy of NOD1 and RIP2 in the regulation of immune signaling pathways in the zebrafish early ontogenesis, and confirm the crucial role of RIP2 in NLRs signaling and MHC antigen presentation, but not for MAPK and PI3K/Akt pathways.

PKR is a novel functional direct player that coordinates skeletal muscle differentiation via p38MAPK/AKT pathways.

PubMed

Alisi, A; Spaziani, A; Anticoli, S; Ghidinelli, M; Balsano, C

2008-03-01

Myogenic differentiation is a highly orchestrated multistep process controlled by extracellular growth factors that modulate largely unknown signals into the cell affecting the muscle-transcription program. P38MAPK-dependent signalling, as well as PI3K/Akt pathway, has a key role in the control of muscle gene expression at different stages during the myogenic process. P38MAPK affects the activities of transcription factors, such as MyoD and myogenin, and contributes, together with PI3K/Akt pathway, to control the early and late steps of myogenic differentiation. The aim of our work was to better define the role of PKR, a dsRNA-activated protein kinase, as potential component in the differentiation program of C2C12 murine myogenic cells and to correlate its activity with p38MAPK and PI3K/Akt myogenic regulatory pathways. Here, we demonstrate that PKR is an essential component of the muscle development machinery and forms a functional complex with p38MAPK and/or Akt, contributing to muscle differentiation of committed myogenic cells in vitro. Inhibition of endogenous PKR activity by a specific (si)RNA and a PKR dominant-negative interferes with the myogenic program of C2C12 cells, causing a delay in activation of myogenic specific genes and inducing the formation of thinner myofibers. In addition, the construction of three PKR mutants allowed us to demonstrate that both N and C-terminal regions of PKR are critical for the interaction with p38MAPK and Akt. The novel discovered complex permits PKR to timely regulate the inhibition/activation of p38MAPK and Akt, controlling in this way the different steps characterizing skeletal muscle differentiation.

Ischemic time impacts biological integrity of phospho-proteins in PI3K/Akt, Erk/MAPK, and p38 MAPK signaling networks.

PubMed

Holzer, Timothy R; Fulford, Angie D; Arkins, Austin M; Grondin, Janet M; Mundy, Christopher W; Nasir, Aejaz; Schade, Andrew E

2011-06-01

Post-translational modifications of proteins, such as phosphorylation, are labile events dynamically regulated by opposing kinase and phosphatase activities. Preanalytical factors, such as ischemic time before fixation, affect these activities and can have a significant impact on the ability to elucidate signaling pathways in tissue. Immunohistochemical analysis of phosphorylated proteins involved in PI3K/Akt, Erk/MAPK, and p38 MAPK signaling networks was performed in human cell line xenografts from lung, brain, ovary, and prostate tumors. In order to replicate real-world practices, the tissues were subjected to ischemic times of 0 (baseline), 1, 4, and 24 hours before fixation in formalin. Two key concepts emerge from this analysis: (1) the stability of different phospho-epitopes within a given tumor type is variable (e.g. phospho-PRAS40 is more labile than phospho-S6 ribosomal protein) and (2) the stability of a given phospho-epitope (e.g. phospho-MAPKAPK2) varies significantly across different tumor types. These results highlight the importance of proper tissue acquisition and rapid fixation to preserve the biological integrity of signal transduction pathways that may guide therapeutic decision making.

Targeted Quantification of Phosphorylation Dynamics in the Context of EGFR-MAPK Pathway.

PubMed

Yi, Lian; Shi, Tujin; Gritsenko, Marina A; X'avia Chan, Chi-Yuet; Fillmore, Thomas L; Hess, Becky M; Swensen, Adam C; Liu, Tao; Smith, Richard D; Wiley, H Steven; Qian, Wei-Jun

2018-04-17

Large-scale phosphoproteomics with coverage of over 10,000 sites of phosphorylation have now been routinely achieved with advanced mass spectrometry (MS)-based workflows. However, accurate targeted MS-based quantification of phosphorylation dynamics, an important direction for gaining quantitative understanding of signaling pathways or networks, has been much less investigated. Herein, we report an assessment of the targeted workflow in the context of signal transduction pathways, using the epidermal growth factor receptor (EGFR)-mitogen-activated protein kinase (MAPK) pathway as our model. A total of 43 phosphopeptides from the EGFR-MAPK pathway were selected for the study. The recovery and sensitivity of two commonly used enrichment methods, immobilized metal affinity chromatography (IMAC) and titanium oxide (TiO 2 ), combined with selected reaction monitoring (SRM)-MS were evaluated. The recovery of phosphopeptides by IMAC and TiO 2 enrichment was quantified to be 38 ± 5% and 58 ± 20%, respectively, based on internal standards. Moreover, both enrichment methods provided comparable sensitivity from 1 to 100 μg starting peptides. Robust quantification was consistently achieved for most targeted phosphopeptides when starting with 25-100 μg peptides. However, the numbers of quantified targets significantly dropped when peptide samples were in the 1-25 μg range. Finally, IMAC-SRM was applied to quantify signaling dynamics of EGFR-MAPK pathway in Hs578T cells following 10 ng/mL EGF treatment. The kinetics of phosphorylation clearly revealed early and late phases of phosphorylation, even for very low abundance proteins. These results demonstrate the feasibility of robust targeted quantification of phosphorylation dynamics for specific pathways, even starting with relatively small amounts of protein.

Targeted Quantification of Phosphorylation Dynamics in the Context of EGFR-MAPK Pathway

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

Yi, Lian; Shi, Tujin; Gritsenko, Marina A.

2018-03-27

Large-scale phosphoproteomics with coverage of over 10,000 sites of phosphorylation have now been routinely achieved with advanced mass spectrometry (MS)-based workflows. However, accurate targeted MS-based quantification of phosphorylation dynamics, an important direction for gaining quantitative understanding of signaling pathways or networks, has been much less investigated. Herein, we report an assessment of the targeted workflow in the context of signal transduction pathways, using the epidermal growth factor receptor (EGFR)–mitogen-activated protein kinase (MAPK) pathway as our model. 43 phosphopeptides from the EGFR–MAPK pathway were selected for the study. The recovery and sensitivity of a workflow consisted of two commonly used enrichmentmore » methods, immobilized metal affinity chromatography (IMAC) and titanium oxide (TiO2), combined with selected reaction monitoring (SRM)-MS, were evaluated. The recovery of phosphopeptides by IMAC and TiO2 enrichment was quantified to be 38 ± 5% and 58 ± 20%, respectively, based on internal standards. Moreover, both enrichment methods provided comparable sensitivity from 1-100 g starting peptides. Robust quantification was consistently achieved for most targeted phosphopeptides when starting with 25-100 g peptides. However, the numbers of quantified targets significantly dropped when peptide samples were in the 1-25g range. Finally, IMAC-SRM was applied to quantify signaling dynamics of EGFR-MAPK pathway in Hs578T cells following 3 ng/mL EGF treatment. The kinetics of phosphorylation clearly revealed early and late phases of phosphorylation, even for very low abundance proteins. These results demonstrate the feasibility of robust targeted quantification of phosphorylation dynamics for specific pathways, even starting with relatively small amounts of protein.« less

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

PubMed

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

2017-07-03

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

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.

The p38 mitogen-activated protein kinase signaling pathway is involved in regulating low-density lipoprotein receptor-related protein 1-mediated β-amyloid protein internalization in mouse brain.

PubMed

Ma, Kai-Ge; Lv, Jia; Hu, Xiao-Dan; Shi, Li-Li; Chang, Ke-Wei; Chen, Xin-Lin; Qian, Yi-Hua; Yang, Wei-Na; Qu, Qiu-Min

2016-07-01

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. Recently, increasing evidence suggests that intracellular β-amyloid protein (Aβ) alone plays a pivotal role in the progression of AD. Therefore, understanding the signaling pathway and proteins that control Aβ internalization may provide new insight for regulating Aβ levels. In the present study, the regulation of Aβ internalization by p38 mitogen-activated protein kinases (MAPK) through low-density lipoprotein receptor-related protein 1 (LRP1) was analyzed in vivo. The data derived from this investigation revealed that Aβ1-42 were internalized by neurons and astrocytes in mouse brain, and were largely deposited in mitochondria and lysosomes, with some also being found in the endoplasmic reticulum. Aβ1-42-LRP1 complex was formed during Aβ1-42 internalization, and the p38 MAPK signaling pathway was activated by Aβ1-42 via LRP1. Aβ1-42 and LRP1 were co- localized in the cells of parietal cortex and hippocampus. Furthermore, the level of LRP1-mRNA and LRP1 protein involved in Aβ1-42 internalization in mouse brain. The results of this investigation demonstrated that Aβ1-42 induced an LRP1-dependent pathway that related to the activation of p38 MAPK resulting in internalization of Aβ1-42. These results provide evidence supporting a key role for the p38 MAPK signaling pathway which is involved in the regulation of Aβ1-42 internalization in the parietal cortex and hippocampus of mouse through LRP1 in vivo. Copyright © 2016 Elsevier Ltd. All rights reserved.

Calcium alters monoamine oxidase-A parameters in human cerebellar and rat glial C6 cell extracts: possible influence by distinct signalling pathways.

PubMed

Cao, Xia; Li, Xin-Min; Mousseau, Darrell D

2009-07-31

Calcium (Ca(2+)) is known to augment monoamine oxidase-A (MAO-A) activity in cell cultures as well as in brain extracts from several species. This association between Ca(2+) and MAO-A could contribute to their respective roles in cytotoxicity. However, the effect of Ca(2+) on MAO-A function in human brain has as yet to be examined as does the contribution of specific signalling cascades. We examined the effects of Ca(2+) on MAO-A activity and on [(3)H]Ro 41-1049 binding to MAO-A in human cerebellar extracts, and compared this to its effects on MAO-A activity in glial C6 cells following the targeting of signalling pathways using specific chemical inhibitors. Ca(2+) enhances MAO-A activity as well as the association of [(3)H]Ro 41-1049 to MAO-A in human cerebellar extracts. The screening of neuronal and glial cell cultures reveals that MAO-A activity does not always correlate with the expression of either mao-A mRNA or MAO-A protein. Inhibition of the individual PI3K/Akt, ERK and p38(MAPK) signalling pathways in glial C6 cells all augment basal MAO-A activity. Inhibition of the p38(MAPK) pathway also augments Ca(2+)-sensitive MAO-A activity. We also observe the inverse relation between p38(MAPK) activation and MAO-A function in C6 cultures grown to full confluence. The Ca(2+)-sensitive component to MAO-A activity is present in human brain and in vitro studies link it to the p38(MAPK) pathway. This means of influencing MAO-A function could explain its role in pathologies as diverse as neurodegeneration and cancers.

Insulin-Like Growth Factor 1 Receptor and p38 Mitogen-Activated Protein Kinase Signals Inversely Regulate Signal Transducer and Activator of Transcription 3 Activity to Control Human Dental Pulp Stem Cell Quiescence, Propagation, and Differentiation

PubMed Central

Vandomme, Jerome; Touil, Yasmine; Ostyn, Pauline; Olejnik, Cecile; Flamenco, Pilar; El Machhour, Raja; Segard, Pascaline; Masselot, Bernadette; Bailliez, Yves; Formstecher, Pierre

2014-01-01

Dental pulp stem cells (DPSCs) remain quiescent until activated in response to severe dental pulp damage. Once activated, they exit quiescence and enter regenerative odontogenesis, producing reparative dentin. The factors and signaling molecules that control the quiescence/activation and commitment to differentiation of human DPSCs are not known. In this study, we determined that the inhibition of insulin-like growth factor 1 receptor (IGF-1R) and p38 mitogen-activated protein kinase (p38 MAPK) signaling commonly activates DPSCs and promotes their exit from the G0 phase of the cell cycle as well as from the pyronin Ylow stem cell compartment. The inhibition of these two pathways, however, inversely determines DPSC fate. In contrast to p38 MAPK inhibitors, IGF-1R inhibitors enhance dental pulp cell sphere-forming capacity and reduce the cells' colony-forming capacity without inducing cell death. The inverse cellular changes initiated by IGF-1R and p38 MAPK inhibitors were accompanied by inverse changes in the levels of active signal transducer and activator of transcription 3 (STAT3) factor, inactive glycogen synthase kinase 3, and matrix extracellular phosphoglycoprotein, a marker of early odontoblast differentiation. Our data suggest that there is cross talk between the IGF-1R and p38 MAPK signaling pathways in DPSCs and that the signals provided by these pathways converge at STAT3 and inversely regulate its activity to maintain quiescence or to promote self-renewal and differentiation of the cells. We propose a working model that explains the possible interactions between IGF-1R and p38 MAPK at the molecular level and describes the cellular consequences of these interactions. This model may inspire further fundamental study and stimulate research on the clinical applications of DPSC in cellular therapy and tissue regeneration. PMID:24266654

Genome-Wide Identification and Expression Analysis of the Mitogen-Activated Protein Kinase Gene Family in Cassava

PubMed Central

Yan, Yan; Wang, Lianzhe; Ding, Zehong; Tie, Weiwei; Ding, Xupo; Zeng, Changying; Wei, Yunxie; Zhao, Hongliang; Peng, Ming; Hu, Wei

2016-01-01

Mitogen-activated protein kinases (MAPKs) play central roles in plant developmental processes, hormone signaling transduction, and responses to abiotic stress. However, no data are currently available about the MAPK family in cassava, an important tropical crop. Herein, 21 MeMAPK genes were identified from cassava. Phylogenetic analysis indicated that MeMAPKs could be classified into four subfamilies. Gene structure analysis demonstrated that the number of introns in MeMAPK genes ranged from 1 to 10, suggesting large variation among cassava MAPK genes. Conserved motif analysis indicated that all MeMAPKs had typical protein kinase domains. Transcriptomic analysis suggested that MeMAPK genes showed differential expression patterns in distinct tissues and in response to drought stress between wild subspecies and cultivated varieties. Interaction networks and co-expression analyses revealed that crucial pathways controlled by MeMAPK networks may be involved in the differential response to drought stress in different accessions of cassava. Expression of nine selected MAPK genes showed that these genes could comprehensively respond to osmotic, salt, cold, oxidative stressors, and abscisic acid (ABA) signaling. These findings yield new insights into the transcriptional control of MAPK gene expression, provide an improved understanding of abiotic stress responses and signaling transduction in cassava, and lead to potential applications in the genetic improvement of cassava cultivars. PMID:27625666

MAPK pathway activation by chronic lead-exposure increases vascular reactivity through oxidative stress/cyclooxygenase-2-dependent pathways

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

Simões, Maylla Ronacher, E-mail: yllars@hotmail.com; Department of Pharmacology, Universidad Autonoma de Madrid, Instituto de Investigación Hospital Universitario La Paz; Aguado, Andrea

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 didmore » 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 MAPK in lead exposure • Relationship between vascular ROS and COX-2 products in lead exposure.« less

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. Copyright © 2016 Elsevier B.V. All rights reserved.

The roles of DNA damage-dependent signals and MAPK cascades in tributyltin-induced germline apoptosis in Caenorhabditis elegans.

PubMed

Wang, Yun; Wang, Shunchang; Luo, Xun; Yang, Yanan; Jian, Fenglei; Wang, Xuemin; Xie, Lucheng

2014-08-01

The induction of apoptosis is recognized to be a major mechanism of tributyltin (TBT) toxicity. However, the underlying signaling pathways for TBT-induced apoptosis remain unclear. In this study, using the nematode Caenorhabditis elegans, we examined whether DNA damage response (DDR) pathway and mitogen-activated protein kinase (MAPK) signaling cascades are involved in TBT-induced germline apoptosis and cell cycle arrest. Our results demonstrated that exposing worms to TBT at the dose of 10nM for 6h significantly increased germline apoptosis in N2 strain. Germline apoptosis was absent in strains that carried ced-3 or ced-4 loss-of-function alleles, indicating that both caspase protein CED-3 and Apaf-1 protein CED-4 were required for TBT-induced apoptosis. TBT-induced apoptosis was blocked in the Bcl-2 gain-of-function strain ced-9(n1950), whereas TBT induced a minor increase in the BH3-only protein EGL-1 mutated strain egl-1(n1084n3082). Checkpoint proteins HUS-1 and CLK-2 exerted proapoptotic effects, and the null mutation of cep-1, the homologue of tumor suppressor gene p53, significantly inhibited TBT-induced apoptosis. Apoptosis in the loss-of-function strains of ERK, JNK and p38 MAPK signaling pathways were completely or mildly suppressed under TBT stress. These results were supported by the results of mRNA expression levels of corresponding genes. The present study indicated that TBT-induced apoptosis required the core apoptotic machinery, and that DDR genes and MAPK pathways played essential roles in signaling the processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Distinctive effects of eicosapentaenoic and docosahexaenoic acids in regulating neural stem cell fate are mediated via endocannabinoid signalling pathways.

PubMed

Dyall, S C; Mandhair, H K; Fincham, R E A; Kerr, D M; Roche, M; Molina-Holgado, F

2016-08-01

Emerging evidence suggests a complex interplay between the endocannabinoid system, omega-3 fatty acids and the immune system in the promotion of brain self-repair. However, it is unknown if all omega-3 fatty acids elicit similar effects on adult neurogenesis and if such effects are mediated or regulated by interactions with the endocannabinoid system. This study investigated the effects of DHA and EPA on neural stem cell (NSC) fate and the role of the endocannabinoid signalling pathways in these effects. EPA, but not DHA, significantly increased proliferation of NSCs compared to controls, an effect associated with enhanced levels of the endocannabinoid 2-arachidonylglycerol (2-AG) and p-p38 MAPK, effects attenuated by pre-treatment with CB1 (AM251) or CB2 (AM630) receptor antagonists. Furthermore, in NSCs derived from IL-1β deficient mice, EPA significantly decreased proliferation and p-p38 MAPK levels compared to controls, suggesting a key role for IL-1β signalling in the effects observed. Although DHA similarly increased 2-AG levels in wild-type NSCs, there was no concomitant increase in proliferation or p-p38 MAPK activity. In addition, in NSCs from IL-1β deficient mice, DHA significantly increased proliferation without effects on p-P38 MAPK, suggesting effects of DHA are mediated via alternative signalling pathways. These results provide crucial new insights into the divergent effects of EPA and DHA in regulating NSC proliferation and the pathways involved, and highlight the therapeutic potential of their interplay with endocannabinoid signalling in brain repair. Copyright © 2016 Elsevier Ltd. All rights reserved.

Regulation of Schistosoma mansoni development and reproduction by the mitogen-activated protein kinase signaling pathway.

PubMed

Andrade, Luiza Freire de; Mourão, Marina de Moraes; Geraldo, Juliana Assis; Coelho, Fernanda Sales; Silva, Larissa Lopes; Neves, Renata Heisler; Volpini, Angela; Machado-Silva, José Roberto; Araujo, Neusa; Nacif-Pimenta, Rafael; Caffrey, Conor R; Oliveira, Guilherme

2014-06-01

Protein kinases are proven targets for drug development with an increasing number of eukaryotic Protein Kinase (ePK) inhibitors now approved as drugs. Mitogen-activated protein kinase (MAPK) family members connect cell-surface receptors to regulatory targets within cells and influence a number of tissue-specific biological activities such as cell proliferation, differentiation and survival. However, the contributions of members of the MAPK pathway to schistosome development and survival are unclear. We employed RNA interference (RNAi) to elucidate the functional roles of five S. mansoni genes (SmCaMK2, SmJNK, SmERK1, SmERK2 and SmRas) involved in MAPK signaling pathway. Mice were injected with post-infective larvae (schistosomula) subsequent to RNAi and the development of adult worms observed. The data demonstrate that SmJNK participates in parasite maturation and survival of the parasites, whereas SmERK are involved in egg production as infected mice had significantly lower egg burdens with female worms presenting underdeveloped ovaries. Furthermore, it was shown that the c-fos transcription factor was overexpressed in parasites submitted to RNAi of SmERK1, SmJNK and SmCaMK2 indicating its putative involvement in gene regulation in this parasite's MAPK signaling cascade. We conclude that MAPKs proteins play important roles in the parasite in vivo survival, being essential for normal development and successful survival and reproduction of the schistosome parasite. Moreover SmERK and SmJNK are potential targets for drug development.

[Role of p38MAPK/eNOS signaling pathway in the inhibition of AGEs-induced apoptosis of human umbilical vein endothelial cells by glucagon-like peptide-1].

PubMed

Zeng, Hailong; Huang, Zhiqiu; Zhang, Yineng; Sun, Huilin

2016-01-01

To investigate the role of p38MAPK signaling pathway in the mechanism by which glucagon-like peptide-1 (GLP-1) inhibits endothelial cell damage induced by AGEs. Human umbilical vein endothelial cells were divided into control group, AGEs group, GLP-1 group, AGEs+GLP-1 group, AGEs+inhibitor group, and AGEs+GLP-1+inhibitor group. The expressions of p-p38MAPK/p38MAPK and p-eNOS/eNOS protein were examined by Western blotting, and the cell apoptosis rates were tested by flow cytometry. Compared with the control group, AGEs significantly enhanced the expression of p-p38 MAPK protein (P=0.001) while GLP-1 significantly inhibited its expression (P<0.001). AGEs significantly inhibited the expression of p-eNOS protein (P=0.007), which was enhanced by GLP-1 and p38 MAPK inhibitor (SB203580) (P=0.004). Both SB203580 and GLP-1 treatment decreased the apoptosis rate of AGEs-treated cells (P<0.001). GLP-1 can protect human umbilical vein endothelial cells against AGEs-induced apoptosis partially by inhibiting the phosphorylation of p38MAPK protein and promoting the expression of p-eNOS protein.

Astragaloside IV suppresses transforming growth factor-β1 induced fibrosis of cultured mouse renal fibroblasts via inhibition of the MAPK and NF-κB signaling pathways

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

Che, Xiajing; Wang, Qin; Xie, Yuanyuan

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 inmore » 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.« less

Immunomodulatory effect of tea saponin in immune T-cells and T-lymphoma cells via regulation of Th1, Th2 immune response and MAPK/ERK2 signaling pathway.

PubMed

Bhardwaj, Jyoti; Chaudhary, Narendra; Seo, Hyo-Jin; Kim, Min-Yong; Shin, Tai-Sun; Kim, Jong-Deog

2014-06-01

The anti-cancer activity of saponins and phenolic compounds present in green tea was previously reported. However, the immunomodulatory and adjuvanticity activity of tea saponin has never been studied. In this study, we investigated the immunomodulatory effect of tea saponin in T-lymphocytes and EL4 cells via regulation of cytokine response and mitogen-activated protein kinases (MAPK) signaling pathway. Quantitative analysis of mRNA expression level of cytokines were performed by reverse transcription polymerase chain reaction following stimulation with tea saponin, ovalbumin (OVA) alone or tea saponin in combination with OVA. Tea saponin inhibited the proliferation of EL4 cells measured in a dose-dependent manner. No cytotoxicity effect of tea saponin was detected in T-lymphocytes; rather, tea saponin enhanced the proliferation of T-lymphocytes. Tea saponin with OVA increased the expression of interleukin (IL)-1, IL-2, IL-12, interferon-γ and tumor necrosis factor (TNF)-α and decreased the expression level of IL-10 and IL-8 in T-lymphocytes. Furthermore, tea saponin, in the presence of OVA, downregulated the MAPK signaling pathway via inhibition of IL-4, IL-8 and nuclear factor kappaB (NF-κB) in EL4 cells. Th1 cytokines enhancer and Th2 cytokines and NF-κB inhibitor, tea saponin can markedly inhibit the proliferation and invasiveness of T-lymphoma (EL4) cells, possibly due to TNF-α- and NF-κB-mediated regulation of MAPK signaling pathway.

KIT Suppresses BRAFV600E-Mutant Melanoma by Attenuating Oncogenic RAS/MAPK Signaling.

PubMed

Neiswender, James V; Kortum, Robert L; Bourque, Caitlin; Kasheta, Melissa; Zon, Leonard I; Morrison, Deborah K; Ceol, Craig J

2017-11-01

The receptor tyrosine kinase KIT promotes survival and migration of melanocytes during development, and excessive KIT activity hyperactivates the RAS/MAPK pathway and can drive formation of melanomas, most notably of rare melanomas that occur on volar and mucosal surfaces of the skin. The much larger fraction of melanomas that occur on sun-exposed skin is driven primarily by BRAF- or NRAS-activating mutations, but these melanomas exhibit a surprising loss of KIT expression, which raises the question of whether loss of KIT in these tumors facilitates tumorigenesis. To address this question, we introduced a kit(lf) mutation into a strain of Tg(mitfa:BRAF V600E ); p53(lf) melanoma-prone zebrafish. Melanoma onset was accelerated in kit(lf); Tg(mitfa:BRAF V600E ); p53(lf) fish. Tumors from kit(lf) animals were more invasive and had higher RAS/MAPK pathway activation. KIT knockdown also increased RAS/MAPK pathway activation in a BRAF V600E -mutant human melanoma cell line. We found that pathway stimulation upstream of BRAF V600E could paradoxically reduce signaling downstream of BRAF V600E , and wild-type BRAF was necessary for this effect, suggesting that its activation can dampen oncogenic BRAF V600E signaling. In vivo , expression of wild-type BRAF delayed melanoma onset, but only in a kit -dependent manner. Together, these results suggest that KIT can activate signaling through wild-type RAF proteins, thus interfering with oncogenic BRAF V600E -driven melanoma formation. Cancer Res; 77(21); 5820-30. ©2017 AACR . ©2017 American Association for Cancer Research.

A Drosophila model of myeloproliferative neoplasm reveals a feed-forward loop in the JAK pathway mediated by p38 MAPK signalling

PubMed Central

Pérez, Lidia; Bray, Sarah J.

2017-01-01

ABSTRACT Myeloproliferative neoplasms (MPNs) of the Philadelphia-negative class comprise polycythaemia vera, essential thrombocythaemia and primary myelofibrosis (PMF). They are associated with aberrant numbers of myeloid lineage cells in the blood, and in the case of overt PMF, with development of myelofibrosis in the bone marrow and failure to produce normal blood cells. These diseases are usually caused by gain-of-function mutations in the kinase JAK2. Here, we use Drosophila to investigate the consequences of activation of the JAK2 orthologue in haematopoiesis. We have identified maturing haemocytes in the lymph gland, the major haematopoietic organ in the fly, as the cell population susceptible to induce hypertrophy upon targeted overexpression of JAK. We show that JAK activates a feed-forward loop, including the cytokine-like ligand Upd3 and its receptor, Domeless, which are required to induce lymph gland hypertrophy. Moreover, we present evidence that p38 MAPK signalling plays a key role in this process by inducing expression of the ligand Upd3. Interestingly, we also show that forced activation of the p38 MAPK pathway in maturing haemocytes suffices to generate hypertrophic organs and the appearance of melanotic tumours. Our results illustrate a novel pro-tumourigenic crosstalk between the p38 MAPK pathway and JAK signalling in a Drosophila model of MPNs. Based on the shared molecular mechanisms underlying MPNs in flies and humans, the interplay between Drosophila JAK and p38 signalling pathways unravelled in this work might have translational relevance for human MPNs. PMID:28237966

Integrated analysis of breast cancer cell lines reveals unique signaling pathways.

PubMed

Heiser, Laura M; Wang, Nicholas J; Talcott, Carolyn L; Laderoute, Keith R; Knapp, Merrill; Guan, Yinghui; Hu, Zhi; Ziyad, Safiyyah; Weber, Barbara L; Laquerre, Sylvie; Jackson, Jeffrey R; Wooster, Richard F; Kuo, Wen Lin; Gray, Joe W; Spellman, Paul T

2009-01-01

Cancer is a heterogeneous disease resulting from the accumulation of genetic defects that negatively impact control of cell division, motility, adhesion and apoptosis. Deregulation in signaling along the EgfR-MAPK pathway is common in breast cancer, though the manner in which deregulation occurs varies between both individuals and cancer subtypes. We were interested in identifying subnetworks within the EgfR-MAPK pathway that are similarly deregulated across subsets of breast cancers. To that end, we mapped genomic, transcriptional and proteomic profiles for 30 breast cancer cell lines onto a curated Pathway Logic symbolic systems model of EgfR-MAPK signaling. This model was composed of 539 molecular states and 396 rules governing signaling between active states. We analyzed these models and identified several subtype-specific subnetworks, including one that suggested Pak1 is particularly important in regulating the MAPK cascade when it is over-expressed. We hypothesized that Pak1 over-expressing cell lines would have increased sensitivity to Mek inhibitors. We tested this experimentally by measuring quantitative responses of 20 breast cancer cell lines to three Mek inhibitors. We found that Pak1 over-expressing luminal breast cancer cell lines are significantly more sensitive to Mek inhibition compared to those that express Pak1 at low levels. This indicates that Pak1 over-expression may be a useful clinical marker to identify patient populations that may be sensitive to Mek inhibitors. All together, our results support the utility of symbolic system biology models for identification of therapeutic approaches that will be effective against breast cancer subsets.

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

PubMed Central

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

2017-01-01

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

CXCL1 inhibits airway smooth muscle cell migration through the decoy receptor Duffy antigen receptor for chemokines.

PubMed

Al-Alwan, Laila A; Chang, Ying; Rousseau, Simon; Martin, James G; Eidelman, David H; Hamid, Qutayba

2014-08-01

Airway smooth muscle cell (ASMC) migration is an important mechanism postulated to play a role in airway remodeling in asthma. CXCL1 chemokine has been linked to tissue growth and metastasis. In this study, we present a detailed examination of the inhibitory effect of CXCL1 on human primary ASMC migration and the role of the decoy receptor, Duffy AgR for chemokines (DARC), in this inhibition. Western blots and pathway inhibitors showed that this phenomenon was mediated by activation of the ERK-1/2 MAPK pathway, but not p38 MAPK or PI3K, suggesting a biased selection in the signaling mechanism. Despite being known as a nonsignaling receptor, small interference RNA knockdown of DARC showed that ERK-1/2 MAPK activation was significantly dependent on DARC functionality, which, in turn, was dependent on the presence of heat shock protein 90 subunit α. Interestingly, DARC- or heat shock protein 90 subunit α-deficient ASMCs responded to CXCL1 stimulation by enhancing p38 MAPK activation and ASMC migration through the CXCR2 receptor. In conclusion, we demonstrated DARC's ability to facilitate CXCL1 inhibition of ASMC migration through modulation of the ERK-1/2 MAPK-signaling pathway. Copyright © 2014 by The American Association of Immunologists, Inc.

Fisetin Inhibits Human Melanoma Cell Invasion through Promotion of Mesenchymal to Epithelial Transition and by Targeting MAPK and NFκB Signaling Pathways

PubMed Central

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 inhibits melanoma cell invasion through promotion of mesenchymal to epithelial transition and by targeting MAPK and NFκB signaling pathways. PMID:24466036

MEK5-ERK5 Signaling in Cancer: Implications for Targeted Therapy

PubMed Central

Hoang, Van T.; Yan, Thomas J.; Cavanaugh, Jane E.; Flaherty, Patrick T.; Beckman, Barbara S.; Burow, Matthew E.

2017-01-01

Mitogen-activated protein kinases (MAPKs) regulate diverse cellular processes including proliferation, cell survival, differentiation, and apoptosis. While conventional MAPK constituents have well-defined roles in oncogenesis, the MAPK kinase 5-extracellular signal-regulated kinase 5 (MEK5-ERK5) pathway has only recently emerged in cancer research. In this review, we consider the MEK5 signaling cascade, focusing specifically on its involvement in drug resistance and regulation of aggressive cancer phenotypes. Moreover, we explore the role of MEK5 in tumorigenesis and metastatic progression, discussing the discrepancies in preclinical studies and assessing its viability as a therapeutic target for anti-cancer agents. PMID:28153789

Activation of ERK and JNK signaling pathways by mycotoxin citrinin in human cells

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

Chang, C.-H.; Yu, F.-Y.; Wang, L.-T.

2009-06-15

Mycotoxin citrinin (CTN) is commonly found in foods and feeds that are contaminated/inoculated with Penicillium, Aspergillus and Monascus species. The exposure of human embryonic kidney (HEK293) and HeLa cells to CTN resulted in a dose-dependent increase in the phosphorylation of two major mitogen-activated protein kinases (MAPKs), ERK1/2 and JNK. In HEK293 cultures, the administering of CTN increased both the mRNA and protein levels of egr-1, c-fos and c-jun genes; additionally, the ERK1/2 pathway contributed to the upregulation of Egr-1 and c-Fos protein expression. CTN treatment also induced the transcription activity of Egr-1 and AP-1 proteins, as evidenced by luciferase reportermore » assays. Bioinformatic analyses indicated two genes Gadd45{beta} and MMP3 have Egr-1 and AP-1 response elements in their promoters, respectively. Furthermore, co-exposure of HEK293 cells to CTN and MAPK pathway inhibitors demonstrated that CTN increased the levels of Gadd45{beta} mRNA through ERK1/2 signaling pathway and up-regulated the MMP3 transcripts majorly via JNK pathway. Finally, CTN-triggered caspase 3 activity was significantly reduced in the presence of MAPK inhibitors. Our results suggest that CTN positively regulates ERK1/2 and JNK pathways as well as their downstream effectors in human cells; activated MAPK pathways are also involved in CTN-induced apoptosis.« less

Participation of MAPK, PKA and PP2A in the regulation of MPF activity in Bufo arenarum oocytes.

PubMed

Toranzo, G Sánchez; Bonilla, F; Bühler, M C Gramajo; Bühler, M I

2011-05-01

The objectives of the present paper were to study the involvement and possible interactions of both cAMP-PKA and protein phosphatases in Bufo arenarum oocyte maturation and to determine if these pathways are independent or not of the MAP kinase (MAPK) cascade. Our results indicated that the inhibition of PKA by treatment with H-89, an inhibitor of the catalytic subunit of PKA, was capable of inducing GVBD in a dose-dependent manner by a pathway in which Cdc25 phosphatase but not the MAPK cascade is involved. The injection of 50 nl of H-89 10 μM produced GVBD percentages similar to those obtained with treatment with progesterone. In addition, the assays with okadaic acid (OA), a PP2A inhibitor, significantly enhanced the percentage of oocytes that resumed meiosis by a signal transducing pathway in which the activation of the MEK-MAPK pathway is necessary, but in which Cdc25 phosphatase was not involved. Treatment with H-89, was able to overcome the inhibitory effect of PKA on GVBD; however, the inhibition of Cdc25 activity with NaVO3 was able to overcome the induction of GVBD by H-89. Although the connections between PKA and other signalling molecules that regulate oocytes maturation are still unclear, our results suggest that phosphatase Cdc25 may be the direct substrate of PKA. In Xenopus oocytes it was proposed that PP2A, a major Ser/Thr phosphatase present, is a negative regulator of Cdc2 activation. However, in Bufo arenarum oocytes, inhibition of Cdc25 with NaVO₃ did not inhibit OA-induced maturation, suggesting that the target of PP2A was not the Cdc25 phosphatase. MAPK activation has been reported to be essential in Xenopus oocytes GVBD. In B. arenarum oocytes we demonstrated that the inhibition of MAPK by PD 98059 prevented the activation of MPF induced by OA, suggesting that the activation of the MAPK cascade produced an inhibition of Myt1 and, in consequence, the activation of MPF without participation of the Cdc25 phosphatase. Our results suggest that in incompetent oocytes of B. arenarum two signal transduction pathways may be involved in the control of MPF activation: (1) the inhibition of phosphatase 2A that through the MEK-MAPK pathway regulates the activity of the Myt1; and (2) the inhibition of AMPc-PKA, which affects the activity of the Cdc25 phosphatase.

Regulation of Hippo signalling by p38 signalling

PubMed Central

Huang, Dashun; Li, Xiaojiao; Sun, Li; Huang, Ping; Ying, Hao; Wang, Hui; Wu, Jiarui; Song, Haiyun

2016-01-01

The Hippo signalling pathway has a crucial role in growth control during development, and its dysregulation contributes to tumorigenesis. Recent studies uncover multiple upstream regulatory inputs into Hippo signalling, which affects phosphorylation of the transcriptional coactivator Yki/YAP/TAZ by Wts/Lats. Here we identify the p38 mitogen-activated protein kinase (MAPK) pathway as a new upstream branch of the Hippo pathway. In Drosophila, overexpression of MAPKK gene licorne (lic), or MAPKKK gene Mekk1, promotes Yki activity and induces Hippo target gene expression. Loss-of-function studies show that lic regulates Hippo signalling in ovary follicle cells and in the wing disc. Epistasis analysis indicates that Mekk1 and lic affect Hippo signalling via p38b and wts. We further demonstrate that the Mekk1-Lic-p38b cascade inhibits Hippo signalling by promoting F-actin accumulation and Jub phosphorylation. In addition, p38 signalling modulates actin filaments and Hippo signalling in parallel to small GTPases Ras, Rac1, and Rho1. Lastly, we show that p38 signalling regulates Hippo signalling in mammalian cell lines. The Lic homologue MKK3 promotes nuclear localization of YAP via the actin cytoskeleton. Upregulation or downregulation of the p38 pathway regulates YAP-mediated transcription. Our work thus reveals a conserved crosstalk between the p38 MAPK pathway and the Hippo pathway in growth regulation. PMID:27402810

Overcoming resistance to molecularly targeted anticancer therapies: Rational drug combinations based on EGFR and MAPK inhibition for solid tumours and haematologic malignancies.

PubMed

Tortora, Giampaolo; Bianco, Roberto; Daniele, Gennaro; Ciardiello, Fortunato; McCubrey, James A; Ricciardi, Maria Rosaria; Ciuffreda, Ludovica; Cognetti, Francesco; Tafuri, Agostino; Milella, Michele

2007-06-01

Accumulating evidence suggests that cancer can be envisioned as a "signaling disease", in which alterations in the cellular genome affect the expression and/or function of oncogenes and tumour suppressor genes. This ultimately disrupts the physiologic transmission of biochemical signals that normally regulate cell growth, differentiation and programmed cell death (apoptosis). From a clinical standpoint, signal transduction inhibition as a therapeutic strategy for human malignancies has recently achieved remarkable success. However, as additional drugs move forward into the clinical arena, intrinsic and acquired resistance to "targeted" agents becomes an issue for their clinical utility. One way to overcome resistance to targeted agents is to identify genetic and epigenetic aberrations underlying sensitivity/resistance, thus enabling the selection of patients that will most likely benefit from a specific therapy. Since resistance often ensues as a result of the concomitant activation of multiple, often overlapping, signaling pathways, another possibility is to interfere with multiple, cross-talking pathways involved in growth and survival control in a rational, mechanism-based, fashion. These concepts may be usefully applied, among others, to agents that target two major signal transduction pathways: the one initiated by epidermal growth factor receptor (EGFR) signaling and the one converging on mitogen-activated protein kinase (MAPK) activation. Here, we review the molecular mechanisms of sensitivity/resistance to EGFR inhibitors, as well as the rationale for combining them with other targeted agents, in an attempt to overcome resistance. In the second part of the paper, we review MAPK-targeted agents, focusing on their therapeutic potential in haematologic malignancies, and examine the prospects for combinations of MAPK inhibitors with cytotoxic agents or other signal transduction-targeted agents to obtain synergistic anti-tumour effects.

Overcoming resistance to molecularly targeted anticancer therapies: rational drug combinations based on EGFR and MAPK inhibition for solid tumours and haematologic malignancies

PubMed Central

Tortora, Giampaolo; Bianco, Roberto; Daniele, Gennaro; Ciardiello, Fortunato; McCubrey, James A; Ricciardi, Maria Rosaria; Ciuffreda, Ludovica; Cognetti, Francesco; Tafuri, Agostino; Milella, Michele

2007-01-01

Accumulating evidence suggests that cancer can be envisioned as a “signaling disease”, in which alterations in the cellular genome affect the expression and/or function of oncogenes and tumour suppressor genes. This ultimately disrupts the physiologic transmission of biochemical signals that normally regulate cell growth, differentiation and programmed cell death (apoptosis). From a clinical standpoint, signal transduction inhibition as a therapeutic strategy for human malignancies has recently achieved remarkable success. However, as additional drugs move forward into the clinical arena, intrinsic and acquired resistance to “targeted” agents becomes an issue for their clinical utility. One way to overcome resistance to targeted agents is to identify genetic and epigenetic aberrations underlying sensitivity/resistance, thus enabling the selection of patients that will most likely benefit from a specific therapy. Since resistance often ensues as a result of the concomitant activation of multiple, often overlapping, signaling pathways, another possibility is to interfere with multiple, cross-talking pathways involved in growth and survival control in a rational, mechanism-based, fashion. These concepts may be usefully applied, among others, to agents that target two major signal transduction pathways: the one initiated by epidermal growth factor receptor (EGFR) signaling and the one converging on mitogen-activated protein kinase (MAPK) activation. Here we review the molecular mechanisms of sensitivity/resistance to EGFR inhibitors, as well as the rationale for combining them with other targeted agents, in an attempt to overcome resistance. In the second part of the paper, we review MAPK-targeted agents, focusing on their therapeutic potential in hematologic malignancies, and examine the prospects for combinations of MAPK inhibitors with cytotoxic agents or other signal transduction-targeted agents to obtain synergistic anti-tumour effects. PMID:17482503

Protein tyrosine kinase and mitogen-activated protein kinase signalling pathways contribute to differences in heterophil-mediated innate immune responsiveness between two lines of broilers

USDA-ARS?s Scientific Manuscript database

Protein tyrosine phosphorylation mediates signal transduction of cellular processes, with protein tyrosine kinases (PTKs) regulating virtually all signaling events. The mitogen-activated protein kinase (MAPK) super-family consists of three conserved pathways that convert receptor activation into ce...

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

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

Wang, Cheng; Nie, Xiaoke; Zhang, Yan

2015-10-15

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

Function-specific intracellular signaling pathways downstream of heparin-binding EGF-like growth factor utilized by human trophoblasts.

PubMed

Jessmon, Philip; Kilburn, Brian A; Romero, Roberto; Leach, Richard E; Armant, D Randall

2010-05-01

Heparin-binding EGF-like growth factor (HBEGF) is expressed by trophoblast cells throughout gestation. First-trimester cytotrophoblast cells are protected from hypoxia-induced apoptosis because of the accumulation of HBEGF through a posttranscriptional autocrine mechanism. Exogenous application of HBEGF is cytoprotective in a hypoxia/reoxygenation (H/R) injury model and initiates trophoblast extravillous differentiation to an invasive phenotype. The downstream signaling pathways induced by HBEGF that mediate these various cellular activities were identified using two human first-trimester cytotrophoblast cell lines, HTR-8/SVneo and SW.71, with similar results. Recombinant HBEGF (1 nM) induced transient phosphorylation of MAPK3/1 (ERK), MAPK14 (p38), and AKT within 15 min and JNK after 1-2 h. To determine which downstream pathways regulate the various functions of HBEGF, cells were treated with specific inhibitors of the ERK upstream regulator MEK (U0126), the AKT upstream regulator phosphoinositide-3 (PI3)-kinase (LY294002), MAPK14 (SB203580), and JNK (SP600125), as well as with inactive structural analogues. Only SB203580 specifically prevented HBEGF-mediated rescue during H/R, while each inhibitor attenuated HBEGF-stimulated cell migration. Accumulation of HBEGF at reduced oxygen was blocked only by a combination of U0126, SB203580, and SP600125. We conclude that HBEGF advances trophoblast extravillous differentiation through coordinate activation of PI3 kinase, ERK, MAPK14, and JNK, while only MAPK14 is required for its antiapoptotic activity. Additionally, hypoxia induces an autocrine increase in HBEGF protein levels through MAPK14, JNK or ERK. These experiments reveal a complexity of the intracellular signaling circuitry that regulates trophoblast functions critical for implantation and placentation.

Function-Specific Intracellular Signaling Pathways Downstream of Heparin-Binding EGF-Like Growth Factor Utilized by Human Trophoblasts1

PubMed Central

Jessmon, Philip; Kilburn, Brian A.; Romero, Roberto; Leach, Richard E.; Armant, D. Randall

2010-01-01

Heparin-binding EGF-like growth factor (HBEGF) is expressed by trophoblast cells throughout gestation. First-trimester cytotrophoblast cells are protected from hypoxia-induced apoptosis because of the accumulation of HBEGF through a posttranscriptional autocrine mechanism. Exogenous application of HBEGF is cytoprotective in a hypoxia/reoxygenation (H/R) injury model and initiates trophoblast extravillous differentiation to an invasive phenotype. The downstream signaling pathways induced by HBEGF that mediate these various cellular activities were identified using two human first-trimester cytotrophoblast cell lines, HTR-8/SVneo and SW.71, with similar results. Recombinant HBEGF (1 nM) induced transient phosphorylation of MAPK3/1 (ERK), MAPK14 (p38), and AKT within 15 min and JNK after 1–2 h. To determine which downstream pathways regulate the various functions of HBEGF, cells were treated with specific inhibitors of the ERK upstream regulator MEK (U0126), the AKT upstream regulator phosphoinositide-3 (PI3)-kinase (LY294002), MAPK14 (SB203580), and JNK (SP600125), as well as with inactive structural analogues. Only SB203580 specifically prevented HBEGF-mediated rescue during H/R, while each inhibitor attenuated HBEGF-stimulated cell migration. Accumulation of HBEGF at reduced oxygen was blocked only by a combination of U0126, SB203580, and SP600125. We conclude that HBEGF advances trophoblast extravillous differentiation through coordinate activation of PI3 kinase, ERK, MAPK14, and JNK, while only MAPK14 is required for its antiapoptotic activity. Additionally, hypoxia induces an autocrine increase in HBEGF protein levels through MAPK14, JNK or ERK. These experiments reveal a complexity of the intracellular signaling circuitry that regulates trophoblast functions critical for implantation and placentation. PMID:20130271

Pharmacological strategies in lung cancer-induced cachexia: effects on muscle proteolysis, autophagy, structure, and weakness.

PubMed

Chacon-Cabrera, Alba; Fermoselle, Clara; Urtreger, Alejandro J; Mateu-Jimenez, Mercè; Diament, Miriam J; de Kier Joffé, Elisa D Bal; Sandri, Marco; Barreiro, Esther

2014-11-01

Cachexia is a relevant comorbid condition of chronic diseases including cancer. Inflammation, oxidative stress, autophagy, ubiquitin-proteasome system, nuclear factor (NF)-κB, and mitogen-activated protein kinases (MAPK) are involved in the pathophysiology of cancer cachexia. Currently available treatment is limited and data demonstrating effectiveness in in vivo models are lacking. Our objectives were to explore in respiratory and limb muscles of lung cancer (LC) cachectic mice whether proteasome, NF-κB, and MAPK inhibitors improve muscle mass and function loss through several molecular mechanisms. Body and muscle weights, limb muscle force, protein degradation and the ubiquitin-proteasome system, signaling pathways, oxidative stress and inflammation, autophagy, contractile and functional proteins, myostatin and myogenin, and muscle structure were evaluated in the diaphragm and gastrocnemius of LC (LP07 adenocarcinoma) bearing cachectic mice (BALB/c), with and without concomitant treatment with NF-κB (sulfasalazine), MAPK (U0126), and proteasome (bortezomib) inhibitors. Compared to control animals, in both respiratory and limb muscles of LC cachectic mice: muscle proteolysis, ubiquitinated proteins, autophagy, myostatin, protein oxidation, FoxO-1, NF-κB and MAPK signaling pathways, and muscle abnormalities were increased, while myosin, creatine kinase, myogenin, and slow- and fast-twitch muscle fiber size were decreased. Pharmacological inhibition of NF-κB and MAPK, but not the proteasome system, induced in cancer cachectic animals, a substantial restoration of muscle mass and force through a decrease in muscle protein oxidation and catabolism, myostatin, and autophagy, together with a greater content of myogenin, and contractile and functional proteins. Attenuation of MAPK and NF-κB signaling pathway effects on muscles is beneficial in cancer-induced cachexia. © 2014 Wiley Periodicals, Inc.

Effects of cadmium on MAPK signalling pathways and HSP70 expression in a human trophoblast cell line.

PubMed

Valbonesi, P; Ricci, L; Franzellitti, S; Biondi, C; Fabbri, E

2008-08-01

The aim of this work was to provide a greater insight into the possible effects of Cd on signal transduction and stress-related pathways in reproductive tissues. Cd is a known placental toxin in both animals and humans. Our experiments were designed to study the influence of Cd on MAPK (ERK1/2, JNK1/2 and p38MAPK) activation in the extravillous trophoblast cell line, HTR-8/SVneo, used as an experimental model. We also studied the HSP70 response in cells exposed to Cd, since these proteins may have an important role in conferring protection and tolerance against teratogenic concentrations of the metal. The effects of Cd were compared with those of a well-known toxic agent, H2O2. The metal triggered MAPK activation in a dose- and time-dependent manner. At 30 microM Cd, stimulations of about 300%, 550% and 250% were observed for ERK1/2, JNK1/2, and p38MAPK, respectively. Phosphorylation of ERK1/2 and JNK1/2 was significantly induced after a 1-h exposure to 30 microM Cd, while that of p38MAPK occurred only after 8h. Similarly, H2O2 caused dose- and time-dependent activation of MAPK pathways. Cd potently stimulated HSP70 expression and that of related genes HSP70 A, B and C. H2O2 did not increase HSP70 and HSP70 A and B expression, while temporarily increasing HSP70C transcript levels. In conclusion, Cd triggers different stress responses in trophoblast cells involving HSP70 and SAPK, and also enhances ERK1/2 phosphorylation. Since MAPK dependent pathways play a crucial role during pregnancy, non-physiological activation by Cd exposure may disrupt normal functions in trophoblast cells.

Synergistic anti-tumor effect of 17AAG with the PI3K/mTOR inhibitor NVP-BEZ235 on human melanoma.

PubMed

Calero, R; Morchon, E; Martinez-Argudo, I; Serrano, R

2017-10-10

Drug resistance by MAPK signaling recovery or activation of alternative signaling pathways, such as PI3K/AKT/mTOR, is an important factor that limits the long-term efficacy of targeted therapies in melanoma patients. In the present study, we investigated the phospho-proteomic profile of RTKs and its correlation with downstream signaling pathways in human melanoma. We found that tyrosine kinase receptors expression correlated with the expression of pivotal downstream components of the RAS/RAF/MAPK and PI3K/AKT/mTOR pathways in melanoma cell lines and tumors. We also found high expression of HSP90 and the PI3K/AKT/mTOR pathway proteins, 4EBP1 and AKT compared with healthy tissue and this correlated with poor overall survival of melanoma patients. The combination of the HSP90 inhibitor 17AAG with the PI3K/mTOR inhibitor NVP-BEZ235 showed a synergistic activity decreasing melanoma cell growth, inducing apoptosis and targeting simultaneously the MAPK and PI3K/AKT/mTOR pathways. These results demonstrate that the combination of HSP90 and PI3K/mTOR inhibitors could be an effective therapeutic strategy that target the main survival pathways in melanoma and must be considered to overcome resistance to BRAF inhibitors in melanoma patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Colon cancer cells colonize the lung from established liver metastases through p38 MAPK signalling and PTHLH.

PubMed

Urosevic, Jelena; Garcia-Albéniz, Xabier; Planet, Evarist; Real, Sebastián; Céspedes, María Virtudes; Guiu, Marc; Fernandez, Esther; Bellmunt, Anna; Gawrzak, Sylwia; Pavlovic, Milica; Mangues, Ramon; Dolado, Ignacio; Barriga, Francisco M; Nadal, Cristina; Kemeny, Nancy; Batlle, Eduard; Nebreda, Angel R; Gomis, Roger R

2014-07-01

The mechanisms that allow colon cancer cells to form liver and lung metastases, and whether KRAS mutation influences where and when metastasis occurs, are unknown. We provide clinical and molecular evidence showing that different MAPK signalling pathways are implicated in this process. Whereas ERK2 activation provides colon cancer cells with the ability to seed and colonize the liver, reduced p38 MAPK signalling endows cancer cells with the ability to form lung metastasis from previously established liver lesions. Downregulation of p38 MAPK signalling results in increased expression of the cytokine PTHLH, which contributes to colon cancer cell extravasation to the lung by inducing caspase-independent death in endothelial cells of the lung microvasculature. The concerted acquisition of metastatic traits in the colon cancer cells together with the sequential colonization of liver and lung highlights the importance of metastatic lesions as a platform for further dissemination.

RAS diseases in children

PubMed Central

Niemeyer, Charlotte M.

2014-01-01

RAS genes encode a family of 21 kDa proteins that are an essential hub for a number of survival, proliferation, differentiation and senescence pathways. Signaling of the RAS-GTPases through the RAF-MEK-ERK pathway, the first identified mitogen-associated protein kinase (MAPK) cascade is essential in development. A group of genetic syndromes, named “RASopathies”, had been identified which are caused by heterozygosity for germline mutations in genes that encode protein components of the RAS/MAPK pathway. Several of these clinically overlapping disorders, including Noonan syndrome, Noonan-like CBL syndrome, Costello syndrome, cardio-facio-cutaneous (CFC) syndrome, neurofibromatosis type I, and Legius syndrome, predispose to cancer and abnormal myelopoiesis in infancy. This review focuses on juvenile myelomonocytic leukemia (JMML), a malignancy of early childhood characterized by initiating germline and/or somatic mutations in five genes of the RAS/MAPK pathway: PTPN11, CBL, NF-1, KRAS and NRAS. Natural courses of these five subtypes differ, although hematopoietic stem cell transplantation remains the only curative therapy option for most children with JMML. With whole-exome sequencing studies revealing few secondary lesions it will be crucial to better understand the RAS/MAPK signaling network with its crosstalks and feed-back loops to carefully design early clinical trials with novel pharmacological agents in this still puzzling leukemia. PMID:25420281

Mineral trioxide aggregate upregulates odonto/osteogenic capacity of bone marrow stromal cells from craniofacial bones via JNK and ERK MAPK signalling pathways.

PubMed

Wang, Y; Li, J; Song, W; Yu, J

2014-06-01

The aim of this study was to investigate effects of mineral trioxide aggregate (MTA) on odonto/osteogenic differentiation of bone marrow stromal cells (BMSCs) from craniofacial bones. Craniofacial BMSCs were isolated from rat mandible and effects of MTA on their proliferation, differentiation and MAPK pathway involvement were subsequently investigated, in vitro. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2,5-tetrazoliumbromide) assay was performed to evaluate proliferation of the MTA-treated cells. Alkaline phosphatase (ALP) activity, alizarin red staining, real-time reverse transcription polymerase chain reaction and western blot assays were used to assess differentiation capacity as well as MAPK pathway involvement. 0.02 mg/ml MTA-treated BMSCs had significantly higher ALP activity and formed more mineralized nodules than the untreated group. Odonto/osteoblastic marker genes/proteins (Alp, Runx2/RUNX2, Osx/OSX, Ocn/OCN and Dspp/DSP respectively) in MTA-treated cells were remarkably upregulated compared to untreated ones. Mechanistically, phosphorylated Jun N-terminal kinase (P-JNK) and phosphorylated extracellular regulated protein kinases (P-ERK) in MTA-treated BMSCs increased significantly in a time-dependent manner, while inhibition of JNK and ERK MAPK pathways dramatically blocked MTA-induced odonto/osteoblastic differentiation, as indicated by reduced ALP levels, weakened mineralization capacity and downregulated levels of odonto/osteoblastic marker genes (Alp, Runx2, Osx, Ocn and Dspp). Mineral trioxide aggregate promoted odonto/osteogenic capacity of craniofacial BMSCs via JNK and ERK MAPK signalling pathways. © 2014 John Wiley & Sons Ltd.

COT drives resistance to RAF inhibition through MAP kinase pathway reactivation.

PubMed

Johannessen, Cory M; Boehm, Jesse S; Kim, So Young; Thomas, Sapana R; Wardwell, Leslie; Johnson, Laura A; Emery, Caroline M; Stransky, Nicolas; Cogdill, Alexandria P; Barretina, Jordi; Caponigro, Giordano; Hieronymus, Haley; Murray, Ryan R; Salehi-Ashtiani, Kourosh; Hill, David E; Vidal, Marc; Zhao, Jean J; Yang, Xiaoping; Alkan, Ozan; Kim, Sungjoon; Harris, Jennifer L; Wilson, Christopher J; Myer, Vic E; Finan, Peter M; Root, David E; Roberts, Thomas M; Golub, Todd; Flaherty, Keith T; Dummer, Reinhard; Weber, Barbara L; Sellers, William R; Schlegel, Robert; Wargo, Jennifer A; Hahn, William C; Garraway, Levi A

2010-12-16

Oncogenic mutations in the serine/threonine kinase B-RAF (also known as BRAF) are found in 50-70% of malignant melanomas. Pre-clinical studies have demonstrated that the B-RAF(V600E) mutation predicts a dependency on the mitogen-activated protein kinase (MAPK) signalling cascade in melanoma-an observation that has been validated by the success of RAF and MEK inhibitors in clinical trials. However, clinical responses to targeted anticancer therapeutics are frequently confounded by de novo or acquired resistance. Identification of resistance mechanisms in a manner that elucidates alternative 'druggable' targets may inform effective long-term treatment strategies. Here we expressed ∼600 kinase and kinase-related open reading frames (ORFs) in parallel to interrogate resistance to a selective RAF kinase inhibitor. We identified MAP3K8 (the gene encoding COT/Tpl2) as a MAPK pathway agonist that drives resistance to RAF inhibition in B-RAF(V600E) cell lines. COT activates ERK primarily through MEK-dependent mechanisms that do not require RAF signalling. Moreover, COT expression is associated with de novo resistance in B-RAF(V600E) cultured cell lines and acquired resistance in melanoma cells and tissue obtained from relapsing patients following treatment with MEK or RAF inhibitors. We further identify combinatorial MAPK pathway inhibition or targeting of COT kinase activity as possible therapeutic strategies for reducing MAPK pathway activation in this setting. Together, these results provide new insights into resistance mechanisms involving the MAPK pathway and articulate an integrative approach through which high-throughput functional screens may inform the development of novel therapeutic strategies.

Schisandrin B elicits a glutathione antioxidant response and protects against apoptosis via the redox-sensitive ERK/Nrf2 pathway in H9c2 cells.

PubMed

Chiu, Po Yee; Chen, Na; Leong, Po Kuan; Leung, Hoi Yan; Ko, Kam Ming

2011-04-01

This study investigated the signal transduction pathway involved in the cytoprotective action of (-)schisandrin B [(-)Sch B, a stereoisomer of Sch B]. Using H9c2 cells, the authors examined the effects of (-)Sch B on MAPK and Nrf2 activation, as well as the subsequent eliciting of glutathione response and protection against apoptosis. Pharmacological tools, such as cytochrome P-450 (CYP) inhibitor, antioxidant, MAPK inhibitor, and Nrf2 RNAi, were used to delineate the signaling pathway. (-)Sch B caused a time-dependent activation of MAPK in H9c2 cells, with the degree of ERK activation being much larger than that of p38 or JNK. The MAPK activation was followed by an increase in the level of nuclear Nrf2, an indirect measure of Nrf2 activation, and the eliciting of a glutathione antioxidant response. The activation of MAPK and Nrf2 seemed to involve oxidants generated from a CYP-catalyzed reaction with (-)Sch B. Both ERK inhibition by U0126 and Nrf2 suppression by Nrf2 RNAi transfection largely abolished the cytoprotection against hypoxia/reoxygenation-induced apoptosis in (-)Sch B-pretreated cells. (-)Sch B pretreatment potentiated the reoxygenation-induced ERK activation, whereas both p38 and JNK activations were suppressed. Under the condition of ERK inhibition, Sch B treatment did not protect against ischemia/reperfusion injury in an ex vivo rat heart model. The results indicate that (-)Sch B triggers a redox-sensitive ERK/Nrf2 signaling, which then elicits a cellular glutathione antioxidant response and protects against hypoxia/reoxygenation-induced apoptosis in H9c2 cells. The ERK-mediated signaling is also likely involved in the cardioprotection afforded by Sch B in vivo.

Qingfei Xiaoyan Wan, a traditional Chinese medicine formula, ameliorates Pseudomonas aeruginosa–induced acute lung inflammation by regulation of PI3K/AKT and Ras/MAPK pathways

PubMed Central

Hou, Yuanyuan; Nie, Yan; Cheng, Binfeng; Tao, Jin; Ma, Xiaoyao; Jiang, Min; Gao, Jie; Bai, Gang

2016-01-01

Gram-negative pathogen–induced nosocomial infections and resistance are a most serious menace to global public health. Qingfei Xiaoyan Wan (QF), a traditional Chinese medicine (TCM) formula, has been used clinically in China for the treatment of upper respiratory tract infections, acute or chronic bronchitis and pulmonary infection. In this study, the effects of QF on Pseudomonas aeruginosa–induced acute pneumonia in mice were evaluated. The mechanisms by which four typical anti-inflammatory ingredients from QF, arctigenin (ATG), cholic acid (CLA), chlorogenic acid (CGA) and sinapic acid (SPA), regulate anti-inflammatory signaling pathways and related targets were investigated using molecular biology and molecular docking techniques. The results showed that pretreatment with QF significantly inhibits the release of cytokines (TNF-α and IL-6) and chemokines (IL-8 and RANTES), reduces leukocytes recruitment into inflamed tissues and ameliorates pulmonary edema and necrosis. In addition, ATG was identified as the primary anti-inflammatory agent with action on the PI3K/AKT and Ras/MAPK pathways. CLA and CGA enhanced the actions of ATG and exhibited synergistic NF-κB inactivation effects possibly via the Ras/MAPK signaling pathway. Moreover, CLA is speculated to target FGFR and MEK firstly. Overall, QF regulated the PI3K/AKT and Ras/MAPK pathways to inhibit pathogenic bacterial infections effectively. PMID:27175332

Nitric oxide balances osteoblast and adipocyte lineage differentiation via the JNK/MAPK signaling pathway in periodontal ligament stem cells.

PubMed

Yang, Shan; Guo, Lijia; Su, Yingying; Wen, Jing; Du, Juan; Li, Xiaoyan; Liu, Yitong; Feng, Jie; Xie, Yongmei; Bai, Yuxing; Wang, Hao; Liu, Yi

2018-05-02

Critical tissues that undergo regeneration in periodontal tissue are of mesenchymal origin; thus, investigating the regulatory mechanisms underlying the fate of periodontal ligament stem cells could be beneficial for application in periodontal tissue regeneration. Nitric oxide (NO) regulates many biological processes in developing embryos and adult stem cells. The present study was designed to investigate the effects of NO on the function of human periodontal ligament stem cells (PDLSCs) as well as to elucidate the underlying molecular mechanisms. Immunofluorescent staining and flow cytometry were used for stem cell identification. Western blot, reverse transcription polymerase chain reaction (RT-PCR), immunofluorescent staining, and flow cytometry were used to examine the expression of NO-synthesizing enzymes. The proliferative capacity of PDLSCs was determined by EdU assays. The osteogenic potential of PDLSCs was tested using alkaline phosphatase (ALP) staining, Alizarin Red staining, and calcium concentration detection. Oil Red O staining was used to analyze the adipogenic ability. Western blot, RT-PCR, and staining were used to examine the signaling pathway. Human PDLSCs expressed both inducible NO synthase (iNOS) and endothelial NO synthase (eNOS) and produced NO. Blocking the generation of NO with the NOS inhibitor L-N G -monomethyl arginine (L-NMMA) had no influence on PDLSC proliferation and apoptosis but significantly attenuated the osteogenic differentiation capacity and stimulated the adipogenic differentiation capacity of PDLSCs. Increasing the physiological level of NO with NO donor sodium nitroprusside (SNP) significantly promoted the osteogenic differentiation capacity but reduced the adipogenic differentiation capacity of PDLSCs. NO balances the osteoblast and adipocyte lineage differentiation in periodontal ligament stem cells via the c-Jun N-terminal kinase (JNK)/mitogen-activated protein kinase (MAPK) signaling pathway. NO is essential for maintaining the balance between osteoblasts and adipocytes in PDLSCs via the JNK/MAPK signaling pathway. NO balances osteoblast and adipocyte lineage differentiation via JNK/MAPK signaling pathway.

Low-dose occupational exposure to benzene and signal transduction pathways involved in the regulation of cellular response to oxidative stress.

PubMed

Fenga, Concettina; Gangemi, Silvia; Giambò, Federica; Tsitsimpikou, Christina; Golokhvast, Kirill; Tsatsakis, Aristidis; Costa, Chiara

2016-02-15

Benzene metabolism seems to modulate NF-κB, p38-MAPK (mitogen-activated protein kinase) and signal transducer and activator of transcription 3 (STAT3) signalling pathways via the production of reactive oxygen species. This study aims to evaluate the effects of low-dose, long-term exposure on NF-κB, STAT3, p38-MAPK and stress-activated protein kinase/Jun amino-terminal kinase (SAPK/JNK) signal transduction pathways in peripheral blood mononuclear cells in gasoline station attendants. The influence of consumption of vegetables and fruits on these pathways has also been evaluated. A total of 91 men, employed in gasoline stations located in eastern Sicily, were enrolled for this study and compared with a control group of 63 male office workers with no history of exposure to benzene. The exposure was assessed by measuring urinary trans,trans-muconic acid (t,t-MA) concentration. Quantitative analyses were performed for proteins NF-κB p65, phospho-NF-κB p65, phospho-IκB-α, phospho-SAPK/JNK, phospho-p38 MAPK and phospho-STAT3 using an immunoenzymatic assay. The results of this study indicate significantly higher t,t-MA levels in gasoline station attendants. With regard to NF-κB, phospho-IκB-α and phospho-STAT3 proteins, statistically significant differences were observed in workers exposed to benzene. However, no differences were observed in SAPK/JNK and p38-MAPK activation. These changes were positively correlated with t,t-MA levels, but only phospho-NF-κB p65 was associated with the intake of food rich in antioxidant active principles. Chronic exposure to low-dose benzene can modulate signal transduction pathways activated by oxidative stress and involved in cell proliferation and apoptosis. This could represent a possible mechanism of carcinogenic action of chronic benzene exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

Inhibition of the protein kinase MK-2 protects podocytes from nephrotic syndrome-related injury

PubMed Central

Pengal, Ruma; Guess, Adam J.; Agrawal, Shipra; Manley, Joshua; Ransom, Richard F.; Mourey, Robert J.; Smoyer, William E.

2011-01-01

While mitogen-activated protein kinase (MAPK) activation has been implicated in the pathogenesis of various glomerular diseases, including nephrotic syndrome (NS), its specific role in podocyte injury is not known. We hypothesized that MK-2, a downstream substrate of p38 MAPK, mediates the adverse effects of this pathway and that inhibition of MK-2 would protect podocytes from NS-related injury. Using cultured podocytes, we analyzed 1) the roles of MK-2 and p38 MAPK in puromycin aminonucleoside (PAN)-induced podocyte injury; 2) the ability of specific MK-2 and p38 MAPK inhibitors to protect podocytes against injury; 3) the role of serum albumin, known to induce podocyte injury, in activating p38 MAPK/MK-2 signaling; and 4) the role of p38 MAPK/MK-2 signaling in the expression of Cox-2, an enzyme associated with podocyte injury. Treatment with protein kinase inhibitors specific for both MK-2 (C23, a pyrrolopyridine-type compound) or p38 MAPK (SB203580) reduced PAN-induced podocyte injury and actin cytoskeletal disruption. Both inhibitors reduced baseline podocyte p38 MAPK/MK-2 signaling, as measured by the degree of phosphorylation of HSPB1, a downstream substrate of MK-2, but exhibited disparate effects on upstream signaling. Serum albumin activated p38 MAPK/MK-2 signaling and induced Cox-2 expression, and these responses were blocked by both inhibitors. Given the critical importance of podocyte injury to both NS and other progressive glomerular diseases, these data suggest an important role for p38 MAPK/MK-2 signaling in podocyte injury and identify MK-2 inhibition as a promising potential therapeutic strategy to protect podocytes in various glomerular diseases. PMID:21613416

Cigarette smoke exposure reveals a novel role for the MEK/ERK1/2 MAPK pathway in regulation of CFTR

PubMed Central

Xu, Xiaohua; Balsiger, Robert; Tyrrell, Jean; Boyaka, Prosper N.; Tarran, Robert; Cormet-Boyaka, Estelle

2015-01-01

Background CFTR plays a key role in maintenance of lung fluid homeostasis. Cigarette smoke decreases CFTR expression in the lung but neither the mechanisms leading to CFTR loss, nor potential ways to prevent its loss have been identified to date. Methods The molecular mechanisms leading to down-regulation of CFTR by cigarette smoke were determined using pharmacologic inhibitors and silencing RNAs. Results Using human bronchial epithelial cells, here we show that cigarette smoke induces degradation of CFTR that is attenuated by the lysosomal inhibitors, but not proteasome inhibitors. Cigarette smoke can activate multiple signaling pathways in airway epithelial cells, including the MEK/Erk1/2 MAPK pathway regulating cell survival. Interestingly, pharmacological inhibition of the MEK/Erk1/2 MAPK pathway prevented the loss of plasma membrane CFTR upon cigarette smoke exposure. Similarly, decreased expression of Erk1/2 using silencing RNAs prevented the suppression of CFTR protein by cigarette smoke. Conversely, specific inhibitors of the JNK or p38 MAPK pathways had no effect on CFTR decrease after cigarette smoke exposure. In addition, inhibition of the MEK/Erk1/2 MAPK pathway prevented the reduction of the airway surface liquid observed upon cigarette smoke exposure of primary human airway epithelial cells. Finally, addition of the antioxidant NAC inhibited activation of Erk1/2 by cigarette smoke and precluded the cigarette smoke-induced decrease of CFTR. Conclusions These results show that the MEK/Erk1/2 MAPK pathway regulates plasma membrane CFTR in human airway cells. General Significance The MEK/Erk1/2 MAPK pathway should be considered as a target for strategies to maintain/restore CFTR expression in the lung of smokers. PMID:25697727

Mitogen activated protein kinase (MAPK) pathway regulates heme oxygenase-1 gene expression by hypoxia in vascular cells.

PubMed

Ryter, Stefan W; Xi, Sichuan; Hartsfield, Cynthia L; Choi, Augustine M K

2002-08-01

Hypoxia induces the stress protein heme oxygenase-1 (HO-1), which participates in cellular adaptation. The molecular pathways that regulate ho-1 gene expression under hypoxia may involve mitogen activated protein kinase (MAPK) signaling and reactive oxygen. Hypoxia (8 h) increased HO-1 mRNA in rat pulmonary aortic endothelial cells (PAEC), and also activated both extracellular signal-regulated kinase 1 (ERK1)/ERK2 and p38 MAPK pathways. The role of these kinases in hypoxia-induced ho-1 gene expression was examined using chemical inhibitors of these pathways. Surprisingly, SB203580, an inhibitor of p38 MAPK, and PD98059, an inhibitor of mitogen-activated protein kinase kinase (MEK1), strongly enhanced hypoxia-induced HO-1 mRNA expression in PAEC. UO126, a MEK1/2 inhibitor, enhanced HO-1 expression in PAEC under normoxia, but not hypoxia. Diphenylene iodonium, an inhibitor of NADPH oxidase, also induced the expression of HO-1 in PAEC under both normoxia and hypoxia. Similar results were observed in aortic vascular smooth muscle cells. Furthermore, hypoxia induced activator protein (AP-1) DNA-binding activity in PAEC. Pretreatment with SB203580 and PD98059 enhanced AP-1 binding activity under hypoxia in PAEC; UO126 stimulated AP-1 binding under normoxia, whereas diphenylene iodonium stimulated AP-1 binding under normoxia and hypoxia. These results suggest a relationship between MAPK and hypoxic regulation of ho-1 in vascular cells, involving AP-1.

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

PubMed Central

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

2012-01-01

Pleiotropic effects of leptin have been identified in reproduction and pregnancy, particularly in the placenta, where it works as an autocrine hormone. In this work, we demonstrated that human chorionic gonadotropin (hCG) added to JEG-3 cell line or to placental explants induces endogenous leptin expression. We also found that hCG increased cAMP intracellular levels in BeWo cells in a dose-dependent manner, stimulated cAMP response element (CRE) activity and the cotransfection with an expression plasmid of a dominant negative mutant of CREB caused a significant inhibition of hCG stimulation of leptin promoter activity. These results demonstrate that hCG indeed activates cAMP/PKA pathway, and that this pathway is involved in leptin expression. Nevertheless, we found leptin induction by hCG is dependent on cAMP levels. Treatment with (Bu)2cAMP in combination with low and non stimulatory hCG concentrations led to an increase in leptin expression, whereas stimulatory concentrations showed the opposite effect. We found that specific PKA inhibition by H89 caused a significant increase of hCG leptin induction, suggesting that probably high cAMP levels might inhibit hCG effect. It was found that hCG enhancement of leptin mRNA expression involved the MAPK pathway. In this work, we demonstrated that hCG leptin induction through the MAPK signaling pathway is inhibited by PKA. We observed that ERK1/2 phosphorylation increased when hCG treatment was combined with H89. In view of these results, the involvement of the alternative cAMP/Epac signaling pathway was studied. We observed that a cAMP analogue that specifically activates Epac (CPT-OMe) stimulated leptin expression by hCG. In addition, the overexpression of Epac and Rap1 proteins increased leptin promoter activity and enhanced hCG. In conclusion, we provide evidence suggesting that hCG induction of leptin gene expression in placenta is mediated not only by activation of the MAPK signaling pathway but also by the alternative cAMP/Epac signaling pathway. PMID:23056265

Sulfur dioxide inhibits vascular smooth muscle cell proliferation via suppressing the Erk/MAP kinase pathway mediated by cAMP/PKA signaling

PubMed Central

Liu, D; Huang, Y; Bu, D; Liu, A D; Holmberg, L; Jia, Y; Tang, C; Du, J; Jin, H

2014-01-01

The present study was designed to investigate the role of endogenous sulfur dioxide (SO2) in vascular smooth muscle cell (VSMC) proliferation, and explore the possible role of cross-talk between cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) and extracellular signal-regulated kinase (Erk)/mitogen-activated protein kinase (MAPK) pathways in this action. By cell counting, growth curve depict, flow cytometry and bromodeoxyuridine (BrdU) labeling assays, we found that SO2 inhibited VSMC proliferation by preventing cell cycle progression from G1 to S phase and by reducing DNA synthesis. SO2 synthase aspartate aminotransferase (AAT1 and AAT2) overexpression significantly inhibited serum-induced proliferating cell nuclear antigen (PCNA) protein expression in VSMCs, demonstrated by western blot analysis. Moreover, overexpression of AAT1 or AAT2 markedly reduced incorporation of BrdU in serum-treated VSMCs. By contrast, either AAT1 or AAT2 knockdown significantly exacerbated serum-stimulated VSMC proliferation. Thus, both exogenous- and endogenous-derived SO2 suppressed serum-induced VSMC proliferation. However, annexin V-propidium iodide (PI) staining and cell cycle analysis demonstrated that SO2 did not influence VSMC apoptosis in the serum-induced proliferation model. In a platelet-derived growth factor (PDGF)-BB-stimulated VSMC proliferation model, SO2 dephosphorylated the active sites of Erk1/2, MAPK kinase 1/2 and RAF proto-oncogene serine/threonine-protein kinase (c-Raf) induced by PDGF-BB. However, the inactivation of the three kinases of the Erk/MAPK pathway was not due to the separate interferences on them by SO2 simultaneously, but a consequence of the influence on the upstream activity of the c-Raf molecule. Hence, we examined the cAMP/PKA pathway, which could inhibit Erk/MAPK transduction in VSMCs. The results showed that SO2 could stimulate the cAMP/PKA pathway to block c-Raf activation, whereas the Ser259 site on c-Raf had an important role in SO2-induced suppression of Erk/MAPK pathway. The present study firstly demonstrated that SO2 exerted a negative regulation of VSMC proliferation via suppressing the Erk/MAPK pathway mediated by cAMP/PKA signaling. PMID:24853429

Molecular analysis of pediatric brain tumors identifies microRNAs in pilocytic astrocytomas that target the MAPK and NF-κB pathways.

PubMed

Jones, Tania A; Jeyapalan, Jennie N; Forshew, Tim; Tatevossian, Ruth G; Lawson, Andrew R J; Patel, Sheena N; Doctor, Gabriel T; Mumin, Muhammad A; Picker, Simon R; Phipps, Kim P; Michalski, Antony; Jacques, Thomas S; Sheer, Denise

2015-12-18

Pilocytic astrocytomas are slow-growing tumors that usually occur in the cerebellum or in the midline along the hypothalamic/optic pathways. The most common genetic alterations in pilocytic astrocytomas activate the ERK/MAPK signal transduction pathway, which is a major driver of proliferation but is also believed to induce senescence in these tumors. Here, we have conducted a detailed investigation of microRNA and gene expression, together with pathway analysis, to improve our understanding of the regulatory mechanisms in pilocytic astrocytomas. Pilocytic astrocytomas were found to have distinctive microRNA and gene expression profiles compared to normal brain tissue and a selection of other pediatric brain tumors. Several microRNAs found to be up-regulated in pilocytic astrocytomas are predicted to target the ERK/MAPK and NF-κB signaling pathways as well as genes involved in senescence-associated inflammation and cell cycle control. Furthermore, IGFBP7 and CEBPB, which are transcriptional inducers of the senescence-associated secretory phenotype (SASP), were also up-regulated together with the markers of senescence and inflammation, CDKN1A (p21), CDKN2A (p16) and IL1B. These findings provide further evidence of a senescent phenotype in pilocytic astrocytomas. In addition, they suggest that the ERK/MAPK pathway, which is considered the major driver of these tumors, is regulated not only by genetic aberrations but also by microRNAs.

[MAP kinases--molecular transistors in animals and plants].

PubMed

Petersen, Morten; Brodersen, Peter; Mundy, John

2002-06-10

The survival of multicellular organisms depends on the ability of their cells to communicate with each other and to respond to environmental changes. A goal of modern biology is to uncover the processes by which these cellular signals are transduced. Recent studies have shown that MAP-kinases (MAPKs) are important constituents of such signal transduction pathways. MAPKs function as modules in phosphorelay cascades to activate or repress the activity of downstream target proteins. For example, recent research with knockout mice has shown that mammalian MAPKs are involved in the control of neuronal apoptosis and the activation of immune responses. These mammalian MAPKs exert their control by both promoting and inhibiting specific processes. Surprisingly, plants also use MAPKs to control their immune responses, and plant MAPKs also seem to play dual roles as positive and negative regulators. Such mechanistic similarities provide the basis for fruitful conceptual exchange between molecular research on animals and plants.

JAK2-V617F-induced MAPK activity is regulated by PI3K and acts synergistically with PI3K on the proliferation of JAK2-V617F-positive cells

PubMed Central

Wolf, Alexandra; Eulenfeld, René; Gäbler, Karoline; Rolvering, Catherine; Haan, Serge; Behrmann, Iris; Denecke, Bernd; Haan, Claude; Schaper, Fred

2013-01-01

The identification of a constitutively active JAK2 mutant, namely JAK2-V617F, was a milestone in the understanding of Philadelphia chromosome-negative myeloproliferative neoplasms. The JAK2-V617F mutation confers cytokine hypersensitivity, constitutive activation of the JAK-STAT pathway, and cytokine-independent growth. In this study we investigated the mechanism of JAK2-V617F-dependent signaling with a special focus on the activation of the MAPK pathway. We observed JAK2-V617F-dependent deregulated activation of the multi-site docking protein Gab1 as indicated by constitutive, PI3K-dependent membrane localization and tyrosine phosphorylation of Gab1. Furthermore, we demonstrate that PI3K signaling regulates MAPK activation in JAK2-V617F-positve cells. This cross-regulation of the MAPK pathway by PI3K affects JAK2-V617F-specific target gene induction, erythroid colony formation, and regulates proliferation of JAK2-V617F-positive patient cells in a synergistically manner. PMID:24069558

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

PubMed

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

2007-01-04

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

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

PubMed Central

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

2007-01-01

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

The calcineurin pathway links hyperpolarization (Kir2.1)-induced Ca2+ signals to human myoblast differentiation and fusion.

PubMed

Konig, Stéphane; Béguet, Anne; Bader, Charles R; Bernheim, Laurent

2006-08-01

In human myoblasts triggered to differentiate, a hyperpolarization, resulting from K+ channel (Kir2.1) activation, allows the generation of an intracellular Ca2+ signal. This signal induces an increase in expression/activity of two key transcription factors of the differentiation process, myogenin and MEF2. Blocking hyperpolarization inhibits myoblast differentiation. The link between hyperpolarization-induced Ca2+ signals and the four main regulatory pathways involved in myoblast differentiation was the object of this study. Of the calcineurin, p38-MAPK, PI3K and CaMK pathways, only the calcineurin pathway was inhibited when Kir2.1-linked hyperpolarization was blocked. The CaMK pathway, although Ca2+ dependent, is unaffected by changes in membrane potential or block of Kir2.1 channels. Concerning the p38-MAPK and PI3K pathways, their activity is present already in proliferating myoblasts and they are unaffected by hyperpolarization or Kir2.1 channel block. We conclude that the Kir2.1-induced hyperpolarization triggers human myoblast differentiation via the activation of the calcineurin pathway, which, in turn, induces expression/activity of myogenin and MEF2.

Somatic ACE regulates self-renewal of mouse spermatogonial stem cells via the MAPK signaling pathway.

PubMed

Gao, Tingting; Zhao, Xin; Liu, Chenchen; Shao, Binbin; Zhang, Xi; Li, Kai; Cai, Jinyang; Wang, Su; Huang, Xiaoyan

2018-05-24

Spermatogonial stem cell (SSC) self-renewal is an indispensable part of spermatogenesis. Angiotensin I-converting enzyme (ACE) is a zinc dipeptidyl carboxypeptidase that plays a critical role in regulation of the renin-angiotensin system. Here, we used RT-PCR and Western blot analysis to confirm that somatic ACE (sACE) but not testicular ACE (tACE) is highly expressed in mouse testis before postpartum day 7 and in cultured SSCs. Our results revealed that sACE is located on the membrane of SSCs. Treating cultured SSCs with the ACE competitive inhibitor captopril was found to inhibit sACE activity, and significantly reduced the proliferation rate of SSCs. Microarray analysis identified 651 genes with significant differential expression. KEGG pathway analysis showed that these differentially expressed genes are mainly involved in the mitogen-activated protein kinase (MAPK) signaling pathway and cell cycle. sACE was found to play an important role in SSC self-renewal via the regulation of MAPK-dependent cell proliferation.

ET-1 Promotes Differentiation of Periodontal Ligament Stem Cells into Osteoblasts through ETR, MAPK, and Wnt/β-Catenin Signaling Pathways under Inflammatory Microenvironment

PubMed Central

Liang, Li; Zhou, Wei; Yang, Nan; Yu, Jifeng; Liu, Hongchen

2016-01-01

Periodontitis is a kind of chronic inflammatory disease that affects the tooth-supporting tissues. ET-1 is related to periodontitis and involved in the regulation of cytokines, but the mechanisms remain unclear. The aim of this study is to investigate how ET-1 affects proinflammatory cytokine expression and differentiation in human periodontal ligament stem cells (PDLSCs). PDLSCs were isolated from the periodontal ligament tissues of periodontitis patients and then treated with ET-1 (1, 10, or 100 nM) for 12 h, 24 h, or 72 h. The osteogenic potential of PDLSCs was tested using ALP staining. TNF-α, IL-1β, and IL-6 levels were evaluated by ELISA and western blot. Runx2, OCN, and COL1 mRNA and western levels were detected by RT-PCR and western blot, respectively. To examine the signaling pathways and molecular mechanisms involved in ET-1-mediated cytokine expression and osteogenic differentiation, ETR pathway, MAPKs pathway, Wnt/β-catenin pathway, and Wnt/Ca2+ pathway were detected by RT-PCR and western blot, respectively. ET-1 promoted differentiation of PDLSCs into osteoblasts by increasing secretion of TNF-α, IL-1β, and IL-6 in a dose- and time-dependent manner. ET-1 also increased expression of Runx2, OCN, and COL1. ET-1 promotes differentiation of PDLSCs into osteoblasts through ETR, MAPK, and Wnt/β-catenin signaling pathways under inflammatory microenvironment. PMID:26884650

Distinct effects of thrombopoietin depending on a threshold level of activated Mpl in BaF-3 cells.

PubMed

Millot, Gaël A; Vainchenker, William; Duménil, Dominique; Svinarchuk, Fédor

2002-06-01

Thrombopoietin (TPO) plays a critical role in megakaryopoiesis through binding to its receptor Mpl. This involves activation of various intracellular signaling pathways, including phosphoinositide 3-kinase (PI3K) and the mitogen-activated protein kinase (MAPK) pathways. Their precise role in TPO-mediated proliferation, survival and differentiation is not fully understood. In the present study, we show that TPO induces different biological responses in Mpl-transduced BaF-3 cells, depending on the cell surface density of Mpl and the resulting activation level of signaling pathways. TPO mediates cell proliferation in cells expressing high levels of Mpl but only mediates survival without proliferation in cells expressing low levels of the receptor. By using the kinase inhibitors PD98059 and LY294002, we further showed that the activation level of the PI3K and MAPK p42/44 pathways is a determining factor for the proliferative effect. In cells expressing low levels of Mpl, the survival effect was strongly dependent on the activation level of the PI3K/AKT, but not the MAPK p42/44 pathway. Moreover, this effect was correlated with the phosphorylation level of BAD but not with the expression level of Bcl-X(L). However, PI3K pathway inhibition did not increase apoptosis when BaF-3 cells proliferated in response to TPO, indicating a compensating mechanism from other Mpl signaling pathways in this case.

PKI-587 and sorafenib targeting PI3K/AKT/mTOR and Ras/Raf/MAPK pathways synergistically inhibit HCC cell proliferation.

PubMed

Gedaly, Roberto; Angulo, Paul; Hundley, Jonathan; Daily, Michael F; Chen, Changguo; Evers, B Mark

2012-08-01

Deregulated Ras/Raf/MAPK and PI3K/AKT/mTOR signaling pathways are found in hepatocellular carcinoma (HCC). This study aimed to test the inhibitory effects of PKI-587 and sorafenib as single agents or in combination on HCC (Huh7 cell line) proliferation. (3)H-thymidine incorporation and MTT assay were used to assess Huh7 cell proliferation. Phosphorylation of the key enzymes in the Ras/Raf/MAPK and PI3K/AKT/mTOR pathways was detected by Western blot. We found that PKI-587 is a more potent PI3K/mTOR inhibitor than PI-103. Combination of PKI-587 and sorafenib was a more effective inhibitor of Huh7 proliferation than the combination of PI-103 and sorafenib. Combination of PKI-587 and sorafenib synergistically inhibited epidermal growth factor (EGF)-stimulated Huh7 proliferation compared with monodrug therapy. EGF increased phosphorylation of Ras/Raf downstream signaling proteins MEK and ERK; EGF-stimulated activation was inhibited by sorafenib. However, sorafenib, as a single agent, increased AKT (Ser473) phosphorylation. EGF-stimulated AKT (ser473) activation was inhibited by PKI-587. PKI-587 is a potent inhibitor of AKT (Ser473), mTOR (Ser2448), and S6K (Thr389) phosphorylation; in contrast, rapamycin stimulated mTOR complex 2 substrate AKT(Ser473) phosphorylation although it inhibited mTOR complex 1 substrate S6K phosphorylation. PKI-587, as a single agent, stimulated MEK and ERK phosphorylation. However, when PKI-587 and sorafenib were used in combination, they inhibited all the tested kinases in the Ras/Raf /MAPK and PI3K/AKT/mTOR pathways. The combination of PKI-587 and sorafenib has the advantage over monodrug therapy on inhibition of HCC cell proliferation by blocking both PI3K/AKT/mTOR and Ras/Raf/MAPK signaling pathways. Copyright © 2012 Elsevier Inc. All rights reserved.

The Role of the Neurofibromin-Syndecan-CASK Complex in the Regulation of Synaptic Ras-MAPK Signaling and Dendritic Spine Plasticity

DTIC Science & Technology

2006-02-01

Morgan, K., Hasz, D. E., Mao, Z., and Largaespada, D. A. (2005). Nf1 gene inactivation in acute myeloid leukemia cells confers cytarabine resistance through MAPK and mTOR pathways. Leukemia. VII. Appendices: None

Strategies of biochemical adaptation for hibernation in a South American marsupial Dromiciops gliroides: 1. Mitogen-activated protein kinases and the cell stress response.

PubMed

Wijenayake, Sanoji; Luu, Bryan E; Zhang, Jing; Tessier, Shannon N; Quintero-Galvis, Julian F; Gaitán-Espitia, Juan Diego; Nespolo, Roberto F; Storey, Kenneth B

2017-12-14

Hibernation is a period of torpor and heterothermy that is typically associated with a strong reduction in metabolic rate, global suppression of transcription and translation, and upregulation of various genes/proteins that are central to the cellular stress response such as protein kinases, antioxidants, and heat shock proteins. The current study examined cell signaling cascades in hibernating monito del monte, Dromiciops gliroides, a South American marsupial of the Order Microbiotheria. Responses to hibernation by members of the mitogen-activated protein kinase (MAPK) pathways, and their roles in coordinating hibernator metabolism were examined in liver, kidney, heart and brain of control and versus hibernating (4days continuous torpor) D. gliroides. The targets evaluated included key protein kinases in their activated phosphorylated forms (p-ERK/MAPK 1/2, p-MEK1, p-MSK1, p-p38, p-JNK) and related target proteins (p-CREB 2, p-ATF2, p-c-Jun and p-p53). Liver exhibited a strong coordinated response by MAPK members to hibernation with significant increases in protein phosphorylation levels of p-MEK1, p-ERK/MAPK1/2, p-MSK1, p-JNK and target proteins c-Jun, and p-ATF2, all combining to signify a strong activation of MAPK signaling during hibernation. Kidney also showed activation of MAPK cascades with significant increases in p-MEK1, p-ERK/MAPK1/2, p-p38, and p-c-Jun levels in hibernating animals. By contrast, responses by heart and brain indicated reduced MAPK pathway function during torpor with reduced phosphorylation of targets including p-ERK/MAPK 1/2 in both tissues as well as lower p-p38 and p-JNK content in heart. Overall, the data indicate a vital role for MAPK signaling in regulating the cell stress response during marsupial hibernation. Copyright © 2017 Elsevier Inc. All rights reserved.

Human melanoma cells resistant to MAPK inhibitors can be effectively targeted by inhibition of the p90 ribosomal S6 kinase

PubMed Central

Kosnopfel, Corinna; Sinnberg, Tobias; Sauer, Birgit; Niessner, Heike; Schmitt, Anja; Makino, Elena; Forschner, Andrea; Hailfinger, Stephan; Garbe, Claus; Schittek, Birgit

2017-01-01

The clinical availability of small molecule inhibitors specifically targeting mutated BRAF marked a significant breakthrough in melanoma therapy. Despite a dramatic anti-tumour activity and improved patient survival, rapidly emerging resistance, however, greatly limits the clinical benefit. The majority of the already described resistance mechanisms involve a reactivation of the MAPK signalling pathway. The p90 ribosomal S6 kinase (RSK), a downstream effector of the MAPK signalling cascade, has been reported to enhance survival of melanoma cells in response to chemotherapy. Here, we can show that RSK activity is significantly increased in human melanoma cells with acquired resistance to the BRAFV600E/K inhibitor vemurafenib. Interestingly, inhibition of RSK signalling markedly impairs the viability of vemurafenib resistant melanoma cells and is effective both in two-dimensional and in three-dimensional culture systems, especially in a chronic, long-term application. The effect of RSK inhibition can be partly replicated by downregulation of the well-known RSK target, Y-box binding protein 1 (YB-1). Intriguingly, RSK inhibition also retains its efficacy in melanoma cells with combined resistance to vemurafenib and the MEK inhibitor trametinib. These data suggest that active RSK signalling might be an attractive novel therapeutic target in melanoma with acquired resistance to MAPK pathway inhibitors. PMID:28415756

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.

Mitogen-activated protein kinase inhibition reduces mucin 2 production and mucinous tumor growth.

PubMed

Dilly, Ashok K; Song, Xinxin; Zeh, Herbert J; Guo, Zong S; Lee, Yong J; Bartlett, David L; Choudry, Haroon A

2015-10-01

Excessive accumulation of mucin 2 (MUC2) protein (a gel-forming secreted mucin) within the peritoneal cavity is the major cause of morbidity and mortality in pseudomyxoma peritonei (PMP), a unique mucinous malignancy of the appendix. Mitogen-activated protein kinase (MAPK) signaling pathway is upregulated in PMP and has been shown to modulate MUC2 promoter activity. We hypothesized that targeted inhibition of the MAPK pathway would be a novel, effective, and safe therapeutic strategy to reduce MUC2 production and mucinous tumor growth. We tested RDEA119, a specific MEK1/2 (MAPK extracellular signal-regulated kinase [ERK] kinase) inhibitor, in MUC2-secreting LS174T cells, human PMP explant tissue, and in a unique intraperitoneal murine xenograft model of PMP. RDEA119 reduced ERK1/2 phosphorylation and inhibited MUC2 messenger RNA and protein expression in vitro. In the xenograft model, chronic oral therapy with RDEA119 inhibited mucinous tumor growth in an MAPK pathway-dependent manner and this translated into a significant improvement in survival. RDEA119 downregulated phosphorylated ERK1/2 and nuclear factor κB p65 protein signaling and reduced activating protein 1 (AP1) transcription factor binding to the MUC2 promoter in LS174T cells. This study provides a preclinical rationale for the use of MEK inhibitors to treat patients with PMP. Copyright © 2015 Elsevier Inc. All rights reserved.

HMGB1-TLR4 Axis Plays a Regulatory Role in the Pathogenesis of Mesial Temporal Lobe Epilepsy in Immature Rat Model and Children via the p38MAPK Signaling Pathway.

PubMed

Yang, Weihong; Li, Jing; Shang, Yun; Zhao, Li; Wang, Mingying; Shi, Jipeng; Li, Shujun

2017-04-01

The HMGB1-TLR4 axis is activated in adult mouse models of acute and chronic seizure. Nevertheless, whether HMGB1 was involved in the pathogenesis of mesial temporal lobe epilepsy (MTLE) remains unknown. In this study, we first measured the dynamic expression patterns of HMGB1 and TLR4 in the hippocampi of a rat model and in children with MTLE, as well as the levels of TNF-α and IL-1β. In addition, HMGB1 was added to mimic the process of inflammatory response in neurons. Neuronal somatic size and dendritic length were measured by immunohistochemistry and digital imaging. The results showed that the expression of HMGB1 and TLR4 as well as the levels of TNF-α and IL-1β were higher in the three stages of MTLE development in the rat model and in the children with MTLE. HMGB1 increased the levels of TNF-α and IL-1β, upregulated the protein level of p-p38MAPK and promoted the growth of cell somatic size and dendritic length in neurons. Pre-treatment with p38MAPK inhibitor SB203580 decreased the levels of TNF-α and IL-1β, while downregulation of TLR4 significantly reduced HMGB1-induced p38MAPK signaling pathway activation. These data demonstrated that the HMGB1-TLR4 axis may play an important role in the pathogenesis of MTLE via the p38MAPK signaling pathway.

The protective effect of Rhizoma Dioscoreae extract against alveolar bone loss in ovariectomized rats via regulating Wnt and p38 MAPK signaling.

PubMed

Zhang, Zhiguo; Xiang, Lihua; Bai, Dong; Wang, Wenlai; Li, Yan; Pan, Jinghua; Liu, Hong; Wang, Shaojun; Xiao, Gary Guishan; Ju, Dahong

2014-12-12

The aim of this study was to evaluate the osteoprotective effect of aqueous Rhizoma Dioscoreae extract (RDE) on the alveolar bone of rats with ovariectomy-induced bone loss. Female Wistar rats were subjected to either ovariectomy or a sham operation (SHAM). The ovariectomized (OVX) rats were treated with vehicle (OVX) or RDE by oral gavage or with 17β-estradiol (E2) subcutaneously. After treatments, the bone mineral density (BMD), the three-dimensional bone architecture of the alveolar bone and the plasma biomarkers of bone turnover were analyzed to assess bone metabolism, and the histomorphometry of the alveolar bone was observed. Microarrays were used to evaluate gene expression profiles in alveolar bone from RDE-treated and OVX rats. The differential expression of genes was further analyzed using Ingenuity Pathway Analysis (IPA). The key findings were verified using real-time quantitative RT-PCR (qRT-PCR). Our results showed that RDE inhibited alveolar bone loss in OVX rats. Compared to the OVX rats, the RDE-treated rats showed upregulated expression levels of 207 genes and downregulated expression levels of 176 genes in the alveolar bone. The IPA showed that several genes had the potential to code for proteins that were involved in the Wnt/β-catenin signaling pathway (Wnt7a, Fzd2, Tcf3, Spp1, Frzb, Sfrp2 and Sfrp4) and the p38 MAPK signaling pathway (Il1rn and Mapk14). These experiments revealed that RDE could inhibit ovariectomy-induced alveolar bone loss in rats. The mechanism of this anti-osteopenic effect in alveolar bone may be involved in the reduced abnormal bone remodeling, which is associated with the modulation of the Wnt/β-catenin and the p38 MAPK signaling pathways via gene regulation.

Fungal Communication Requires the MAK-2 Pathway Elements STE-20 and RAS-2, the NRC-1 Adapter STE-50 and the MAP Kinase Scaffold HAM-5

PubMed Central

Dettmann, Anne; Heilig, Yvonne; Valerius, Oliver; Ludwig, Sarah; Seiler, Stephan

2014-01-01

Intercellular communication is critical for the survival of unicellular organisms as well as for the development and function of multicellular tissues. Cell-to-cell signaling is also required to develop the interconnected mycelial network characteristic of filamentous fungi and is a prerequisite for symbiotic and pathogenic host colonization achieved by molds. Somatic cell–cell communication and subsequent cell fusion is governed by the MAK-2 mitogen activated protein kinase (MAPK) cascade in the filamentous ascomycete model Neurospora crassa, yet the composition and mode of regulation of the MAK-2 pathway are currently unclear. In order to identify additional components involved in MAK-2 signaling we performed affinity purification experiments coupled to mass spectrometry with strains expressing functional GFP-fusion proteins of the MAPK cascade. This approach identified STE-50 as a regulatory subunit of the Ste11p homolog NRC-1 and HAM-5 as cell-communication-specific scaffold protein of the MAPK cascade. Moreover, we defined a network of proteins consisting of two Ste20-related kinases, the small GTPase RAS-2 and the adenylate cyclase capping protein CAP-1 that function upstream of the MAK-2 pathway and whose signals converge on the NRC-1/STE-50 MAP3K complex and the HAM-5 scaffold. Finally, our data suggest an involvement of the striatin interacting phosphatase and kinase (STRIPAK) complex, the casein kinase 2 heterodimer, the phospholipid flippase modulators YPK-1 and NRC-2 and motor protein-dependent vesicle trafficking in the regulation of MAK-2 pathway activity and function. Taken together, these data will have significant implications for our mechanistic understanding of MAPK signaling and for homotypic cell–cell communication in fungi and higher eukaryotes. PMID:25411845

Antiviral Potential of ERK/MAPK and PI3K/AKT/mTOR Signaling Modulation for Middle East Respiratory Syndrome Coronavirus Infection as Identified by Temporal Kinome Analysis

PubMed Central

Ork, Britini; Hart, Brit J.; Holbrook, Michael R.; Frieman, Matthew B.; Traynor, Dawn; Johnson, Reed F.; Dyall, Julie; Olinger, Gene G.; Hensley, Lisa E.

2014-01-01

Middle East respiratory syndrome coronavirus (MERS-CoV) is a lineage C betacoronavirus, and infections with this virus can result in acute respiratory syndrome with renal failure. Globally, MERS-CoV has been responsible for 877 laboratory-confirmed infections, including 317 deaths, since September 2012. As there is a paucity of information regarding the molecular pathogenesis associated with this virus or the identities of novel antiviral drug targets, we performed temporal kinome analysis on human hepatocytes infected with the Erasmus isolate of MERS-CoV with peptide kinome arrays. bioinformatics analysis of our kinome data, including pathway overrepresentation analysis (ORA) and functional network analysis, suggested that extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) and phosphoinositol 3-kinase (PI3K)/serine-threonine kinase (AKT)/mammalian target of rapamycin (mTOR) signaling responses were specifically modulated in response to MERS-CoV infection in vitro throughout the course of infection. The overrepresentation of specific intermediates within these pathways determined by pathway and functional network analysis of our kinome data correlated with similar patterns of phosphorylation determined through Western blot array analysis. In addition, analysis of the effects of specific kinase inhibitors on MERS-CoV infection in tissue culture models confirmed these cellular response observations. Further, we have demonstrated that a subset of licensed kinase inhibitors targeting the ERK/MAPK and PI3K/AKT/mTOR pathways significantly inhibited MERS-CoV replication in vitro whether they were added before or after viral infection. Taken together, our data suggest that ERK/MAPK and PI3K/AKT/mTOR signaling responses play important roles in MERS-CoV infection and may represent novel drug targets for therapeutic intervention strategies. PMID:25487801

Fungal communication requires the MAK-2 pathway elements STE-20 and RAS-2, the NRC-1 adapter STE-50 and the MAP kinase scaffold HAM-5.

PubMed

Dettmann, Anne; Heilig, Yvonne; Valerius, Oliver; Ludwig, Sarah; Seiler, Stephan

2014-11-01

Intercellular communication is critical for the survival of unicellular organisms as well as for the development and function of multicellular tissues. Cell-to-cell signaling is also required to develop the interconnected mycelial network characteristic of filamentous fungi and is a prerequisite for symbiotic and pathogenic host colonization achieved by molds. Somatic cell-cell communication and subsequent cell fusion is governed by the MAK-2 mitogen activated protein kinase (MAPK) cascade in the filamentous ascomycete model Neurospora crassa, yet the composition and mode of regulation of the MAK-2 pathway are currently unclear. In order to identify additional components involved in MAK-2 signaling we performed affinity purification experiments coupled to mass spectrometry with strains expressing functional GFP-fusion proteins of the MAPK cascade. This approach identified STE-50 as a regulatory subunit of the Ste11p homolog NRC-1 and HAM-5 as cell-communication-specific scaffold protein of the MAPK cascade. Moreover, we defined a network of proteins consisting of two Ste20-related kinases, the small GTPase RAS-2 and the adenylate cyclase capping protein CAP-1 that function upstream of the MAK-2 pathway and whose signals converge on the NRC-1/STE-50 MAP3K complex and the HAM-5 scaffold. Finally, our data suggest an involvement of the striatin interacting phosphatase and kinase (STRIPAK) complex, the casein kinase 2 heterodimer, the phospholipid flippase modulators YPK-1 and NRC-2 and motor protein-dependent vesicle trafficking in the regulation of MAK-2 pathway activity and function. Taken together, these data will have significant implications for our mechanistic understanding of MAPK signaling and for homotypic cell-cell communication in fungi and higher eukaryotes.

Six post-implantation lethal knockouts of genes for lipophilic MAPK pathway proteins are expressed in preimplantation mouse embryos and trophoblast stem cells.

PubMed

Xie, Yufen; Wang, Yingchun; Sun, Tong; Wang, Fangfei; Trostinskaia, Anna; Puscheck, Elizabeth; Rappolee, Daniel A

2005-05-01

Mitogen-activated protein kinase (MAPK) signaling pathways play an important role in controlling embryonic proliferation and differentiation. It has been demonstrated that sequential lipophilic signal transduction mediators that participate in the MAPK pathway are null post-implantation lethal. It is not clear why the lethality of these null mutants arises after implantation and not before. One hypothesis is that the gene product of these post-implantation lethal null mutants are not present before implantation in normal embryos and do not have function until after implantation. To test this hypothesis, we selected a set of lipophilic genes mediating MAPK signal transduction pathways whose null mutants result in early peri-implantation or placental lethality. These included FRS2alpha, GAB1, GRB2, SOS1, Raf-B, and Raf1. Products of these selected genes were detected and their locations and functions indicated by indirect immunocytochemistry and Western blotting for proteins and RT-polymerase chain reaction (PCR) for mRNA transcription. We report here that all six signal mediators are detected at the protein level in preimplantation mouse embryo, placental trophoblasts, and in cultured trophoblast stem cells (TSC). Proteins are all detected in E3.5 embryos at a time when the first known mitogenic intercellular communication has been documented. mRNA transcripts of two post-implantation null mutant genes are expressed in mouse preimplantation embryos and unfertilized eggs. These mRNA transcripts were detected as maternal mRNA in unfertilized eggs that could delay the lethality of null mutants. All of the proteins were detected in the cytoplasm or in the cell membrane. This study of spatial and temporal expression revealed that all of these six null mutants post-implantation genes in MAPK pathway are expressed and, where tested, phosphorylated/activated proteins are detected in the blastocyst. Studies on RNA expression using RT-PCR suggest that maternal RNA could play an important role in delaying the presence of the lethal phenotype of null mutations. Copyright (c) 2005 Wiley-Liss, Inc.

Dissecting the role of histidine kinase and HOG1 mitogen-activated protein kinase signalling in stress tolerance and pathogenicity of Parastagonospora nodorum on wheat

PubMed Central

John, Evan; Lopez-Ruiz, Francisco; Rybak, Kasia; Mousley, Carl J.; Oliver, Richard P.

2016-01-01

The HOG1 mitogen-activated protein kinase (MAPK) pathway is activated through two-component histidine kinase (HK) signalling. This pathway was first characterized in the budding yeast Saccharomyces cerevisiae as a regulator of osmotolerance. The fungus Parastagonospora nodorum is the causal agent of septoria nodorum blotch of wheat. This pathogen uses host-specific effectors in tandem with general pathogenicity mechanisms to carry out its infection process. Genes showing strong sequence homology to S. cerevisiae HOG1 signalling pathway genes have been identified in the genome of P. nodorum. In this study, we examined the role of the pathway in the virulence of P. nodorum on wheat by disrupting putative pathway component genes: HOG1 (SNOG_13296) MAPK and NIK1 (SNOG_11631) hybrid HK. Mutants deleted in NIK1 and HOG1 were insensitive to dicarboximide and phenylpyrrole fungicides, but not a fungicide that targets ergosterol biosynthesis. Furthermore, both Δnik1 and Δhog1 mutants showed increased sensitivity to hyperosmotic stress. However, HOG1, but not NIK1, is required for tolerance to elevated temperatures. HOG1 deletion conferred increased tolerance to 6-methoxy-2-benzoxazolinone, a cereal phytoalexin. This suggests that the HOG1 signalling pathway is not exclusively associated with NIK1. Both Δnik1 and Δhog1 mutants retained the ability to infect and cause necrotic lesions on wheat. However, we observed that the Δhog1 mutation resulted in reduced production of pycnidia, asexual fruiting bodies that facilitate spore dispersal during late infection. Our study demonstrated the overlapping and distinct roles of a HOG1 MAPK and two-component HK signalling in P. nodorum growth and pathogenicity. PMID:26978567

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

PubMed

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

2001-11-20

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

Cognitive Dysfunctions in Intellectual Disabilities: The Contributions of the Ras-MAPK and PI3K-AKT-mTOR Pathways.

PubMed

Borrie, Sarah C; Brems, Hilde; Legius, Eric; Bagni, Claudia

2017-08-31

The Ras-MAPK and PI3K-AKT-mTOR signaling cascades were originally identified as cancer regulatory pathways but have now been demonstrated to be critical for synaptic plasticity and behavior. Neurodevelopmental disorders arising from mutations in these pathways exhibit related neurological phenotypes, including cognitive dysfunction, autism, and intellectual disability. The downstream targets of these pathways include regulation of transcription and protein synthesis. Other disorders that affect protein translation include fragile X syndrome (an important cause of syndromal autism), and other translational regulators are now also linked to autism. Here, we review how mechanisms of synaptic plasticity have been revealed by studies of mouse models for Ras-MAPK, PI3K-AKT-mTOR, and translation regulatory pathway disorders. We discuss the face validity of these mouse models and review current progress in clinical trials directed at ameliorating cognitive and behavioral symptoms.

Activation of the MAPK pathway is a common event in uveal melanomas although it rarely occurs through mutation of BRAF or RAS.

PubMed

Zuidervaart, W; van Nieuwpoort, F; Stark, M; Dijkman, R; Packer, L; Borgstein, A-M; Pavey, S; van der Velden, P; Out, C; Jager, M J; Hayward, N K; Gruis, N A

2005-06-06

In contrast to cutaneous melanoma, there is no evidence that BRAF mutations are involved in the activation of the mitogen-activated protein kinase (MAPK) pathway in uveal melanoma, although there is increasing evidence that this pathway is activated frequently in the latter tumours. In this study, we performed mutation analysis of the RAS and BRAF genes in a panel of 11 uveal melanoma cell lines and 19 primary uveal melanoma tumours. In addition, Western blot and immunohistochemical analyses were performed on downstream members of the MAPK pathway in order to assess the contribution of each of these components. No mutations were found in any of the three RAS gene family members and only one cell line carried a BRAF mutation (V599E). Despite this, mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK), ERK and ELK were constitutively activated in all samples. These data suggest that activation of the MAPK pathway is commonly involved in the development of uveal melanoma, but occurs through a mechanism different to that of cutaneous melanoma.

Activation of the MAPK pathway is a common event in uveal melanomas although it rarely occurs through mutation of BRAF or RAS

PubMed Central

Zuidervaart, W; van Nieuwpoort, F; Stark, M; Dijkman, R; Packer, L; Borgstein, A-M; Pavey, S; van der Velden, P; Out, C; Jager, M J; Hayward, N K; Gruis, N A

2005-01-01

In contrast to cutaneous melanoma, there is no evidence that BRAF mutations are involved in the activation of the mitogen-activated protein kinase (MAPK) pathway in uveal melanoma, although there is increasing evidence that this pathway is activated frequently in the latter tumours. In this study, we performed mutation analysis of the RAS and BRAF genes in a panel of 11 uveal melanoma cell lines and 19 primary uveal melanoma tumours. In addition, Western blot and immunohistochemical analyses were performed on downstream members of the MAPK pathway in order to assess the contribution of each of these components. No mutations were found in any of the three RAS gene family members and only one cell line carried a BRAF mutation (V599E). Despite this, mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK), ERK and ELK were constitutively activated in all samples. These data suggest that activation of the MAPK pathway is commonly involved in the development of uveal melanoma, but occurs through a mechanism different to that of cutaneous melanoma. PMID:15928660

The node-weighted Steiner tree approach to identify elements of cancer-related signaling pathways.

PubMed

Sun, Yahui; Ma, Chenkai; Halgamuge, Saman

2017-12-28

Cancer constitutes a momentous health burden in our society. Critical information on cancer may be hidden in its signaling pathways. However, even though a large amount of money has been spent on cancer research, some critical information on cancer-related signaling pathways still remains elusive. Hence, new works towards a complete understanding of cancer-related signaling pathways will greatly benefit the prevention, diagnosis, and treatment of cancer. We propose the node-weighted Steiner tree approach to identify important elements of cancer-related signaling pathways at the level of proteins. This new approach has advantages over previous approaches since it is fast in processing large protein-protein interaction networks. We apply this new approach to identify important elements of two well-known cancer-related signaling pathways: PI3K/Akt and MAPK. First, we generate a node-weighted protein-protein interaction network using protein and signaling pathway data. Second, we modify and use two preprocessing techniques and a state-of-the-art Steiner tree algorithm to identify a subnetwork in the generated network. Third, we propose two new metrics to select important elements from this subnetwork. On a commonly used personal computer, this new approach takes less than 2 s to identify the important elements of PI3K/Akt and MAPK signaling pathways in a large node-weighted protein-protein interaction network with 16,843 vertices and 1,736,922 edges. We further analyze and demonstrate the significance of these identified elements to cancer signal transduction by exploring previously reported experimental evidences. Our node-weighted Steiner tree approach is shown to be both fast and effective to identify important elements of cancer-related signaling pathways. Furthermore, it may provide new perspectives into the identification of signaling pathways for other human diseases.

Inhibition of mitogen-activated protein kinase Erk1/2 promotes protein degradation of ATP binding cassette transporters A1 and G1 in CHO and HuH7 cells.

PubMed

Mulay, Vishwaroop; Wood, Peta; Manetsch, Melanie; Darabi, Masoud; Cairns, Rose; Hoque, Monira; Chan, Karen Cecilia; Reverter, Meritxell; Alvarez-Guaita, Anna; Rye, Kerry-Anne; Rentero, Carles; Heeren, Joerg; Enrich, Carlos; Grewal, Thomas

2013-01-01

Signal transduction modulates expression and activity of cholesterol transporters. We recently demonstrated that the Ras/mitogen-activated protein kinase (MAPK) signaling cascade regulates protein stability of Scavenger Receptor BI (SR-BI) through Proliferator Activator Receptor (PPARα) -dependent degradation pathways. In addition, MAPK (Mek/Erk 1/2) inhibition has been shown to influence liver X receptor (LXR) -inducible ATP Binding Cassette (ABC) transporter ABCA1 expression in macrophages. Here we investigated if Ras/MAPK signaling could alter expression and activity of ABCA1 and ABCG1 in steroidogenic and hepatic cell lines. We demonstrate that in Chinese Hamster Ovary (CHO) cells and human hepatic HuH7 cells, extracellular signal-regulated kinase 1/2 (Erk1/2) inhibition reduces PPARα-inducible ABCA1 protein levels, while ectopic expression of constitutively active H-Ras, K-Ras and MAPK/Erk kinase 1 (Mek1) increases ABCA1 protein expression, respectively. Furthermore, Mek1/2 inhibitors reduce ABCG1 protein levels in ABCG1 overexpressing CHO cells (CHO-ABCG1) and human embryonic kidney 293 (HEK293) cells treated with LXR agonist. This correlates with Mek1/2 inhibition reducing ABCG1 cell surface expression and decreasing cholesterol efflux onto High Density Lipoproteins (HDL). Real Time reverse transcriptase polymerase chain reaction (RT-PCR) and protein turnover studies reveal that Mek1/2 inhibitors do not target transcriptional regulation of ABCA1 and ABCG1, but promote ABCA1 and ABCG1 protein degradation in HuH7 and CHO cells, respectively. In line with published data from mouse macrophages, blocking Mek1/2 activity upregulates ABCA1 and ABCG1 protein levels in human THP1 macrophages, indicating opposite roles for the Ras/MAPK pathway in the regulation of ABC transporter activity in macrophages compared to steroidogenic and hepatic cell types. In summary, this study suggests that Ras/MAPK signaling modulates PPARα- and LXR-dependent protein degradation pathways in a cell-specific manner to regulate the expression levels of ABCA1 and ABCG1 transporters.

C. elegans Vulva Induction: An In Vivo Model to Study Epidermal Growth Factor Receptor Signaling and Trafficking.

PubMed

Gauthier, Kimberley; Rocheleau, Christian E

2017-01-01

Epidermal growth factor receptor (EGFR)-mediated activation of the canonical Ras/MAPK signaling cascade is responsible for cell proliferation and cell growth. This signaling pathway is frequently overactivated in epithelial cancers; therefore, studying regulation of this pathway is crucial not only for our fundamental understanding of cell biology but also for our ability to treat EGFR-related disease. Genetic model organisms such as Caenorhabditis elegans, a hermaphroditic nematode, played a vital role in identifying components of the EGFR/Ras/MAPK pathway and delineating their order of function, and continues to play a role in identifying novel regulators of the pathway. Polarized activation of LET-23, the C. elegans homolog of EGFR, is responsible for induction of the vulval cell fate; perturbations in this signaling pathway produce either a vulvaless or multivulva phenotype. The translucent cuticle of the nematode facilitates in vivo visualization of the receptor, revealing that localization of LET-23 EGFR is tightly regulated and linked to its function. In this chapter, we review the methods used to harness vulva development as a tool for studying EGFR signaling and trafficking in C. elegans.

Regulation of Hippo signalling by p38 signalling.

PubMed

Huang, Dashun; Li, Xiaojiao; Sun, Li; Huang, Ping; Ying, Hao; Wang, Hui; Wu, Jiarui; Song, Haiyun

2016-08-01

The Hippo signalling pathway has a crucial role in growth control during development, and its dysregulation contributes to tumorigenesis. Recent studies uncover multiple upstream regulatory inputs into Hippo signalling, which affects phosphorylation of the transcriptional coactivator Yki/YAP/TAZ by Wts/Lats. Here we identify the p38 mitogen-activated protein kinase (MAPK) pathway as a new upstream branch of the Hippo pathway. In Drosophila, overexpression of MAPKK gene licorne (lic), or MAPKKK gene Mekk1, promotes Yki activity and induces Hippo target gene expression. Loss-of-function studies show that lic regulates Hippo signalling in ovary follicle cells and in the wing disc. Epistasis analysis indicates that Mekk1 and lic affect Hippo signalling via p38b and wts We further demonstrate that the Mekk1-Lic-p38b cascade inhibits Hippo signalling by promoting F-actin accumulation and Jub phosphorylation. In addition, p38 signalling modulates actin filaments and Hippo signalling in parallel to small GTPases Ras, Rac1, and Rho1. Lastly, we show that p38 signalling regulates Hippo signalling in mammalian cell lines. The Lic homologue MKK3 promotes nuclear localization of YAP via the actin cytoskeleton. Upregulation or downregulation of the p38 pathway regulates YAP-mediated transcription. Our work thus reveals a conserved crosstalk between the p38 MAPK pathway and the Hippo pathway in growth regulation. © The Author (2016). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS.

SIRT1 regulates MAPK pathways in vitiligo skin: insight into the molecular pathways of cell survival

PubMed Central

Becatti, Matteo; Fiorillo, Claudia; Barygina, Victoria; Cecchi, Cristina; Lotti, Torello; Prignano, Francesca; Silvestro, Agrippino; Nassi, Paolo; Taddei, Niccolò

2014-01-01

Vitiligo is an acquired and progressive hypomelanotic disease that manifests as circumscribed depigmented patches on the skin. The aetiology of vitiligo remains unclear, but recent experimental data underline the interactions between melanocytes and other typical skin cells, particularly keratinocytes. Our previous results indicate that keratinocytes from perilesional skin show the features of damaged cells. Sirtuins (silent mating type information regulation 2 homolog) 1, well-known modulators of lifespan in many species, have a role in gene repression, metabolic control, apoptosis and cell survival, DNA repair, development, inflammation, neuroprotection and healthy ageing. In the literature there is no evidence for SIRT1 signalling in vitiligo and its possible involvement in disease progression. Here, biopsies were taken from the perilesional skin of 16 patients suffering from non-segmental vitiligo and SIRT1 signalling was investigated in these cells. For the first time, a new SIRT1/Akt, also known as Protein Kinase B (PKB)/mitogen-activated protein kinase (MAPK) signalling has been revealed in vitiligo. SIRT1 regulates MAPK pathway via Akt-apoptosis signal-regulating kinase-1 and down-regulates pro-apoptotic molecules, leading to decreased oxidative stress and apoptotic cell death in perilesional vitiligo keratinocytes. We therefore propose SIRT1 activation as a novel way of protecting perilesional vitiligo keratinocytes from damage. PMID:24410795

Tanshinone IIA inhibits AGEs-induced proliferation and migration of cultured vascular smooth muscle cells by suppressing ERK1/2 MAPK signaling.

PubMed

Lu, Ming; Luo, Ying; Hu, Pengfei; Dou, Liping; Huang, Shuwei

2018-01-01

Vascular smooth muscle cells (VSMCs) play a key role in the pathogenesis of diabetic vascular disease. Our current study sought to explore the effects of tanshinone IIA on the proliferation and migration of VSMCs induced by advanced glycation end products (AGEs). In this study, we examined the effects of tanshinone IIA by cell proliferation assay and cell migration assay. And we explored the underlying mechanism by Western blotting. AGEs significantly induced the proliferation and migration of VSMCs, but treatment with tanshinone IIA attenuated these effects. AGEs could increase the activity of the ERK1/2 and p38 pathways but not the JNK pathway. Treatment with tanshinone IIA inhibited the AGEs-induced activation of the ERK1/2 pathway but not the p38 pathway. Tanshinone IIA inhibits AGEs-induced proliferation and migration of VSMCs by suppressing the ERK1/2 MAPK signaling pathway.

Fragment-based drug discovery of potent and selective MKK3/6 inhibitors.

PubMed

Adams, Mark; Kobayashi, Toshitake; Lawson, J David; Saitoh, Morihisa; Shimokawa, Kenichiro; Bigi, Simone V; Hixon, Mark S; Smith, Christopher R; Tatamiya, Takayuki; Goto, Masayuki; Russo, Joseph; Grimshaw, Charles E; Swann, Steven

2016-02-01

The MAPK signaling cascade, comprised of several linear and intersecting pathways, propagates signaling into the nucleus resulting in cytokine and chemokine release. The Map Kinase Kinase isoforms 3 and 6 (MKK3 and MKK6) are responsible for the phosphorylation and activation of p38, and are hypothesized to play a key role in regulating this pathway without the redundancy seen in downstream effectors. Using FBDD, we have discovered efficient and selective inhibitors of MKK3 and MKK6 that can serve as tool molecules to help further understand the role of these kinases in MAPK signaling, and the potential impact of inhibiting kinases upstream of p38. Copyright © 2015 Elsevier Ltd. All rights reserved.

Endothelial progenitor cells proliferated via MEK-dependent p42 MAPK signaling pathway.

PubMed

Sandra, Ferry; Oktaviono, Yudi Her; Widodo, Mohammad Aris; Dirgantara, Yanni; Chouw, Angliana; Sargowo, Djanggan

2015-02-01

Endothelial progenitor cells (EPCs) clinical applications have been well reported. However, due to low number of EPCs that could be isolated, EPCs expansion study became one of the main focuses. Some optimized mediums to culture EPCs were currently available. However, the proliferation signaling pathway is not clearly disclosed yet. Peripheral blood was collected from eight healthy subjects, followed by mononuclear cells (MNCs) isolation. MNCs were then prepared and cultured for 2 days. After that, non-adherent cells were harvested and further cultured for 3 days. Resulted colony-forming unit (CFU)-Hill colonies were documented and enumerated under an inverted light microscope. To detect membrane markers, immunofluorescence was performed to detect CD34, VEGFR-2, and CD133. Cell documentation was conducted under a fluorescence microscope. To check cell proliferation, XTT Cell Proliferation Assay Kit was used according to kit insert. To detect possible activation of p44/42 MAPK, western blot was performed to detect p44/42 MAPK and phosphorylated p44/42 MAPK. All visualized bands were captured and quantified. Our results showed that EPCs markers (CD34, CD133 and VEGFR-2) were detected in 3 days culture. From XTT cell proliferation assay and CFU enumeration results, we found that EPCs proliferated significantly (p = 0.012) with addition of supplement. Phosphorylated-p42 MAPK expression of EPCs treated with supplement was significantly higher than the one of EPCs without treatment. Significant inhibition of p42 MAPK phosphorylation by U0126 was observed (p = 0.012). By pretreatment of U0126, number of viable cells and CFUs treated with supplement was significantly decreased (p = 0.012). Our results showed that MEK-dependent p42 MAPK pathway might play an important role in EPCs proliferation.

Activation of mitogen-activated protein kinase/extracellular signal-regulated kinase in hippocampal circuitry is required for consolidation and reconsolidation of recognition memory.

PubMed

Kelly, Aine; Laroche, Serge; Davis, Sabrina

2003-06-15

Consolidation and reconsolidation of long-term memory have been shown to be dependent on the synthesis of new proteins, but the specific molecular mechanisms underlying these events remain to be elucidated. The mitogen-activated protein kinase (MAPK) pathway can trigger genomic responses in neurons, leading to changes in protein synthesis, and several studies have identified its pivotal role in synaptic plasticity and long-term memory formation. In this study, we analyze the involvement of this pathway in the consolidation and reconsolidation of long-term recognition memory, using an object recognition task. We show that inhibition of the MAPK pathway by intracerebroventricular injection of the MEK [MAPK/extracellular signal-regulated kinase (ERK)] inhibitor UO126 blocks consolidation of object recognition memory but does not affect short-term memory. Brain regions of the entorhinal cortex-hippocampal circuitry were analyzed for ERK activation, and it was shown that consolidation of recognition memory was associated with increased phosphorylation of ERK in the dentate gyrus and entorhinal cortex, although total expression of ERK was unchanged. We also report that inhibition of the MAPK pathway blocks reconsolidation of recognition memory, and this was shown to be dependent on reactivation of the memory trace by brief reexposure to the objects. In addition, reconsolidation of memory was associated with an increase in the phosphorylation of ERK in entorhinal cortex and CA1. In summary, our data show that the MAPK kinase pathway is required for both consolidation and reconsolidation of long-term recognition memory, and that this is associated with hyperphosphorylation of ERK in different subregions of the entorhinal cortex-hippocampal circuitry.

Regulation of mitogen-activated protein kinase 3/1 activity during meiosis resumption in mammals.

PubMed

Prochazka, Radek; Blaha, Milan

2015-01-01

In vivo, resumption of oocyte meiosis occurs in large ovarian follicles after the preovulatory surge of luteinizing hormone (LH). The LH surge leads to the activation of a broad signaling network in mural granulosa cells equipped with LH receptors. The signals generated in the mural granulosa cells are further augmented by locally produced peptides or steroids and transferred to the cumulus cell compartment and the oocyte itself. Over the last decade, essential progress has been made in the identification of molecular events associated with the final maturation and ovulation of mammalian oocytes. All new evidence argues for a multiple roles of mitogen-activated protein kinase 3/1 (MAPK3/1) in the gonadotropin-induced ovulation processes. However, the knowledge of gonadotropin-induced signaling pathways leading to MAPK3/1 activation in follicular cells seems limited. To date, only the LH-induced transactivation of the epidermal growth factor receptor/MAPK3/1 pathway has been described in granulosa/cumulus cells even though other mechanisms of MAPK3/1 activation have been detected in other types of cells. In this review, we aimed to summarize recent advances in the elucidation of gonadotropin-induced mechanisms leading to the activation of MAPK3/1 in preovulatory follicles and cultured cumulus-oocyte complexes and to point out a specific role of this kinase in the processes accompanying final maturation of the mammalian oocyte.

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

DOE PAGES

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

2015-06-16

Rat sarcoma (Ras) GTPases regulate cell proliferation and survival through effector pathways including Raf-MAPK, and are the most frequently mutated genes in human cancer. Although it is well established that Ras activity requires binding to both GTP and the membrane, details of how Ras operates on the cell membrane to activate its effectors remain elusive. Efforts to target mutant Ras in human cancers to therapeutic benefit have also been largely unsuccessful. Here we show that Ras-GTP forms dimers to activate MAPK. We used quantitative photoactivated localization microscopy (PALM) to analyze the nanoscale spatial organization of PAmCherry1-tagged KRas 4B (hereafter referredmore » to KRas) on the cell membrane under various signaling conditions. We found that at endogenous expression levels KRas forms dimers, and KRas G12D, a mutant that constitutively binds GTP, activates MAPK. Overexpression of KRas leads to formation of higher order Ras nanoclusters. Conversely, at lower expression levels, KRas G12D is monomeric and activates MAPK only when artificially dimerized. Moreover, dimerization and signaling of KRas are both dependent on an intact CAAX (C, cysteine; A, aliphatic; X, any amino acid) motif that is also known to mediate membrane localization. These results reveal a new, dimerization-dependent signaling mechanism of Ras, and suggest Ras dimers as a potential therapeutic target in mutant Ras-driven tumors.« less

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

PubMed Central

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

2015-01-01

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

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

Wang, Yuxia; Gao, Ying; Cheng, Hairong

Cervical cancer is one of the most common carcinomas in the female reproductive system. Treatment of cervical cancer involves surgical removal and chemotherapy. Resistance to platinum-based chemotherapy drugs including cisplatin has increasingly become an important problem in the treatment of cervical cancer patients. We found in this study that stanniocalcin 2 (STC2) expression was upregulated in both cervical cancer tissues and cell lines. The levels of STC2 expression in cervical cancer cell lines were positively correlated with the rate of cell proliferation. Furthermore, in cisplatin resistant cervical cancer cells, the levels of STC2 expression were significantly elevated. Modulation of STC2more » expression by siRNA or overexpression in cisplatin resistant cells resulted in altered cell survival, apoptosis, and cisplatin resistance. Finally, we found that there was significant difference in the activity of the MAPK signaling pathway between cisplatin sensitive and resistant cervical cancer cells, and that STC2 could regulate the activity of the MAPK signaling pathway. - Highlights: • STC2 was upregulated in cervical cancer and promoted cervical cancer cell proliferation. • Cisplatin resistant cells had elevated STC2 levels and enhanced proliferation. • STC2 regulated cisplatin chemosensitivity in cervical cancer cells. • STC2 regulated the activity of the MAPK signaling pathway.« less

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

Upregulation of MAPK/Erk and PI3K/Akt pathways in ulcerative colitis-associated colon cancer.

PubMed

Setia, Shruti; Nehru, Bimla; Sanyal, Sankar Nath

2014-10-01

An extracellular signal like a cytokine or chemokine, secreted in the inflammatory microenvironment can activate the mitogen activated protein kinase (MAPK) pathway by binding to a cytokine receptor tyrosine kinase, which further activates tyrosine kinases such as Janus Kinase-3 (Jak-3). This signal is transferred from Jak-3 to the DNA in the nucleus of the cell by a chain of kinases, ultimately activating extracellular receptor kinase (Erk/MAPK). The latter phosphorylates c-myc, an oncogene, which alters the levels and activities of many transcription factors leading to cell survival, proliferation and invasion. The oncogenic PI3K pathway plays a similar role by activating c-myc, leading to cell survival and proliferation. The present study explores the role of ulcerative colitis in colon cancer by investigating the activities of tyrosine kinase activated MAPK pathway and various components of the PI3K pathway including PI3K, PTEN, PDK1, GSK3β, Akt, mTOR, Wnt and β-catenin. This was done by western blot and fluorescent immunohistochemical analysis of the above-mentioned proteins. Also, the morphological and histological investigation of the colonic samples from various animal groups revealed significant alterations as compared to the control in both inflammatory as well as carcinogenic conditions. These effects were reduced to a large extent by the co-administration of celecoxib, a second-generation non-steroidal anti-inflammatory drug (NSAID). Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Differential pathway coupling efficiency of the activated insulin receptor drives signaling selectivity by XMetA, an allosteric partial agonist antibody

USDA-ARS?s Scientific Manuscript database

XMetA, an anti-insulin receptor (IR) monoclonal antibody, is an allosteric partial agonist of the IR. We have previously reported that XMetA activates the “metabolic-biased” Akt kinase signaling pathway while having little or no effect on the “mitogenic” MAPK signaling pathwayof ERK 1/2. To inves...

Differential pathway coupling efficiency of the activated insulin receptor drives signaling selectivity by xmeta, an allosteric partial agonist antibody

USDA-ARS?s Scientific Manuscript database

XMetA, an anti-insulin receptor (IR) monoclonal antibody, is an allosteric partial agonist of the IR. We have previously reported that XMetA activates the “metabolic-biased” Akt kinase signaling pathway while having little or no effect on the “mitogenic” MAPK signaling pathwayof ERK 1/2. To inves...

Arctigenin induces apoptosis in colon cancer cells through ROS/p38MAPK pathway.

PubMed

Li, Qing-chun; Liang, Yun; Tian, Yuan; Hu, Guang-rui

2016-01-01

In the current study the antiproliferative effect of arctigenin, plant lignin, was evaluated on human colon cancer cell line HT-29. Furthermore, attempts were made to explore the signaling mechanism which may be responsible for its effect. Cell growth inhibition was assessed by MTT and LDH assays. Flow cytometric analysis was performed to determine cell arrest in the cell cycle phase and apoptosis. Furthermore, to confirm the apoptotic activity of arctigenin, caspase-9 and -3 activities analysis was performed. The levels of reactive oxygen species (ROS) and p38 mitogen activated protein kinase (MAPK) were investigated to determine their role in inducing apoptosis in arctigenin-treated HT-29 colon cancer cell line. MTT and LDH results demonstrated significant cell growth inhibitory effect of arctigenin on HT-29 cells in a dose-dependent manner. Furthermore, increase in cell number arrested at G2/M phase was observed in flow cytometric analysis upon arctigenin treatment. In addition, arctigenin increased the apoptotic ratio in a dose-dependent manner. The involvement of intrinsic apoptotic pathway was indicated by the activation of caspase-9 and -3. Moreover, increased ROS production, activation of p38 MAPK and changes in mitochondrial membrane potential (ΔΨm) also revealed the role of intrinsic apoptotic signaling pathway in cell growth inhibition after arctigenin exposure. Arctigenin induces apoptosis in HT-29 colon cancer cells by regulating ROS and p38 MAPK pathways.

A shared molecular mechanism underlies the human rasopathies Legius syndrome and Neurofibromatosis-1

PubMed Central

Stowe, Irma B.; Mercado, Ellen L.; Stowe, Timothy R.; Bell, Erika L.; Oses-Prieto, Juan A.; Hernández, Hilda; Burlingame, Alma L.; McCormick, Frank

2012-01-01

The Ras/mitogen-activated protein kinase (MAPK) pathway plays a critical role in transducing mitogenic signals from receptor tyrosine kinases. Loss-of-function mutations in one feedback regulator of Ras/MAPK signaling, SPRED1 (Sprouty-related protein with an EVH1 domain), cause Legius syndrome, an autosomal dominant human disorder that resembles Neurofibromatosis-1 (NF1). Spred1 functions as a negative regulator of the Ras/MAPK pathway; however, the underlying molecular mechanism is poorly understood. Here we show that neurofibromin, the NF1 gene product, is a Spred1-interacting protein that is necessary for Spred1's inhibitory function. We show that Spred1 binding induces the plasma membrane localization of NF1, which subsequently down-regulates Ras-GTP levels. This novel mechanism for the regulation of neurofibromin provides a molecular bridge for understanding the overlapping pathophysiology of NF1 and Legius syndrome. PMID:22751498

A calcium-sensing receptor mutation causing hypocalcemia disrupts a transmembrane salt bridge to activate β-arrestin-biased signaling.

PubMed

Gorvin, Caroline M; Babinsky, Valerie N; Malinauskas, Tomas; Nissen, Peter H; Schou, Anders J; Hanyaloglu, Aylin C; Siebold, Christian; Jones, E Yvonne; Hannan, Fadil M; Thakker, Rajesh V

2018-02-20

The calcium-sensing receptor (CaSR) is a G protein-coupled receptor (GPCR) that signals through G q/11 and G i/o to stimulate cytosolic calcium (Ca 2+ i ) and mitogen-activated protein kinase (MAPK) signaling to control extracellular calcium homeostasis. Studies of loss- and gain-of-function CASR mutations, which cause familial hypocalciuric hypercalcemia type 1 (FHH1) and autosomal dominant hypocalcemia type 1 (ADH1), respectively, have revealed that the CaSR signals in a biased manner. Thus, some mutations associated with FHH1 lead to signaling predominantly through the MAPK pathway, whereas mutations associated with ADH1 preferentially enhance Ca 2+ i responses. We report a previously unidentified ADH1-associated R680G CaSR mutation, which led to the identification of a CaSR structural motif that mediates biased signaling. Expressing CaSR R680G in HEK 293 cells showed that this mutation increased MAPK signaling without altering Ca 2+ i responses. Moreover, this gain of function in MAPK activity occurred independently of G q/11 and G i/o and was mediated instead by a noncanonical pathway involving β-arrestin proteins. Homology modeling and mutagenesis studies showed that the R680G CaSR mutation selectively enhanced β-arrestin signaling by disrupting a salt bridge formed between Arg 680 and Glu 767 , which are located in CaSR transmembrane domain 3 and extracellular loop 2, respectively. Thus, our results demonstrate CaSR signaling through β-arrestin and the importance of the Arg 680 -Glu 767 salt bridge in mediating signaling bias. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Curcumin suppresses JNK pathway to attenuate BPA-induced insulin resistance in LO2 cells.

PubMed

Geng, Shanshan; Wang, Shijia; Zhu, Weiwei; Xie, Chunfeng; Li, Xiaoting; Wu, Jieshu; Zhu, Jianyun; Jiang, Ye; Yang, Xue; Li, Yuan; Chen, Yue; Wang, Xiaoqian; Meng, Yu; Zhong, Caiyun

2018-01-01

To examine whether curcumin has protective effect on insulin resistance induced by bisphenol A (BPA) in LO2 cells and whether this effect was mediated by inhibiting the inflammatory mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) pathways. LO2 cells were stimulated with BPA in the presence or absence of curcumin for 5 days. Glucose consumption, activation of insulin signaling, MAPKs and NF-κB pathways, levels of inflammatory cytokines and MDA production were analyzed. Curcumin prevented BPA-induced reduction of glucose consumption and suppression of insulin signaling pathway, indicating curcumin alleviated BPA-triggered insulin resistance in LO2 cells. mRNA and proteins levels of TNF-α and IL-6, as well as MDA level in LO2 cells treated with BPA were decreased by curcumin. Furthermore, curcumin downregulated the activation of p38, JNK, and NF-κB pathways upon stimulation with BPA. Inhibition of JNK pathway, but not p38 nor NF-κB pathway, improved glucose consumption and insulin signaling in BPA-treated LO2 cells. Curcumin inhibits BPA-induced insulin resistance by suppressing JNK pathway. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

A novel stilbene-like compound that inhibits melanoma growth by regulating melanocyte differentiation and proliferation.

PubMed

Stueven, Noah A; Schlaeger, Nicholas M; Monte, Aaron P; Hwang, Sheng-Ping L; Huang, Cheng-Chen

2017-12-15

Melanoma is the most aggressive form of skin cancer. Current challenges to melanoma therapy include the adverse effects from immunobiologics, resistance to drugs targeting the MAPK pathway, intricate interaction of many signal pathways, and cancer heterogeneity. Thus combinational therapy with drugs targeting multiple signaling pathways becomes a new promising therapy. Here, we report a family of stilbene-like compounds called A11 that can inhibit melanoma growth in both melanoma-forming zebrafish embryos and mouse melanoma cells. The growth inhibition by A11 is a result of mitosis reduction but not apoptosis enhancement. Meanwhile, A11 activates both MAPK and Akt signaling pathways. Many A11-treated mouse melanoma cells exhibit morphological changes and resemble normal melanocytes. Furthermore, we found that A11 causes down-regulation of melanocyte differentiation genes, including Pax3 and MITF. Together, our results suggest that A11 could be a new melanoma therapeutic agent by inhibiting melanocyte differentiation and proliferation. Copyright © 2017 Elsevier Inc. All rights reserved.

Magnolol inhibits tumor necrosis factor-α-induced ICAM-1 expression via suppressing NF-κB and MAPK signaling pathways in human lung epithelial cells.

PubMed

Chunlian, Wu; Heyong, Wang; Jia, Xu; Jie, Huang; Xi, Chen; Gentao, Liu

2014-12-01

Magnolol is a traditional Chinese medicine from the root and bark of Magnolia officinalis. It has long been used to treat anxiety, cough, headache and allergies, as well as a variety of inflammations. Lung inflammation is a key event in the pathogenesis of asthma and chronic obstructive pulmonary disease. The present study sought to examine the effects of magnolol on tumor necrosis factor (TNF)-α-induced upregulation of intercellular adhesion molecule-1 (ICAM-1), activation of the nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling pathway in cultured human pulmonary epithelial cells, and adhesion of human macrophage-like U937 cells to A549 cells. A549 cells were incubated with magnolol at 25 and 50 μmol/l. Then, 20 ng/ml TNF-α was used to activate the cells. Magnolol inhibited the growth of human pulmonary epithelial A549 cells in a dose- and time-dependent manner. Magnolol suppressed the adhesion of U937 cells to TNF-α-induced A549 cells. In cultured human pulmonary epithelial A549 cells, magnolol decreased TNF-α-induced upregulation of ICAM-1. Magnolol repressed TNF-α-induced activation of NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways in A549 cells by inhibiting phosphorylation of NF-κB, p38, extracellular signal-regulated kinase (ERK) 1/2, and stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK). These findings support the hypothesis that magnolol inhibits the inflammatory process in lung epithelial A549 cells by suppressing the ICAM-1 and NF-κB and MAPK signaling pathways. Taken together, these results indicate that magnolol offers significant potential as a therapeutic treatment for inflammatory diseases of the lungs including asthma, sepsis, and chronic obstructive pulmonary disease.

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

Genome-wide genetic analyses highlight mitogen-activated protein kinase (MAPK) signaling in the pathogenesis of endometriosis.

PubMed

Uimari, Outi; Rahmioglu, Nilufer; Nyholt, Dale R; Vincent, Katy; Missmer, Stacey A; Becker, Christian; Morris, Andrew P; Montgomery, Grant W; Zondervan, Krina T

2017-04-01

Do genome-wide association study (GWAS) data for endometriosis provide insight into novel biological pathways associated with its pathogenesis? GWAS analysis uncovered multiple pathways that are statistically enriched for genetic association signals, analysis of Stage A disease highlighted a novel variant in MAP3K4, while top pathways significantly associated with all endometriosis and Stage A disease included several mitogen-activated protein kinase (MAPK)-related pathways. Endometriosis is a complex disease with an estimated heritability of 50%. To date, GWAS revealed 10 genomic regions associated with endometriosis, explaining <4% of heritability, while half of the heritability is estimated to be due to common risk variants. Pathway analyses combine the evidence of single variants into gene-based measures, leveraging the aggregate effect of variants in genes and uncovering biological pathways involved in disease pathogenesis. Pathway analysis was conducted utilizing the International Endogene Consortium GWAS data, comprising 3194 surgically confirmed endometriosis cases and 7060 controls of European ancestry with genotype data imputed up to 1000 Genomes Phase three reference panel. GWAS was performed for all endometriosis cases and for Stage A (revised American Fertility Society (rAFS) I/II, n = 1686) and B (rAFS III/IV, n = 1364) cases separately. The identified significant pathways were compared with pathways previously investigated in the literature through candidate association studies. The most comprehensive biological pathway databases, MSigDB (including BioCarta, KEGG, PID, SA, SIG, ST and GO) and PANTHER were utilized to test for enrichment of genetic variants associated with endometriosis. Statistical enrichment analysis was performed using the MAGENTA (Meta-Analysis Gene-set Enrichment of variaNT Associations) software. The first genome-wide association analysis for Stage A endometriosis revealed a novel locus, rs144240142 (P = 6.45 × 10-8, OR = 1.71, 95% CI = 1.23-2.37), an intronic single-nucleotide polymorphism (SNP) within MAP3K4. This SNP was not associated with Stage B disease (P = 0.086). MAP3K4 was also shown to be differentially expressed in eutopic endometrium between Stage A endometriosis cases and controls (P = 3.8 × 10-4), but not with Stage B disease (P = 0.26). A total of 14 pathways enriched with genetic endometriosis associations were identified (false discovery rate (FDR)-P < 0.05). The pathways associated with any endometriosis were Grb2-Sos provides linkage to MAPK signaling for integrins pathway (P = 2.8 × 10-5, FDR-P = 3.0 × 10-3), Wnt signaling (P = 0.026, FDR-P = 0.026) and p130Cas linkage to MAPK signaling for integrins pathway (P = 6.0 × 10-4, FDR-P = 0.029); with Stage A endometriosis: extracellular signal-regulated kinase (ERK)1 ERK2 MAPK (P = 5.0 × 10-4, FDR-P = 5.0 × 10-4) and with Stage B endometriosis: two overlapping pathways that related to extracellular matrix biology-Core matrisome (P = 1.4 × 10-3, FDR-P = 0.013) and ECM glycoproteins (P = 1.8 × 10-3, FDR-P = 7.1 × 10-3). Genes arising from endometriosis candidate gene studies performed to date were enriched for Interleukin signaling pathway (P = 2.3 × 10-12), Apoptosis signaling pathway (P = 9.7 × 10-9) and Gonadotropin releasing hormone receptor pathway (P = 1.2 × 10-6); however, these pathways did not feature in the results based on GWAS data. Not applicable. The analysis is restricted to (i) variants in/near genes that can be assigned to pathways, excluding intergenic variants; (ii) the gene-based pathway definition as registered in the databases; (iii) women of European ancestry. The top ranked pathways associated with overall and Stage A endometriosis in particular involve integrin-mediated MAPK activation and intracellular ERK/MAPK acting downstream in the MAPK cascade, both acting in the control of cell division, gene expression, cell movement and survival. Other top enriched pathways in Stage B disease include ECM glycoprotein pathways important for extracellular structure and biochemical support. The results highlight the need for increased efforts to understand the functional role of these pathways in endometriosis pathogenesis, including the investigation of the biological effects of the genetic variants on downstream molecular processes in tissue relevant to endometriosis. Additionally, our results offer further support for the hypothesis of at least partially distinct causal pathophysiology for minimal/mild (rAFS I/II) vs. moderate/severe (rAFS III/IV) endometriosis. The genome-wide association data and Wellcome Trust Case Control Consortium (WTCCC) were generated through funding from the Wellcome Trust (WT084766/Z/08/Z, 076113 and 085475) and the National Health and Medical Research Council (NHMRC) of Australia (241944, 339462, 389927, 389875, 389891, 389892, 389938, 443036, 442915, 442981, 496610, 496739, 552485 and 552498). N.R. was funded by a grant from the Medical Research Council UK (MR/K011480/1). A.P.M. is a Wellcome Trust Senior Fellow in Basic Biomedical Science (grant WT098017). All authors declare there are no conflicts of interest. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology.

Genome-wide genetic analyses highlight mitogen-activated protein kinase (MAPK) signaling in the pathogenesis of endometriosis

PubMed Central

Uimari, Outi; Rahmioglu, Nilufer; Nyholt, Dale R.; Vincent, Katy; Missmer, Stacey A.; Becker, Christian; Morris, Andrew P.; Montgomery, Grant W.

2017-01-01

Abstract STUDY QUESTION Do genome-wide association study (GWAS) data for endometriosis provide insight into novel biological pathways associated with its pathogenesis? SUMMARY ANSWER GWAS analysis uncovered multiple pathways that are statistically enriched for genetic association signals, analysis of Stage A disease highlighted a novel variant in MAP3K4, while top pathways significantly associated with all endometriosis and Stage A disease included several mitogen-activated protein kinase (MAPK)-related pathways. WHAT IS KNOWN ALREADY Endometriosis is a complex disease with an estimated heritability of 50%. To date, GWAS revealed 10 genomic regions associated with endometriosis, explaining <4% of heritability, while half of the heritability is estimated to be due to common risk variants. Pathway analyses combine the evidence of single variants into gene-based measures, leveraging the aggregate effect of variants in genes and uncovering biological pathways involved in disease pathogenesis. STUDY DESIGN, SIZE, DURATION Pathway analysis was conducted utilizing the International Endogene Consortium GWAS data, comprising 3194 surgically confirmed endometriosis cases and 7060 controls of European ancestry with genotype data imputed up to 1000 Genomes Phase three reference panel. GWAS was performed for all endometriosis cases and for Stage A (revised American Fertility Society (rAFS) I/II, n = 1686) and B (rAFS III/IV, n = 1364) cases separately. The identified significant pathways were compared with pathways previously investigated in the literature through candidate association studies. PARTICIPANTS/MATERIALS, SETTING, METHODS The most comprehensive biological pathway databases, MSigDB (including BioCarta, KEGG, PID, SA, SIG, ST and GO) and PANTHER were utilized to test for enrichment of genetic variants associated with endometriosis. Statistical enrichment analysis was performed using the MAGENTA (Meta-Analysis Gene-set Enrichment of variaNT Associations) software. MAIN RESULTS AND THE ROLE OF CHANCE The first genome-wide association analysis for Stage A endometriosis revealed a novel locus, rs144240142 (P = 6.45 × 10−8, OR = 1.71, 95% CI = 1.23–2.37), an intronic single-nucleotide polymorphism (SNP) within MAP3K4. This SNP was not associated with Stage B disease (P = 0.086). MAP3K4 was also shown to be differentially expressed in eutopic endometrium between Stage A endometriosis cases and controls (P = 3.8 × 10−4), but not with Stage B disease (P = 0.26). A total of 14 pathways enriched with genetic endometriosis associations were identified (false discovery rate (FDR)-P < 0.05). The pathways associated with any endometriosis were Grb2-Sos provides linkage to MAPK signaling for integrins pathway (P = 2.8 × 10−5, FDR-P = 3.0 × 10−3), Wnt signaling (P = 0.026, FDR-P = 0.026) and p130Cas linkage to MAPK signaling for integrins pathway (P = 6.0 × 10−4, FDR-P = 0.029); with Stage A endometriosis: extracellular signal-regulated kinase (ERK)1 ERK2 MAPK (P = 5.0 × 10−4, FDR-P = 5.0 × 10−4) and with Stage B endometriosis: two overlapping pathways that related to extracellular matrix biology—Core matrisome (P = 1.4 × 10−3, FDR-P = 0.013) and ECM glycoproteins (P = 1.8 × 10−3, FDR-P = 7.1 × 10−3). Genes arising from endometriosis candidate gene studies performed to date were enriched for Interleukin signaling pathway (P = 2.3 × 10−12), Apoptosis signaling pathway (P = 9.7 × 10−9) and Gonadotropin releasing hormone receptor pathway (P = 1.2 × 10−6); however, these pathways did not feature in the results based on GWAS data. LARGE SCALE DATA Not applicable. LIMITATIONS, REASONS FOR CAUTION The analysis is restricted to (i) variants in/near genes that can be assigned to pathways, excluding intergenic variants; (ii) the gene-based pathway definition as registered in the databases; (iii) women of European ancestry. WIDER IMPLICATIONS OF THE FINDINGS The top ranked pathways associated with overall and Stage A endometriosis in particular involve integrin-mediated MAPK activation and intracellular ERK/MAPK acting downstream in the MAPK cascade, both acting in the control of cell division, gene expression, cell movement and survival. Other top enriched pathways in Stage B disease include ECM glycoprotein pathways important for extracellular structure and biochemical support. The results highlight the need for increased efforts to understand the functional role of these pathways in endometriosis pathogenesis, including the investigation of the biological effects of the genetic variants on downstream molecular processes in tissue relevant to endometriosis. Additionally, our results offer further support for the hypothesis of at least partially distinct causal pathophysiology for minimal/mild (rAFS I/II) vs. moderate/severe (rAFS III/IV) endometriosis. STUDY FUNDING/COMPETING INTEREST(S) The genome-wide association data and Wellcome Trust Case Control Consortium (WTCCC) were generated through funding from the Wellcome Trust (WT084766/Z/08/Z, 076113 and 085475) and the National Health and Medical Research Council (NHMRC) of Australia (241944, 339462, 389927, 389875, 389891, 389892, 389938, 443036, 442915, 442981, 496610, 496739, 552485 and 552498). N.R. was funded by a grant from the Medical Research Council UK (MR/K011480/1). A.P.M. is a Wellcome Trust Senior Fellow in Basic Biomedical Science (grant WT098017). All authors declare there are no conflicts of interest. PMID:28333195

p38 Mitogen-Activated Protein Kinase/Signal Transducer and Activator of Transcription-3 Pathway Signaling Regulates Expression of Inhibitory Molecules in T Cells Activated by HIV-1–Exposed Dendritic Cells

PubMed Central

Che, Karlhans Fru; Shankar, Esaki Muthu; Muthu, Sundaram; Zandi, Sasan; Sigvardsson, Mikael; Hinkula, Jorma; Messmer, Davorka; Larsson, Marie

2012-01-01

Human immunodeficiency virus type 1 (HIV-1) infection enhances the expression of inhibitory molecules on T cells, leading to T-cell impairment. The signaling pathways underlying the regulation of inhibitory molecules and subsequent onset of T-cell impairment remain elusive. We showed that both autologous and allogeneic T cells exposed to HIV-pulsed dendritic cells (DCs) upregulated cytotoxic T-lymphocyte antigen (CTLA-4), tumor-necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), lymphocyte-activation gene-3 (LAG3), T-cell immunoglobulin mucin-3 (TIM-3), CD160 and certain suppression-associated transcription factors, such as B-lymphocyte induced maturation protein-1 (BLIMP-1), deltex homolog 1 protein (DTX1) and forkhead box P3 (FOXP3), leading to T-cell suppression. This induction was regulated by p38 mitogen-activated protein kinase/signal transducer and activator of transcription-3 (P38MAPK/STAT3) pathways, because their blockade significantly abrogated expression of all the inhibitory molecules studied and a subsequent recovery in T-cell proliferation. Neither interleukin-6 (IL-6) nor IL-10 nor growth factors known to activate STAT3 signaling events were responsible for STAT3 activation. Involvement of the P38MAPK/STAT3 pathways was evident because these proteins had a higher level of phosphorylation in the HIV-1–primed cells. Furthermore, blockade of viral CD4 binding and fusion significantly reduced the negative effects DCs imposed on primed T cells. In conclusion, HIV-1 interaction with DCs modulated their functionality, causing them to trigger the activation of the P38MAPK/STAT3 pathway in T cells, which was responsible for the upregulation of inhibitory molecules. PMID:22777388

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

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

PubMed Central

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

2011-01-01

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

Triiodothyronine promotes the proliferation of epicardial progenitor cells through the MAPK/ERK pathway.

PubMed

Deng, Song-Bai; Jing, Xiao-Dong; Wei, Xiao-Ming; Du, Jian-Lin; Liu, Ya-Jie; Qin, Qin; She, Qiang

2017-04-29

Thyroid hormone has important functions in the development and physiological function of the heart. The aim of this study was to determine whether 3,5,3'-Triiodothyronine (T3) can promote the proliferation of epicardial progenitor cells (EPCs) and to investigate the potential underlying mechanism. Our results showed that T3 significantly promoted the proliferation of EPCs in a concentration- and time-dependent manner. The thyroid hormone nuclear receptor inhibitor bisphenol A (100 μmol/L) did not affect T3's ability to induce proliferation. Further studies showed that the mRNA expression levels of mitogen-activated protein kinase 1 (MAPK1), MAPK3, and Ki67 in EPCs in the T3 group (10 nmol/L) increased 2.9-, 3-, and 4.1-fold, respectively, compared with those in the control group (P < 0.05). In addition, the mRNA expression of the cell cycle protein cyclin D1 in the T3 group increased approximately 2-fold compared with the control group (P < 0.05), and there were more EPCs in the S phase of the cell cycle (20.6% vs. 12.0%, P < 0.05). The mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway inhibitor U0126 (10 μmol/L) significantly inhibited the ability of T3 to promote the proliferation of EPCs and to alter cell cycle progression. This study suggested that T3 significantly promotes the proliferation of EPCs, and this effect may be achieved through activation of the MAPK/ERK signaling pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

Sensitivity of GBM cells to cAMP agonist-mediated apoptosis correlates with CD44 expression and agonist resistance with MAPK signaling.

PubMed

Daniel, Paul M; Filiz, Gulay; Mantamadiotis, Theo

2016-12-01

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.

Anti-cancer effects of CME-1, a novel polysaccharide, purified from the mycelia of Cordyceps sinensis against B16-F10 melanoma cells.

PubMed

Jayakumar, Thanasekaran; Chiu, Chong-Chi; Wang, Shwu-Huey; Chou, Duen-Suey; Huang, Yung-Kai; Sheu, Joen-Rong

2014-01-01

Matrix metalloproteinases (MMPs) play important roles in the invasion and migration of cancer cells. In melanoma, several signaling pathways are constitutively activated. Among these, the mitogen-activated protein kinase (MAPKs) signaling pathways are activated through multiple signal transduction molecules and appear to play major roles in melanoma progression. Therefore, the inhibition of MAPK signaling might be a crucial role for the treatment of melanoma cancer. We examined the anticancer effect of CME-1, a novel water-soluble polysaccharide fraction, isolated from Cordyceps sinensis mycelia on B16-F10 melanoma cells. B16-F10 cells were exposed to different concentrations of CME-1 (250, 500 and 800 μg/ml) for 24 h in 5% CO² incubator at 37°C. Western blot analysis was performed to detect the expression of MMP-1, p-p38 MAPK, p-ERK1/2, and IkB-α in B16-F10 cells. Cell migration test was performed by wound healing migration assay. CME-1 suppresses cell migration in a concentration-dependent manner. Western blotting analysis revealed that CME-1 led to the reduction on the expression levels of MMP-1 and down regulated the expression of phosphorylated extracellular signal-regulated kinase (ERK1/2 and p38 mitogen-activated protein kinase (p38 MAPK). CME-1 restored the IkB-degradation in B16F10 cells. These results indicate that CME-1 inhibited MMP-1 expressions in B16F10 melanoma cells through either NF-kB or ERK/p38 MAPK down regulation thereby inhibiting B16F10 cell migration. Therefore, we proposed that CME-1 might be developed as a therapeutic potential candidate for the treatment of cancer metastasis.

An Inhibitory Role of Osthole in Rat MSCs Osteogenic Differentiation and Proliferation via Wnt/β-Catenin and Erk1/2-MAPK Pathways.

PubMed

Hu, Hongyang; Chen, Min; Dai, Guangzu; Du, Guoqing; Wang, Xuezong; He, Jie; Zhao, Yongfang; Han, Dapeng; Cao, Yuelong; Zheng, Yuxin; Ding, Daofang

2016-01-01

Bone marrow-derived mesenchymal stem cells (MSCs) are responsible for new bone formation during adulthood. Accumulating evidences showed that Osthole promotes the osteogenic differentiation in primary osteoblasts. The aim of this study was to investigate whether Osthole exhibits a potential to stimulate the osteogenic differentiation of MSCs and the underlying mechanism. MSCs were treated with a gradient concentration of Osthole (6.25 µM, 12.5 µM, and 25 µM). Cell proliferation was assessed by western blotting with the proliferating cell nuclear antigen (PCNA) and Cyclin D1 antibodies, fluorescence activated cell sorting (FACS), and cell counting kit 8 (CCK8). MSCs were cultured in osteogenesis-induced medium for one or two weeks. The osteogenic differentiation of MSCs was estimated by Alkaline Phosphatase (ALP) staining, Alizarin red staining, Calcium influx, and quantitative PCR (qPCR). The underlying mechanism of Osthole-induced osteogenesis was further evaluated by western blotting with antibodies in Wnt/β-catenin, PI3K/Akt, BMPs/smad1/5/8, and MAPK signaling pathways. Osthole inhibited proliferation of rat MSCs in a dose-dependent manner. Osthole suppressed osteogenic differentiation of rat MSCs by down-regulating the activities of Wnt/β-catenin and Erk1/2-MAPK signaling. Osthole inhibits the proliferation and osteogenic differentiation of rat MSCs, which might be mediated through blocking the Wnt/β-catenin and Erk1/2-MAPK signaling pathways. © 2016 The Author(s) Published by S. Karger AG, Basel.

ROS generation and MAPKs activation contribute to the Ni-induced testosterone synthesis disturbance in rat Leydig cells.

PubMed

Han, Aijie; Zou, Lingyue; Gan, Xiaoqin; Li, Yu; Liu, Fangfang; Chang, Xuhong; Zhang, Xiaotian; Tian, Minmin; Li, Sheng; Su, Li; Sun, Yingbiao

2018-06-15

Nickel (Ni) can disorder testosterone synthesis in rat Leydig cells, whereas the mechanisms remain unclear. The aim of this study was to investigate the role of reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) in Ni-induced disturbance of testosterone synthesis in rat Leydig cells. The testosterone production and ROS levels were detected in Leydig cells. The mRNA and protein levels of testosterone synthetase, including StAR, CYP11A1, 3β-HSD, CYP17A1 and 17β-HSD, were determined. Effects of Ni on the ERK1/2, p38 and JNK MAPKs were also investigated. The results showed that Ni triggered ROS generation, consequently resulted in the decrease of testosterone synthetase expression and testosterone production in Leydig cells, which were then attenuated by ROS scavengers of N-acetylcysteine (NAC) and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), indicating that ROS are involved in the Ni-induced testosterone biosynthesis disturbance. Meanwhile Ni activated the ERK1/2, p38 and JNK MAPKs. Furthermore, Ni-inhibited testosterone synthetase expression levels and testosterone secretion were all alleviated by co-treatment with MAPK specific inhibitors (U0126 and SB203580, respectively), implying that Ni inhibited testosterone synthesis through activating ERK1/2 and p38 MAPK signal pathways in Leydig cells. In conclusion, these findings suggest that Ni causes testosterone synthesis disorder, partly, via ROS and MAPK signal pathways. Copyright © 2018 Elsevier B.V. All rights reserved.

Rewiring MAP kinases in Saccharomyces cerevisiae to regulate novel targets through ubiquitination.

PubMed

Groves, Benjamin; Khakhar, Arjun; Nadel, Cory M; Gardner, Richard G; Seelig, Georg

2016-08-15

Evolution has often copied and repurposed the mitogen-activated protein kinase (MAPK) signaling module. Understanding how connections form during evolution, in disease and across individuals requires knowledge of the basic tenets that govern kinase-substrate interactions. We identify criteria sufficient for establishing regulatory links between a MAPK and a non-native substrate. The yeast MAPK Fus3 and human MAPK ERK2 can be functionally redirected if only two conditions are met: the kinase and substrate contain matching interaction domains and the substrate includes a phospho-motif that can be phosphorylated by the kinase and recruit a downstream effector. We used a panel of interaction domains and phosphorylation-activated degradation motifs to demonstrate modular and scalable retargeting. We applied our approach to reshape the signaling behavior of an existing kinase pathway. Together, our results demonstrate that a MAPK can be largely defined by its interaction domains and compatible phospho-motifs and provide insight into how MAPK-substrate connections form.

Fisetin, a dietary phytochemical, overcomes Erlotinib-resistance of lung adenocarcinoma cells through inhibition of MAPK and AKT pathways.

PubMed

Zhang, Liang; Huang, Yi; Zhuo, Wenlei; Zhu, Yi; Zhu, Bo; Chen, Zhengtang

2016-01-01

Erlotinib (Tarceva) is a selective epidermal growth factor receptor tyrosine kinase inhibitor for treatment of non-small cell lung cancer (NSCLC). However, its efficacy is usually reduced by the occurrence of drug resistance. Our recent study showed that a flavonoid found in many plants, Fisetin, might have a potential to reverse the acquired Cisplatin-resistance of lung adenocarcinoma. In the present study, we aimed to test whether Fisetin could have the ability to reverse Erlotinib-resistance of lung cancer cells. Erlotinib-resistant lung adenocarcinoma cells, HCC827-ER, were cultured from the cell line HCC827, and the effects of Fisetin and Erlotinib on the cell viability and apoptosis were evaluated. The possible signaling pathways in this process were also detected. As expected, the results showed that Fisetin effectively increased sensitivity of Erlotinib-resistant lung cancer cells to Erlotinib, possibly by inhibiting aberrant activation of MAPK and AKT signaling pathways resulted from AXL suppression. In conclusion, Fisetin was a potential agent for reversing acquired Erlotinib-resistance of lung adenocarcinoma. Inactivation of AXL, MAPK and AKT pathways might play a partial role in this process.

Fisetin, a dietary phytochemical, overcomes Erlotinib-resistance of lung adenocarcinoma cells through inhibition of MAPK and AKT pathways

PubMed Central

Zhang, Liang; Huang, Yi; Zhuo, Wenlei; Zhu, Yi; Zhu, Bo; Chen, Zhengtang

2016-01-01

Erlotinib (Tarceva) is a selective epidermal growth factor receptor tyrosine kinase inhibitor for treatment of non-small cell lung cancer (NSCLC). However, its efficacy is usually reduced by the occurrence of drug resistance. Our recent study showed that a flavonoid found in many plants, Fisetin, might have a potential to reverse the acquired Cisplatin-resistance of lung adenocarcinoma. In the present study, we aimed to test whether Fisetin could have the ability to reverse Erlotinib-resistance of lung cancer cells. Erlotinib-resistant lung adenocarcinoma cells, HCC827-ER, were cultured from the cell line HCC827, and the effects of Fisetin and Erlotinib on the cell viability and apoptosis were evaluated. The possible signaling pathways in this process were also detected. As expected, the results showed that Fisetin effectively increased sensitivity of Erlotinib-resistant lung cancer cells to Erlotinib, possibly by inhibiting aberrant activation of MAPK and AKT signaling pathways resulted from AXL suppression. In conclusion, Fisetin was a potential agent for reversing acquired Erlotinib-resistance of lung adenocarcinoma. Inactivation of AXL, MAPK and AKT pathways might play a partial role in this process. PMID:27904686

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

PubMed

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

2002-09-15

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

Mitogen-activated protein kinase phosphatase 1 (MKP-1) in macrophage biology and cardiovascular disease. A redox-regulated master controller of monocyte function and macrophage phenotype.

PubMed

Kim, Hong Seok; Asmis, Reto

2017-08-01

MAPK pathways play a critical role in the activation of monocytes and macrophages by pathogens, signaling molecules and environmental cues and in the regulation of macrophage function and plasticity. MAPK phosphatase 1 (MKP-1) has emerged as the main counter-regulator of MAPK signaling in monocytes and macrophages. Loss of MKP-1 in monocytes and macrophages in response to metabolic stress leads to dysregulation of monocyte adhesion and migration, and gives rise to dysfunctional, proatherogenic monocyte-derived macrophages. Here we review the properties of this redox-regulated dual-specificity MAPK phosphatase and the role of MKP-1 in monocyte and macrophage biology and cardiovascular diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

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

PubMed Central

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

2001-01-01

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

IL-17A causes depression-like symptoms via NFκB and p38MAPK signaling pathways in mice: Implications for psoriasis associated depression.

PubMed

Nadeem, Ahmed; Ahmad, Sheikh F; Al-Harbi, Naif O; Fardan, Ali S; El-Sherbeeny, Ahmed M; Ibrahim, Khalid E; Attia, Sabry M

2017-09-01

Psoriasis has been shown to be associated with an increased prevalence of comorbid major depression. IL-17A plays an important role in both depression and psoriasis. IL-17A has been shown to be elevated in systemic circulation of psoriatic patients. IL-17A released from different immune cells during psoriasis may be responsible for the development of neuropsychiatric symptoms associated with depression. Therefore, this study explored the association of systemic IL-17A with depression. The present study utilized imiquimod model of psoriatic inflammation as well as IL-17A administration in mice to investigate the effect of IL-17A on depression-like behavior. Psoriatic inflammation led to enhanced IL-17A expression in peripheral immune cells of both innate and adaptive origin. This was associated with increased NFκB/p38MAPK signaling and inflammatory mediators in different brain regions, and depression-like symptoms (as reflected by sucrose preference and tail suspension tests). The role of IL-17A was further confirmed by administering it alone for ten days, followed by assessment of the same parameters. IL-17A administration produced effects similar to psoriasis-like inflammation on neurobehavior and NFκB/p38MAPK pathways. Moreover, both NFκB and p38MAPK inhibitors led to attenuation in IL-17A associated with depression-like behavior via reduction in inflammatory mediators, such as MCP-1, iNOS, IL-6, and CXCL-2. Furthermore, anti-IL17A antibody also led to a reduction in imiquimod-induced depression-like symptoms, as well as NFκB/p38MAPK signaling. The present study shows that IL-17A plays an important role in comorbid depression associated with psoriatic inflammation, where both NFκB and p38MAPK pathways play significant roles via upregulation of inflammatory mediators in the brain. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of microRNA-129 and its target gene c-Fos on proliferation and apoptosis of hippocampal neurons in rats with epilepsy via the MAPK signaling pathway.

PubMed

Wu, Dong-Mei; Zhang, Yu-Tong; Lu, Jun; Zheng, Yuan-Lin

2018-09-01

This study aims to investigate the effect of microRNA-129 (miR-129) on proliferation and apoptosis of hippocampal neurons in epilepsy rats by targeting c-Fos via the MAPK signaling pathway. Thirty rats were equally classified into a model group (successfully established as chronic epilepsy models) and a normal group. Expression of miR-129, c-Fos, bax, and MAPK was detected by RT-qPCR and Western blotting. Hippocampal neurons were assigned into normal, blank, negative control (NC), miR-129 mimic, miR-129 inhibitor, siRNA-c-Fos, miR-129 inhibitor+siRNA-c-Fos groups. The targeting relationship between miR-129 and c-Fos was predicted and verified by bioinformatics websites and dual-luciferase reporter gene assay. Cell proliferation after transfection was measured by MTT assay, and cell cycle and apoptosis by flow cytometry. c-Fos is a potential target gene of miR-129. Compared with the normal group, the other six groups showed a decreased miR-129 expression; increased expression of expression of c-Fos, Bax, and MAPK; decreased proliferation; accelerated apoptosis; more cells arrested in the G1 phase; and fewer cells arrested in the S phase. Compared with the blank and NC groups, the miR-129 mimic group and the siRNA-c-Fos group showed decreased expression of c-Fos, Bax, and MAPK, increased cells proliferation, and decreased cell apoptosis, fewer cells arrested in the G1 phase and more cells arrested in the S phase. However, the miR-129 inhibitor groups showed reverse consequences. This study suggests that miR-129 could inhibit the occurrence and development of epilepsy by repressing c-Fos expression through inhibiting the MAPK signaling pathway. © 2017 Wiley Periodicals, Inc.

Integrated analysis of miRNA and mRNA expression data identifies multiple miRNAs regulatory networks for the tumorigenesis of colorectal cancer.

PubMed

Xu, Peng; Wang, Junhua; Sun, Bo; Xiao, Zhongdang

2018-06-15

Investigating the potential biological function of differential changed genes through integrating multiple omics data including miRNA and mRNA expression profiles, is always hot topic. However, how to evaluate the repression effect on target genes integrating miRNA and mRNA expression profiles are not fully solved. In this study, we provide an analyzing method by integrating both miRNAs and mRNAs expression data simultaneously. Difference analysis was adopted based on the repression score, then significantly repressed mRNAs were screened out by DEGseq. Pathway analysis for the significantly repressed mRNAs shows that multiple pathways such as MAPK signaling pathway, TGF-beta signaling pathway and so on, may correlated to the colorectal cancer(CRC). Focusing on the MAPK signaling pathway, a miRNA-mRNA network that centering the cell fate genes was constructed. Finally, the miRNA-mRNAs that potentially important in the CRC carcinogenesis were screened out and scored by impact index. Copyright © 2018 Elsevier B.V. All rights reserved.

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

PubMed Central

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

2011-01-01

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

Absence of suppressor of cytokine signalling 3 reduces self-renewal and promotes differentiation in murine embryonic stem cells.

PubMed

Forrai, Ariel; Boyle, Kristy; Hart, Adam H; Hartley, Lynne; Rakar, Steven; Willson, Tracy A; Simpson, Ken M; Roberts, Andrew W; Alexander, Warren S; Voss, Anne K; Robb, Lorraine

2006-03-01

Leukemia inhibitory factor (LIF) is required to maintain pluripotency and permit self-renewal of murine embryonic stem (ES) cells. LIF binds to a receptor complex of LIFR-beta and gp130 and signals via the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway, with signalling attenuated by suppressor of cytokine signalling (SOCS) proteins. Recent in vivo studies have highlighted the role of SOCS-3 in the negative regulation of signalling via gp130. To determine the role of SOCS-3 in ES cell biology, SOCS-3-null ES cell lines were generated. When cultured in LIF levels that sustain self-renewal of wild-type cells, SOCS-3-null ES cell lines exhibited less self-renewal and greater differentiation into primitive endoderm. The absence of SOCS-3 enhanced JAK-STAT and extracellular signal-related kinase 1/2 (ERK-1/2)-mitogen-activated protein kinase (MAPK) signal transduction via gp130, with higher levels of phosphorylated STAT-1, STAT-3, SH-2 domain-containing cytoplasmic protein tyrosine phosphatase 2 (SHP-2), and ERK-1/2 in steady state and in response to LIF stimulation. Attenuation of ERK signalling by the addition of MAPK/ERK kinase (MEK) inhibitors to SOCS-3-null ES cell cultures rescued the differentiation phenotype, but did not restore proliferation to wild-type levels. In summary, SOCS-3 plays a crucial role in the regulation of the LIF signalling pathway in murine ES cells. Its absence perturbs the balance between activation of the JAK-STAT and SHP-2-ERK-1/2-MAPK pathways, resulting in less self-renewal and a greater potential for differentiation into the primitive endoderm lineage.

Low-Dose Radiation Induces Cell Proliferation in Human Embryonic Lung Fibroblasts but not in Lung Cancer Cells: Importance of ERK1/2 and AKT Signaling Pathways.

PubMed

Liang, Xinyue; Gu, Junlian; Yu, Dehai; Wang, Guanjun; Zhou, Lei; Zhang, Xiaoying; Zhao, Yuguang; Chen, Xiao; Zheng, Shirong; Liu, Qiang; Cai, Lu; Cui, Jiuwei; Li, Wei

2016-01-01

Hormesis and adaptive responses are 2 important biological effects of low-dose ionizing radiation (LDR). In normal tissue, LDR induces hormesis as evinced by increased cell proliferation; however, whether LDR also increases tumor cell proliferation needs to be investigated. In this study, cell proliferation was assayed by total cell numbers and the Cell Counting Kit 8 assay. Mitogen-activated protein kinases (MAPK)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3' -kinase(PI3K)-Akt (PI3K/AKT) phosphorylation were determined by Western blot analysis. Human embryonic lung fibroblast 2BS and lung cancer NCI-H446 cell lines were irradiated with LDR at different doses (20-100 mGy). In response to 20 to 75 mGy X-rays, cell proliferation was significantly increased in 2BS but not in NCI-H446 cells. In 2BS cells, LDR at 20 to 75 mGy also stimulated phosphorylation of MAPK/ERK pathway proteins including ERK, MEK, and Raf and of the PI3K/AKT pathway protein AKT. To test whether ERK1/2 and AKT pathway activation was involved in the stimulation of cell proliferation in 2BS cells, the MAPK/ERK and PI3K/AKT pathways were inhibited using their specific inhibitors, U0126 and LY294002. U0126 decreased the phosphorylation of ERK1/2, and LY294002 decreased the phosphorylation of AKT; each could significantly inhibit LDR-induced 2BS cell proliferation. However, LDR did not stimulate these kinases, and kinase inhibitors also did not affect cell proliferation in the NCI-H446 cells. These results suggest that LDR stimulates cell proliferation via the activation of both MAPK/ERK and PI3K/AKT signaling pathways in 2BS but not in NCI-H446 cells. This finding implies the potential for applying LDR to protect normal tissues from radiotherapy without diminishing the efficacy of tumor therapy.

Defocused low-energy shock wave activates adipose tissue-derived stem cells in vitro via multiple signaling pathways.

PubMed

Xu, Lina; Zhao, Yong; Wang, Muwen; Song, Wei; Li, Bo; Liu, Wei; Jin, Xunbo; Zhang, Haiyang

2016-12-01

We found defocused low-energy shock wave (DLSW) could be applied in regenerative medicine by activating mesenchymal stromal cells. However, the possible signaling pathways that participated in this process remain unknown. In the present study, DLSW was applied in cultured rat adipose tissue-derived stem cells (ADSCs) to explore its effect on ADSCs and the activated signaling pathways. After treating with DLSW, the cellular morphology and cytoskeleton of ADSCs were observed. The secretions of ADSCs were detected. The expressions of ADSC surface antigens were analyzed using flow cytometry. The expressions of proliferating cell nuclear antigen and Ki67 were analyzed using western blot. The expression of CXCR2 and the migrations of ADSCs in vitro and in vivo were detected. The phosphorylation of selected signaling pathways with or without inhibitors was also detected. DLSW did not change the morphology and phenotype of ADSCs, and could promote the secretion, proliferation and migration of ADSCs. The phosphorylation levels were significantly higher in mitogen-activated protein kinases (MAPK) pathway, phosphoinositide 3-kinase (PI-3K)/AKT pathway and nuclear factor-kappa B (NF-κB) signaling pathway but not in Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. Furthermore, ADSCs were not activated by DLSW after adding the inhibitors of these pathways simultaneously. Our results demonstrated for the first time that DLSW could activate ADSCs through MAPK, PI-3K/AKT and NF-κB signaling pathways. Combination of DLSW and agonists targeting these pathways might improve the efficacy of ADSCs in regenerative medicine in the future. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

[Effects of UO-126 on proliferation and fbw7 expression of HeLa cells].

PubMed

Sun, Di; Shen, Yi; Wang, Shao-hua; Xiang, Zi-wu; Xie, Ying-shan; Jiang, Xin

2010-02-01

To observe the effects of UO-126 on the expression of F-box and WD repeat domain-containing protein 7(FBW7)and on the proliferation of human cervical cancer cell lines (HeLa cells). HeLa cells were treated with different concentrations of UO-126, MTT assay was used to observe the proliferation of HeLa cells. Immunofluorescence showed the location and expression of FBW7 in HeLa cells. The mRNA and protein expression of FBW7 were detected by RT-PCR and Western blot before and after mitogen-activated protein kinases (MAPK)signal was blocked by UO-126 a MAPK inhibitor. MTT results showed that the concentration range of MAPK signaling pathway inhibitor UO-126 inhibited the proliferation of HeLa cells in a concentration-and time-dependent manner(P<0.05). Immunofluorescence showed that the expression of positive FBW7 had increased after HeLa cells were treated with UO-126. RT-PCR and Western blot exhibited that the FBW7 mRNA and protein expression had significantly increased before and after HeLa cells were treated with UO-126(P<0.05). UO-126 could inhibit HeLa cells proliferation, FBW7 lied downstream of MAPK signaling pathway.

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

PubMed

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

2017-11-06

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

Ceramide-Induced Apoptosis in Renal Tubular Cells: A Role of Mitochondria and Sphingosine-1-Phoshate

PubMed Central

Ueda, Norishi

2015-01-01

Ceramide is synthesized upon stimuli, and induces apoptosis in renal tubular cells (RTCs). Sphingosine-1 phosphate (S1P) functions as a survival factor. Thus, the balance of ceramide/S1P determines ceramide-induced apoptosis. Mitochondria play a key role for ceramide-induced apoptosis by altered mitochondrial outer membrane permeability (MOMP). Ceramide enhances oligomerization of pro-apoptotic Bcl-2 family proteins, ceramide channel, and reduces anti-apoptotic Bcl-2 proteins in the MOM. This process alters MOMP, resulting in generation of reactive oxygen species (ROS), cytochrome C release into the cytosol, caspase activation, and apoptosis. Ceramide regulates apoptosis through mitogen-activated protein kinases (MAPKs)-dependent and -independent pathways. Conversely, MAPKs alter ceramide generation by regulating the enzymes involving ceramide metabolism, affecting ceramide-induced apoptosis. Crosstalk between Bcl-2 family proteins, ROS, and many signaling pathways regulates ceramide-induced apoptosis. Growth factors rescue ceramide-induced apoptosis by regulating the enzymes involving ceramide metabolism, S1P, and signaling pathways including MAPKs. This article reviews evidence supporting a role of ceramide for apoptosis and discusses a role of mitochondria, including MOMP, Bcl-2 family proteins, ROS, and signaling pathways, and crosstalk between these factors in the regulation of ceramide-induced apoptosis of RTCs. A balancing role between ceramide and S1P and the strategy for preventing ceramide-induced apoptosis by growth factors are also discussed. PMID:25751724

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

PubMed Central

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

2015-01-01

The α1A-AR is thought to couple predominantly to the Gαq/PLC pathway and lead to phosphoinositide hydrolysis and calcium mobilization, although certain agonists acting at this receptor have been reported to trigger activation of arachidonic acid formation and MAPK pathways. For several G protein-coupled receptors (GPCRs) agonists can manifest a bias for activation of particular effector signaling output, i.e. not all agonists of a given GPCR generate responses through utilization of the same signaling cascade(s). Previous work with Gαq coupling-defective variants of α1A-AR, as well as a combination of Ca2+ channel blockers, uncovered cross-talk between α1A-AR and β2-AR that leads to potentiation of a Gαq-independent signaling cascade in response to α1A-AR activation. We hypothesized that molecules exist that act as biased agonists to selectively activate this pathway. In this report, isoproterenol (Iso), typically viewed as β-AR-selective agonist, was examined with respect to activation of α1A-AR. α1A-AR selective antagonists were used to specifically block Iso evoked signaling in different cellular backgrounds and confirm its action at α1A-AR. Iso induced signaling at α1A-AR was further interrogated by probing steps along the Gαq /PLC, Gαs and MAPK/ERK pathways. In HEK-293/EBNA cells transiently transduced with α1A-AR, and CHO_α1A-AR stable cells, Iso evoked low potency ERK activity as well as Ca2+ mobilization that could be blocked by α1A-AR selective antagonists. The kinetics of Iso induced Ca2+ transients differed from typical Gαq- mediated Ca2+ mobilization, lacking both the fast IP3R mediated response and the sustained phase of Ca2+ re-entry. Moreover, no inositol phosphate (IP) accumulation could be detected in either cell line after stimulation with Iso, but activation was accompanied by receptor internalization. Data are presented that indicate that Iso represents a novel type of α1A-AR partial agonist with signaling bias toward MAPK/ERK signaling cascade that is likely independent of coupling to Gαq. PMID:25606852

Dexras1 links glucocorticoids to insulin-like growth factor-1 signaling in adipogenesis

PubMed Central

Kim, Hyo Jung; Cha, Jiyoung Y.; Seok, Jo Woon; Choi, Yoonjeong; Yoon, Bo Kyung; Choi, Hyeonjin; Yu, Jung Hwan; Song, Su Jin; Kim, Ara; Lee, Hyemin; Kim, Daeun; Han, Ji Yoon; Kim, Jae-woo

2016-01-01

Glucocorticoids are associated with obesity, but the underlying mechanism by which they function remains poorly understood. Previously, we showed that small G protein Dexras1 is expressed by glucocorticoids and leads to adipocyte differentiation. In this study, we explored the mechanism by which Dexras1 mediates adipogenesis and show a link to the insulin-like growth factor-1 (IGF-1) signaling pathway. Without Dexras1, the activation of MAPK and subsequent phosphorylation of CCAAT/enhancer binding protein β (C/EBPβ) is abolished, thereby inhibiting mitotic clonal expansion and further adipocyte differentiation. Dexras1 translocates to the plasma membrane upon insulin or IGF-1 treatment, for which the unique C-terminal domain (amino acids 223–276) is essential. Dexras1-dependent MAPK activation is selectively involved in the IGF-1 signaling, because another Ras protein, H-ras localized to the plasma membrane independently of insulin treatment. Moreover, neither epidermal growth factor nor other cell types shows Dexras1-dependent MAPK activation, indicating the importance of Dexras1 in IGF-1 signaling in adipogenesis. Dexras1 interacts with Shc and Raf, indicating that Dexras1-induced activation of MAPK is largely dependent on the Shc-Grb2-Raf complex. These results suggest that Dexras1 is a critical mediator of the IGF-1 signal to activate MAPK, linking glucocorticoid signaling to IGF-1 signaling in adipogenesis. PMID:27345868

17beta-estradiol promotes the odonto/osteogenic differentiation of stem cells from apical papilla via mitogen-activated protein kinase pathway.

PubMed

Li, Yao; Yan, Ming; Wang, Zilu; Zheng, Yangyu; Li, Junjun; Ma, Shu; Liu, Genxia; Yu, Jinhua

2014-11-17

Estrogen plays an important role in the osteogenic differentiation of mesenchymal stem cells, while stem cells from apical papilla (SCAP) can contribute to the formation of dentin/bone-like tissues. To date, the effects of estrogen on the differentiation of SCAP remain unclear. SCAP was isolated and treated with 10⁻⁷ M 17beta-estradiol (E2). The odonto/osteogenic potency and the involvement of mitogen-activated protein kinase (MAPK) signaling pathway were subsequently investigated by using methyl-thiazolyl-tetrazolium (MTT) assay, and other methods. MTT and flow cytometry results demonstrated that E2 treatment had no effect on the proliferation of SCAP in vitro, while alkaline phosphatase (ALP) assay and alizarin red staining showed that E2 can significantly promote ALP activity and mineralization ability in SCAP. Real-time reverse transcription polymerase chain reaction (RT-PCR) and western blot assay revealed that the odonto/osteogenic markers (ALP, DMP1/DMP1, DSPP/DSP, RUNX2/RUNX2, OSX/OSX and OCN/OCN) were significantly upregulated in E2-treated SCAP. In addition, the expression of phosphor-p38 and phosphor-JNK in these stem cells was enhanced by E2 treatment, as was the expression of the nuclear downstream transcription factors including phosphor-Sp1, phosphor-Elk-1, phosphor-c-Jun and phosphor-c-Fos, indicating the activation of MAPK signaling pathway during the odonto/osteogenic differentiation of E2-treated SCAP. Conversely, the differentiation of E2-treated SCAP was inhibited in the presence of MAPK specific inhibitors. The ondonto/osteogenic differentiation of SCAP is enhanced by 10⁻⁷ M 17beta-estradiol via the activation of MAPK signaling pathway.

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

PubMed

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

2015-01-01

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

Intracellular Networks of the PI3K/AKT and MAPK Pathways for Regulating Toxoplasma gondii-Induced IL-23 and IL-12 Production in Human THP-1 Cells

PubMed Central

Choi, In-Wook; Ismail, Hassan Ahmed Hassan Ahmed; Zhou, Wei; Cha, Guang-Ho; Zhou, Yu; Yuk, Jae-Min; Jo, Eun-Kyeong; Lee, Young-Ha

2015-01-01

Interleukin (IL)-23 and IL-12 are closely related in structure, and these cytokines regulate both innate and adaptive immunity. However, the precise signaling networks that regulate the production of each in Toxoplasma gondii-infected THP-1 monocytic cells, particularly the PI3K/AKT and MAPK signaling pathways, remain unknown. In the present study, T. gondii infection upregulated the expression of IL-23 and IL-12 in THP-1 cells, and both cytokines increased with parasite dose. IL-23 secretion was strongly inhibited by TLR2 monoclonal antibody (mAb) treatment in a dose-dependent manner and by TLR2 siRNA transfection, whereas IL-12 secretion was strongly inhibited by TLR4 mAb treatment dose-dependently and by TLR4 siRNA transfection. IL-23 production was dose-dependently inhibited by the PI3K inhibitors LY294002 and wortmannin, whereas IL-12 production increased dose-dependently. THP-1 cells exposed to live T. gondii tachyzoites underwent rapid p38 MAPK, ERK1/2 and JNK activation. IL-23 production was significantly upregulated by the p38 MAPK inhibitor SB203580 dose-dependently, whereas pretreatment with 10 μM SB203580 significantly downregulated IL-12 production. ERK1/2 inhibition by PD98059 was significantly downregulated IL-23 production but upregulated IL-12 production. JNK inhibition by SP600125 upregulated IL-23 production, but IL-12 production was significantly downregulated dose-dependently. T. gondii infection resulted in AKT activation, and AKT phosphorylation was inhibited dose-dependently after pretreatment with PI3K inhibitors. In T. gondii-infected THP-1 cells, ERK1/2 activation was regulated by PI3K; however, the phosphorylation of p38 MAPK and JNK was negatively modulated by the PI3K signaling pathway. Collectively, these results indicate that IL-23 production in T. gondii-infected THP-1 cells was regulated mainly by TLR2 and then by PI3K and ERK1/2; however, IL-12 production was mainly regulated by TLR4 and then by p38 MAPK and JNK. Our findings provide new insight concerning the intracellular networks of the PI3K/AKT and MAPK signaling cascades for regulating T. gondii-induced IL-23 and IL-12 secretion in human monocytic cells. PMID:26528819

Integration of Golgi trafficking and growth factor signaling by the lipid phosphatase SAC1

PubMed Central

Blagoveshchenskaya, Anastasia; Cheong, Fei Ying; Rohde, Holger M.; Glover, Greta; Knödler, Andreas; Nicolson, Teresa; Boehmelt, Guido; Mayinger, Peter

2008-01-01

When a growing cell expands, lipids and proteins must be delivered to its periphery. Although this phenomenon has been observed for decades, it remains unknown how the secretory pathway responds to growth signaling. We demonstrate that control of Golgi phosphatidylinositol-4-phosphate (PI(4)P) is required for growth-dependent secretion. The phosphoinositide phosphatase SAC1 accumulates at the Golgi in quiescent cells and down-regulates anterograde trafficking by depleting Golgi PI(4)P. Golgi localization requires oligomerization of SAC1 and recruitment of the coat protein (COP) II complex. When quiescent cells are stimulated by mitogens, SAC1 rapidly shuttles back to the endoplasmic reticulum (ER), thus releasing the brake on Golgi secretion. The p38 mitogen-activated kinase (MAPK) pathway induces dissociation of SAC1 oligomers after mitogen stimulation, which triggers COP-I–mediated retrieval of SAC1 to the ER. Inhibition of p38 MAPK abolishes growth factor–induced Golgi-to-ER shuttling of SAC1 and slows secretion. These results suggest direct roles for p38 MAPK and SAC1 in transmitting growth signals to the secretory machinery. PMID:18299350

Overcoming resistance to single-agent therapy for oncogenic BRAF gene fusions via combinatorial targeting of MAPK and PI3K/mTOR signaling pathways

PubMed Central

Jain, Payal; Silva, Amanda; Han, Harry J.; Lang, Shih-Shan; Zhu, Yuankun; Boucher, Katie; Smith, Tiffany E.; Vakil, Aesha; Diviney, Patrick; Choudhari, Namrata; Raman, Pichai; Busch, Christine M.; Delaney, Tim; Yang, Xiaodong; Olow, Aleksandra K.; Mueller, Sabine; Haas-Kogan, Daphne; Fox, Elizabeth; Storm, Phillip B.; Resnick, Adam C.; Waanders, Angela J.

2017-01-01

Pediatric low-grade gliomas (PLGGs) are frequently associated with activating BRAF gene fusions, such as KIAA1549-BRAF, that aberrantly drive the mitogen activated protein kinase (MAPK) pathway. Although RAF inhibitors (RAFi) have been proven effective in BRAF-V600E mutant tumors, we have previously shown how the KIAA1549-BRAF fusion can be paradoxically activated by RAFi. While newer classes of RAFi, such as PLX8394, have now been shown to inhibit MAPK activation by KIAA1549-BRAF, we sought to identify alternative MAPK pathway targeting strategies using clinically relevant MEK inhibitors (MEKi), along with potential escape mechanisms of acquired resistance to single-agent MAPK pathway therapies. We demonstrate effectiveness of multiple MEKi against diverse BRAF-fusions with novel N-terminal partners, with trametinib being the most potent. However, resistance to MEKi or PLX8394 develops via increased RTK expression causing activation of PI3K/mTOR pathway in BRAF-fusion expressing resistant clones. To circumvent acquired resistance, we show potency of combinatorial targeting with trametinib and everolimus, an mTOR inhibitor (mTORi) against multiple BRAF-fusions. While single-agent mTORi and MEKi PLGG clinical trials are underway, our study provides preclinical rationales for using MEKi and mTORi combinatorial therapy to stave off or prevent emergent drug-resistance in BRAF-fusion driven PLGGs. PMID:29156677

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

Arachidonic acid stimulates DNA synthesis in brown preadipocytes through the activation of protein kinase C and MAPK.

PubMed

Garcia, Bibian; Martinez-de-Mena, Raquel; Obregon, Maria-Jesus

2012-10-01

Arachidonic acid (AA) is a polyunsaturated fatty acid that stimulates the proliferation of many cellular types. We studied the mitogenic potential of AA in rat brown preadipocytes in culture and the signaling pathways involved. AA is a potent mitogen which induces 4-fold DNA synthesis in brown preadipocytes. The AA mitogenic effect increases by NE addition. AA also increases the mitogenic action of different growth factor combinations. Other unsaturated and saturated fatty acids do not stimulate DNA synthesis to the same extent as AA. We analyzed the role of PKC and MEK/MAPK signaling pathways. PKC inhibition by bisindolilmaleimide I (BIS) abolishes AA and phorbol ester stimulation of DNA synthesis and reduces the mitogenic activity of different growth factors in brown preadipocytes. Brown preadipocytes in culture express PKC α, δ, ε and ζ isoforms. Pretreatment with high doses of the phorbol ester PDBu, induces downregulation of PKCs ε and δ and reproduces the effect of BIS indicating that AA-dependent induction of DNA synthesis requires PKC activity. AA also activates MEK/MAPK pathway and the inhibition of MEK activity inhibits AA stimulation of DNA synthesis and brown adipocyte proliferation. Inhibition of PKC δ by rottlerin abolishes AA-dependent stimulation of DNA synthesis and MAPK activation, whereas PKC ε inhibition does not produce any effect. In conclusion, our results identify AA as a potent mitogen for brown adipocytes and demonstrate the involvement of the PDBu-sensitive PKC δ isoform and MEK/MAPK pathway in AA-induced proliferation of brown adipocytes. Increased proliferative activity might increase the thermogenic capacity of brown fat. Copyright © 2012 Elsevier B.V. All rights reserved.

Uridine 5′-Triphosphate Promotes In Vitro Schwannoma Cell Migration through Matrix Metalloproteinase-2 Activation

PubMed Central

Martiañez, Tania; Segura, Mònica; Figueiro-Silva, Joana; Grijota-Martinez, Carmen; Trullas, Ramón; Casals, Núria

2014-01-01

In response to peripheral nerve injury, Schwann cells adopt a migratory phenotype and modify the extracellular matrix to make it permissive for cell migration and axonal re-growth. Uridine 5′-triphosphate (UTP) and other nucleotides are released during nerve injury and activate purinergic receptors expressed on the Schwann cell surface, but little is known about the involvement of purine signalling in wound healing. We studied the effect of UTP on Schwannoma cell migration and wound closure and the intracellular signaling pathways involved. We found that UTP treatment induced Schwannoma cell migration through activation of P2Y2 receptors and through the increase of extracellular matrix metalloproteinase-2 (MMP-2) activation and expression. Knockdown P2Y2 receptor or MMP-2 expression greatly reduced wound closure and MMP-2 activation induced by UTP. MMP-2 activation evoked by injury or UTP was also mediated by phosphorylation of all 3 major mitogen-activated protein kinases (MAPKs): JNK, ERK1/2, and p38. Inhibition of these MAPK pathways decreased both MMP-2 activation and cell migration. Interestingly, MAPK phosphorylation evoked by UTP exhibited a biphasic pattern, with an early transient phosphorylation 5 min after treatment, and a late and sustained phosphorylation that appeared at 6 h and lasted up to 24 h. Inhibition of MMP-2 activity selectively blocked the late, but not the transient, phase of MAPK activation. These results suggest that MMP-2 activation and late MAPK phosphorylation are part of a positive feedback mechanism to maintain the migratory phenotype for wound healing. In conclusion, our findings show that treatment with UTP stimulates in vitro Schwannoma cell migration and wound repair through a MMP-2-dependent mechanism via P2Y2 receptors and MAPK pathway activation. PMID:24905332

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.

Involvement of Mos-MEK-MAPK pathway in cytostatic factor (CSF) arrest in eggs of the parthenogenetic insect, Athalia rosae.

PubMed

Yamamoto, Daisuke S; Tachibana, Kazunori; Sumitani, Megumi; Lee, Jae Min; Hatakeyama, Masatsugu

2008-01-01

Extensive survey of meiotic metaphase II arrest during oocyte maturation in vertebrates revealed that the mitogen-activated protein kinase (MAPK) pathway regulated by the c-mos proto-oncogene product, Mos, has an essential role in cytostatic activity, termed cytostatic factor (CSF). In contrast, little is known in invertebrates in which meiotic arrest occurs in most cases at metaphase I (MI arrest). A parthenogenetic insect, the sawfly Athalia rosae, in which artificial egg activation is practicable, has advantages to investigate the mechanisms of MI arrest. Both the MAPK/extracellular signal-regulated protein kinase kinase (MEK) and MAPK were phosphorylated and maintained active in MI-arrested sawfly eggs, whereas they were dephosphorylated soon after egg activation. Treatment of MI-arrested eggs with U0126, an inhibitor of MEK, resulted in dephosphorylation of MAPK and MI arrest was resumed. The sawfly c-mos gene orthologue encoding a serine/threonine kinase was cloned and analyzed. It was expressed in nurse cells in the ovaries. To examine CSF activity of the sawfly Mos, synthesized glutathione S-transferase (GST)-fusion sawfly Mos protein was injected into MI-resumed eggs in which MEK and MAPK were dephosphorylated. Both MEK and MAPK were phosphorylated again upon injection. In these GST-fusion sawfly Mos-injected eggs subsequent mitotic (syncytial) divisions were blocked and embryonic development was ceased. These results demonstrated that the MEK-MAPK pathway was involved in maintaining CSF arrest in sawfly eggs and Mos functioned as its upstream regulatory molecule.

Transforming growth factor β-activated kinase 1 transcriptionally suppresses hepatitis B virus replication.

PubMed

Pang, Jinke; Zhang, Geng; Lin, Yong; Xie, Zhanglian; Liu, Hongyan; Tang, Libo; Lu, Mengji; Yan, Ran; Guo, Haitao; Sun, Jian; Hou, Jinlin; Zhang, Xiaoyong

2017-01-03

Hepatitis B Virus (HBV) replication in hepatocytes is restricted by the host innate immune system and related intracellular signaling pathways. Transforming growth factor β-activated kinase 1 (TAK1) is a key mediator of toll-like receptors and pro-inflammatory cytokine signaling pathways. Here, we report that silencing or inhibition of endogenous TAK1 in hepatoma cell lines leads to an upregulation of HBV replication, transcription, and antigen expression. In contrast, overexpression of TAK1 significantly suppresses HBV replication, while an enzymatically inactive form of TAK1 exerts no effect. By screening TAK1-associated signaling pathways with inhibitors and siRNAs, we found that the MAPK-JNK pathway was involved in TAK1-mediated HBV suppression. Moreover, TAK1 knockdown or JNK pathway inhibition induced the expression of farnesoid X receptor α, a transcription factor that upregulates HBV transcription. Finally, ectopic expression of TAK1 in a HBV hydrodynamic injection mouse model resulted in lower levels of HBV DNA and antigens in both liver and serum. In conclusion, our data suggest that TAK1 inhibits HBV primarily at viral transcription level through activation of MAPK-JNK pathway, thus TAK1 represents an intrinsic host restriction factor for HBV replication in hepatocytes.

Substance P activates both contractile and inflammatory pathways in lymphatics through the neurokinin receptors NK1R and NK3R.

PubMed

Chakraborty, Sanjukta; Nepiyushchikh, Zhanna; Davis, Michael J; Zawieja, David C; Muthuchamy, Mariappan

2011-01-01

The aim of this study was to elucidate the molecular signaling mechanisms by which substance P (SP) modulates lymphatic muscle contraction and to determine whether SP stimulates both contractile as well as inflammatory pathways in the lymphatics. A rat mesenteric lymphatic muscle cell culture model (RMLMCs) and known specific pharmacological inhibitors were utilized to delineate SP-mediated signaling pathways in lymphatics. We detected expression of neurokinin receptor 1 (NK1R) and neurokinin receptor 3 (NK3R) in RMLMCs. SP stimulation increased phosphorylation of myosin light chain 20 (MLC₂₀) as well as p38 mitogen associated protein kinase (p38-MAPK) and extracellular signal regulated kinase (ERK1/2) indicating activation of both a contractile and a pro-inflammatory MAPK pathway. Pharmacological inhibition of both NK1R and NK3R significantly affected the downstream SP signaling. We further examined whether there was any crosstalk between the two pathways upon SP stimulation. Inhibition of ERK1/2 decreased levels of p-MLC₂₀ after SP activation, in a PKC dependent manner, indicating a potential crosstalk between these two pathways. These data provide the first evidence that SP-mediated crosstalk between pro-inflammatory and contractile signaling mechanisms exists in the lymphatic system and may be an important bridge between lymphatic function modulation and inflammation. © 2010 John Wiley & Sons Ltd.

Substance P activates both contractile and inflammatory pathways in lymphatics through the neurokinin receptors NK1R and NK3R

PubMed Central

Chakraborty, Sanjukta; Nepiyushchikh, Zhanna; Davis, Michael J.; Zawieja, David C.; Muthuchamy, Mariappan

2010-01-01

Objective The aim of this study was to elucidate the molecular signaling mechanisms by which substance P (SP) modulates lymphatic muscle contraction and to determine whether SP stimulates both contractile as well as inflammatory pathways in the lymphatics. Methods A rat mesenteric lymphatic muscle cell culture model (RMLMCs) and known specific pharmacological inhibitors were utilized to delineate SP mediated signaling pathways in lymphatics. Results We detected expression of neurokinin receptor 1 (NK1R) and neurokinin receptor 3 (NK3R) in RMLMCs. SP stimulation increased phosphorylation of myosin light chain 20 (MLC20) as well as p38 mitogen associated protein kinase (p38-MAPK) and extracellular signal regulated kinase (ERK1/2) indicating activation of both a contractile and a pro-inflammatory MAPK pathway. Pharmacological inhibition of both NK1R and NK3R significantly affected the downstream SP signaling. We further examined whether there was any crosstalk between the two pathways upon SP stimulation. Inhibition of ERK1/2 decreased levels of p-MLC20 after SP activation, in a PKC dependent manner, indicating a potential crosstalk between these two pathways. Conclusions These data provide the first evidence that SP mediated crosstalk between pro-inflammatory and contractile signaling mechanisms exists in the lymphatic system and may be an important bridge between lymphatic function modulation and inflammation. PMID:21166923

The Kynurenine 3-Monooxygenase Encoding Gene, BcKMO, Is Involved in the Growth, Development, and Pathogenicity of Botrytis cinerea

PubMed Central

Zhang, Kang; Yuan, Xuemei; Zang, Jinping; Wang, Min; Zhao, Fuxin; Li, Peifen; Cao, Hongzhe; Han, Jianmin; Xing, Jihong; Dong, Jingao

2018-01-01

A pathogenic mutant, BCG183, was obtained by screening the T-DNA insertion library of Botrytis cinerea. A novel pathogenicity-related gene BcKMO, which encodes kynurenine 3-monooxygenase (KMO), was isolated and identified via thermal asymmetric interlaced PCR, bioinformatics analyses, and KMO activity measurement. The mutant BCG183 grew slowly, did not produce conidia and sclerotia, had slender hyphae, and presented enhanced pathogenicity. The phenotype and pathogenicity of the BcKMO-complementing mutant (BCG183/BcKMO) were similar to those of the wild-type (WT) strain. The activities of polymethylgalacturonase, polygalacturonase, and toxins were significantly higher, whereas acid production was significantly decreased in the mutant BCG183, when compared with those in the WT and BCG183/BcKMO. Moreover, the sensitivity of mutant BCG183 to NaCl and KCl was remarkably increased, whereas that to fluconazole, Congo Red, menadione, H2O2, and SQ22536 and U0126 [cAMP-dependent protein kinase (cAMP) and mitogen-activated protein kinase (MAPK) signaling pathways inhibitors, respectively] were significantly decreased compared with the other strains. Furthermore, the key genes involved in the cAMP and MAPK signaling pathways, Pka1, Pka2, PkaR, Bcg2, Bcg3, bmp1, and bmp3, were significantly upregulated or downregulated in the mutant BCG183. BcKMO expression levels were also upregulated or downregulated in the RNAi mutants of the key genes involved in the cAMP and MAPK signaling pathways. These findings indicated that BcKMO positively regulates growth and development, but negatively regulates pathogenicity of B. cinerea. Furthermore, BcKMO was found to be involved in controlling cell wall degrading enzymes activity, toxins activity, acid production, and cell wall integrity, and participate in cAMP and MAPK signaling pathways of B. cinerea. PMID:29867912

The Protective Effect of Rhizoma Dioscoreae Extract against Alveolar Bone Loss in Ovariectomized Rats via Regulating Wnt and p38 MAPK Signaling

PubMed Central

Zhang, Zhiguo; Xiang, Lihua; Bai, Dong; Wang, Wenlai; Li, Yan; Pan, Jinghua; Liu, Hong; Wang, Shaojun; Xiao, Gary Guishan; Ju, Dahong

2014-01-01

Aim: The aim of this study was to evaluate the osteoprotective effect of aqueous Rhizoma Dioscoreae extract (RDE) on the alveolar bone of rats with ovariectomy-induced bone loss. Methods: Female Wistar rats were subjected to either ovariectomy or a sham operation (SHAM). The ovariectomized (OVX) rats were treated with vehicle (OVX) or RDE by oral gavage or with 17β-estradiol (E2) subcutaneously. After treatments, the bone mineral density (BMD), the three-dimensional bone architecture of the alveolar bone and the plasma biomarkers of bone turnover were analyzed to assess bone metabolism, and the histomorphometry of the alveolar bone was observed. Microarrays were used to evaluate gene expression profiles in alveolar bone from RDE-treated and OVX rats. The differential expression of genes was further analyzed using Ingenuity Pathway Analysis (IPA). The key findings were verified using real-time quantitative RT-PCR (qRT-PCR). Results: Our results showed that RDE inhibited alveolar bone loss in OVX rats. Compared to the OVX rats, the RDE-treated rats showed upregulated expression levels of 207 genes and downregulated expression levels of 176 genes in the alveolar bone. The IPA showed that several genes had the potential to code for proteins that were involved in the Wnt/β-catenin signaling pathway (Wnt7a, Fzd2, Tcf3, Spp1, Frzb, Sfrp2 and Sfrp4) and the p38 MAPK signaling pathway (Il1rn and Mapk14). Conclusion: These experiments revealed that RDE could inhibit ovariectomy-induced alveolar bone loss in rats. The mechanism of this anti-osteopenic effect in alveolar bone may be involved in the reduced abnormal bone remodeling, which is associated with the modulation of the Wnt/β-catenin and the p38 MAPK signaling pathways via gene regulation. PMID:25514564

The Kynurenine 3-Monooxygenase Encoding Gene, BcKMO, Is Involved in the Growth, Development, and Pathogenicity of Botrytis cinerea.

PubMed

Zhang, Kang; Yuan, Xuemei; Zang, Jinping; Wang, Min; Zhao, Fuxin; Li, Peifen; Cao, Hongzhe; Han, Jianmin; Xing, Jihong; Dong, Jingao

2018-01-01

A pathogenic mutant, BCG183, was obtained by screening the T-DNA insertion library of Botrytis cinerea . A novel pathogenicity-related gene BcKMO , which encodes kynurenine 3-monooxygenase (KMO), was isolated and identified via thermal asymmetric interlaced PCR, bioinformatics analyses, and KMO activity measurement. The mutant BCG183 grew slowly, did not produce conidia and sclerotia, had slender hyphae, and presented enhanced pathogenicity. The phenotype and pathogenicity of the BcKMO -complementing mutant (BCG183/ BcKMO ) were similar to those of the wild-type (WT) strain. The activities of polymethylgalacturonase, polygalacturonase, and toxins were significantly higher, whereas acid production was significantly decreased in the mutant BCG183, when compared with those in the WT and BCG183/ BcKMO . Moreover, the sensitivity of mutant BCG183 to NaCl and KCl was remarkably increased, whereas that to fluconazole, Congo Red, menadione, H 2 O 2 , and SQ22536 and U0126 [cAMP-dependent protein kinase (cAMP) and mitogen-activated protein kinase (MAPK) signaling pathways inhibitors, respectively] were significantly decreased compared with the other strains. Furthermore, the key genes involved in the cAMP and MAPK signaling pathways, Pka1 , Pka2 , PkaR , Bcg2 , Bcg3 , bmp1 , and bmp3, were significantly upregulated or downregulated in the mutant BCG183. BcKMO expression levels were also upregulated or downregulated in the RNAi mutants of the key genes involved in the cAMP and MAPK signaling pathways. These findings indicated that BcKMO positively regulates growth and development, but negatively regulates pathogenicity of B. cinerea . Furthermore, BcKMO was found to be involved in controlling cell wall degrading enzymes activity, toxins activity, acid production, and cell wall integrity, and participate in cAMP and MAPK signaling pathways of B. cinerea .

Halofuginone inhibits Smad3 phosphorylation via the PI3K/Akt and MAPK/ERK pathways in muscle cells: Effect on myotube fusion

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

Roffe, Suzy; Hagai, Yosey; Institute of Animal Sciences, Volcani Center, Bet Dagan 50250

2010-04-01

Halofuginone, a novel inhibitor of Smad3 phosphorylation, has been shown to inhibit muscle fibrosis and to improve cardiac and skeletal muscle functions in the mdx mouse model of Duchenne muscular dystrophy. Here, we demonstrate that halofuginone promotes the phosphorylation of Akt and mitogen-activated protein kinase (MAPK) family members in a C2 muscle cell line and in primary myoblasts derived from wild-type and mdx mice diaphragms. Halofuginone enhanced the association of phosphorylated Akt and MAPK/extracellular signal-regulated protein kinase (ERK) with the non-phosphorylated form of Smad3, accompanied by a reduction in Smad3 phosphorylation levels. This reduction was reversed by inhibitors of themore » phosphoinositide 3'-kinase/Akt (PI3K/Akt) and MAPK/ERK pathways, suggesting their specific role in mediating halofuginone's inhibitory effect on Smad3 phosphorylation. Halofuginone enhanced Akt, MAPK/ERK and p38 MAPK phosphorylation and inhibited Smad3 phosphorylation in myotubes, all of which are crucial for myotube fusion. In addition, halofuginone increased the association Akt and MAPK/ERK with Smad3. As a consequence, halofuginone promoted myotube fusion, as reflected by an increased percentage of C2 and mdx myotubes containing high numbers of nuclei, and this was reversed by specific inhibitors of the PI3K and MAPK/ERK pathways. Together, the data suggest a role, either direct or via inhibition of Smad3 phosphorylation, for Akt or MAPK/ERK in halofuginone-enhanced myotube fusion, a feature which is crucial to improving muscle function in muscular dystrophies.« less

Tanshinone IIA inhibits AGEs-induced proliferation and migration of cultured vascular smooth muscle cells by suppressing ERK1/2 MAPK signaling

PubMed Central

Lu, Ming; Luo, Ying; Hu, Pengfei; Dou, Liping; Huang, Shuwei

2018-01-01

Objective(s): Vascular smooth muscle cells (VSMCs) play a key role in the pathogenesis of diabetic vascular disease. Our current study sought to explore the effects of tanshinone IIA on the proliferation and migration of VSMCs induced by advanced glycation end products (AGEs). Materials and Methods: In this study, we examined the effects of tanshinone IIA by cell proliferation assay and cell migration assay. And we explored the underlying mechanism by Western blotting. Results: AGEs significantly induced the proliferation and migration of VSMCs, but treatment with tanshinone IIA attenuated these effects. AGEs could increase the activity of the ERK1/2 and p38 pathways but not the JNK pathway. Treatment with tanshinone IIA inhibited the AGEs-induced activation of the ERK1/2 pathway but not the p38 pathway. Conclusion: Tanshinone IIA inhibits AGEs-induced proliferation and migration of VSMCs by suppressing the ERK1/2 MAPK signaling pathway. PMID:29372041

Apical accumulation of the Sevenless receptor tyrosine kinase during Drosophila eye development is promoted by the small GTPase Rap1.

PubMed

Baril, Caroline; Lefrançois, Martin; Sahmi, Malha; Knævelsrud, Helene; Therrien, Marc

2014-08-01

The Ras/MAPK-signaling pathway plays pivotal roles during development of metazoans by controlling cell proliferation and cell differentiation elicited, in several instances, by receptor tyrosine kinases (RTKs). While the internal mechanism of RTK-driven Ras/MAPK signaling is well understood, far less is known regarding its interplay with other co-required signaling events involved in developmental decisions. In a genetic screen designed to identify new regulators of RTK/Ras/MAPK signaling during Drosophila eye development, we identified the small GTPase Rap1, PDZ-GEF, and Canoe as components contributing to Ras/MAPK-mediated R7 cell differentiation. Rap1 signaling has recently been found to participate in assembling cadherin-based adherens junctions in various fly epithelial tissues. Here, we show that Rap1 activity is required for the integrity of the apical domains of developing photoreceptor cells and that reduced Rap1 signaling hampers the apical accumulation of the Sevenless RTK in presumptive R7 cells. It thus appears that, in addition to its role in cell-cell adhesion, Rap1 signaling controls the partitioning of the epithelial cell membrane, which in turn influences signaling events that rely on apico-basal cell polarity. Copyright © 2014 by the Genetics Society of America.

Pirfenidone Induces G1 Arrest in Human Tenon's Fibroblasts In Vitro Involving AKT and MAPK Signaling Pathways.

PubMed

Guo, Xiujuan; Yang, Yangfan; Liu, Liling; Liu, Xiaoan; Xu, Jiangang; Wu, Kaili; Yu, Minbin

2017-06-01

To investigate the underlying mechanism by which pirfenidone blocks the transition from the G1 to S phase in primary human Tenon's fibroblasts. Primary human Tenon's fibroblasts were characterized by immunocytofluorescence staining with vimentin, fibroblast surface protein, and cytokeratin. After treating Tenon's fibroblasts with pirfenidone under proliferation conditions (10% fetal bovine serum), cell proliferation was measured using a WST-1 assay. Progression through the cell cycle was analyzed by flow cytometry. The expression of CDK2, CDK6, cyclinD1, cyclinD3, and cyclinE and the phosphorylation of AKT, ERK1/2/MAPK, JNK/MAPK, and p38 MAPK were estimated using western blot analysis. Under proliferative conditions, pirfenidone inhibited Tenon's fibroblasts proliferation and arrested the cell cycle at the G1 phase; decreased the phosphorylation of AKT, GSK3β, ERK1/2/MAPK, and JNK/MAPK; increased the phosphorylation of p38 MAPK; and inhibited CDK2, CDK6, cyclin D1, cyclin D3, and cyclin E in a dose-dependent manner. Inhibitors of AKT (LY294002), ERK1/2 (U0126), and JNK (SP600125) arrested the G1/S transition, similar to the effect of pirfenidone. The p38 inhibitor (SB202190) decreased the G1-blocking effect of pirfenidone. The expression of CDK2, CDK6, cyclin D1, and cyclin D3 were inhibited by LY294002, U0126, and SP600125. SB202190 attenuated the pirfenidone-induced reduction of CDK2, CDK6, cyclin D1, cyclin D3, and cyclin E. Pirfenidone inhibited HTFs proliferation and induced G1 arrest by downregulating CDKs and cyclins involving the AKT/GSK3β and MAPK signaling pathways.

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

PubMed

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

2017-11-21

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

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

PubMed

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

2014-10-01

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

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

PubMed Central

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

2017-01-01

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

Integrated analysis of breast cancer cell lines reveals unique signaling pathways

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

Heiser, Laura M.; Wang, Nicholas J.; Talcott, Carolyn L.

Cancer is a heterogeneous disease resulting from the accumulation of genetic defects that negatively impact control of cell division, motility, adhesion and apoptosis. Deregulation in signaling along the EGFR-MAPK pathway is common in breast cancer, though the manner in which deregulation occurs varies between both individuals and cancer subtypes. We were interested in identifying subnetworks within the EGFR-MAPK pathway that are similarly deregulated across subsets of breast cancers. To that end, we mapped genomic, transcriptional and proteomic profiles for 30 breast cancer cell lines onto a curated Pathway Logic symbolic systems model of EGFR-MEK signaling. This model was comprised ofmore » 539 molecular states and 396 rules governing signaling between active states. We analyzed these models and identified several subtype specific subnetworks, including one that suggested PAK1 is particularly important in regulating the MAPK cascade when it is over-expressed. We hypothesized that PAK1 overexpressing cell lines would have increased sensitivity to MEK inhibitors. We tested this experimentally by measuring quantitative responses of 20 breast cancer cell lines to three MEK inhibitors. We found that PAK1 over-expressing luminal breast cancer cell lines are significantly more sensitive to MEK inhibition as compared to those that express PAK1 at low levels. This indicates that PAK1 over-expression may be a useful clinical marker to identify patient populations that may be sensitive to MEK inhibitors. All together, our results support the utility of symbolic system biology models for identification of therapeutic approaches that will be effective against breast cancer subsets.« less

Fisetin administration improves LPS-induced acute otitis media in mouse in vivo.

PubMed

Li, Peng; Chen, Dan; Huang, Yang

2018-07-01

Acute otitis media is one of the most common infectious diseases worldwide in spite of the widespread vaccination. The present study was conducted to explore the effects of fisetin on mouse acute otitis media models. The animal models were established by lipopolysaccharide (LPS) injection into the middle ear of mice via the tympanic membrane. Fisetin was administered to mice for ten days through intragastric administration immediate after LPS application. Hematoxylin and eosin (H&E) staining was performed and the pro-inflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), IL-6 and VEGF, were measured through enzyme-linked immunosorbent assay (ELISA) method and RT-qPCR analysis. Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathway was detected by immunoblotting assays. Reactive oxygen species (ROS) generated levels were determined through assessment of anti-oxidants, and TXNIP/MAPKs signaling pathways were explored to reveal the possible molecular mechanism for acute otitis media progression and the function of fisetin. Fisetin reduced mucosal thickness caused by LPS. In fisetin-treated animals, pro-inflammatory cytokine release was downregulated accompanied with TLR4/NF-κB inactivation. ROS production was significantly decreased in comparison to the LPS-treated group. The TXNIP/MAPKs signaling pathway was inactivated for fisetin treatment in LPS-induced mice with acute otitis media. The above results indicated that fisetin improved acute otitis media through inflammation and ROS suppression via inactivating TLR4/NF-κB and TXNIP/MAPKs signaling pathways.

Fisetin administration improves LPS-induced acute otitis media in mouse in vivo

PubMed Central

Li, Peng; Chen, Dan; Huang, Yang

2018-01-01

Acute otitis media is one of the most common infectious diseases worldwide in spite of the widespread vaccination. The present study was conducted to explore the effects of fisetin on mouse acute otitis media models. The animal models were established by lipopolysaccharide (LPS) injection into the middle ear of mice via the tympanic membrane. Fisetin was administered to mice for ten days through intragastric administration immediate after LPS application. Hematoxylin and eosin (H&E) staining was performed and the pro-inflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), IL-6 and VEGF, were measured through enzyme-linked immunosorbent assay (ELISA) method and RT-qPCR analysis. Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathway was detected by immunoblotting assays. Reactive oxygen species (ROS) generated levels were determined through assessment of anti-oxidants, and TXNIP/MAPKs signaling pathways were explored to reveal the possible molecular mechanism for acute otitis media progression and the function of fisetin. Fisetin reduced mucosal thickness caused by LPS. In fisetin-treated animals, pro-inflammatory cytokine release was downregulated accompanied with TLR4/NF-κB inactivation. ROS production was significantly decreased in comparison to the LPS-treated group. The TXNIP/MAPKs signaling pathway was inactivated for fisetin treatment in LPS-induced mice with acute otitis media. The above results indicated that fisetin improved acute otitis media through inflammation and ROS suppression via inactivating TLR4/NF-κB and TXNIP/MAPKs signaling pathways. PMID:29568876

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

PubMed

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

2016-07-01

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

Dystroglycan modulates the ability of insulin-like growth factor-1 to promote oligodendrocyte differentiation.

PubMed

Galvin, Jason; Eyermann, Christopher; Colognato, Holly

2010-11-15

The adhesion receptor dystroglycan positively regulates terminal differentiation of oligodendrocytes, but the mechanism by which this occurs remains unclear. Using primary oligodendrocyte cultures, we identified and examined a connection between dystroglycan and the ability of insulin-like growth factor-1 (IGF-1) to promote oligodendrocyte differentiation. Consistent with previous reports, treatment with exogenous IGF-1 caused an increase in MBP protein that was preceded by activation of PI3K (AKT) and MAPK (ERK) signaling pathways. The extracellular matrix protein laminin was further shown to potentiate the effect of IGF-1 on oligodendrocyte differentiation. Depletion of the laminin receptor dystroglycan using siRNA, however, blocked the ability of IGF-1 to promote oligodendrocyte differentiation of cells grown on laminin, suggesting a role for dystroglycan in IGF-1-mediated differentiation. Indeed, loss of dystroglycan led to a reduction in the ability of IGF-1 to activate MAPK, but not PI3K, signaling pathways. Pharmacological inhibition of MAPK signaling also prevented IGF-1-induced increases in myelin basic protein (MBP), indicating that MAPK signaling was necessary to drive IGF-1-mediated enhancement of oligodendrocyte differentiation. Using immunoprecipitation, we found that dystroglycan, the adaptor protein Grb2, and insulin receptor substrate-1 (IRS-1), were associated in a protein complex. Taken together, our results suggest that the positive regulatory effect of laminin on oligodendrocyte differentiation may be attributed, at least in part, to dystroglycan's ability to promote IGF-1-induced differentiation.

Non-thermal plasma inhibits human cervical cancer HeLa cells invasiveness by suppressing the MAPK pathway and decreasing matrix metalloproteinase-9 expression

NASA Astrophysics Data System (ADS)

Li, Wei; Yu, K. N.; Bao, Lingzhi; Shen, Jie; Cheng, Cheng; Han, Wei

2016-01-01

Non-thermal plasma (NTP) has been proposed as a novel therapeutic method for anticancer treatment. However, the mechanism underlying its biological effects remains unclear. In this study, we investigated the inhibitory effect of NTP on the invasion of HeLa cells, and explored the possible mechanism. Our results showed that NTP exposure for 20 or 40 s significantly suppressed the migration and invasion of HeLa cells on the basis of matrigel invasion assay and wound healing assay, respectively. Moreover, NTP reduced the activity and protein expression of the matrix metalloproteinase (MMP)-9 enzyme. Western blot analysis indicated that NTP exposure effectively decreased phosphorylation level of both ERK1/2 and JNK, but not p38 MAPK. Furthermore, treatment with MAPK signal pathway inhibitors or NTP all exhibited significant depression of HeLa cells migration and MMP-9 expression. The result showed that NTP synergistically suppressed migration and MMP-9 expression in the presence of ERK1/2 inhibitor and JNK inhibitor, but not p38 MAPK inhibitor. Taken together, these findings suggested that NTP exposure inhibited the migration and invasion of HeLa cells via down-regulating MMP-9 expression in ERK1/2 and JNK signaling pathways dependent manner. These findings provide hints to the potential clinical research and therapy of NTP on cervical cancer metastasis.

Effect of Gelam Honey on the Oxidative Stress-Induced Signaling Pathways in Pancreatic Hamster Cells

PubMed Central

Zaman Safi, Sher; Mohd Yusof, Kamaruddin; Shah Ismail, Ikram; Devi Sekaran, Shamala; Qvist, Rajes

2013-01-01

Background. Oxidative stress induced by reactive oxygen and nitrogen species is critically involved in the impairment of β-cell function during the development of diabetes. Methods. HIT-T15 cells were cultured in 5% CO2 and then preincubated with Gelam honey extracts (20, 40, 60, and 80 µg/mL) as well as quercetin (20, 40, 60, and 80 µM), prior to stimulation by 20 and 50 mM of glucose. Cell lysate was collected to determine the effect of honey extracts and quercetin on the stress activated NF-κB, MAPK pathways, and the Akt (ser473) activated insulin signaling pathway. Results. HIT-T15 cells cultured under hyperglycemic conditions demonstrated insulin resistance with a significant increase in the levels of MAPK, NF-κB, and IRS-1 serine phosphorylation (ser307); however, Akt expression and insulin contents are significantly decreased. Pretreatment with quercetin and Gelam honey extract improved insulin resistance and insulin content by reducing the expression of MAPK, NF-κB, and IRS-1 serine phosphorylation (ser307) and increasing the expression of Akt significantly. Conclusion. Gelam honey-induced differential expression of MAPK, NF-κB, IRS-1 (ser307), and Akt in HIT-T15 cells shows that Gelam honey exerts protective effects against diabetes- and hyperglycemia-induced oxidative stress by improving insulin content and insulin resistance. PMID:24324490

Costunolide ameliorates lipoteichoic acid-induced acute lung injury via attenuating MAPK signaling pathway.

PubMed

Chen, Zhengxu; Zhang, Dan; Li, Man; Wang, Baolong

2018-06-12

Lipoteichoic acid (LTA)-induced acute lung injury (ALI) is an experimental model for mimicking Gram-positive bacteria-induced pneumonia that is a refractory disease with lack of effective medicines. Here, we reported that costunolide, a sesquiterpene lactone, ameliorated LTA-induced ALI. Costunolide treatment reduced LTA-induced neutrophil lung infiltration, cytokine and chemokine production (TNF-α, IL-6 and KC), and pulmonary edema. In response to LTA challenge, treatment with costunolide resulted less iNOS expression and produced less inflammatory cytokines in bone marrow derived macrophages (BMDMs). Pretreatment with costunolide also attenuated the LTA-induced the phosphorylation of p38 MAPK and ERK in BMDMs. Furthermore, costunolide treatment reduced the phosphorylation of TAK1 and inhibited the interaction of TAK1 with Tab1. In conclusion, we have demonstrated that costunolide protects against LTA-induced ALI via inhibiting TAK1-mediated MAPK signaling pathway, and our studies suggest that costunolide is a promising agent for treatment of Gram-positive bacteria-mediated pneumonia. Copyright © 2018 Elsevier B.V. All rights reserved.

Activation of the Saccharomyces cerevisiae filamentation/invasion pathway by osmotic stress in high-osmolarity glycogen pathway mutants

NASA Technical Reports Server (NTRS)

Davenport, K. D.; Williams, K. E.; Ullmann, B. D.; Gustin, M. C.; McIntire, L. V. (Principal Investigator)

1999-01-01

Mitogen-activated protein kinase (MAPK) cascades are frequently used signal transduction mechanisms in eukaryotes. Of the five MAPK cascades in Saccharomyces cerevisiae, the high-osmolarity glycerol response (HOG) pathway functions to sense and respond to hypertonic stress. We utilized a partial loss-of-function mutant in the HOG pathway, pbs2-3, in a high-copy suppressor screen to identify proteins that modulate growth on high-osmolarity media. Three high-copy suppressors of pbs2-3 osmosensitivity were identified: MSG5, CAK1, and TRX1. Msg5p is a dual-specificity phosphatase that was previously demonstrated to dephosphorylate MAPKs in yeast. Deletions of the putative MAPK targets of Msg5p revealed that kss1delta could suppress the osmosensitivity of pbs2-3. Kss1p is phosphorylated in response to hyperosmotic shock in a pbs2-3 strain, but not in a wild-type strain nor in a pbs2-3 strain overexpressing MSG5. Both TEC1 and FRE::lacZ expressions are activated in strains lacking a functional HOG pathway during osmotic stress in a filamentation/invasion-pathway-dependent manner. Additionally, the cellular projections formed by a pbs2-3 mutant on high osmolarity are absent in strains lacking KSS1 or STE7. These data suggest that the loss of filamentation/invasion pathway repression contributes to the HOG mutant phenotype.

Activation of the Saccharomyces cerevisiae filamentation/invasion pathway by osmotic stress in high-osmolarity glycogen pathway mutants.

PubMed Central

Davenport, K D; Williams, K E; Ullmann, B D; Gustin, M C

1999-01-01

Mitogen-activated protein kinase (MAPK) cascades are frequently used signal transduction mechanisms in eukaryotes. Of the five MAPK cascades in Saccharomyces cerevisiae, the high-osmolarity glycerol response (HOG) pathway functions to sense and respond to hypertonic stress. We utilized a partial loss-of-function mutant in the HOG pathway, pbs2-3, in a high-copy suppressor screen to identify proteins that modulate growth on high-osmolarity media. Three high-copy suppressors of pbs2-3 osmosensitivity were identified: MSG5, CAK1, and TRX1. Msg5p is a dual-specificity phosphatase that was previously demonstrated to dephosphorylate MAPKs in yeast. Deletions of the putative MAPK targets of Msg5p revealed that kss1delta could suppress the osmosensitivity of pbs2-3. Kss1p is phosphorylated in response to hyperosmotic shock in a pbs2-3 strain, but not in a wild-type strain nor in a pbs2-3 strain overexpressing MSG5. Both TEC1 and FRE::lacZ expressions are activated in strains lacking a functional HOG pathway during osmotic stress in a filamentation/invasion-pathway-dependent manner. Additionally, the cellular projections formed by a pbs2-3 mutant on high osmolarity are absent in strains lacking KSS1 or STE7. These data suggest that the loss of filamentation/invasion pathway repression contributes to the HOG mutant phenotype. PMID:10545444

Hydrogen saline suppresses neuronal cell apoptosis and inhibits the p38 mitogen‑activated protein kinase‑caspase‑3 signaling pathway following cerebral ischemia‑reperfusion injury.

PubMed

Li, Da; Ai, Yanqiu

2017-10-01

Cerebral ischemia‑reperfusion injury (CIRI) is a serious pathological disease that is associated with a high rate death and disability. Saturated hydrogen (H2) saline exhibits brain protective functions through anti‑inflammatory, antioxidant and antiapoptotic effects. The present study investigated the potential treatment effects of H2 on CIRI. In addition, the potential protective mechanisms of H2 in the prevention of CIRI were investigated. Adult, male Sprague‑Dawley rats (n=60) were randomly divided into the following three groups: Sham‑operated group; IR group; and IR + H2 group (0.6 mmol/l, 0.5 ml/kg/day). Hematoxylin and eosin, and TUNEL staining were performed for histopathological analysis and investigation of apoptosis, respectively. In addition, the protein expression of caspase‑3, p38 mitogen‑activated protein kinase (MAPK) and phosphorylated‑p38 MAPK in the cortex were measured by western blotting analysis. These results demonstrated that H2 significantly reduced the number of apoptotic cells, and the protein expression of p38 MAPK and caspase‑3, compared with the IR group. These effects may be associated with the p38MAPK signaling pathway.

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. Copyright © 2016 Elsevier Inc. All rights reserved.

JWA gene regulates PANC-1 pancreatic cancer cell behaviors through MEK-ERK1/2 of the MAPK signaling pathway.

PubMed

Wu, Yuan-Yuan; Ma, Tie-Liang; Ge, Zhi-Jun; Lin, Jie; Ding, Wei-Liang; Feng, Jia-Ke; Zhou, Su-Jun; Chen, Guo-Chang; Tan, Yong-Fei; Cui, Guo-Xing

2014-10-01

The present study aimed to investigate the role of JWA gene in the proliferation, apoptosis, invasion and migration of PANC-1 pancreatic cancer cells and the effect on the MAPK signaling pathway. Human PANC-1 pancreatic cancer cells were cultured in vitro , and small interfering RNA (siRNA) was designed for the JWA gene. The siRNA was transfected into PANC-1 cells. Subsequently, the cell proliferation was measured by MTT assay; cell apoptosis was detected by analyzing BAX and Bcl-2 protein expression; cell migration and invasion were measured using Transwell ® chambers; and the protein expression of JWA and ERK1/2, JNK and p38 and their phosphorylated forms were measured by western blotting. By utilizing the MTT assay, the results showed that when JWA protein expression was inhibited, the proliferation of PANC-1 cells was enhanced. In addition, the expression of apoptosis-associated protein (AAP) BAX was substantially decreased, while the expression of the apoptosis inhibitor gene, Bcl-2 , was significantly enhanced. Using Transwell chambers, it was found that the number of penetrating PANC-1 cells was significantly increased after transfection with JWA siRNA, suggesting that the migration and invasion of the cells was substantially increased. By studying the association between JWA and the MAPK pathway in PANC-1 cells, it was found that the expression of p-ERK1/2 of the MAPK pathway was significantly downregulated following JWA siRNA transfection. However, the expression levels of ERK1/2, JNK, p38, p-JNK and p-p38 showed no significant differences. In conclusion, it was shown that JWA affects the proliferation, apoptosis, invasion and migration of PANC-1 pancreatic cancer cells which could be attributed to effects on the expression of ERK1/2 in the MAPK pathway.

Cigarette smoke-induced cell cycle arrest in spermatocytes [GC-2spd(ts)] is mediated through crosstalk between Ahr-Nrf2 pathway and MAPK signaling.

PubMed

Esakky, Prabagaran; Hansen, Deborah A; Drury, Andrea M; Moley, Kelle H

2015-02-01

Our earlier studies have demonstrated that the cigarette smoke in the form of cigarette smoke condensate (CSC) causes growth arrest of a mouse spermatocyte cell line [GC-2spd(ts)] through activation of the AHR-NRF2 pathway. The present study demonstrates the CSC-activated p38 and ERK MAPK signaling in GC-2spd(ts) via arylhydrocarbon receptor (AHR). Pharmacological inhibition by using AHR-antagonist, or p38 MAPK and ERK (MEK1) inhibitors significantly abrogates CSC-induced growth arrest by AHR and MAPK inactivation. QRT-PCR, western blot, and immunofluorescence of Ahr-target of Nrf2, and stress-inducible growth suppressive Atf3 and E2f4 following treatments indicate a crosstalk among these pathways. Regulation of Atf3 by Nrf2 and Ahr through RNA interference suggests the existence of a cross-regulatory loop between the targets. CSC induction of E2f4 via Atf3 and its regulation by pharmacological inhibitors reveal a possible regulatory mechanism of growth inhibitory CSC. SiRNA silencing of Ahr, Nrf2, Atf3, and E2f4 genes and downregulation of cyclins by CSC corroborate the growth inhibitory effect of cigarette smoke. Thus, the data obtained suggest that the CSC-mediated MAPKs and AHR-NRF2 crosstalks lay the molecular basis for the growth arrest and cell death of spermatocytes. © The Author (2014). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.

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

PubMed Central

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

2013-01-01

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

Docking, synthesis and pharmacological activity of novel urea-derivatives designed as p38 MAPK inhibitors.

PubMed

de Oliveira Lopes, Raquel; Romeiro, Nelilma Correia; de Lima, Cleverton Kleiton F; Louback da Silva, Leandro; de Miranda, Ana Luisa Palhares; Nascimento, Paulo Gustavo B D; Cunha, Fernando Q; Barreiro, Eliezer J; Lima, Lídia Moreira

2012-08-01

p38 mitogen-activated protein kinase (p38 MAPK) is an important signal transducing enzyme involved in many cellular regulations, including signaling pathways, pain and inflammation. Several p38 MAPK inhibitors have been developed as drug candidates to treatment of autoimmune disorders, such as rheumatoid arthritis. In this paper we reported the docking, synthesis and pharmacological activity of novel urea-derivatives (4a-e) designed as p38 MAPK inhibitors. These derivatives presented good theoretical affinity to the target p38 MAPK, standing out compound 4e (LASSBio-998), which showed a better score value compared to the prototype GK-00687. This compound was able to reduce in vitro TNF-α production and was orally active in a hypernociceptive murine model sensible to p38 MAPK inhibitors. Otherwise, compound 4e presented a dose-dependent analgesic effect in a model of antigen (mBSA)-induced arthritis and anti-inflammatory profile in carrageenan induced paw edema, indicating its potential as a new antiarthritis prototype. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

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

The mitogen-activated protein kinase (MAPK) cascade controls phosphatase and tensin homolog (PTEN) expression through multiple mechanisms.

PubMed

Ciuffreda, Ludovica; Di Sanza, Cristina; Cesta Incani, Ursula; Eramo, Adriana; Desideri, Marianna; Biagioni, Francesca; Passeri, Daniela; Falcone, Italia; Sette, Giovanni; Bergamo, Paola; Anichini, Andrea; Sabapathy, Kanaga; McCubrey, James A; Ricciardi, Maria Rosaria; Tafuri, Agostino; Blandino, Giovanni; Orlandi, Augusto; De Maria, Ruggero; Cognetti, Francesco; Del Bufalo, Donatella; Milella, Michele

2012-06-01

The mitogen-activated protein kinase (MAPK) and PI3K pathways are regulated by extensive crosstalk, occurring at different levels. In tumors, transactivation of the alternate pathway is a frequent "escape" mechanism, suggesting that combined inhibition of both pathways may achieve synergistic antitumor activity. Here we show that, in the M14 melanoma model, simultaneous inhibition of both MEK and mammalian target of rapamycin (mTOR) achieves synergistic effects at suboptimal concentrations, but becomes frankly antagonistic in the presence of relatively high concentrations of MEK inhibitors. This observation led to the identification of a novel crosstalk mechanism, by which either pharmacologic or genetic inhibition of constitutive MEK signaling restores phosphatase and tensin homolog (PTEN) expression, both in vitro and in vivo, and inhibits downstream signaling through AKT and mTOR, thus bypassing the need for double pathway blockade. This appears to be a general regulatory mechanism and is mediated by multiple mechanisms, such as MAPK-dependent c-Jun and miR-25 regulation. Finally, PTEN upregulation appears to be a major effector of MEK inhibitors' antitumor activity, as cancer cells in which PTEN is inactivated are consistently more resistant to the growth inhibitory and anti-angiogenic effects of MEK blockade.

Collagen-derived N-acetylated proline-glycine-proline upregulates the expression of pro-inflammatory cytokines and extracellular matrix proteases in nucleus pulposus cells via the NF-κB and MAPK signaling pathways.

PubMed

Feng, Chencheng; He, Jinyue; Zhang, Yang; Lan, Minghong; Yang, Minghui; Liu, Huan; Huang, Bo; Pan, Yong; Zhou, Yue

2017-07-01

N-acetylated proline-glycine-proline (N-Ac-PGP) is a chemokine involved in inflammatory diseases and is found to accumulate in degenerative discs. N-Ac-PGP has been demonstrated to have a pro-inflammatory effect on human cartilage endplate stem cells. However, the effect of N-Ac-PGP on human intervertebral disc cells, especially nucleus pulposus (NP) cells, remains unknown. The purpose of this study was to investigate the effect of N-Ac-PGP on the expression of pro-inflammatory factors and extracellular matrix (ECM) proteases in NP cells and the molecular mechanism underlying this effect. Therefore, Milliplex assays were used to detect the levels of various inflammatory cytokines in conditioned culture medium of NP cells treated with N-Ac-PGP, including interleukin-1β (IL-1β), IL-6, IL-17, tumor necrosis factor-α (TNF-α) and C-C motif ligand 2 (CCL2). RT-qPCR was also used to determine the expression of pro-inflammatory cytokines and ECM proteases in the NP cells treated with N-Ac-PGP. Moreover, the role of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways in mediating the effect of N-Ac-PGP on the phenotype of NP cells was investigated using specific signaling inhibitors. Milliplex assays showed that NP cells treated with N-Ac-PGP (10 and 100 µg/ml) secreted higher levels of IL-1β, IL-6, IL-17, TNF-α and CCL2 compared with the control. RT-qPCR assays showed that NP cells treated with N-Ac-PGP (100 µg/ml) had markedly upregulated expression of matrix metalloproteinase 3 (MMP3), MMP13, a disintegrin and metalloproteinase with thrombospondin motif 4 (ADAMTS4), ADAMTS5, IL-6, CCL-2, CCL-5 and C-X-C motif chemokine ligand 10 (CXCL10). Moreover, N-Ac-PGP was shown to activate the MAPK and NF-κB signaling pathways in NP cells. MAPK and NF-κB signaling inhibitors suppressed the upregulation of proteases and pro-inflammatory cytokines in NP cells treated with N-Ac-PGP. In conclusion, N-Ac-PGP induces the expression of pro-inflammatory cytokines and matrix catabolic enzymes in NP cells via the NF-κB and MAPK signaling pathways. N-Ac-PGP is a novel therapeutic target for intervertebral disc degeneration.

Integrating patterning signals: Wnt/GSK3 regulates the duration of the BMP/Smad1 signal.

PubMed

Fuentealba, Luis C; Eivers, Edward; Ikeda, Atsushi; Hurtado, Cecilia; Kuroda, Hiroki; Pera, Edgar M; De Robertis, Edward M

2007-11-30

BMP receptors determine the intensity of BMP signals via Smad1 C-terminal phosphorylations. Here we show that a finely controlled cell biological pathway terminates this activity. The duration of the activated pSmad1(Cter) signal was regulated by sequential Smad1 linker region phosphorylations at conserved MAPK and GSK3 sites required for its polyubiquitinylation and transport to the centrosome. Proteasomal degradation of activated Smad1 and total polyubiquitinated proteins took place in the centrosome. Inhibitors of the Erk, p38, and JNK MAPKs, as well as GSK3 inhibitors, prolonged the duration of a pulse of BMP7. Wnt signaling decreased pSmad1(GSK3) antigen levels and redistributed it from the centrosome to cytoplasmic LRP6 signalosomes. In Xenopus embryos, it was found that Wnts induce epidermis and that this required an active BMP-Smad pathway. Epistatic experiments suggested that the dorsoventral (BMP) and anteroposterior (Wnt/GSK3) patterning gradients are integrated at the level of Smad1 phosphorylations during embryonic pattern formation.

Meta-Analysis of Global Transcriptomics Suggests that Conserved Genetic Pathways are Responsible for Quercetin and Tannic Acid Mediated Longevity in C. elegans

PubMed Central

Pietsch, Kerstin; Saul, Nadine; Swain, Suresh C.; Menzel, Ralph; Steinberg, Christian E. W.; Stürzenbaum, Stephen R.

2012-01-01

Recent research has highlighted that the polyphenols Quercetin and Tannic acid are capable of extending the lifespan of Caenorhabditis elegans. To gain a deep understanding of the underlying molecular genetics, we analyzed the global transcriptional patterns of nematodes exposed to three concentrations of Quercetin or Tannic acid, respectively. By means of an intricate meta-analysis it was possible to compare the transcriptomes of polyphenol exposure to recently published datasets derived from (i) longevity mutants or (ii) infection. This detailed comparative in silico analysis facilitated the identification of compound specific and overlapping transcriptional profiles and allowed the prediction of putative mechanistic models of Quercetin and Tannic acid mediated longevity. Lifespan extension due to Quercetin was predominantly driven by the metabolome, TGF-beta signaling, Insulin-like signaling, and the p38 MAPK pathway and Tannic acid’s impact involved, in part, the amino acid metabolism and was modulated by the TGF-beta and the p38 MAPK pathways. DAF-12, which integrates TGF-beta and Insulin-like downstream signaling, and genetic players of the p38 MAPK pathway therefore seem to be crucial regulators for both polyphenols. Taken together, this study underlines how meta-analyses can provide an insight of molecular events that go beyond the traditional categorization into gene ontology-terms and Kyoto encyclopedia of genes and genomes-pathways. It also supports the call to expand the generation of comparative and integrative databases, an effort that is currently still in its infancy. PMID:22493606

RSK regulates activated BRAF signalling to mTORC1 and promotes melanoma growth

PubMed Central

Zindy, Pierre-Joachim; Saba-El-Leil, Marc; Lavoie, Geneviève; Dandachi, Farah; Baptissart, Marine; Borden, Katherine L. B.; Meloche, Sylvain; Roux, Philippe P.

2015-01-01

The Ras/mitogen-activated protein kinase (MAPK) signalling cascade regulates various biological functions, including cell growth, proliferation and survival. As such, this pathway is often deregulated in cancer, including melanomas, which frequently harbour activating mutations in the NRAS and BRAF oncogenes. Hyperactive MAPK signalling is known to promote protein synthesis, but the mechanisms by which this occurs remain poorly understood. Here, we show that expression of oncogenic forms of Ras and Raf promotes the constitutive activation of the mammalian target of rapamycin (mTOR). Using pharmacological inhibitors and RNA interference we find that the MAPK-activated protein kinase RSK (p90 ribosomal S6 kinase) is partly required for these effects. Using melanoma cell lines carrying activating BRAF mutations we show that ERK/RSK signalling regulates assembly of the translation initiation complex and polysome formation, as well as the translation of growth-related mRNAs containing a 5’ terminal oligopyrimidine (TOP) motif. Accordingly, we find that RSK inhibition abrogates tumour growth in mice. Our findings indicate that RSK may be a valuable therapeutic target for the treatment of tumours characterized by deregulated MAPK signalling, such as melanoma. PMID:22797077

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

PubMed Central

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

2014-01-01

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

Schwann Cell Migration Induced by Earthworm Extract via Activation of PAs and MMP2/9 Mediated through ERK1/2 and p38

PubMed Central

Chang, Yung-Ming; Shih, Ying-Ting; Chen, Yueh-Sheng; Liu, Chien-Liang; Fang, Wen-Kuei; Tsai, Chang-Hai; Tsai, Fuu-Jen; Kuo, Wei-Wen; Lai, Tung-Yuan; Huang, Chih-Yang

2011-01-01

The earthworm, which has stasis removal and wound-healing functions, is a widely used Chinese herbal medicine in China. Schwann cell migration is critical for the regeneration of injured nerves. Schwann cells provide an essentially supportive activity for neuron regeneration. However, the molecular migration mechanisms induced by earthworms in Schwann cells remain unclear. Here, we investigate the roles of MAPK (ERK1/2, JNK and p38) pathways for earthworm-induced matrix-degrading proteolytic enzyme (PAs and MMP2/9) production in Schwann cells. Moreover, earthworm induced phosphorylation of ERK1/2 and p38, but not JNK, activate the downstream signaling expression of PAs and MMPs in a time-dependent manner. Earthworm-stimulated ERK1/2 and p38 phosphorylation was attenuated by pretreatment with U0126 and SB203580, resulting in migration and uPA-related signal pathway inhibition. The results were confirmed using small interfering ERK1/2 and p38 RNA. These results demonstrated that earthworms can stimulate Schwann cell migration and up-regulate PAs and MMP2/9 expression mediated through the MAPK pathways, ERK1/2 and p38. Taken together, our data suggests the MAPKs (ERK1/2, p38)-, PAs (uPA, tPA)-, MMP (MMP2, MMP9) signaling pathway of Schwann cells regulated by earthworms might play a major role in Schwann cell migration and nerve regeneration. PMID:19808845

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

PubMed

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

2017-07-11

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

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

PubMed Central

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

2013-01-01

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

Effects of Germline Mutations in the Ras/MAPK Signaling Pathway on Adaptive Behavior: Cardiofaciocutaneous Syndrome and Noonan Syndrome

PubMed Central

Pierpont, Elizabeth I.; Pierpont, Mary Ella; Mendelsohn, Nancy J.; Roberts, Amy E.; Tworog-Dube, Erica; Rauen, Katherine A.; Seidenberg, Mark S.

2011-01-01

Cardiofaciocutaneous syndrome (CFC) and Noonan syndrome (NS) are two phenotypically overlapping genetic disorders whose underlying molecular etiologies affect a common signaling pathway. Mutations in the BRAF, MEK1 and MEK2 genes cause most cases of CFC and mutations in PTPN11, SOS1, KRAS and RAF1 typically cause NS. Although both syndromes are associated with developmental delays of varying severity, the extent to which the behavioral profiles differ may shed light on the different roles these respective genes play in development of skills necessary for everyday functioning. In this study, profiles of adaptive behavior of individuals with CFC and NS who had confirmed pathogenic mutations in Ras/MAPK pathway genes were investigated. Patterns of strengths and weaknesses, age-related differences, and risk factors for difficulties in adaptive skills were assessed. Although genes acting more downstream in the Ras/MAPK pathway were associated with more difficulties in adaptive functioning than genes more upstream in the pathway, several inconsistencies highlight the wide spectrum of possible developmental courses in CFC and NS. Along with clinical and genetic factors, variables such as chronological age, gestational age at birth and parental education levels accounted for significant variance in adaptive skills. Results indicate that there is wide heterogeneity in adaptive ability in CFC and NS, but that these abilities are correlated to some extent with the specific disease-causing genes. PMID:20186801

An intracellular signaling hierarchy determines direction of migration in opposing chemotactic gradients.

PubMed

Heit, Bryan; Tavener, Samantha; Raharjo, Eko; Kubes, Paul

2002-10-14

Neutrophils must follow both endogenous and bacterial chemoattractant signals out of the vasculature and through the interstitium to arrive at a site of infection. By necessity, in the setting of multiple chemoattractants, the neutrophils must prioritize, favoring end target chemoattractants (e.g., fMLP and C5a) emanating from the site of infection over intermediary endogenous chemoattractants (e.g., IL-8 and LTB4) encountered en route to sites of infection. In this study, we propose a hierarchical model of two signaling pathways mediating the decision-making process of the neutrophils, which allows end target molecules to dominate over intermediary chemoattractants. In an under agarose assay, neutrophils predominantly migrated toward end target chemoattractants via p38 MAPK, whereas intermediary chemoattractant-induced migration was phosphoinositide 3-kinase (PI3K)/Akt dependent. When faced with competing gradients of end target and intermediary chemoattractants, Akt activation was significantly reduced within neutrophils, and the cells migrated preferentially toward end target chemoattractants even at 1/1,000th that of intermediary chemoattractants. End target molecules did not require chemotactic properties, since the p38 MAPK activator, LPS, also inhibited Akt and prevented migration to intermediary chemoattractants. p38 MAPK inhibitors not only reversed this hierarchy, such that neutrophils migrated preferentially toward intermediary chemoattractants, but also allowed neutrophils to be drawn out of a local end target chemoattractant environment and toward intermediary chemoattractants unexpectedly in an exaggerated (two- to fivefold) fashion. This was entirely related to significantly increased magnitude and duration of Akt activation. Finally, end target chemoattractant responses were predominantly Mac-1 dependent, whereas nondominant chemoattractants used primarily LFA-1. These data provide support for a two pathway signaling model wherein the end target chemoattractants activate p38 MAPK, which inhibits intermediary chemoattractant-induced PI3K/Akt pathway, establishing an intracellular signaling hierarchy.

Dual p38/JNK Mitogen Activated Protein Kinase Inhibitors Prevent Ozone-Induced Airway Hyperreactivity in Guinea Pigs

PubMed Central

Verhein, Kirsten C.; Salituro, Francesco G.; Ledeboer, Mark W.; Fryer, Allison D.; Jacoby, David B.

2013-01-01

Ozone exposure causes airway hyperreactivity and increases hospitalizations resulting from pulmonary complications. Ozone reacts with the epithelial lining fluid and airway epithelium to produce reactive oxygen species and lipid peroxidation products, which then activate cell signaling pathways, including the mitogen activated protein kinase (MAPK) pathway. Both p38 and c-Jun NH2 terminal kinase (JNK) are MAPK family members that are activated by cellular stress and inflammation. To test the contribution of both p38 and JNK MAPK to ozone-induced airway hyperreactivity, guinea pigs were pretreated with dual p38 and JNK MAPK inhibitors (30 mg/kg, ip) 60 minutes before exposure to 2 ppm ozone or filtered air for 4 hours. One day later airway reactivity was measured in anesthetized animals. Ozone caused airway hyperreactivity one day post-exposure, and blocking p38 and JNK MAPK completely prevented ozone-induced airway hyperreactivity. Blocking p38 and JNK MAPK also suppressed parasympathetic nerve activity in air exposed animals, suggesting p38 and JNK MAPK contribute to acetylcholine release by airway parasympathetic nerves. Ozone inhibited neuronal M2 muscarinic receptors and blocking both p38 and JNK prevented M2 receptor dysfunction. Neutrophil influx into bronchoalveolar lavage was not affected by MAPK inhibitors. Thus p38 and JNK MAPK mediate ozone-induced airway hyperreactivity through multiple mechanisms including prevention of neuronal M2 receptor dysfunction. PMID:24058677

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.

Downstream components of RhoA required for signal pathway of superoxide formation during phagocytosis of serum opsonized zymosans in macrophages.

PubMed

Kim, Jun Sub; Kim, Jae Gyu; Jeon, Chan Young; Won, Ha Young; Moon, Mi Young; Seo, Ji Yeon; Kim, Jong Il; Kim, Jaebong; Lee, Jae Yong; Choi, Soo Young; Park, Jinseu; Yoon Park, Jung Han; Ha, Kwon Soo; Kim, Pyeung Hyeun; Park, Jae Bong

2005-12-31

Rac1 and Rac2 are essential for the control of oxidative burst catalyzed by NADPH oxidase. It was also documented that Rho is associated with the superoxide burst reaction during phagocytosis of serum- (SOZ) and IgG-opsonized zymosan particles (IOZ). In this study, we attempted to reveal the signal pathway components in the superoxide formation regulated by Rho GTPase. Tat-C3 blocked superoxide production, suggesting that RhoA is essentially involved in superoxide formation during phagocytosis of SOZ. Conversely SOZ activated both RhoA and Rac1/2. Inhibition of RhoA-activated kinase (ROCK), an important downstream effector of RhoA, by Y27632 and myosin light chain kinase (MLCK) by ML-7 abrogated superoxide production by SOZ. Extracellular signaling-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase (MAPK) were activated during phagocytosis of SOZ, and Tat-C3 and SB203580 reduced ERK1/2 and p38 MAPK activation, suggesting that RhoA and p38 MAPK may be upstream regulators of ERK1/2. Inhibition of ERK1/2, p38 MAPK, phosphatidyl inositol 3-kinase did not block translocation of RhoA to membranes, suggesting that RhoA is upstream to these kinases. Inhibition of RhoA by Tat-C3 blocked phosphorylation of p47(PHOX). Taken together, RhoA, ROCK, p38MAPK, ERK1/2, and p47(PHOX) may be subsequently activated, leading to activation of NADPH oxidase to produce superoxide.

Comprehensive Ex Vivo Transposon Mutagenesis Identifies Genes That Promote Growth Factor Independence and Leukemogenesis.

PubMed

Guo, Yabin; Updegraff, Barrett L; Park, Sunho; Durakoglugil, Deniz; Cruz, Victoria H; Maddux, Sarah; Hwang, Tae Hyun; O'Donnell, Kathryn A

2016-02-15

Aberrant signaling through cytokine receptors and their downstream signaling pathways is a major oncogenic mechanism underlying hematopoietic malignancies. To better understand how these pathways become pathologically activated and to potentially identify new drivers of hematopoietic cancers, we developed a high-throughput functional screening approach using ex vivo mutagenesis with the Sleeping Beauty transposon. We analyzed over 1,100 transposon-mutagenized pools of Ba/F3 cells, an IL3-dependent pro-B-cell line, which acquired cytokine independence and tumor-forming ability. Recurrent transposon insertions could be mapped to genes in the JAK/STAT and MAPK pathways, confirming the ability of this strategy to identify known oncogenic components of cytokine signaling pathways. In addition, recurrent insertions were identified in a large set of genes that have been found to be mutated in leukemia or associated with survival, but were not previously linked to the JAK/STAT or MAPK pathways nor shown to functionally contribute to leukemogenesis. Forced expression of these novel genes resulted in IL3-independent growth in vitro and tumorigenesis in vivo, validating this mutagenesis-based approach for identifying new genes that promote cytokine signaling and leukemogenesis. Therefore, our findings provide a broadly applicable approach for classifying functionally relevant genes in diverse malignancies and offer new insights into the impact of cytokine signaling on leukemia development. ©2015 American Association for Cancer Research.

The Core Molecular Machinery Used for Engulfment of Apoptotic Cells Regulates the JNK Pathway Mediating Axon Regeneration in Caenorhabditis elegans.

PubMed

Pastuhov, Strahil Iv; Fujiki, Kota; Tsuge, Anna; Asai, Kazuma; Ishikawa, Sho; Hirose, Kazuya; Matsumoto, Kunihiro; Hisamoto, Naoki

2016-09-14

The mechanisms that govern the ability of specific neurons to regenerate their axons after injury are not well understood. In Caenorhabditis elegans, the initiation of axon regeneration is positively regulated by the JNK-MAPK pathway. In this study, we identify two components functioning upstream of the JNK pathway: the Ste20-related protein kinase MAX-2 and the Rac-type GTPase CED-10. CED-10, when bound by GTP, interacts with MAX-2 and functions as its upstream regulator in axon regeneration. CED-10, in turn, is activated by axon injury via signals initiated from the integrin α-subunit INA-1 and the nonreceptor tyrosine kinase SRC-1 and transmitted via the signaling module CED-2/CrkII-CED-5/Dock180-CED-12/ELMO. This module is also known to regulate the engulfment of apoptotic cells during development. Our findings thus reveal that the molecular machinery used for engulfment of apoptotic cells also promotes axon regeneration through activation of the JNK pathway. The molecular mechanisms of axon regeneration after injury remain poorly understood. In Caenorhabditis elegans, the initiation of axon regeneration is positively regulated by the JNK-MAPK pathway. In this study, we show that integrin, Rac-GTPase, and several other molecules, all of which are known to regulate engulfment of apoptotic cells during development, also regulate axon regeneration. This signaling module activates the JNK-MAPK cascade via MAX-2, a PAK-like protein kinase that binds Rac. Our findings thus reveal that the molecular machinery used for engulfment of apoptotic cells also promotes axon regeneration through activation of the JNK pathway. Copyright © 2016 the authors 0270-6474/16/369710-12$15.00/0.

Luteinizing hormone stimulates mammalian target of rapamycin signaling in bovine luteal cells via pathways independent of AKT and mitogen-activated protein kinase: modulation of glycogen synthase kinase 3 and AMP-activated protein kinase.

PubMed

Hou, Xiaoying; Arvisais, Edward W; Davis, John S

2010-06-01

LH stimulates the production of cAMP in luteal cells, which leads to the production of progesterone, a hormone critical for the maintenance of pregnancy. The mammalian target of rapamycin (MTOR) signaling cascade has recently been examined in ovarian follicles where it regulates granulosa cell proliferation and differentiation. This study examined the actions of LH on the regulation and possible role of the MTOR signaling pathway in primary cultures of bovine corpus luteum cells. Herein, we demonstrate that activation of the LH receptor stimulates the phosphorylation of the MTOR substrates ribosomal protein S6 kinase 1 (S6K1) and eukaryotic translation initiation factor 4E binding protein 1. The actions of LH were mimicked by forskolin and 8-bromo-cAMP. LH did not increase AKT or MAPK1/3 phosphorylation. Studies with pathway-specific inhibitors demonstrated that the MAPK kinase 1 (MAP2K1)/MAPK or phosphatidylinositol 3-kinase/AKT signaling pathways were not required for LH-stimulated MTOR/S6K1 activity. However, LH decreased the activity of glycogen synthase kinase 3Beta (GSK3B) and AMP-activated protein kinase (AMPK). The actions of LH on MTOR/S6K1 were mimicked by agents that modulated GSK3B and AMPK activity. The ability of LH to stimulate progesterone secretion was not prevented by rapamycin, a MTOR inhibitor. In contrast, activation of AMPK inhibited LH-stimulated MTOR/S6K1 signaling and progesterone secretion. In summary, the LH receptor stimulates a unique series of intracellular signals to activate MTOR/S6K1 signaling. Furthermore, LH-directed changes in AMPK and GSK3B phosphorylation appear to exert a greater impact on progesterone synthesis in the corpus luteum than rapamycin-sensitive MTOR-mediated events.

New Insights from Drosophila into the Regulation of EGFR Signaling.

PubMed

Harden, Nicholas

2017-01-01

Genetic analysis of Egfr signaling in Drosophila has a long-standing track record of making important contributions to our understanding of the Egfr pathway. While the central Ras/MAPK pathway has long been well defined, there is much to learn with regard to its cross talk with other pathways and how it is regulated. A better understanding of the regulation of Egfr signaling is of particular interest with regard to the participation of misregulated Egfr signaling in tumorigenesis. Recent studies in the fly have led to some surprising results, identifying regulators of Egfr acting in unexpected ways.

Phloretin ameliorates chemokines and ICAM-1 expression via blocking of the NF-κB pathway in the TNF-α-induced HaCaT human keratinocytes.

PubMed

Huang, Wen-Chung; Dai, Yi-Wen; Peng, Hui-Ling; Kang, Chiao-Wei; Kuo, Chun-Yu; Liou, Chian-Jiun

2015-07-01

Previous studies found that phloretin had anti-oxidant, anti-inflammatory, and anti-tumor properties. In this study, we investigated whether phloretin could suppress the production of the intercellular adhesion molecule (ICAM)-1 and chemokines through downregulation of the nuclear transcription factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways in TNF-α-stimulated HaCaT human keratinocytes. HaCaT cells were treated with phloretin and then the cells were stimulated by TNF-α. Phloretin treatment decreased the production of IL-6, IL-8, CCL5, MDC, and TARC. Phloretin decreased ICAM-1 protein and mRNA expression, and also suppressed the adhesion of monocyte THP-1 cells to inflammatory HaCaT cells. Phloretin inhibited NF-κB translocation into the nucleus and also suppressed the phosphorylation of Akt and MAPK signal. In addition, phloretin increased heme oxygenase-1 production in a concentration-dependent manner. These results demonstrated that phloretin has anti-inflammatory effects to inhibit chemokines and ICAM-1 expressions through suppression of the NF-κB and MAPK pathways in human keratinocytes. Copyright © 2015 Elsevier B.V. All rights reserved.

WNK4 inhibits NCC protein expression through MAPK ERK1/2 signaling pathway.

PubMed

Zhou, Bo; Wang, Dexuan; Feng, Xiuyan; Zhang, Yiqian; Wang, Yanhui; Zhuang, Jieqiu; Zhang, Xuemei; Chen, Guangping; Delpire, Eric; Gu, Dingying; Cai, Hui

2012-03-01

WNK [with no lysine (K)] kinase is a subfamily of serine/threonine kinases. Mutations in two members of this family (WNK1 and WNK4) cause pseudohypoaldosteronism type II featuring hypertension, hyperkalemia, and metabolic acidosis. WNK1 and WNK4 were shown to regulate sodium chloride cotransporter (NCC) activity through phosphorylating SPAK and OSR1. Previous studies including ours have also shown that WNK4 inhibits NCC function and its protein expression. A recent study reported that a phorbol ester inhibits NCC function via activation of extracellular signal-regulated kinase (ERK) 1/2 kinase. In the current study, we investigated whether WNK4 affects NCC via the MAPK ERK1/2 signaling pathway. We found that WNK4 increased ERK1/2 phosphorylation in a dose-dependent manner in mouse distal convoluted tubule (mDCT) cells, whereas WNK4 mutants with the PHA II mutations (E562K and R1185C) lost the ability to increase the ERK1/2 phosphorylation. Hypertonicity significantly increased ERK1/2 phosphorylation in mDCT cells. Knock-down of WNK4 expression by siRNA resulted in a decrease of ERK1/2 phosphorylation. We further showed that WNK4 knock-down significantly increases the cell surface and total NCC protein expressions and ERK1/2 knock-down also significantly increases cell surface and total NCC expression. These data suggest that WNK4 inhibits NCC through activating the MAPK ERK1/2 signaling pathway.

Design and synthesis of formononetin-dithiocarbamate hybrids that inhibit growth and migration of PC-3 cells via MAPK/Wnt signaling pathways

PubMed Central

Fu, Dong-Jun; Zhang, Li; Song, Jian; Mao, Ruo-Wang; Zhao, Ruo-Han; Liu, Ying-Chao; Hou, Yu-Hui; Li, Jia-Huan; Yang, Jia-Jia; Jin, Cheng-Yun; Li, Ping; Zi, Xiao-Lin; Liu, Hong-Min; Zhang, Sai-Yang; Zhang, Yan-Bing

2017-01-01

A series of novel formononetin-dithiocarbamate derivatives were designed, synthesized and evaluated for antiproliferative activity against three selected cancer cell line (MGC-803, EC-109, PC-3). The first structure-activity relationship (SAR) for this formononetin-dithiocarbamate scaffold is explored in this report with evaluation of 14 variants of the structural class. Among these analogues, tert-butyl 4-(((3-((3-(4-methoxyphenyl)-4-oxo-4H–chromen-7-yl)oxy)propyl)thio)carbonothioyl)piperazine-1-carboxylate (8i) showed the best inhibitory activity against PC-3 cells (IC50 = 1. 97 µM). Cellular mechanism studies elucidated 8i arrests cell cycle at G1 phase and regulates the expression of G1 checkpoint-related proteins in concentration-dependent manners. Furthermore, 8i could inhibit cell growth via MAPK signaling pathway and inhibit migration via Wnt pathway in PC-3 cells. PMID:28038329

Therapeutic targeting of the MEK/MAPK signal transduction module in acute myeloid leukemia

PubMed Central

Milella, Michele; Kornblau, Steven M.; Estrov, Zeev; Carter, Bing Z.; Lapillonne, Hélène; Harris, David; Konopleva, Marina; Zhao, Shourong; Estey, Elihu; Andreeff, Michael

2001-01-01

The mitogen-activated protein kinase (MAPK) pathway regulates growth and survival of many cell types, and its constitutive activation has been implicated in the pathogenesis of a variety of malignancies. In this study we demonstrate that small-molecule MEK inhibitors (PD98059 and PD184352) profoundly impair cell growth and survival of acute myeloid leukemia (AML) cell lines and primary samples with constitutive MAPK activation. These agents abrogate the clonogenicity of leukemic cells but have minimal effects on normal hematopoietic progenitors. MEK blockade also results in sensitization to spontaneous and drug-induced apoptosis. At a molecular level, these effects correlate with modulation of the expression of cyclin-dependent kinase inhibitors (p27Kip1 and p21Waf1/CIP1) and antiapoptotic proteins of the inhibitor of apoptosis proteins (IAP) and Bcl-2 families. Interruption of constitutive MEK/MAPK signaling therefore represents a promising therapeutic strategy in AML. PMID:11560954

Five Xanthomonas type III effectors suppress cell death induced by components of immunity-associated MAP kinase cascades

PubMed Central

Teper, Doron; Sunitha, Sukumaran; Martin, Gregory B; Sessa, Guido

2015-01-01

Mitogen-activated protein kinase (MAPK) cascades play a fundamental role in signaling of plant immunity and mediate elicitation of cell death. Xanthomonas spp. manipulate plant signaling by using a type III secretion system to deliver effector proteins into host cells. We examined the ability of 33 Xanthomonas effectors to inhibit cell death induced by overexpression of components of MAPK cascades in Nicotiana benthamiana plants. Five effectors inhibited cell death induced by overexpression of MAPKKKα and MEK2, but not of MAP3Kϵ. In addition, expression of AvrBs1 in yeast suppressed activation of the high osmolarity glycerol MAPK pathway, suggesting that the target of this effector is conserved in eukaryotic organisms. These results indicate that Xanthomonas employs several type III effectors to suppress immunity-associated cell death mediated by MAPK cascades. PMID:26237448

A Unique Fungal Two-Component System Regulates Stress Responses, Drug Sensitivity, Sexual Development, and Virulence of Cryptococcus neoformans

PubMed Central

Bahn, Yong-Sun; Kojima, Kaihei; Cox, Gary M.

2006-01-01

The stress-activated mitogen-activated protein kinase (MAPK) pathway is widely used by eukaryotic organisms as a central conduit via which cellular responses to the environment effect growth and differentiation. The basidiomycetous human fungal pathogen Cryptococcus neoformans uniquely uses the stress-activated Pbs2-Hog1 MAPK system to govern a plethora of cellular events, including stress responses, drug sensitivity, sexual reproduction, and virulence. Here, we characterized a fungal “two-component” system that controls these fundamental cellular functions via the Pbs2-Hog1 MAPK cascade. A typical response regulator, Ssk1, modulated all Hog1-dependent phenotypes by controlling Hog1 phosphorylation, indicating that Ssk1 is the major upstream signaling component of the Pbs2-Hog1 pathway. A second response regulator, Skn7, governs sensitivity to Na+ ions and the antifungal agent fludioxonil, negatively controls melanin production, and functions independently of Hog1 regulation. To control these response regulators, C. neoformans uses multiple sensor kinases, including two-component–like (Tco) 1 and Tco2. Tco1 and Tco2 play shared and distinct roles in stress responses and drug sensitivity through the Hog1 MAPK system. Furthermore, each sensor kinase mediates unique cellular functions for virulence and morphological differentiation. Our findings highlight unique adaptations of this global two-component MAPK signaling cascade in a ubiquitous human fungal pathogen. PMID:16672377

Paclitaxel suppresses proliferation and induces apoptosis through regulation of ROS and the AKT/MAPK signaling pathway in canine mammary gland tumor cells.

PubMed

Ren, Xiaoli; Zhao, Bingbing; Chang, Hongjian; Xiao, Min; Wu, Yuhong; Liu, Yun

2018-06-01

Paclitaxel is a diterpenoid compound, derived from the pacific yew (Taxus brevifolia) berry, which exhibits antineoplastic effects against various types of cancer. However, the antitumor effects and the molecular mechanisms of paclitaxel on canine CHMm cells remain to be elucidated. The aim of the present study was to investigate the antitumor effects of paclitaxel on CHMm cells and identify relevant signal transduction pathways modulated by paclitaxel using multiple methods including MTT assay, flow cytometry, acridine orange/ethidium bromide staining, transmission electron microscopy, determination of cellular reactive oxygen species (ROS), superoxide dismutase (SOD) and malondiadehyde (MDA) and western blotting, the data indicated that paclitaxel decreased cell viability, induced G2/M‑phase cell cycle arrest, suppressed the expression of cyclin B1 and induced apoptosis in a dose‑dependent manner. In addition, paclitaxel upregulated the expression of Bax and cytochrome c, but reduced expression of apoptosis regulator Bcl‑2, resulting in activation of caspase‑3, chromatin condensation, karyopyknosis, intracellular vacuolization, increased production of ROS and MDA, and decreased activity of SOD. However, these effects were inhibited when CHMm cells were treated with N‑acetyl‑L‑cysteine. Furthermore, treatment with paclitaxel inhibited the level of of phospho (p)‑RAC‑α serine/threonine‑protein kinase (AKT) and p‑ribosomal protein S6 kinase proteins, and promoted phosphorylation of P38 mitogen‑activated protein kinase (MAPK) and p‑90 kDa ribosomal protein S6 kinase 1 proteins in CHMm cells. It was observed that paclitaxel in combination with pharmacological inhibitors of the P38 and phosphatidylinositol‑4,5‑bisphosphate 3‑kinase (PI3K) signaling pathways (SB203580 and LY294002, respectively) exerted synergistic inhibitory effects on the proliferation of the CHMm cells. The results of the present study demonstrated that paclitaxel inhibited tumor cell proliferation by increasing intrinsic apoptosis through inhibition of the PI3K/AKT signaling pathway and activation of MAPK signaling pathway in CHMm cells.

VEGF isoforms have differential effects on permeability of human pulmonary microvascular endothelial cells.

PubMed

Ourradi, Khadija; Blythe, Thomas; Jarrett, Caroline; Barratt, Shaney L; Welsh, Gavin I; Millar, Ann B

2017-06-02

Alternative splicing of Vascular endothelial growth factor-A mRNA transcripts (commonly referred as VEGF) leads to the generation of functionally differing isoforms, the relative amounts of which have potentially significant physiological outcomes in conditions such as acute respiratory distress syndrome (ARDS). The effect of such isoforms on pulmonary vascular permeability is unknown. We hypothesised that VEGF 165 a and VEGF 165 b isoforms would have differing effects on pulmonary vascular permeability caused by differential activation of intercellular signal transduction pathways. To test this hypothesis we investigated the physiological effect of VEGF 165 a and VEGF 165 b on Human Pulmonary Microvascular Endothelial Cell (HPMEC) permeability using three different methods: trans-endothelial electrical resistance (TEER), Electric cell-substrate impedance sensing (ECIS) and FITC-BSA passage. In addition, potential downstream signalling pathways of the VEGF isoforms were investigated by Western blotting and the use of specific signalling inhibitors. VEGF 165 a increased HPMEC permeability using all three methods (paracellular and transcellular) and led to associated VE-cadherin and actin stress fibre changes. In contrast, VEGF 165 b decreased paracellular permeability and did not induce changes in VE-cadherin cell distribution. Furthermore, VEGF 165 a and VEGF 165 b had differing effects on both the phosphorylation of VEGF receptors and downstream signalling proteins pMEK, p42/44MAPK, p38 MAPK, pAKT and peNOS. Interestingly specific inhibition of the pMEK, p38 MAPK, PI3 kinase and eNOS pathways blocked the effects of both VEGF 165 a and VEGF 165 b on paracellular permeability and the effect of VEGF 165 a on proliferation/migration, suggesting that this difference in cellular response is mediated by an as yet unidentified signalling pathway(s). This study demonstrates that the novel isoform VEGF 165 a and VEGF 165 b induce differing effects on permeability in pulmonary microvascular endothelial cells.

Effect of β-glucan on MUC4 and MUC5B expression in human airway epithelial cells.

PubMed

Kim, Yong-Dae; Bae, Chang Hoon; Song, Si-Youn; Choi, Yoon Seok

2015-08-01

β-Glucan is found in the cell walls of fungi, bacteria, and some plant tissues, and is detected by the innate immune system. Furthermore, this recognition is known to worsen respiratory symptoms in patients with allergic and inflammatory airway diseases. However, the means by which β-glucan affects the secretion of major mucins by human airway epithelial cells has not been elucidated. Therefore, in this study, the effect and signaling pathway of β-glucan on mucins MUC4 and MUC5B were investigated in human airway epithelial cells. In NCI-H292 cells and human normal nasal epithelial cells, the effect and signaling pathway of β-glucan on MUC4 and MUC5B expression were investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR, enzyme immunoassay, and immunoblot analysis with specific inhibitors and small interfering RNA (siRNA). β-Glucan increased MUC4 and MUC5B expression and activated the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). SB203580 (a p38 MAPK inhibitor) and pyrrolidine dithiocarbamate (PDTC; a NF-κB inhibitor) inhibited β-glucan-induced MUC4 and MUC5B expression. In addition, siRNA knockdown of p38 MAPK blocked β-glucan-induced MUC4 and MUC5B mRNA expression and β-glucan-activated phosphorylation of NF-κB. Furthermore, Toll-like receptor 4 (TLR4) mRNA expression was increased by β-glucan, and siRNA knockdown of TLR4 blocked β-glucan-induced MUC4 and MUC5B mRNA expression and β-glucan-activated phosphorylation of p38 MAPK and NF-κB. These results demonstrate that in human airway epithelial cells β-glucan induces MUC4 and MUC5B expression via the TLR4-p38 MAPK-NF-κB signaling pathway. © 2015 ARS-AAOA, LLC.

PP2A regulates SCF-induced cardiac stem cell migration through interaction with p38 MAPK.

PubMed

Wang, Ying; Xia, Yanli; Kuang, Dong; Duan, Yaqi; Wang, Guoping

2017-12-15

Previous studies have shown that stem cell factor (SCF) induces the migration of cardiac stem cells (CSCs) and helps to repair myocardial infarctions. Earlier studies on the migration mechanism only focused on the activation of kinases; here, we aimed to explore the functional role of protein phosphatase 2A (PP2A) in SCF-induced CSC migration. CSCs were treated with SCF, PP2A enzymatic activity was measured, the phosphorylation levels of PP2A, p38 MAPK and cofilin were evaluated using western blot. Transwell assay was used to determine the migratory ability of CSCs. In vitro, SCF induced the phosphorylation of p38 MAPK and cofilin, leading to the migration of CSCs. Cofilin acted as a downstream signal of p38 MAPK. PP2A was involved in this process. Further studies revealed that PP2A was inactivated via phosphorylation at Tyr307 by SCF and the inactivation/phosphorylation was mediated by activated p38 MAPK, as p38 MAPK inhibitor SB203580 or siRNA prevented SCF-induced inactivation and phosphorylation of PP2A. When CSCs were pretreated with PP2A inhibitor (okadaic acid, OA), SCF-induced CSC migration and the downstream signals were enhanced, and the enhancement was reversed when p38 MAPK was blocked. Additionally, co-immunoprecipitation showed a direct interaction of PP2A with p38 MAPK. Our results indicated that PP2A regulated the SCF-induced activation of p38 MAPK/cofilin signaling pathway and subsequent migration of CSCs by interaction with p38 MAPK. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

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. © 2015 The Authors The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.

Nur77 inhibits oxLDL induced apoptosis of macrophages via the p38 MAPK signaling pathway

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

Shao, Qin; Han, Fei; Peng, Shi

2016-03-18

The interaction between macrophages and oxLDL plays a crucial role in the initiation and progression of atherosclerosis. As a key initiator in a number of plaque promoting processes, oxLDL induces variable effects such as cell apoptosis or proliferation. Orphan nuclear receptor Nur77 is potently induced in macrophages by diverse stimuli, suggesting that it is of importance in vascular inflammation resulting in atherosclerosis, but whether Nur77 induction is detrimental or protective is unclear. In our study, we explore the role of Nur77 in the regulation of oxLDL-induced macrophage apoptosis and the signaling pathways that are involved. We found that oxLDL inducedmore » Nur77 expression in a dose and time dependent fashion, and cell viability was decreased in parallel. To determine whether Nur77 induction contributes to the loss of cell viability or is a protective mechanism, the effect of Nur77 overexpression was examined. Importantly, Nur77 overexpression inhibited the oxLDL-induced decrease of cell viability, inhibited the production of apoptotic bodies and restored DNA synthesis following oxLDL exposure. Furthermore, we found that Nur77 induction is mediated through the p38 MAPK signaling pathway. After pretreatment with SB203580, cell viability was decreased, the expression of CyclinA2 and PCNA was attenuated and the percentage of cell apoptosis was enhanced. Likewise, Nur77 overexpression increased the expression of the cell cycle genes PCNA and p21, and attenuated the increase in caspase-3. On the other hand, knockdown of Nur77 expression by specific siRNA resulted in the increased expression of caspase 3. The results demonstrate that Nur77 is induced by oxLDL via the p38 MAPK signaling pathway, which is involved in the regulation of cell survival. Nur77 enhanced cell survival via suppressing apoptosis, without affecting cell proliferation of activated macrophages, which may be beneficial in patients with atherosclerosis. - Highlights: • oxLDL could induce Nur77 expression. • Nur77 overexpression inhibited oxLDL-induced cell viability, production of apoptotic bodies and restored DNA synthesis. • Cell viability, CyclinA2 and PCNA expression and cell apoptosis were mediated through the p38 MAPK signaling pathway. • Nur77 overexpression mediated the expression of genes PCNA, p21, and caspase-3.« less

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

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

Mao, Jiamin

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

Roles of MAPK pathway activation during cytokine induction in BEAS-2B cells exposed to fine World Trade Center (WTC) dust.

PubMed

Wang, Shang; Prophete, Colette; Soukup, Joleen M; Chen, Lung-Chi; Costa, Max; Ghio, Andrew; Qu, Qingshan; Cohen, Mitchell D; Chen, Haobin

2010-01-01

The World Trade Center (WTC) collapse on September 11, 2001 released copious amounts of particulate matter (PM) into the atmosphere of New York City. Follow-up studies on persons exposed to the dusts have revealed a severely increased rate for asthma and other respiratory illnesses. There have only been a few studies that have sought to discern the possible mechanisms underlying these untoward pathologies. In one study, an increased cytokine release was detected in cells exposed to WTC fine dusts (PM₂.₅ fraction or WTC₂.₅). However, the mechanism(s) for these increases has yet to be fully defined. Because activation of the mitogen-activated protein kinase (MAPK) signaling pathways is known to cause cytokine induction, the current study was undertaken to analyze the possible involvement of these pathways in any increased cytokine formation by lung epithelial cells (as BEAS-2B cells) exposed to WTC₂.₅. Our results showed that exposure to WTC₂.₅ for 5 hr increased interleukin-6 (IL-6) mRNA expression in BEAS-2B cells, as well as its protein levels in the culture media, in a dose-dependent manner. Besides IL-6, cytokine multiplex analyses revealed that formation of IL-8 and -10 was also elevated by the exposure. Both extracellular signal-regulated kinase (ERK) and p38, but not c-Jun N-terminal protein kinase, signaling pathways were found to be activated in cells exposed to WTC₂.₅. Inactivation of ERK signaling pathways by PD98059 effectively blocked IL-6, -8, and -10 induction by WTC₂.₅; the p38 kinase inhibitor SB203580 significantly decreased induction of IL-8 and -10. Together, our data demonstrated activation of MAPK signaling pathway(s) likely played an important role in the WTC₂.₅-induced formation of several inflammatory (and, subsequently, anti-inflammatory) cytokines. The results are important in that they help to define one mechanism via which the WTC dusts may have acted to cause the documented increases in asthma and other inflammation-associated respiratory dysfunctions in the individuals exposed to the dusts released from the WTC collapse.

p38 MAP kinase is required for Wnt3a-mediated osterix expression independently of Wnt-LRP5/6-GSK3β signaling axis in dental follicle cells

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

Sakisaka, Yukihiko; Kanaya, Sousuke; Liason Center for Innovative Dentistry, Tohoku University Graduate School of Dentistry, Sendai 980-8575

Wnt3a is a secreted glycoprotein that activates the glycogen synthase kinase-3β (GSK3β)/β-catenin signaling pathway through low-density-lipoprotein receptor-related protein (LRP)5/6 co-receptors. Wnt3a has been implicated in periodontal development and homeostasis, as well as in cementum formation. Recently, we have reported that Wnt3a increases alkaline phosphatase expression through the induction of osterix (Osx) expression in dental follicle cells, a precursor of cementoblasts. However, the molecular mechanism by which Wnt3a induces Osx expression is still unknown. In this study, we show that Wnt3a-induced Osx expression was inhibited in the presence of p38 mitogen-activated protein kinase (MAPK) inhibitors (SB203580 and SB202190) at gene andmore » protein levels, as assessed by real-time PCR and immunocytohistochemistry, respectively. Pretreatment of cells with Dickkopf-1, a potent canonical Wnt antagonist binding to LRP5/6 co-receptors, did not influence Wnt3a-mediated p38 MAPK phosphorylation, suggesting that Wnt3a activates p38 MAPK through LRP5/6-independent signaling. On the other hand, pretreatment with p38 MAPK inhibitors had no effects on the phosphorylated status of GSK3β and β-catenin as well as β-catenin nuclear translocation, but inhibited Wnt3a-mediated β-catenin transcriptional activity. These findings suggest that p38 MAPK modulates canonical Wnt signaling at the β-catenin transcriptional level without any crosstalk with the Wnt3a-mediated LRP5/6-GSK3β signaling axis and subsequent β-catenin nuclear translocation. These findings expand our knowledge of the mechanisms controlling periodontal development and regeneration. - Highlights: • Wnt3a induces Osx expression via p38 MAPK signaling in dental follicle cells. • p38 MAPK has no crosstalk with Wnt3a-mediated LRP5/6 and GSK3β signaling. • p38 MAPK is required for Wnt signaling at the β-catenin transcriptional level.« less

CrMAPK3 regulates the expression of iron-deficiency-responsive genes in Chlamydomonas reinhardtii.

PubMed

Fei, Xiaowen; Yu, Junmei; Li, Yajun; Deng, Xiaodong

2017-05-16

Under iron-deficient conditions, Chlamydomonas exhibits high affinity for iron absorption. Nevertheless, the response, transmission, and regulation of downstream gene expression in algae cells have not to be investigated. Considering that the MAPK pathway is essential for abiotic stress responses, we determined whether this pathway is involved in iron deficiency signal transduction in Chlamydomonas. Arabidopsis MAPK gene sequences were used as entry data to search for homologous genes in Chlamydomonas reinhardtii genome database to investigate the functions of mitogen-activated protein kinase (MAPK) gene family in C. reinhardtii under iron-free conditions. Results revealed 16 C. reinhardtii MAPK genes labeled CrMAPK2-CrMAPK17 with TXY conserved domains and low homology to MAPK in yeast, Arabidopsis, and humans. The expression levels of these genes were then analyzed through qRT-PCR and exposure to high salt (150 mM NaCl), low nitrogen, or iron-free conditions. The expression levels of these genes were also subjected to adverse stress conditions. The mRNA levels of CrMAPK2, CrMAPK3, CrMAPK4, CrMAPK5, CrMAPK6, CrMAPK8, CrMAPK9, and CrMAPK11 were remarkably upregulated under iron-deficient stress. The increase in CrMAPK3 expression was 43-fold greater than that in the control. An RNA interference vector was constructed and transformed into C. reinhardtii 2A38, an algal strain with an exogenous FOX1:ARS chimeric gene, to silence CrMAPK3. After this gene was silenced, the mRNA levels and ARS activities of FOX1:ARS chimeric gene and endogenous CrFOX1 were decreased. The mRNA levels of iron-responsive genes, such as CrNRAMP2, CrATX1, CrFTR1, and CrFEA1, were also remarkably reduced. CrMAPK3 regulates the expression of iron-deficiency-responsive genes in C. reinhardtii.

The Regulation of Filamentous Growth in Yeast

PubMed Central

Cullen, Paul J.; Sprague, George F.

2012-01-01

Filamentous growth is a nutrient-regulated growth response that occurs in many fungal species. In pathogens, filamentous growth is critical for host–cell attachment, invasion into tissues, and virulence. The budding yeast Saccharomyces cerevisiae undergoes filamentous growth, which provides a genetically tractable system to study the molecular basis of the response. Filamentous growth is regulated by evolutionarily conserved signaling pathways. One of these pathways is a mitogen activated protein kinase (MAPK) pathway. A remarkable feature of the filamentous growth MAPK pathway is that it is composed of factors that also function in other pathways. An intriguing challenge therefore has been to understand how pathways that share components establish and maintain their identity. Other canonical signaling pathways—rat sarcoma/protein kinase A (RAS/PKA), sucrose nonfermentable (SNF), and target of rapamycin (TOR)—also regulate filamentous growth, which raises the question of how signals from multiple pathways become integrated into a coordinated response. Together, these pathways regulate cell differentiation to the filamentous type, which is characterized by changes in cell adhesion, cell polarity, and cell shape. How these changes are accomplished is also discussed. High-throughput genomics approaches have recently uncovered new connections to filamentous growth regulation. These connections suggest that filamentous growth is a more complex and globally regulated behavior than is currently appreciated, which may help to pave the way for future investigations into this eukaryotic cell differentiation behavior. PMID:22219507

Conservation of Chitin-Induced MAPK Signaling Pathways in Rice and Arabidopsis.

PubMed

Yamada, Kenta; Yamaguchi, Koji; Yoshimura, Satomi; Terauchi, Akira; Kawasaki, Tsutomu

2017-06-01

Perception of microbe-associated molecular patterns (MAMPs) including chitin by pattern recognition receptors (PRRs) rapidly induces activation of mitogen-activated protein kinase (MAPK) cascades. However, how PRRs transmit immune signals to the MAPK cascade is largely unknown. Recently, Arabidopsis receptor-like cytoplasmic kinase PBL27 has been reported to activate MAPKs through phosphorylation of AtMAPKKK5 in the chitin signaling pathway. In this study, we found that OsRLCK185, a rice ortholog of PBL27, regulates chitin-induced MAPK activation in a similar fashion to PBL27 in rice. Upon chitin perception, OsRLCK185 is phosphorylated by OsCERK1, a component of the chitin receptor complex. OsRLCK185 interacted with OsMAPKKK11 and OsMAPKKK18, rice orthologs of AtMAPKKK5, in yeast two-hybrid assays. Silencing of both OsMAPKKK11 and OsMAPKKK18 significantly reduced chitin-induced activation of OsMPK3 and OsMPK6. Expression levels of OsMAPKKK18 were much higher than that of OsMAPKKK11 in rice cells, which was consistent with the fact that the Osmapkkk11 single mutation did not affect MAPK activation. This result suggested that OsMAPKKK18 plays a more important role than OsMAPKKK11 in the chitin-induced activation of OsMPK3 and OsMPK6. The bimolecular fluorescence complementation (BiFC) experiment indicated that OsRLCK185 interacted with OsMAPKKK18 at the plasma membrane in planta. In vitro phosphorylation experiments showed that OsRLCK185 directly phosphorylates OsMAPKKK18. Furthermore, OsMAPKKK18 interacted with the MAPKK OsMKK4, the upstream component of OsMPK3/6. These results suggested that OsRLCK185 connects the chitin receptor to the MAPK cascade consisting of OsMAPKKK18-OsMKK4-OsMPK3/6. Our data revealed that chitin-induced MAPK activation in rice and Arabidopsis is regulated by common homologous elements. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

MiR-592 Promotes Gastric Cancer Proliferation, Migration, and Invasion Through the PI3K/AKT and MAPK/ERK Signaling Pathways by Targeting Spry2.

PubMed

He, Yu; Ge, Yugang; Jiang, Mingkun; Zhou, Jundong; Luo, Dakui; Fan, Hao; Shi, Liang; Lin, Linling; Yang, Li

2018-06-21

Gastric cancer (GC) is one of the most prevalent digestive malignancies. MicroRNAs (miRNAs) are involved in multiple cellular processes, including oncogenesis, and miR-592 itself participates in many malignancies; however, its role in GC remains unknown. In this study, we investigated the expression and molecular mechanisms of miR-592 in GC. Quantitative real-time PCR and immunohistochemistry were performed to determine the expression of miR-592 and its putative targets in human tissues and cell lines. Proliferation, migration, and invasion were evaluated by Cell Counting Kit-8, population doubling time, colony formation, Transwell, and wound-healing assays in transfected GC cells in vitro. A dual-luciferase reporter assay was used to determine whether miR-592 could directly bind its target. A tumorigenesis assay was used to study whether miR-592 affected GC growth in vivo. Proteins involved in signaling pathways and the epithelial-mesenchymal transition (EMT) were detected with western blot. The ectopic expression of miR-592 promoted GC proliferation, migration, and invasion in vitro and facilitated tumorigenesis in vivo. Spry2 was a direct target of miR-592 and Spry2 overexpression partially counteracted the effects of miR-592. miR-592 induced the EMT and promoted its progression in GC via the PI3K/AKT and MAPK/ERK signaling pathways by inhibiting Spry2. Overexpression of miR-592 promotes GC proliferation, migration, and invasion and induces the EMT via the PI3K/AKT and MAPK/ERK signaling pathways by inhibiting Spry2, suggesting a potential therapeutic target for GC. © 2018 The Author(s). Published by S. Karger AG, Basel.

The p38 mitogen activated protein kinase regulates β-amyloid protein internalization through the α7 nicotinic acetylcholine receptor in mouse brain.

PubMed

Ma, Kai-Ge; Lv, Jia; Yang, Wei-Na; Chang, Ke-Wei; Hu, Xiao-Dan; Shi, Li-Li; Zhai, Wan-Ying; Zong, Hang-Fan; Qian, Yi-Hua

2018-03-01

Alzheimer's disease (AD) is one of the most devastating neurodegenerative disorders. Intracellular β-amyloid protein (Aβ) is an early event in AD. It induces the formation of amyloid plaques and neuron damage. The α7 nicotinic acetylcholine receptor (α7nAChR) has been suggested to play an important role in Aβ caused cognition. It has high affinity with Aβ and could mediate Aβ internalization in vitro. However, whether in mouse brain the p38 MAPK signaling pathway is involved in the regulation of the α7nAChR mediated Aβ internalization and their role in mitochondria remains little known. Therefore, in this study, we revealed that Aβ is internalized by cholinergic and GABAergic neurons. The internalized Aβ were found deposits in lysosomes/endosomes and mitochondria. Aβ could form Aβ-α7nAChR complex with α7nAChR, activates the p38 mitogen activated protein kinase (MAPK). And the increasing of α7nAChR could in return mediate Aβ internalization in the cortex and hippocampus. In addition, by using the α7nAChR agonist PNU282987, the p38 phosphorylation level decreases, rescues the biochemical changes which are tightly associated with Aβ-induced apoptosis, such as Bcl2/Bax level, cytochrome c (Cyt c) release. Collectively, the p38 MAPK signaling pathway could regulate the α7nAChR-mediated internalization of Aβ. The activation of α7nAChR or the inhibition of p38 MAPK signaling pathway may be a beneficial therapy to AD. Copyright © 2017 Elsevier Inc. All rights reserved.

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

PubMed

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

2018-01-31

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

Amino-modified polystyrene nanoparticles affect signalling pathways of the sea urchin (Paracentrotus lividus) embryos.

PubMed

Pinsino, Annalisa; Bergami, Elisa; Della Torre, Camilla; Vannuccini, Maria Luisa; Addis, Piero; Secci, Marco; Dawson, Kenneth A; Matranga, Valeria; Corsi, Ilaria

2017-03-01

Polystyrene nanoparticles have been shown to pose serious risk to marine organisms including sea urchin embryos based on their surface properties and consequently behaviour in natural sea water. The aim of this study is to investigate the toxicity pathways of amino polystyrene nanoparticles (PS-NH 2 , 50 nm) in Paracentrotus lividus embryos in terms of development and signalling at both protein and gene levels. Two sub-lethal concentrations of 3 and 4 μg/mL of PS-NH 2 were used to expose sea urchin embryos in natural sea water (PS-NH 2 as aggregates of 143 ± 5 nm). At 24 and 48 h post-fertilisation (hpf) embryonic development was monitored and variations in the levels of key proteins involved in stress response and development (Hsp70, Hsp60, MnSOD, Phospho-p38 Mapk) as well as the modulation of target genes (Pl-Hsp70, Pl-Hsp60, Pl-Cytochrome b, Pl-p38 Mapk, Pl-Caspase 8, Pl-Univin) were measured. At 48 hpf various striking teratogenic effects were observed such as the occurrence of cells/masses randomly distributed, severe skeletal defects and delayed development. At 24 hpf a significant up-regulation of Pl-Hsp70, Pl-p38 Mapk, Pl-Univin and Pl-Cas8 genes was found, while at 48 hpf only for Pl-Univin was observed. Protein profile showed different patterns as a significant increase of Hsp70 and Hsp60 only after 48 hpf compared to controls. Conversely, P-p38 Mapk protein significantly increased at 24 hpf and decreased at 48 hpf. Our findings highlight that PS-NH 2 are able to disrupt sea urchin embryos development by modulating protein and gene profile providing new understandings into the signalling pathways involved.

Neuroprotective effects of ebselen in traumatic brain injury model: involvement of nitric oxide and p38 mitogen-activated protein kinase signalling pathway.

PubMed

Wei, Liang; Zhang, Yanfei; Yang, Cheng; Wang, Qi; Zhuang, Zhongwei; Sun, Zhiyang

2014-02-01

Previous investigations have found that ebselen is able to treat neurodegenerative diseases caused by radical and acute total cerebral ischaemia. The aim of the present study was to investigate the neuroprotective effects of ebselen in a traumatic brain injury (TBI) model. Ninety Sprague-Dawley rats were randomly divided into five groups (n = 18 in each): (i) sham operation; (ii) an injury model group; (iii) low-dose (3 mg/kg) ebselen-treated group; (iv) a moderate-dose (10 mg/kg) ebselen-treated group; and (v) a high-dose (30 mg/kg) ebselen-treated group. The TBI model was created according using a modified weight-drop model. Neurological severity score (NSS), brain water content and histopathological deficits were assessed as parameters of injury severity. Expression of nitric oxide (NO), inducible NO synthase (iNOS) mRNA, Toll-like receptor (TLR) and phosphorylated (p-) p38 mitogen-activated protein kinase (MAPK) were examined by chemical colorimetry, quantitative polymerase chain reaction and western blotting 24 h after intragastric ebselen administration. Rats in the TBI model group exhibited markedly more severe neurological injury (higher NSS, more brain water content and more histopathological deficits) than those in the sham-operated group. Ebselen treatment significantly ameliorated the neurological injury of TBI rats in a dose-dependent manner. Moreover, ebselen significantly reduced the NO and iNOS mRNA levels and inhibited TLR4 and p-p38 MAPK expression, indicating the involvement of NO and p38 MAPK signalling pathways in the neuroprotection afforded by ebselen. In conclusion, ebselen ameliorated neurological injury, possibly by reducing NO levels and modulating the TLR4-mediated p38 MAPK signalling pathway. Therefore, ebselen may have potential to treat secondary injuries of TBI. © 2013 Wiley Publishing Asia Pty Ltd.

Phosphorylated 4EBP1 is associated with tumor progression and poor prognosis in Xp11.2 translocation renal cell carcinoma

PubMed Central

Qu, Yuanyuan; Zhao, Rui; Wang, Hongkai; Chang, Kun; Yang, Xiaoqun; Zhou, Xiaoyan; Dai, Bo; Zhu, Yao; Shi, Guohai; Zhang, Hailiang; Ye, Dingwei

2016-01-01

Two main signaling pathways, PI3K-AKT-mTOR and RAS-MAPK, are involved in transmitting the proliferative signals which play critical roles in human cancers. However, the functions of these pathways in Xp11.2 RCC remain undefined. This study aimed to explore the expression of mTOR and MAPK cascades in Xp11.2 RCC and to assess the prognostic significance of proteins evaluated. Immunohistochemistry was performed to evaluate the expression of 4EBP1, p-4EBP1, p-mTOR, p-S6K and p-MAPK in 36 adult Xp11.2 RCC patients who were confirmed by FISH assay. Cox regression models were used to evaluate the prognostic value of all covariates. Among 36 assessed patients, 14 (38.9%), 26 (72.2%), 16 (44.4%), 19 (52.8%), and 9 (25.0%) patients showed high expression of 4EBP1, p-4EBP1, p-mTOR, p-S6K, and p-MAPK, respectively. We noted that p-4EBP1 expression was significantly correlated with lymph node metastases (P = 0.027). Multivariate analysis showed that high p-4EBP1 expression was an independent adverse prognostic factor for both PFS (HR = 33.750, P = 0.017) and OS (HR = 56.111, P = 0.026). Our findings suggest that p-4EBP1 may serve as a funnel factor that converge the upstream proliferative oncogenic signals. Effective inhibition of the pathways responsible for 4E-BP1 phosphorylation might be a useful strategy to improve the outcome of Xp11.2 RCC patients. PMID:27026382

Phosphorylated 4EBP1 is associated with tumor progression and poor prognosis in Xp11.2 translocation renal cell carcinoma.

PubMed

Qu, Yuanyuan; Zhao, Rui; Wang, Hongkai; Chang, Kun; Yang, Xiaoqun; Zhou, Xiaoyan; Dai, Bo; Zhu, Yao; Shi, Guohai; Zhang, Hailiang; Ye, Dingwei

2016-03-30

Two main signaling pathways, PI3K-AKT-mTOR and RAS-MAPK, are involved in transmitting the proliferative signals which play critical roles in human cancers. However, the functions of these pathways in Xp11.2 RCC remain undefined. This study aimed to explore the expression of mTOR and MAPK cascades in Xp11.2 RCC and to assess the prognostic significance of proteins evaluated. Immunohistochemistry was performed to evaluate the expression of 4EBP1, p-4EBP1, p-mTOR, p-S6K and p-MAPK in 36 adult Xp11.2 RCC patients who were confirmed by FISH assay. Cox regression models were used to evaluate the prognostic value of all covariates. Among 36 assessed patients, 14 (38.9%), 26 (72.2%), 16 (44.4%), 19 (52.8%), and 9 (25.0%) patients showed high expression of 4EBP1, p-4EBP1, p-mTOR, p-S6K, and p-MAPK, respectively. We noted that p-4EBP1 expression was significantly correlated with lymph node metastases (P = 0.027). Multivariate analysis showed that high p-4EBP1 expression was an independent adverse prognostic factor for both PFS (HR = 33.750, P = 0.017) and OS (HR = 56.111, P = 0.026). Our findings suggest that p-4EBP1 may serve as a funnel factor that converge the upstream proliferative oncogenic signals. Effective inhibition of the pathways responsible for 4E-BP1 phosphorylation might be a useful strategy to improve the outcome of Xp11.2 RCC patients.

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

PubMed

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

2017-03-29

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

SK-N-MC cell death occurs by distinct molecular mechanisms in response to hydrogen peroxide and superoxide anions: involvements of JAK2-STAT3, JNK, and p38 MAP kinases pathways.

PubMed

Moslehi, Maryam; Yazdanparast, Razieh

2013-07-01

Oxidative stress plays a vital role in the pathogenesis of neurodegenerative diseases. Nerve cells are incessantly exposed to environmental stresses leading to overproduction of some harmful species like reactive oxygen species (ROS). ROS including hydrogen peroxide and superoxide anion are potent inducers of various signaling pathways encompassing MAPKs and JAK-STAT pathways. In the current study, we scrutinized the effects of hydrogen peroxide and/or menadione (superoxide anion generator) on JNK/p38-MAPKs and JAK2-STAT3 pathways to elucidate the mechanism(s) by which each oxidant modulated the above-mentioned pathways leading to SK-N-MC cell death. Our results delineated that hydrogen peroxide and superoxide anion radical induced distinct responses as we showed that STAT3 and p38 were activated in response to hydrogen peroxide, but not superoxide anion radicals indicating the specificity in ROS-induced signaling pathways activations and behaviors. We also observed that menadione induced JNK-dependent p53 expression and apoptotic death in SK-N-MC cells while H2O2-induced JNK activation was p53 independent. Thus, we declare that ROS type has a key role in selective instigation of JNK/p38-MAPKs and JAK2-STAT3 pathways in SK-N-MC cells. Identifying these differential behaviors and mechanisms of hydrogen peroxide and superoxide anion functions illuminates the possible therapeutic targets in the prevention or treatment of ROS-induced neurodegenerative diseases such as Alzheimer's disease.

Long non-coding RNA-mediated regulation of signaling pathways in gastric cancer.

PubMed

Zong, Wei; Ju, Shaoqing; Jing, Rongrong; Cui, Ming

2018-05-28

Gastric cancer (GC) is one of the most common cancers globally. Because of the high frequency of tumor recurrence, or metastasis, after surgical resection, the prognosis of patients with GC is poor. Therefore, exploring the mechanisms underlying GC is of great importance. Recently, accumulating evidence has begun to show that dysregulated long non-coding RNAs (lncRNAs) participate in the progression of GC via several typical signaling pathways, such as the AKT and MAPK signaling pathways. Moreover, the interactions between lncRNAs and microRNAs appear to represent a novel mechanism in the pathogenesis of GC. This review provides a synopsis of the latest research relating to lncRNAs and associated signaling pathways in GC.

Signalling and chemosensitivity assays in melanoma: is mutated status a prerequisite for targeted therapy?

PubMed

Passeron, Thierry; Lacour, Jean-Philippe; Allegra, Maryline; Ségalen, Coralie; Deville, Anne; Thyss, Antoine; Giacchero, Damien; Ortonne, Jean-Paul; Bertolotto, Corine; Ballotti, Robert; Bahadoran, Philippe

2011-12-01

Selection for targeted therapies in melanoma is currently based on the search for mutations in selected genes. We aimed at evaluating the interest of signalling and chemosensitivity studies in addition to genotyping for assessing the best suitable treatment in an individual patient. We extracted genomic DNA and melanoma cells from tumor tissue of a skin metastasis of a 17-year-old woman with stage IV melanoma progressing despite three successive lines of treatment. Despite the absence of mutation in BRAF, NRAS cKIT, the MAPK pathway was activated and a significant response to sorafenib, a mitogen-activated protein kinase (MAPK)/RAF inhibitor, was found in signalling and chemosensitivity assays. A treatment combining sorafenib and dacarbazine produced a partial response for 9 months, with marked necrosis in some lesions. Chemosensitivity assays and signalling pathway studies could be of great value in addition to genotyping for assessing the most appropriate treatment in melanoma. © 2011 John Wiley & Sons A/S.

TAK-242, a small-molecule inhibitor of Toll-like receptor 4 signalling, unveils similarities and differences in lipopolysaccharide- and lipidinduced inflammation and insulin resistance in muscle cells

PubMed Central

Hussey, Sophie E.; Liang, Hanyu; Costford, Sheila R.; Klip, Amira; DeFronzo, Ralph A.; Sanchez-Avila, Alicia; Ely, Brian; Musi, Nicolas

2012-01-01

Emerging evidence suggests that TLR (Toll-like receptor) 4 and downstream pathways [MAPKs (mitogen-activated protein kinases) and NF-κB (nuclear factor κB)] play an important role in the pathogenesis of insulin resistance. LPS (lipopolysaccharide) and saturated NEFA (non-esterified fatty acids) activate TLR4, and plasma concentrations of these TLR4 ligands are elevated in obesity and Type 2 diabetes. Our goals were to define the role of TLR4 on the insulin resistance caused by LPS and saturated NEFA, and to dissect the independent contribution of LPS and NEFA to the activation of TLR4-driven pathways by employing TAK-242, a specific inhibitor of TLR4. LPS caused robust activation of the MAPK and NF-κB pathways in L6 myotubes, along with impaired insulin signalling and glucose transport. TAK-242 completely prevented the inflammatory response (MAPK and NF-κB activation) caused by LPS, and, in turn, improved LPS-induced insulin resistance. Similar to LPS, stearate strongly activated MAPKs, although stimulation of the NF-κB axis was modest. As seen with LPS, the inflammatory response caused by stearate was accompanied by impaired insulin action. TAK-242 also blunted stearate-induced inflammation; yet, the protective effect conferred by TAK-242 was partial and observed only on MAPKs. Consequently, the insulin resistance caused by stearate was only partially improved by TAK-242. In summary, TAK-242 provides complete and partial protection against LPS- and NEFA-induced inflammation and insulin resistance, respectively. Thus, LPS-induced insulin resistance depends entirely on TLR4, whereas NEFA works through TLR4-dependent and -independent mechanisms to impair insulin action. PMID:23050932

TAK-242, a small-molecule inhibitor of Toll-like receptor 4 signalling, unveils similarities and differences in lipopolysaccharide- and lipid-induced inflammation and insulin resistance in muscle cells.

PubMed

Hussey, Sophie E; Liang, Hanyu; Costford, Sheila R; Klip, Amira; DeFronzo, Ralph A; Sanchez-Avila, Alicia; Ely, Brian; Musi, Nicolas

2012-11-30

Emerging evidence suggests that TLR (Toll-like receptor) 4 and downstream pathways [MAPKs (mitogen-activated protein kinases) and NF-κB (nuclear factor κB)] play an important role in the pathogenesis of insulin resistance. LPS (lipopolysaccharide) and saturated NEFA (non-esterified fatty acids) activate TLR4, and plasma concentrations of these TLR4 ligands are elevated in obesity and Type 2 diabetes. Our goals were to define the role of TLR4 on the insulin resistance caused by LPS and saturated NEFA, and to dissect the independent contribution of LPS and NEFA to the activation of TLR4-driven pathways by employing TAK-242, a specific inhibitor of TLR4. LPS caused robust activation of the MAPK and NF-κB pathways in L6 myotubes, along with impaired insulin signalling and glucose transport. TAK-242 completely prevented the inflammatory response (MAPK and NF-κB activation) caused by LPS, and, in turn, improved LPS-induced insulin resistance. Similar to LPS, stearate strongly activated MAPKs, although stimulation of the NF-κB axis was modest. As seen with LPS, the inflammatory response caused by stearate was accompanied by impaired insulin action. TAK-242 also blunted stearate-induced inflammation; yet, the protective effect conferred by TAK-242 was partial and observed only on MAPKs. Consequently, the insulin resistance caused by stearate was only partially improved by TAK-242. In summary, TAK-242 provides complete and partial protection against LPS- and NEFA-induced inflammation and insulin resistance, respectively. Thus, LPS-induced insulin resistance depends entirely on TLR4, whereas NEFA works through TLR4-dependent and -independent mechanisms to impair insulin action.

Spirulina platensis prevents hyperglycemia in rats by modulating gluconeogenesis and apoptosis via modification of oxidative stress and MAPK-pathways.

PubMed

Sadek, Kadry M; Lebda, Mohamed A; Nasr, Sherif M; Shoukry, Moustafa

2017-08-01

Spirulina platensis (SP) is a microalga with antioxidant, antidiabetic and anti-inflammatory properties. The present study explored the ability and potential mechanism(s) by which SP induced glucose lowering impact in diabetic rat model. Forty rats were allocated into four groups: control; streptozotocin (STZ)-induced diabetes (STZ, 45mg/kg b.w., intraperitoneally); SP (500mg/kg b.w., orally twice weekly for 2 months) and STZ-induced diabetes+SP group. In the STZ-induced diabetic rats, SP significantly decreased (P>0.05) serum glucose, glycated hemoglobin (HbA1c), malondialdehyde (MDA) levels and significantly increased (P>0.05) serum insulin, the activity of antioxidant enzymes and normalized their mRNA gene expression. Furthermore, SP attenuates STZ-induced upregulation of the gluconeogenic enzyme pyruvate carboxylase (PC), the pro-apoptotic Bax and caspase-3 (CASP-3), tumor necrosis factor alpha (TNF-α) gene expression. The Western blot results revealed that, SP induced downregulation of mitogen activated protein kinase pathway (MAPK) protein expression in hepatic tissues of diabetic rats. Additionally, SP reestablished the typical histological structure of the liver and pancreas of diabetic rats. Acute toxicity study further shows that SP is relatively safe. This study demonstrates that SP is rich in antioxidant compounds and has powerful glucose lowering effect through the normalization of increased hepatic PC gene expression. Interestingly, SP induced recovery of damaged hepatocytes and pancreatic β-cells via its anti-inflammatory, antioxidant and anti-apoptotic properties. The MAPK signaling cascade is a pivotal component of the proapoptotic signaling pathway induced by diabetes mellitus. MAPK activation may be dependent from ROS production, since SP which exhibited antioxidant activities did have a significant impact on MAPK activity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

TMPYP4 exerted antitumor effects in human cervical cancer cells through activation of p38 mitogen-activated protein kinase.

PubMed

Cheng, Ming-Jun; Cao, Yun-Gui

2017-07-03

The aim of the present study was to investigate the potential effects of the 5,10,15,20-tetrakis (1-methylpyridinium-4-yl) porphyrin (TMPyP4) on the proliferation and apoptosis of human cervical cancer cells and the underlying mechanisms by which TMPyP4 exerted its actions. After human cervical cancer cells were treated with different doses of TMPyP4, cell viability was determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) method, the apoptosis was observed by flow cytometry (FCM), and the expression of p38 mitogen-activated protein kinase (MAPK), phosphated p38 MAPK (p-p38 MAPK), capase-3, MAPKAPK2 (MK-2) and poly ADP-ribose polymerase (PARP) was measured by Western blot analysis. The analysis revealed that TMPyP4 potently suppressed cell viability and induced the apoptosis of human cervical cancer cells in a dose-dependent manner. In addition, the up-regulation of p-p38 MAPK expression levels was detected in TMPyP4-treated human cervical cancer cells. However, followed by the block of p38 MAPK signaling pathway using the inhibitor SB203580, the effects of TMPyP4 on proliferation and apoptosis of human cervical cancer cells were significantly changed. It was indicated that TMPyP4-inhibited proliferation and -induced apoptosis in human cervical cancer cells was accompanied by activating the p38 MAPK signaling pathway. Taken together, our study demonstrates that TMPyP4 may represent a potential therapeutic method for the treatment of cervical carcinoma.

Chronic intermittent hypoxia induces liver fibrosis in mice with diet-induced obesity via TLR4/MyD88/MAPK/NF-kB signaling pathways.

PubMed

Kang, Hyeon Hui; Kim, In Kyoung; Lee, Hye In; Joo, Hyonsoo; Lim, Jeong Uk; Lee, Jongmin; Lee, Sang Haak; Moon, Hwa Sik

2017-08-19

Obstructive sleep apnea (OSA) is associated with nonalcoholic fatty liver disease (NAFLD), and causes chronic intermittent hypoxia (CIH) during sleep. Inflammation is associated with the development of metabolic complications induced by CIH. Research suggests that innate immune mechanisms are involved in the pro-inflammatory pathways of liver fibrosis. The purpose of this study was to investigate whether innate immune responses induce liver fibrosis, and to evaluate mechanisms underlying hepatic inflammation related to CIH in a murine diet-induced obesity (DIO) model. Inflammatory and oxidative stress markers, TLR4, MyD88, Toll/interleukin-1-receptor-domain-containing adaptor-inducing interferon-β (TRIF), I-κB, NF-κB, p38 MAPK, c-JNK, and ERK activation, were measured in the serum and liver. As a result, α1(I)-collagen mRNA was significantly higher in DIO mice exposed to CIH than in the control groups. CIH mice exhibited liver fibrosis and significantly higher protein expression of TLR4, MyD88, phosphorylated (phospho-) I-κB, and phospho-ERK1/2 activation in the liver, and higher expression of NF-κB than that in the controls. TRIF, p38 MAPK, and JNK activation did not differ significantly between groups. We conclude that CIH in DIO mice leads to liver fibrosis via TLR4/MyD88/MAPK/NF-kB signaling pathways. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Nox4 NADPH oxidase-derived reactive oxygen species, via endogenous carbon monoxide, promote survival of brain endothelial cells during TNF-α-induced apoptosis

PubMed Central

Basuroy, Shyamali; Tcheranova, Dilyara; Bhattacharya, Sujoy; Leffler, Charles W.

2011-01-01

We investigated the role of reactive oxygen species (ROS) in promoting cell survival during oxidative stress induced by the inflammatory mediator tumor necrosis factor-α (TNF-α) in cerebral microvascular endothelial cells (CMVEC) from newborn piglets. Nox4 is the major isoform of NADPH oxidase responsible for TNF-α-induced oxidative stress and apoptosis in CMVEC. We present novel data that Nox4 NADPH oxidase-derived ROS also initiate a cell survival mechanism by increasing production of a gaseous antioxidant mediator carbon monoxide (CO) by constitutive heme oxygenase-2 (HO-2). TNF-α rapidly enhanced endogenous CO production in a superoxide- and NADPH oxidase-dependent manner in CMVEC with innate, but not with small interfering RNA (siRNA)-downregulated Nox4 activity. CORM-A1, a CO-releasing compound, inhibited Nox4-mediated ROS production and enhanced cell survival in TNF-α-challenged CMVEC. The ROS-induced CO-mediated survival mechanism requires functional interactions between the protein kinase B/Akt and extracellular signal-related kinase (ERK)/p38 MAPK signaling pathways activated by TNF-α. In Akt siRNA-transfected CMVEC and in cells with pharmacologically inhibited Akt, Erk1/2, and p38 mitogen-activated protein kinase (MAPK) activities, CORM-A1 was no longer capable of blocking Nox4 activation and apoptosis caused by TNF-α. Overall, Nox4 NADPH oxidase-derived ROS initiate both death and survival pathways in TNF-α-challenged CMVEC. The ROS-dependent cell survival pathway is mediated by an endogenous antioxidant CO, which inhibits Nox4 activation via a mechanism that includes Akt, ERK1/2, and p38 MAPK signaling pathways. The ability of CO to inhibit TNF-α-induced ERK1/2 and p38 MAPK activities in an Akt-dependent manner appears to be the key element in ROS-dependent survival of endothelial cells during TNF-α-mediated brain inflammatory disease. PMID:21123734

PP2B and ERK1/2 regulate hyaluronan synthesis of HT168 and WM35 human melanoma cell lines.

PubMed

Katona, Éva; Juhász, Tamás; Somogyi, Csilla Szűcs; Hajdú, Tibor; Szász, Csaba; Rácz, Kálmán; Kókai, Endre; Gergely, Pál; Zákány, Róza

2016-03-01

Hyaluronan (HA) is the major glycosaminoglycan component of the extracellular matrix in either normal or malignant tissues and it may affect proliferation, motility and differentiation of various cell types. Three isoforms of plasma membrane-bound hyaluronan synthases (HAS 1, 2 and 3) secrete and simultaneously bind pericellular HA. HAS enzymes are subjects of post-translational protein phosphorylation which is believed to regulate their enzymatic activity. In this study, we investigated the HA homeostasis of normal human epidermal melanocytes, HT168 and WM35 human melanoma cell lines and melanoma metastases. HAS2 and HAS3 were detected in all the samples, while the expression of HAS1 was not detectable in any case. Malignant tissue samples and melanoma cell lines contained extra- and intracellular HA abundantly but not normal melanocytes. Applying HA as a chemoattractant facilitated the migration of melanoma cells in Boyden chamber. The amount of HA was reduced upon the inhibition of calcineurin with cyclosporine A (CsA), while the inhibition of ERK1/2 with PD098059 elevated it in both cell lines. The signals of Ser/Thr phosphoproteins at 57 kD were stronger after CsA treatment, while a markedly weaker signal was detected upon inhibition of the MAPK pathway. Our results suggest opposing effects of the two investigated enzymes on the HA homeostasis of melanoma cells. We propose that the dephosphorylation of HAS enzymes targeted by PP2B augments HA production, while their phosphorylation by the activity of MAPK pathway reduces HA synthesis. As the expression of the HA receptor RHAMM was also significantly enhanced by PD098059, the MAPK pathway exerted a complex attenuating effect on HA signalling in the investigated melanoma cells. This observation suggests that the application of MAPK-ERK pathway inhibitors requires a careful therapeutic design in melanoma treatment.

PP2B and ERK1/2 regulate hyaluronan synthesis of HT168 and WM35 human melanoma cell lines

PubMed Central

KATONA, ÉVA; JUHÁSZ, TAMÁS; SOMOGYI, CSILLA SZŰCS; HAJDÚ, TIBOR; SZÁSZ, CSABA; RÁCZ, KÁLMÁN; KÓKAI, ENDRE; GERGELY, PÁL; ZÁKÁNY, RÓZA

2016-01-01

Hyaluronan (HA) is the major glycosaminoglycan component of the extracellular matrix in either normal or malignant tissues and it may affect proliferation, motility and differentiation of various cell types. Three isoforms of plasma membrane-bound hyaluronan synthases (HAS 1, 2 and 3) secrete and simultaneously bind pericellular HA. HAS enzymes are subjects of post-translational protein phosphorylation which is believed to regulate their enzymatic activity. In this study, we investigated the HA homeostasis of normal human epidermal melanocytes, HT168 and WM35 human melanoma cell lines and melanoma metastases. HAS2 and HAS3 were detected in all the samples, while the expression of HAS1 was not detectable in any case. Malignant tissue samples and melanoma cell lines contained extra- and intracellular HA abundantly but not normal melanocytes. Applying HA as a chemoattractant facilitated the migration of melanoma cells in Boyden chamber. The amount of HA was reduced upon the inhibition of calcineurin with cyclosporine A (CsA), while the inhibition of ERK1/2 with PD098059 elevated it in both cell lines. The signals of Ser/Thr phosphoproteins at 57 kD were stronger after CsA treatment, while a markedly weaker signal was detected upon inhibition of the MAPK pathway. Our results suggest opposing effects of the two investigated enzymes on the HA homeostasis of melanoma cells. We propose that the dephosphorylation of HAS enzymes targeted by PP2B augments HA production, while their phosphorylation by the activity of MAPK pathway reduces HA synthesis. As the expression of the HA receptor RHAMM was also significantly enhanced by PD098059, the MAPK pathway exerted a complex attenuating effect on HA signalling in the investigated melanoma cells. This observation suggests that the application of MAPK-ERK pathway inhibitors requires a careful therapeutic design in melanoma treatment. PMID:26717964

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.

MAPK signaling is required for LPS-induced VEGF in pulp stem cells.

PubMed

Botero, T M; Son, J S; Vodopyanov, D; Hasegawa, M; Shelburne, C E; Nör, J E

2010-03-01

Caries-induced pulpitis is typically accompanied by an increase in dental pulp microvascular density. However, the mechanisms by which dental pulp cells recognize lipopolysaccharides (LPSs) remain unclear. We hypothesized that Porphyromonas endodontalis and Escherichia coli LPSs induce vascular endothelial growth factor (VEGF) expression in dental pulp stem cells (DPSC) and human dental pulp fibroblasts (HDPF) through mitogen-activated protein kinase (MAPK) signaling. ELISA, semi-quantitative RT-PCR, immunofluorescence, and Western blots were used. Here, we observed that LPSs induced VEGF expression in DPSC and HDPF cells, and both cell types express Toll-like receptor 4 (TLR- 4). Notably, LPS-induced VEGF is associated with phosphorylation of protein kinase C (PKC zeta) and extracellular signal-regulator kinase (ERK1/2) and is dependent upon MAPK activation. Analysis of these data, collectively, unveils a signaling pathway responsible for synthesis of VEGF by pulp cells and suggests a novel therapeutic target for the management of vascular responses in teeth with pulpitis.

Cellular reprogramming through mitogen-activated protein kinases.

PubMed

Lee, Justin; Eschen-Lippold, Lennart; Lassowskat, Ines; Böttcher, Christoph; Scheel, Dierk

2015-01-01

Mitogen-activated protein kinase (MAPK) cascades are conserved eukaryote signaling modules where MAPKs, as the final kinases in the cascade, phosphorylate protein substrates to regulate cellular processes. While some progress in the identification of MAPK substrates has been made in plants, the knowledge on the spectrum of substrates and their mechanistic action is still fragmentary. In this focused review, we discuss the biological implications of the data in our original paper (Sustained mitogen-activated protein kinase activation reprograms defense metabolism and phosphoprotein profile in Arabidopsis thaliana; Frontiers in Plant Science 5: 554) in the context of related research. In our work, we mimicked in vivo activation of two stress-activated MAPKs, MPK3 and MPK6, through transgenic manipulation of Arabidopsis thaliana and used phosphoproteomics analysis to identify potential novel MAPK substrates. Here, we plotted the identified putative MAPK substrates (and downstream phosphoproteins) as a global protein clustering network. Based on a highly stringent selection confidence level, the core networks highlighted a MAPK-induced cellular reprogramming at multiple levels of gene and protein expression-including transcriptional, post-transcriptional, translational, post-translational (such as protein modification, folding, and degradation) steps, and also protein re-compartmentalization. Additionally, the increase in putative substrates/phosphoproteins of energy metabolism and various secondary metabolite biosynthesis pathways coincides with the observed accumulation of defense antimicrobial substances as detected by metabolome analysis. Furthermore, detection of protein networks in phospholipid or redox elements suggests activation of downstream signaling events. Taken in context with other studies, MAPKs are key regulators that reprogram cellular events to orchestrate defense signaling in eukaryotes.

Protocatechuic Acid from Alpinia oxyphylla Induces Schwann Cell Migration via ERK1/2, JNK and p38 Activation.

PubMed

Ju, Da-Tong; Kuo, Wei-Wen; Ho, Tsung-Jung; Paul, Catherine Reena; Kuo, Chia-Hua; Viswanadha, Vijaya Padma; Lin, Chien-Chung; Chen, Yueh-Sheng; Chang, Yung-Ming; Huang, Chih-Yang

2015-01-01

Alpinia oxyphylla MIQ (Alpinate Oxyphyllae Fructus, AOF) is an important traditional Chinese medicinal herb whose fruits is widely used to prepare tonics and is used as an aphrodisiac, anti salivary, anti diuretic and nerve-protective agent. Protocatechuic acid (PCA), a simple phenolic compound was isolated from the kernels of AOF. This study investigated the role of PCA in promoting neural regeneration and the underlying molecular mechanisms. Nerve regeneration is a complex physiological response that takes place after injury. Schwann cells play a crucial role in the endogenous repair of peripheral nerves due to their ability to proliferate and migrate. The role of PCA in Schwann cell migration was determined by assessing the induced migration potential of RSC96 Schwann cells. PCA induced changes in the expression of proteins of three MAPK pathways, as determined using Western blot analysis. In order to determine the roles of MAPK (ERK1/2, JNK, and p38) pathways in PCA-induced matrix-degrading proteolytic enzyme (PAs and MMP2/9) production, the expression of several MAPK-associated proteins was analyzed after siRNA-mediated inhibition assays. Treatment with PCA-induced ERK1/2, JNK, and p38 phosphorylation that activated the downstream expression of PAs and MMPs. PCA-stimulated ERK1/2, JNK and p38 phosphorylation was attenuated by individual pretreatment with siRNAs or MAPK inhibitors (U0126, SP600125, and SB203580), resulting in the inhibition of migration and the uPA-related signal pathway. Taken together, our data suggest that PCA extract regulate the MAPK (ERK1/2, JNK, and p38)/PA (uPA, tPA)/MMP (MMP2, MMP9) mediated regeneration and migration signaling pathways in Schwann cells. Therefore, PCA plays a major role in Schwann cell migration and the regeneration of damaged peripheral nerve.

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

PubMed Central

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

2016-01-01

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

TGFβ pathway limits dedifferentiation following WNT and MAPK pathway activation to suppress intestinal tumourigenesis

PubMed Central

Cammareri, Patrizia; Vincent, David F; Hodder, Michael C; Ridgway, Rachel A; Murgia, Claudio; Nobis, Max; Campbell, Andrew D; Varga, Julia; Huels, David J; Subramani, Chithra; Prescott, Katie L H; Nixon, Colin; Hedley, Ann; Barry, Simon T; Greten, Florian R; Inman, Gareth J; Sansom, Owen J

2017-01-01

Recent studies have suggested increased plasticity of differentiated cells within the intestine to act both as intestinal stem cells (ISCs) and tumour-initiating cells. However, little is known of the processes that regulate this plasticity. Our previous work has shown that activating mutations of Kras or the NF-κB pathway can drive dedifferentiation of intestinal cells lacking Apc. To investigate this process further, we profiled both cells undergoing dedifferentiation in vitro and tumours generated from these cells in vivo by gene expression analysis. Remarkably, no clear differences were observed in the tumours; however, during dedifferentiation in vitro we found a marked upregulation of TGFβ signalling, a pathway commonly mutated in colorectal cancer (CRC). Genetic inactivation of TGFβ type 1 receptor (Tgfbr1/Alk5) enhanced the ability of KrasG12D/+ mutation to drive dedifferentiation and markedly accelerated tumourigenesis. Mechanistically this is associated with a marked activation of MAPK signalling. Tumourigenesis from differentiated compartments is potently inhibited by MEK inhibition. Taken together, we show that tumours arising in differentiated compartments will be exposed to different suppressive signals, for example, TGFβ and blockade of these makes tumourigenesis more efficient from this compartment. PMID:28622298

Genome-wide DNA methylation analysis in lung fibroblasts co-cultured with silica-exposed alveolar macrophages.

PubMed

Li, Juan; Yao, Wu; Zhang, Lin; Bao, Lei; Chen, Huiting; Wang, Di; Yue, Zhongzheng; Li, Yiping; Zhang, Miao; Hao, Changfu

2017-05-12

Exposure to crystalline silica is considered to increase the risk of lung fibrosis. The primary effector cell, the myofibroblast, plays an important role in the deposition of extracellular matrix (ECM). DNA methylation change is considered to have a potential effect on myofibroblast differentiation. Therefore, the present study was designed to investigate the genome-wide DNA methylation profiles of lung fibroblasts co-cultured with alveolar macrophages exposed to crystalline silica in vitro. AM/fibroblast co-culture system was established. CCK8 was used to assess the toxicity of AMs. mRNA and protein expression of collagen I, α-SMA, MAPK9 and TGF-β1 of fibroblasts after AMs exposed to 100 μg /ml SiO 2 for 0-, 24-, or 48 h were determined by means of quantitative real-time PCR, immunoblotting and immunohistochemistry. Genomic DNA of fibroblasts was isolated using MeDIP-Seq to sequence. R software, GO, KEGG and Cytoscape were used to analyze the data. SiO 2 exposure increased the expression of collagen I and α-SMA in fibroblasts in co-culture system. Analysis of fibroblast methylome identified extensive methylation changes involved in several signaling pathways, such as the MAPK signaling pathway and metabolic pathways. Several candidates, including Tgfb1 and Mapk9, are hubs who can connect the gene clusters. MAPK9 mRNA expression was significantly higher in fibroblast exposed to SiO 2 in co-culture system for 48 h. MAPK9 protein expression was increased at both 24-h and 48-h treatment groups. TGF-β1 mRNA expression of fibroblast has a time-dependent manner, but we didn't observe the TGF-β1 protein expression. Tgfb1 and Mapk9 are helpful to explore the mechanism of myofibroblast differentiation. The genome-wide DNA methylation profiles of fibroblasts in this experimental silicosis model will be useful for future studies on epigenetic gene regulation during myofibroblast differentiation.

Osthole exhibits anti-cancer property in rat glioma cells through inhibiting PI3K/Akt and MAPK signaling pathways.

PubMed

Ding, Daofang; Wei, Songpu; Song, Yi; Li, Linghui; Du, Guoqing; Zhan, Hongsheng; Cao, Yuelong

2013-01-01

The purpose of this study was to investigate how Osthole affects glioma cell proliferation, apoptosis, invasion and migration. Rat glioma cells were treated with different concentrations of Osthole (0 µM, 25 µM, 50 µM, and 100 µM). Cell proliferation was assessed by measuring PCNA expression and CCK8 assay at different time points. Apoptosis was evaluated by measuring the expression of pro-apoptotic protein including Bax, Bcl2, PARP, and cleaved Caspase3, and of anti-apoptotic protein Survivin. Cell migration and invasion were assessed using different methods. Signaling pathways such as PI3K/Akt and MAPK, which are involved in the development of glioma cells, were also investigated in this study. Treatment with Osthole markedly inhibits glioma cell proliferation, as assessed by western blot with the PCNA antibody. Osthole also induces cell apoptosis by upregulating the expression of pro-apoptotic proteins, and by reducing the expression of anti-apoptotic factors. Moreover, C6 cell migration and invasion were efficiently inhibited in groups treated with Osthole, compared to the control group. Additionally, inhibition of PI3K/Akt and MAPK signaling pathway was also observed in C6 cells treated with Osthole. Our findings showed an anti-cancer effect of Osthole on glioma cells, including the proliferation inhibition, apoptosis induction, and migration/invasion inhibition. Further investigation in C6 glioma cells implicated the role of Osthole in essential pathways controlling glioma cell progression. Taken together, our data suggested that Osthole may have a potential application in glioma therapy. © 2014 S. Karger AG, Basel.

The synergistic antitumor activity of arsenic trioxide and vitamin K2 in HL-60 cells involves increased ROS generation and regulation of the ROS-dependent MAPK signaling pathway.

PubMed

Qu, Hui; Tong, Danan; Zhang, Yanqing; Kang, Kai; Zhang, Yuling; Chen, Lan; Ren, Lihong

2013-10-01

The aim of this study was to investigate the synergistic anticancer effects of arsenic trioxide (ATO) and vitamin K2 (VK2) in HL-60 cells, and elucidate the potential mechanisms. HL-60 cells were exposed to ATO and VK2, either alone or in combination. Cell proliferation and apoptosis were assessed. The combination index (CI) method was used to evaluate whether the action of the drug combination was synergistic, additive or antagonistic. Reactive oxygen species (ROS) and the mitogen-activated protein kinase (MAPK) signaling pathway were also studied, to provide insight into potential mechanisms. The results showed that combining ATO with VK2 significantly inhibited HL-60 cell growth more than either agent alone, indicating a synergistic effect with CI < 1. Annexin V staining demonstrated that the inhibition of cell growth by the drug combination was mediated through an increase in apoptosis; this was supported by examination of caspase-3 and caspase-9 with Western blot assays. Furthermore, induction of ROS, and phosphorylation and activation of the JNK and p38 (but not ERK1/2) pathways, was observed in cells administered the drug combination. Prior treatment with the antioxidant, N-acetylcysteine, partly blocked the apoptosis and expression of caspase-3 induced by the drug combination; apoptosis and expression of caspase-3 were also reversed by inhibitors of JNK or p38. These results suggest that ATO and VK2 act synergistically to increase HL-60 cell apoptosis, through ROS generation and regulation of the MAPK signaling pathway.

Assigning Quantitative Function to Post-Translational Modifications Reveals Multiple Sites of Phosphorylation That Tune Yeast Pheromone Signaling Output

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

Pincus, David; Ryan, Christopher J.; Smith, Richard D.

2013-03-12

Cell signaling systems transmit information by post-­translationally modifying signaling proteins, often via phosphorylation. While thousands of sites of phosphorylation have been identified in proteomic studies, the vast majority of sites have no known function. Assigning functional roles to the catalog of uncharacterized phosphorylation sites is a key research challenge. Here we present a general approach to address this challenge and apply it to a prototypical signaling pathway, the pheromone response pathway in Saccharomyces cerevisiae. The pheromone pathway includes a mitogen activated protein kinase (MAPK) cascade activated by a G-­protein coupled receptor (GPCR). We used mass spectrometry-based proteomics to identify sitesmore » whose phosphorylation changed when the system was active, and evolutionary conservation to assign priority to a list of candidate MAPK regulatory sites. We made targeted alterations in those sites, and measured the effects of the mutations on pheromone pathway output in single cells. Our work identified six new sites that quantitatively tuned system output. We developed simple computational models to find system architectures that recapitulated the quantitative phenotypes of the mutants. Our results identify a number of regulated phosphorylation events that contribute to adjust the input-­output relationship of this model eukaryotic signaling system. We believe this combined approach constitutes a general means not only to reveal modification sites required to turn a pathway on and off, but also those required for more subtle quantitative effects that tune pathway output. Our results further suggest that relatively small quantitative influences from individual regulatory phosphorylation events endow signaling systems with plasticity that evolution may exploit to quantitatively tailor signaling outcomes.« less

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

Lysophosphatidylcholine up-regulates human endothelial nitric oxide synthase gene transactivity by c-Jun N-terminal kinase signalling pathway

PubMed Central

Xing, Feiyue; Liu, Jing; Mo, Yongyan; Liu, Zhifeng; Qin, Qinghe; Wang, Jingzhen; Fan, Zhenhua; Long, Yutian; Liu, Na; Zhao, Kesen; Jiang, Yong

2009-01-01

Human endothelial nitric oxide synthase (eNOS) plays a pivotal role in maintaining blood pressure homeostasis and vascular integrity. It has recently been reported that mitogen-activated protein kinases (MAPKs) are intimately implicated in expression of eNOS. However detailed mechanism mediated by them remains to be clarified. In this study, eNOS gene transactivity in human umbilical vein endothelial cells was up-regulated by stimulation of lysophosphatidylcholine (LPC). The stimulation of LPC highly activated both extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK), with differences in the dynamic processes of activation between them. Unexpectedly, p38 MAPK could not be activated by the stimulation of LPC. The activation of JNK signalling pathway by overexpression of JNK or its upstream kinase active mutant up-regulated the transactivity of eNOS significantly, but the activation of p38 signalling pathway down-regulated it largely. The inhibition of either ERK1/2 or JNK signalling pathway by kinase-selective inhibitors could markedly block the induction of the transactivity by LPC. It was observed by electrophoretic mobility shift assay that LPC stimulated both SP1 and AP1 DNA binding activity to go up. Additionally using decoy oligonucleotides proved that SP1 was necessary for maintaining the basal or stimulated transactivity, whereas AP1 contributed mainly to the increase of the stimulated transactivity. These findings indicate that the up-regulation of the eNOS gene transactivity by LPC involves the enhancement of SP1 transcription factor by the activation of JNK and ERK1/2 signalling pathways and AP1 transcription factor by the activation of JNK signalling pathway. PMID:18624763

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.

Sampling-based Bayesian approaches reveal the importance of quasi-bistable behavior in cellular decision processes on the example of the MAPK signaling pathway in PC-12 cell lines.

PubMed

Jensch, Antje; Thomaseth, Caterina; Radde, Nicole E

2017-01-25

Positive and negative feedback loops are ubiquitous motifs in biochemical signaling pathways. The mitogen-activated protein kinase (MAPK) pathway module is part of many distinct signaling networks and comprises several of these motifs, whose functioning depends on the cell line at hand and on the particular context. The maintainance of specificity of the response of the MAPK module to distinct stimuli has become a key paradigm especially in PC-12 cells, where the same module leads to different cell fates, depending on the stimulating growth factor. This cell fate is regulated by differences in the ERK (MAPK) activation profile, which shows a transient response upon stimulation with EGF, while the response is sustained in case of NGF. This behavior was explained by different effective network topologies. It is widely believed that this sustained response requires a bistable system. In this study we present a sampling-based Bayesian model analysis on a dataset, in which PC-12 cells have been stimulated with different growth factors. This is combined with novel analysis methods to investigate the role of feedback interconnections to shape ERK response. Results strongly suggest that, besides bistability, an additional effect called quasi-bistability can contribute to explain the observed responses of the system to different stimuli. Quasi-bistability is the ability of a monostable system to maintain two distinct states over a long time period upon a transient signal, which is also related to positive feedback, but cannot be detected by standard steady state analysis methods. Although applied on a specific example, our framework is generic enough to be also relevant for other regulatory network modeling studies that comprise positive feedback to explain cellular decision making processes. Overall, this study advices to focus not only on steady states, but also to take transient behavior into account in the analysis.

Cell-free extracts of Propionibacterium acnes stimulate cytokine production through activation of p38 MAPK and Toll-like receptor in SZ95 sebocytes.

PubMed

Huang, Yu-Chun; Yang, Chao-Hsun; Li, Ting-Ting; Zouboulis, Christos C; Hsu, Han-Chi

2015-10-15

Propionibacterium acnes has been considered to influence the acne lesions. The present study intended to elucidate the underlying signaling pathways of P. acnes in human sebaceous gland cells relative to the generation of proinflammatory cytokines. Cell-free extracts of P. acnes under stationary growth phase were co-incubated with human immortalized SZ95 sebocytes. Then, cell-free P. acnes extracts-induced cytokine expression was evaluated by measuring mRNA and protein levels using quantitative RT-PCR and ELISA. Changes of phosphorylated cell signaling proteins and transcription factors were measured by Western blots and Milliplex assay. The interactive molecular mechanisms of P. acnes and sebocytes were examined through use of shRNA and the specific inhibitors of signaling pathways. Cell-free extracts of P. acnes significantly stimulated secretion of interleukin (IL)-8 and IL-6 in SZ95 sebocytes. The degradation of IκB-α and increased phosphorylation of IκB-α, p38 mitogen activated protein kinase (MAPK), CREB, and STAT3 were demonstrated. Quantitative RT-PCR measurements revealed that gene expression of IL-8 and Toll-like receptor 2 (TLR2) was enhanced by cell-free extracts of P. acnes. In addition, the NF-κB inhibitor BMS345541, p38 MAPK inhibitor SB203580, or anti-TLR2 neutralizing antibody prevented cell-free P. acnes extracts-induced secretion of IL-8. Knockdown of TLR2 using shRNA exerted similar inhibitory effects on IL-8 expression. Moreover, inhibition of STAT3 activity by STA-21 enhanced P. acnes-mediated secretion of IL-8. Cell-free extracts of P. acnes are capable to activate NF-κB and p38 MAPK pathways and up-regulate secretion of IL-8 through TLR2-dependent signaling in human SZ95 sebocytes. Copyright © 2015 Elsevier Inc. All rights reserved.

Acrylamide-induced oxidative stress and inflammatory response are alleviated by N-acetylcysteine in PC12 cells: Involvement of the crosstalk between Nrf2 and NF-κB pathways regulated by MAPKs.

PubMed

Pan, Xiaoqi; Wu, Xu; Yan, Dandan; Peng, Cheng; Rao, Chaolong; Yan, Hong

2018-05-15

Acrylamide (ACR) is a classic neurotoxin in animals and humans. However, the mechanism underlying ACR neurotoxicity remains controversial, and effective prevention and treatment measures against this condition are scarce. This study focused on clarifying the crosstalk between the involved signaling pathways in ACR-induced oxidative stress and inflammatory response and investigating the protective effect of antioxidant N-acetylcysteine (NAC) against ACR in PC12 cells. Results revealed that ACR exposure led to oxidative stress characterized by significant increase in reactive oxygen species (ROS) and malondialdehyde (MDA) levels and glutathione (GSH) consumption. Inflammatory response was observed based on the dose-dependently increased levels of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6). NAC attenuated ACR-induced enhancement of MDA and ROS levels and TNF-α generation. In addition, ACR activated nuclear transcription factor E2-related factor 2 (Nrf2) and nuclear factor-κB (NF-κB) signaling pathways. Knockdown of Nrf2 by siRNA significantly blocked the increased NF-κB p65 protein expression in ACR-treated PC12 cells. Down-regulation of NF-κB by specific inhibitor BAY11-7082 similarly reduced ACR-induced increase in Nrf2 protein expression. NAC treatment increased Nrf2 expression and suppressed NF-κB p65 expression to ameliorate oxidative stress and inflammatory response caused by ACR. Further results showed that mitogen-activated protein kinases (MAPKs) pathway was activated prior to the activation of Nrf2 and NF-κB pathways. Inhibition of MAPKs blocked Nrf2 and NF-κB pathways. Collectively, ACR activated Nrf2 and NF-κB pathways which were regulated by MAPKs. A crosstalk between Nrf2 and NF-κB pathways existed in ACR-induced cell damage. NAC protected against oxidative damage and inflammatory response induced by ACR by activating Nrf2 and inhibiting NF-κB pathways in PC12 cells. Copyright © 2018 Elsevier B.V. All rights reserved.

ACTIVATION OF THE EGF RECEPTOR SIGNALING PATHWAY IN HUMAN AIRWAY EPITHELIAL CELLS EXPOSED TO METALS

EPA Science Inventory

We have previously shown that exposure to combustion-derived metals rapidly (within 20 min) activated mitogen-activated protein kinases (MAPK), including extracellular signal-regulated kinase (ERK), in the human bronchial epithelial cell line BEAS. To study the mechanisms respons...

Dabrafenib; Preclinical Characterization, Increased Efficacy when Combined with Trametinib, while BRAF/MEK Tool Combination Reduced Skin Lesions

PubMed Central

King, Alastair J.; Arnone, Marc R.; Bleam, Maureen R.; Moss, Katherine G.; Yang, Jingsong; Fedorowicz, Kelly E.; Smitheman, Kimberly N.; Erhardt, Joseph A.; Hughes-Earle, Angela; Kane-Carson, Laurie S.; Sinnamon, Robert H.; Qi, Hongwei; Rheault, Tara R.; Uehling, David E.; Laquerre, Sylvie G.

2013-01-01

Mitogen-Activated Protein Kinase (MAPK) pathway activation has been implicated in many types of human cancer. BRAF mutations that constitutively activate MAPK signalling and bypass the need for upstream stimuli occur with high prevalence in melanoma, colorectal carcinoma, ovarian cancer, papillary thyroid carcinoma, and cholangiocarcinoma. In this report we characterize the novel, potent, and selective BRAF inhibitor, dabrafenib (GSK2118436). Cellular inhibition of BRAFV600E kinase activity by dabrafenib resulted in decreased MEK and ERK phosphorylation and inhibition of cell proliferation through an initial G1 cell cycle arrest, followed by cell death. In a BRAFV600E-containing xenograft model of human melanoma, orally administered dabrafenib inhibited ERK activation, downregulated Ki67, and upregulated p27, leading to tumor growth inhibition. However, as reported for other BRAF inhibitors, dabrafenib also induced MAPK pathway activation in wild-type BRAF cells through CRAF (RAF1) signalling, potentially explaining the squamous cell carcinomas and keratoacanthomas arising in patients treated with BRAF inhibitors. In addressing this issue, we showed that concomitant administration of BRAF and MEK inhibitors abrogated paradoxical BRAF inhibitor-induced MAPK signalling in cells, reduced the occurrence of skin lesions in rats, and enhanced the inhibition of human tumor xenograft growth in mouse models. Taken together, our findings offer preclinical proof of concept for dabrafenib as a specific and highly efficacious BRAF inhibitor and provide evidence for its potential clinical benefits when used in combination with a MEK inhibitor. PMID:23844038

Resveratrol inhibits LPS-induced mice mastitis through attenuating the MAPK and NF-κB signaling pathway.

PubMed

Zhang, Xu; Wang, Yanan; Xiao, Chong; Wei, Zhengkai; Wang, Jingjing; Yang, Zhengtao; Fu, Yunhe

2017-06-01

Resveratrol is a natural polyphenol extracted from mangy plants. It has been reported that resveratrol show multitudinous positive role in biology such as anti-oxidant, anti-nociception and anti-inflammatory effects. Therefore, the present study devotes to test the effect of resveratrol on LPS-induced mastitis in mice. Resveratrol was administered intraperitoneally 1 h before LPS treatment. And the anti-inflammatory effect of resveratrol was measured by histopathological examination, MPO assay, real-time PCR and western blotting analysis. The results showed that resveratrol significantly reduced the LPS-induced mammary histopathological changes. Meanwhile, it sharply attenuated the activity of MPO. The result also indicated that the resveratrol can decrease the expression of pro-inflammatory cytokines TNF-α and IL-1β. From the results of western blotting, resveratrol suppressed the expression of phosphorylation of p65 and IκB from NF-κB signal pathway and phosphorylation of p38 and ERK from MAPK signal pathway. These findings suggested that resveratrol may inhibit the inflammatory response in the mastitis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ecdysteroidogenesis and development in Heliothis virescens (Lepidoptera: Noctuidae): Focus on PTTH-stimulated pathways.

PubMed

Scieuzo, Carmen; Nardiello, Marisa; Salvia, Rosanna; Pezzi, Marco; Chicca, Milvia; Leis, Marilena; Bufo, Sabino A; Vinson, S Bradleigh; Rao, Asha; Vogel, Heiko; Falabella, Patrizia

2018-02-15

Post-embryonic development and molting in insects are regulated by endocrine changes, including prothoracicotropic hormone (PTTH)-stimulated ecdysone secretion by the prothoracic glands (PGs). In Lepidoptera, two pathways are potentially involved in PTTH-stimulated ecdysteroidogenesis, mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase/protein kinase B/target of rapamycin (PI3K/Akt/TOR). We investigated the potential roles of both these pathways in Heliothis virescens ecdysteroidogenesis. We identified putative proteins belonging to MAPK and PI3K/Akt/TOR signaling cascades, using transcriptomic analyses of PGs from last (fifth) instar larvae. Using western blots, we measured the phosphorylation of 4E-BP and S6K proteins, the main targets of TOR, following the in vitro exposure of PGs to brain extract containing PTTH (hereafter referred to as PTTH) and/or the inhibitors of MAPK (U0126), PI3K (LY294002) or TOR (rapamycin). Next, we measured ecdysone production, under the same experimental conditions, by enzyme immunoassay (EIA). We found that in Heliothis virescens last instar larvae, both pathways modulated PTTH-stimulated ecdysteroidogenesis. Finally, we analyzed the post-embryonic development of third and fourth instar larvae fed on diet supplemented with rapamycin, in order to better understand the role of the TOR pathway in larval growth. When rapamycin was added to the diet of larvae, the onset of molting was delayed, the growth rate was reduced and abnormally small larvae/pupae with high mortality rates resulted. In larvae fed on diet supplemented with rapamycin, the growth of PGs was suppressed, and ecdysone production and secretion were inhibited. Overall, the in vivo and in vitro results demonstrated that, similarly to Bombyx mori, MAPK and PI3K/Akt/TOR pathways are involved in PTTH signaling-stimulated ecdysteroidogenesis, and indicated the important role of TOR protein in H. virescens systemic growth. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cardiac fibrosis and dysfunction in experimental diabetic cardiomyopathy are ameliorated by alpha-lipoic acid.

PubMed

Li, Chun-jun; Lv, Lin; Li, Hui; Yu, De-min

2012-06-19

Alpha-lipoic acid (ALA), a naturally occurring compound, exerts powerful protective effects in various cardiovascular disease models. However, its role in protecting against diabetic cardiomyopathy (DCM) has not been elucidated. In this study, we have investigated the effects of ALA on cardiac dysfunction, mitochondrial oxidative stress (MOS), extracellular matrix (ECM) remodeling and interrelated signaling pathways in a diabetic rat model. Diabetes was induced in rats by I.V. injection of streptozotocin (STZ) at 45 mg/kg. The animals were randomly divided into 4 groups: normal groups with or without ALA treatment, and diabetes groups with or without ALA treatment. All studies were carried out 11 weeks after induction of diabetes. Cardiac catheterization was performed to evaluate cardiac function. Mitochondrial oxidative biochemical parameters were measured by spectophotometeric assays. Extracellular matrix content (total collagen, type I and III collagen) was assessed by staining with Sirius Red. Gelatinolytic activity of Pro- and active matrix metalloproteinase-2 (MMP-2) levels were analyzed by a zymogram. Cardiac fibroblasts differentiation to myofibroblasts was evaluated by Western blot measuring smooth muscle actin (α-SMA) and transforming growth factor-β (TGF-β). Key components of underlying signaling pathways including the phosphorylation of c-Jun N-terminal kinase (JNK), p38 MAPK and ERK were also assayed by Western blot. DCM was successfully induced by the injection of STZ as evidenced by abnormal heart mass and cardiac function, as well as the imbalance of ECM homeostasis. After administration of ALA, left ventricular dysfunction greatly improved; interstitial fibrosis also notably ameliorated indicated by decreased collagen deposition, ECM synthesis as well as enhanced ECM degradation. To further assess the underlying mechanism of improved DCM by ALA, redox status and cardiac remodeling associated signaling pathway components were evaluated. It was shown that redox homeostasis was disturbed and MAPK signaling pathway components activated in STZ-induced DCM animals. While ALA treatment favorably shifted redox homeostasis and suppressed JNK and p38 MAPK activation. These results, coupled with the excellent safety and tolerability profile of ALA in humans, demonstrate that ALA may have therapeutic potential in the treatment of DCM by attenuating MOS, ECM remodeling and JNK, p38 MAPK activation.

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

The enhancement of stress-related memory by glucocorticoids depends on synapsin-Ia/Ib

PubMed Central

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

2010-01-01

The activation of glucocorticoid receptors (GR) by glucocorticoids increases stress-related memory through the activation of the MAPK signaling pathway and the downstream transcription factor Egr-1. Here, using converging in vitro and in vivo approaches, respectively, GR-expressing cell lines, culture of hippocampal neurons, and GR genetically modified mice (GRNesCre), we identified synapsin-Ia/Ib as one of the effectors of the glucocorticoid signaling cascade. Stress and glucocorticoid-induced activation of the GR modulate synapsin-Ia/Ib through two complementary mechanisms. First, glucocorticoids driving Egr-1 expression increase the expression of synapsin-Ia/Ib, and second, glucocorticoids driving MAPK activation increase its phosphorylation. Finally, we showed that blocking fucosylation of synapsin-Ia/Ib in the hippocampus inhibits its expression and prevents the glucocorticoid-mediated increase in stress-related memory. In conclusion, our data provide a complete molecular pathway (GR/Egr-1/MAPK/Syn-Ia/Ib) through which stress and glucocorticoids enhance the memory of stress-related events and highlight the function of synapsin-Ia/Ib as molecular effector of the behavioral effects of stress. PMID:20368707

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

Upregulation of eIF-5A1 in the paralyzed muscle after spinal cord transection associates with spontaneous hindlimb locomotor recovery in rats by upregulation of the ErbB, MAPK and neurotrophin signal pathways.

PubMed

Shang, Fei-Fei; Zhao, Wei; Zhao, Qi; Liu, Jia; Li, Da-Wei; Zhang, Hua; Zhou, Xin-Fu; Li, Cheng-Yun; Wang, Ting-Hua

2013-10-08

It is well known that trauma is frequently accompanied by spontaneous functional recovery after spinal cord injury (SCI), but the underlying mechanisms remain elusive. In this study, BBB scores showed a gradual return of locomotor functions after SCT. Proteomics analysis revealed 16 differential protein spots in the gastrocnemius muscle between SCT and normal rats. Of these differential proteins, eukaryotic translation initiation factor 5A1 (elf-5A1), a highly conserved molecule throughout eukaryotes, exhibited marked upregulation in the gastrocnemius muscle after SCT. To study the role of eIF-5A1 in the restoration of hindlimb locomotor functions following SCT, we used siRNA to downregulate the mRNA level of eIF-5A1. Compared with untreated SCT control rats, those subjected to eIF-5A1 knockdown exhibited impaired functional recovery. Moreover, gene expression microarrays and bioinformatic analysis showed high correlation between three main signal pathways (ErbB, MAPK and neurotrophin signal pathways) and eIF-5A1. These signal pathways regulate cell proliferation, differentiation and neurocyte growth. Consequently, eIF-5A1 played a pivotal role via these signal pathways in hindlimb locomotor functional recovery after SCT, which could pave the way for the development of a new strategy for the treatment of spinal cord injury in clinical trials. Copyright © 2012. Published by Elsevier B.V.

Caveolin 3-mediated integrin β1 signaling is required for the proliferation of folliculostellate cells in rat anterior pituitary gland under the influence of extracellular matrix.

PubMed

Horiguchi, Kotaro; Fujiwara, Ken; Ilmiawati, Cimi; Kikuchi, Motoshi; Tsukada, Takehiro; Kouki, Tom; Yashiro, Takashi

2011-07-01

Folliculostellate (FS) cells in the anterior pituitary gland are believed to have multifunctional properties. Using transgenic rats that express green fluorescent protein (GFP) specifically in FS cells in the anterior pituitary gland (S100b-GFP rats), we recently revealed that FS cells in primary culture exhibited marked proliferation in the presence of laminin, an extracellular matrix (ECM) component of the basement membrane. In a process referred to as matricrine action, FS cells receive ECM as a signal through their receptors, which results in morphological and functional changes. In this study, we investigated matricrine signaling in FS cells and observed that the proliferation of FS cells is mediated by integrin β1, which is involved in various signaling pathways for cell migration and proliferation in response to ECM. Then, we analyzed downstream events of the integrin β1 signaling pathway in the proliferation of FS cells and identified caveolin 3 as a potential candidate molecule. Caveolin 3 is a membrane protein that binds cholesterol and a number of signaling molecules that interact with integrin β1. Using specific small interfering RNA of caveolin 3, the proliferation of FS cells was inhibited. Furthermore, caveolin 3 drove activation of the mitogen-activated protein kinase (MAPK) signaling cascades, which resulted in upregulation of cyclin D1 in FS cells. These findings suggest that matricrine signaling in the proliferation of FS cells was transduced by a caveolin 3-mediated integrin β1 signaling pathway and subsequent activation of the MAPK pathway. © 2011 Society for Endocrinology

Benzo[a]pyrene activates an AhR/Src/ERK axis that contributes to CYP1A1 induction and stable DNA adducts formation in lung cells.

PubMed

Vázquez-Gómez, G; Rocha-Zavaleta, L; Rodríguez-Sosa, M; Petrosyan, P; Rubio-Lightbourn, J

2018-06-01

Benzo[a]pyrene (B[a]P), the most extensively studied carcinogen in cigarette smoke, has been regarded as a critical mediator of lung cancer. It is known that B[a]P-mediated Aryl hydrocarbon Receptor (AhR) activation stimulates the mitogen activated protein kinases (MAPK) signaling cascade in different cell models. MAPK pathway disturbances drive alterations in cellular processes, such as differentiation, proliferation, and apoptosis, and the disturbances may also modify the AhR pathway itself. However, MAPK involvement in B[a]P metabolic activation and toxicity in lung tissues is not well understood. Here, we used a non-transformed human bronchial epithelial lung cell line, BEAS-2B, to study the participation of ERK 1/2 kinases in the metabolic activation of B[a]P and in its related genotoxic effects. Our results indicate that B[a]P is not cytotoxic to BEAS-2B cells at relatively low concentrations, but it enhances CYP1A1 gene transcription and protein induction. Additionally, B[a]P promotes Src and ERK 1/2 phosphorylation. Accordingly, inhibition of both Src and ERK 1/2 phosphorylation decreases CYP1A1 protein induction, AhR nuclear translocation and production of B[a]P adducts. Together, these data suggest a crosstalk between AhR and the members of the MAPK pathway, ERK 1/2 mediated by Src kinase. This interaction is important for the adequate AhR pathway signaling that in turn induces transcription and protein induction of CYP1A1 and B[a]P-induced DNA damage in BEAS-2B cells. Copyright © 2018 Elsevier B.V. All rights reserved.

TNF{alpha} acting on TNFR1 promotes breast cancer growth via p42/P44 MAPK, JNK, Akt and NF-{kappa}B-dependent pathways

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

Rivas, Martin A.; Carnevale, Romina P.; Proietti, Cecilia J.

2008-02-01

Tumor necrosis factor {alpha} (TNF{alpha}) enhances proliferation of chemically-induced mammary tumors and of T47D human cell line through not fully understood pathways. Here, we explored the intracellular signaling pathways triggered by TNF{alpha}, the participation of TNF{alpha} receptor (TNFR) 1 and TNFR2 and the molecular mechanism leading to breast cancer growth. We demonstrate that TNF{alpha} induced proliferation of C4HD murine mammary tumor cells and of T47D cells through the activation of p42/p44 MAPK, JNK, PI3-K/Akt pathways and nuclear factor-kappaB (NF-{kappa}B) transcriptional activation. A TNF{alpha}-specific mutein selectively binding to TNFR1 induced p42/p44 MAPK, JNK, Akt activation, NF-{kappa}B transcriptional activation and cell proliferation,more » just like wild-type TNF{alpha}, while a mutein selective for TNFR2 induced only p42/p44 MAPK activation. Interestingly, blockage of TNFR1 or TNFR2 with specific antibodies was enough to impair TNF{alpha} signaling and biological effect. Moreover, in vivo TNF{alpha} administration supported C4HD tumor growth. We also demonstrated, for the first time, that injection of a selective inhibitor of NF-{kappa}B activity, Bay 11-7082, resulted in regression of TNF{alpha}-promoted tumor. Bay 11-7082 blocked TNF{alpha} capacity to induce cell proliferation and up-regulation of cyclin D1 and of Bcl-x{sub L}in vivo and in vitro. Our results reveal evidence for TNF{alpha} as a breast tumor promoter, and provide novel data for a future therapeutic approach using TNF{alpha} antagonists and NF-{kappa}B pharmacological inhibitors in established breast cancer treatment.« less

Probiotic lactobacillus and estrogen effects on vaginal epithelial gene expression responses to Candida albicans.

PubMed

Wagner, R Doug; Johnson, Shemedia J

2012-06-20

Vaginal epithelial cells have receptors, signal transduction mechanisms, and cytokine secretion capabilities to recruit host defenses against Candida albicans infections. This research evaluates how probiotic lactobacilli affect the defensive epithelial response. This study used quantitative reverse transcription-polymerase chain reaction assay (qRT-PCR), flow cytometry, and a multiplex immunoassay to observe changes in the regulation of gene expression related to cytokine responses in the VK2 (E6/E7) vaginal epithelial cell line treated with 17β-estradiol, exposed to probiotic Lactobacillus rhamnosus GR-1® and Lactobacillus reuteri RC-14® and challenged with C. albicans. Data were statistically evaluated by repeated measures analysis of variance and paired t-tests where appropriate. C. albicans induced mRNA expression of genes related to inflammatory cytokine responses associated with nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signal transduction pathways. 17β-estradiol suppressed expression of interleukin-1α (IL-1α), IL-6, IL-8, and tumor necrosis factor alpha (TNFα) mRNA. Probiotic lactobacilli suppressed C. albicans-induced nuclear factor-kappa B inhibitor kinase kinase alpha (Iκκα), Toll-like receptor-2 (TLR2), TLR6, IL-8, and TNFα, also suggesting inhibition of NF-κB signaling. The lactobacilli induced expression of IL-1α, and IL-1β mRNA, which was not inhibited by curcumin, suggesting that they induce an alternate inflammatory signal transduction pathway to NF-κB, such as the mitogen activated protein kinase and activator protein-1 (MAPK/AP-1) signal transduction pathway. Curcumin inhibited IL-13 secretion, suggesting that expression of this cytokine is mainly regulated by NF-κB signaling in VK2 cells. The results suggest that C. albicans infection induces pro-inflammatory responses in vaginal epithelial cells, and estrogen and lactobacilli suppress expression of NF-κB-related inflammatory genes. Probiotic lactobacilli may induce IL-1α and IL-1β expression by an alternate signal transduction pathway, such as MAPK/AP-1. Activation of alternate signaling mechanisms by lactobacilli to modify epithelial cell cytokine production may be a mechanism for probiotic modulation of morbidity in vulvovaginal candidiasis.

PI3K pathway mutations are associated with longer time to local progression after radioembolization of colorectal liver metastases.

PubMed

Ziv, Etay; Bergen, Michael; Yarmohammadi, Hooman; Boas, F Ed; Petre, E Nadia; Sofocleous, Constantinos T; Yaeger, Rona; Solit, David B; Solomon, Stephen B; Erinjeri, Joseph P

2017-04-04

To establish the relationship between common mutations in the MAPK and PI3K signaling pathways and local progression after radioembolization. Retrospective review of a HIPAA-compliant institutional review-board approved database identified 40 patients with chemo-refractory colorectal liver metastases treated with radioembolization who underwent tumor genotyping for hotspot mutations in 6 key genes in the MAPK/PI3K pathways (KRAS, NRAS, BRAF, MEK1, PIK3CA, and AKT1). Mutation status as well as clinical, tumor, and treatment variables were recorded. These factors were evaluated in relation to time to local progression (TTLP), which was calculated from time of radioembolization to first radiographic evidence of local progression. Predictors of outcome were identified using a proportional hazards model for both univariate and multivariate analysis with death as a competing risk. Sixteen patients (40%) had no mutations in either pathway, eighteen patients (45%) had mutations in the MAPK pathway, ten patients (25%) had mutations in the PI3K pathway and four patients (10%) had mutations in both pathways. The cumulative incidence of progression at 6 and 12 months was 33% and 55% for the PI3K mutated group compared with 76% and 92% in the PI3K wild type group. Mutation in the PI3K pathway was a significant predictor of longer TTLP in both univariate (p=0.031, sHR 0.31, 95% CI: 0.11-0.90) and multivariate (p=0.015, sHR=0.27, 95% CI: 0.096-0.77) analysis. MAPK pathway alterations were not associated with TTLP. PI3K pathway mutation predicts longer time to local progression after radioembolization of colorectal liver metastases.

Identification of a novel human kinase supporter of Ras (hKSR-2) that functions as a negative regulator of Cot (Tpl2) signaling.

PubMed

Channavajhala, Padma L; Wu, Leeying; Cuozzo, John W; Hall, J Perry; Liu, Wei; Lin, Lih-Ling; Zhang, Yuhua

2003-11-21

Kinase suppressor of Ras (KSR) is an integral and conserved component of the Ras signaling pathway. Although KSR is a positive regulator of the Ras/mitogen-activated protein (MAP) kinase pathway, the role of KSR in Cot-mediated MAPK activation has not been identified. The serine/threonine kinase Cot (also known as Tpl2) is a member of the MAP kinase kinase kinase (MAP3K) family that is known to regulate oncogenic and inflammatory pathways; however, the mechanism(s) of its regulation are not precisely known. In this report, we identify an 830-amino acid novel human KSR, designated hKSR-2, using predictions from genomic data base mining based on the structural profile of the KSR kinase domain. We show that, similar to the known human KSR, hKSR-2 co-immunoprecipitates with many signaling components of the Ras/MAPK pathway, including Ras, Raf, MEK-1, and ERK-1/2. In addition, we demonstrate that hKSR-2 co-immunoprecipitates with Cot and that co-expression of hKSR-2 with Cot significantly reduces Cot-mediated MAPK and NF-kappaB activation. This inhibition is specific to Cot, because Ras-induced ERK and IkappaB kinase-induced NF-kappaB activation are not significantly affected by hKSR-2 co-expression. Moreover, Cot-induced interleukin-8 production in HeLa cells is almost completely inhibited by the concurrent expression of hKSR-2, whereas transforming growth factor beta-activated kinase 1 (TAK1)/TAK1-binding protein 1 (TAB1)-induced interleukin-8 production is not affected by hKSR-2 co-expression. Taken together, these results indicate that hKSR-2, a new member of the KSR family, negatively regulates Cot-mediated MAP kinase and NF-kappaB pathway signaling.

Functional non-coding polymorphism in an EPHA2 promoter PAX2 binding site modifies expression and alters the MAPK and AKT pathways.

PubMed

Ma, Xiaoyin; Ma, Zhiwei; Jiao, Xiaodong; Hejtmancik, J Fielding

2017-08-30

To identify possible genetic variants influencing expression of EPHA2 (Ephrin-receptor Type-A2), a tyrosine kinase receptor that has been shown to be important for lens development and to contribute to both congenital and age related cataract when mutated, the extended promoter region of EPHA2 was screened for variants. SNP rs6603883 lies in a PAX2 binding site in the EPHA2 promoter region. The C (minor) allele decreased EPHA2 transcriptional activity relative to the T allele by reducing the binding affinity of PAX2. Knockdown of PAX2 in human lens epithelial (HLE) cells decreased endogenous expression of EPHA2. Whole RNA sequencing showed that extracellular matrix (ECM), MAPK-AKT signaling pathways and cytoskeleton related genes were dysregulated in EPHA2 knockdown HLE cells. Taken together, these results indicate a functional non-coding SNP in EPHA2 promoter affects PAX2 binding and reduces EPHA2 expression. They further suggest that decreasing EPHA2 levels alters MAPK, AKT signaling pathways and ECM and cytoskeletal genes in lens cells that could contribute to cataract. These results demonstrate a direct role for PAX2 in EPHA2 expression and help delineate the role of EPHA2 in development and homeostasis required for lens transparency.

Upregulation of CD147 promotes cell invasion, epithelial-to-mesenchymal transition and activates MAPK/ERK signaling pathway in colorectal cancer.

PubMed

Xu, Tao; Zhou, Mingliang; Peng, Lipan; Kong, Shuai; Miao, Ruizheng; Shi, Yulong; Sheng, Hongguang; Li, Leping

2014-01-01

Colorectal cancer (CRC) is one of the most common cancers in the world. CD147, a transmembrane protein, has been reported to be correlated with various cancers. In this study, we aimed to investigate the mechanism of CD147 in regulating drug resistance, cell invasion and epithelial-to-mesenchymal transition (EMT) in CRC cells. qRT-PCR and western blotting were used to evaluated the expression of CD147 in 40 CRC cases and 4 cell lines. Increased expression of CD147 at both mRNA and protein levels was found in CRC samples, and the level of CD147 was correlated with lymph node metastasis. CD147 overexpression increased the 5-Fluorouracil (5-FU) resistance, enhanced the invasion and EMT of CRC cells by regulating EMT markers and MMPs. Adverse results were obtained in CD147 knockdown CRC cell line. Further investigation revealed that CD147 activated MAPK/ERK pathway, ERK inhibitor U0126 suppressed the CD147-induced cell invasion, migration and MMP-2, MMP-9 expression. Taken together, our study indicates that CD147 promotes the 5-FU resistance, and MAPK/ERK signaling pathway is involved in CD147-promoted invasion and EMT of CRC cells.

Upregulation of CD147 promotes cell invasion, epithelial-to-mesenchymal transition and activates MAPK/ERK signaling pathway in colorectal cancer

PubMed Central

Xu, Tao; Zhou, Mingliang; Peng, Lipan; Kong, Shuai; Miao, Ruizheng; Shi, Yulong; Sheng, Hongguang; Li, Leping

2014-01-01

Colorectal cancer (CRC) is one of the most common cancers in the world. CD147, a transmembrane protein, has been reported to be correlated with various cancers. In this study, we aimed to investigate the mechanism of CD147 in regulating drug resistance, cell invasion and epithelial-to-mesenchymal transition (EMT) in CRC cells. qRT-PCR and western blotting were used to evaluated the expression of CD147 in 40 CRC cases and 4 cell lines. Increased expression of CD147 at both mRNA and protein levels was found in CRC samples, and the level of CD147 was correlated with lymph node metastasis. CD147 overexpression increased the 5-Fluorouracil (5-FU) resistance, enhanced the invasion and EMT of CRC cells by regulating EMT markers and MMPs. Adverse results were obtained in CD147 knockdown CRC cell line. Further investigation revealed that CD147 activated MAPK/ERK pathway, ERK inhibitor U0126 suppressed the CD147-induced cell invasion, migration and MMP-2, MMP-9 expression. Taken together, our study indicates that CD147 promotes the 5-FU resistance, and MAPK/ERK signaling pathway is involved in CD147-promoted invasion and EMT of CRC cells. PMID:25550778

OCD-like behavior is caused by dysfunction of thalamo-amygdala circuits and upregulated TrkB/ERK-MAPK signaling as a result of SPRED2 deficiency

PubMed Central

Ullrich, M; Weber, M; Post, A M; Popp, S; Grein, J; Zechner, M; Guerrero González, H; Kreis, A; Schmitt, A G; Üçeyler, N; Lesch, K-P; Schuh, K

2018-01-01

Obsessive-compulsive disorder (OCD) is a common neuropsychiatric disease affecting about 2% of the general population. It is characterized by persistent intrusive thoughts and repetitive ritualized behaviors. While gene variations, malfunction of cortico-striato-thalamo-cortical (CSTC) circuits, and dysregulated synaptic transmission have been implicated in the pathogenesis of OCD, the underlying mechanisms remain largely unknown. Here we show that OCD-like behavior in mice is caused by deficiency of SPRED2, a protein expressed in various brain regions and a potent inhibitor of Ras/ERK-MAPK signaling. Excessive self-grooming, reflecting OCD-like behavior in rodents, resulted in facial skin lesions in SPRED2 knockout (KO) mice. This was alleviated by treatment with the selective serotonin reuptake inhibitor fluoxetine. In addition to the previously suggested involvement of cortico-striatal circuits, electrophysiological measurements revealed altered transmission at thalamo-amygdala synapses and morphological differences in lateral amygdala neurons of SPRED2 KO mice. Changes in synaptic function were accompanied by dysregulated expression of various pre- and postsynaptic proteins in the amygdala. This was a result of altered gene transcription and triggered upstream by upregulated tropomyosin receptor kinase B (TrkB)/ERK-MAPK signaling in the amygdala of SPRED2 KO mice. Pathway overactivation was mediated by increased activity of TrkB, Ras, and ERK as a specific result of SPRED2 deficiency and not elicited by elevated brain-derived neurotrophic factor levels. Using the MEK inhibitor selumetinib, we suppressed TrkB/ERK-MAPK pathway activity in vivo and reduced OCD-like grooming in SPRED2 KO mice. Altogether, this study identifies SPRED2 as a promising new regulator, TrkB/ERK-MAPK signaling as a novel mediating mechanism, and thalamo-amygdala synapses as critical circuitry involved in the pathogenesis of OCD. PMID:28070119

Role of PTEN in the Tumor Microenvironment

DTIC Science & Technology

2008-06-01

van Diest PJ. (2008). Hexokinase III, cyclin A and galectin - 3 are overexpressed in malignant follicular thyroid nodules. Clin Endocrinol (Oxf) 2...Annual 3 . DATES COVERED (From - To) 15 May 2007 – 14 May 2008 4. TITLE AND SUBTITLE Role of PTEN in the Tumor Microenvironment 5a. CONTRACT NUMBER...1998) that impacts several signaling pathways, including phosphoinositide 3 -kinase (PI3K), and Ras-MAPK-Erk1/2 signaling pathways. Pten inactivation

Petri net siphon analysis and graph theoretic measures for identifying combination therapies in cancer.

PubMed

Behinaein, Behnam; Rudie, Karen; Sangrar, Waheed

2016-10-03

Epidermal Growth Factor Receptor (EGFR) signaling to the Ras-MAPK pathway is implicated in the development and progression of cancer and is a major focus of targeted combination therapies. Physiochemical models have been used for identifying and testing the signal-inhibiting potential of targeted therapies, however, their application to larger multi-pathway networks is limited by the availability of experimentally-determined rate and concentration parameters. An alternate strategy for identifying and evaluating drug-targetable nodes is proposed. A physiochemical model of EGFR-Ras-MAPK signaling is implemented and calibrated to experimental data. Essential topological features of the model are converted into a Petri net and nodes that behave as siphons-a structural property of Petri nets-are identified. Siphons represent potential drug-targets since they are unrecoverable if their values fall below a threshold. Centrality measures are then used to prioritize siphons identified as candidate drug-targets. Single and multiple drug-target combinations are identified which correspond to clinically relevant drug targets and exhibit inhibition synergy in physiochemical simulations of EGF-induced EGFR-Ras-MAPK signaling. Taken together, these studies suggest that siphons and centrality analyses are a promising computational strategy to identify and rank drug-targetable nodes in larger networks as they do not require knowledge of the dynamics of the system, but rely solely on topology.

IL-12 and IL-23 Production in Toxoplasma gondii- or LPS-Treated Jurkat T Cells via PI3K and MAPK Signaling Pathways.

PubMed

Ismail, Hassan Ahmed Hassan Ahmed; Kang, Byung-Hun; Kim, Jae-Su; Lee, Jae-Hyung; Choi, In-Wook; Cha, Guang-Ho; Yuk, Jae-Min; Lee, Young-Ha

2017-12-01

IL-12 and IL-23 are closely related in structure, and have been shown to play crucial roles in regulation of immune responses. However, little is known about the regulation of these cytokines in T cells. Here, we investigated the roles of PI3K and MAPK pathways in IL-12 and IL-23 production in human Jurkat T cells in response to Toxoplasma gondii and LPS. IL-12 and IL-23 production was significantly increased in T cells after stimulation with T. gondii or LPS. T. gondii and LPS increased the phosphorylation of AKT, ERK1/2, p38 MAPK, and JNK1/2 in T cells from 10 min post-stimulation, and peaked at 30-60 min. Inhibition of the PI3K pathway reduced IL-12 and IL-23 production in T. gondii-infected cells, but increased in LPS-stimulated cells. IL-12 and IL-23 production was significantly reduced by ERK1/2 and p38 MAPK inhibitors in T. gondii- and LPS-stimulated cells, but not in cells treated with a JNK1/2 inhibitor. Collectively, IL-12 and IL-23 production was positively regulated by PI3K and JNK1/2 in T. gondii-infected Jurkat cells, but negatively regulated in LPS-stimulated cells. And ERK1/2 and p38 MAPK positively regulated IL-12 and IL-23 production in Jurkat T cells. These data indicate that T. gondii and LPS induced IL-12 and IL-23 production in Jurkat T cells through the regulation of the PI3K and MAPK pathways; however, the mechanism underlying the stimulation of IL-12 and IL-23 production by T. gondii in Jurkat T cells is different from that of LPS.

Rac3 Regulates Cell Invasion, Migration and EMT in Lung Adenocarcinoma through p38 MAPK Pathway

PubMed Central

Zhang, Chenlei; Liu, Tieqin; Wang, Gebang; Wang, Huan; Che, Xiaofang; Gao, Xinghua; Liu, Hongxu

2017-01-01

Background: The role of Rac3 in cell proliferation in lung adenocarcinoma has been tackled in our previous study. However, the role of Rac3 in cell invasion and migration of lung adenocarcinoma is still not clear. Methods: The expression of Rac3 in lung adenocarcinoma specimens and paired noncancerous normal tissues were evaluated by immunohistochemistry. Lentivirus-mediated RNA interference (RNAi) was employed to silence Rac3 in lung adenocarcinoma cell lines A549 and H1299. A p38 MAPK inhibitor (LY2228820) was employed to inhibit activity of p38 MAPK pathway. Cell invasion and migration in vitro were examined by invasion and migration assays, respectively. PathScan® intracellular signaling array kit and western blot were employed in mechanism investigation. Results: Rac3 expression was frequently higher in lung adenocarcinoma than paired noncancerous normal tissues. Rac3 expression was an independent risk factor for lymphonode metastasis, and was associated with worse survival outcome. Silencing of Rac3 inhibited cell invasion and cell migration in lung adenocarcinoma cell lines. Knockdown of Rac3 decreased activity of p38 MAPK pathway. LY2228820, which was an important p38 MAPK inhibitor, inhibited Rac3-induced cell invasion and migration of lung adenocarcinoma. E-cadherin expression was increased and vimentin expression was decreased after silencing of Rac3 or following the treatment of LY2228820. Conclusions: Our findings suggest that Rac3 regulates cell invasion, migration and EMT via p38 MAPK pathway. Rac3 may be a potential biomarker of invasion and metastasis for lung adenocarcinoma, and knockdown of Rac3 may potentially serve as a promising therapeutic target for lung adenocarcinoma. PMID:28900489

INTRACELLULAR SIGNALING BY BILE ACIDS

PubMed Central

Anwer, Mohammed Sawkat

2014-01-01

Bile acids, synthesized from cholesterol, are known to produce beneficial as well as toxic effects in the liver. The beneficial effects include choleresis, immunomodulation, cell survival, while the toxic effects include cholestasis, apoptosis and cellular toxicity. It is believed that bile acids produce many of these effects by activating intracellular signaling pathways. However, it has been a challenge to relate intracellular signaling to specific and at times opposing effects of bile acids. It is becoming evident that bile acids produce different effects by activating different isoforms of phosphoinositide 3-kinase (PI3K), Protein kinase Cs (PKCs), and mitogen activated protein kinases (MAPK). Thus, the apoptotic effect of bile acids may be mediated via PI3K-110γ, while cytoprotection induce by cAMP-GEF pathway involves activation of PI3K-p110α/β isoforms. Atypical PKCζ may mediate beneficial effects and nPKCε may mediate toxic effects, while cPKCα and nPKCδ may be involved in both beneficial and toxic effects of bile acids. The opposing effects of nPKCδ activation may depend on nPKCδ phosphorylation site(s). Activation of ERK1/2 and JNK1/2 pathway appears to mediate beneficial and toxic effects, respectively, of bile acids. Activation of p38α MAPK and p38β MAPK may mediate choleretic and cholestatic effects, respectively, of bile acids. Future studies clarifying the isoform specific effects on bile formation should allow us to define potential therapeutic targets in the treatment of cholestatic disorders. PMID:25378891

JNK signaling pathway regulates sorbitol-induced Tau proteolysis and apoptosis in SH-SY5Y cells by targeting caspase-3.

PubMed

Olivera Santa-Catalina, Marta; Caballero Bermejo, Montaña; Argent, Ricardo; Alonso, Juan C; Centeno, Francisco; Lorenzo, María J

2017-12-15

Growing evidence suggests that Diabetes Mellitus increases the risk of developing Alzheimer's disease. It is well known that hyperglycemia, a key feature of Diabetes Mellitus, may induce plasma osmolarity disturbances. Both hyperglycemia and hyperosmolarity promote the altered post-translational regulation of microtubule-associated protein Tau. Interestingly, abnormal hyperphosphorylation and cleavage of Tau have been proven to lead to the genesis of filamentous structures referred to as neurofibrillary tangles, the main pathological hallmark of Alzheimer's disease. We have previously described that hyperosmotic stress induced by sorbitol promotes Tau proteolysis and apoptosis in SH-SY5Y cells via caspase-3 activation. In order to gain insights into the regulatory mechanisms of such processes, in this work we explored the intracellular signaling pathways that regulate these events. We found that sorbitol treatment significantly enhanced the activation of conventional families of MAPK in SH-SY5Y cells. Tau proteolysis was completely prevented by JNK inhibition but not affected by either ERK1/2 or p38 MAPK blockade. Moreover, inhibition of JNK, but not ERK1/2 or p38 MAPK, efficiently prevented sorbitol-induced apoptosis and caspase-3 activation. In summary, we provide evidence that JNK signaling pathway is an upstream regulator of hyperosmotic stress-induced Tau cleavage and apoptosis in SH-SY5Y through the control of caspase-3 activation. Copyright © 2017 Elsevier Inc. All rights reserved.

p38 mitogen-activated protein kinase (MAPK) first regulates filamentous actin at the 8-16-cell stage during preimplantation development.

PubMed

Paliga, Andrew J M; Natale, David R; Watson, Andrew J

2005-08-01

The MAPK (mitogen-activated protein kinase) superfamily of proteins consists of four separate signalling cascades: the c-Jun N-terminal kinase or stress-activated protein kinases (JNK/SAPK); the ERKs (extracellular-signal-regulated kinases); the ERK5 or big MAPK1; and the p38 MAPK group of protein kinases, all of which are highly conserved. To date, our studies have focused on defining the role of the p38 MAPK pathway during preimplantation development. p38 MAPK regulates actin filament formation through the downstream kinases MAPKAPK2/3 (MAPK-activated protein kinase 2/3) or MAPKAPK5 [PRAK (p38 regulated/activated kinase)] and subsequently through HSP25/27 (heat-shock protein 25/27). We recently reported that 2-cell-stage murine embryos treated with cytokine-suppressive anti-inflammatory drugs (CSAIDtrade mark; SB203580 and SB220025) display a reversible blockade of development at the 8-16-cell stage, indicating that p38 (MAPK) activity is required to complete murine preimplantation development. In the present study, we have investigated the stage-specific action and role of p38 MAPK in regulating filamentous actin during murine preimplantation development. Treatment of 8-cell-stage embryos with SB203580 and SB220025 (CSAIDtrade mark) resulted in a blockade of preimplantation development, loss of rhodamine phalloidin fluorescence, MK-p (phosphorylated MAPKAPK2/3), HSP-p (phosphorylated HSP25/27) and a redistribution of alpha-catenin immunofluorescence by 12 h of treatment. In contrast, treatment of 2- and 4-cell-stage embryos with CSAIDtrade mark drugs resulted in a loss of MK-p and HSP-p, but did not result in a loss of rhodamine phalloidin fluorescence. All these effects of p38 MAPK inhibition were reversed upon removal of the inhibitor, and development resumed in a delayed but normal manner to the blastocyst stage. Treatment of 8-cell embryos with PD098059 (ERK pathway inhibitor) did not affect development or fluorescence of MK-p, HSP-p or rhodamine phalloidin. Murine preimplantation development becomes dependent on p38 MAPK at the 8-16-cell stage, which corresponds to the stage when p38 MAPK first regulates filamentous actin during early development.

Leptin induces ADAMTS-4, ADAMTS-5, and ADAMTS-9 genes expression by mitogen-activated protein kinases and NF-ĸB signaling pathways in human chondrocytes.

PubMed

Yaykasli, Kursat Oguz; Hatipoglu, Omer Faruk; Yaykasli, Emine; Yildirim, Kubra; Kaya, Ertugrul; Ozsahin, Mustafa; Uslu, Mustafa; Gunduz, Esra

2015-01-01

Elucidation of the causes of inflammation has vital importance in the development of new approaches for the treatment of arthritic diseases. The degradation of aggrecan by upregulated disintegrin and metalloproteinase with trombospondin motifs (ADAMTSs) is the key event in the development of both rheumatoid arthritis (RA) and osteoarthritis (OA). Increased levels of leptin in both RA and OA have been demonstrated, thus linking leptin to arthritic diseases, but the mechanism has not been clarified. This study investigated the putative role of signaling pathways (p38, JNK, MEK1, NF-ĸB, and PI3) involved in leptin-induced cartilage destruction. Normal human articular chondrocytes were cultured with recombinant human leptin at 100, 250, 500, and 1000 ng/mL doses for 6, 12, 24, and 48 h, after which ADAMTS-4, -5, and -9 genes expression were determined by real time-polymerase chain reaction (RT-PCR) and Western Blot methods. The signaling pathways involved in leptin-induced ADAMTSs upregulation were also investigated by using inhibitors of signaling pathways. It was demonstrated that ADAMTSs expression level was peaked at 1000 ng/mL doses for 48 hours, and MAPKs (p38, JNK, and MEK) and NF-ĸB signaling pathways involving in leptin triggered ADAMTSs upregulation. Obesity as a risk for RA and OA may contribute to the inflammation of both RA and OA diseases by secreting adipokines like leptin. We hypothesize that leptin is involved in the development of RA and OA accompanied with obesity by increasing ADAMTS-4, -5, and -9 genes expression via MAPKs and NF-ĸB signaling pathways. © 2014 International Federation for Cell Biology.

A Conditional Knockout Mouse Model Reveals a Critical Role of PKD1 in Osteoblast Differentiation and Bone Development

PubMed Central

Li, Shao; Xu, Wanfu; Xing, Zhe; Qian, Jiabi; Chen, Liping; Gu, Ruonan; Guo, Wenjing; Lai, Xiaoju; Zhao, Wanlu; Li, Songyu; Wang, Yaodong; Wang, Q. Jane; Deng, Fan

2017-01-01

The protein kinase D family of serine/threonine kinases, particularly PKD1, has been implicated in the regulation of a complex array of fundamental biological processes. However, its function and mechanism underlying PKD1-mediated the bone development and osteoblast differentiation are not fully understood. Here we demonstrate that loss of PKD1 function led to impaired bone development and osteoblast differentiation through STAT3 and p38 MAPK signaling using in vitro and in vivo bone-specific conditional PKD1-knockout (PKD1-KO) mice models. These mice developed markedly craniofacial dysplasia, scapula dysplasia, long bone length shortage and body weight decrease compared with wild-type littermates. Moreover, deletion of PKD1 in vivo reduced trabecular development and activity of osteoblast development, confirmed by Micro-CT and histological staining as well as expression of osteoblastic marker (OPN, Runx2 and OSX). Mechanistically, loss of PKD1 mediated the downregulation of osteoblast markers and impaired osteoblast differentiation through STAT3 and p38 MAPK signaling pathways. Taken together, these results demonstrated that PKD1 contributes to the osteoblast differentiation and bone development via elevation of osteoblast markers through activation of STAT3 and p38 MAPK signaling pathways. PMID:28084409

RAS-MAPK dependence underlies a rational polytherapy strategy in EML4-ALK–positive lung cancer

PubMed Central

Hrustanovic, Gorjan; Olivas, Victor; Pazarentzos, Evangelos; Tulpule, Asmin; Asthana, Saurabh; Blakely, Collin M; Okimoto, Ross A; Lin, Luping; Neel, Dana S; Sabnis, Amit; Flanagan, Jennifer; Chan, Elton; Varella-Garcia, Marileila; Aisner, Dara L; Vaishnavi, Aria; Ou, Sai-Hong I; Collisson, Eric A; Ichihara, Eiki; Mack, Philip C; Lovly, Christine M; Karachaliou, Niki; Rosell, Rafael; Riess, Jonathan W; Doebele, Robert C; Bivona, Trever G

2016-01-01

One strategy for combating cancer-drug resistance is to deploy rational polytherapy up front that suppresses the survival and emergence of resistant tumor cells. Here we demonstrate in models of lung adenocarcinoma harboring the oncogenic fusion of ALK and EML4 that the GTPase RAS–mitogen-activated protein kinase (MAPK) pathway, but not other known ALK effectors, is required for tumor-cell survival. EML4-ALK activated RAS-MAPK signaling by engaging all three major RAS isoforms through the HELP domain of EML4. Reactivation of the MAPK pathway via either a gain in the number of copies of the gene encoding wild-type K-RAS (KRASWT) or decreased expression of the MAPK phosphatase DUSP6 promoted resistance to ALK inhibitors in vitro, and each was associated with resistance to ALK inhibitors in individuals with EML4-ALK–positive lung adenocarcinoma. Upfront inhibition of both ALK and the kinase MEK enhanced both the magnitude and duration of the initial response in preclinical models of EML4-ALK lung adenocarcinoma. Our findings identify RAS-MAPK dependence as a hallmark of EML4-ALK lung adenocarcinoma and provide a rationale for the upfront inhibition of both ALK and MEK to forestall resistance and improve patient outcomes. PMID:26301689

RAS-MAPK dependence underlies a rational polytherapy strategy in EML4-ALK-positive lung cancer.

PubMed

Hrustanovic, Gorjan; Olivas, Victor; Pazarentzos, Evangelos; Tulpule, Asmin; Asthana, Saurabh; Blakely, Collin M; Okimoto, Ross A; Lin, Luping; Neel, Dana S; Sabnis, Amit; Flanagan, Jennifer; Chan, Elton; Varella-Garcia, Marileila; Aisner, Dara L; Vaishnavi, Aria; Ou, Sai-Hong I; Collisson, Eric A; Ichihara, Eiki; Mack, Philip C; Lovly, Christine M; Karachaliou, Niki; Rosell, Rafael; Riess, Jonathan W; Doebele, Robert C; Bivona, Trever G

2015-09-01

One strategy for combating cancer-drug resistance is to deploy rational polytherapy up front that suppresses the survival and emergence of resistant tumor cells. Here we demonstrate in models of lung adenocarcinoma harboring the oncogenic fusion of ALK and EML4 that the GTPase RAS-mitogen-activated protein kinase (MAPK) pathway, but not other known ALK effectors, is required for tumor-cell survival. EML4-ALK activated RAS-MAPK signaling by engaging all three major RAS isoforms through the HELP domain of EML4. Reactivation of the MAPK pathway via either a gain in the number of copies of the gene encoding wild-type K-RAS (KRAS(WT)) or decreased expression of the MAPK phosphatase DUSP6 promoted resistance to ALK inhibitors in vitro, and each was associated with resistance to ALK inhibitors in individuals with EML4-ALK-positive lung adenocarcinoma. Upfront inhibition of both ALK and the kinase MEK enhanced both the magnitude and duration of the initial response in preclinical models of EML4-ALK lung adenocarcinoma. Our findings identify RAS-MAPK dependence as a hallmark of EML4-ALK lung adenocarcinoma and provide a rationale for the upfront inhibition of both ALK and MEK to forestall resistance and improve patient outcomes.

Effects of the brominated flame retardant tetrabromobisphenol-A (TBBPA) on cell signaling and function of Mytilus hemocytes: involvement of MAP kinases and protein kinase C.

PubMed

Canesi, Laura; Lorusso, Lucia Cecilia; Ciacci, Caterina; Betti, Michele; Gallo, Gabriella

2005-11-10

Brominated flame retardants (BFRs) are a large group of compounds added to or applied as a treatment to polymeric materials to prevent fires. Tetrabisphenol A (TBBPA) is the most important individual BFR used in industry. Although TBBPA and its derivatives can be found in environmental samples, data are very limited on the presence of this compound in biota. Research on mammals indicates that TBBPA has low toxicity in vivo; however, in vitro TBBPA can act as a cytotoxicant, neurotoxicant, immunotoxicant, thyroid hormone agonist and has a weak estrogenic activity; in particular, the effects of TBBPA have been recently ascribed to its interactions with cellular signaling pathways, in particular with mitogen activated protein kinases (MAPKs). TBBPA has high acute toxicity to aquatic organisms, such as algae, molluscs, crustaceans and fish; however, little is known on the mechanisms of action of this compound in the cells of aquatic species. In this work, we investigated the possible effects and mechanisms of action of TBBPA on the immune cells, the hemocytes, of the marine mussel Mytilus galloprovincialis. The results demonstrate that TBBPA in the low micromolar range induces hemocyte lysosomal membrane destabilization. The effect was reduced or prevented by hemocyte pre-treatment by specific inhibitors of MAPKs and of protein kinase C (PKC). TBBPA stimulated phosphorylation of MAPK members and PKC, as evaluated by electrophoresis and Western blotting with anti-phospho-antibodies, although to a different extent and with distinct time-courses. A rapid (from 5 min) and transient increase in phosphoryation of the stress-activated JNK MAPKs and of PKC was observed, followed by a later increase (at 30-60 min) in phosphorylation of extracellularly regulated MAPKs (ERK2 MAPK) and of the stress-activated p38 MAPK. TBBPA significantly stimulated the hemocyte microbicidal activity towards E. coli, lysosomal enzyme release, phagocytic activity and extracellular superoxide (O2-) production. The results demonstrate that TBBPA in vitro activates the immune function of mussel hemocytes through kinase-mediated cell signaling and that common transduction pathways are involved in mediating the effects of this BFR in mammalian and aquatic invertebrate cells.

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

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

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

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

Patient-derived iPSCs show premature neural differentiation and neuron-type specific phenotypes relevant to neurodevelopment

PubMed Central

Yeh, Erika; Dao, Dang Q.; Wu, Zhi Y.; Kandalam, Santoshi M.; Camacho, Federico M.; Tom, Curtis; Zhang, Wandong; Krencik, Robert; Rauen, Katherine A.; Ullian, Erik M.; Weiss, Lauren A.

2017-01-01

Ras/MAPK pathway signaling is a major participant in neurodevelopment, and evidence suggests that BRAF, a key Ras signal mediator, influences human behavior. We studied the role of the mutation BRAFQ257R, the most common cause of cardiofaciocutaneous syndrome (CFC), in an induced pluripotent stem cell (iPSC)-derived model of human neurodevelopment. In iPSC-derived neuronal cultures from CFC subjects, we observed decreased p-AKT and p-ERK1/2 compared to controls, as well as a depleted neural progenitor pool and rapid neuronal maturation. Pharmacological PI3K/AKT pathway manipulation recapitulated cellular phenotypes in control cells and attenuated them in CFC cells. CFC cultures displayed altered cellular subtype ratios and increased intrinsic excitability. Moreover, in CFC cells, Ras/MAPK pathway activation and morphological abnormalities exhibited cell subtype-specific differences. Our results highlight the importance of exploring specific cellular subtypes and of using iPSC models to reveal relevant human-specific neurodevelopmental events. PMID:29158583

Design and synthesis of formononetin-dithiocarbamate hybrids that inhibit growth and migration of PC-3 cells via MAPK/Wnt signaling pathways.

PubMed

Fu, Dong-Jun; Zhang, Li; Song, Jian; Mao, Ruo-Wang; Zhao, Ruo-Han; Liu, Ying-Chao; Hou, Yu-Hui; Li, Jia-Huan; Yang, Jia-Jia; Jin, Cheng-Yun; Li, Ping; Zi, Xiao-Lin; Liu, Hong-Min; Zhang, Sai-Yang; Zhang, Yan-Bing

2017-02-15

A series of novel formononetin-dithiocarbamate derivatives were designed, synthesized and evaluated for antiproliferative activity against three selected cancer cell line (MGC-803, EC-109, PC-3). The first structure-activity relationship (SAR) for this formononetin-dithiocarbamate scaffold is explored in this report with evaluation of 14 variants of the structural class. Among these analogues, tert-butyl 4-(((3-((3-(4-methoxyphenyl)-4-oxo-4H-chromen-7-yl)oxy)propyl)thio)carbonothioyl)piperazine-1-carboxylate (8i) showed the best inhibitory activity against PC-3 cells (IC 50  = 1.97 μM). Cellular mechanism studies elucidated 8i arrests cell cycle at G1 phase and regulates the expression of G1 checkpoint-related proteins in concentration-dependent manners. Furthermore, 8i could inhibit cell growth via MAPK signaling pathway and inhibit migration via Wnt pathway in PC-3 cells. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

TEC protein tyrosine kinase is involved in the Erk signaling pathway induced by HGF

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

Li, Feifei; Jiang, Yinan; Zheng, Qiping

Research highlights: {yields} TEC is rapidly tyrosine-phosphorylated and activated by HGF-stimulation in vivo or after partial hepatectomy in mice. {yields} TEC enhances the activity of Elk and serum response element (SRE) in HGF signaling pathway in hepatocyte. {yields} TEC promotes hepatocyte proliferation through the Erk-MAPK pathway. -- Abstract: Background/aims: TEC, a member of the TEC family of non-receptor type protein tyrosine kinases, has recently been suggested to play a role in hepatocyte proliferation and liver regeneration. This study aims to investigate the putative mechanisms of TEC kinase regulation of hepatocyte differentiation, i.e. to explore which signaling pathway TEC is involvedmore » in, and how TEC is activated in hepatocyte after hepatectomy and hepatocyte growth factor (HGF) stimulation. Methods: We performed immunoprecipitation (IP) and immunoblotting (IB) to examine TEC tyrosine phosphorylation after partial hepatectomy in mice and HGF stimulation in WB F-344 hepatic cells. The TEC kinase activity was determined by in vitro kinase assay. Reporter gene assay, antisense oligonucleotide and TEC dominant negative mutant (TEC{sup KM}) were used to examine the possible signaling pathways in which TEC is involved. The cell proliferation rate was evaluated by {sup 3}H-TdR incorporation. Results: TEC phosphorylation and kinase activity were increased in 1 h after hepatectomy or HGF treatment. TEC enhanced the activity of Elk and serum response element (SRE). Inhibition of MEK1 suppressed TEC phosphorylation. Blocking TEC activity dramatically decreased the activation of Erk. Reduced TEC kinase activity also suppressed the proliferation of WB F-344 cells. These results suggest TEC is involved in the Ras-MAPK pathway and acts between MEK1 and Erk. Conclusions: TEC promotes hepatocyte proliferation and regeneration and is involved in HGF-induced Erk signaling pathway.« less

Vitamin K2 Induces Mitochondria-Related Apoptosis in Human Bladder Cancer Cells via ROS and JNK/p38 MAPK Signal Pathways

PubMed Central

Duan, Fengsen; Yu, Yuejin; Guan, Rijian; Xu, Zhiliang; Liang, Huageng; Hong, Ling

2016-01-01

The effects of vitamin K2 on apoptosis in a variety of cancer cells have been well established in previous studies. However, the apoptotic effect of vitamin K2 on bladder cancer cells has not been evaluated. The aim of this study is to examine the apoptotic activity of Vitamin K2 in bladder cancer cells and investigate the underlying mechanism. In this study, Vitamin K2 induced apoptosis in bladder cancer cells through mitochondria pathway including loss of mitochondria membrane potential, cytochrome C release and caspase-3 cascade. Furthermore, the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 MAPK was detected in Vitamin K2-treated cells and both SP600125 (an inhibitor of JNK) and SB203580 (an inhibitor of p38 MAPK) completely abolished the Vitamin K2-induced apoptosis and loss of mitochondria membrane potential. Moreover, the generation of reactive oxygen species (ROS) was detected in bladder cancer cells, upon treatment of vitamin K2 and the anti-oxidant N-acetyl cysteine (NAC) almost blocked the Vitamin K2-triggered apoptosis, loss of mitochondria membrane potential and activation of JNK and p38 MAPK. Taken together, these findings revealed that Vitamin K2 induces apoptosis in bladder cancer cells via ROS-mediated JNK/p38 MAPK and Mitochondrial pathways. PMID:27570977

Vitamin K2 Induces Mitochondria-Related Apoptosis in Human Bladder Cancer Cells via ROS and JNK/p38 MAPK Signal Pathways.

PubMed

Duan, Fengsen; Yu, Yuejin; Guan, Rijian; Xu, Zhiliang; Liang, Huageng; Hong, Ling

2016-01-01

The effects of vitamin K2 on apoptosis in a variety of cancer cells have been well established in previous studies. However, the apoptotic effect of vitamin K2 on bladder cancer cells has not been evaluated. The aim of this study is to examine the apoptotic activity of Vitamin K2 in bladder cancer cells and investigate the underlying mechanism. In this study, Vitamin K2 induced apoptosis in bladder cancer cells through mitochondria pathway including loss of mitochondria membrane potential, cytochrome C release and caspase-3 cascade. Furthermore, the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 MAPK was detected in Vitamin K2-treated cells and both SP600125 (an inhibitor of JNK) and SB203580 (an inhibitor of p38 MAPK) completely abolished the Vitamin K2-induced apoptosis and loss of mitochondria membrane potential. Moreover, the generation of reactive oxygen species (ROS) was detected in bladder cancer cells, upon treatment of vitamin K2 and the anti-oxidant N-acetyl cysteine (NAC) almost blocked the Vitamin K2-triggered apoptosis, loss of mitochondria membrane potential and activation of JNK and p38 MAPK. Taken together, these findings revealed that Vitamin K2 induces apoptosis in bladder cancer cells via ROS-mediated JNK/p38 MAPK and Mitochondrial pathways.

Mitogen- and Stress-Activated Protein Kinase 1 Regulates Status Epilepticus-Evoked Cell Death in the Hippocampus

PubMed Central

Choi, Yun-Sik; Horning, Paul; Aten, Sydney; Karelina, Kate; Alzate-Correa, Diego; Arthur, J. Simon C.; Hoyt, Kari R.; Obrietan, Karl

2017-01-01

Mitogen-activated protein kinase (MAPK) signaling has been implicated in a wide range of neuronal processes, including development, plasticity, and viability. One of the principal downstream targets of both the extracellular signal-regulated kinase/MAPK pathway and the p38 MAPK pathway is Mitogen- and Stress-activated protein Kinase 1 (MSK1). Here, we sought to understand the role that MSK1 plays in neuroprotection against excitotoxic stimulation in the hippocampus. To this end, we utilized immunohistochemical labeling, a MSK1 null mouse line, cell viability assays, and array-based profiling approaches. Initially, we show that MSK1 is broadly expressed within the major neuronal cell layers of the hippocampus and that status epilepticus drives acute induction of MSK1 activation. In response to the status epilepticus paradigm, MSK1 KO mice exhibited a striking increase in vulnerability to pilocarpine-evoked cell death within the CA1 and CA3 cell layers. Further, cultured MSK1 null neurons exhibited a heighted level of N-methyl-D-aspartate-evoked excitotoxicity relative to wild-type neurons, as assessed using the lactate dehydrogenase assay. Given these findings, we examined the hippocampal transcriptional profile of MSK1 null mice. Affymetrix array profiling revealed that MSK1 deletion led to the significant (>1.25-fold) downregulation of 130 genes and an upregulation of 145 genes. Notably, functional analysis indicated that a subset of these genes contribute to neuroprotective signaling networks. Together, these data provide important new insights into the mechanism by which the MAPK/MSK1 signaling cassette confers neuroprotection against excitotoxic insults. Approaches designed to upregulate or mimic the functional effects of MSK1 may prove beneficial against an array of degenerative processes resulting from excitotoxic insults. PMID:28870089

Neuroprotective Role of a Brain-Enriched Tyrosine Phosphatase, STEP, in Focal Cerebral Ischemia

PubMed Central

Deb, Ishani; Manhas, Namratta; Poddar, Ranjana; Rajagopal, Sathyanarayanan; Allan, Andrea M.; Lombroso, Paul J.; Rosenberg, Gary A.; Candelario-Jalil, Eduardo

2013-01-01

The striatal-enriched phosphatase (STEP) is a component of the NMDA-receptor-mediated excitotoxic signaling pathway, which plays a key role in ischemic brain injury. Using neuronal cultures and a rat model of ischemic stroke, we show that STEP plays an initial role in neuroprotection, during the insult, by disrupting the p38 MAPK pathway. Degradation of active STEP during reperfusion precedes ischemic brain damage and is associated with secondary activation of p38 MAPK. Application of a cell-permeable STEP-derived peptide that is resistant to degradation and binds to p38 MAPK protects cultured neurons from hypoxia-reoxygenation injury and reduces ischemic brain damage when injected up to 6 h after the insult. Conversely, genetic deletion of STEP in mice leads to sustained p38 MAPK activation and exacerbates brain injury and neurological deficits after ischemia. Administration of the STEP-derived peptide at the onset of reperfusion not only prevents the sustained p38 MAPK activation but also reduces ischemic brain damage in STEP KO mice. The findings indicate a neuroprotective role of STEP and suggest a potential role of the STEP-derived peptide in stroke therapy. PMID:24198371

Astaxanthin inhibits NF-κB and Wnt/β-catenin signaling pathways via inactivation of Erk/MAPK and PI3K/Akt to induce intrinsic apoptosis in a hamster model of oral cancer.

PubMed

Kavitha, K; Kowshik, J; Kishore, T Kranthi Kiran; Baba, Abdul Basit; Nagini, S

2013-10-01

The oncogenic transcription factors NF-κB and β-catenin, constitutively activated by upstream serine/threonine kinases control several cellular processes implicated in malignant transformation including apoptosis evasion. The aim of this study was to investigate the chemopreventive effects of astaxanthin, an antioxidant carotenoid, in the hamster buccal pouch (HBP) carcinogenesis model based on its ability to modulate NF-κB and Wnt signaling pathways and induce apoptosis. We determined the effect of dietary supplementation of astaxanthin on the oncogenic signaling pathways - NF-κB and Wnt/β-catenin, their upstream activator kinases - Erk/MAPK and PI-3K/Akt, and the downstream event - apoptosis evasion by real-time quantitative RT-PCR, western blot, and immunohistochemical analyses. We found that astaxanthin inhibits NF-κB and Wnt signaling by downregulating the key regulatory enzymes IKKβ and GSK-3β. Analysis of gene expression and docking interactions revealed that inhibition of these pathways may be mediated via inactivation of the upstream signaling kinases Erk/Akt by astaxanthin. Astaxanthin also induced caspase-mediated mitochondrial apoptosis by downregulating the expression of antiapoptotic Bcl-2, p-Bad, and survivin and upregulating proapoptotic Bax and Bad, accompanied by efflux of Smac/Diablo and cytochrome-c into the cytosol, and induced cleavage of poly (ADP-ribose) polymerase (PARP). The results provide compelling evidence that astaxanthin exerts chemopreventive effects by concurrently inhibiting phosphorylation of transcription factors and signaling kinases and inducing intrinsic apoptosis. Astaxanthin targets key molecules in oncogenic signaling pathways and induces apoptosis and is a promising candidate agent for cancer prevention and therapy. Copyright © 2013 Elsevier B.V. All rights reserved.

Schisantherin A suppresses osteoclast formation and wear particle-induced osteolysis via modulating RANKL signaling pathways

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

He, Yi; Zhang, Qing; Shen, Yi

Highlights: • Schisantherin A suppresses osteoclasts formation and function in vitro. • Schisantherin A impairs RANKL signaling pathway. • Schisantherin A suppresses osteolysis in vivo. • Schisantherin A may be used for treating osteoclast related diseases. - Abstract: Receptor activator of NF-κB ligand (RANKL) plays critical role in osteoclastogenesis. Targeting RANKL signaling pathways has been a promising strategy for treating osteoclast related bone diseases such as osteoporosis and aseptic prosthetic loosening. Schisantherin A (SA), a dibenzocyclooctadiene lignan isolated from the fruit of Schisandra sphenanthera, has been used as an antitussive, tonic, and sedative agent, but its effect on osteoclasts hasmore » been hitherto unknown. In the present study, SA was found to inhibit RANKL-induced osteoclast formation and bone resorption. The osteoclastic specific marker genes induced by RANKL including c-Src, SA inhibited OSCAR, cathepsin K and TRAP in a dose dependent manner. Further signal transduction studies revealed that SA down-regulate RANKL-induced nuclear factor-kappaB (NF-κB) signaling activation by suppressing the phosphorylation and degradation of IκBα, and subsequently preventing the NF-κB transcriptional activity. Moreover, SA also decreased the RANKL-induced MAPKs signaling pathway, including JNK and ERK1/2 posphorylation while had no obvious effects on p38 activation. Finally, SA suppressed the NF-κB and MAPKs subsequent gene expression of NFATc1 and c-Fos. In vivo studies, SA inhibited osteoclast function and exhibited bone protection effect in wear-particle-induced bone erosion model. Taken together, SA could attenuate osteoclast formation and wear particle-induced osteolysis by mediating RANKL signaling pathways. These data indicated that SA is a promising therapeutic natural compound for the treatment of osteoclast-related prosthesis loosening.« less

[MAPK signaling pathways involved in aluminum-induced apoptosis and necroptosis in SH-SY5Y cells].

PubMed

Jia, Xiaofang; Zhang, Qinli; Niu, Qiao

2014-11-01

To explore the role of MAPK signaling pathway in apoptosis and necroptosis induced by aluminum in SH-SY5Y cells. To imitate neural cell death induced by aluminium, AlCl3 x 6H2O (4 mmol/L) was used to treat SH-SY5Y cells. Necrostatin-1 (Nec-1,60 μmol/L), the specific inhibitor for necroptosis, and zVAD-fmk (20 μmol/L), the specific inhibitor for apoptosis, were added into cultures for inhibiting the occurrence of necroptosis and apoptosis. CCK-8 was performed to measure cell viability, flow cytometry was used to test the difference of apoptosis rate and necrosis rate between groups, and western-blot was used to detect the change of MAPK protein. Compared with blank control group, solvent control group, Nec-1 control group and zVAD-fmk control group, cell viabiligy of Al(3+) exposed group, Al(3+) plus Nec-1 group and Al(3+) plus zVAD-fmk group decreaced (P < 0.05). Compared with Al(3+) exposed group, cell viability of Al(3+) plus Nec-1 group and Al(3+) plus zVAD-fmk group increased (P < 0.05). Necrotic rate and apoptotic rate in Al(3+) exposed group, Al(3+) plus Nec-1 group and Al(3+) plus zVAD-fmk group obviously increased compared with blank control group, solvent control group, Nec-1 control group and zVAD-fmk control group (P < 0.05). Compared with Al(3+) exposed group, necrotic and apaptotic rate of Al(3+) plus zVAD-fmk group and Al(3+) plus Nec-1 group were statistically significant decreased (P < 0.05). Compared with blank control group, solvent control group, Nec-1 control group and zVAD-fmk control group, expression of p-p38 in Al(3+) exposed group, Al(3+) plus Nec-1 group and Al(3+) plus zVAD-fmk group increased obviously (P < 0.05), and expression of p-ERK decreased significantly (P < 0.05). Compared with Al(3+) exposed group, expression of p-p38 decreased (P < 0.05), but p-ERK increased in Al(3+) plus Nec-1 group (P < 0.05). The ERK and p38 MAPK signaling pathways are involved in aluminum-induced necroptosis in SH-SY5Y cells, but only ERK signaling pathway is involved in aluminum-induced apoptosis, and JNK signaling pathway is not involved in aluminum-induced cell death.

Regulation of Facilitative Glucose Transporters and AKT/MAPK/PRKAA Signaling via Estradiol and Progesterone in the Mouse Uterine Epithelium1

PubMed Central

Kim, Sung Tae; Moley, Kelle H.

2009-01-01

Adequate uterine glucose metabolism is an essential part of embryo implantation and the development of an adequate utero-fetal environment. However, expression of facilitative glucose transporters (GLUTs [solute transporter family SLC2A]) and AKT/MAPK/PRKAA (PRKAA) signaling has not been described in the mouse uterine cells, to our knowledge. The objective of this study was to determine the hormonal regulation of SLC2A protein expression and AKT/MAPK/PRKAA signaling in the mouse uterine epithelial cells during estrous cycles and peri-implantation periods. SLC2As 1, 4, 8, and 9B were highly expressed in the luminal and glandular epithelia of estrous stage. In metestrous and diestrous stages, expression of SLC2As 1, 4, 8, and 9B was lower than that in proestrous stage. Levels of activated phospho-AKT (p-AKT), p-MAPK3, and p-MAPK1 also varied during the estrous cycle. Estrogen and progesterone injection in an ovariectomized mouse (delayed implantation model) resulted in a decrease and an increase, respectively, in expression of GLUTs in the luminal epithelial cells of the uterus. The expression of SLC2A1, SLC2A8, SLC2A9B, p-AKT, p-MAPK3/1, and p-PRKAA was increased in the decidual region of the implantation sites and was significantly increased in the uterus of activated implantation. Using an artificial decidualization mouse model, it was also demonstrated that expression of the same GLUTs, p-MAPK3/1, and p-PRKAA was dramatically higher in the decidualized uteri than that in the control uteri. These results suggest that steroid hormones regulate expression of uterine epithelial GLUTs possibly through AKT/MAPK/PRKAA signaling pathways and that glucose utilization may have an important role in decidualization and possibly in the maintenance of pregnancy. PMID:19208550

Inhibition of curcumin on influenza A virus infection and influenzal pneumonia via oxidative stress, TLR2/4, p38/JNK MAPK and NF-κB pathways.

PubMed

Dai, Jianping; Gu, Liming; Su, Yun; Wang, Qianwen; Zhao, Ying; Chen, Xiaoxua; Deng, Huixiong; Li, Weizhong; Wang, Gefei; Li, Kangsheng

2018-01-01

Oxidative stress, Nrf2-HO-1 and TLR-MAPK/NF-κB signaling pathways have been proved to be involved in influenza A virus (IAV) replication and influenzal pneumonia. In the previous studies, we have performed several high-throughput drug screenings based on the TLR pathways. In the present study, through plaque inhibition test, luciferase reporter assay, TCID 50 , qRT-PCR, western blotting, ELISA and siRNA assays, we investigated the effect and mechanism of action of curcumin against IAV infection in vitro and in vivo. The results showed that curcumin could directly inactivate IAV, blocked IAV adsorption and inhibited IAV proliferation. As for the underlying mechanisms, we found that curcumin could significantly inhibit IAV-induced oxidative stress, increased Nrf2, HO-1, NQO1, GSTA3 and IFN-β production, and suppressed IAV-induced activation of TLR2/4/7, Akt, p38/JNK MAPK and NF-κB pathways. Suppression of Nrf2 via siRNA significantly abolished the stimulatory effect of curcumin on HO-1, NQO1, GSTA3 and IFN-β production and meanwhile blocked the inhibitory effect of curcumin on IAV M2 production. Oxidant H 2 O 2 and TLR2/4, p38/JNK and NF-κB agonists could significantly antagonize the anti-IAV activity of curcumin in vitro. Additionally, curcumin significantly increased the survival rate of mice, reduced lung index, inflammatory cytokines and lung IAV titer, and finally improved pulmonary histopathological changes after IAV infection. In conclusion, curcumin can directly inactivate IAV, inhibits IAV adsorption and replication; and its inhibition on IAV replication may be via activating Nrf2 signal and inhibiting IAV-induced activation of TLR2/4, p38/JNK MAPK and NF-κB pathways. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of Phosphatidylinositol-3 Kinase Pathway in NMDA Preconditioning: Different Mechanisms for Seizures and Hippocampal Neuronal Degeneration Induced by Quinolinic Acid.

PubMed

Constantino, Leandra C; Binder, Luisa B; Vandresen-Filho, Samuel; Viola, Giordano G; Ludka, Fabiana K; Lopes, Mark W; Leal, Rodrigo B; Tasca, Carla I

2018-04-20

N-methyl D-aspartate (NMDA) preconditioning is evoked by the administration of a subtoxic dose of NMDA and is protective against neuronal excitotoxicity. This effect may involve a diversity of targets and cell signaling cascades associated to neuroprotection. Phosphatidylinositol-3 kinase/protein kinase B (PI3K/Akt) and mitogen-activated protein kinases (MAPKs) such as extracellular regulated protein kinase 1/2 (ERK1/2) and p38 MAPK pathways play a major role in neuroprotective mechanisms. However, their involvement in NMDA preconditioning was not yet fully investigated. The present study aimed to evaluate the effect of NMDA preconditioning on PI3K/Akt, ERK1/2, and p38 MAPK pathways in the hippocampus of mice and characterize the involvement of PI3K on NMDA preconditioning-evoked prevention of seizures and hippocampal cell damage induced by quinolinic acid (QA). Thus, mice received wortmannin (a PI3K inhibitor) and 15 min later a subconvulsant dose of NMDA (preconditioning) or saline. After 24 h of this treatment, an intracerebroventricular QA infusion was administered. Phosphorylation levels and total content of Akt, glycogen synthase protein kinase-3β (GSK-3β), ERK1/2, and p38 MAPK were not altered after 24 h of NMDA preconditioning with or without wortmmanin pretreatment. Moreover, after QA administration, behavioral seizures, hippocampal neuronal degeneration, and Akt activation were evaluated. Inhibition of PI3K pathway was effective in abolishing the protective effect of NMDA preconditioning against QA-induced seizures, but did not modify neuronal protection promoted by preconditioning as evaluated by Fluoro-Jade B staining. The study confirms that PI3K participates in the mechanism of protection induced by NMDA preconditioning against QA-induced seizures. Conversely, NMDA preconditioning-evoked protection against neuronal degeneration is not altered by PI3K signaling pathway inhibition. These results point to differential mechanisms regarding protection against a behavioral and cellular manifestation of neural damage.

Low-Dose Radiation Induces Cell Proliferation in Human Embryonic Lung Fibroblasts but not in Lung Cancer Cells

PubMed Central

Liang, Xinyue; Gu, Junlian; Yu, Dehai; Wang, Guanjun; Zhou, Lei; Zhang, Xiaoying; Zhao, Yuguang; Chen, Xiao; Zheng, Shirong; Liu, Qiang; Cai, Lu

2016-01-01

Hormesis and adaptive responses are 2 important biological effects of low-dose ionizing radiation (LDR). In normal tissue, LDR induces hormesis as evinced by increased cell proliferation; however, whether LDR also increases tumor cell proliferation needs to be investigated. In this study, cell proliferation was assayed by total cell numbers and the Cell Counting Kit 8 assay. Mitogen-activated protein kinases (MAPK)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3′ -kinase(PI3K)-Akt (PI3K/AKT) phosphorylation were determined by Western blot analysis. Human embryonic lung fibroblast 2BS and lung cancer NCI-H446 cell lines were irradiated with LDR at different doses (20-100 mGy). In response to 20 to 75 mGy X-rays, cell proliferation was significantly increased in 2BS but not in NCI-H446 cells. In 2BS cells, LDR at 20 to 75 mGy also stimulated phosphorylation of MAPK/ERK pathway proteins including ERK, MEK, and Raf and of the PI3K/AKT pathway protein AKT. To test whether ERK1/2 and AKT pathway activation was involved in the stimulation of cell proliferation in 2BS cells, the MAPK/ERK and PI3K/AKT pathways were inhibited using their specific inhibitors, U0126 and LY294002. U0126 decreased the phosphorylation of ERK1/2, and LY294002 decreased the phosphorylation of AKT; each could significantly inhibit LDR-induced 2BS cell proliferation. However, LDR did not stimulate these kinases, and kinase inhibitors also did not affect cell proliferation in the NCI-H446 cells. These results suggest that LDR stimulates cell proliferation via the activation of both MAPK/ERK and PI3K/AKT signaling pathways in 2BS but not in NCI-H446 cells. This finding implies the potential for applying LDR to protect normal tissues from radiotherapy without diminishing the efficacy of tumor therapy. PMID:26788032

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

PubMed

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

2014-03-01

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

S-Nitrosylation of Ras Mediates Nitric Oxide-Dependent Post-Injury Neurogenesis in a Seizure Model.

PubMed

Santos, Ana Isabel; Carreira, Bruno Pereira; Izquierdo-Álvarez, Alicia; Ramos, Elena; Lourenço, Ana Sofia; Filipa Santos, Daniela; Morte, Maria Inês; Ribeiro, Luís Filipe; Marreiros, Ana; Sánchez-López, Nuria; Marina, Anabel; Carvalho, Caetana Monteiro; Martínez-Ruiz, Antonio; Araújo, Inês Maria

2018-01-01

Nitric oxide (NO) is involved in the upregulation of endogenous neurogenesis in the subventricular zone and in the hippocampus after injury. One of the main neurogenic pathways activated by NO is the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) pathway, downstream of the epidermal growth factor receptor. However, the mechanism by which NO stimulates cell proliferation through activation of the ERK/MAPK pathway remains unknown, although p21Ras seems to be one of the earliest targets of NO. Here, we aimed at studying the possible neurogenic action of NO by post-translational modification of p21Ras as a relevant target for early neurogenic events promoted by NO in neural stem cells (NSCs). We show that NO caused S-nitrosylation (SNO) of p21Ras in Cys118, which triggered downstream activation of the ERK/MAPK pathway and proliferation of NSC. Moreover, in cells overexpressing a mutant Ras in which Cys118 was replaced by a serine-C118S-, cells were insensitive to NO, and no increase in SNO, in ERK phosphorylation, or in cell proliferation was observed. We also show that, after seizures, in the presence of NO derived from inducible nitric oxide synthase, there was an increase in p21Ras cysteine modification that was concomitant with the previously described stimulation of proliferation in the dentate gyrus. Our work identifies p21Ras and its SNO as an early target of NO during signaling events that lead to NSC proliferation and neurogenesis. Our data highlight Ras SNO as an early event leading to NSC proliferation, and they may provide a target for NO-induced stimulation of neurogenesis with implications for brain repair. Antioxid. Redox Signal. 28, 15-30.

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

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.

Synaptically Driven Phosphorylation of Ribosomal Protein S6 Is Differentially Regulated at Active Synapses versus Dendrites and Cell Bodies by MAPK and PI3K/mTOR Signaling Pathways

ERIC Educational Resources Information Center

Pirbhoy, Patricia Salgado; Farris, Shannon; Steward, Oswald

2017-01-01

High-frequency stimulation of the medial perforant path triggers robust phosphorylation of ribosomal protein S6 (rpS6) in activated dendritic domains and granule cell bodies. Here we dissect the signaling pathways responsible for synaptically driven rpS6 phosphorylation in the dentate gyrus using pharmacological agents to inhibit PI3-kinase/mTOR…

Ras mutation cooperates with β-catenin activation to drive bladder tumourigenesis.

PubMed

Ahmad, I; Patel, R; Liu, Y; Singh, L B; Taketo, M M; Wu, X-R; Leung, H Y; Sansom, O J

2011-03-03

Mutations in the Ras family of proteins (predominantly in H-Ras) occur in approximately 40% of urothelial cell carcinoma (UCC). However, relatively little is known about subsequent mutations/pathway alterations that allow tumour progression. Indeed, expressing mutant H-Ras within the mouse bladder does not lead to tumour formation, unless this is expressed at high levels. The Wnt signalling pathway is deregulated in approximately 25% of UCC, so we examined if this correlated with the activation of MAPK signalling in human UCC and found a significant correlation. To test the functional significance of this association we examined the impact of combining Ras mutation (H-Ras(Q61L) or K-Ras(G12D)) with an activating β-catenin mutation within the mouse bladder using Cre-LoxP technology. Although alone, neither Ras mutation nor β-catenin activation led to UCC (within 12 months), mice carrying both mutations rapidly developed UCC. Mechanistically this was associated with reduced levels of p21 with dependence on the MAPK signalling pathway. Moreover, tumours from these mice were sensitive to MEK inhibition. Importantly, in human UCC there was a negative correlation between levels of p-ERK and p21 suggesting that p21 accumulation may block tumour progression following Ras mutation. Taken together these data definitively show Ras pathway activation strongly cooperates with Wnt signalling to drive UCC in vivo.

17betaE2 promotes cell proliferation in endometriosis by decreasing PTEN via NFkappaB-dependent pathway.

PubMed

Zhang, Hui; Zhao, Xingbo; Liu, Shu; Li, Jijun; Wen, Zeqing; Li, Mingjiang

2010-04-12

The objective of this study was to explore the mechanism of phosphatase and tensin homolog (PTEN) loss in endometriosis. We found that aberrant PTEN expression and mitogen-activated protein kinases (MAPK)/ERK, phosphoinositide 3-kinase (PI3K)/AKt, and nuclear factor-kappaB (NFkappaB) signaling overactivities coexisted in endometriosis. In vitro, 17beta-estradiol rapidly activated the 3 pathways in endometriotic cells and specific inhibitions on the 3 pathways respectively blocked 17beta-estradiol-induced cell proliferation. 17beta-estradiol suppressed PTEN transcription and expression in endometriotic cells which was abolished by specific NFkappaB inhibition. Total/nuclear PTEN-loss and MAPK/ERK, PI3K/AKt, and NFkappaB signal overactivities coexist in endometriosis. In vitro, 17beta-estradiol can promotes cell proliferation in endometriosis by activating PI3K/AKt pathway via an NFkappaB/PTEN-dependent pathway. For the first time we propose the possibility of the presence of a positive feedback-loop: 17beta-estradiol-->high NFkappaB-->low PTEN-->high PI3K-->high NFkappaB, in endometriosis, which may finally promote the proliferation of ectopic endometrial epithelial cells and in turn contributes to the progression of the disease.

Genetic responses to seasonal variation in altitudinal stress: whole-genome resequencing of great tit in eastern Himalayas

PubMed Central

Qu, Yanhua; Tian, Shilin; Han, Naijian; Zhao, Hongwei; Gao, Bin; Fu, Jun; Cheng, Yalin; Song, Gang; Ericson, Per G. P.; Zhang, Yong E.; Wang, Dawei; Quan, Qing; Jiang, Zhi; Li, Ruiqiang; Lei, Fumin

2015-01-01

Species that undertake altitudinal migrations are exposed to a considerable seasonal variation in oxygen levels and temperature. How they cope with this was studied in a population of great tit (Parus major) that breeds at high elevations and winters at lower elevations in the eastern Himalayas. Comparison of population genomics of high altitudinal great tits and those living in lowlands revealed an accelerated genetic selection for carbohydrate energy metabolism (amino sugar, nucleotide sugar metabolism and insulin signaling pathways) and hypoxia response (PI3K-akt, mTOR and MAPK signaling pathways) in the high altitudinal population. The PI3K-akt, mTOR and MAPK pathways modulate the hypoxia-inducible factors, HIF-1α and VEGF protein expression thus indirectly regulate hypoxia induced angiogenesis, erythropoiesis and vasodilatation. The strategies observed in high altitudinal great tits differ from those described in a closely related species on the Tibetan Plateau, the sedentary ground tit (Parus humilis). This species has enhanced selection in lipid-specific metabolic pathways and hypoxia-inducible factor pathway (HIF-1). Comparative population genomics also revealed selection for larger body size in high altitudinal great tits. PMID:26404527

A Putative Mechanism of Age-Related Synaptic Dysfunction Based on the Impact of IGF-1 Receptor Signaling on Synaptic CaMKIIα Phosphorylation.

PubMed

Ogundele, Olalekan M; Pardo, Joaquin; Francis, Joseph; Goya, Rodolfo G; Lee, Charles C

2018-01-01

Insulin-like growth factor 1 receptor (IGF-1R) signaling regulates the activity and phosphorylation of downstream kinases linked to inflammation, neurodevelopment, aging and synaptic function. In addition to the control of Ca 2+ currents, IGF-1R signaling modulates the activity of calcium-calmodulin-dependent kinase 2 alpha (CaMKIIα) and mitogen activated protein kinase (MAPK/ErK) through multiple signaling pathways. These proteins (CaMKIIα and MAPK) regulate Ca 2+ movement and long-term potentiation (LTP). Since IGF-1R controls the synaptic activity of Ca 2+ , CaMKIIα and MAPK signaling, the possible mechanism through which an age-dependent change in IGF-1R can alter the synaptic expression and phosphorylation of these proteins in aging needs to be investigated. In this study, we evaluated the relationship between an age-dependent change in brain IGF-1R and phosphorylation of CaMKIIα/MAPK. Furthermore, we elucidated possible mechanisms through which dysregulated CaMKIIα/MAPK interaction may be linked to a change in neurotransmitter processing and synaptic function. Male C57BL/6 VGAT-Venus mice at postnatal days 80 (P80), 365 and 730 were used to study age-related neural changes in two brain regions associated with cognitive function: hippocampus and prefrontal cortex (PFC). By means of high throughput confocal imaging and quantitative immunoblotting, we evaluated the distribution and expression of IGF-1, IGF-1R, CaMKIIα, p-CaMKIIα, MAPK and p-MAPK in whole brain lysate, hippocampus and cortex. Furthermore, we compared protein expression patterns and regional changes at P80, P365 and P730. Ultimately, we determined the relative phosphorylation pattern of CaMKIIα and MAPK through quantification of neural p-CaMKIIα and p-MAPK/ErK, and IGF-1R expression for P80, P365 and P730 brain samples. In addition to a change in synaptic function, our results show a decrease in neural IGF-1/IGF-1R expression in whole brain, hippocampus and cortex of aged mice. This was associated with a significant upregulation of phosphorylated neural MAPK (p-MAPK) and decrease in total brain CaMKIIα (i.e., CaMKIIα and p-CaMKIIα) in the aged brain. Taken together, we showed that brain aging is associated with a change in neural IGF-1/IGF-1R expression and may be linked to a change in phosphorylation of synaptic kinases (CaMKIIα and MAPK) that are involved in the modulation of LTP.

Mitogen-activated protein kinase signaling in the heart: angels versus demons in a heart-breaking tale.

PubMed

Rose, Beth A; Force, Thomas; Wang, Yibin

2010-10-01

Among the myriad of intracellular signaling networks that govern the cardiac development and pathogenesis, mitogen-activated protein kinases (MAPKs) are prominent players that have been the focus of extensive investigations in the past decades. The four best characterized MAPK subfamilies, ERK1/2, JNK, p38, and ERK5, are the targets of pharmacological and genetic manipulations to uncover their roles in cardiac development, function, and diseases. However, information reported in the literature from these efforts has not yet resulted in a clear view about the roles of specific MAPK pathways in heart. Rather, controversies from contradictive results have led to a perception that MAPKs are ambiguous characters in heart with both protective and detrimental effects. The primary object of this review is to provide a comprehensive overview of the current progress, in an effort to highlight the areas where consensus is established verses the ones where controversy remains. MAPKs in cardiac development, cardiac hypertrophy, ischemia/reperfusion injury, and pathological remodeling are the main focuses of this review as these represent the most critical issues for evaluating MAPKs as viable targets of therapeutic development. The studies presented in this review will help to reveal the major challenges in the field and the limitations of current approaches and point to a critical need in future studies to gain better understanding of the fundamental mechanisms of MAPK function and regulation in the heart.

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

PubMed Central

Roux, Philippe P.; Blenis, John

2004-01-01

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

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

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

Dziembowska, Magdalena; Danilkiewicz, Malgorzata; Wesolowska, Aleksandra

2007-03-23

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

Dusp6 attenuates Ras/MAPK signaling to limit zebrafish heart regeneration.

PubMed

Missinato, Maria A; Saydmohammed, Manush; Zuppo, Daniel A; Rao, Krithika S; Opie, Graham W; Kühn, Bernhard; Tsang, Michael

2018-03-06

Zebrafish regenerate cardiac tissue through proliferation of pre-existing cardiomyocytes and neovascularization. Secreted growth factors such as FGFs, IGF, PDGFs and Neuregulin play essential roles in stimulating cardiomyocyte proliferation. These factors activate the Ras/MAPK pathway, which is tightly controlled by the feedback attenuator Dual specificity phosphatase 6 (Dusp6), an ERK phosphatase. Here, we show that suppressing Dusp6 function enhances cardiac regeneration. Inactivation of Dusp6 by small molecules or by gene inactivation increased cardiomyocyte proliferation, coronary angiogenesis, and reduced fibrosis after ventricular resection. Inhibition of Erbb or PDGF receptor signaling suppressed cardiac regeneration in wild-type zebrafish, but had a milder effect on regeneration in dusp6 mutants. Moreover, in rat primary cardiomyocytes, NRG1-stimulated proliferation can be enhanced upon chemical inhibition of Dusp6 with BCI. Our results suggest that Dusp6 attenuates Ras/MAPK signaling during regeneration and that suppressing Dusp6 can enhance cardiac repair. © 2018. Published by The Company of Biologists Ltd.

Comparative study of the efficacy of pulsed electromagnetic field and low level laser therapy on mitogen-activated protein kinases.

PubMed

El-Makakey, Ayman M; El-Sharaby, Radwa M; Hassan, Mohammed H; Balbaa, Alaa

2017-03-01

Mitogen-Activated Protein Kinases (MAPKs) consist of three major signaling members: extracellular signal-regulated kinase (ERK), p38 and C-JUN N-terminal kinase (JNK). We investigated physiological effects of Pulsed Electromagnetic Field Therapy (PEMFT) and Low Level Laser Therapy (LLLT) on human body, adopting the expression level of mitogen-activated protein kinases as an indicator via assessment of the activation levels of three major families of MAPKS, ERK, p38 and JNK in the peripheral lymphocytes of patients before and after the therapies. Assessment for the expression levels of MAPKs families' were done, in the peripheral lymphocytes of patients recently have appendectomy, using flow cytometric analysis of multiple signaling pathways, pre and post LLLT and PEMFT application (twice daily for 6 successive days) on the appendectomy wound. There were non-significant differences in the expression levels of MAPKs families' pre- therapies application. But there were significant increase in the ERK expression levels post application of LLLT compared to its pre application (p<0.01). Also, there was significant increase in the ERK, p38 and C-Jun N terminal expression level values post application of PEMFT compared to its pre application expression levels (p<0.01 for each). The present study demonstrates that PEMFT has a powerful healing effect more than LLLT as it increase the activation of ERK, P38 and C-Jun-N Terminal while LLLT only increase the activation of ERK. LLLT has more potent pain decreasing effect than PEMFT as it does not activate P38 pathway like PEMFT.

Myricetin Protects Cells against Oxidative Stress-Induced Apoptosis via Regulation of PI3K/Akt and MAPK Signaling Pathways

PubMed Central

Kang, Kyoung Ah; Wang, Zhi Hong; Zhang, Rui; Piao, Mei Jing; Kim, Ki Cheon; Kang, Sam Sik; Kim, Young Woo; Lee, Jongsung; Park, Deokhoon; Hyun, Jin Won

2010-01-01

Recently, we demonstrated that myricetin exhibits cytoprotective effects against H2O2-induced cell damage via its antioxidant properties. In the present study, myricetin was found to inhibit H2O2-induced apoptosis in Chinese hamster lung fibroblast (V79-4) cells, as shown by decreased apoptotic bodies, nuclear fragmentation, sub-G1 cell population, and disruption of mitochondrial membrane potential (Δψm), which are increased in H2O2-treated cells. Western blot data showed that in H2O2-treated cells, myricetin increased the level of Bcl-2, which is an anti-apoptotic factor, and decreased the levels of Bax, active caspase-9 and -3, which are pro-apoptotic factors. And myricetin inhibited release of cytochrome c from mitochondria to cytosol in H2O2-treated cells. Myricetin-induced survival correlated with Akt activity, and the rescue of cells by myricetin treatment against H2O2-induced apoptosis was inhibited by the specific PI3K (phosphoinositol-3-kinase) inhibitor. Myricetin-mediated survival also inhibited the activation of p38 mitogen activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK), which are members of MAPK. Our studies suggest that myricetin prevents oxidative stress-induced apoptosis via regulation of PI3K/Akt and MAPK signaling pathways. PMID:21151442

Lasiodin inhibits proliferation of human nasopharyngeal carcinoma cells by simultaneous modulation of the Apaf-1/caspase, AKT/MAPK and COX-2/NF-κB signaling pathways.

PubMed

Lin, Lianzhu; Deng, Wuguo; Tian, Yun; Chen, Wangbing; Wang, Jingshu; Fu, Lingyi; Shi, Dingbo; Zhao, Mouming; Luo, Wei

2014-01-01

Rabdosia serra has been widely used for the treatment of the various human diseases. However, the antiproliferative effects and underlying mechanisms of the compounds in this herb remain largely unknown. In this study, an antiproliferative compound against human nasopharyngeal carcinoma (NPC) cells from Rabdosia serra was purified and identified as lasiodin (a diterpenoid). The treatment with lasiodin inhibited cell viability and migration. Lasiodin also mediated the cell morphology change and induced apoptosis in NPC cells. The treatment with lasiodin induced the Apaf-1 expression, triggered the cytochrome-C release, and stimulated the PARP, caspase-3 and caspase-9 cleavages, thereby activating the apoptotic pathways. The treatment with lasiodin also significantly inhibited the phosphorylations of the AKT, ERK1/2, p38 and JNK proteins. The pretreatment with the AKT or MAPK-selective inhibitors considerably blocked the lasiodin-mediated inhibition of cell proliferation. Moreover, the treatment with lasiodin inhibited the COX-2 expression, abrogated NF-κB binding to the COX-2 promoter, and promoted the NF-κB translocation from cell nuclei to cytosol. The pretreatment with a COX-2-selective inhibitor abrogated the lasiodin-induced inhibition of cell proliferation. These results indicated that lasiodin simultaneously activated the Apaf-1/caspase-dependent apoptotic pathways and suppressed the AKT/MAPK and COX-2/NF-κB signaling pathways. This study also suggested that lasiodin could be a promising natural compound for the prevention and treatment of NPC.

Toxic metabolites, MAPK and Nrf2/Keap1 signaling pathways involved in oxidative toxicity in mice liver after chronic exposure to Mequindox.

PubMed

Liu, Qianying; Lei, Zhixin; Huang, Anxiong; Wu, Qinghua; Xie, Shuyu; Awais, Ihsan; Dai, Menghong; Wang, Xu; Yuan, Zonghui

2017-02-03

Mequindox (MEQ) is a synthetic antimicrobial agent of quinoxaline-1,4-dioxide group (QdNOs). The liver is regarded as the toxicity target of QdNOs, and the role of N → O group-associated various toxicities mediated by QdNOs is well recognized. However, the mechanism underlying the in vivo effects of MEQ on the liver, and whether the metabolic pathway of MEQ is altered in response to the pathophysiological conditions still remain unclear. We now provide evidence that MEQ triggers oxidative damage in the liver. Moreover, using LC/MS-ITTOF analysis, two metabolites of MEQ were detected in the liver, which directly confirms the potential connection between N → O group reduction metabolism of MEQ and liver toxicity. The gender difference in MEQ-induced oxidative stress might be due to adrenal toxicity and the generation of M4 (2-isoethanol 1-desoxymequindox). Furthermore, up-regulation of the MAPK and Nrf2-Keap1 family and phase II detoxifying enzymes (HO-1, GCLC and NQO1) were also observed. The present study demonstrated for the first time the protein peroxidation and a proposal metabolic pathway after chronic exposure of MEQ, and illustrated that the MAPK, Nrf2-Keap1 and NF-кB signaling pathways, as well as the altered metabolism of MEQ, were involved in oxidative toxicity mediated by MEQ in vivo.

Toxic metabolites, MAPK and Nrf2/Keap1 signaling pathways involved in oxidative toxicity in mice liver after chronic exposure to Mequindox

PubMed Central

Liu, Qianying; Lei, Zhixin; Huang, Anxiong; Wu, Qinghua; Xie, Shuyu; Awais, Ihsan; Dai, Menghong; Wang, Xu; Yuan, Zonghui

2017-01-01

Mequindox (MEQ) is a synthetic antimicrobial agent of quinoxaline-1,4-dioxide group (QdNOs). The liver is regarded as the toxicity target of QdNOs, and the role of N → O group-associated various toxicities mediated by QdNOs is well recognized. However, the mechanism underlying the in vivo effects of MEQ on the liver, and whether the metabolic pathway of MEQ is altered in response to the pathophysiological conditions still remain unclear. We now provide evidence that MEQ triggers oxidative damage in the liver. Moreover, using LC/MS-ITTOF analysis, two metabolites of MEQ were detected in the liver, which directly confirms the potential connection between N → O group reduction metabolism of MEQ and liver toxicity. The gender difference in MEQ-induced oxidative stress might be due to adrenal toxicity and the generation of M4 (2-isoethanol 1-desoxymequindox). Furthermore, up-regulation of the MAPK and Nrf2-Keap1 family and phase II detoxifying enzymes (HO-1, GCLC and NQO1) were also observed. The present study demonstrated for the first time the protein peroxidation and a proposal metabolic pathway after chronic exposure of MEQ, and illustrated that the MAPK, Nrf2-Keap1 and NF-кB signaling pathways, as well as the altered metabolism of MEQ, were involved in oxidative toxicity mediated by MEQ in vivo. PMID:28157180

Control of adipogenesis by the autocrine interplays between angiotensin 1-7/Mas receptor and angiotensin II/AT1 receptor signaling pathways.

PubMed

Than, Aung; Leow, Melvin Khee-Shing; Chen, Peng

2013-05-31

Angiotensin II (AngII), a peptide hormone released by adipocytes, can be catabolized by adipose angiotensin-converting enzyme 2 (ACE2) to form Ang(1-7). Co-expression of AngII receptors (AT1 and AT2) and Ang(1-7) receptors (Mas) in adipocytes implies the autocrine regulation of the local angiotensin system upon adipocyte functions, through yet unknown interactive mechanisms. In the present study, we reveal the adipogenic effects of Ang(1-7) through activation of Mas receptor and its subtle interplays with the antiadipogenic AngII-AT1 signaling pathways. Specifically, in human and 3T3-L1 preadipocytes, Ang(1-7)-Mas signaling promotes adipogenesis via activation of PI3K/Akt and inhibition of MAPK kinase/ERK pathways, and Ang(1-7)-Mas antagonizes the antiadipogenic effect of AngII-AT1 by inhibiting the AngII-AT1-triggered MAPK kinase/ERK pathway. The autocrine regulation of the AngII/AT1-ACE2-Ang(1-7)/Mas axis upon adipogenesis has also been revealed. This study suggests the importance of the local regulation of the delicately balanced angiotensin system upon adipogenesis and its potential as a novel therapeutic target for obesity and related metabolic disorders.

Discovery and validation of the tumor-suppressive function of long noncoding RNA PANDA in human diffuse large B-cell lymphoma through the inactivation of MAPK/ERK signaling pathway.

PubMed

Wang, Yingjun; Zhang, Mingzhi; Xu, Huanan; Wang, Yifei; Li, Zhaoming; Chang, Yu; Wang, Xinhuan; Fu, Xiaorui; Zhou, Zhiyuan; Yang, Siyuan; Wang, Bei; Shang, Yufeng

2017-09-22

Diffuse large B-cell lymphoma (DLBCL) is one of the leading causes of cancer-related mortality, and responds badly to existing treatment. Thus, it is of urgent need to identify novel prognostic markers and therapeutic targets of DLBCL. Recent studies have shown that long non-coding RNAs (lncRNAs) play an important role in the development of cancer. By using the next generation HiSeq sequencing assay, we determined lncRNAs exhibiting differential expression between DLBCL patients and healthy controls. Then, RT-qPCR was performed for identification in clinical samples and cell materials, and lncRNA PANDA was verified to be down-regulated in DLBCL patients and have considerable diagnostic potential. In addition, decreased serum PANDA level was correlated to poorer clinical outcome and lower overall survival in DLBCL patients. Subsequently, we determined the experimental role of lncRNA PANDA in DLBCL progression. Luciferase reporter assay and chromatin immunoprecipitation assay suggested that lncRNA PANDA was induced by p53 and p53 interacts with the promoter region of PANDA. Cell functional assay further indicated that PANDA functioned as a tumor suppressor gene through the suppression of cell growth by a G0/G1 cell cycle arrest in DLBCL. More importantly, Cignal Signal Transduction Reporter Array and western blot assay showed that lncRNA PANDA inactivated the MAPK/ERK signaling pathway. In conclusion, our integrated approach demonstrates that PANDA in DLBCL confers a tumor suppressive function through inhibiting cell proliferation and silencing MAPK/ERK signaling pathway. Thus, PANDA may be a promising therapeutic target for patients with DLBCL.

ROLE OF GRB2-ASSOCIATED BINDER 1 (GAB1) IN EPIDERMAL GROWTH FACTOR RECEPTOR (EGFR)-INDUCED SIGNALING IN HEAD AND NECK SQUAMOUS CELL CARCINOMA

PubMed Central

Hoeben, A.; Martin, D.; Clement, P. M.; Cools, J.; Gutkind, J. S.

2012-01-01

The Epidermal Growth Factor Receptor (EGFR) plays an important role in the pathogenesis of head and neck squamous cell carcinoma (HNSCC). Despite the high expression of EGFR in HNSCC, EGFR inhibitors have only limited success as monotherapy. The Grb2-associated binder (GAB) family of adaptor proteins acts as docking/scaffolding molecules downstream of tyrosine kinase receptors. We hypothesized that GAB1 may amplify EGFR-induced signaling in HNSCCs and therefore could play a role in the reduced sensitivity of HNSCC to EGFR inhibitors. We used representative human HNSCC cell lines overexpressing wild type EGFR, and expressing GAB1 but not GAB2. We demonstrated that baseline Akt and MAPK signaling were reduced in HNSCC cells in which GAB1 expression was reduced. Furthermore, the maximal EGF-induced activation of the Akt and MAPK pathway was reduced and delayed, and the duration of the EGF-induced activation of these pathways was reduced in cells with GAB1 knock-down. In agreement with this, HNSCC cells in which GAB1 levels were reduced showed an increased sensitivity to the EGFR inhibitor gefitinib. Our work demonstrates that GAB1 plays an important role as part of the mechanism of by which EGFR induces induced activation of the MAPK and AKT pathway. Our results identify GAB1 as an amplifier of the EGFR-initiated signaling, which may also interfere with EGFR degradation. These findings support the emerging notion that reducing GAB1 function may sensitize HNSCC to EGFR inhibitors, hence representing a new therapeutic target HNSCC treatment in combination with EGFR targeting agents. PMID:22865653

In silico pathway analysis in cervical carcinoma reveals potential new targets for treatment

PubMed Central

van Dam, Peter A.; van Dam, Pieter-Jan H. H.; Rolfo, Christian; Giallombardo, Marco; van Berckelaer, Christophe; Trinh, Xuan Bich; Altintas, Sevilay; Huizing, Manon; Papadimitriou, Kostas; Tjalma, Wiebren A. A.; van Laere, Steven

2016-01-01

An in silico pathway analysis was performed in order to improve current knowledge on the molecular drivers of cervical cancer and detect potential targets for treatment. Three publicly available Affymetrix gene expression data-sets (GSE5787, GSE7803, GSE9750) were retrieved, vouching for a total of 9 cervical cancer cell lines (CCCLs), 39 normal cervical samples, 7 CIN3 samples and 111 cervical cancer samples (CCSs). Predication analysis of microarrays was performed in the Affymetrix sets to identify cervical cancer biomarkers. To select cancer cell-specific genes the CCSs were compared to the CCCLs. Validated genes were submitted to a gene set enrichment analysis (GSEA) and Expression2Kinases (E2K). In the CCSs a total of 1,547 probe sets were identified that were overexpressed (FDR < 0.1). Comparing to CCCLs 560 probe sets (481 unique genes) had a cancer cell-specific expression profile, and 315 of these genes (65%) were validated. GSEA identified 5 cancer hallmarks enriched in CCSs (P < 0.01 and FDR < 0.25) showing that deregulation of the cell cycle is a major component of cervical cancer biology. E2K identified a protein-protein interaction (PPI) network of 162 nodes (including 20 drugable kinases) and 1626 edges. This PPI-network consists of 5 signaling modules associated with MYC signaling (Module 1), cell cycle deregulation (Module 2), TGFβ-signaling (Module 3), MAPK signaling (Module 4) and chromatin modeling (Module 5). Potential targets for treatment which could be identified were CDK1, CDK2, ABL1, ATM, AKT1, MAPK1, MAPK3 among others. The present study identified important driver pathways in cervical carcinogenesis which should be assessed for their potential therapeutic drugability. PMID:26701206

Hypoglycemic Effect of Opuntia ficus-indica var. saboten Is Due to Enhanced Peripheral Glucose Uptake through Activation of AMPK/p38 MAPK Pathway.

PubMed

Leem, Kang-Hyun; Kim, Myung-Gyou; Hahm, Young-Tae; Kim, Hye Kyung

2016-12-09

Opuntia ficus-indica var. saboten (OFS) has been used in traditional medicine for centuries to treat several illnesses, including diabetes. However, detailed mechanisms underlying hypoglycemic effects remain unclear. In this study, the mechanism underlying the hypoglycemic activity of OFS was evaluated using in vitro and in vivo systems. OFS treatment inhibited α-glucosidase activity and intestinal glucose absorption assessed by Na⁺-dependent glucose uptake using brush border membrane vesicles. AMP-activated protein kinase (AMPK) is widely recognized as an important regulator of glucose transport in skeletal muscle, and p38 mitogen-activated protein kinase (MAPK) has been proposed to be a component of AMPK-mediated signaling. In the present study, OFS dose-dependently increased glucose uptake in L6 muscle cells. The AMPK and p38 MAPK phosphorylations were stimulated by OFS, and inhibitors of AMPK (compound C ) and p38 MAPK (SB203580) abolished the effects of OFS. Furthermore, OFS increased glucose transporter 4 (GLUT4) translocation to the plasma membrane. OFS administration (1 g/kg and 2 g/kg body weight) in db/db mice dose-dependently ameliorated hyperglycemia, hyperinsulinemia, and glucose tolerance. Insulin resistance assessed by homeostasis model assessment of insulin resistance and quantitative insulin sensitivity check index were also dose-dependently improved with OFS treatment. OFS administration improved pancreatic function through increased β-cell mass in db/db mice. These findings suggest that OFS acts by inhibiting glucose absorption from the intestine and enhancing glucose uptake from insulin-sensitive muscle cells through the AMPK/p38 MAPK signaling pathway.

Hypoglycemic Effect of Opuntia ficus-indica var. saboten Is Due to Enhanced Peripheral Glucose Uptake through Activation of AMPK/p38 MAPK Pathway

PubMed Central

Leem, Kang-Hyun; Kim, Myung-Gyou; Hahm, Young-Tae; Kim, Hye Kyung

2016-01-01

Opuntia ficus-indica var. saboten (OFS) has been used in traditional medicine for centuries to treat several illnesses, including diabetes. However, detailed mechanisms underlying hypoglycemic effects remain unclear. In this study, the mechanism underlying the hypoglycemic activity of OFS was evaluated using in vitro and in vivo systems. OFS treatment inhibited α-glucosidase activity and intestinal glucose absorption assessed by Na+-dependent glucose uptake using brush border membrane vesicles. AMP-activated protein kinase (AMPK) is widely recognized as an important regulator of glucose transport in skeletal muscle, and p38 mitogen-activated protein kinase (MAPK) has been proposed to be a component of AMPK-mediated signaling. In the present study, OFS dose-dependently increased glucose uptake in L6 muscle cells. The AMPK and p38 MAPK phosphorylations were stimulated by OFS, and inhibitors of AMPK (compound C) and p38 MAPK (SB203580) abolished the effects of OFS. Furthermore, OFS increased glucose transporter 4 (GLUT4) translocation to the plasma membrane. OFS administration (1 g/kg and 2 g/kg body weight) in db/db mice dose-dependently ameliorated hyperglycemia, hyperinsulinemia, and glucose tolerance. Insulin resistance assessed by homeostasis model assessment of insulin resistance and quantitative insulin sensitivity check index were also dose-dependently improved with OFS treatment. OFS administration improved pancreatic function through increased β-cell mass in db/db mice. These findings suggest that OFS acts by inhibiting glucose absorption from the intestine and enhancing glucose uptake from insulin-sensitive muscle cells through the AMPK/p38 MAPK signaling pathway. PMID:27941667

Therapeutical relevance of MAP-kinase inhibitors in renal diseases: current knowledge and future clinical perspectives.

PubMed

Grande, M Teresa; López-Novoa, José M

2008-01-01

Renal failure, both acute and chronic, represents an important health problem by its social, sanitary and economic aspects. Mitogen-activated protein kinases (MAPK) are a family of mediators involved in the transduction of extracellular stimuli to intracellular responses. The best studied members of this family are extracellular signal-regulated kinases 1 and 2 (ERK1 and ERK2), Jun NH(2)-terminal kinase (JNK), p38 kinase and extracellular signal regulated kinases 5 (ERK5) also known as big MAP Kinase 1 (BMK1). MAPKs plays a role in regulating renal function and all these pathways have been demonstrated to be activated in many "in vivo" and cellular models or renal failure. As MAP kinases are key regulators in the control of cell proliferation and cell death, many more or less specific inhibitors of these pathways are being developed for the treatment of tumors. The purpose of this review is to examine the data available on the role of MAPKs activation in "in vivo" models of renal failure, as well as in different renal cell types (especially in mesangial cells, podocytes, tubular epithelial cells and fibroblasts) subjected to stress or damage. We have also reviewed the effect of MAPKs inhibition on renal damage, both "in vivo" and "in vitro". Data collected allow to suggest that therapy of chronic and acute renal disease with MAPKs inhibitors is a promising therapeutic area, although much more basic and clinical studies are necessary before this kind of therapy can be used in the everyday clinic.

Mechanisms involved in p53 downregulation by leptin in trophoblastic cells.

PubMed

Toro, Ayelén Rayen; Pérez-Pérez, Antonio; Corrales Gutiérrez, Isabel; Sánchez-Margalet, Víctor; Varone, Cecilia Laura

2015-11-01

Leptin, a 16-kDa polypeptide hormone, is produced by the adipocyte and can also be synthesized by placenta. We previously demonstrated that leptin promotes proliferation and survival in placenta, in part mediated by the p53 pathway. In this work, we investigated the mechanisms involved in leptin down-regulation of p53 level. The human first trimester cytotrophoblastic Swan-71 cell line and human placental explants at term were used. In order to study the late phase of apoptosis, triggered by serum deprivation, experiments of DNA fragmentation were carried out. Exogenous leptin added to human placental explants, showed a decrease on DNA ladder formation and MAPK pathway is involved in this leptin effect. We also found that under serum deprivation condition, leptin decreases p53 levels and the inhibitory leptin effect is lost when cells were pretreated with 50 μM PD98059 or 10 μM LY29004; or were transfected with dominant negative mutants of intermediates of these pathways, suggesting that MAPK and PI3K signaling pathways are necessaries for leptin action. Additionally, leptin diminished Ser-46 p53 phosphorylation and this effect in placental explants was mediated by the activation of MAPK and PI3K pathways. Finally, in order to assess leptin effect on p53 half-life experiments with cycloheximide were performed and MDM-2 expression was analyzed. Leptin diminished p53 half-life and up-regulated MDM-2 expression. In summary, we provided evidence suggesting that leptin anti-apoptotic effect is mediated by MAPK and PI3K pathways. Copyright © 2015 Elsevier Ltd. All rights reserved.

Differences in gene expression profiles and signaling pathways in rhabdomyolysis-induced acute kidney injury.

PubMed

Geng, Xiaodong; Wang, Yuanda; Hong, Quan; Yang, Jurong; Zheng, Wei; Zhang, Gang; Cai, Guangyan; Chen, Xiangmei; Wu, Di

2015-01-01

Rhabdomyolysis is a threatening syndrome because it causes the breakdown of skeletal muscle. Muscle destruction leads to the release of myoglobin, intracellular proteins, and electrolytes into the circulation. The aim of this study was to investigate the differences in gene expression profiles and signaling pathways upon rhabdomyolysis-induced acute kidney injury (AKI). In this study, we used glycerol-induced renal injury as a model of rhabdomyolysis-induced AKI. We analyzed data and relevant information from the Gene Expression Omnibus database (No: GSE44925). The gene expression data for three untreated mice were compared to data for five mice with rhabdomyolysis-induced AKI. The expression profiling of the three untreated mice and the five rhabdomyolysis-induced AKI mice was performed using microarray analysis. We examined the levels of Cyp3a13, Rela, Aldh7a1, Jun, CD14. And Cdkn1a using RT-PCR to determine the accuracy of the microarray results. The microarray analysis showed that there were 1050 downregulated and 659 upregulated genes in the rhabdomyolysis-induced AKI mice compared to the control group. The interactions of all differentially expressed genes in the Signal-Net were analyzed. Cyp3a13 and Rela had the most interactions with other genes. The data showed that Rela and Aldh7a1 were the key nodes and had important positions in the Signal-Net. The genes Jun, CD14, and Cdkn1a were also significantly upregulated. The pathway analysis classified the differentially expressed genes into 71 downregulated and 48 upregulated pathways including the PI3K/Akt, MAPK, and NF-κB signaling pathways. The results of this study indicate that the NF-κB, MAPK, PI3K/Akt, and apoptotic pathways are regulated in rhabdomyolysis-induced AKI.

Effects of TGF-β signaling blockade on human A549 lung adenocarcinoma cell lines.

PubMed

Xu, Cheng-Cheng; Wu, Lei-Ming; Sun, Wei; Zhang, Ni; Chen, Wen-Shu; Fu, Xiang-Ning

2011-01-01

Transforming growth factor β (TGF-β) is overexpressed in a wide variety of cancer types including lung adenocarcinoma (LAC), and the TGF-β signaling pathway plays an important role in tumor development. To determine whether blockade of the TGF-β signaling pathway can inhibit the malignant biological behavior of LAC, RNA interference (RNAi) technology was used to silence the expression of TGF-β receptor, type II (TGFβRII) in the LAC cell line, A549, and its effects on cell proliferation, invasion and metastasis were examined. Three specific small interfering RNAs (siRNAs) designed for targeting human TGFβRII were transfected into A549 cells. The expression of TGFβRII was detected by Western blot analysis. Cell proliferation was measured by MTT and clonogenic assays. Cell apoptosis was assessed by flow cytometry. The invasion and metastasis of A549 cells were investigated using the wound healing and Matrigel invasion assays. The expression of PI3K, phosphorylated Smad2, Smad4, Akt, Erk1/2, P38 and MMPs was detected by Western blot analysis. The TGFβRII siRNA significantly reduced the expression of TGFβRII in A549 cells. The knockdown of TGFβRII in A549 cells resulted in the suppression of cell proliferation, invasion and metastasis and induced cell apoptosis. In addition to the Smad-dependent pathway, independent pathways including the Erk MAPK, PI3K/Akt and p38 MAPK pathways, as well as the expression of MMPs and VEGF, were inhibited. In conclusion, TGF-β signaling is required for LAC progression. Therefore, the blockade of this signaling pathway by the down-regulation of TGFβRII using SiRNA may provide a potential gene therapy for LAC.

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

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

2014-02-01

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.

Momordin Ic couples apoptosis with autophagy in human hepatoblastoma cancer cells by reactive oxygen species (ROS)-mediated PI3K/Akt and MAPK signaling pathways.

PubMed

Mi, Yashi; Xiao, Chunxia; Du, Qingwei; Wu, Wanqiang; Qi, Guoyuan; Liu, Xuebo

2016-01-01

Momordin Ic is a principal saponin constituent of Fructus Kochiae, which acts as an edible and pharmaceutical product more than 2000 years in China. Our previous research found momordin Ic induced apoptosis by PI3K/Akt and MAPK signaling pathways in HepG2 cells. While the role of autophagy in momordin Ic induced cell death has not been discussed, and the connection between the apoptosis and autophagy is not clear yet. In this work, we reported momordin Ic promoted the formation of autophagic vacuole and expression of Beclin 1 and LC-3 in a dose- and time-dependent manner. Compared with momordin Ic treatment alone, the autophagy inhibitor 3-methyladenine (3-MA) also can inhibit apoptosis, while autophagy activator rapamycin (RAP) has the opposite effect, and the apoptosis inhibitor ZVAD-fmk also inhibited autophagy induced by momordin Ic. Momordin Ic simultaneously induces autophagy and apoptosis by suppressing the ROS-mediated PI3K/Akt and activating the ROS-related JNK and P38 pathways. Additionally, momordin Ic induces apoptosis by suppressing PI3K/Akt-dependent NF-κB pathways and promotes autophagy by ROS-mediated Erk signaling pathway. Those results suggest that momordin Ic has great potential as a nutritional preventive strategy in cancer therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

HIV-1 Tat binds to SH3 domains: cellular and viral outcome of Tat/Grb2 interaction

PubMed Central

Rom, Slava; Pacifici, Marco; Passiatore, Giovanni; Aprea, Susanna; Waligorska, Agnieszka; Valle, Luis Del; Peruzzi, Francesca

2011-01-01

The Src-homology 3 (SH3) domain is one of the most frequent protein recognition modules (PRMs), being represented in signal transduction pathways and in several pathologies such as cancer and AIDS. Grb2 (growth factor receptor-bound protein 2) is an adaptor protein that contains two SH3 domains and is involved in receptor tyrosine kinase (RTK) signal transduction pathways. The HIV-1 transactivator factor Tat is required for viral replication and it has been shown to bind directly or indirectly to several host proteins, deregulating their functions. In this study, we show interaction between the cellular factor Grb2 and the HIV-1 trans-activating protein Tat. The binding is mediated by the proline-rich sequence of Tat and the SH3 domain of Grb2. As the adaptor protein Grb2 participates in a wide variety of signaling pathways, we characterized at least one of the possible downstream effects of the Tat/Grb2 interaction on the well-known IGF-1R/Raf/MAPK cascade. We show that the binding of Tat to Grb2 impairs activation of the Raf/MAPK pathway, while potentiating the PKA/Raf inhibitory pathway. The Tat/Grb2 interaction affects also viral function by inhibiting the Tat-mediated transactivation of HIV-1 LTR and viral replication in infected primary microglia. PMID:21745501

Significance of decoy receptor 3 (Dcr3) and external-signal regulated kinase 1/2 (Erk1/2) in gastric cancer.

PubMed

Yang, Donghai; Fan, Xin; Yin, Ping; Wen, Qiang; Yan, Feng; Yuan, Sibo; Liu, Bin; Zhuang, Guohong; Liu, Zhongchen

2012-06-06

Decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor (TNFR) superfamily, is associated with anti-tumor immunity suppression. It is highly expressed in many tumors, and its expression can be regulated by the MAPK/MEK/ERK signaling pathway. The MAPK/MEK/ERK pathway has been reported to be a regulator in tumor occurrence, development and clonal expansion. External-signal regulated kinase (ERK) is a vital member of this pathway. The expression of DcR3 and ERK1/2 in tumor tissues of gastric cancer patients was significantly higher than the non-cancerous group (P < 0.05). There was no statistical difference among tumor tissues from patients with different ages or gender, and even of different differentiation (P > 0.05). However, in patients with stage I gastric cancer, the DcR3 and ERK1/2 levels were significantly lower than patients with more advanced stages. DcR3 and ERK1/2 play a vital role in the development of gastric cancer, and they may be new markers for indicating the efficiency of gastric cancer treatment in the future.

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

Effects of FGF-23-mediated ERK/MAPK signaling pathway on parathyroid hormone secretion of parathyroid cells in rats with secondary hyperparathyroidism.

PubMed

Chen, Xiao-Jun; Chen, Xiong; Wu, Wen-Jun; Zhou, Qi; Gong, Xiao-Hua; Shi, Bi-Min

2018-04-10

This study is supposed to investigate the effect of FGF-23 on parathyroid hormone (PTH) secretion through ERK/MAPK signaling pathway in secondary hyperparathyroidism (SHPT) rat model. Thirty rats were equally served as the normal and SHPT groups. After transfection, parathyroid cells was assigned into blank, NC, pcDNA3.1-FGF-23, siRNA-FGF-23, U0126, and siRNA-FGF-23 + U0126 groups. The serum levels of Calcium (Ca), Phosphorus (P), alkaline phosphatase (ALP), and PTH were detected. HE and immunohistochemical (IHC) staining were used for the histopathological changes and the FGF-23, EKR1/2, and pEKR1/2 expressions. qRT-PCR and Western blotting were performed to determine the mRNA and protein expression of FGF-23, PTH, MAPK, EKR1/2, and Klotho. The proliferation, apoptosis, and cell cycle were all measured for parathyroid cells by CCK-8 assay, TUNEL staining and Flow cytometry. Compared with the normal group, the SHPT group showed increased serum levels PTH, P, ALP, and FGF-23 and mRNA and protein expressions of FGF-23 and PTH, whereas declined Ca and p-ERK1/2 expression, mRNA and protein expression of Klotho, cell apoptosis rate was reduced. Furthermore, compared to the blank and NC groups, the pcDNA3.1-FGF-23 and U0126 groups had a decreased mRNA expression of Klotho, protein expression of EKR1/2 and Klotho, and cell apoptosis rate was down-regulated, whereas the RNA and protein expressions of FGF-23 and PTH were up-regulated, and cell proliferation was elevated. The opposite results were observed in the siRNA-FGF-23 group. Our study demonstrated that FGF-23 could inhibit signaling transduction of ERK/MAPK pathway and accelerate the secretion of PTH in rats with SHPT. © 2018 Wiley Periodicals, Inc.

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

PubMed

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

2014-06-01

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

E4orf1 induction in adipose tissue promotes insulin-independent signaling in the adipocyte.

PubMed

Kusminski, Christine M; Gallardo-Montejano, Violeta I; Wang, Zhao V; Hegde, Vijay; Bickel, Perry E; Dhurandhar, Nikhil V; Scherer, Philipp E

2015-10-01

Type 2 diabetes remains a worldwide epidemic with major pathophysiological changes as a result of chronic insulin resistance. Insulin regulates numerous biochemical pathways related to carbohydrate and lipid metabolism. We have generated a novel mouse model that allows us to constitutively activate, in an inducible fashion, the distal branch of the insulin signaling transduction pathway specifically in adipocytes. Using the adenoviral 36 E4orf1 protein, we chronically stimulate locally the Ras-ERK-MAPK signaling pathway. At the whole body level, this leads to reduced body-weight gain under a high fat diet challenge. Despite overlapping glucose tolerance curves, there is a reduced requirement for insulin action under these conditions. The mice further exhibit reduced circulating adiponectin levels that ultimately lead to impaired lipid clearance, and inflamed and fibrotic white adipose tissues. Nevertheless, they are protected from diet-induced hepatic steatosis. As we observe constitutively elevated p-Akt levels in the adipocytes, even under conditions of low insulin levels, this pinpoints enhanced Ras-ERK-MAPK signaling in transgenic adipocytes as a potential alternative route to bypass proximal insulin signaling events. We conclude that E4orf1 expression in the adipocyte leads to enhanced baseline activation of the distal insulin signaling node, yet impaired insulin receptor stimulation in the presence of insulin, with important implications for the regulation of adiponectin secretion. The resulting systemic phenotype is complex, yet highlights the powerful nature of manipulating selective branches of the insulin signaling network within the adipocyte.

Protective Effect of Saccharomyces boulardii on Deoxynivalenol-Induced Injury of Porcine Macrophage via Attenuating p38 MAPK Signal Pathway.

PubMed

Chang, Chao; Wang, Kun; Zhou, Sheng-Nan; Wang, Xue-Dong; Wu, Jin-E

2017-05-01

The aims of our study were to evaluate the effects of Saccharomyces boulardii (S. boulardii) on deoxynivalenol (DON)-induced injury in porcine alveolar macrophage cells (PAMCs) and to explore the underlying mechanisms. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometric analysis, ELISA, qRT-PCR, and western blot were performed to assess whether S. boulardii could prevent DON-induced injury by p38 mitogen-activated protein kinase (p38 MAPK) signal pathway. The results showed that pretreatment with 8 μM DON could decrease the viability of PAMC and significantly increase the apoptosis rate of PAMC, whereas S. boulardii could rescue apoptotic PAMC cells induced by DON. Further experiments revealed that S. boulardii effectively reversed DON-induced cytotoxicity via downregulating the expression of TNF-α, IL-6, and IL-lβ. In addition, S. boulardii significantly alleviated DON-induced phosphorylation and mRNA expression of p38 and further increased the expression of apoptosis regulation genes Bcl-xl and Bcl-2 and inhibited the activation of Bax. Our results suggest that S. boulardii could suppress DON-induced p38 MAPK pathway activation and reduce the expression of downstream inflammatory cytokines, as well as promote the expression of anti-apoptotic genes to inhibit apoptosis induced by DON in PAMC.

Tunicamycin promotes apoptosis in leukemia cells through ROS generation and downregulation of survivin expression.

PubMed

Lim, Eun Jin; Heo, Jeonghoon; Kim, Young-Ho

2015-08-01

Tunicamycin (TN), one of the endoplasmic reticulum stress inducers, has been reported to inhibit tumor cell growth and exhibit anticarcinogenic activity. However, the mechanism by which TN initiates apoptosis remains poorly understood. In the present study, we investigated the effect of TN on the apoptotic pathway in U937 cells. We show that TN induces apoptosis in association with caspase-3 activation, generation of reactive oxygen species (ROS), and downregulation of survivin expression. P38 MAPK (mitogen-activated protein kinase) and the generation of ROS signaling pathway play crucial roles in TN-induced apoptosis in U937 cells. We hypothesized that TN-induced activation of p38 MAPK signaling pathway is responsible for cell death. To test this hypothesis, we selectively inhibited MAPK during treatment with TN. Our data demonstrated that inhibitor of p38 (SB), but not ERK (PD) or JNK (SP), partially maintained apoptosis during treatment with TN. Pre-treatment with NAC and GSH markedly prevented cell death, suggesting a role for ROS in this process. Ectopic expression of survivin in U937 cells attenuated TN-induced apoptosis by suppression of caspase-3 cleavage, mitochondrial membrane potential, and cytochrome c release in U937 cells. Taken together, our results show that TN modulates multiple components of the apoptotic response of human leukemia cells and raise the possibility of a novel therapeutic strategy for hematological malignancies.

Molecular profiling of ALDH1+ colorectal cancer stem cells reveals preferential activation of MAPK, FAK, and oxidative stress pro-survival signalling pathways.

PubMed

Vishnubalaji, Radhakrishnan; Manikandan, Muthurangan; Fahad, Mohamed; Hamam, Rimi; Alfayez, Musaad; Kassem, Moustapha; Aldahmash, Abdullah; Alajez, Nehad M

2018-03-02

Tumour heterogeneity leads to variable clinical response and inaccurate diagnostic and prognostic assessment. Cancer stem cells (CSCs) represent a subpopulation responsible for invasion, metastasis, therapeutic resistance, and recurrence in many human cancer types. However, the true identity of colorectal cancer (CRC) SCs remains elusive. Here, we aimed to characterize and define the gene expression portrait of CSCs in CRC-model SW403 cells. We found that ALDH + positive cells are clonogenic and highly proliferative; their global gene expression profiling-based molecular signature revealed gene enrichment related to DNA damage, MAPK, FAK, oxidative stress response, and Wnt signalling. ALDH + cells showed enhanced ROS stress resistance, whereas MAPK/FAK pathway pharmacologic inhibition limited their survival. Conversely, 5-fluorouracil increased the ALDH + cell fraction among the SW403, HCT116 and SW620 CRC models. Notably, analysis of ALDH1A1 and POU5F1 expression levels in cohorts of 462 or 420 patients for overall (OS) or disease-free (DFS) survival, respectively, obtained from the Cancer Genome Atlas CRC dataset, revealed strong association between elevated expression and poor OS ( p = 0.006) and poor DFS ( p = 0.05), thus implicating ALDH1A1 and POU5F1 in CRC prognosis. Our data reveal distinct molecular signature of ALDH + CSCs in CRC and suggest pathways relevant for successful targeted therapies and management of CRC.

Role of CRF Receptor Signaling in Stress Vulnerability, Anxiety, and Depression

PubMed Central

Hauger, Richard L.; Risbrough, Victoria; Oakley, Robert H.; Olivares-Reyes, J. Alberto; Dautzenberg, Frank M.

2011-01-01

Markers of hyperactive central corticotropin releasing factor (CRF) systems and CRF-related single nucleotide polymorphisms (SNPs) have been identified in patients with anxiety and depressive disorders. Designing more effective antagonists may now be guided by data showing that small molecules bind to transmembrane domains. Specifically, CRF1 receptor antagonists have been developed as novel anxiolytic and antidepressant treatments. Because CRF1 receptors become rapidly desensitized by G protein-coupled receptor kinase (GRK) and β-arrestin mechanisms in the presence of high agonist concentrations, neuronal hypersecretion of synaptic CRF alone may be insufficient to account for excessive central CRF neurotransmission in stress-induced affective pathophysiology. In addition to desensitizing receptor function, GRK phosphorylation and β-arrestin binding can shift a G protein-coupled receptor (GPCR) to signal selectively via the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK-MAPK) or Akt pathways independent of G proteins. Also, Epac-dependent CRF1 receptor signaling via the ERK-MAPK pathway has been found to potentiate brain-derived neurotrophic factor (BDNF)-stimulated TrkB signaling. Thus, genetic or acquired abnormalities in GRK and β-arrestin function may be involved in the pathophysiology of stress-induced anxiety and depression. PMID:19906236

Thrombin-induced Migration and Matrix Metalloproteinase-9 Expression Are Regulated by MAPK and PI3K Pathways in C6 Glioma Cells

PubMed Central

Kim, Jiyoung; Lee, Jae-Won; Kim, Song-In; Choi, Yong-Joon; Lee, Won-Ki; Jeong, Myung-Ja; Cha, Sang-Hoon; Lee, Hee Jae; Chun, Wanjoo

2011-01-01

Glioblastoma multiforme is one of the most common and aggressive tumors in central nervous system. It often possesses characteristic necrotic lesions with hemorrhages, which increase the chances of exposure to thrombin. Thrombin has been known as a regulator of MMP-9 expression and cancer cell migration. However, the effects of thrombin on glioma cells have not been clearly understood. In the present study, influences of thrombin on glioma cell migration were examined using Boyden chamber migration assay and thrombin-induced changes in MMP-9 expression were measured using zymography, semi-quantitative RT-PCR, and Western blotting. Furthermore, underlying signaling pathways by which thrombin induces MMP-9 expression were examined. Thrombin-induced migration and MMP-9 expression were significantly potentiated in the presence of wortmannin, a PI3K inhibitor, whereas MAPK inhibitors suppressed thrombin-induced migration and MMP-9 expression in C6 glioma cells. The present data strongly demonstrate that MAPK and PI3K pathways evidently regulate thrombin-induced migration and MMP-9 expression of C6 glioma cells. Therefore, the control of these pathways might be a beneficial therapeutic strategy for treatment of invasive glioblastoma multiforme. PMID:21994479

Signaling pathways activation by primary endodontic infectious contents and production of inflammatory mediators.

PubMed

Martinho, Frederico C; Leite, Fabio R M; Chiesa, Wanderson M M; Nascimento, Gustavo G; Feres, Magda; Gomes, Brenda P F A

2014-04-01

This study investigated the bacterial community involved in primary endodontic diseases, evaluated its ability to activate the macrophage Toll-like receptor 4 receptor through p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signaling pathways, and determined the levels of endotoxins and interleukins (interleukin [IL]-6 and -10) produced by endodontic content-stimulated macrophages. Samples were taken from 21 root canals by using sterile/apyrogenic paper points. Raw 264.7 macrophages were stimulated with root canal contents. Checkerboard DNA-DNA hybridization was used for bacterial analysis and the limulus amebocyte lysate assay for endotoxin measurement; p38 MAPK and NF-κB activation was determined by Western blot analysis. IL-6 and IL-10 were measured using the enzyme-linked immunosorbent assay. Bacteria and endotoxins were detected in 100% of the samples (21/21). The most frequently observed species were Parvimonas micra (16/21, 76%), Fusobacterium nucleatum ssp. nucleatum (15/21, 71%), and Porphyromonas endodontalis (14/21, 66%). Correlations were found between endotoxins and IL-6 and IL-10 (P < .05); p38 phosphorylation had a peak at 60 minutes, and NF-κB was quickly activated after 10 minutes of stimulation. It was concluded that the complex bacterial community was shown to be a potent activator of TLR-4 determined by the p38 MAPK and NF-κB signaling pathways, culminating in a high antigenicity against macrophages through the levels of IL-6 and IL-10, all significantly affected by endotoxin levels. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Coriolus versicolor mushroom polysaccharides exert immunoregulatory effects on mouse B cells via membrane Ig and TLR-4 to activate the MAPK and NF-κB signaling pathways.

PubMed

Yang, Shu-fa; Zhuang, Tai-feng; Si, Yan-mei; Qi, Ke-yan; Zhao, Juan

2015-03-01

This study aimed to characterize the immunopotentiating effects and immune receptors for Coriolus versicolor mushroom polysaccharides (CVP), a Chinese medicinal fungus that exerts anti-tumor activities by enhancing host immunity. Proliferation assays were used to determine whether CVP could activate splenocytes. Flow cytometry analysis and IgM and IgG detection were used to characterize CVP-binding cells. Immune receptors were analyzed in immunoprecipitation and western blot assays. The downstream signaling pathways were identified by western blotting or immunostaining. CVP significantly stimulated the proliferation of mouse splenocytes. Fluorescence-labeled CVP (fl-CVP) selectively stained mouse B cells, but not T cells. CVP induced the production of IgM and IgG1 with or without exogenous IL-4. Membrane Ig (B cell antigen-receptor, BCR) was identified as a CVP-binding protein in immunoprecipitation and western blot experiments. CVP-induced B cell proliferation could be significantly inhibited by anti-mouse immunoglobulin (Ig) blocking antibody (Fab) or in cells from TLR4-mutant mice (C3H/HeJ). Phosphorylation of ERK-1/2 and p38 MAPK were clearly increased in a time-dependent manner, as was the nuclear translocation of the cytosolic NF-κB p65 subunit after CVP stimulation. Together, we demonstrate that CVP can bind and induce B cell activation using membrane Ig and TLR-4 as potential immune receptors. CVP activates mouse B cells through the MAPK and NF-κB signaling pathways. Copyright © 2014 Elsevier Ltd. All rights reserved.

The power and promise of "rewiring" the mitogen-activated protein kinase network in prostate cancer therapeutics.

PubMed

Papatsoris, Athanasios G; Karamouzis, Michalis V; Papavassiliou, Athanasios G

2007-03-01

Prostate cancer is the most frequently diagnosed cancer among men and the second leading cause of male cancer deaths. Initially, tumor growth is androgen dependent and thus responsive to pharmacologic androgen deprivation, but there is a high rate of treatment failure because the disease evolves in an androgen-independent state. Growing evidence suggests that the Ras/mitogen-activated protein kinase (MAPK) signaling cascade represents a pivotal molecular circuitry participating directly or indirectly in prostate cancer evolution. The crucial role of the protein elements comprising this complex signal transduction network makes them potential targets for pharmacologic interference. Here, we will delineate the current knowledge regarding the involvement of the Ras/MAPK pathway in prostate carcinogenesis, spotlight ongoing research concerning the development of novel targeted agents such as the Ras/MAPK inhibitors in prostate cancer, and discuss the future perspectives of their therapeutic efficacy.

MicroRNA-761 regulates mitochondrial biogenesis in mouse skeletal muscle in response to exercise

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

Xu, Yanli; Zhao, Chaoxian; Sun, Xuewen

MicroRNAs (miRNAs) have been suggested to play critical roles in skeletal muscle in response to exercise. Previous study has shown that miR-761 was involved in a novel model regulating the mitochondrial network. However, its role in mitochondrial biogenesis remains poorly understood. Therefore, the current study was aimed to examine the effect of miR-761 on mitochondrial biogenesis in skeletal muscle. Real-time quantitative PCR analysis demonstrated that aberrantly expressed miR-761 is involved in exercise activity and miR-761 is decreased by exercise training compared with the sedentary control mice. miR-761 suppresses mitochondrial biogenesis of C{sub 2}C{sub 12} myocytes by targeting the 3′-UTR ofmore » peroxisome proliferator-activated receptor gamma (PPARγ) coactivator-1 (PGC-1α). Overexpression of miR-761 was capable of inhibiting the protein expression levels of PGC-1α. Moreover, miR-761 overexpression suppressed the p38 MAPK signaling pathway and down-regulated the expression of phosphorylated MAPK-activated protein kinase-2 (P-MK2), a downstream kinase of p38 MAPK. The phosphorylation of activating transcription factors 2 (ATF2) that plays a functional role in linking the activation of the p38 MAPK pathway to enhanced transcription of the PGC-1α was also inhibited by the overexpression of miR-761. These findings revealed a novel regulation mechanism for miR-761 in skeletal myocytes, and contributed to a better understanding of the modulation of skeletal muscle in response to exercise. - Highlights: • Endurance exercise decreases miR-761 expression in skeletal muscle. • MiR-761 suppresses mitochondrial biogenesis in C{sub 2}C{sub 12} myocytes. • MiR-761 directly targeted PGC-1α expression. • MiR-761 suppresses p38 MAPK signaling pathways in C{sub 2}C{sub 12} myocytes. • A novel mechanism for miR-761 in skeletal myocytes is demonstrated.« less

In vivo treatment with diphenyl ditelluride induces neurodegeneration in striatum of young rats: Implications of MAPK and Akt pathways

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

Heimfarth, Luana; Loureiro, Samanta Oliveira; Dutra, Márcio Ferreira

2012-10-15

In the present report 15 day-old Wistar rats were injected with 0.3 μmol of diphenyl ditelluride (PhTe){sub 2}/kg body weight and parameters of neurodegeneration were analyzed in slices from striatum 6 days afterwards. We found hyperphosphorylation of intermediate filament (IF) proteins from astrocyte (glial fibrillary acidic protein—GFAP and vimentin) and from neuron (low-, medium- and high molecular weight neurofilament subunits: NF-L, NF-M and NF-H, respectively) and increased MAPK (Erk, JNK and p38MAPK) as well as PKA activities. The treatment induced reactive astrogliosis in the striatum, evidenced by increased GFAP and vimentin immunocontent as well as their mRNA overexpression. Also, (PhTe){submore » 2} significantly increased the propidium iodide (PI) positive cells in NeuN positive population without altering PI incorporation into GFAP positive cells, indicating that in vivo exposure to (PhTe){sub 2} provoked neuronal damage. Immunohistochemistry showed a dramatic increase of GFAP staining characteristic of reactive astrogliosis. Moreover, increased caspase 3 in (PhTe){sub 2} treated striatal slices suggested apoptotic cell death. (PhTe){sub 2} exposure decreased Akt immunoreactivity, however phospho-GSK-3-β (Ser9) was unaltered, suggesting that this kinase is not directly implicated in the neurotoxicity of this compound. Therefore, the present results shed light into the mechanisms of (PhTe){sub 2}-induced neurodegeneration in rat striatum, evidencing a critical role for the MAPK and Akt signaling pathways and disruption of cytoskeletal homeostasis, which could be related with apoptotic neuronal death and astrogliosis. -- Highlights: ► Diphenyl ditelluride causes apoptotic neuronal death in the striatum of young rats. ► Diphenyl ditelluride causes reactive astrogliosis in the striatum of rats. ► Diphenyl ditelluride disrupts the homeostasis of the cytoskeleton of the striatum. ► The actions of diphenyl ditelluride are mediated by MAPK and Akt signaling pathways.« less

Overcoming cetuximab resistance in HNSCC: the role of AURKB and DUSP proteins.

PubMed

Boeckx, Carolien; Op de Beeck, Ken; Wouters, An; Deschoolmeester, Vanessa; Limame, Ridha; Zwaenepoel, Karen; Specenier, Pol; Pauwels, Patrick; Vermorken, Jan B; Peeters, Marc; Van Camp, Guy; Baay, Marc; Lardon, Filip

2014-11-28

Unraveling the underlying mechanisms of cetuximab resistance in head and neck squamous cell carcinoma (HNSCC) is of major importance as many tumors remain non-responsive or become resistant. Our microarray results suggest that "resistant" cells still exhibit RAS-MAPK pathway signaling contributing to drug resistance, as witnessed by low expression of DUSP5 and DUSP6, negative regulators of ERK1/2, and increased expression of AURKB, a key regulator of mitosis. Therefore, interrupting the RAS-MAPK pathway by an ERK1/2 inhibitor (apigenin) or an AURKB inhibitor (barasertib) might be a new strategy for overcoming cetuximab resistance in HNSCC. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Comprehensive gene- and pathway-based analysis of depressive symptoms in older adults.

PubMed

Nho, Kwangsik; Ramanan, Vijay K; Horgusluoglu, Emrin; Kim, Sungeun; Inlow, Mark H; Risacher, Shannon L; McDonald, Brenna C; Farlow, Martin R; Foroud, Tatiana M; Gao, Sujuan; Callahan, Christopher M; Hendrie, Hugh C; Niculescu, Alexander B; Saykin, Andrew J

2015-01-01

Depressive symptoms are common in older adults and are particularly prevalent in those with or at elevated risk for dementia. Although the heritability of depression is estimated to be substantial, single nucleotide polymorphism-based genome-wide association studies of depressive symptoms have had limited success. In this study, we performed genome-wide gene- and pathway-based analyses of depressive symptom burden. Study participants included non-Hispanic Caucasian subjects (n = 6,884) from three independent cohorts, the Alzheimer's Disease Neuroimaging Initiative (ADNI), the Health and Retirement Study (HRS), and the Indiana Memory and Aging Study (IMAS). Gene-based meta-analysis identified genome-wide significant associations (ANGPT4 and FAM110A, q-value = 0.026; GRM7-AS3 and LRFN5, q-value = 0.042). Pathway analysis revealed enrichment of association in 105 pathways, including multiple pathways related to ERK/MAPK signaling, GSK3 signaling in bipolar disorder, cell development, and immune activation and inflammation. GRM7, ANGPT4, and LRFN5 have been previously implicated in psychiatric disorders, including the GRM7 region displaying association with major depressive disorder. The ERK/MAPK signaling pathway is a known target of antidepressant drugs and has important roles in neuronal plasticity, and GSK3 signaling has been previously implicated in Alzheimer's disease and as a promising therapeutic target for depression. Our results warrant further investigation in independent and larger cohorts and add to the growing understanding of the genetics and pathobiology of depressive symptoms in aging and neurodegenerative disorders. In particular, the genes and pathways demonstrating association with depressive symptoms may be potential therapeutic targets for these symptoms in older adults.

BECN1-dependent CASP2 incomplete autophagy induction by binding to rabies virus phosphoprotein.

PubMed

Liu, Juan; Wang, Hailong; Gu, Jinyan; Deng, Tingjuan; Yuan, Zhuangchuan; Hu, Boli; Xu, Yunbin; Yan, Yan; Zan, Jie; Liao, Min; DiCaprio, Erin; Li, Jianrong; Su, Shuo; Zhou, Jiyong

2017-04-03

Autophagy is an essential component of host immunity and used by viruses for survival. However, the autophagy signaling pathways involved in virus replication are poorly documented. Here, we observed that rabies virus (RABV) infection triggered intracellular autophagosome accumulation and results in incomplete autophagy by inhibiting autophagy flux. Subsequently, we found that RABV infection induced the reduction of CASP2/caspase 2 and the activation of AMP-activated protein kinase (AMPK)-AKT-MTOR (mechanistic target of rapamycin) and AMPK-MAPK (mitogen-activated protein kinase) pathways. Further investigation revealed that BECN1/Beclin 1 binding to viral phosphoprotein (P) induced an incomplete autophagy via activating the pathways CASP2-AMPK-AKT-MTOR and CASP2-AMPK-MAPK by decreasing CASP2. Taken together, our data first reveals a crosstalk of BECN1 and CASP2-dependent autophagy pathways by RABV infection.

Induction of keratinocyte migration by ECa 233 is mediated through FAK/Akt, ERK, and p38 MAPK signaling.

PubMed

Singkhorn, Sawana; Tantisira, Mayuree H; Tanasawet, Supita; Hutamekalin, Pilaiwanwadee; Wongtawatchai, Tulaporn; Sukketsiri, Wanida

2018-03-13

Centella asiatica is widely considered the most important medicinal plant for treating and relieving skin diseases. Recently developed standardized extract of Centella asiatica ECa 233 has demonstrated positive effects on wound healing of incision and burn wound in rats. However, knowledge associated with wound healing mechanism of ECa 233 was scare. Therefore, this study aimed to investigate the effect and underlying molecular mechanisms of ECa 233 on the migration of a human keratinocyte cell line (HaCaT) using scratch wound healing assay. Formation of filopodia, a key protein in cell migration as well as signaling pathways possibly involved were subsequently assessed. It was found that HaCaT cell migration was significantly enhanced by ECa 233 in a concentration- and time-dependent manner. The filopodia formations were accordingly increased in exposure to ECa 233 at concentrations of 0.1-100 μg/ml. Furthermore, ECa 233 was found to significantly upregulate the expression of Rac1 and RhoA and to induce phosphorylation of FAK and Akt as well as ERK and p38 MAPK. Taken all together, it is suggestive that ECa 233 induces cell migration and subsequently promotes wound healing activity, through the activation of FAK, Akt, and MAPK signaling pathways thereby supporting the role of ECa 233 to be further developed for the clinical treatment of wound. Copyright © 2018 John Wiley & Sons, Ltd.

Asbestos exposure induces alveolar epithelial cell plasticity through MAPK/Erk signaling.

PubMed

Tamminen, Jenni A; Myllärniemi, Marjukka; Hyytiäinen, Marko; Keski-Oja, Jorma; Koli, Katri

2012-07-01

The inhalation of asbestos fibers is considered to be highly harmful, and lead to fibrotic and/or malignant disease. Epithelial-to-mesenchymal transition (EMT) is a common pathogenic mechanism in asbestos associated fibrotic (asbestosis) and malignant lung diseases. The characterization of molecular pathways contributing to EMT may provide new possibilities for prognostic and therapeutic applications. The role of asbestos as an inducer of EMT has not been previously characterized. We exposed cultured human lung epithelial cells to crocidolite asbestos and analyzed alterations in the expression of epithelial and mesenchymal marker proteins and cell morphology. Asbestos was found to induce downregulation of E-cadherin protein levels in A549 lung carcinoma cells in 2-dimensional (2D) and 3D cultures. Similar findings were made in primary small airway epithelial cells cultured in 3D conditions where the cells retained alveolar type II cell phenotype. A549 cells also exhibited loss of cell-cell contacts, actin reorganization and expression of α-smooth muscle actin (α-SMA) in 2D cultures. These phenotypic changes were not associated with increased transforming growth factor (TGF)-β signaling activity. MAPK/Erk signaling pathway was found to mediate asbestos-induced downregulation of E-cadherin and alterations in cell morphology. Our results suggest that asbestos can induce epithelial plasticity, which can be interfered by blocking the MAPK/Erk kinase activity. Copyright © 2012 Wiley Periodicals, Inc.

Metformin targets multiple signaling pathways in cancer.

PubMed

Lei, Yong; Yi, Yanhua; Liu, Yang; Liu, Xia; Keller, Evan T; Qian, Chao-Nan; Zhang, Jian; Lu, Yi

2017-01-26

Metformin, an inexpensive and well-tolerated oral agent commonly used in the first-line treatment of type 2 diabetes, has become the focus of intense research as a candidate anticancer agent. Here, we discuss the potential of metformin in cancer therapeutics, particularly its functions in multiple signaling pathways, including AMP-activated protein kinase, mammalian target of rapamycin, insulin-like growth factor, c-Jun N-terminal kinase/mitogen-activated protein kinase (p38 MAPK), human epidermal growth factor receptor-2, and nuclear factor kappaB pathways. In addition, cutting-edge targeting of cancer stem cells by metformin is summarized.

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

Park, Serk In, E-mail: serkin@korea.edu; The BK21 Plus Program for Biomedical Sciences, Korea University College of Medicine, Seoul; Department of Medicine and Center for Bone Biology, Vanderbilt University School of Medicine, Nashville, TN

The radiation stress induces cytotoxic responses of cell death as well as cytoprotective responses of cell survival. Understanding exact cellular mechanism and signal transduction pathways is important in improving cancer radiotherapy. Increasing evidence suggests that cyclic AMP response element binding protein (CREB)/activating transcription factor (ATF) family proteins act as a survival factor and a signaling molecule in response to stress. We postulated that CREB inhibition via CRE decoy oligonucleotide increases tumor cell sensitization to γ-irradiation-induced cytotoxic stress. In the present study, we demonstrate that CREB phosphorylation and CREB DNA-protein complex formation increased in time- and radiation dose-dependent manners, while theremore » was no significant change in total protein level of CREB. In addition, CREB was phosphorylated in response to γ-irradiation through p38 MAPK pathway. Further investigation revealed that CREB blockade by decoy oligonucleotides functionally inhibited transactivation of CREB, and significantly increased radiosensitivity of multiple human cancer cell lines including TP53- and/or RB-mutated cells with minimal effects on normal cells. We also demonstrate that tumor cells ectopically expressing dominant negative mutant CREB (KCREB) and the cells treated with p38 MAPK inhibitors were more sensitive to γ-irradiation than wild type parental cells or control-treated cells. Taken together, we conclude that CREB protects tumor cells from γ-irradiation, and combination of CREB inhibition plus ionizing radiation will be a promising radiotherapeutic approach. - Highlights: • γ-Irradiation induced CREB phosphorylation and CRE-directed transcription in tumor. • γ-Irradiation-induced transcriptional activation of CREB was via p38 MAPK pathway. • CRE blockade increased radiosensitivity of tumor cells but not of normal cells. • CRE decoy oligonucleotides or p38 MAPK inhibitors can be used as radiosensitizers.« less

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

Song, Xiulong, E-mail: songxiulong@hotmail.com; Wei, Zhengxi; Shaikh, Zahir A., E-mail: zshaikh@uri.edu

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. Receptormore » 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.« less

EphA2 modulates radiosensitive of hepatocellular carcinoma cells via p38/mitogen-activated protein kinase-mediated signal pathways.

PubMed

Jin, Qiao; Li, Xiangjun; Cao, Peiguo

2015-10-01

This experiment was conducted to investigate the role of EPH receptor A2 (EphA2) in the modulation of radiosensitivity of hepatic cellular cancer (HCC) cells and to determine whether p38/mitogen-activated protein kinase (p38MAPK) signaling mediated EphA2 function in this respect. The protein expressions of EphA2 and phosphorylated p38MAPK were tested in HCC and normal hepatic tissues. In HCC 97H cells, EphA2 was overexpressed and knocked out by transfection with EphA2 expression vector and EphA2-ShRNA, respectively, prior to cell exposure to low-dose irradiation. Significantly upregulated EphA2 and phosphorylated p38MAPK were observed in HCC tissues, compared with those in normal hepatic tissues. Low-dose irradiation (1 Gy) only caused minor damage to HCC 97H cells, as assessed by alterations in cell viability, apoptosis rate, and cell healing capacity (p = 0.072, p = 0.078, and p = 0.069 respectively). However, EphA2 knock-out in HCC 97H cells induced significant reduction in cell viability and cell healing capacity after these cells were subjected to low-dose irradiation. Apoptosis rate underwent dramatic increase (p < 0.01). By contrast, EphA2 overexpression in HCC 97H cells reversed these effects and enhanced cell colony formation rate, thus displaying remarkable attenuation of radiosensitivity of HCC 97H cells. Further, SB203580, a specific inhibitor of p38MAPK, was added to HCC 97H cells over-expressing EphA2. The effect of EphA2 overexpression on the radiosensitivity of HCC 97H cells was abrogated. Thus, the present study indicates that EphA2 have the ability to negatively regulate the radiosensitivity of HCC 97H cells, which mainly depends on 38MAPK-mediated signal pathways. Copyright © 2015. Published by Elsevier Taiwan.

PLCγ2 promotes apoptosis while inhibits proliferation in rat hepatocytes through PKCD/JNK MAPK and PKCD/p38 MAPK signalling.

PubMed

Chen, Xiaoguang; Lv, Qiongxia; Ma, Jun; Liu, Yumei

2018-02-11

The PLCG2 (PLCγ2) gene is a member of PLC gene family encoding transmembrane signalling enzymes involved in various biological processes including cell proliferation and apoptosis. Our earlier study indicated that PLCγ2 may be involved in the termination of regeneration of the liver which is mainly composed of hepatocytes, but its exact biological function and molecular mechanism in liver regeneration termination remains unclear. This study aims to examine the role of PLCγ2 in the growth of hepatocytes. A recombinant adenovirus expressing PLCγ2 was used to infect primary rat hepatocytes. PLCγ2 mRNA and protein levels were detected by qRT-PCR and Western blot. The subcellular location of PLCγ2 protein was tested by an immunofluorescence assay. The proliferation of hepatocytes was measured by MTT assay. The cell cycle and apoptosis were analysed by flow cytometry. Caspase-3, -8 and -9 activities were measured by a spectrophotometry method. Phosphorylation levels of PKCD, JNK and p38 in the infected cells were detected by Western blot. The possible mechanism underlying the role of PLCγ2 in hepatocyte growth was also explored by adding a signalling pathway inhibitor. Hepatocyte proliferation was dramatically reduced, while cell apoptosis was remarkably increased. The results demonstrated that PLCγ2 increased the phosphorylation of PKCD, p38 and JNK in rat hepatocytes. After PKCD activity was inhibited by the inhibitor Go 6983, the levels of both p-p38 and p-JNK MAPKs significantly decreased, and PLCγ2-induced cell proliferation inhibition and cell apoptosis were obviously reversed. This study showed that PLCγ2 regulates hepatocyte growth through PKCD-dependently activating p38 MAPK and JNK MAPK pathways; this result was experimentally based on the further exploration of the effect of PLCγ2 on hepatocyte growth in vivo. © 2018 John Wiley & Sons Ltd.

MicroRNA-24 promotes 3T3-L1 adipocyte differentiation by directly targeting the MAPK7 signaling

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

Jin, Min, E-mail: min_jin@zju.edu.cn; Wu, Yutao; Wang, Jing

Over the past years, MicroRNAs (miRNAs) act as a vital role in harmony with gene regulation and maintaining cellular homeostasis. It is well testified that miRNAshave been involved in numerous physiological and pathological processes, including embryogenesis, cell fate decision, and cellular differentiation. Adipogenesis is an organized process of cellular differentiation by which pre-adipocytes differentiate towards mature adipocytes, and it is tightly modulated by a series of transcription factors such as peroxisome proliferator-activated receptor γ (PPAR-γ) and sterol regulatory-element binding proteins 1 (SREBP1). However, the molecular mechanisms underlying the connection between miRNAs and adipogenesis-related transcription factors remain obscure. In this study,more » we unveiled that miR- 24 was remarkably upregulated during 3T3-L1 adipogenesis. Overexpression of miR-24 significantly promoted 3T3-L1 adipogenesis, as evidenced by its ability to increase the expression of PPAR-γ and SREBP1, lipid droplet formation and triglyceride (TG) accumulation. Furthermore, we found that neither ectopic expression of miR-24nor miR-24 inhibitor affect cell proliferation and cell cycle progression. Finally, we demonstrated that miR-24 plays the modulational role by directly repressing MAPK7, a key number in the MAPK signaling pathway. These data indicate that miR-24 is a novel positive regulator of adipocyte differentiation by targeting MAPK7, which provides new insights into the molecular mechanism of miRNA-mediated cellular differentiation. -- Highlights: •We firstly found miR-24 was upregulated in 3T3-L1 pre-adipocytes differentiation. •miR-24 promoted 3T3-L1 pre-adipocytes differentiation while silencing the expression of miR-24 had an opposite function. •miR-24 regulated 3T3-L1 differentiation by directly targeting MAPK7 signaling pathway. •miR-24did not affect 3T3-L1 pre-adipocytes cellular proliferation.« less

Dobesilate diminishes activation of the mitogen - activated protein kinase ERK1/2 in glioma cells

PubMed Central

Cuevas, P; Diaz-González, Diana; Garcia-Martin-Córdova, C; Sánchez, I; Lozano, Rosa Maria; Giménez-Gallego, G; Dujovny, M

2006-01-01

Fibroblast growth factors (FGFs) and their receptors, regularly expressed at high levels in gliomas, are further upregulated during the transition of the tumor from low- to high-grade malignancy, and are essential for glioma progression. FGFs induce upregulation of the mitogen-activated protein kinase (MAPK) signaling cascade in cultured glioma cells, which suggests that MAPK pathway participates in the FGF-dependent glioma development. Recently, it has been shown that dobesilate, an inhibitor of FGF mitogenic activity, shows antiproliferative and proapoptotic activities in glioma cell cultures. Accordingly, it should be expected this new synthetic FGF inhibitor to affect the activation levels of MAPK. Here we report that immunocytochemical and Western blot data unequivocally show that treatment of cell cultures with dobesilate causes a significant decrease of the intracellular levels of ERK1/2 activation, one of the components of the MAPK signalling cascade. This finding supports an important role for dobesilate in glioma growth, suggesting that dobesilate should be a treatment to be born in mind for glioma management. PMID:16563234

MEK1 inhibits cardiac PPARα activity by direct interaction and prevents its nuclear localization.

PubMed

el Azzouzi, Hamid; Leptidis, Stefanos; Bourajjaj, Meriem; van Bilsen, Marc; da Costa Martins, Paula A; De Windt, Leon J

2012-01-01

The response of the postnatal heart to growth and stress stimuli includes activation of a network of signal transduction cascades, including the stress activated protein kinases such as p38 mitogen-activated protein kinase (MAPK), c-Jun NH2-terminal kinase (JNK) and the extracellular signal-regulated kinase (ERK1/2) pathways. In response to increased workload, the mitogen-activated protein kinase kinase (MAPKK) MEK1 has been shown to be active. Studies embarking on mitogen-activated protein kinase (MAPK) signaling cascades in the heart have indicated peroxisome-proliferators activated-receptors (PPARs) as downstream effectors that can be regulated by this signaling cascade. Despite the importance of PPARα in controlling cardiac metabolism, little is known about the relationship between MAPK signaling and cardiac PPARα signaling. Using co-immunoprecipitation and immunofluorescence approaches we show a complex formation of PPARα with MEK1 and not with ERK1/2. Binding of PPARα to MEK1 is mediated via a LXXLL motif and results in translocation from the nucleus towards the cytoplasm, hereby disabling the transcriptional activity of PPARα. Mice subjected to voluntary running-wheel exercise showed increased cardiac MEK1 activation and complex formation with PPARα, subsequently resulting in reduced PPARα activity. Inhibition of MEK1, using U0126, blunted this effect. Here we show that activation of the MEK1-ERK1/2 pathway leads to specific inhibition of PPARα transcriptional activity. Furthermore we show that this inhibitory effect is mediated by MEK1, and not by its downstream effector kinase ERK1/2, through a mechanism involving direct binding to PPARα and subsequent stimulation of PPARα export from the nucleus.

Carbon monoxide protects rat lung transplants from ischemia-reperfusion injury via a mechanism involving p38 MAPK pathway.

PubMed

Kohmoto, J; Nakao, A; Stolz, D B; Kaizu, T; Tsung, A; Ikeda, A; Shimizu, H; Takahashi, T; Tomiyama, K; Sugimoto, R; Choi, A M K; Billiar, T R; Murase, N; McCurry, K R

2007-10-01

Carbon monoxide (CO) provides protection against oxidative stress via anti-inflammatory and cytoprotective actions. In this study, we tested the hypothesis that a low concentration of exogenous (inhaled) CO would protect transplanted lung grafts from cold ischemia-reperfusion injury via a mechanism involving the mitogen-activated protein kinase (MAPK) signaling pathway. Lewis rats underwent orthotopic syngeneic or allogeneic left lung transplantation with 6 h of cold static preservation. Exposure of donors and recipients (1 h before and then continuously post-transplant) to 250 ppm CO resulted in significant improvement in gas exchange, reduced leukocyte sequestration, preservation of parenchymal and endothelial cell ultrastructure and reduced inflammation compared to animals exposed to air. The beneficial effects of CO were associated with p38 MAPK phosphorylation and were significantly prevented by treatment with a p38 MAPK inhibitor, suggesting that CO's efficacy is at least partially mediated by activation of p38 MAPK. Furthermore, CO markedly suppressed inflammatory events in the contralateral naïve lung. This study demonstrates that perioperative exposure of donors and recipients to CO at a low concentration can impart potent anti-inflammatory and cytoprotective effects in a clinically relevant model of lung transplantation and support further evaluation for potential clinical use.

SB203580 enhances the RV-induced loss of mitochondrial membrane potential and apoptosis in A549 cells

NASA Astrophysics Data System (ADS)

Li, Hai-yang; Zhuang, Cai-ping; Wang, Xiao-ping; Chen, Tong-sheng

2012-03-01

Resveratrol (RV), a naturally occurring phytoalexin, is known to possess a wide spectrum of chemopreventive and chemotherapeutic effects in various stages of human tumors. p38, a member of the mitogen-activated protein kinase (MAPK) superfamily, is always activated by some extracellular stimulus to regulate many cellular signal transduction pathways, such as apoptosis, proliferation, and inflammation and so on. In this report, we assessed the effect of SB203580, a specific inhibitor of p38 MAPK signaling pathway, on the RV-induced apoptosis in human lung adenocarcinoma (A549) cells. CCK-8 assay showed that pretreatment with SB203580 significantly enhanced the cytotoxicity of RV, which was further verified by analyzing the phosphatidylserine externalization using flow cytometry. In order to further confirm whether SB203580 accelerated apoptosis via the intrinsic apoptosis pathway, we analyzed the dysfunction of mitochondrial membrane potential (Δψm) of cells stained with rhodamine 123 by using flow cytometry after treatment with RV in the absence and presence of SB203580. Our data for the first time reported that p38 inhibitor SB203580 enhanced the RV-induced apoptosis via a mitochondrial pathway.

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.

PubMed

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 1-3μM 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. Copyright © 2015 Elsevier Inc. All rights reserved.

c-Raf/MEK/ERK pathway controls protein kinase C-mediated p70S6K activation in adult cardiac muscle cells.

PubMed

Iijima, Yoshihiro; Laser, Martin; Shiraishi, Hirokazu; Willey, Christopher D; Sundaravadivel, Balasubramanian; Xu, Lin; McDermott, Paul J; Kuppuswamy, Dhandapani

2002-06-21

p70S6 kinase (S6K1) plays a pivotal role in hypertrophic cardiac growth via ribosomal biogenesis. In pressure-overloaded myocardium, we show S6K1 activation accompanied by activation of protein kinase C (PKC), c-Raf, and mitogen-activated protein kinases (MAPKs). To explore the importance of the c-Raf/MAPK kinase (MEK)/MAPK pathway, we stimulated adult feline cardiomyocytes with 12-O-tetradecanoylphorbol-13-acetate (TPA), insulin, or forskolin to activate PKC, phosphatidylinositol-3-OH kinase, or protein kinase A (PKA), respectively. These treatments resulted in S6K1 activation with Thr-389 phosphorylation as well as mammalian target of rapamycin (mTOR) and S6 protein phosphorylation. Thr-421/Ser-424 phosphorylation of S6K1 was observed predominantly in TPA-treated cells. Dominant negative c-Raf expression or a MEK1/2 inhibitor (U0126) treatment showed a profound blocking effect only on the TPA-stimulated phosphorylation of S6K1 and mTOR. Whereas p38 MAPK inhibitors exhibited only partial effect, MAPK-phosphatase-3 expression significantly blocked the TPA-stimulated S6K1 and mTOR phosphorylation. Inhibition of mTOR with rapamycin blocked the Thr-389 but not the Thr-421/Ser-424 phosphorylation of S6K1. Therefore, during PKC activation, the c-Raf/MEK/extracellular signal-regulated kinase-1/2 (ERK1/2) pathway mediates both the Thr-421/Ser-424 and the Thr-389 phosphorylation in an mTOR-independent and -dependent manner, respectively. Together, our in vivo and in vitro studies indicate that the PKC/c-Raf/MEK/ERK pathway plays a major role in the S6K1 activation in hypertrophic cardiac growth.

Role of human amnion-derived mesenchymal stem cells in promoting osteogenic differentiation by influencing p38 MAPK signaling in lipopolysaccharide -induced human bone marrow mesenchymal stem cells.

PubMed

Wang, Yuli; Wu, Hongxia; Shen, Ming; Ding, Siyang; Miao, Jing; Chen, Ning

2017-01-01

Periodontitis is a chronic inflammatory disease induced by bacterial pathogens, which not only affect connective tissue attachments but also cause alveolar bone loss. In this study, we investigated the anti-inflammatory effects of Human amnion-derived mesenchymal stem cells (HAMSCs) on human bone marrow mesenchymal stem cells (HBMSCs) under lipopolysaccharide (LPS)-induced inflammatory conditions. Proliferation levels were measured by flow cytometry and immunofluorescence staining of 5-ethynyl-2'-deoxyuridine (EdU). Osteoblastic differentiation and mineralization were investigated using chromogenic alkaline phosphatase activity (ALP) activity substrate assays, Alizarin red S staining, and RT-PCR analysis of HBMSCs osteogenic marker expression. Oxidative stress induced by LPS was investigated by assaying reactive oxygen species (ROS) level and superoxide dismutase (SOD) activity. Here, we demonstrated that HAMSCs increased the proliferation, osteoblastic differentiation, and SOD activity of LPS-induced HBMSCs, and down-regulated the ROS level. Moreover, our results suggested that the activation of p38 MAPK signal transduction pathway is essential for reversing the LPS-induced bone-destructive processes. SB203580, a selective inhibitor of p38 MAPK signaling, significantly suppressed the anti-inflammatory effects in HAMSCs. In conclusion, HAMSCs show a strong potential in treating inflammation-induced bone loss by influencing p38 MAPK signaling. Copyright © 2016 Elsevier Inc. All rights reserved.

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

Mitogen-Activated Protein Kinase Cascade Required for Regulation of Development and Secondary Metabolism in Neurospora crassa▿

PubMed Central

Park, Gyungsoon; Pan, Songqin; Borkovich, Katherine A.

2008-01-01

Mitogen-activated protein kinase (MAPK) signaling cascades are composed of MAPK kinase kinases (MAPKKKs), MAPK kinases (MAPKKs), and MAPKs. In this study, we characterize components of a MAPK cascade in Neurospora crassa (mik-1, MAPKKK; mek-1, MAPKK; and mak-1, MAPK) homologous to that controlling cell wall integrity in Saccharomyces cerevisiae. Growth of basal hyphae is significantly reduced in mik-1, mek-1, and mak-1 deletion mutants on solid medium. All three mutants formed short aerial hyphae and the formation of asexual macroconidia was reduced in Δmik-1 mutants and almost abolished in Δmek-1 and Δmak-1 strains. In contrast, the normally rare asexual spores, arthroconidia, were abundant in cultures of the three mutants. Δmik-1, Δmek-1, and Δmak-1 mutants were unable to form protoperithecia or perithecia when used as females in a sexual cross. The MAK-1 MAPK was not phosphorylated in Δmik-1 and Δmek-1 mutants, consistent with the involvement of MIK-1, MEK-1, and MAK-1 in the same signaling cascade. Interestingly, we observed increased levels of mRNA and protein for tyrosinase in the mutants under nitrogen starvation, a condition favoring sexual differentiation. Tyrosinase is an enzyme that catalyzes production of the secondary metabolite l-DOPA melanin. These results implicate the MAK-1 pathway in regulation of development and secondary metabolism in filamentous fungi. PMID:18849472

Mitogen-Activated Protein Kinase Signaling in the Heart: Angels Versus Demons in a Heart-Breaking Tale

PubMed Central

ROSE, BETH A.; FORCE, THOMAS; WANG, YIBIN

2013-01-01

Among the myriad of intra-cellular signaling networks that govern the cardiac development and pathogenesis, mitogen-activated protein kinases (MAPKs) are prominent players that have been the focus of extensive investigations in the past decades. The four best characterized MAPK subfamilies, ERK1/2, JNK, p38, and ERK5, are the targets of pharmacological and genetic manipulations to uncover their roles in cardiac development, function, and diseases. However, information reported in the literature from these efforts has not yet resulted in a clear view about the roles of specific MAPK pathways in heart. Rather, controversies from contradictive results have led to a perception that MAPKs are ambiguous characters in heart with both protective and detrimental effects. The primary object of this review is to provide a comprehensive overview of the current progress, in an effort to highlight the areas where consensus is established verses the ones where controversy remains. MAPKs in cardiac development, cardiac hypertrophy, ischemia/reperfusion injury, and pathological remodeling are the main focuses of this review as these represent the most critical issues for evaluating MAPKs as viable targets of therapeutic development. The studies presented in this review will help to reveal the major challenges in the field and the limitations of current approaches and point to a critical need in future studies to gain better understanding of the fundamental mechanisms of MAPK function and regulation in the heart. PMID:20959622

Microarray Analysis of Long Noncoding RNAs in Female Diabetic Peripheral Neuropathy Patients.

PubMed

Luo, Lin; Ji, Lin-Dan; Cai, Jiang-Jia; Feng, Mei; Zhou, Mi; Hu, Su-Pei; Xu, Jin; Zhou, Wen-Hua

2018-01-01

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes mellitus (DM). Because of its controversial pathogenesis, DPN is still not diagnosed or managed properly in most patients. In this study, human lncRNA microarrays were used to identify the differentially expressed lncRNAs in DM and DPN patients, and some of the discovered lncRNAs were further validated in additional 78 samples by quantitative realtime PCR (qRT-PCR). The microarray analysis identified 446 and 1327 differentially expressed lncRNAs in DM and DPN, respectively. The KEGG pathway analysis further revealed that the differentially expressed lncRNA-coexpressed mRNAs between DPN and DM groups were significantly enriched in the MAPK signaling pathway. The lncRNA/mRNA coexpression network indicated that BDNF and TRAF2 correlated with 6 lncRNAs. The qRT-PCR confirmed the initial microarray results. These findings demonstrated that the interplay between lncRNAs and mRNA may be involved in the pathogenesis of DPN, especially the neurotrophin-MAPK signaling pathway, thus providing relevant information for future studies. © 2018 The Author(s). Published by S. Karger AG, Basel.

The C-Type Lectin OCILRP2 Costimulates EL4 T Cell Activation via the DAP12-Raf-MAP Kinase Pathway

PubMed Central

Lou, Qiang; Zhang, Wei; Liu, Guangchao; Ma, Yuanfang

2014-01-01

OCILRP2 is a typical Type-II transmembrane protein that is selectively expressed in activated T lymphocytes, dendritic cells, and B cells and functions as a novel co-stimulator of T cell activation. However, the signaling pathways underlying OCILRP2 in T cell activation are still not completely understood. In this study, we found that the knockdown of OCILRP2 expression with shRNA or the blockage of its activity by an anti-OCILRP2 antagonist antibody reduced CD3/CD28-costimulated EL4 T cell viability and IL-2 production, inhibit Raf1, MAPK3, and MAPK8 activation, and impair NFAT and NF-κB transcriptional activities. Furthermore, immunoprecipitation results indicated that OCILRP2 could interact with the DAP12 protein, an adaptor containing an intracellular ITAM motif that can transduce signals to induce MAP kinase activation for T cell activation. Our data reveal that after binding with DAP12, OCILRP2 activates the Raf-MAP kinase pathways, resulting in T cell activation. PMID:25411776

The C-type lectin OCILRP2 costimulates EL4 T cell activation via the DAP12-Raf-MAP kinase pathway.

PubMed

Lou, Qiang; Zhang, Wei; Liu, Guangchao; Ma, Yuanfang

2014-01-01

OCILRP2 is a typical Type-II transmembrane protein that is selectively expressed in activated T lymphocytes, dendritic cells, and B cells and functions as a novel co-stimulator of T cell activation. However, the signaling pathways underlying OCILRP2 in T cell activation are still not completely understood. In this study, we found that the knockdown of OCILRP2 expression with shRNA or the blockage of its activity by an anti-OCILRP2 antagonist antibody reduced CD3/CD28-costimulated EL4 T cell viability and IL-2 production, inhibit Raf1, MAPK3, and MAPK8 activation, and impair NFAT and NF-κB transcriptional activities. Furthermore, immunoprecipitation results indicated that OCILRP2 could interact with the DAP12 protein, an adaptor containing an intracellular ITAM motif that can transduce signals to induce MAP kinase activation for T cell activation. Our data reveal that after binding with DAP12, OCILRP2 activates the Raf-MAP kinase pathways, resulting in T cell activation.

Adverse effects of methylmercury (MeHg) on life parameters, antioxidant systems, and MAPK signaling pathways in the copepod Tigriopus japonicus.

PubMed

Lee, Young Hwan; Kang, Hye-Min; Kim, Duck-Hyun; Wang, Minghua; Jeong, Chang-Bum; Lee, Jae-Seong

2017-03-01

Methylmercury (MeHg) is a concerning environmental pollutant that bioaccumulates and biomagnifies in the aquatic food web. However, the effects of MeHg on marine zooplankton are poorly understood even though zooplankton are considered key mediators of the bioaccumulation and biomagnification of MeHg in high-trophic marine organisms. Here, the toxicity of MeHg in the benthic copepod Tigriopus japonicus was assessed, and its adverse effects on growth rate and reproduction were demonstrated. Antioxidant enzymatic activities were increased in the presence of MeHg, indicating that these enzymes play an important role in the defense response to MeHg, which is regulated by a complex mechanism. Subsequent activation of different patterns of mitogen-activated protein kinase (MAPK) pathways was demonstrated, providing a mechanistic approach to understand the signaling pathways involved in the effects of MeHg. Our results provide valuable information for understanding the toxicity of MeHg and the underlying defense mechanism in response to MeHg exposure in marine zooplankton. Copyright © 2017 Elsevier B.V. All rights reserved.

Anti-CD20 antibody induces the improvement of cytokine-induced killer cell activity via the STAT and MAPK/ERK signaling pathways

PubMed Central

DENG, QI; BAI, XUE; LV, HAI-RONG; XIAO, XIA; ZHAO, MING-FENG; LI, YU-MING

2015-01-01

There is a current requirement for novel therapeutic strategies for the treatment of hematopoietic tumors. Residual tumor cells are the main origin of tumor relapse. The aim of this study was to eliminate the residual tumor cells of hematopoietic tumors. Cytokine-induced killer (CIK) cells are used in immunotherapy to deplete the residual cells. However, it is necessary to increase the antitumor activity and clinical applicability of CIK cells. The present study investigated the antitumor activity of CIK cells to the SU-DHL2 human B-cell lymphoma and K562 human chronic myelogenous leukemia cell lines. CD3+CD56+ cells from healthy donors were expanded in culture with cytokines and anti-CD20 monoclonal antibody (mAb; rituximab) to generate CIK cells. A preliminary investigation of their mechanism was then performed. The increase in the cytotoxicity of the CIK cells induced by the anti-CD20 mAb was associated with an increase in the expression of cytotoxic factors. The expression of components of the signal transducer and activator of transcription (STAT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathways was found to increase. Upregulation of the expression of STAT1, STAT3 and STAT5 is important as these co-stimulatory molecules enhance T-cell proliferation. Activation of the MAPK signaling pathway is a possible mechanism for the anti-apoptosis effect on the proliferation of CIK cells. In conclusion, anti-CD20 mAb may play an important role in the improvement of CIK-mediated cytotoxicity to tumor cells. These observations may aid in the improvement of the effects of immunotherapy in depleting the residual cells of hematopoietic tumors. Thus, the use of CIK cells cultured with anti-CD20 mAb could be a novel therapeutic strategy for the depletion of chemotherapy-resistant or residual cells in anaplastic large and B-cell lymphoma. PMID:25780412

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

PubMed Central

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

2014-01-01

In response to acute insults to the central nervous system, such as pathogen invasion or neuronal injuries, glial cells become activated and secrete inflammatory mediators such as nitric oxide (NO), cytokines, and chemokines. This neuroinflammation plays a crucial role in the pathophysiology of chronic neurodegenerative diseases. Endogenous ascorbate levels are significantly decreased among patients with septic encephalopathy. Using the bacterial endotoxin lipopolysaccharide (LPS) to induce neuroinflammation in primary neuron/glia cocultures, we investigated how L-ascorbate (vitamin C; Vit. C) affected neuroinflammation. LPS (100 ng/ml) induced the expression of inducible NO synthase (iNOS) and the production of NO, interleukin (IL)-6, and macrophage inflammatory protein-2 (MIP-2/CXCL2) in a time-dependent manner; however, cotreatment with Vit. C (5 or 10 mM) attenuated the LPS-induced iNOS expression and production of NO, IL-6, and MIP-2 production. The morphological features revealed after immunocytochemical staining confirmed that Vit. C suppressed LPS-induced astrocytic and microglial activation. Because Vit. C can be transported into neurons and glia via the sodium-dependent Vit. C transporter-2, we examined how Vit. C affected LPS-activated intracellular signaling in neuron/glia cocultures. The results indicated the increased activation (caused by phosphorylation) of mitogen-activated protein kinases (MAPKs), such as p38 at 30 min and extracellular signal-regulated kinases (ERKs) at 180 min after LPS treatment. The inhibition of p38 and ERK MAPK suppressed the LPS-induced production of inflammatory mediators. Vit. C also inhibited the LPS-induced activation of p38 and ERK. Combined treatments of Vit. C and the inhibitors of p38 and ERK yielded no additional inhibition compared with using the inhibitors alone, suggesting that Vit. C functions through the same signaling pathway (i.e., MAPK) as these inhibitors. Vit. C also reduced LPS-induced IκB-α degradation and NF-κB translocation. Thus, Vit. C suppressed the LPS-stimulated production of inflammatory mediators in neuron/glia cocultures by inhibiting the MAPK and NF-κB signaling pathways. PMID:24983461

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

PubMed

Huang, X; Zhang, Q

2003-08-15

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

DCPIB, a potent volume-regulated anion channel antagonist, attenuates microglia-mediated inflammatory response and neuronal injury following focal cerebral ischemia.

PubMed

Han, Qingdong; Liu, Shengwen; Li, Zhengwei; Hu, Feng; Zhang, Qiang; Zhou, Min; Chen, Jingcao; Lei, Ting; Zhang, Huaqiu

2014-01-13

Accumulating evidence indicates that extensive microglia activation-mediated local inflammation contributes to neuronal injury in cerebral ischemia. We have previously shown that 4-(2-butyl-6, 7-dichloro-2-cyclopentyl-indan-1-on-5-yl) oxobutyric acid (DCPIB), a potent volume-regulated anion channel (VRAC) inhibitor, suppresses pathological glutamate release and excitatory neurotoxicity in reversible middle cerebral artery occlusion (rMCAO) model in vivo. In the present study, we sought to determine whether DCPIB also attenuates microglia activation that could contribute to neuronal injury in the cerebral ischemia/reperfusion pathology. We show that oxygen-glucose deprivation (OGD) induced microglia proliferation, migration, and secretion of cytokines and all these pathological changes were effectively inhibited by DCPIB in vitro. In the microglia/neuron co-cultures, OGD induced neuronal damage was reduced markedly in the presence of DCPIB. In rat rMCAO animal model, DCPIB significantly attenuated microglia activation and neuronal death. Activation of mitogen-activated protein kinase (MAPK) signaling pathway is known to be a critical signaling pathway for microglia activation. We further explored a potential involvement of DCPIB in this pathway by western blot analysis. Under the conditions that MAPK pathway was activated either by lipopolysaccharides (LPS) or OGD, the levels of phosphorylated ERK1/2, JNK and p38 were reduced significantly in the presence of DCPIB. Altogether, our study demonstrated that DCPIB inhibits microglia activation potently under ischemic conditions both in vitro and in vivo. The DCPIB effect is likely attributable to both direct inhibition VRAC and indirect inhibition of MAPK pathway in microglia that are beneficial for the survival of neurons in cerebral ischemic conditions. © 2013 Elsevier B.V. All rights reserved.

3D culture of Her2+ breast cancer cells promotes AKT to MAPK switching and a loss of therapeutic response.

PubMed

Gangadhara, Sharath; Smith, Chris; Barrett-Lee, Peter; Hiscox, Stephen

2016-06-01

The Her2 receptor is overexpressed in up to 25 % of breast cancers and is associated with a poor prognosis. Around half of Her2+ breast cancers also express the estrogen receptor and treatment for such tumours can involve both endocrine and Her2-targeted therapies. However, despite preclinical data supporting the effectiveness of these agents, responses can vary widely in the clinical setting. In light of the increasing evidence pointing to the interplay between the tumour and its extracellular microenvironment as a significant determinant of therapeutic sensitivity and response here we investigated the impact of 3D matrix culture of breast cancer cells on their therapeutic sensitivity. A 3D Matrigel-based culture system was established and optimized for the growth of ER+/Her2+ breast cancer cell models. Growth of cells in response to trastuzumab and endocrine agents in 3D culture versus routine monolayer culture were assessed using cell counting and Ki67 staining. Endogenous and trastuzumab-modulated signalling pathway activity in 2D and 3D cultures were assessed using Western blotting. Breast cancer cells in 3D culture displayed an attenuated response to both endocrine agents and trastuzumab compared with cells cultured in traditional 2D monolayers. Underlying this phenomenon was an apparent matrix-induced shift from AKT to MAPK signalling; consequently, suppression of MAPK in 3D cultures restores therapeutic response. These data suggest that breast cancer cells in 3D culture display a reduced sensitivity to therapeutic agents which may be mediated by internal MAPK-mediated signalling. Targeting of adaptive pathways that maintain growth in 3D culture may represent an effective strategy to improve therapeutic response clinically.

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. Copyright © 2014 Elsevier Inc. All rights reserved.

A Chemically Modified Curcumin (CMC 2.24) Inhibits Nuclear Factor κB Activation and Inflammatory Bone Loss in Murine Models of LPS-Induced Experimental Periodontitis and Diabetes-Associated Natural Periodontitis.

PubMed

Elburki, Muna S; Rossa, Carlos; Guimarães-Stabili, Morgana R; Lee, Hsi-Ming; Curylofo-Zotti, Fabiana A; Johnson, Francis; Golub, Lorne M

2017-08-01

The purpose of this study was to assess the effect of a novel chemically modified curcumin (CMC 2.24) on NF-κB and MAPK signaling and inflammatory cytokine production in two experimental models of periodontal disease in rats. Experimental model I: Periodontitis was induced by repeated injections of LPS into the gingiva (3×/week, 3 weeks); control rats received vehicle injections. CMC 2.24, or the vehicle, was administered by daily oral gavage for 4 weeks. Experimental model II: Diabetes was induced in adult male rats by streptozotocin injection; periodontal breakdown then results as a complication of uncontrolled hyperglycemia. Non-diabetic rats served as controls. CMC 2.24, or the vehicle, was administered by oral gavage daily for 3 weeks to the diabetics. Hemimaxillae and gingival tissues were harvested, and bone loss was assessed radiographically. Gingival tissues were pooled according to the experimental conditions and processed for the analysis of matrix metalloproteinases (MMPs) and bone-resorptive cytokines. Activation of p38 MAPK and NF-κB signaling pathways was assessed by western blot. Both LPS and diabetes induced an inflammatory process in the gingival tissues associated with excessive alveolar bone resorption and increased activation of p65 (NF-κB) and p38 MAPK. In both models, the administration of CMC 2.24 produced a marked reduction of inflammatory cytokines and MMPs in the gingival tissues, decreased bone loss, and decreased activation of p65 (NF-κB) and p38 MAPK. Inhibition of these cell signaling pathways by this novel tri-ketonic curcuminoid (natural curcumin is di-ketonic) may play a role in its therapeutic efficacy in locally and systemically associated periodontitis.

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.

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

A Tumor Cell-Selective Inhibitor of Mitogen-Activated Protein Kinase Phosphatases Sensitizes Breast Cancer Cells to Lymphokine-Activated Killer Cell Activity

PubMed Central

Kaltenmeier, Christof T.; Vollmer, Laura L.; Vernetti, Lawrence A.; Caprio, Lindsay; Davis, Keanu; Korotchenko, Vasiliy N.; Day, Billy W.; Tsang, Michael; Hulkower, Keren I.; Lotze, Michael T.

2017-01-01

Dual specificity mitogen-activated protein kinase (MAPK) phosphatases [dual specificity phosphatase/MAP kinase phosphatase (DUSP-MKP)] have been hypothesized to maintain cancer cell survival by buffering excessive MAPK signaling caused by upstream activating oncogenic products. A large and diverse body of literature suggests that genetic depletion of DUSP-MKPs can reduce tumorigenicity, suggesting that hyperactivating MAPK signaling by DUSP-MKP inhibitors could be a novel strategy to selectively affect the transformed phenotype. Through in vivo structure-activity relationship studies in transgenic zebrafish we recently identified a hyperactivator of fibroblast growth factor signaling [(E)-2-benzylidene-5-bromo-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one (BCI-215)] that is devoid of developmental toxicity and restores defective MAPK activity caused by overexpression of DUSP1 and DUSP6 in mammalian cells. Here, we hypothesized that BCI-215 could selectively affect survival of transformed cells. In MDA-MB-231 human breast cancer cells, BCI-215 inhibited cell motility, caused apoptosis but not primary necrosis, and sensitized cells to lymphokine-activated killer cell activity. Mechanistically, BCI-215 induced rapid and sustained phosphorylation of extracellular signal-regulated kinase (ERK), p38, and c-Jun N-terminal kinase (JNK) in the absence of reactive oxygen species, and its toxicity was partially rescued by inhibition of p38 but not JNK or ERK. BCI-215 also hyperactivated MKK4/SEK1, suggesting activation of stress responses. Kinase phosphorylation profiling documented BCI-215 selectively activated MAPKs and their downstream substrates, but not receptor tyrosine kinases, SRC family kinases, AKT, mTOR, or DNA damage pathways. Our findings support the hypothesis that BCI-215 causes selective cancer cell cytotoxicity in part through non-redox-mediated activation of MAPK signaling, and the findings also identify an intersection with immune cell killing that is worthy of further exploration. PMID:28154014