Search results for "Mitogen-activated protein kinases"

Thapsigargin-stimulated MAP kinase phosphorylation via CRAC channels and PLD activation: inhibitory action of docosahexaenoic acid.

2004

AbstractThis study was conducted on human Jurkat T-cells to investigate the role of depletion of intracellular Ca2+ stores in the phosphorylation of two mitogen-activated protein kinases (MAPKs), i.e. extracellular signal-regulated kinase (ERK) 1 and ERK2, and their modulation by a polyunsaturated fatty acid, docosahexaenoic acid (DHA). We observed that thapsigargin (TG) stimulated MAPK activation by store-operated calcium (SOC) influx via opening of calcium release-activated calcium (CRAC) channels as tyrphostin-A9, a CRAC channel blocker, and two SOC influx inhibitors, econazole and SKF-96365, diminished the action of the former. TG-stimulated ERK1/ERK2 phosphorylation was also diminished…

Sterigmatocystin-induced DNA damage triggers cell-cycle arrest via MAPK in human neuroblastoma cells

2021

Sterigmatocystin (STE) is a common mycotoxin found in food and feed. Many studies showed that STE is genotoxic. However, up to now, the potential genotoxicity of STE on human neuronal system remains unknown. In this study, we explored the effect of STE on DNA damage and cell-cycle progression on human neuroblastoma SH-SY5Y cells exposed to various concentrations of STE (0.78, 1.56 and 3.12 µM) for 24 h. The results indicated that STE exposure induced DNA damage, as evidenced by DNA comet tails formation and increased γH2AX foci. Additionally, genotoxicity was confirmed by micronuclei (MN) analysis. Furthermore, we found that STE exposure led to cell-cycle arrest at the S and the G2/M phase.…

Role of nuclear factor κB and mitogen-activated protein kinase signaling in exercise-induced antioxidant enzyme adaptation

2007

Activation of nuclear factor (NF) κB and mitogen-activated protein kinase (MAPK) pathways in skeletal muscle has been shown to enhance the gene expression of several enzymes that play an important role in maintaining oxidant–antioxidant homeostasis, such as mitochondrial superoxide dismutase (MnSOD) and inducible nitric oxide synthase (iNOS). While an acute bout of exercise activates NFκB and MAPK signaling and upregulates MnSOD and iNOS, administration of chemical agents that suppress reactive oxygen species (ROS) production can cause attenuation of exercise-induced MnSOD and iNOS expression. Thus, ROS generation during exercise may have duel effects: the infliction of oxidative stress an…

Decreasing xanthine oxidase-mediated oxidative stress prevents useful cellular adaptations to exercise in rats

2005

Reactive oxygen or nitrogen species (RONS) are produced during exercise due, at least in part, to the activation of xanthine oxidase. When exercise is exhaustive they cause tissue damage; however, they may also act as signals inducing specific cellular adaptations to exercise. We have tested this hypothesis by studying the effects of allopurinol-induced inhibition of RONS production on cell signalling pathways in rats submitted to exhaustive exercise. Exercise caused an activation of mitogen-activated protein kinases (MAPKs: p38, ERK 1 and ERK 2), which in turn activated nuclear factor κB (NF-κB) in rat gastrocnemius muscle. This up-regulated the expression of important enzymes associated w…

Activation of Cardiac c-Jun NH 2 -Terminal Kinases and p38-Mitogen–Activated Protein Kinases With Abrupt Changes in Hemodynamic Load

2001

Abstract —The role of mitogen-activated protein kinase (MAPK) pathways as signal transduction intermediates of hemodynamic stress leading to cardiac hypertrophy in the adult heart is not fully established. In a rat model of pressure-overload hypertrophy, we examined whether activation of MAPK pathways, namely, the extracellular signal–regulated protein kinase (ERK), c-Jun NH 2 -terminal kinase (JNK), and the p38-MAPK pathways, occurs during rapid changes in hemodynamic load in vivo. A slight activation of ERK2 and marked increases in JNK1 and p38-MAPK activities were observed 30 minutes after aortic banding. The increase in p38-MAPK activity was accompanied by an increase in the phosphoryl…

Apoptosis induced in vascular smooth muscle cells by oxidative stress is partly prevented by pretreatment with CGRP.

2003

Activation of MAP kinase signaling pathway in the mussel Mytilus galloprovincialis as biomarker of environmental pollution

2010

Stimulation of MAP kinase signal transduction pathway by various stressful stimuli was investigated in the marine bivalve Mytilus galloprovincialis. Analyses were performed in animals exposed in laboratory to selected pollutants and in mussels collected in winter and summer along the eastern Adriatic coast (Croatia). Effects of oxidative stress, induced by tributyltin, hydrogen peroxide and water soluble fraction of diesel fuel on the activation/phosphorylation of the three Mitogen-Activated Protein Kinases (MAPKs) p38, JNK and ERK using a newly developed ELISA procedure were evaluated. MAP kinase activation was analyzed 1 h after exposure of mussels to chemical agents, and after recovery p…

P38 MAP Kinase Signaling Is Required for the Conversion of CD4+CD25− T Cells into iTreg

2008

CD4+CD25+ regulatory T cells (Treg) are important mediators of immune tolerance. A subset of Treg can be generated in the periphery by TGF-beta dependent conversion of conventional CD4+CD25− T cells into induced Treg (iTreg). In chronic viral infection or malignancy, such induced iTreg, which limit the depletion of aberrant or infected cells, may be of pathogenic relevance. To identify potential targets for therapeutic intervention, we investigated the TGF-beta signaling in Treg. In contrast to conventional CD4+ T cells, Treg exhibited marked activation of the p38 MAP kinase pathway. Inhibition of p38 MAP kinase activity prevented the TGF-beta-dependent conversion of CD4+CD25− T cells into …

Activation of MAP kinase p38 is critical for the cell-cycle–controlled suppressor function of regulatory T cells

2007

AbstractRegulatory T cells play an essential role in the control of self-tolerance and processes of adaptive immunity. Tolerogenic IL-10–modulated human dendritic cells (IL-10DCs) induce anergic T cells with strong suppressive properties (iTregs) that inhibit the activation of effector T cells. In this study, we evaluated the interaction between cell-cycle regulation and intracellular signaling in these iTregs. Analysis of signal transduction events revealed a down-regulation of the mitogen-activated protein kinases (MAPKs) Jun N-terminal kinase (JNK) and a nonactivation of extracellular-signal–regulated kinase (ERK) in contrast to a marked activation of p38 MAPK and the p38 effector MAPK-a…

Evolution of osmosensing signal transduction in Metazoa: stress-activated protein kinases p38 and JNK.

2001

Sponges (Porifera) represent the most basal branch of the Metazoa alive today. We show that two central stress-activated protein kinases involved in the osmosensing pathway, p38 mitogen-activated protein kinase (MAPK) and JNK, can complement for the ancestral MAPK Hog1 in the yeast Saccharomyces cerevisiae. S. cerevisiae mutants lacking Hog1 (hog1-Delta 1) have been complemented with the sponge SDJNK and SDp38 genes. Western blotting has revealed that, after transformation, the hog1-Delta 1+ SDJNK(sense) and hog1-Delta 1+ SDp38(sense) clones express the sponge proteins. Functional studies have demonstrated that the complemented clones grow under hyperosmotic conditions (0.6 M NaCl). Further…