scholarly journals Regulation and functional consequences of ADP receptor-mediated ERK2 activation in platelets

2007 ◽  
Vol 404 (2) ◽  
pp. 299-308 ◽  
Author(s):  
Analia Garcia ◽  
Haripriya Shankar ◽  
Swaminathan Murugappan ◽  
Soochong Kim ◽  
Satya P. Kunapuli
Keyword(s):  
Thromboxane A2 ◽  
Underlying Mechanism ◽  
P2y Receptors ◽  
Extracellular Calcium ◽  
Mitogen Activated Protein Kinase ◽  
Erk Activation ◽  
Erk Phosphorylation ◽  
Mitogen Activated Protein ◽  
Upstream Kinase ◽  
Adp Receptor

We have previously shown that ADP-induced thromboxane generation in platelets requires signalling events from the Gq-coupled P2Y1 receptor (platelet ADP receptor coupled to stimulation of phospholipase C) and the Gi-coupled P2Y12 receptor (platelet ADP receptor coupled to inhibition of adenylate cyclase) in addition to outside-in signalling. While it is also known that extracellular calcium negatively regulates ADP-induced thromboxane A2 generation, the underlying mechanism remains unclear. In the present study we sought to elucidate the signalling mechanisms and regulation by extracellular calcium of ADP-induced thromboxane A2 generation in platelets. ERK (extracllular-signal-regulated kinase) 2 activation occurred when outside-in signalling was blocked, indicating that it is a downstream event from the P2Y receptors. However, blockade of either P2Y1 or the P2Y12 receptors with corresponding antagonists completely abolished ERK phosphorylation, indicating that both P2Y receptors are required for ADP-induced ERK activation. Inhibitors of Src family kinases or the ERK upstream kinase MEK [MAPK (mitogen-activated protein kinase)/ERK kinase] abrogated ADP-induced ERK phosphorylation and thromboxane A2 generation. Finally ADP- or Gi+Gz-induced ERK phosphorylation was blocked in the presence of extracellular calcium. The present studies show that ERK2 is activated downstream of P2Y receptors through a complex mechanism involving Src kinases and this plays an important role in ADP-induced thromboxane A2 generation. We also conclude that extracellular calcium blocks ADP-induced thromboxane A2 generation through the inhibition of ERK activation.

Mechanism of Activation and Role of Extracellular Signal Regulated Kinase in ADP-Induced Thromboxane A2 Generation in Platelets.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3567-3567
Author(s):  
Analia Garcia ◽  
Haripriya Shankar ◽  
Satya P. Kunapuli
Keyword(s):  
Thromboxane A2 ◽  
P2y Receptors ◽  
Extracellular Calcium ◽  
Negative Regulation ◽  
Erk Activation ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Upstream Kinase ◽  
Erk2 Activation ◽  
Induced Aggregation

Abstract We have previously shown that ADP-induced thromboxane A2 generation in platelets requires co-ordinated signaling events from the Gq-coupled P2Y1 receptor and the Gi-coupled P2Y12 receptor in addition to outside-in signaling. It is also known that ADP-induced thromboxane A2 generation is completely abolished in the presence of extracellular calcium, but the mechanism of this negative regulation is not known. In this study we sought to identify the important signaling molecules in ADP-induced thromboxane A2 generation in platelets and characterize the regulation of these molecules by extracellular calcium. Erk2 activation occurred when outside-in signaling was blocked, indicating that it is a downstream event from the P2Y receptors. However, blockade of either P2Y1 or the P2Y12 receptors with corresponding antagonists completely abolished Erk phosphorylation, indicating that both P2Y receptors are required for ADP-induced Erk activation. However, blockade of Erk upstream kinase MEK had not effect on ADP-induced aggregation in aspirin-treated platelets, but dramatically inhibited aggregation as well as secretion in non-aspirinated platelets, suggesting that Erk might be important for thromboxane A2 generation. Finally, PP1 and PP2, inhibitors of Src family kinases, but not PP3, an inactive analog, abolished ADP-induced Erk phosphorylation and thromboxane A2 generation. Interestingly, ADP-induced Erk phosphorylation was completely inhibited in the presence of extracellular calcium, indicating that Erk is a key signaling molecule regulated by extracellular calcium in the negative regulation of thromboxane A2 generation. We conclude that Erk2 is activated downstream of P2Y receptors through a complex mechanism involving Src kinases and plays an important role in ADP-induced thromboxane A2 generation. We also conclude that extracellular calcium blocks ADP-induced thromboxane A2 generation through the inhibition of Erk activation.

β-Adrenergic-responsive activation of extracellular signal-regulated protein kinases in salivary cells: role of epidermal growth factor receptor and cAMP

2005 ◽  
Vol 288 (6) ◽  
pp. C1357-C1366 ◽  
Author(s):  
Chih-Ko Yeh ◽  
Paramita M. Ghosh ◽  
Howard Dang ◽  
Qun Liu ◽  
Alan L. Lin ◽  
...  
Keyword(s):  
Egf Receptor ◽  
Growth Factor Receptor ◽  
Immunoblot Analysis ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Salivary Gland Cell ◽  
Erk Activation ◽  
Transient Activation ◽  
Erk Phosphorylation ◽  
Mitogen Activated Protein

The β-adrenergic receptor agonist isoproterenol exerts growth-promoting effects on salivary glands. In this study, activation of ERKs, members of the mitogen-activated protein kinase family, by isoproterenol was examined in a human salivary gland cell line (HSY). Immunoblot analysis indicated that isoproterenol (10−5 M) induced transient activation of ERK1/2 (4.4-fold relative to basal at 10 min) similar to that caused by EGF (6.7 fold). Isoproterenol, like EGF, also induced phosphorylation of the EGF receptor. However, inhibition of EGF receptor phosphorylation by the tyrphostin AG-1478 only partially attenuated isoproterenol-induced ERK phosphorylation, whereas EGF-responsive ERK activation was completely blocked. The Gi inhibitor pertussis toxin also caused partial inhibition of isoproterenol-stimulated ERK activation. The cAMP analog 8-(4-chlorophenylthio)adenosine 3′,5′-cyclic monophosphate (CPT-cAMP) and the cAMP-elevating agents IBMX and cholera toxin produced transient ERK1/2 activation, similar to the effect of isoproterenol, in HSY cells. The stimulatory effects of isoproterenol and cAMP on ERK phosphorylation were not reduced by the PKA inhibitor H-89, whereas the Src family inhibitor 4-amino-5-(4-chlorophenyl)-7-( t-butyl)pyrazolo[3,4- d]pyrimidase (PP2) and transfection of a dominant-negative Src construct diminished isoproterenol-induced ERK activation. Isoproterenol induced marked overexpression of the cell growth-related adhesion molecule CD44, and this effect of isoproterenol was abolished by the ERK pathway inhibitor PD-98059. In summary, we show a dual mechanism of isoproterenol-induced ERK phosphorylation in HSY cells—one pathway mediated by EGF receptor transactivation and the other by an EGF receptor-independent pathway possibly mediated by cAMP. Our results also suggest that isoproterenol-induced growth of salivary tissue may involve ERK-mediated CD44 expression.

scholarly journals Phase I Pharmacokinetic and Pharmacodynamic Study of the Oral, Small-Molecule Mitogen-Activated Protein Kinase Kinase 1/2 Inhibitor AZD6244 (ARRY-142886) in Patients With Advanced Cancers

2008 ◽  
Vol 26 (13) ◽  
pp. 2139-2146 ◽  
Author(s):  
Alex A. Adjei ◽  
Roger B. Cohen ◽  
Wilbur Franklin ◽  
Clive Morris ◽  
David Wilson ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Phase Ii ◽  
Geometric Mean ◽  
Mitogen Activated Protein Kinase ◽  
Cancer Type ◽  
Ki 67 ◽  
Phase Ii Studies ◽  
Erk Phosphorylation ◽  
Mitogen Activated Protein ◽  
Protein Kinase Kinase

Purpose To assess the tolerability, pharmacokinetics (PKs), and pharmacodynamics (PDs) of the mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor AZD6244 (ARRY-142886) in patients with advanced cancer. Patients and Methods In part A, patients received escalating doses to determine the maximum-tolerated dose (MTD). In both parts, blood samples were collected to assess PK and PD parameters. In part B, patients were stratified by cancer type (melanoma v other) and randomly assigned to receive the MTD or 50% MTD. Biopsies were collected to determine inhibition of ERK phosphorylation, Ki-67 expression, and BRAF, KRAS, and NRAS mutations. Results Fifty-seven patients were enrolled. MTD in part A was 200 mg bid, but this dose was discontinued in part B because of toxicity. The 50% MTD (100 mg bid) was well tolerated. Rash was the most frequent and dose-limiting toxicity. Most other adverse events were grade 1 or 2. The PKs were less than dose proportional, with a median half-life of approximately 8 hours and inhibition of ERK phosphorylation in peripheral-blood mononuclear cells at all dose levels. Paired tumor biopsies demonstrated reduced ERK phosphorylation (geometric mean, 79%). Five of 20 patients demonstrated ≥ 50% inhibition of Ki-67 expression, and RAF or RAS mutations were detected in 10 of 26 assessable tumor samples. Nine patients had stable disease (SD) for ≥ 5 months, including two patients with SD for 19 (thyroid cancer) and 22 (uveal melanoma plus renal cancer) 28-day cycles. Conclusion AZD6244 was well tolerated with target inhibition demonstrated at the recommended phase II dose. PK analyses supported twice-daily dosing. Prolonged SD was seen in a variety of advanced cancers. Phase II studies are ongoing.

scholarly journals Paeoniflorin and Albiflorin Attenuate Neuropathic Pain via MAPK Pathway in Chronic Constriction Injury Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Jianyu Zhou ◽  
Linyuan Wang ◽  
Jingxia Wang ◽  
Chun Wang ◽  
Zhihui Yang ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Chronic Constriction Injury ◽  
Mapk Pathway ◽  
Biological Activities ◽  
Neuroprotective Effect ◽  
Interleukin 1 ◽  
Underlying Mechanism ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Necrosis Factor

Neuropathic pain remains as the most frequent cause of suffering and disability around the world. The isomers paeoniflorin (PF) and albiflorin (AF) are major constituents extracted from the roots ofPaeonia (P.) lactifloraPall. Neuroprotective effect of PF has been demonstrated in animal models of neuropathologies. However, only a few studies are related to the biological activities of AF and no report has been published on analgesic properties of AF about neuropathic pain to date. The aim of this study was to compare the effects of AF and PF against CCI-induced neuropathic pain in rat and explore the underlying mechanism. We had found that both PF and AF could inhibit the activation of p38 mitogen-activated protein kinase (p38 MAPK) pathway in spinal microglia and subsequent upregulated proinflammatory cytokines (interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α)). AF further displayed remarkable effects on inhibiting the activation of astrocytes, suppressing the overelevated expression of phosphorylation of c-Jun N-terminal kinases (p-JNK) in astrocytes, and decreasing the content of chemokine CXCL1 in the spinal cord. These results suggest that both PF and AF are potential therapeutic agents for neuropathic pain, which merit further investigation.

Synergistic Activation of Mitogen-Activated Protein Kinase by Cyclic AMP and Myeloid Growth Factors Opposes Cyclic AMP’s Growth-Inhibitory Effects

Blood ◽  
1999 ◽  
Vol 93 (2) ◽  
pp. 537-553 ◽  
Author(s):  
Angel Wai-mun Lee
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Cell Line ◽  
Mapk Pathway ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Erk Activation ◽  
Mitogen Activated Protein ◽  
Erk Activity ◽  
Myeloid Progenitors

Abstract Colony-stimulating factors (CSFs) promote the proliferation, differentiation, commitment, and survival of myeloid progenitors, whereas cyclic AMP (cAMP)-mediated signals frequently induce their growth arrest and apoptosis. The ERK/mitogen-activated protein kinase (MAPK) pathway is a target for both CSFs and cAMP. We investigated how costimulation by cAMP and colony-stimulating factor-1 (CSF-1) or interleukin-3 (IL-3) modulates MAPK in the myeloid progenitor cell line, 32D. cAMP dramatically increased ERK activity in the presence of CSF-1 or IL-3. IL-3 also synergized with cAMP to activate ERK in another myeloid cell line, FDC-P1. The increase in ERK activity was transmitted to a downstream target, p90rsk. cAMP treatment of 32D cells transfected with oncogenic Ras was found to recapitulate the superactivation of ERK seen with cAMP and CSF-1 or IL-3. ERK activation in the presence of cAMP did not appear to involve any of the Raf isoforms and was blocked by expression of dominant-negative MEK1 or treatment with a MEK inhibitor, PD98059. Although cAMP had an overall inhibitory effect on CSF-1–mediated proliferation and survival, the inhibition was markedly increased if ERK activation was blocked by PD98059. These findings suggest that upregulation of the ERK pathway is one mechanism induced by CSF-1 and IL-3 to protect myeloid progenitors from the growth-suppressive and apoptosis-inducing effects of cAMP elevations.

Protective effects of epoxyeicosatrienoic acids on human endothelial cells from the pulmonary and coronary vasculature

2006 ◽  
Vol 291 (2) ◽  
pp. H517-H531 ◽  
Author(s):  
Anuradha Dhanasekaran ◽  
Rula Al-Saghir ◽  
Bernardo Lopez ◽  
Daling Zhu ◽  
David D. Gutterman ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Survival ◽  
Kinase Inhibitor ◽  
Protective Action ◽  
Underlying Mechanism ◽  
Mitogen Activated Protein Kinase ◽  
Epoxyeicosatrienoic Acids ◽  
Protective Effects ◽  
Human Coronary Artery ◽  
Mitogen Activated Protein

Epoxyeicosatrienoic acids (EETs) are cytochrome P-450 (CYP) metabolites synthesized from the essential fatty acid arachidonic acid to generate four regioisomers, 14,15-, 11,12-, 8,9-, and 5,6-EET. Cultured human coronary artery endothelial cells (HCAECs) contain endogenous EETs that are increased by stimulation with physiological agonists such as bradykinin. Because EETs are known to modulate a number of vascular functions, including angiogenesis, we tested each of the four regioisomers to characterize their effects on survival and apoptosis of HCAECs and cultured human lung microvascular endothelial cells (HLMVECs). A single application of physiologically relevant concentration of 14,15-, 11,12-, and 8,9-EET but not 5,6-EET (0.75–300 nM) promoted concentration-dependent increase in cell survival of HLMVECs and HCAECs after removal of serum. The lipids also protected the same cells from death via the intrinsic, as well as extrinsic, pathways of apoptosis. EETs did not increase intracellular calcium concentration ([Ca2+]i) or phosphorylate mitogen-activated protein kinase p44/42 when applied to these cells, and their protective action was attenuated by the phosphotidylinositol-3 kinase inhibitor wortmannin (10 μM) but not the cyclooxygenase inhibitor indomethacin (20 μM). Our results demonstrate for the first time the capacity of EETs to enhance human endothelial cell survival by inhibiting both the intrinsic, as well as extrinsic, pathways of apoptosis, an important underlying mechanism that may promote angiogenesis and endothelial survival during atherosclerosis and related cardiovascular ailments.

scholarly journals Anti-Photoaging Effects of Four Insect Extracts by Downregulating Matrix Metalloproteinase Expression via Mitogen-Activated Protein Kinase-Dependent Signaling

Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1159 ◽  
Author(s):  
A-Rang Im ◽  
Kon-Young Ji ◽  
InWha Park ◽  
Joo Young Lee ◽  
Ki Mo Kim ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Underlying Mechanism ◽  
Treated Group ◽  
Ultraviolet B ◽  
Mitogen Activated Protein Kinase ◽  
Barrier Dysfunction ◽  
Mitogen Activated Protein ◽  
Pro Inflammatory Cytokines

Insects are some of the most diverse organisms on the planet, and have potential value as food or medicine. Here, we investigated the photoprotective properties of insect extracts using hairless mice. The alleviating wrinkle formation effects of insect extracts were evaluated by histological skin analysis to determine epidermal thickness and identify collagen fiber damage. Moreover, we investigated the ability of the insect extracts to alleviate UVB-induced changes to matrix metalloproteinases (MMPs), oxidative damage, the mitogen-activated protein kinases (MAPKs) signaling pathway, and the expression of pro-inflammatory cytokines. Insect extracts reduced UVB-induced skin winkles, epidermal thickening, and collagen breakdown, and alleviated the epidermal barrier dysfunction induced by UVB, including the increased loss of transepidermal water. Moreover, the expression of skin hydration-related markers such as hyaluronic acid, transforming growth factor-beta (TGF-β), and procollagen was upregulated in the group treated with insect extracts compared to the vehicle-treated group after ultraviolet B (UVB) exposure. UVB irradiation also upregulated the expression of MMPs, the phosphorylation of MAPKs, and pro-inflammatory cytokines, which were all attenuated by the oral administration of insect extracts. These results indicate the photoaging protection effect of insect extracts and the underlying mechanism, demonstrating the potential for clinical development.

scholarly journals Effect of Urban Particulate Matter on Vocal Fold Fibrosis through the MAPK/NF-κB Signaling Pathway

2020 ◽  
Vol 21 (18) ◽  
pp. 6643
Author(s):  
Ho-Ryun Won ◽  
Seung-Nam Jung ◽  
Min-Kyung Yeo ◽  
Shinae Yi ◽  
Lihua Liu ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Signaling Pathways ◽  
Vocal Fold ◽  
Animal Experiments ◽  
Vocal Folds ◽  
Underlying Mechanism ◽  
Nuclear Factor Κb ◽  
Mitogen Activated Protein Kinase ◽  
Histological Evaluation ◽  
Mitogen Activated Protein

Particulate matter (PM) is an environmental exposure factor that adversely affects human health. PM is a risk factor for various diseases. However, the mechanism by which PM affects the vocal folds (VF) has not yet been evaluated. Thus, we investigated the cytotoxic effects of PM on human vocal fold fibroblasts (hVFF) and the underlying signaling pathways. hVFF were isolated from human VF. The effect of PM on hVFF, and the underlying mechanism, were analyzed using Western blot, quantitative real-time polymerase chain reaction, and flow cytometry. In addition, a histological evaluation was performed in animal experiments. Cell proliferation decreased after the PM treatment. PM increased the expression of interleukin (IL)-6 and IL-1β. The generation of reactive oxygen species (ROS) in PM-treated hVFF and subsequent activation of the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathways were confirmed. Furthermore, PM increased the expression of fibrosis-related markers and induced the accumulation of collagen in the extracellular matrix. As a result, PM exposure significantly enhances the inflammatory response on VF through the ROS-mediated activation of the MAPK and NF-κB signaling pathways. In addition, PM promotes differentiation into myofibroblasts and induces fibrosis. These results suggest that PM triggers an inflammatory reaction through ROS production and causes VF fibrosis.

scholarly journals 15-deoxy-Δ12,14-prostaglandin J2Down-Regulates Activin-Induced Activin Receptor, Smad, and Cytokines Expression via Suppression of NF-κB and MAPK Signaling in HepG2 Cells

PPAR Research ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Seung-Won Park ◽  
Chunghee Cho ◽  
Byung-Nam Cho ◽  
Youngchul Kim ◽  
Tae Won Goo ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Hepg2 Cells ◽  
Mapk Pathway ◽  
Mapk Signaling ◽  
Activin A ◽  
Mitogen Activated Protein Kinase ◽  
Erk Phosphorylation ◽  
Mitogen Activated Protein ◽  
Regulatory Effects ◽  
Activin Receptors

15-Deoxy-Δ12,14-prostaglandin J2(15d-PGJ2) and activin are implicated in the control of apoptosis, cell proliferation, and inflammation in cells. We examined both the mechanism by which 15d-PGJ2regulates the transcription of activin-induced activin receptors (ActR) and Smads in HepG2 cells and the involvement of the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways in this regulation. Activin A (25 ng/mL) inhibited HepG2 cell proliferation, whereas 15d-PGJ2(2 μM and 5 μM) had no effect. Activin A and 15d-PGJ2showed different regulatory effects on ActR and Smad expression, NF-κB p65 activity and MEK/ERK phosphorylation, whereas they both decreased IL-6 production and increased IL-8 production. When co-stimulated with 15d-PGJ2and activin, 15d-PGJ2inhibited the activin-induced increases in ActR and Smad expression, and decreased activin-induced IL-6 production. However, it increased activin-induced IL-8 production. In addition, 15d-PGJ2inhibited activin-induced NF-κB p65 activity and activin-induced MEK/ERK phosphorylation. These results suggest that 15d-PGJ2suppresses activin-induced ActR and Smad expression, down-regulates IL-6 production, and up-regulates IL-8 production via suppression of NF-κB and MAPK signaling pathway in HepG2 cells. Regulation of ActR and Smad transcript expression and cytokine production involves NF-κB and the MAPK pathway via interaction with 15d-PGJ2/activin/Smad signaling.

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