Neurite outgrowth of PC12 cells is suppressed by wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase.

Intracellular phosphorylations polymorphonuclear neutrophils are mediated by kinases, including mitogen activated-protein (MAP) kinases and phosphatidylinositol 3-kinase. In the present study we demonstrate their effector functions upon both ligation of cell-surface seven-transmembrane-spanning receptors by bacterial peptide formylmethionyl-leucylphenylalanine as well as in the process of destruction of Staphylococcus aureus. To regulate neutrophil MAP kinases p38 and p44/42, specifically, we made use of their specific inhibitors 10 µM SK&F 86002 (for p38) and PD 098059 (for activating kinase of p44/42). SK&F 86002 was a potent inhibitor (by 70%) of induced antimicrobial oxygen-radical generation compared with PD 098059 (by 20%). SK&F 86002 and PD 098059 inhibited mobilization of a dominant neutrophil adhesion molecule, β2 integrin, from cytoplasmic granules to the plasma membrane by 40 and 10% respectively, and the combination of the two drugs resulted in a 90% effect. The combined effect of both drugs was moderate inhibition of bacterial destruction, despite the fact that neither compound had detectable effect on bactericidal activity if applied individually. Bacterial destruction was also inhibited by wortmannin (0.1 µM), the specific inhibitor of phosphatidylinositol 3-kinase, which had previously been described to target various other activations of the neutrophil, including oxygen-radical generation. Although the relative contribution of p38 and p44/42 MAP kinases varied, the marked effects of the combined inhibition of the kinases revealed their concerted actions to be critical for normal neutrophil function.

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c-Cbl Is Tyrosine-Phosphorylated by Interleukin-4 and Enhances Mitogenic and Survival Signals of Interleukin-4 Receptor by Linking With the Phosphatidylinositol 3′-Kinase Pathway

Blood ◽

10.1182/blood.v91.1.46.46_46_53 ◽

1998 ◽

Vol 91 (1) ◽

pp. 46-53 ◽

Cited By ~ 7

Author(s):

Hiroo Ueno ◽

Ko Sasaki ◽

Hiroaki Honda ◽

Tetsuya Nakamoto ◽

Tetsuya Yamagata ◽

...

Keyword(s):

Specific Inhibitor ◽

Pi3 Kinase ◽

Interleukin 4 ◽

Phosphatidylinositol 3 Kinase ◽

Proliferation And Differentiation ◽

Interleukin 4 Receptor ◽

Pi3 Kinase Pathway ◽

Kinase Pathway ◽

Phosphatidylinositol 3 ◽

Survival Signals

Interleukin-4 (IL-4) is a cytokine that induces both proliferation and differentiation and suppresses apoptosis of B cells. Although IL-4 has been shown to activate the phosphatidylinositol 3′ (PI3)-kinase pathway, the role of PI3 kinase in the IL-4 receptor (IL-4R) signaling remains unclear. In this study, we demonstrated that c-Cbl proto-oncogene product is inducibly phosphorylated on tyrosine residues and is associated with the p85 subunit of PI3-kinase by IL-4 stimulation. Overexpression of c-Cbl enhances the PI3-kinase activity and, at the same time, mitogenic activity and survival of cells in the presence of IL-4. However, these effects of c-Cbl were abolished by wortmannin, a specific inhibitor for the PI3 kinase pathway, or by a point mutation at tyrosine 731 of c-Cbl, which is a major binding site for p85. These results indicate that c-Cbl plays a role in linking IL-4R with the PI3 kinase pathway and thus enhancing the mitogenic and survival signals.

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Mesenchymal stem cells inhibition of chronic ethanol-induced oxidative damage via upregulation of phosphatidylinositol-3-kinase/Akt and modulation of extracellular signal-regulated kinase 1/2 activation in PC12 cells and neurons

Neuroscience ◽

10.1016/j.neuroscience.2010.01.057 ◽

2010 ◽

Vol 167 (4) ◽

pp. 1115-1124 ◽

Cited By ~ 26

Author(s):

L. Liu ◽

J.-X. Cao ◽

B. Sun ◽

H.-L. Li ◽

Y. Xia ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Oxidative Damage ◽

Pc12 Cells ◽

Chronic Ethanol ◽

Phosphatidylinositol 3 Kinase ◽

Extracellular Signal Regulated Kinase ◽

Extracellular Signal ◽

Phosphatidylinositol 3

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Phosphatidylinositol 3-Kinase and Prostaglandylinositol Cyclic Phosphate (Cyclic PIP), a Mediator of Insulin Action, in the Signal Transduction of Insulin

Biological Chemistry ◽

10.1515/bc.2000.140 ◽

2000 ◽

Vol 381 (11) ◽

pp. 1139-1141 ◽

Cited By ~ 1

Author(s):

A. Gypakis ◽

H.K. Wasner

Keyword(s):

Insulin Receptor ◽

Glucose Transport ◽

Functional Role ◽

Specific Inhibitor ◽

Insulin Receptor Substrate ◽

Phosphatidylinositol 3 Kinase ◽

Downstream Signaling ◽

Cyclic Phosphate ◽

Phosphatidylinositol 3

Abstract It has been suggested that downstream signaling from the insulin receptor to the level of the protein kinases and protein phosphatases is accomplished by prostaglandylinositol cyclic phosphate (cyclic PIP), a proposed second messenger of insulin. However, evidence points also to both phosphatidylinositol 3-kinase, which binds to the tyrosine phosphorylated insulin receptor substrate-1, and the Ras complex in insulin's downstream signaling. We have examined whether a correlation exists between these various observations. It was found that wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase, prevented insulin-induced, as well as cyclic PIP-induced activation of glucose transport, indicating that PI 3-kinase action on glucose transport involves downstream signaling of both insulin and cyclic PIP. Wortmannin has no effect on cyclic PIP synthase activity nor on the substrate production for cyclic PIP synthesis either, indicating that the functional role of PI 3-kinase is exclusively downstream of cyclic PIP.

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Initiation and maintenance of NGF-stimulated neurite outgrowth requires activation of a phosphoinositide 3-kinase

Journal of Cell Science ◽

10.1242/jcs.109.2.289 ◽

1996 ◽

Vol 109 (2) ◽

pp. 289-300 ◽

Cited By ~ 3

Author(s):

T.R. Jackson ◽

I.J. Blader ◽

L.P. Hammonds-Odie ◽

C.R. Burga ◽

F. Cooke ◽

...

Keyword(s):

Neurite Outgrowth ◽

Pc12 Cells ◽

Specific Inhibitor ◽

Morphological Differentiation ◽

Sympathetic Neuron ◽

Neuronal Morphology ◽

Regulatory Subunit ◽

Membrane Reorganization ◽

Phosphoinositide 3 Kinase

Application of nerve growth factor (NGF) to PC12 cells stimulates a programme of physiological changes leading to the development of a sympathetic neuron like phenotype, one aspect of which is the development of a neuronal morphology characterised by the outgrowth of neuritic processes. We have investigated the role of phosphoinositide 3-kinase in NGF-stimulated morphological differentiation through two approaches: firstly, preincubation with wortmannin, a reputedly specific inhibitor of phosphoinositide kinases, completely inhibited initial morphological responses to NGF, the formation of actin filament rich microspikes and subsequent neurite outgrowth. This correlated with wortmannin inhibition of NGF-stimulated phosphatidylinositol(3,4,5)trisphosphate (PtdInsP3) and phosphatidylinositol(3,4)bisphosphate (PtdIns(3,4)P2) production and with inhibition of NGF-stimulated phosphoinositide 3-kinase activity in anti-phosphotyrosine immunoprecipitates. Secondly, the overexpression of a mutant p85 regulatory subunit of the phosphoinositide 3-kinase, which cannot interact with the catalytic p110 subunit, also substantially inhibited the initiation of NGF-stimulated neurite outgrowth. In addition, we found that wortmannin caused a rapid collapse of more mature neurites formed following several days exposure of PC12 cells to NGF. These results indicate that NGF-stimulated neurite outgrowth requires the activity of a tyrosine kinase regulated PI3-kinase and suggest that the primary product of this enzyme, PtdInsP3, is a necessary second messenger for the cytoskeletal and membrane reorganization events which occur during neuronal differentiation.

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Wortmannin, a specific inhibitor of phosphatidylinositol-3-kinase, induces accumulation of DNA double-strand breaks

Journal of Radiation Research ◽

10.1093/jrr/rrz102 ◽

2020 ◽

Vol 61 (2) ◽

pp. 171-176 ◽

Cited By ~ 1

Author(s):

Makoto Ihara ◽

Kazuko Shichijo ◽

Satoshi Takeshita ◽

Takashi Kudo

Keyword(s):

Dna Damage ◽

Specific Inhibitor ◽

Double Strand Breaks ◽

Dependent Manner ◽

Dna Double Strand Breaks ◽

Phosphatidylinositol 3 Kinase ◽

Strand Breaks ◽

Γ Ray ◽

Scid Cells ◽

Phosphatidylinositol 3

Abstract Wortmannin, a fungal metabolite, is a specific inhibitor of the phosphatidylinositol 3-kinase (PI3K) family, which includes double-stranded DNA dependent protein kinase (DNA-PK) and ataxia telangiectasia mutated kinase (ATM). We investigated the effects of wortmannin on DNA damage in DNA-PK-deficient cells obtained from severe combined immunodeficient mice (SCID cells). Survival of wortmannin-treated cells decreased in a concentration-dependent manner. After treatment with 50 μM wortmannin, survival decreased to 60% of that of untreated cells. We observed that treatment with 20 and 50 μM wortmannin induced DNA damage equivalent to that by 0.37 and 0.69 Gy, respectively, of γ-ray radiation. The accumulation of DNA double-strand breaks (DSBs) in wortmannin-treated SCID cells was assessed using pulsed-field gel electrophoresis. The maximal accumulation was observed 4 h after treatment. Moreover, the presence of DSBs was confirmed by the ability of nuclear extracts from γ-ray-irradiated SCID cells to produce in vitro phosphorylation of histone H2AX. These results suggest that wortmannin induces cellular toxicity by accumulation of spontaneous DSBs through inhibition of ATM.

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Dehydroepiandrosterone Protects Vascular Endothelial Cells against Apoptosis through a Gαi Protein-Dependent Activation of Phosphatidylinositol 3-Kinase/Akt and Regulation of Antiapoptotic Bcl-2 Expression

Endocrinology ◽

10.1210/en.2006-1378 ◽

2007 ◽

Vol 148 (7) ◽

pp. 3068-3076 ◽

Cited By ~ 74

Author(s):

Dongmin Liu ◽

Hongwei Si ◽

Kathryn A. Reynolds ◽

Wei Zhen ◽

Zhenquan Jia ◽

...

Keyword(s):

Endothelial Cells ◽

Estrogen Receptor ◽

Vascular Function ◽

Vascular Endothelial Cells ◽

Specific Inhibitor ◽

Vascular Endothelial ◽

Phosphatidylinositol 3 Kinase ◽

Antiapoptotic Effect ◽

Dose Dependent ◽

Phosphatidylinositol 3

The adrenal steroid dehydroepiandrosterone (DHEA) may improve vascular function, but the mechanism is unclear. In the present study, we show that DHEA significantly increased cell viability, reduced caspase-3 activity, and protected both bovine and human vascular endothelial cells against serum deprivation-induced apoptosis. This effect was dose dependent and maximal at physiological concentrations (0.1–10 nm). DHEA stimulation of bovine aortic endothelial cells resulted in rapid and dose-dependent phosphorylation of Akt, which was blocked by LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), the upstream kinase of Akt. Accordingly, inhibition of PI3K or transfection of the cells with dominant-negative Akt ablated the antiapoptotic effect of DHEA. The induced Akt phosphorylation and subsequent cytoprotective effect of DHEA were dependent on activation of Gαi proteins, but were estrogen receptor independent, because these effects were blocked by pertussis toxin but not by the estrogen receptor inhibitor ICI182,780 or the aromatase inhibitor aminoglutethimide. Finally, DHEA enhanced antiapoptotic Bcl-2 protein expression, its promoter activity, and gene transcription attributable to the activation of the PI3K/Akt pathway. Neutralization of Bcl-2 by antibody transfection significantly decreased the antiapoptotic effect of DHEA. These findings provide the first evidence that DHEA acts as a survival factor for endothelial cells by triggering the Gαi-PI3K/Akt-Bcl-2 pathway to protect cells against apoptosis. This may represent an important mechanism underlying the vascular protective effect of DHEA.

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