Toll receptors remodel epithelia by directing planar-polarized Src and PI3K activity

2021 ◽  
Author(s):  
Masako Tamada ◽  
Jay Shi ◽  
Kia S. Bourdot ◽  
Sara Supriyatno ◽  
Karl H. Palmquist ◽  
...  
Keyword(s):  
Pi3k Activity

scholarly journals Hyperglycaemia up-regulates placental growth factor (PlGF) expression and secretion in endothelial cells via suppression of PI3 kinase-Akt signalling and activation of FOXO1

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Samir Sissaoui ◽  
Stuart Egginton ◽  
Ling Ting ◽  
Asif Ahmed ◽  
Peter W. Hewett
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Endothelial Dysfunction ◽  
Akt Activation ◽  
Forkhead Box ◽  
Pi3k Activity ◽  
Binding Sequence

AbstractPlacenta growth factor (PlGF) is a pro-inflammatory angiogenic mediator that promotes many pathologies including diabetic complications and atherosclerosis. Widespread endothelial dysfunction precedes the onset of these conditions. As very little is known of the mechanism(s) controlling PlGF expression in pathology we investigated the role of hyperglycaemia in the regulation of PlGF production in endothelial cells. Hyperglycaemia stimulated PlGF secretion in cultured primary endothelial cells, which was suppressed by IGF-1-mediated PI3K/Akt activation. Inhibition of PI3K activity resulted in significant PlGF mRNA up-regulation and protein secretion. Similarly, loss or inhibition of Akt activity significantly increased basal PlGF expression and prevented any further PlGF secretion in hyperglycaemia. Conversely, constitutive Akt activation blocked PlGF secretion irrespective of upstream PI3K activity demonstrating that Akt is a central regulator of PlGF expression. Knock-down of the Forkhead box O-1 (FOXO1) transcription factor, which is negatively regulated by Akt, suppressed both basal and hyperglycaemia-induced PlGF secretion, whilst FOXO1 gain-of-function up-regulated PlGF in vitro and in vivo. FOXO1 association to a FOXO binding sequence identified in the PlGF promoter also increased in hyperglycaemia. This study identifies the PI3K/Akt/FOXO1 signalling axis as a key regulator of PlGF expression and unifying pathway by which PlGF may contribute to common disorders characterised by endothelial dysfunction, providing a target for therapy.

Reduced expression of SRC family kinases decreases PI3K activity in NBS1 lymphoblasts

2008 ◽  
Vol 377 (1) ◽  
pp. 181-186 ◽  
Author(s):  
Daniel Sagan ◽  
Friederike Eckardt-Schupp ◽  
Hedda Eichholtz-Wirth
Keyword(s):  
Src Family Kinases ◽  
Pi3k Activity

Abstract 469: Targeting Beta Adrenergic Receptor Resensitization Aids in Preservation of Receptor Function

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Elizabeth E Martellli ◽  
Yu Sun ◽  
John George ◽  
Maradumane L Mohan ◽  
Randall Starling ◽  
...  
Keyword(s):  
Heart Failure ◽  
Small Molecule ◽  
In Silico ◽  
Adrenergic Receptor ◽  
Human Heart ◽  
Receptor Function ◽  
Human Heart Failure ◽  
Pp2a Activity ◽  
Pi3k Activity ◽  
Underlying Mechanisms

Beta adrenergic receptor (βAR) down-regulation and desensitization are hallmarks of heart failure. Traditionally, it has been considered that increased desensitization mechanisms underlie βAR dysfunction in heart failure but it is not known whether resensitization of βARs is altered and is an integral contributor to heart failure. We have previously shown that resensitization is regulated by inhibition of PP2A by I2PP2A via PI3Kγ (Vasudevan et. al., 2011), the underlying mechanisms of I2PP2A binding to PP2A are not well understood. We used PyMOL software to find the binding interaction between PP2A and I2PP2A. Based on in silico predictions, we generated a mutant PP2A that when expressed would compete out I2PP2A and inhibit I2PP2A from binding to endogenous PP2A. Expression of PP2A mutant in β2AR expressing cells showed preservation of β2AR function following stimulation as measured by reduced β2AR phosphorylation, increased cAMP generation and increased phosphatase function. We also generated a small molecule from our in silico predictions that could target the interface of I2PP2A and PP2A binding to find that disruption of the PP2A/I2PP2A interaction underlies receptor function. We will use this small molecule to look at preservation of βAR function and amelioration of cardiac function. To test whether resensitization is altered in heart failure we used plasma membrane and endosomal fractions from non-failing and paired pre- and post-LVAD samples to show PI3K activity, PP2A activity, β2AR phosphorylation and adenylyl cyclase activity as a measure of recovery in βAR function. Our studies showed that endosomal fractions from human heart failure samples had elevated PI3K activity associated with reduced PP2A activity supporting the idea that βAR resensitization is inhibited in human heart failure samples. Since human heart failure samples have inhibited resensitization we tested the underlying mechanisms regulating βAR resensitization. Thus ongoing studies suggest that targeting the resensitization of βAR could provide beneficial cardiac remodeling in conditions of chronic mechanical overload and will be further discussed.

PI3K signaling in the murine kidney inner medullary cell response to urea

2000 ◽  
Vol 278 (1) ◽  
pp. F155-F164 ◽  
Author(s):  
Zheng Zhang ◽  
Xiao-Yan Yang ◽  
Stephen P. Soltoff ◽  
David M. Cohen
Keyword(s):  
Cell Response ◽  
Sh2 Domain ◽  
Kinase Assay ◽  
Macromolecular Complex ◽  
Phosphatidylinositol 3 Kinase ◽  
Lipid Kinase ◽  
Urea Treatment ◽  
Pi3k Activity ◽  
Pi3k Inhibition ◽  
Immune Complex Kinase Assay

Growth factors and other stimuli increase the activity of phosphatidylinositol-3 kinase (PI3K), an SH2 domain-containing lipid kinase. In the murine kidney inner medullary mIMCD3 cell line, urea (200 mM) increased PI3K activity in a time-dependent fashion as measured by immune complex kinase assay. The PI3K effector, Akt, was also activated by urea as measured by anti-phospho-Akt immunoblotting. In addition, the Akt (and PI3K) effector, p70 S6 kinase, was activated by urea treatment in a PI3K-dependent fashion. PI3K inhibition potentiated the proapoptotic effect of hypertonic and urea stress. Urea treatment also induced the tyrosine phosphorylation of Shc and the recruitment to Shc of Grb2. Coexistence of activated Shc and PI3K in a macromolecular complex was suggested by the increase in PI3K activity evident in anti-Shc immunoprecipitates prepared from urea-treated cells. Taken together, these data suggest that PI3K may regulate physiological events in the renal medullary cell response to urea stress and that an upstream tyrosine kinase conferring activation of both PI3K and Shc may govern urea signaling in these cells.

scholarly journals Analysis of Signal Transduction Pathways in Human Eosinophils Activated by Chemoattractants and the T-Helper 2–Derived Cytokines Interleukin-4 and Interleukin-5

Blood ◽  
1998 ◽  
Vol 91 (7) ◽  
pp. 2547-2557 ◽  
Author(s):  
Paul J. Coffer ◽  
René C. Schweizer ◽  
Gerald R. Dubois ◽  
Tjander Maikoe ◽  
Jan-Willem J. Lammers ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Map Kinases ◽  
Platelet Activating Factor ◽  
Allergic Inflammation ◽  
Interleukin 4 ◽  
Signal Transduction Pathways ◽  
T Helper ◽  
T Helper 2 ◽  
Downstream Target ◽  
Pi3k Activity

Abstract Activation and recruitment of eosinophils in allergic inflammation is in part mediated by chemoattractants and T-helper 2 (Th2)-derived cytokines. However, little is known concerning the signal transduction mechanisms by which this activation occurs. We have investigated tyrosine kinase-mediated activation of phosphatidylinositol 3-kinase (PI3K) and compared this with the activation of the p21ras-ERK signaling pathway in human eosinophils. The related cytokines interleukin-3 (IL-3), IL-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF), all induced PI3K activity detected in antiphosphotyrosine immunoprecipitates. Furthermore, the chemoattractants platelet-activating factor (PAF), RANTES, and C5a were also able to induce phosphotyrosine-associated PI3K activity. Protein kinase B (PKB) is a downstream target of PI3K activation by growth factors. Induction of PKB phosphorylation in human eosinophils was transiently induced on activation with the cytokines IL-4 and IL-5, as well as the chemoattractants PAF, C5a, and RANTES showing a broad activation profile. Surprisingly, analysis of the activation of the mitogen-activated protein (MAP) kinases p44ERK1 and p42ERK2, showed that ERK2, but not ERK1, was transiently activated in human eosinophils after stimulation with IL-5 or PAF. Activation kinetics correlated with activation of p21ras by both cytokines and chemoattractants as measured by a novel assay for guanosine triphosphate (GTP)-loading. Finally, using specific inhibitors of both the p21ras-ERK and PI3K signaling pathways, a role was demonstrated for PI3K, but not p21ras-ERK, in activation of the serum-treated zymosan (STZ)-mediated respiratory burst in IL-5 and PAF-primed eosinophils. In summary, these data show that in human eosinophils, Th2-derived cytokines differentially activate both PI3K and MAP kinase signal transduction pathways with distinct functional consequences showing complex regulation of eosinophil effector functions.

Wortmannin inhibits insulin-stimulated activation of protein phosphatase 1 in rat cardiomyocytes

1999 ◽  
Vol 276 (5) ◽  
pp. H1520-H1526 ◽  
Author(s):  
Jane P. de Luca ◽  
Alice K. Garnache ◽  
Jill Rulfs ◽  
Thomas B. Miller
Keyword(s):  
Protein Phosphatase ◽  
Glycogen Synthase ◽  
Protein Phosphatase 1 ◽  
Rat Cardiomyocytes ◽  
Major Function ◽  
Pi3k Inhibitors ◽  
Protein Levels ◽  
Pi3k Activity ◽  
Insulin Dependent ◽  
Phosphatase Activation

A major function of insulin in target tissues is the activation of glycogen synthase. Phosphatidylinositol 3-kinase (PI3K) has been implicated in the insulin-induced activation of glycogen synthase, although the true function of this enzyme remains unclear. Data presented here demonstrate that the PI3K inhibitors wortmannin and LY-294002 block the insulin-stimulated activation of protein phosphatase 1 (PP1) in rat ventricular cardiomyocytes. This loss of phosphatase activation mimics that seen in diabetic cardiomyocytes, in which insulin stimulation fails to activate both PP1 and glycogen synthase. Interestingly, in diabetic cells, insulin stimulated PI3K activity to 300% of that in untreated controls, whereas this activity was increased by only 77% in normal cells. PI3K protein levels, however, were similar in normal and diabetic cells. Our results indicate that PI3K is involved in the stimulation of glycogen synthase activity by insulin through the regulation of PP1. The inability of insulin to stimulate phosphatase activity in diabetic cells, despite a significant increase in PI3K activity, suggests a defect in the insulin signaling pathway that contributes to the pathology of insulin-dependent diabetes.

scholarly journals Propolis Suppresses UV-Induced Photoaging in Human Skin through Directly Targeting Phosphoinositide 3-Kinase

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3790
Author(s):  
Da Hyun Kim ◽  
Joong-Hyuck Auh ◽  
Jeongyeon Oh ◽  
Seungpyo Hong ◽  
Sungbin Choi ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Human Skin ◽  
Therapeutic Potential ◽  
Skin Aging ◽  
Dermal Fibroblasts ◽  
Kinase Assay ◽  
Aging Effects ◽  
Propolis Extract ◽  
Pi3k Activity ◽  
Phosphoinositide 3 Kinase

Propolis is a resinous substance generated by bees using materials from various plant sources. It has been known to exhibit diverse bioactivities including anti-oxidative, anti-microbial, anti-inflammatory, and anti-cancer effects. However, the direct molecular target of propolis and its therapeutic potential against skin aging in humans is not fully understood. Herein, we investigated the effect of propolis on ultraviolet (UV)-mediated skin aging and its underlying molecular mechanism. Propolis suppressed UV-induced matrix metalloproteinase (MMP)-1 production in human dermal fibroblasts. More importantly, propolis treatment reduced UV-induced MMP-1 expression and blocked collagen degradation in human skin tissues, suggesting that the anti-skin-aging activity of propolis can be recapitulated in clinically relevant conditions. While propolis treatment did not display any noticeable effects against extracellular signal-regulated kinase (ERK), p38, and c-jun N-terminal kinase (JNK) pathways, propolis exerted significant inhibitory activity specifically against phosphorylations of phosphoinositide-dependent protein kinase-1 (PDK1) and protein kinase B (Akt). Kinase assay results demonstrated that propolis can directly suppress phosphoinositide 3-kinase (PI3K) activity, with preferential selectivity towards PI3K with p110α and p110δ catalytic subunits over other kinases. The content of active compounds was quantified, and among the compounds identified from the propolis extract, caffeic acid phenethyl ester, quercetin, and apigenin were shown to attenuate PI3K activity. These results demonstrate that propolis shows anti-skin-aging effects through direct inhibition of PI3K activity.

scholarly journals ADP-Mediated Upregulation of Expression of CD62P on Human Platelets Is Critically Dependent on Co-Activation of P2Y1 and P2Y12 Receptors

2020 ◽  
Vol 13 (12) ◽  
pp. 420
Author(s):  
Ronald Anderson ◽  
Annette J. Theron ◽  
Helen C. Steel ◽  
Jan G. Nel ◽  
Gregory R. Tintinger
Keyword(s):  
Flow Cytometry ◽  
Platelet Rich Plasma ◽  
Receptor Activation ◽  
Human Platelets ◽  
P2y12 Receptor ◽  
Phosphatidylinositol 3 Kinase ◽  
Pi3k Activity ◽  
Potent Inhibition ◽  
Co Activation ◽  
Adult Humans

This study probed the differential utilization of P2Y1 and P2Y12 receptors in mobilizing CD62P (P-selectin) from intracellular granules following activation of human platelets with adenosine 5′-diphosphate (ADP, 100 µmol·L−1) Platelet-rich plasma (PRP) was prepared from the blood of adult humans. CD62P was measured by flow cytometry following activation of PRP with ADP in the absence and presence of the selective antagonists of P2Y1 and P2Y12 receptors, MRS2500 and PSB0739 (both 0.155–10 µmol·L−1), respectively. Effects of the test agents on ADP-activated, CD62P-dependent formation of neutrophil:platelet (NP) aggregates were also measured by flow cytometry, while phosphatidylinositol 3-kinase (PI3K) activity was measured according to Akt1 phosphorylation in platelet lysates. Treatment with MRS2500 or PSB0739 at 10 µmol·L−1 almost completely attenuated (94.6% and 86% inhibition, respectively) ADP-activated expression of CD62P and also inhibited NP aggregate formation. To probe the mechanisms involved in P2Y1/P2Y12 receptor-mediated expression of CD62P, PRP was pre-treated with U73122 (phospholipase C (PLC) inhibitor), 2-aminoethoxy-diphenyl borate (2-APB, inositol triphosphate receptor antagonist), calmidazolium chloride (calmodulin inhibitor), or wortmannin (PI3K inhibitor). U73122, 2-APB, and wortmannin caused almost complete inhibition of ADP-activated expression of CD62P, while calmidazolium chloride caused statistically significant, partial inhibition. PSB0739, but not MRS2500, caused potent inhibition of PI3K-mediated phosphorylation of Akt1. Optimal mobilization of CD62P by ADP-stimulated platelets is critically dependent on the co-activation of platelet P2Y1 and P2Y12 receptors. P2Y12 receptor activation is the key event in activation of PI3K, while activation of the P2Y1 receptor appears to create a high cytosolic Ca2+ environment conducive to optimum PI3K activity.

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