124. Regulation of SOCS3 expression by prostaglandin, prolactin and growth hormone: challenging the Jak/STAT signalling dogma

2005 ◽  
Vol 17 (9) ◽  
pp. 74
Author(s):  
J. L. Barclay ◽  
T. Wonisch ◽  
S. T. Anderson ◽  
M. J. Waters ◽  
J. D. Curlewis
Keyword(s):  
Fold Increase ◽  
Signalling Pathways ◽  
Akt Inhibitor ◽  
Akt Phosphorylation ◽  
Jak2 Inhibitor ◽  
Receptor Signalling ◽  
Socs3 Expression ◽  
Cellular Responsiveness ◽  
Responsive Element ◽  
Socs3 Mrna

SOCS3 is an inhibitor of various cytokine-receptor signalling pathways and is therefore involved in suppression of cellular responsiveness to these critical regulators. SOCS3 expression is thought to be regulated by a STAT responsive element (SRE). However, our research suggests the involvement of other signalling pathways. In T-47D breast cancer cells, we found that PGE2 induces a 3–5 fold increase in SOCS3 mRNA, as determined by real-time PCR. This effect was not due to phosphorylation of STATs, or inhibited by the Jak2 inhibitor, AG490, but was inhibited by the PI3Kinase inhibitor, LY294002, Akt Inhibitor IV and partially inhibited by the PKA inhibitor, H89. It was not affected by inhibitors of MEK, PDK1, mTOR or p38-MAPK. We concurrently examined PRL-induced SOCS3 expression, and found that although STAT1 and 5 phosphorylation was increased, SOCS3 expression was again inhibited by Akt Inhibitor IV and H89 but unaffected by AG-490. To explore this further, we used a model of GH signalling, BaF3 cells stably expressing GH receptor. GH induced a 15–20 fold increase in SOCS3 mRNA, which was accompanied by increased STAT5 phosphorylation. However the SOCS3 response was not inhibited by AG-490 or H89, but was diminished by Akt Inhibitor IV. Analysis of the SOCS3 promoter revealed a FOXO binding site. When we mutated this site in a mouse SOCS3 promoter–luciferase construct, basal and GH-induced promoter activity was significantly increased. These results are consistent with FOXO acting as a repressor, which is inactivated by Akt. We propose that in T-47D cells, SOCS3 expression involves cross-talk between PI3K/Akt and cAMP/PKA, whereas in BaF3 cells, expression is enhanced by Akt phosphorylation and subsequent FOXO inactivation. These findings contrast with the accepted Jak/STAT regulation of SOCS3 expression. This work is supported by the Australian Research Council.

scholarly journals ADAM10 and ADAM17 regulate EGFR, c-Met and TNF RI signalling in liver regeneration and fibrosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Olga Zbodakova ◽  
Karel Chalupsky ◽  
Lenka Sarnova ◽  
Petr Kasparek ◽  
Marketa Jirouskova ◽  
...  
Keyword(s):  
Liver Regeneration ◽  
Signalling Pathways ◽  
Substrate Specificities ◽  
Akt Phosphorylation ◽  
Receptor Signalling ◽  
Cellular Context ◽  
Per Se ◽  
Deficient Mice ◽  
Combined Deficiency ◽  
Severe Fibrosis

AbstractADAM10 and ADAM17 are proteases that affect multiple signalling pathways by releasing molecules from the cell surface. As their substrate specificities partially overlaps, we investigated their concurrent role in liver regeneration and fibrosis, using three liver-specific deficient mouse lines: ADAM10- and ADAM17-deficient lines, and a line deficient for both proteases. In the model of partial hepatectomy, double deficient mice exhibited decreased AKT phosphorylation, decreased release of EGFR activating factors and lower shedding of HGF receptor c-Met. Thus, simultaneous ablation of ADAM10 and ADAM17 resulted in inhibited EGFR signalling, while HGF/c-Met signalling pathway was enhanced. In contrast, antagonistic effects of ADAM10 and ADAM17 were observed in the model of chronic CCl4 intoxication. While ADAM10-deficient mice develop more severe fibrosis manifested by high ALT, AST, ALP and higher collagen deposition, combined deficiency of ADAM10 and ADAM17 surprisingly results in comparable degree of liver damage as in control littermates. Therefore, ADAM17 deficiency is not protective in fibrosis development per se, but can ameliorate the damaging effect of ADAM10 deficiency on liver fibrosis development. Furthermore, we show that while ablation of ADAM17 resulted in decreased shedding of TNF RI, ADAM10 deficiency leads to increased levels of soluble TNF RI in serum. In conclusion, hepatocyte-derived ADAM10 and ADAM17 are important regulators of growth receptor signalling and TNF RI release, and pathological roles of these proteases are dependent on the cellular context.

scholarly journals ADAM10 and ADAM17 in Liver Regeneration and Fibrosis: Regulation of EGFR, c-Met and TNF RI Signalling

2021 ◽  
Author(s):  
Olga Zbodakova ◽  
Karel Chalupsky ◽  
Lenka Sarnova ◽  
Petr Kasparek ◽  
Marketa Jirouskova ◽  
...  
Keyword(s):  
Liver Regeneration ◽  
Signalling Pathways ◽  
Substrate Specificities ◽  
Akt Phosphorylation ◽  
Receptor Signalling ◽  
Cellular Context ◽  
Per Se ◽  
Deficient Mice ◽  
Combined Deficiency ◽  
Severe Fibrosis

Abstract ADAM10 and ADAM17 are proteases that affect multiple signalling pathways by releasing molecules from the cell surface. As their substrate specificities partially overlaps, we investigated their concurrent role in liver regeneration and fibrosis, using three liver-specific deficient mouse lines: ADAM10- and ADAM17-deficient lines, and a line deficient for both proteases. In the model of partial hepatectomy, double deficient mice exhibited decreased AKT phosphorylation, decreased release of EGFR activating factors and lower shedding of HGF receptor c-Met. Thus, simultaneous ablation of ADAM10 and ADAM17 resulted in impaired EGFR signalling, while HGF/c-Met signalling pathway was enhanced. In contrast, antagonistic effects of ADAM10 and ADAM17 were observed in the model of chronic CCl4 intoxication. While ADAM10-deficient mice develop more severe fibrosis manifested by high ALT, AST, ALP and higher collagen deposition, combined deficiency of ADAM10 and ADAM17 surprisingly results in comparable degree of liver damage as in control littermates. Therefore, ADAM17 deficiency is not protective in fibrosis development per se, but can ameliorate the damaging effect of ADAM10 deficiency on liver fibrosis development and results in decreased shedding of TNF RI, while ADAM10 deficiency leads to increased levels of soluble TNF RI in serum. In conclusion, hepatocyte-derived ADAM10 and ADAM17 are important regulators of growth receptor signalling and TNF RI release, and pathological roles of these proteases are dependent on the cellular context.

scholarly journals Combined Application of Pan-AKT Inhibitor MK-2206 and BCL-2 Antagonist Venetoclax in B-Cell Precursor Acute Lymphoblastic Leukemia

2021 ◽  
Vol 22 (5) ◽  
pp. 2771
Author(s):  
Anna Richter ◽  
Elisabeth Fischer ◽  
Clemens Holz ◽  
Julia Schulze ◽  
Sandra Lange ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tumor Cell ◽  
Cell Lines ◽  
Morphological Changes ◽  
Synergistic Effects ◽  
Lymphoblastic Leukemia ◽  
Tumor Cell Proliferation ◽  
Akt Inhibitor ◽  
Akt Phosphorylation ◽  
Combined Application

Aberrant PI3K/AKT signaling is a hallmark of acute B-lymphoblastic leukemia (B-ALL) resulting in increased tumor cell proliferation and apoptosis deficiency. While previous AKT inhibitors struggled with selectivity, MK-2206 promises meticulous pan-AKT targeting with proven anti-tumor activity. We herein, characterize the effect of MK-2206 on B-ALL cell lines and primary samples and investigate potential synergistic effects with BCL-2 inhibitor venetoclax to overcome limitations in apoptosis induction. MK-2206 incubation reduced AKT phosphorylation and influenced downstream signaling activity. Interestingly, after MK-2206 mono application tumor cell proliferation and metabolic activity were diminished significantly independently of basal AKT phosphorylation. Morphological changes but no induction of apoptosis was detected in the observed cell lines. In contrast, primary samples cultivated in a protective microenvironment showed a decrease in vital cells. Combined MK-2206 and venetoclax incubation resulted in partially synergistic anti-proliferative effects independently of application sequence in SEM and RS4;11 cell lines. Venetoclax-mediated apoptosis was not intensified by addition of MK-2206. Functional assessment of BCL-2 inhibition via Bax translocation assay revealed slightly increased pro-apoptotic signaling after combined MK-2206 and venetoclax incubation. In summary, we demonstrate that the pan-AKT inhibitor MK-2206 potently blocks B-ALL cell proliferation and for the first time characterize the synergistic effect of combined MK-2206 and venetoclax treatment in B-ALL.

An IRP-like protein from Plasmodium falciparum binds to a mammalian iron-responsive element

Blood ◽  
2001 ◽  
Vol 98 (8) ◽  
pp. 2555-2562 ◽  
Author(s):  
Mark Loyevsky ◽  
Timothy LaVaute ◽  
Charles R. Allerson ◽  
Robert Stearman ◽  
Olakunle O. Kassim ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Regulatory Protein ◽  
Protein S ◽  
Fold Increase ◽  
Binding Activity ◽  
Mobility Shift ◽  
Iron Responsive Element ◽  
Element Binding Protein ◽  
Responsive Element ◽  
Electrophoretic Mobility Shift Assays

Abstract This study cloned and sequenced the complementary DNA (cDNA) encoding of a putative malarial iron responsive element-binding protein (PfIRPa) and confirmed its identity to the previously identified iron-regulatory protein (IRP)–like cDNA from Plasmodium falciparum. Sequence alignment showed that the plasmodial sequence has 47% identity with human IRP1. Hemoglobin-free lysates obtained from erythrocyte-stage P falciparum contain a protein that binds a consensus mammalian iron-responsive element (IRE), indicating that a protein(s) with iron-regulatory activity was present in the lysates. IRE-binding activity was found to be iron regulated in the electrophoretic mobility shift assays. Western blot analysis showed a 2-fold increase in the level of PfIRPa in the desferrioxamine-treated cultures versus control or iron-supplemented cells. Malarial IRP was detected by anti-PfIRPa antibody in the IRE-protein complex fromP falciparum lysates. Immunofluorescence studies confirmed the presence of PfIRPa in the infected red blood cells. These findings demonstrate that erythrocyte P falciparum contains an iron-regulated IRP that binds a mammalian consensus IRE sequence, raising the possibility that the malaria parasite expresses transcripts that contain IREs and are iron-dependently regulated.

Lyn kinase plays important roles in erythroid expansion, maturation and erythropoietin receptor signalling by regulating inhibitory signalling pathways that control survival

2014 ◽  
Vol 459 (3) ◽  
pp. 455-466 ◽  
Author(s):  
Neli S. Slavova-Azmanova ◽  
Nicole Kucera ◽  
Alison Louw ◽  
Jiulia Satiaputra ◽  
Adley Handoko ◽  
...  
Keyword(s):  
Cell Survival ◽  
Cell Development ◽  
Erythropoietin Receptor ◽  
Erythroid Cell ◽  
Signalling Pathways ◽  
Erythroid Cells ◽  
Src Family Kinase ◽  
Receptor Signalling ◽  
Lyn Kinase ◽  
Control Survival

In erythroid cells both positive viability signals and feedback inhibitory signalling require the Src family kinase Lyn, influencing cell survival and their ability to differentiate. This illustrates that Lyn is critical for normal erythropoiesis and erythroid cell development.

scholarly journals Monophosphoryl lipid A induces protection against LPS in medullary thick ascending limb through a TLR4-TRIF-PI3K signaling pathway

2017 ◽  
Vol 313 (1) ◽  
pp. F103-F115 ◽  
Author(s):  
Bruns A. Watts ◽  
Thampi George ◽  
Edward R. Sherwood ◽  
David W. Good
Keyword(s):  
Bacterial Infections ◽  
Lipid A ◽  
Thick Ascending Limb ◽  
Akt Inhibitor ◽  
Erk Activation ◽  
Akt Phosphorylation ◽  
Medullary Thick Ascending Limb ◽  
Monophosphoryl Lipid A ◽  
Monophosphoryl Lipid

Monophosphoryl lipid A (MPLA) is a detoxified derivative of LPS that induces tolerance to LPS and augments host resistance to bacterial infections. Previously, we demonstrated that LPS inhibits [Formula: see text] absorption in the medullary thick ascending limb (MTAL) through a basolateral Toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88)-ERK pathway. Here we examined whether pretreatment with MPLA would attenuate LPS inhibition. MTALs from rats were perfused in vitro with MPLA (1 µg/ml) in bath and lumen or bath alone for 2 h, and then LPS was added to (and MPLA removed from) the bath solution. Pretreatment with MPLA eliminated LPS-induced inhibition of [Formula: see text] absorption. In MTALs pretreated with MPLA plus a phosphatidylinositol 3-kinase (PI3K) or Akt inhibitor, LPS decreased [Formula: see text] absorption. MPLA increased Akt phosphorylation in dissected MTALs. The Akt activation was eliminated by a PI3K inhibitor and in MTALs from TLR4−/−or Toll/IL-1 receptor domain-containing adaptor-inducing IFN-β (TRIF)−/−mice. The effect of MPLA to prevent LPS inhibition of [Formula: see text] absorption also was TRIF dependent. Pretreatment with MPLA prevented LPS-induced ERK activation; this effect was dependent on PI3K. MPLA alone had no effect on [Formula: see text] absorption, and MPLA pretreatment did not prevent ERK-mediated inhibition of [Formula: see text] absorption by aldosterone, consistent with MPLA's low toxicity profile. These results demonstrate that pretreatment with MPLA prevents the effect of LPS to inhibit [Formula: see text] absorption in the MTAL. This protective effect is mediated directly through MPLA stimulation of a TLR4-TRIF-PI3K-Akt pathway that prevents LPS-induced ERK activation. These studies identify detoxified TLR4-based immunomodulators as novel potential therapeutic agents to prevent or treat renal tubule dysfunction in response to bacterial infections.

scholarly journals oxLDL induces endothelial cell proliferation via Rho/ROCK/Akt/p27kip1 signaling: opposite effects of oxLDL and cholesterol loading

2017 ◽  
Vol 313 (3) ◽  
pp. C340-C351 ◽  
Author(s):  
Chongxu Zhang ◽  
Crystal Adamos ◽  
Myung-Jin Oh ◽  
Jugajyoti Baruah ◽  
Manuela A. A. Ayee ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Kinase Inhibitor ◽  
Oxidized Ldl ◽  
Endothelial Cell Proliferation ◽  
Dependent Manner ◽  
Akt Inhibitor ◽  
Aortic Endothelial Cells ◽  
Akt Phosphorylation ◽  
Downstream Target ◽  
Underlying Mechanisms

Oxidized modifications of LDL (oxLDL) play a key role in the development of endothelial dysfunction and atherosclerosis. However, the underlying mechanisms of oxLDL-mediated cellular behavior are not completely understood. Here, we compared the effects of two major types of oxLDL, copper-oxidized LDL (Cu2+-oxLDL) and lipoxygenase-oxidized LDL (LPO-oxLDL), on proliferation of human aortic endothelial cells (HAECs). Cu2+-oxLDL enhanced HAECs’ proliferation in a dose- and degree of oxidation-dependent manner. Similarly, LPO-oxLDL also enhanced HAEC proliferation. Mechanistically, both Cu2+-oxLDL and LPO-oxLDL enhance HAEC proliferation via activation of Rho, Akt phosphorylation, and a decrease in the expression of cyclin-dependent kinase inhibitor 1B (p27kip1). Both Cu2+-oxLDL or LPO-oxLDL significantly increased Akt phosphorylation, whereas an Akt inhibitor, MK2206, blocked oxLDL-induced increase in HAEC proliferation. Blocking Rho with C3 or its downstream target ROCK with Y27632 significantly inhibited oxLDL-induced Akt phosphorylation and proliferation mediated by both Cu2+- and LPO-oxLDL. Activation of RhoA was blocked by Rho-GDI-1, which also abrogated oxLDL-induced Akt phosphorylation and HAEC proliferation. In contrast, blocking Rac1 in these cells had no effect on oxLDL-induced Akt phosphorylation or cell proliferation. Moreover, oxLDL-induced Rho/Akt signaling downregulated cell cycle inhibitor p27kip1. Preloading these cells with cholesterol, however, prevented oxLDL-induced Akt phosphorylation and HAEC proliferation. These findings provide a new understanding of the effects of oxLDL on endothelial proliferation, which is essential for developing new treatments against neovascularization and progression of atherosclerosis.

Abstract P125: A Novel Role for Survivin in Insulin-induced Inhibition of Myocardial Apoptosis in Ischemic/reperfused Heart

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Rui Si ◽  
Qiujun Yu ◽  
Ning Zhou ◽  
Ling Tao ◽  
Wenyi Guo ◽  
...  
Keyword(s):  
Ischemia Reperfusion ◽  
Specific Inhibitor ◽  
Survivin Expression ◽  
Fold Increase ◽  
Tunel Staining ◽  
Sprague Dawley ◽  
Signaling Mechanism ◽  
Akt Phosphorylation ◽  
Apoptotic Effect

Objectives: Insulin reduces post-ischemic myocardial apoptotic death, but the mechanism remains unclear. Survivin, an anti-apoptotic protein has recently found participating in vascular repair. This study aimed to test the hypothesis that the up-regulation of survivin by insulin may play a role in the antiapoptotic and cardioprotective effects in the ischemic/reperfused (I/R) heart, and further investigate the signaling mechanism involved. Methods : Isolated adult Sprague-Dawley rat hearts were subjected to 30 min regional ischemia and 3 h of reperfusion. The hearts were randomized to receive insulin, insulin plus LY294002 (specific inhibitor of PI3K), or insulin plus rapamycin (specific inhibitor of mTOR) at the start of reperfusion. To further confirm the correlation between survivin and myocardial survival in vitro, cardiomyocytes were infected with adenovirus encoding survivin or transfected with siRNA targeting survivin. Phosphorylation of Akt, mTOR, p70S6K and the expression of protein survivin were determined and infarct size was assessed using TTC staining, cardiomyocytes apoptosis were evaluated after reperfusion by TUNEL staining and DNA laddering. Results: I/R increased myocardial survivin expression. Insulin reperfusion (10 −7 mol/L) resulted in a 4.2-fold increase in survivin expression (P<0.01 vs. I/R alone), which was almost completely blocked by LY294002. Both of the mTOR phosphorylation and survivin expression were inhibited in the group of insulin reperfusion plus LY294002. Rapamycin reperfusion did not change Akt phosphorylation but partially inhibited survivin expression (16.7±1.2 vs. 9.8±1.6, P<0.01 vs. I/R+Ins), which indicated a cardioprotective effect of survivin and a possible PI3K/Akt/mTOR/SVV signaling pathway during I/R. Moreover, over-expressed survivin provides protection against stimulated ischemia reperfusion induced cardiomyocyte apoptosis, while targeting survivin blunted the anti-apoptotic effect of insulin. Conclusion: This study demonstrates that insulin up-regulates myocardial survivin expression, partly at least, via PI3-kinase-mTOR mechanism, which contributes to the anti-apoptotic effect of insulin in the I/R heart.

Mesoderm-inducing properties of INT-2 and kFGF: two oncogene-encoded growth factors related to FGF

Development ◽  
1989 ◽  
Vol 106 (1) ◽  
pp. 79-83 ◽  
Author(s):  
G.D. Paterno ◽  
L.L. Gillespie ◽  
M.S. Dixon ◽  
J.M. Slack ◽  
J.K. Heath
Keyword(s):  
Growth Factors ◽  
Embryonic Development ◽  
Xenopus Laevis ◽  
Dna Synthesis ◽  
Signalling Pathways ◽  
Control Mechanisms ◽  
Animal Pole ◽  
Receptor Signalling ◽  
Mammalian Embryogenesis ◽  
Mesoderm Formation

Many theories of neoplasia suggest that oncogenic transformations result from aberrations in the control mechanisms which normally regulate growth and differentiation during embryonic development. It has recently become clear that many proto-oncogenes are differentially expressed during embryonic development and may thus be important embryonic regulatory molecules. We report here that the products of two transforming oncogenes int-2 and hst/ks (now called kfgf) can, with different potencies, induce mesoderm formation in isolated Xenopus laevis animal pole explants and stimulate DNA synthesis in mammalian fibroblasts. The results suggest that these proteins may function as mesoderm inducers in mammalian embryogenesis and that similar receptor/signalling pathways may be utilized for developmental and oncogenic processes. Finally, we have shown that the Xenopus assay system used in this study provides a powerful screen for protein factors that are active in development.

Sign in / Sign up

Export Citation Format

Share Document