Prostaglandin E2 Inhibits Human Lung Fibroblast Chemotaxis through Disparate Actions on Different E-Prostanoid Receptors. Li YJ, Wang XQ, Sato T, Kanaji N, Nakanishi M, Kim M, Michalski J, Nelson AJ, Sun JH, Farid M, Basma H, Patil A, Toews ML, Liu X, Rennard SI Am J Respir Cell Mol Biol
2010
Show Abstract
Migration of fibroblasts is believed to play a key role in both normal wound repair and in abnormal tissue remodeling. Prostaglandin E (PGE)2 is a mediator that can inhibit many fibroblast functions including chemotaxis, which has been reported to be mediated by the E Prostanoid (EP) receptor EP2. PGE2, however, can act on four receptors. The current study, therefore, was designed to determine if EP receptors in addition to EP2 can modulate fibroblast chemotaxis. Using human fetal lung fibroblasts (HFL-1), expression of all four EP receptors was demonstrated by western blot. EP2- and EP4-selective agonists inhibited both chemotaxis toward fibronectin in the blindwell assay and migration in a wound closure assay. In contrast, EP1- and EP3-selective agonists stimulated in both assay systems. These results were confirmed using EP-selective antagonists. The role of both EP2 and EP4 receptors in mediating PGE2 inhibition of chemotaxis was also confirmed with siRNA suppression. Finally, the role of the EP receptors was further confirmed by blocking the expected signaling pathways. Taken together, these results demonstrate that PGE2 can act on multiple EP receptors in human lung fibroblasts that can have disparate effects. Alterations in EP receptor expression would have the potential to alter PGE2 action. Targeting of specific EP receptors may offer therapeutic opportunity for conditions characterized by abnormal tissue repair and remodeling. | | 20203295
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Cyclin-dependent kinase 5 regulates endothelial cell migration and angiogenesis. Johanna Liebl,Sabine B Weitensteiner,György Vereb,Lili Takács,Robert Fürst,Angelika M Vollmar,Stefan Zahler The Journal of biological chemistry
285
2010
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Angiogenesis contributes to various pathological conditions. Due to the resistance against existing antiangiogenic therapy, an urgent need exists to understand the molecular basis of vessel growth and to identify new targets for antiangiogenic therapy. Here we show that cyclin-dependent kinase 5 (Cdk5), an important modulator of neuronal processes, regulates endothelial cell migration and angiogenesis, suggesting Cdk5 as a novel target for antiangiogenic therapy. Inhibition or knockdown of Cdk5 reduces endothelial cell motility and blocks angiogenesis in vitro and in vivo. We elucidate a specific signaling of Cdk5 in the endothelium; in contrast to neuronal cells, the motile defects upon inhibition of Cdk5 are not caused by an impaired function of focal adhesions or microtubules but by the reduced formation of lamellipodia. Inhibition or down-regulation of Cdk5 decreases the activity of the small GTPase Rac1 and results in a disorganized actin cytoskeleton. Constitutive active Rac1 compensates for the inhibiting effects of Cdk5 knockdown on migration, suggesting that Cdk5 exerts its effects in endothelial cell migration via Rac1. Our work elucidates Cdk5 as a pivotal new regulator of endothelial cell migration and angiogenesis. It suggests Cdk5 as a novel, pharmacologically accessible target for antiangiogenic therapy and provides the basis for a new therapeutic application of Cdk5 inhibitors as antiangiogenic agents. Full Text Article | | 20826806
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Attenuation of angiotensin II-induced hypertension and cardiac hypertrophy in transgenic mice overexpressing a type 1 receptor mutant. Saad Ahmad,Francesca Cesana,Edward Lamperti,Haralambos Gavras,Jun Yu American journal of hypertension
22
2009
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The angiotensin II (AngII) type 1 receptor (AT1) regulates cardiovascular function by activating various signal pathways. The purpose of this study was to evaluate the effects of a mutant AT1 receptor on AngII-responding blood pressure and cardiac hypertrophy in conjunction with altered AngII activation of RhoA and Akt. Full Text Article | | 19779471
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Pulmonary microvascular endothelial cells form a tighter monolayer when grown in chronic hypoxia. Victor Solodushko, James C Parker, Brian Fouty American journal of respiratory cell and molecular biology
38
491-7
2008
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Unique among the vascular beds, loss of endothelial integrity in the pulmonary microcirculation due to injury can lead to rapidly fatal hypoxemia. The ability to regain confluence and re-establish barrier function is central to restoring proper gas exchange. The adult respiratory distress syndrome (ARDS) is a heterogeneous disease, however, meaning that endothelial cells within different regions of the lung do not likely see the same oxygen tension as they attempt to proliferate and re-establish an intact endothelial monolayer; the effect of hypoxia on the integrity of this newly formed endothelial monolayer is not clear. Immortalized human pulmonary microvascular endothelial cells (PMVEC) (ST1.6R cells) were sparsely plated and grown to confluence over 4 days in either normoxia (21% oxygen) or hypoxia (5% oxygen). Confluence attained in a hypoxic environment resulted in a tighter, less permeable endothelial monolayer (as determined by an increase in transendothelial electrical resistance, decreased permeability to fluorescently labeled macromolecules, and decreased hydraulic conductance). PMVEC grown to confluence under hypoxia had decreased RhoA activity; consistent with this finding, inhibition of Rho kinase, a well-described downstream target of RhoA, markedly increased electrical resistance in normoxic, but not hypoxic, PMVEC. These results were confirmed in primary human and rat PMVEC. These data suggest that PMVEC grown to confluence under hypoxia form a tighter monolayer than similar cells grown under normoxia. This tighter barrier appears to be due, in part, to the inhibition of RhoA activity in hypoxic cells. Full Text Article | | 18048805
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Sphingosine 1-phosphate potentiates human lung fibroblast chemotaxis through the S1P2 receptor. Mitsu Hashimoto, Xingqi Wang, Lijun Mao, Tetsu Kobayashi, Shin Kawasaki, Naoyoshi Mori, Myron L Toews, Hui Jung Kim, D Roselyn Cerutis, Xiangde Liu, Stephen I Rennard American journal of respiratory cell and molecular biology
39
356-63
2008
Show Abstract
Migration of fibroblasts plays an essential role in tissue repair after injury. Sphingosine 1-phosphate (S1P) is a multifunctional mediator released by many cells that can be released in inflammation and after injury. This study evaluated the effect of S1P on fibroblast chemotaxis toward fibronectin. S1P alone did not affect fibroblast migration, but S1P enhanced fibronectin-directed chemotaxis in a concentration-dependent manner. The effect of S1P was not mimicked by dihydro (dh) S1P or the S1P(1) receptor agonist SEW2871. S1P augmentation of fibroblast chemotaxis, however, was completely blocked by JTE-013, an S1P(2) antagonist, but not by suramin, an S1P(3) antagonist. Suppression of the S1P(2) receptor by small interfering (si)RNA also completely blocked S1P augmentation of fibroblast chemotaxis to fibronectin. S1P stimulated Rho activation and focal adhesion kinase (FAK) phosphorylation, and these were also significantly inhibited by the S1P(2) receptor antagonist (JTE-013) or by S1P(2) siRNA. Further, the potentiation of S1P signaling was blocked by the Rho-kinase inhibitor Y-27632 in a concentration-dependent manner. Inhibition of FAK with siRNA reduced basal chemotaxis toward fibronectin slightly but significantly, and almost completely blocked S1P augmented chemotaxis. These results suggest that S1P-augmented fibroblast chemotaxis toward fibronectin depends on the S1P(2) receptor and requires Rho and Rho-kinase, and FAK phosphorylation. By augmenting fibroblast recruitment, S1P has the potential to modulate tissue repair after injury. The pathways by which S1P mediates this effect, therefore, represent a potential therapeutic target to affect tissue repair and remodeling. Full Text Article | | 18367729
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Atorvastatin decreases lipoprotein lipase and endothelial lipase expression in human THP-1 macrophages. Guosong Qiu, John S Hill Journal of lipid research
48
2112-22
2007
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Macrophage-derived lipases are associated with atherosclerosis in human and animal studies. Despite numerous non-lipid-lowering effects of statins, their effect on macrophage LPL and endothelial lipase (EL) expression has not been investigated. In the present study, atorvastatin and simvastatin dose-dependently decreased LPL and EL expression as well as Rho, liver X receptor alpha (LXRalpha), and nuclear factor kappaB (NF-kappaB) activation in THP-1 macrophages. Atorvastatin-reduced LPL and EL expression was only partially recovered by mevalonate cotreatment, indicating that mechanisms independent of reductase inhibition may be present. By contrast, Rho activation by lysophosphatidyl acid further decreased LPL and EL expression in the presence or absence of atorvastatin. Another Rho activator, farnysyl pyrophosphate, decreased EL expression only in the absence of atorvastatin. LXRalpha activation by T0901317 and 22(R)-hydroxycholesterol not only rescued but also significantly increased LPL expression in the presence and absence of atorvastatin, respectively, whereas LXRalpha inhibition by 22(S)-hydroxycholesterol decreased LPL expression. By contrast, EL expression was suppressed by LXRalpha activation in the presence or absence of atorvastatin. NF-kappaB inhibition by SN50 was associated with an approximately 30% reduction of EL expression. Furthermore, atorvastatin treatment significantly attenuated the lipid accumulation in macrophages treated with oxidized LDL. We conclude that atorvastatin reduces LPL and EL expression by reducing the activation of LXRalpha and NF-kappaB, respectively. | | 17644777
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Rho signalling at a glance. Schwartz, Martin J. Cell. Sci., 117: 5457-8 (2004)
2004
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Protein kinase A-mediated phosphorylation of the Galpha13 switch I region alters the Galphabetagamma13-G protein-coupled receptor complex and inhibits Rho activation Manganello, J. M., et al J Biol Chem, 278:124-30 (2003)
2003
| Activation Assay | 12399457
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Tumor suppressor p53 and its homologue p73alpha affect cell migration. Sablina, Anna A, et al. J. Biol. Chem., 278: 27362-71 (2003)
2003
Show Abstract
The p53 tumor suppressor plays a central role in the negative control of growth and survival of abnormal cells. Previously we demonstrated that in addition to these functions, p53 expression affects cell morphology and lamellar activity of the cell edge (Alexandrova, A., Ivanov, A., Chumakov, P. M., Kopnin, P. B., and Vasiliev, J. M. (2000) Oncogene 19, 5826-5830). In the present work we studied the effects of p53 and its homologue p73alpha on cell migration. We found that loss of p53 function correlated with decreased cell migration that was analyzed by in vitro wound closure test and Boyden chamber assay. The decreased motility of p53-deficient cells was observed in different cell contexts: human foreskin fibroblasts (BJ), human colon and lung carcinoma cell lines (HCT116 and H1299, respectively), as well as mouse normal fibroblasts from lung and spleen, peritoneal macrophages, and keratinocytes. On the other hand, overexpression of the p53 family member p73alpha stimulated cell migration. Changes in cell migration correlated directly with transcription activation induced by p53 or p73alpha. Noteworthy, p53 modulated cell motility in the absence of stress. The effect of p53 and p73alpha on cell migration was mediated through the activity of the phosphatidylinositol 3-kinase/Rac1 pathway. This p53/p73 function was mainly associated with some modulation of intracellular signaling rather than with stimulation of production of secreted motogenic factors. The identified novel activity of the p53 family members might be involved in regulation of embryogenesis, wound healing, or inflammatory response. | Activation Assay | 12750388
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Protein kinase involved in lung injury susceptibility: Evidence from enzyme isoform genetic knockout and in vivo inhibitor treatment Wainwright, M. S., et al Proc Natl Acad Sci U S A, 100:6233-8 (2003)
2003
| Activation Assay | 12730364
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