Nitric oxide (NO) seems to play a pivotal role in the vascular endothelial growth factor (VEGF)-induced endothelial cell proliferation. This study was designed to investigate the role and intracellular signal pathway of endothelial nitric oxide synthase (eNOS) activation induced by VEGF. ECV 304 cells were treated with betaVEGF(165) and then cell proliferation, eNOS protein and mRNA expression levels were analyzed to elucidate the functional role of eNOS in cell proliferation induced by VEGF. After exposure of cells to betaVEGF(165) , eNOS activity and cell growth were increased by approximately two-fold in the betaVEGF(165) -treated cells compared to the untreated cells. In addition, VEGF stimulated eNOS expression at both the mRNA and protein levels in a dose-dependent manner. Phosphatidylinositol-3 kinase (PI-3K) inhibitors were used to assess PI-3K involvement in eNOS regulation. LY294002 was found to attenuate VEGF-stimulated eNOS expression. Wortmannin was not as effective as LY294002, but the reduction effect was detectable. Cells activated by VEGF showed increased ERK1/2 levels. Moreover, the VEGF-induced eNOS expression was reduced by the PD98059, MAPK pathway inhibitor. This suggests that eNOS expression might be regulated by PI-3K and the ERK1/2 signaling pathway. In conclusion, betaVEGF(165) induces ECV 304 cell proliferation via the NO produced by eNOS. In addition, eNOS may be regulated by the PI-3K or mitogen-activated protein kinase pathway.
1-Phosphatidylinositol 3-Kinase/*antagonists & inhibitors ; Cell Division/drug effects ; Cell Line ; Endothelial Growth Factors/*metabolism/pharmacology ; Endothelium, Vascular/cytology ; *Gene Expression Regulation, Enzymologic ; Lymphokines/*metabolism/pharmacology ; MAP Kinase Signaling System ; Mitogen-Activated Protein Kinase 1/*antagonists & inhibitors ; Mitogen-Activated Protein Kinase 3 ; Mitogen-Activated Protein Kinases/*antagonists & inhibitors ; Nitric Oxide Synthase/*genetics/metabolism ; Nitric Oxide Synthase Type III ; Signal Transduction ; Vascular Endothelial Growth Factor A ; Vascular Endothelial Growth Factors

The expression of hypoxia-inducible factor (HIF) is influenced by reactive oxygen species (ROS). Effect of bilirubin on HIF-1 expression in proximal tubular cells was investigated under physiological oxygen concentration, which is relative hypoxic condition mimicking oxygen content in the medulla of renal tissue. The human kidney (HK2) cells were cultured in 5% oxygen with or without bilirubin. HIF-1alpha protein expression was increased by bilirubin treatment at 0.01-0.2 mg/dL concentration. The messenger RNA expression of HIF-1alpha was increased by 1.69+/-0.05 folds in the cells cultured with 0.1 mg/dL bilirubin, compared to the control cells. The inhibitors of PI3K/mTOR, PI3K/AKT, and ERK 1/2 pathways did not attenuate increased HIF-1alpha expression by bilirubin. HIF-1alpha expression decreased by 10 microM exogenous hydrogen peroxide (H2O2); scavenger of ROS with or without bilirubin in the HK2 cells increased HIF-1alpha concentration more than that in the cells without bilirubin. Exogenous H2O2 decreased the phosphorylation of P70S6 kinase, which was completely reversed by bilirubin treatment. Knockdown of NOX4 gene by small interfering RNA (siRNA) increased HIF-1alpha mRNA expression. In coonclusion, bilirubin enhances HIF-1alpha transcription as well as the up-regulation of HIF-1alpha protein translation through the attenuation of ROS and subunits of NADPH oxidase.
Bilirubin/*pharmacology ; Cell Line ; Epithelial Cells/cytology/metabolism ; Humans ; Hydrogen Peroxide/toxicity ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics/*metabolism ; Kidney Tubules, Proximal/cytology ; Mitogen-Activated Protein Kinase 1/metabolism ; Mitogen-Activated Protein Kinase 3/metabolism ; NADPH Oxidase/antagonists & inhibitors/genetics/metabolism ; Oxygen/*pharmacology ; Phosphatidylinositol 3-Kinases/metabolism ; Phosphorylation/drug effects ; Proto-Oncogene Proteins c-akt/metabolism ; RNA Interference ; Ribosomal Protein S6 Kinases, 70-kDa/metabolism ; Signal Transduction/drug effects ; TOR Serine-Threonine Kinases/metabolism ; Transcriptional Activation/*drug effects ; Up-Regulation/drug effects

To investigate the role of the extracellular signal-regulated kinase (ERK1/2) and PI3K/AKT/ mTOR signal pathway inducing bone marrow mesenchymal stem cells (BMSCs) differentiation into neural cells, mouse bone marrow-derived mesenchymal stem cell lines D1 cells were used as research object. And they were divided into control groups and salidroside (SD) groups. Different concentrations (5, 25, 50, 100 and 200 microg x mL(-1) of SD were used and SD (100 microg x mL(-1)) was used to induce at different time (0.5, 1, 3, 6, 9, 12, 24, 48 and 72 h). The immunofluorescence staining chemical technology, real-time PCR and Western blotting were used to detect the positive rates of NSE, MAP2, beta-Tubulin III, NES, GFAP and the expression levels of beta-Tubulin III, NSE, ERK1/2, AKT. The expression of ERK1/2 and NSE was detected when the ERK1/2 and PI3K/AKT/ mTOR signal pathway was blocked by PD98059 and LY294002. It indicated that the positive rates of NSE, MAP2, beta-Tubulin III, NES and GFAP were gradually enhanced with time increased. The expression level of NSE and beta-Tubulin III protein were significantly higher than those in control groups (P < 0.01). The expression of ERK1/2, AKT mRNA and protein were higher with concentration and time increased. When the ERK1/2 and PI3K/AKT/mTOR signal pathway were blocked, the expression levels of NSE, NES and beta-Tubulin III mRNA and NSE protein were inhibited significantly. It points out that SD can stimulate the ERK1/2 and PI3K/AKT/mTOR signal pathway to promote BMSCs differentiation into neural cells.
Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Chromones ; pharmacology ; Enzyme Inhibitors ; pharmacology ; Flavonoids ; pharmacology ; Glial Fibrillary Acidic Protein ; metabolism ; Glucosides ; antagonists & inhibitors ; isolation & purification ; pharmacology ; MAP Kinase Signaling System ; drug effects ; Mesenchymal Stromal Cells ; cytology ; Mice ; Microtubule-Associated Proteins ; metabolism ; Mitogen-Activated Protein Kinase 1 ; genetics ; metabolism ; Mitogen-Activated Protein Kinase 3 ; genetics ; metabolism ; Morpholines ; pharmacology ; Nestin ; metabolism ; Neurons ; cytology ; metabolism ; Phenols ; antagonists & inhibitors ; isolation & purification ; pharmacology ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphopyruvate Hydratase ; genetics ; metabolism ; Plants, Medicinal ; chemistry ; Protein Kinase Inhibitors ; pharmacology ; Proto-Oncogene Proteins c-akt ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Rhodiola ; chemistry ; Signal Transduction ; drug effects ; TOR Serine-Threonine Kinases ; metabolism ; Tubulin ; metabolism

Stem cell factor (SCF) is an early-acting cytokine inducing proliferative synergy with other cytokines in hematopoietic cells. We earlier showed that p21 was synergistically induced in SCF synergy and the p44/42 MAPK pathway was essential for the transcriptional control of p21. SCF synergy accompanies protein synthesis. p70S6K implicated in translational control in many other systems has not been shown in SCF synergy induced system. GM-CSF dependent human cell line MO7e was stimulated with GM-CSF with SCF, and investigated activation of p70S6K by using phospho-specific antibody. A possible contribution of p70S6K to SCF synergy was examined by measuring p21 induction as a model system. p70S6K was slightly activated by GM-CSF alone and markedly activated by SCF alone. Combined stimulation with these two cytokines synergistically activated p70S6K resulting in persistent activation. Addition of the pathway- specific inhibitors for PI3K or FRAP/TOR, two upstream pathways of p70S6K resulted in abolishment of p70S6K phosphorylation and also significant reduction of p21 protein level. These data suggest that synergistically activated p70S6K by GM-CSF plus SCF involves, at least in part, protein translational control including regulation of p21 protein.
1-Phosphatidylinositol 3-Kinase/metabolism ; Drug Synergism ; Enzyme Activation ; Granulocyte-Macrophage Colony-Stimulating Factor/*pharmacology ; Hematopoietic Stem Cells/*enzymology ; Human ; Phosphorylation/drug effects ; Protein-Serine-Threonine Kinases/metabolism ; Ribosomal Protein S6 Kinases, 70kD/antagonists & inhibitors/*metabolism ; Stem Cell Factor/*pharmacology ; Tacrolimus Binding Protein 1A/metabolism

Matrix metalloproteinase-9 (MMP-9) may play an important role in emphysematous change in chronic obstructive pulmonary disease (COPD), one of the leading causes of mortality and morbidity worldwide. We previously reported that simvastatin, an inhibitor of HMG-CoA reductase, attenuates emphysematous change and MMP-9 induction in the lungs of rats exposed to cigarette smoke. However, it remained uncertain how cigarette smoke induced MMP-9 and how simvastatin inhibited cigarette smoke-induced MMP-9 expression in alveolar macrophages (AMs), a major source of MMP-9 in the lungs of COPD patients. Presently, we examined the related signaling for MMP-9 induction and the inhibitory mechanism of simvastatin on MMP-9 induction in AMs exposed to cigarette smoke extract (CSE). In isolated rat AMs, CSE induced MMP-9 expression and phosphorylation of ERK and Akt. A chemical inhibitor of MEK1/2 or PI3K reduced phosphorylation of ERK or Akt, respectively, and also inhibited CSE-mediated MMP-9 induction. Simvastatin reduced CSE-mediated MMP-9 induction, and simvastatin-mediated inhibition was reversed by farnesyl pyrophosphate (FPP) or geranylgeranyl pyrophosphate (GGPP). Similar to simvastatin, inhibition of FPP transferase or GGPP transferase suppressed CSE-mediated MMP-9 induction. Simvastatin attenuated CSE-mediated activation of RAS and phosphorylation of ERK, Akt, p65, IkappaB, and nuclear AP-1 or NF-kappaB activity. Taken together, these results suggest that simvastatin may inhibit CSE-mediated MMP-9 induction, primarily by blocking prenylation of RAS in the signaling pathways, in which Raf-MEK-ERK, PI3K/Akt, AP-1, and IkappaB-NF-kappaB are involved.
1-Phosphatidylinositol 3-Kinase/metabolism ; Alkyl and Aryl Transferases/metabolism ; Animals ; Anticholesteremic Agents/pharmacology ; Cells, Cultured ; Enzyme Inhibitors/metabolism/pharmacology ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Gene Expression Regulation, Enzymologic/*drug effects ; I-kappa B Kinase/antagonists & inhibitors/metabolism ; Macrophages, Alveolar/cytology/*drug effects/*enzymology ; Matrix Metalloproteinase 9/genetics/*metabolism ; Mitogen-Activated Protein Kinase Kinases/metabolism ; Polyisoprenyl Phosphates/metabolism ; Proto-Oncogene Proteins c-akt/metabolism ; Rats ; Sesquiterpenes/metabolism ; Signal Transduction/physiology ; Simvastatin/*pharmacology ; Smoke/*adverse effects ; *Tobacco/adverse effects/chemistry

Adhesion and migration of vascular smooth muscle cells (VSMCs) play an important role in the pathogenesis of atherosclerosis. These processes involve the interaction of VSMCs with extracellular matrix proteins. Here, we investigated integrin isoforms and signaling pathways mediating the adhesion and migration of VSMCs on betaig-h3, a transforming growth factor (TGF)-beta-inducible extracellular matrix protein that is elevated in atherosclerotic plaques. Adhesion assays showed that the alphavbeta5 integrin is a functional receptor for the adhesion of aortic VSMCs to betaig-h3. An YH18 motif containing amino acids between 563 and 580 of betaig-h3 was an essential motif for the adhesion and growth of VSMCs. Interaction between the YH18 motif and the alphavbeta5 integrin was responsible for the migration of VSMCs on betaig-h3. Inhibitors of phosphatidylinositide 3-kinase, extracellular signal-regulated kinase (ERK), and Src kinase reduced the adhesion and migration of VSMCs on betaig-h3. betaig-h3 triggered phosphorylation and activation of AKT, ERK, focal adhesion kinase, and paxillin mediating the adhesion and migration of VSMCs. Taken together, these results suggest that betaig-h3 and alphavbeta5 integrin play a role in the adhesion and migration of VSMCs during the pathogenesis of atherosclerosis.
src-Family Kinases/antagonists & inhibitors ; Transforming Growth Factor beta/genetics/*physiology ; Signal Transduction/*physiology ; Receptors, Vitronectin/genetics/*physiology ; Protein-Tyrosine Kinases/antagonists & inhibitors ; Paxillin/metabolism ; Myocytes, Smooth Muscle/drug effects/metabolism ; Muscle, Smooth, Vascular/cytology/drug effects/*metabolism ; Morpholines/pharmacology ; Molecular Sequence Data ; Integrins/genetics/*physiology ; Humans ; Flavonoids/pharmacology ; Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors ; Extracellular Matrix Proteins/genetics/*physiology ; Enzyme Inhibitors/pharmacology ; Chromones/pharmacology ; Cells, Cultured ; Cell Movement/*physiology ; Cell Adhesion/physiology ; Animals ; Amino Acid Sequence ; Amino Acid Motifs/genetics ; 1-Phosphatidylinositol 3-Kinase/antagonists & inhibitors

Prostaglandin E2(PGE2), a major product of cyclooxygenase, has been implicated in modulating angiogenesis, vascular function, and inflammatory processes, but the underlying mechanism is not clearly elucidated. We here investigated the molecular mechanism by which PGE 2 regulates angiogenesis. Treatment of human umbilical vein endothelial cells (HUVEC) with PGE 2 increased angiogenesis. PGE 2 increased phosphorylation of Akt and endothelial nitric oxide synthase (eNOS), eNOS activity, and nitric oxide (NO) production by the activation of cAMP-dependent protein kinase (PKA) and phosphatidylinositol 3-kinase (PI3K). Dibutyryl cAMP (DB-cAMP) mimicked the role of PGE 2 in angiogenesis and the signaling pathway, suggesting that cAMP is a down-stream mediator of PGE 2. Furthermore, PGE 2 increased endothelial cell sprouting from normal murine aortic segments, but not from eNOS-deficient ones, on Matrigel. The angiogenic effects of PGE 2 were inhibited by the inhibitors of PKA, PI3K, eNOS, and soluble guanylate cyclase, but not by phospholipase C inhibitor. These results clearly show that PGE 2 increased angiogenesis by activating the NO/cGMP signaling pathway through PKA/PI3K/Akt-dependent increase in eNOS activity.
1-Phosphatidylinositol 3-Kinase/antagonists & inhibitors ; Animals ; Aorta ; Cell Movement/drug effects ; Cell Proliferation/drug effects ; Cyclic AMP/metabolism/pharmacology ; Cyclic GMP/biosynthesis/*metabolism ; Dinoprostone/*pharmacology ; Endothelial Cells/*drug effects/metabolism ; Enzyme Inhibitors/pharmacology ; Humans ; Mice ; Mice, Knockout ; Neovascularization, Physiologic/*drug effects ; Nitric Oxide/biosynthesis/*metabolism ; Nitric Oxide Synthase Type III/deficiency/metabolism ; Phosphorylation/drug effects ; Proto-Oncogene Proteins c-akt/metabolism ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; Signal Transduction/*drug effects ; Umbilical Veins/cytology/*drug effects/metabolism