Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0406810 (NAME)
 13,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intracellular signaling pathways that are involved in protection of vascular smooth muscle cells (VSMC) from apoptosis remain poorly understood. This study examines the effect of activators of cAMP/cGMP signaling on apoptosis in non-transfected VSMC and in VSMC transfected with c-myc (VSMC-MYC) or with its functional analogue, E1A-adenoviral protein (VSMC-E1A). Serum-deprived VSMC-E1A exhibited the highest apoptosis measured as the content of chromatin and low molecular weight DNA fragments, phosphatidylserine content in the outer surface of plasma membrane and caspase-3 activity (ten-, five-, four- and tenfold increase after 6 h of serum withdrawal, respectively). In VSMC-E1A, the addition of an activator of adenylate cyclase, forskolin, abolished chromatin cleavage, DNA laddering, caspase-3 activation and the appearance of morphologically-defined apoptotic cells triggered by 6 h of serum deprivation. In non-transfected VSMC and in VSMC-MYC, 6 h serum deprivation led to approximately six- and threefold activation of chromatin cleavage, respectively, that was also blocked by forskolin. In VSMC-E1A, inhibition of apoptosis was observed with other activators of cAMP signaling (cholera toxin, isoproterenol, adenosine, 8-Br-cAMP), whereas 6 h incubation with modulators of cGMP signaling (8-Br-cGMP, nitroprusside, atrial natriuretic peptide, L-NAME) did not affect the development of apoptotic machinery. The antiapoptotic effect of forskolin was abolished in 24 h of serum deprivation that was accompanied by normalization of intracellular cAMP content and protein kinase A (PKA) activity. Protection of VSMC-E1A from apoptosis by forskolin was blunted by PKA inhibitors (H-89 and KT5720), whereas transfection of cells with PKA catalytic subunit attenuated apoptosis triggered by serum withdrawal. The protection of VSMC-E1A by forskolin from apoptosis was insensitive to modulators of cytoskeleton assembly (cytochalasin B, colchicine). Neither acute (30 min) nor chronic (24 h) exposure of VSMC to forskolin modified basal and serum-induced phosphorylation of the MAP kinase ERK1/2. Thus, our results show that activation of cAMP signaling delays the development of apoptosis in serum-deprived VSMC at a site upstream of caspase-3 via activation of PKA and independently of cAMP-induced reorganization of the cytoskeleton network and the ERK1/2-terminated MAPK signaling cascade.
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PMID:Activation of cAMP signaling transiently inhibits apoptosis in vascular smooth muscle cells in a site upstream of caspase-3. 1045 77

The nitric oxide synthase (NOS) inhibitor L-NAME may have growth inhibitory effects in vivo. We investigated in vitro the potential growth inhibitory effects of three different NOS inhibitors: L-NAME (1 mM), LNMMA (1 mM) and aminoguanidine (0.5 mM), on fetal bovine serum (FBS) and platelet derived growth factor (PDGF-BB)-stimulated growth in cultured vascular smooth muscle cells (VSMCs). [3H]-thymidine incorporation into rat mesenteric VSMCs was measured as an index of VSMCs proliferation (DNA synthesis) and activation of extracellular signal regulated kinase (ERK1/2), a major signaling event in cell growth, was measured by western blot assay. PDGF-BB (0-5 ng/mL) and FBS (0-5%) increased [3H]-thymidine incorporation in a dose-dependent manner up to 6-10 fold. L-NAME significantly reduced PDGF-BB (5 ng/ml) and FBS (5%) stimulated DNA synthesis by 46% and 38% respectively. The increase of [3H]-thymidine incorporation induced by PDGF-BB and FBS was unaltered by L-NMMA. In contrast, aminoguanidine induced an increase in FBS and PDGF-BB-stimulated [3H]-thymidine incorporation of 64% and 34% respectively above cells not exposed to aminoguanidine. ERK1/2 phosphorylation induced by PDGF-BB and FBS was not affected by pre-treatment with L-NAME or aminoguanidine. In conclusion, NOS inhibitors differentially influence DNA synthesis in VSMCs: L-NAME inhibits FBS and PDGF-BB-stimulated cellular proliferation whereas aminoguanidine accentuates FBS and PDGF-BB-stimulated VSMCs proliferation. These phenomena are independent of the ERK1/2 pathway. The growth inhibitory effects of L-NAME may be related to differences in properties from other NOS inhibitors, and independent of its ability to inhibit NOS.
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PMID:Antiproliferative effect of L-NAME on rat vascular smooth muscle cells. 1098 55

The effects of elevated D-glucose on adenosine transport were investigated in human cultured umbilical vein endothelial cells isolated from normal pregnancies. Elevated D-glucose resulted in a time- (8-12 h) and concentration-dependent (half-maximal at 10+/-2 mM) inhibition of adenosine transport, which was associated with a reduction in the Vmax for nitrobenzylthioinosine (NBMPR)-sensitive (es) saturable nucleoside with no significant change in Km. d-Fructose (25 mM), 2-deoxy-D-glucose (25 mM) or D-mannitol (20 mM) had no effect on adenosine transport. Adenosine transport was inhibited following incubation of cells with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA; 100 nM, 30 min to 24 h). D-Glucose-induced inhibition of transport was abolished by calphostin C (100 nM, an inhibitor of PKC), and was not further reduced by PMA. Increased PKC activity in the membrane (particulate) fraction of endothelial cells exposed to D-glucose or PMA was blocked by calphostin C but was unaffected by NG-nitro-L-arginine methyl ester (L-NAME; 100 microM, an inhibitor of nitric oxide synthase (NOS)) or PD-98059 (10 microM, an inhibitor of mitogen-activated protein kinase kinase 1). D-Glucose and PMA increased endothelial NOS (eNOS) activity, which was prevented by calphostin C or omission of extracellular Ca2+ and unaffected by PD-98059. Adenosine transport was inhibited by S-nitroso-N-acetyl-l, d-penicillamine (SNAP; 100 microM, an NO donor) but was increased in cells incubated with L-NAME. The effect of SNAP on adenosine transport was abolished by PD-98059. Phosphorylation of mitogen-activated protein kinases p44mapk (ERK1) and p42mapk (ERK2) was increased in endothelial cells exposed to elevated D-glucose (25 mM for 30 min to 24 h) and the NO donor SNAP (100 microM, 30 min). The effect of D-glucose was blocked by PD-98059 or L-NAME, which also prevented the inhibition of adenosine transport mediated by elevated D-glucose. Our findings provide evidence that D-glucose inhibits adenosine transport in human fetal endothelial cells by a mechanism that involves activation of PKC, leading to increased NO levels and p42-p44mapk phosphorylation. Thus, the biological actions of adenosine appear to be altered under conditions of sustained hyperglycaemia.
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PMID:Regulation of adenosine transport by D-glucose in human fetal endothelial cells: involvement of nitric oxide, protein kinase C and mitogen-activated protein kinase. 1111 5

Prominent neurite outgrowth induced by genipin, a plant-derived iridoid, was substantially inhibited by addition of NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase (NOS) inhibitor, and carboxy-PTIO, an NO scavenger, in PC12h cells. Increases of the NADPH-diaphorase activity and neuronal and inducible NOS proteins in cells preceded the neurite outgrowth after addition of genipin to medium. NO donors could induce the neurite outgrowth dose-dependently in the cells. On the other hand, an inhibitor of soluble guanylate cyclase (SGC), which is known to be a stimulatory target of NO, abolished greatly the genipin-induced neurite outgrowth. Addition of extracellular signal-regulated kinase (ERK) kinase inhibitors could almost completely abolish the neurite induction. L-NAME remarkably depressed genipin-stimulated phosphorylation of ERK-1 and -2. A neuritogenic effect of nerve growth factor (NGF) in PC12h cells was also remarkably inhibited by the NOS inhibitor, NO scavenger and SGC inhibitor. These findings suggest that induced NO production followed by cyclic GMP-mediated stimulation of the mitogen-activated protein kinase (MAPK) cascade is implicated in the neuritogenesis by genipin and NGF in PC12h cells.
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PMID:Activation of the mitogen-activated protein kinase cascade through nitric oxide synthesis as a mechanism of neuritogenic effect of genipin in PC12h cells. 1159 56

Melanosome movement represents a good model of cytoskeleton-mediated transport of organelles in eukaryotic cells. We recently observed that inhibiting nitric oxide synthase (NOS) with Nomega-nitro-L-arginine methyl ester (L-NAME) induced dispersion in melanophores pre-aggregated with melatonin. Activation of cyclic adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase (PKA) or calcium-dependent protein kinase (PKC) is known to cause dispersion. Also, PKC and NO have been shown to regulate the mitogen/extracellular signal-regulated kinase (MEK)-ERK pathway. Accordingly, our objective was to further characterize the signaling pathway of L-NAME-induced dispersion. We found that the dispersion was decreased by staurosporine and PD98059, which respectively inhibit PKC and MEK, but not by the PKA inhibitor H89. Furthermore, Western blotting revealed that ERK1 kinase was phosphorylated in L-NAME-dispersed melanophores. L-NAME also caused dispersion in latrunculin-B-treated cells, suggesting that this effect is not due to inhibition of the melatonin signaling pathway. Summarizing, we observed that PKC and MEK inhibitors decreased the L-NAME-induced dispersion, which caused phosphorylation of ERK1. Our results also suggest that NO is a negative regulator of phosphorylations that leads to organelle transport.
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PMID:L-NAME-induced dispersion of melanosomes in melanophores activates PKC, MEK and ERK1. 1177 57

Extracellular regulated kinases (ERKs)-1 and -2 are members of the MAPK family of protein kinases involved in the proliferation, differentiation, and apoptosis of bone cells. We have shown previously that ROS 17/2.8 cells show increased activation of ERK-1 or -2, which is sustained for 24 h, when the strips onto which they are seeded are subjected to a 10 min period of cyclic four point bending that produces physiological levels of mechanical strain along with associated fluid movement of the medium. Movement of the strips through the medium without bending causes fluid movement without strain. This also increases ERK-1/2 activation, but in a biphasic manner over the same time period. Our present study investigates the role of components of signaling pathways in the activation of ERK-1/2 in ROS 17/2.8 cells in response to these stimuli. Using a range of inhibitors we show specific differences by which ERK-1 and ERK-2 are activated in response to fluid movement alone, compared with those induced in response to strain plus its associated fluid movement. ERK-1 activation induced by fluid movement was markedly reduced by nifedipine, and therefore appears to involve L-type calcium channels, but was unaffected by either L-NAME or indomethacin. This suggests independence from prostacyclin (PGI(2)) and nitric oxide (NO) production. In contrast, ERK-1 activation induced by application of strain (and its associated fluid disturbance) was abrogated by TMB-8 hydrochloride, L-NAME, and indomethacin. This suggests that strain-induced ERK-1 activation is dependent upon calcium mobilization from intracellular stores and production of NO and PGI(2). ERK-2 activation appears to be mediated by a separate mechanism in these cells. Its activation by fluid movement alone involved both PGI(2) and NO production, but its activation by strain was not affected by any of the inhibitors used. The G protein inhibitor, pertussis toxin, did not cause a reduction in the activation of ERK-1 or -2 in response to either stimulus. These results are consistent with earlier observations of ERK activation in bone cells in response to both strain (with fluid movement) and fluid movement alone, and further demonstrate that these phenomena stimulate distinct signaling pathways.
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PMID:Mechanical strain and fluid movement both activate extracellular regulated kinase (ERK) in osteoblast-like cells but via different signaling pathways. 1211 Apr 33

Hepatocyte growth factor (HGF) is a potent mitogen for vascular endothelial cells (EC); however, signal transduction pathways for HGF-stimulated EC growth remain unclear. In the present study we investigated the role of Src family kinases and nitric oxide (NO) in HGF-stimulated EC growth. Human umbilical vein endothelial cells (HUVEC) were stimulated with HGF and NO was measured by an NOx analyzing HPLC system. Activation of ERK1/2 and p38 MAPK was assessed by Western blot. NO production in HUVEC increased 1.8-fold by HGF. A Src family kinases inhibitor PP1 inhibited HGF-stimulated NO production by 71%. HUVEC growth increased 1.9-fold in cell number by HGF. PP1 and Nitro-L-arginine methylester (L-NAME) inhibited HGF-stimulated HUVEC growth by 51 and by 71%. ERK1/2 and p38 MAPK were phosphorylated by HGF and a MEK inhibitor PD98059 and a p38 MAPK inhibitor SB203580 inhibited HGF-stimulated HUVEC growth by 66% and by 58%; however, HGF-induced phosphorylation of ERK1/2 and p38 MAPK was not inhibited by L-NAME, indicating that NO is not an upstream activator of ERK1/2 and p38 MAPK. These findings demonstrated that Src family kinases regulate HGF-stimulated NO production in HUVEC and that HGF stimulates HUVEC growth through NO-dependent and NO-independent pathways.
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PMID:Src family kinases and nitric oxide production are required for hepatocyte growth factor-stimulated endothelial cell growth. 1261 72

As in essential hypertension, chronic nitric-oxide synthase (NOS) inhibition leads to hypertrophic remodeling in conduit and muscular arteries and inward eutrophic remodeling in small resistance arteries with activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in both vessel types. The authors tested the hypothesis that this remodeling heterogeneity could be related to distinct vasoreactivity patterns in small and larger arteries, with a vessel-specific function of ERK1/2 signaling. Using intravital microscopy in rats we have demonstrated that acute NOS inhibition (l-NA injection, 100 mg/kg) produced vasoconstriction of small mesenteric arteries. Consequently, the calculated in vivo wall stress was not significantly modified, despite the local rise in pressure. This could explain the lack of vascular protein synthesis elevation in vivo, an early index of hypertrophy. Inhibition of ERK1/2 activation with PD98059 blunted mesenteric artery contractions. Femoral arteries did not contract and were thus submitted to an enhanced wall stress and underwent hypertrophic remodeling in chronic conditions. In conclusion, the heterogeneous vascular remodeling in the l-NAME model is associated with a heterogeneous vasoconstriction response to acute NOS inhibition. Indeed, in contrast to larger arteries, l-NA-induced vasoconstriction in small arteries normalized wall stress and prevented early signs of hypertrophy. The results also suggest that ERK1/2 is a signaling element in NOS inhibition-induced vasoconstriction of small arteries in vivo.
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PMID:ERK1/2-mediated vasoconstriction normalizes wall stress in small mesenteric arteries during NOS inhibition in vivo. 1296 Jun 78

Post-ischemic interventions that activate phosphatidylinositol-3-OH kinase (PI3K)-Akt or ERK1/2 pro-survival kinases (the so-called "reperfusion injury signalling kinase (RISK) pathway") during the first few minutes of reperfusion protect against lethal reperfusion-induced injury. We have previously shown that insulin protects against reperfusion-induced injury via activation of the PI3K-Akt pathway. In addition, opening of the mitochondrial permeability transition pore (mPTP) at the time of reperfusion is a major determinant of lethal reperfusion-induced injury, and pharmacologically inhibiting it is cardioprotective. In this study, we examined the relationship between the pro-survival kinase pathways and mPTP opening. Specifically, we tested the hypothesis that activation of the pro-survival kinase pathway by insulin protects cardiomyocytes by reducing the probability of mPTP opening upon reperfusion. Laser illumination of the fluorophore, tetramethyl rhodamine methyl ester (TMRM), was used to induce oxidative stress in the preparation of adult rat ventricular cardiomyocytes. Maintained illumination ultimately induces mPTP opening, detected as a global mitochondrial depolarization, followed by ATP depletion and rigor contracture. Insulin significantly delayed mPTP opening by a factor of approximately 1.7-fold (P<0.001). The effect of insulin was prevented by Wortmannin and by LY-294002, inhibitors of the PI3K pathway, by SH-6, a selective inhibitor of Akt, and by L-NAME, an inhibitor of nitric oxide production. The expression of a dominant negative construct of Akt eliminated the effect of insulin in delaying mPTP opening in a cardiac cell line. Furthermore, the overexpression of constitutively active Akt was sufficient to maximally delay mPTP opening. These results indicate that activation of the PI3K-Akt pro-survival kinase pathway inhibits opening of the mPTP, and demonstrate an important link between the survival kinases and the mPTP.
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PMID:Signalling via the reperfusion injury signalling kinase (RISK) pathway links closure of the mitochondrial permeability transition pore to cardioprotection. 1628 Feb 53

Mitogen-activated protein kinases (MAPKs) belong to the group of serine/threonine kinases that are rapidly activated in response to growth factor stimulation. In adult mammalian cells, the MAPK family includes extracellular signal-regulated kinases 1 and 2 (ERK1 and ERK2 or p44mapk and p42mapk), which translocate to the nucleus and integrate signals from second messengers leading to cellular proliferation or differentiation. However, the specific role of MAPKs in neonatal pulmonary vascular smooth muscle is not well understood. Expression of p44mapk and p42mapk in primary cultured pulmonary vascular smooth muscle cells from neonatal (1-2 day old) rats was identified by Western immunoblot analysis. Treatment with 10 nM endothelin-1 (ET-1), a potent vasoconstrictor with vascular mitogenic properties, induced phosphorylation of both p44mapk and p42mapk, but treatment with the exogenous nitric oxide (NO) donor sodium nitroprusside inhibited both p44mapk and p42mapk phosphorylation by ET-1. The specific cGMP-dependent protein kinase (PKG) inhibitor KT5823, the nonspecific nitric oxide synthase (NOS) inhibitor L-NAME, and the specific NOS 1 blocker NPLA all significantly enhanced both p44mapk and p42mapk phosphorylation by ET-1. Collectively, these data demonstrate the expression and phosphorylation of specific MAPKs in rat neonatal pulmonary vascular smooth muscle and suggests that the NO signaling pathway modulates MAPK activation by ET-1.
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PMID:Effect of nitric oxide on mitogen-activated protein kinases in neonatal pulmonary vascular smooth muscle. 1638 25


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