Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our recent study indicates that lysophosphatidylcholine (LPC) enhances Sp1 binding and Sp1-dependent endothelial nitric oxide synthase (eNOS) promoter activity via the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1 (MEK-1) signaling pathway (Cieslik, K., Lee, C.-M., Tang, J.-L., and Wu, K. K. (1999) J. Biol. Chem. 274, 34669-34675). To identify upstream signaling molecules, we transfected human endothelial cells with dominant negative and active mutants of Ras and evaluated their effects on eNOS promoter activity. Neither mutant altered the basal or LPC-induced eNOS promoter function. By contrast, a dominant negative mutant of phosphatidylinositol 3-kinase gamma (PI-3Kgamma) blocked the promoter activity induced by LPC. Wortmannin and LY 294002 had a similar effect. AG-490, a selective inhibitor of Janus kinase 2 (Jak2), also reduced the LPC-induced Sp1 binding and eNOS promoter activity to the basal level. LPC induced Jak2 phosphorylation, which was abolished by LY 294002 and the dominant negative mutant of PI-3Kgamma. LY 294002 and AG-490 abrogated MEK-1 phosphorylation induced by LPC but had no effect on Raf-1. These results indicate that PI-3Kgamma and Jak2 are essential for LPC-induced eNOS promoter activity. This signaling pathway was sensitive to pertussis toxin, suggesting the involvement of a G(i) protein in PI-3Kgamma activation. These results indicate that LPC enhances Sp1-dependent eNOS promoter activity by a pertussis toxin-sensitive, Ras-independent novel pathway, PI-3Kgamma/Jak2/MEK-1/ERK1/2.
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PMID:Up-regulation of endothelial nitric-oxide synthase promoter by the phosphatidylinositol 3-kinase gamma /Janus kinase 2/MEK-1-dependent pathway. 1104 69

Lysophosphatidic acid (LPA) is a naturally occurring phospholipid with multiple biological functions. In the present study, we demonstrate that, besides its mitogenic activity, LPA is a potent survival factor, preventing serum-deprivation-induced apoptosis in fibroblasts and other cell types. Both the proliferative effect and survival activity of LPA are sensitive to the action of pertussis toxin (PTX), indicating that both processes are mediated by G(i) protein(s). We therefore focused on the role of G(i)-protein-mediated signalling events in the promotion of cell survival by LPA. In addition to activation of mitogen-activated protein kinase (MAPK), LPA stimulates a modest PTX-sensitive phosphorylation/activation of the serine/threonine kinase Akt, a survival mediator downstream of phosphoinositide 3-kinase (PI3K). Inhibition of PI3K with LY 294002 or wortmannin resulted in a marked inhibition of LPA-induced DNA synthesis, and yet the survival activity of LPA decreased by only 20-30%, suggesting a limited input of the PI3K-Akt cascade in LPA-induced cell survival. In contrast, inhibition of MAPK activation by the MEK-1 inhibitor, PD 98059, blocked both the proliferative and survival effects of LPA. These results indicate that LPA promotes cell survival largely via G(i)-protein-mediated activation of ERK1/ERK2, or other PD 98059-sensitive member(s) of the MAPK family.
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PMID:Lysophosphatidic acid prevents apoptosis in fibroblasts via G(i)-protein-mediated activation of mitogen-activated protein kinase. 1106 66

We have recently shown that pretreatment with endothelin-1 (ET-1) for 20 min stimulates GLUT4 translocation in a PI3-kinase-dependent manner in 3T3-L1 adipocytes (Imamura, T. et al., J Biol Chem 274:33691-33695). This study presents another pathway by which ET-1 potentiates glucose transport in 3T3-L1 adipocytes. ET-1 treatment (10 nM) leads to approximately 2.5-fold stimulation of 2-deoxyglucose (2-DOG) uptake within 20 min, reaching a maximal effect of approximately 4-fold at approximately 6 h, and recovering almost to basal levels after 24 h. Insulin treatment (3 ng/ml) results in an approximately 5-fold increase in 2-DOG uptake at 1 h, and recovering to basal levels after 24 h. The ETA receptor antagonist, BQ 610, inhibited ET-1 induced glucose uptake both at 20 min and 6 h, whereas the ETB receptor antagonist, BQ 788, was without effect. Interestingly, ET-1 stimulated 2-DOG uptake at 6 h, not at 20 min, was almost completely blocked by the protein-synthesis inhibitor, cycloheximide and the RNA-synthesis inhibitor, actinomycin D, suggesting that the short-term (20 min) and long-term (6 h) effects of ET-1 involve distinct mechanisms. GLUT4 translocation assay showed that 20 min, but not 6 h, exposure to ET-1 led to GLUT4 translocation to the plasma membrane. In contrast, 6 h, but not 20 min, exposure to ET-1 increased expression of the GLUT1 protein, without affecting expression of GLUT4 protein. ET-1 induced 2-DOG uptake and GLUT1 expression at 6 h were completely inhibited by the MEK inhibitor, PD 98059, and partially inhibited by the PI3-kinase inhibitor, LY 294002, and the G alpha i inhibitor, pertussis toxin. The PLC inhibitor, U 73122, was without effect. These findings suggest that ET-1 induced GLUT1 protein expression is primarily mediated via MAPK, and partially via PI3K in 3T3-L1 adipocytes.
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PMID:The acute and chronic stimulatory effects of endothelin-1 on glucose transport are mediated by distinct pathways in 3T3-L1 adipocytes. 1110 76

Ischemic preconditioning improves liver resistance to hypoxia and reduces reperfusion injury following transplantation. However, the intracellular signals that mediate the development of liver hypoxic preconditioning are largely unknown. We have investigated the signal pathway leading to preconditioning in freshly isolated rat hepatocytes. Hepatocytes were preconditioned by 10-minute incubation under hypoxic conditions followed by 10 minutes of reoxygenation and subsequently exposed to 90 minutes of hypoxia. Preconditioning reduced hepatocyte killing by hypoxia by about 35%. A similar protection was also obtained by preincubation with chloro-adenosine or with A(2A)-adenosine receptor agonist CGS21680, whereas A(1)-adenosine receptor agonist N-phenyl-isopropyladenosine (R-PIA) was inactive. Conversely, the development of preconditioning was blocked by A(2)-receptor antagonist 3,7-dimethyl-1-propargylxanthine (DMPX), but not by A(1)-receptor antagonist 8-cyclopenthyl-1, 3-dipropylxanthine (DPCPX). In either preconditioned or CGS21680-treated hepatocytes a selective activation of delta and epsilon protein kinase C (PKC) isoforms was also evident. Inhibition of heterotrimeric G(i) protein or of phospholypase C by, respectively, pertussis toxin or U73122, prevented PKC activation as well as the development of preconditioning. MEK inhibitor PD98509 did not interfere with preconditioning that was instead blocked by p38 MAP kinase inhibitor SB203580. The direct activation of p38 MAPK by anisomycin A mimicked the protection against hypoxic injury given by preconditioning. Consistently, an increased phosphorylation of p38 MAPK was observed in preconditioned or CGS21680-treated hepatocytes, and this effect was abolished by PKC-blocker, chelerythrine. We propose that a signal pathway involving A(2A)-adenosine receptors, G(i)-proteins, phospholypase C, delta- and epsilon-PKCs, and p38 MAPK, is responsible for the development of liver ischemic preconditioning.
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PMID:Signal pathway involved in the development of hypoxic preconditioning in rat hepatocytes. 1112 29

The potential of primary cultures of rabbit renal artery vascular smooth muscle cells (VSMCs) was assessed as a means to investigate the signalling pathways linked to 5-hydroxytryptamine (5-HT) 5-HT(1B)/5-HT(1D) receptors in native arteries. In renal artery segments denuded of endothelium, incubated with ketanserin and prazosin (each 1 microM), and prestimulated with 20 mM K(+) Krebs buffer, 5-HT and CP 93,129, a 5-HT(1B) receptor agonist, evoked concentration-dependent contractions. GR 127935, a 5-HT(1B)/5-HT(1D) receptor antagonist, significantly antagonised 5-HT-evoked contractions at nanomolar concentrations. Reverse transcription polymerase chain reaction (RT-PCR) of mRNA from smooth muscle cells from the isolated renal artery and from primary cultures of VSMCs from the same artery expressed mRNA transcripts for the 5-HT(1B) receptor and the 5-HT(1D) receptor in both preparations. The sequence of the PCR fragments corresponded to the known sequence for these receptors. Application of 5-HT evoked a concentration-dependent, pertussis toxin (PTx)-sensitive reduction in cyclic AMP in both cultured cells and intact artery (cyclic AMP concentration reduced by 65.53 +/- 3.33 and 52.65 +/- 5.34% from basal with 10 microM 5-HT, respectively). The effect of 10 microM 5-HT on cAMP was increased in the presence of 20 mM K(+) (reduced by 82.50 +/- 2.50 and 87.54 +/- 3.97%, respectively). In intact arteries, contraction through 5-HT(1B)/5-HT(1D) receptors was significantly attenuated by inhibitors of phosphatidylinositol 3-kinase (wortmannin) and activated mitogen-activated protein kinase (MAPK), MEK (U0126). In the cultured VSMCs, activated MAPK was identified by immunocytochemistry and immunoblotting after stimulation with 5-HT, but only if 20 mM K(+) was present at the onset of stimulation. These data provide the first direct evidence that 5-HT(1B)/5-HT(1B) receptors are linked to the activation of MAPK and indicate that primary cultures of renal VSMCs could provide a model system to study further the signalling pathways linked to these receptors.
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PMID:Signalling pathways activated by 5-HT(1B)/5-HT(1D) receptors in native smooth muscle and primary cultures of rabbit renal artery smooth muscle cells. 1114 99

We report that prosaposin treatment induced extracellular signal-regulated kinases (ERKs) and sphingosine kinase activity, increased DNA synthesis, and prevented cell apoptosis. Prosaposin treatment induced pheochromocytoma cells (PC12) to enter the S phase of the cell cycle; this effect was inhibited by the MEK inhibitor PD98059, indicating that prosaposin-induced ERK phosphorylation is required for stimulation of DNA synthesis. The prosaposin effect was also inhibited by pertussis toxin, indicating that the prosaposin receptor is a G-protein-coupled receptor. Prosaposin rescued PC12 cells from apoptosis induced by staurosporine or ceramide. Sphingosine kinase activity was increased by prosaposin treatment. We propose that this effect is a mechanism underlying the proliferative and anti-apoptotic functions of prosaposin. Prosaposin appears to be a key regulatory factor in the ceramide-S-1-P rheostat, which regulates cell fate.
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PMID:Prosaposin treatment induces PC12 entry in the S phase of the cell cycle and prevents apoptosis: activation of ERKs and sphingosine kinase. 1115 62

The simple glycerophospholipid lysophosphatidic acid (LPA) acts both as an intermediary in phospholipid metabolism and as an intercellular signaling molecule in its own right. In various cell types, LPA signals through its membrane-bound, G protein-coupled receptors to influence cellular processes such as proliferation, survival, and cytoskeletal function. Its actions in bone cells have not been studied. Here we show that the LPA receptor, LP(A1)/edg-2/vzg-1, is expressed in primary rat osteoblasts and the UMR 106-01 osteoblastic cell line. LPA potently induces DNA synthesis and an increase in cell number in cultures of osteoblastic cells. LPA rapidly (within 10 min) stimulates phosphorylation of p42/44 mitogen-activated protein (MAP) kinases in osteoblastic cells, an effect that is sensitive to inhibition of G(i) proteins, inhibition of influx of extracellular calcium, and inhibition of protein kinase C. LPA-induced DNA synthesis is partially inhibited by either pertussis toxin or calphostin C, but is insensitive to specific inhibitors of MEK, the kinase upstream of p42/44 MAP kinases, or of phosphatidylinositol-3 kinases. These data demonstrate that LPA is an osteoblast mitogen whose signaling effects in osteoblastic cells include activation of p42/44 MAP kinases. However, the LPA mitogenic signal in osteoblastic cells, while requiring G(i) proteins and protein kinase C, is independent of the activity of p42/44 MAP kinases.
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PMID:Lysophosphatidic acid is an osteoblast mitogen whose proliferative actions involve G(i) proteins and protein kinase C, but not P42/44 mitogen-activated protein kinases. 1118 24

We investigated a signaling pathway leading to activation of extracellular signal-regulated protein kinase (Erk) 1 and 2 in Rat-2 cells stimulated with sphingosine 1-phosphate (S1P). S1P treatment transiently activated Erk-1/-2 in a dose-dependent manner, and its activation was blocked by pertussis toxin, expression of RasN17, or inhibition of Raf or MEK-1/-2. S1P-induced activation of Erk-1/-2 was also suppressed by the inhibition of epidermal growth factor (EGF) receptor tyrosine kinase with the specific inhibitor AG1478, suggesting that activation of EGF receptor tyrosine kinase was involved in the signaling pathway. S1P-induced Erk-1/-2 activation was enhanced up to 2-fold by inhibiting protein kinase C (PKC) with GF109203X, and PKC inhibition in the absence of S1P treatment also activated Erk-1/-2. The stimulatory effects of Erk-1/-2 activation by PKC inhibition was blocked by treating cells with AG1478, suggesting the involvement of PKC in the regulation of EGF receptor tyrosine kinase activation that leads to Erk-1/-2 activation. Together, these results suggest that S1P activates the EGF receptor through a PKC-dependent pathway that links Ras signaling to the activation of Erk-1/-2 in Rat-2 cells.
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PMID:Sphingosine 1-phosphate activates Erk-1/-2 by transactivating epidermal growth factor receptor in rat-2 cells. 1118 56

In the ovary it has been demonstrated that PGF(2alpha) activates the phospholipase C (PLC)/diacylglycerol/protein kinase C pathway. However, little is known about the downstream signaling events that mediate subsequent cellular responses such as steroidogenesis. The present study was designed to examine the effect of PGF(2alpha) on activation of the mitogen-activated protein kinase (MAPK) signaling pathway and its physiological role in human granulosa-luteal cells (hGLCs). Human GLCs, obtained from women undergoing in vitro fertilization-embryo transfer, were treated with increasing concentrations of PGF(2alpha) (10 nmol/L to 10 micromol/L) for 5 min. For time-course experiments, hGLCs were treated with 1 micromol/L PGF(2alpha) for 1, 5, 10, or 20 min. Western blot analysis, using a monoclonal antibody that detected the phosphorylated forms of extracellular signal-regulated kinases 1 and 2 (p42(mapk) and p44(mapk), respectively), demonstrated that PGF(2alpha) activated MAPK in hGLCs in a dose- and time-dependent manner. Treatment of the cells with neomycin (10 mmol/L; a PLC inhibitor), bisindolylmaleimide I (5 micromol/L; a PKC inhibitor), or PD98059 (50 micromol/L; a MEK inhibitor and a MAPK kinase inhibitor) significantly attenuated the PGF(2alpha)-induced activation of MAPK. In contrast, MAPK activation was not significantly affected by pertussis toxin (200 ng/mL; a G(i) inhibitor) pretreatment. To determine the role of MAPK in steroidogenesis, hGLCs were treated with PGF(2alpha) (1 micromol/L), hCG (1 IU/mL), or PGF(2alpha) plus hCG in the presence or absence of PD98059. Progesterone levels in the culture medium were examined by RIA. Treatment of hGLCs with PGF(2alpha) significantly inhibited hCG-induced progesterone production. The presence of the MEK inhibitor, PD98059, reversed the inhibitory effect of PGF(2alpha) on hCG-induced progesterone production. To our knowledge, it is the first demonstration of PGF(2alpha)-induced activation of the MAPK signaling pathway in the human ovary. These results indicated that PGF(2alpha) activated MAPK subsequent to PLC and PKC activation through pertussis toxin-insensitive G protein in hGLCs. Further, we demonstrated that PGF(2alpha)-induced MAPK activation is associated with modulation of progesterone production. These results support the idea that the MAPK signaling pathway is involved in mediating PGF(2alpha) actions in the human ovary.
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PMID:Role of mitogen-activated protein kinase in prostaglandin f(2alpha) action in human granulosa-luteal cells. 1123 27

It has been demonstrated that proinsulin C-peptide possesses several biological activities and that its specific binding sites are present on the surface of cell membranes. However, the molecular and cellular mechanisms of C-peptide actions are poorly known. In the present study we examined the possible involvement of the mitogen-activated protein kinase (MAPK) pathway in C-peptide effects. C-peptide induced the phosphorylation of MAPK [p44 extracellular signal-regulated kinase 1 (ERK1) and p42 ERK2] in Swiss 3T3 and 3T3-F442A fibroblasts but not in 3T3-L1 fibroblasts and some other cell lines such as L(6)E(9) muscle cells. In Swiss 3T3 cells, C-peptide-induced phosphorylation of MAPK was dependent on time and concentration, being maximal at 1 min and at 1 nM C-peptide and was accompanied by an increase in MAPK activity and MAPK kinase (MEK) phosphorylation. The MAPK phosphorylation by C-peptide was abolished by treatment with pertussis toxin (PTX) and also with a MEK inhibitor, PD 98059. In addition, MAPK phosphorylation was attenuated by treatment with a phosphoinositide 3-kinase (PI-3K) inhibitor, wortmannin, and with a protein kinase C (PKC) inhibitor, GF109203X, and by down-regulation of PKC by prolonged treatment with PMA. Similar effects of the inhibitors and PTX were found on the MAPK phosphorylation induced by neuropeptide Y. These results suggest that C-peptide activates MAPK through a putative G(i)/G(o)-linked receptor for C-peptide and through PI-3K-dependent and PKC-dependent pathways.
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PMID:Proinsulin C-peptide rapidly stimulates mitogen-activated protein kinases in Swiss 3T3 fibroblasts: requirement of protein kinase C, phosphoinositide 3-kinase and pertussis toxin-sensitive G-protein. 1125 56


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