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Query: UMLS:C0043167 (
pertussis
)
19,595
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The presence of endothelin-1 receptor proteins and the expression of their specific mRNAs were studied using 1st passage confluent monolayers of articular chondrocytes, isolated from 1-month and 18-month-old rats following 24-h incubation with several growth factors and cytokines. The
ET-1
- binding sites were predominantly of ETA subtype since BQ123, but not IRL1038 (ETB receptor subtype agonist), effectively blocked 125I-
ET-1
binding. The 18-month-old rat cell monolayers bear approximately twice as many 125I-
ET-1
-binding sites as the 1-month-old rat cells. PDGF, EGF, and IGF-1 increased the number of binding sites in a concentration-dependent manner in both old and young rat cells with PDGF being the most active and EGF more active than IGF-1. IL-1beta, more potently than LPS, increased the number of binding sites in young rat cells only, whereas b-FGF, TGF-beta and GM-CSF had no effect or decreased slightly 125I-
ET-1
binding in both types of cells. TNF-alpha strongly decreased the number of binding sites on both young and old rat cells, only. RT-PCR showed an increased expression of the specific ETA mRNA with the age of animals and in the presence of 50 ng/ml PDGF BB only. The incubation of the cells with ETs 1-3 for 10 min resulted in a 50% decrease of cellular cAMP but the blocking of the receptors with BQ123 prior to their exposure to ETs had no effect on cAMP production whereas IRL1038 counteracted this effect only marginally. This suggests a receptor-independent mechanism for ETs-induced inhibition of cAMP production. However, a 10-min co-incubation of cells with
ET-1
and with one of the following agents: cholera toxin,
pertussis
toxin, indomethacin, L-NMA, U73122 and calphostin resulted in an almost complete (calphostin) or partial suppression of
ET-1
-induced inhibition of cAMP production. The significance of these findings is unclear but the increased density of
ET-1
binding sites on old rat cells and its regulation by certain growth factors or cytokines suggest the involvement of
ET-1
in aging and possibly in age-related diseases.
...
PMID:Endothelin-1 receptors on cultured rat articular chondrocytes: regulation by age, growth factors, and cytokines, and effect on cAMP production. 1129 69
In this present study, the effects of
ET-1
on intracellular free calcium concentration ([Ca2+]i) and the underlying mechanisms were investigated in cultured neonatal rat myocardial cells loaded with fura-2/AM. The results are as follows.
ET-1
induced an increase of [Ca2+]i in a dose-dependent manner, which consisted of a transient and sustained phase. BQ123, a selective ETA receptor antagonist, blocked the
ET-1
induced [Ca2+]i responses, suggesting that these responses were mediated by ETA receptors. After removal of extracellular Ca2+,
ET-1
induced the transient increase of [Ca2+]i without the sustained change. Protein kinase C (PKC) agonist PMA attenuated the
ET-1
induced transient [Ca2+]i increase. Amiloride and nifedipine did not block the [Ca2+]i change induced by
ET-1
. After pretreatment of myocardial cells with
pertussis
toxin,
ET-1
also induced the transient increase of [Ca2+]i but did not affect the sustained increase. These results suggest that the transient [Ca2+]i increase may involve pertussis toxin-insensitive G protein and the sustained one may be caused by extracellular calcium influx, in which
pertussis
toxin sensitive G protein is involved. Furthermore, PKC, but not Na+/H+ exchange, plays an important role in these effects.
...
PMID:[Effect of ET-1 on intracellular free calcium in cultured neonatal myocardial cells]. 1149 66
In this study, we analyzed in rat myometrial cells the signaling pathways involved in the endothelin (ET)-1-induced extracellular signal-regulated kinase (ERK) activation required for the induction of DNA synthesis. We found that inhibition of protein kinase C (PKC) by Ro-31-8220 abolished ERK activation. Inhibition of phospholipase C (PLC) by U-73122 or of phosphoinositide (PI) 3-kinase by wortmannin partially reduced ERK activation. A similar partial inhibition was observed after treatment with
pertussis
toxin or PKC downregulation by phorbol ester treatment. The effect of wortmannin was additive with that produced by PKC downregulation but not with that due to
pertussis
toxin. These results suggest that both diacylglycerol-sensitive PKC, activated by PLC products, and diacylglycerol-insensitive PKC, possibly activated by a G(i)-PI 3-kinase-dependent process, are involved in
ET-1
-induced ERK activation. These two pathways were found to be activated mainly through the ET(A) receptor subtype.
ET-1
and phorbol ester stimulated Src activity in a PKC-dependent manner, both responses being abolished in the presence of Ro-31-8220. Inhibition of Src kinases by PP1 abrogated phorbol ester- and
ET-1
-induced ERK activation. Finally,
ET-1
activated Ras in a PP1- and Ro-31-8220-sensitive manner. Altogether, our results indicate that
ET-1
induces ERK activation in rat myometrial cells through the sequential stimulation of PKC, Src, and Ras.
...
PMID:ET-1 stimulates ERK signaling pathway through sequential activation of PKC and Src in rat myometrial cells. 1205 94
In striatal astrocytes, receptors for the vasoactive peptide endothelin (ET) are associated with several intracellular signalling pathways:
ET-1
increases the breakdown of phosphoinositides, induces a sustained influx of Ca2+ and inhibits the isoproterenol-induced formation of cAMP (Marin et al., J. Neurochem., 56, 1270 - 1275, 1991). In the present study, it will be shown that
ET-1
and ET-3 markedly stimulate the release of arachidonic acid (AA) from cultured astrocytes from the mouse striatum (EC50=3 and 7 nM for
ET-1
and ET-3, respectively), mesencephalon and cerebral cortex. The
ET-1
-evoked release of AA probably resulted from the activation of a phospholipase A2, since it required extracellular Ca2+ and was prevented by mepacrine but not by RHC 80267, an inhibitor of diacylglycerol lipase. The
ET-1
-induced release of AA was shown to be partially mediated by a guanine nucleotide-binding protein sensitive to
pertussis
toxin but not to cholera toxin. A cAMP-dependent process is not involved since the
ET-1
-evoked release of AA was not affected when cells were incubated with either isoproterenol or 8-bromo-cAMP. The
ET-1
-evoked release of AA could be mimicked by the co-application of a calcium ionophore and a protein kinase C activator. However, staurosporine, a potent inhibitor of protein kinase C, which blocked the release of AA induced by the combined application of ionomycin and phorbol 12-myristate 12-acetate (PMA), was without effect on the
ET-1
-evoked response, indicating that protein kinase C is not directly involved in the
ET-1
-induced release of AA. Furthermore, the responses induced by
ET-1
and by PMA were found to be additive. These results suggest that (1)
ET-1
receptors are coupled to the release of AA by a mechanism independent of both protein kinase C activation and the adenylate cyclase pathway, possibly via the activation of phospholipase A2, (2) different mechanisms (or different phospholipase A2 subtypes) are involved in the control of AA release in astrocytes.
...
PMID:Endothelin-evoked Release of Arachidonic Acid from Mouse Astrocytes in Primary Culture. 1210 34
Endothelins (
ET-1
, ET-2 and ET-3) are 21-amino acid vasoactive peptides that bind to G-protein-linked transmembrane receptors, ET-RA and ET-RB. As well as modulating vasoconstriction, endothelins regulate growth in several cell types and may also affect differentiation, inflammation and angiogenesis. Both macrophages and endothelins are found in areas of hypoxia in solid tumors and ET-2 expression may be modulated by hypoxia in some tumors. As the peptide structure of mature endothelins is similar to that of CXC chemokines, we asked if endothelins contribute to control of macrophage distribution in tumors. We found that ET-2 is a chemoattractant for macrophages and THP-1 monocytic cells, but not for freshly isolated monocytes. The chemotactic response to ET-2 shows a typical bell-shaped response curve. Experiments with endothelin receptor antagonists showed that migration to ET-2 is mediated via the ET-RB receptor. Moreover, monocytes do not express ET-RB. Chemotaxis towards ET-2 is via the MAPK pathway: p44 and p42 are phosphorylated when THP-1 cells are stimulated with ET-2, and the MAPKK inhibitor PD98059 stops chemotaxis. As with 'classical' chemokines, migration toET-2 is also inhibited by hypoxia and by
pertussis
toxin. As well as its chemotactic properties, ET-2 leads to activation of macrophages. In human breast tumors that express ET-2, endothelins and ET-RB expressing macrophages often co-localized. While shorter than 'classical' chemokines, ET-2 shares a similar peptide sequence with chemokines and may signal via a similar receptor and MAPK-mediated pathway. Furthermore, ET-2 expression by tumors may modulate the behavior of macrophages such that activated cells accumulate in areas of hypoxia.
...
PMID:Endothelin-2 is a macrophage chemoattractant: implications for macrophage distribution in tumors. 1220 23
Prostaglandins (PGs) play an important role in bone remodeling because eicosanoids are local mediators of bone metabolism, which can induce physiological and pathological responses of bone tissue. Biosynthesis of PGs is catalyzed by constitutively expressed PG endoperoxide G/H synthase (PGHS) 1 and by the inducible isoform PGHS-2. In MC3T3-E1 osteoblast-like cells, expression of PGHS-2 was shown by mechanical forces, cytokines, growth factors, and hormones. Recently, endothelin (ET) 1-stimulated PGHS-2 mRNA expression was described, leading to a burst in prostaglandin E2 (PGE2) production. In this study, we investigated
ET-1
-induced signal transduction pathway(s) involved in the PGHS-2 mRNA production. Time course of PGHS-2 mRNA expression reaching the maximum within 45 minutes is in good agreement with the concept of an immediate early gene product. Inhibition of phospholipase C (PLC), phospholipase D (PLD), phosphatidylinositol-3 kinase (PI-3-kinase), and protein kinase C (PKC) had no influence on PGHS-2 synthesis. Using specific blockers of tyrosine kinases indicated involvement of p38 MAPK but not p42/44 MAPK. By preloading cells with exoenzyme C3, we were able to show requirement of the Rho family of G proteins for p38 MAPK phosphorylation and PGHS-2 mRNA synthesis, whereas
pertussis
toxin (PTX) and cholera toxin (CTX) had no remarkable effect.
...
PMID:Involvement of Rho and p38 MAPK in endothelin-1-induced expression of PGHS-2 mRNA in osteoblast-like cells. 1236 81
Two Ca(2+)-mobilizing receptors expressed in lactotrophs, endothelin-A (ET(A)) and thyrotropin-releasing hormone (TRH), induce a rapid Ca(2+) release from intracellular stores and prolactin (PRL) secretion but differ in their actions during the sustained stimulation; TRH facilitates and
ET-1
inhibits voltage-gated calcium influx (VGCI) and PRL secretion. In
pertussis
toxin (PTX) treated cells,
ET-1
-induced inhibition of VGCI was abolished and the pattern of Ca(2+) signaling was highly comparable with that observed in TRH-stimulated cells. The addition of Cs(+), a relatively specific blocker of inward rectifier K(+) channels, mimicked the effect of PTX on the pattern of
ET-1
-induced sustained Ca(2+) signaling, but only in about 50% of cells, and did not affect agonist-induced inhibition of PRL secretion. Extracellular Cs(+) was also ineffective in altering the TRH-induced facilitation of VGCI and PRL secretion. Furthermore, apamin and paxilline, specific blockers of Ca(2+)-activated SKand BK-type K(+) channels, respectively; E-4031, a blocker of ether a-go-go K(+) channel; and linopirdine, a blocker of M-type K(+) channel, did not affect the agonist-specific patterns of calcium signaling and PRL secretion. These results suggest that
ET-1
inhibits VGCI through activation of Cs(+)-sensitive channels, presumably the Gi/o-controlled inward rectifier K(+) channels, and that this agonist also inhibits PRL release, but downstream of Ca(2+) influx. Further studies are required to identify the mechanism of sustained TRH-induced facilitation of VGCI and PRL secretion.
...
PMID:Dependence of prolactin release on coupling between Ca(2+) mobilization and voltage-gated Ca(2+) influx pathways in rat lactotrophs. 1266 67
Endothelin-1 has dual vasoactive effects, mediating vasoconstriction via ETA receptor activation of vascular smooth muscle cells and vasorelaxation via ETB receptor activation of endothelial cells. Although it is commonly accepted that endothelin-1 binding to endothelial cell ETB receptors stimulates nitric oxide (NO) synthesis and subsequent smooth muscle relaxation, the signaling pathways downstream of ETB receptor activation are unknown. Here, using a model in which we have utilized isolated primary endothelial cells, we demonstrate that
ET-1
binding to sinusoidal endothelial cell ETB receptors led to increased protein kinase B/Akt phosphorylation, endothelial cell nitric-oxide synthase (eNOS) phosphorylation, and NO synthesis. Furthermore, eNOS activation was not dependent on tyrosine phosphorylation, and pretreatment of endothelial cells with
pertussis
toxin as well as overexpression of a dominant negative G-protein-coupled receptor kinase construct that sequesters betagamma subunits inhibited Akt phosphorylation and NO synthesis. Taken together, the data elucidate a G-protein-coupled receptor signaling pathway for ETB receptor-mediated NO production and call attention to the absolute requirement for heterotrimeric G-protein betagamma subunits in this cascade.
...
PMID:Endothelin-1 activates endothelial cell nitric-oxide synthase via heterotrimeric G-protein betagamma subunit signaling to protein jinase B/Akt. 1452 27
We have studied the role of endothelins (
ET-1
, ET-2 and ET-3) and ET receptors (ET-RA and ET-RB) in the invasive capacity of breast tumor cells, which express
ET-1
and ET-2 as well as ET-RA and ET-RB. Of five human breast tumor cell lines tested, all expressed mRNAs for
ET-1
, ET-2, and ET-RB. ET-RA mRNA was expressed by four of five tumor cell lines. Breast tumor cells migrated toward
ET-1
and ET-2 but not toward ET-3. Chemotaxis involved signaling via both receptors, and a
pertussis
toxin-sensitive p42/p44 mitogen-activated protein kinase (MAPK)-mediated pathway that could be inhibited by MAPK kinase (MEK)1/2 antagonists. Chemotaxis toward ETs did not involve p38 or stress-activated protein kinase (SAPK)/Jun N-terminal kinase (JNK) and was not inhibited by hypoxia. Incubation of tumor cells with ET-2 also increased chemotaxis toward the chemokines CXCL12 and CCL21. As well as inducing chemotaxis of tumor cells,
ET-1
and ET-2 increased tumor cell invasion through Matrigel. Furthermore, stimulation of macrophage/tumor cell cocultures with ETs led to increased matrix metalloproteinase (MMP)-2 and -9 production by macrophages and a marked increase in invasion of tumor cells. Antagonism of either ET-RA or ET-RB decreased the invasion seen in ET-stimulated cocultures, as did a broad-spectrum MMP inhibitor. Immunohistochemical staining of human breast tumor sections showed increased ET and ET receptor protein expression by tumor cells in invasive ductal carcinoma compared with normal breast tissue or ductal carcinoma in situ. Furthermore, tumor cell ET and receptor expression was stronger at the invasive margin of invasive ductal carcinomas, in the lymphovascular space, and in lymph node metastases. ET expression often colocalized with ET-RB expression in all neoplastic tissue indicating a possible autocrine action of ETs. We suggest that expression of ETs and their receptors by human breast tumors, particularly in conjunction with a high macrophage infiltrate, may have a role in the progression of breast cancer and the invasion of tumor cells.
...
PMID:A role for endothelin-2 and its receptors in breast tumor cell invasion. 1505 99
During sympathetic neurotransmitter release, there is evidence for differential modulation of cotransmitter release by endothelin (ET)-1. Using nerve growth factor (NGF)-differentiated PC12 cells, the effects of
ET-1
on K(+)-stimulated release of ATP, dopamine (DA), and neuropeptide Y (NPY) were quantified using high-pressure liquid chromatography or radioimmunoassay.
ET-1
, in a concentration-dependent manner, inhibited the release of ATP, but not DA and NPY. Preincubation with the ET(A/B) antagonist, PD 142893 (N-acetyl-beta-phenyl-D-Phe-Leu-Asp-Ile-Ile-Trp), reversed the inhibitory effect of
ET-1
on ATP release, which remained unaffected in the presence of the ET(A)-specific antagonist BQ123 [cyclo(D-Asp-Pro-D-Val-Leu-D-Trp)]. The ET(B) agonists, sarafotoxin 6c (Cys-Thr-Cys-Asn-Asp-Met-Thr-Asp-Glu-Glu-Cys-Leu-Asn-Phe-Cys-His-Gln-Asp-Val-Ile-Trp), BQ 3020 (N-acetyl-[Ala(11,15)]-
endothelin 1
fragment 6-21Ac-Leu-Met-Asp-Lys-Glu-Ala-Val-Tyr-Phe-Ala-His-Leu-Asp-IIe-IIe-Trp), and IRL 1620 (N-succinyl-[Glu(9), Ala(11,15)]-
endothelin 1
fragment 8-21Suc-Asp-Glu-Glu-Ala-Val-Tyr-Phe-Ala-His-Leu-Asp-Ile-Ile-Trp), decreased K(+)-stimulated release of ATP in a dose-dependent manner, and this effect was reversed by the ET(B) antagonists RES 701-1 [cyclic (Gly1-Asp9) (Gly-Asn-Trp-His-Gly-Thr-Ala-Pro-Asp-Trp-Phe-Phe-Asn-Tyr-Tyr-Trp)] and BQ 788 (N-[N-[N-[(2,6-dimethyl-1-piperidinyl)carbonyl]-4-methyl-l-leucyl]-1-(methoxycarbonyl)-D-tryptophyl]-D-norleucine sodium salt). Preincubation of PC12 cells with
pertussis
toxin reversed the
ET-1
-induced inhibition of the K(+)-evoked ATP release. Real-time intracellular calcium level recordings were performed on PC-12 cell suspensions, and
ET-1
induced a dose-dependent decrease in the K(+)-evoked calcium levels. Nifedipine, the L-type voltage-dependent Ca(2+) channel antagonist, caused inhibition of the K(+)-stimulated ATP release, but the N-type Ca(2+) channel antagonist, omega-conotoxin GVIA, did not reverse the effect on ATP release. These data suggest that
ET-1
modulates the release of ATP via the ET(B) receptor and its associated G(i/o) G-protein through attenuation of the influx of extracellular Ca(2+) through L-type channels.
...
PMID:Endothelin (ET)-1-induced inhibition of ATP release from PC-12 cells is mediated by the ETB receptor: differential response to ET-1 on ATP, neuropeptide Y, and dopamine levels. 1568 74
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