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

In the human erythroleukemia cell line, HEL, prostaglandin E2 (PGE2) and the stable prostacyclin analogue, iloprost, increase cytosolic Ca2+ concentration ([Ca2+]i) via pertussis toxin-sensitive and -insensitive pathways. Unlike iloprost, the stable prostacyclin analogue cicaprost (ZK 96480), is devoid of agonistic properties at prostaglandin E2 receptors. We compared the effects of cicaprost, iloprost and PGE2 on [Ca2+]i in HEL cells. Cicaprost, iloprost and PGE2 were similarly potent to increase [Ca2+]i in HEL cells. However, unlike the effects of PGE2, those of the prostacyclin analogues were not inhibited by pertussis toxin. The prostaglandins studied increased [Ca2+]i through both mobilization from internal stores and Ca2+ influx from the extracellular space. Prostacyclin analogue- and PGE2-induced rises in [Ca2+]i were desensitized in a homologous manner. Additionally, there was cross-desensitization between cicaprost and iloprost, but not between the prostacyclin analogues and PGE2. Our data suggest that in HEL cells (i) cicaprost and iloprost act through prostacyclin receptors and (ii) that these receptors couple to pertussis toxin-insensitive heterotrimeric regulatory guanine nucleotide-binding proteins, (iii) resulting in an increase in [Ca2+]i by Ca2+ mobilization from internal stores and sustained influx.
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PMID:The prostacyclin analogues, cicaprost and iloprost, increase cytosolic Ca2+ concentration in the human erythroleukemia cell line, HEL, via pertussis toxin-insensitive G-proteins. 128 Apr 55

Thrombin is thought to stimulate responsive cells by cleaving cell-surface receptors coupled to intracellular second-messenger-generating enzymes via G-proteins. In order to understand this process better, we have examined the regulation of adenylate cyclase by thrombin in the megakaryoblastic HEL cell line and compared it with platelets. A notable difference was found. In HEL-cell membrane preparations, thrombin inhibited cyclic AMP (cAMP) formation by a pertussis-toxin-sensitive mechanism comparable with that observed in platelets. In contrast, when added to intact HEL cells, thrombin activated adenylate cyclase and caused an increase in cAMP formation synergistic with that produced by forskolin and prostaglandin I2. This increase, which was not seen with platelets, was accompanied by an increase in cAMP metabolism by phosphodiesterase. Like other responses to thrombin, the increase in cAMP formation required proteolytically active thrombin and was subject to homologous desensitization. An equivalent response could be evoked by the addition of a polypeptide, derived from the N-terminus of the thrombin receptor, that has been shown to activate the receptor. The effects of thrombin could not, however, be reproduced by the addition of phorbol ester and the Ca2+ ionophore, A23187, nor be prevented with inhibitors of arachidonate metabolism. Preincubation of the cells with adrenaline, which inhibited Gs-mediated activation of adenylate cyclase, or pertussis toxin, which inhibited phospholipase C activation, had no effect on thrombin-induced cAMP formation. These results suggest that thrombin can regulate cAMP formation by two different mechanisms. First, thrombin can inhibit adenylate cyclase in a Gi-dependent manner. This effect predominates in HEL-cell membrane preparations, as it does in platelets, but is not detectable when thrombin is added to intact HEL cells. Instead, in intact HEL cells thrombin activates adenylate cyclase. Although clearly receptor-mediated, this response does not appear to involve Gi, Gs, protein kinase C, eicosanoid formation or changes in the cytosolic Ca2+ concentration.
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PMID:Dual regulation of cyclic AMP formation by thrombin in HEL cells, a leukaemic cell line with megakaryocytic properties. 131 10

The pluripotent human erythroleukaemia cell line, HEL, possesses erythrocytic, megakaryocytic and macrophage-like properties. With respect to signal transduction, HEL cells have been used as a model system for platelets, but little attention has been paid to their phagocytic properties. We studied the effects of various receptor agonists on the intracellular free Ca2+ concentration ([Ca2+]i) in HEL cells. Thrombin, platelet-activating factor (PAF), ATP, UTP, prostaglandins E1 and E2 (PGE1 and PGE2), the PGE2 analogue sulprostone and the stable PGI2 analogues iloprost and cicaprost increased [Ca2+]i. ADP was less effective than ATP, and UDP was unable to increase [Ca2+]i. The increases in [Ca2+]i induced by thrombin, PAF, ATP, UTP, iloprost and cicaprost were pertussis toxin-insensitive, whereas the increases induced by PGE2 and sulprostone were completely inhibited by the toxin. The increase in [Ca2+]i induced by PGE1 was partially inhibited by pertussis toxin. PGE2 did not desensitize the increase in [Ca2+]i induced by iloprost, and vice versa. PGE1 desensitized the response to PGE2 and iloprost but not vice versa. Adrenaline potentiated the iloprost- but not the PGE2-induced rise in [Ca2+]i. The phorbol ester phorbol 12-myristate 13-acetate completely blocked the rise in [Ca2+]i induced by ATP and PGE1, whereas the increases induced by thrombin and PAF were only partially inhibited. Agonists increased [Ca2+]i through release from internal stores and sustained Ca2+ influx. Thrombin stimulated Mn2+ influx, which was blocked by Ni2+. Diltiazem, isradipine, gramicidin and 1-(beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl)-1H-imidazole hydrochloride (SK&F 96365) did not affect agonist-induced rises in [Ca2+]i. HEL cells contained substantial amounts of beta-glucuronidase which, however, could not be released, and they did not aggregate or generate superoxide. Our data suggest that: (1) HEL cells possess nucleotide receptors with properties similar to those of phagocytes; (2) they possess receptors for PGE2 and PGI2, and PGE1 is an agonist at both receptors; (3) agonist-induced increases in [Ca2+]i are mediated through pertussis toxin-sensitive as well as -insensitive signal transduction pathways; and (4) agonists increase [Ca2+]i by mobilization from internal stores and influx from the extracellular space through cation channels with properties similar to those of phagocytes and platelets.
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PMID:Receptor-mediated increases in cytosolic Ca2+ in the human erythroleukaemia cell line involve pertussis toxin-sensitive and -insensitive pathways. 131 May 89

The human erythroleukemia cell line (HEL) has been used as a model system for studying signal transduction processes as they might relate to platelet/megakaryocyte function. We were interested in examining the role of thrombin in the regulation of adenylyl cyclase in this cell line. As opposed to its predominantly inhibitory effects on cyclic AMP production in platelets or in membranes from HEL cells, our initial experiments in intact HEL cells revealed that thrombin markedly potentiated the cyclic AMP response to prostaglandin E1 (2.9 +/- 0.2-fold), prostacyclin (1.9 +/- 0.2-fold) and carbacyclin (2.5 +/- 0.5-fold), measured either by radioimmunoassay or by the [3H]adenine preloading procedure. Thrombin, although ineffective alone, also potentiated cyclic AMP production stimulated by vasoactive intestinal peptide (1.6 +/- 0.2-fold), cholera toxin (3.0 +/- 0.6-fold) and AIF4- (2.3 +/- 0.6-fold), but not by forskolin (0.9 +/- 0.1-fold). The thrombin effect 1) produced an increase in the efficacy of the prostaglandins with no change in potency; 2) was long-lived; 3) required the proteolytic activity of thrombin; 4) was insensitive to pertussis toxin; and 5) was at least partially mimicked by trypsin, extracellular ATP and UTP, platelet activating factor and activators of protein kinase C. Down-regulation of protein kinase C or pre-exposure to the protein kinase inhibitor staurosporine blocked the potentiating effect. Together, these results suggest that in HEL cells, the mechanism of thrombin potentiation of cyclic AMP production may involve alterations in the interaction between stimulatory guanine nucleotide binding protein and the catalytic subunit of adenylyl cyclase, possibly involving protein kinase C-mediated phosphorylation.
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PMID:Potentiation of cyclic adenosine monophosphate production by thrombin in the human erythroleukemia cell line, HEL. 133 12

Prostaglandin (PG) synthesis elicited by adrenergic transmitter in the vascular smooth muscle cells (VSMC) of rabbit aorta is primarily mediated through activation of alpha-2C and alpha-1A adrenergic receptors (ARs). We have now investigated and compared the signal transduction mechanisms involved in alpha-2C and alpha-1A AR-stimulated prostacyclin (PGI2) production, measured as 6-keto-PGF1 alpha, in vascular smooth muscle cells. Norepinephrine, methoxamine (an alpha-1 AR agonist) and UK-14304 (an alpha-2 AR agonist) enhanced 6-keto-PGF1 alpha production. UK-14304 and norepinephrine (in the presence of propranolol), but not methoxamine, reduced basal adenosine 2':3'-cyclic monophosphate (cyclic AMP) as well as forskolin- and isoproterenol-stimulated cyclic AMP accumulation. Forskolin and isoproterenol did not alter basal 6-keto-PGF1 alpha production and alpha AR agonist-induced 6-keto-PGF1 alpha production. Alpha-2C and alpha-1A AR-stimulated 6-keto-PGF1 alpha production was independent of cyclic AMP levels in vascular smooth muscle cells. Both alpha-2C and alpha-1A AR-stimulated 6-keto-PGF1 alpha production required extracellular Ca++. Pertussis toxin prevented inhibition of cyclic AMP accumulation and reduced 6-keto-PGF1 alpha production in response to AR agonists. Guanosine 5'-O-(3-thiotriphosphate) potentiated 6-keto-PGF1 alpha production induced by norepinephrine and UK-14304 but not by methoxamine, whereas at a higher Mg++ concentration (4 mM), guanosine 5'-O-(3-thiotriphosphate) potentiated 6-keto-PGF1 alpha production by all three agonists. In contrast, the effect of UK-14304 on cyclic AMP was prevented in the presence of 4 mM Mg++. These data suggest that the pertussis toxin-sensitive G protein(s) mediated the stimulation of PG synthesis by alpha-1A and alpha-2C AR activation and the decrease in cyclic AMP accumulation by alpha-2C AR activation.
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PMID:Comparison of signal transduction mechanisms of alpha-2C and alpha-1A adrenergic receptor-stimulated prostaglandin synthesis. 133 71

Fluid flow and several other agonists induce prostacyclin (PGI2) production in endothelial cells. G proteins mediate the response of a large number of hormones such as histamine, but the transduction pathway of the flow signal is unclear. We found that GDP beta S and pertussis toxin inhibited flow-induced prostacyclin production in human umbilical vein endothelial cells. In addition, flow potentiated the histamine-induced production of PGI2. This suggests that flow stimulates prostacyclin production via a pertussis toxin-sensitive G protein and modulates the stimulus-response coupling of other agonists.
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PMID:Flow-induced prostacyclin production is mediated by a pertussis toxin-sensitive G protein. 150 67

Attempts were made to identify prostaglandin (PG) receptors in rat myometrium, according to the differential rank order of potencies displayed by the natural PGs and their analogues, both at the level of second messenger generation and contraction. In estrogen-treated rat myometrium, PGs [iloprost = PGI2 greater than PGE2 much greater than 16,16-dimethyl (DM)-PGE2; sulprostone = misoprostol = 0] induced adenosine 3',5'-cyclic monophosphate generation, indicating the contribution of a PGI2 receptor. The generation of inositol phosphates was stimulated by PGs (PGF2 alpha greater than PGD2 much greater than PGE2 = DM-PGE2 much greater than iloprost greater than sulprostone = misoprostol = 0), reflecting a PGF2 alpha-receptor-mediated process, which was insensitive to pertussis toxin (PTX). Contractions caused by PGF2 alpha were closely correlated to PGF2 alpha-receptor activation associated with the phospholipase C pathway. By contrast, contractions evoked by PGE2, equally mimicked by sulprostone and misoprostol, were abolished by PTX and were independent of phospholipase C activation. In the pregnant myometrium (day 21), the latter PGE-receptor-mediated mechanism also contributed to contractions caused by PGE2 (less than microM concn). Phospholipase C activation was coupled not only to PGF2 alpha but also to PGE receptors and could be correlated with contractions induced by PGF2 alpha and PGE2 greater than microM concn). All PGs tested were coupled to inhibitory G protein-mediated adenylate cyclase inhibition, displaying an equipotency that did not allow characterization of the inhibitory PG receptors.
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PMID:Diverse prostaglandin receptors activate distinct signal transduction pathways in rat myometrium. 163 81

1. The addition of ATP to cultured bovine aortic endothelial cells induced the increase in intracellular free calcium concentration ([Ca2+]i) and thereby activated the sodium/proton exchanger and the prostacyclin production in a similar dose-dependent manner, as observed by the addition of ATP. 2. Other nucleoside triphosphates also activated the cells and the potency orders of the nucleotides were ATP greater than UTP greater than ITP greater than CTP greater than GTP for all the responses. 3. Pretreatment of the cells with UTP desensitized the response to ATP and the pretreatment of ATP desensitized the response to UTP. 4. The responses to ATP and UTP were inhibited by neither pertussis nor cholera toxin. 5. The receptor for UTP, however, may be a distinct pyrimidinoceptor different from the purinoceptor of the cells for ATP, because the 50% effective concentration of UDP was much larger than that of UTP, while ATP and ADP were essentially equipotent ligands to the endothelial cells.
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PMID:Activation of cultured bovine aortic endothelial cells by extracellular pyrimidine triphosphate. 164 13

Phospholipase D (PLD) can be activated by a variety of receptor agonists in different cell types. However, an effect of prostaglandins (PGs) on the activity of this enzyme has not been demonstrated previously. In this study, we found that PGE1 could stimulate PLD in human erythroleukemia cells, as measured by phosphatidylethanol formation, with an ED50 of 3.5 x 10(-7) M. PGE2 was also active, but other PGs including prostacyclin, PGD2 and PGF2, had no effect. PGE1 also elicited cyclic AMP production over the same concentration range that activated PLD. However, it is unlikely that cyclic AMP per se is responsible for PGE-induced PLD activation, because PLD could be substantially activated by PGE2 at concentrations (0.1-1 microM) which did not stimulate cyclic AMP production. Furthermore, no increase of phosphatidylethanol formation could be observed when cells were treated with other adenylyl cyclase-activating agents such as prostacyclin, forskolin and vasoactive intestinal peptide. In Ca+(+)-free medium, PLD activation by PGE1 and PGE2 was greatly reduced, indicating that their effect was through a Ca+(+)-dependent pathway. Pretreatment of cells with pertussis toxin abolished PGE1- and PGE2-stimulated PLD activity, implying the involvement of a G protein in the PGE-mediated signal transduction pathway. Our results not only indicate that E-series PGs may initiate some of their cellular effects through a novel pathway, activation of PLD, but also suggest that PGE-stimulated PLD activity in human erythroleukemia cells is Ca+(+)-dependent and is regulated via a pertussis toxin-sensitive G protein.
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PMID:Activation of phospholipase D by E-series prostaglandins in human erythroleukemia cells. 165 Aug 37

The role of guanine nucleotide-binding proteins in the induction of prostacyclin synthesis by stimulated endothelial cells is incompletely understood. We report that sodium fluoride (NaF), a potent activator of cellular guanine nucleotide-binding proteins, affected time- and concentration-dependent generation of prostacyclin (PGI2) by cultured human umbilical vein endothelial cells without evidence of cellular toxicity detected by 51Cr or lactate dehydrogenase release. PGI2 synthesis by NaF-stimulated endothelial cells was associated with increases in arachidonate release, phosphoinositide hydrolysis, generation of inositol phosphates, and accumulation of diacylglycerol. These responses to NaF, as well as alpha-thrombin-mediated responses, were not dependent upon the availability of extracellular free Ca2+ but were associated with the mobilization of stored intracellular Ca2+ detected by the luminescence of the photoprotein aequorin. Neither PGI2 synthesis nor Ca2+ responses following alpha-thrombin or NaF stimulation were inhibited by pretreatment of cells with the islet activating protein from Bordetella pertussis but were significantly attenuated by the G protein inhibitor GDP beta S in permeabilized cells. Our results are compatible with a model wherein NaF directly activates a phosphoinositidase-linked guanine nucleotide regulatory protein, Gp, in human umbilical vein endothelial cell monolayers. This activation results in phosphoinositide hydrolysis, Ca2+ mobilization, arachidonate release, and subsequent functional activation, assessed by PGI2 release. Biologically relevant agonists such as alpha-thrombin may exert their influence on arachidonate metabolism, in part, by promoting receptor-dependent activation of this G protein.
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PMID:Sodium fluoride induces phosphoinositide hydrolysis, Ca2+ mobilization, and prostacyclin synthesis in cultured human endothelium: further evidence for regulation by a pertussis toxin-insensitive guanine nucleotide-binding protein. 165 60


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