Effect of signal transduction pathways on the action of thapsigargin on rat mast cells

Alfonso, A.; Botana, Manuel; Vieytes, Mercedes R.; Louzao, M. Carmen; Botana, Luís M.

doi:10.1016/0006-2952(94)90310-7

Cited by 24 publications

(26 citation statements)

References 35 publications

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“…After checking the ionic modulation on the Na + /H + -exchanger activity we studied the effect of Ca 2+ , cAMP and PKC on the activity of the exchanger. Evidence shows a functional relationship between calcium and pH [10,28]. We checked the effect of extracellular and intracellular calcium in the activity of the Na + /H + exchanger.…”

Section: Resultsmentioning

confidence: 99%

“…The rate constant in control conditions was 0.52 B 0.06 pHi units/min, while in the presence of 0.1 ÌM thapsigargin this value increased to 0.75 B 0.07 pHi units/min. It has been reported that the activation of PKC by the phorbol esther PMA increases the sensitivity of mast cells to calcium [10]. Therefore, we checked under the same conditions the effect of the activation of PKC by using PMA (100 ng/ml).…”

Section: Resultsmentioning

confidence: 99%

“…In rat mast cells, the PKC-mediated activation of the Na + /H + antiporter is calcium-dependent, although calcium does not have any direct effect on the exchanger. Similarly, activation of protein kinase A by increasing cAMP levels, or the inhibition of protein phosphatases 1 and 2A by okadaic acid [10], show a pattern of pHi changes in rat mast cells which are different from those changes reported in other cellular models [8,18]. Therefore, the signaling pathways functionally linked to Na + /H + activation remains controversial and poorly characterized.…”

Section: Introductionmentioning

confidence: 89%

“…[6][7][8][9], and its activity is modulated by several transduction pathways which are probably originated through the activation of G proteins [10,11]. Depending on the cell type, the activation or inhibition of different intracellular transduction pathways results in the activation or inhibition of the Na + /H + exchanger.…”

Section: Introductionmentioning

confidence: 99%

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Sodium, PMA and Calcium Play an Important Role on Intracellular pH Modulation in Rat Mast Cells

Alfonso¹,

Botana²,

Vieytes³

et al. 1998

Cell Physiol Biochem

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In a series of experiments aimed to understand the signaling pathways that regulate intracellular pH (pHi) in rat mast cells, the effect of different intracellular mechanisms on the activity of the Na⁺/H⁺ exchanger was studied. After promoting an artificial acidification with sodium propionate we determined the variations on pHi rate recovery. pHi was measured with the dye 2,7-bis(carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester. We studied the effect that the inhibition of some cellular exchangers with different drugs induced on pHi. When the Na⁺/H⁺ exchanger was inhibited in the presence of amiloride, the recovery rate constant was twofold smaller than the control value. After the recovery, the final pH was lower than the initial value when the cells were treated either with amiloride or with 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (an anionic antiport inhibitor). No effect was observed when the Na⁺/K⁺-ATPase or the Na⁺/Ca²⁺ exchanger were inhibited. The suppression of intracellular and extracellular calcium did not induced any change in pHi. The addition of thapsigargin, an activator of capacitative calcium influx, or the phorbol esther 12-O-tetradecanoylphorbol-13-acetate (PMA), a protein kinase C (PKC) activator, increased the activity of the antiporter. Both effects were abrogated by inhibition of the Na⁺/K⁺-ATPase with ouabain. The increase in cAMP levels did not affect the effect of PMA on pHi recovery, but it blocked the effect of thapsigargin. Our results indicate that rat mast cells regulate pHi by the combination of some anionic exchanger and the Na⁺/H⁺ antiporter. And also that the modulation of this exchanger is the consequence of the connection between different intracellular mechanisms, Na⁺/K⁺-ATPase-PKC-calcium, among which cAMP seems not to have a direct role.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sodium, PMA and Calcium Play an Important Role on Intracellular pH Modulation in Rat Mast Cells

Alfonso¹,

Botana²,

Vieytes³

et al. 1998

Cell Physiol Biochem

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“…Furthermore, compound 48/80-induced pHi increase was completely abolished by staurosporine and HMA, but histamine release was not. It has been suggested that one of the roles of PKC is to alkalinize the cytosol to favour calcium release in rat peritoneal mast cells (Alfonso et al, 1994b). Similarly, it has previously been shown that the hydrolysis of inositol phospholipids in combination with an increase in…”

Section: Phi Regulation and Histamine Releasementioning

confidence: 95%

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1996

British J Pharmacology

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1 The purpose of this study was to compare the actions of phorbol 12-myristate 13-acetate (PMA) and ionomycin on Na+/H+ exchange activation and histamine release to that of compound 48/80 in order to study the possible relationship between pHi and secretion of histamine in rat peritoneal mast cells.2 Resting pHi in mast cells suspended in a bicarbonate-free physiological salt solution amounted to 6.73 + 0.05 (mean + s.d., n = 52). 3 PMA (20 nM) induced a substantial but rather slow increase in pHi. This response was very sensitive to inhibition by staurosporine, very sensitive to inhibition by 5-(N,N-hexamethylene)amiloride (HMA), insensitive to the absence of extracellular calcium (without EGTA), and sensitive to partial depletion of intracellular calcium with EGTA.4 Ionomycin (1 gM) induced a biphasic change in pHi that was sensitive to inhibition by HMA, insensitive to staurosporine. In the absence of extracellular calcium using EGTA, the biphasic response disappeared, leaving only a slow, and diminished change in pHi. 5 The effects of ionomycin and PMA on pHi were additive.6 Addition of the secretagogue compound 48/80 (1 ug ml-') increased pHi substantially, ApHi amounting to 0.29 + 0.05 pH-units (n = 4). The biphasic pHi-response was insensitive to the absence of extracellular calcium (without EGTA). The initial fast response in pHi was, however, inhibited by HMA, not staurosporine. 7 The finding that staurosporine and HMA each inhibited approximately half of the compound 48/80-induced pHi-response, whereas both inhibitors completely abolished the compound 48/80-induced pHiresponse seems to indicate that two independent pathways for the activation of the Na+/H+ exchange were stimulated by compound 48/80. 8 The histamine release induced via both PKC activation (using PMA) and calcium (using ionomycin) were much larger than the sum of each activation pathway, whereas in the absence of extracellular calcium using EGTA, the histamine release in response to PMA and ionomycin was completely abolished. 9 The compound 48/80-induced histamine release was partially sensitive to inhibition by HMA ( t30% inhibition) and partially sensitive to inhibition by staurosporine (; 50% inhibition). Preincubation with staurosporine and HMA before stimulation with compound 48/80 showed the same degree of inhibition as observed after staurosporine alone, even though this combination of drugs completely inhibited the pHi-response. Furthermore, compound 48/80-induced histamine release was not dependent on the presence of extracellular calcium (with and without EGTA). 10 In spite of the similarities in second messenger pathways for pH, regulation and histamine release, it is, however, not very likely that these two processes are directly related. It is, however, possible, that an increase in pHi plays a permissive, rather than an essential role for histamine release in rat peritoneal mast cells. This hypothesis was supported by the finding that preincubation with the Na+/H+ exchangeinhibitor HMA inhibited 30% of the compound 48/80-i...

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PKC and cAMP positively modulate alkaline‐induced exocytosis in the human mast cell line HMC‐1

Pernas-Sueiras¹,

Alfonso²,

Vieytes³

et al. 2006

J of Cellular Biochemistry

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We study in HMC-1 the activation process, measured as histamine release. We know that ammonium chloride (NH(4)Cl) and ionomycin release histamine, and the modulatory role of drugs targeting protein kinase C (PKC), adenosine 3',5'-cyclic monophosphate (cAMP), tyrosine kinase (TyrK) and phosphatidylinositol 3-kinase (PI3K) on this effect. We used Gö6976 (100 nM) and low concentration of GF 109203X (GF) (50 nM) to inhibit Ca(2+)-dependent PKC isozymes. For Ca(2+)-independent isozymes, we used 500 nM GF and 10 microM rottlerin (specifically inhibits PKCdelta). Phorbol 12-myristate 13-acetate (PMA) (100 ng/ml) was used to stimulate PKC, and genistein (10 microM) and lavendustin A (1 microM) as unspecific TyrK inhibitors. STI571 10 microM was used to specifically inhibit the activity of Kit, the receptor for stem cell factor, and 10 nM wortmannin as a PI3K inhibitor. Activation of PKC with PMA enhances histamine release in response to NH(4)Cl and ionomycin. PMA increases NH(4)Cl-induced alkalinization and ionomycin-induced Ca(2+) entry. Inhibition of PKCdelta strongly inhibits Ca(2+) entry elicited by ionomycin, but failed to modify histamine release. The effect of cAMP-active drugs was explored with the adenylate cyclase activator forskolin (30 microM), the inhibitor SQ22,536 (1 microM), the cAMP analog dibutyryl cAMP (200 microM), and the PKA blocker H89 (1 microM). Forskolin and dibutyryl cAMP do increase NH(4)Cl-induced alkalinization, and potentiate histamine release elicited by this compound. Our data indicates that alkaline-induced exocytosis is modulated by PKC and cAMP, suggesting that pH could be a modulatory signal itself.

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Effect of signal transduction pathways on the action of thapsigargin on rat mast cells

Cited by 24 publications

References 35 publications

Sodium, PMA and Calcium Play an Important Role on Intracellular pH Modulation in Rat Mast Cells

Sodium, PMA and Calcium Play an Important Role on Intracellular pH Modulation in Rat Mast Cells

Untitled

PKC and cAMP positively modulate alkaline‐induced exocytosis in the human mast cell line HMC‐1

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