Demonstration of calcium-dependent phospholipase A2 activity in membrane preparation of rabbit neutrophils. Absence of activation by fMet-Leu-Phe, phorbol 12-myristate 13-acetate and A-kinase

Matsumoto, Tadashi; Tao, Weng; Sha'afi, R.I.

doi:10.1042/bj2500343

Cited by 28 publications

(26 citation statements)

References 22 publications

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“…Thus, some effects of TPA were suggested to result from direct membrane perturba tion, but not the activation of protein kinase C (13,14). In contrast, our results indicate that TPA-induced enhance ment of catecholamine secretion in digitonin-permeabil ized adrenal medullary cells is due to the activation of protein kinase C. The concentration of calphostin C used in the present study is higher than that reported in the in vitro experiment (9).…”

Section: Nicotiniccontrasting

confidence: 55%

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Calphostin C, a Potent and Specific Inhibitor of Protein Kinase C, Reduces Phorbol Ester-Induced but Not Primary Ca2+-Induced Catecholamine Secretion from Digitonin-Permeabilized Bovine Adrenal Medullary Cells

Isosaki

Minami

Nakashima

1994

Japanese Journal of Pharmacology

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ABSTRACT-Calphostin C, a protein kinase C inhibitor, reduced phorbol ester-induced enhancement of catecholamine secretion but not primary Ca"-induced secretion from digitonin-permeabilized bovine adrenal medullary cells, indicating that this compound selectively inhibited protein kinase C-dependent secretion.Keywords: Adrenal medulla, Protein kinase C, Secretion Nicotinic agonist-induced catecholamine secretion from bovine adrenal medullary cells is triggered by a rise in the cytosolic Ca2+ concentration as a consequence of an increased permeability of the plasma membrane to extracellular Ca 2+. The sequence of the events between a rise in the cytosolic Ca 21 concentration and exocytotic catecholamine secretion remains poorly understood. Sev eral lines of evidence indicate that Ca 2+-activated, phos pholipid-dependent protein kinase (protein kinase C) is involved in the process of exocytosis (1-3). Ca 21 influx into the cells causes both the translocation of protein kinase C molecules to the membrane and diacylglycerol accumulation from the breakdown of phosphoinositides, which results in the activation of protein kinase C (2). Active phorbol esters that can replace diacylglycerol in stimulating protein kinase C also potentiate Ca 2+-in duced catecholamine secretion from electropermeabilized and digitonin-permeabilized adrenal medullary cells (1, 3). Moreover, a variety of protein kinase C inhibitors such as neomycin, spermine, calmidazolium and polymyx in B have been reported to depress not only phorbol ester induced enhancement of catecholamine secretion but also Ca2+-induced secretion (4), suggesting that protein ki nase C plays an essential role in secretion. In contrast, pro tein kinase inhibitors such as staurosporine and K-252a, a pseudosubstrate peptide of protein kinase C, and mild treatment with trypsin were found to reduce only catechol amine secretion enhanced by phorbol ester without effect on Ca" -induced secretion (5 8). Calphostin C has been reported to be a novel and potent inhibitor of protein kinase C and about 1000 times more specific to protein kinase C than other protein kinases such as cAMP-depend ent protein kinase and tyrosine-specific protein kinase (9). Thus, the effect of calphostin C on Ca 2+-dependent and phorbol ester-dependent catecholamine secretion from digitonin-permeabilized bovine adrenal medullary cells was examined in the present study.Bovine adrenal medullary cells were isolated by sequen tial digestion of adrenal medullary slices with collagenase as reported previously (10), purified by a Percoll (Phar macia, Uppsala, Sweden) gradient and maintained as monolayer cultures in Eagle's minimal essential medium containing 10°70 heat-inactivated calf serum, 100 units/ml penicillin, 100 pg/ml streptmycin, 0.3 pg/ml amphoteri cin B and 10 pM cytosine arabinoside. The cells were plat ed in 24-well cluster plates at a density of 8 x 105 cells/well. The cultured cells were washed with 0.5 ml of sodium glutamate medium consisting of 150 mM monoso dium glutamate and 10 mM Na PIPES (pH...

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Section: Nicotiniccontrasting

confidence: 55%

“…H-7, a protein kinase C inhibitor, has been reported to fail to inhibit TPA-induced enhancement of [3H]-arachi donic acid release caused by the Ca2+ ionophore A23187 in rabbit neutrophils (13,14). Thus, some effects of TPA were suggested to result from direct membrane perturba tion, but not the activation of protein kinase C (13,14).…”

Section: Nicotinicmentioning

confidence: 99%

Calphostin C, a Potent and Specific Inhibitor of Protein Kinase C, Reduces Phorbol Ester-Induced but Not Primary Ca2+-Induced Catecholamine Secretion from Digitonin-Permeabilized Bovine Adrenal Medullary Cells

Isosaki

Minami

Nakashima

1994

Japanese Journal of Pharmacology

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“…Cyto- solic and secretory PLA2s have been described in a number of cells, including neutrophils (Traynor & Authi, 1981;Balsinde et al, 1988;Ramesha & Ives, 1993), monocytes (Wightman et al, 1981;Ulevitch et al, 1988;Clark et al, 1990) and platelets (Matsumoto et al, 1988;Kramer et al, 1989;Takayama et al, 1991). PLA2 enzymes may be involved in cell proliferation and signal transduction as well as in the pathogenesis of disease processes such as inflammation (Mukherjee et al, 1994).…”

Section: Discussionmentioning

confidence: 99%

Involvement of secretory phospholipase A₂ activity in the zymosan rat air pouch model of inflammation

Payá

Terencio

Ferrándiz

et al. 1996

British J Pharmacology

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1 In the zymosan rat air pouch model of inflammation we have assessed the time dependence of phospholipase A2 (PLA2) accumulation in the inflammatory exudates as well as cell migration, myeloperoxidase activity, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels. 2 A significant increase in PLA2 activity was detected in 1,200 g supernatants of exudates 8 h after injection of zymosan into rat air pouch. This event coincided with peaks in cell accumulation (mainly neutrophils) and myeloperoxidase activity in exudates and was preceded by a rise in eicosanoid levels. 3 This enzyme (without further purification) behaved as a secretory type II PLA2 with an optimum pH at 7-8 units, lack of selectivity for arachidonate release and dependence on mM calcium concentrations for maximal activity. 4 The PLA2 inhibitors manoalide and scalaradial inhibited this enzyme activity in vitro in a concentration-dependent manner. Scalaradial also inhibited zymosan stimulated myeloperoxidase release in vitro.5 Injection of the marine PLA2 inhibitor scalaradial together with zymosan into the pouch at doses of 0.5, 1 and 5 umol per pouch resulted in a dose-dependent inhibition of PLA2 activity in exudates collected 8 h later. Myeloperoxidase levels and cell migration were also decreased, while eicosanoid levels were not modified. 6 Colchicine administration to rats prevented infiltration and decreased PLA2 levels in the 8 h zymosan-injected air pouch. 7 These results indicate that during inflammatory response to zymosan in the rat air pouch a secretory PLA2 activity is released into the exudates. The source of this activity is mainly the neutrophil which migrates into the pouch. 8 Scalaradial exerts anti-inflammatory effects in the zymosan air pouch.

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“…This suggests that PMA produces its effect in part by direct membrane perturbation. A similar idea has been advanced for the potentiating effect of PMA on stimulated arachidonic acid release (22,23).…”

Section: Discussionmentioning

confidence: 93%

Phorbol 12-myristate 13-acetate inhibits binding of leukotriene B4 and platelet-activating factor and the responses they induce in neutrophils: site of action.

Yamazaki¹,

Gómez‐Cambronero²,

Durstin³

et al. 1989

Proc. Natl. Acad. Sci. U.S.A.

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The addition of the platelet-activating factor (PAF) to neutrophils causes an increase in cytoskeletal actin, a rise in the intracellular concentration of free calcium, release of arachidonic acid, and the synthesis of PAF. The PAF synthesis in human neutrophils stimulated by PAF is greatly potentiated by the human granulocyte-macrophage colonystimulating factor. Incubation of human neutrophils with the tumor copromoter phorbol 12-myristate 13-acetate (PMA) for 3 min prior to the addition of the stimulus inhibits all these responses produced by PAF. The inhibition is prevented when the cells are incubated with protein kinase C inhibitors such as 1-(5-isoquinolinesulfonyl)-2-methylpiperazine for 5 min prior to the addition of PMA. The rise in the intracellular concentration of free calcium in human neutrophils stimulated with leukotriene B4 is also inhibited by PMA, and this inhibition is prevented by protein kinase C inhibitors such as staurosporine. Unlike PMA, the inactive ester 4a-phorbol 12,13-didecanoate has no inhibitory effect on the stimulated rise in the intracellular concentration of free calcium. The binding of either PAF or leukotriene B4 to intact cells is inhibited by PMA. The most important rinding of the present studies is that PMA interferes with the binding of PAF and leukotriene B4 to their respective receptors. Whether PMA inhibits the binding of these lipid mediators by activating protein kinase C or by perturbing the membrane directly remains to be elucidated.Since its recent discovery, the role of protein kinase C (PKC) in initiating and modulating various cell functions has been under intense examination by several investigators using various cell types, including neutrophils. In neutrophils, PKC has been implicated in superoxide generation and possibly other cell functions (1-5). In addition to diacylglycerol, which is the natural stimulus, the tumor copromoter phorbol 12-myristate 13-acetate (PMA) binds to and activates PKC.Recently, it has been suggested that in several systems, including neutrophils, PKC activation plays both agonist and antagonist roles (6, 7). The wide occurrence of the PKC system in many cell types raises the possibility that one of the major physiological functions of the stimulation of PKC is to protect against cellular overstimulation. With respect to the agonist role of PKC, the site or sites of the excitationresponse sequence which may be affected are not known (7).The present studies were undertaken to examine three questions. First, does PMA inhibit human neutrophil responses produced by lipid mediators such as leukotriene B4 (LTB4) and platelet-activating factor (PAF)? Second, is the inhibition, if present, mediated by PKC activation? Third, what site in the excitation-response sequence is affected by PMA?MATERIALS AND METHODS Preparation of Cells. Human neutrophils were isolated from peripheral blood on Ficoll/Hypaque gradients as described by English and Andersen (8). Rabbit neutrophils (4-hr exudate) were collected and washed as described previou...

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Demonstration of calcium-dependent phospholipase A2 activity in membrane preparation of rabbit neutrophils. Absence of activation by fMet-Leu-Phe, phorbol 12-myristate 13-acetate and A-kinase

Cited by 28 publications

References 22 publications

Calphostin C, a Potent and Specific Inhibitor of Protein Kinase C, Reduces Phorbol Ester-Induced but Not Primary Ca2+-Induced Catecholamine Secretion from Digitonin-Permeabilized Bovine Adrenal Medullary Cells

Calphostin C, a Potent and Specific Inhibitor of Protein Kinase C, Reduces Phorbol Ester-Induced but Not Primary Ca2+-Induced Catecholamine Secretion from Digitonin-Permeabilized Bovine Adrenal Medullary Cells

Involvement of secretory phospholipase A₂ activity in the zymosan rat air pouch model of inflammation

Phorbol 12-myristate 13-acetate inhibits binding of leukotriene B4 and platelet-activating factor and the responses they induce in neutrophils: site of action.

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Demonstration of calcium-dependent phospholipase A2 activity in membrane preparation of rabbit neutrophils. Absence of activation by fMet-Leu-Phe, phorbol 12-myristate 13-acetate and A-kinase

Cited by 28 publications

References 22 publications

Calphostin C, a Potent and Specific Inhibitor of Protein Kinase C, Reduces Phorbol Ester-Induced but Not Primary Ca2+-Induced Catecholamine Secretion from Digitonin-Permeabilized Bovine Adrenal Medullary Cells

Calphostin C, a Potent and Specific Inhibitor of Protein Kinase C, Reduces Phorbol Ester-Induced but Not Primary Ca2+-Induced Catecholamine Secretion from Digitonin-Permeabilized Bovine Adrenal Medullary Cells

Involvement of secretory phospholipase A2 activity in the zymosan rat air pouch model of inflammation

Phorbol 12-myristate 13-acetate inhibits binding of leukotriene B4 and platelet-activating factor and the responses they induce in neutrophils: site of action.

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Involvement of secretory phospholipase A₂ activity in the zymosan rat air pouch model of inflammation