Phospholipase A activity associated with membranes of human polymorphonuclear leucocytes

Franson, Richard C.; Weiss, Jerrold; Martin, Luisa; Spitznagel, J K; Elsbach, Peter

doi:10.1042/bj1670839

Cited by 70 publications

(13 citation statements)

References 10 publications

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“…Qualitatively similar Ca2+-dependent AH activity has also been identified in examinations of plasma membrane fractions prepared from IM (20). These findings are consistent with studies in other tissues which have also demonstrated Ca2+-dependent AH activity associated with microsomes and plasma membranes (4,13,(22)(23)(24). Addition of hypertonic urea to the enzyme assay mixture, suppressed Ca2+-responsive particulate AH of IM (Fig.…”

Section: Discussionsupporting

confidence: 80%

Renal inner medullary prostaglandin synthesis. A calcium-calmodulin-dependent process suppressed by urea.

Craven¹,

Studer²,

DeRubertis³

1981

J. Clin. Invest.

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A B S T R A C T Previous studies have dlemonstrated that hyperosmolar NaCl and miiannitol stimulate immunoreactive prostaglandin E (iPGE) production by slices of inner medulla (IM), wherease urea inhibits this process. In the present study, the roles of Ca21 and calmodulin in the control of PCE synthesis in IM and the basis for the differential actions of solutes were examined. A23187 increased ['4C]arachidonate (AA) release and iPGE accumulatioin in the presence but not in the absence of media Ca2+ whereas stimulation by hypertonic NaCl or mannitol was well expressed with Ca2+ or in Ca2+-free buffer containing 2 mM EGTA. Hypertonic urea and trifluoperazine (TFP), an inhibitor of actions of the Ca2+-CaM complex, suppressed increases in [14C]AA release and iPGE induced by A23187, NaCl, or mannitol. By contrast, increases in iPGE in response to exogenous AA were not altered by urea or TFP. Ca2+ (25-100 uM) increased acyl hydrolase (AH) activity in EGTA washed (4°C) 100,000g particulate fractions of IM threefold, thereby restoring AH activity to the higher basal values of particulate fractions not washed with EGTA. This action of Ca2+ was blocked by hypertonic urea or TFP, whereas AH activity was not influenced by NaCl or mannitol in the presence or absence of Ca2 . In contrast to their effects on AH activity, hypertonic urea and TFP did not alter conversion of AA to PGE2, PGF2a, or PGD2 by IM microsomal fractions. Ca2+-induced increases in particulate AH were blunted after partial depletion of endogenous CaM-like activity.Ca2+ action was restored by addition of purified exogenous CaM, but not by addition of other small acidic proteins, including troponin C. The findings support a role for CaM in the regulation of PGE synthesis in the IM at the level of Ca2+-responsive AH activity. They further imply that urea suppresses PGE

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Section: Discussionsupporting

confidence: 80%

Renal inner medullary prostaglandin synthesis. A calcium-calmodulin-dependent process suppressed by urea.

Craven¹,

Studer²,

DeRubertis³

1981

J. Clin. Invest.

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“…cAMP-activated lipases have been described in adipose tissue, and increased lipolysis has correlated better with the degree of protein phosphorylation than with cAMP levels (32). Phospholipases also have been detected in rabbit alveolar macrophages (33) and in human neutrophil granules (34), but in neither instance has activation by cAMP been examined. In addition, phospholipase activity has been implicated in the alterations of membrane lipids induced by phagocytosis (35) and in the release of arachadonic acid from mitogen-stimulated lymphocytes (36).…”

Section: Discussionmentioning

confidence: 94%

Loss of Fc receptor activity after culture of human monocytes on surface-bound immune complexes. Mediation by cyclic nucleotides.

Ragsdale¹,

Arend²

1980

The Journal of Experimental Medicine

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Human monocytes cultured on surface-bound immune complexes exhibited a loss of ability to form rosettes with IgG-sensitized sheep erythrocytes (EA). This loss was not a result of inhibition of Fc receptors by solubilized complexes nor of release of soluble factors by the cells. Loss of EA rosetting was not prevented by culture of monocytes at 4 degrees C, or by treatment with colchicine, cytochalasin B, or local anethetic agents. These results suggested that the loss was not secondary to capping or interiorization of Fc receptors. The results of other studies indicated that the Fc receptors were not damaged by lysosomal enzymes or oxygen radicals. Maintenance of EA rosetting ability of monocytes cultured on surface-bound immune complexes was seen after a 3-h preincubation of the cells in 100 mM 2-deoxy-D-glucose (2dG). A similar preincubation in ATP or in 8-bromoadenosine 3':5'-cyclic monophosphoric acid plus the phosphodiesterase inhibitor methyl isobutyl xanthine led to a partial loss of EA rosetting of cells on plain fibrin and to a partial reversal of the effects of 2dG seen with cells on complexes. We conclude that EA rosetting of monocytes cultured on surface-bound immune complexes is reduced by cyclic nucleotide-mediated effects on Fc receptor number or function.

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“…A rich source of inflammatory phospholipase A2 is the ascitic fluid that can be elicited in the peritoneal cavity of rabbits [2] and which has been purified to homogeneity (31. A soluble phospholipase A2 has also been described and purified from synovial fluids of patients with rheumatoid arthritis [4, 51.…”

mentioning

confidence: 99%

Release of phospholipase A₂ activity from rat vascular smooth muscle cells mediated by cAMP

Pfeilschifter

Pignat

Märki

et al. 1989

European Journal of Biochemistry

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Primary cultures of smooth muscle cells (SMC) derived from rat aorta release a phospholipase A2 activity into the culture medium. Phospholipase A2 activity was determined with [I -'4C]oleate-labelled Escherichiu coli as substrate. The enzyme has a neutral pH optimum and the activity is critically dependent on the free calcium concentration, with significant activity in the micromolar range of free calcium. Treatment of SMC with the p agonist salbutamol, forskolin or cholera toxin, which all activate adenylate cyclase and increase intracellular CAMP concentration, increase the release of phospholipase A2 activity in a dose-dependent manner. Likewise, the addition of the membrane-permeable CAMP analogues, (Sp)-adenosine 3',5'-[thiolphosphate and N6,0-2'-dibutyryladenosine 3',5'-phosphate, enhance the release of phospholipase A2 activity from SMC in a dosedependent manner. There is a lag period of about 4 h before a significant secretion of phospholipase A2 can be detected under basal, as well as under stimulated conditions. The forskolin analogue 1,9-dideoxyforskolin, which is inactive as a stimulator of adenylate cyclase, has no effect on phospholipase A2 secretion. Likewise, the potent vasoconstrictive peptide angiotensin I1 activates inositol phospholipid turnover in SMC, but has no effect on phospholipase A2 release. Pretreatment of SMC with actinomycin D or cycloheximide completely suppresses basal and CAMP-stimulated secretion of phospholipase A2 activity, thus demonstrating that transcription and protein synthesis are necessary for enzyme release.High levels of extracellular phospholipase A2 have been described in association with local and systemic inflammatory processes in animals and man (for review see [I]). A rich source of inflammatory phospholipase A2 is the ascitic fluid that can be elicited in the peritoneal cavity of rabbits [2] and which has been purified to homogeneity (31. A soluble phospholipase A2 has also been described and purified from synovial fluids of patients with rheumatoid arthritis [4, 51. Soluble phospholipase A2 is secreted extracellularly from rabbit and rat chondrocytes, as well as from human synovial cells in response to interleukin 1 [6 -91 and tumour necrosis factor[9], two potent inflammatory mediators. Furthermore, the release of phospholipase A2 activity has been described from rabbit peritoneal neutrophils in response to the chemotactic peptide Met-Leu-Phe [I 01, from resident mouse peritoneal macrophages in response to zymosan [ll] and from rat platelets on stimulation with thrombin [12]. Extracellular phospholipase A2 is proinflammatory and vasoactive, and mediates hyperemia and a marked inflammatory reaction when injected intracutaneously into rabbits [14]. The present report presents data demonstrating that SMC spontaneously Correspondence to J. Pfeilschifter,

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Phospholipase A activity associated with membranes of human polymorphonuclear leucocytes

Cited by 70 publications

References 10 publications

Renal inner medullary prostaglandin synthesis. A calcium-calmodulin-dependent process suppressed by urea.

Renal inner medullary prostaglandin synthesis. A calcium-calmodulin-dependent process suppressed by urea.

Loss of Fc receptor activity after culture of human monocytes on surface-bound immune complexes. Mediation by cyclic nucleotides.

Release of phospholipase A₂ activity from rat vascular smooth muscle cells mediated by cAMP

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Phospholipase A activity associated with membranes of human polymorphonuclear leucocytes

Cited by 70 publications

References 10 publications

Renal inner medullary prostaglandin synthesis. A calcium-calmodulin-dependent process suppressed by urea.

Renal inner medullary prostaglandin synthesis. A calcium-calmodulin-dependent process suppressed by urea.

Loss of Fc receptor activity after culture of human monocytes on surface-bound immune complexes. Mediation by cyclic nucleotides.

Release of phospholipase A2 activity from rat vascular smooth muscle cells mediated by cAMP

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Release of phospholipase A₂ activity from rat vascular smooth muscle cells mediated by cAMP