Cholesterol relieves the inhibitory effect of sphingomyelin on type II secretory phospholipase A2

Secretory type II phospholipase A2 (sPLA2) is inhibited by sphingomyelin (SPH); cholesterol either mixed with the model glycerophospholipid substrate or added to the assay medium as separated liposomes counteracts this inhibition efficiently. The inhibition of fatty acid release assayed by quantitative gas chromatography–MS is observed when SPH is added to erythrocyte membranes as the substrate instead of a readily hydrolysable phosphatidylethanolamine/phosphatidylserine model mixture. Hydrolysis of SPH by Staphylococcus aureus sphingomyelinase suppresses its inhibitory potency. The addition of cholesterol to SPH liposomes with a 1:1 stoichiometry relieves completely the inhibition of sPLA2 exerted by SPH. The mechanism of inhibition suggested by the binding assay is that sPLA2 binds with affinity to the SPH interface, after either phase segregation at the assay temperature or on the pure SPH liposomes added to the incubation medium. Cholesterol is shown to suppress the binding affinity of the enzyme for the SPH interface. A model for inhibition is suggested in which binding of the sphingosine moiety is competitive for sPLA2 (inhibition) or for cholesterol (release of the enzyme).

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Anti-sense to secretory type II phospholipase A2 inhibits fMLP induced arachidonic acid release in differentiated HL-60's

Biochemical Society Transactions ◽

10.1042/bst022136s ◽

1994 ◽

Vol 22 (2) ◽

pp. 136S-136S ◽

Cited By ~ 3

Author(s):

MOIRA A. ELMORE ◽

MARTIN J. CARRIER ◽

ROBERT H. DANIELS ◽

MAXINE E. HILL ◽

MICHAEL J. FINNEN

Keyword(s):

Arachidonic Acid ◽

Phospholipase A2 ◽

Type Ii ◽

Arachidonic Acid Release ◽

Secretory Type ◽

Acid Release

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Secretory Type II Phospholipase A2 Is Produced and Secreted by Epicardial Adipose Tissue and Overexpressed in Patients with Coronary Artery Disease

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2009-1222 ◽

2010 ◽

Vol 95 (2) ◽

pp. 963-967 ◽

Cited By ~ 60

Author(s):

Anne Dutour ◽

Vincent Achard ◽

Henrike Sell ◽

Nadia Naour ◽

Frederic Collart ◽

...

Keyword(s):

Coronary Artery Disease ◽

Adipose Tissue ◽

Coronary Artery ◽

Phospholipase A2 ◽

Epicardial Adipose Tissue ◽

Type Ii ◽

Secretory Type ◽

Artery Disease

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Modulation of human type II secretory phospholipase A2 by sphingomyelin and annexin VI

Biochemical Journal ◽

10.1042/bj3260227 ◽

1997 ◽

Vol 326 (1) ◽

pp. 227-233 ◽

Cited By ~ 52

Author(s):

Kamen KOUMANOV ◽

Claude WOLF ◽

Gilbert BÉREZIAT

Keyword(s):

Fatty Acids ◽

Polyunsaturated Fatty Acids ◽

Phospholipase A2 ◽

Cell Membranes ◽

Red Cell ◽

Type Ii ◽

Membrane Phospholipids ◽

Human Type ◽

Annexin Vi ◽

Hydrolysis Of

Conjectural results have been reported on the capacity of inflammatory secreted phospholipase A2 (sPLA2) to hydrolyse mammalian membrane phospholipids. Development of an assay based on the release of non-esterified fatty acids by the enzyme acting on the organized phospholipid mixture constituting the membrane matrix has led to the identification of two prominent effectors, sphingomyelin (SPH) and annexin. Recombinant human type II sPLA2 hydrolyses red-cell membrane phospholipids with a marked preference for the inner leaflet. This preference is apparently related to the high content of SPH in the outer leaflet, which inhibits sPLA2. This inhibition by SPH is specific for sPLA2. Cholesterol counteracts the inhibition of sPLA2 by SPH, suggesting that the SPH-to-cholesterol ratio accounts in vivo for the variable susceptibility of cell membranes to sPLA2. Different effects were observed of the presence of the non-hydrolysable D-α-dipalmitoyl phosphatidylcholine (D-DPPC), which renders the membranes rigid but does not inhibit sPLA2. Annexin VI was shown, along with other annexins, to inhibit sPLA2 activity by sequestering the phospholipid substrate. The present study has provided the first evidence that annexin VI, in concentrations that inhibit hydrolysis of purified phospholipid substrates, stimulated the hydrolysis of membrane phospholipids by sPLA2. The activation requires the presence of membrane proteins. The effect is specific for type II sPLA2 and is not reproducible with type I PLA2. The activation by annexin VI of sPLA2 acting on red cell membranes results in the preferential release of polyunsaturated fatty acids. It suggests that type II sPLA2, in conjunction with annexin VI, might be involved in the final step of endocytosis and/or exocytosis providing the free polyunsaturated fatty acids acting synergistically to cause membrane fusion.

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Hydrocortisone inhibits mucin secretion from guinea pig gallbladder

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1984.247.4.g427 ◽

1984 ◽

Vol 247 (4) ◽

pp. G427-G431 ◽

Cited By ~ 1

Author(s):

J. R. Moore ◽

B. S. Turner ◽

J. T. LaMont

Keyword(s):

Guinea Pig ◽

Phospholipase A2 ◽

Sodium Succinate ◽

Inhibitory Effect ◽

Membrane Phospholipids ◽

Mucin Secretion ◽

Basal Secretion ◽

Prostaglandin Release ◽

Hydrolysis Of

We studied the effects of hydrocortisone, an inhibitor of phospholipase A2, on the secretion of mucin and release of prostaglandins from guinea pig gallbladder explants. We measured mucin using [3H]glucosamine as a precursor and prostaglandins by radioimmunoassay of 6-keto-prostaglandin F1 alpha. Mucin secretion and prostaglandin release were studied under basal conditions and after arachidonate stimulation. Hydrocortisone sodium succinate reversibly inhibited basal secretion of mucin by 24% at 10(-5) M (P less than 0.05 compared with control) and 34% at 10(-4) M (P less than 0.01). Hydrocortisone, 10(-4) M, also reversibly inhibited arachidonate-stimulated secretion of mucin (P less than 0.01 compared with controls incubated with arachidonate alone). Release of prostaglandin F1 alpha was significantly inhibited by hydrocortisone under basal (P less than 0.01) and arachidonate-stimulated (P less than 0.01) conditions. The inhibitory effect of hydrocortisone was mediated by inhibition of hydrolysis of arachidonate from membrane phospholipids, suggesting that exogenous arachidonate is incorporated into membrane phospholipids prior to conversion to prostaglandins.

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Antibodies against oxidized LDL in relation to cell-adhesion molecules, secretory type II phospholipase A2 and carotid atherosclerosis

Atherosclerosis ◽

10.1016/s0021-9150(00)80875-8 ◽

2000 ◽

Vol 151 (1) ◽

pp. 192-193

Author(s):

J. Hulthe ◽

O. Wiklund ◽

E. Hurt-Camejo ◽

G. Bondjers

Keyword(s):

Cell Adhesion ◽

Phospholipase A2 ◽

Adhesion Molecules ◽

Cell Adhesion Molecules ◽

Carotid Atherosclerosis ◽

Oxidized Ldl ◽

Type Ii ◽

Secretory Type

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Relationship between arachidonic acid release and Ca2+-dependent exocytosis in digitonin-permeabilized bovine adrenal chromaffin cells

Biochemical Journal ◽

10.1042/bj2710571 ◽

1990 ◽

Vol 271 (3) ◽

pp. 571-574 ◽

Cited By ~ 27

Author(s):

A Morgan ◽

R D Burgoyne

Keyword(s):

Arachidonic Acid ◽

Phospholipase A2 ◽

Chromaffin Cells ◽

Nordihydroguaiaretic Acid ◽

Inhibitory Effect ◽

Arachidonic Acid Release ◽

Adrenal Chromaffin Cells ◽

Protein Kinase C Inhibitor ◽

Acid Release ◽

Adrenal Chromaffin

The relationship between Ca2(+)-dependent arachidonic acid release and exocytosis from digitonin-permeabilized bovine adrenal chromaffin cells was investigated. The phospholipase A2 inhibitors mepacrine, nordihydroguaiaretic acid and indomethacin had no effect on either arachidonic acid release or secretion. The phospholipase A2 activator melittin had no effect on secretion. The specific diacylglycerol lipase inhibitor RG80267 had no effect on secretion, but decreased basal arachidonic acid release to such an extent that the level of arachidonic acid in treated cells in response to 10 microM-Ca2+ was equivalent to that of control cells in the absence of Ca2+. Staurosporine, a protein kinase C inhibitor, was found to abolish Ca2(+)-dependent arachidonic acid release completely, but had only a slight inhibitory effect on Ca2(+)-dependent secretion. It is concluded that arachidonic acid is not essential for Ca2(+)-dependent exocytosis in adrenal chromaffin cells.

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Insulin-like growth factors counteract the effect of interleukin 1β on type II phospholipase A2 expression and arachidonic acid release by rabbit articular chondrocytes

FEBS Letters ◽

10.1016/0014-5793(94)80171-1 ◽

1994 ◽

Vol 340 (1-2) ◽

pp. 51-55 ◽

Cited By ~ 21

Author(s):

F. Berenbaum ◽

G. Thomas ◽

S. Poiraudeau ◽

G. Béréziat ◽

M.T. Corvol ◽

...

Keyword(s):

Arachidonic Acid ◽

Growth Factors ◽

Phospholipase A2 ◽

Articular Chondrocytes ◽

Interleukin 1Β ◽

Type Ii ◽

Arachidonic Acid Release ◽

Acid Release ◽

Rabbit Articular Chondrocytes ◽

Insulin Like Growth Factors

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Phospholipase A2 from bee venom increases poly(I:C)-induced activation in human keratinocytes

International Immunology ◽

10.1093/intimm/dxaa005 ◽

2020 ◽

Vol 32 (6) ◽

pp. 371-383 ◽

Cited By ~ 3

Author(s):

Akina Nakashima ◽

Susumu Tomono ◽

Tatsuya Yamazaki ◽

Masanori Inui ◽

Naoko Morita ◽

...

Keyword(s):

Phospholipase A2 ◽

Human Keratinocytes ◽

Skin Inflammation ◽

Inhibitory Effect ◽

Bee Venom ◽

Poly I:C ◽

Membrane Phospholipids ◽

Polycytidylic Acid ◽

Mitogen Activated Protein ◽

Hydrolysis Of

Abstract Bee venom (BV) induces skin inflammation, characterized by erythema, blisters, edemas, pain and itching. Although BV has been found to have an inhibitory effect on toll-like receptors (TLRs), we here show that BV enhances keratinocyte responses to polyinosinic-polycytidylic acid [poly(I:C)], a ligand for TLR3. Our results revealed that the enhanced TLR activity was primarily induced by secretory phospholipase A2 (sPLA2), a component of BV (BV-sPLA2). PLA2 mediates the hydrolysis of membrane phospholipids into lysophospholipids and free fatty acids. We demonstrated that BV-sPLA2 increased the intracellular uptake of poly(I:C), phosphorylation of the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs), and poly(I:C)-mediated interleukin 8 production in human keratinocytes. We further showed that the enzymatic activity of BV-sPLA2 was essential for the increased uptake of poly(I:C). These findings suggest that BV-sPLA2 may induce a modification of the cell membrane structure, leading to enhanced poly(I:C) uptake in keratinocytes. BV-sPLA2 might be able to promote wound healing by enhancing TLR3 responses.

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Hypoxia induces changes in phospholipase A2 in rat proximal tubules: evidence for multiple forms

AJP Renal Physiology ◽

10.1152/ajprenal.1995.269.6.f846 ◽

1995 ◽

Vol 269 (6) ◽

pp. F846-F853 ◽

Cited By ~ 3

Author(s):

K. H. Choi ◽

C. L. Edelstein ◽

P. Gengaro ◽

R. W. Schrier ◽

R. A. Nemenoff

Keyword(s):

Phospholipase A2 ◽

Molecular Mass ◽

Cell Injury ◽

Gel Filtration ◽

Proximal Tubules ◽

Pla2 Activity ◽

Extracellular Medium ◽

Fatty Acid Release ◽

Acid Release ◽

Mass Form

Increased free fatty release during hypoxia is believed to contribute to cell injury. This phenomenon is likely to be mediated through activation of specific isoforms of phospholipase A2 (PLA2). In this study, PLA2 enzymatic activity was measured in cell-free extracts prepared from rat renal proximal tubules. Both soluble and membrane-associated PLA2 activity were detected. All PLA2 activity detected during normoxia was Ca2+ dependent. Fractionation of cytosolic extracts by gel filtration revealed three peaks of PLA2 activity. Exposure of tubules to hypoxia resulted in stable activation of soluble PLA2 activity, which correlated with disappearance of the highest molecular mass form (> 100 kDa) and appearance of a low-molecular-mass form (approximately 15 kDa) of PLA2. Hypoxia also resulted in release of a low-molecular-mass form of PLA2 into the extracellular medium. Pretreatment of tubules with glycine before hypoxia blocked this release of PLA2 but not activation of soluble PLA2 activity. These studies provide direct evidence for PLA2 activation during hypoxia and suggest that multiple mechanisms regulate free fatty acid release associated with hypoxia injury.

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