Calcium-dependent release of arachidonic acid in response to purinergic receptor activation in airway epithelium

1994 ◽  
Vol 266 (2) ◽  
pp. C406-C415 ◽  
Author(s):  
E. R. Lazarowski ◽  
R. C. Boucher ◽  
T. K. Harden
Keyword(s):  
Arachidonic Acid ◽  
Inositol Phosphate ◽  
Purinergic Receptor ◽  
Receptor Activation ◽  
Normal Donor ◽  
Maximal Effect ◽  
Airway Epithelial ◽  
Arachidonic Acid Release ◽  
Receptor Agonists ◽  
Acid Release

The effect of purinergic receptor agonists on arachidonic acid release was investigated in [3H]arachidonic acid-prelabeled human airway epithelial cells. Exposure of bronchial epithelial BEAS39 cells to extracellular ATP resulted in a marked release of unesterified [3H]arachidonic acid with maximal effect observed within 60-90 s. [3H]diacylglycerol and [3H]phosphatidic acid accumulated in parallel with [3H]arachidonic acid. ATP-stimulated [3H]arachidonic acid release with a K0.5 of 9 +/- 2 microM and UTP was equipotent; no effect was observed with P2Y- or P2X-purinergic receptor agonists or with adenosine. Similar results were obtained with primary cultures of normal human nasal epithelium, CF/T43 and HBE1 airway epithelial cell lines derived from a cystic fibrosis patient and from a normal donor, respectively, and HT-29 human colon carcinoma cells. ATP stimulated inositol phosphate formation in BEAS39 cells with a concentration dependence identical to that for [3H]arachidonic acid release. The effect of ATP on both [3H]arachidonic acid release and inositol phosphate formation was equally inhibited by pertussis toxin. The Ca2+ ionophore A-23187 mimicked the effects of ATP or UTP on arachidonic acid release, and a marked inhibitory effect was observed with thapsigargin. The protein kinase C inhibitor staurosporine partially inhibited ATP-stimulated [3H]arachidonic acid release. These data are consistent with the hypothesis that phospholipase A2 activation is secondary to P2U-purinergic receptor stimulation of D-myoinositol 1,4,5-trisphosphate production and calcium mobilization from intracellular stores.

Norepinephrine stimulates arachidonic acid release from vascular smooth muscle via activation of cPLA2

1998 ◽  
Vol 274 (4) ◽  
pp. C1129-C1137 ◽  
Author(s):  
Edward F. LaBelle ◽  
Erzsebet Polyak
Keyword(s):  
Arachidonic Acid ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Adrenergic Receptors ◽  
Phospholipase A ◽  
Maximal Effect ◽  
Arachidonic Acid Release ◽  
Tail Artery ◽  
Acid Release ◽  
Arachidonate Release

The mechanism of agonist-activated arachidonate release was studied in segments of rat tail artery. Tail artery segments were prelabeled with [3H]arachidonate and then stimulated with norepinephrine (NE), and the radioactivity of the extracellular medium was determined. NE stimulated arachidonate release from the tissue without increasing arachidonic acid levels within cellular cytosol or crude membranes. About 90% of the extracellular radioactivity was shown to be unmetabolized arachidonate by TLC. Arachidonic acid release was not inhibited by the removal of the endothelium from the artery. NE exerted a half-maximal effect at a concentration of 0.2 μM. NE-stimulated arachidonate release was not inhibited by blockers of phospholipase C (U-73122), diacylglycerol lipase (RHC-80267), secretory phospholipase A2 (manoalide), calcium-insensitive phospholipase A2 (HELSS), or β-adrenergic receptors (propranolol). NE-stimulated arachidonic acid release was inhibited by blockers of cytosolic phospholipase A2(cPLA2) (AACOCF3), α1-adrenergic receptors (prazosin), and specific G proteins (pertussis toxin). This indicated that NE stimulated arachidonate release from vascular smooth muscle via activation of α-adrenergic receptors, either Gi or Go, and cPLA2. NE-activated arachidonic acid release from vascular smooth muscle may play a role in force generation by the tissue. Perhaps arachidonic acid extends the effect of NE on one specific smooth muscle cell to its nearby neighbor cells.

scholarly journals Mastoparan, a novel mitogen for Swiss 3T3 cells, stimulates pertussis toxin-sensitive arachidonic acid release without inositol phosphate accumulation.

1991 ◽  
Vol 113 (4) ◽  
pp. 943-950 ◽  
Author(s):  
J Gil ◽  
T Higgins ◽  
E Rozengurt
Keyword(s):  
Arachidonic Acid ◽  
Growth Factor ◽  
Dna Synthesis ◽  
Pertussis Toxin ◽  
Inositol Phosphate ◽  
Dependent Manner ◽  
Arachidonic Acid Release ◽  
3T3 Cells ◽  
Acid Release ◽  
Swiss 3T3

Mastoparan, a basic tetradecapeptide isolated from wasp venom, is a novel mitogen for Swiss 3T3 cells. This peptide induced DNA synthesis in synergy with insulin in a concentration-dependent manner; half-maximum and maximum responses were achieved at 14 and 17 microM, respectively. Mastoparan also stimulated DNA synthesis in the presence of other growth promoting factors including bombesin, insulin-like growth factor-1, and platelet-derived growth factor. The synergistic mitogenic stimulation by mastoparan can be dissociated from activation of phospholipase C. Mastoparan did not stimulate phosphoinositide breakdown, Ca2+ mobilization or protein kinase C-mediated phosphorylation of a major cellular substrate or transmodulation of the epidermal growth factor receptor. In contrast, mastoparan stimulated arachidonic acid release, prostaglandin E2 production, and enhanced cAMP accumulation in the presence of forskolin. These responses were inhibited by prior treatment with pertussis toxin. Hence, mastoparan stimulates arachidonic acid release via a pertussis toxin-sensitive G protein in Swiss 3T3 cells. Arachidonic acid, like mastoparan, stimulated DNA synthesis in the presence of insulin. The ability of mastoparan to stimulate mitogenesis was reduced by pertussis toxin treatment. These results demonstrate, for the first time, that mastoparan stimulates reinitiation of DNA synthesis in Swiss 3T3 cells and indicate that this peptide may be a useful probe to elucidate signal transduction mechanisms in mitogenesis.

scholarly journals Phospholipid metabolism, calcium flux, and the receptor-mediated induction of chemotaxis in rabbit neutrophils.

1982 ◽  
Vol 93 (3) ◽  
pp. 690-697 ◽  
Author(s):  
D L Bareis ◽  
F Hirata ◽  
E Schiffmann ◽  
J Axelrod
Keyword(s):  
Arachidonic Acid ◽  
Calcium Influx ◽  
Calcium Ionophore ◽  
Receptor Activation ◽  
Calcium Flux ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Arachidonic Acid Release ◽  
Chemotactic Peptide ◽  
Acid Release

Rabbit neutrophils were stimulated with the chemotactic peptide fMet-Leu-Phe in the presence of the methyltransferase inhibitors homocysteine (HCYS) and 3-deazaadenosine (3-DZA). HCYS and 3-DZA inhibited chemotaxis, phospholipid methylation, and protein carboxymethylation in a dose-dependent manner. The chemotactic peptide-stimulated release of [14C]arachidonic acid previously incorporated into phospholipid was also partially blocked by the methyltransferase inhibitors. Stimulation by fMet-Leu-Phe or the calcium ionophore A23187 caused release of arachidonic acid but not of previously incorporated [14C]-labeled linoleic, oleic, or stearic acids. Unlike the arachidonic acid release caused by fMet-Leu-Phe, release stimulated by the ionophore could not be inhibited by HCYS and 3-DZA, suggesting that the release was caused by a different mechanism or by stimulating a step after methylation in the pathway from receptor activation to arachidonic acid release. Extracellular calcium was required for arachidonic acid release, and methyltransferase inhibitors were found to partially inhibit chemotactic peptide-stimulated calcium influx. These results suggest that methylation pathways may be associated with the chemotactic peptide receptor stimulation of calcium influx and activation of a phospholipase A2 specific for cleaving arachidonic acid from phospholipids.

PGE2 release by bradykinin in human airway smooth muscle cells: involvement of cyclooxygenase-2 induction

1997 ◽  
Vol 273 (6) ◽  
pp. L1132-L1140 ◽  
Author(s):  
Linhua Pang ◽  
Alan J. Knox
Keyword(s):  
Arachidonic Acid ◽  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Arachidonic Acid Release ◽  
Human Airway Smooth Muscle ◽  
Short Term ◽  
Human Airway ◽  
Acid Release ◽  
Cox 2

Prostanoids may be involved in bradykinin (BK)-induced bronchoconstriction in asthma. We investigated whether cyclooxygenase (COX)-2 induction was involved in prostaglandin (PG) E2 release by BK in cultured human airway smooth muscle (ASM) cells and analyzed the BK receptor subtypes responsible. BK stimulated PGE2release, COX activity, and COX-2 induction in a concentration- and time-dependent manner. It also time dependently enhanced arachidonic acid release. In short-term (15-min) experiments, BK stimulated PGE2 generation but did not increase COX activity or induce COX-2. In long-term (4-h) experiments, BK enhanced PGE2 release and COX activity and induced COX-2. The long-term responses were inhibited by the protein synthesis inhibitors cycloheximide and actinomycin D and the steroid dexamethasone. The effects of BK were mimicked by the B2-receptor agonist [Tyr(Me)8]BK, whereas the B1 agonist des-Arg9-BK was weakly effective at high concentrations. The B2antagonist HOE-140 potently inhibited all the effects, but the B1 antagonist des-Arg9,(Leu8)-BK was inactive. This study is the first to demonstrate that BK can induce COX-2. Conversion of increased arachidonic acid release to PGE2 by COX-1 is mainly involved in the short-term effect, whereas B2 receptor-related COX-2 induction is important in the long-term PGE2 release.

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