Mechanisms of increased endothelial prostanoid synthesis in response to nigericin in the newborn pig cerebral circulation

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Abstract

In the newborn cerebral circulation, vasodilator effects of hypercapnia are associated with the rapid stimulation of endothelial prostanoid (PG) synthesis. Effects of hypercapnia on PG synthesis can be reproduced by nigericin (K+/H+ ionophore) which rapidly decreases the pHi in cultured endothelial cells from newborn pig cerebral microvessels. We investigated the role of protein phosphorylation in the activation of PG synthesis by nigericin. In endothelial cells pretreated with the protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate (PMA), 10-5M nigericin increased PG synthesis 10- to 20-fold, while PMA or nigericin alone had moderate effects (1.5-2 fold). In cells pretreated with the protein tyrosine phosphatase (PTP) inhibitors, sodium orthovanadate and phenylarsine oxide, nigericin also greatly amplified prostanoid synthesis (10- to 20-fold). The protein tyrosine kinase (PTK) inhibitors, genistein, tyrphostin47, and tyrphostin25, abolished effects of nigericin in control and PMA-treated cells suggesting the involvement of both serine/threonine and tyrosine protein phosphorylation. We investigated the rapid effects of nigericin on phospholipase A2 (PLA2), a key enzyme in endothelial prostanoid synthesis. Nigericin alone did not alter PLA2 activity measured as arachidonic acid (AA) release from [3H]AA-loaded mdomethacin-pretreated cells. However, in cells pretreated with PMA or sodium orthovanadate, nigericin greatly increased AA release. These data suggest that cPLA2, a PLA2 subtype that could be posttranslationally activated by phosphorylation, is involved in the changes in PG synthesis caused by nigericin and, possibly, hypercapnia.

Original languageEnglish (US)
JournalFASEB Journal
Volume12
Issue number5
StatePublished - Mar 20 1998

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Cerebrovascular Circulation
nigericin
Nigericin
prostaglandins
Prostaglandins
neonates
Swine
swine
synthesis
hypercapnia
Phosphorylation
phospholipase A2
Hypercapnia
Phospholipases A2
Acetates
arachidonic acid
acetates
Arachidonic Acid
Vanadates
protein phosphorylation

All Science Journal Classification (ASJC) codes

  • Agricultural and Biological Sciences (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology

Cite this

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title = "Mechanisms of increased endothelial prostanoid synthesis in response to nigericin in the newborn pig cerebral circulation",
abstract = "In the newborn cerebral circulation, vasodilator effects of hypercapnia are associated with the rapid stimulation of endothelial prostanoid (PG) synthesis. Effects of hypercapnia on PG synthesis can be reproduced by nigericin (K+/H+ ionophore) which rapidly decreases the pHi in cultured endothelial cells from newborn pig cerebral microvessels. We investigated the role of protein phosphorylation in the activation of PG synthesis by nigericin. In endothelial cells pretreated with the protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate (PMA), 10-5M nigericin increased PG synthesis 10- to 20-fold, while PMA or nigericin alone had moderate effects (1.5-2 fold). In cells pretreated with the protein tyrosine phosphatase (PTP) inhibitors, sodium orthovanadate and phenylarsine oxide, nigericin also greatly amplified prostanoid synthesis (10- to 20-fold). The protein tyrosine kinase (PTK) inhibitors, genistein, tyrphostin47, and tyrphostin25, abolished effects of nigericin in control and PMA-treated cells suggesting the involvement of both serine/threonine and tyrosine protein phosphorylation. We investigated the rapid effects of nigericin on phospholipase A2 (PLA2), a key enzyme in endothelial prostanoid synthesis. Nigericin alone did not alter PLA2 activity measured as arachidonic acid (AA) release from [3H]AA-loaded mdomethacin-pretreated cells. However, in cells pretreated with PMA or sodium orthovanadate, nigericin greatly increased AA release. These data suggest that cPLA2, a PLA2 subtype that could be posttranslationally activated by phosphorylation, is involved in the changes in PG synthesis caused by nigericin and, possibly, hypercapnia.",
author = "Elena Parfenova and L. Balabanova and Charles Leffler",
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T1 - Mechanisms of increased endothelial prostanoid synthesis in response to nigericin in the newborn pig cerebral circulation

AU - Parfenova, Elena

AU - Balabanova, L.

AU - Leffler, Charles

PY - 1998/3/20

Y1 - 1998/3/20

N2 - In the newborn cerebral circulation, vasodilator effects of hypercapnia are associated with the rapid stimulation of endothelial prostanoid (PG) synthesis. Effects of hypercapnia on PG synthesis can be reproduced by nigericin (K+/H+ ionophore) which rapidly decreases the pHi in cultured endothelial cells from newborn pig cerebral microvessels. We investigated the role of protein phosphorylation in the activation of PG synthesis by nigericin. In endothelial cells pretreated with the protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate (PMA), 10-5M nigericin increased PG synthesis 10- to 20-fold, while PMA or nigericin alone had moderate effects (1.5-2 fold). In cells pretreated with the protein tyrosine phosphatase (PTP) inhibitors, sodium orthovanadate and phenylarsine oxide, nigericin also greatly amplified prostanoid synthesis (10- to 20-fold). The protein tyrosine kinase (PTK) inhibitors, genistein, tyrphostin47, and tyrphostin25, abolished effects of nigericin in control and PMA-treated cells suggesting the involvement of both serine/threonine and tyrosine protein phosphorylation. We investigated the rapid effects of nigericin on phospholipase A2 (PLA2), a key enzyme in endothelial prostanoid synthesis. Nigericin alone did not alter PLA2 activity measured as arachidonic acid (AA) release from [3H]AA-loaded mdomethacin-pretreated cells. However, in cells pretreated with PMA or sodium orthovanadate, nigericin greatly increased AA release. These data suggest that cPLA2, a PLA2 subtype that could be posttranslationally activated by phosphorylation, is involved in the changes in PG synthesis caused by nigericin and, possibly, hypercapnia.

AB - In the newborn cerebral circulation, vasodilator effects of hypercapnia are associated with the rapid stimulation of endothelial prostanoid (PG) synthesis. Effects of hypercapnia on PG synthesis can be reproduced by nigericin (K+/H+ ionophore) which rapidly decreases the pHi in cultured endothelial cells from newborn pig cerebral microvessels. We investigated the role of protein phosphorylation in the activation of PG synthesis by nigericin. In endothelial cells pretreated with the protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate (PMA), 10-5M nigericin increased PG synthesis 10- to 20-fold, while PMA or nigericin alone had moderate effects (1.5-2 fold). In cells pretreated with the protein tyrosine phosphatase (PTP) inhibitors, sodium orthovanadate and phenylarsine oxide, nigericin also greatly amplified prostanoid synthesis (10- to 20-fold). The protein tyrosine kinase (PTK) inhibitors, genistein, tyrphostin47, and tyrphostin25, abolished effects of nigericin in control and PMA-treated cells suggesting the involvement of both serine/threonine and tyrosine protein phosphorylation. We investigated the rapid effects of nigericin on phospholipase A2 (PLA2), a key enzyme in endothelial prostanoid synthesis. Nigericin alone did not alter PLA2 activity measured as arachidonic acid (AA) release from [3H]AA-loaded mdomethacin-pretreated cells. However, in cells pretreated with PMA or sodium orthovanadate, nigericin greatly increased AA release. These data suggest that cPLA2, a PLA2 subtype that could be posttranslationally activated by phosphorylation, is involved in the changes in PG synthesis caused by nigericin and, possibly, hypercapnia.

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