Differences in positional esterification of 14,15-epoxyeicosatrienoic acid in phosphatidylcholine of porcine coronary artery endothelial and smooth muscle cells

Xiang Fang, Neal L. Weintraub, Arthur A. Spector

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Epoxyeicosatrienoic acids (EETs) are readily incorporated into phospholipids of smooth muscle cells (SMC) and endothelial cells (EC). Incorporation of EETs into intact porcine coronary arteries potentiates EC-dependent relaxation, but not vasorelaxation induced by agents that act solely on SMC. To explore the potential mechanisms responsible for this difference, porcine coronary artery SMC and EC preloaded with [3H]14,15-EET were treated with calcium ionophore A23187. Although the amount of EET incorporated into EC and SMC was similar, A23187 stimulated a five-fold increase in release of radioactivity from EC, but only a 21% increase in release from SMC. Thin layer chromatography (TLC) examination of cell lipids demonstrated that >70% of the incorporated radioactivity was present in phosphatidylcholine (PC) in both SMC and EC. After treatment of EC PC with PLA2, TLC analysis indicated that ≅75% of radioactivity was present as free EET, and 25% of radioactivity was present as lyso-PC. Therefore, most of the 14,15-EET was esterified into the sn-2 position of PC in EC. However, in SMC, ≅70% of radioactivity was present as lyso-PC after PLA2 treatment, indicating that the EET was predominately esterified into the sn-1 position. In contrast, all of the 14,15-EET was esterified into the sn-2 position of PI in both EC and SMC. These results suggest that the preferential incorporation of 14,15-EET into the sn-1 position of PC in SMC may help to explain the greater retention of the compound in SMC, while incorporation into the sn-2 position of PC in EC may facilitate agonist-induced 14,15-EET release and potentiation of EC-dependent porcine coronary artery relaxation.

Original languageEnglish (US)
Pages (from-to)33-42
Number of pages10
JournalProstaglandins and Other Lipid Mediators
Volume71
Issue number1-2
DOIs
StatePublished - Apr 2003
Externally publishedYes

Fingerprint

Esterification
Endothelial cells
Phosphatidylcholines
Smooth Muscle Myocytes
Muscle
Coronary Vessels
Swine
Endothelial Cells
Cells
Radioactivity
Thin layer chromatography
Calcimycin
Thin Layer Chromatography
14,15-epoxy-5,8,11-eicosatrienoic acid
Calcium Ionophores
Vasodilation
Phospholipids
Lipids

Keywords

  • Endothelium
  • Epoxyeicosatrienoic acid
  • Esterification
  • Phospholipid
  • Smooth muscle

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology

Cite this

@article{6269683bc9f8424ca5047a6601576548,
title = "Differences in positional esterification of 14,15-epoxyeicosatrienoic acid in phosphatidylcholine of porcine coronary artery endothelial and smooth muscle cells",
abstract = "Epoxyeicosatrienoic acids (EETs) are readily incorporated into phospholipids of smooth muscle cells (SMC) and endothelial cells (EC). Incorporation of EETs into intact porcine coronary arteries potentiates EC-dependent relaxation, but not vasorelaxation induced by agents that act solely on SMC. To explore the potential mechanisms responsible for this difference, porcine coronary artery SMC and EC preloaded with [3H]14,15-EET were treated with calcium ionophore A23187. Although the amount of EET incorporated into EC and SMC was similar, A23187 stimulated a five-fold increase in release of radioactivity from EC, but only a 21{\%} increase in release from SMC. Thin layer chromatography (TLC) examination of cell lipids demonstrated that >70{\%} of the incorporated radioactivity was present in phosphatidylcholine (PC) in both SMC and EC. After treatment of EC PC with PLA2, TLC analysis indicated that ≅75{\%} of radioactivity was present as free EET, and 25{\%} of radioactivity was present as lyso-PC. Therefore, most of the 14,15-EET was esterified into the sn-2 position of PC in EC. However, in SMC, ≅70{\%} of radioactivity was present as lyso-PC after PLA2 treatment, indicating that the EET was predominately esterified into the sn-1 position. In contrast, all of the 14,15-EET was esterified into the sn-2 position of PI in both EC and SMC. These results suggest that the preferential incorporation of 14,15-EET into the sn-1 position of PC in SMC may help to explain the greater retention of the compound in SMC, while incorporation into the sn-2 position of PC in EC may facilitate agonist-induced 14,15-EET release and potentiation of EC-dependent porcine coronary artery relaxation.",
keywords = "Endothelium, Epoxyeicosatrienoic acid, Esterification, Phospholipid, Smooth muscle",
author = "Xiang Fang and Weintraub, {Neal L.} and Spector, {Arthur A.}",
year = "2003",
month = "4",
doi = "10.1016/S0090-6980(03)00002-9",
language = "English (US)",
volume = "71",
pages = "33--42",
journal = "Prostaglandins and Other Lipid Mediators",
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TY - JOUR

T1 - Differences in positional esterification of 14,15-epoxyeicosatrienoic acid in phosphatidylcholine of porcine coronary artery endothelial and smooth muscle cells

AU - Fang, Xiang

AU - Weintraub, Neal L.

AU - Spector, Arthur A.

PY - 2003/4

Y1 - 2003/4

N2 - Epoxyeicosatrienoic acids (EETs) are readily incorporated into phospholipids of smooth muscle cells (SMC) and endothelial cells (EC). Incorporation of EETs into intact porcine coronary arteries potentiates EC-dependent relaxation, but not vasorelaxation induced by agents that act solely on SMC. To explore the potential mechanisms responsible for this difference, porcine coronary artery SMC and EC preloaded with [3H]14,15-EET were treated with calcium ionophore A23187. Although the amount of EET incorporated into EC and SMC was similar, A23187 stimulated a five-fold increase in release of radioactivity from EC, but only a 21% increase in release from SMC. Thin layer chromatography (TLC) examination of cell lipids demonstrated that >70% of the incorporated radioactivity was present in phosphatidylcholine (PC) in both SMC and EC. After treatment of EC PC with PLA2, TLC analysis indicated that ≅75% of radioactivity was present as free EET, and 25% of radioactivity was present as lyso-PC. Therefore, most of the 14,15-EET was esterified into the sn-2 position of PC in EC. However, in SMC, ≅70% of radioactivity was present as lyso-PC after PLA2 treatment, indicating that the EET was predominately esterified into the sn-1 position. In contrast, all of the 14,15-EET was esterified into the sn-2 position of PI in both EC and SMC. These results suggest that the preferential incorporation of 14,15-EET into the sn-1 position of PC in SMC may help to explain the greater retention of the compound in SMC, while incorporation into the sn-2 position of PC in EC may facilitate agonist-induced 14,15-EET release and potentiation of EC-dependent porcine coronary artery relaxation.

AB - Epoxyeicosatrienoic acids (EETs) are readily incorporated into phospholipids of smooth muscle cells (SMC) and endothelial cells (EC). Incorporation of EETs into intact porcine coronary arteries potentiates EC-dependent relaxation, but not vasorelaxation induced by agents that act solely on SMC. To explore the potential mechanisms responsible for this difference, porcine coronary artery SMC and EC preloaded with [3H]14,15-EET were treated with calcium ionophore A23187. Although the amount of EET incorporated into EC and SMC was similar, A23187 stimulated a five-fold increase in release of radioactivity from EC, but only a 21% increase in release from SMC. Thin layer chromatography (TLC) examination of cell lipids demonstrated that >70% of the incorporated radioactivity was present in phosphatidylcholine (PC) in both SMC and EC. After treatment of EC PC with PLA2, TLC analysis indicated that ≅75% of radioactivity was present as free EET, and 25% of radioactivity was present as lyso-PC. Therefore, most of the 14,15-EET was esterified into the sn-2 position of PC in EC. However, in SMC, ≅70% of radioactivity was present as lyso-PC after PLA2 treatment, indicating that the EET was predominately esterified into the sn-1 position. In contrast, all of the 14,15-EET was esterified into the sn-2 position of PI in both EC and SMC. These results suggest that the preferential incorporation of 14,15-EET into the sn-1 position of PC in SMC may help to explain the greater retention of the compound in SMC, while incorporation into the sn-2 position of PC in EC may facilitate agonist-induced 14,15-EET release and potentiation of EC-dependent porcine coronary artery relaxation.

KW - Endothelium

KW - Epoxyeicosatrienoic acid

KW - Esterification

KW - Phospholipid

KW - Smooth muscle

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U2 - 10.1016/S0090-6980(03)00002-9

DO - 10.1016/S0090-6980(03)00002-9

M3 - Article

C2 - 12749592

AN - SCOPUS:0037387133

VL - 71

SP - 33

EP - 42

JO - Prostaglandins and Other Lipid Mediators

JF - Prostaglandins and Other Lipid Mediators

SN - 1098-8823

IS - 1-2

ER -