Lysophosphatidylcholine inhibits surface receptor-mediated intracellular signals in endothelial cells by a pathway involving protein kinase C activation

Kiyotaka Kugiyama, Masamichi Ohgushi, Seigo Sugiyama, Toyoaki Murohara, Kohji Fukunaga, Eishichi Miyamoto, Hirofumi Yasue

Research output: Contribution to journalArticlepeer-review

125 Citations (Scopus)

Abstract

Lysophosphatidylcholine (lysoPC) transferred from oxidatively modified low density lipoprotein (Ox-LDL) to the endothelial surface membrane has been shown to produce a selective unresponsiveness to cell surface receptor-regulated endothelium-dependent relaxation (EDR) in the rabbit aorta. To determine its mechanism we examined the effects of lysoPC on endothelial surface receptor-mediated transmembrane signals. Incubation for 1 minute with palmitoyl lysoPC (5-10 μM) decreased thrombin (Th, 2 units/ml)-or histamine (His, 0.1 mM)-stimulated inositol 1,4,5-trisphosphate (IP3) production in primary cultures of human umbilical vein endothelial cells (HUVECs). LysoPC also decreased Th- or His-induced intracellular calcium ([Ca2+]i, fura 2) elevation. Pretreatment with protein kinase C (PKC) inhibitors staurosporine (100 nM) or H-7 (50 μM) prevented the inhibitory actions of lysoPC, but HA-1004 had no effect. Incubation for 5 minutes with phorbol 12-myristate 13-acetate (PMA, 100 nM) produced the inhibitory actions on the Th- or His-induced intracellular signals, which closely mimic those exhibited by lysoPC. However, the inhibitory effect of lysoPC was lost in cells that were depleted of PKC by pretreatment for 24 hours with 100 nM PMA. Furthermore, incubation of the cells for 1 minute with lysoPC stimulated PKC activity in the membrane fraction. In organ chamber experiments with porcine coronary artery rings, pretreatment with staurosporine (20 nM) attenuated lysoPC-induced impairment of EDR in response to Th. These results indicate that lysoPC, which accumulates in Ox-LDL and atherosclerotic arterial walls, inhibits the early transmembrane signaling pathway in endothelial cells, and PKC activation could at least partially be involved in the negative regulation by lysoPC. These intracellular actions of lysoPC may play a role in the mechanism of the lysoPC-induced impairment of EDR in response to cell surface receptor-mediated stimulations.

Original languageEnglish
Pages (from-to)1422-1428
Number of pages7
JournalCirculation research
Volume71
Issue number6
DOIs
Publication statusPublished - 1992 Dec
Externally publishedYes

Keywords

  • Cytosolic free calcium
  • Endothelial cell
  • Inositol 1,4,5-trisphosphate
  • Lysophosphatidylcholine
  • Protein kinase C

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Fingerprint

Dive into the research topics of 'Lysophosphatidylcholine inhibits surface receptor-mediated intracellular signals in endothelial cells by a pathway involving protein kinase C activation'. Together they form a unique fingerprint.

Cite this