Prostaglandin E2 stimulates a Ca2+-dependent K+ channel in human erythrocytes and alters cell volume and filterability

Qing Li, Volker Jungmann, Anatoly Kiyatkin, Philip S. Low

Research output: Contribution to journalArticle

83 Scopus citations

Abstract

To understand the mechanism by which human red blood cells (RBCs) contribute to hemostasis and thrombosis, we have examined the effects of metabolites released by activated platelets on intact RBCs. Prostaglandin E2 (PGE2), a signal molecule produced by activated platelets, was observed to lower the filterability of human erythrocytes by ~30% at 10-10 M. PGE2 also caused a reduction in mean cell volume of ~10%. The shrinkage of red cells after PGE2 treatment was confirmed by documenting a decrease in osmotic fragility and an increase in cell density following exposure to the hormone. Careful analysis, however, revealed that only ~15% of the erythrocytes responded to stimulation with PGE2. Examination of the cause of cell shrinkage showed that induction of a PGE2-stimulated K+ efflux pathway leading to rapid loss of cellular K+ was responsible. The PGE2-stimulated K+ loss was also observed to be Ca2+-dependent, suggesting the possible involvement of the Gardos channel. Gardos channel participation was supported by the observation that two Gardos channel inhibitors, charybdotoxin and clotrimazole, independently blocked the PGE2-stimulated K+ efflux. Further evidence for Gardos channel activation came from experiments aimed at characterizing the efflux pathway followed by the obligatory counterion. Thus, K+ efflux was readily stimulated even when NO3/- was substituted for Cl-, suggesting that neither KCl cotransport nor Na/K/2Cl cotransport plays a prominent role in the PGE2-induced cell shrinkage. Further, the anion transporter band 3 was implicated as the counterion efflux route, since DIDS inhibited the PGE2-stimulated cell volume change without blocking the change in membrane potential. Taken together, we propose that release of PGE2 by activated platelets constitutes part of a mechanism by which activated platelets may recruit adjacent erythrocytes to assist in clot formation.

Original languageEnglish (US)
Pages (from-to)18651-18656
Number of pages6
JournalJournal of Biological Chemistry
Volume271
Issue number31
DOIs
StatePublished - 1996

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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