Protein kinase C-delta mediates von Willebrand factor secretion from endothelial cells in response to vascular endothelial growth factor (VEGF) but not histamine

J Thromb Haemost. 2008 Nov;6(11):1962-9. doi: 10.1111/j.1538-7836.2008.03138.x.

Abstract

Background: Vascular endothelial growth factor (VEGF) and histamine induce von Willebrand factor (VWF) release from vascular endothelial cells. Protein kinase C (PKC) is involved in the control of exocytosis in many secretory cell types.

Objectives: We investigated the role of PKC and the interactions between PKC and Ca2+ signaling in both VEGF-induced and histamine-induced VWF secretion from human umbilical vein endothelial cells (HUVECs).

Results: Several PKC inhibitors (staurosporine, Ro31-8220, myristoylated PKC peptide inhibitor and Go6983) block VEGF-induced but not histamine-induced VWF secretion. PKC-alpha and novel PKCs (PKC-delta, PKC-epsilon, and PKC-eta), but not PKC-beta, are expressed in HUVECs. Both VEGF and histamine activate PKC-delta. However, gene inactivation experiments using small interfering RNA indicate that PKC-delta (but not PKC-alpha) is involved in the regulation of VEGF-induced but not histamine-induced secretion. Both VEGF and histamine induce a rise in cytosolic free Ca2+ ([Ca2+]c), but the response to VEGF is weaker and even absent in a significant subset of cells. Furthermore, VEGF-induced secretion is largely preserved when the rise in [Ca2+]c is prevented by BAPTA-AM.

Conclusions: Our study identifies striking agonist specificities in signal-secretion coupling. Histamine-induced secretion is dependent on [Ca2+]c but not PKC, whereas VEGF-induced secretion is largely dependent on PKC-delta and significantly less on [Ca2+]c. Our data firmly establish the key role of PKC-delta in VEGF-induced VWF release, but suggest that a third, VEGF-specific, signaling intermediate is required as a PKC-delta coactivator.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium Signaling
  • Cells, Cultured
  • Endothelial Cells / metabolism*
  • Endothelium, Vascular / cytology
  • Histamine / pharmacology*
  • Humans
  • Protein Kinase C-delta / metabolism*
  • Vascular Endothelial Growth Factor A / pharmacology
  • Vascular Endothelial Growth Factor A / physiology*
  • von Willebrand Factor / metabolism*

Substances

  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • von Willebrand Factor
  • Histamine
  • Protein Kinase C-delta