Angiotensin II type 2 receptor-stimulated activation of plasma prekallikrein and bradykinin release: role of SHP-1

Am J Physiol Heart Circ Physiol. 2012 Jun 15;302(12):H2553-9. doi: 10.1152/ajpheart.01157.2011. Epub 2012 Apr 20.

Abstract

ANG II type 2 receptors (AT(2)R) elicit cardioprotective effects in part by stimulating the release of kinins; however, the mechanism(s) responsible have not been fully explored. We demonstrated previously that overexpression of AT(2)R increased expression of prolylcarboxypeptidase (PRCP; a plasma prekallikrein activator) and release of bradykinin by mouse coronary artery endothelial cells (ECs). In the present study we hypothesized that the AT(2)R-stimulated increase in PRCP is mediated by the tyrosine phosphatase SHP-1, which in turn activates the PRCP-dependent prekallikrein-kallikrein pathway and releases bradykinin. We found that activation of AT(2)R using the specific agonist CGP42112A increased SHP-1 activity in ECs, which was blocked by the AT(2)R antagonist PD123319. Activation of AT(2)R also enhanced conversion of plasma prekallikrein to kallikrein, and this effect was blunted by a small interfering RNA (siRNA) to SHP-1 and abolished by the tyrosine phosphatase inhibitor sodium orthovanadate. Treating cells with a siRNA to PRCP also blunted AT(2)R-stimulated prekallikrein activation and bradykinin release. Furthermore, blocking plasma kallikrein with soybean trypsin inhibitor (SBTI) abolished AT(2)R-stimulated bradykinin release. These findings support our hypothesis that stimulation of AT(2)R activates a PRCP-dependent plasma prekallikrein pathway, releasing bradykinin. Activation of SHP-1 may also play an important role in AT(2)R-induced PRCP activation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bradykinin / metabolism*
  • Cells, Cultured
  • Coronary Vessels / cytology
  • Coronary Vessels / drug effects
  • Coronary Vessels / metabolism
  • Endothelial Cells / cytology
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism*
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / metabolism
  • Mice
  • Oligopeptides / pharmacology
  • Prekallikrein / metabolism*
  • Protein Tyrosine Phosphatase, Non-Receptor Type 6 / metabolism*
  • RNA, Small Interfering
  • Receptor, Angiotensin, Type 2 / metabolism*

Substances

  • Oligopeptides
  • RNA, Small Interfering
  • Receptor, Angiotensin, Type 2
  • CGP 42112A
  • Prekallikrein
  • Protein Tyrosine Phosphatase, Non-Receptor Type 6
  • Bradykinin