Regulation of protease-activated receptor-1 by vasodilatory prostaglandins via NFAT

Cardiovasc Res. 2009 Sep 1;83(4):778-84. doi: 10.1093/cvr/cvp163. Epub 2009 May 21.


Aims: We recently reported that prostacyclin suppresses protease-activated receptor-1 (PAR-1) in human vascular smooth muscle cells (VSMC) via cyclic AMP and protein kinase A. This study examines the downstream mechanisms, particularly the role of nuclear factor of activated T-cells (NFAT).

Methods and results: Human saphenous vein VSMC were exposed to phorbol 12-myristate 13-acetate (PMA) to induce endogenous cyclooxygenase-2-dependent prostaglandin generation. This was found to attenuate PAR-1 expression; similar suppression was seen with the EP2-prostaglandin receptor agonist butaprost. Stimulation of the 'exchange protein directly activated by cyclic AMP' (EPAC) was without effect. The NFAT inhibitor cyclosporin A (CsA) or NFAT2 siRNA both reduced PAR-1 mRNA and protein expression and prevented the stimulatory effects of thrombin or PAR-1 activating peptide (TFLLRN) on ERK1/2 phosphorylation and interleukin-6 expression. CsA or mutation of the NFAT binding motif in the PAR-1 promoter also blunted PAR-1 promoter activity (luciferase reporter assay). These inhibitory actions of CsA were comparable to those of the prostacyclin-mimetic iloprost, and both CsA and iloprost similarly attenuated nuclear NFAT2 localization and binding to the PAR-1 promoter (chromatin immunoprecipitation assay).

Conclusions: This study provides the first evidence that NFAT2 contributes to the transcriptional control of PAR-1 in human VSMC and that PKA-dependent NFAT2 inhibition represents a mechanism by which vasodilatory prostaglandins regulate the vascular actions of thrombin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cells, Cultured
  • Cyclosporine / pharmacology
  • DNA / genetics
  • DNA / metabolism
  • Humans
  • Iloprost / pharmacology
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Models, Biological
  • Myocytes, Smooth Muscle / drug effects
  • Myocytes, Smooth Muscle / metabolism*
  • NFATC Transcription Factors / antagonists & inhibitors
  • NFATC Transcription Factors / genetics
  • NFATC Transcription Factors / metabolism*
  • Oligopeptides / pharmacology
  • Promoter Regions, Genetic
  • Prostaglandins / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / genetics
  • Receptor, PAR-1 / genetics
  • Receptor, PAR-1 / metabolism*
  • Tetradecanoylphorbol Acetate / pharmacology
  • Thrombin / pharmacology
  • Transcription, Genetic
  • Vasodilation / physiology*


  • IL6 protein, human
  • Interleukin-6
  • NFATC Transcription Factors
  • NFATC1 protein, human
  • Oligopeptides
  • Prostaglandins
  • RNA, Messenger
  • RNA, Small Interfering
  • Receptor, PAR-1
  • threonyl-phenylalanyl-leucyl-leucyl-arginyl-asparagine
  • Cyclosporine
  • DNA
  • Thrombin
  • Iloprost
  • Tetradecanoylphorbol Acetate