Treprostinil indirectly regulates endothelial colony forming cell angiogenic properties by increasing VEGF-A produced by mesenchymal stem cells

Thromb Haemost. 2015 Oct;114(4):735-47. doi: 10.1160/TH14-11-0907. Epub 2015 Jun 11.

Abstract

Pulmonary vasodilators and prostacyclin therapy in particular, have markedly improved the outcome of patients with pulmonary hypertension (PH). Endothelial dysfunction is a key feature of PH, and we previously reported that treprostinil therapy increases number and proliferative potential of endothelial colony forming cells (ECFC) isolated from PH patients' blood. In the present study, the objective was to determine how treprostinil contributes to the proangiogenic functions of ECFC. We examined the effect of treprostinil on ECFC obtained from cord blood in terms of colony numbers, proliferative and clonogenic properties in vitro, as well as in vivo vasculogenic properties. Surprisingly, treprostinil inhibited viability of cultured ECFC but did not modify their clonogenic properties or the endothelial differentiation potential from cord blood stem cells. Treprostinil treatment significantly increased the vessel-forming ability of ECFC combined with mesenchymal stem cells (MSC) in Matrigel implanted in nude mice. In vitro, ECFC proliferation was stimulated by conditioned media from treprostinil-pretreated MSC, and this effect was inhibited either by the use of VEGF-A blocking antibodies or siRNA VEGF-A in MSC. Silencing VEGF-A gene in MSC also blocked the pro-angiogenic effect of treprostinil in vivo. In conclusion, increased VEGF-A produced by MSC can account for the increased vessel formation observed during treprostinil treatment. The clinical relevance of these data was confirmed by the high level of VEGF-A detected in plasma from patients with paediatric PH who had been treated with treprostinil. Moreover, our results suggest that VEGF-A level in patients could be a surrogate biomarker of treprostinil efficacy.

Keywords: Stem cells; endothelial progenitor cells; prostacyclin analogues; vascular remodelling; vasculogenesis.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Angiogenesis Inducing Agents / pharmacology*
  • Animals
  • Antibodies / pharmacology
  • Antihypertensive Agents / pharmacology*
  • Biomarkers / blood
  • Cell Differentiation / drug effects
  • Cell Lineage
  • Cell Proliferation / drug effects*
  • Cell Survival / drug effects
  • Cells, Cultured
  • Child
  • Child, Preschool
  • Dose-Response Relationship, Drug
  • Endothelial Progenitor Cells / drug effects*
  • Endothelial Progenitor Cells / metabolism
  • Endothelial Progenitor Cells / transplantation
  • Epoprostenol / analogs & derivatives*
  • Epoprostenol / pharmacology
  • Female
  • Humans
  • Hypertension, Pulmonary / blood
  • Hypertension, Pulmonary / drug therapy
  • Hypertension, Pulmonary / physiopathology
  • Infant
  • Male
  • Mesenchymal Stem Cells / drug effects*
  • Mesenchymal Stem Cells / metabolism
  • Mice, Nude
  • Neovascularization, Physiologic / drug effects*
  • Paracrine Communication / drug effects*
  • RNA Interference
  • Signal Transduction / drug effects
  • Transfection
  • Up-Regulation
  • Vascular Endothelial Growth Factor A / antagonists & inhibitors
  • Vascular Endothelial Growth Factor A / blood
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism*
  • Young Adult

Substances

  • Angiogenesis Inducing Agents
  • Antibodies
  • Antihypertensive Agents
  • Biomarkers
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Epoprostenol
  • treprostinil