Signal transducer and activator of transcription 3-stimulated hypoxia inducible factor-1alpha mediates estrogen receptor-alpha-induced mesenchymal stem cell vascular endothelial growth factor production.

OBJECTIVE

Vascular endothelial growth factor, a critical factor in angiogenesis, mediates stem cell paracrine protective effects on ischemic myocardium. Studies on the role of sex in stem cell function have demonstrated that female mesenchymal stem cells produce greater vascular endothelial growth factor and provide better cardiac protection compared with male mesenchymal stem cells. The purpose of this study was to determine the mechanisms by which estrogen affects mesenchymal stem cell function as a potential therapeutic measure during ex vivo expansion, before therapeutic use.

METHODS

A single-step purification method using adhesion to cell culture plastic was adopted to isolate mesenchymal stem cells from wild-type, estrogen receptor-alpha knockout, estrogen receptor-beta knockout, and signal transducer and activator of transcription 3 knockout mice. Mesenchymal stem cells were treated with or without 17beta-estradiol, estrogen receptor-alpha agonist (propyl pyrazoletriol), and estrogen receptor-beta agonist (diarylpropionitrile).

RESULTS

17beta-estradiol significantly increased mesenchymal stem cell vascular endothelial growth factor production in a dose-dependent manner. Both estrogen receptor-alpha and estrogen receptor-beta were expressed in mesenchymal stem cells. Administration of 17beta-estradiol or estrogen receptor-alpha agonist (not estrogen receptor-beta agonist) elevated mesenchymal stem cell vascular endothelial growth factor, hypoxia inducible factor-1alpha expression, and signal transducer and activator of transcription 3 activation. However, these effects were neutralized in estrogen receptor-alpha knockout mesenchymal stem cells, not estrogen receptor-beta knockout. Signal transducer and activator of transcription 3 knockout abolished estrogen receptor-alpha-induced hypoxia inducible factor-1alpha and subsequent vascular endothelial growth factor production.

CONCLUSION

17beta-estradiol-induced vascular endothelial growth factor production from mesenchymal stem cells appears to be mediated through estrogen receptor-alpha-activated signal transducer and activator of transcription 3-mediated hypoxia inducible factor-1alpha expression.