Divergent regulation of angiopoietin-1 and -2, Tie-2, and thrombospondin-1 expression by estrogen in the baboon endometrium

Authors

  • Thomas W. Bonagura,

    1. Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Studies in Reproduction, University of Maryland School of Medicine, Baltimore, Maryland
    Search for more papers by this author
  • Graham W. Aberdeen,

    1. Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Studies in Reproduction, University of Maryland School of Medicine, Baltimore, Maryland
    Search for more papers by this author
  • Jeffery S. Babischkin,

    1. Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Studies in Reproduction, University of Maryland School of Medicine, Baltimore, Maryland
    Search for more papers by this author
  • Robert D. Koos,

    1. Department of Physiology, Center for Studies in Reproduction, University of Maryland School of Medicine, Baltimore, Maryland
    Search for more papers by this author
  • Gerald J. Pepe,

    1. Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia
    Search for more papers by this author
  • Eugene D. Albrecht

    Corresponding author
    1. Department of Obstetrics, Gynecology and Reproductive Sciences, Center for Studies in Reproduction, University of Maryland School of Medicine, Baltimore, Maryland
    • Department of Obstetrics, Gynecology and Reproductive Sciences University of Maryland School of Medicine Bressler Research Laboratories 11-019 655 West Baltimore Street Baltimore, MD 21201.
    Search for more papers by this author

Abstract

Estrogen has an important role in the reconstruction of a new vascular network in the endometrium during each menstrual cycle; however, the underlying mechanisms are incompletely understood. Angiopoietin-1 (Ang-1) promotes vessel assembly, whereas Ang-2 and thrombospondin-1 (TSP-1) cause vessel breakdown. To determine the potential effect of estrogen on the expression of these angioregulatory factors in the endometrium, Ang-1, Ang-2, TSP-1, and Tie-2 receptor mRNA levels were assessed by real-time reverse transcriptase polymerase chain reaction in glandular epithelial and stromal cells isolated from the endometrium of ovariectomized baboons treated acutely with estradiol. Corresponding protein expression was assessed by immunocytochemistry and the proximity ligation assay (PLA) during advancing stages of the baboon menstrual cycle. Serum estradiol levels in ovariectomized baboons were 400 pg/ml within 4–6 hr of estradiol treatment. Ang-1 mRNA levels in glandular epithelial cells increased threefold (P < 0.01) within 4 hr of estradiol administration. In contrast, TSP-1 mRNA levels decreased four- to fivefold (P < 0.01) in endometrial glandular epithelial and stromal cells 4–6 hr after estradiol, whereas Ang-2 and Tie-2 expression was unaltered. Immunostaining for Ang-1 increased, TSP-1 decreased, and Ang-2 and Tie-2 were unaltered in the endometrium during the secretory compared with the proliferative phase of the cycle. Endometrial Ang-1 protein expression, quantified by PLA, increased 10-fold (P < 0.05) between the early proliferative and late proliferative/mid-secretory phases of the menstrual cycle in association with the rise in estrogen. In summary, estrogen induced a rapid, divergent, and cell-specific change in expression of angiostimulatory and angioinhibitory growth factors in the endometrium of the nonhuman primate. Mol. Reprod. Dev. 77: 430–438, 2010. © 2010 Wiley-Liss, Inc.

Ancillary