Pregnancy

Global Protein Expression Profiling Underlines Reciprocal Regulation of Caveolin 1 and Endothelial Nitric Oxide Synthase Expression in Ovariectomized Sheep Uterine Artery by Estrogen/Progesterone Replacement Therapy

Abstract
Ovariectomized (OVX) ewes were assigned to receive vehicle, progesterone (P4, 0.9g Controlled Internal Drug Release vaginal implants), estradiol-17beta; (E2, 5µg/kg bolus + 6µg/kg/day), or P4+E2 for 10 days (n = 3/group). Uterine artery endothelial proteins were mechanically isolated on day 10. The samples were used for protein expression profiling by the Ciphergen Proteinchip system and immunoblotting analysis of endothelial nitric oxide synthase (NOS3, also termed as eNOS) and caveolin 1. Uterine artery rings were cut and analyzed by immunohistochemistry to localize NOS3 and caveolin 1 expression. With the use of IMAC3 protein chip with loading as little as 2ug protein/sample, many protein peaks could be detected. Compared to vehicle controls, a ~133.1 kD protein was identified to be upregulated by 2-4 fold in OVX ewes receiving E2, P4, and their combination, whereas a ~22.6 kD protein was down- regulated by 2-4 fold in OVX ewes receiving E2 and E2/P4, but not in P4 treatments. Western blot analysis revealed that E2, P4, and their combination all increased NOS3 protein, whereas E2 and its combination with P4, but not P4 alone, down-regulated caveolin 1 expression. Immunohistochemical analysis revealed that NOS3 was mainly localized in the endothelium and upregulated by E2, whereas caveolin 1 was localized in both endothelium and smooth muscle and down-regulated by E2. Thus, our data demonstrate that uterine artery endothelial NOS3 and caveolin 1 are regulated reciprocally by estrogen replacement therapy. In keeping with the facts that E2, but not P4, causes uterine vasodilatation and that although E2 and P4 increase NOS3 expression, but only E2 decrease caveolin 1 expression, our current study suggest that both increased NOS3 expression and decreased caveolin 1 expression are needed to facilitate estrogen-induced uterine vasodilatation.

Key words: Estradiol • Gene regulation • Nitric oxide • Progesterone • Uterus

This article has been cited by other articles:

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