Differential effect of estrogen receptor alpha and beta agonists on the receptor for advanced glycation end product expression in human microvascular endothelial cells

Estrogens are known to induce the expression of the receptor for advanced glycation end products (RAGE). In the current investigation, we examined the effect of three estrogens with different potency for specific estrogen receptors (ER) on RAGE expression in human microvascular endothelial cells (HMEC-1). Of the three estrogens tested, ethinyl estradiol (EE), an estrogen receptor alpha (ERα) agonist, was the strongest inducer of RAGE expression in HMEC-1. By comparison, 17-epiestriol, an estrogen receptor beta (ERβ) agonist and 17-β-E2, an ER agonist that is almost equally potent for ERα and ERβ were less effective in stimulating RAGE expression. We then determined whether the prooxidative and proinflammatory transcription factors Sp1 or NF-κB were downstream modulators of ER-agonists that mediate RAGE expression. The results implicated Sp1 but not NF-κB in estrogen-dependent RAGE expression. We further demonstrated that ERα but not ERβ was responsible for the estrogen-mediated Sp1 activation. In summary, the present investigation demonstrates that a direct interaction of EE-ERα-Sp1 plays a central role in estrogen-induced RAGE expression in HMEC-1.