27-Hydroxycholesterol is an endogenous SERM that inhibits the cardiovascular effects of estrogen

M Umetani, H Domoto, AK Gormley, IS Yuhanna… - Nature medicine, 2007 - nature.com
M Umetani, H Domoto, AK Gormley, IS Yuhanna, CL Cummins, NB Javitt, KS Korach…
Nature medicine, 2007nature.com
The cardioprotective effects of estrogen are mediated by receptors expressed in vascular
cells. Here we show that 27-hydroxycholesterol (27HC), an abundant cholesterol metabolite
that is elevated with hypercholesterolemia and found in atherosclerotic lesions, is a
competitive antagonist of estrogen receptor action in the vasculature. 27HC inhibited both
the transcription-mediated and the non-transcription-mediated estrogen-dependent
production of nitric oxide by vascular cells, resulting in reduced estrogen-induced …
Abstract
The cardioprotective effects of estrogen are mediated by receptors expressed in vascular cells. Here we show that 27-hydroxycholesterol (27HC), an abundant cholesterol metabolite that is elevated with hypercholesterolemia and found in atherosclerotic lesions, is a competitive antagonist of estrogen receptor action in the vasculature. 27HC inhibited both the transcription-mediated and the non-transcription-mediated estrogen-dependent production of nitric oxide by vascular cells, resulting in reduced estrogen-induced vasorelaxation of rat aorta. Furthermore, increasing 27HC levels in mice by diet-induced hypercholesterolemia, pharmacologic administration or genetic manipulation (by knocking out the gene encoding the catabolic enzyme CYP7B1) decreased estrogen-dependent expression of vascular nitric oxide synthase and repressed carotid artery reendothelialization. As well as antiestrogenic effects, there were proestrogenic actions of 27HC that were cell-type specific, indicating that 27HC functions as an endogenous selective estrogen receptor modulator (SERM). Taken together, these studies point to 27HC as a contributing factor in the loss of estrogen protection from vascular disease.
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