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Selective Activation of Estrogen Receptor α Activation Function-1 Is Sufficient to Prevent Obesity, Steatosis, and Insulin Resistance in Mouse.

Guillaume, Maeva; Handgraaf, Sandra; Fabre, Aurélie; Raymond-Letron, Isabelle; Riant, Elodie; Montagner, Alexandra; Vinel, Alexia; Buscato, Melissa; Smirnova, Natalia; Fontaine, Coralie; Guillou, Hervé; Arnal, Jean-François; Gourdy, Pierre.
Am J Pathol; 187(6): 1273-1287, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28502695
Estrogen receptor α (ERα) regulates gene transcription through two activation functions (ERα-AF1 and ERα-AF2). We recently found that the protection conferred by 17ß-estradiol against obesity and insulin resistance requires ERα-AF2 but not ERα-AF1. However, the interplay between the two ERα-AFs is poorly understood in vivo and the metabolic influence of a specific ERα-AF1 action remains to be explored. To this end, wild-type, ERα-deficient, or ERα-AF1-deficient ovariectomized female mice were fed a high-fat diet and concomitantly administered with vehicle or tamoxifen, a selective ER modulator that acts as a ERα-AF1 agonist/ERα-AF2 antagonist. In ovariectomized wild-type mice, tamoxifen significantly reduced food intake and totally prevented adiposity, insulin resistance, and steatosis. These effects were abolished in ERα-deficient and ERα-AF1-deficient mice, revealing the specific role of ERα-AF1 activation. Finally, hepatic gene expression changes elicited by tamoxifen in wild-type mice were abrogated in ERα-AF1-deficient mice. The combination of pharmacologic and transgenic approaches thus indicates that selective ERα-AF1 activation by tamoxifen is sufficient to elicit metabolic protection, contrasting with the specific requirement of ERα-AF2 in the metabolic actions of 17ß-estradiol. This redundancy in the ability of the two ERα-AFs to separately mediate metabolic prevention strikingly contrasts with the contribution of both ERα-AFs in breast cancer proliferation, shedding new light on the therapeutic potential of selective ER modulation.
Selo DaSilva