Expression and subcellular distribution of native estrogen receptor b in murine C2C12 cells and skeletal muscle tissue

MILANESI LORENA,; VASCONSUELO, ANDREA ANAHÍ; BOLAND ANA,; BOLAND, RICARDO

STEROIDS

ELSEVIER SCIENCE INC

Año: 2009 p. 489 - 497

0039-128X

We have recently described the expression and intracellular localization of ER in murine C2C12 cellsand skeletal muscle tissue. In separate studies, a protective role of 17-estradiol against apoptosis exertedmainly at the mitochondrial level was also shown in the C2C12 muscle cell line. However, this functionalevidencewas in accordance with the participation of ER .We have then here investigated the expressionand subcellular distribution of native ERin similar skeletal muscle cultured cells and tissue developed invivo. ERwas detected by immunoblotting using specific antibodies and ligand blot analysis after subcellularfractionation. Immunolocalization was confirmed using conventional and confocal microscopy. ER was found to a great extent in mitochondria and in lower amounts in the cytosolic fraction, differentlyto ER which localizes in microsomes, cytosol, mitochondria, and also in the nucleus of muscle tissue.ER expression was also demonstrated by RT-PCR. Finally, the mitochondrial localization of native ER in C2C12 muscle cells was corroborated after transient transfection with specific ER siRNAs. These dataraise the possibility that the antiapoptotic action of 17-estradiol in muscle cells may be related in partto a direct action of the hormone on mitochondria through ER .