17β-estradiol-induced interaction of estrogen receptor α and human atrial essential myosin light chain modulates cardiac contractile function

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Item Type:	Article
Title:	17β-estradiol-induced interaction of estrogen receptor α and human atrial essential myosin light chain modulates cardiac contractile function
Creators Name:	Duft, K., Schanz, M., Pham, H., Abdelwahab, A., Schriever, C., Kararigas, G., Dworatzek, E., Davidson, M.M., Regitz-Zagrosek, V., Morano, I. and Mahmoodzadeh, S.
Abstract:	Chronic increased workload of the human heart causes ventricular hypertrophy, re-expression of the atrial essential myosin light chain (hALC-1), and improved contractile function. Although hALC-1 is an important positive inotropic regulator of the human heart, little is known about its regulation. Therefore, we investigated the role of the sex hormone 17beta-estradiol (E2) on hALC-1 gene expression, the underlying molecular mechanisms, and the impact of this regulatory process on cardiac contractile function. We showed that E2 attenuated hALC-1 expression in human atrial tissues of both sexes and in human ventricular AC16 cells. E2 induced the nuclear translocation of estrogen receptor alpha (ERalpha) and hALC-1 in AC16 cells, where they cooperatively regulate the transcriptional activity of hALC-1 gene promoter. E2-activated ERalpha required the estrogen response element (ERE) motif within the hALC-1 gene promoter to reduce its transcriptional activity (vehicle: 15.55 +/- 4.80 vs. E2: 6.51 +/- 3.69; ~2 fold). This inhibitory effect was potentiated in the presence of hALC-1 (vehicle: 11.13 +/- 3.66 vs. E2: 2.18 +/- 1.10; ~5 fold), and thus, hALC-1 acts as a co-repressor of ERalpha-mediated transcription. Yeast two-hybrid screening of a human heart cDNA library revealed that ERalpha interacts physically with hALC-1 in the presence of E2. This interaction was confirmed by Co-Immunoprecipitation and immunofluorescence in human atrium. As a further novel effect, we showed that chronic E2-treatment of adult mouse cardiomyocytes overexpressing hALC-1 resulted in reduced cell-shortening amplitude and twitching kinetics of these cells independent of Ca2+ activation levels. Together, our data showed that the expression of hALC-1 gene is, at least partly, regulated by E2/ERalpha, while hALC-1 acts as a co-repressor. The inotropic effect of hALC-1 overexpression in cardiomyocytes can be significantly repressed by E2.
Keywords:	Artrial Essential Myosin Light Chain, Estrogen Receptor {alpha}, 17{beta}-Estradiol, Transcriptional/Translational Regulation, Cardiac Contractile Function, Animals, Mice
Source:	Basic Research in Cardiology
ISSN:	0300-8428
Publisher:	Springer / Steinkopff
Volume:	112
Number:	1
Page Range:	1
Date:	January 2017
Official Publication:	https://doi.org/10.1007/s00395-016-0590-1
PubMed:	View item in PubMed

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