Sabrina Schroeder, Andreas Zimmermann, Didac Carmona-Gutierrez, Tobias Eisenberg, Christoph Ruckenstuhl, Aleksandra Andryushkova, Tobias Pendl, Alexandra Harger and Frank Madeo* 1 Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria. 2 Division of Endocrinology and Metabolism, Dept. of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria. # These authors contributed equally to this work. * Corresponding Author: F. Madeo, Humboldtstrasse 50; 8010 Graz, Austria; Tel: +43 316 380 8878; Fax: +43 316 380 9898; E-mail: frank.madeo@uni-graz.at