Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Str. 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Str. 26, 50924 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany.