Defining the role of KLF15 in regulation of the Wnt Signaling in the healthy and diseased heart

• Applicant: Professorin Dr. Laura C. Zelarayan-Behrend
• Subject Area: Pharmacology ; Cardiology, Angiology
• Term: from 2010 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 158888035

• Final Report Year: 2018

Final Report Abstract

The postnatal heart is a dynamic organ capable of cellular and ventricular chamber remodeling in response to stress. Sustained stress, however, promotes transition from adaptive remodeling to heart failure. In depth understanding of mechanisms maintaining a homeostatic state will prevent this maladaptive response. Our study revealed age-specific, dynamic, transcriptional functions mediated by KLF15, crucial for cardiac homeostasis. We report that postnatally, KLF15 persistently activates cardiac metabolism, but represses in an agedependent manner, pathological, hypertrophic pathways associated with cardiomyocyte dedifferentiation and endothelial remodeling, including the Wnt pathway. Our integrative genomic and transcriptomic analyses identified novel target genes directly bound, and either activated or repressed by KLF15 in the adult heart in vivo. We found an association of KLF15 to the Wnt transcriptional factor TCF7L2 on chromatin regions regulating Wnt targets in the adult heart. Furthermore, we elucidated the chromatin-associated role of TCF7L2 and Wnt on cardiac disease gene regulation. These findings indicate the co-regulation of KLF15 and Wnt on cardiac remodeling genes. Notably, we discovered a cooperative program inducing aberrant endothelial remodeling, caused by a reduction of KLF15 and an activation of Wnt signaling in the adult heart. Within this specific program, we identified a so far uncharacterized cardiac gene - Shisa3, expressed in the developing heart and upregulated in cardiac hypertrophy, ischemia and failure. Importantly, we demonstrated that the KLF15 and Wntdependent, reciprocal SHISA regulation occurs also in the human myocardium. Altogether, our results unraveled and characterized a previously unknown, evolutionarily conserved, cardiac gene Shisa3, and attributed its significance in endothelial homeostasis of the adult heart, controlled by KLF15-Wnt dynamics. Finally, our findings defined a cardiac-specific nuclear KLF15-complex regulating Wnt transcriptional activity and provided novel information about an additional, evolutionarily conserved, tissue-specific component BZW2 and its association to cardiac biology. These data undoubtedly pave the way for the development of novel and efficient Wnt-targeting therapeutics for the prevention of progression from adaptive cardiac hypertrophy to heart failure. Outlook: our overall study contributed to the knowledge of fine tuning of the Wnt-off/–on states by a KLF15-mediated complex in mouse and human cardiac tissue and showed its contribution in transcriptional network regulation in tissue remodeling. The project laid the foundation for further projects at establishing proof-of-concept for specific KLF15/Wnt-target modulation as a therapeutic strategy in heart remodeling to prevent heart failure progression as well as at establishing the role of the newly identified targets in development and diseases. In this context, the cooperative role of KLF15 and Wnt-signaling in vessel formation in cardiac remodeling deserved also further investigation.

Publications

• (2012). Krueppel-like factor 15 regulates Wnt/Beta-catenin transcription and controls cardiac progenitor cell fate in the postnatal heart. EMBO Mol Med 4: 992-1007
  Noack C, Zafiriou MP, Schaeffer HJ, Renger A, Pavlova E, Dietz R, Zimmermann WH, Bergmann MW, Zelarayan LC
  
• (2013). The Four and a Half LIM-domain (FHL) 2 Controls Early Cardiac Cell Commitment and Expansion via Regulating Betacatenin-Dependent Transcription. Stem Cells 31:928-40
  Renger A, Zafiriou MP, Noack C, Pavlova E, Becker A, Sharkova K, Bergmann MW, El- Armouche A, Zimmermann WH, Zelarayan LC
  
• (2014) Genetic Background Defines the Regulation of Postnatal Cardiac Growth by 17beta-Estradiol Through a beta-Catenin Mechanism. Endocrinology 155:2667-2676
  Kararigas, G., B.T. Nguyen, L.C. Zelarayan, M. Hassenpflug, K. Toischer, H. Sanchez- Ruderisch, G. Hasenfuss, M.W. Bergmann, H. Jarry, and V. Regitz-Zagrosek
  
• (2016), Myocardial Pharmacoregeneration. Springer International Publishing Switzerland. G. Steinhoff (ed.), Regenerative Medicine - from Protocol to Patient, 3rd Edition
  Laura C. Zelarayán , Maria Patapia Zafiriou, and Wolfram-Hubertus Zimmermann
  
• (2017). Generation of a KLF15 homozygous knockout human embryonic stem cell line using paired CRISPR/Cas9n, and human cardiomyocytes derivation. Stem Cell Res. 23:127-131
  Noack C, Haupt LP, Zimmermann WH, Streckfuss-Bömeke K, Zelarayán LC
  
• (2018). A context-specific cardiac Beta-catenin and GATA4 interaction influences TCF7L2 occupancy and remodels chromatin driving disease progression in the adult heart. Nucleic Acids Research
  Lavanya M. Iyer, Sankari Nagarajan, Monique Woelfer, Eric Schoger, Sara Khadjeh, Maria Patapia Zafiriou, Vijayalakshmi Kari, Jonas Herting, Sze Ting Pang, Tobias Weber, Franziska S. Rathjens, Thomas H. Fischer, Karl Toischer, Gerd Hasenfuss, Claudia Noack, Steven A. Johnsen and Laura C. Zelarayán
  
• (2018). The Mingle-Mangle of Wnt Signaling and Extracellular Vesicles: Functional Implications for Heart Research
  Julia Christina Gross and Laura Cecilia Zelarayán