Abstract 18962: The Epithelial-Mesenchymal Master Regulator Zeb1 Orchestrates the Cardiac Determinant Transcription Factor Castor Zinc Finger Protein 1 (casz1) Expression and Function in Heart Regeneration
Introduction and Hypothesis: Casz1 has been recently described as an important player during heart development in both mouse and Xenopus. In mice, Casz1 deletion is embryonic lethal at stage E17.5 determining heart hypoplasia, ventricular septal defects and a generally aberrant heart morphology. Here, to gather mechanistic insights about Casz1 action, we took advantage of different systems including mouse embryonic stem cells (mES), adult infarcted mouse hearts and human primary cardiac mesenchymal cells (CMSC).
Methods and Results: An integrated ChIP-sequencing/transcriptomic approach performed in undifferentiated and stemness-released mES detected the transcriptional repressor Zeb1 directly bound to the promoter/enhancer region of Casz1. Following release from stemness, Zeb1 rapidly detached allowing Casz1 transcripts to be detected. Similarly, in a mouse model of MI, a rapid (3 hours) decrease of Zeb1 mRNA occurred at both the border and infarct zone. This phenomenon was paralleled by a strong induction of Casz1 mRNA in the infarct zone (3 days). In this context, cells positive for Casz1 were also positive for vimentin, a typical cardiac mesenchymal marker. This evidence prompted us to investigate the role of Casz1 during cellular reprogramming of CMSC to cardiovascular precursors taking advantage of the newly synthesized hybrid small molecule Hyb574 featuring a furossanic NO-donor coupled to a class I-specific HDAC inhibitor (MS275). This drug induced mitochondrial biogenesis by PGC1-alpha activation, growth arrest, and induced expression of cardiomyocyte specific transcripts such as those encoding for contractile proteins including alpha sarcomeric actin (Acta1), troponin T1 (TNNT1) and the carnitine-magnesium-complex (CMK). Remarkably, ChIP/qRT-PCR experiments showed binding of Casz1 to Acta1, TNNT1 and CMK promoters while Casz1-specific siRNA knock-down experiments abrogated any cardiogenic response in CMSC.
Conclusions: Our work demonstrates that Casz1 is important for mES cardiovascular differentiation. The transcription factor, however, is rapidly re-expressed after MI and may contribute CMSC reprogramming into cardiac precursors.
Author Disclosures: C. Cencioni: None. F. Spallotta: None. M. Savoia: None. J. Heid: None. F. Limana: None. Y. D’Alessandra: None. L. Lazzarato: None. C. Döring: None. M.L. Hansmann: None. R. Fruttero: None. A. Gasco: None. Z. Liu: None. C.J. Thiele: None. A.M. Zeiher: None. C. Gaetano: None.
- © 2016 by American Heart Association, Inc.