Abstract 15790: Hippo Pathway Effector TEAD1 Promotes Direct Cardiac Reprogramming

• Published in: Circulation (New York, N.Y.) N.Y.), 2019-11, Vol.140 (Suppl_1 Suppl 1), p.A15790-A15790
• Main Authors: Singh, Vivek P, Pinnamaneni, Jaya Pratap, Pugazenthi, Aarthi, Sanagasetti, Deepthi, Almousa, Ayman, Mathison, Megumi, Wang, Kai, Elsenousi, Abdussalam, Shafii, Alexis E, Yang, Jianchang, Martin, James F, Rosengart, Todd K
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.140.suppl_1.15790

IntroductionReprogramming of cardiac fibroblasts into induced cardiomyocyte-like cells (iCMs) in situ represents a promising strategy for cardiac regeneration.HypothesisModification of reprogramming factors, alteration of the stoichiometry of Gata4, Mef2c, Tbx5 (GMT),manipulating signaling pathways, or the use of defined culture conditions, promoted and improved the quality of cardiac reprogramming in mouse, and human fibroblasts, in vitro. However,using all the above modifications, the reprogramming efficiency and induction of functional cardiomyocytes is still remains very low, specially in human cells, where it requires the addition of extra factors-an important challenge to this field.MethodsTo identify additional regulator which can enhance rat and human cardiac reprogramming with a minimum cocktail, we used TEAD-1 mediated override of the anti-proliferative hippo pathway. Rat and human lentiviruses expressing Gata4, Mef2c, Tbx5 or Tead1 were transduced for 48 hours into cultures of rat and human fibroblasts. iCMs generation was quantified 2 weeks’ post-transduction by FACS, qRT PCR and immunofluorescence (IF) for the expression of endogenous cardiac troponin T (cTnT) and α-sarcomeric actinin.ResultsHere we show that administration of the Hippo pathway effector TEAD1(Td), in combinations with Gata4 and Mef2c (GMTd), more efficiently induced cTnT expression in both human and rat cardiac fibroblasts than did GMT and enhanced contractile iCM generation in rat cells as early as 4 weeks. We also observed advanced sarcomere organization in iCMs after only 4 weeks of reprogramming with GMTd as compared to GMT alone. QRT-PCR analysis shows that GMTd (but not GMT) significantly upregulated the cardiac genes Connexin-43 and Myocardin as well as ZEB1. Next we investigate the mechanism underlying TEAD-mediated effects and found TEAD1 to upregulate expression of the epigenetic gene activator p300.ConclusionsTEAD1 is capable to reprogram rat and human cardiac fibroblasts towards cardiac fate by increasing the efficiency, maturation and speed of direct reprogramming.These findings provide the first demonstration of a hippo pathway effector in cardiac reprogramming and pave the path for the effective treatment for heart failure.