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Updated: Sep 21, 2025
Improved Generation of Induced Cardiomyocytes Using a Polycistronic Construct Expressing Optimal Ratio of Gata4, Mef2c and Tbx5
Published on: November 13, 2015
Activation of Nkx2.5 transcriptional program is required for adult myocardial repair
Carmen de Sena-Tomás1, Angelika G Aleman2, Caitlin Ford3
1Division of Cardiology, Department of Pediatrics, College of Physicians & Surgeons, Columbia University, New York, NY, 10032, USA.
Abstract:
The cardiac developmental network has been associated with myocardial regenerative potential. However, the embryonic signals triggered following injury have yet to be fully elucidated. Nkx2.5 is a key causative transcription factor associated with human congenital heart disease and one of the earliest markers of cardiac progenitors, thus it serves as a promising candidate. Here, we show that cardiac-specific RNA-sequencing studies reveal a disrupted embryonic transcriptional profile in the adult Nkx2.5 loss-of-function myocardium. nkx2.5-/- fish exhibit an impaired ability to recover following ventricular apex amputation with diminished dedifferentiation and proliferation. Complex network analyses illuminate that Nkx2.5 is required to provoke proteolytic pathways necessary for sarcomere disassembly and to mount a proliferative response for cardiomyocyte renewal. Moreover, Nkx2.5 targets embedded in these distinct gene regulatory modules coordinate appropriate, multi-faceted injury responses. Altogether, our findings support a previously unrecognized, Nkx2.5-dependent regenerative circuit that invokes myocardial cell cycle re-entry, proteolysis, and mitochondrial metabolism to ensure effective regeneration in the teleost heart.
Insights
Transcription factor Nkx2.5 is crucial for heart regeneration. Loss of Nkx2.5 impairs zebrafish heart repair by disrupting embryonic gene expression, proteolysis, and cell proliferation pathways.
Area of Science:
- Cardiovascular Biology
- Developmental Biology
- Regenerative Medicine
Background:
- The cardiac developmental network influences myocardial regenerative potential.
- Embryonic signals activating post-injury cardiac repair remain incompletely understood.
- Nkx2.5, a transcription factor linked to congenital heart disease and cardiac progenitor development, is a key candidate for investigating regenerative mechanisms.
Purpose of the Study:
- To investigate the role of the transcription factor Nkx2.5 in cardiac regeneration following injury.
- To elucidate the embryonic signals and gene regulatory networks governed by Nkx2.5 that are essential for myocardial repair.
Main Methods:
- Cardiac-specific RNA-sequencing was performed on adult Nkx2.5 loss-of-function (nkx2.5-/-) zebrafish.
- Ventricular apex amputation model was used to assess regenerative capacity.
- Complex network analyses were employed to identify Nkx2.5-dependent pathways.
Main Results:
- Nkx2.5 loss-of-function disrupted the embryonic transcriptional profile in adult myocardium.
- nkx2.5-/- zebrafish showed impaired recovery after ventricular amputation, with reduced dedifferentiation and proliferation.
- Nkx2.5 was found to be essential for activating proteolytic pathways for sarcomere disassembly and promoting cardiomyocyte proliferation.
Conclusions:
- Nkx2.5 plays a critical role in orchestrating cardiac regeneration.
- A previously unrecognized Nkx2.5-dependent regenerative circuit involves cell cycle re-entry, proteolysis, and mitochondrial metabolism.
- These findings highlight Nkx2.5 as a key regulator for effective myocardial repair in teleost hearts.
