Gene modification is a potential therapy to heal an injured human heart. Injured human hearts can create scarring, which may lead to negative cardiac remodeling and heart failure. In contrast, zebrafish hearts can fully regenerate even after severe injury. Interestingly, zebrafish cardiac genes are highly conserved in humans, i.e., they have remained essentially unchanged throughout evolution. Thus, zebrafish is a genetically controllable model for studying heart regeneration. Despite intensive studies in zebrafish, a key regeneration process involved in proliferation of cardiomyocytes (heart muscle cells) remains unclear. The goal of this project is to develop novel devices and optical systems to reveal the bio-electro-mechanical mechanisms that trigger cardiomyocyte proliferation during cardiac regeneration. Using an advanced flexible wireless ECG (electrocardiogram) jacket developed for zebrafish, the investigators will continuously monitor electrical conduction changes and evaluate the mechanical function during regeneration of the heart after injury. Advanced imaging will reveal the detailed molecular events and make it possible to measure biological changes along with the electrical and mechanical activity recorded via the jacket. This multidisciplinary project will provide a unique educational training experience for a diverse group of UT-Arlington’s undergraduate and graduate students. Furthermore, the undergraduate students’ names will be included on resultant publications to promote their passion of research involvement and to assist the students in their future professional endeavors. Outreach will continue by sharing research findings with local high schools through seminars or by providing a summer research opportunity.
The goal of this project is to elucidate an unrevealed bio-electro-mechanical mechanism that induces cardiomyocyte proliferation during cardiac regeneration by using novel micro-devices and optical systems. Although there are many reports about the molecular event of Notch signaling in cardiomyocyte proliferation after injury, the electromechanical aspect of promoting cardiomyocyte proliferation remains unclear. Previous studies have shown that (a) Notch signaling is involved in cardiomyocyte proliferation after injury, and (b) Notch signaling is mechanosensitive and modulates cardiac electrical conduction. Studies are designed to test the hypothesis that there is a closed feedback loop among mechanosensitive Notch signaling, cardiac electrical conduction, and contraction that induces expression of certain Msx homeobox genes to promote cardiomyocyte proliferation during adult zebrafish cardiac regeneration. The Research Plan is organized under three tasks. The FIRST Task is to develop ECG acquisition and analysis from awake zebrafish during heart regeneration. The “fish ECG jacket†with a wireless microelectrode array (MEA) of 4 gold electrodes and electronics will be fabricated on parylene C membranes that enable continuous ECG acquisition while minimizing irritation and discomfort to the fish during regeneration. The ECG data of multiple fish will be sent to a cloud system with integrated machine learning algorithms for data processing and ECG pattern recognition. The SECOND Task is to develop high resolution multi-view fusion with axially swept light-sheet based ultra-microscopy (MV-ASLUM) to image ligand dependent-Notch and its downstream Msx expressions. MV-ASLUM will be integrated with a tissue clearing technique (CLARITY) to image in toto adult zebrafish hearts without physical sectioning. The THIRD Task is to modulate cardiac contractility and Notch signaling to regulate cardiomyocyte proliferation during regeneration via Msx expression. The Tg(hsp70:DN-MAML) zebrafish line and the CRISPR/CAS9 technique will be used to silence Notch and therefore inhibit Msx gene expression and cardiomyocyte proliferation and thereby verify the relationship between Notch inducing Msx gene expression and cardiac regeneration via cardiomyocyte proliferation. Contractility regulatory drugs (metoprolol, BDM, and isoproterenol) will be used to test the relationship of Notch inducible Msx gene expression during the regeneration process and nanoparticle (NP) targeted delivery will be used to overexpress Msx gene expression for regeneration after pharmacologically weakened cardiac contraction. This collaborative micro-device and biomedical imaging approach meets at the intersection of bio-electro-mechanics and cardiomyocyte proliferation during regeneration with a pathophysiological significance to molecular events and protection from myocardial infarction.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
