Wednesday, February 5, 2025
2/5/2025
The neural crest is a versatile cell population that holds great promise for the purposes of regenerative medicine due to its ability to form a multitude of diverse progeny ranging from the peripheral nervous system to the craniofacial skeleton and portions of the heart. The “cardiac neural crest” arises from the dorsal hindbrain and has the unique potential to form ectomesenchymal derivatives of the heart like the outflow tract septum and a subpopulation of ventricular cardiomyocytes Our preliminary data have uncovered a cardiac crest specific gene regulatory circuit that can reprogram other neural crest populations to cardiac crest fates and have revealed a requirement for cardiac crest-derived cells in adult heart regeneration in zebrafish. Here, we propose to elucidate the role of cardiac-specific subcircuit genes and their targets in acquisition of particular cell fates in the embryonic heart. To extend this to adult stages, we will examine gene regulatory changes that accompany loss of regenerative in mammals and examine the possible role of TGFβ and downstream genes in cardiac neural crest-derived cells therein. As the cardiac crest is a critically important embryonic cell population for normal formation and function of the heart, these studies hold the promise of uncovering novel potential target genes involved in cardiovascular birth defects and repair. Aim 1: Effects of “reprogramming” trunk neural crest identity to a cardiac crest fate. We will use single cell RNA-seq and single cell (sc) ATAC-seq to characterize transcriptional and epigenetic changes that occur in reprogrammed embryonic trunk crest cells over time and trace the fates of reprogrammed cells compared to endogenous cardiac neural crest cells. Aim 2: Role of Tgif1 and co-expressed putative downstream genes in outflow tract development. By coupling loss of function analysis with single cell RNA-seq, we will examine gene expression differences after depletion of Tgif1 as well as other co-expressed genes, including Twist1, FoxC2, and FoxP1. We will test their order of expression and whether they are downstream effectors of Tgif1 by testing the regulatory relationships between these genes. Finally, we will examine the long term effects of their loss of function on development of the cardiovascular system to identify key genes involved in cardiac neural crest fate acquisition. Aim 3: Exploring the role of cardiac neural crest-derived cells in mammalian heart regeneration. Newborn mice can regenerate their hearts after damage from post-natal (P) days 1 – 7. Our preliminary RNA- seq data suggest that there are profound gene regulatory changes that occur in cardiac neural crest derived cells between P1 and P7/8, including an upregulation of genes associated with the TGFβ pathway. Using scRNA-seq coupled with scATAC-seq, we will prepare a careful time course of changes in postnatal cardiac neural crest-derived heart cells under control and cryo-damage conditions and test whether genetic ablation of the neural crest blocks regenerative ability and if inhibition of the TGFβ pathway promotes heart regeneration.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).