Project description:The purpose of this study was to identify the source of Wnt signals that lead to development/proliferation of the heart fields, particularly the second heart field. To this end, we knocked out Wntless (Wls), which is necessary for Wnt secretion, in Mesp1+ lineage cells. We performed single cell RNA-seq to better identify the source of Wnt signals and the effects of the loss of Wnt secretion in mesoderm.
Project description:Analysis of whole heart samples from Hdac3-Isl1KO embryos at embryonic day E9.5. Results provide insights into the role of Hdac3 in second heart field-derived cardiac cells. We used microarray to investigate the gene expression program affected by Hdac3 during cardiac development and identified patterns of differentially-expressed genes and pathways during this process.
Project description:Cells from second heart field of mice with mixed B6/129/SvEv background were isolated and single cell sequencing was performed for two stages: E9.5 and E10.5. After dissection, hearts were minced and subjected to cell dissociation using trypsin.
Project description:Heart morphogenesis is highly complex, and depends on the generation of diverse cell types which interact with each other in an orchestrated manner to remodel the primitive heart tube into a functional organ. Cardiac outflow tract formation critically depends on continued contribution of cardiac progenitor cells from the anterior second heart field to ensure proper growth of the outflow tract. Prior to entering the outflow tract, neural crest cells migrate in close apposition to the second heart field and may play important roles in regulating second heart field growth dynamics, however the molecular mechanisms by which neural crest cells interact with the second heart field have remained elusive. Here, we discover that neural crest cells are a primary source of Dickkopf1 (DKK1), a secreted Wnt signalling inhibitor, which modulates Wnt signalling activity in the second heart field to impose a balance between progenitor maintenance and differentiation. Further, we identify the ubiquitin ligase NEDD4 as a critical regulator of DKK1 levels, with disruption of Nedd4 activity leading to outflow tract defects. In the context of disease pathogenicity, we show a novel human congenital heart disease variant of NEDD4 has lost the ability to ubiquitinate DKK1, and is associated with heart defects in a mouse model of the genetic variant. Our findings point to an unexpected role for neural crest cells acting as a rheostat of Wnt signalling activity in cardiac progenitors, identifying a new molecular pathway underpinning correct outflow tract morphogenesis, and a new causative factor of congenital heart disease.
