Using single-cell RNA sequencing techniques, researchers divided up the cells from each sample into three known categories:
- Myocardial cells (heart muscle cells)
- Endothelial cells (make blood vessels)
- Fibroblasts (“hold everything together”)
“The study provides both a temporal and spatial atlas that plots the development of the different cell populations in each of the four chambers,” Seidman explained. “The converse is also true: by looking at a cell’s RNA expression, we can gather clues to its origins.”
The results showed errors in specific cell types in mice with a genetic mutation also associated with congenital heart defects in humans, as well as a plethora of information concerning the location of certain cell types in the heart at different times during development. However, they also made an unexpected discovery: a seemingly new cell type that express genes from both myocardial cells and fibroblasts. Researchers are still unsure what these cells are and what role they play in embryonic development.
Mouse hearts are similar to human hearts and make a good model for study, but several differences limit the information scientists can glean from mouse studies. Mouse hearts are three thousand times smaller and beat ten times as fast as human hearts. But shared similarities between the two structures like four heart chambers, electrical signaling, and molecules involved in muscle function make the mouse heart just good enough to take away significant conclusions.
Seidman and the team from Harvard plan on continuing research with mice heart structure and function, looking for concrete explanations for why certain congenital heart defects develop. The present study was recently published in the journal Development Cell.
Source: Harvard Medical School