Scientists at the Stanford University School of Medicine have identified the sets of biological and chemical signals necessary to quickly and efficiently direct human embryonic stem cells.
If successful, researchers could grow pure populations of any of 12 cell types, including bone, heart muscle and cartilage within days rather than the weeks or months previously required.
This is key toward clinically useful regenerative medicine – potentially allowing researchers to generate new beating heart cells to repair damage after a heart attack or to create cartilage or bone to reinvigorate creaky joints or heal from trauma.
The study was published in the journal Cell. Scientists also highlighted that human development appears to rely on processes that are evolutionary, as shown on the patterns of gene expression during human embryo segmentation. These insights may also lead to a better understanding of how congenital defects occur.
Researchers found that the quickest, most efficient way to micromanage the cells’ developmental decisions was to apply a simultaneous combination of factors that both encouraged the differentiation into one lineage while also actively blocking the cells from a different fate – a kind of “yes” and “no” strategy. “We learned during this process that it is equally important to understand how unwanted cell types develop and find a way to block that process while encouraging the developmental path we do want,” said researcher Kyle Loh.
By carefully guiding the cells’ choices at each fork in the road, scientists were able to generate bone cell precursors that formed human bone when transplanted into laboratory mice and beating heart muscle cells, as well as 10 other mesodermal-derived cell lineages.
The process mirrors what is known to occur in other animals, and confirms that the segmentation process in human development has been conserved through evolution.