Stem cell biologists have tried unsuccessfully for years to produce cells that will give rise to functional arteries and give physicians new options to combat cardiovascular disease, the world’s leading cause of death.

But new techniques developed at the Morgridge Institute for Research and the University of Wisconsin–Madison have produced, for the first time, functional arterial cells at both the quality and scale to be relevant for disease modeling and clinical application.

Reporting in the July 10 issue of the journal Proceedings of the National Academy of Sciences, scientists in the lab of stem cell pioneer James Thomson describe methods for generating and characterizing arterial endothelial cells – the cells that initiate artery development – that exhibit many of the specific functions required by the body. Further, these cells contributed both to new artery formation and improved survival rate of mice used in a model for myocardial infarction. Mice treated with this cell line had an 83 percent survival rate, compared to 33 percent for controls.

“The cardiovascular diseases that kill people mostly affect the arteries, and no one has been able to make those kinds of cells efficiently before,” says Jue Zhang, a Morgridge assistant scientist and lead author. “The key finding here is a way to make arterial endothelial cells more functional and clinically useful.”

The research team applied two pioneering technologies to the project. First, they used single–cell RNA sequencing to identify the signaling pathways critical for arterial endothelial cell differentiation. They found about 40 genes of optimal relevance. Second, they used CRISPR–Cas9 gene editing technology that allowed them to create reporter cell lines to monitor arterial differentiation in real time. “With this technology, you can test the function of these candidate genes and measure what percentage of cells are generating into our target arterial cells,” says Zhang.

The research group developed a protocol around five key growth factors that make the strongest contributions to arterial cell development. They also identified some very common growth factors used in stem cell science, such as insulin, that surprisingly inhibit arterial endothelial cell differentiation.