Researchers have developed a protocol for generating almost pure populations of cardiomyocytes from human pluripotent stem cells (hPSCs) simply by modulating canonical Wnt signaling at defined time points in the differentiation process, using readily accessible small molecule compounds. Sean P. Palecek, Ph.D., and colleagues at the University of Wisconsin claim their approach appears far more efficient, reproducible, and inexpensive than existing techniques that require enrichment steps and the use of serum and growth factors.
Prior work by the Wisconsin team and others have suggested that combining growth factors and/or serum with early induction of canonical Wnt signaling and suppression of canonical Wnt signaling at later stages of hPSC differentiation could boost the yield of differentiated cardiomyocytes. Building on this, the Wisconsin developed an approach that did away with the need for serum and growth factors. Instead, they found it was possible to direct hPSC differentiation into cardiomyocytes simply by treating the cells with glycogen synthase kinase 3 inhibitors at a defined time point early in the differentiation process and then chemically inhibiting Wnt signaling later on.
The researchers validated their technology by generating functional, contractile cardiomyocytes from multiple hPSC lines including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hIPSCs). In fact, using this differentiation protocol resulted in cell populations that contained up to 98% cardiomyocytes and yielded up to 15 cardiomyocytes per hPSC. The team reports its approach in PNAS in a paper titled “Robust cardiomyocyte differentiation from human pluripotent stem cells via temporal modulation of canonical Wnt signaling.”
“Our protocol is more efficient and robust,” Dr. Palecek explains “We have been able to reliably generate greater than 80% cardiomyocytes in the final population while other methods produce about 30% cardiomyocytes with high batch-to-batch variability. The biggest advantage of our method is that it uses small molecule chemicals to regulate biological signals. It is completely defined and therefore more reproducible. And the small molecules are much less expensive than protein growth factors.”