Cao, N. et al. Science 352, 1216–1220 (2016).

Although the conversion of human somatic cells to cardiomyocyte (CM)-like cells has been reported previously, existing methods involve at least one exogenously expressed gene. Recent work from Cao et al. describes chemical induction of CM-like cells from human foreskin or lung fibroblasts. After an iterative screening process based in part on prior knowledge, the researchers identified a cocktail of nine small molecules that, in combination with growth factors, result in 6–7% of treated cells expressing the CM marker cardiac troponin T. The resulting ciCMs (chemically induced CM-like cells) are similar molecularly and functionally to human pluripotent stem cell–derived CMs. Furthermore, in vitro treatment of fibroblasts with the nine-chemical cocktail yielded cells that resembled CMs when transplanted in vivo into the infarcted heart of an immunodeficient mouse.