Genetically selected cardiomyocytes from differentiating embronic stem cells form stable intracardiac grafts.

TLDR

The study presents a simple method to generate highly pure cardiomyocyte cultures from differentiating murine embryonic stem cells. The authors engineered ES cells with a cardiac‑promoter driven aminoglycoside phosphotransferase fusion, differentiated them, and used G418 selection to isolate cardiomyocytes, which were then transplanted into dystrophic mouse hearts and tracked by immunohistology and PCR. The G418‑selected cardiomyocytes were >99% pure, highly differentiated, and formed stable intracardiac grafts in dystrophic mice for at least seven weeks, demonstrating that this selection strategy is effective and broadly applicable to ES‑derived cell lineages.

Abstract

This study describes a simple approach to generate relatively pure cultures of cardiomyocytes from differentiating murine embryonic stem (ES) cells. A fusion gene consisting of the alpha-cardiac myosin heavy chain promoter and a cDNA encoding aminoglycoside phosphotransferase was stably transfected into pluripotent ES cells. The resulting cell lines were differentiated in vitro and subjected to G418 selection. Immunocytological and ultrastructural analyses demonstrated that the selected cardiomyocyte cultures (> 99% pure) were highly differentiated. G418 selected cardiomyocytes were tested for their ability to form grafts in the hearts of adult dystrophic mice. The fate of the engrafted cells was monitored by antidystrophin immunohistology, as well as by PCR analysis with primers specific for the myosin heavy chain-aminoglycoside phosphotransferase transgene. Both analyses revealed the presence of ES-derived cardiomyocyte grafts for as long as 7 wk after implantation, the latest time point analyzed. These studies indicate that a simple genetic manipulation can be used to select essentially pure cultures of cardiomyocytes from differentiating ES cells. Moreover, the resulting cardiomyocytes are suitable for the formation of intracardiac grafts. This selection approach should be applicable to all ES-derived cell lineages.