Deriving Cardiomyocytes from Human Amniocytes

Many forms of congenital heart disease (CHD) have high morbidity-mortality rates and require challenging surgeries. Human amniocytes have important stem cell characteristics and could potentially provide patient-specific tissue for repairs of some types of CHDs. We report that amniocytes express features of poised cardiomyocytes. However, a variety of direct reprogramming approaches failed to convert their fetal and transcriptionally repressed state into bona fide cardiomyocytes. Induced-pluripotent stem cell (iPSC) reprogramming removes repression and converts amniocytes to a baseline pluripotent state. Based on molecular and electrophysiological signatures, iPSC reprogrammed amniocytes can be induced to differentiate into functionally immature, predominantly ventricular cardiomyocytes and a heterogeneous mixture of vascular and unspecified epithelial cells. Developmental time course analyses and pattern clustering of amniocyte-derived cardiomyocytes identifies numerous temporal co-regulators of cardiac induction and maturation as well as distinct sarcomeric and ion channel gene signatures. Normal fetal cardiomyocytes are derived by overcoming complex forms of transcriptional repression that suppress direct transdifferentiation of human amniocytes. These results suggest the possibility of using amniocytes as a source of patient-specific ventricular cardiomyocytes for cell therapies.