45Background: The renin-angiotensin system (RAS) functions 46 fundamentally to regulate the pathological process of cardiovascular 47 diseases, such as heart failure and hypertension. As the major effector in 48 RAS, angiotensin II activates angiotensin II receptors to initiate the 49 downstream pathways, which lead to the phenotypes including apoptosis, 50 hypertrophy, and cardiac remodeling. Human induced pluripotent stem 51 cell-derived cardiomyocytes (iPSC-CM) are being applied as a promising 52 platform for personalized medicine to heart diseases. However, whether 53 angiotensin II induces apoptosis in iPSC-CM is still obscure, which raises 54 an uncertainty about the clinical applications of iPSC-CM. 55 Methods: We treated iPSC-CM with angiotensin II at eight concentrations 56 (0 nM, 1 nM, 10 nM, 100 nM, 1 μM, 10 μM, 100 μM and 1 mM) and four 57 incubation durations (24 hours, 48 hours, 6 days and 10 days), then 58 PrestoBlue reagent and a apoptosis marker were used to examine the 59 viability and apoptosis status of cardiomyocytes from each group. The 60 expression levels of some apoptosis and proliferation related genes were 61 also analyzed. 62 Results: High concentration angiotensin II with a long-term treatment 63 caused apoptosis and cell viability drop-off in iPSC-CM. Specifically, 64under a 10-day treatment with 1 mM angiotensin II, the viability of iPSC-65 CM was reduced by an average of 41% (p=2.073E-08), and the percentage 66 4 of apoptotic cells was 2.74 times higher than the controls averagely 67 (p=6. 248E-12). The data mining of previous RNA-seq data revealed that 68 angiotensin II receptor type I was the major receptor in iPSC-CM. 69 Conclusions: For the first time, our data confirmed the apoptotic effect of 70 angiotensin II to iPSC-CM. The angiotensin II concentrations and exposure 71 time for apoptosis induction were depicted in our study, which provided 72 supports to iPSC-CM as an in vitro model for cardiovascular disease study.73 74