Fig. 3

Characterization of cardiomyocytes generated from hypoimmunogenic hPSCs. A Schematic of the protocol and stages for the cardiac differentiation of hPSCs. B Representative immunofluorescence images of NKX2.5 on day 8 of cardiac differentiation of WT and hypoimmunogenic hPSCs. Scale bar, 25 μm. C Bright-field images showing cardiomyocytes morphology derived from WT and hypoimmunogenic hPSCs. Scale bar, 50 μm. D Representative immunofluorescence images of cTnT at 3 weeks of cardiac differentiation. Scale bar, 25 μm. E FACS quantification showing percentages of differentiated cTnT⁺ cardiomyocyte-like cells. Data are represented as mean ± SEM. n.s., no significance, n = 3, Student’s t test. F Representative immunofluorescence images of sarcomere organization by α-actinin and MLC2a staining. Scale bars, 25 μm. G MLR analysis showing relative proliferation of PBMCs after coculturing with cardiomyocytes differentiated from WT, B2M^null, B2M^mHLAG, and B2M^m/sHLAG hPSCs. PBMCs cultured only were used as a negative control (NC). Data are presented as mean ± SEM. **p < 0.01, n = 3, Student’s t test. H Representative recordings of ventricular-like action potentials using whole-cell patch clamp from cardiomyocytes differentiated from WT and hypoimmunogenic hPSCs. Dotted line indicates 0 mV. Right, single action potential at an expanded timescale taken from traces on the left. I–M Comparison of rest membrane potential (RMP, I), action potential amplitude (APA, J), maximal rate of depolarization (dV/dt_max, K), action potential duration (APD) at 90% repolarization (L) and 50% repolarization (M) in cardiomyocytes differentiated from WT and hypoimmunogenic hPSCs. Data are represented as mean ± SEM. n.s., no significance, n (WT) = 11, n (B2M^null) = 11, n (B2M^mHLAG) = 20, n (B2M^m/sHLAG) = 11, Student’s t test