GJA1 and ischemia: This same pattern held when analyzing membranous Cx43 immunoreactivity: Cx43-S3E hPSC-CMs showed 0.61 ± 0.05-fold less membranous Cx43 than WT CMs at baseline, and they showed an even greater reduction in membranous Cx43 following ischemia (with membranous Cx43 in Cx43-S3E and WT hPSC-CMs declining to 0.26 ± 0.04 and 0.70 ± 0.09-fold of baseline WT controls, respectively) (Figure 2C).