The expression of ERBB2 interacting protein ERBB2IP (ERBIN), which is important for ERBB2 stabilization and NRG1 signaling (Tao et al., 2009) and is considered as a negative modulator of pathological cardiac hypertrophy (Rachmin et al., 2014), was expressed in both cell types, and increased in co-culture hiPS-ECs (Supplementary Figure 7 and Supplementary Table 1). This evidence concerns the gene NRG1 and cardiac hypertrophy.