However, when we overexpressed the nucleus-targeted isoform CaMKIIδB in hESC-VCMs, we found that CaMKIIδB could indeed induce cardiac hypertrophy through nuclear Ca2+/CaMKIIδB/HDAC4/MEF2 pathway (Figure 7 and Figure S9). Here, HDAC4 is linked to cardiac hypertrophy.