Quantifying Cardiomyocyte Size via WGA Staining

WGA staining and quantification was performed as per prior report^{[3 (link)]}. Briefly, the slides were incubated with WGA conjugated to Alexa Fluor 488 (50 mg/mL, Life Technologies) for 1 h at room temperature following PBS washes. To quantify the cross-sectional cardiomyocyte cell size, three to four independent hearts per genotype/group were captured at 40× magnification from three different views and positions (e.g., right ventricle, left ventricle, septum). Cellprofiler was used to quantify the size of cardiomyocytes, which were round and had a nucleus^{[4 ]}. Quantification of at least 500 cells per sample was performed. For cell size after MI, WGA-Alexa Fluor 647 (Thermo Fisher W32466) was used with DAPI counterstain; 50 cells per sample were counted.