Figure 2.

Cardiac Maturation Defects in Lmna^Δ/Δ Mice

(A) Bright-field images of hearts extracted from 6-week-old mice. (B,C) Echocardiogram analysis of the 6-week-old mice. (D) Immunostaining of ACTN2 on isolated cardiomyocytes and quantification of the distances between adjacent Z-lines. (E) Quantification of cardiomyocyte projected cell area, cell length, and cell width. (F) DAPI (4′,6-diamidino-2-phenylindole)-stained cell nuclei and quantification of nuclear morphology. (G) Representative traces of sarcomere length changes during cardiomyocyte contraction on 1 Hz electrical stimulation. (H) Quantification of contractility parameters. (D-H) Cells from littermates were compared. (B to H) Mann-Whitney U test; ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001, NS. (I) Gene set enrichment analysis of the differentially expressed genes by RNA-sequencing. (J) Enrichment of cardiac mature markers among down-regulated genes in Lmna^Δ/Δ ventricles. (K) Quantification of cardiomyocyte maturation isoform switching markers in RNA-sequencing data. FDR = false discovery rate; FS = fractional shortening; LVIDd = left ventricular internal diameter in diastole; LVIDs = left ventricular internal diameter in systole; LVPWd = left ventricular posterior wall in diastole; LVPWs = left ventricular systolic posterior wall in systole; NES = normalized enrichment score.