Fig. 4

Fig. 4

Vcl Is Required for Myofilament Maturation and Myocardial Wall Integrity in Response to Cardiac Contractility

(A) 3D images of 107 hpf hearts. vclb^−/− and DN Vcl-EGFP expressing CMs exhibit disorganized and thinner myofilaments than WT (arrowheads). Myofilament thickness measured in 107 hpf ventricles (n = 5 ventricles).

(B) 3D images of 77 hpf hearts. CA Vcl-tdTomato⁺ ventricles exhibit thicker and more aligned myofilaments than WT (arrowheads). Myofilament thickness measured in 77 hpf ventricles (n = 4 ventricles).

(C) 3D images of 98 hpf ventricles treated with DMSO or IBMX from 74 to 98 hpf. IBMX treatment leads to further myofilament disruption in vclb^−/− ventricles than DMSO treatment (arrowheads). Myofilament thickness measured in 98 hpf ventricles (n = 4–5 ventricles).

(D) Single-plane images of 102 hpf ventricles treated with IBMX from 78 to 102 hpf. IBMX treatment leads to CM extrusion (arrowhead) in vclb^−/− ventricles. Number of extruding CMs measured in 102 hpf ventricles (n = 5 ventricles).

(E) Schematic of the transplantation experiment.

(F) Single-plane images of 127 hpf chimeric hearts treated with IBMX from 103 to 127 hpf. vclb^−/− CMs extrude in chimeric hearts (arrowheads). Percentage of extruding CMs in 127 hpf chimeric ventricles (n = 5 ventricles).

(G) Schematic of the transplantation experiment.

(H) Single-plane images of 127 hpf chimeric hearts. tnnt2a morphant CMs extrude in chimeric ventricles (arrowheads). Percentage of extruding CMs in 127 hpf chimeric ventricles (n = 5 ventricles). Error bars, SEM. ^∗p < 0.05 and ^∗∗p < 0.001 by ANOVA followed by Tukey’s HSD test. Scale bars, 10 μm in (B)–(D); 20 μm in (A), (F), and (H).