Figure 4.
Electron microscopy of Control (A, D, G), CPVT1-RyR2R420Q (B, E, H) and CPVT2-CASQ2D307H (C, F, I) iPSC-CM. (A–C) show overall appearance of EBs. Nuclei (N), clusters of mitochondria (m), myofilaments (mf), glycogen masses (g), lysosomes (L) are visible in cytoplasm of cardiomyocytes. (D–F) Electron microscopy of the myofilaments (mf) organized in distinct sarcomeric structures defined by Z-bands. m - mitochondria, g - glycogen, L - lysosomes. (G–I) Electron microscopy of peripheral sarcoplasmic reticulum (SR) of cardiomyocytes. g: glycogen; m: mitochondria; mf: myofilaments; Z band, c: caveolae; ecs: extracellular space. Arrowheads indicate RyR between SR and sarcolemma.