innoVation Facts – Cardiac Maturation Cues (Part 2)

In our second part of the innoVation Facts series addressing cardiac maturation cues, we focus on phenotypic changes that take place when human iPSC-cardiomyocytes (hiPSC-CMs) are cultured on FLEXcyte 96 plates to emulate the physiological conditions of the human heart.

To visualize changes in actin filament development, staining with Phalloidin was performed on Cardiosight-s (Nexel Ltd.) hiPSC-CMs plated on FLEXcyte 96 plates for 7 days and 17 days. (Scale bars = 20µM)

The staining shows a clear change in actin development from fine structures at days 7 to more pronounced filaments including typical striation, indicating the establishment of sarcomers (Fritz-Six et al., 2003; Chu et al., 2003; Ehler et al., 2004).

Chu X, Chen J, Reedy MC, Vera C, Sung KL, Sung LA (2003) E-Tmod capping of actin filaments at the slow-growing end is required to establish mouse embryonic circulation. Am J Physiol Heart Circ Physiol 284:H1827–H1838

Ehler E, Fowler VM, Perriard JC (2004) Myofibrillogenesis in the developing chicken heart: role of actin isoforms and of the pointed end actin capping protein tropomodulin during thin filament assembly. Dev Dyn 229:745–755

Fritz-Six KL, Cox PR, Fischer RS, Xu B, Gregorio CC, Zoghbi HY, Fowler VM (2003) Aberrant myofibril assembly in tropomodulin1 null mice leads to aborted heart development and embryonic lethality. J Cell Biol 163:1033–1044