Cardiomyocytes derived from human-induced pluripotent stem cells (iPS-CMs) have the potential to model metabolic alterations observed in the human failing hearts, this however requires precise arrangements of the respiratory chain complexes.

Improve iPS-CMs architecture by using a micropatterned anisotropic substrate (repeated lines of 30μm-width separated with a cell repellant)

Cardiomyocyte differentiation was performed using a chemically defined method. Thirty-five days later the generated iPS-CMs were cultured on unpatterned vs. micropatterned substrates for 7 days. Energy metabolic profiles were measured using the Seahorse analyzer and mitochondrial components analyzed by fluorescence microscopy and western blot.

Micropatterned culture resulted in the generation of elongated, rod-shape iPS-CMs with improved sarcomere organization score and more aligned Z-lines. We found a specific increase in oxidation phosphorylation (OXPHOS) activity in micropatterned CMs with significant increase in the oxygen consumption rate linked to basal respiration (58.4±24.0 vs. 40.6±21.0pmol/min, P<0.01), ATP production (49.6±19.1 vs. 33.2±18.8pmol/min, P<0.001) and maximal respiration (239.1±119.0 vs. 123.0±68.5pmol/min, P<0.001). Micropatterned CMs displayed a more organized mitochondrial network, without evident change in mitochondrial mass. A transcriptomic profiling of micropatterned vs. unpatterned CMs revealed no significant differences. We next evaluated the proteomic profiling and found an upregulation of OXPHOS proteins in the micropatterned CMs with specific increase in complexes I though IV that explain the enhanced mitochondrial respiration and increased membrane potential observed by microscopy.

We developed a novel method for modeling the metabolic activity in iPS-CMs based on micropatterned culture. Our data show that the linear architectural pattern drives the formation and efficiency of OXPHOS function in cardiomyocytes.