Improvement in mitochondrial oxidative phosphorylation of cardiomyocytes derived from human-induced pluripotent stem cells using micropatterned anisotropic substrates

Abstract

Abstract Background/Introduction Alterations in cellular bioenergetic events owing to metabolic dysfunctions are well demonstrated in heart failure (HF). Cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CMs) have the potential to model metabolic alterations as observed in the human failing hearts, which however requires precise arrangements of the respiratory chain complexes. Purpose Develop a method to improve the hiPSC-CMs architecture by using a micropatterned substrate (repeated lines of 30 μm-width separated with a cell repellant) that promotes elongation and anisotropy. Methods Cardiomyocyte differentiation was performed using a chemically defined method and 35 days later the generated hiPSC-CMs were cultured on unpatterned vs. micropatterned substrates for 7 additional days. Energy metabolic profiles were then measured using the Seahorse analyzer and mitochondrial components were analyzed by fluorescence microscopy and western blot. Results Cultures on micropatterned anisotropic substrates resulted in the generation of elongated cell morphology, rod-shaped hiPSC-CMs with improved sarcomere organization scores, and more aligned Z-lines. We first found a specific increase in oxidation phosphorylation (OXPHOS) activity in micropatterned CMs with a significant increase in the oxygen consumption rate (OCR) linked to basal respiration (58.4±24.0 vs 40.6±21.0 pmol/min, p<0.01), ATP production (49.6±19.1 vs 33.2±18.8 pmol/min, p<0.001) and maximal respiration (239.1±119.0 vs 123.0±68.5 pmol/min, p<0.001). Micropatterned CMs showed a better electron transport chain activity that explains the significantly decreased glycolytic function observed by Seahorse (17.2±9.9 vs 23.9±7.2 mpH/min, p<0.001). Micropatterned CMs displayed a more organized mitochondrial network, without evident change in mitochondrial mass. Transcriptomic profiling of micropatterned vs. unpatterned CMs revealed no significant differences. We next evaluated the proteomic profiling and found no significant change in the micropatterned CMs OXPHOS proteins expression. Conclusion(s) We developed a novel method for modeling metabolic activity in hiPSC-CMs based on micropatterned cultures. Our data show that the linear architectural pattern drives the formation and efficiency of OXPHOS function in cardiomyocytes with a mitochondrial structural reorganization. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Agence Nationale de la Recherche