Myocardial disarray drives metabolic inefficiency in human cardiomyocytes

Area of Science:

• Cardiovascular Biology
• Cellular Metabolism
• Biophysics

Background:

• Adult cardiomyocytes possess a unique morphology dictated by their microenvironment.
• Cardiomyocyte disarray is linked to heart disease, but its functional impact is unclear.
• Understanding cardiomyocyte organization is crucial for cardiac health.

Purpose of the Study:

• To investigate the functional consequences of cardiomyocyte structural organization.
• To explore how mechanical alignment affects mitochondrial form and function in hiPSC-CMs.
• To elucidate the role of cellular architecture in cardiomyocyte bioenergetics.

Main Methods:

• Utilized micropatterned substrates to induce structural alignment in hiPSC-CMs.
• Compared aligned hiPSC-CMs with those cultured under standard unconstrained conditions.
• Assessed sarcomere and mitochondrial organization, respiration, and mitochondria-associated membranes via microscopy and assays.

Main Results:

• Micropatterned hiPSC-CMs showed aligned sarcomeres and reorganized mitochondria, enhancing mitochondrial respiration.
• Mitochondrial respiration increased without a corresponding rise in mitochondrial mass.
• Aligned cells exhibited more mitochondria-associated membranes, indicating enhanced sarcoplasmic reticulum-mitochondria interactions.

Conclusions:

• Mitochondrial-sarcoplasmic reticulum architecture and cellular geometry are vital for cardiomyocyte bioenergetic efficiency.
• Cellular organization significantly impacts cardiomyocyte metabolism and function.
• This study provides insights into cardiac diseases characterized by cellular disorganization.