Optogenetic Control of Human Induced Pluripotent Stem Cell‐Derived Cardiac Tissue Models

Abstract

Background Optogenetics, using light‐sensitive proteins, emerged as a unique experimental paradigm to modulate cardiac excitability. We aimed to develop high‐resolution optogenetic approaches to modulate electrical activity in 2‐ and 3‐dimensional cardiac tissue models derived from human induced pluripotent stem cell (hiPSC)‐derived cardiomyocytes. Methods and Results To establish light‐controllable cardiac tissue models, opsin‐carrying HEK293 cells, expressing the light‐sensitive cationic‐channel CoChR, were mixed with hiPSC‐cardiomyocytes to generate 2‐dimensional hiPSC‐derived cardiac cell‐sheets or 3‐dimensional engineered heart tissues. Complex illumination patterns were designed with a high‐resolution digital micro‐mirror device. Optical mapping and force measurements were used to evaluate the tissues' electromechanical properties. The ability to optogenetically pace and shape the tissue's conduction properties was demonstrated by using single or multiple illumination stimulation sites, complex illumination patterns, or diffuse illumination. This allowed to establish in vitro models for optogenetic‐based cardiac resynchronization therapy, where the electrical activation could be synchronized (hiPSC‐derived cardiac cell‐sheets and engineered heart tissue models) and contractile properties improved (engineered heart tissues). Next, reentrant activity (rotors) was induced in the hiPSC‐derived cardiac cell‐sheets and engineered heart tissue models through optogenetics programmed‐ or cross‐field stimulations. Diffuse illumination protocols were then used to terminate arrhythmias, demonstrating the potential to study optogenetics cardioversion mechanisms and to identify optimal illumination parameters for arrhythmia termination. Conclusions By combining optogenetics and hiPSC technologies, light‐controllable human cardiac tissue models could be established, in which tissue excitability can be modulated in a functional, reversible, and localized manner. This approach may bring a unique value for physiological/pathophysiological studies, for disease modeling, and for developing optogenetic‐based cardiac pacing, resynchronization, and defibrillation approaches.

Building blocks of microphysiological system to model physiology and pathophysiology of human heart

“…Instead, here we aim to summarize the effect of physical stimulation on hiPSC-CM maturation. Optogenetic stimulation has also raised interest as maturation tool ( Dwenger et al, 2021 ) but to our knowledge, it is currently only used on modulating tissue excitability by pacing ( Gruber et al, 2022 ). It will therefore be excluded from the scope of this chapter.…”

Guidelines for assessment of cardiac electrophysiology and arrhythmias in small animals

“…For example, contactless “all optical” cardiac electrophysiology techniques use genetically encoded voltage and/or calcium indicators (for optical mapping) in combination with optogenetic actuation to precisely control cardiac excitation via light-sensitive ion channels ( 357 ). All-optical cardiac electrophysiology has been successfully used in vitro using hiPSC-CMs for preclinical drug testing ( 358 , 359 ), assessment of neuron-cardiomyocyte interactions ( 360 ), and modulation of cardiac electrical activity in 2-D/3-D hiPSC-CM preparations ( 361 ) and intact, isolated hearts ( 362 , 363 ). Advancements in microendoscopy ( 364 ) and fabrication of miniaturized LED devices ( 365 ) can be used to optimize light delivery in vivo, and one day, these tools may be used as optical alternatives to electrical devices [e.g., pacemakers, defibrillators ( 366 , 367 )].…”