Real-time and Multichannel Measurement of Contractility of hiPSC-Derived 3D Skeletal Muscle using Fiber Optics-Based Sensing

As the field of cardiac and skeletal muscle tissue engineering expands, so does the need for accurate and reliable systems to generate in vitro 3D tissues and analyze their functional properties. In this study, the Cuore is introduced, a system that integrates sensors based on optical fibers and uses the principle of light interferometry to detect the contraction of 3D Tissue Engineered Skeletal Muscles (3D-TESMs). The technology employed in the Cuore allows for reproducible and multichannel force measurements down to a nano-Newtons resolution while maintaining sterility and permitting continuous non-invasive recording within and outside standard tissue culture incubators. Thanks to the integrated electrodes for electrical pulse stimulation (EPS), 3D-TESMs generated from three independent hiPSC-derived myogenic progenitors (MPs) lines are stimulated and the contractility is recorded over the course of a week. Through the modulation of different EPS parameters, the optimal combination to induce the 3D-TESMs in producing fully fused tetani without causing damage is determined. Furthermore, 3D-TESMs from different lines exhibit characteristic signatures of spontaneous contractility and response to caffeine, verapamil, and the β-agonist clenbuterol. The ease of use, high sensitivity, and the integrated electrodes and sensors make the Cuore an ideal technology to investigate the biology of contractile tissues and their response to drugs.</p

Highly contractile 3D tissue engineered skeletal muscles from human iPSCs reveal similarities with primary myoblast-derived tissues

Skeletal muscle research is transitioning toward 3D tissue engineered in vitro models reproducing muscle's native architecture and supporting measurement of functionality. Human induced pluripotent stem cells (hiPSCs) offer high yields of cells for differentiation. It has been difficult to differentiate high-quality, pure 3D muscle tissues from hiPSCs that show contractile properties comparable to primary myoblast-derived tissues. Here, we present a transgene-free method for the generation of purified, expandable myogenic progenitors (MPs) from hiPSCs grown under feeder-free conditions. We defined a protocol with optimal hydrogel and medium conditions that allowed production of highly contractile 3D tissue engineered skeletal muscles with forces similar to primary myoblast-derived tissues. Gene expression and proteomic analysis between hiPSC-derived and primary myoblast-derived 3D tissues revealed a similar expression profile of proteins involved in myogenic differentiation and sarcomere function. The protocol should be generally applicable for the study of personalized human skeletal muscle tissue in health and disease.</p