Probing Subcellular Nanostructure of Engineered Human Cardiomyocytes in 3D Tissue

TL;DR

This study uses small angle X-ray scattering to reveal detailed subcellular structures in engineered human heart tissue, correlating structural features with contractile function and disease mutations.

Contribution

It demonstrates the first detection of myofilament lattice periodicity in 3D engineered human cardiomyocytes using SAXS, linking structural maturation to functional properties.

Findings

Myofilament lattice periodicity detected in 3D hiPSC-CMs.

Contractile force correlates with scattering intensity and lattice spacing.

Decreased myofilament order observed in hypertrophic cardiomyopathy mutation tissues.

Abstract

The structural and functional maturation of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) is essential for application to pharmaceutical testing, disease modeling, and ultimately therapeutic use. Multicellular 3D-tissue platforms have improved functional maturation of hiPSC-CMs, but probing cardiac contractile properties remains challenging in a 3D environment, especially at depth and in live tissues. Using small angle X-ray scattering (SAXS) images, we show that hiPSC-CMs, matured and examined in a 3D environment, exhibit periodic spatial arrangement of the myofilament lattice, which has not been previously detected in hiPSC-CMs. Contractile force is found to correlate with both scattering intensity (R2=0.44) and lattice spacing (R2=0.46). Scattering intensity also correlates with lattice spacing (R2=0.81), suggestive of lower noise in our structural measurement relative to the functional measurement. Notably, we observe decreased myofilament ordering in tissues with a myofilament mutation known to lead to hypertrophic cardiomyopathy (HCM). Our results highlight the progress of human cardiac tissue engineering and enable unprecedented study of structural maturation in hiPSC-CMs.