Geometry-dependent functional changes in iPSC-derived cardiomyocytes probed by functional imaging and RNA sequencing.

Area of Science:

• Cardiovascular Biology
• Stem Cell Biology
• Biomedical Engineering

Background:

• Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) offer a valuable in vitro model for cardiac research and potential therapeutic applications.
• hiPSC-CM often exhibit immature phenotypes, resembling embryonic cardiomyocytes rather than adult cells, limiting their utility.
• Understanding factors that promote hiPSC-CM maturation is crucial for improving their application in disease modeling and regenerative medicine.

Purpose of the Study:

• To investigate the impact of patterned island geometry, specifically size and shape, on the functional maturation of hiPSC-CM.
• To identify molecular signatures associated with size-induced maturation using transcriptional profiling.
• To assess the utility of optical electrophysiology as a tool for quantifying hiPSC-CM maturation.

Main Methods:

• hiPSC-CM were cultured on patterned islands of varying sizes and shapes.
• Optical recordings of voltage and calcium dynamics were performed on 970 individual islands.
• Transcriptional profiling of hiPSC-CM from small and large islands was compared to developmental cardiac differentiation time courses.

Main Results:

• hiPSC-CM cultured on larger islands exhibited enhanced electrical and calcium dynamics, indicative of greater functional maturity.
• Island size significantly influenced the expression of a subset of genes (58% of changes) associated with cardiac maturation.
• Optical electrophysiology proved effective in assaying hiPSC-CM maturation status.

Conclusions:

• Culture on larger patterned islands is a powerful strategy to drive functional and molecular maturation of hiPSC-CM.
• Island size selectively activates specific gene expression programs crucial for achieving a more mature cardiomyocyte phenotype.
• This study highlights the potential of substrate geometry to guide stem cell differentiation and maturation for biomedical applications.