Abstract Thu048: Impact of ECM Proteins on Cardiac Differentiation of Pluripotent Stem Cells: Using Chamber-Specific Nanofibrous Matrices to guide Cardiomyocyte Development

Introduction: Decellularized extracellular matrix (dECM) is a natural biomaterial rich in tissue-specific proteins, retaining the tissue's memory. Recent studies emphasize the significance of cardiac dECM in differentiating induced pluripotent stem cells (iPSCs) into cardiac lineages. This research investigates compositional differences among cardiac chambers by analyzing chamber-specific proteins and their influence on developing chamber-specific cardiomyocytes (iPSC-CMs). The study fabricates electrospun matrices to boost iPSC differentiation using porcine myocardial dECM from atrial and ventricular regions. It examines how native proteins affect differentiation, aiming to advance regenerative medicine to repair or replace damaged cells and tissues, enhancing existing practices through innovation. Methods/Results: The porcine heart was dissected to isolate atrial and ventricular regions (Fig. 1, A-B). Fig. 1, C-D shows differences in fresh tissue, which was decellularized and electrospun into fibrous mesh. LS-MS analysis of decellularized tissue revealed about 300 distinct proteins in the atrial region versus 1,000 in the ventricular region. Electrospun adECM samples had a smaller fiber diameter (Fig. 1E) and a modulus of 60±15 kPa, while ventricular samples had a larger diameter (Fig. 1F) and a lower modulus of 42±15 kPa. Cellular interaction was assessed by seeding samples with undifferentiated iPSCs, differentiated towards cardiac lineage via WNT modulation. Chamber-based markers were evaluated using RT-qPCR, showing increased chamber-specific markers. Atrial cardiomyocyte markers like MLC2a and MYH6 were upregulated at d15 in adECM samples without specific atrial cell differentiation. Ongoing investigations include functional analysis and ion channel analysis. Conclusion: This study highlights the influence of protein composition on the differentiation of iPSCs into chamber-specific cardiomyocytes, streamlining the production of distinct CM populations.