Discipline: Biological Sciences
Subcategory: Biomedical Engineering
Room: Exhibit Hall A
Kaiya Mitchell - Georgia Institute of Technology
Co-Author(s): Ana Reyes, University of Puerto Rico - Mayaquez, Mayaquez, PR; Maribella Domenech, University of Puerto Rico at Mayaguez, Mayaguez, PR
Cardiovascular disease is the leading cause of mortality worldwide while heart failure is the principal cause of hospital admissions in the United States. The heart’s incapacity to regenerate new tissue is the main barrier to treating heart diseases. Studies indicate that human-induced pluripotent stem cells (hiPSCs) could be directed to generate cardiomyocytes, representing an auspicious class of emerging treatments to combat cardiac cell mortality and provide a novel strategy to restore damaged or lost tissue. A limitation for this cell therapy is that current differentiation strategies fail to yield high percentages of mechanically-coupled adult cardiomyocytes. Research shows that substrates could potentially enhance the maturation of cardiomyocytes. Ideally, substrates should be anisotropic to accurately mimic the structure and function of the heart, made possible through the alignment of elongated cardiomyocytes with their surrounding extracellular matrix. Here we hypothesized that the use of tissue-like anisotropic substrates could potentially optimize the cardiac differentiation process. In this investigation, collagen-based anisotropic substrates were fabricated through electrospinning and 25%glutaraldehyde-crosslinking processes. Crosslinked collagen substrates were characterized using Fourier Transform InfraRed spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). WTC11 (specific hiPSC line) cells were cultured on Matrigel-treated plates until fully confluent, then passaged to experimental culture plates where cells were treated with small molecule inhibitors of the Wnt signaling pathway (group of signal transduction pathways) to promote cardiac differentiation on anisotropic collagen substrates in standard culture wells. Cardiac differentiation rates were evaluated on collagen substrates and compared to commercial surface coatings (CSCs), Matrigel and Fibronectin. Expression of cell stemness using octamer-binding transcription factor 4 (Oct-4) and cardiac marker, Cardiac Troponin (cTnT) were examined at days 4 and 15 respectively. The analysis of collagen substrates confirmed the fibrillar organization of the substrate and the presence of the functional groups associated with the triple-helical structure. Examination of Oct-4 and cTnT expression in WTC11 cells indicated that collagen substrates produced a high yield of virtually pure (~80%) cardiomyocytes compared to ~50% cardiomyocytes on CSCs. Viability and cell growth tests showed that collagen substrates produced ~500,000 cells/cm2 while CSCs produced 1-1.75 million cells/cm2. In conclusion, collagen substrates enhanced the percent of cardiomyocytes, however, the total cells on collagen conditions suggests that collagen could be affected during the culturing process, generating lower cell growth. Our future endeavors are to investigate the potential cause of the low cell count of WTC11 cells on collagen substrates and evaluate how collagen may be affected during the process.
Funder Acknowledgement(s): This material is based upon work supported by the National Science Foundation under Grant No. 1648035 ; (ERC-CMaT) at the University of Puerto Rico - Mayaquez in the Domenech Lab
Faculty Advisor: Maribella Domenech, email@example.com
Role: For this research, I fabricated collagen substrates and characterized them using Fourier Transform InfraRed spectroscopy (FTIR). I cultured WTC11 cells on Matrigel-treated plates and passaged them to experimental culture plates that I prepared myself and differentiated the cells into cardiomyocytes using the small molecule Wnt signaling pathway. I then analyzed the quality of cardiac differentiation on collagen substrates and commercial surface coatings, Matrigel and Fibronectin, by marking the cardiomyocytes with Oct-4 and cTnT and analyzed their expression. I also performed viability and cell count tests on differentiated and undifferentiated WTC11 cells.