Micropatterned Co-cultures of the Liver and the Heart for Drug Screening and Cell Therapy

In vivo animal studies are useful for evaluating a small number of compounds during the later stages of preclinical development. In comparison, tissue engineering allows for the ability to obtain high throughput and human relevant data utilizing small amounts of cellular material. Two main organs of interest remain the liver and heart, not only because they are the leading cause of drugs failing in clinical trials due to drug induced liver injury (DILI) or cardiotoxicity concerns, but also because they are key contributors to global diseases including atrial fibrillation (AF) and hematopoietic stem cell (HSC) expansion through extramedullary hematopoiesis (EmH). Optimal platforms should maintain stable functionality, allow for genetic diversity, and remain human relevant. However, conventional hepatocyte cultures decline in phenotype and cardiomyocytes do not form optimal cell-cell junctions, leading to random beating. Thus, there remains a need to further improve these platforms. To this end, we determined two techniques useful for stabilizing key cell types, namely micropatterning to improve homotypic interactions and coculture with specific fibroblast populations. To begin, current in vitro platforms lack the ability to investigate genetic variation in the human population as donor tissue is limited. Advances in mouse genetics have been shown to recapitulate human toxicity for certain drug classes; therefore, we aim to create a robust mouse liver platform utilizing the above-mentioned techniques to maintain hepatocyte functionality, which can also be utilized prior to in vivo animal studies to verify human relevance in drug metabolism. For this purpose, a platform utilizing human hepatocytes and portal fibroblasts was created to determine if a stable hepatocyte phenotype can be achieved with liver specific fibroblasts. We will then utilize these platforms to study HSC expansion in a liver microenvironment to replicate key factors of EmH. Finally, we will utilize iPSC-derived atrial cardiomyocytes (iPSC-aCMs) as a genetically diverse and patient specific cell source for the study of genetic variation in AF by improving maturation through micropatterning and coculture with cardiac fibroblasts. Ultimately, the micropatterned coculture liver and atrial cardiac platforms developed in this thesis can be used to study novel therapeutics and allow for fundamental investigations into disease mechanisms.