Extracellular Matrix Guided Endothelial Differentiation

Abstract

Cardiovascular disease is the leading cause of death worldwide. Due to recent advances including development of induced pluripotent stem cells, cardiac tissue engineering has emerged as a promising avenue for in vitro drug and device testing as well as eventual transplantation. Nutrient flow presents one of the major challenges to large scale engineered cardiac tissues which is necessary for many of the potential applications of engineered tissues. The lack of nutrient flow could be solved through tissue vascularization which requires endothelial cells lining vessels. The extracellular matrix (ECM) plays a vital role in tissue development and the majority of in vitro differentiation protocols rely on ECM substrates. Here we present two studies which investigate the role of the ECM in endothelial differentiation and the mechanisms activated by ECM engagement during differentiation. First, we investigate the role of individual ECM proteins in endothelial differentiation and elucidate pathways key to how ECM interactions promote differentiation. Second, a Design of Experiments approach was utilized to optimize the ECM composition for endothelial differentiation. The foundation of this work is a thorough knowledge of the role of the ECM during development, which guides protein selection and mechanistic investigation. An improved understanding of the role of ECM during in vitro differentiation will lead to better differentiation protocols and the potential for in situ differentiation. Ultimately, these studies will inform methods for engineered tissue vascularization to improve cell survival in large scale engineered tissues.