Abstract 357: Role of Combinatorial Extracellular Matrix Proteins in Modulating Endothelial Differentiation of Human Induced Pluripotent Stem Cells

Human induced pluripotent stem cell (iPSC)-derived endothelial cells (iPSC-ECs) are promising for promoting angiogenesis in patients with cardiovascular disease, but a critical bottleneck is the ability to generate iPSC-ECs at high yields. Since endothelial cells physiologically interact with a milieu of basement membrane extracellular matrix (ECM) proteins, we aimed to examine the role of combinatorial ECMs in modulating endothelial differentiation using engineered ECM microenvironments. ECMs consisting of (gelatin (G), fibronectin (F), laminin (L), heparan sulfate proteoglycan (H), collagen IV (C), matrigel (M)) and the multi-component combinations thereof were conjugated onto glass slides to generate ECM microarrays composed of 63 unique combinatorial ECMs. Human iPSCs were differentiated on the ECM microarray for 5 days, and differentiation was quantified based on the degree of CD31 staining. Heat map analysis of CD31expression was significantly higher on G+M+L, compared to other combinations across 2 iPSC lines (Figure). RT-PCR further confirmed the upregulation in endothelial markers CD31 (>2-fold) and VE-cadherin (> 4-fold) when differentiated on G+M+L, compared to other ECMs. To elucidate the underlying mechanism, upregulation of endothelial genes were associated with upregulation of integrins (α1, α4, α5, αV, β1, β3, and β4) during the differentiation process. This data suggests a role of ECM-mediated integrin expression in modulating endothelial differentiation. Together, this data suggested that combinatorial ECMs differentially promote endothelial differentiation, in part through integrin-mediated pathways.