Experimental and Computational Modeling for Directing Vascular Fate

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Experimental and Computational Modeling for Directing
Vascular Fate

DE Glaser, WS Turner, L Wong, J Zamora, KE McCloskey, Ph.D.

University of California, Merced, CA

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Embryonic
stem cells (ESC) and induced pluripotent stem (iPS) cells and are attractive in
vitro models of vascular development, therapeutic angiogenesis, and tissue
engineering. Although a number of biochemical signals have been identified for
directing endothelial fate, many of these factors activate redundant pathways,
and the minimal combinatorial signals directing vascular fate have yet to be
elucidated. Using our stage-specific chemically-defined derivation methodology,
we examined multiple combinatorial factors for directing vascular smooth muscle
cell (SMC) versus endothelial cell (EC) fate including: kinetics, cell seeding
density, matrix signaling, matrix stiffness as well as medium treatment with
vascular endothelial growth factor (VEGF), and basic fibroblast growth factor
(bFGF). Combined with computational modeling, we have been able to identify the
most potent interacting variables directing Flk-1+/KDR+ vascular progenitor
cells (VPC), calponin+ SMC and VE-cad+ EC. The results indicate that temporal
development in each of these stages is the most significant factor generating
the desired cells. The generation of Flk-1+/KDR+ VPC from pluripotent ESC is
directed predominantly by high cell seeding density and matrix signaling from
fibronectin, while VEGF supplementation was shown to be superfluous. Additionally,
stiffer materials directed more SMC while softer materials (10kPa) directed
more EC. These results can now be applied towards the codifferentation of the
two cells types in 3D materials for acquiring stable perfusable vasculature.