(190j) Cell Population Balance of Cardiovascular Spheroids Derived from Human Induced Pluripotent Stem Cells

Cell population balance of cardiovascular spheroids derived
from human induced pluripotent stem cells

Julie Bejoy^#, Yuanwei Yan^#, Junfei
Xia, Kyle Griffin, Jingjiao Guan, Yan Li*

Department of Chemical and Biomedical Engineering, FAMU-FSU
College of Engineering, Florida State University, Tallahassee, Florida, USA

Abstract:

Stem cell-derived cardiomyocytes and vascular cells can be used for a
variety of applications such as studying human heart development and modelling
human disease in culture. In particular, protocols based on modulation of Wnt
signaling were able to produce high quality of cardiomyocytes or vascular cells
from human pluripotent stem cells (hPSCs).  However, the mechanism behind the
development of cardiovascular spheroids into either vascular or cardiac cells
has not been well explored.  Hippo/Yes-associated protein (YAP) signaling plays
important roles in the regulation of heart size during organogenesis, but its
impact on cardiovascular differentiation has been less evaluated.  In this
study, the impacts of seeding density and the modulation of Hippo/YAP signaling
on cardiovascular spheroid patterning were evaluated.  The undifferentiated
cells were seeded at different densities and Hippo/YAP signaling was modulated
using ROCK inhibitor or Cytochalasin D (Cyto D).  Compared to 2-D culture, 3-D
cardiovascular spheroids exhibit higher levels of sarcomeric striations and
higher length-to-width ratios of α-actinin+ cells.  The cells with higher
seeding density exhibit a higher expression level of CD31 but a lower level of
VE-cadherin with less nuclear YAP expression.  Cyto D treatment results in more
cytoplasmic YAP and lower CD31 expression compared to ROCK inhibitor,
indicating the roles of Hippo/YAP pathway in cardiovascular spheroid patterning. 
The gene expression of MMP-2, MMP-3, and Notch-1 was further analyzed.  The
results should help our understanding of the underlying effects for the
efficient patterning of cardiovascular spheroids after mesoderm formation from
pluripotent stem cells.