Stem Cell-Derived Endothelial Cell Model that Responds to Tobacco Smoke Like Primary Endothelial Cells

To
clarify how smoking leads to heart attack and stroke, we developed
an endothelial cell model (iECs) generated from human induced Pluripotent
Stem Cells (iPSC) and evaluated its responses to tobacco smoke. These
iECs exhibited a uniform endothelial morphology, and expressed markers PECAM1/CD31, VWF/ von Willebrand Factor,
and CDH5/VE-Cadherin. The iECs also exhibited tube
formation and acetyl-LDL uptake comparable to primary endothelial
cells (EC). RNA sequencing (RNA-Seq) revealed a robust correlation
coefficient between iECs and EC (R = 0.76), whereas
gene responses to smoke were qualitatively nearly identical between
iECs and primary ECs (R = 0.86). Further analysis
of transcriptional responses implicated 18 transcription factors in
regulating responses to smoke treatment, and identified gene sets
regulated by each transcription factor, including pathways for oxidative
stress, DNA damage/repair, ER stress, apoptosis, and cell cycle arrest.
Assays for 42 cytokines in HUVEC cells and iECs identified 23 cytokines
that responded dynamically to cigarette smoke. These cytokines and
cellular stress response pathways describe endothelial responses for
lymphocyte attachment, activation of coagulation and complement, lymphocyte
growth factors, and inflammation and fibrosis; EC-initiated events
that collectively lead to atherosclerosis. Thus, these studies validate
the iEC model and identify transcriptional response networks by which
ECs respond to tobacco smoke. Our results systematically trace how
ECs use these response networks to regulate genes and pathways, and
finally cytokine signals to other cells, to initiate the diverse processes
that lead to atherosclerosis and cardiovascular disease.