Pluripotent stem cell-derived epithelium misidentified as brain microvascular endothelium requires ETS factors to acquire vascular fate

Proc Natl Acad Sci U S A. 2021 Feb 23;118(8):e2016950118. doi: 10.1073/pnas.2016950118.


Cells derived from pluripotent sources in vitro must resemble those found in vivo as closely as possible at both transcriptional and functional levels in order to be a useful tool for studying diseases and developing therapeutics. Recently, differentiation of human pluripotent stem cells (hPSCs) into brain microvascular endothelial cells (ECs) with blood-brain barrier (BBB)-like properties has been reported. These cells have since been used as a robust in vitro BBB model for drug delivery and mechanistic understanding of neurological diseases. However, the precise cellular identity of these induced brain microvascular endothelial cells (iBMECs) has not been well described. Employing a comprehensive transcriptomic metaanalysis of previously published hPSC-derived cells validated by physiological assays, we demonstrate that iBMECs lack functional attributes of ECs since they are deficient in vascular lineage genes while expressing clusters of genes related to the neuroectodermal epithelial lineage (Epi-iBMEC). Overexpression of key endothelial ETS transcription factors (ETV2, ERG, and FLI1) reprograms Epi-iBMECs into authentic endothelial cells that are congruent with bona fide endothelium at both transcriptomic as well as some functional levels. This approach could eventually be used to develop a robust human BBB model in vitro that resembles the human brain EC in vivo for functional studies and drug discovery.

Keywords: blood–brain barrier; cellular identity; endothelial cells; induced pluripotent; single-cell RNA sequencing.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood-Brain Barrier
  • Brain / blood supply
  • Brain / cytology
  • Cell Differentiation
  • Cell Line
  • Cellular Reprogramming / physiology
  • Endothelium, Vascular / cytology*
  • Endothelium, Vascular / physiology
  • Gene Expression
  • Humans
  • Mice, Inbred Strains
  • Pluripotent Stem Cells / cytology*
  • Pluripotent Stem Cells / physiology
  • Proto-Oncogene Protein c-fli-1 / genetics
  • Proto-Oncogene Protein c-fli-1 / metabolism
  • Single-Cell Analysis
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Transcriptional Regulator ERG / genetics
  • Transcriptional Regulator ERG / metabolism


  • ERG protein, human
  • ETV2 protein, human
  • FLI1 protein, human
  • Proto-Oncogene Protein c-fli-1
  • Transcription Factors
  • Transcriptional Regulator ERG