A model of early human embryonic stem cell differentiation reveals inter- and intracellular changes on transition to squamous epithelium

Vasiliy Galat*, Sergey Malchenko, Yekaterina Galat, Alex Ishkin, Yuri Nikolsky, Steven T. Kosak, Bento Marcelo Soares, Philip Iannaccone, John D. Crispino, Mary J.C. Hendrix

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The molecular events leading to human embryonic stem cell (hESC) differentiation are the subject of considerable scrutiny. Here, we characterize an in vitro model that permits analysis of the earliest steps in the transition of hESC colonies to squamous epithelium on basic fibroblast growth factor withdrawal. A set of markers (GSC, CK18, Gata4, Eomes, and Sox17) point to a mesendodermal nature of the epithelial cells with subsequent commitment to definitive endoderm (Sox17, Cdx2, nestin, and Islet1). We assayed alterations in the transcriptome in parallel with the distribution of immunohistochemical markers. Our results indicate that the alterations of tight junctions in pluripotent culture precede the beginning of differentiation. We defined this cell population as "specified," as it is committed toward differentiation. The transitional zone between "specified" pluripotent and differentiated cells displays significant up-regulation of keratin-18 (CK18) along with a decrease in the functional activity of gap junctions and the down-regulation of 2 gap junction proteins, connexin 43 (Cx43) and connexin 45 (Cx45), which is coincidental with substantial elevation of intracellular Ca2+ levels. These findings reveal a set of cellular changes that may represent the earliest markers of in vitro hESC transition to an epithelial phenotype, before the induction of gene expression networks that guide hESC differentiation. Moreover, we hypothesize that these events may be common during the primary steps of hESC commitment to functionally varied epithelial tissue derivatives of different embryological origins.

Original languageEnglish (US)
Pages (from-to)1250-1263
Number of pages14
JournalStem Cells and Development
Volume21
Issue number8
DOIs
StatePublished - May 20 2012

ASJC Scopus subject areas

  • Hematology
  • Cell Biology
  • Developmental Biology

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