Sustained intrinsic WNT and BMP4 activation impairs hESC differentiation to definitive endoderm and drives the cells towards extra-embryonic mesoderm

Abstract

We identified a human embryonic stem cell subline that fails to respond to the differentiation cues needed to obtain endoderm derivatives, differentiating instead into extra-embryonic mesoderm. RNA-sequencing analysis showed that the subline has hyperactivation of the WNT and BMP4 signalling. Modulation of these pathways with small molecules confirmed them as the cause of the differentiation impairment. While activation of WNT and BMP4 in control cells resulted in a loss of endoderm differentiation and induction of extra-embryonic mesoderm markers, inhibition of these pathways in the subline restored its ability to differentiate. Karyotyping and exome sequencing analysis did not identify any changes in the genome that could account for the pathway deregulation. These findings add to the increasing evidence that different responses of stem cell lines to differentiation protocols are based on genetic and epigenetic factors, inherent to the line or acquired during cell culture.

Novel biphasic mechanism of the canonical Wnt signalling component PYGO2 promotes cardiomyocyte differentiation from hUC-MSCs

“…For example, in MaSC/basal cells, PYGO2 represses the chromatin state at the NOTCH3 locus to inhibit its expression (Gu et al 2013 ). NOTCH and canonical Wnt signalling synergistically regulate the expression of BMP4 and SMAD4 to promote normal organ development (Lee et al 2009 ; Markouli et al 2021 ; Szemes et al 2020 ). Here, we detected the expression of the NOTCH signalling pathway component NOTCH3 and the NOTCH target HES1 as well as BMP4 and SMAD4 , which are components of the BMP signalling pathway.…”

Spatial organisation and homeostasis of epithelial lineages at the gastroesophageal junction is regulated by the divergent Wnt mucosal microenvironment

“…Our observation corroborates with other studies describing KRT7 expression in columnar gastric epithelial cells 43 , while its absence does not alter the normal function of epithelial cells or influence other cytokeratin's function 44 . However, increased expression of KRT7 in BE 43 and other cancers 45 might be due to increased BMP4 signals, known to regulate KRT7 expression 46,47 . Thus, we show the existence of two distinct epithelial lineage-specific stem cells that give rise to the squamous epithelium and columnar epithelium, which meet at the GEJ.…”

The isochromosome 20q abnormality of pluripotent cells interrupts germ layer differentiation

“…However, the functional effects of most genetic abnormalities during differentiation remain poorly understood. Reports available point to mixed phenotypes, including reduced, delayed or alternative differentiation capacity in vitro and immature teratomas in vivo ( Ben-David et al., 2014 ; Fazeli et al., 2011 ; Keller et al., 2018 ; Lee et al., 2015 ; Markouli et al., 2019 , 2021 ; Werbowetski-Ogilvie et al., 2009 ). Yet from the studies available, it is becoming evident that the impact of hPSC abnormalities on differentiation is lineage specific and protocol dependent.…”