Inhibiting Smad2/3 signaling in pluripotent mouse embryonic stem cells enhances endoderm formation by increasing transcriptional priming of lineage‐specifying target genes

Abstract

Background Pluripotent embryonic stem cells (ESCs) offer great potential for regenerative medicine. However, efficient in vitro generation of specific desired cell types is still a challenge. We previously established that Smad2/3 signaling, essential for endoderm formation, regulates target gene expression by counteracting epigenetic repression mediated by Polycomb Repressive Complex 2 (PRC2). Although this mechanism has been demonstrated during differentiation and reprogramming, little is known of its role in pluripotent cells. Results Chromatin immunoprecipitation-deep sequencing of undifferentiated mouse ESCs inhibited for Smad2/3 signaling identified Prdm14, important for protecting pluripotency, as a target gene. Although Prdm14 accumulates the normally repressive PRC2 deposited histone modification H3K27me3 under these conditions, surprisingly expression increases. Analysis indicates that increased H3K27me3 leads to increased binding of PRC2 accessory component Jarid2 and recruitment of RNA polymerase II. Similar increases were found at the Nodal endoderm target gene Eomesodermin, but it remained unexpressed in pluripotent cells as normal. Upon differentiation, however, Eomesodermin expression was significantly higher than in cells that had not been inhibited for signaling prior to differentiation. In addition, endoderm formation was markedly increased. Conclusions Blocking Smad2/3 signaling in pluripotent stem cells results in epigenetic changes that enhance the capacity for endoderm differentiation.

Mapping a Circular RNA–microRNA–mRNA-Signaling Regulatory Axis that Modulates Stemness Properties of Cancer Stem Cell Populations in Colorectal Cancer Spheroid Cells

“…The six core mRNAs have, indeed, also previously been reported to be involved in diverse CSC-related properties, ranging from proliferation, migration and invasion, chemoresistance and tumorigenicity (see Table 4 for full references). Importantly, pluripotency-associated properties have also been demonstrated in other reports [69][70][71][72][73]. The six core mRNAs may further be implicated to be linked with four major signaling pathways that modulate numerous CSC-associated properties observed in the CRC spheroids ( Figure 6).…”

Network analysis of microRNAs, transcription factors, and target genes involved in axon regeneration

“…SMAD transcription modulators regulate multiple cellular processes (Dahle and Kuehn, 2016). SMADs are divided into three classes: receptorregulated Smads (SMAD1, SMAD2, SMAD3, SMAD5, and SMAD8/9), the common-mediator Smad (SMAD4), and inhibitory Smads (SMAD6 and SMAD7).…”