Canonical Wnt Signaling Promotes Early Hematopoietic Progenitor Formation and Erythroid Specification during Embryonic Stem Cell Differentiation

Abstract

The generation of hematopoietic stem cells (HSCs) during development is a complex process linked to morphogenic signals. Understanding this process is important for regenerative medicine applications that require in vitro production of HSC. In this study we investigated the effects of canonical Wnt/β-catenin signaling during early embryonic differentiation and hematopoietic specification using an embryonic stem cell system. Our data clearly demonstrates that following early differentiation induction, canonical Wnt signaling induces a strong mesodermal program whilst maintaining a degree of stemness potential. This involved a complex interplay between β-catenin/TCF/LEF/Brachyury/Nanog. β-catenin mediated up-regulation of TCF/LEF resulted in enhanced brachyury levels, which in-turn lead to Nanog up-regulation. During differentiation, active canonical Wnt signaling also up-regulated key transcription factors and cell specific markers essential for hematopoietic specification, in particular genes involved in establishing primitive erythropoiesis. This led to a significant increase in primitive erythroid colony formation. β-catenin signaling also augmented early hematopoietic and multipotent progenitor (MPP) formation. Following culture in a MPP specific cytokine cocktail, activation of β-catenin suppressed differentiation of the early hematopoietic progenitor population, with cells displaying a higher replating capacity and a propensity to form megakaryocytic erythroid progenitors. This bias towards erythroid lineage commitment was also observed when hematopoietic progenitors were directed to undergo myeloid colony formation. Overall this study underscores the importance of canonical Wnt/β-catenin signaling in mesodermal specification, primitive erythropoiesis and early hematopietic progenitor formation during hematopoietic induction.

Impaired Proliferative Potential of Bone Marrow Mesenchymal Stromal Cells in Patients with Myelodysplastic Syndromes Is Associated with Abnormal WNT Signaling Pathway

“…The underlying mechanism to account for this defect has not been elucidated thus far. Nevertheless, it has recently been reported that pharmacological activation of the canonical WNT signaling by the GSK-3b inhibitor LiCl primes undifferentiated MSCs toward osteoblastic lineage [32]. In view of this observation and provided that in MDS-derived MSCs the canonical WNT signaling is downregulated, we hypothesized that the reduced osteoblastic lineage priming of patient MDSs might be attributed, at least in part, to the impaired canonical WNT signaling.…”

“…Activation of canonical WNT signaling by the GSG-3b inhibitor LiCl has been shown to prime undifferentiated MSCs toward the osteoblastic lineage [32]. In view of this observation and provided that in MDS-derived MSCs the canonical WNT signaling is downregulated, we investigated whether the reduced osteoblastic lineage priming of MDSderived MSCs might be attributed, at least in part, to the impaired canonical WNT signaling.…”

Expression of (Pro)renin Receptor During Rapamycin-Induced Erythropoiesis in K562 Erythroleukemia Cells and Its Possible Dual Actions on Erythropoiesis

“…(P)RR and v-ATPase were shown to be required to mediate Wnt signaling during antero-posterior patterning of Xenopus early central nervous system development. There has been accumulating evidence which shows the close relationship among iron, the Wnt signaling and erythropoiesis (Brookes et al 2008;Tarafdar et al 2013). Canonical Wnt/β-catenin signaling plays important roles in mesodermal specification, primitive erythropoiesis and early hematopoietic progenitor formation during hematopoietic induction (Tarafdar et al 2013).…”

“…There has been accumulating evidence which shows the close relationship among iron, the Wnt signaling and erythropoiesis (Brookes et al 2008;Tarafdar et al 2013). Canonical Wnt/β-catenin signaling plays important roles in mesodermal specification, primitive erythropoiesis and early hematopoietic progenitor formation during hematopoietic induction (Tarafdar et al 2013). Brookes et al (2008) speculated that iron-medicated Wnt signaling and c-myc induced expression of transferrin receptor 1.…”

“…Protein was quantified by Bradford protein assay (Bio-rad, Hercules, CA, USA). Cell lysates were electrophoresed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and then transferred to a polyvinylidene difluoride (PVDF) membrane (Millipore Corporation, Billerica, MA, USA), as previously described (Udono-Fujimori et al 2004;Kaneko et al 2012).…”