Continuous Antagonism by Dkk1 Counter Activates Canonical Wnt Signaling and Promotes Cardiomyocyte Differentiation of Embryonic Stem Cells

Human embryonic stem cells (hESCs) provide an important means to effectively study soluble and cell-bound mediators that regulate development of early blood and endothelial cells in a human model system. Here, several complementary methods are used to demonstrate canonical Wnt signaling is important for development of hESC-derived cells with both hematopoietic and endothelial potential. Analyses using both standard flow cy-tometry, as well the more detailed high-throughput image scanning flow cytometry, characterizes sequential development of distinct early developing CD34brightCD31+Flk1+ cells and a later population of CD34dimCD45+ cells. While the CD34brightCD31+Flk1+ have a more complex morphology and can develop into both endothelial cells and hematopoietic cells, the CD34dimCD45+ cells have a simpler morphology and give rise to only hematopoietic cells. Treatment with dickkopf1 to inhibit Wnt signaling results in a dramatic decrease in development of cells with hematoendothelial potential. In addition, activation of the canonical Wnt signaling pathway in hESCs by coculture with stromal cells that express Wnt1, but not use of noncanonical Wnt5-expressing stromal cells, results in an accelerated differentiation and higher percentage of CD34brightCD31+Flk1+ cells at earlier stages of differentiation. These studies effectively demonstrate the importance of canonical Wnt signaling to mediate development of early hematoendothelial progenitors during human development.

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Canonical Wnt Signaling Induces a Primitive Endoderm Metastable State in Mouse Embryonic Stem Cells

Stem Cells ◽

10.1002/stem.1321 ◽

2013 ◽

Vol 31 (4) ◽

pp. 752-764 ◽

Cited By ~ 25

Author(s):

Feodor D. Price ◽

Hang Yin ◽

Andrew Jones ◽

Wilfred van Ijcken ◽

Frank Grosveld ◽

...

Keyword(s):

Stem Cells ◽

Embryonic Stem Cells ◽

Wnt Signaling ◽

Metastable State ◽

Embryonic Stem ◽

Mouse Embryonic Stem Cells ◽

Primitive Endoderm ◽

Canonical Wnt Signaling ◽

Canonical Wnt

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Retinoic Acid Suppresses the Canonical Wnt Signaling Pathway in Embryonic Stem Cells and Activates the Noncanonical Wnt Signaling Pathway

Stem Cells ◽

10.1002/stem.1706 ◽

2014 ◽

Vol 32 (8) ◽

pp. 2061-2071 ◽

Cited By ~ 30

Author(s):

Kwame Osei-Sarfo ◽

Lorraine J. Gudas

Keyword(s):

Stem Cells ◽

Retinoic Acid ◽

Embryonic Stem Cells ◽

Wnt Signaling ◽

Signaling Pathway ◽

Wnt Signaling Pathway ◽

Embryonic Stem ◽

Canonical Wnt Signaling ◽

Canonical Wnt

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Abstract 1457: IGFBP-4-Mediated Wnt Inhibition is Required for Cardiac Myogenesis

Circulation ◽

10.1161/circ.118.suppl_18.s_329-a ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Weidong Zhu ◽

Ichiro Shiojima ◽

Li Zhi ◽

Hiroyuki Ikeda ◽

Masashi Yoshida ◽

...

Keyword(s):

Growth Factor ◽

Wnt Signaling ◽

Heart Diseases ◽

Es Cells ◽

Embryonic Stem ◽

Cardiomyocyte Differentiation ◽

Canonical Wnt Signaling ◽

Canonical Wnt

Insulin-like growth factor-binding proteins (IGFBPs) bind to and modulate the actions of insulin-like growth factors (IGFs). Although some of the effects of IGFBPs appear to be independent of IGFs, the precise mechanisms of IGF-independent actions of IGFBPs are largely unknown. In this study we demonstrate that IGFBP-4 is a novel cardiogenic growth factor. IGFBP-4 enhanced cardiomyocyte differentiation of P19CL6 embryonal carcinoma cells and embryonic stem (ES) cells in vitro. Conversely, siRNA-mediated knockdown of IGFBP-4 in P19CL6 cells or ES cells attenuated cardiomyocyte differentiation, and morpholino-mediated knockdown of IGFBP-4 in Xenopus embryos resulted in severe cardiac defects and complete absence of the heart in extreme cases. We also demonstrate that the cardiogenic effect of IGFBP-4 was independent of its IGF-binding activity but was mediated by the inhibitory effect on canonical Wnt signaling. IGFBP-4 physically interacted with a Wnt receptor Frizzled 8 (Frz8) and a Wnt co-receptor low-density lipoprotein receptor-related protein 6 (LRP6), and inhibited the binding of Wnt3A to Frz8 and LRP6. Moreover, the cardiogenic defects induced by IGFBP-4 knockdown both in vitro and in vivo was rescued by simultaneous inhibition of canonical Wnt signaling. Thus, IGFBP-4 is an inhibitor of the canonical Wnt signaling, and Wnt inhibition by IGFBP-4 is required for cardiogenesis. The present study provides a molecular link between IGF signaling and Wnt signaling, and suggests that IGFBP-4 may be a novel therapeutic target for heart diseases.

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Importance of WNT-dependent signaling for derivation and maintenance of primed pluripotent bovine embryonic stem cells

Biology of Reproduction ◽

10.1093/biolre/ioab075 ◽

2021 ◽

Author(s):

Yao Xiao ◽

Thiago F Amaral ◽

Pablo J Ross ◽

Delia A Soto ◽

Kenneth E Diffenderfer ◽

...

Keyword(s):

Stem Cells ◽

Embryonic Stem Cells ◽

Wnt Signaling ◽

Embryonic Stem ◽

Janus Kinase ◽

Inhibitory Protein ◽

Stat3 Phosphorylation ◽

Series Of Experiments ◽

Canonical Wnt

Abstract The WNT signaling system plays an important but paradoxical role in regulation of pluripotency. In the cow, IWR-1, which inhibits canonical WNT activation and has WNT-independent actions, promotes derivation of primed pluripotent embryonic stem cells (ESC) from the blastocyst. Here we describe a series of experiments to determine whether derivation of ESC could be generated by replacing IWR-1 with other inhibitors of WNT signaling. Results confirm the importance of inhibition of canonical WNT signaling for establishment of pluripotent ESC in cattle and indicate that actions of IWR-1 can be mimicked by the WNT secretion inhibitor IWP2 but not by the tankyrase inhibitor XAV939 or WNT inhibitory protein dickopf 1. The role of janus kinase (JAK)-mediated signaling pathways for maintenance of pluripotency of ESC was also evaluated. Maintenance of pluripotency of ESC lines was blocked by a broad inhibitor of JAK even though cells did not express phosphorylated signal transducer and activator of transcription 3 (STAT3). Further studies with blastocysts indicated IWR-1 blocks activation of STAT3 phosphorylation. A likely explanation is that IWR-1 blocks differentiation of ESC into a pSTAT3+ lineage. In conclusion, results presented here indicated the importance of inhibition of WNT signaling for derivation of pluripotent bovine ESC (bESC), the role of JAK signaling for maintenance of pluripotency and the participation of IWR-1 in inhibition of activation of STAT3.

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