AML Survival and In Vivo Progression Is Dependent On β-Catenin Signaling.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2398-2398
Author(s):  
Elena K Siapati ◽  
Magda Papadaki ◽  
Zoi Kozaou ◽  
Erasmia Rouka ◽  
Evridiki Michali ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Wnt Signaling Pathway ◽  
Canonical Wnt Signaling ◽  
Down Regulation ◽  
Canonical Wnt

Abstract Abstract 2398 Poster Board II-375 B-catenin is the central effector molecule of the canonical wnt signaling pathway which governs cell fate and differentiation during embryogenesis as well as self-renewal of hematopoietic stem cells. Deregulation of the pathway has been observed in various malignancies including myeloid leukemias where over-expression of β-catenin is an independent adverse prognostic factor. In the present study we examined the functional outcome of stable β-catenin down-regulation through lentivirus-mediated expression of short hairpin RNA (shRNA). Reduction of the β-catenin levels in AML cell lines and patient samples diminished their in vitro proliferation ability without significantly affecting cell viability. In order to study the role of β-catenin in vivo, we transplanted leukemic cell lines with control or reduced levels of β-catenin in NOD/SCID animals and analyzed the engraftment levels in the bone marrow. We observed that while the immediate homing of the cells was not affected by the β-catenin levels, the bone marrow engraftment was directly dependent on its levels. Subsequent examination of bone marrow sections revealed that the reduced engraftment was partly due to the inability of the cells with lower β-catenin levels to dock to the endosteal niches, a finding that was confirmed in competitive repopulation assays with untransduced cells. When we examined the expression levels of adhesion molecules and integrins in engrafted cells in vivo, we observed a significant down-regulation of CD44 expression, a molecule that participates in the interaction of HSCs with the niche. Gene expression analysis of the components of the wnt signaling pathway showed that the pathway is subject to tight transcriptional regulation with minor expression deviations. We did, however, observe an up-regulation in components that participate in the non-canonical wnt signaling pathways such as the WNT5B ligand. Ongoing experiments in normal cord blood CD34+ cells will determine the in vivo role of β-catenin signaling in normal hematopoietic progenitors. In conclusion, our study showed that β-catenin comprises an integral part in the development and progression of AML in vivo, indicating that manipulation of the wnt pathway may hold a therapeutic potential in the management of AML. Disclosures: No relevant conflicts of interest to declare.

The role of magnesium ions in bone regeneration involves the canonical Wnt signaling pathway

2019 ◽  
Vol 98 ◽  
pp. 246-255 ◽  
Author(s):  
Chu-Chih Hung ◽  
Amy Chaya ◽  
Kai Liu ◽  
Konstantinos Verdelis ◽  
Charles Sfeir
Keyword(s):  
Wnt Signaling ◽  
Bone Regeneration ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Magnesium Ions ◽  
Canonical Wnt Signaling ◽  
Canonical Wnt

scholarly journals MULTIFACTORIAL PATHOGENESIS OF OSTEOPOROSIS AND THE ROLE OF GENES OF CANONICAL WNT-SIGNALING PATHWAY

2015 ◽  
Vol 18 (2) ◽  
pp. 15-19
Author(s):  
E A Mailyan
Keyword(s):  
Genetic Analysis ◽  
Wnt Signaling ◽  
Candidate Genes ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Scientific Research ◽  
Canonical Wnt Signaling ◽  
Canonical Wnt ◽  
Skeleton Formation

Nowadays, multifactorial nature of osteoporosis does not raise any doubts. Besides, it should be noted that about 90% disease cases are determined genetically. In 1990-s a number of candidate genes mutations were established which increase the risk of osteoporosis development. VDR, ESR1, ESR2, COLIA1, PTH, CT, CTR, BGP, AR, GCCR, TGFB1, IL-6, IGF1, IL-1ra, OPG were considered to be this kind of genes. New genetic analysis technologies (GWAS, etc.) gave the opportunity to expand our conception about multi genomic pathogenesis of osteoporosis and to point out a new group of genes candidate - a canonical Wnt-signaling pathway genes (CTNNB1, SOST, FOXC2, FOXL1, LRP4, LRP5, WNT1, WNT3, WNT16, DKK1, AXIN1, JAG1, etc.). Extreme importance of canonical Wnt-signaling pathway and genes given above in skeleton formation and its strength necessitate the need for further scientific research and opens perspective to improve osteoporosis diagnostics, treatment and prognosis.

Normal hematopoiesis and hematologic malignancies: Role of canonical Wnt signaling pathway and stromal microenvironment

2013 ◽  
Vol 1835 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Paul Faustin Seke Etet ◽  
Lorella Vecchio ◽  
Patrice Bogne Kamga ◽  
Elias Nchiwan Nukenine ◽  
Mauro Krampera ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Hematologic Malignancies ◽  
Canonical Wnt Signaling ◽  
Stromal Microenvironment ◽  
Canonical Wnt

scholarly journals Wnt-inducible Lrp6-APEX2 Interacting Proteins Identify ESCRT Machinery and Trk-Fused Gene as Components of the Wnt Signaling Pathway

2020 ◽  
Author(s):  
Gabriele Colozza ◽  
Yasaman Jami-Alahmadi ◽  
Alyssa Dsouza ◽  
Nydia Tejeda-Muñoz ◽  
Lauren V. Albrecht ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Secretory Pathway ◽  
Wnt Signaling Pathway ◽  
Canonical Wnt Signaling ◽  
Labeling Approach ◽  
Canonical Wnt ◽  
Fused Gene ◽  
Multivesicular Endosomes

AbstractThe canonical Wnt signaling pathway serves as a hub connecting diverse cellular physiological processes, such as β-catenin signaling, differentiation, growth, protein stability, macropinocytosis, and nutrient acquisition in lysosomes. We have proposed that sequestration of β-catenin destruction complex components in multivesicular bodies (MVBs) is required for sustained canonical Wnt signaling. In this study, we investigated the events that follow activation of the canonical Wnt receptor Lrp6 using an APEX2-mediated proximity labeling approach. The Wnt co-receptor Lrp6 was fused to APEX2 and used to biotinylate targets that are recruited near the receptor during Wnt signaling at different time periods. Lrp6 proximity targets were identified by mass spectrometry, and revealed that many components of the ESCRT (Endocytic Sorting Components Required for Transport) machinery interacted with Lrp6 within 5 minutes of Wnt3a treatment. This supports the proposal of a central role of multivesicular endosomes in canonical Wnt signaling. Interestingly, proteomic analyses identified the Trk-fused gene (TFG), previously known to regulate the cell secretory pathway and to be rearranged in thyroid and lung cancers, as being strongly enriched in the proximity of Lrp6. We provide evidence that TFG specifically co-localized with MVBs after Wnt stimulation. TFG depletion with siRNA, or knock-out with CRISPR/Cas9, significantly reduced Wnt/β-catenin signaling in cell culture. In vivo, studies in the Xenopus system showed that TFG is required for endogenous Wnt-dependent embryonic patterning. The results suggest that the multivesicular endosomal machinery and the novel player TFG have important roles in Wnt signaling.SignificanceWnt/β-catenin signaling is a conserved pathway involved in cell differentiation and in the regulation of many other processes, including cell growth and proliferation, macropinocytosis, and cell metabolism. Endocytosis is required to regulate Wnt signaling, but the precise factors at play are still elusive. Here, we describe a biotin-dependent proximity labeling approach using ascorbate peroxidase-tagged Lrp6, a Wnt co-receptor. Proteomic analysis of biotinylated-enriched targets identified numerous multivesicular endosome proteins that were recruited to the receptor shortly after addition of Wnt protein. Additionally, we identified the protein TFG as one of the strongest interactors with Lrp6. TFG co-localized with Wnt-induced multivesicular endosomes. Xenopus embryo assays revealed that TFG is required in vivo for canonical Wnt signaling.

Polycomb Repressive Complex 1 Enhances HSC Self-Renewal through Repressing the Canonical Wnt Signaling Pathway

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2378-2378
Author(s):  
Sisi Chen ◽  
Xicheng Liu ◽  
Rui Gao ◽  
Michihiro Kobayashi ◽  
Hao Yu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Canonical Wnt Signaling ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Canonical Wnt

Abstract Polycomb group (PcG) proteins are epigenetic gene silencers that have been implicated in stem cell maintenance and cancer development. Genetic and biochemical studies indicate that Polycomb group proteins exist in at least two protein complexes, Polycomb repressive complex 2 (PRC2) and Polycomb repressive complex 1 (PRC1), that act in concert to initiate and maintain stable gene repression. While studies on individual PRC1 component suggest that PRC1 plays an important role in hematopoiesis, how PRC1 regulates transcriptional repression in hematopoietic stem cells (HSCs) is largely unknown. Bmi1 and Mel18 are two major homologs of the PCGF subunit within the PRC1 complex. Bmi1 is a positive regulator of HSC self-renewal; however, the role of Mel18 in hematopoiesis has been controversial. To determine whether Bmi1 and Mel18 play redundant or distinct role in HSC self-renewal, we have generated Bmi1 and Mel18 conditional knockout mice. While acute deletion of Mel18 affects neither HSC frequency nor lineage commitment, we found that Mel18-deficent hematopoietic progenitor cells showed enhanced replating potential compared to wild type cells. To determine the role of Mel18 in HSC self-renewal, we performed serial HSC transplantation assays and found that the repopulating ability of Mel18-/- HSCs was significantly higher than WT HSCs in both primary and secondary transplantation assays, demonstrating that the loss of Mel18 enhances HSC self-renewal in vivo. We hypothesize that loss of Bmi1 and Mel18 in hematopoietic stem cells will disrupt PRC1 complex and impairs HSC self-renewal. To determine the role of PRC1 complex in HSCs, we analyzed the HSC behavior in Bmi1 and Mel18 double-deficient mice. While we found that Bmi1-deficient HSCs showed decreased repopulating potential compared to WT HSCs 16 weeks following transplantation, loss of both Bmi1 and Mel18 in HSCs resulted in even more severe self-renewal defects. In addition, loss of both Bmi1 and Mel18 resulted in decreased myeloid differentiation and increased B cell differentiation compared to WT, Mel18 KO, and Bmi1 KO mice. These data demonstrate that Bmi1 and Mel18 have non-overlapping role in HSC maintenance and lineage commitment. Given that Bmi1 plays a dominant role in the PRC1 complex, we decided to identify Bmi1 target genes in hematopoietic stem cells to understand how PRC1 complex regulates HSC self-renewal. We performed transcript profiling assays to compare gene expression in HSCs isolated from wild type and Bmi1-/- mice. The Ingenuity Pathways indicates that the canonical Wnt signaling is significantly elevated in Bmi1 null HSCs compared to WT HSCs. We confirmed the upregulation of several genes of the Wnt pathway in Bmi1 null HSCs by quantitative real-time PCR analysis. To determine whether Bmi1 can repress the activation of Wnt signaling in cells, we utilized the Top-Flash Wnt reporter system. Stimulation of 293T cells with Wnt3a activates the Wnt reporter and this activation can be efficiently repressed by Bmi1. Furthermore, we detected the association of Bmi1 with the Lef1, Tcf4, and Axin2 promoters in Baf3 cells by ChIP experiment. Thus, Bmi1 directly represses the expression of several Wnt genes in hematopoietic cells. To determine the functional significance of activation of Wnt signaling in Bmi1 null HSCs, we have generated R26StopFL Bmi1-Apcf/f-Mx1-Cre+ and Bmi1f/f-Ctnnb1f/f-Mx1-Cre+ mice. Loss of Apc in hematopoietic cells activates the Wnt signaling pathway and impairs HSC self-renewal. We found that expressing three-copies of Bmi1 from the Rosa26 locus enhanced the self-renewal capabilities of Apc deficient HSCs in transplantation assays. Ctnnb1 encodes b-catenin and loss of Ctnnb1 in HSCs diminishes Wnt signaling. Acute deletion of Bmi1 in hematopoietic compartments resulted in decreased bone marrow cellularity and enhanced apoptosis of hematopoietic stem and progenitor cells. Deletion of Ctnnb1 in Bmi1 null hematopoietic cells rescued these defects. Thus, impaired HSC self-renewal seen in Bmi1 null mice is, at least in part, due to activation of the canonical Wnt signaling pathway. Taken together, we demonstrate that PRC1 complex enhances HSC self-renewal through inhibiting the canonical Wnt signaling. Disclosures No relevant conflicts of interest to declare.

scholarly journals Icariin Regulates the Bidirectional Differentiation of Bone Marrow Mesenchymal Stem Cells through Canonical Wnt Signaling Pathway

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Jun-ming Huang ◽  
Yuan Bao ◽  
Wei Xiang ◽  
Xing-zhi Jing ◽  
Jia-chao Guo ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Western Blot ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Canonical Wnt Signaling ◽  
Marrow Mesenchymal Stem Cells ◽  
Canonical Wnt

Fat infiltration within the bone marrow is easily observed in some postmenopausal women. Those fats are mainly derived from bone marrow mesenchymal stem cells (BMMSCs). The increment of adipocytes derived from BMMSCs leads to decreased osteoblasts derived from BMMSCs, so the bidirectional differentiation of BMMSCs significantly contributes to osteoporosis. Icariin is the main extractive of Herba Epimedii which is widely used in traditional Chinese medicine. In this experiment, we investigated the effect of icariin on the bidirectional differentiation of BMMSCs through quantitative real-time PCR, immunofluorescence, western blot, and tissue sections in vitro and in vivo. We found that icariin obviously promotes osteogenesis and inhibits adipogenesis through detecting staining and gene expression. Micro-CT analysis showed that icariin treatment alleviated the loss of cancellous bone of the distal femur in ovariectomized (OVX) mice. H&E staining analysis showed that icariin-treated OVX mice obtained higher bone mass and fewer bone marrow lipid droplets than OVX mice. Western blot and immunofluorescence showed that icariin regulates the bidirectional differentiation of BMMSCs via canonical Wnt signaling. This study demonstrates that icariin exerts its antiosteoporotic effect by regulating the bidirectional differentiation of BMMSCs through the canonical Wnt signaling pathway.

scholarly journals Stiffness of Nanoparticulate Mineralized Collagen Scaffolds Triggers Osteogenesis via Mechanotransduction and Canonical Wnt Signaling

2020 ◽  
Author(s):  
Qi Zhou ◽  
Shengyu Lyu ◽  
Anthony A. Bertrand ◽  
Allison C. Hu ◽  
Candace H. Chan ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Progenitor Cell ◽  
Ex Vivo ◽  
Wnt Signaling Pathway ◽  
Binding Motif ◽  
Canonical Wnt Signaling ◽  
Canonical Wnt ◽  
Mineralized Collagen

AbstractThe ability of the extracellular matrix (ECM) to instruct progenitor cell differentiation has generated excitement for the development of materials-based regenerative solutions. We previously described a nanoparticulate mineralized collagen glycosaminoglycan (MC-GAG) material capable of inducing in vivo skull regeneration approaching 60% of the biomechanical properties of native calvarium without exogenous growth factors or ex vivo progenitor cell-priming, suggesting promise as a first-generation material for skull regeneration. Here, we evaluated the contribution of titrating stiffness to osteogenicity by comparing non-crosslinked (NX-MC) and crosslinked (MC) forms of MC-GAG. While both materials were osteogenic, MC demonstrated an increased expression of osteogenic markers and mineralization compared to NX-MC. Both materials were capable of autogenously activating the canonical bone morphogenetic protein receptor (BMPR) signaling pathway with phosphorylation of Smad1/5 (small mothers against decapentaplegic-1/5). However, unlike NX-MC, hMSCs cultured on MC demonstrated significant elevations in the major mechanotransduction mediators YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif) expression coincident with β-catenin activation in the canonical Wnt signaling pathway. Inhibition of YAP/TAZ activation reduced osteogenic marker expression, mineralization, and β-catenin activation in MC with a much lesser of an effect on NX-MC. YAP/TAZ inhibition also resulted in a reciprocal increase in Smad1/5 phosphorylation as well as BMP2 expression. Our results indicate that increasing MC-GAG stiffness induces osteogenic differentiation via the mechanotransduction mediators YAP/TAZ and the canonical Wnt signaling pathway, whereas the canonical BMPR signaling pathway is activated in a manner independent of mechanical cues.

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