scholarly journals Investigating the mechanistic basis of biomechanical input controlling skeletal development: exploring the interplay with Wnt signalling at the joint

2018 ◽  
Vol 373 (1759) ◽  
pp. 20170329 ◽  
Author(s):  
Rebecca A. Rolfe ◽  
Claire A. Shea ◽  
Pratik Narendra Pratap Singh ◽  
Amitabha Bandyopadhyay ◽  
Paula Murphy
Keyword(s):  
Mechanical Stimulation ◽  
Wnt Pathway ◽  
Molecular Mechanisms ◽  
Skeletal Development ◽  
Wnt Signalling ◽  
Mechanical Stimuli ◽  
Mechanistic Basis ◽  
Bmp Signalling ◽  
Canonical Wnt ◽  
Mechanical Influence

Embryo movement is essential to the formation of a functional skeleton. Using mouse and chick models, we previously showed that mechanical forces influence gene regulation and tissue patterning, particularly at developing limb joints. However, the molecular mechanisms that underpin the influence of mechanical signals are poorly understood. Wnt signalling is required during skeletal development and is altered under reduced mechanical stimulation. Here, to explore Wnt signalling as a mediator of mechanical input, the expression of Wnt ligand and Fzd receptor genes in the developing skeletal rudiments was profiled. Canonical Wnt activity restricted to the developing joint was shown to be reduced under immobilization, while overexpression of activated β-catenin following electroporation of chick embryo limbs led to joint expansion, supporting the proposed role for Wnt signalling in mechanoresponsive joint patterning. Two key findings advance our understanding of the interplay between Wnt signalling and mechanical stimuli: first, loss of canonical Wnt activity at the joint shows reciprocal, coordinated misregulation of BMP signalling under altered mechanical influence. Second, this occurs simultaneously with increased expression of several Wnt pathway component genes in a territory peripheral to the joint, indicating the importance of mechanical stimulation for a population of potential joint progenitor cells. This article is part of the Theo Murphy meeting issue ‘Mechanics of Development’.

scholarly journals Effect of mechanical loading on insulin-like growth factor-I gene expression in rat tibia

2007 ◽  
Vol 192 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Christianne M A Reijnders ◽  
Nathalie Bravenboer ◽  
Annechien M Tromp ◽  
Marinus A Blankenstein ◽  
Paul Lips
Keyword(s):  
Bone Formation ◽  
Mrna Expression ◽  
Mechanical Loading ◽  
Mechanical Stimulation ◽  
Molecular Mechanisms ◽  
Bone Marrow Cells ◽  
Mechanical Stimuli ◽  
Igf I ◽  
Female Wistar Rats ◽  
Tibia Shaft

Mechanical loading plays an essential role in maintaining skeletal integrity. Mechanical stimulation leads to increased bone formation. However, the cellular and molecular mechanisms that are involved in the translation of mechanical stimuli into bone formation, are not completely understood. Growth factors and osteocytes, which act as mechanosensors, play a key role during the bone formation after mechanical stimulation. The aim of this study was to characterize the role of IGF-I in the translation of mechanical stimuli into bone formation locally in rat tibiae. Fifteen female Wistar rats were randomly assigned to three groups (n = 5): load, sham-loaded, and control. The four-point bending model of Forwood and Turner was used to induce a single period of mechanical loading on the tibia shaft. The effects of mechanical loading on IGF-I mRNA expression were determined with non-radioactive in situ hybridization on decalcified tibiae sections, 6 h after the loading session. Endogenous IGF-I mRNA was expressed in trabecular and cortical osteoblasts, some trabecular and sub-endocortical osteocytes, intracortical endothelial cells of blood vessels, and periosteum. Megakaryocytes, macrophages, and myeloid cells also expressed IGF-I mRNA. In the growth plate, IGF-I mRNA was located in proliferative and hypertrophic chondrocytes. Mechanical loading did not affect the IGF-I mRNA expression in osteoblasts, bone marrow cells, and chondrocytes, but the osteocytes at the endosteal side of the shaft showed a twofold increase of IGF-I mRNA expression. The proportion of IGF-I mRNA positive osteocytes in loaded tibiae was 29.3 ± 12.9% (mean ± s.d.; n = 5), whereas sham-loaded and contra-lateral control tibiae exhibited 16.7 ± 4.4% (n = 5) and 14.7 ± 4.2% (n = 10) respectively (P < 0.05). Lamellar bone formation after a single mechanical loading session was observed at the endosteal side of the shaft. In conclusion, a single loading session results in a twofold up-regulation of IGF-I mRNA synthesis in osteocytes which are present in multiple layers extending into the cortical bone of mechanically stimulated tibia shaft 6 h after loading. This supports the hypothesis that IGF-I, which is located in osteocytes, is involved in the translation of mechanical stimuli into bone formation.

scholarly journals Angiogenesis-Related Functions of Wnt Signaling in Colorectal Carcinogenesis

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3601
Author(s):  
Aldona Kasprzak
Keyword(s):  
Signaling Pathway ◽  
Wnt Pathway ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Biologically Active ◽  
Colorectal Carcinogenesis ◽  
Downstream Signaling ◽  
Vegf Family Members ◽  
Canonical Wnt ◽  
Cell Dissemination

Aberrant activation of the Wnt/Fzd/β-catenin signaling pathway is one of the major molecular mechanisms of colorectal cancer (CRC) development and progression. On the other hand, one of the most common clinical CRC characteristics include high levels of angiogenesis, which is a key event in cancer cell dissemination and distant metastasis. The canonical Wnt/β-catenin downstream signaling regulates the most important pro-angiogenic molecules including vascular endothelial growth factor (VEGF) family members, matrix metalloproteinases (MMPs), and chemokines. Furthermore, mutations of the β-catenin gene associated with nuclear localization of the protein have been mainly detected in microsatellite unstable CRC. Elevated nuclear β-catenin increases the expression of many genes involved in tumor angiogenesis. Factors regulating angiogenesis with the participation of Wnt/β-catenin signaling include different groups of biologically active molecules including Wnt pathway components (e.g., Wnt2, DKK, BCL9 proteins), and non-Wnt pathway factors (e.g., chemoattractant cytokines, enzymatic proteins, and bioactive compounds of plants). Several lines of evidence argue for the use of angiogenesis inhibition in the treatment of CRC. In the context of this paper, components of the Wnt pathway are among the most promising targets for CRC therapy. This review summarizes the current knowledge about the role of the Wnt/Fzd/β-catenin signaling pathway in the process of CRC angiogenesis, aiming to improve the understanding of the mechanisms of metastasis as well as improvements in the management of this cancer.

scholarly journals Wnt5a/FZD4 Mediates the Mechanical Stretch-Induced Osteogenic Differentiation of Bone Mesenchymal Stem Cells

2018 ◽  
Vol 48 (1) ◽  
pp. 215-226 ◽  
Author(s):  
Qingguo Gu ◽  
Haijun Tian ◽  
Kai Zhang ◽  
Deyu Chen ◽  
Dechun Chen ◽  
...  
Keyword(s):  
Bone Formation ◽  
Osteogenic Differentiation ◽  
Mechanical Loading ◽  
Mechanical Stimulation ◽  
Mechanical Stretch ◽  
Wnt Signalling ◽  
Hindlimb Unloading ◽  
Mechanical Stimuli ◽  
Bone Mesenchymal Stem Cells ◽  
Alizarin Red

Background/Aims: Mechanical stimulation and WNT signalling have essential roles in regulating the osteogenic differentiation of bone marrow stromal cells (BMSCs) and bone formation. However, little is known regarding the regulation of WNT signalling molecule expression and therefore the osteogenic differentiation of BMSCs during osteogenesis. Methods: Microarrays of BMSCs from elderly individuals or patients with osteoporosis (GSE35959) from the GEO database were analysed using GeneSight-Lite 4.1.6 (BioDiscovery) and C2 curated gene sets downloaded from Molecular Signatures Database (MSigDB). Realtime PCR and western blotting were used to measure the expression of the indicated genes. ALP and Alizarin red staining were used to evaluate the osteogenesis of BMSCs. Results: In this study, we investigated whether mechanical loading directly regulates the expression of WNT signalling molecules and examined the role of WNT signalling in mechanical loading-triggered osteogenic differentiation and bone formation. We first studied the microarrays of samples from patients with osteoporosis and found downregulation of the GPCR ligand binding gene set in the BMSCs of patients with osteoporosis. Then, we demonstrated that mechanical stimuli can regulate osteogenesis and bone formation both in vivo and in vitro. FZD4 was upregulated during cyclic mechanical stretch (CMS)-induced osteogenic differentiation, and the JNK signalling pathway was activated. FZD4 knockdown inhibited the mechanical stimuli-induced osteogenesis and JNK activity. More importantly, we found an activating effect of WNT5A and FZD4 that regulated bone formation in response to hindlimb unloading in mice, and pretreatment with WNT5A or activation of the expression of FZD4 partly rescued the osteoporosis caused by mechanical unloading. Conclusions: Our results demonstrate, for the first time, that mechanical stimulation alters the expression of genes involved in the osteogenic differentiation of BMSCs via the direct regulation of FZD4 and that therapeutic WNT5A and FZD saRNA may be an efficient strategy for enhancing bone formation under mechanical stimulation.

Molecular Docking Studies to Evaluate Small Molecule Inhibitors of Wnt/Betacatenin Signaling Pathway

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Sankari Dantu Sai Shyama Lakshmi ◽  
Maka Sai Sailaja ◽  
Dalal Swetha ◽  
Chanda Chandrasekhar ◽  
Aluru Ranganadha Reddy
Keyword(s):  
Hydrogen Bond ◽  
Molecular Docking ◽  
Hydrogen Bonds ◽  
Wnt Pathway ◽  
Docking Studies ◽  
Wnt Signalling ◽  
Signalling Pathway ◽  
Wnt Signalling Pathway ◽  
Canonical Wnt Pathway ◽  
Canonical Wnt

Canonical Wnt pathway or β catenin dependent pathway is one of the highly conserved signalling pathway which can control gene expression and regulate cell proliferation, cell adhesion, cell migration, cell polarity and organogenesis. Abnormal regulation of β catenin in the canonical wnt signalling pathway leads to transcription of several genes involved in oncogenic programs. Aberrant signalling of the canonical wnt pathway was observed in several types of cancers including hepatocarcinoma, colorectal cancer and lung cancer. Many small molecules were observed to have the potential to block the aberrant wnt signalling pathway by allosteric binding and inhibiting β catenin molecule. The current study involves screening for ligands which can have strong allosteric binds to β catenin and inhibit wnt signalling pathway. Molecular docking studies were used to evaluate the binding capacity of the selected ligands. Curcumin, Cardamonin, FH535 and ICRT-3 were used as ligands for the molecular docking study with β catenin binding Transcription factor -4 receptor. All chosen ligands have exhibited significant binding energies with the receptor. The highest -9.518272 kcal/mol with Cardamonin followed by -9.28359 kcal/mol with FH535, -8.422604 kcal/mol with curcumin and the least -8.407231 kcal/mol with ICRT-3. All the ligands showed at least 1 hydrogen bond with the target receptor whereas Cardamonin showed 3 hydrogen bonds. Curcumin is a close second forming 2 hydrogen bonds while FH535 and ICRT-3 form only 1 hydrogen bond. The 2D interactions of the ligand and the molecule are visualised by using chimera. We observed Cardamonin to have a very strong binding affinity with the target receptor. Cardamonin can be a suitable drug candidate and might have the potential to inhibit the β catenin dependent wnt signalling pathway.

Influence of PI-3K/Akt Pathway on Wnt Signalling in Myeloid Progenitor Cells. Evidence for a Role of Autocrine/Paracrine Wnt Regulation in CFU-GM Proliferation

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2892-2892
Author(s):  
Georgios Nteliopoulos ◽  
Stephen B Marley ◽  
Myrtle Y Gordon
Keyword(s):  
Conditioned Medium ◽  
Progenitor Cell ◽  
Wnt Pathway ◽  
Wnt Signalling ◽  
Myeloid Progenitor ◽  
Wnt Proteins ◽  
Cd34 Cells ◽  
Myeloid Progenitor Cell ◽  
Progenitor Cell Proliferation ◽  
Canonical Wnt

Abstract We have used a colony replating assay in conjunction with manipulation of the Wnt and PI-3K pathways to investigate regulation of myeloid progenitor cell proliferation/differentiation. We found that PI-3 kinase pathway via Akt acts as a proliferative brake and promotes differentiation in IL3-driven myelopoiesis, since inhibition of PI-3K/Akt pathway with LY294002 (PI-3 kinase inhibitor) and SH-5 (Akt inhibitor) increased proliferation (reduced differentiation). We investigated the involvement of Wnt signalling in CFU-GM proliferation by using exogenous recombinant canonical Wnt3a and non-canonical Wnt5a. We showed that both of the Wnt members cannot support colony growth alone, but when added to IL3 they increased proliferation potential compared with the IL3 control, indicating an involvement of canonical Wnt/β-catenin and non-canonical Wnt pathways in the myeloid progenitor cell proliferation. Immunoblotting analysis indicated that Wnt5a acts independently of β-catenin. Dkk-1 (Wnt-pathway inhibitor) alone did not affect IL-3 dependent proliferation but when combined with recombinant Wnts as expected it abrogated the effects of Wnt3a but not Wnt5a (acts as canonical-Wnt inhibitor). This was confirmed by β-catenin protein levels. Surprisingly, when Dkk-1 was added to LY294002 or SH-5, it blocked their proliferative effects. Dkk-1 acts as functional Wnt-receptor disabler and the finding that it blocks proliferation induced by PI-3K/Akt inhibitors’ indicates a link between the PI-3K and the Wnt signalling pathways. We hypothesised that increased proliferation induced by LY294002 or SH-5 was not mediated by downstream activation of the Wnt pathway but by induced endogenous expression of Wnt proteins and activation of the surface receptor. We conclude that there is a production of endogenous Wnt proteins that increases proliferation. Endogenous Wnt production has been reported in primitive haematopoietic cells so there is potential for a paracrine or autocrine role for these cell regulators. We tested this hypothesis in CD34+ cells and found the addition of SH-5 to IL3 creates an autocrine loop of endogenous Wnt production, which results in the phosphorylation and activation of the LRP6 receptor and the initiation of the canonical signalling pathway. Furthermore, the conditioned medium of cultured CD34+ cells was concentrated by using filtration devices (30kD cut-off) and added to IL3 to support the growth of progenitors of another sample in a CFU-GM assay. We indicated that Wnt production and secretion can act in a paracrine way as well, since IL3+SH-5 conditioned medium increased the proliferative index of CFU-GM cells whereas IL3 conditioned medium did not have significant effect. Dkk-1 abrogated the IL3+SH-5 conditioned medium’s induced proliferation, suggesting that the growth factors that had the proliferative effects were Wnt members. In conclusion, our data suggest that IL3 via PI-3K pathway promotes differentiation of progenitor myeloid cells through inhibition of endogenous Wnt production.

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