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Sample records for hypoxia blocks wnt

  1. Hypoxia-inducible factor-2α-dependent hypoxic induction of Wnt10b expression in adipogenic cells.

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    Park, Young-Kwon; Park, Bongju; Lee, Seongyeol; Choi, Kang; Moon, Yunwon; Park, Hyunsung

    2013-09-06

    Adipocyte hyperplasia and hypertrophy in obesity can lead to many changes in adipose tissue, such as hypoxia, metabolic dysregulation, and enhanced secretion of cytokines. In this study, hypoxia increased the expression of Wnt10b in both human and mouse adipogenic cells, but not in hypoxia-inducible factor (HIF)-2α-deficient adipogenic cells. Chromatin immunoprecipitation analysis revealed that HIF-2α, but not HIF-1α, bound to the Wnt10b enhancer region as well as upstream of the Wnt1 gene, which is encoded by an antisense strand of the Wnt10b gene. Hypoxia-conditioned medium (H-CM) induced phosphorylation of lipoprotein-receptor-related protein 6 as well as β-catenin-dependent gene expression in normoxic cells, which suggests that H-CM contains canonical Wnt signals. Furthermore, adipogenesis of both human mesenchymal stem cells and mouse preadipocytes was inhibited by H-CM even under normoxic conditions. These results suggest that O2 concentration gradients influence the formation of Wnt ligand gradients, which are involved in the regulation of pluripotency, cell proliferation, and cell differentiation.

  2. Minocycline blocks glial cell activation and ventilatory acclimatization to hypoxia.

    Science.gov (United States)

    Stokes, Jennifer A; Arbogast, Tara E; Moya, Esteban A; Fu, Zhenxing; Powell, Frank L

    2017-04-01

    Ventilatory acclimatization to hypoxia (VAH) is the time-dependent increase in ventilation, which persists upon return to normoxia and involves plasticity in both central nervous system respiratory centers and peripheral chemoreceptors. We investigated the role of glial cells in VAH in male Sprague-Dawley rats using minocycline, an antibiotic that inhibits microglia activation and has anti-inflammatory properties, and barometric pressure plethysmography to measure ventilation. Rats received either minocycline (45mg/kg ip daily) or saline beginning 1 day before and during 7 days of chronic hypoxia (CH, Pi O 2  = 70 Torr). Minocycline had no effect on normoxic control rats or the hypercapnic ventilatory response in CH rats, but minocycline significantly ( P minocycline administration during only the last 3 days of CH did not reverse VAH. Microglia and astrocyte activation in the nucleus tractus solitarius was quantified from 30 min to 7 days of CH. Microglia showed an active morphology (shorter and fewer branches) after 1 h of hypoxia and returned to the control state (longer filaments and extensive branching) after 4 h of CH. Astrocytes increased glial fibrillary acidic protein antibody immunofluorescent intensity, indicating activation, at both 4 and 24 h of CH. Minocycline had no effect on glia in normoxia but significantly decreased microglia activation at 1 h of CH and astrocyte activation at 24 h of CH. These results support a role for glial cells, providing an early signal for the induction but not maintenance of neural plasticity underlying ventilatory acclimatization to hypoxia. NEW & NOTEWORTHY The signals for neural plasticity in medullary respiratory centers underlying ventilatory acclimatization to chronic hypoxia are unknown. We show that chronic hypoxia activates microglia and subsequently astrocytes. Minocycline, an antibiotic that blocks microglial activation and has anti-inflammatory properties, also blocks astrocyte activation in respiratory

  3. Effect of oxygen on cardiac differentiation in mouse iPS cells: role of hypoxia inducible factor-1 and Wnt/beta-catenin signaling.

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    Tanya L Medley

    Full Text Available BACKGROUND: Disturbances in oxygen levels have been found to impair cardiac organogenesis. It is known that stem cells and differentiating cells may respond variably to hypoxic conditions, whereby hypoxia may enhance stem cell pluripotency, while differentiation of multiple cell types can be restricted or enhanced under hypoxia. Here we examined whether HIF-1alpha modulated Wnt signaling affected differentiation of iPS cells into beating cardiomyocytes. OBJECTIVE: We investigated whether transient and sustained hypoxia affects differentiation of cardiomyocytes derived from murine induced pluripotent stem (iPS cells, assessed the involvement of HIF-1alpha (hypoxia-inducible factor-1alpha and the canonical Wnt pathway in this process. METHODS: Embryoid bodies (EBs derived from iPS cells were differentiated into cardiomyocytes and were exposed either to 24 h normoxia or transient hypoxia followed by a further 13 days of normoxic culture. RESULTS: At 14 days of differentiation, 59 ± 2% of normoxic EBs were beating, whilst transient hypoxia abolished beating at 14 days and EBs appeared immature. Hypoxia induced a significant increase in Brachyury and islet-1 mRNA expression, together with reduced troponin C expression. Collectively, these data suggest that transient and sustained hypoxia inhibits maturation of differentiating cardiomyocytes. Compared to normoxia, hypoxia increased HIF-1alpha, Wnt target and ligand genes in EBs, as well as accumulation of HIF-1alpha and beta-catenin in nuclear protein extracts, suggesting involvement of the Wnt/beta-catenin pathway. CONCLUSION: Hypoxia impairs cardiomyocyte differentiation and activates Wnt signaling in undifferentiated iPS cells. Taken together the study suggests that oxygenation levels play a critical role in cardiomyocyte differentiation and suggest that hypoxia may play a role in early cardiogenesis.

  4. Mesd Is a Universal Inhibitor of Wnt Co-receptor LRP5/6 and Blocks Wnt/β-catenin Signaling in Cancer Cells†

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    Lu, Wenyan; Liu, Chia-Chen; Thottassery, Jaideep V.; Bu, Guojun; Li, Yonghe

    2010-01-01

    Mesd is a specialized chaperone for the low-density lipoprotein receptor-related protein-5 (LRP5) and LRP6. In our previous studies, we found that Mesd binds to mature LRP6 on the cell surface and blocks the binding of Wnt antagonist Dickkopf-1(Dkk1) to LRP6. Herein, we demonstrated that Mesd also binds to LRP5 with a high affinity, and is a universal inhibitor of LRP5/6 ligands. Mesd not only blocks Wnt antagonists Dkk1 and Sclerostin binding to LRP5/6, but also inhibits Wnt3A and Rspondin1-induced Wnt/β-catenin signaling in LRP5/6 expressing cells. We also found that Mesd, Dkk1 and Sclerostin compete with one another for binding to LRP5 and LRP6 at the cell surface. More importantly, we demonstrated that Mesd is able to suppress LRP6 phosphorylation and Wnt/β-catenin signaling in prostate cancer PC-3 cells, and inhibits PC-3 cell proliferation. Our results indicate that recombinant Mesd protein is a useful tool for studying Wnt/β-catenin signaling on the cell surface, and has a potential therapeutic role in Wnt-dependent cancers. PMID:20446724

  5. The Wnt/β-catenin signaling/Id2 cascade mediates the effects of hypoxia on the hierarchy of colorectal-cancer stem cells.

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    Dong, Hye-Jin; Jang, Gyu-Beom; Lee, Hwa-Yong; Park, Se-Ra; Kim, Ji-Young; Nam, Jeong-Seok; Hong, In-Sun

    2016-03-11

    Hypoxia, a feature common to most solid tumors, is known to regulate many aspects of tumorigenesis. Recently, it was suggested that hypoxia increased the size of the cancer stem-cell (CSC) subpopulations and promoted the acquisition of a CSC-like phenotype. However, candidate hypoxia-regulated mediators specifically relevant to the stemness-related functions of colorectal CSCs have not been examined in detail. In the present study, we showed that hypoxia specifically promoted the self-renewal potential of CSCs. Through various in vitro studies, we found that hypoxia-induced Wnt/β-catenin signaling increased the occurrence of CSC-like phenotypes and the level of Id2 expression in colorectal-cancer cells. Importantly, the levels of hypoxia-induced CSC-sphere formation and Id2 expression were successfully attenuated by treatment with a Wnt/β-catenin-signaling inhibitor. We further demonstrated, for the first time, that the degree of hypoxia-induced CSC-sphere formation (CD44(+) subpopulation) in vitro and of tumor metastasis/dissemination in vivo were markedly suppressed by knocking down Id2 expression. Taken together, these data suggested that Wnt/β-catenin signaling mediated the hypoxia-induced self-renewal potential of colorectal-cancer CSCs through reactivating Id2 expression.

  6. Hypoxia-inducible factor-1α and Wnt/β-catenin signaling pathways promote the invasion of hypoxic gastric cancer cells.

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    Liu, Hong-Lan; Liu, Dang; Ding, Guang-Rong; Liao, Peng-Fei; Zhang, Jun-Wen

    2015-09-01

    The present study aimed to examine the association between hypoxia-inducible factor (HIF)-1α and the Wnt/β-catenin signaling pathway in a hypoxic environment. The study also aimed to explore the possible mechanisms underlying the invasion of hypoxic gastric cancer cells in vitro and in vivo. The pcDNA™ 6.2‑GW/EmGFP‑miR‑β‑catenin plasmid was transfected into SGC‑7901 gastric cancer cells, resulting in cells with stable suppression of β‑catenin expression. The biological characteristics of the control, liposome, negative control, β‑catenin knockdown, hypoxia and hypoxia β‑catenin knockdown groups were tested using an invasion assay. The differences in the invasive capacity of the control, negative control and liposome groups were not statistically significant. However, the hypoxia group demonstrated a significantly enhanced invasive capacity, as compared with that in the control group (Phypoxic and control cells was high alongside increased HIF‑1α, β‑catenin, uPA and MMP‑7 levels according to western blot and immunohistochemical analyses, while growth and protein levels of tumors from hypoxic β‑catenin knockdown cells were significantly lower and those of β‑catenin knockdown cells were lowest. In conclusion, these results suggested that HIF‑1α activation was able to regulate the Wnt/β‑catenin pathway, and that HIF‑1α may be controlled by the Wnt/β‑catenin pathway. A potential mechanism underlying SGC‑7901 tumorigenicity is the activation of the Wnt/β‑catenin signaling pathway, which activates uPA and MMP‑7 expression and contributes to the enhanced invasion of hypoxic cancer cells.

  7. Activation of the canonical Wnt pathway leads to loss of hematopoietic stem cell repopulation and multilineage differentiation block

    DEFF Research Database (Denmark)

    Kirstetter, Peggy; Anderson, Kristina; Porse, Bo T

    2006-01-01

    Wnt signaling increases hematopoietic stem cell self-renewal and is activated in both myeloid and lymphoid malignancies, indicating involvement in both normal and malignant hematopoiesis. We report here activated canonical Wnt signaling in the hematopoietic system through conditional expression...... of hematopoietic stem cell function was associated with decreased expression of Cdkn1a (encoding the cell cycle inhibitor p21(cdk)), Sfpi1, Hoxb4 and Bmi1 (encoding the transcription factors PU.1, HoxB4 and Bmi-1, respectively) and altered integrin expression in Lin(-)Sca-1(+)c-Kit(+) cells, whereas PU.1...... of a stable form of beta-catenin. This enforced expression led to hematopoietic failure associated with loss of myeloid lineage commitment at the granulocyte-macrophage progenitor stage; blocked erythrocyte differentiation; disruption of lymphoid development; and loss of repopulating stem cell activity. Loss...

  8. Long-Lasting WNT-TCF Response Blocking and Epigenetic Modifying Activities of Withanolide F in Human Cancer Cells.

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    Chandan Seth

    Full Text Available The WNT-TCF signaling pathway participates in adult tissue homeostasis and repair, and is hyperactive in a number of human diseases including cancers of the colon. Whereas to date there are no antagonists approved for patient use, a potential problem for their sustained use is the blockade of WNT signaling in healthy tissues, thus provoking potentially serious co-lateral damage. Here we have screened a library of plant and microorganism small molecules for novel WNT signaling antagonists and describe withanolide F as a potent WNT-TCF response blocker. This steroidal lactone inhibits TCF-dependent colon cancer xenograft growth and mimics the effects of genetic blockade of TCF and of ivermectin, a previously reported WNT-TCF blocker. However, withanolide F is unique in that it imposes a long-lasting repression of tumor growth, WNT-TCF targets and cancer stem cell clonogenicity after drug treatment. These findings are paralleled by its modulation of chromatin regulators and its alteration of overall H3K4me1 levels. Our results open up the possibility to permanently repress essential signaling responses in cancer cells through limited treatments with small molecules.

  9. Altered Wnt Signaling Pathway in Cognitive Impairment Caused by Chronic Intermittent Hypoxia: Focus on Glycogen Synthase Kinase-3β and β-catenin

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    Yue-Ying Pan

    2016-01-01

    Conclusions: Wnt/β-catenin signaling pathway abnormalities possibly play an important role in the development of cognitive deficits among mice exposed to CIH and that LiCl might attenuate CIH-induced cognitive impairment via Wnt/β-catenin signaling pathway.

  10. Liposomal packaging generates Wnt protein with in vivo biological activity.

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    Nathan T Morrell

    2008-08-01

    Full Text Available Wnt signals exercise strong cell-biological and regenerative effects of considerable therapeutic value. There are, however, no specific Wnt agonists and no method for in vivo delivery of purified Wnt proteins. Wnts contain lipid adducts that are required for activity and we exploited this lipophilicity by packaging purified Wnt3a protein into lipid vesicles. Rather than being encapsulated, Wnts are tethered to the liposomal surface, where they enhance and sustain Wnt signaling in vitro. Molecules that effectively antagonize soluble Wnt3a protein but are ineffective against the Wnt3a signal presented by a cell in a paracrine or autocrine manner are also unable to block liposomal Wnt3a activity, suggesting that liposomal packaging mimics the biological state of active Wnts. When delivered subcutaneously, Wnt3a liposomes induce hair follicle neogenesis, demonstrating their robust biological activity in a regenerative context.

  11. WNT Signaling Is Required for Peritoneal Membrane Angiogenesis.

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    Padwal, Manreet Kaur; Cheng, Genyang; Liu, Limin; Boivin, Felix J; Gangji, Azim; Brimble, Kenneth Scott; Bridgewater, Darren; Margetts, Peter J

    2018-01-24

    The WNT signaling pathway is involved in wound healing and fibrosis. We evaluated the WNT signaling pathway in peritoneal membrane injury. We assessed WNT1 protein expression in the peritoneal effluents of 54 stable peritoneal dialysis (PD) patients and WNT-related gene expression in ex vivo mesothelial cell cultures from 21 PD patients. In a transforming growth factor beta (TGFB) mediated animal model of peritoneal fibrosis, we evaluated regulation of the WNT pathway and the effect of WNT inhibition on peritoneal fibrosis and angiogenesis. WNT1 and WNT2 gene expression were positively correlated with peritoneal membrane solute transport in PD patients. In the mouse peritoneum, TGFΒ-induced peritoneal fibrosis was associated with increased expression of WNT2 and WNT4. Peritoneal b-catenin protein was significantly upregulated after infection with AdTGFB along with elements of the WNT signaling pathway. Treatment with a b-catenin inhibitor (ICG-001) in mice with AdTGFB-induced peritoneal fibrosis resulted in attenuation of peritoneal angiogenesis and reduced vascular endothelial growth factor. Similar results were also observed with the WNT antagonist Dickkopf related protein (DKK) 1. In addition to this, DKK-1 blocked epithelial to mesenchymal transition and increased levels of the cell adhesion protein E-cadherin. We provide evidence that WNT signaling is active in the setting of experimental peritoneal fibrosis and WNT1 correlates with patient peritoneal membrane solute transport in PD patients. Intervention in this pathway is a possible therapy for peritoneal membrane injury.

  12. Upregulation of Klotho potentially inhibits pulmonary vascular remodeling by blocking the activation of the Wnt signaling pathway in rats with PM2.5-induced pulmonary arterial hypertension.

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    Cong, Lu-Hong; Du, Shi-Yu; Wu, Yi-Na; Liu, Ying; Li, Tao; Wang, Hui; Li, Gang; Duan, Jun

    2018-01-30

    We evaluated the effects of Klotho on pulmonary vascular remodeling and cell proliferation and apoptosis in rat models with PM2.5-induced pulmonary arterial hypertension (PAH) via the Wnt signaling pathway. After establishing rat models of PM2.5-induced PAH, these Sprague-Dawley male rats were randomized into control and model groups. Cells extracted from the model rats were sub-categorized into different groups. Activation of Wnt/β-catenin signaling transcription factor was detected by a TOPFlash/FOPFlash assay. A serial of experiment was conducted to identify the mechanism of Klotho on PHA via the Wnt signaling pathway. VEGF levels and PaCO 2 content were higher in the model group, while PaO 2, NO 2 - /NO 3 - content and Klotho level was lower compared to the control group. In comparison to the control group, the model group had decreased Klotho and Bax levels, and elevated Wnt-1, β-catenin, bcl-2, survivin, and PCNA expression, VEGF, IL-6, TNF-α, TNF-β1, and bFGF levels, as well as the percentage of pulmonary artery ring contraction. The Klotho vector, DKK-1 and DKK-1 + Klotho vector groups exhibited reduced cell proliferation, luciferase activity, and the expression of Wnt-1, β-catenin, bcl-2, survivin, and PCNA, as well as shortened S phase compared with the blank and NC groups. Compared with the Klotho vector and DKK-1 groups, the DKK-1 + Klotho vector groups had reduced cell proliferation, luciferase activity, and the expression of Wnt-1, β-catenin, bcl-2, survivin, and PCNA, as well as a shortened S phase. Conclusively, Klotho inhibits pulmonary vascular remodeling by inactivation of Wnt signaling pathway. © 2018 Wiley Periodicals, Inc.

  13. WNT signalling and haematopoiesis: a WNT-WNT situation.

    NARCIS (Netherlands)

    Staal, F.J.T.; Clevers, J.C.

    2005-01-01

    The evolutionarily conserved WNT-signalling pathway has pivotal roles during the development of many organ systems, and dysregulated WNT signalling is a key factor in the initiation of various tumours. Recent studies have implicated a role for WNT signal transduction at several stages of lymphocyte

  14. Inhibition of Siah2 ubiquitin ligase by vitamin K3 (menadione) attenuates hypoxia and MAPK signaling and blocks melanoma tumorigenesis.

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    Shah, Meera; Stebbins, John L; Dewing, Antimone; Qi, Jianfei; Pellecchia, Maurizio; Ronai, Ze'ev A

    2009-12-01

    The E3 ubiquitin ligase Siah2 has been implicated in the regulation of the hypoxia response, as well as in the control of Ras, JNK/p38/NF-kappaB signaling pathways. Both Ras/mitogen-activated protein kinase (MAPK) and hypoxia pathways are important for melanoma development and progression, pointing to the possible use of Siah2 as target for treatment of this tumor type. In the present study, we have established a high-throughput electro-chemiluninescent-based assay in order to screen and identify inhibitors of Siah2 ubiquitin ligase activity. Of 1840 compounds screened, we identified and characterized menadione (MEN) as a specific inhibitor of Siah2 ligase activity. MEN attenuated Siah2 self-ubiquitination, and increased expression of its substrates PHD3 and Sprouty2, with concomitant decrease in levels of HIF-1alpha and pERK, the respective downstream effectors. MEN treatment no longer affected PHD3 or Sprouty2 in Siah-KO cells, pointing to its Siah-dependent effects. Further, MEN inhibition of Siah2 was not attenuated by free radical scavenger, suggesting it is ROS-independent. Significantly, growth of xenograft melanoma tumors was inhibited following the administration of MEN or its derivative. These findings reveal an efficient platform for the identification of Siah inhibitors while identifying and characterizing MEN as Siah inhibitor that attenuates hypoxia and MAPK signaling, and inhibits melanoma tumorigenesis.

  15. Inhibition of Siah2 ubiquitin ligase by vitamin K3 (menadione) attenuates hypoxia and MAPK signaling and blocks melanoma tumorigenesis

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    Shah, Meera; Stebbins, John L.; Dewing, Antimone; Qi, Jianfei; Pellecchia, Maurizio; Ronai, Ze’ev A.

    2010-01-01

    Summary The E3 ubiquitin ligase Siah2 has been implicated in the regulation of the hypoxia response, as well as in the control of Ras, JNK/p38/NF-κB signaling pathways. Both Ras/mitogen-activated protein kinase (MAPK) and hypoxia pathways are important for melanoma development and progression, pointing to the possible use of Siah2 as target for treatment of this tumor type. In the present study, we have established a high-throughput electro-chemiluninescent-based assay in order to screen and identify inhibitors of Siah2 ubiquitin ligase activity. Of 1840 compounds screened, we identified and characterized menadione (MEN) as a specific inhibitor of Siah2 ligase activity. MEN attenuated Siah2 self-ubiquitination, and increased expression of its substrates PHD3 and Sprouty2, with concomitant decrease in levels of HIF-1α and pERK, the respective downstream effectors. MEN treatment no longer affected PHD3 or Sprouty2 in Siah-KO cells, pointing to its Siah-dependent effects. Further, MEN inhibition of Siah2 was not attenuated by free radical scavenger, suggesting it is ROS-independent. Significantly, growth of xenograft melanoma tumors was inhibited following the administration of MEN or its derivative. These findings reveal an efficient platform for the identification of Siah inhibitors while identifying and characterizing MEN as Siah inhibitor that attenuates hypoxia and MAPK signaling, and inhibits melanoma tumorigenesis. PMID:19712206

  16. Hypoxia induces adipogenic differentitation of myoblastic cell lines

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    Itoigawa, Yoshiaki [Tohoku University School of Medicine, Sendai (Japan); Juntendo University School of Medicine, Tokyo (Japan); Kishimoto, Koshi N., E-mail: kishimoto@med.tohoku.ac.jp [Tohoku University School of Medicine, Sendai (Japan); Okuno, Hiroshi; Sano, Hirotaka [Tohoku University School of Medicine, Sendai (Japan); Kaneko, Kazuo [Juntendo University School of Medicine, Tokyo (Japan); Itoi, Eiji [Tohoku University School of Medicine, Sendai (Japan)

    2010-09-03

    Research highlights: {yields} C2C12 and G8 myogenic cell lines treated by hypoxia differentiate into adipocytes. {yields} The expression of C/EBP{beta}, {alpha} and PPAR{gamma} were increased under hypoxia. {yields} Myogenic differentiation of C2C12 was inhibited under hypoxia. -- Abstract: Muscle atrophy usually accompanies fat accumulation in the muscle. In such atrophic conditions as back muscles of kyphotic spine and the rotator cuff muscles with torn tendons, blood flow might be diminished. It is known that hypoxia causes trans-differentiation of mesenchymal stem cells derived from bone marrow into adipocytes. However, it has not been elucidated yet if hypoxia turned myoblasts into adipocytes. We investigated adipogenesis in C2C12 and G8 murine myogenic cell line treated by hypoxia. Cells were also treated with the cocktail of insulin, dexamethasone and IBMX (MDI), which has been known to inhibit Wnt signaling and promote adipogenesis. Adipogenic differentiation was seen in both hypoxia and MDI. Adipogenic marker gene expression was assessed in C2C12. CCAAT/enhancer-binding protein (C/EBP) {beta}, {alpha} and peroxisome proliferator activating receptor (PPAR) {gamma} were increased by both hypoxia and MDI. The expression profile of Wnt10b was different between hypoxia and MDI. The mechanism for adipogenesis of myoblasts in hypoxia might be regulated by different mechanism than the modification of Wnt signaling.

  17. Wise retained in the endoplasmic reticulum inhibits Wnt signaling by reducing cell surface LRP6.

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    Guidato, Sonia; Itasaki, Nobue

    2007-10-15

    The Wnt signaling pathway is tightly regulated by extracellular and intracellular modulators. Wise was isolated as a secreted protein capable of interacting with the Wnt co-receptor LRP6. Studies in Xenopus embryos revealed that Wise either enhances or inhibits the Wnt pathway depending on the cellular context. Here we show that the cellular localization of Wise has distinct effects on the Wnt pathway readout. While secreted Wise either synergizes or inhibits the Wnt signals depending on the partner ligand, ER-retained Wise consistently blocks the Wnt pathway. ER-retained Wise reduces LRP6 on the cell surface, making cells less susceptible to the Wnt signal. This study provides a cellular mechanism for the action of Wise and introduces the modulation of cellular susceptibility to Wnt signals as a novel mechanism of the regulation of the Wnt pathway.

  18. Common activation of canonical Wnt signaling in pancreatic adenocarcinoma.

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    Marina Pasca di Magliano

    2007-11-01

    Full Text Available Pancreatic ductal adenocarcinoma (PDA is an extremely aggressive malignancy, which carries a dismal prognosis. Activating mutations of the Kras gene are common to the vast majority of human PDA. In addition, recent studies have demonstrated that embryonic signaling pathway such as Hedgehog and Notch are inappropriately upregulated in this disease. The role of another embryonic signaling pathway, namely the canonical Wnt cascade, is still controversial. Here, we use gene array analysis as a platform to demonstrate general activation of the canonical arm of the Wnt pathway in human PDA. Furthermore, we provide evidence for Wnt activation in mouse models of pancreatic cancer. Our results also indicate that Wnt signaling might be activated downstream of Hedgehog signaling, which is an early event in PDA evolution. Wnt inhibition blocked proliferation and induced apoptosis of cultured adenocarcinoma cells, thereby providing evidence to support the development of novel therapeutical strategies for Wnt inhibition in pancreatic adenocarcinoma.

  19. Wnt signaling in cancer

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    Zhan, T; Rindtorff, N; Boutros, M

    2017-01-01

    Wnt signaling is one of the key cascades regulating development and stemness, and has also been tightly associated with cancer. The role of Wnt signaling in carcinogenesis has most prominently been described for colorectal cancer, but aberrant Wnt signaling is observed in many more cancer entities. Here, we review current insights into novel components of Wnt pathways and describe their impact on cancer development. Furthermore, we highlight expanding functions of Wnt signaling for both solid and liquid tumors. We also describe current findings how Wnt signaling affects maintenance of cancer stem cells, metastasis and immune control. Finally, we provide an overview of current strategies to antagonize Wnt signaling in cancer and challenges that are associated with such approaches. PMID:27617575

  20. Hypoxia Room

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    Federal Laboratory Consortium — The Hypoxia Room is a 8x8x8 ft. clear vinyl plastic and aluminum frame construction enclosure located within USAREIM laboratory 028. The Hypoxia Room (manufactured...

  1. Successful tumour necrosis factor (TNF) blocking therapy suppresses oxidative stress and hypoxia-induced mitochondrial mutagenesis in inflammatory arthritis

    LENUS (Irish Health Repository)

    Biniecka, Monika

    2011-07-25

    Abstract Introduction To examine the effects of tumour necrosis factor (TNF) blocking therapy on the levels of early mitochondrial genome alterations and oxidative stress. Methods Eighteen inflammatory arthritis patients underwent synovial tissue oxygen (tpO2) measurements and clinical assessment of disease activity (DAS28-CRP) at baseline (T0) and three months (T3) after starting biologic therapy. Synovial tissue lipid peroxidation (4-HNE), T and B cell specific markers and synovial vascular endothelial growth factor (VEGF) were quantified by immunohistochemistry. Synovial levels of random mitochondrial DNA (mtDNA) mutations were assessed using Random Mutation Capture (RMC) assay. Results 4-HNE levels pre\\/post anti TNF-α therapy were inversely correlated with in vivo tpO2 (P < 0.008; r = -0.60). Biologic therapy responders showed a significantly reduced 4-HNE expression (P < 0.05). High 4-HNE expression correlated with high DAS28-CRP (P = 0.02; r = 0.53), tender joint count for 28 joints (TJC-28) (P = 0.03; r = 0.49), swollen joint count for 28 joints (SJC-28) (P = 0.03; r = 0.50) and visual analogue scale (VAS) (P = 0.04; r = 0.48). Strong positive association was found between the number of 4-HNE positive cells and CD4+ cells (P = 0.04; r = 0.60), CD8+ cells (P = 0.001; r = 0.70), CD20+ cells (P = 0.04; r = 0.68), CD68+ cells (P = 0.04; r = 0.47) and synovial VEGF expression (P = 0.01; r = 063). In patients whose in vivo tpO2 levels improved post treatment, significant reduction in mtDNA mutations and DAS28-CRP was observed (P < 0.05). In contrast in those patients whose tpO2 levels remained the same or reduced at T3, no significant changes for mtDNA mutations and DAS28-CRP were found. Conclusions High levels of synovial oxidative stress and mitochondrial mutation burden are strongly associated with low in vivo oxygen tension and synovial inflammation. Furthermore these significant mitochondrial genome alterations are rescued following successful anti TNF

  2. Updating the Wnt pathways

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    Yu, Jia; Virshup, David M.

    2014-01-01

    In the three decades since the discovery of the Wnt1 proto-oncogene in virus-induced mouse mammary tumours, our understanding of the signalling pathways that are regulated by the Wnt proteins has progressively expanded. Wnts are involved in an complex signalling network that governs multiple biological processes and cross-talk with multiple additional signalling cascades, including the Notch, FGF (fibroblast growth factor), SHH (Sonic hedgehog), EGF (epidermal growth factor) and Hippo pathways. The Wnt signalling pathway also illustrates the link between abnormal regulation of the developmental processes and disease manifestation. Here we provide an overview of Wnt-regulated signalling cascades and highlight recent advances. We focus on new findings regarding the dedicated Wnt production and secretion pathway with potential therapeutic targets that might be beneficial for patients with Wnt-related diseases. PMID:25208913

  3. APC Inhibits Ligand-Independent Wnt Signaling by the Clathrin Endocytic Pathway.

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    Saito-Diaz, Kenyi; Benchabane, Hassina; Tiwari, Ajit; Tian, Ai; Li, Bin; Thompson, Joshua J; Hyde, Annastasia S; Sawyer, Leah M; Jodoin, Jeanne N; Santos, Eduardo; Lee, Laura A; Coffey, Robert J; Beauchamp, R Daniel; Williams, Christopher S; Kenworthy, Anne K; Robbins, David J; Ahmed, Yashi; Lee, Ethan

    2018-03-12

    Adenomatous polyposis coli (APC) mutations cause Wnt pathway activation in human cancers. Current models for APC action emphasize its role in promoting β-catenin degradation downstream of Wnt receptors. Unexpectedly, we find that blocking Wnt receptor activity in APC-deficient cells inhibits Wnt signaling independently of Wnt ligand. We also show that inducible loss of APC is rapidly followed by Wnt receptor activation and increased β-catenin levels. In contrast, APC2 loss does not promote receptor activation. We show that APC exists in a complex with clathrin and that Wnt pathway activation in APC-deficient cells requires clathrin-mediated endocytosis. Finally, we demonstrate conservation of this mechanism in Drosophila intestinal stem cells. We propose a model in which APC and APC2 function to promote β-catenin degradation, and APC also acts as a molecular "gatekeeper" to block receptor activation via the clathrin pathway. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Wnt is necessary for mesenchymal to epithelial transition in colorectal cancer cells.

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    Schwab, Renate H M; Amin, Nancy; Flanagan, Dustin J; Johanson, Timothy M; Phesse, Toby J; Vincan, Elizabeth

    2018-03-01

    Metastasis underlies most colorectal cancer mortality. Cancer cells spread through the body as single cells or small clusters of cells that have an invasive, mesenchymal, nonproliferative phenotype. At the secondary site, they revert to a proliferative "tumor constructing" epithelial phenotype to rebuild a tumor. We previously developed a unique in vitro three-dimensional model, called LIM1863-Mph, which faithfully recapitulates these reversible transitions that underpin colorectal cancer metastasis. Wnt signaling plays a key role in these transitions and is initiated by the coupling of extracellular Wnt to Frizzled (FZD). Using the LIM1863-Mph model system we demonstrated that the Wnt receptor FZD7 is necessary for mesenchymal to epithelial transition (MET). Here we investigate the role of Wnt in MET. Wnt secretion is dependent on palmitoylation by Porcupine (PORC). A PORC inhibitor (IWP2) that prevents Wnt secretion, blocked the epithelial transition of mesenchymal LIM1863-Mph cells. Wnt gene array analysis identified several Wnts that are upregulated in epithelial compared with mesenchymal LIM1863-Mph cells, suggesting these ligands in MET. Wnt2B was the most abundant differentially expressed Wnt gene. Indeed, recombinant Wnt2B could overcome the IWP2-mediated block in epithelial transition of mesenchymal LIM1863-Mph cells. Wnt2B co-operates with Frizzled7 to mediate MET in colorectal cancer. Developmental Dynamics 247:521-530, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Wnt5a regulates midbrain dopaminergic axon growth and guidance.

    Directory of Open Access Journals (Sweden)

    Brette D Blakely

    2011-03-01

    Full Text Available During development, precise temporal and spatial gradients are responsible for guiding axons to their appropriate targets. Within the developing ventral midbrain (VM the cues that guide dopaminergic (DA axons to their forebrain targets remain to be fully elucidated. Wnts are morphogens that have been identified as axon guidance molecules. Several Wnts are expressed in the VM where they regulate the birth of DA neurons. Here, we describe that a precise temporo-spatial expression of Wnt5a accompanies the development of nigrostriatal projections by VM DA neurons. In mice at E11.5, Wnt5a is expressed in the VM where it was found to promote DA neurite and axonal growth in VM primary cultures. By E14.5, when DA axons are approaching their striatal target, Wnt5a causes DA neurite retraction in primary cultures. Co-culture of VM explants with Wnt5a-overexpressing cell aggregates revealed that Wnt5a is capable of repelling DA neurites. Antagonism experiments revealed that the effects of Wnt5a are mediated by the Frizzled receptors and by the small GTPase, Rac1 (a component of the non-canonical Wnt planar cell polarity pathway. Moreover, the effects were specific as they could be blocked by Wnt5a antibody, sFRPs and RYK-Fc. The importance of Wnt5a in DA axon morphogenesis was further verified in Wnt5a-/- mice, where fasciculation of the medial forebrain bundle (MFB as well as the density of DA neurites in the MFB and striatal terminals were disrupted. Thus, our results identify a novel role of Wnt5a in DA axon growth and guidance.

  6. Unterschiede und Gemeinsamkeiten der nicht-kanonischen Wnt-Liganden Wnt5a und Wnt11

    OpenAIRE

    Wallkamm, Veronika

    2014-01-01

    Die nicht-kanonischen Zweige des Wnt-Signalnetzwerkes sind Regulatoren der konvergenten Extension während der Xenopus Gastrulation. Dabei übernehmen die nicht-kanonischen Wnt-Liganden Wnt5a und Wnt11 nicht-redundante Aufgaben.

  7. Wnt Signaling in Renal Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Qi Xu

    2016-06-01

    Full Text Available Renal cell carcinoma (RCC accounts for 90% of all kidney cancers. Due to poor diagnosis, high resistance to the systemic therapies and the fact that most RCC cases occur sporadically, current research switched its focus on studying the molecular mechanisms underlying RCC. The aim is the discovery of new effective and less toxic anti-cancer drugs and novel diagnostic markers. Besides the PI3K/Akt/mTOR, HGF/Met and VHL/hypoxia cellular signaling pathways, the involvement of the Wnt/β-catenin pathway in RCC is commonly studied. Wnt signaling and its targeted genes are known to actively participate in different biological processes during embryonic development and renal cancer. Recently, studies have shown that targeting this pathway by alternating/inhibiting its intracellular signal transduction can reduce cancer cells viability and inhibit their growth. The targets and drugs identified show promising potential to serve as novel RCC therapeutics and prognostic markers. This review aims to summarize the current status quo regarding recent research on RCC focusing on the involvement of the Wnt/β-catenin pathway and how its understanding could facilitate the identification of potential therapeutic targets, new drugs and diagnostic biomarkers.

  8. Both canonical and non-canonical Wnt signaling independently promote stem cell growth in mammospheres.

    Directory of Open Access Journals (Sweden)

    Alexander M Many

    Full Text Available The characterization of mammary stem cells, and signals that regulate their behavior, is of central importance in understanding developmental changes in the mammary gland and possibly for targeting stem-like cells in breast cancer. The canonical Wnt/β-catenin pathway is a signaling mechanism associated with maintenance of self-renewing stem cells in many tissues, including mammary epithelium, and can be oncogenic when deregulated. Wnt1 and Wnt3a are examples of ligands that activate the canonical pathway. Other Wnt ligands, such as Wnt5a, typically signal via non-canonical, β-catenin-independent, pathways that in some cases can antagonize canonical signaling. Since the role of non-canonical Wnt signaling in stem cell regulation is not well characterized, we set out to investigate this using mammosphere formation assays that reflect and quantify stem cell properties. Ex vivo mammosphere cultures were established from both wild-type and Wnt1 transgenic mice and were analyzed in response to manipulation of both canonical and non-canonical Wnt signaling. An increased level of mammosphere formation was observed in cultures derived from MMTV-Wnt1 versus wild-type animals, and this was blocked by treatment with Dkk1, a selective inhibitor of canonical Wnt signaling. Consistent with this, we found that a single dose of recombinant Wnt3a was sufficient to increase mammosphere formation in wild-type cultures. Surprisingly, we found that Wnt5a also increased mammosphere formation in these assays. We confirmed that this was not caused by an increase in canonical Wnt/β-catenin signaling but was instead mediated by non-canonical Wnt signals requiring the receptor tyrosine kinase Ror2 and activity of the Jun N-terminal kinase, JNK. We conclude that both canonical and non-canonical Wnt signals have positive effects promoting stem cell activity in mammosphere assays and that they do so via independent signaling mechanisms.

  9. Illegitimate WNT signaling promotes proliferation of multiple myeloma cells

    Science.gov (United States)

    Derksen, Patrick W. B.; Tjin, Esther; Meijer, Helen P.; Klok, Melanie D.; Mac Gillavry, Harold D.; van Oers, Marinus H. J.; Lokhorst, Henk M.; Bloem, Andries C.; Clevers, Hans; Nusse, Roel; van der Neut, Ronald; Spaargaren, Marcel; Pals, Steven T.

    2004-01-01

    The unrestrained growth of tumor cells is generally attributed to mutations in essential growth control genes, but tumor cells are also influenced by signals from the environment. In multiple myeloma (MM), the factors and signals coming from the bone marrow microenvironment are possibly even essential for the growth of the tumor cells. As targets for intervention, these signals may be equally important as mutated oncogenes. Given their oncogenic potential, WNT signals form a class of paracrine growth factors that could act to influence MM cell growth. In this paper, we report that MM cells have hallmarks of active WNT signaling, whereas the cells have not undergone detectable mutations in WNT signaling genes such as adenomatous polyposis coli and β-catenin (CTNNB1). We show that the malignant MM plasma cells overexpress β-catenin, including its N-terminally unphosphorylated form, suggesting active β-catenin/T cell factor-mediated transcription. Further accumulation and nuclear localization of β-catenin, and/or increased cell proliferation, was achieved by stimulation of WNT signaling with either Wnt3a, LiCl, or the constitutively active S33Y mutant of β-catenin. In contrast, by blocking WNT signaling by dominant-negative T cell factor, we can interfere with the growth of MM cells. We therefore suggest that MM cells are dependent on an active WNT signal, which may have important implications for the management of this incurable form of cancer. PMID:15067127

  10. Wnt/beta-Catenin Signaling and Small Molecule Inhibitors

    Science.gov (United States)

    Voronkov, Andrey; Krauss, Stefan

    2012-01-01

    Wnt/β-catenin signaling is a branch of a functional network that dates back to the first metazoans and it is involved in a broad range of biological systems including stem cells, embryonic development and adult organs. Deregulation of components involved in Wnt/β-catenin signaling has been implicated in a wide spectrum of diseases including a number of cancers and degenerative diseases. The key mediator of Wnt signaling, β-catenin, serves several cellular functions. It functions in a dynamic mode at multiple cellular locations, including the plasma membrane, where β-catenin contributes to the stabilization of intercellular adhesive complexes, the cytoplasm where β-catenin levels are regulated and the nucleus where β-catenin is involved in transcriptional regulation and chromatin interactions. Central effectors of β-catenin levels are a family of cysteine-rich secreted glycoproteins, known as Wnt morphogens. Through the LRP5/6-Frizzled receptor complex, Wnts regulate the location and activity of the destruction complex and consequently intracellular β- catenin levels. However, β-catenin levels and their effects on transcriptional programs are also influenced by multiple other factors including hypoxia, inflammation, hepatocyte growth factor-mediated signaling, and the cell adhesion molecule E-cadherin. The broad implications of Wnt/β-catenin signaling in development, in the adult body and in disease render the pathway a prime target for pharmacological research and development. The intricate regulation of β-catenin at its various locations provides alternative points for therapeutic interventions. PMID:23016862

  11. Wnt signaling in limb organogenesis

    OpenAIRE

    Geetha-Loganathan, Poongodi; Nimmagadda, Suresh; Scaal, Martin

    2008-01-01

    Secreted signaling molecules of the Wnt family have been found to play a central role in controlling embryonic development of a wide range of taxa from Hydra to humans. The most extensively studied Wnt signaling pathway is the canonical Wnt pathway, which controls gene expression by stabilizing β-catenin, and regulates a multitude of developmental processes. More recently, noncanonical Wnt pathways, which are β-catenin-independent, have been found to be important developmental regulators. Und...

  12. WNT4 mediates estrogen receptor signaling and endocrine resistance in invasive lobular carcinoma cell lines.

    Science.gov (United States)

    Sikora, Matthew J; Jacobsen, Britta M; Levine, Kevin; Chen, Jian; Davidson, Nancy E; Lee, Adrian V; Alexander, Caroline M; Oesterreich, Steffi

    2016-09-20

    Invasive lobular carcinoma (ILC) of the breast typically presents with clinical biomarkers consistent with a favorable response to endocrine therapies, and over 90 % of ILC cases express the estrogen receptor (ER). However, a subset of ILC cases may be resistant to endocrine therapies, suggesting that ER biology is unique in ILC. Using ILC cell lines, we previously demonstrated that ER regulates a distinct gene expression program in ILC cells, and we hypothesized that these ER-driven pathways modulate the endocrine response in ILC. One potential novel pathway is via the Wnt ligand WNT4, a critical signaling molecule in mammary gland development regulated by the progesterone receptor. The ILC cell lines MDA-MB-134-VI, SUM44PE, and BCK4 were used to assess WNT4 gene expression and regulation, as well as the role of WNT4 in estrogen-regulated proliferation. To assess these mechanisms in the context of endocrine resistance, we developed novel ILC endocrine-resistant long-term estrogen-deprived (ILC-LTED) models. ILC and ILC-LTED cell lines were used to identify upstream regulators and downstream signaling effectors of WNT4 signaling. ILC cells co-opted WNT4 signaling by placing it under direct ER control. We observed that ER regulation of WNT4 correlated with use of an ER binding site at the WNT4 locus, specifically in ILC cells. Further, WNT4 was required for endocrine response in ILC cells, as WNT4 knockdown blocked estrogen-induced proliferation. ILC-LTED cells remained dependent on WNT4 for proliferation, by either maintaining ER function and WNT4 regulation or uncoupling WNT4 from ER and upregulating WNT4 expression. In the latter case, WNT4 expression was driven by activated nuclear factor kappa-B signaling in ILC-LTED cells. In ILC and ILC-LTED cells, WNT4 led to suppression of CDKN1A/p21, which is critical for ILC cell proliferation. CDKN1A knockdown partially reversed the effects of WNT4 knockdown. WNT4 drives a novel signaling pathway in ILC cells, with a

  13. Wnt5a regulates hematopoietic stem cell proliferation and repopulation through the Ryk receptor.

    Science.gov (United States)

    Povinelli, Benjamin J; Nemeth, Michael J

    2014-01-01

    Proper regulation of the balance between hematopoietic stem cell (HSC) proliferation, self-renewal, and differentiation is necessary to maintain hematopoiesis throughout life. The Wnt family of ligands has been implicated as critical regulators of these processes through a network of signaling pathways. Previously, we have demonstrated that the Wnt5a ligand can induce HSC quiescence through a noncanonical Wnt pathway, resulting in an increased ability to reconstitute hematopoiesis. In this study, we tested the hypothesis that the Ryk protein, a Wnt ligand receptor that can bind the Wnt5a ligand, regulated the response of HSCs to Wnt5a. We observed that inhibiting Ryk blocked the ability of Wnt5a to induce HSC quiescence and enhance short-term and long-term hematopoietic repopulation. We found that Wnt5a suppressed production of reactive oxygen species, a known inducer of HSC proliferation. The ability of Wnt5a to inhibit ROS production was also regulated by Ryk. From these data, we propose that Wnt5a regulates HSC quiescence and hematopoietic repopulation through the Ryk receptor and that this process is mediated by suppression of reactive oxygen species. © 2013 AlphaMed Press.

  14. Inhibition of canonical WNT signaling attenuates human leiomyoma cell growth

    Science.gov (United States)

    Ono, Masanori; Yin, Ping; Navarro, Antonia; Moravek, Molly B.; Coon, John S.; Druschitz, Stacy A.; Gottardi, Cara J.; Bulun, Serdar E.

    2014-01-01

    Objective Dysregulation of WNT signaling plays a central role in tumor cell growth and progression. Our goal was to assess the effect of three WNT/β-catenin pathway inhibitors, Inhibitor of β-Catenin And TCF4 (ICAT), niclosamide, and XAV939 on the proliferation of primary cultures of human uterine leiomyoma cells. Design Prospective study of human leiomyoma cells obtained from myomectomy or hysterectomy. Setting University research laboratory. Patient(s) Women (n=38) aged 27–53 years undergoing surgery. Intervention(s) Adenoviral ICAT overexpression or treatment with varying concentrations of niclosamide or XAV939. Main Outcome Measure(s) Cell proliferation, cell death, WNT/β-catenin target gene expression or reporter gene regulation, β-catenin levels and cellular localization. Result(s) ICAT, niclosamide, or XAV939 inhibit WNT/β-catenin pathway activation and exert anti-proliferative effects in primary cultures of human leiomyoma cells. Conclusion(s) Three WNT/β-catenin pathway inhibitors specifically block human leiomyoma growth and proliferation, suggesting that the canonical WNT pathway may be a potential therapeutic target for the treatment of uterine leiomyoma. Our findings provide rationale for further preclinical and clinical evaluation of ICAT, niclosamide, and XAV939 as candidate anti-tumor agents for uterine leiomyoma. PMID:24534281

  15. Secreted and Transmembrane Wnt Inhibitors and Activators

    Science.gov (United States)

    Cruciat, Cristina-Maria; Niehrs, Christof

    2013-01-01

    Signaling by the Wnt family of secreted glycoproteins plays important roles in embryonic development and adult homeostasis. Wnt signaling is modulated by a number of evolutionarily conserved inhibitors and activators. Wnt inhibitors belong to small protein families, including sFRP, Dkk, WIF, Wise/SOST, Cerberus, IGFBP, Shisa, Waif1, APCDD1, and Tiki1. Their common feature is to antagonize Wnt signaling by preventing ligand–receptor interactions or Wnt receptor maturation. Conversely, the Wnt activators, R-spondin and Norrin, promote Wnt signaling by binding to Wnt receptors or releasing a Wnt-inhibitory step. With few exceptions, these antagonists and agonists are not pure Wnt modulators, but also affect additional signaling pathways, such as TGF-β and FGF signaling. Here we discuss their interactions with Wnt ligands and Wnt receptors, their role in developmental processes, as well as their implication in disease. PMID:23085770

  16. Dual Function of Wnt Signaling during Neuronal Differentiation of Mouse Embryonic Stem Cells

    Directory of Open Access Journals (Sweden)

    Hanjun Kim

    2015-01-01

    Full Text Available Activation of Wnt signaling enhances self-renewal of mouse embryonic and neural stem/progenitor cells. In contrast, undifferentiated ES cells show a very low level of endogenous Wnt signaling, and ectopic activation of Wnt signaling has been shown to block neuronal differentiation. Therefore, it remains unclear whether or not endogenous Wnt/β-catenin signaling is necessary for self-renewal or neuronal differentiation of ES cells. To investigate this, we examined the expression profiles of Wnt signaling components. Expression levels of Wnts known to induce β-catenin were very low in undifferentiated ES cells. Stable ES cell lines which can monitor endogenous activity of Wnt/β-catenin signaling suggest that Wnt signaling was very low in undifferentiated ES cells, whereas it increased during embryonic body formation or neuronal differentiation. Interestingly, application of small molecules which can positively (BIO, GSK3β inhibitor or negatively (IWR-1-endo, Axin stabilizer control Wnt/β-catenin signaling suggests that activation of that signaling at different time periods had differential effects on neuronal differentiation of 46C ES cells. Further, ChIP analysis suggested that β-catenin/TCF1 complex directly regulated the expression of Sox1 during neuronal differentiation. Overall, our data suggest that Wnt/β-catenin signaling plays differential roles at different time points of neuronal differentiation.

  17. Neuroprotective and regenerative roles of intranasal Wnt-3a administration after focal ischemic stroke in mice.

    Science.gov (United States)

    Wei, Zheng Zachory; Zhang, James Ya; Taylor, Tammi M; Gu, Xiaohuan; Zhao, Yingying; Wei, Ling

    2018-03-01

    Wnt signaling is a conserved pathway involved in expansion of neural progenitors and lineage specification during development. However, the role of Wnt signaling in the post-stroke brain has not been well-elucidated. We hypothesized that Wnt-3a would play an important role for neurogenesis and brain repair. Adult male mice were subjected to a focal ischemic stroke targeting the sensorimotor cortex. Mice that received Wnt-3a (2 µg/kg/day, 1 h after stroke and once a day for the next 2 days, intranasal delivery) had reduced infarct volume compared to stroke controls. Wnt-3a intranasal treatment of seven days upregulated the expression of brain-derived growth factor (BDNF), increased the proliferation and migration of neuroblasts from the subventricular zone (SVZ), resulting in increased numbers of newly formed neurons and endothelial cells in the peri-infarct zone. Both the molecular and cellular effects of Wnt-3a were blocked by the Wnt specific inhibitors XAV-939 or Dkk-1. In functional assays, Wnt-3a treatment enhanced the local cerebral blood flow (LCBF) in the peri-infarct, as well as improved sensorimotor functions in a battery of behavioral tests. Together, our data demonstrates that the Wnt-3a signaling can act as a dual neuroprotective and regenerative factor for the treatment of ischemic stroke.

  18. Targeting Wnt Pathways in Disease

    Science.gov (United States)

    Zimmerman, Zachary F.; Moon, Randall T.

    2012-01-01

    Wnt-mediated signal transduction pathways have long been recognized for their roles in regulating embryonic development, and have more recently been linked to cancer, neurologic diseases, inflammatory diseases, and disorders of endocrine function and bone metabolism in adults. Although therapies targeting Wnt signaling are attractive in theory, in practice it has been difficult to obtain specific therapeutics because many components of Wnt signaling pathways are also involved in other cellular processes, thereby reducing the specificity of candidate therapeutics. New technologies, and advances in understanding the mechanisms of Wnt signaling, have improved our understanding of the nuances of Wnt signaling and are leading to promising new strategies to target Wnt signaling pathways. PMID:23001988

  19. Wnt1 Neuroprotection Translates into Improved Neurological Function during Oxidant Stress and Cerebral Ischemia Through AKT1 and Mitochondrial Apoptotic Pathways

    Directory of Open Access Journals (Sweden)

    Zhao Zhong Chong

    2010-01-01

    Full Text Available Although essential for the development of the nervous system, Wnt1 also has been associated with neurodegenerative disease and cognitive loss during periods of oxidative stress. Here we show that endogenous expression of Wnt1 is suppressed during oxidative stress in both in vitro and in vivo experimental models. Loss of endogenous Wnt1 signaling directly correlates with neuronal demise and increased functional deficit, illustrating that endogenous neuronal Wnt1 offers a vital level of intrinsic cellular protection against oxidative stress. Furthermore, transient overexpression of Wnt1 or application of exogenous Wnt1 recombinant protein is necessary to preserve neurological function and rescue neurons from apoptotic membrane phosphatidylserine externalization and genomic DNA degradation, since blockade of Wnt1 signaling with a Wnt1 antibody or dickkopf related protein 1 abrogates neuronal protection by Wnt1. Wnt1 ultimately relies upon the activation of Akt1, the modulation of mitochondrial membrane permeability, and the release of cytochrome c to control the apoptotic cascade, since inhibition of Wnt1 signaling, the phosphatidylinositol 3-kinase pathway, or Akt1 activity abrogates the ability of Wnt1 to block these apoptotic components. Our work identifies Wnt1 and its downstream signaling as cellular targets with high clinical potential for novel treatment strategies for multiple disorders precipitated by oxidative stress.

  20. Aberrant Wnt Signaling in Leukemia

    Directory of Open Access Journals (Sweden)

    Frank J. T. Staal

    2016-08-01

    Full Text Available The Wnt signaling pathway is essential in the development and homeostasis of blood and immune cells, but its exact role is still controversial and is the subject of intense research. The malignant counterpart of normal hematopoietic cells, leukemic (stem cells, have hijacked the Wnt pathway for their self-renewal and proliferation. Here we review the multiple ways dysregulated Wnt signaling can contribute to leukemogenesis, both cell autonomously as well as by changes in the microenvironment.

  1. Intermittent Hypoxia Causes Inflammation and Injury to Human Adult Cardiac Myocytes.

    Science.gov (United States)

    Wu, Jing; Stefaniak, Joanna; Hafner, Christina; Schramel, Johannes Peter; Kaun, Christoph; Wojta, Johann; Ullrich, Roman; Tretter, Verena Eva; Markstaller, Klaus; Klein, Klaus Ulrich

    2016-02-01

    Intermittent hypoxia may occur in a number of clinical scenarios, including interruption of myocardial blood flow or breathing disorders such as obstructive sleep apnea. Although intermittent hypoxia has been linked to cardiovascular and cerebrovascular disease, the effect of intermittent hypoxia on the human heart is not fully understood. Therefore, in the present study, we compared the cellular responses of cultured human adult cardiac myocytes (HACMs) exposed to intermittent hypoxia and different conditions of continuous hypoxia and normoxia. HACMs were exposed to intermittent hypoxia (0%-21% O2), constant mild hypoxia (10% O2), constant severe hypoxia (0% O2), or constant normoxia (21% O2), using a novel cell culture bioreactor with gas-permeable membranes. Cell proliferation, lactate dehydrogenase release, vascular endothelial growth factor release, and cytokine (interleukin [IL] and macrophage migration inhibitory factor) release were assessed at baseline and after 8, 24, and 72 hours of exposure. A signal transduction pathway finder array was performed to determine the changes in gene expression. In comparison with constant normoxia and constant mild hypoxia, intermittent hypoxia induced earlier and greater inflammatory response and extent of cell injury as evidenced by lower cell numbers and higher lactate dehydrogenase, vascular endothelial growth factor, and proinflammatory cytokine (IL-1β, IL-6, IL-8, and macrophage migration inhibitory factor) release. Constant severe hypoxia showed more detrimental effects on HACMs at later time points. Pathway analysis demonstrated that intermittent hypoxia primarily altered gene expression in oxidative stress, Wnt, Notch, and hypoxia pathways. Intermittent and constant severe hypoxia, but not constant mild hypoxia or normoxia, induced inflammation and cell injury in HACMs. Cell injury occurred earliest and was greatest after intermittent hypoxia exposure. Our in vitro findings suggest that intermittent hypoxia

  2. Vasculogenesis and angiogenesis initiation under normoxic conditions through Wnt/β-catenin pathway in gliomas.

    Science.gov (United States)

    Vallée, Alexandre; Guillevin, Rémy; Vallée, Jean-Noël

    2018-01-26

    The canonical Wnt/β-catenin pathway is up-regulated in gliomas and involved in proliferation, invasion, apoptosis, vasculogenesis and angiogenesis. Nuclear β-catenin accumulation correlates with malignancy. Hypoxia activates hypoxia-inducible factor (HIF)-1α by inhibiting HIF-1α prolyl hydroxylation, which promotes glycolytic energy metabolism, vasculogenesis and angiogenesis, whereas HIF-1α is degraded by the HIF prolyl hydroxylase under normoxic conditions. We focus this review on the links between the activated Wnt/β-catenin pathway and the mechanisms underlying vasculogenesis and angiogenesis through HIF-1α under normoxic conditions in gliomas. Wnt-induced epidermal growth factor receptor/phosphatidylinositol 3-kinase (PI3K)/Akt signaling, Wnt-induced signal transducers and activators of transcription 3 (STAT3) signaling, and Wnt/β-catenin target gene transduction (c-Myc) can activate HIF-1α in a hypoxia-independent manner. The PI3K/Akt/mammalian target of rapamycin pathway activates HIF-1α through eukaryotic translation initiation factor 4E-binding protein 1 and STAT3. The β-catenin/T-cell factor 4 complex directly binds to STAT3 and activates HIF-1α, which up-regulates the Wnt/β-catenin target genes cyclin D1 and c-Myc in a positive feedback loop. Phosphorylated STAT3 by interleukin-6 or leukemia inhibitory factor activates HIF-1α even under normoxic conditions. The activation of the Wnt/β-catenin pathway induces, via the Wnt target genes c-Myc and cyclin D1 or via HIF-1α, gene transactivation encoding aerobic glycolysis enzymes, such as glucose transporter, hexokinase 2, pyruvate kinase M2, pyruvate dehydrogenase kinase 1 and lactate dehydrogenase-A, leading to lactate production, as the primary alternative of ATP, at all oxygen levels, even in normoxic conditions. Lactate released by glioma cells via the monocarboxylate lactate transporter-1 up-regulated by HIF-1α and lactate anion activates HIF-1α in normoxic endothelial cells by

  3. Unraveling the Wnt secretion pathway

    NARCIS (Netherlands)

    Harterink, M.

    2011-01-01

    The Wnt family of signaling proteins has essential functions in development and adult tissue homeostasis throughout the animal kingdom. Although signaling cascades triggered by Wnt proteins have been extensively studied, much remains to be learned about how Wnts are produced and secreted and how

  4. Conditional expression of Wnt4 during chondrogenesis leads to dwarfism in mice.

    Directory of Open Access Journals (Sweden)

    Hu-Hui Lee

    Full Text Available Wnts are expressed in the forming long bones, suggesting roles in skeletogenesis. To examine the action of Wnts in skeleton formation, we developed a genetic system to conditionally express Wnt4 in chondrogenic tissues of the mouse. A mouse Wnt4 cDNA was introduced into the ubiquitously expressed Rosa26 (R26 locus by gene targeting in embryonic stem (ES cells. The expression of Wnt4 from the R26 locus was blocked by a neomycin selection cassette flanked by loxP sites (floxneo that was positioned between the Rosa26 promoter and the Wnt4 cDNA, creating the allele designated R26(floxneoWnt4. Wnt4 expression was activated during chondrogenesis using Col2a1-Cre transgenic mice that express Cre recombinase in differentiating chondrocytes. R26(floxneoWnt4; Col2a1-Cre double heterozygous mice exhibited a growth deficiency, beginning approximately 7 to 10 days after birth, that resulted in dwarfism. In addition, they also had craniofacial abnormalities, and delayed ossification of the lumbar vertebrae and pelvic bones. Histological analysis revealed a disruption in the organization of the growth plates and a delay in the onset of the primary and secondary ossification centers. Molecular studies showed that Wnt4 overexpression caused decreased proliferation and altered maturation of chondrocytes. In addition, R26(floxneoWnt4; Col2a1-Cre mice had decreased expression of vascular endothelial growth factor (VEGF. These studies demonstrate that Wnt4 overexpression leads to dwarfism in mice. The data indicate that Wnt4 levels must be regulated in chondrocytes for normal growth plate development and skeletogenesis. Decreased VEGF expression suggests that defects in vascularization may contribute to the dwarf phenotype.

  5. Conditional Expression of Wnt4 during Chondrogenesis Leads to Dwarfism in Mice

    Science.gov (United States)

    Lee, Hu-Hui; Behringer, Richard R.

    2007-01-01

    Wnts are expressed in the forming long bones, suggesting roles in skeletogenesis. To examine the action of Wnts in skeleton formation, we developed a genetic system to conditionally express Wnt4 in chondrogenic tissues of the mouse. A mouse Wnt4 cDNA was introduced into the ubiquitously expressed Rosa26 (R26) locus by gene targeting in embryonic stem (ES) cells. The expression of Wnt4 from the R26 locus was blocked by a neomycin selection cassette flanked by loxP sites (floxneo) that was positioned between the Rosa26 promoter and the Wnt4 cDNA, creating the allele designated R26floxneoWnt4. Wnt4 expression was activated during chondrogenesis using Col2a1-Cre transgenic mice that express Cre recombinase in differentiating chondrocytes. R26floxneoWnt4; Col2a1-Cre double heterozygous mice exhibited a growth deficiency, beginning approximately 7 to 10 days after birth, that resulted in dwarfism. In addition, they also had craniofacial abnormalities, and delayed ossification of the lumbar vertebrae and pelvic bones. Histological analysis revealed a disruption in the organization of the growth plates and a delay in the onset of the primary and secondary ossification centers. Molecular studies showed that Wnt4 overexpression caused decreased proliferation and altered maturation of chondrocytes. In addition, R26floxneoWnt4; Col2a1-Cre mice had decreased expression of vascular endothelial growth factor (VEGF). These studies demonstrate that Wnt4 overexpression leads to dwarfism in mice. The data indicate that Wnt4 levels must be regulated in chondrocytes for normal growth plate development and skeletogenesis. Decreased VEGF expression suggests that defects in vascularization may contribute to the dwarf phenotype. PMID:17505543

  6. Cellular demise and inflammatory microglial activation during beta-amyloid toxicity are governed by Wnt1 and canonical signaling pathways.

    Science.gov (United States)

    Chong, Zhao Zhong; Li, Faqi; Maiese, Kenneth

    2007-06-01

    Initially described as a modulator of embryogenesis for a number of organ systems, Wnt1 has recently been linked to the development of several neurodegenerative disorders, none being of greater significance than Alzheimer's disease. We therefore examined the ability of Wnt1 to oversee vital pathways responsible for cell survival during beta-amyloid (Abeta1-42) exposure. Here we show that Wnt1 is critical for protection in the SH-SY5Y neuronal cell line against genomic DNA degradation, membrane phosphatidylserine (PS) exposure, and microglial activation, since these neuroprotective attributes of Wnt1 are lost during gene silencing of Wnt1 protein expression. Intimately tied to Wnt1 protection is the presence and activation of Akt1. Pharmacological inhibition of the PI 3-K pathway or gene silencing of Akt1 expression can abrogate the protective capacity of Wnt1. Closely aligned with Wnt1 and Akt1 are the integrated canonical pathways of synthase kinase-3beta (GSK-3beta) and beta-catenin. Through Akt1 dependent pathways, Wnt1 phosphorylates GSK-3beta and maintains beta-catenin integrity to insure its translocation from the cytoplasm to the nucleus to block apoptosis. Our work outlines a highly novel role for Wnt1 and its integration with Akt1, GSK-3beta, and beta-catenin to foster neuronal cell survival and repress inflammatory microglial activation that can identify new avenues of therapy against neurodegenerative disorders.

  7. Non-canonical Wnt signaling through Wnt5a/b and a novel Wnt11 gene, Wnt11b, regulates cell migration during avian gastrulation

    OpenAIRE

    Hardy, Katharine M.; Garriock, Robert J.; Yatskievych, Tatiana A.; D'Agostino, Susan L.; Antin, Parker B.; Krieg, Paul A.

    2008-01-01

    Knowledge of the molecular mechanisms regulating cell ingression, epithelial-mesenchymal transition and migration movements during amniote gastrulation is steadily improving. In the frog and fish embryo, Wnt5 and Wnt11 ligands are expressed around the blastopore and play an important role in regulating cell movements associated with gastrulation. In the chicken embryo, although Wnt5a and Wnt5b are expressed in the primitive streak, the known Wnt11 gene is expressed in paraxial and intermediat...

  8. Inhibition of hypoxia inducible factor-1alpha by dihydroxyphenylethanol, a product from olive oil, blocks microsomal prostaglandin-E synthase-1/vascular endothelial growth factor expression and reduces tumor angiogenesis.

    Science.gov (United States)

    Terzuoli, Erika; Donnini, Sandra; Giachetti, Antonio; Iñiguez, Miguel A; Fresno, Manuel; Melillo, Giovanni; Ziche, Marina

    2010-08-15

    2-(3,4-dihydroxyphenil)-ethanol (DPE), a polyphenol present in olive oil, has been found to attenuate the growth of colon cancer cells, an effect presumably related to its anti-inflammatory activity. To further explore the effects of DPE on angiogenesis and tumor growth we investigated the in vivo efficacy of DPE in a HT-29 xenograft model and in vitro activities in colon cancer cells exposed to interleukin-1beta (IL-1beta) and prostaglandin E-2 (PGE-2). DPE (10 mg/kg/day for 14 days) inhibited tumor growth, reducing vessel lumina and blood perfusion to tumor, and diminished expression of hypoxia inducible factor-1alpha (HIF-1alpha), vascular endothelial growth factor (VEGF), and microsomal prostaglandin-E synthase-1 (mPGEs-1). In vitro, DPE (100 mumol/L) neither affected cell proliferation nor induced apoptosis in HT-29 and WiDr cells. DPE prevented the IL-1beta-mediated increase of mPGEs-1 expression and PGE-2 generation, as it did the silencing of HIF-1alpha. Moreover, DPE blocked mPGEs-1-dependent expression of VEGF and inhibited endothelial sprouting induced by tumor cells in a coculture system. PGE-2 triggers a feed-forward loop involving HIF-1alpha, which impinges on mPGEs-1 and VEGF expression, events prevented by DPE via extracellular signal-related kinase 1/2. The reduction of PGE-2 and VEGF levels, caused by DPE, was invariably associated with a marked decrease in HIF-1alpha expression and activity, independent of proteasome activity, indicating that the DPE effects on tumor growth and angiogenesis are dependent on the inhibition of HIF-1alpha translation. We show that the in vivo DPE antitumor effect is associated with anti-inflammatory and antiangiogenic activities resulting from the downregulation of the HIF-1alpha/mPGEs-1/VEGF axis.

  9. Wnt6, Wnt10a and Wnt10b inhibit adipogenesis and stimulate osteoblastogenesis through a β-catenin-dependent mechanism

    OpenAIRE

    Cawthorn, William P.; Bree, Adam J.; Yao, Yao; Du, Baowen; Hemati, Nahid; Martinez-Santibañez, Gabriel; MacDougald, Ormond A.

    2011-01-01

    Wnt10b is an established regulator of mesenchymal stem cell (MSC) fate that inhibits adipogenesis and stimulates osteoblastogenesis, thereby impacting bone mass in vivo. However, downstream mechanisms through which Wnt10b exerts these effects are poorly understood. Moreover, whether other endogenous Wnt ligands also modulate MSC fate remains to be fully addressed. In this study, we identify Wnt6 and Wnt10a as additional Wnt family members that, like Wnt10b, are downregulated during developmen...

  10. Wnt5a attenuates Wnt3a-induced alkaline phosphatase expression in dental follicle cells

    International Nuclear Information System (INIS)

    Sakisaka, Yukihiko; Tsuchiya, Masahiro; Nakamura, Takashi; Tamura, Masato; Shimauchi, Hidetoshi; Nemoto, Eiji

    2015-01-01

    Wnt signaling regulates multiple cellular events such as cell proliferation, differentiation, and apoptosis through β-catenin-dependent canonical and β-catenin-independent noncanonical pathways. Canonical Wnt/β-catenin signaling can promote the differentiation of dental follicle cells, putative progenitor cells for cementoblasts, osteoblasts, and periodontal ligament cells, toward a cementoblast/osteoblast phenotype during root formation, but little is known about the biological significance of noncanonical Wnt signaling in this process. We identified the expression of Wnt5a, a representative noncanonical Wnt ligand, in tooth root lining cells (i.e. precementoblasts/cementoblasts) and dental follicle cells during mouse tooth root development, as assessed by immunohistochemistry. Silencing expression of the Wnt5a gene in a dental follicle cell line resulted in enhancement of the Wnt3a (a representative canonical Wnt ligand)-mediated increase in alkaline phosphatase (ALP) expression. Conversely, treatment with recombinant Wnt5a inhibited the increase in ALP expression, suggesting that Wnt5a signaling functions as a negative regulator of canonical Wnt-mediated ALP expression of dental follicle cells. Wnt5a did not affect the nuclear translocation of β-catenin as well as β-catenin-mediated transcriptional activation of T-cell factor (Tcf) triggered by Wnt3a, suggesting that Wnt5a inhibits the downstream part of the β-catenin-Tcf pathway. These findings suggest the existence of a feedback mechanism between canonical and noncanonical Wnt signaling during the differentiation of dental follicle cells. - Highlights: • Dental follicle cells express Wnt5a during tooth root development. • Silencing of Wnt5a enhances Wnt3a-mediated ALP expression of dental follicle cells. • Conversely, treatment with rWnt5a inhibited the increase in ALP expression. • Wnt5a functions as a negative regulator of Wnt3a-mediated ALP expression

  11. Wnt5a attenuates Wnt3a-induced alkaline phosphatase expression in dental follicle cells

    Energy Technology Data Exchange (ETDEWEB)

    Sakisaka, Yukihiko [Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Tsuchiya, Masahiro [Department of Oral Diagnosis, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Tohoku Fukushi University, Sendai 989-3201 (Japan); Nakamura, Takashi [Department of Pediatric Dentistry, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Liason Center for Innovative Dentistry, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Tamura, Masato [Department of Biochemistry and Molecular Biology, Hokkaido University Graduate School of Dentistry, Sapporo 060-8586 (Japan); Shimauchi, Hidetoshi [Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Nemoto, Eiji, E-mail: e-nemoto@dent.tohoku.ac.jp [Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan)

    2015-08-01

    Wnt signaling regulates multiple cellular events such as cell proliferation, differentiation, and apoptosis through β-catenin-dependent canonical and β-catenin-independent noncanonical pathways. Canonical Wnt/β-catenin signaling can promote the differentiation of dental follicle cells, putative progenitor cells for cementoblasts, osteoblasts, and periodontal ligament cells, toward a cementoblast/osteoblast phenotype during root formation, but little is known about the biological significance of noncanonical Wnt signaling in this process. We identified the expression of Wnt5a, a representative noncanonical Wnt ligand, in tooth root lining cells (i.e. precementoblasts/cementoblasts) and dental follicle cells during mouse tooth root development, as assessed by immunohistochemistry. Silencing expression of the Wnt5a gene in a dental follicle cell line resulted in enhancement of the Wnt3a (a representative canonical Wnt ligand)-mediated increase in alkaline phosphatase (ALP) expression. Conversely, treatment with recombinant Wnt5a inhibited the increase in ALP expression, suggesting that Wnt5a signaling functions as a negative regulator of canonical Wnt-mediated ALP expression of dental follicle cells. Wnt5a did not affect the nuclear translocation of β-catenin as well as β-catenin-mediated transcriptional activation of T-cell factor (Tcf) triggered by Wnt3a, suggesting that Wnt5a inhibits the downstream part of the β-catenin-Tcf pathway. These findings suggest the existence of a feedback mechanism between canonical and noncanonical Wnt signaling during the differentiation of dental follicle cells. - Highlights: • Dental follicle cells express Wnt5a during tooth root development. • Silencing of Wnt5a enhances Wnt3a-mediated ALP expression of dental follicle cells. • Conversely, treatment with rWnt5a inhibited the increase in ALP expression. • Wnt5a functions as a negative regulator of Wnt3a-mediated ALP expression.

  12. Wnt Signalling Promotes Actin Dynamics during Axon Remodelling through the Actin-Binding Protein Eps8.

    Directory of Open Access Journals (Sweden)

    Eleanna Stamatakou

    Full Text Available Upon arrival at their synaptic targets, axons slow down their growth and extensively remodel before the assembly of presynaptic boutons. Wnt proteins are target-derived secreted factors that promote axonal remodelling and synaptic assembly. In the developing spinal cord, Wnts secreted by motor neurons promote axonal remodelling of NT-3 responsive dorsal root ganglia neurons. Axon remodelling induced by Wnts is characterised by growth cone pausing and enlargement, processes that depend on the re-organisation of microtubules. However, the contribution of the actin cytoskeleton has remained unexplored. Here, we demonstrate that Wnt3a regulates the actin cytoskeleton by rapidly inducing F-actin accumulation in growth cones from rodent DRG neurons through the scaffold protein Dishevelled-1 (Dvl1 and the serine-threonine kinase Gsk3β. Importantly, these changes in actin cytoskeleton occurs before enlargement of the growth cones is evident. Time-lapse imaging shows that Wnt3a increases lamellar protrusion and filopodia velocity. In addition, pharmacological inhibition of actin assembly demonstrates that Wnt3a increases actin dynamics. Through a yeast-two hybrid screen, we identified the actin-binding protein Eps8 as a direct interactor of Dvl1, a scaffold protein crucial for the Wnt signalling pathway. Gain of function of Eps8 mimics Wnt-mediated axon remodelling, whereas Eps8 silencing blocks the axon remodelling activity of Wnt3a. Importantly, blockade of the Dvl1-Eps8 interaction completely abolishes Wnt3a-mediated axonal remodelling. These findings demonstrate a novel role for Wnt-Dvl1 signalling through Eps8 in the regulation of axonal remodeling.

  13. Wnt signaling: Ig-norrin the dogma.

    Science.gov (United States)

    Clevers, Hans

    2004-06-08

    Secreted Wnt proteins trigger the intracellular Wnt signaling cascade upon engagement of dedicated Frizzled-Lrp receptor complexes. Unexpectedly, a non-Wnt ligand for this receptor complex has now been discovered. This novel ligand, Norrin, is mutated in the hereditary ocular Norrie syndrome. Copyright 2004 Elsevier Ltd.

  14. Wnt Signaling in Cancer Stem Cell Biology

    NARCIS (Netherlands)

    de Sousa E Melo, Felipe; Vermeulen, Louis

    2016-01-01

    Aberrant regulation of Wnt signaling is a common theme seen across many tumor types. Decades of research have unraveled the epigenetic and genetic alterations that result in elevated Wnt pathway activity. More recently, it has become apparent that Wnt signaling levels identify stem-like tumor cells

  15. Hypoxia-Induced Signaling Promotes Prostate Cancer Progression: Exosomes Role as Messenger of Hypoxic Response in Tumor Microenvironment

    Science.gov (United States)

    Deep, Gagan; Panigrahi, Gati K.

    2017-01-01

    Prostate cancer (PCA) is the leading malignancy in men and the second leading cause of cancer-related deaths. Hypoxia (low O2 condition) is considered an early event in prostate carcinogenesis associated with an aggressive phenotype. In fact, clinically, hypoxia and hypoxia-related biomarkers are associated with treatment failure and disease progression. Hypoxia-inducible factor 1 (HIF-1) is the key factor that is activated under hypoxia, and mediates adaptation of cells to hypoxic conditions through regulating the expression of genes associated with angiogenesis, epithelial-to-mesenchymal transition (EMT), metastasis, survival, proliferation, metabolism, stemness, hormone-refractory progression, and therapeutic resistance. Besides HIF-1, several other signaling pathways including PI3K/Akt/mTOR, NADPH oxidase (NOX), Wnt/β-catenin, and Hedgehog are activated in cancer cells under hypoxic conditions, and also contribute in hypoxia-induced biological effects in HIF-1-dependent and -independent manners. Hypoxic cancer cells cause extensive changes in the tumor microenvironment both local and distant, and recent studies have provided ample evidence supporting the crucial role of nanosized vesicles “exosomes” in mediating hypoxia-induced tumor microenvironment remodeling. Exosomes’ role has been reported in hypoxia-induced angiogenesis, stemness, activation of cancer-associated fibroblasts (CAFs), and EMT. Together, existing literature suggests that hypoxia plays a predominant role in PCA growth and progression, and PCA could be effectively prevented and treated via targeting hypoxia/hypoxia-related signaling pathways. PMID:27279239

  16. Fresh WNT into the regulation of mitosis.

    Science.gov (United States)

    Stolz, Ailine; Bastians, Holger

    2015-01-01

    Canonical Wnt signaling triggering β-catenin-dependent gene expression contributes to cell cycle progression, in particular at the G1/S transition. Recently, however, it became clear that the cell cycle can also feed back on Wnt signaling at the G2/M transition. This is illustrated by the fact that mitosis-specific cyclin-dependent kinases can phosphorylate the Wnt co-receptor LRP6 to prime the pathway for incoming Wnt signals when cells enter mitosis. In addition, there is accumulating evidence that various Wnt pathway components might exert additional, Wnt-independent functions that are important for proper regulation of mitosis. The importance of Wnt pathways during mitosis was most recently enforced by the discovery of Wnt signaling contributing to the stabilization of proteins other than β-catenin, specifically at G2/M and during mitosis. This Wnt-mediated stabilization of proteins, now referred to as Wnt/STOP, might on one hand contribute to maintaining a critical cell size required for cell division and, on the other hand, for the faithful execution of mitosis itself. In fact, most recently we have shown that Wnt/STOP is required for ensuring proper microtubule dynamics within mitotic spindles, which is pivotal for accurate chromosome segregation and for the maintenance of euploidy.

  17. Canonical Wnt signaling in diabetic retinopathy.

    Science.gov (United States)

    Chen, Qian; Ma, Jian-Xing

    2017-10-01

    Diabetic retinopathy (DR) is a common eye complication of diabetes, and the pathogenic mechanism of DR is still under investigation. The canonical Wnt signaling pathway is an evolutionarily conserved pathway that plays fundamental roles in embryogenesis and adult tissue homeostasis. Wnt signaling regulates expression of multiple genes that control retinal development and eye organogenesis, and dysregulated Wnt signaling plays pathophysiological roles in many ocular diseases, including DR. This review highlights recent progress in studies of Wnt signaling in DR. We discuss Wnt signaling regulation in the retina and dysregulation of Wnt signaling associated with ocular diseases with an emphasis on DR. We also discuss the therapeutic potential of modulating Wnt signaling in DR. Continued studies in this field will advance our current understanding on DR and contribute to the development of new treatments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Wnt5a Signaling in Cancer

    Directory of Open Access Journals (Sweden)

    Marwa S. Asem

    2016-08-01

    Full Text Available Wnt5a is involved in activating several non-canonical WNT signaling pathways, through binding to different members of the Frizzled- and Ror-family receptors. Wnt5a signaling is critical for regulating normal developmental processes, including proliferation, differentiation, migration, adhesion and polarity. However, the aberrant activation or inhibition of Wnt5a signaling is emerging as an important event in cancer progression, exerting both oncogenic and tumor suppressive effects. Recent studies show the involvement of Wnt5a in regulating cancer cell invasion, metastasis, metabolism and inflammation. In this article, we review findings regarding the molecular mechanisms and roles of Wnt5a signaling in various cancer types, and highlight Wnt5a in ovarian cancer.

  19. Wnt isoform-specific interactions with coreceptor specify inhibition or potentiation of signaling by LRP6 antibodies.

    Directory of Open Access Journals (Sweden)

    Yan Gong

    Full Text Available β-Catenin-dependent Wnt signaling is initiated as Wnt binds to both the receptor FZD and coreceptor LRP5/6, which then assembles a multimeric complex at the cytoplasmic membrane face to recruit and inactivate the kinase GSK3. The large number and sequence diversity of Wnt isoforms suggest the possibility of domain-specific ligand-coreceptor interactions, and distinct binding sites on LRP6 for Wnt3a and Wnt9b have recently been identified in vitro. Whether mechanistically different interactions between Wnts and coreceptors might mediate signaling remains to be determined. It is also not clear whether coreceptor homodimerization induced extracellularly can activate Wnt signaling, as is the case for receptor tyrosine kinases. We generated monoclonal antibodies against LRP6 with the unexpected ability to inhibit signaling by some Wnt isoforms and potentiate signaling by other isoforms. In cell culture, two antibodies characterized further show reciprocal activities on most Wnts, with one antibody antagonizing and the other potentiating. We demonstrate that these antibodies bind to different regions of LRP6 protein, and inhibition of signaling results from blocking Wnt binding. Antibody-mediated dimerization of LRP6 can potentiate signaling only when a Wnt isoform is also able to bind the complex, presumably recruiting FZD. Endogenous autocrine Wnt signaling in different tumor cell lines can be either antagonized or enhanced by the LRP6 antibodies, indicating expression of different Wnt isoforms. As anticipated from the roles of Wnt signaling in cancer and bone development, antibody activities can also be observed in mice for inhibition of tumor growth and in organ culture for enhancement of bone mineral density. Collectively, our results indicate that separate binding sites for different subsets of Wnt isoforms determine the inhibition or potentiation of signaling conferred by LRP6 antibodies. This complexity of coreceptor-ligand interactions may

  20. Migraine induced by hypoxia

    DEFF Research Database (Denmark)

    Arngrim, Nanna; Schytz, Henrik Winther; Britze, Josefine

    2016-01-01

    in the visual cortex were measured by proton magnetic resonance spectroscopy. The circumference of cranial arteries was measured by 3 T high-resolution magnetic resonance angiography. Hypoxia induced migraine-like attacks in eight patients compared to one patient after sham (P = 0.039), aura in three...... and possible aura in 4 of 15 patients. Hypoxia did not change glutamate concentration in the visual cortex compared to sham, but increased lactate concentration (P = 0.028) and circumference of the cranial arteries (P ... suggests that hypoxia may provoke migraine headache and aura symptoms in some patients. The mechanisms behind the migraine-inducing effect of hypoxia should be further investigated....

  1. Hypoxia and hypoxia mimetics decrease aquaporin 5 (AQP5 expression through both hypoxia inducible factor-1α and proteasome-mediated pathways.

    Directory of Open Access Journals (Sweden)

    Jitesh D Kawedia

    Full Text Available The alveolar epithelium plays a central role in gas exchange and fluid transport, and is therefore critical for normal lung function. Since the bulk of water flux across this epithelium depends on the membrane water channel Aquaporin 5 (AQP5, we asked whether hypoxia had any effect on AQP5 expression. We show that hypoxia causes a significant (70% decrease in AQP5 expression in the lungs of mice exposed to hypoxia. Hypoxia and the hypoxia mimetic, cobalt, also caused similar decreases in AQP5 mRNA and protein expression in the mouse lung epithelial cell line MLE-12. The action of hypoxia and cobalt on AQP5 transcription was demonstrated by directly quantifying heternonuclear RNA by real-time PCR. Dominant negative mutants of Hypoxia Inducible Factor (HIF-1α and HIF-1α siRNA blocked the action of cobalt, showing that HIF-1α is a key component in this mechanism. The proteasome inhibitors, lactacystin or proteasome inhibitor-III completely abolished the effect of hypoxia and cobalt both at the protein and mRNA level indicating that the proteasome pathway is probably involved not only for the stability of HIF-1α protein, but for the stability of unidentified transcription factors that regulate AQP5 transcription. These studies reveal a potentially important physiological mechanism linking hypoxic stress and membrane water channels.

  2. Hypoxia and Hypoxia Mimetics Decrease Aquaporin 5 (AQP5) Expression through Both Hypoxia Inducible Factor-1α and Proteasome-Mediated Pathways

    Science.gov (United States)

    Kawedia, Jitesh D.; Yang, Fan; Sartor, Maureen A.; Gozal, David; Czyzyk-Krzeska, Maria; Menon, Anil G.

    2013-01-01

    The alveolar epithelium plays a central role in gas exchange and fluid transport, and is therefore critical for normal lung function. Since the bulk of water flux across this epithelium depends on the membrane water channel Aquaporin 5 (AQP5), we asked whether hypoxia had any effect on AQP5 expression. We show that hypoxia causes a significant (70%) decrease in AQP5 expression in the lungs of mice exposed to hypoxia. Hypoxia and the hypoxia mimetic, cobalt, also caused similar decreases in AQP5 mRNA and protein expression in the mouse lung epithelial cell line MLE-12. The action of hypoxia and cobalt on AQP5 transcription was demonstrated by directly quantifying heternonuclear RNA by real-time PCR. Dominant negative mutants of Hypoxia Inducible Factor (HIF-1α) and HIF-1α siRNA blocked the action of cobalt, showing that HIF-1α is a key component in this mechanism. The proteasome inhibitors, lactacystin or proteasome inhibitor-III completely abolished the effect of hypoxia and cobalt both at the protein and mRNA level indicating that the proteasome pathway is probably involved not only for the stability of HIF-1α protein, but for the stability of unidentified transcription factors that regulate AQP5 transcription. These studies reveal a potentially important physiological mechanism linking hypoxic stress and membrane water channels. PMID:23469202

  3. Selective vulnerability in brain hypoxia

    DEFF Research Database (Denmark)

    Cervos-Navarro, J.; Diemer, Nils Henrik

    1991-01-01

    Neuropathology, selective vulnerability, brain hypoxia, vascular factors, excitotoxicity, ion homeostasis......Neuropathology, selective vulnerability, brain hypoxia, vascular factors, excitotoxicity, ion homeostasis...

  4. Wnt Signaling in Kidney Development and Disease.

    Science.gov (United States)

    Wang, Yongping; Zhou, Chengji J; Liu, Youhua

    2018-01-01

    Wnt signal cascade is an evolutionarily conserved, developmental pathway that regulates embryogenesis, injury repair, and pathogenesis of human diseases. It is well established that Wnt ligands transmit their signal via canonical, β-catenin-dependent and noncanonical, β-catenin-independent mechanisms. Mounting evidence has revealed that Wnt signaling plays a key role in controlling early nephrogenesis and is implicated in the development of various kidney disorders. Dysregulations of Wnt expression cause a variety of developmental abnormalities and human diseases, such as congenital anomalies of the kidney and urinary tract, cystic kidney, and renal carcinoma. Multiple Wnt ligands, their receptors, and transcriptional targets are upregulated during nephron formation, which is crucial for mediating the reciprocal interaction between primordial tissues of ureteric bud and metanephric mesenchyme. Renal cysts are also associated with disrupted Wnt signaling. In addition, Wnt components are important players in renal tumorigenesis. Activation of Wnt/β-catenin is instrumental for tubular repair and regeneration after acute kidney injury. However, sustained activation of this signal cascade is linked to chronic kidney diseases and renal fibrosis in patients and experimental animal models. Mechanistically, Wnt signaling controls a diverse array of biologic processes, such as cell cycle progression, cell polarity and migration, cilia biology, and activation of renin-angiotensin system. In this chapter, we have reviewed recent findings that implicate Wnt signaling in kidney development and diseases. Targeting this signaling may hold promise for future treatment of kidney disorders in patients. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Wnt-5a and Wnt-4 Regulates Cell Growth in C57MG Mammary Epithelial Cells

    National Research Council Canada - National Science Library

    Olson, Daniel

    1998-01-01

    .... That is, it is important ultimately to understand whether the inappropriate down regulation of certain wnt-genes that are spatially-temporally expressed in developing mammary glands, such as wnt-5a...

  6. Heterotrimeric G protein-dependent WNT-5A signaling to ERK1/2 mediates distinct aspects of microglia proinflammatory transformation

    Directory of Open Access Journals (Sweden)

    Halleskog Carina

    2012-05-01

    Thus, WNT-5A-induced and G protein-dependent signaling to ERK1/2 is important for the regulation of proinflammatory responses in mouse primary microglia cells. We show for the first time that WNT-5A/G protein signaling mediates physiologically important processes in primary mammalian cells with natural receptor and G protein stochiometry. Consequently, WNT-5A emerges as an important means of astrocyte-microglia communication and we, therefore, suggest WNT-5A as a new player in neuroinflammatory conditions, such as neurodegenerative disease, hypoxia, stroke, injury and infection.

  7. Wnt and the Wnt signaling pathway in bone development and disease

    Science.gov (United States)

    Wang, Yiping; Li, Yi-Ping; Paulson, Christie; Shao, Jian-Zhong; Zhang, Xiaoling; Wu, Mengrui; Chen, Wei

    2014-01-01

    Wnt signaling affects both bone modeling, which occurs during development, and bone remodeling, which is a lifelong process involving tissue renewal. Wnt signals are especially known to affect the differentiation of osteoblasts. In this review, we summarize recent advances in understanding the mechanisms of Wnt signaling, which is divided into two major branches: the canonical pathway and the noncanonical pathway. The canonical pathway is also called the Wnt/β-catenin pathway. There are two major noncanonical pathways: the Wnt-planar cell polarity pathway (Wnt-PCP pathway) and the Wnt-calcium pathway (Wnt-Ca2+ pathway). This review also discusses how Wnt ligands, receptors, intracellular effectors, transcription factors, and antagonists affect both the bone modeling and bone remodeling processes. We also review the role of Wnt ligands, receptors, intracellular effectors, transcription factors, and antagonists in bone as demonstrated in mouse models. Disrupted Wnt signaling is linked to several bone diseases, including osteoporosis, van Buchem disease, and sclerosteosis. Studying the mechanism of Wnt signaling and its interactions with other signaling pathways in bone will provide potential therapeutic targets to treat these bone diseases. PMID:24389191

  8. Wnt signaling requires retromer-dependent recycling of MIG-14/Wntless in Wnt-producing cells.

    NARCIS (Netherlands)

    Yang, P.T.; Lorenowicz, M.J.; Silhankova, M.; Coudreuse, D.Y.M.; Betist, M.C.; Korswagen, H.C.

    2008-01-01

    Wnt proteins are secreted signaling molecules that play a central role in development and adult tissue homeostasis. We have previously shown that Wnt signaling requires retromer function in Wnt-producing cells. The retromer is a multiprotein complex that mediates endosome-to-Golgi transport of

  9. Wnt signaling and polarity in freshwater sponges.

    Science.gov (United States)

    Windsor Reid, Pamela J; Matveev, Eugueni; McClymont, Alexandra; Posfai, Dora; Hill, April L; Leys, Sally P

    2018-02-02

    The Wnt signaling pathway is uniquely metazoan and used in many processes during development, including the formation of polarity and body axes. In sponges, one of the earliest diverging animal groups, Wnt pathway genes have diverse expression patterns in different groups including along the anterior-posterior axis of two sponge larvae, and in the osculum and ostia of others. We studied the function of Wnt signaling and body polarity formation through expression, knockdown, and larval manipulation in several freshwater sponge species. Sponge Wnts fall into sponge-specific and sponge-class specific subfamilies of Wnt proteins. Notably Wnt genes were not found in transcriptomes of the glass sponge Aphrocallistes vastus. Wnt and its signaling genes were expressed in archaeocytes of the mesohyl throughout developing freshwater sponges. Osculum formation was enhanced by GSK3 knockdown, and Wnt antagonists inhibited both osculum development and regeneration. Using dye tracking we found that the posterior poles of freshwater sponge larvae give rise to tissue that will form the osculum following metamorphosis. Together the data indicate that while components of canonical Wnt signaling may be used in development and maintenance of osculum tissue, it is likely that Wnt signaling itself occurs between individual cells rather than whole tissues or structures in freshwater sponges.

  10. Chemical Modulation of WNT Signaling in Cancer.

    Science.gov (United States)

    Zhang, Li-Shu; Lum, Lawrence

    2018-01-01

    Genetically based observations stemming from defects in development and in regeneration form the foundation of our understanding regarding how the secreted WNT proteins control coordinated cell fate decision-making in adult tissues. At the same time, our anticipation of potential benefits and unwanted toxicities associated with candidate anticancer agents targeting WNT signal transduction are also reliant upon this blueprint of WNT-associated physiology. Despite the long established role of WNT signaling in cancer, the emergence of WNT signaling as a suppressor of immunological attack in melanoma reveals an unanticipated anticancer potential in targeting WNT signaling. Here we review the literature associated with WNT signaling in cancer and discuss potential challenges that may be associated with the chemical attack of this important cellular process in achieving therapeutic goals. Although a number of small molecules targeting WNT signaling are introduced here, we center our discussion on antagonists of the WNT acyltransferase porcupine (PORCN) given the recent entry of two candidate molecules in clinical testing. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Wnt-1 Signaling in Mammary Carcinogenesis

    Science.gov (United States)

    2000-04-01

    and the notochord (4), Wnt-5A/LRP6 or LRP6 (higher doses) alone induced trunk axis duplication with muscle and neural tissues but lacking head or the... notochord (Fig. lb). It remains unclear whether this is due to quantitative or qualitative differences between Wnt-5a/LRP6 and Wnt-5a/hFz5 co...2 ng) or Wnt-5a (20 pg) plus LRP6 (100 pg) induced trunk axis duplication lacking head and the notochord . Top: the whole embryo phenotype at stage 40

  12. Pharmacologic Activation of Wnt Signaling by Lithium Normalizes Retinal Vasculature in a Murine Model of Familial Exudative Vitreoretinopathy.

    Science.gov (United States)

    Wang, Zhongxiao; Liu, Chi-Hsiu; Sun, Ye; Gong, Yan; Favazza, Tara L; Morss, Peyton C; Saba, Nicholas J; Fredrick, Thomas W; He, Xi; Akula, James D; Chen, Jing

    2016-10-01

    Familial exudative vitreoretinopathy (FEVR) is characterized by delayed retinal vascular development, which promotes hypoxia-induced pathologic vessels. In severe cases FEVR may lead to retinal detachment and visual impairment. Genetic studies linked FEVR with mutations in Wnt signaling ligand or receptors, including low-density lipoprotein receptor-related protein 5 (LRP5) gene. Here, we investigated ocular pathologies in a Lrp5 knockout (Lrp5(-/-)) mouse model of FEVR and explored whether treatment with a pharmacologic Wnt activator lithium could bypass the genetic defects, thereby protecting against eye pathologies. Lrp5(-/-) mice displayed significantly delayed retinal vascular development, absence of deep layer retinal vessels, leading to increased levels of vascular endothelial growth factor and subsequent pathologic glomeruloid vessels, as well as decreased inner retinal visual function. Lithium treatment in Lrp5(-/-) mice significantly restored the delayed development of retinal vasculature and the intralaminar capillary networks, suppressed formation of pathologic glomeruloid structures, and promoted hyaloid vessel regression. Moreover, lithium treatment partially rescued inner-retinal visual function and increased retinal thickness. These protective effects of lithium were largely mediated through restoration of canonical Wnt signaling in Lrp5(-/-) retina. Lithium treatment also substantially increased vascular tubular formation in LRP5-deficient endothelial cells. These findings suggest that pharmacologic activation of Wnt signaling may help treat ocular pathologies in FEVR and potentially other defective Wnt signaling-related diseases. Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  13. Genetic Screening of WNT4 and WNT5B in Two Populations with Deviating Bone Mineral Densities

    DEFF Research Database (Denmark)

    Hendrickx, Gretl; Boudin, Eveline; Steenackers, Ellen

    2017-01-01

    A role for WNT4 and WNT5B in bone metabolism was indicated by genome-wide association studies (GWAS) and a Wnt4 knockout mouse model. The aim of this study was therefore to replicate and further investigate the causality between genetic variation in WNT4 and WNT5B and deviating bone mineral density...... (BMD) values. A WNT4 and WNT5B mutation screening was performed in patients with craniotubular hyperostosis using Sanger sequencing. Here, no putative causal mutations were detected. Moreover, a high and low BMD cohort was selected from the Odense Androgen Study population for re-sequencing. In WNT4 we...

  14. Jagged1 is the pathological link between Wnt and Notch pathways in colorectal cancer.

    Science.gov (United States)

    Rodilla, Verónica; Villanueva, Alberto; Obrador-Hevia, Antonia; Robert-Moreno, Alex; Fernández-Majada, Vanessa; Grilli, Andrea; López-Bigas, Nuria; Bellora, Nicolás; Albà, M Mar; Torres, Ferran; Duñach, Mireia; Sanjuan, Xavier; Gonzalez, Sara; Gridley, Thomas; Capella, Gabriel; Bigas, Anna; Espinosa, Lluís

    2009-04-14

    Notch has been linked to beta-catenin-dependent tumorigenesis; however, the mechanisms leading to Notch activation and the contribution of the Notch pathway to colorectal cancer is not yet understood. By microarray analysis, we have identified a group of genes downstream of Wnt/beta-catenin (down-regulated when blocking Wnt/beta-catenin) that are directly regulated by Notch (repressed by gamma-secretase inhibitors and up-regulated by active Notch1 in the absence of beta-catenin signaling). We demonstrate that Notch is downstream of Wnt in colorectal cancer cells through beta-catenin-mediated transcriptional activation of the Notch-ligand Jagged1. Consistently, expression of activated Notch1 partially reverts the effects of blocking Wnt/beta-catenin pathway in tumors implanted s.c. in nude mice. Crossing APC(Min/+) with Jagged1(+/Delta) mice is sufficient to significantly reduce the size of the polyps arising in the APC mutant background indicating that Notch is an essential modulator of tumorigenesis induced by nuclear beta-catenin. We show that this mechanism is operating in human tumors from Familial Adenomatous Polyposis patients. We conclude that Notch activation, accomplished by beta-catenin-mediated up-regulation of Jagged1, is required for tumorigenesis in the intestine. The Notch-specific genetic signature is sufficient to block differentiation and promote vasculogenesis in tumors whereas proliferation depends on both pathways.

  15. WNT-mediated Modulation of Bone Metabolism: Implications for WNT Targeting to Treat Extraskeletal Disorders.

    Science.gov (United States)

    Bullock, Whitney A; Robling, Alexander G

    2017-10-01

    The WNT-signaling pathway is involved in cellular and tissue functions that control such diverse processes as body axis patterning, cellular proliferation, differentiation, and life span. The long list of molecules that can participate or modify WNT signaling makes this pathway one of the most complex in cell biology. In bone tissues, WNT signaling is required for proper skeletal development, and human mutations in various components of the cascade revealed insights into pharmacologic targeting that can be harnessed to improve skeletal health. In particular, mutations in genes that code for the WNT-signaling inhibitor sclerostin or the WNT coreceptor lipoprotein receptor-related protein 5 have highlighted the potential therapeutic value of recapitulating those effects in patients with low bone mass. A constant challenge in this area is selectively modifying WNT components in the tissue of interest, as WNT has manifold effects in nearly every tissue.

  16. Wnt/β-catenin signaling is required for distraction osteogenesis in rats.

    Science.gov (United States)

    Wang, Xuemei; Luo, En; Bi, Ruiye; Ye, Bin; Hu, Jing; Zou, Shujuan

    2018-01-01

    The Wnt signaling pathway plays crucial roles in embryonic skeletal development and postnatal bone regeneration. However, mechanisms of Wnt signaling functioning in distraction osteogenesis (DO) haven't been well characterized. We established a DO model using Sprague-Dawley rat tibia. And a Wnt signaling blocking agent, recombinant rat Dickkopf-related protein 1 (rrDkk1), was locally applied in the distracted gap to study the role of Wnt signaling during DO process. Animals in the experimental group received rrDkk1 injections (dose = 25 μg/kg) once daily during distraction period and every third day during consolidation stage (n = 48). Animals in the control group received saline under the same injection strategy (n = 48). Animals at different time points during DO process (1, 3, 6, 12 days after distraction, 10 days and 6 weeks after consolidation) were killed and tissues in the distraction region were harvested for radiography, dual energy X-ray absorptiometry, micro-computed tomography (micro-CT), and histological analyses. Most Wnt ligands, cofactors, receptors, and antagonists were widely expressed in the distraction callus and were significantly upregulated during DO process. After rrDkk1 administration, the majority of these factors were downregulated at the mRNA level, except sFRP and GSK-3β. At the protein level, both β-catenin and Lef-1 were also suppressed by rrDkk1. In the long term, restricted bone healing was observed in the distracted callus in the rrDkk1 injection group. These findings were confirmed by histological and micro-CT analyses. Our findings suggest that Wnt signaling participates in the process of DO, and clinical therapeutic approaches of DO may do well to avoid Wnt pathway suppression.

  17. Characterization of wise protein and its molecular mechanism to interact with both Wnt and BMP signals.

    Science.gov (United States)

    Lintern, Katherine B; Guidato, Sonia; Rowe, Alison; Saldanha, José W; Itasaki, Nobue

    2009-08-21

    Cross-talk of BMP and Wnt signaling pathways has been implicated in many aspects of biological events during embryogenesis and in adulthood. A secreted protein Wise and its orthologs (Sostdc1, USAG-1, and Ectodin) have been shown to modulate Wnt signaling and also inhibit BMP signals. Modulation of Wnt signaling activity by Wise is brought about by an interaction with the Wnt co-receptor LRP6, whereas BMP inhibition is by binding to BMP ligands. Here we have investigated the mode of action of Wise on Wnt and BMP signals. It was found that Wise binds LRP6 through one of three loops formed by the cystine knot. The Wise deletion construct lacking the LRP6-interacting loop domain nevertheless binds BMP4 and inhibits BMP signals. Moreover, BMP4 does not interfere with Wise-LRP6 binding, suggesting separate domains for the physical interaction. Functional assays also show that the ability of Wise to block Wnt1 activity through LRP6 is not impeded by BMP4. In contrast, the ability of Wise to inhibit BMP4 is prevented by additional LRP6, implying a preference of Wise in binding LRP6 over BMP4. In addition to the interaction of Wise with BMP4 and LRP6, the molecular characteristics of Wise, such as glycosylation and association with heparan sulfate proteoglycans on the cell surface, are suggested. This study helps to understand the multiple functions of Wise at the molecular level and suggests a possible role for Wise in balancing Wnt and BMP signals.

  18. A positive role of cadherin in Wnt/β-catenin signalling during epithelial-mesenchymal transition.

    Directory of Open Access Journals (Sweden)

    Sara Howard

    Full Text Available The Wnt/β-catenin signalling pathway shares a key component, β-catenin, with the cadherin-based adhesion system. The signalling function of β-catenin is conferred by a soluble cytoplasmic pool that is unstable in the absence of a Wnt signal, whilst the adhesion function is based on a cadherin-bound, stable pool at the membrane. The cadherin complex is dynamic, allowing for cell-cell rearrangements such as epithelial-mesenchymal transition (EMT, where the complex turns over through internalisation. Potential interplay between the two pools remains poorly understood, but cadherins are generally considered negative regulators of Wnt signalling because they sequester cytoplasmic β-catenin. Here we explore how cellular changes at EMT affect the signalling capacity of β-catenin using two models of EMT: hepatocyte growth factor (HGF treatment of MDCK cells, and gastrulation in embryonic development. We show that EMT not only provides a pool of signalling-competent β-catenin following internalisation of cadherin, but also significantly facilitates activation of the Wnt pathway in response to both Wnt signals and exogenous β-catenin. We further demonstrate that availability of β-catenin in the cytoplasm does not necessarily correlate with Wnt/β-catenin pathway activity, since blocking endocytosis or depleting endogenous cadherin abolishes pathway activation despite the presence of β-catenin in the cytoplasm. Lastly we present data suggesting that cadherins are required for augmented activation of the Wnt/β-catenin pathway in vivo. This suggests that cadherins play a crucial role in β-catenin-dependent transcription.

  19. Wnt secretion and signaling in Caenorhabditis elegans

    NARCIS (Netherlands)

    Yang, P.T.

    2008-01-01

    Wnt proteins are a highly conserved family of signaling molecules that play a central role during development and in adult tissue homeostasis. Wnt proteins regulate a variety of biological processes, ranging from cell proliferation and cell fate determination to cell migration, axon guidance and

  20. WNT4 signaling in female gonadal development.

    Science.gov (United States)

    Pellegrino, Miriam; Maiorino, Raffaella; Schonauer, Sergio

    2010-06-01

    WNT4 signaling pathways represent an important step in the multi-faceted process of mammalian gonadal differentiation and the development of internal genitalia. WNT4 protein controls the cytoplasmatic stability of specific transcriptional coactivator beta catenin during both embriogenesis and adult homeostasis. The biological significance of WNT4 consists in determining the final female reproductive system, inhibiting Wolff ducts' differentiation, male steroidogenesis and vascular cell migration. An overview of WNT4 cellular mechanisms is given in order to understand its critical role in the genesis of various human diseases such as congenital malformations and gynecological disorders like polycystic ovary syndrome (PCOS). The final discussion focusses on several possible therapeutic uses of Wnt4 both during pregnancy in order to correct the genetic loss of function of the protein and during adulthood in order to normalize fertility in PCOS-affected females planning pregnancy.

  1. Roles of Wnt/β-catenin signaling in epithelial differentiation of mesenchymal stem cells

    International Nuclear Information System (INIS)

    Wang, Yajing; Sun, Zhaorui; Qiu, Xuefeng; Li, Yan; Qin, Jizheng; Han, Xiaodong

    2009-01-01

    Bone marrow-derived mesenchymal stem cells (MSCs) have been demonstrated to be able to differentiate into epithelial lineage, but the precise mechanisms controlling this process are unclear. Our aim is to explore the roles of Wnt/β-catenin in the epithelial differentiation of MSCs. Using indirect co-culture of rat MSCs with rat airway epithelial cells (RTE), MSCs expressed several airway epithelial markers (cytokeratin 18, tight junction protein occudin, cystic fibrosis transmembrance regulator). The protein levels of some important members in Wnt/β-catenin signaling were determined, suggested down-regulation of Wnt/β-catenin with epithelial differentiation of MSCs. Furthermore, Wnt3α can inhibit the epithelial differentiation of MSCs. A loss of β-catenin induced by Dickkopf-1 can enhance MSCs differentiation into epithelial cells. Lithium chloride transiently activated β-catenin expression and subsequently decreased β-catenin level and at last inhibited MSCs to differentiate into airway epithelium. Taken together, our study indicated that RTE cells can trigger epithelial differentiation of MSCs. Blocking Wnt/β-catenin signaling may promote MSCs to differentiate towards airway epithelial cells.

  2. Wnt signaling in ovarian development inhibits Sf1 activation of Sox9 via the Tesco enhancer.

    Science.gov (United States)

    Bernard, Pascal; Ryan, Janelle; Sim, Helena; Czech, Daniel P; Sinclair, Andrew H; Koopman, Peter; Harley, Vincent R

    2012-02-01

    Genome analysis of patients with disorders of sex development, and gain- and loss-of-function studies in mice indicate that gonadal development is regulated by opposing signals. In females, the Wnt/β-catenin canonical pathway blocks testicular differentiation by repressing the expression of the Sertoli cell-specific gene Sox9 by an unknown mechanism. Using cell and embryonic gonad culture models, we show that activation of the Wnt/β-catenin pathway inhibits the expression of Sox9 and Amh, whereas mRNA and protein levels of Sry and steroidogenic factor 1 (Sf1), two key transcriptional regulators of Sox9, are not altered. Ectopic activation of Wnt/β-catenin signaling in male gonads led to a loss of Sf1 binding to the Tesco enhancer and absent Sox9 expression that we also observed in wild-type ovaries. Moreover, ectopic Wnt/β-catenin signaling induced the expression of the female somatic cell markers, Bmp2 and Rspo1, as a likely consequence of Sox9 loss. Wnt/β-catenin signaling in XY gonads did not, however, affect gene expression of the steroidogenic Leydig cell Sf1 target gene, Cyp11a1, or Sf1 binding to the Cyp11a1 promoter. Our data support a model in ovary development whereby activation of β-catenin prevents Sf1 binding to the Sox9 enhancer, thereby inhibiting Sox9 expression and Sertoli cell differentiation.

  3. Wnt Signaling in Skeletal Muscle Development and Regeneration.

    Science.gov (United States)

    Girardi, Francesco; Le Grand, Fabien

    2018-01-01

    Wnt is a family of signaling molecules involved in embryogenesis, adult tissue repair, and cancer. They activate canonical and noncanonical Wnt signaling cascades in target cells. Several studies, within the last decades, showed that several Wnt ligands are involved in myogenesis and both canonical and noncanonical Wnt pathways regulate muscle formation and the maintenance of adult tissue homeostasis. In this review, we provide a comprehensive overview of the roles of Wnt signaling during muscle development and an updated description of Wnt functions during muscle repair. Lastly, we discuss the crosstalk between Wnt and TGFβ signaling pathways in skeletal muscle. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Autocrine stimulation of osteoblast activity by Wnt5a in response to TNF-α in human mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Briolay, A. [ICBMS, UMR CNRS 5246, University of Lyon 1, Bâtiment Raulin, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Lencel, P. [Physiopathology of Inflammatory Bone Diseases, EA4490, ULCO. Quai Masset, Bassin Napoléon BP120, 62327 Boulogne/Mer (France); Bessueille, L. [ICBMS, UMR CNRS 5246, University of Lyon 1, Bâtiment Raulin, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Caverzasio, J. [Service of Bone Diseases, Department of Internal Medicine Specialties, University Hospital of Geneva, CH-1211 Geneva 14 (Switzerland); Buchet, R. [ICBMS, UMR CNRS 5246, University of Lyon 1, Bâtiment Raulin, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Magne, D., E-mail: david.magne@univ-lyon1.fr [ICBMS, UMR CNRS 5246, University of Lyon 1, Bâtiment Raulin, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France)

    2013-01-18

    Highlights: ► Ankylosing spondylitis (AS) leads to bone fusions and ankylosis. ► TNF-α stimulates osteoblasts through growth factors in AS. ► We compare the involvement of canonical vs non-canonical Wnt signaling. ► Canonical Wnt signaling is not involved in TNF-α effects in differentiating hMSCs. ► TNF-α stimulates osteoblasts through Wnt5a autocrine secretion in hMSCs. -- Abstract: Although anti-tumor necrosis factor (TNF)-α treatments efficiently block inflammation in ankylosing spondylitis (AS), they are inefficient to prevent excessive bone formation. In AS, ossification seems more prone to develop in sites where inflammation has resolved following anti-TNF therapy, suggesting that TNF-α indirectly stimulates ossification. In this context, our objectives were to determine and compare the involvement of Wnt proteins, which are potent growth factors of bone formation, in the effects of TNF-α on osteoblast function. In human mesenchymal stem cells (MSCs), TNF-α significantly increased the levels of Wnt10b and Wnt5a. Associated with this effect, TNF-α stimulated tissue-non specific alkaline phosphatase (TNAP) and mineralization. This effect was mimicked by activation of the canonical β-catenin pathway with either anti-Dkk1 antibodies, lithium chloride (LiCl) or SB216763. TNF-α reduced, and activation of β-catenin had little effect on expression of osteocalcin, a late marker of osteoblast differentiation. Surprisingly, TNF-α failed to stabilize β-catenin and Dkk1 did not inhibit TNF-α effects. In fact, Dkk1 expression was also enhanced in response to TNF-α, perhaps explaining why canonical signaling by Wnt10b was not activated by TNF-α. However, we found that Wnt5a also stimulated TNAP in MSCs cultured in osteogenic conditions, and increased the levels of inflammatory markers such as COX-2. Interestingly, treatment with anti-Wnt5a antibodies reduced endogenous TNAP expression and activity. Collectively, these data suggest that increased

  5. Hypoxia targeting copper complexes

    International Nuclear Information System (INIS)

    Dearling, J.L.

    1998-11-01

    The importance and incidence of tumour hypoxia, its measurement and current treatments available, including pharmacological and radiopharmacological methods of targeting hypoxia, are discussed. A variety of in vitro and in vivo methods for imposing hypoxia have been developed and are reviewed. Copper, its chemistry, biochemistry and radiochemistry, the potential for use of copper radionuclides and its use to date in this field is considered with particular reference to the thiosemicarbazones. Their biological activity, metal chelation, in vitro and in vivo studies of their radiocopper complexes and the potential for their use as hypoxia targeting radiopharmaceuticals is described. The reduction of the copper(II) complex to copper(l), its pivotal importance in their biological behaviour, and the potential for manipulation of this to effect hypoxia selectivity are described. An in vitro method for assessing the hypoxia selectivity of radiopharmaceuticals is reported. The rapid deoxygenation and high viability of a mammalian cell culture in this system is discussed and factors which may affect the cellular uptake of a radiopharmaceutical are described. The design, synthesis and complexation with copper and radiocopper of a range of bis(thiosemicarbazones) is reported. Synthesis of these compounds is simple giving high yields of pure products. The characteristics of the radiocopper complexes ( 64 Cu) including lipophilicity and redox activity are reported (reduction potentials in the range -0.314 - -0.590 V). High cellular uptakes of the radiocopper complexes of the ligands, in hypoxic and normoxic EMT6 and CHO320 cells, were observed. Extremes of selectivity are shown ranging from the hypoxia selective 64 Cu(II)ATSM to normoxic cell selective 64 Cu(II)GTS. The selectivities observed are compared with the physico chemical characteristics of the complexes. A good correlation exists between selectivity of the complex and its Cu(II)/Cu(I) reduction potential, with hypoxia

  6. Mechanisms of Wnt signaling and control.

    Science.gov (United States)

    Grainger, Stephanie; Willert, Karl

    2018-03-30

    The Wnt signaling pathway is a highly conserved system that regulates complex biological processes across all metazoan species. At the cellular level, secreted Wnt proteins serve to break symmetry and provide cells with positional information that is critical to the patterning of the entire body plan. At the organismal level, Wnt signals are employed to orchestrate fundamental developmental processes, including the specification of the anterior-posterior body axis, induction of the primitive streak and ensuing gastrulation movements, and the generation of cell and tissue diversity. Wnt functions extend into adulthood where they regulate stem cell behavior, tissue homeostasis, and damage repair. Disruption of Wnt signaling activity during embryonic development or in adults results in a spectrum of abnormalities and diseases, including cancer. The molecular mechanisms that underlie the myriad of Wnt-regulated biological effects have been the subject of intense research for over three decades. This review is intended to summarize our current understanding of how Wnt signals are generated and interpreted. This article is categorized under: Biological Mechanisms > Cell Signaling Developmental Biology > Stem Cell Biology and Regeneration. © 2018 Wiley Periodicals, Inc.

  7. The function of endocytosis in Wnt signaling.

    Science.gov (United States)

    Brunt, Lucy; Scholpp, Steffen

    2018-03-01

    Wnt growth factors regulate one of the most important signaling networks during development, tissue homeostasis and disease. Despite the biological importance of Wnt signaling, the mechanism of endocytosis during this process is ill described. Wnt molecules can act as paracrine signals, which are secreted from the producing cells and transported through neighboring tissue to activate signaling in target cells. Endocytosis of the ligand is important at several stages of action: One central function of endocytic trafficking in the Wnt pathway occurs in the source cell. Furthermore, the β-catenin-dependent Wnt ligands require endocytosis for signal activation and to regulate gene transcription in the responding cells. Alternatively, Wnt/β-catenin-independent signaling regulates endocytosis of cell adherence plaques to control cell migration. In this comparative review, we elucidate these three fundamental interconnected functions, which together regulate cellular fate and cellular behavior. Based on established hypotheses and recent findings, we develop a revised picture for the complex function of endocytosis in the Wnt signaling network.

  8. Wnt signaling inhibits CTL memory programming.

    Science.gov (United States)

    Xiao, Zhengguo; Sun, Zhifeng; Smyth, Kendra; Li, Lei

    2013-12-01

    Induction of functional CTLs is one of the major goals for vaccine development and cancer therapy. Inflammatory cytokines are critical for memory CTL generation. Wnt signaling is important for CTL priming and memory formation, but its role in cytokine-driven memory CTL programming is unclear. We found that wnt signaling inhibited IL-12-driven CTL activation and memory programming. This impaired memory CTL programming was attributed to up-regulation of eomes and down-regulation of T-bet. Wnt signaling suppressed the mTOR pathway during CTL activation, which was different to its effects on other cell types. Interestingly, the impaired memory CTL programming by wnt was partially rescued by mTOR inhibitor rapamycin. In conclusion, we found that crosstalk between wnt and the IL-12 signaling inhibits T-bet and mTOR pathways and impairs memory programming which can be recovered in part by rapamycin. In addition, direct inhibition of wnt signaling during CTL activation does not affect CTL memory programming. Therefore, wnt signaling may serve as a new tool for CTL manipulation in autoimmune diseases and immune therapy for certain cancers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Nerve Blocks

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Nerve Blocks A nerve block is an injection to ... the limitations of Nerve Block? What is a Nerve Block? A nerve block is an anesthetic and/ ...

  10. Wnt Signalling in Gastrointestinal Epithelial Stem Cells

    Directory of Open Access Journals (Sweden)

    Dustin J. Flanagan

    2018-03-01

    Full Text Available Wnt signalling regulates several cellular functions including proliferation, differentiation, apoptosis and migration, and is critical for embryonic development. Stem cells are defined by their ability for self-renewal and the ability to be able to give rise to differentiated progeny. Consequently, they are essential for the homeostasis of many organs including the gastrointestinal tract. This review will describe the huge advances in our understanding of how stem cell functions in the gastrointestinal tract are regulated by Wnt signalling, including how deregulated Wnt signalling can hijack these functions to transform cells and lead to cancer.

  11. Three-dimensional organoid culture reveals involvement of Wnt/β-catenin pathway in proliferation of bladder cancer cells.

    Science.gov (United States)

    Yoshida, Takahiro; Sopko, Nikolai A; Kates, Max; Liu, Xiaopu; Joice, Gregory; McConkey, David J; Bivalacqua, Trinity J

    2018-02-16

    There has been increasing awareness of the importance of three-dimensional culture of cancer cells. Tumor cells growing as multicellular spheroids in three-dimensional culture, alternatively called organoids, are widely believed to more closely mimic solid tumors in situ . Previous studies concluded that the Wnt/β-catenin pathway is required for regeneration of the normal urothelium after injury and that β-catenin is upregulated in human bladder cancers, but no clear evidence has been advanced to support the idea that the Wnt/β-catenin pathway is directly involved in deregulated proliferation and the other malignant characteristics of bladder cancer cells. Here we report that the Wnt/β-catenin pathway activator, CHIR99021, promoted proliferation of established human bladder cancer cell lines when they were grown in organoid culture but not when they were grown in conventional adherent cultures. CHIR99021 activated Wnt/β-catenin pathway in bladder cancer cell lines in organoid culture. CHIR99021 also stimulated proliferation and the Wnt/b-catenin pathway in primary human bladder cancer organoids. RNAi-mediated knockdown of β-catenin blocked growth of organoids. The effects of CHIR99021 were associated with decreased expression of the urothelial terminal differentiation marker, cytokeratin 20. Our data suggest that the Wnt/β-catenin pathway is required for the proliferation of bladder cancer cells in three-dimensional organoid culture and provide a concrete example of why organoid culture is important for cancer research.

  12. Crosstalk between Wnt/β-catenin and estrogen receptor signaling synergistically promotes osteogenic differentiation of mesenchymal progenitor cells.

    Directory of Open Access Journals (Sweden)

    Yanhong Gao

    Full Text Available Osteogenic differentiation from mesenchymal progenitor cells (MPCs are initiated and regulated by a cascade of signaling events. Either Wnt/β-catenin or estrogen signaling pathway has been shown to play an important role in regulating skeletal development and maintaining adult tissue homeostasis. Here, we investigate the potential crosstalk and synergy of these two signaling pathways in regulating osteogenic differentiation of MPCs. We find that the activation of estrogen receptor (ER signaling by estradiol (E2 or exogenously expressed ERα in MPCs synergistically enhances Wnt3A-induced early and late osteogenic markers, as well as matrix mineralization. The E2 or ERα-mediated synergy can be effectively blocked by ERα antagonist tamoxifen. E2 stimulation can enhance endochondral ossification of Wnt3A-transduced mouse fetal limb explants. Furthermore, exogenously expressed ERα significantly enhances the maturity and mineralization of Wnt3A-induced subcutaneous and intramuscular ectopic bone formation. Mechanistically, we demonstrate that E2 does not exert any detectable effect on β-catenin/Tcf reporter activity. However, ERα expression is up-regulated within the first 48h in AdWnt3A-transduced MPCs, whereas ERβ expression is significantly inhibited within 24h. Moreover, the key enzyme for the biosynthesis of estrogens aromatase is modulated by Wnt3A in a biphasic manner, up-regulated at 24h but reduced after 48h. Our results demonstrate that, while ER signaling acts synergistically with Wnt3A in promoting osteogenic differentiation, Wnt3A may crosstalk with ER signaling by up-regulating ERα expression and down-regulating ERβ expression in MPCs. Thus, the signaling crosstalk and synergy between these two pathways should be further explored as a potential therapeutic approach to combating bone and skeletal disorders, such as fracture healing and osteoporosis.

  13. Epilepsy and the Wnt Signaling Pathway

    Science.gov (United States)

    2015-06-01

    forebrain development. The primary target is Wnt 8b, which is elevated in this period 4. Fox G1 is also genetically associated with infantile spasms 8...the Warburg effect’s role in non- cancerous tissues is largely unexplored. Second, in other diseases such as diabetes , Wnt signaling has emerged as...epilepsy and infantile spasms, we found that both mechanisms appeared to contribute. Two of the three genes came from our observation that several genes

  14. The way Wnt works: Components and mechanism

    Science.gov (United States)

    SAITO-DIAZ, KENYI; CHEN, TONY W.; WANG, XIAOXI; THORNE, CURTIS A.; WALLACE, HEATHER A.; PAGE-MCCAW, ANDREA; LEE, ETHAN

    2013-01-01

    The canonical Wnt/β-catenin pathway is an ancient and evolutionarily conserved signaling pathway that is required for the proper development of all metazoans, from the basal demosponge Amphimedon queenslandica to humans. Misregulation of Wnt signaling is implicated in many human diseases, making this pathway an intense area of research in industry as well as academia. In this review, we explore our current understanding of the molecular steps involved in the transduction of a Wnt signal. We will focus on how the critical Wnt pathway component, β-catenin, is in a “futile cycle” of constant synthesis and degradation and how this cycle is disrupted upon pathway activation. We describe the role of the Wnt pathway in major human cancers and in the control of stem cell self-renewal in the developing organism and in adults. Finally, we describe well-accepted criteria that have been proposed as evidence for the involvement of a molecule in regulating the canonical Wnt pathway. PMID:23256519

  15. Wnt and Hedgehog Signaling Regulate the Differentiation of F9 Cells into Extraembryonic Endoderm

    Directory of Open Access Journals (Sweden)

    Gurjoth S. J. Deol

    2017-10-01

    Full Text Available Mouse F9 cells differentiate into primitive extraembryonic endoderm (PrE when treated with retinoic acid (RA, and this is accompanied by an up-regulation of Gata6. The role of the GATA6 network in PrE differentiation is known, and we have shown it directly activates Wnt6. Canonical Wnt/β-catenin signaling is required by F9 cells to differentiate to PrE, and this, like most developmental processes, requires input from one or more additional pathways. We found both RA and Gata6 overexpression, can induce the expression of Indian Hedgehog (Ihh and a subset of its target genes through Gli activation during PrE induction. Chemical activation of the Hh pathway using a Smoothened agonist (SAG also increased Gli reporter activity, and as expected, when Hh signaling was blocked with a Smoothened antagonist, cyclopamine, this RA-induced reporter activity was reduced. Interestingly, SAG alone failed to induce markers of PrE differentiation, and had no effect on Wnt/β-catenin-dependent TCF-LEF reporter activity. The expected increase in Wnt/β-catenin-dependent TCF-LEF reporter activity and PrE markers induced by RA was, however, blocked by cyclopamine. Finally, inhibiting GSK3 activity with BIO increased both TCF-LEF and Gli reporter activities. Together, we demonstrate the involvement of Hh signaling in the RA-induced differentiation of F9 cells into PrE, and while the activation of the Hh pathway itself is not sufficient, it as well as active Wnt/β-catenin are necessary for F9 cell differentiation.

  16. Surrogate Wnt agonists that phenocopy canonical Wnt and β-catenin signalling

    NARCIS (Netherlands)

    Janda, Claudia Y.; Dang, Luke T.; You, Changjiang; Chang, Junlei; Lau, Wim De; Zhong, Zhendong A.; Yan, Kelley S.; Marecic, Owen; Siepe, DIrk; Li, Xingnan; Moody, James D.; Williams, Bart O.; Clevers, Hans; Piehler, Jacob; Baker, David; Kuo, Calvin J.; Garcia, K. Christopher

    2017-01-01

    Wnt proteins modulate cell proliferation and differentiation and the self-renewal of stem cells by inducing β-catenin-dependent signalling through the Wnt receptor frizzled (FZD) and the co-receptors LRP5 and LRP6 to regulate cell fate decisions and the growth and repair of several tissues. The 19

  17. Dissecting the Wnt secretion pathway: key questions on the modification and intracellular trafficking of Wnt proteins

    NARCIS (Netherlands)

    Harterink, M.; Korswagen, H.C.

    2012-01-01

    The Wnt family of signalling proteins has essential functions in development and adult tissue homoeostasis throughout the animal kingdom. Although signalling cascades triggered by Wnt proteins have been extensively studied, much remains to be learned about how Wnts are produced and secreted. Over

  18. Sailing with the Wnt: charting the Wnt processing and secretion route

    NARCIS (Netherlands)

    Lorenowicz, M.J.; Korswagen, H.C.

    2009-01-01

    Wnt proteins are members of a highly conserved family of signalling molecules that play a central role in development and disease. During the past years, the different signalling pathways that are triggered by Wnt proteins have been studied in detail, but it is still largely unknown how a functional

  19. Wnt some lose some: transcriptional governance of stem cells by Wnt/β-catenin signaling

    Science.gov (United States)

    Lien, Wen-Hui; Fuchs, Elaine

    2014-01-01

    In mammals, Wnt/β-catenin signaling features prominently in stem cells and cancers, but how and for what purposes have been matters of much debate. In this review, we summarize our current knowledge of Wnt/β-catenin signaling and its downstream transcriptional regulators in normal and malignant stem cells. We centered this review largely on three types of stem cells—embryonic stem cells, hair follicle stem cells, and intestinal epithelial stem cells—in which the roles of Wnt/β-catenin have been extensively studied. Using these models, we unravel how many controversial issues surrounding Wnt signaling have been resolved by dissecting the diversity of its downstream circuitry and effectors, often leading to opposite outcomes of Wnt/β-catenin-mediated regulation and differences rooted in stage- and context-dependent effects. PMID:25030692

  20. Nitric Oxide Mediates Crosstalk between Interleukin 1β and WNT Signaling in Primary Human Chondrocytes by Reducing DKK1 and FRZB Expression.

    Science.gov (United States)

    Zhong, Leilei; Schivo, Stefano; Huang, Xiaobin; Leijten, Jeroen; Karperien, Marcel; Post, Janine N

    2017-11-22

    Interleukin 1 beta (IL1β) and Wingless-Type MMTV Integration Site Family (WNT) signaling are major players in Osteoarthritis (OA) pathogenesis. Despite having a large functional overlap in OA onset and development, the mechanism of IL1β and WNT crosstalk has remained largely unknown. In this study, we have used a combination of computational modeling and molecular biology to reveal direct or indirect crosstalk between these pathways. Specifically, we revealed a mechanism by which IL1β upregulates WNT signaling via downregulating WNT antagonists, DKK1 and FRZB. In human chondrocytes, IL1β decreased the expression of Dickkopf-1 (DKK1) and Frizzled related protein (FRZB) through upregulation of nitric oxide synthase (iNOS), thereby activating the transcription of WNT target genes. This effect could be reversed by iNOS inhibitor 1400W, which restored DKK1 and FRZB expression and their inhibitory effect on WNT signaling. In addition, 1400W also inhibited both the matrix metalloproteinase (MMP) expression and cytokine-induced apoptosis. We concluded that iNOS/NO play a pivotal role in the inflammatory response of human OA through indirect upregulation of WNT signaling. Blocking NO production may inhibit the loss of the articular phenotype in OA by preventing downregulation of the expression of DKK1 and FRZB.

  1. wnt3a but not wnt11 supports self-renewal of embryonic stem cells

    International Nuclear Information System (INIS)

    Singla, Dinender K.; Schneider, David J.; LeWinter, Martin M.; Sobel, Burton E.

    2006-01-01

    wnt proteins (wnts) promote both differentiation of midbrain dopaminergic cells and self-renewal of haematopoietic stem cells. Mouse embryonic stem (ES) cells can be maintained and self-renew on mouse feeder cell layers or in media containing leukemia inhibitory factor (LIF). However, the effects of wnts on ES cells self-renewal and differentiation are not clearly understood. In the present study, we found that conditioned medium prepared from L cells expressing wnt3a can replace feeder cell layers and medium containing LIF in maintaining ES cells in the proliferation without differentiation (self-renewal) state. By contrast, conditioned medium from NIH3T3 cells expressing wnt11 did not. Alkaline phosphatase staining and compact colony formation were used as criteria of cells being in the undifferentiated state. ES cells maintained in medium conditioned by Wnt3a expressing cells underwent freezing and thawing while maintaining properties seen with LIF maintained ES cells. Purified wnt3a did not maintain self-renewal of ES cells for prolonged intervals. Thus, other factors in the medium conditioned by wnt3a expressing cells may have contributed to maintenance of ES cells in a self-renewal state. Pluripotency of ES cells was determined with the use of embryoid bodies in vitro. PD98059, a MEK specific inhibitor, promoted the growth of undifferentiated ES cells maintained in conditioned medium from wnt3a expressing cells. By contrast, the P38 MAPK inhibitor SB230580 did not, suggesting a role for the MEK pathway in self-renewal and differentiation of ES cells maintained in the wnt3a cell conditioned medium. Thus, our results show that conditioned medium from wnt3a but not wnt11 expressing cells can maintain ES cells in self-renewal and in a pluripotent state

  2. Canonical Wnt signaling in differentiated osteoblasts controls osteoclast differentiation.

    NARCIS (Netherlands)

    Glass, D.A.; Bialek, P.; Ahn, J.D.; Starbuck, M.; Patel, M.S.; Clevers, J.C.; Taketo, M.M.; Long, F.; McMahon, A.P.; Lang, R.A.; Karsenty, G.

    2005-01-01

    Inactivation of beta-catenin in mesenchymal progenitors prevents osteoblast differentiation; inactivation of Lrp5, a gene encoding a likely Wnt coreceptor, results in low bone mass (osteopenia) by decreasing bone formation. These observations indicate that Wnt signaling controls osteoblast

  3. PKA activity exacerbates hypoxia-induced ROS formation and hypoxic injury in PC-12 cells.

    Science.gov (United States)

    Gozal, Evelyne; Metz, Cynthia J; Dematteis, Maurice; Sachleben, Leroy R; Schurr, Avital; Rane, Madhavi J

    2017-09-05

    Hypoxia is a primary factor in many pathological conditions. Hypoxic cell death is commonly attributed to metabolic failure and oxidative injury. cAMP-dependent protein kinase A (PKA) is activated in hypoxia and regulates multiple enzymes of the mitochondrial electron transport chain, thus may be implicated in cellular energy depletion and hypoxia-induced cell death. Wild type (WT) PC-12 cells and PKA activity-deficient 123.7 PC-12 cells were exposed to 3, 6, 12 and 24h hypoxia (0.1% or 5% O 2 ). Hypoxia, at 24h 0.1% O 2 , induced cell death and increased reactive oxygen species (ROS) in WT PC-12 cells. Despite lower ATP levels in normoxic 123.7 cells than in WT cells, hypoxia only decreased ATP levels in WT cells. However, menadione-induced oxidative stress similarly affected both cell types. While mitochondrial COX IV expression remained consistently higher in 123.7 cells, hypoxia decreased COX IV expression in both cell types. N-acetyl cysteine antioxidant treatment blocked hypoxia-induced WT cell death without preventing ATP depletion. Transient PKA catα expression in 123.7 cells partially restored hypoxia-induced ROS but did not alter ATP levels or COX IV expression. We conclude that PKA signaling contributes to hypoxic injury, by regulating oxidative stress rather than by depleting ATP levels. Therapeutic strategies targeting PKA signaling may improve cellular adaptation and recovery in hypoxic pathologies. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Hypoxia activates muscle-restricted coiled-coil protein (MURC) expression via transforming growth factor-β in cardiac myocytes.

    Science.gov (United States)

    Shyu, Kou-Gi; Cheng, Wen-Pin; Wang, Bao-Wei; Chang, Hang

    2014-03-01

    The expression of MURC (muscle-restricted coiled-coil protein), a hypertrophy-regulated gene, increases during pressure overload. Hypoxia can cause myocardial hypertrophy; however, how hypoxia affects the regulation of MURC in cardiomyocytes undergoing hypertrophy is still unknown. The aim of the present study was to test the hypothesis that hypoxia induces MURC expression in cardiomyocytes during hypertrophy. The expression of MURC was evaluated in cultured rat neonatal cardiomyocytes subjected to hypoxia and in an in vivo model of AMI (acute myocardial infarction) to induce myocardial hypoxia in adult rats. MURC protein and mRNA expression were significantly enhanced by hypoxia. MURC proteins induced by hypoxia were significantly blocked after the addition of PD98059 or ERK (extracellular-signal-regulated kinase) siRNA 30 min before hypoxia. Gel-shift assay showed increased DNA-binding activity of SRF (serum response factor) after hypoxia. PD98059, ERK siRNA and an anti-TGF-β (transforming growth factor-β) antibody abolished the SRF-binding activity enhanced by hypoxia or exogenous administration of TGF-β. A luciferase promoter assay demonstrated increased transcriptional activity of SRF in cardiomyocytes by hypoxia. Increased βMHC (β-myosin heavy chain) and BNP (B-type natriuretic peptide) protein expression and increased protein synthesis was identified after hypoxia with the presence of MURC in hypertrophic cardiomyocytes. MURC siRNA inhibited the hypertrophic marker protein expression and protein synthesis induced by hypoxia. AMI in adult rats also demonstrated increased MURC protein expression in the left ventricular myocardium. In conclusion, hypoxia in cultured rat neonatal cardiomyocytes increased MURC expression via the induction of TGF-β, SRF and the ERK pathway. These findings suggest that MURC plays a role in hypoxia-induced hypertrophy in cardiomyocytes.

  5. DKK1 mediated inhibition of Wnt signaling in postnatal mice leads to loss of TEC progenitors and thymic degeneration.

    Directory of Open Access Journals (Sweden)

    Masako Osada

    2010-02-01

    Full Text Available Thymic epithelial cell (TEC microenvironments are essential for the recruitment of T cell precursors from the bone marrow, as well as the subsequent expansion and selection of thymocytes resulting in a mature self-tolerant T cell repertoire. The molecular mechanisms, which control both the initial development and subsequent maintenance of these critical microenvironments, are poorly defined. Wnt signaling has been shown to be important to the development of several epithelial tissues and organs. Regulation of Wnt signaling has also been shown to impact both early thymocyte and thymic epithelial development. However, early blocks in thymic organogenesis or death of the mice have prevented analysis of a role of canonical Wnt signaling in the maintenance of TECs in the postnatal thymus.Here we demonstrate that tetracycline-regulated expression of the canonical Wnt inhibitor DKK1 in TECs localized in both the cortex and medulla of adult mice, results in rapid thymic degeneration characterized by a loss of DeltaNP63(+ Foxn1(+ and Aire(+ TECs, loss of K5K8DP TECs thought to represent or contain an immature TEC progenitor, decreased TEC proliferation and the development of cystic structures, similar to an aged thymus. Removal of DKK1 from DKK1-involuted mice results in full recovery, suggesting that canonical Wnt signaling is required for the differentiation or proliferation of TEC populations needed for maintenance of properly organized adult thymic epithelial microenvironments.Taken together, the results of this study demonstrate that canonical Wnt signaling within TECs is required for the maintenance of epithelial microenvironments in the postnatal thymus, possibly through effects on TEC progenitor/stem cell populations. Downstream targets of Wnt signaling, which are responsible for maintenance of these TEC progenitors may provide useful targets for therapies aimed at counteracting age associated thymic involution or the premature thymic

  6. Regulation of Wnt/β-catenin signaling by posttranslational modifications

    Science.gov (United States)

    2014-01-01

    The canonical Wnt signaling pathway (or Wnt/β-catenin pathway) plays a pivotal role in embryonic development and adult homeostasis; deregulation of the Wnt pathway contributes to the initiation and progression of human diseases including cancer. Despite its importance in human biology and disease, how regulation of the Wnt/β-catenin pathway is achieved remains largely undefined. Increasing evidence suggests that post-translational modifications (PTMs) of Wnt pathway components are essential for the activation of the Wnt/β-catenin pathway. PTMs create a highly dynamic relay system that responds to Wnt stimulation without requiring de novo protein synthesis and offer a platform for non-Wnt pathway components to be involved in the regulation of Wnt signaling, hence providing alternative opportunities for targeting the Wnt pathway. This review highlights the current status of PTM-mediated regulation of the Wnt/β-catenin pathway with a focus on factors involved in Wnt-mediated stabilization of β-catenin. PMID:24594309

  7. WNT-er is coming’: WNT signalling in chronic lung diseases

    Science.gov (United States)

    Baarsma, H A

    2017-01-01

    Chronic lung diseases represent a major public health problem with only limited therapeutic options. An important unmet need is to identify compounds and drugs that target key molecular pathways involved in the pathogenesis of chronic lung diseases. Over the last decade, there has been extensive interest in investigating Wingless/integrase-1 (WNT) signalling pathways; and WNT signal alterations have been linked to pulmonary disease pathogenesis and progression. Here, we comprehensively review the cumulative evidence for WNT pathway alterations in chronic lung pathologies, including idiopathic pulmonary fibrosis, pulmonary arterial hypertension, asthma and COPD. While many studies have focused on the canonical WNT/β-catenin signalling pathway, recent reports highlight that non-canonical WNT signalling may also significantly contribute to chronic lung pathologies; these studies will be particularly featured in this review. We further discuss recent advances uncovering the role of WNT signalling early in life, the potential of pharmaceutically modulating WNT signalling pathways and highlight (pre)clinical studies describing promising new therapies for chronic lung diseases. PMID:28416592

  8. WNT signaling controls expression of pro-apoptotic BOK and BAX in intestinal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Zeilstra, Jurrit; Joosten, Sander P.J. [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands); Wensveen, Felix M. [Department of Experimental Immunology, Academic Medical Center, Amsterdam (Netherlands); Dessing, Mark C.; Schuetze, Denise M. [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands); Eldering, Eric [Department of Experimental Immunology, Academic Medical Center, Amsterdam (Netherlands); Spaargaren, Marcel [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands); Pals, Steven T., E-mail: s.t.pals@amc.uva.nl [Department of Pathology, Academic Medical Center, University of Amsterdam (Netherlands)

    2011-03-04

    Research highlights: {yields} Intestinal adenomas initiated by aberrant activation of the WNT pathway displayed an increased sensitivity to apoptosis. {yields} Expression profiling of apoptosis-related genes in Apc{sup Min/+} mice revealed the differential expression of pro-apoptotic Bok and Bax. {yields} APC-mutant adenomatous crypts in FAP patients showed strongly increased BAX immunoreactivity. {yields} Blocking of {beta}-catenin/TCF-4-mediated signaling in colon cancer cells reduced the expression of BOK and BAX. -- Abstract: In a majority of cases, colorectal cancer is initiated by aberrant activation of the WNT signaling pathway. Mutation of the genes encoding the WNT signaling components adenomatous polyposis coli or {beta}-catenin causes constitutively active {beta}-catenin/TCF-mediated transcription, driving the transformation of intestinal crypts to cancer precursor lesions, called dysplastic aberrant crypt foci. Deregulated apoptosis is a hallmark of adenomatous colon tissue. However, the contribution of WNT signaling to this process is not fully understood. We addressed this role by analyzing the rate of epithelial apoptosis in aberrant crypts and adenomas of the Apc{sup Min/+} mouse model. In comparison with normal crypts and adenomas, aberrant crypts displayed a dramatically increased rate of apoptotic cell death. Expression profiling of apoptosis-related genes along the crypt-villus axis and in Apc mutant adenomas revealed increased expression of two pro-apoptotic Bcl-2 family members in intestinal adenomas, Bok and Bax. Analysis of the colon of familial adenomatous polyposis (FAP) patients along the crypt-to-surface axis, and of dysplastic crypts, corroborated this expression pattern. Disruption of {beta}-catenin/TCF-4-mediated signaling in the colorectal cancer cell line Ls174T significantly decreased BOK and BAX expression, confirming WNT-dependent regulation in intestinal epithelial cells. Our results suggest a feedback mechanism by which

  9. WNT signaling controls expression of pro-apoptotic BOK and BAX in intestinal cancer

    International Nuclear Information System (INIS)

    Zeilstra, Jurrit; Joosten, Sander P.J.; Wensveen, Felix M.; Dessing, Mark C.; Schuetze, Denise M.; Eldering, Eric; Spaargaren, Marcel; Pals, Steven T.

    2011-01-01

    Research highlights: → Intestinal adenomas initiated by aberrant activation of the WNT pathway displayed an increased sensitivity to apoptosis. → Expression profiling of apoptosis-related genes in Apc Min/+ mice revealed the differential expression of pro-apoptotic Bok and Bax. → APC-mutant adenomatous crypts in FAP patients showed strongly increased BAX immunoreactivity. → Blocking of β-catenin/TCF-4-mediated signaling in colon cancer cells reduced the expression of BOK and BAX. -- Abstract: In a majority of cases, colorectal cancer is initiated by aberrant activation of the WNT signaling pathway. Mutation of the genes encoding the WNT signaling components adenomatous polyposis coli or β-catenin causes constitutively active β-catenin/TCF-mediated transcription, driving the transformation of intestinal crypts to cancer precursor lesions, called dysplastic aberrant crypt foci. Deregulated apoptosis is a hallmark of adenomatous colon tissue. However, the contribution of WNT signaling to this process is not fully understood. We addressed this role by analyzing the rate of epithelial apoptosis in aberrant crypts and adenomas of the Apc Min/+ mouse model. In comparison with normal crypts and adenomas, aberrant crypts displayed a dramatically increased rate of apoptotic cell death. Expression profiling of apoptosis-related genes along the crypt-villus axis and in Apc mutant adenomas revealed increased expression of two pro-apoptotic Bcl-2 family members in intestinal adenomas, Bok and Bax. Analysis of the colon of familial adenomatous polyposis (FAP) patients along the crypt-to-surface axis, and of dysplastic crypts, corroborated this expression pattern. Disruption of β-catenin/TCF-4-mediated signaling in the colorectal cancer cell line Ls174T significantly decreased BOK and BAX expression, confirming WNT-dependent regulation in intestinal epithelial cells. Our results suggest a feedback mechanism by which uncontrolled epithelial cell proliferation in the

  10. miR-34b/c Regulates Wnt1 and Enhances Mesencephalic Dopaminergic Neuron Differentiation

    Directory of Open Access Journals (Sweden)

    Roberto De Gregorio

    2018-04-01

    Full Text Available Summary: The differentiation of dopaminergic neurons requires concerted action of morphogens and transcription factors acting in a precise and well-defined time window. Very little is known about the potential role of microRNA in these events. By performing a microRNA-mRNA paired microarray screening, we identified miR-34b/c among the most upregulated microRNAs during dopaminergic differentiation. Interestingly, miR-34b/c modulates Wnt1 expression, promotes cell cycle exit, and induces dopaminergic differentiation. When combined with transcription factors ASCL1 and NURR1, miR-34b/c doubled the yield of transdifferentiated fibroblasts into dopaminergic neurons. Induced dopaminergic (iDA cells synthesize dopamine and show spontaneous electrical activity, reversibly blocked by tetrodotoxin, consistent with the electrophysiological properties featured by brain dopaminergic neurons. Our findings point to a role for miR-34b/c in neuronal commitment and highlight the potential of exploiting its synergy with key transcription factors in enhancing in vitro generation of dopaminergic neurons. : In this article, Bellenchi and colleagues show that the microRNA miR-34b/c is expressed in FACS-purified Pitx3-GFP+ neurons and promotes dopaminergic differentiation by negative modulating Wnt1 and the downstream WNT signaling pathway. Induced dopaminergic cells, expressing miR-34b/c, synthesize dopamine and show the electrophysiological properties featured by brain dopaminergic neurons. Keywords: microRNA, dopamine, mESC, miR34b/c, epiSC, transdifferentiation, Wnt1, Wnt pathway, reprogramming

  11. Impaired Wnt Signaling in the Prefrontal Cortex of Alzheimer's Disease

    DEFF Research Database (Denmark)

    Folke, Jonas; Pakkenberg, Bente; Brudek, Tomasz

    2018-01-01

    Wnt pathway is involved in synaptic plasticity and neuronal survival, and alterations in Wnt signaling have previously been reported both in aging and neurodegenerative diseases, including Alzheimer's disease (AD). This study sought to evaluate Wnt signaling pathway interplay integrity across......, in addition to downstream effects associated with disease progression and cognitive decline. This study is the first that comprehensively evaluates Wnt signaling pathway in the prefrontal cortical lobe structures of AD brains, in relation to age-related coordinated Wnt signaling changes. Our findings further...

  12. Wnt signaling in triple-negative breast cancer

    Science.gov (United States)

    Pohl, SÖ-G; Brook, N; Agostino, M; Arfuso, F; Kumar, A P; Dharmarajan, A

    2017-01-01

    Wnt signaling regulates a variety of cellular processes, including cell fate, differentiation, proliferation and stem cell pluripotency. Aberrant Wnt signaling is a hallmark of many cancers. An aggressive subtype of breast cancer, known as triple-negative breast cancer (TNBC), demonstrates dysregulation in canonical and non-canonical Wnt signaling. In this review, we summarize regulators of canonical and non-canonical Wnt signaling, as well as Wnt signaling dysfunction that mediates the progression of TNBC. We review the complex molecular nature of TNBC and the emerging therapies that are currently under investigation for the treatment of this disease. PMID:28368389

  13. TMEM59 potentiates Wnt signaling by promoting signalosome formation.

    Science.gov (United States)

    Gerlach, Jan P; Jordens, Ingrid; Tauriello, Daniele V F; van 't Land-Kuper, Ineke; Bugter, Jeroen M; Noordstra, Ivar; van der Kooij, Johanneke; Low, Teck Y; Pimentel-Muiños, Felipe X; Xanthakis, Despina; Fenderico, Nicola; Rabouille, Catherine; Heck, Albert J R; Egan, David A; Maurice, Madelon M

    2018-04-09

    Wnt/β-catenin signaling controls development and adult tissue homeostasis by regulating cell proliferation and cell fate decisions. Wnt binding to its receptors Frizzled (FZD) and low-density lipoprotein-related 6 (LRP6) at the cell surface initiates a signaling cascade that leads to the transcription of Wnt target genes. Upon Wnt binding, the receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The molecular basis of signalosome formation and regulation remains elusive, largely due to the lack of tools to analyze its endogenous components. Here, we use internally tagged Wnt3a proteins to isolate and characterize activated, endogenous Wnt receptor complexes by mass spectrometry-based proteomics. We identify the single-span membrane protein TMEM59 as an interactor of FZD and LRP6 and a positive regulator of Wnt signaling. Mechanistically, TMEM59 promotes the formation of multimeric Wnt-FZD assemblies via intramembrane interactions. Subsequently, these Wnt-FZD-TMEM59 clusters merge with LRP6 to form mature Wnt signalosomes. We conclude that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps that involve regulated intramembrane interactions. Copyright © 2018 the Author(s). Published by PNAS.

  14. Winding through the WNT pathway during cellular development and demise.

    Science.gov (United States)

    Li, F; Chong, Z Z; Maiese, K

    2006-01-01

    In slightly over a period of twenty years, our comprehension of the cellular and molecular mechanisms that govern the Wnt signaling pathway continue to unfold. The Wnt proteins were initially implicated in viral carcinogenesis experiments associated with mammary tumors, but since this period investigations focusing on the Wnt pathways and their transmembrane receptors termed Frizzled have been advanced to demonstrate the critical nature of Wnt for the development of a variety of cell populations as well as the potential of the Wnt pathway to avert apoptotic injury. In particular, Wnt signaling plays a significant role in both the cardiovascular and nervous systems during embryonic cell patterning, proliferation, differentiation, and orientation. Furthermore, modulation of Wnt signaling under specific cellular influences can either promote or prevent the early and late stages of apoptotic cellular injury in neurons, endothelial cells, vascular smooth muscle cells, and cardiomyocytes. A number of downstream signal transduction pathways can mediate the biological response of the Wnt proteins that include Dishevelled, beta-catenin, intracellular calcium, protein kinase C, Akt, and glycogen synthase kinase-3beta. Interestingly, these cellular cascades of the Wnt-Frizzled pathways can participate in several neurodegenerative, vascular, and cardiac disorders and may be closely integrated with the function of trophic factors. Identification of the critical elements that modulate the Wnt-Frizzled signaling pathway should continue to unlock the potential of Wnt pathway for the development of new therapeutic options against neurodegenerative and vascular diseases.

  15. The function and evolution of Wnt genes in arthropods.

    Science.gov (United States)

    Murat, Sophie; Hopfen, Corinna; McGregor, Alistair P

    2010-11-01

    Wnt signalling is required for a wide range of developmental processes, from cleavage to patterning and cell migration. There are 13 subfamilies of Wnt ligand genes and this diverse repertoire appeared very early in metazoan evolution. In this review, we first summarise the known Wnt gene repertoire in various arthropods. Insects appear to have lost several Wnt subfamilies, either generally, such as Wnt3, or in lineage specific patterns, for example, the loss of Wnt7 in Anopheles. In Drosophila and Acyrthosiphon, only seven and six Wnt subfamilies are represented, respectively; however, the finding of nine Wnt genes in Tribolium suggests that arthropods had a larger repertoire ancestrally. We then discuss what is currently known about the expression and developmental function of Wnt ligands in Drosophila and other insects in comparison to other arthropods, such as the spiders Achaearanea and Cupiennius. We conclude that studies of Wnt genes have given us much insight into the developmental roles of some of these ligands. However, given the frequent loss of Wnt genes in insects and the derived development of Drosophila, further studies of these important genes are required in a broader range of arthropods to fully understand their developmental function and evolution. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. The expanding universe of hypoxia.

    Science.gov (United States)

    Zhang, Huafeng; Semenza, Gregg L

    2008-07-01

    Reduced oxygen availability (hypoxia) is sensed and transduced into changes in the activity or expression of cellular macromolecules. These responses impact on virtually all areas of biology and medicine. In this meeting report, we summarize major developments in the field that were presented at the 2008 Keystone Symposium on Cellular, Physiological, and Pathogenic Responses to Hypoxia.

  17. A novel gene's role in an ancient mechanism: secreted Frizzled-related protein 1 is a critical component in the anterior-posterior Wnt signaling network that governs the establishment of the anterior neuroectoderm in sea urchin embryos.

    Science.gov (United States)

    Khadka, Anita; Martínez-Bartolomé, Marina; Burr, Stephanie D; Range, Ryan C

    2018-01-01

    The anterior neuroectoderm (ANE) in many deuterostome embryos (echinoderms, hemichordates, urochordates, cephalochordates, and vertebrates) is progressively restricted along the anterior-posterior axis to a domain around the anterior pole. In the sea urchin embryo, three integrated Wnt signaling branches (Wnt/β-catenin, Wnt/JNK, and Wnt/PKC) govern this progressive restriction process, which begins around the 32- to 60-cell stage and terminates by the early gastrula stage. We previously have established that several secreted Wnt modulators of the Dickkopf and secreted Frizzled-related protein families (Dkk1, Dkk3, and sFRP-1/5) are expressed within the ANE and play important roles in modulating the Wnt signaling network during this process. In this study, we use morpholino and dominant-negative interference approaches to characterize the function of a novel Frizzled-related protein, secreted Frizzled-related protein 1 (sFRP-1), during ANE restriction. sFRP-1 appears to be related to a secreted Wnt modulator, sFRP3/4, that is essential to block Wnt signaling and establish the ANE in vertebrates. Here, we show that the sea urchin sFRP3/4 orthologue is not expressed during ANE restriction in the sea urchin embryo. Instead, our results indicate that ubiquitously expressed maternal sFRP-1 and Fzl1/2/7 signaling act together as early as the 32- to 60-cell stage to antagonize the ANE restriction mechanism mediated by Wnt/β-catenin and Wnt/JNK signaling. Then, starting from the blastula stage, Fzl5/8 signaling activates zygotic sFRP-1 within the ANE territory, where it works with the secreted Wnt antagonist Dkk1 (also activated by Fzl5/8 signaling) to antagonize Wnt1/Wnt8-Fzl5/8-JNK signaling in a negative feedback mechanism that defines the outer ANE territory boundary. Together, these data indicate that maternal and zygotic sFRP-1 protects the ANE territory by antagonizing the Wnt1/Wnt8-Fzl5/8-JNK signaling pathway throughout ANE restriction, providing precise

  18. A novel gene’s role in an ancient mechanism: secreted Frizzled-related protein 1 is a critical component in the anterior–posterior Wnt signaling network that governs the establishment of the anterior neuroectoderm in sea urchin embryos

    Directory of Open Access Journals (Sweden)

    Anita Khadka

    2018-01-01

    Full Text Available Abstract The anterior neuroectoderm (ANE in many deuterostome embryos (echinoderms, hemichordates, urochordates, cephalochordates, and vertebrates is progressively restricted along the anterior–posterior axis to a domain around the anterior pole. In the sea urchin embryo, three integrated Wnt signaling branches (Wnt/β-catenin, Wnt/JNK, and Wnt/PKC govern this progressive restriction process, which begins around the 32- to 60-cell stage and terminates by the early gastrula stage. We previously have established that several secreted Wnt modulators of the Dickkopf and secreted Frizzled-related protein families (Dkk1, Dkk3, and sFRP-1/5 are expressed within the ANE and play important roles in modulating the Wnt signaling network during this process. In this study, we use morpholino and dominant-negative interference approaches to characterize the function of a novel Frizzled-related protein, secreted Frizzled-related protein 1 (sFRP-1, during ANE restriction. sFRP-1 appears to be related to a secreted Wnt modulator, sFRP3/4, that is essential to block Wnt signaling and establish the ANE in vertebrates. Here, we show that the sea urchin sFRP3/4 orthologue is not expressed during ANE restriction in the sea urchin embryo. Instead, our results indicate that ubiquitously expressed maternal sFRP-1 and Fzl1/2/7 signaling act together as early as the 32- to 60-cell stage to antagonize the ANE restriction mechanism mediated by Wnt/β-catenin and Wnt/JNK signaling. Then, starting from the blastula stage, Fzl5/8 signaling activates zygotic sFRP-1 within the ANE territory, where it works with the secreted Wnt antagonist Dkk1 (also activated by Fzl5/8 signaling to antagonize Wnt1/Wnt8–Fzl5/8–JNK signaling in a negative feedback mechanism that defines the outer ANE territory boundary. Together, these data indicate that maternal and zygotic sFRP-1 protects the ANE territory by antagonizing the Wnt1/Wnt8–Fzl5/8–JNK signaling pathway throughout ANE

  19. Wnt5a and Wnt11 are essential for second heart field progenitor development

    OpenAIRE

    Cohen, Ethan David; Miller, Mayumi F.; Wang, Zichao; Moon, Randall T.; Morrisey, Edward E.

    2012-01-01

    Wnt/β-catenin has a biphasic effect on cardiogenesis, promoting the induction of cardiac progenitors but later inhibiting their differentiation. Second heart field progenitors and expression of the second heart field transcription factor Islet1 are inhibited by the loss of β-catenin, indicating that Wnt/β-catenin signaling is necessary for second heart field development. However, expressing a constitutively active β-catenin with Islet1-Cre also inhibits endogenous Islet1 expression, reflectin...

  20. Hypoxia activated EGFR signaling induces epithelial to mesenchymal transition (EMT.

    Directory of Open Access Journals (Sweden)

    Ashish Misra

    Full Text Available Metastasis is a multi-step process which requires the conversion of polarized epithelial cells to mesenchymal cells, Epithelial-Mesenchymal Transition (EMT. EMT is essential during embryonic morphogenesis and has been implicated in the progression of primary tumors towards metastasis. Hypoxia is known to induce EMT; however the molecular mechanism is still poorly understood. Using the A431 epithelial cancer cell line, we show that cells grown under hypoxic conditions migrated faster than cells grown under normal oxygen environment. Cells grown under hypoxia showed reduced adhesion to the extracellular matrix (ECM probably due to reduced number of Vinculin patches. Growth under hypoxic conditions also led to down regulation of E-cadherin and up regulation of vimentin expression. The increased motility of cells grown under hypoxia could be due to redistribution of Rac1 to the plasma membrane as opposed to increased expression of Rac1. EGF (Epidermal Growth Factor is a known inducer of EMT and growth of A431 cells in the absence of oxygen led to increased expression of EGFR (EGF Receptor. Treatment of A431 cells with EGF led to reduced cell adhesion to ECM, increased cell motility and other EMT characteristics. Furthermore, this transition was blocked by the monoclonal antibody Cetuximab. Cetuximab also blocked the hypoxia-induced EMT suggesting that cell growth under hypoxic conditions led to activation of EGFR signaling and induction of EMT phenotype.

  1. Wnt ligands signal in a cooperative manner to promote foregut organogenesis

    OpenAIRE

    Miller, Mayumi F.; Cohen, Ethan David; Baggs, Julie E.; Lu, Min Min; Hogenesch, John B.; Morrisey, Edward E.

    2012-01-01

    Endoderm-mesenchyme cross-talk is a central process in the development of foregut-derived organs. How signaling pathways integrate the activity of multiple ligands to guide organ development is poorly understood. We show that two Wnt ligands, Wnt2 and Wnt7b, cooperatively induce Wnt signaling without affecting the stabilization of the Wnt canonical effector β-catenin despite it being necessary for Wnt2–Wnt7b cooperativity. Wnt2–Wnt7b cooperation is specific for mesenchymal cell lineages and t...

  2. Expression patterns of Wnt genes during development of an anterior part of the chicken eye

    OpenAIRE

    Fokina, Valentina M.; Frolova, Elena I.

    2006-01-01

    To address the roles of Wnts in the development of the anterior eye, we used a chicken model to perform comprehensive expression analysis of all Wnt genes during anterior eye development. In analyzing the available genomic sequences, we found that the chicken genome encodes 18 Wnt proteins that are homologous to corresponding human and mouse proteins. The mRNA sequences for 12 chicken Wnt genes are available in GenBank, and mRNAs for six other Wnt genes (Wnt2, Wnt5b, Wnt7b, Wnt8b, Wnt9b and W...

  3. Quercetin enhances hypoxia-mediated apoptosis via direct inhibition of AMPK activity in HCT116 colon cancer.

    Science.gov (United States)

    Kim, Hak-Su; Wannatung, Tirawat; Lee, Sooho; Yang, Woo Kyeom; Chung, Sung Hyun; Lim, Jong-Seok; Choe, Wonchae; Kang, Insug; Kim, Sung-Soo; Ha, Joohun

    2012-09-01

    Tumor hypoxia is considered the best validated target in clinical oncology because of its significant contribution to chemotherapy failure and drug resistance. As an approach to target hypoxia, we assessed the potential of quercetin, a flavonoid widely distributed in plants, as a anticancer agent under hypoxic conditions and examined its pharmacological mechanisms by primarily focusing on the role of AMP-activated protein kinase (AMPK). Quercetin significantly attenuated tumor growth in an HCT116 cancer xenograft in vivo model with a substantial reduction of AMPK activity. In a cell culture system, quercetin more dramatically induced apoptosis of HCT116 cancer cells under hypoxic conditions than normoxic conditions, and this was tightly associated with inhibition of hypoxia-induced AMPK activity. An in vitro kinase assay demonstrated that quercetin directly inhibits AMPK activity. Inhibition of AMPK by expressing a dominant-negative form resulted in an increase of apoptosis under hypoxia, and a constitutively active form of AMPK effectively blocked quercetin-induced apoptosis under hypoxia. Collectively, our data suggest that quercetin directly inhibits hypoxia-induced AMPK, which plays a protective role against hypoxia. Quercetin also reduced the activity of hypoxia-inducible factor-1 (HIF-1), a major transcription factor for adaptive cellular response to hypoxia. Moreover, quercetin sensitized HCT116 cancer cells to the anticancer drugs cisplatin and etoposide under hypoxic conditions. Our findings suggest that AMPK may serve as a novel target for overcoming tumor hypoxia-associated negative aspects.

  4. TRIB3 mediates the expression of Wnt5a and activation of nuclear factor-κB in Porphyromonas endodontalis lipopolysaccharide-treated osteoblasts.

    Science.gov (United States)

    Yu, Y; Qiu, L; Guo, J; Yang, D; Qu, L; Yu, J; Zhan, F; Xue, M; Zhong, M

    2015-08-01

    Porphyromonas endodontalis lipopolysaccharide (LPS) is considered to be correlated with the progression of bone resorption in periodontal and periapical diseases. Wnt5a has recently been implicated in inflammatory processes, but its role is unclear as a P. endodontalis LPS-induced mediator in osteoblasts. Tribbles homolog 3 (TRIB3) encodes a pseudokinase and has been linked to inflammation in certain situations. Here, we found that P. endodontalis LPS induced Wnt5a expression in a dose- and time-dependent manner and it also upregulated translocation, phosphorylation and transcriptional activity of nuclear factor-κB (NF-κB) in MC3T3-E1 cells. Bay 11-7082 blocked the translocation of NF-κB and Wnt5a expression induced by P. endodontalis LPS. Chromatin immunoprecipitation assay further established that induction of Wnt5a by P. endodontalis LPS was mediated through the NF-κB p65 subunit. Additionally, P. endodontalis LPS increased expression of TRIB3 in osteoblasts after 10 h simulated time. Overexpression of TRIB3 enhanced NF-κB phosphorylation and Wnt5a induction, whereas knockdown of TRIB3 inhibited NF-κB phosphorylation and Wnt5a expression in P. endodontalis LPS-stimulated osteoblasts. These results suggest that P. endodontalis LPS has the ability to promote the expression of Wnt5a in mouse osteoblasts, and this induction is mainly mediated by NF-κB pathway. TRIB3 seems to modulate the sustained expression of Wnt5a in osteoblasts stimulated by P. endodontalis LPS, as well as regulating NF-κB phosphorylation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Coastal hypoxia and sediment biogeochemistry

    Directory of Open Access Journals (Sweden)

    J. J. Middelburg

    2009-07-01

    Full Text Available The intensity, duration and frequency of coastal hypoxia (oxygen concentration <63 μM are increasing due to human alteration of coastal ecosystems and changes in oceanographic conditions due to global warming. Here we provide a concise review of the consequences of coastal hypoxia for sediment biogeochemistry. Changes in bottom-water oxygen levels have consequences for early diagenetic pathways (more anaerobic at expense of aerobic pathways, the efficiency of re-oxidation of reduced metabolites and the nature, direction and magnitude of sediment-water exchange fluxes. Hypoxia may also lead to more organic matter accumulation and burial and the organic matter eventually buried is also of higher quality, i.e. less degraded. Bottom-water oxygen levels also affect the organisms involved in organic matter processing with the contribution of metazoans decreasing as oxygen levels drop. Hypoxia has a significant effect on benthic animals with the consequences that ecosystem functions related to macrofauna such as bio-irrigation and bioturbation are significantly affected by hypoxia as well. Since many microbes and microbial-mediated biogeochemical processes depend on animal-induced transport processes (e.g. re-oxidation of particulate reduced sulphur and denitrification, there are indirect hypoxia effects on biogeochemistry via the benthos. Severe long-lasting hypoxia and anoxia may result in the accumulation of reduced compounds in sediments and elimination of macrobenthic communities with the consequences that biogeochemical properties during trajectories of decreasing and increasing oxygen may be different (hysteresis with consequences for coastal ecosystem dynamics.

  6. Mesenchymal Wnt/β-catenin signaling limits tooth number.

    Science.gov (United States)

    Järvinen, Elina; Shimomura-Kuroki, Junko; Balic, Anamaria; Jussila, Maria; Thesleff, Irma

    2018-02-21

    Tooth agenesis is one of the predominant developmental anomalies in humans, usually affecting the permanent dentition generated by sequential tooth formation and, in most cases, caused by mutations perturbing epithelial Wnt/β-catenin signaling. In addition, loss-of-function mutations in the Wnt feedback inhibitor AXIN2 lead to human tooth agenesis. We have investigated the functions of Wnt/β-catenin signaling during sequential formation of molar teeth using mouse models. Continuous initiation of new teeth, which is observed after genetic activation of Wnt/β-catenin signaling in the oral epithelium, was accompanied by enhanced expression of Wnt antagonists and a downregulation of Wnt/β-catenin signaling in the dental mesenchyme. Genetic and pharmacological activation of mesenchymal Wnt/β-catenin signaling negatively regulated sequential tooth formation, an effect partly mediated by Bmp4. Runx2 , a gene whose loss-of-function mutations result in sequential formation of supernumerary teeth in the human cleidocranial dysplasia syndrome, suppressed the expression of Wnt inhibitors Axin2 and Drapc1 in dental mesenchyme. Our data indicate that increased mesenchymal Wnt signaling inhibits the sequential formation of teeth, and suggest that Axin2 / Runx2 antagonistic interactions modulate the level of mesenchymal Wnt/β-catenin signaling, underlying the contrasting dental phenotypes caused by human AXIN2 and RUNX2 mutations. © 2018. Published by The Company of Biologists Ltd.

  7. The Wnt Transcriptional Switch: TLE Removal or Inactivation?

    Science.gov (United States)

    Ramakrishnan, Aravinda-Bharathi; Sinha, Abhishek; Fan, Vinson B; Cadigan, Ken M

    2018-02-01

    Many targets of the Wnt/β-catenin signaling pathway are regulated by TCF transcription factors, which play important roles in animal development, stem cell biology, and oncogenesis. TCFs can regulate Wnt targets through a "transcriptional switch," repressing gene expression in unstimulated cells and promoting transcription upon Wnt signaling. However, it is not clear whether this switch mechanism is a general feature of Wnt gene regulation or limited to a subset of Wnt targets. Co-repressors of the TLE family are known to contribute to the repression of Wnt targets in the absence of signaling, but how they are inactivated or displaced by Wnt signaling is poorly understood. In this mini-review, we discuss several recent reports that address the prevalence and molecular mechanisms of the Wnt transcription switch, including the finding of Wnt-dependent ubiquitination/inactivation of TLEs. Together, these findings highlight the growing complexity of the regulation of gene expression by the Wnt pathway. © 2017 WILEY Periodicals, Inc.

  8. Regulation of Wnt signaling by nociceptive input in animal models

    Directory of Open Access Journals (Sweden)

    Shi Yuqiang

    2012-06-01

    Full Text Available Abstract Background Central sensitization-associated synaptic plasticity in the spinal cord dorsal horn (SCDH critically contributes to the development of chronic pain, but understanding of the underlying molecular pathways is still incomplete. Emerging evidence suggests that Wnt signaling plays a crucial role in regulation of synaptic plasticity. Little is known about the potential function of the Wnt signaling cascades in chronic pain development. Results Fluorescent immunostaining results indicate that β-catenin, an essential protein in the canonical Wnt signaling pathway, is expressed in the superficial layers of the mouse SCDH with enrichment at synapses in lamina II. In addition, Wnt3a, a prototypic Wnt ligand that activates the canonical pathway, is also enriched in the superficial layers. Immunoblotting analysis indicates that both Wnt3a a β-catenin are up-regulated in the SCDH of various mouse pain models created by hind-paw injection of capsaicin, intrathecal (i.t. injection of HIV-gp120 protein or spinal nerve ligation (SNL. Furthermore, Wnt5a, a prototypic Wnt ligand for non-canonical pathways, and its receptor Ror2 are also up-regulated in the SCDH of these models. Conclusion Our results suggest that Wnt signaling pathways are regulated by nociceptive input. The activation of Wnt signaling may regulate the expression of spinal central sensitization during the development of acute and chronic pain.

  9. Efficacy of Wnt-1 monoclonal antibody in sarcoma cells

    International Nuclear Information System (INIS)

    Mikami, Iwao; Koizumi, Kiyoshi; Jablons, David M; You, Liang; He, Biao; Xu, Zhidong; Batra, Sonny; Lee, Amie Y; Mazieres, Julien; Reguart, Noemi; Uematsu, Kazutsugu

    2005-01-01

    Sarcomas are one of the most refractory diseases among malignant tumors. More effective therapies based on an increased understanding of the molecular biology of sarcomas are needed as current forms of therapy remain inadequate. Recently, it has been reported that Wnt-1/β-catenin signaling inhibits apoptosis in several cancers. In this study, we investigated the efficacy of a monoclonal anti-Wnt-1 antibody in sarcoma cells. We treated cell lines A-204, SJSA-1, and fresh primary cultures of lung metastasis of sarcoma with a monoclonal anti-Wnt-1 antibody. Wnt-1 siRNA treatment was carried out in A-204. We assessed cell death using Crystal Violet staining. Apoptosis induction was estimated by flow cytometry analysis (Annexin V and PI staining). Cell signaling changes were determined by western blotting analysis. We detected Wnt-1 expression in all tissue samples and cell lines. Significant apoptosis induction was found in monoclonal anti-Wnt-1 antibody treated cells compared to control monoclonal antibody treated cells (p < 0.02). Similarly, we observed increased apoptosis in Wnt-1 siRNA treated cells. Blockade of Wnt-1 signaling in both experiments was confirmed by analyzing intracellular levels of Dishevelled-3 and of cytosolic β-catenin. Furthermore, the monoclonal anti-Wnt-1 antibody also induced cell death in fresh primary cultures of metastatic sarcoma in which Wnt-1 signaling was active. Our results indicate that Wnt-1 blockade by either monoclonal antibody or siRNA induces cell death in sarcoma cells. These data suggest that Wnt-1 may be a novel therapeutic target for the treatment of a subset of sarcoma cells in which Wnt-1/β-catenin signaling is active

  10. Wnt3a induces the expression of acetylcholinesterase during osteoblast differentiation via the Runx2 transcription factor.

    Science.gov (United States)

    Xu, Miranda L; Bi, Cathy W C; Liu, Etta Y L; Dong, Tina T X; Tsim, Karl W K

    2017-07-28

    Acetylcholinesterase (AChE) hydrolyzes acetylcholine to terminate cholinergic transmission in neurons. Apart from this AChE activity, emerging evidence suggests that AChE could also function in other, non-neuronal cells. For instance, in bone, AChE exists as a proline-rich membrane anchor (PRiMA)-linked globular form in osteoblasts, in which it is proposed to play a noncholinergic role in differentiation. However, this hypothesis is untested. Here, we found that in cultured rat osteoblasts, AChE expression was increased in parallel with osteoblastic differentiation. Because several lines of evidence indicate that AChE activity in osteoblast could be triggered by Wnt/β-catenin signaling, we added recombinant human Wnt3a to cultured osteoblasts and found that this addition induced expression of the ACHE gene and protein product. This Wnt3a-induced AChE expression was blocked by the Wnt-signaling inhibitor Dickkopf protein-1 (DKK-1). We hypothesized that the Runt-related transcription factor 2 (Runx2), a downstream transcription factor in Wnt/β-catenin signaling, is involved in AChE regulation in osteoblasts, confirmed by the identification of a Runx2-binding site in the ACHE gene promoter, further corroborated by ChIP. Of note, Runx2 overexpression in osteoblasts induced AChE expression and activity of the ACHE promoter tagged with the luciferase gene. Moreover, deletion of the Runx2-binding site in the ACHE promoter reduced its activity during osteoblastic differentiation, and addition of 5-azacytidine and trichostatin A to differentiating osteoblasts affected AChE expression, suggesting epigenetic regulation of the ACHE gene. We conclude that AChE plays a role in osteoblastic differentiation and is regulated by both Wnt3a and Runx2. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Expression of WNT genes in cervical cancer-derived cells: Implication of WNT7A in cell proliferation and migration

    International Nuclear Information System (INIS)

    Ramos-Solano, Moisés; Meza-Canales, Ivan D.; Torres-Reyes, Luis A.; Alvarez-Zavala, Monserrat

    2015-01-01

    According to the multifactorial model of cervical cancer (CC) causation, it is now recognized that other modifications, in addition to Human papillomavirus (HPV) infection, are necessary for the development of this neoplasia. Among these, it has been proposed that a dysregulation of the WNT pathway might favor malignant progression of HPV-immortalized keratinocytes. The aim of this study was to identify components of the WNT pathway differentially expressed in CC vs. non-tumorigenic, but immortalized human keratinocytes. Interestingly, WNT7A expression was found strongly downregulated in cell lines and biopsies derived from CC. Restoration of WNT7A in CC-derived cell lines using a lentiviral gene delivery system or after adding a recombinant human protein decreases cell proliferation. Likewise, WNT7A silencing in non-tumorigenic cells markedly accelerates proliferation. Decreased WNT7A expression was due to hypermethylation at particular CpG sites. To our knowledge, this is the first study reporting reduced WNT7A levels in CC-derived cells and that ectopic WNT7A restoration negatively affects cell proliferation and migration. - Highlights: • WNT7A is expressed in normal keratinocytes or cervical cells without lesion. • WNT7A is significantly reduced in cervical cancer-derived cells. • Restoration of WNT7A expression in HeLa decreases proliferation and cell migration. • Silencing of WNT7A in HaCaT induces an increased proliferation and migration rate. • Decreased WNT7A expression in this model is due to hypermethylation

  12. Expression of WNT genes in cervical cancer-derived cells: Implication of WNT7A in cell proliferation and migration

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Solano, Moisés, E-mail: mrsolano84@gmail.com [División de Inmunología, Centro de Investigación Biomédica de Occidente (CIBO)-Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Programa de Doctorado en Ciencias Biomédica, Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara, Jalisco (Mexico); Meza-Canales, Ivan D., E-mail: imezacanales@ice.mpg.de [Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, 07745 Jena (Germany); Torres-Reyes, Luis A., E-mail: torres_reyes_88@hotmail.com [División de Inmunología, Centro de Investigación Biomédica de Occidente (CIBO)-Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Programa de Doctorado en Ciencias Biomédica, Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara, Jalisco (Mexico); Alvarez-Zavala, Monserrat, E-mail: monse_belan@hotmail.com [División de Inmunología, Centro de Investigación Biomédica de Occidente (CIBO)-Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Programa de Doctorado en Ciencias Biomédica, Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara, Jalisco (Mexico); and others

    2015-07-01

    According to the multifactorial model of cervical cancer (CC) causation, it is now recognized that other modifications, in addition to Human papillomavirus (HPV) infection, are necessary for the development of this neoplasia. Among these, it has been proposed that a dysregulation of the WNT pathway might favor malignant progression of HPV-immortalized keratinocytes. The aim of this study was to identify components of the WNT pathway differentially expressed in CC vs. non-tumorigenic, but immortalized human keratinocytes. Interestingly, WNT7A expression was found strongly downregulated in cell lines and biopsies derived from CC. Restoration of WNT7A in CC-derived cell lines using a lentiviral gene delivery system or after adding a recombinant human protein decreases cell proliferation. Likewise, WNT7A silencing in non-tumorigenic cells markedly accelerates proliferation. Decreased WNT7A expression was due to hypermethylation at particular CpG sites. To our knowledge, this is the first study reporting reduced WNT7A levels in CC-derived cells and that ectopic WNT7A restoration negatively affects cell proliferation and migration. - Highlights: • WNT7A is expressed in normal keratinocytes or cervical cells without lesion. • WNT7A is significantly reduced in cervical cancer-derived cells. • Restoration of WNT7A expression in HeLa decreases proliferation and cell migration. • Silencing of WNT7A in HaCaT induces an increased proliferation and migration rate. • Decreased WNT7A expression in this model is due to hypermethylation.

  13. Probing the canonicity of the Wnt/Wingless signaling pathway.

    Directory of Open Access Journals (Sweden)

    Alexandra Franz

    2017-04-01

    Full Text Available The hallmark of canonical Wnt signaling is the transcriptional induction of Wnt target genes by the beta-catenin/TCF complex. Several studies have proposed alternative interaction partners for beta-catenin or TCF, but the relevance of potential bifurcations in the distal Wnt pathway remains unclear. Here we study on a genome-wide scale the requirement for Armadillo (Arm, Drosophila beta-catenin and Pangolin (Pan, Drosophila TCF in the Wnt/Wingless(Wg-induced transcriptional response of Drosophila Kc cells. Using somatic genetics, we demonstrate that both Arm and Pan are absolutely required for mediating activation and repression of target genes. Furthermore, by means of STARR-sequencing we identified Wnt/Wg-responsive enhancer elements and found that all responsive enhancers depend on Pan. Together, our results confirm the dogma of canonical Wnt/Wg signaling and argue against the existence of distal pathway branches in this system.

  14. A SNX3-dependent retromer pathway mediates retrograde transport of the Wnt sorting receptor Wntless and is required for Wnt secretion

    NARCIS (Netherlands)

    Harterink, M.; Port, F.; Lorenowicz, M.J.; McGough, I.J.; Silhankova, M.; Betist, M.C.; van Weering, J.R.; van Heesbeen, R.G.; Middelkoop, T.C.; Basler, K.; Cullen, P.J.; Korswagen, H.C.

    2011-01-01

    Wnt proteins are lipid-modified glycoproteins that play a central role in development, adult tissue homeostasis and disease. Secretion of Wnt proteins is mediated by the Wnt-binding protein Wntless (Wls), which transports Wnt from the Golgi network to the cell surface for release. It has recently

  15. Chronic Intermittent Hypoxia Induces Atherosclerosis

    OpenAIRE

    Savransky, Vladimir; Nanayakkara, Ashika; Li, Jianguo; Bevans, Shannon; Smith, Philip L.; Rodriguez, Annabelle; Polotsky, Vsevolod Y.

    2007-01-01

    Rationale: Obstructive sleep apnea, a condition leading to chronic intermittent hypoxia (CIH), is associated with hyperlipidemia, atherosclerosis, and a high cardiovascular risk. A causal link between obstructive sleep apnea and atherosclerosis has not been established.

  16. Epidural block

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000484.htm Epidural block - pregnancy To use the sharing features on this page, please enable JavaScript. An epidural block is a numbing medicine given by injection (shot) ...

  17. Biliverdin reductase/bilirubin mediates the anti-apoptotic effect of hypoxia in pulmonary arterial smooth muscle cells through ERK1/2 pathway

    International Nuclear Information System (INIS)

    Song, Shasha; Wang, Shuang; Ma, Jun; Yao, Lan; Xing, Hao; Zhang, Lei; Liao, Lin; Zhu, Daling

    2013-01-01

    Inhibition of pulmonary arterial smooth muscle cell (PASMC) apoptosis induced by hypoxia plays an important role in pulmonary arterial remodeling leading to aggravate hypoxic pulmonary arterial hypertension. However, the mechanisms of hypoxia acting on PASMC apoptosis remain exclusive. Biliverdin reductase (BVR) has many essential biologic roles in physiological and pathological processes. Nevertheless, it is unclear whether the hypoxia-induced inhibition on PASMC apoptosis is mediated by BVR. In the present work, we found BVR majorly localized in PASMCs and was up-regulated in levels of protein and mRNA by hypoxia. Then we studied the contribution of BVR to anti-apoptotic response of hypoxia in PASMCs. Our results showed that siBVR, blocking generation of bilirubin, reversed the effect of hypoxia on enhancing cell survival and apoptotic protein (Bcl-2, procasepase-9, procasepase-3) expression, preventing nuclear shrinkage, DNA fragmentation and mitochondrial depolarization in starved PASMCs, which were recovered by exogenous bilirubin. Moreover, the inhibitory effect of bilirubin on PASMC apoptosis under hypoxic condition was blocked by the inhibitor of ERK1/2 pathway. Taken together, our data indicate that BVR contributes to the inhibitory process of hypoxia on PASMC apoptosis, which is mediated by bilirubin through ERK1/2 pathway. Highlights: • BVR expresses in PASMC and is up-regulated by hypoxia in protein and mRNA levels. • BVR/bilirubin contribute to the inhibitive process of hypoxia on PASMC apoptosis. • Bilirubin protects PASMC from apoptosis under hypoxia via ERK1/2 pathway

  18. Biliverdin reductase/bilirubin mediates the anti-apoptotic effect of hypoxia in pulmonary arterial smooth muscle cells through ERK1/2 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Song, Shasha [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Wang, Shuang [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Biopharmaceutical Key Laboratory of Heilongjiang Province, Harbin 150081 (China); Ma, Jun; Yao, Lan; Xing, Hao; Zhang, Lei; Liao, Lin [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Zhu, Daling, E-mail: dalingz@yahoo.com [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Biopharmaceutical Key Laboratory of Heilongjiang Province, Harbin 150081 (China)

    2013-08-01

    Inhibition of pulmonary arterial smooth muscle cell (PASMC) apoptosis induced by hypoxia plays an important role in pulmonary arterial remodeling leading to aggravate hypoxic pulmonary arterial hypertension. However, the mechanisms of hypoxia acting on PASMC apoptosis remain exclusive. Biliverdin reductase (BVR) has many essential biologic roles in physiological and pathological processes. Nevertheless, it is unclear whether the hypoxia-induced inhibition on PASMC apoptosis is mediated by BVR. In the present work, we found BVR majorly localized in PASMCs and was up-regulated in levels of protein and mRNA by hypoxia. Then we studied the contribution of BVR to anti-apoptotic response of hypoxia in PASMCs. Our results showed that siBVR, blocking generation of bilirubin, reversed the effect of hypoxia on enhancing cell survival and apoptotic protein (Bcl-2, procasepase-9, procasepase-3) expression, preventing nuclear shrinkage, DNA fragmentation and mitochondrial depolarization in starved PASMCs, which were recovered by exogenous bilirubin. Moreover, the inhibitory effect of bilirubin on PASMC apoptosis under hypoxic condition was blocked by the inhibitor of ERK1/2 pathway. Taken together, our data indicate that BVR contributes to the inhibitory process of hypoxia on PASMC apoptosis, which is mediated by bilirubin through ERK1/2 pathway. Highlights: • BVR expresses in PASMC and is up-regulated by hypoxia in protein and mRNA levels. • BVR/bilirubin contribute to the inhibitive process of hypoxia on PASMC apoptosis. • Bilirubin protects PASMC from apoptosis under hypoxia via ERK1/2 pathway.

  19. Regulation and regulatory role of WNT signaling in potentiating FSH action during bovine dominant follicle selection.

    Directory of Open Access Journals (Sweden)

    P S P Gupta

    Full Text Available Follicular development occurs in wave like patterns in monotocous species such as cattle and humans and is regulated by a complex interaction of gonadotropins with local intrafollicular regulatory molecules. To further elucidate potential mechanisms controlling dominant follicle selection, granulosa cell RNA harvested from F1 (largest and F2 (second largest follicles isolated at predeviation (PD and onset of diameter deviation (OD stages of the first follicular wave was subjected to preliminary RNA transcriptome analysis. Expression of numerous WNT system components was observed. Hence experiments were performed to test the hypothesis that WNT signaling modulates FSH action on granulosa cells during follicular waves. Abundance of mRNA for WNT pathway members was evaluated in granulosa cells harvested from follicles at emergence (EM, PD, OD and early dominance (ED stages of the first follicular wave. In F1 follicles, abundance of CTNNB1 and DVL1 mRNAs was higher and AXIN2 mRNA was lower at ED versus EM stages and DVL1 and FZD6 mRNAs were higher and AXIN2 mRNA was lower in F1 versus F2 follicle at the ED stage. Bovine granulosa cells were treated in vitro with increasing doses of the WNT inhibitor IWR-1+/- maximal stimulatory dose of FSH. IWR-1 treatment blocked the FSH-induced increase in granulosa cell numbers and reduced the FSH-induced increase in estradiol. Granulosa cells were also cultured in the presence or absence of FSH +/- IWR-1 and hormonal regulation of mRNA for WNT pathway members and known FSH targets determined. FSH treatment increased CYP19A1, CCND2, CTNNB1, AXIN2 and FZD6 mRNAs and the stimulatory effect on CYP19A1 mRNA was reduced by IWR-1. In contrast, FSH reduced CARTPT mRNA and IWR-1 partially reversed the inhibitory effect of FSH. Results support temporal and hormonal regulation and a potential role for WNT signaling in potentiating FSH action during dominant follicle selection.

  20. Crosstalk between Wnt Signaling and RNA Processing in Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Michael Bordonaro

    2013-01-01

    Full Text Available RNA processing involves a variety of processes affecting gene expression, including the removal of introns through RNA splicing, as well as 3' end processing (cleavage and polyadenylation. Alternative RNA processing is fundamentally important for gene regulation, and aberrant processing is associated with the initiation and progression of cancer. Deregulated Wnt signaling, which is the initiating event in the development of most cases of human colorectal cancer (CRC, has been linked to modified RNA processing, which may contribute to Wnt-mediated colonic carcinogenesis. Crosstalk between Wnt signaling and alternative RNA splicing with relevance to CRC includes effects on the expression of Rac1b, an alternatively spliced gene associated with tumorigenesis, which exhibits alternative RNA splicing that is influenced by Wnt activity. In addition, Tcf4, a crucial component of Wnt signaling, also exhibits alternative splicing, which is likely involved in colonic tumorigenesis. Modulation of 3' end formation, including of the Wnt target gene COX-2, also can influence the neoplastic process, with implications for CRC. While many human genes are dependent on introns and splicing for normal levels of gene expression, naturally intronless genes exist with a unique metabolism that allows for intron-independent gene expression. Effects of Wnt activity on the RNA metabolism of the intronless Wnt-target gene c-jun is a likely contributor to cancer development. Further, butyrate, a breakdown product of dietary fiber and a histone deacetylase inhibitor, upregulates Wnt activity in CRC cells, and also modulates RNA processing; therefore, the interplay between Wnt activity, the modulation of this activity by butyrate, and differential RNA metabolism in colonic cells can significantly influence tumorigenesis. Determining the role played by altered RNA processing in Wnt-mediated neoplasia may lead to novel interventions aimed at restoring normal RNA metabolism for

  1. Crosstalk between Wnt Signaling and RNA Processing in Colorectal Cancer.

    Science.gov (United States)

    Bordonaro, Michael

    2013-01-01

    RNA processing involves a variety of processes affecting gene expression, including the removal of introns through RNA splicing, as well as 3' end processing (cleavage and polyadenylation). Alternative RNA processing is fundamentally important for gene regulation, and aberrant processing is associated with the initiation and progression of cancer. Deregulated Wnt signaling, which is the initiating event in the development of most cases of human colorectal cancer (CRC), has been linked to modified RNA processing, which may contribute to Wnt-mediated colonic carcinogenesis. Crosstalk between Wnt signaling and alternative RNA splicing with relevance to CRC includes effects on the expression of Rac1b, an alternatively spliced gene associated with tumorigenesis, which exhibits alternative RNA splicing that is influenced by Wnt activity. In addition, Tcf4, a crucial component of Wnt signaling, also exhibits alternative splicing, which is likely involved in colonic tumorigenesis. Modulation of 3' end formation, including of the Wnt target gene COX-2, also can influence the neoplastic process, with implications for CRC. While many human genes are dependent on introns and splicing for normal levels of gene expression, naturally intronless genes exist with a unique metabolism that allows for intron-independent gene expression. Effects of Wnt activity on the RNA metabolism of the intronless Wnt-target gene c-jun is a likely contributor to cancer development. Further, butyrate, a breakdown product of dietary fiber and a histone deacetylase inhibitor, upregulates Wnt activity in CRC cells, and also modulates RNA processing; therefore, the interplay between Wnt activity, the modulation of this activity by butyrate, and differential RNA metabolism in colonic cells can significantly influence tumorigenesis. Determining the role played by altered RNA processing in Wnt-mediated neoplasia may lead to novel interventions aimed at restoring normal RNA metabolism for therapeutic benefit

  2. Effect of low-frequency low-intensity ultrasound with microbubbles on prostate cancer hypoxia.

    Science.gov (United States)

    Hou, Rui; Xu, Yanjun; Lu, Qijie; Zhang, Yang; Hu, Bing

    2017-10-01

    Angiogenesis plays an important role in tumor growth, invasiveness, and metastasis. It is well established that prostate cancer is exposed to fluctuating oxygen tensions and both acute and chronic hypoxia exist, and these conditions can upregulate angiogenesis-associated proteins such as hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A. Low-frequency low-intensity ultrasound with microbubbles can induce obvious microvessel damage in tumors, cause cell necrosis or apoptosis. However, there is no information about whether the blocking blood effect of low-frequency low-intensity ultrasound with microbubbles has an influence on hypoxia environment of prostate cancer. Therefore, we investigated the impact of different low-frequency low-intensity ultrasound with microbubbles radiation times on prostate tumors, observed the change in the hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A protein levels, as well as cell proliferation, apoptosis, and tumor volume. The results indicated that as the radiation was repeated four times on each treatment day, the effects of interruption were durable, the cell proliferation was inhibited, and apoptosis was promoted, and the hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A expression levels were lower in the treatment group than in the control group. When the radiation was carried out once per treatment day, the hypoxia response was stimulated, the hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A expression levels were higher compared with the control group, and cell proliferation was promoted. In addition, the tumor volume increased obviously in the hypoxia-stimulated group, whereas tumors grew slowly in the hypoxia-suppressed group. The results of this work demonstrated that under the same conditions, different radiation times of low-frequency low-intensity ultrasound with microbubbles affect the hypoxia response differently, and the

  3. Chronic hypoxia promotes pulmonary artery endothelial cell proliferation through H2O2-induced 5-lipoxygenase.

    Directory of Open Access Journals (Sweden)

    Kristi M Porter

    Full Text Available Pulmonary Hypertension (PH is a progressive disorder characterized by endothelial dysfunction and proliferation. Hypoxia induces PH by increasing vascular remodeling. A potential mediator in hypoxia-induced PH development is arachidonate 5-Lipoxygenase (ALOX5. While ALOX5 metabolites have been shown to promote pulmonary vasoconstriction and endothelial cell proliferation, the contribution of ALOX5 to hypoxia-induced proliferation remains unknown. We hypothesize that hypoxia exposure stimulates HPAEC proliferation by increasing ALOX5 expression and activity. To test this, human pulmonary artery endothelial cells (HPAEC were cultured under normoxic (21% O2 or hypoxic (1% O2 conditions for 24-, 48-, or 72 hours. In a subset of cells, the ALOX5 inhibitor, zileuton, or the 5-lipoxygenase activating protein inhibitor, MK-886, was administered during hypoxia exposure. ALOX5 expression was measured by qRT-PCR and western blot and HPAEC proliferation was assessed. Our results demonstrate that 24 and 48 hours of hypoxia exposure have no effect on HPAEC proliferation or ALOX5 expression. Seventy two hours of hypoxia significantly increases HPAEC ALOX5 expression, hydrogen peroxide (H2O2 release, and HPAEC proliferation. We also demonstrate that targeted ALOX5 gene silencing or inhibition of the ALOX5 pathway by pharmacological blockade attenuates hypoxia-induced HPAEC proliferation. Furthermore, our findings indicate that hypoxia-induced increases in cell proliferation and ALOX5 expression are dependent on H2O2 production, as administration of the antioxidant PEG-catalase blocks these effects and addition of H2O2 to HPAEC promotes proliferation. Overall, these studies indicate that hypoxia exposure induces HPAEC proliferation by activating the ALOX5 pathway via the generation of H2O2.

  4. Population Blocks.

    Science.gov (United States)

    Smith, Martin H.

    1992-01-01

    Describes an educational game called "Population Blocks" that is designed to illustrate the concept of exponential growth of the human population and some potential effects of overpopulation. The game material consists of wooden blocks; 18 blocks are painted green (representing land), 7 are painted blue (representing water); and the remaining…

  5. Hypoxia, Oxidative Stress and Fat

    Directory of Open Access Journals (Sweden)

    Nikolaus Netzer

    2015-06-01

    Full Text Available Metabolic disturbances in white adipose tissue in obese individuals contribute to the pathogenesis of insulin resistance and the development of type 2 diabetes mellitus. Impaired insulin action in adipocytes is associated with elevated lipolysis and increased free fatty acids leading to ectopic fat deposition in liver and skeletal muscle. Chronic adipose tissue hypoxia has been suggested to be part of pathomechanisms causing dysfunction of adipocytes. Hypoxia can provoke oxidative stress in human and animal adipocytes and reduce the production of beneficial adipokines, such as adiponectin. However, time-dose responses to hypoxia relativize the effects of hypoxic stress. Long-term exposure of fat cells to hypoxia can lead to the production of beneficial substances such as leptin. Knowledge of time-dose responses of hypoxia on white adipose tissue and the time course of generation of oxidative stress in adipocytes is still scarce. This paper reviews the potential links between adipose tissue hypoxia, oxidative stress, mitochondrial dysfunction, and low-grade inflammation caused by adipocyte hypertrophy, macrophage infiltration and production of inflammatory mediators.

  6. Antagonism between Hedgehog and Wnt signaling pathways regulates tumorigenicity.

    Science.gov (United States)

    Ding, Mei; Wang, Xin

    2017-12-01

    The crosstalk of multiple cellular signaling pathways is crucial in animal development and tissue homeostasis, and its dysregulation may result in tumor formation and metastasis. The Hedgehog (Hh) and Wnt signaling pathways are both considered to be essential regulators of cell proliferation, differentiation and oncogenesis. Recent studies have indicated that the Hh and Wnt signaling pathways are closely associated and involved in regulating embryogenesis and cellular differentiation. Hh signaling acts upstream of the Wnt signaling pathway, and negative regulates Wnt activity via secreted frizzled-related protein 1 (SFRP1), and the Wnt/β-catenin pathway downregulates Hh activity through glioma-associated oncogene homolog 3 transcriptional regulation. This evidence suggests that the imbalance of Hh and Wnt regulation serves a crucial role in cancer-associated processes. The activation of SFRP1, which inhibits Wnt, has been demonstrated to be an important cross-point between the two signaling pathways. The present study reviews the complex interaction between the Hh and Wnt signaling pathways in embryogenesis and tumorigenicity, and the role of SFRP1 as an important mediator associated with the dysregulation of the Hh and Wnt signaling pathways.

  7. Exposure to febrile-range hyperthermia potentiates Wnt signalling and epithelial-mesenchymal transition gene expression in lung epithelium.

    Science.gov (United States)

    Potla, Ratnakar; Tulapurkar, Mohan E; Luzina, Irina G; Atamas, Sergei P; Singh, Ishwar S; Hasday, Jeffrey D

    2018-02-01

    As environmental and body temperatures vary, lung epithelial cells experience temperatures significantly different from normal core temperature. Our previous studies in human lung epithelium showed that: (i) heat shock accelerates wound healing and activates profibrotic gene expression through heat shock factor-1 (HSF1); (ii) HSF1 is activated at febrile temperatures (38-41 °C) and (iii) hypothermia (32 °C) activates and hyperthermia (39.5 °C) reduces expression of a subset of miRNAs that target protein kinase-Cα (PKCα) and enhance proliferation. We analysed the effect of hypo- and hyperthermia exposure on Wnt signalling by exposing human small airway epithelial cells (SAECs) and HEK293T cells to 32, 37 or 39.5 °C for 24 h, then analysing Wnt-3a-induced epithelial-mesenchymal transition (EMT) gene expression by qRT-PCR and TOPFlash reporter plasmid activity. Effects of miRNA mimics and inhibitors and the HSF1 inhibitor, KNK437, were evaluated. Exposure to 39.5 °C for 24 h increased subsequent Wnt-3a-induced EMT gene expression in SAECs and Wnt-3a-induced TOPFlash activity in HEK293T cells. Increased Wnt responsiveness was associated with HSF1 activation and blocked by KNK437. Overexpressing temperature-responsive miRNA mimics reduced Wnt responsiveness in 39.5 °C-exposed HEK293T cells, but inhibitors of the same miRNAs failed to restore Wnt responsiveness in 32 °C-exposed HEK293T cells. Wnt responsiveness, including expression of genes associated with EMT, increases after exposure to febrile-range temperature through an HSF1-dependent mechanism that is independent of previously identified temperature-dependent miRNAs. This process may be relevant to febrile fibrosing lung diseases, including the fibroproliferative phase of acute respiratory distress syndrome (ARDS) and exacerbations of idiopathic pulmonary fibrosis (IPF).

  8. Linc00210 drives Wnt/β-catenin signaling activation and liver tumor progression through CTNNBIP1-dependent manner.

    Science.gov (United States)

    Fu, Xiaomin; Zhu, Xiaoyan; Qin, Fujun; Zhang, Yong; Lin, Jizhen; Ding, Yuechao; Yang, Zihe; Shang, Yiman; Wang, Li; Zhang, Qinxian; Gao, Quanli

    2018-03-14

    Liver tumor initiating cells (TICs) have self-renewal and differentiation properties, accounting for tumor initiation, metastasis and drug resistance. Long noncoding RNAs are involved in many physiological and pathological processes, including tumorigenesis. DNA copy number alterations (CNA) participate in tumor formation and progression, while the CNA of lncRNAs and their roles are largely unknown. LncRNA CNA was determined by microarray analyses, realtime PCR and DNA FISH. Liver TICs were enriched by surface marker CD133 and oncosphere formation. TIC self-renewal was analyzed by oncosphere formation, tumor initiation and propagation. CRISPRi and ASO were used for lncRNA loss of function. RNA pulldown, western blot and double FISH were used to identify the interaction between lncRNA and CTNNBIP1. Using transcriptome microarray analysis, we identified a frequently amplified long noncoding RNA in liver cancer termed linc00210, which was highly expressed in liver cancer and liver TICs. Linc00210 copy number gain is associated with its high expression in liver cancer and liver TICs. Linc00210 promoted self-renewal and tumor initiating capacity of liver TICs through Wnt/β-catenin signaling. Linc00210 interacted with CTNNBIP1 and blocked its inhibitory role in Wnt/β-catenin activation. Linc00210 silencing cells showed enhanced interaction of β-catenin and CTNNBIP1, and impaired interaction of β-catenin and TCF/LEF components. We also confirmed linc00210 copy number gain using primary hepatocellular carcinoma (HCC) samples, and found the correlation between linc00210 CNA and Wnt/β-catenin activation. Of interest, linc00210, CTNNBIP1 and Wnt/β-catenin signaling targeting can efficiently inhibit tumor growth and progression, and liver TIC propagation. With copy-number gain in liver TICs, linc00210 is highly expressed along with liver tumorigenesis. Linc00210 drives the self-renewal and propagation of liver TICs through activating Wnt/β-catenin signaling. Linc00210

  9. Osteoclast TGF-β Receptor Signaling Induces Wnt1 Secretion and Couples Bone Resorption to Bone Formation

    Science.gov (United States)

    Weivoda, Megan M; Ruan, Ming; Pederson, Larry; Hachfeld, Christine; Davey, Rachel A; Zajac, Jeffrey D; Westendorf, Jennifer J; Khosla, Sundeep; Oursler, Merry Jo

    2016-01-01

    Osteoblast-mediated bone formation is coupled to osteoclast-mediated bone resorption. These processes become uncoupled with age, leading to increased risk for debilitating fractures. Therefore, understanding how osteoblasts are recruited to sites of resorption is vital to treating age-related bone loss. Osteoclasts release and activate TGF-β from the bone matrix. Here we show that osteoclastspecific inhibition of TGF-β receptor signaling in mice results in osteopenia due to reduced osteoblast numbers with no significant impact on osteoclast numbers or activity. TGF-β induced osteoclast expression of Wnt1, a protein crucial to normal bone formation, and this response was blocked by impaired TGF-β receptor signaling. Osteoclasts in aged murine bones had lower TGF-β signaling and Wnt1 expression in vivo. Ex vivo stimulation of osteoclasts derived from young or old mouse bone marrow macrophages showed no difference in TGF-β–induced Wnt1 expression. However, young osteoclasts expressed reduced Wnt1 when cultured on aged mouse bone chips compared to young mouse bone chips, consistent with decreased skeletal TGF-β availability with age. Therefore, osteoclast responses to TGF-β are essential for coupling bone resorption to bone formation, and modulating this pathway may provide opportunities to treat age-related bone loss. PMID:26108893

  10. HIF1 Contributes to Hypoxia-Induced Pancreatic Cancer Cells Invasion via Promoting QSOX1 Expression

    Directory of Open Access Journals (Sweden)

    Chen-Ye Shi

    2013-08-01

    Full Text Available Background: Quiescin sulfhydryl oxidase 1 (QSOX1, which oxidizes sulfhydryl groups to form disulfide bonds in proteins, is found to be over-expressed in various pancreatic cancer cell lines and patients. QSOX1 promotes invasion of pancreatic cancer cells by activating MMP-2 and MMP-9. However, its regulatory mechanism remains largely undefined. Methods: Real-time PCR and Western blot were employed to detect the expression of QSOX1 in human pancreatic cancer cell lines under hypoxic condition. Luciferase reporter and ChIP assays were used to assess the regulation of QSOX1 by hypoxia-inducible factor 1 (HIF-1. Small interfering RNA (siRNA was applied to knock down endogenous expression of QSOX1. Matrigel-coated invasion chamber essays were conducted to detect the invasion capacity of QSOX1-depleted cells. Results: Both hypoxia and hypoxia mimicking reagent up-regulated the expression of QSOX1 in human pancreatic cancer cell lines. Knockdown of HIF-1α eliminated hypoxia induced QSOX1 expression. HIF-1α was found directly bound to two hypoxia-response elements (HRE of QSOX1 gene, both of which were required for HIF-1 induced QSOX1 expression. Moreover, QSOX1 silencing blocked hypoxia-induced pancreatic cancer cells invasion. Conclusion: QSOX1 is a direct target of HIF-1 and may contribute to hypoxia-induced pancreatic cancer cells invasion.

  11. Low Molecular Weight Fucoidan Inhibits Tumor Angiogenesis through Downregulation of HIF-1/VEGF Signaling under Hypoxia

    Directory of Open Access Journals (Sweden)

    Meng-Chuan Chen

    2015-07-01

    Full Text Available Activation of hypoxia-induced hypoxia-inducible factors-1 (HIF-1 plays a critical role in promoting tumor angiogenesis, growth and metastasis. Low molecular weight fucoidan (LMWF is prepared from brown algae, and exhibits anticancer activity. However, whether LMWF attenuates hypoxia-induced angiogenesis in bladder cancer cells and the molecular mechanisms involved remain unclear. This is the first study to demonstrate that LMWF can inhibit hypoxia-stimulated H2O2 formation, HIF-1 accumulation and transcriptional activity vascular endothelial growth factor (VEGF secretion, and the migration and invasion in hypoxic human bladder cancer cells (T24 cells. LMWF also downregulated hypoxia-activated phosphorylation of PI3K/AKT/mTOR/p70S6K/4EBP-1 signaling in T24 cells. Blocking PI3K/AKT or mTOR activity strongly diminished hypoxia-induced HIF-1α expression and VEGF secretion in T24 cells, supporting the involvement of PI3K/AKT/mTOR in the induction of HIF-1α and VEGF. Additionally, LMWF significantly attenuated angiogenesis in vitro and in vivo evidenced by reduction of tube formation of hypoxic human umbilical vascular endothelial cells and blood capillary generation in the tumor. Similarly, administration of LMWF also inhibited the HIF-1α and VEGF expression in vivo, accompanied by a reduction of tumor growth. In summary, under hypoxia conditions, the antiangiogenic activity of LMWF in bladder cancer may be associated with suppressing HIF-1/VEGF-regulated signaling pathway.

  12. Functional Wnt signaling is increased in idiopathic pulmonary fibrosis.

    Directory of Open Access Journals (Sweden)

    Melanie Königshoff

    Full Text Available BACKGROUND: Idiopathic pulmonary fibrosis (IPF is a fatal lung disease, characterized by distorted lung architecture and loss of respiratory function. Alveolar epithelial cell injury and hyperplasia, enhanced extracellular matrix deposition, and (myofibroblast activation are features of IPF. Wnt/beta-catenin signaling has been shown to determine epithelial cell fate during development. As aberrant reactivation of developmental signaling pathways has been suggested to contribute to IPF pathogenesis, we hypothesized that Wnt/beta-catenin signaling is activated in epithelial cells in IPF. Thus, we quantified and localized the expression and activity of the Wnt/beta-catenin pathway in IPF. METHODOLOGY/PRINCIPAL FINDINGS: The expression of Wnt1, 3a, 7b, and 10b, the Wnt receptors Fzd1-4, Lrp5-6, as well as the intracellular signal transducers Gsk-3beta, beta-catenin, Tcf1, 3, 4, and Lef1 was analyzed in IPF and transplant donor lungs by quantitative real-time (qRT-PCR. Wnt1, 7b and 10b, Fzd2 and 3, beta-catenin, and Lef1 expression was significantly increased in IPF. Immunohistochemical analysis localized Wnt1, Wnt3a, beta-catenin, and Gsk-3beta expression largely to alveolar and bronchial epithelium. This was confirmed by qRT-PCR of primary alveolar epithelial type II (ATII cells, demonstrating a significant increase of Wnt signaling in ATII cells derived from IPF patients. In addition, Western blot analysis of phospho-Gsk-3beta, phospho-Lrp6, and beta-catenin, and qRT-PCR of the Wnt target genes cyclin D1, Mmp 7, or Fibronectin 1 demonstrated increased functional Wnt/beta-catenin signaling in IPF compared with controls. Functional in vitro studies further revealed that Wnt ligands induced lung epithelial cell proliferation and (myofibroblast activation and collagen synthesis. CONCLUSIONS/SIGNIFICANCE: Our study demonstrates that the Wnt/beta-catenin pathway is expressed and operative in adult lung epithelium. Increased Wnt/beta-catenin signaling

  13. Nitroimidazoles and imaging hypoxia

    International Nuclear Information System (INIS)

    Nunn, A.; Linder, K.; Strauss, H.W.

    1995-01-01

    A class of compounds known to undergo different intracellular metabolism depending on the availability of oxygen in tissue, the nitroimidazoles, have been advocated for imaging hypoxic tissue. In the presence of normal oxygen levels the molecule is immediately reoxidized. In hypoxic tissue the low oxygen concentration is not able to effectively compete to reoxidize the molecule and further reduction appears to take place. The association is not irreversible. Nitroimidazoles for in vivo imaging using radiohalogenated derivatives of misonidazole have recently been employed in patients. Two major problems with fluoromisonidazole are its relatively low concentration within the lesion and the need to wait several hours to permit clearance of the agent from the normoxic background tissue. Even with high-resolution positron emission tomographic imaging, this combination of circumstances makes successful evaluation of hypoxic lesions a challenge. Single-photon agents, with their longer half-lives and comparable biological properties, offer a greater opportunity for successful imaging. In 1992 technetium-99m labeled nitroimidazoles were described that seem to have at least comparable in vivo characteristics. Laboratory studies have demonstrated preferential binding of these agents to hypoxic tissue in the myocardium, in the brain, and in tumors. These investigations indicate that imaging can provide direct evidence of tissue with low oxygen levels that is viable. Even from this early vantage point the utility of measuring tissue oxygen levels with external imaging suggests that hypoxia imaging could play a major role in clinical decision making. (orig./MG)

  14. Wnt pathway in Dupuytren disease: connecting profibrotic signals.

    Science.gov (United States)

    van Beuge, Marike M; Ten Dam, Evert-Jan P M; Werker, Paul M N; Bank, Ruud A

    2015-12-01

    A role of Wnt signaling in Dupuytren disease, a fibroproliferative disease of the hand and fingers, has not been fully elucidated. We examined a large set of Wnt pathway components and signaling targets and found significant dysregulation of 41 Wnt-related genes in tissue from the Dupuytren nodules compared with patient-matched control tissue. A large proportion of genes coding for Wnt proteins themselves was downregulated. However, both canonical Wnt targets and components of the noncanonical signaling pathway were upregulated. Immunohistochemical analysis revealed that protein expression of Wnt1-inducible secreted protein 1 (WISP1), a known Wnt target, was increased in nodules compared with control tissue, but knockdown of WISP1 using small interfering RNA (siRNA) in the Dupuytren myofibroblasts did not confirm a functional role. The protein expression of noncanonical pathway components Wnt5A and VANGL2 as well as noncanonical coreceptors Ror2 and Ryk was increased in nodules. On the contrary, the strongest downregulated genes in this study were 4 antagonists of Wnt signaling (DKK1, FRZB, SFRP1, and WIF1). Downregulation of these genes in the Dupuytren tissue was mimicked in vitro by treating normal fibroblasts with transforming growth factor β1 (TGF-β1), suggesting cross talk between different profibrotic pathways. Furthermore, siRNA-mediated knockdown of these antagonists in normal fibroblasts led to increased nuclear translocation of Wnt target β-catenin in response to TGF-β1 treatment. In conclusion, we have shown extensive dysregulation of Wnt signaling in affected tissue from Dupuytren disease patients. Components of both the canonical and the noncanonical pathways are upregulated, whereas endogenous antagonists are downregulated, possibly via interaction with other profibrotic pathways. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Hypoxia-inducible factor-1α upregulation in microglia following hypoxia protects against ischemia-induced cerebral infarction.

    Science.gov (United States)

    Huang, Tao; Huang, Weiyi; Zhang, Zhiqiang; Yu, Lei; Xie, Caijun; Zhu, Dongan; Peng, Zizhuang; Chen, Jiehan

    2014-10-01

    Activated microglia were considered to be the toxic inflammatory mediators that induce neuron degeneration after brain ischemia. Hypoxia can enhance the expression of hypoxia-inducible factor-1α (HIF-1α) in microglia and cause microglial activation. However, intermittent hypoxia has been reported recently to be capable of protecting the body from myocardial ischemia. We established a high-altitude environment as the hypoxic condition in this study. The hypoxic condition displayed a neuroprotective effect after brain ischemia, and mice exposed to this condition presented better neurological performance and smaller infarct size. At the same time, a high level of HIF-1α, low level of isoform of nitric oxide synthase, and a reduction in microglial activation were also seen in ischemic focus of hypoxic mice. However, this neuroprotective effect could be blocked by 2-methoxyestradiol, the HIF-1α inhibitor. Our finding suggested that HIF-1α expression was involved in microglial activation in vitro and was regulated by oxygen supply. The microglia were inactivated by re-exposure to hypoxia, which might be due to overexpression of HIF-1α. These results indicated that hypoxic conditions can be exploited to achieve maximum neuroprotection after brain ischemia. This mechanism possibly lies in microglial inactivation through regulation of the expression of HIF-1α.

  16. Smad, PI3K/Akt, and Wnt-dependent signaling pathways are involved in BMP-4-induced ESC self-renewal.

    Science.gov (United States)

    Lee, Min Young; Lim, Hyun Woo; Lee, Sang Hun; Han, Ho Jae

    2009-08-01

    It is known that bone morphogenetic protein 4 (BMP-4) has a diverse effect on ESCs. However, its precise mechanism in mouse ESCs is not fully understood. We evaluated the effect of BMP-4 on ESC proliferation and its related signal cascades in this study. BMP-4 significantly increased the level of [(3)H]-thymidine incorporation in time- (> or =8 hours) and dose- (> or =10 ng/ml) dependent manners. Additionally, BMP-4 increased cyclin D1 and decreased p27(kip1) expression values in a time-dependent manner. The increases in BMP-4-induced [(3)H]-thymidine incorporation and cyclin D1 expression were inhibited by the BMP-4 receptor antagonist noggin. BMP-4 increased Wnt1 expression. Wnt1 expression was attenuated by Smad4 small interfering RNA (siRNA), and BMP-4-induced cyclin D1 expression was inhibited by Smad4 and Wnt1 siRNAs. BMP-4 also activated beta-catenin, which was blocked by Smad4 and Wnt1 siRNAs. In addition, BMP-4 induced Akt phosphorylation. BMP-4-induced beta-catenin activation and cyclin D1 expression were attenuated by phosphatidyl inositol 3-kinase (PI3K) siRNA and Akt inhibitor. Additionally, downregulation of Smad4, Wnt1, and PI3K expression by siRNA decreased the levels of pluripotency marker mRNAs of ESCs, including Oct4, Sox2, and FoxD3. Our results suggested that BMP-4-induced [(3)H]-thymidine incorporation was significantly attenuated by Smad4, Wnt1, and PI3K knockdown. In conclusion, BMP-4 contributed to the maintenance of cell proliferation and the pluripotent state by Smad, PI3K/Akt, and Wnt1/beta-catenin in mouse ESCs.

  17. Wnt signaling in the intestinal epithelium: from endoderm to cancer.

    NARCIS (Netherlands)

    Gregorieff, A.; Clevers, J.C.

    2005-01-01

    The Wnt pathway controls cell fate during embryonic development. It also persists as a key regulator of homeostasis in adult self-renewing tissues. In these tissues, mutational deregulation of the Wnt cascade is closely associated with malignant transformation. The intestinal epithelium represents

  18. ERAD-dependent control of the Wnt secretory factor Evi.

    Science.gov (United States)

    Glaeser, Kathrin; Urban, Manuela; Fenech, Emma; Voloshanenko, Oksana; Kranz, Dominique; Lari, Federica; Christianson, John C; Boutros, Michael

    2018-02-15

    Active regulation of protein abundance is an essential strategy to modulate cellular signaling pathways. Within the Wnt signaling cascade, regulated degradation of β-catenin by the ubiquitin-proteasome system (UPS) affects the outcome of canonical Wnt signaling. Here, we found that abundance of the Wnt cargo receptor Evi (Wls/GPR177), which is required for Wnt protein secretion, is also regulated by the UPS through endoplasmic reticulum (ER)-associated degradation (ERAD). In the absence of Wnt ligands, Evi is ubiquitinated and targeted for ERAD in a VCP-dependent manner. Ubiquitination of Evi involves the E2-conjugating enzyme UBE2J2 and the E3-ligase CGRRF1. Furthermore, we show that a triaging complex of Porcn and VCP determines whether Evi enters the secretory or the ERAD pathway. In this way, ERAD-dependent control of Evi availability impacts the scale of Wnt protein secretion by adjusting the amount of Evi to meet the requirement of Wnt protein export. As Wnt and Evi protein levels are often dysregulated in cancer, targeting regulatory ERAD components might be a useful approach for therapeutic interventions. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

  19. Non-conventional Frizzled ligands and Wnt receptors.

    Science.gov (United States)

    Hendrickx, Marijke; Leyns, Luc

    2008-05-01

    The Wnt family of secreted signaling factors plays numerous roles in embryonic development and in stem cell biology. In the adult, Wnt signaling is involved in tissue homeostasis and mutations that lead to the overexpression of Wnt can be linked to cancer. Wnt signaling is transduced intracellularly by the Frizzled (Fzd) family of receptors. In the canonical pathway, accumulation of beta-catenin and the subsequent formation of a complex with T cell factors (TCF) or lymphoid enhancing factors (Lef) lead to target gene activation. The identification of Ryk as an alternative Wnt receptor and the discovery of the novel Fzd ligands Norrie disease protein (NDP) and R-Spondin, changed the traditional view of Wnts binding to Fzd receptors. Mouse R-Spondin cooperates with Wnt signaling and Low density lipoprotein (LDL) receptor related protein (LRP) to activate beta-catenin dependent gene expression and is involved in processes such as limb and placental development in the mouse. NDP is the product of the Norrie disease gene and controls vascular development in the retina, inner ear and in the female reproductive system during pregnancy. In this review a functional overview of the interactions of the different Wnt and non-Wnt ligands with the Fzd receptors is given as well as a survey of Wnts binding to Ryk and we discuss the biological significance of these interactions.

  20. Physiological determinants of human acute hypoxia tolerance.

    Science.gov (United States)

    2013-11-01

    AbstractIntroduction. We investigated possible physiological determinants of variability in hypoxia tolerance in subjects given a 5-minute normobaric exposure to 25,000 ft equivalent. Physiological tolerance to hypoxia was defined as the magnitude of...

  1. Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation.

    Directory of Open Access Journals (Sweden)

    Laura Asnaghi

    Full Text Available The transcriptional response promoted by hypoxia-inducible factors has been associated with metastatic spread of uveal melanoma. We found expression of hypoxia-inducible factor 1α (HIF-1α protein in well-vascularized tumor regions as well as in four cell lines grown in normoxia, thus this pathway may be important even in well-oxygenated uveal melanoma cells. HIF-1α protein accumulation in normoxia was inhibited by rapamycin. As expected, hypoxia (1% pO2 further induced HIF-1α protein levels along with its target genes VEGF and LOX. Growth in hypoxia significantly increased cellular invasion of all 5 uveal melanoma lines tested, as did the introduction of an oxygen-insensitive HIF-1α mutant into Mel285 cells with low HIF-1α baseline levels. In contrast, HIF-1α knockdown using shRNA significantly decreased growth in hypoxia, and reduced by more than 50% tumor invasion in four lines with high HIF-1α baseline levels. Pharmacologic blockade of HIF-1α protein expression using digoxin dramatically suppressed cellular invasion both in normoxia and in hypoxia. We found that Notch pathway components, including Jag1-2 ligands, Hes1-Hey1 targets and the intracellular domain of Notch1, were increased in hypoxia, as well as the phosphorylation levels of Erk1-2 and Akt. Pharmacologic and genetic inhibition of Notch largely blocked the hypoxic induction of invasion as did the pharmacologic suppression of Erk1-2 activity. In addition, the increase in Erk1-2 and Akt phosphorylation by hypoxia was partially reduced by inhibiting Notch signaling. Our findings support the functional importance of HIF-1α signaling in promoting the invasive capacity of uveal melanoma cells in both hypoxia and normoxia, and suggest that pharmacologically targeting HIF-1α pathway directly or through blockade of Notch or Erk1-2 pathways can slow tumor spread.

  2. Wnt/β-catenin signaling activates nephronectin expression in osteoblasts

    International Nuclear Information System (INIS)

    Ikehata, Mikiko; Yamada, Atsushi; Morimura, Naoko; Itose, Masakatsu; Suzawa, Tetsuo; Shirota, Tatsuo; Chikazu, Daichi; Kamijo, Ryutaro

    2017-01-01

    Nephronectin (Npnt), an extracellular matrix protein, is considered to play critical roles as an adhesion molecule in the development and functions of various organs and tissues, such as the kidneys and bone. In the present study, we found that Wnt3a strongly enhanced Npnt mRNA expression in osteoblast-like MC3T3-E1 cells, while it also induced an increase in Npnt gene expression in both time- and dose-dependent manners via the Wnt/β-catenin signaling pathway. These results suggest novel mechanisms for Wnt3a-induced osteoblast proliferation and cell survival via Npnt gene expression. - Highlights: • Wnt3a enhances nephronectin gene expression. • Nephronectin gene induction by Wnt3a is occurred by time- and dose-dependent manner. • Expression of nephronectin is regulated via β-catenin activation.

  3. Wnt Signaling Is Required for Long-Term Memory Formation

    Directory of Open Access Journals (Sweden)

    Ying Tan

    2013-09-01

    Full Text Available Wnt signaling regulates synaptic plasticity and neurogenesis in the adult nervous system, suggesting a potential role in behavioral processes. Here, we probed the requirement for Wnt signaling during olfactory memory formation in Drosophila using an inducible RNAi approach. Interfering with β-catenin expression in adult mushroom body neurons specifically impaired long-term memory (LTM without altering short-term memory. The impairment was reversible, being rescued by expression of a wild-type β-catenin transgene, and correlated with disruption of a cellular LTM trace. Inhibition of wingless, a Wnt ligand, and arrow, a Wnt coreceptor, also impaired LTM. Wingless expression in wild-type flies was transiently elevated in the brain after LTM conditioning. Thus, inhibiting three key components of the Wnt signaling pathway in adult mushroom bodies impairs LTM, indicating that this pathway mechanistically underlies this specific form of memory.

  4. WNT2B2 mRNA, up-regulated in primary gastric cancer, is a positive regulator of the WNT- beta-catenin-TCF signaling pathway.

    Science.gov (United States)

    Katoh, M; Kirikoshi, H; Terasaki, H; Shiokawa, K

    2001-12-21

    Genetic alterations of WNT signaling molecules lead to carcinogenesis through activation of the beta-catenin-TCF signaling pathway. We have previously cloned and characterized WNT2B/WNT13 gene on human chromosome 1p13, which is homologous to proto-oncogene WNT2 on human chromosome 7q31. WNT2B1 and WNT2B2 mRNAs, generated from the WNT2B gene due to alternative splicing of the alternative promoter type, encode almost identical polypeptides with divergence in the N-terminal region. WNT2B2 mRNA rather than WNT2B1 mRNA is preferentially expressed in NT2 cells with the potential of neuronal differentiation. Here, we describe our investigations of expression of WNT2B mRNAs in various types of human primary cancer. Matched tumor/normal expression array analysis revealed that WNT2B mRNAs were significantly up-regulated in 2 of 8 cases of primary gastric cancer. WNT2B2 mRNA rather than WNT2B1 mRNA was found to be preferentially up-regulated in a case of primary gastric cancer (signet ring cell carcinoma). Function of WNT2B1 mRNA and that of WNT2B2 mRNA were investigated by using Xenopus axis duplication assay. Injection of synthetic WNT2B1 mRNA into the ventral marginal zone of fertilized Xenopus eggs at the 4-cell stage did not induce axis duplication. In contrast, ventral injection of synthetic WNT2B2 mRNA induced axis duplication in 90% of embryos (complete axis duplication, 24%). These results strongly suggest that WNT2B2 up-regulation in some cases of gastric cancer might lead to carcinogenesis through activation of the beta-catenin-TCF signaling pathway.

  5. Teleosts in hypoxia : Aspects of anaerobic metabolism

    NARCIS (Netherlands)

    Van den Thillart, G.; van Waarde, Aren

    1985-01-01

    Moderate hypoxia can be tolerated by many fish species, while only some species survive severe hypoxia or anoxia. Hypoxia usually activates anaerobic glycolysis, which may be temporary when the animals are able to improve their oxygen extraction capacity. Switching over to aerobic metabolism allows

  6. Wnt3a regulates proliferation and migration of HUVEC via canonical and non-canonical Wnt signaling pathways

    International Nuclear Information System (INIS)

    Samarzija, Ivana; Sini, Patrizia; Schlange, Thomas; MacDonald, Gwen; Hynes, Nancy E.

    2009-01-01

    Untangling the signaling pathways involved in endothelial cell biology is of central interest for the development of antiangiogenesis based therapies. Here we report that Wnt3a induces the proliferation and migration of HUVECs, but does not affect their survival. Wnt3a-induced proliferation was VEGFR signaling independent, but reduced upon CamKII inhibition. In a search for the downstream mediators of Wnt3a's effects on HUVEC biology, we found that Wnt3a treatment leads to phosphorylation of DVL3 and stabilization of β-catenin. Moreover, under the same conditions we observed an upregulation in c-MYC, TIE-2 and GJA1 mRNA transcripts. Although treatment of HUVECs with Wnt5a induced DVL3 phosphorylation, we did not observe any of the other effects seen upon Wnt3a stimulation. Taken together, our data indicate that Wnt3a induces canonical and non-canonical Wnt signaling in HUVECs, and stimulates their proliferation and migration.

  7. Ibuprofen Blunts Ventilatory Acclimatization to Sustained Hypoxia in Humans.

    Directory of Open Access Journals (Sweden)

    Kemal Erdem Basaran

    Full Text Available Ventilatory acclimatization to hypoxia is a time-dependent increase in ventilation and the hypoxic ventilatory response (HVR that involves neural plasticity in both carotid body chemoreceptors and brainstem respiratory centers. The mechanisms of such plasticity are not completely understood but recent animal studies show it can be blocked by administering ibuprofen, a nonsteroidal anti-inflammatory drug, during chronic hypoxia. We tested the hypothesis that ibuprofen would also block the increase in HVR with chronic hypoxia in humans in 15 healthy men and women using a double-blind, placebo controlled, cross-over trial. The isocapnic HVR was measured with standard methods in subjects treated with ibuprofen (400 mg every 8 hrs or placebo for 48 hours at sea level and 48 hours at high altitude (3,800 m. Subjects returned to sea level for at least 30 days prior to repeating the protocol with the opposite treatment. Ibuprofen significantly decreased the HVR after acclimatization to high altitude compared to placebo but it did not affect ventilation or arterial O2 saturation breathing ambient air at high altitude. Hence, compensatory responses prevent hypoventilation with decreased isocapnic ventilatory O2-sensitivity from ibuprofen at this altitude. The effect of ibuprofen to decrease the HVR in humans provides the first experimental evidence that a signaling mechanism described for ventilatory acclimatization to hypoxia in animal models also occurs in people. This establishes a foundation for the future experiments to test the potential role of different mechanisms for neural plasticity and ventilatory acclimatization in humans with chronic hypoxemia from lung disease.

  8. A Wnt oscillator model for somitogenesis

    DEFF Research Database (Denmark)

    Jensen, Peter B; Pedersen, Lykke; Krishna, Sandeep

    2010-01-01

    We propose a model for the segmentation clock in vertebrate somitogenesis, based on the Wnt signaling pathway. The core of the model is a negative feedback loop centered around the Axin2 protein. Axin2 is activated by beta-catenin, which in turn is degraded by a complex of GSK3beta and Axin2....... The model produces oscillatory states of the involved constituents with typical time periods of a few hours (ultradian oscillations). The oscillations are robust to changes in parameter values and are often spiky, where low concentration values of beta-catenin are interrupted by sharp peaks. Necessary...

  9. Can we safely target the WNT pathway?

    Science.gov (United States)

    Kahn, Michael

    2015-01-01

    WNT–β-catenin signalling is involved in a multitude of developmental processes and the maintenance of adult tissue homeostasis by regulating cell proliferation, differentiation, migration, genetic stability and apoptosis, as well as by maintaining adult stem cells in a pluripotent state. Not surprisingly, aberrant regulation of this pathway is therefore associated with a variety of diseases, including cancer, fibrosis and neurodegeneration. Despite this knowledge, therapeutic agents specifically targeting the WNT pathway have only recently entered clinical trials and none has yet been approved. This Review examines the problems and potential solutions to this vexing situation and attempts to bring them into perspective. PMID:24981364

  10. A Wnt Oscillator Model for Somitogenesis

    OpenAIRE

    Jensen, Peter B.; Pedersen, Lykke; Krishna, Sandeep; Jensen, Mogens H.

    2010-01-01

    We propose a model for the segmentation clock in vertebrate somitogenesis, based on the Wnt signaling pathway. The core of the model is a negative feedback loop centered around the Axin2 protein. Axin2 is activated by β-catenin, which in turn is degraded by a complex of GSK3β and Axin2. The model produces oscillatory states of the involved constituents with typical time periods of a few hours (ultradian oscillations). The oscillations are robust to changes in parameter values and are often sp...

  11. Cirmtuzumab inhibits Wnt5a-induced Rac1 activation in chronic lymphocytic leukemia treated with ibrutinib.

    Science.gov (United States)

    Yu, J; Chen, L; Cui, B; Wu, Christina; Choi, M Y; Chen, Y; Zhang, L; Rassenti, L Z; Widhopf Ii, G F; Kipps, T J

    2017-06-01

    Signaling via the B cell receptor (BCR) plays an important role in the pathogenesis and progression of chronic lymphocytic leukemia (CLL). This is underscored by the clinical effectiveness of ibrutinib, an inhibitor of Bruton's tyrosine kinase (BTK) that can block BCR-signaling. However, ibrutinib cannot induce complete responses (CR) or durable remissions without continued therapy, suggesting alternative pathways also contribute to CLL growth/survival that are independent of BCR-signaling. ROR1 is a receptor for Wnt5a, which can promote activation of Rac1 to enhance CLL-cell proliferation and survival. In this study, we found that CLL cells of patients treated with ibrutinib had activated Rac1. Moreover, Wnt5a could induce Rac1 activation and enhance proliferation of CLL cells treated with ibrutinib at concentrations that were effective in completely inhibiting BTK and BCR-signaling. Wnt5a-induced Rac1 activation could be blocked by cirmtuzumab (UC-961), an anti-ROR1 mAb. We found that treatment with cirmtuzumab and ibrutinib was significantly more effective than treatment with either agent alone in clearing leukemia cells in vivo. This study indicates that cirmtuzumab may enhance the activity of ibrutinib in the treatment of patients with CLL or other ROR1 + B-cell malignancies.

  12. Integrin Activation Contributes to Lower Cisplatin Sensitivity in MV3 Melanoma Cells by Inducing the Wnt Signalling Pathway

    Directory of Open Access Journals (Sweden)

    Maria B. R. Piva

    2017-09-01

    Full Text Available Background: integrins have been associated with the development of chemotherapy resistant tumour cells, mostly those of hematopoietic origin, by mediating the binding to the extracellular matrix. The relevance for solid tumour cells and the underlying mechanisms remain elusive. Methods: using MTT assays, we detected the loss in cisplatin sensitivity of human MV3 melanoma cells upon integrin activation. Underlying cellular pathways were evaluated by flow cytometry. A crosstalk between integrin activation and the canonical wnt signalling pathway was tested by measuring β-catenin activity. Results: MV3 cells display a higher resistance against cisplatin cytotoxicity when cellular integrins were activated by manganese or collagen. Proteome profiler array showed a deregulation of the integrin expression pattern by cisplatin. Integrin activation by manganese induces the phosphorylation of PI3K/AKT. The inhibition of PI3K using BEZ235 strongly increases cell sensitivity to cisplatin, blocking manganese and collagen effects. PI3K/AKT activates wnt signalling by blocking Gsk3-β, which was confirmed by β-catenin up-regulation and nuclear localization. Integrins did not affect E-cadherin expression levels, thus endothelial to mesenchymal transition (EMT can be excluded. Conclusion: This is the first report on an integrin/wnt signalling activation axis addressing the consequences for chemotherapy sensitiveness of melanoma cells, which thus offers novel therapeutic targets for approaches to interfere with chemoresistance.

  13. Metastatic tumor antigen 3 is a direct corepressor of the Wnt4 pathway

    OpenAIRE

    Zhang, Hao; Singh, Rajesh R.; Talukder, Amjad H.; Kumar, Rakesh

    2006-01-01

    Here we show that expression of MTA3 inhibits ductal branching in virgin and pregnant murine transgenic mammary glands. MTA3 also suppresses the Wnt4 pathway and, thus, these findings parallel phenotypic changes in Wnt4-null mice. MTA3 represses Wnt4 transcription and Wnt4 secretion, inhibiting Wnt-target genes in mammary epithelial cells. Accordingly, knockdown of endogenous MTA3 stimulates Wnt4 expression and Wnt cellular targets. The MTA3–NuRD (nucleosome remodeling and deacetylase) comple...

  14. Roles of circulating WNT-signaling proteins and WNT-inhibitors in human adiposity, insulin resistance, insulin secretion, and inflammation.

    Science.gov (United States)

    Almario, R U; Karakas, S E

    2015-02-01

    Wingless-type MMTV integration site family member (WNT) signaling and WNT-inhibitors have been implicated in regulation of adipogenesis, insulin resistance, pancreatic function, and inflammation. Our goal was to determine serum proteins involved in WNT signaling (WNT5 and WISP2) and WNT inhibition (SFRP4 and SFRP5) as they relate to obesity, serum adipokines, insulin resistance, insulin secretion, and inflammation in humans. Study population comprised 57 insulin resistant women with polycystic ovary syndrome (PCOS) and 27 reference women. In a cross-sectional study, blood samples were obtained at fasting, during oral, and frequently sampled intravenous glucose tolerance tests. Serum WNT5, WISP2, and SFRP4 concentrations did not differ between PCOS vs. reference women. Serum WNT5 correlated inversely with weight both in PCOS and reference women, and correlated directly with insulin response during oral glucose tolerance test in PCOS women. Serum WISP2 correlated directly with fatty acid binding protein 4. Serum SFRP5 did not differ between obese (n=32) vs. nonobese (n=25) PCOS women, but reference women had lower SFRP5 (pPCOS groups). Serum SFRP5 correlated inversely with IL-1β, TNF-α, cholesterol, and apoprotein B. These findings demonstrated that WNT5 correlated inversely with adiposity and directly with insulin response, and the WNT-inhibitor SFRP5 may be anti-inflammatory. Better understanding of the role of WNT signaling in obesity, insulin resistance, insulin secretion, lipoprotein metabolism, and inflammation is important for prevention and treatment of metabolic syndrome, diabetes and cardiovascular disease. © Georg Thieme Verlag KG Stuttgart · New York.

  15. Wnt-dependent osteogenic commitment of bone marrow stromal cells using a novel GSK3β inhibitor

    Directory of Open Access Journals (Sweden)

    David A. Cook

    2014-03-01

    Using human BMSCs grown in adipogenic medium, we confirmed that AR28-mediated Wnt signalling caused a significant (p < 0.05 dose-dependent reduction of adipogenic markers. In osteogenic media, including dexamethasone, AR28 caused significant (p < 0.05 decreases in alkaline phosphatase (ALP activity compared to vehicle controls, indicative of a reduced osteogenic response. However, when excluding dexamethasone from the osteogenic media, increases in both ALP and mineralisation were identified following AR28 treatment, which was blocked by mitomycin C. Pre-treatment of BMSCs with AR28 for 7 days before osteogenic induction also increased ALP activity and mineralisation. Furthermore, BMP2-induced osteogenic differentiation was strongly enhanced by AR28 addition within 3 days, but without concomitant changes in cell number, therefore revealing BMP-dependent and independent mechanisms for Wnt-induced osteogenesis.

  16. Plasma volume in acute hypoxia

    DEFF Research Database (Denmark)

    Poulsen, T D; Klausen, T; Richalet, J P

    1998-01-01

    Exposure to acute hypoxia is associated with changes in body fluid homeostasis and plasma volume (PV). This study compared a dye dilution technique using Evans' blue (PV[Evans']) with a carbon monoxide (CO) rebreathing method (PV[CO]) for measurements of PV in ten normal subjects at sea level...

  17. Preeclampsia, Hypoxia, Thrombosis, and Inflammation

    Directory of Open Access Journals (Sweden)

    Amir A. Shamshirsaz

    2012-01-01

    Full Text Available Reductions in uteroplacental flow initiate a cascade of molecular effects leading to hypoxia, thrombosis, inflammation, and endothelial cell dysfunction resulting in untoward pregnancy outcomes. In this review, we detail these effects and their relationship to preeclampsia (PE and intrauterine growth restriction (IUGR.

  18. Hepcidin: A Critical Regulator Of Iron Metabolism During Hypoxia

    Science.gov (United States)

    2011-01-01

    inducible factor (HIF)/hypoxia response element ( HRE ) system, as well as recent evidence indicating that localized adipose hypoxia due to obesity may...mechanisms by which hypoxia affects hepcidin expression, to include a review of the hypoxia inducible factor (HIF)/hypoxia response element ( HRE ) system, as...a battery of genes are induced by the hypoxia inducible factor (HIF)/hypoxia response element ( HRE ) system. The HIF system senses O2 levels through

  19. Wnt inhibition promotes vascular specification of embryonic cardiac progenitors.

    Science.gov (United States)

    Reichman, David E; Park, Laura; Man, Limor; Redmond, David; Chao, Kenny; Harvey, Richard P; Taketo, Makoto M; Rosenwaks, Zev; James, Daylon

    2018-01-08

    Several studies have demonstrated a multiphasic role for Wnt signaling during embryonic cardiogenesis and developed protocols that enrich for cardiac derivatives during in vitro differentiation of human pluripotent stem cells (hPSCs). However, few studies have investigated the role of Wnt signaling in the specification of cardiac progenitor cells (CPCs) toward downstream fates. Using transgenic mice and hPSCs, we tracked endothelial cells (ECs) that originated from CPCs expressing NKX2.5. Analysis of EC-fated CPCs at discrete phenotypic milestones during hPSC differentiation identified reduced Wnt activity as a hallmark of EC specification, and the enforced activation or inhibition of Wnt reduced or increased, respectively, the degree of vascular commitment within the CPC population during both hPSC differentiation and mouse embryogenesis. Wnt5a, which has been shown to exert an inhibitory influence on Wnt signaling during cardiac development, was dynamically expressed during vascular commitment of hPSC-derived CPCs, and ectopic Wnt5a promoted vascular specification of hPSC-derived and mouse embryonic CPCs. © 2018. Published by The Company of Biologists Ltd.

  20. Role of WNT signaling in epididymal sperm maturation.

    Science.gov (United States)

    Cheng, Jin-Mei; Tang, Ji-Xin; Li, Jian; Wang, Yu-Qian; Wang, Xiu-Xia; Zhang, Yan; Chen, Su-Ren; Liu, Yi-Xun

    2018-02-01

    Spermatozoa maturation, a process required for spermatozoa to acquire progressive motility and the ability to fertilize ova, primarily occurs in the caput and corpus of the epididymis. Despite considerable efforts, the factor(s) promoting epididymal sperm maturation remains unclear. Recently, WNT signaling has been implicated in epididymal sperm maturation. To further investigate WNT signaling function in epididymal sperm maturation, we generated Wntless conditional knockout mice (Wls cKO), Wls flox/flox ; Lcn5-Cre. In these mice, WNTLESS (WLS), a conserved membrane protein required for all WNT protein secretion, was specifically disrupted in the principal cells of the caput epididymidis. Immunoblot analysis showed that WLS was significantly reduced in the caput epididymidis of Wls cKO mice. In the caput epididymidis of Wls cKO mice, WNT 10A and WNT 2b, which are typically secreted by the principal cells of the caput epididymis, were not secreted. Interestingly, sperm motility analysis showed that the WLS deficiency in the caput epididymidis had no effect on sperm motility. Moreover, fertility tests showed that Wls cKO male mice had normal fertility. These results indicate that the disruption of WLS in principal cells of the caput epididymidis inhibits WNT protein secretion but has no effect on sperm motility and male fertility, suggesting that WNT signaling in the caput epididymidis may be dispensable for epididymal sperm maturation in mice.

  1. Role of TRIM33 in Wnt signaling during mesendoderm differentiation.

    Science.gov (United States)

    Xia, Xiaojie; Zuo, Feifei; Luo, Maoguo; Sun, Ye; Bai, Jianbo; Xi, Qiaoran

    2017-10-01

    Tripartite motif 33 (TRIM33), a member of the transcription intermediate factor 1 (TIF1) family of transcription cofactors, mediates transforming growth factor-beta (TGF-β) signaling through its PHD-Bromo cassette in mesendoderm differentiation during early mouse embryonic development. However, the role of the TRIM33 RING domain in embryonic differentiation is less clear. Here, we report that TRIM33 mediates Wnt signaling by directly regulating the expression of a specific subset of Wnt target genes, and this action is independent of its RING domain. We show that TRIM33 interacts with β-catenin, a central player in Wnt signaling in mouse embryonic stem cells (mESCs). In contrast to previous reports in cancer cell lines, the RING domain does not appear to function as the E3 ligase for β-catenin, since neither knockout nor overexpression of TRIM33 had an effect on β-catenin protein levels in mESCs. Furthermore, we show that although TRIM33 seems to be dispensable for Wnt signaling through a reporter assay, loss of TRIM33 significantly impairs the expression of a subset of Wnt target genes, including Mixl1, in a Wnt signaling-dependent manner. Together, our results indicate that TRIM33 regulates Wnt signaling independent of the E3 ligase activity of its RING domain for β-catenin in mESCs.

  2. Detection block

    International Nuclear Information System (INIS)

    Bezak, A.

    1987-01-01

    A diagram is given of a detection block used for monitoring burnup of nuclear reactor fuel. A shielding block is an important part of the detection block. It stabilizes the fuel assembly in the fixing hole in front of a collimator where a suitable gamma beam is defined for gamma spectrometry determination of fuel burnup. The detector case and a neutron source case are placed on opposite sides of the fixing hole. For neutron measurement for which the water in the tank is used as a moderator, the neutron detector-fuel assembly configuration is selected such that neutrons from spontaneous fission and neutrons induced with the neutron source can both be measured. The patented design of the detection block permits longitudinal travel and rotation of the fuel assembly to any position, and thus more reliable determination of nuclear fuel burnup. (E.S.). 1 fig

  3. Niclosamide suppresses hepatoma cell proliferation via the Wnt pathway

    Directory of Open Access Journals (Sweden)

    Tomizawa M

    2013-11-01

    Full Text Available Minoru Tomizawa,1 Fuminobu Shinozaki,2 Yasufumi Motoyoshi,3 Takao Sugiyama,4 Shigenori Yamamoto,5 Makoto Sueishi,4 Takanobu Yoshida6 1Department of Gastroenterology, 2Department of Radiology, 3Department of Neurology, 4Department of Rheumatology, 5Department of Pediatrics, 6Department of Internal Medicine, National Hospital Organization Shimoshizu Hospital, Yotsukaido City, Chiba, Japan Background: The Wnt pathway plays an important role in hepatocarcinogenesis. We analyzed the association of the Wnt pathway with the proliferation of hepatoma cells using Wnt3a and niclosamide, a drug used to treat tapeworm infection. Methods: We performed an MTS assay to determine whether Wnt3a stimulated proliferation of Huh-6 and Hep3B human hepatoma cell lines after 72 hours of incubation with Wnt3a in serum-free medium. The cells were subjected to hematoxylin and eosin staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL after 48 hours of incubation. RNA was isolated 48 hours after addition of Wnt3a or niclosamide, and cyclin D1 expression levels were analyzed by real-time quantitative polymerase chain reaction. The promoter activity of T-cell factor was analyzed by luciferase assay 48 hours after transfection of TOPflash. Western blot analysis was performed with antibodies against β-catenin, dishevelled 2, and cyclin D1. Results: Cell proliferation increased with Wnt3a. Niclosamide suppressed proliferation with or without Wnt3a. Hematoxylin and eosin and TUNEL staining suggested that apoptosis occurred in cells with niclosamide. Cyclin D1 was upregulated in the presence of Wnt3a and downregulated with addition of niclosamide. The promoter activity of T-cell factor increased with Wnt3a, whereas T-cell factor promoter activity decreased with niclosamide. Western blot analysis showed that Wnt3a upregulated β-catenin, dishevelled 2, and cyclin D1, while niclosamide downregulated them. Conclusion: Niclosamide is a potential

  4. Wnt/β-Catenin Signaling during Cardiac Development and Repair

    Directory of Open Access Journals (Sweden)

    Jan W. Buikema

    2014-05-01

    Full Text Available Active Wnt/β-catenin signaling is essential for proper cardiac specification, progenitor expansion and myocardial growth. During development, the mass of the embryonic heart increases multiple times to achieve the dimensions of adult ventricular chambers. Cell division in the embryonic heart is fairly present, whereas cell turnover in the adult myocardium is extremely low. Understanding of embryonic cardiomyocyte cell-replication, therefore, could improve strategies for cardiac regenerative therapeutics. Here, we review which role Wnt signaling plays in cardiac development and highlight a selection of attempts that have been made to modulate Wnt signaling after cardiac ischemic injury to improve cardiac function and reduce infarct size.

  5. Wnt Signaling Cascades and the Roles of Syndecan Proteoglycans

    DEFF Research Database (Denmark)

    Pataki, Csilla A; Couchman, John R; Brábek, Jan

    2015-01-01

    /planar cell polarity and Wnt/calcium signaling. Syndecans are type I transmembrane proteoglycans with a long evolutionary history, being expressed in all Bilateria and in almost all cell types. Both Wnt pathways have been extensively studied over the past 30 years and shown to have roles during development...... and in a multitude of diseases. Although the first evidence for interactions between syndecans and Wnts dates back to 1997, the number of studies connecting these pathways is low, and many open questions remained unanswered. In this review, syndecan's involvement in Wnt signaling pathways as well as some...

  6. Wnt3a Promotes the Vasculogenic Mimicry Formation of Colon Cancer via Wnt/β-Catenin Signaling.

    Science.gov (United States)

    Qi, Lisha; Song, Wangzhao; Liu, Zhiyong; Zhao, Xiulan; Cao, Wenfeng; Sun, Baocun

    2015-08-10

    Our previous study provided evidence that non-canonical Wnt signaling is involved in regulating vasculogenic mimicry (VM) formation. However, the functions of canonical Wnt signaling in VM formation have not yet been explored. In this study, we found the presence of VM was related to colon cancer histological differentiation (p colon cancer samples showed increased Wnt3a expression (p colon cancer cells promoted the capacity to form tube-like structures in the three-dimensional (3-D) culture together with increased expression of endothelial phenotype-associated proteins such as VEGFR2 and VE-cadherin. The mouse xenograft model showed that Wnt3a-overexpressing cells grew into larger tumor masses and formed more VM than the control cells. In addition, the Wnt/β-catenin signaling antagonist Dickkopf-1(Dkk1) can reverse the capacity to form tube-like structures and can decrease the expressions of VEGFR2 and VE-cadherin in Wnt3a-overexpressing cells. Taken together, our results suggest that Wnt/β-catenin signaling is involved in VM formation in colon cancer and might contribute to the development of more accurate treatment modalities aimed at VM.

  7. Identification of Noncanonical Wnt Receptors Required for Wnt-3a-Induced Early Differentiation of Human Neural Stem Cells.

    Science.gov (United States)

    Bengoa-Vergniory, Nora; Gorroño-Etxebarria, Irantzu; López-Sánchez, Inmaculada; Marra, Michele; Di Chiaro, Pierluigi; Kypta, Robert

    2017-10-01

    Wnt proteins preferentially activate either β-catenin-dependent or β-catenin-independent signals, but the activity of a particular Wnt also depends on cellular context and receptor availability. We previously reported that Wnt-3a induces neural differentiation of human embryonic stem cell-derived neural stem cells (NSCs) in a β-catenin-independent manner by activating a signal involving JNK and the AP-1 family member ATF-2. Here, we report the results of a gene silencing approach to identify the Wnt receptors that mediate this response to Wnt-3a. Silencing of ROR2 increased neuronal differentiation, as measured by expression of the genes DCX, NEUROD1, and NGN1, suggesting ROR2 signals normally prevent differentiation. Silencing of the other Wnt receptors singly did not affect Wnt-3a-induced neuronal differentiation. However, pairwise silencing of ROR1 and FZD4 or FZD5 and of LRP6 and FZD4 or FZD5 inhibited neuronal differentiation, as detected by reductions in the expression of neuronal genes and immunocytochemical detection of DCX, NEUROD1 and DCX. Ectopic expression of these receptors in HEK 293 cells increased ATF2-dependent transcription. In addition, ROR1 coimmunoprecipitated with FZD4 and LRP6 in transfected HEK 293 cells and colocalized with FZD4 and with LRP6 at the cell surface of transfected L cells. Wnt-3a did not appear to affect these interactions but did alter the interactions between LRP6 and FZD4/5. Together, these observations highlight roles for ROR1, LRP6, FZD4, and FZD5 in neural stem cell differentiation and provide support for a model in which dynamic interactions among these receptors mediate Wnt-3a activation of ATF2 signaling.

  8. Ageing and cardiorespiratory response to hypoxia.

    Science.gov (United States)

    Lhuissier, François J; Canouï-Poitrine, Florence; Richalet, Jean-Paul

    2012-11-01

    The risk of severe altitude-induced diseases is related to ventilatory and cardiac responses to hypoxia and is dependent on sex, age and exercise training status. However, it remains unclear how ageing modifies these physiological adaptations to hypoxia. We assessed the physiological responses to hypoxia with ageing through a cross-sectional 20 year study including 4675 subjects (2789 men, 1886 women; 14-85 years old) and a longitudinal study including 30 subjects explored at a mean 10.4 year interval. The influence of sex, training status and menopause was evaluated. The hypoxia-induced desaturation and the ventilatory and cardiac responses to hypoxia at rest and exercise were measured. In men, ventilatory response to hypoxia increased (P ageing. Cardiac response to hypoxia was blunted with ageing in both sexes (P ageing. These adaptive responses were less pronounced or absent in post-menopausal women (P ageing in men while cardiac response is blunted with ageing in both sexes. Training aggravates desaturation at exercise in hypoxia, improves the ventilatory response and limits the ageing-induced blunting of cardiac response to hypoxia. Training limits the negative effects of menopause in cardiorespiratory adaptations to hypoxia.

  9. Exercise Improves Mood State in Normobaric Hypoxia.

    Science.gov (United States)

    Seo, Yongsuk; Fennell, Curtis; Burns, Keith; Pollock, Brandon S; Gunstad, John; McDaniel, John; Glickman, Ellen

    2015-11-01

    The purpose of this study was to quantify the efficacy of using exercise to alleviate the impairments in mood state associated with hypoxic exposure. Nineteen young, healthy men completed Automated Neuropsychological Assessment Metrics-4(th) Edition (ANAM4) versions of the mood state test before hypoxia exposure, after 60 min of hypoxia exposure (12.5% O(2)), and during and after two intensities of cycling exercise (40% and 60% adjusted Vo(2max)) under the same hypoxic conditions. Peripheral oxygen saturation (Spo(2)) and regional cerebral oxygen saturation (rSo(2)) were continuously monitored. At rest in hypoxia, Total Mood Disturbance (TMD) was significantly increased compared to baseline in both the 40% and 60% groups. TMD was significantly decreased during exercise compared to rest in hypoxia. TMD was also significantly decreased during recovery compared to rest in hypoxia. Spo(2) significantly decreased at 60 min rest in hypoxia, during exercise, and recovery compared to baseline. Regional cerebral oxygen saturation was also reduced at 60 min rest in hypoxia, during exercise, and recovery compared to baseline. The current study demonstrated that exercise at 40% and 60% of adjusted Vo(2max) attenuated the adverse effects of hypoxia on mood. These findings may have significant applied value, as negative mood states are known to impair performance in hypoxia. Further studies are needed to replicate the current finding and to clarify the possible mechanisms associated with the potential benefits of exercise on mood state in normobaric hypoxia.

  10. Approximate Simulation of Acute Hypobaric Hypoxia with Normobaric Hypoxia

    Science.gov (United States)

    Conkin, J.; Wessel, J. H., III

    2011-01-01

    INTRODUCTION. Some manufacturers of reduced oxygen (O2) breathing devices claim a comparable hypobaric hypoxia (HH) training experience by providing F(sub I) O2 pO2) of the target altitude. METHODS. Literature from investigators and manufacturers indicate that these devices may not properly account for the 47 mmHg of water vapor partial pressure that reduces the inspired partial pressure of O2 (P(sub I) O2). Nor do they account for the complex reality of alveolar gas composition as defined by the Alveolar Gas Equation. In essence, by providing iso-pO2 conditions for normobaric hypoxia (NH) as for HH exposures the devices ignore P(sub A)O2 and P(sub A)CO2 as more direct agents to induce signs and symptoms of hypoxia during acute training exposures. RESULTS. There is not a sufficient integrated physiological understanding of the determinants of P(sub A)O2 and P(sub A)CO2 under acute NH and HH given the same hypoxic pO2 to claim a device that provides isohypoxia. Isohypoxia is defined as the same distribution of hypoxia signs and symptoms under any circumstances of equivalent hypoxic dose, and hypoxic pO2 is an incomplete hypoxic dose. Some devices that claim an equivalent HH experience under NH conditions significantly overestimate the HH condition, especially when simulating altitudes above 10,000 feet (3,048 m). CONCLUSIONS. At best, the claim should be that the devices provide an approximate HH experience since they only duplicate the ambient pO2 at sea level as at altitude (iso-pO2 machines). An approach to reduce the overestimation is to at least provide machines that create the same P(sub I)O2 (iso-P(sub I)O2 machines) conditions at sea level as at the target altitude, a simple software upgrade.

  11. Delayed innocent bystander cell death following hypoxia in Caenorhabditis elegans.

    Science.gov (United States)

    Sun, C-L; Kim, E; Crowder, C M

    2014-04-01

    After hypoxia, cells may die immediately or have a protracted course, living or dying depending on an incompletely understood set of cell autonomous and nonautonomous factors. In stroke, for example, some neurons are thought to die from direct hypoxic injury by cell autonomous primary mechanisms, whereas other so called innocent bystander neurons die from factors released from the primarily injured cells. A major limitation in identifying these factors is the inability of current in vivo models to selectively target a set of cells for hypoxic injury so that the primarily injured cells and the innocent bystanders are clearly delineated. In order to develop such a model, we generated transgenic Caenorhabditis elegans strains where 2-3% of somatic cells were made selectively sensitive to hypoxia. This was accomplished by cell type-specific wild-type rescue in either pharyngeal myocytes or GABAergic neurons of a hypoxia resistance-producing translation factor mutation. Surprisingly, hypoxic targeting of these relatively small subsets of non-essential cells produced widespread innocent bystander cell injury, behavioral dysfunction and eventual organismal death. The hypoxic injury phenotypes of the myocyte or neuron sensitized strains were virtually identical. Using this model, we show that the C. elegans insulin receptor/FOXO transcription factor pathway improves survival when activated only after hypoxic injury and blocks innocent bystander death.

  12. Hypoxia and metastasis in an orthotopic cervix cancer xenograft model

    International Nuclear Information System (INIS)

    Chaudary, Naz; Mujcic, Hilda; Wouters, Bradly G.; Hill, Richard P.

    2013-01-01

    Background: Hypoxia can promote tumor metastasis by mechanisms that are believed to result from changes in gene expression. The current study examined the role of putative metastatic genes regulated by cyclic hypoxia in relation to metastasis formation in orthotopic models of cervix cancer. Methods: Orthotopic tumors derived from ME180 human cervix cancer cells or from early generation human cervix cancer xenografts were exposed to cyclic hypoxic conditions during growth in vivo and tumor growth and lymphnode metastases were monitored. Expression of the chemokine receptor CXCR4 and various genes in the Hedgehog (Hh) pathway were inhibited using genetic (inducible shRNA vs CXCR4) small molecule (AMD3100) or antibody (5E1) treatment (CXCR4 and Hh genes, respectively) during tumor growth. Results: As reported previously, exposure of tumor bearing mice to cyclic hypoxia caused a reduction of tumor growth but a large increase in metastasis. Inhibition of CXCR4 or Hh gene activity during tumor growth further reduced primary tumor size and reduced lymphatic metastasis to levels below those seen in control mice exposed to normoxic conditions. Conclusion: Blocking CXCR4 or Hh gene expression are potential therapeutic pathways for improving cervix cancer treatment

  13. LncRNA TUG1 serves an important role in hypoxia-induced myocardial cell injury by regulating the miR-145-5p-Binp3 axis

    Science.gov (United States)

    Wu, Zhongwei; Zhao, Shengji; Li, Chunfu; Liu, Chaoquan

    2018-01-01

    The aim of the present study was to investigate the function of long non-coding RNA TUG1 in hypoxia-induced myocardial cell injury and to explore the potential molecular mechanisms. The cardiomyocyte cell line H9c2 was cultured under hypoxic and normoxic conditions. TUG1 expression under hypoxic conditions was then detected. The effects of TUG1 overexpression on viability, apoptosis, migration and invasion were assayed. In addition, the microRNA (miR)-145-5p expression was detected. Following H9c2 cell transfection with miR-145-5p mimics, the H9c2 cell viability, apoptosis, migration and invasion were also detected. Additionally, the target gene of miR-145-5p was assayed by Luciferase reporter assay. The protein expressions of Wnt-3a, Wnt5a, and β-catenin in H9c2 cells under hypoxic conditions were also determined. The results revealed that hypoxia induced injury in H9c2 cells, including inhibiting cell viability, migration and invasion, and promoting cell apoptosis. Overexpression of TUG1 aggravated hypoxia-induced injury in H9c2 cells. In addition, miR-145-5p was negatively regulated by TUG1, and TUG1 overexpression aggravated hypoxia-induced injury via the downregulation of miR-145-5p. Furthermore, B-cell lymphoma 2 interacting protein 3 (Bnip3) was a target of miR-145-5p, and overexpression of Bnip3 aggravated hypoxia-induced cell injury by activating Wnt/β-catenin signaling pathways in H9c2 cells. In conclusion, overexpression of TUG1 aggravated hypoxia-induced injury in cardiomyocytes by regulating the miR-145-5p-Binp3 axis. Activation of the Wnt/β-catenin signaling pathway may be a key mechanism to mediate the role of TUG1 in regulating hypoxia-induced myocardial injury. TUG1 may be an effective diagnostic marker and therapeutic target for myocardial ischemia. PMID:29207102

  14. Role of LncRNA TUG1 in intervertebral disc degeneration and nucleus pulposus cells via regulating Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Chen, Jiang; Jia, Yu-Song; Liu, Gen-Zhe; Sun, Qi; Zhang, Fan; Ma, Sheng; Wang, Yong-Jun

    2017-09-23

    To investigate the role of TUG1 in intervertebral disc degeneration (IDD) and human nucleus pulposus cells (NPCs) via regulating Wnt/β-catenin pathway. The study collected nucleus pulposus (NP) tissue samples from 30 patients with lumbar disc herniation (LDH) (Case group) and 18 patients with lumbar spine trauma (Control group). NPCs induced by TNF-α in vitro were divided into Blank, Vector, TUG1, TUG1-siRNA, XAV-939, TUG1 + XAV-939 groups. qRT-PCR was used to detect the expression of TUG1 and ECM-related genes, Western blot to determine the expression of Wnt/β-catenin pathway and apoptosis-related proteins, and ELISA to measure the expression of ECM-related proteins. The apoptosis was detected by TUNEL and Annexin V-FITC/PI double-staining. The proliferation and senescence were tested by CCK-8 and SA-β-gal staining respectively. TUG1 was upregulated in patients with IDD, which was positively related to Wnt and β-catenin. Besides, TUG1, Wnt1 and β-catenin were greatly increased in the NPCs after TNF-α induction. Compared with the Blank group, TUG1-siRNA and XAV-939 can appreciably down-regulate the expressions of Wnt1, β-catenin, Caspase-3, Bax, MMP3 and ADAMTS5, up-regulate the expression of Bcl-2, Aggrecan and COL2A1, inhibit the apoptosis and senescence, and promote cell proliferation; however, the TUG1 group had the completely opposite results. Silencing TUG1 may not only protect human NPCs from TNF-α-induced apoptosis and senescence, but also promote cell proliferation by blocking Wnt/β-catenin pathway, which provides a theoretical basis for the clinical treatment of IDD. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Identification of two novel activities of the Wnt signaling regulator Dickkopf 3 and characterization of its expression in the mouse retina

    Directory of Open Access Journals (Sweden)

    Yi Hyun

    2007-12-01

    Full Text Available Abstract Background The Wnt signaling pathway is a cellular communication pathway that plays critical roles in development and disease. A major class of Wnt signaling regulators is the Dickkopf (Dkk family of secreted glycoproteins. Although the biological properties of Dickkopf 1 (Dkk1 and Dickkopf 2 (Dkk2 are well characterized, little is known about the function of the related Dickkopf 3 (Dkk3 protein in vivo or in cell lines. We recently demonstrated that Dkk3 transcripts are upregulated during photoreceptor death in a mouse model of retinal degeneration. In this study, we characterized the activity of Dkk3 in Wnt signaling and cell death. Results Dkk3 was localized to Müller glia and retinal ganglion cells in developing and adult mouse retina. Western blotting confirmed that Dkk3 is secreted from Müller glia cells in culture. We demonstrated that Dkk3 potentiated Wnt signaling in Müller glia and HEK293 cells but not in COS7 cells, indicating that it is a cell-type specific regulator of Wnt signaling. This unique Dkk3 activity was blocked by co-expression of Dkk1. Additionally, Dkk3 displayed pro-survival properties by decreasing caspase activation and increasing viability in HEK293 cells exposed to staurosporine and H2O2. In contrast, Dkk3 did not protect COS7 cells from apoptosis. Conclusion These data demonstrate that Dkk3 is a positive regulator of Wnt signaling, in contrast to its family member Dkk1. Furthermore, Dkk3 protects against apoptosis by reducing caspase activity, suggesting that Dkk3 may play a cytoprotective role in the retina.

  16. Effect of Wnt3a on Keratinocytes Utilizing in Vitro and Bioinformatics Analysis

    Directory of Open Access Journals (Sweden)

    Ju-Suk Nam

    2014-03-01

    Full Text Available Wingless-type (Wnt signaling proteins participate in various cell developmental processes. A suppressive role of Wnt5a on keratinocyte growth has already been observed. However, the role of other Wnt proteins in proliferation and differentiation of keratinocytes remains unknown. Here, we investigated the effects of the Wnt ligand, Wnt3a, on proliferation and differentiation of keratinocytes. Keratinocytes from normal human skin were cultured and treated with recombinant Wnt3a alone or in combination with the inflammatory cytokine, tumor necrosis factor α (TNFα. Furthermore, using bioinformatics, we analyzed the biochemical parameters, molecular evolution, and protein–protein interaction network for the Wnt family. Application of recombinant Wnt3a showed an anti-proliferative effect on keratinocytes in a dose-dependent manner. After treatment with TNFα, Wnt3a still demonstrated an anti-proliferative effect on human keratinocytes. Exogenous treatment of Wnt3a was unable to alter mRNA expression of differentiation markers of keratinocytes, whereas an altered expression was observed in TNFα-stimulated keratinocytes. In silico phylogenetic, biochemical, and protein–protein interaction analysis showed several close relationships among the family members of the Wnt family. Moreover, a close phylogenetic and biochemical similarity was observed between Wnt3a and Wnt5a. Finally, we proposed a hypothetical mechanism to illustrate how the Wnt3a protein may inhibit the process of proliferation in keratinocytes, which would be useful for future researchers.

  17. Aging in Caenorhabditis elegans; the role of Wnt signalling

    NARCIS (Netherlands)

    Lezzerini, M.

    2015-01-01

    Aging is a universal biological process, broadly characterized by the gradual decline of a multitude of physiological functions, ultimately resulting in organismal death. Wnt signaling is a major and highly conserved developmental pathway that guides many important events during organismal

  18. MGST2 and WNT2 are candidate genes for comitant strabismus susceptibility in Japanese patients

    Directory of Open Access Journals (Sweden)

    Jingjing Zhang

    2017-10-01

    Full Text Available Background/Aim Strabismus is a common condition with misalignment between two eyes that may lead to decrease of visual acuity, lack of binocularity, and diplopia. It is caused by heterogeneous environmental and genetic risk factors. Our previous research has identified new chromosomal susceptibility loci in 4q28.3 and 7q31.2 regions for comitant strabismus in Japanese families. We conducted a verification study by linkage analysis to narrow the chromosomal loci down to a single gene. Methods From Japanese and U.S. databases, 24 rsSNPs and 233 rsSNPs were chosen from the 4q28.3 and 7q31.2 region, respectively, and were typed in 108 affected subjects and 96 unaffected subjects of 58 families with primary and non-syndromic comitant strabismus. Three major analytical methods were used: transmission disequilibrium test (TDT, TDT allowing for errors (TDTae, and linkage analysis under dominant and recessive inheritance. Results The SNPs with significant P values in TDT and TDTae were located solely at the gene, microsomal glutathione S-transferase 2 (MGST2, on chromosome 4q28.3 locus. In contrast, significant SNPs were dispersed in a few genes, containing wingless-type MMTV integration site family member 2 (WNT2, on chromosome 7q31.2 locus. The distribution of significant SNPs on the 7q31.2 locus showed that only the ST7 to WNT2 region in the same big haplotype block contained significant SNPs for all three methods of linkage analysis. Conclusions This study suggests that MGST2 and WNT2 are potential candidates for comitant strabismus in Japanese population.

  19. Sudden endotracheal tube block in a patient of Achalasia Cardia

    Directory of Open Access Journals (Sweden)

    Ajit Gupta

    2012-01-01

    Full Text Available Endotracheal tube block due to various mechanical causes such as mucous, blood clot, denture, and ampoules have been reported. A patient of achalasia cardia with chronic passive aspiration pneumonitis developed mucoid mass in the respiratory passage which dislodged during the surgical procedure. The episode occurred almost an hour after induction of anesthesia and the dislodged mucoid mass blocked the lumen of endotracheal tube, leading to hypoxia and impending cardiac arrest. However, the patient was salvaged by replacing the tube.

  20. Frequent epigenetic inactivation of Wnt antagonist genes in breast cancer

    Science.gov (United States)

    Suzuki, H; Toyota, M; Caraway, H; Gabrielson, E; Ohmura, T; Fujikane, T; Nishikawa, N; Sogabe, Y; Nojima, M; Sonoda, T; Mori, M; Hirata, K; Imai, K; Shinomura, Y; Baylin, S B; Tokino, T

    2008-01-01

    Although mutation of APC or CTNNB1 (β-catenin) is rare in breast cancer, activation of Wnt signalling is nonetheless thought to play an important role in breast tumorigenesis, and epigenetic silencing of Wnt antagonist genes, including the secreted frizzled-related protein (SFRP) and Dickkopf (DKK) families, has been observed in various tumours. In breast cancer, frequent methylation and silencing of SFRP1 was recently documented; however, altered expression of other Wnt antagonist genes is largely unknown. In the present study, we found frequent methylation of SFRP family genes in breast cancer cell lines (SFRP1, 7 out of 11, 64%; SFRP2, 11 out of 11, 100%; SFRP5, 10 out of 11, 91%) and primary breast tumours (SFRP1, 31 out of 78, 40%; SFRP2, 60 out of 78, 77%; SFRP5, 55 out of 78, 71%). We also observed methylation of DKK1, although less frequently, in cell lines (3 out of 11, 27%) and primary tumours (15 out of 78, 19%). Breast cancer cell lines express various Wnt ligands, and overexpression of SFRPs inhibited cancer cell growth. In addition, overexpression of a β-catenin mutant and depletion of SFRP1 using small interfering RNA synergistically upregulated transcriptional activity of T-cell factor/lymphocyte enhancer factor. Our results confirm the frequent methylation and silencing of Wnt antagonist genes in breast cancer, and suggest that their loss of function contributes to activation of Wnt signalling in breast carcinogenesis. PMID:18283316

  1. The role of hypoxia inducible factor 1 (HIF-1) in hypoxia induced apoptosis

    NARCIS (Netherlands)

    Greijer, A.E.; Wall, E. van der

    2004-01-01

    Apoptosis can be induced in response to hypoxia. The severity of hypoxia determines whether cells become apoptotic or adapt to hypoxia and survive. A hypoxic environment devoid of nutrients prevents the cell undergoing energy dependent apoptosis and cells become necrotic. Apoptosis regulatory

  2. Recombinant adeno-associated virus-delivered hypoxia-inducible stanniocalcin-1 expression effectively inhibits hypoxia-induced cell apoptosis in cardiomyocytes.

    Science.gov (United States)

    Shi, Xin; Wang, Jianzhong; Qin, Yan

    2014-12-01

    Ischemia/hypoxia-induced oxidative stress is detrimental for the survival of cardiomyocytes and cardiac function. Stanniocalcin-1 (STC-1), a glycoprotein, has been found to play an inhibitory role in the production of reactive oxygen species (ROS). Here, we speculated that the overexpression of STC-1 might alleviate oxidative damage in cardiomyocytes under conditions of hypoxia. To control the expression of STC-1 in hypoxia, we constructed a recombinant adeno-associated virus (AAV) carrying the hypoxia-responsive element (HRE) to mediate hypoxia induction. Cardiomyocytes were infected with AAV-HRE-STC-1 and cultured in normoxic or hypoxic conditions, and STC-1 overexpression was only detected in hypoxic cultured cardiomyocytes by using quantitative real-time polymerase chain reaction and Western blot analysis. Using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, AAV-HRE-STC-1 infection was shown to significantly enhance cell survival under hypoxia. Hypoxia-induced cell apoptosis was inhibited by AAV-HRE-STC-1 infection by using the Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide apoptosis assay. Moreover, the proapoptotic protein Caspase-3 and anti-apoptotic protein Bcl-2, which were dysregulated by hypoxia, were reversed by AAV-HRE-STC-1 infection. AAV-HRE-STC-1-mediated STC-1 overexpression markedly inhibited ROS production in cardiomyocytes cultured under hypoxic conditions. AAV-HRE-STC-1 infection significantly upregulated uncoupled protein 3 (UCP3), whereas silencing of UCP3 blocked the inhibitory effect of AAV-HRE-STC-1 on ROS production. In contrast, AAV-HRE-STC-1 infection had no effect on UCP2, and knockdown of UCP2 did not block the inhibitory effect of AAV-HRE-STC-1 on ROS production in the cardiomyocytes cultured under hypoxic conditions. Taken together, STC1 activates antioxidant pathway in cardiomyocytes through the induction of UCP3, implying that AAV-HRE-STC-1 has potential in the treatment of ischemic

  3. NRP1 Accelerates Odontoblast Differentiation of Dental Pulp Stem Cells Through Classical Wnt/β-Catenin Signaling.

    Science.gov (United States)

    Song, Yihua; Liu, Xiaojuan; Feng, Xingmei; Gu, Zhifeng; Gu, Yongchun; Lian, Min; Xiao, Jingwen; Cao, Peipei; Zheng, Ke; Gu, Xiaobing; Li, Dongping; He, Ping; Wang, Chenfei

    2017-10-01

    Neuropilin-1 (NRP1) is one of the members of neuropilin family. It can combine with disparate ligands involved in regulating cell proliferation, apoptosis, and differentiation. The binding of NRP1 to Sema3A stimulates osteoblast differentiation through the classical Wnt/β-catenin pathway. However, the functions of NRP1 in dental pulp stem cells (DPSCs) are not clear. The aim of our study was to investigate how NRP1 controlled odontoblast differentiation in DPSCs and clarified the underlying mechanisms. NRP1 expression was increased in time-dependent manner along with cell odontoblast differentiation. Overexpression of NRP1 upregulated dentin matrix protein-1, dentin sialophosphoprotein, alkaline phosphatase protein level, and mineralization in DPSCs, while knockdown of NRP1 induced the opposite effects. SiNRP1 similar to DKK1 availably blocked classical Wnt/β-catenin signaling and odontoblast differentiation. In summary, NRP1, as a promoter of odontoblast differentiation, regulates DPSCs via the classical Wnt/β-catenin pathway.

  4. Canonical Wnt/β-catenin signalling is essential for optic cup formation.

    Directory of Open Access Journals (Sweden)

    Anna-Carin Hägglund

    Full Text Available A multitude of signalling pathways are involved in the process of forming an eye. Here we demonstrate that β-catenin is essential for eye development as inactivation of β-catenin prior to cellular specification in the optic vesicle caused anophthalmia in mice. By achieving this early and tissue-specific β-catenin inactivation we find that retinal pigment epithelium (RPE commitment was blocked and eye development was arrested prior to optic cup formation due to a loss of canonical Wnt signalling in the dorsal optic vesicle. Thus, these results show that Wnt/β-catenin signalling is required earlier and play a more central role in eye development than previous studies have indicated. In our genetic model system a few RPE cells could escape β-catenin inactivation leading to the formation of a small optic rudiment. The optic rudiment contained several neural retinal cell classes surrounded by an RPE. Unlike the RPE cells, the neural retinal cells could be β-catenin-negative revealing that differentiation of the neural retinal cell classes is β-catenin-independent. Moreover, although dorsoventral patterning is initiated in the mutant optic vesicle, the neural retinal cells in the optic rudiment displayed almost exclusively ventral identity. Thus, β-catenin is required for optic cup formation, commitment to RPE cells and maintenance of dorsal identity of the retina.

  5. Apc bridges Wnt/{beta}-catenin and BMP signaling during osteoblast differentiation of KS483 cells

    Energy Technology Data Exchange (ETDEWEB)

    Miclea, Razvan L., E-mail: R.L.Miclea@lumc.nl [Department of Pediatrics, Leiden University Medical Centre (LUMC), Leiden (Netherlands); Horst, Geertje van der, E-mail: G.van_der_Horst@lumc.nl [Department of Urology, LUMC, Leiden (Netherlands); Robanus-Maandag, Els C., E-mail: E.C.Robanus@lumc.nl [Department of Human Genetics, LUMC, Leiden (Netherlands); Loewik, Clemens W.G.M., E-mail: C.W.G.M.Lowik@lumc.nl [Department of Endocrinology and Metabolic Diseases, LUMC, Leiden (Netherlands); Oostdijk, Wilma, E-mail: W.Oostdijk@lumc.nl [Department of Pediatrics, Leiden University Medical Centre (LUMC), Leiden (Netherlands); Wit, Jan M., E-mail: J.M.Wit@lumc.nl [Department of Pediatrics, Leiden University Medical Centre (LUMC), Leiden (Netherlands); Karperien, Marcel, E-mail: H.B.J.Karperien@tnw.utwente.nl [MIRA Institute for Biomedical Technology and Technical Medicine, Department of Tissue Regeneration, University of Twente, Zuidhorst Room ZH 144, Drienerlolaan 5, 7522 NB Enschede (Netherlands)

    2011-06-10

    The canonical Wnt signaling pathway influences the differentiation of mesenchymal cell lineages in a quantitative and qualitative fashion depending on the dose of {beta}-catenin signaling. Adenomatous polyposis coli (Apc) is the critical intracellular regulator of {beta}-catenin turnover. To better understand the molecular mechanisms underlying the role of Apc in regulating the differentiation capacity of skeletal progenitor cells, we have knocked down Apc in the murine mesenchymal stem cell-like KS483 cells by stable expression of Apc-specific small interfering RNA. In routine culture, KSFrt-Apc{sub si} cells displayed a mesenchymal-like spindle shape morphology, exhibited markedly decreased proliferation and increased apoptosis. Apc knockdown resulted in upregulation of the Wnt/{beta}-catenin and the BMP/Smad signaling pathways, but osteogenic differentiation was completely inhibited. This effect could be rescued by adding high concentrations of BMP-7 to the differentiation medium. Furthermore, KSFrt-Apc{sub si} cells showed no potential to differentiate into chondrocytes or adipocytes. These results demonstrate that Apc is essential for the proliferation, survival and differentiation of KS483 cells. Apc knockdown blocks the osteogenic differentiation of skeletal progenitor cells, a process that can be overruled by high BMP signaling.

  6. Expression of WNT5A in Idiopathic Pulmonary Fibrosis and Its Control by TGF-β and WNT7B in Human Lung Fibroblasts.

    Science.gov (United States)

    Newman, Donna R; Sills, W Shane; Hanrahan, Katherine; Ziegler, Amanda; Tidd, Kathleen McGinnis; Cook, Elizabeth; Sannes, Philip L

    2016-02-01

    The wingless (Wnt) family of signaling ligands contributes significantly to lung development and is highly expressed in patients with usual interstitial pneumonia (UIP). We sought to define the cellular distribution of Wnt5A in the lung tissue of patients with idiopathic pulmonary fibrosis (IPF) and the signaling ligands that control its expression in human lung fibroblasts and IPF myofibroblasts. Tissue sections from 40 patients diagnosed with IPF or UIP were probed for the immunolocalization of Wnt5A. Further, isolated lung fibroblasts from normal or IPF human lungs, adenovirally transduced for the overexpression or silencing of Wnt7B or treated with TGF-β1 or its inhibitor, were analyzed for Wnt5A protein expression. Wnt5A was expressed in IPF lungs by airway and alveolar epithelium, smooth muscle cells, endothelium, and myofibroblasts of fibroblastic foci and throughout the interstitium. Forced overexpression of Wnt7B with or without TGF-β1 treatment significantly increased Wnt5A protein expression in normal human smooth muscle cells and fibroblasts but not in IPF myofibroblasts where Wnt5A was already highly expressed. The results demonstrate a wide distribution of Wnt5A expression in cells of the IPF lung and reveal that it is significantly increased by Wnt7B and TGF-β1, which, in combination, could represent key signaling pathways that modulate the pathogenesis of IPF. © 2016 The Histochemical Society.

  7. A Monoclonal Antibody against Wnt-1 Induces Apoptosis in Human Cancer Cells

    Directory of Open Access Journals (Sweden)

    Biao He

    2004-01-01

    Full Text Available Aberrant activation of the Wingless-type (Wnt/β-catenin signaling pathway is associated with a variety of human cancers. Little is known regarding the role that Wnt ligands play in human carcinogenesis. To test whether a Wnt-1 signal is a survival factor in human cancer cells and thus may serve as a potential cancer therapeutic target, we investigated the effect of inhibition of Wnt-1 signaling in a variety of human cancer cell lines, including non small cell lung cancer, breast cancer, mesothelioma, and sarcoma. Both monoclonal antibody and RNA interference (RNAi were used to inhibit Wnt-1 signaling. We found that incubation of a monoclonal anti-Wnt-1 antibody induced apoptosis and caused downstream protein changes in cancer cells overexpressing Wnt-1. In contrast, apoptosis was not detected in cells lacking or having minimal Wnt-1 expression after the antibody incubation. RNAi targeting of Wnt-1 in cancer cells overexpressing Wnt-1 demonstrated similar downstream protein changes and induction of apoptosis. The antibody also suppressed tumor growth in vivo. Our results indicate that both monoclonal anti-Wnt-1 antibody and Wnt-1 siRNA inhibit Wnt-1 signaling and can induce apoptosis in human cancer cells. These findings hold promise as a novel therapeutic strategy for cancer.

  8. Distinctive Roles of Canonical and Noncanonical Wnt Signaling in Human Embryonic Cardiomyocyte Development

    Directory of Open Access Journals (Sweden)

    Silvia Mazzotta

    2016-10-01

    Full Text Available Wnt signaling is a key regulator of vertebrate heart development; however, specific roles for human cardiomyocyte development remain uncertain. Here we use human embryonic stem cells (hESCs to analyze systematically in human cardiomyocyte development the expression of endogenous Wnt signaling components, monitor pathway activity, and dissect stage-specific requirements for canonical and noncanonical Wnt signaling mechanisms using small-molecule inhibitors. Our analysis suggests that WNT3 and WNT8A, via FZD7 and canonical signaling, regulate BRACHYURY expression and mesoderm induction; that WNT5A/5B, via ROR2 and noncanonical signaling, regulate MESP1 expression and cardiovascular development; and that later in development WNT2, WNT5A/5B, and WNT11, via FZD4 and FZD6, regulate functional cardiomyocyte differentiation via noncanonical Wnt signaling. Our findings confirm in human development previously proposed roles for canonical Wnt signaling in sequential stages of vertebrate cardiomyogenesis, and identify more precise roles for noncanonical signaling and for individual Wnt signal and Wnt receptor genes in human cardiomyocyte development.

  9. Effects of Wnt-10b on proliferation and differentiation of murine melanoma cells

    International Nuclear Information System (INIS)

    Misu, Masayasu; Ouji, Yukiteru; Kawai, Norikazu; Nishimura, Fumihiko; Nakamura-Uchiyama, Fukumi; Yoshikawa, Masahide

    2015-01-01

    In spite of the strong expression of Wnt-10b in melanomas, its role in melanoma cells has not been elucidated. In the present study, the biological effects of Wnt-10b on murine B16F10 (B16) melanoma cells were investigated using conditioned medium from Wnt-10b-producing COS cells (Wnt-CM). After 2 days of culture in the presence of Wnt-CM, proliferation of B16 melanoma cells was inhibited, whereas tyrosinase activity was increased. An in vitro wound healing assay demonstrated that migration of melanoma cells to the wound area was inhibited with the addition of Wnt-CM. Furthermore, evaluation of cellular senescence revealed prominent induction of SA-β-gal-positive senescent cells in cultures with Wnt-CM. Finally, the growth of B16 melanoma cell aggregates in collagen 3D-gel cultures was markedly suppressed in the presence of Wnt-CM. These results suggest that Wnt-10b represses tumor cell properties, such as proliferation and migration of B16 melanoma cells, driving them toward a more differentiated state along a melanocyte lineage. - Highlights: • Wnt-10b inhibited proliferation and migration of melanoma cells. • Wnt-10b induced tyrosinase activity and senescence of melanoma cells. • Wnt-10b suppressed growth of cell aggregates in collagen 3D-gel cultures. • Wnt-10b represses tumor cell properties, driving them toward a more differentiated state along a melanocyte lineage

  10. Effects of Wnt-10b on proliferation and differentiation of murine melanoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Misu, Masayasu [Department of Pathogen, Infection and Immunity, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Ouji, Yukiteru, E-mail: oujix@naramed-u.ac.jp [Department of Pathogen, Infection and Immunity, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Kawai, Norikazu [Department of Pathogen, Infection and Immunity, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Nishimura, Fumihiko [Department of Neurosurgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Nakamura-Uchiyama, Fukumi [Department of Pathogen, Infection and Immunity, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Yoshikawa, Masahide, E-mail: myoshika@naramed-u.ac.jp [Department of Pathogen, Infection and Immunity, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan)

    2015-08-07

    In spite of the strong expression of Wnt-10b in melanomas, its role in melanoma cells has not been elucidated. In the present study, the biological effects of Wnt-10b on murine B16F10 (B16) melanoma cells were investigated using conditioned medium from Wnt-10b-producing COS cells (Wnt-CM). After 2 days of culture in the presence of Wnt-CM, proliferation of B16 melanoma cells was inhibited, whereas tyrosinase activity was increased. An in vitro wound healing assay demonstrated that migration of melanoma cells to the wound area was inhibited with the addition of Wnt-CM. Furthermore, evaluation of cellular senescence revealed prominent induction of SA-β-gal-positive senescent cells in cultures with Wnt-CM. Finally, the growth of B16 melanoma cell aggregates in collagen 3D-gel cultures was markedly suppressed in the presence of Wnt-CM. These results suggest that Wnt-10b represses tumor cell properties, such as proliferation and migration of B16 melanoma cells, driving them toward a more differentiated state along a melanocyte lineage. - Highlights: • Wnt-10b inhibited proliferation and migration of melanoma cells. • Wnt-10b induced tyrosinase activity and senescence of melanoma cells. • Wnt-10b suppressed growth of cell aggregates in collagen 3D-gel cultures. • Wnt-10b represses tumor cell properties, driving them toward a more differentiated state along a melanocyte lineage.

  11. Wnt5b-associated exosomes promote cancer cell migration and proliferation.

    Science.gov (United States)

    Harada, Takeshi; Yamamoto, Hideki; Kishida, Shosei; Kishida, Michiko; Awada, Chihiro; Takao, Toshifumi; Kikuchi, Akira

    2017-01-01

    Wnt5b is a member of the same family of proteins as Wnt5a, the overexpression of which is associated with cancer aggressiveness. Wnt5b is also suggested to be involved in cancer progression, however, details remain unclarified. We analyzed the biochemical properties of purified Wnt5b and the mode of secretion of Wnt5b by cancer cells. Wnt5b was glycosylated at three asparagine residues and lipidated at one serine residue, and these post-translational modifications of Wnt5b were essential for secretion. Purified Wnt5b showed Dvl2 phosphorylation and Rac activation abilities to a similar extent as Wnt5a. In cultured-cell conditioned medium, Wnt5b was detected in supernatant or precipitation fractions that were separated by centrifugation at 100 000 g. In PANC-1 pancreatic cancer cells, 55% of secreted endogenous Wnt5b was associated with exosomes. Exosomes from wild-type PANC-1 cells, but not those from Wnt5b-knockout PANC-1 cells, activated Wnt5b signaling in CHO cells and stimulated migration and proliferation of A549 lung adenocarcinoma cells, suggesting that endogenous, Wnt5b-associated exosomes are active. The exosomes were taken up by CHO cells and immunoelectron microscopy revealed that Wnt5b is indeed associated with exosomes. In Caco-2 colon cancer cells, most Wnt5b was recovered in precipitation fractions when Wnt5b was ectopically expressed (Caco-2/Wnt5b cells). Knockdown of TSG101, an exosome marker, decreased the secretion of Wnt5b-associated exosomes from Caco-2/Wnt5b cells and inhibited Wnt5b-dependent cell proliferation. Exosomes secreted from Caco-2/Wnt5b cells stimulated migration and proliferation of A549 cells. These results suggest that Wnt5b-associated exosomes promote cancer cell migration and proliferation in a paracrine manner. © 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

  12. Toward a quantitative understanding of the Wnt/ β -catenin pathway through simulation and experiment

    KAUST Repository

    Lloyd-Lewis, Bethan; Fletcher, Alexander G.; Dale, Trevor C.; Byrne, Helen M.

    2013-01-01

    Wnt signaling regulates cell survival, proliferation, and differentiation throughout development and is aberrantly regulated in cancer. The pathway is activated when Wnt ligands bind to specific receptors on the cell surface, resulting

  13. Zinc promotes the death of hypoxic astrocytes by upregulating hypoxia-induced hypoxia-inducible factor-1alpha expression via poly(ADP-ribose) polymerase-1.

    Science.gov (United States)

    Pan, Rong; Chen, Chen; Liu, Wen-Lan; Liu, Ke-Jian

    2013-07-01

    Pathological release of excess zinc ions has been implicated in ischemic brain cell death. However, the underlying mechanisms remain to be elucidated. In stroke, ischemia-induced zinc release and hypoxia-inducible factor-1 (HIF-1) accumulation concurrently occur in the ischemic tissue. The present study tests the hypothesis that the presence of high intracellular zinc concentration is a major cause of modifications to PARP-1 and HIF-1α during hypoxia, which significantly contributes to cell death during ischemia. Primary cortical astrocytes and C8-D1A cells were exposed to different concentrations of zinc chloride. Cell death rate and protein expression of HIF-1 and Poly(ADP-ribose) polymerase (PARP)-1 were examined after 3-h hypoxic treatment. Although 3-h hypoxia or 100 μM of zinc alone did not induce noticeable cytotoxicity, their combination led to a dramatic increase in astrocytic cell death in a zinc-concentration-dependent manner. Exposure of astrocytes to hypoxia for 3 h remarkably increased the levels of intracellular zinc and HIF-1α protein, which was further augmented by added exogenous zinc. Notably, HIF-1α knockdown blocked zinc-induced astrocyte death. Moreover, knockdown of PARP-1, another important protein in the response of hypoxia, attenuated the overexpression of HIF-1α and reduced the cell death rate. Our studies show that zinc promotes hypoxic cell death through overexpression of the hypoxia response factor HIF-1α via the cell fate determine factor PARP-1 modification, which provides a novel mechanism for zinc-mediated ischemic brain injury. © 2013 John Wiley & Sons Ltd.

  14. Hypoxia Decreases Invasin-Mediated Yersinia enterocolitica Internalization into Caco-2 Cells.

    Science.gov (United States)

    Zeitouni, Nathalie E; Dersch, Petra; Naim, Hassan Y; von Köckritz-Blickwede, Maren

    2016-01-01

    Yersinia enterocolitica is a major cause of human yersiniosis, with enterocolitis being a typical manifestation. These bacteria can cross the intestinal mucosa, and invade eukaryotic cells by binding to host β1 integrins, a process mediated by the bacterial effector protein invasin. This study examines the role of hypoxia on the internalization of Y. enterocolitica into intestinal epithelial cells, since the gastrointestinal tract has been shown to be physiologically deficient in oxygen levels (hypoxic), especially in cases of infection and inflammation. We show that hypoxic pre-incubation of Caco-2 cells resulted in significantly decreased bacterial internalization compared to cells grown under normoxia. This phenotype was absent after functionally blocking host β1 integrins as well as upon infection with an invasin-deficient Y. enterocolitica strain. Furthermore, downstream phosphorylation of the focal adhesion kinase was also reduced under hypoxia after infection. In good correlation to these data, cells grown under hypoxia showed decreased protein levels of β1 integrins at the apical cell surface whereas the total protein level of the hypoxia inducible factor (HIF-1) alpha was elevated. Furthermore, treatment of cells with the HIF-1 α stabilizer dimethyloxalylglycine (DMOG) also reduced invasion and decreased β1 integrin protein levels compared to control cells, indicating a potential role for HIF-1α in this process. These results suggest that hypoxia decreases invasin-integrin-mediated internalization of Y. enterocolitica into intestinal epithelial cells by reducing cell surface localization of host β1 integrins.

  15. Hypoxia: From Placental Development to Fetal Programming.

    Science.gov (United States)

    Fajersztajn, Lais; Veras, Mariana Matera

    2017-10-16

    Hypoxia may influence normal and different pathological processes. Low oxygenation activates a variety of responses, many of them regulated by hypoxia-inducible factor 1 complex, which is mostly involved in cellular control of O 2 consumption and delivery, inhibition of growth and development, and promotion of anaerobic metabolism. Hypoxia plays a significant physiological role in fetal development; it is involved in different embryonic processes, for example, placentation, angiogenesis, and hematopoiesis. More recently, fetal hypoxia has been associated directly or indirectly with fetal programming of heart, brain, and kidney function and metabolism in adulthood. In this review, the role of hypoxia in fetal development, placentation, and fetal programming is summarized. Hypoxia is a basic mechanism involved in different pregnancy disorders and fetal health developmental complications. Although there are scientific data showing that hypoxia mediates changes in the growth trajectory of the fetus, modulates gene expression by epigenetic mechanisms, and determines the health status later in adulthood, more mechanistic studies are needed. Furthermore, if we consider that intrauterine hypoxia is not a rare event, and can be a consequence of unavoidable exposures to air pollution, nutritional deficiencies, obesity, and other very common conditions (drug addiction and stress), the health of future generations may be damaged and the incidence of some diseases will markedly increase as a consequence of disturbed fetal programming. Birth Defects Research 109:1377-1385, 2017.© 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  16. Genome-wide analysis of a Wnt1-regulated transcriptional network implicates neurodegenerative pathways.

    Science.gov (United States)

    Wexler, Eric M; Rosen, Ezra; Lu, Daning; Osborn, Gregory E; Martin, Elizabeth; Raybould, Helen; Geschwind, Daniel H

    2011-10-04

    Wnt proteins are critical to mammalian brain development and function. The canonical Wnt signaling pathway involves the stabilization and nuclear translocation of β-catenin; however, Wnt also signals through alternative, noncanonical pathways. To gain a systems-level, genome-wide view of Wnt signaling, we analyzed Wnt1-stimulated changes in gene expression by transcriptional microarray analysis in cultured human neural progenitor (hNP) cells at multiple time points over a 72-hour time course. We observed a widespread oscillatory-like pattern of changes in gene expression, involving components of both the canonical and the noncanonical Wnt signaling pathways. A higher-order, systems-level analysis that combined independent component analysis, waveform analysis, and mutual information-based network construction revealed effects on pathways related to cell death and neurodegenerative disease. Wnt effectors were tightly clustered with presenilin1 (PSEN1) and granulin (GRN), which cause dominantly inherited forms of Alzheimer's disease and frontotemporal dementia (FTD), respectively. We further explored a potential link between Wnt1 and GRN and found that Wnt1 decreased GRN expression by hNPs. Conversely, GRN knockdown increased WNT1 expression, demonstrating that Wnt and GRN reciprocally regulate each other. Finally, we provided in vivo validation of the in vitro findings by analyzing gene expression data from individuals with FTD. These unbiased and genome-wide analyses provide evidence for a connection between Wnt signaling and the transcriptional regulation of neurodegenerative disease genes.

  17. Cftr Modulates Wnt/β-Catenin Signaling and Stem Cell Proliferation in Murine Intestine

    Directory of Open Access Journals (Sweden)

    Ashlee M. Strubberg

    2018-01-01

    Conclusions: CF intestine shows increased ISC proliferation and Wnt/β-catenin signaling. Loss of Cftr increases pHi in ISCs, which stabilizes the plasma membrane association of the Wnt transducer Dvl, likely facilitating Wnt/β-catenin signaling. Absence of Cftr-dependent suppression of ISC proliferation in the CF intestine may contribute to increased risk for intestinal tumors.

  18. Targeting the Wnt/beta-catenin pathway in cancer: Update on effectors and inhibitors.

    Science.gov (United States)

    Krishnamurthy, Nithya; Kurzrock, Razelle

    2018-01-01

    The Wnt/beta-catenin pathway is a family of proteins that is implicated in many vital cellular functions such as stem cell regeneration and organogenesis. Several intra-cellular signal transduction pathways are induced by Wnt, notably the Wnt/beta-catenin dependent pathway or canonical pathway and the non-canonical or beta-catenin-independent pathway; the latter includes the Wnt/Ca2+ and Planar Cell Polarity pathway (PCP). Wnt activation occurs at the intestinal crypt floor, and is critical to optimal maintenance of stem cells. Colorectal cancers show evidence of Wnt signaling pathway activation and this is associated with loss of function of the tumor regulator APC. Wnt activation has been observed in breast, lung, and hematopoietic malignancies and contributes to tumor recurrence. The Wnt pathway cross talks with the Notch and Sonic Hedgehog pathways, which has implications for therapeutic interventions in cancers. There are significant challenges in targeting the Wnt pathway, including finding agents that are efficacious without damaging the system of normal somatic stem cell function in cellular repair and tissue homeostasis. Here, we comprehensively review the Wnt pathway and its interactions with the Notch and Sonic Hedgehog pathways. We present the state of the field in effectors and inhibitors of Wnt signaling, including updates on clinical trials in various cancers with inhibitors of Wnt, Notch, and Sonic Hedgehog. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Plasma membrane recruitment of dephosphorylated beta-catenin upon activation of the Wnt pathway

    NARCIS (Netherlands)

    Hendriksen, Jolita; Jansen, Marnix; Brown, Carolyn M.; van der Velde, Hella; van Ham, Marco; Galjart, Niels; Offerhaus, G. Johan; Fagotto, Francois; Fornerod, Maarten

    2008-01-01

    The standard model of Wnt signaling specifies that after receipt of a Wnt ligand at the membranous receptor complex, downstream mediators inhibit a cytoplasmic destruction complex, allowing beta-catenin to accumulate in the cytosol and nucleus and co-activate Wnt target genes. Unexpectedly, shortly

  20. Wnts and wing: Wnt signaling in vertebrate limb development and musculoskeletal morphogenesis.

    Science.gov (United States)

    Yang, Yingzi

    2003-11-01

    In the past twenty years, secreted signaling molecules of the Wnt family have been found to play a central role in controlling embryonic development from hydra to human. In the developing vertebrate limb, Wnt signaling is required for limb bud initiation, early limb patterning (which is governed by several well-characterized signaling centers), and, finally, late limb morphogenesis events. Wnt ligands are unique, in that they can activate several different receptor-mediated signal transduction pathways. The most extensively studied Wnt pathway is the canonical Wnt pathway, which controls gene expression by stabilizing beta-catenin in regulating a diverse array of biological processes. Recently, more attention has been given to the noncanonical Wnt pathway, which is beta-catenin-independent. The noncanonical Wnt pathway signals through activating Ca(2+) flux, JNK activation, and both small and heterotrimeric G proteins, to induce changes in gene expression, cell adhesion, migration, and polarity. Abnormal Wnt signaling leads to developmental defects and human diseases affecting either tissue development or homeostasis. Further understanding of the biological function and signaling mechanism of Wnt signaling is essential for the development of novel preventive and therapeutic approaches of human diseases. This review provides a critical perspective on how Wnt signaling regulates different developmental processes. As Wnt signaling in tumor formation has been reviewed extensively elsewhere, this part is not included in the review of the clinical significance of Wnt signaling.

  1. Kinase cogs go forward and reverse in the Wnt signaling machine.

    Science.gov (United States)

    Dale, Trevor

    2006-01-01

    An important link between Wnt binding at the cell surface and nuclear -catenin-TCF-dependent transcription has been made with the identification of kinases that promote the association of the Wnt receptor and -catenin turnover complexes. Surprisingly, the enzymes implicated had previously been suggested to inhibit rather than promote Wnt signaling.

  2. The Clinical Importance of Assessing Tumor Hypoxia: Relationship of Tumor Hypoxia to Prognosis and Therapeutic Opportunities

    Science.gov (United States)

    Walsh, Joseph C.; Lebedev, Artem; Aten, Edward; Madsen, Kathleen; Marciano, Liane

    2014-01-01

    I. Introduction II. The Clinical Importance of Tumor Hypoxia A. Pathophysiology of hypoxia B. Hypoxia's negative impact on the effectiveness of curative treatment 1. Hypoxic tumors accumulate and propagate cancer stem cells 2. Hypoxia reduces the effectiveness of radiotherapy 3. Hypoxia increases metastasis risk and reduces the effectiveness of surgery 4. Hypoxic tumors are resistant to the effects of chemotherapy and chemoradiation C. Hypoxia is prognostic for poor patient outcomes III. Diagnosis of Tumor Hypoxia A. Direct methods 1. Oxygen electrode—direct pO2 measurement most used in cancer research 2. Phosphorescence quenching—alternative direct pO2 measurement 3. Electron paramagnetic resonance 4. 19F-magnetic resonance spectroscopy 5. Overhauser-enhanced MRI B. Endogenous markers of hypoxia 1. Hypoxia-inducible factor-1α 2. Carbonic anhydrase IX 3. Glucose transporter 1 4. Osteopontin 5. A combined IHC panel of protein markers for hypoxia 6. Comet assay C. Physiologic methods 1. Near-infrared spectroscopy/tomography—widely used for pulse oximetry 2. Photoacoustic tomography 3. Contrast-enhanced color duplex sonography 4. MRI-based measurements 5. Blood oxygen level-dependent MRI 6. Pimonidazole 7. EF5 (pentafluorinated etanidazole) 8. Hypoxia PET imaging—physiologic hypoxia measurement providing tomographic information a. 18F-fluoromisonidazole b. 18F-fluoroazomycinarabinofuranoside c. 18F-EF5 (pentafluorinated etanidazole) d. 18F-flortanidazole e. Copper (II) (diacetyl-bis (N4-methylthiosemicarbazone)) f. 18F-FDG imaging of hypoxia IV. Modifying Hypoxia to Improve Therapeutic Outcomes A. Use of hypoxia information in radiation therapy planning B. Use of hypoxia assessment for selection of patients responsive to nimorazole C. Use of hypoxia assessment for selection of patients responsive to tirapazamine D. Use of hypoxia assessment for selection of patients

  3. Ecosystem impacts of hypoxia: thresholds of hypoxia and pathways to recovery

    International Nuclear Information System (INIS)

    Steckbauer, A; Duarte, C M; Vaquer-Sunyer, R; Carstensen, J; Conley, D J

    2011-01-01

    Coastal hypoxia is increasing in the global coastal zone, where it is recognized as a major threat to biota. Managerial efforts to prevent hypoxia and achieve recovery of ecosystems already affected by hypoxia are largely based on nutrient reduction plans. However, these managerial efforts need to be informed by predictions on the thresholds of hypoxia (i.e. the oxygen levels required to conserve biodiversity) as well as the timescales for the recovery of ecosystems already affected by hypoxia. The thresholds for hypoxia in coastal ecosystems are higher than previously thought and are not static, but regulated by local and global processes, being particularly sensitive to warming. The examination of recovery processes in a number of coastal areas managed for reducing nutrient inputs and, thus, hypoxia (Northern Adriatic; Black Sea; Baltic Sea; Delaware Bay; and Danish Coastal Areas) reveals that recovery timescales following the return to normal oxygen conditions are much longer than those of loss following the onset of hypoxia, and typically involve decadal timescales. The extended lag time for ecosystem recovery from hypoxia results in non-linear pathways of recovery due to hysteresis and the shift in baselines, affecting the oxygen thresholds for hypoxia through time.

  4. Crossroads of Wnt and Hippo in epithelial tissues.

    Science.gov (United States)

    Bernascone, Ilenia; Martin-Belmonte, Fernando

    2013-08-01

    Epithelial tissues undergo constant growth and differentiation during embryonic development and to replace damaged tissue in adult organs. These processes are governed by different signaling pathways that ultimately control the expression of genes associated with cell proliferation, patterning, and death. One essential pathway is Wnt, which controls tubulogenesis in several epithelial organs. Recently, Wnt has been closely linked to other signaling pathways, such as Hippo, that orchestrate proliferation and apoptosis to control organ size. There is evidence that epithelial cell junctions may sequester the transcription factors that act downstream of these signaling pathways, which would represent an important aspect of their functional regulation and their influence on cell behavior. Here, we review the transcriptional control exerted by the Wnt and Hippo signaling pathways during epithelial growth, patterning, and differentiation and recent advances in understanding of the regulation and crosstalk of these pathways in epithelial tissues. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Use of a molecular genetic platform technology to produce human Wnt proteins reveals distinct local and distal signaling abilities.

    Directory of Open Access Journals (Sweden)

    Jennifer L Green

    Full Text Available Functional and mechanistic studies of Wnt signaling have been severely hindered by the inaccessibility of bioactive proteins. To overcome this long-standing barrier, we engineered and characterized a panel of Chinese hamster ovary (CHO cell lines with inducible transgenes encoding tagged and un-tagged human WNT1, WNT3A, WNT5A, WNT7A, WNT11, WNT16 or the soluble Wnt antagonist Fzd8CRD, all integrated into an identical genomic locus. Using a quantitative real-time bioluminescence assay, we show that cells expressing WNT1, 3A and 7A stimulate Wnt/beta-catenin reporter activity, while the other WNT expressing cell lines interfere with this activation. Additionally, in contrast to WNT3A, WNT1 only exhibits activity when cell-associated, and thus only signals to neighboring cells. The reporter assay also revealed a rapid decline of Wnt activity at 37°C, indicating that Wnt activity is highly labile. These engineered cell lines will reduce the cost of making and purifying Wnt proteins and serve as a continuous, reliable and regulatable source of Wnts to research laboratories around the world.

  6. Non-Canonical Hedgehog Signaling Is a Positive Regulator of the WNT Pathway and Is Required for the Survival of Colon Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Joseph L. Regan

    2017-12-01

    Full Text Available Summary: Colon cancer is a heterogeneous tumor driven by a subpopulation of cancer stem cells (CSCs. To study CSCs in colon cancer, we used limiting dilution spheroid and serial xenotransplantation assays to functionally define the frequency of CSCs in a panel of patient-derived cancer organoids. These studies demonstrated cancer organoids to be enriched for CSCs, which varied in frequency between tumors. Whole-transcriptome analysis identified WNT and Hedgehog signaling components to be enhanced in CSC-enriched tumors and in aldehyde dehydrogenase (ALDH-positive CSCs. Canonical GLI-dependent Hedgehog signaling is a negative regulator of WNT signaling in normal intestine and intestinal tumors. Here, we show that Hedgehog signaling in colon CSCs is autocrine SHH-dependent, non-canonical PTCH1 dependent, and GLI independent. In addition, using small-molecule inhibitors and RNAi against SHH-palmitoylating Hedgehog acyltransferase (HHAT, we demonstrate that non-canonical Hedgehog signaling is a positive regulator of WNT signaling and required for colon CSC survival. : Colon cancer is a heterogeneous tumor driven by a subpopulation(s of therapy-resistant cancer stem cells (CSCs. Regan et al. use 3D culture models to demonstrate that CSC survival is regulated by non-canonical, SHH-dependent, PTCH1-dependent Hedgehog signaling, which acts as a positive regulator of WNT signaling to block CSC differentiation. Keywords: WNT pathway, non-canonical Hedgehog signaling, cancer stem cell, colon cancer, cancer organoid, PTCH1, HHAT, SHH

  7. Multi-level interactions between the nuclear receptor TRα1 and the WNT effectors β-catenin/Tcf4 in the intestinal epithelium.

    Directory of Open Access Journals (Sweden)

    Maria Sirakov

    Full Text Available Intestinal homeostasis results from complex cross-regulation of signaling pathways; their alteration induces intestinal tumorigenesis. Previously, we found that the thyroid hormone nuclear receptor TRα1 activates and synergizes with the WNT pathway, inducing crypt cell proliferation and promoting tumorigenesis. Here, we investigated the mechanisms and implications of the cross-regulation between these two pathways in gut tumorigenesis in vivo and in vitro. We analyzed TRα1 and WNT target gene expression in healthy mucosae and tumors from mice overexpressing TRα1 in the intestinal epithelium in a WNT-activated genetic background (vil-TRα1/Apc mice. Interestingly, increased levels of β-catenin/Tcf4 complex in tumors from vil-TRα1/Apc mice blocked TRα1 transcriptional activity. This observation was confirmed in Caco2 cells, in which TRα1 functionality on a luciferase reporter-assay was reduced by the overexpression of β-catenin/Tcf4. Moreover, TRα1 physically interacted with β-catenin/Tcf4 in the nuclei of these cells. Using molecular approaches, we demonstrated that the binding of TRα1 to its DNA target sequences within the tumors was impaired, while it was newly recruited to WNT target genes. In conclusion, our observations strongly suggest that increased β-catenin/Tcf4 levels i correlated with reduced TRα1 transcriptional activity on its target genes and, ii were likely responsible for the shift of TRα1 binding on WNT targets. Together, these data suggest a novel mechanism for the tumor-promoting activity of the TRα1 nuclear receptor.

  8. Rational design of DKK3 structure-based small peptides as antagonists of Wnt signaling pathway and in silico evaluation of their efficiency.

    Directory of Open Access Journals (Sweden)

    Mansour Poorebrahim

    Full Text Available Dysregulated Wnt signaling pathway is highly associated with the pathogenesis of several human cancers. Dickkopf proteins (DKKs are thought to inhibit Wnt signaling pathway through binding to lipoprotein receptor-related protein (LRP 5/6. In this study, based on the 3-dimensional (3D structure of DKK3 Cys-rich domain 2 (CRD2, we have designed and developed several peptide inhibitors of Wnt signaling pathway. Modeller 9.15 package was used to predict 3D structure of CRD2 based on the Homology modeling (HM protocol. After refinement and minimization with GalaxyRefine and NOMAD-REF servers, the quality of selected models was evaluated utilizing VADAR, SAVES and ProSA servers. Molecular docking studies as well as literature-based information revealed two distinct boxes located at CRD2 which are actively involved in the DKK3-LRP5/6 interaction. A peptide library was constructed conducting the backrub sequence tolerance scanning protocol in Rosetta3.5 according to the DKK3-LRP5/6 binding sites. Seven tolerated peptides were chosen and their binding affinity and stability were improved by some logical amino acid substitutions. Molecular dynamics (MD simulations of peptide-LRP5/6 complexes were carried out using GROMACS package. After evaluation of binding free energies, stability, electrostatic potential and some physicochemical properties utilizing computational approaches, three peptides (PEP-I1, PEP-I3 and PEP-II2 demonstrated desirable features. However, all seven improved peptides could sufficiently block the Wnt-binding site of LRP6 in silico. In conclusion, we have designed and improved several small peptides based on the LRP6-binding site of CRD2 of DKK3. These peptides are highly capable of binding to LRP6 in silico, and may prevent the formation of active Wnt-LRP6-Fz complex.

  9. Hypoxia inducible factor-1α-dependent epithelial to mesenchymal transition under hypoxic conditions in prostate cancer cells.

    Science.gov (United States)

    Li, Mingchuan; Wang, Yong Xing; Luo, Yong; Zhao, Jiahui; Li, Qing; Zhang, Jiao; Jiang, Yongguang

    2016-07-01

    Prostate cancer is the most commonly diagnosed cancer in men and the second leading cause of cancer death. Hypoxia is an environmental stimulus that plays an important role in the development and cancer progression especially for solid tumors. The key regulator under hypoxic conditions is stabilized hypoxia-inducible factor (HIF)-1α. In the present study, immune-fluorescent staining, siRNAs, qRT-PC, immunoblotting, cell migration and invasion assays were carried out to test typical epithelial to mesenchymal transition under hypoxia and the key regulators of this process in PC3, a human prostate cancer cell line. Our data demonstrated that hypoxia induces diverse molecular, phenotypic and functional changes in prostate cancer cells that are consistent with EMT. We also showed that a cell signal factor such as HIF-1α, which might be stabilized under hypoxic environment, is involved in EMT and cancer cell invasive potency. The induced hypoxia could be blocked by HIF-1α gene silencing and reoxygenation of EMT in prostate cancer cells, hypoxia partially reversed accompanied by a process of mesenchymal-epithelial reverting transition (MErT). EMT might be induced by activation of HIF-1α-dependent cell signaling in hypoxic prostate cancer cells.

  10. IBMX protects human proximal tubular epithelial cells from hypoxic stress through suppressing hypoxia-inducible factor-1α expression.

    Science.gov (United States)

    Hasan, Arif Ul; Kittikulsuth, Wararat; Yamaguchi, Fuminori; Musarrat Ansary, Tuba; Rahman, Asadur; Shibayama, Yuki; Nakano, Daisuke; Hitomi, Hirofumi; Tokuda, Masaaki; Nishiyama, Akira

    2017-09-15

    Hypoxia predisposes renal fibrosis. This study was conducted to identify novel approaches to ameliorate the pathogenic effect of hypoxia. Using human proximal tubular epithelial cells we showed that a pan-phosphodiesterase (PDE) inhibitor, 3-isobutyl-1-methylxanthine (IBMX) dose and time dependently downregulated hypoxia-inducible factor 1α (HIF-1α) mRNA expression, which was further augmented by addition of a transcriptional inhibitor, actinomycin D. IBMX also increased the cellular cyclic adenosine monophosphate (cAMP) level. Luciferase assay showed that blocking of protein kinase A (PKA) using H89 reduced, while 8-Br-cAMP agonized the repression of HIF-1α promoter activity in hypoxic condition. Deletion of cAMP response element binding sites from the HIF-1α promoter abrogated the effect of IBMX. Western blot and immunofluorescent study confirmed that the CoCl 2 induced increased HIF-1α protein in whole cell lysate and in nucleus was reduced by the IBMX. Through this process, IBMX attenuated both CoCl 2 and hypoxia induced mRNA expressions of two pro-fibrogenic factors, platelet-derived growth factor B and lysyl oxidase. Moreover, IBMX reduced production of a mesenchymal transformation factor, β-catenin; as well as protected against hypoxia induced cell-death. Taken together, our study showed novel evidence that the PDE inhibitor IBMX can downregulate the transcription of HIF-1α, and thus may attenuate hypoxia induced renal fibrosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Neutralizing S1P inhibits intratumoral hypoxia, induces vascular remodelling and sensitizes to chemotherapy in prostate cancer

    Science.gov (United States)

    Ader, Isabelle; Golzio, Muriel; Andrieu, Guillaume; Zalvidea, Santiago; Richard, Sylvain; Sabbadini, Roger A.; Malavaud, Bernard; Cuvillier, Olivier

    2015-01-01

    Hypoxia promotes neovascularization, increased tumor growth, and therapeutic resistance. The transcription factor, hypoxia-inducible factor 1α (HIF-1α), has been reported as the master driver of adaptation to hypoxia. We previously identified the sphingosine kinase 1/sphingosine 1-phosphate (SphK1/S1P) pathway as a new modulator of HIF-1α under hypoxia. Taking advantage of a monoclonal antibody neutralizing extracellular S1P (sphingomab), we report that inhibition of S1P extracellular signaling blocks HIF-1α accumulation and activity in several cancer cell models exposed to hypoxia. In an orthotopic xenograft model of prostate cancer, we show that sphingomab reduces hypoxia and modifies vessel architecture within 5 days of treatment, leading to increased intratumoral blood perfusion. Supporting the notion that a transient vascular normalization of tumor vessels is the mechanism by which sphingomab exerts its effects, we demonstrate that administration of the antibody for 5 days before chemotherapy is more effective at local tumor control and metastatic dissemination than any other treatment scheduling. These findings validate sphingomab as a potential new normalization agent that could contribute to successful sensitization of hypoxic tumors to chemotherapy. PMID:25915662

  12. Paracrine Activation of the Wnt/β-Catenin Pathway by Bone Marrow Stem Cell Attenuates Cisplatin-Induced Kidney Injury

    Directory of Open Access Journals (Sweden)

    Xiaoyan Jiao

    2017-12-01

    Full Text Available Background/Aims: Cisplatin-induced acute kidney injury (AKI involves damage to tubular cells via excess reactive oxygen species (ROS generation. Stem cell-based therapies have shown great promise in AKI treatment. In this study, we aimed to assess the protective effect and mechanism of bone marrow mesenchymal stem cell (BMSC-derived conditioned medium (CM against cisplatin-induced AKI. Methods: In vitro, NRK-52E cells were incubated with cisplatin in the presence or absence of CM, followed by the assessment of cell viability, apoptosis and cell cycle distribution. Then, ICG-001 and IWR-1 were used to inhibit the wnt/β-catenin pathway. Furthermore, intracellular and mitochondrial ROS levels were evaluated using DCFH-DA and MitoSOX, respectively. In vivo, after cisplatin injection, rats were intravenously injected with CM or BMSCs. Sera and kidney tissues were collected on day 3 after cisplatin injection to evaluate changes in renal function and histology. Western blotting and qRT-PCR were employed to determine the expression of wnt/β-catenin pathway-related genes and proteins. Immunohistochemical staining was used to evaluate tubular β-catenin expression in kidney biopsy from AKI patients. Results: CM protected NRK-52E cells from cisplatin-induced injury by restoring the wnt4/β-catenin pathway. In response to ICG-001 and IWR-1, the protective effect of CM was attenuated, characterized by a decrease in cell proliferation and an increase in cell apoptosis and intracellular and mitochondrial ROS levels. Knockdown of β-catenin using siRNAs also suppressed the mitochondrial biogenesis regulators PGC-1α, TFAM and NRF-1. In the rat model, CM significantly alleviated renal function and histology associated with tubular injury and upregulated wnt4 and β-catenin. However, the renoprotective effect of CM was blocked by ICG-001, characterized by exacerbated renal function, suppressed PGC-1α expression and increased mitochondrial ROS. Clinical data

  13. Paracrine Activation of the Wnt/β-Catenin Pathway by Bone Marrow Stem Cell Attenuates Cisplatin-Induced Kidney Injury.

    Science.gov (United States)

    Jiao, Xiaoyan; Cai, Jieru; Yu, Xiaofang; Ding, Xiaoqiang

    2017-01-01

    Cisplatin-induced acute kidney injury (AKI) involves damage to tubular cells via excess reactive oxygen species (ROS) generation. Stem cell-based therapies have shown great promise in AKI treatment. In this study, we aimed to assess the protective effect and mechanism of bone marrow mesenchymal stem cell (BMSC)-derived conditioned medium (CM) against cisplatin-induced AKI. In vitro, NRK-52E cells were incubated with cisplatin in the presence or absence of CM, followed by the assessment of cell viability, apoptosis and cell cycle distribution. Then, ICG-001 and IWR-1 were used to inhibit the wnt/β-catenin pathway. Furthermore, intracellular and mitochondrial ROS levels were evaluated using DCFH-DA and MitoSOX, respectively. In vivo, after cisplatin injection, rats were intravenously injected with CM or BMSCs. Sera and kidney tissues were collected on day 3 after cisplatin injection to evaluate changes in renal function and histology. Western blotting and qRT-PCR were employed to determine the expression of wnt/β-catenin pathway-related genes and proteins. Immunohistochemical staining was used to evaluate tubular β-catenin expression in kidney biopsy from AKI patients. CM protected NRK-52E cells from cisplatin-induced injury by restoring the wnt4/β-catenin pathway. In response to ICG-001 and IWR-1, the protective effect of CM was attenuated, characterized by a decrease in cell proliferation and an increase in cell apoptosis and intracellular and mitochondrial ROS levels. Knockdown of β-catenin using siRNAs also suppressed the mitochondrial biogenesis regulators PGC-1α, TFAM and NRF-1. In the rat model, CM significantly alleviated renal function and histology associated with tubular injury and upregulated wnt4 and β-catenin. However, the renoprotective effect of CM was blocked by ICG-001, characterized by exacerbated renal function, suppressed PGC-1α expression and increased mitochondrial ROS. Clinical data showed that the tubular β-catenin level was lower in

  14. Kinetic modeling in PET imaging of hypoxia

    DEFF Research Database (Denmark)

    Li, Fan; Jørgensen, Jesper Tranekjær; Hansen, Anders E

    2014-01-01

    be used for non-invasive mapping of tissue oxygenation in vivo and several hypoxia specific PET tracers have been developed. Evaluation of PET data in the clinic is commonly based on visual assessment together with semiquantitative measurements e.g. standard uptake value (SUV). However, dynamic PET......Tumor hypoxia is associated with increased therapeutic resistance leading to poor treatment outcome. Therefore the ability to detect and quantify intratumoral oxygenation could play an important role in future individual personalized treatment strategies. Positron Emission Tomography (PET) can...... analysis for PET imaging of hypoxia....

  15. Wise, a context-dependent activator and inhibitor of Wnt signalling.

    Science.gov (United States)

    Itasaki, Nobue; Jones, C Michael; Mercurio, Sara; Rowe, Alison; Domingos, Pedro M; Smith, James C; Krumlauf, Robb

    2003-09-01

    We have isolated a novel secreted molecule, Wise, by a functional screen for activities that alter the anteroposterior character of neuralised Xenopus animal caps. Wise encodes a secreted protein capable of inducing posterior neural markers at a distance. Phenotypes arising from ectopic expression or depletion of Wise resemble those obtained when Wnt signalling is altered. In animal cap assays, posterior neural markers can be induced by Wnt family members, and induction of these markers by Wise requires components of the canonical Wnt pathway. This indicates that in this context Wise activates the Wnt signalling cascade by mimicking some of the effects of Wnt ligands. Activation of the pathway was further confirmed by nuclear accumulation of beta-catenin driven by Wise. By contrast, in an assay for secondary axis induction, extracellularly Wise antagonises the axis-inducing ability of Wnt8. Thus, Wise can activate or inhibit Wnt signalling in a context-dependent manner. The Wise protein physically interacts with the Wnt co-receptor, lipoprotein receptor-related protein 6 (LRP6), and is able to compete with Wnt8 for binding to LRP6. These activities of Wise provide a new mechanism for integrating inputs through the Wnt coreceptor complex to modulate the balance of Wnt signalling.

  16. Activation of Wnt Planar Cell Polarity (PCP) signaling promotes growth plate column formation in vitro.

    Science.gov (United States)

    Randall, Rachel M; Shao, Yvonne Y; Wang, Lai; Ballock, R Tracy

    2012-12-01

    Disrupting the Wnt Planar Cell Polarity (PCP) signaling pathway in vivo results in loss of columnar growth plate architecture, but it is unknown whether activation of this pathway in vitro is sufficient to promote column formation. We hypothesized that activation of the Wnt PCP pathway in growth plate chondrocyte cell pellets would promote columnar organization in these cells that are normally oriented randomly in culture. Rat growth plate chondrocytes were transfected with plasmids encoding the Fzd7 cell-surface Wnt receptor, a Fzd7 deletion mutant lacking the Wnt-binding domain, or Wnt receptor-associated proteins Ror2 or Vangl2, and then cultured as three-dimensional cell pellets in the presence of recombinant Wnt5a or Wnt5b for 21 days. Cellular morphology was evaluated using histomorphometric measurements. Activation of Wnt PCP signaling components promoted the initiation of columnar morphogenesis in the chondrocyte pellet culture model, as measured by histomorphometric analysis of the column index (ANOVA p = 0.01). Activation of noncanonical Wnt signaling through overexpression of both the cell-surface Wnt receptor Fzd7 and receptor-associated protein Ror2 with addition of recombinant Wnt5a promotes the initiation of columnar architecture of growth plate chondrocytes in vitro, representing an important step toward growth plate regeneration. Copyright © 2012 Orthopaedic Research Society.

  17. Cell intrinsic modulation of Wnt signaling controls neuroblast migration in C. elegans.

    Science.gov (United States)

    Mentink, Remco A; Middelkoop, Teije C; Rella, Lorenzo; Ji, Ni; Tang, Chung Yin; Betist, Marco C; van Oudenaarden, Alexander; Korswagen, Hendrik C

    2014-10-27

    Members of the Wnt family of secreted signaling proteins are key regulators of cell migration and axon guidance. In the nematode C. elegans, the migration of the QR neuroblast descendants requires multiple Wnt ligands and receptors. We found that the migration of the QR descendants is divided into three sequential phases that are each mediated by a distinct Wnt signaling mechanism. Importantly, the transition from the first to the second phase, which is the main determinant of the final position of the QR descendants along the anteroposterior body axis, is mediated through a cell-autonomous process in which the time-dependent expression of a Wnt receptor turns on the canonical Wnt/β-catenin signaling response that is required to terminate long-range anterior migration. Our results show that, in addition to direct guidance of cell migration by Wnt morphogenic gradients, cell migration can also be controlled indirectly through cell-intrinsic modulation of Wnt signaling responses.

  18. Secreted Wnt antagonists in leukemia: A road yet to be paved.

    Science.gov (United States)

    Pehlivan, Melek; Çalışkan, Ceyda; Yüce, Zeynep; Sercan, Hakki Ogun

    2018-03-28

    Wnt signaling has been a topic of research for many years for its diverse and fundamental functions in physiological (such as embryogenesis, organogenesis, proliferation, tissue repair and cellular differentiation) and pathological (carcinogenesis, congenital/genetic diseases, and tissue degeneration) processes. Wnt signaling pathway aberrations are associated with both solid tumors and hematological malignancies. Unregulated Wnt signaling observed in malignancies may be due to a wide spectrum of abnormalities, from mutations in the genes of key players to epigenetic modifications of Wnt antagonists. Of these, Wnt antagonists are gaining significant attention for their potential of being targets for treatment and inhibition of Wnt signaling. In this review, we discuss and summarize the significance of Wnt signaling antagonists in the pathogenesis and treatment of hematological malignancies. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Wnt-10b, uniquely among Wnts, promotes epithelial differentiation and shaft growth

    International Nuclear Information System (INIS)

    Ouji, Yukiteru; Yoshikawa, Masahide; Moriya, Kei; Nishiofuku, Mariko; Matsuda, Ryosuke; Ishizaka, Shigeaki

    2008-01-01

    Although Wnts are expressed in hair follicles throughout life from embryo to adult, and considered to be critical for their development and maturation, their roles remain largely unknown. In the present study, we investigated the effects of Wnts (Wnt-3a, Wnt-5a, Wnt-10b, and Wnt-11) on epithelial cell differentiation using adult mouse-derived primary skin epithelial cell (MPSEC) cultures and hair growth using hair follicle organ cultures. Only Wnt-10b showed evident promotion of epithelial cell differentiation and hair shaft growth, in contrast to Wnt-3a, 5a, and 11. Our results suggest that Wnt-10b is unique and plays an important role in differentiation of epithelial cells in the hair follicle

  20. Wnt-10b promotes differentiation of skin epithelial cells in vitro

    International Nuclear Information System (INIS)

    Ouji, Yukiteru; Yoshikawa, Masahide; Shiroi, Akira; Ishizaka, Shigeaki

    2006-01-01

    To evaluate the role of Wnt-10b in epithelial differentiation, we investigated the effects of Wnt-10b on adult mouse-derived primary skin epithelial cells (MPSEC). Recombinant Wnt-10b protein (rWnt-10b) was prepared using a gene engineering technique and MPSEC were cultured in its presence, which resulted in morphological changes from cuboidal to spindle-shaped and inhibited their proliferation. Further, involvement of the canonical Wnt signal pathway was also observed. MPSEC treated with rWnt-10b showed characteristics of the hair shaft and inner root sheath of the hair follicle, in results of Ayoub Shklar staining and immunocytochemistry. Further, the cells expressed mRNA for differentiated epithelial cells, including keratin 1, keratin 2, loricrin, mHa5, and mHb5, in association with a decreased expression of the basal cell marker keratin 5. These results suggest that Wnt-10b promotes the differentiation of MPSEC

  1. Human erythropoietin response to hypocapnic hypoxia, normocapnic hypoxia, and hypocapnic normoxia

    DEFF Research Database (Denmark)

    Klausen, T; Christensen, H; Hansen, J M

    1996-01-01

    exposed to 2 h each of hypocapnic hypoxia, normocapnic hypoxia, hypocapnic normoxia, and normal breathing of room air (control experiment). During the control experiment, serum-EPO showed significant variations (ANOVA P = 0.047) with a 15% increase in mean values. The serum-EPO measured in the other...... (10% Co2 with 10% O2) to the hypoxic gas mixture. This elicited an increased ventilation, unaltered arterial pH and haemoglobin oxygen affinity, a lower degree of hypoxia than during hypocapnic hypoxia, and no significant changes in serum-EPO (ANOVA P > 0.05). Hypocapnic normoxia, produced...

  2. An efficient, block-by-block algorithm for inverting a block tridiagonal, nearly block Toeplitz matrix

    International Nuclear Information System (INIS)

    Reuter, Matthew G; Hill, Judith C

    2012-01-01

    We present an algorithm for computing any block of the inverse of a block tridiagonal, nearly block Toeplitz matrix (defined as a block tridiagonal matrix with a small number of deviations from the purely block Toeplitz structure). By exploiting both the block tridiagonal and the nearly block Toeplitz structures, this method scales independently of the total number of blocks in the matrix and linearly with the number of deviations. Numerical studies demonstrate this scaling and the advantages of our method over alternatives.

  3. Paeoniflorin prevents hypoxia-induced epithelial–mesenchymal transition in human breast cancer cells

    Directory of Open Access Journals (Sweden)

    Zhou Z

    2016-04-01

    Full Text Available Zhenyu Zhou,1,* Shunchang Wang,1,* Caijuan Song,2 Zhuang Hu11Department of Thyroid and Breast, Huaihe Hospital, Henan University, Kaifeng, 2Department of Immunization Program, Zhengzhou Center for Disease Control and Prevention, Zhengzhou, People’s Republic of China*These authors contributed equally to this workAbstract: Paeoniflorin (PF is a monoterpene glycoside extracted from the root of Paeonia lactiflora Pall. Previous studies have demonstrated that PF inhibits the growth, invasion, and metastasis of tumors in vivo and in vitro. However, the effect of PF on hypoxia-induced epithelial–mesenchymal transition (EMT in breast cancer cells remains unknown. Therefore, the objective of this study was to investigate the effect of PF on hypoxia-induced EMT in breast cancer cells, as well as characterize the underlying mechanism. The results presented in this study demonstrate that PF blocks the migration and invasion of breast cancer cells by repressing EMT under hypoxic conditions. PF also significantly attenuated the hypoxia-induced increase in HIF-1α level. Furthermore, PF prevented hypoxia-induced expression of phosphorylated PI3K and Akt in MDA-MB-231 cells. In conclusion, PF prevented hypoxia-induced EMT in breast cancer cells by inhibiting HIF-1α expression via modulation of PI3K/Akt signaling pathway. This finding provides evidence that PF can serve as a therapeutic agent for the treatment of breast cancer.Keywords: paeoniflorin, breast cancer, hypoxia, epithelial–mesenchymal transition, PI3K/Akt signaling pathway

  4. Hypoxia and the heart of poikilotherms

    Czech Academy of Sciences Publication Activity Database

    Ošťádal, Bohuslav

    2014-01-01

    Roč. 1, č. 1 (2014), s. 28-32 Institutional support: RVO:67985823 Keywords : blood supply heart * poikilotherms * tolerance to hypoxia Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery

  5. Redox signaling during hypoxia in mammalian cells

    Directory of Open Access Journals (Sweden)

    Kimberly A. Smith

    2017-10-01

    Full Text Available Hypoxia triggers a wide range of protective responses in mammalian cells, which are mediated through transcriptional and post-translational mechanisms. Redox signaling in cells by reactive oxygen species (ROS such as hydrogen peroxide (H2O2 occurs through the reversible oxidation of cysteine thiol groups, resulting in structural modifications that can change protein function profoundly. Mitochondria are an important source of ROS generation, and studies reveal that superoxide generation by the electron transport chain increases during hypoxia. Other sources of ROS, such as the NAD(PH oxidases, may also generate oxidant signals in hypoxia. This review considers the growing body of work indicating that increased ROS signals during hypoxia are responsible for regulating the activation of protective mechanisms in diverse cell types.

  6. Hypoxia, HIF-1 Regulation and Cancer Therapy

    NARCIS (Netherlands)

    Groot, A.J.

    2008-01-01

    Oxygen insufficiency (hypoxia) is a common feature of human cancer and associated with tumor aggressiveness and poor clinical outcome. Furthermore, hypoxic tumors are more resistant to ionizing radiation and chemotherapy contributing to their unfavorable prognosis. The oxygen sensing pathway is

  7. 2007 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  8. 2004 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  9. 2005 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  10. 2002 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  11. 2003 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  12. 2001 Hypoxia Watch Bottom CTD Station Locations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Hypoxia Watch project provides near-real-time, web-based maps of dissolved oxygen near the sea floor over the Texas-Louisiana continental shelf during a...

  13. Analysis of Block OMP using Block RIP

    OpenAIRE

    Wang, Jun; Li, Gang; Zhang, Hao; Wang, Xiqin

    2011-01-01

    Orthogonal matching pursuit (OMP) is a canonical greedy algorithm for sparse signal reconstruction. When the signal of interest is block sparse, i.e., it has nonzero coefficients occurring in clusters, the block version of OMP algorithm (i.e., Block OMP) outperforms the conventional OMP. In this paper, we demonstrate that a new notion of block restricted isometry property (Block RIP), which is less stringent than standard restricted isometry property (RIP), can be used for a very straightforw...

  14. Canonical wnt signaling regulates atrioventricular junction programming and electrophysiological properties

    NARCIS (Netherlands)

    Gillers, Benjamin S.; Chiplunkar, Aditi; Aly, Haytham; Valenta, Tomas; Basler, Konrad; Christoffels, Vincent M.; Efimov, Igor R.; Boukens, Bastiaan J.; Rentschler, Stacey

    2015-01-01

    Proper patterning of the atrioventricular canal (AVC) is essential for delay of electrical impulses between atria and ventricles, and defects in AVC maturation can result in congenital heart disease. To determine the role of canonical Wnt signaling in the myocardium during AVC development. We used a

  15. Mammary Development and Breast Cancer: A Wnt Perspective

    Science.gov (United States)

    Yu, Qing Cissy; Verheyen, Esther M.; Zeng, Yi Arial

    2016-01-01

    The Wnt pathway has emerged as a key signaling cascade participating in mammary organogenesis and breast oncogenesis. In this review, we will summarize the current knowledge of how the pathway regulates stem cells and normal development of the mammary gland, and discuss how its various components contribute to breast carcinoma pathology. PMID:27420097

  16. WNT/β-Catenin Signaling in Vertebrate Eye Development

    Czech Academy of Sciences Publication Activity Database

    Fujimura, Naoko

    2016-01-01

    Roč. 4, November (2016), č. článku 138. ISSN 2296-634X R&D Projects: GA MŠk(CZ) LQ1604 Institutional support: RVO:68378050 Keywords : retina * WNT * b-catenin * development * differentiation Subject RIV: EB - Genetics ; Molecular Biology

  17. Epigenetic regulation of the Hedgehog and Wnt pathways in cancer

    NARCIS (Netherlands)

    Wils, Leon J.; Bijlsma, Maarten F.

    2018-01-01

    The Hedgehog (Hh) and wingless-Int1 (Wnt) pathways are important for tissue patterning in the developing embryo. In adult tissue, both pathways are typically dormant but are activated under certain conditions such as tissue damage. Aberrant activation of these pathways by mutations in key pathway

  18. Cross-talk between insulin and Wnt signaling in preadipocytes

    DEFF Research Database (Denmark)

    Palsgaard, Jane; Emanuelli, Brice; Winnay, Jonathon N

    2012-01-01

    and appears to be due to an inducible interaction between LRP5 and the insulin receptor as demonstrated by co-immunoprecipitation. These data demonstrate that Wnt and insulin signaling pathways exhibit cross-talk at multiple levels. Wnt induces phosphorylation of Akt, ERK1/2, and GSK3β, and this is dependent...... and LRP6 and with and without knock-out of insulin and IGF-1 receptors. We find that Wnt stimulation leads to phosphorylation of insulin signaling key mediators, including Akt, GSK3β, and ERK1/2, although with a lower fold stimulation and slower time course than observed for insulin. These Wnt effects...... are insulin/IGF-1 receptor-dependent and are lost in insulin/IGF-1 receptor double knock-out cells. Conversely, in LRP5 knockdown preadipocytes, insulin-induced phosphorylation of IRS1, Akt, GSK3β, and ERK1/2 is highly reduced. This effect is specific to insulin, as compared with IGF-1, stimulation...

  19. Wnt signaling in adult intestinal stem cells and cancer

    Czech Academy of Sciences Publication Activity Database

    Krausová, Michaela; Kořínek, Vladimír

    2014-01-01

    Roč. 26, č. 3 (2014), s. 570-579 ISSN 0898-6568 R&D Projects: GA ČR GAP305/12/2347; GA ČR GAP305/11/1780 Institutional support: RVO:68378050 Keywords : Wnt * intestine * cancer Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.315, year: 2014

  20. Fatty acid modification of Wnt1 and Wnt3a at serine is prerequisite for lipidation at cysteine and is essential for Wnt signalling

    Czech Academy of Sciences Publication Activity Database

    Doubravská, Lenka; Krausová, Michaela; Gradl, D.; Vojtěchová, Martina; Tůmová, Lucie; Lukáš, Jan; Valenta, Tomáš; Pospíchalová, Vendula; Fafílek, Bohumil; Plachý, Jiří; Sebesta, O.; Kořínek, Vladimír

    2011-01-01

    Roč. 23, č. 5 (2011), s. 837-848 ISSN 0898-6568 R&D Projects: GA ČR(CZ) GA204/07/1567; GA MŠk 1M0506 Institutional research plan: CEZ:AV0Z50520514 Keywords : Wnt signaling * post-translational modification * acylation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.058, year: 2011

  1. Cognition Effects of Low-Grade Hypoxia

    Science.gov (United States)

    2016-07-01

    human short-term memory . Br J Anaesth. 1971; 43(6):548–552. 3. Crow TJ, Kelman GR. Psychological effects of mild acute hypoxia. Br J Anaesth. 1973; 45...Journal Article 3. DATES COVERED (From – To) Jan 2003 – Sep 2005 4. TITLE AND SUBTITLE Cognition Effects of Low-Grade Hypoxia 5a. CONTRACT NUMBER... cognitive function are reported in this paper. The study compared cognitive function during short exposures at four different altitudes. Ninety-one

  2. Hypoxia independent drivers of melanoma angiogenesis

    Directory of Open Access Journals (Sweden)

    Svenja eMeierjohann

    2015-05-01

    Full Text Available Tumor angiogenesis is a process which is traditionally regarded as the tumor`s response to low nutrient supply occurring under hypoxic conditions. However, hypoxia is not a prerequisite for angiogenesis. The fact that even single tumor cells or small tumor cell aggregates are capable of attracting blood vessels reveals the early metastatic capability of tumor cells. This review sheds light on the hypoxia independent mechanisms of tumor angiogenesis in melanoma.

  3. Wnt signaling in form deprivation myopia of the mice retina.

    Directory of Open Access Journals (Sweden)

    Mingming Ma

    Full Text Available BACKGROUND: The canonical Wnt signaling pathway plays important roles in cellular proliferation and differentiation, axonal outgrowth, cellular maintenance in retinas. Here we test the hypothesis that elements of the Wnt signaling pathway are involved in the regulation of eye growth and prevention of myopia, in the mouse form-deprivation myopia model. METHODOLOGY/PRINCIPAL FINDINGS: (1 One hundred twenty-five C57BL/6 mice were randomly distributed into form-deprivation myopia and control groups. Form-deprivation myopia (FDM was induced by suturing the right eyelid, while the control group received no treatment. After 1, 2, and 4 weeks of treatment, eyes were assessed in vivo by cycloplegic retinoscopic refraction and axial length measurement by photography or A-scan ultrasonography. Levels of retinal Wnt2b, Fzd5 and β-catenin mRNA and protein were evaluated using RT-PCR and western blotting, respectively. (2 Another 96 mice were divided into three groups: control, drugs-only, and drugs+FDM (by diffuser. Experimentally treated eyes in the last two groups received intravitreal injections of vehicle or the proteins, DKK-1 (Wnt-pathway antagonist or Norrin (Wnt-pathway agonist, once every three days, for 4 injections total. Axial length and retinoscopic refraction were measured on the 14th day of form deprivation. Following form-deprivation for 1, 2, and 4 weeks, FDM eyes had a relatively myopic refractive error, compared with contralateral eyes. There were no significant differences in refractive error between right and left eye in control group. The amounts of Wnt2b, Fzd5 and β-catenin mRNA and protein were significantly greater in form-deprived myopia eyes than in control eyes.DKK-1 (antagonist reduced the myopic shift in refractive error and increase in axial elongation, whereas Norrin had the opposite effect in FDM eyes. CONCLUSIONS/SIGNIFICANCE: Our studies provide the first evidence that the Wnt2b signaling pathway may play a role in the

  4. Cinnamic aldehyde suppresses hypoxia-induced angiogenesis via inhibition of hypoxia-inducible factor-1α expression during tumor progression.

    Science.gov (United States)

    Bae, Woom-Yee; Choi, Jae-Sun; Kim, Ja-Eun; Jeong, Joo-Won

    2015-11-01

    During tumor progression, hypoxia-inducible factor 1 (HIF-1) plays a critical role in tumor angiogenesis and tumor growth by regulating the transcription of several genes in response to a hypoxic environment and changes in growth factors. This study was designed to investigate the effects of cinnamic aldehyde (CA) on tumor growth and angiogenesis and the mechanisms underlying CA's anti-angiogenic activities. We found that CA administration inhibits tumor growth and blocks tumor angiogenesis in BALB/c mice. In addition, CA treatment decreased HIF-1α protein expression and vascular endothelial growth factor (VEGF) expression in mouse tumors and Renca cells exposed to hypoxia in vitro. Interestingly, CA treatment did not affect the stability of von Hippel-Lindau protein (pVHL)-associated HIF-1α and CA attenuated the activation of mammalian target of rapamycin (mTOR) pathway. Collectively, these findings strongly indicate that the anti-angiogenic activity of CA is, at least in part, regulated by the mTOR pathway-mediated suppression of HIF-1α protein expression and these findings suggest that CA may be a potential drug for human cancer therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Wnt3a upregulates brain-derived insulin by increasing NeuroD1 via Wnt/β-catenin signaling in the hypothalamus.

    Science.gov (United States)

    Lee, Jaemeun; Kim, Kyungchan; Yu, Seong-Woon; Kim, Eun-Kyoung

    2016-03-08

    Insulin plays diverse roles in the brain. Although insulin produced by pancreatic β-cells that crosses the blood-brain barrier is a major source of brain insulin, recent studies suggest that insulin is also produced locally within the brain. However, the mechanisms underlying the production of brain-derived insulin (BDI) are not yet known. Here, we examined the effect of Wnt3a on BDI production in a hypothalamic cell line and hypothalamic tissue. In N39 hypothalamic cells, Wnt3a treatment significantly increased the expression of the Ins2 gene, which encodes the insulin isoform predominant in the mouse brain, by activating Wnt/β-catenin signaling. The concentration of insulin was higher in culture medium of Wnt3a-treated cells than in that of untreated cells. Interestingly, neurogenic differentiation 1 (NeuroD1), a target of Wnt/β-catenin signaling and one of transcription factors for insulin, was also induced by Wnt3a treatment in a time- and dose-dependent manner. In addition, the treatment of BIO, a GSK3 inhibitor, also increased the expression of Ins2 and NeuroD1. Knockdown of NeuroD1 by lentiviral shRNAs reduced the basal expression of Ins2 and suppressed Wnt3a-induced Ins2 expression. To confirm the Wnt3a-induced increase in Ins2 expression in vivo, Wnt3a was injected into the hypothalamus of mice. Wnt3a increased the expression of NeuroD1 and Ins2 in the hypothalamus in a manner similar to that observed in vitro. Taken together, these results suggest that BDI production is regulated by the Wnt/β-catenin/NeuroD1 pathway in the hypothalamus. Our findings will help to unravel the regulation of BDI production in the hypothalamus.

  6. Inhibition of Wnt/β-catenin signaling by a soluble collagen-derived frizzled domain interacting with Wnt3a and the receptors frizzled 1 and 8.

    Directory of Open Access Journals (Sweden)

    Ismaïl Hendaoui

    Full Text Available The Wnt/β-catenin pathway controls cell proliferation, death and differentiation. Several families of extracellular proteins can antagonize Wnt/β-catenin signaling, including the decoy receptors known as secreted frizzled related proteins (SFRPs, which have a cysteine-rich domain (CRD structurally similar to the extracellular Wnt-binding domain of the frizzled receptors. SFRPs inhibit Wnt signaling by sequestering Wnts through the CRD or by forming inactive complexes with the frizzled receptors. Other endogenous molecules carrying frizzled CRDs inhibit Wnt signaling, such as V3Nter, which is proteolytically derived from the cell surface component collagen XVIII and contains a biologically active frizzled domain (FZC18 inhibiting in vivo cell proliferation and tumor growth in mice. We recently showed that FZC18 expressing cells deliver short-range signals to neighboring cells, decreasing their proliferation in vitro and in vivo through the Wnt/β-catenin signaling pathway. Here, using low concentrations of soluble FZC18 and Wnt3a, we show that they physically interact in a cell-free system. In addition, soluble FZC18 binds the frizzled 1 and 8 receptors' CRDs, reducing cell sensitivity to Wnt3a. Conversely, inhibition of Wnt/β-catenin signaling was partially rescued by the expression of full-length frizzled 1 and 8 receptors, but enhanced by the expression of a chimeric cell-membrane-tethered frizzled 8 CRD. Moreover, soluble, partially purified recombinant FZC18_CRD inhibited Wnt3a-induced β-catenin activation. Taken together, the data indicate that collagen XVIII-derived frizzled CRD shifts Wnt sensitivity of normal cells to a lower pitch and controls their growth.

  7. Wnt activation affects proliferation, invasiveness and radiosensitivity in medulloblastoma.

    Science.gov (United States)

    Salaroli, Roberta; Ronchi, Alice; Buttarelli, Francesca Romana; Cortesi, Filippo; Marchese, Valeria; Della Bella, Elena; Renna, Cristiano; Baldi, Caterina; Giangaspero, Felice; Cenacchi, Giovanna

    2015-01-01

    Medulloblastomas (MBs) associated with the Wnt activation represent a subgroup with a favorable prognosis, but it remains unclear whether Wnt activation confers a less aggressive phenotype and/or enhances radiosensitivity. To investigate this issue, we evaluated the biological behavior of an MB cell line, UW228-1, stably transfected with human β-catenin cDNA encoding a nondegradable form of β-catenin (UW-B) in standard culture conditions and after radiation treatment. We evaluated the expression, transcriptional activity, and localization of β-catenin in the stably transfected cells using immunofluorescence and WB. We performed morphological analysis using light and electron microscopy. We then analyzed changes in the invasiveness, growth, and mortality in standard culture conditions and after radiation. We demonstrated that (A) Wnt activation inhibited 97 % of the invasion capability of the cells, (B) the growth of the UW-B cells was statistically significantly lower than that of all the other control cells (p < 0.01), (C) the mortality of irradiated UW-B cells was statistically significantly higher than that of the controls and their nonirradiated counterparts (p < 0.05), and (D) morphological features of neuronal differentiation were observed in the Wnt-activated cells. In tissue samples, the Ki-67 labeling index (LI) was lower in β-catenin-positive samples compared to non-β-catenin positive ones. The Ki-67 LI median (LI = 40) of the nuclear β-catenin-positive tumor samples was lower than that of non-nuclear β-catenin-positive samples (LI = 50), but the difference was not statistically significant. Overall, our data suggest that activation of the Wnt pathway reduces the proliferation and invasion of MBs and increases the tumor's radiosensitivity.

  8. Bone Morphogenetic Protein 15 (BMP15) Acts as a BMP and Wnt Inhibitor during Early Embryogenesis*

    Science.gov (United States)

    Di Pasquale, Elisa; Brivanlou, Ali H.

    2009-01-01

    Bone morphogenetic protein 15 (BMP15) belongs to an unusual subgroup of the transforming growth factor β (TGFβ) superfamily of signaling ligands as it lacks a key cysteine residue in the mature region required for proper intermolecular dimerization. Naturally occurring BMP15 mutation leads to early ovarian failure in humans, and BMP15 has been shown to activate the Smad1/5/8 pathway in that context. Despite its important role in germ cell specification, the embryological function of BMP15 remains unknown. Surprisingly, we find that during early Xenopus embryogenesis BMP15 acts solely as an inhibitor of the Smad1/5/8 pathway and the Wnt pathway. BMP15 gain-of-function leads to embryos with secondary ectopic heads and to direct neural induction in intact explants. BMP15 inhibits BMP4-mediated epidermal induction in dissociated explants. BMP15 strongly inhibits BRE response induced by BMP4 and blocks phosphorylation and activation of Smad1/5/8 MH2-domain. Mechanistically, BMP15 protein specifically interacts with BMP4 protein, suggesting inhibition upstream of receptor binding. Loss-of-function experiments using morpholinos or a naturally occurring human BMP15 dominant-negative mutant (BMP15-Y235C) leads to embryos lacking head. BMP15-Y235C also eliminates the inhibitory activity of BMP15 on BRE (BMP-responsive element). Finally, we show that BMP15 inhibits the canonical branch of the Wnt pathway, upstream of β-catenin. We, thus, demonstrate that BMP15 is necessary and sufficient for the specification of dorso-anterior structures and highlight novel mechanisms of BMP15 function that strongly suggest a reinterpretation of its function in ovaries specially for ovarian failure. PMID:19553676

  9. Therapeutic effect of a novel Wnt pathway inhibitor on cardiac regeneration after myocardial infarction.

    Science.gov (United States)

    Yang, Dezhong; Fu, Wenbin; Li, Liangpeng; Xia, Xuewei; Liao, Qiao; Yue, Rongchuan; Chen, Hongmei; Chen, Xiongwen; An, Songzhu; Zeng, Chunyu; Wang, Wei Eric

    2017-12-15

    After myocardial infarction (MI), the heart is difficult to repair because of great loss of cardiomyoctyes and lack of cardiac regeneration. Novel drug candidates that aim at reducing pathological remodeling and stimulating cardiac regeneration are highly desirable. In the present study, we identified if and how a novel porcupine inhibitor CGX1321 influenced MI and cardiac regeneration. Permanent ligation of left anterior descending (LAD) coronary artery was performed in mice to induce MI injury. Cardiac function was measured by echocardiography, infarct size was examined by TTC staining. Fibrosis was evaluated with Masson's trichrome staining and vimentin staining. As a result, CGX1321 administration blocked the secretion of Wnt proteins, and inhibited both canonical and non-canonical Wnt signaling pathways. CGX1321 improved cardiac function, reduced myocardial infarct size, and fibrosis of post-MI hearts. CGX1321 significantly increased newly formed cardiomyocytes in infarct border zone of post-MI hearts, evidenced by the increased EdU + cardiomyocytes. Meanwhile, CGX1321 increased Ki67 + and phosphohistone H3 (PH3 + ) cardiomyocytes in culture, indicating enhanced cardiomyocyte proliferation. The mRNA microarray showed that CGX1321 up-regulated cell cycle regulating genes such as Ccnb1 and Ccne1 CGX1321 did not alter YAP protein phosphorylation and nuclear translocation in cardiomyocytes. In conclusion, porcupine inhibitor CGX1321 reduces MI injury by limiting fibrosis and promoting regeneration. It promotes cardiomyocyte proliferation by stimulating cell cycle regulating genes with a Hippo/YAP-independent pathway. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  10. Identification of crucial microRNAs and genes in hypoxia-induced human lung adenocarcinoma cells

    Directory of Open Access Journals (Sweden)

    Geng Y

    2016-07-01

    Full Text Available Ying Geng,1,* Lili Deng,2,* Dongju Su,1 Jinling Xiao,1 Dongjie Ge,3 Yongxia Bao,1 Hui Jing4 1Department of Respiratory, 2Department of Oncology, The Second Affiliated Hospital of Harbin Medical University, 3Department of Respiratory, The First Hospital of Harbin, 4Department of Emergency, The Second Affiliated Hospital of Harbin Medical University Harbin, Heilongjiang, People’s Republic of China *These authors contributed equally to this work Background: Variations of microRNA (miRNA expression profile in hypoxic lung cancer cells have not been studied so far. Therefore, using miRNA microarray technology, this study aimed to study the miRNA expression profile and investigate the potential crucial miRNAs and their target genes in hypoxia-induced human lung adenocarcinoma cells.Materials and methods: Based on miRNA microarray, miRNA expression profiling of hypoxia-induced lung adenocarcinoma A549 cells was obtained. After identification of differentially expressed miRNAs (DE-miRNAs in hypoxic cells, target genes of DE-miRNAs were predicted, and functional enrichment analysis of targets was conducted. Furthermore, the expression levels of DE-miRNAs and their target genes were validated by real-time quantitative polymerase chain reaction. In addition, using miRNA mimics, the effect of overexpressed DE-miRNAs on A549 cell behaviors (cell proliferation, cell cycle, and apoptosis was evaluated.Results: In total, 14 DE-miRNAs (nine upregulated miRNAs and five downregulated miRNAs were identified in hypoxic cells, compared with normoxic cells. Target genes of both upregulated and downregulated miRNAs were enriched in the functions such as chromatin modification, and pathways such as Wnt signaling pathway and transforming growth factor (TGF-β signaling pathway. The expression levels of several miRNAs and their target genes were confirmed, including hsa-miR-301b/FOXF2, hsa-miR-148b-3p/WNT10B, hsa-miR-769-5p/(SMAD2, ARID1A, and hsa-miR-622. Among them

  11. WNT5A inhibits human dental papilla cell proliferation and migration

    International Nuclear Information System (INIS)

    Peng, L.; Ye, L.; Dong, G.; Ren, L.B.; Wang, C.L.; Xu, P.; Zhou, X.D.

    2009-01-01

    WNT proteins are a large family of cysteine-rich secreted molecules that are linked to both canonical and non-canonical signal pathways, and have been implicated in oncogenesis and tissue development. Canonical WNT proteins have been proven to play critical roles in tooth development, while little is known about the role of non-canonical WNT proteins such as WNT5A. In this study, WNT5A was localized to human dental papilla tissue and human dental papilla cells (HDPCs) cultured in vitro, using immunochemistry and RT-PCR. Recombinant adenovirus encoding full-length Wnt5a cDNA was constructed to investigate the biological role of WNT5A on HDPCs. The BrdU incorporation assay, the MTT assay and flow cytometric analysis showed that over-expression of Wnt5a strongly inhibited the proliferation of HDPCs in vitro. Wound healing and transwell migration assays indicated that over-expression of WNT5A reduced migration of HDPCs. In conclusion, our results showed that WNT5A negatively regulates both proliferation and migration of HDPCs, suggesting its important role in odontogenesis via controlling the HDPCs.

  12. Canonical Wnt signaling transiently stimulates proliferation and enhances neurogenesis in neonatal neural progenitor cultures

    International Nuclear Information System (INIS)

    Hirsch, Cordula; Campano, Louise M.; Woehrle, Simon; Hecht, Andreas

    2007-01-01

    Canonical Wnt signaling triggers the formation of heterodimeric transcription factor complexes consisting of β-catenin and T cell factors, and thereby controls the execution of specific genetic programs. During the expansion and neurogenic phases of embryonic neural development canonical Wnt signaling initially controls proliferation of neural progenitor cells, and later neuronal differentiation. Whether Wnt growth factors affect neural progenitor cells postnatally is not known. Therefore, we have analyzed the impact of Wnt signaling on neural progenitors isolated from cerebral cortices of newborn mice. Expression profiling of pathway components revealed that these cells are fully equipped to respond to Wnt signals. However, Wnt pathway activation affected only a subset of neonatal progenitors and elicited a limited increase in proliferation and neuronal differentiation in distinct subsets of cells. Moreover, Wnt pathway activation only transiently stimulated S-phase entry but did not support long-term proliferation of progenitor cultures. The dampened nature of the Wnt response correlates with the predominant expression of inhibitory pathway components and the rapid actuation of negative feedback mechanisms. Interestingly, in differentiating cell cultures activation of canonical Wnt signaling reduced Hes1 and Hes5 expression suggesting that during postnatal neural development, Wnt/β-catenin signaling enhances neurogenesis from progenitor cells by interfering with Notch pathway activity

  13. Involvement of wnt signaling pathways in the metamorphosis of the bryozoan bugula neritina

    KAUST Repository

    Wong, Yue Him

    2012-03-20

    In this study, we analyzed the metamorphosis of the marine bryozoan Bugula neritina. We observed the morphogenesis of the ancestrula. We defined three distinct pre-ancestrula stages based on the anatomy of the developing polypide and the overall morphology of pre-ancestrula. We then used an annotation based enrichment analysis tool to analyze the B. neritina transcriptome and identified over-representation of genes related to Wnt signaling pathways, suggesting its involvement in metamorphosis. Finally, we studied the temporal-spatial gene expression studies of several Wnt pathway genes. We found that one of the Wnt ligand, BnWnt10, was expressed spatially opposite to the Wnt antagonist BnsFRP within the blastemas, which is the presumptive polypide. Down-stream components of the canonical Wnt signaling pathway were exclusively expressed in the blastemas. Bn?catenin and BnFz5/8 were exclusively expressed in the blastemas throughout the metamorphosis. Based on the genes expression patterns, we propose that BnWnt10 and BnsFRP may relate to the patterning of the polypide, in which the two genes served as positional signals and contributed to the polarization of the blastemas. Another Wnt ligand, BnWnt6, was expressed in the apical part of the pre-ancestrula epidermis. Overall, our findings suggest that the Wnt signaling pathway may be important to the pattern formation of polypide and the development of epidermis. © 2012 Wong et al.

  14. Involvement of wnt signaling pathways in the metamorphosis of the bryozoan bugula neritina

    KAUST Repository

    Wong, Yue Him; Wang, Hao; Ravasi, Timothy; Qian, Pei-Yuan

    2012-01-01

    In this study, we analyzed the metamorphosis of the marine bryozoan Bugula neritina. We observed the morphogenesis of the ancestrula. We defined three distinct pre-ancestrula stages based on the anatomy of the developing polypide and the overall morphology of pre-ancestrula. We then used an annotation based enrichment analysis tool to analyze the B. neritina transcriptome and identified over-representation of genes related to Wnt signaling pathways, suggesting its involvement in metamorphosis. Finally, we studied the temporal-spatial gene expression studies of several Wnt pathway genes. We found that one of the Wnt ligand, BnWnt10, was expressed spatially opposite to the Wnt antagonist BnsFRP within the blastemas, which is the presumptive polypide. Down-stream components of the canonical Wnt signaling pathway were exclusively expressed in the blastemas. Bn?catenin and BnFz5/8 were exclusively expressed in the blastemas throughout the metamorphosis. Based on the genes expression patterns, we propose that BnWnt10 and BnsFRP may relate to the patterning of the polypide, in which the two genes served as positional signals and contributed to the polarization of the blastemas. Another Wnt ligand, BnWnt6, was expressed in the apical part of the pre-ancestrula epidermis. Overall, our findings suggest that the Wnt signaling pathway may be important to the pattern formation of polypide and the development of epidermis. © 2012 Wong et al.

  15. Down-regulation of Wnt10a affects odontogenesis and proliferation in mesenchymal cells

    International Nuclear Information System (INIS)

    Liu, Yang; Han, Dong; Wang, Lei; Feng, Hailan

    2013-01-01

    Highlights: •Down-regulation of Wnt10a in dental mesenchymal cells impairs odontogenesis of reassociated tooth germs. •Dspp is down- and up-regulated after Wnt10a-knockdown and overexpression in dental mesenchymal cells. •Down-regulation of Wnt10a inhibits proliferation of dental mesenchymal cells. -- Abstract: The WNT10a mutation has been found in patients with abnormal odontogenesis. In mice, Wnt10a expression is found in the tooth germ, but its role has not yet been elucidated. We aimed to investigate the role of Wnt10a in odontogenesis. Mesenchymal cells of the first mandibular molar germ at the bell stage were isolated, transfected with Wnt10a SiRNA or plasmid, and reassociated with epithelial part of the molar germ. Scrambled SiRNA or empty vector was used in the control group. The reassociated tooth germs were transplanted into mice subrenal capsules. After gene modification, dental mesenchymal cells cultured in vitro were checked for cell proliferation and the expression of Dspp was examined. All 12 reassociated tooth germs in the control group resumed odontogenesis, while only 5 of 12 in the Wnt10a knockdown group developed into teeth. After Wnt10a knockdown, the mesenchymal cells cultured in vitro presented repressed proliferation. Wnt10a knockdown and overexpression led to both down- and up-regulation of Dspp. We conclude that the down-regulation of Wnt10a impairs odontogensis and cell proliferation, and that Wnt10a regulates Dspp expression in mesenchymal cells. These findings help to elucidate the mechanism of abnormal tooth development in patients with the WNT10A mutation

  16. WNT5A inhibits metastasis and alters splicing of Cd44 in breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Wen Jiang

    Full Text Available Wnt5a is a non-canonical signaling Wnt. Low expression of WNT5A is correlated with poor prognosis in breast cancer patients. The highly invasive breast cancer cell lines, MDA-MB-231 and 4T1, express very low levels of WNT5A. To determine if enhanced expression of WNT5A would affect metastatic behavior, we generated WNT5A expressing cells from the 4T1 and MDA-MB-231 parental cell lines. WNT5A expressing cells demonstrated cobblestone morphology and reduced in vitro migration relative to controls. Cell growth was not altered. Metastasis to the lung via tail vein injection was reduced in the 4T1-WNT5A expressing cells relative to 4T1-vector controls. To determine the mechanism of WNT5A action on metastasis, we performed microarray and whole-transcriptome sequence analysis (RNA-seq to compare gene expression in 4T1-WNT5A and 4T1-vector cells. Analysis indicated highly significant alterations in expression of genes associated with cellular movement. Down-regulation of a subset of these genes, Mmp13, Nos2, Il1a, Cxcl2, and Lamb3, in WNT5A expressing cells was verified by semi-quantitative RT-PCR. Significant differences in transcript splicing were also detected in cell movement associated genes including Cd44. Cd44 is an adhesion molecule with a complex genome structure. Variable exon usage is associated with metastatic phenotype. Alternative spicing of Cd44 in WNT5A expressing cells was confirmed using RT-PCR. We conclude that WNT5A inhibits metastasis through down-regulation of multiple cell movement pathways by regulating transcript levels and splicing of key genes like Cd44.

  17. The dual role of autophagy under hypoxia-involvement of interaction between autophagy and apoptosis.

    Science.gov (United States)

    Li, Mengmeng; Tan, Jin; Miao, Yuyang; Lei, Ping; Zhang, Qiang

    2015-06-01

    Hypoxia is one of severe cellular stress and it is well known to be associated with a worse outcome since a lack of oxygen accelerates the induction of apoptosis. Autophagy, an important and evolutionarily conserved mechanism for maintaining cellular homeostasis, is closely related to the apoptosis caused by hypoxia. Generally autophagy blocks the induction of apoptosis and inhibits the activation of apoptosis-associated caspase which could reduce cellular injury. However, in special cases, autophagy or autophagy-relevant proteins may help to induce apoptosis, which could aggravate cell damage under hypoxia condition. In addition, the activation of apoptosis-related proteins-caspase can also degrade autophagy-related proteins, such as Atg3, Atg4, Beclin1 protein, inhibiting autophagy. Although the relationship between autophagy and apoptosis has been known for rather complex for more than a decade, the underlying regulatory mechanisms have not been clearly understood. This short review discusses and summarizes the dual role of autophagy and the interaction and molecular regulatory mechanisms between autophagy and apoptosis under hypoxia.

  18. Saururus cernuus lignans-Potent small molecule inhibitors of hypoxia-inducible factor-1

    International Nuclear Information System (INIS)

    Hossain, Chowdhury Faiz; Kim, Yong-Pil; Baerson, Scott R.; Zhang Lei; Bruick, Richard K.; Mohammed, Kaleem A.; Agarwal, Ameeta K.; Nagle, Dale G.; Zhou Yudong

    2005-01-01

    Hypoxia-inducible factor-1 (HIF-1) represents an important tumor-selective therapeutic target for solid tumors. In search of novel small molecule HIF-1 inhibitors, 5400 natural product-rich extracts from plants, marine organisms, and microbes were examined for HIF-1 inhibitory activities using a cell-based reporter assay. Bioassay-guided fractionation and isolation, followed by structure elucidation, yielded three potent natural product-derived HIF-1 inhibitors and two structurally related inactive compounds. In a T47D cell-based reporter assay, manassantin B 1 , manassantin A, and 4-O-methylsaucerneol inhibited hypoxia-induced HIF-1 activation with IC 50 values of 3, 3, and 20 nM, respectively. All three compounds are relatively hypoxia-specific inhibitors of HIF-1 activation, in comparison to other stimuli. The hypoxic induction of HIF-1 target genes CDKN1A, VEGF, and GLUT-1 were also inhibited. These compounds inhibit HIF-1 by blocking hypoxia-induced nuclear HIF-1α protein accumulation without affecting HIF-1α mRNA levels. In addition, preliminary structure-activity studies suggest specific structural requirements for this class of HIF-1 inhibitors

  19. Inhibition of endocytosis blocks Wnt signalling to beta-catenin by promoting dishevelled degradation

    Czech Academy of Sciences Publication Activity Database

    Bryja, Vítězslav; Čajánek, L.; Grahn, A.; Schulte, G.

    2007-01-01

    Roč. 190, č. 1 (2007), s. 53-596 ISSN 0001-6772 Institutional research plan: CEZ:AV0Z50040507 Keywords : beta-catenin * clathrin-mediated endocytosis * desensitization Subject RIV: BO - Biophysics Impact factor: 2.554, year: 2007

  20. [Electrophysiological study on rat conduit pulmonary artery smooth muscle cells under normoxia and acute hypoxia].

    Science.gov (United States)

    Hu, Ying; Zou, Fei; Cai, Chun-Qing; Wu, Hang-Yu; Yun, Hai-Xia; Chen, Yun-Tian; Jin, Guo-En; Ge, Ri-Li

    2006-10-25

    The present study was designed to investigate the electrophysiological characteristics of rat conduit pulmonary artery smooth muscle cells (PASMCs) and the response to acute hypoxia. PASMCs of the 1st to 2nd order branches in the conduit pulmonary arteries were obtained by enzymatic isolation. The PASMCs were divided into acute hypoxia preconditioned group and normoxia group. Hypoxia solutions were achieved by bubbling with 5% CO2 plus 95% N2 for at least 30 min before cell perfusion. Potassium currents were compared between these two groups using whole-cell patch clamp technique. The total outward current of PASMCs was measured under normoxia condition when iBTX [specific blocking agent of large conductance Ca-activated K(+) (BK(Ca)) channel] and 4-AP [specific blocking agent of delayed rectifier K(+) (K(DR)) channel] were added consequently into bath solution. PASMCs were classified into three types according to their size, shape and electrophysiological characteristics. Type I cells are the smallest with spindle shape, smooth surface and discrete perinuclear bulge. Type II cells show the biggest size with banana-like appearance. Type III cells have the similar size with type I, and present intermediary shape between type I and type II. iBTX had little effect on the total outward current in type I cells, while 4-AP almost completely blocked it. Most of the total outward current in type II cells was inhibited by iBTX, and the remaining was sensitive to 4-AP. In type III cells, the total outward current was sensitive to both iBTX and 4-AP. Acute hypoxia reduced the current in all three types of cells: (1614.8+/-62.5) pA to (892.4+/-33.6) pA for type I cells (Ppotassium current and improves the E(m) in PASMCs. These effects may be involved in the modulation of constriction/relaxation of conduit artery under acute hypoxia. Different distribution of K(DR) and BK(Ca) channels in these three types of PASMCs might account for their different constriction

  1. Genomic response to Wnt signalling is highly context-dependent - Evidence from DNA microarray and chromatin immunoprecipitation screens of Wnt/TCF targets

    International Nuclear Information System (INIS)

    Railo, Antti; Pajunen, Antti; Itaeranta, Petri; Naillat, Florence; Vuoristo, Jussi; Kilpelaeinen, Pekka; Vainio, Seppo

    2009-01-01

    Wnt proteins are important regulators of embryonic development, and dysregulated Wnt signalling is involved in the oncogenesis of several human cancers. Our knowledge of the downstream target genes is limited, however. We used a chromatin immunoprecipitation-based assay to isolate and characterize the actual gene segments through which Wnt-activatable transcription factors, TCFs, regulate transcription and an Affymetrix microarray analysis to study the global transcriptional response to the Wnt3a ligand. The anti-β-catenin immunoprecipitation of DNA-protein complexes from mouse NIH3T3 fibroblasts expressing a fusion protein of β-catenin and TCF7 resulted in the identification of 92 genes as putative TCF targets. GeneChip assays of gene expression performed on NIH3T3 cells and the rat pheochromocytoma cell line PC12 revealed 355 genes in NIH3T3 and 129 genes in the PC12 cells with marked changes in expression after Wnt3a stimulus. Only 2 Wnt-regulated genes were shared by both cell lines. Surprisingly, Disabled-2 was the only gene identified by the chromatin immunoprecipitation approach that displayed a marked change in expression in the GeneChip assay. Taken together, our approaches give an insight into the complex context-dependent nature of Wnt pathway transcriptional responses and identify Disabled-2 as a potential new direct target for Wnt signalling.

  2. Tumor Hypoxia: Causative Mechanisms, Microregional Heterogeneities, and the Role of Tissue-Based Hypoxia Markers.

    Science.gov (United States)

    Vaupel, Peter; Mayer, Arnulf

    Tumor hypoxia is a hallmark of solid malignant tumor growth, profoundly influences malignant progression and contributes to the development of therapeutic resistance. Pathogenesis of tumor hypoxia is multifactorial, with contributions from both acute and chronic factors. Spatial distribution of hypoxia within tumors is markedly heterogeneous and often changes over time, e.g., during a course of radiotherapy. Substantial changes in the oxygenation status can occur within the distance of a few cell layers, explaining the inability of currently used molecular imaging techniques to adequately assess this crucial trait. Due to the possible importance of tumor hypoxia for clinical decision-making, there is a great demand for molecular tools which may provide the necessary resolution down to the single cell level. Exogenous and endogenous markers of tumor hypoxia have been investigated for this purpose. Their potential use may be greatly enhanced by multiparametric in situ methods in experimental and human tumor tissue.

  3. Hypoxia and hypoxia inducible factor-1α are required for normal endometrial repair during menstruation.

    Science.gov (United States)

    Maybin, Jacqueline A; Murray, Alison A; Saunders, Philippa T K; Hirani, Nikhil; Carmeliet, Peter; Critchley, Hilary O D

    2018-01-23

    Heavy menstrual bleeding (HMB) is common and debilitating, and often requires surgery due to hormonal side effects from medical therapies. Here we show that transient, physiological hypoxia occurs in the menstrual endometrium to stabilise hypoxia inducible factor 1 (HIF-1) and drive repair of the denuded surface. We report that women with HMB have decreased endometrial HIF-1α during menstruation and prolonged menstrual bleeding. In a mouse model of simulated menses, physiological endometrial hypoxia occurs during bleeding. Maintenance of mice under hyperoxia during menses decreases HIF-1α induction and delays endometrial repair. The same effects are observed upon genetic or pharmacological reduction of endometrial HIF-1α. Conversely, artificial induction of hypoxia by pharmacological stabilisation of HIF-1α rescues the delayed endometrial repair in hypoxia-deficient mice. These data reveal a role for HIF-1 in the endometrium and suggest its pharmacological stabilisation during menses offers an effective, non-hormonal treatment for women with HMB.

  4. Wnt5 is required for notochord cell intercalation in the ascidian Halocynthia roretzi.

    Science.gov (United States)

    Niwano, Tomoko; Takatori, Naohito; Kumano, Gaku; Nishida, Hiroki

    2009-08-25

    In the embryos of various animals, the body elongates after gastrulation by morphogenetic movements involving convergent extension. The Wnt/PCP (planar cell polarity) pathway plays roles in this process, particularly mediolateral polarization and intercalation of the embryonic cells. In ascidians, several factors in this pathway, including Wnt5, have been identified and found to be involved in the intercalation process of notochord cells. In the present study, the role of the Wnt5 genes, Hr-Wnt5alpha (Halocynthia roretzi Wnt5alpha) and Hr-Wnt5beta, in convergent extension was investigated in the ascidian H. roretzi by injecting antisense oligonucleotides and mRNAs into single precursor blastomeres of various tissues, including notochord, at the 64-cell stage. Hr-Wnt5alpha is expressed in developing notochord and was essential for notochord morphogenesis. Precise quantitative control of its expression level was crucial for proper cell intercalation. Overexpression of Wnt5 proteins in notochord and other tissues that surround the notochord indicated that Wnt5alpha plays a role within the notochord, and is unlikely to be the source of polarizing cues arising outside the notochord. Detailed mosaic analysis of the behaviour of individual notochord cells overexpressing Wnt5alpha indicated that a Wnt5alpha-manipulated cell does not affect the behaviour of neighbouring notochord cells, suggesting that Wnt5alpha works in a cell-autonomous manner. This is further supported by comparison of the results of Wnt5alpha and Dsh (Dishevelled) knockdown experiments. In addition, our results suggest that the Wnt/PCP pathway is also involved in mediolateral intercalation of cells of the ventral row of the nerve cord (floor plate) and the endodermal strand. The present study highlights the role of the Wnt5alpha signal in notochord convergent extension movements in ascidian embryos. Our results raise the novel possibility that Wnt5alpha functions in a cell-autonomous manner in

  5. Diphtheria Toxin-Induced Cell Death Triggers Wnt-Dependent Hair Cell Regeneration in Neonatal Mice.

    Science.gov (United States)

    Hu, Lingxiang; Lu, Jingrong; Chiang, Hao; Wu, Hao; Edge, Albert S B; Shi, Fuxin

    2016-09-07

    Cochlear hair cells (HCs), the sensory cells that respond to sound, do not regenerate after damage in adult mammals, and their loss is a major cause of deafness. Here we show that HC regeneration in newborn mouse ears occurred spontaneously when the original cells were ablated by treatment with diphtheria toxin (DT) in ears that had been engineered to overexpress the DT receptor, but was not detectable when HCs were ablated in vivo by the aminoglycoside antibiotic neomycin. A variety of Wnts (Wnt1, Wnt2, Wnt2b, Wnt4, Wnt5a, Wnt7b, Wnt9a, Wnt9b, and Wnt11) and Wnt pathway component Krm2 were upregulated after DT damage. Nuclear β-catenin was upregulated in HCs and supporting cells of the DT-damaged cochlea. Pharmacological inhibition of Wnt decreased spontaneous regeneration, confirming a role of Wnt signaling in HC regeneration. Inhibition of Notch signaling further potentiated supporting cell proliferation and HC differentiation that occurred spontaneously. The absence of new HCs in the neomycin ears was correlated to less robust Wnt pathway activation, but the ears subjected to neomycin treatment nonetheless showed increased cell division and HC differentiation after subsequent forced upregulation of β-catenin. These studies suggest, first, that Wnt signaling plays a key role in regeneration, and, second, that the outcome of a regenerative response to damage in the newborn cochlea is determined by reaching a threshold level of Wnt signaling rather than its complete absence or presence. Sensory HCs of the inner ear do not regenerate in the adult, and their loss is a major cause of deafness. We found that HCs regenerated spontaneously in the newborn mouse after diphtheria toxin (DT)-induced, but not neomycin-induced, HC death. Regeneration depended on activation of Wnt signaling, and regeneration in DT-treated ears correlated to a higher level of Wnt activation than occurred in nonregenerating neomycin-treated ears. This is significant because insufficient

  6. Hypoxia training: symptom replication in experienced military aircrew.

    Science.gov (United States)

    Johnston, Ben J; Iremonger, Gareth S; Hunt, Sheena; Beattie, Elizabeth

    2012-10-01

    Military aircrew are trained to recognize the signs and symptoms of hypoxia in a safe environment using a variety of methods to simulate altitude. In order to investigate the effectiveness of hypoxia training, this study compared the recall of hypoxia symptoms in military aircrew between two consecutive hypobaric chamber hypoxia training sessions conducted, on average, 4.5 yr apart. Previously trained subjects completed a questionnaire immediately before and after they underwent refresher hypoxia training and recorded the occurrence, order, and severity of symptoms experienced. Responses from refresher training were compared with their recall of symptoms experienced during previous training. There was no difference in the recall of most hypoxia symptoms between training sessions. Slurred speech was recalled more frequently from previous training compared to refresher training (14 vs. 4 subjects), whereas hot/cold flushes were recalled less frequently from previous training compared to refresher training (5 vs. 17 subjects). There was a statistically significant difference in overall hypoxia score (10.3 vs. 8.3), suggesting that from memory subjects may underestimate the level of hypoxia experienced in previous training. A high level of similarity between the recall of previously experienced hypoxia symptoms and recent experience supports the effectiveness of hypoxia training. These results replicate the finding of a 'hypoxia signature' reported by a previous study. Small differences in the recall of some symptoms and in overall hypoxia score highlight the importance of drawing attention to the more subtle symptoms of early hypoxia, and of using training techniques which optimize aircrew recall.

  7. A Glimpse of the Pathogenetic Mechanisms of Wnt/β-Catenin Signaling in Diabetic Nephropathy

    Directory of Open Access Journals (Sweden)

    Li Xiao

    2013-01-01

    Full Text Available The Wnt family of proteins belongs to a group of secreted lipid-modified glycoproteins with highly conserved cysteine residues. Prior results indicate that Wnt/β-catenin signaling plays a prominent role in cell differentiation, adhesion, survival, and apoptosis and is involved in organ development, tumorigenesis, and tissue fibrosis, among other functions. Accumulating evidence has suggested that Wnt/β-catenin exhibits a pivotal function in the progression of diabetic nephropathy (DN. In this review, we focused on discussing the dual role of Wnt/β-catenin in apoptosis and epithelial mesenchymal transition (EMT formation of mesangial cells. Moreover, we also elucidated the effect of Wnt/β-catenin in podocyte dysfunction, tubular EMT formation, and renal fibrosis under DN conditions. In addition, the molecular mechanisms involved in this process are introduced. This information provides a novel molecular target of Wnt/β-catenin for the protection of kidney damage and in delay of the progression of DN.

  8. Wnt and lithium: a common destiny in the therapy of nervous system pathologies?

    Science.gov (United States)

    Meffre, Delphine; Grenier, Julien; Bernard, Sophie; Courtin, Françoise; Dudev, Todor; Shackleford, Ghjuvan'Ghjacumu; Jafarian-Tehrani, Mehrnaz; Massaad, Charbel

    2014-04-01

    Wnt signaling is required for neurogenesis, the fate of neural progenitors, the formation of neuronal circuits during development, neuron positioning and polarization, axon and dendrite development and finally for synaptogenesis. This signaling pathway is also implicated in the generation and differentiation of glial cells. In this review, we describe the mechanisms of action of Wnt signaling pathways and their implication in the development and correct functioning of the nervous system. We also illustrate how a dysregulated Wnt pathway could lead to psychiatric, neurodegenerative and demyelinating pathologies. Lithium, used for the treatment of bipolar disease, inhibits GSK3β, a central enzyme of the Wnt/β-catenin pathway. Thus, lithium could, to some extent, mimic Wnt pathway. We highlight the possible dialogue between lithium therapy and modulation of Wnt pathway in the treatment of the diseases of the nervous system.

  9. Lens regeneration from the cornea requires suppression of Wnt/β-catenin signaling.

    Science.gov (United States)

    Hamilton, Paul W; Sun, Yu; Henry, Jonathan J

    2016-04-01

    The frog, Xenopus laevis, possesses a high capacity to regenerate various larval tissues, including the lens, which is capable of complete regeneration from the cornea epithelium. However, the molecular signaling mechanisms of cornea-lens regeneration are not fully understood. Previous work has implicated the involvement of the Wnt signaling pathway, but molecular studies have been very limited. Iris-derived lens regeneration in the newt (Wolffian lens regeneration) has shown a necessity for active Wnt signaling in order to regenerate a new lens. Here we provide evidence that the Wnt signaling pathway plays a different role in the context of cornea-lens regeneration in Xenopus. We examined the expression of frizzled receptors and wnt ligands in the frog cornea epithelium. Numerous frizzled receptors (fzd1, fzd2, fzd3, fzd4, fzd6, fzd7, fzd8, and fzd10) and wnt ligands (wnt2b.a, wnt3a, wnt4, wnt5a, wnt5b, wnt6, wnt7b, wnt10a, wnt11, and wnt11b) are expressed in the cornea epithelium, demonstrating that this tissue is transcribing many of the ligands and receptors of the Wnt signaling pathway. When compared to flank epithelium, which is lens regeneration incompetent, only wnt11 and wnt11b are different (present only in the cornea epithelium), identifying them as potential regulators of cornea-lens regeneration. To detect changes in canonical Wnt/β-catenin signaling occurring within the cornea epithelium, axin2 expression was measured over the course of regeneration. axin2 is a well-established reporter of active Wnt/β-catenin signaling, and its expression shows a significant decrease at 24 h post-lentectomy. This decrease recovers to normal endogenous levels by 48 h. To test whether this signaling decrease was necessary for lens regeneration to occur, regenerating eyes were treated with either 6-bromoindirubin-3'-oxime (BIO) or 1-azakenpaullone - both activators of Wnt signaling - resulting in a significant reduction in the percentage of cases with successful

  10. Effects of Wnt3a on proliferation and differentiation of human epidermal stem cells

    International Nuclear Information System (INIS)

    Jia Liwei; Zhou Jiaxi; Peng Sha; Li Juxue; Cao Yujing; Duan Enkui

    2008-01-01

    Epidermal stem cells maintain development and homeostasis of mammalian epidermis throughout life. However, the molecular mechanisms involved in the proliferation and differentiation of epidermal stem cells are far from clear. In this study, we investigated the effects of Wnt3a and Wnt/β-catenin signaling on proliferation and differentiation of human fetal epidermal stem cells. We found both Wnt3a and active β-catenin, two key members of the Wnt/β-catenin signaling, were expressed in human fetal epidermis and epidermal stem cells. In addition, Wnt3a protein can promote proliferation and inhibit differentiation of epidermal stem cells in vitro culture. Our results suggest that Wnt/β-catenin signaling plays important roles in human fetal skin development and homeostasis, which also provide new insights on the molecular mechanisms of oncogenesis in human epidermis

  11. Noncanonical Wnt signaling promotes osteoclast differentiation and is facilitated by the human immunodeficiency virus protease inhibitor ritonavir

    International Nuclear Information System (INIS)

    Santiago, Francisco; Oguma, Junya; Brown, Anthony M.C.; Laurence, Jeffrey

    2012-01-01

    Highlights: ► First demonstration of direct role for noncanonical Wnt in osteoclast differentiation. ► Demonstration of Ryk as a Wnt5a/b receptor in inhibition of canonical Wnt signaling. ► Modulation of noncanonical Wnt signaling by a clinically important drug, ritonavir. ► Establishes a mechanism for an important clinical problem: HIV-associated bone loss. -- Abstract: Wnt proteins that signal via the canonical Wnt/β-catenin pathway directly regulate osteoblast differentiation. In contrast, most studies of Wnt-related effects on osteoclasts involve indirect changes. While investigating bone mineral density loss in the setting of human immunodeficiency virus (HIV) infection and its treatment with the protease inhibitor ritonavir (RTV), we observed that RTV decreased nuclear localization of β-catenin, critical to canonical Wnt signaling, in primary human and murine osteoclast precursors. This occurred in parallel with upregulation of Wnt5a and Wnt5b transcripts. These Wnts typically stimulate noncanonical Wnt signaling, and this can antagonize the canonical Wnt pathway in many cell types, dependent upon Wnt receptor usage. We now document RTV-mediated upregulation of Wnt5a/b protein in osteoclast precursors. Recombinant Wnt5b and retrovirus-mediated expression of Wnt5a enhanced osteoclast differentiation from human and murine monocytic precursors, processes facilitated by RTV. In contrast, canonical Wnt signaling mediated by Wnt3a suppressed osteoclastogenesis. Both RTV and Wnt5b inhibited canonical, β-catenin/T cell factor-based Wnt reporter activation in osteoclast precursors. RTV- and Wnt5-induced osteoclast differentiation were dependent upon the receptor-like tyrosine kinase Ryk, suggesting that Ryk may act as a Wnt5a/b receptor in this context. This is the first demonstration of a direct role for Wnt signaling pathways and Ryk in regulation of osteoclast differentiation, and its modulation by a clinically important drug, ritonavir. These studies

  12. Ultrasound guided supraclavicular block.

    LENUS (Irish Health Repository)

    Hanumanthaiah, Deepak

    2013-09-01

    Ultrasound guided regional anaesthesia is becoming increasingly popular. The supraclavicular block has been transformed by ultrasound guidance into a potentially safe superficial block. We reviewed the techniques of performing supraclavicular block with special focus on ultrasound guidance.

  13. Bone Mass and Strength are Significantly Improved in Mice Overexpressing Human WNT16 in Osteocytes.

    Science.gov (United States)

    Alam, Imranul; Reilly, Austin M; Alkhouli, Mohammed; Gerard-O'Riley, Rita L; Kasipathi, Charishma; Oakes, Dana K; Wright, Weston B; Acton, Dena; McQueen, Amie K; Patel, Bhavmik; Lim, Kyung-Eun; Robling, Alexander G; Econs, Michael J

    2017-04-01

    Recently, we demonstrated that osteoblast-specific overexpression of human WNT16 increased both cortical and trabecular bone mass and structure in mice. To further identify the cell-specific role of Wnt16 in bone homeostasis, we created transgenic (TG) mice overexpressing human WNT16 in osteocytes using Dmp1 promoter (Dmp1-hWNT16 TG) on C57BL/6 (B6) background. We analyzed bone phenotypes and serum bone biomarkers, performed gene expression analysis and measured dynamic bone histomorphometry in Dmp1-hWNT16 TG and wild-type (WT) mice. Compared to WT mice, Dmp1-hWNT16 TG mice exhibited significantly higher whole-body, spine and femoral aBMD, BMC and trabecular (BV/TV, Tb.N, and Tb.Th) and cortical (bone area and thickness) parameters in both male and female at 12 weeks of age. Femur stiffness and ultimate force were also significantly improved in the Dmp1-hWNT16 TG female mice, compared to sex-matched WT littermates. In addition, female Dmp1-hWNT16 TG mice displayed significantly higher MS/BS, MAR and BFR/BS compared to the WT mice. Gene expression analysis demonstrated significantly higher mRNA level of Alp in both male and female Dmp1-hWNT16 TG mice and significantly higher levels of Osteocalcin, Opg and Rankl in the male Dmp1-hWNT16 TG mice in bone tissue compared to sex-matched WT mice. These results indicate that WNT16 plays a critical role for acquisition of both cortical and trabecular bone mass and strength. Strategies designed to use WNT16 as a target for therapeutic interventions will be valuable to treat osteoporosis and other low bone mass conditions.

  14. Wnt5a Is Associated with Cigarette Smoke-Related Lung Carcinogenesis via Protein Kinase C

    OpenAIRE

    Whang, Young Mi; Jo, Ukhyun; Sung, Jae Sook; Ju, Hyun Jung; Kim, Hyun Kyung; Park, Kyong Hwa; Lee, Jong Won; Koh, In Song; Kim, Yeul Hong

    2013-01-01

    Wnt5a is overexpressed during the progression of human non-small cell lung cancer. However, the roles of Wnt5a during smoking-related lung carcinogenesis have not been clearly elucidated. We investigated the associations between Wnt5a and the early development of cigarette smoke related lung cancer using human bronchial epithelial (HBE) cells (NHBE, BEAS-2B, 1799, 1198 and 1170I) at different malignant stages established by exposure to cigarette smoke condensate (CSC). Abnormal up-regulation ...

  15. Wnt/β-catenin signaling: new (and old) players and new insights

    OpenAIRE

    Huang, He; He, Xi

    2008-01-01

    Wnt/β-catenin signaling has central roles in embryogenesis and human diseases including cancer. A central scheme of the Wnt pathway is to stabilize the transcription coactivator β-catenin by preventing its phosphorylation-dependent degradation. Significant progress has been made towards the understanding of this critical regulatory pathway, including the protein complex that promotes β-catenin phosphorylation-degradation, and the mechanism by which the extracellular Wnt ligand engages cell su...

  16. An in vitro fatty acylation assay reveals a mechanism for Wnt recognition by the acyltransferase Porcupine.

    Science.gov (United States)

    Asciolla, James J; Miele, Matthew M; Hendrickson, Ronald C; Resh, Marilyn D

    2017-08-18

    Wnt proteins are a family of secreted signaling proteins that play key roles in regulating cell proliferation in both embryonic and adult tissues. Production of active Wnt depends on attachment of palmitoleate, a monounsaturated fatty acid, to a conserved serine by the acyltransferase Porcupine (PORCN). Studies of PORCN activity relied on cell-based fatty acylation and signaling assays as no direct enzyme assay had yet been developed. Here, we present the first in vitro assay that accurately recapitulates PORCN-mediated fatty acylation of a Wnt substrate. The critical feature is the use of a double disulfide-bonded Wnt peptide that mimics the two-dimensional structure surrounding the Wnt acylation site. PORCN-mediated Wnt acylation was abolished when the Wnt peptide was treated with DTT, and did not occur with a linear (non-disulfide-bonded) peptide, or when the double disulfide-bonded Wnt peptide contained Ala substituted for the Ser acylation site. We exploited this in vitro Wnt acylation assay to provide direct evidence that the small molecule LGK974, which is in clinical trials for managing Wnt-driven tumors, is a bona fide PORCN inhibitor whose IC 50 for inhibition of Wnt fatty acylation in vitro closely matches that for inhibition of Wnt signaling. Side-by-side comparison of PORCN and Hedgehog acyltransferase (HHAT), two enzymes that attach 16-carbon fatty acids to secreted proteins, revealed that neither enzyme will accept the other's fatty acyl-CoA or peptide substrates. These findings illustrate the unique enzyme-substrate selectivity exhibited by members of the membrane-bound O -acyl transferase family. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Concurrent Transient Activation of Wnt/β-Catenin Pathway Prevents Radiation Damage to Salivary Glands

    International Nuclear Information System (INIS)

    Hai Bo; Yang Zhenhua; Shangguan Lei; Zhao Yanqiu; Boyer, Arthur; Liu, Fei

    2012-01-01

    Purpose: Many head and neck cancer survivors treated with radiotherapy suffer from permanent impairment of their salivary gland function, for which few effective prevention or treatment options are available. This study explored the potential of transient activation of Wnt/β-catenin signaling in preventing radiation damage to salivary glands in a preclinical model. Methods and Materials: Wnt reporter transgenic mice were exposed to 15 Gy single-dose radiation in the head and neck area to evaluate the effects of radiation on Wnt activity in salivary glands. Transient Wnt1 overexpression in basal epithelia was induced in inducible Wnt1 transgenic mice before together with, after, or without local radiation, and then saliva flow rate, histology, apoptosis, proliferation, stem cell activity, and mRNA expression were evaluated. Results: Radiation damage did not significantly affect activity of Wnt/β-catenin pathway as physical damage did. Transient expression of Wnt1 in basal epithelia significantly activated the Wnt/β-catenin pathway in submandibular glands of male mice but not in those of females. Concurrent transient activation of the Wnt pathway prevented chronic salivary gland dysfunction following radiation by suppressing apoptosis and preserving functional salivary stem/progenitor cells. In contrast, Wnt activation 3 days before or after irradiation did not show significant beneficial effects, mainly due to failure to inhibit acute apoptosis after radiation. Excessive Wnt activation before radiation failed to inhibit apoptosis, likely due to extensive induction of mitosis and up-regulation of proapoptosis gene PUMA while that after radiation might miss the critical treatment window. Conclusion: These results suggest that concurrent transient activation of the Wnt/β-catenin pathway could prevent radiation-induced salivary gland dysfunction.

  18. Concurrent Transient Activation of Wnt/{beta}-Catenin Pathway Prevents Radiation Damage to Salivary Glands

    Energy Technology Data Exchange (ETDEWEB)

    Hai Bo; Yang Zhenhua; Shangguan Lei; Zhao Yanqiu [Institute for Regenerative Medicine, Scott and White Hospital, Molecular and Cellular Medicine Department, Texas A and M Health Science Center, Temple, Texas (United States); Boyer, Arthur [Department of Radiology, Scott and White Hospital, Temple, Texas (United States); Liu, Fei, E-mail: fliu@medicine.tamhsc.edu [Institute for Regenerative Medicine, Scott and White Hospital, Molecular and Cellular Medicine Department, Texas A and M Health Science Center, Temple, Texas (United States)

    2012-05-01

    Purpose: Many head and neck cancer survivors treated with radiotherapy suffer from permanent impairment of their salivary gland function, for which few effective prevention or treatment options are available. This study explored the potential of transient activation of Wnt/{beta}-catenin signaling in preventing radiation damage to salivary glands in a preclinical model. Methods and Materials: Wnt reporter transgenic mice were exposed to 15 Gy single-dose radiation in the head and neck area to evaluate the effects of radiation on Wnt activity in salivary glands. Transient Wnt1 overexpression in basal epithelia was induced in inducible Wnt1 transgenic mice before together with, after, or without local radiation, and then saliva flow rate, histology, apoptosis, proliferation, stem cell activity, and mRNA expression were evaluated. Results: Radiation damage did not significantly affect activity of Wnt/{beta}-catenin pathway as physical damage did. Transient expression of Wnt1 in basal epithelia significantly activated the Wnt/{beta}-catenin pathway in submandibular glands of male mice but not in those of females. Concurrent transient activation of the Wnt pathway prevented chronic salivary gland dysfunction following radiation by suppressing apoptosis and preserving functional salivary stem/progenitor cells. In contrast, Wnt activation 3 days before or after irradiation did not show significant beneficial effects, mainly due to failure to inhibit acute apoptosis after radiation. Excessive Wnt activation before radiation failed to inhibit apoptosis, likely due to extensive induction of mitosis and up-regulation of proapoptosis gene PUMA while that after radiation might miss the critical treatment window. Conclusion: These results suggest that concurrent transient activation of the Wnt/{beta}-catenin pathway could prevent radiation-induced salivary gland dysfunction.

  19. WNT7b mediates macrophage-induced programmed cell death in patterning of the vasculature

    OpenAIRE

    Lobov, Ivan B.; Rao, Sujata; Carroll, Thomas J.; Vallance, Jefferson E.; Ito, Masataka; Ondr, Jennifer K.; Kurup, Savita; Glass, Donald A.; Patel, Millan S.; Shu, Weiguo; Morrisey, Edward E.; McMahon, Andrew P.; Karsenty, Gerard; Lang, Richard A.

    2005-01-01

    Macrophages have a critical role in inflammatory and immune responses through their ability to recognize and engulf apoptotic cells1. Here we show that macrophages initiate a cell-death programme in target cells by activating the canonical WNT pathway. We show in mice that macrophage WNT7b is a short-range paracrine signal required for WNT-pathway responses and programmed cell death in the vascular endothelial cells of the temporary hyaloid vessels of the developing eye. These findings indica...

  20. Blockade of Wnt-1 signaling leads to anti-tumor effects in hepatocellular carcinoma cells

    Directory of Open Access Journals (Sweden)

    Grepper Susan

    2009-09-01

    Full Text Available Abstract Background Hepatocellular carcinoma (HCC is an aggressive cancer, and is the third leading cause of cancer death worldwide. Standard therapy is ineffective partly because HCC is intrinsically resistant to conventional chemotherapy. Its poor prognosis and limited treatment options make it critical to develop novel and selective chemotherapeutic agents. Since the Wnt/β-catenin pathway is essential in HCC carcinogenesis, we studied the inhibition of Wnt-1-mediated signaling as a potential molecular target in HCC. Results We demonstrated that Wnt-1 is highly expressed in human hepatoma cell lines and a subgroup of human HCC tissues compared to paired adjacent non-tumor tissues. An anti-Wnt-1 antibody dose-dependently decreased viability and proliferation of Huh7 and Hep40 cells over-expressing Wnt-1 and harboring wild type β-catenin, but did not affect normal hepatocytes with undetectable Wnt-1 expression. Apoptosis was also observed in Huh7 and Hep40 cells after treatment with anti-Wnt-1 antibody. In these two cell lines, the anti-Wnt-1 antibody decreased β-catenin/Tcf4 transcriptional activities, which were associated with down-regulation of the endogenous β-catenin/Tcf4 target genes c-Myc, cyclin D1, and survivin. Intratumoral injection of anti-Wnt-1 antibody suppressed in vivo tumor growth in a Huh7 xenograft model, which was also associated with apoptosis and reduced c-Myc, cyclin D1, and survivin expressions. Conclusion Our results suggest that Wnt-1 is a survival factor for HCC cells, and that the blockade of Wnt-1-mediated signaling may offer a potential pathway-specific therapeutic strategy for the treatment of a subgroup of HCC that over-expresses Wnt-1.

  1. A deep investigation into the adipogenesis mechanism: Profile of microRNAs regulating adipogenesis by modulating the canonical Wnt/β-catenin signaling pathway

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    Li Jing

    2010-05-01

    Full Text Available Abstract Background MicroRNAs (miRNAs are a large class of tiny non-coding RNAs (~22-24 nt that regulate diverse biological processes at the posttranscriptional level by controlling mRNA stability or translation. As a molecular switch, the canonical Wnt/β-catenin signaling pathway should be suppressed during the adipogenesis; However, activation of this pathway leads to the inhibition of lipid depots formation. The aim of our studies was to identify miRNAs that might be involved in adipogenesis by modulating WNT signaling pathway. Here we established two types of cell model, activation and repression of WNT signaling, and investigated the expression profile of microRNAs using microarray assay. Results The high throughput microarray data revealed 18 miRNAs that might promote adipogenesis by repressing WNT signaling: miR-210, miR-148a, miR-194, miR-322 etc. Meanwhile, we also identified 29 miRNAs that might have negative effect on adipogenesis by activating WNT signaling: miR-344, miR-27 and miR-181 etc. The targets of these miRNAs were also analysed by bioinformatics. To validate the predicted targets and the potential functions of these identified miRNAs, the mimics of miR-210 were transfected into 3T3-L1 cells and enlarged cells with distinct lipid droplets were observed; Meanwhile, transfection with the inhibitor of miR-210 could markedly decrease differentiation-specific factors at the transcription level, which suggested the specific role of miR-210 in promoting adipogenesis. Tcf7l2, the predicted target of miR-210, is a transcription factor triggering the downstream responsive genes of WNT signaling, was blocked at transcription level. Furthermore, the activity of luciferase reporter bearing Tcf7l2 mRNA 3' UTR was decreased after co-transfection with miR-210 in HEK-293FT cells. Last but not least, the protein expression level of β-catenin was increased in the lithium (LiCl treated 3T3-L1 cells after transfection with miR-210. These

  2. Wnt9a signaling is required for joint integrity and regulation of Ihh during chondrogenesis.

    Science.gov (United States)

    Später, Daniela; Hill, Theo P; O'sullivan, Roderick J; Gruber, Michaela; Conner, David A; Hartmann, Christine

    2006-08-01

    Joints, which separate skeleton elements, serve as important signaling centers that regulate the growth of adjacent cartilage elements by controlling proliferation and maturation of chondrocytes. Accurate chondrocyte maturation is crucial for endochondral ossification and for the ultimate size of skeletal elements, as premature or delayed maturation results predominantly in shortened elements. Wnt9a has previously been implicated as being a player in joint induction, based on gain-of function experiments in chicken and mouse. We show that loss of Wnt9a does not affect joint induction, but results to synovial chondroid metaplasia in some joints. This phenotype can be enhanced by removal of an additional Wnt gene, Wnt4, suggesting that Wnts are playing a crucial role in directing bi-potential chondro-synovioprogenitors to become synovial connective tissue, by actively suppressing their chondrogenic potential. Furthermore, we show that Wnt9a is a temporal and spatial regulator of Indian hedgehog (Ihh), a central player of skeletogenesis. Loss of Wnt9a activity results in transient downregulation of Ihh and reduced Ihh-signaling activity at E12.5-E13.5. The canonical Wnt/beta-catenin pathway probably mediates regulation of Ihh expression in prehypertrophic chondrocytes by Wnt9a, because embryos double-heterozygous for Wnt9a and beta-catenin show reduced Ihh expression, and in vivo chromatin immunoprecipitation demonstrates a direct interaction between the beta-catenin/Lef1 complex and the Ihh promoter.

  3. Canonical Wnts, specifically Wnt-10b, show ability to maintain dermal papilla cells

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    Ouji, Yukiteru, E-mail: oujix@naramed-u.ac.jp; Nakamura-Uchiyama, Fukumi; Yoshikawa, Masahide, E-mail: myoshika@naramed-u.ac.jp

    2013-08-30

    Highlights: •First report on effects of various Wnts on DP cells. •Wnt-10b promoted trichogenesis, while Wnt-3a showed to a limited extent. •Canonical Wnts, specifically Wnt-10b, is important for DP cells maintenance. -- Abstract: Although Wnts are expressed in hair follicles (HFs) and considered to be crucial for maintaining dermal papilla (DP) cells, the functional differences among them remain largely unknown. In the present study, we investigated the effects of Wnts (Wnt-3a, 5a, 10b, 11) on the proliferation of mouse-derived primary DP cells in vitro as well as their trichogenesis-promoting ability using an in vivo skin reconstitution protocol. Wnt-10b promoted cell proliferation and trichogenesis, while Wnt-3a showed those abilities to a limited extent, and Wnt-5a and 11 had no effects. Furthermore, we investigated the effects of these Wnts on cultured DP cells obtained from versican-GFP transgenic mice and found that Wnt-10b had a potent ability to sustain their GFP-positivity. These results suggest that canonical Wnts, specifically Wnt-10b, play important roles in the maintenance of DP cells and trichogenesis.

  4. The Wnt/β-catenin pathway is deregulated in cemento-ossifying fibromas.

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    Pereira, Thaís Dos Santos Fontes; Diniz, Marina Gonçalves; França, Josiane Alves; Moreira, Rennan Garcias; Menezes, Grazielle Helena Ferreira de; Sousa, Sílvia Ferreira de; Castro, Wagner Henriques de; Gomes, Carolina Cavaliéri; Gomez, Ricardo Santiago

    2018-02-01

    The molecular pathogenesis of cemento ossifying fibroma (COF) is unclear. The purpose of this study was to investigate mutations in 50 oncogenes and tumor suppressor genes, including APC and CTNNB1, in which mutations in COF have been previously reported. In addition, we assessed the transcriptional levels of the Wnt/β-catenin pathway genes in COF. We used a quantitative polymerase chain reaction array to evaluate the transcriptional levels of 44 Wnt/β-catenin pathway genes in 6 COF samples, in comparison with 6 samples of healthy jaws. By using next-generation sequencing (NGS) in 7 COF samples, we investigated approximately 2800 mutations in 50 genes. The expression assay revealed 12 differentially expressed Wnt/β-catenin pathway genes in COF, including the upregulation of CTNNB1, TCF7, NKD1, and WNT5 A, and downregulation of CTNNBIP1, FRZB, FZD6, RHOU, SFRP4, WNT10 A, WNT3 A, and WNT4, suggesting activation of the Wnt/β-catenin signaling pathway. NGS revealed 5 single nucleotide variants: TP53 (rs1042522), PIK3 CA (rs2230461), MET (rs33917957), KIT (rs3822214), and APC (rs33974176), but none of them was pathogenic. Although NGS detected no oncogenic mutation, deregulation of key Wnt/β-catenin signaling pathway genes appears to be relevant to the molecular pathogenesis of COF. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Endocardial to myocardial notch-wnt-bmp axis regulates early heart valve development.

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    Yidong Wang

    Full Text Available Endocardial to mesenchymal transformation (EMT is a fundamental cellular process required for heart valve formation. Notch, Wnt and Bmp pathways are known to regulate this process. To further address how these pathways coordinate in the process, we specifically disrupted Notch1 or Jagged1 in the endocardium of mouse embryonic hearts and showed that Jagged1-Notch1 signaling in the endocardium is essential for EMT and early valvular cushion formation. qPCR and RNA in situ hybridization assays reveal that endocardial Jagged1-Notch1 signaling regulates Wnt4 expression in the atrioventricular canal (AVC endocardium and Bmp2 in the AVC myocardium. Whole embryo cultures treated with Wnt4 or Wnt inhibitory factor 1 (Wif1 show that Bmp2 expression in the AVC myocardium is dependent on Wnt activity; Wnt4 also reinstates Bmp2 expression in the AVC myocardium of endocardial Notch1 null embryos. Furthermore, while both Wnt4 and Bmp2 rescue the defective EMT resulting from Notch inhibition, Wnt4 requires Bmp for its action. These results demonstrate that Jagged1-Notch1 signaling in endocardial cells induces the expression of Wnt4, which subsequently acts as a paracrine factor to upregulate Bmp2 expression in the adjacent AVC myocardium to signal EMT.

  6. Mapping of Wnt-Frizzled interactions by multiplex CRISPR targeting of receptor gene families.

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    Voloshanenko, Oksana; Gmach, Philipp; Winter, Jan; Kranz, Dominique; Boutros, Michael

    2017-11-01

    Signaling pathway modules are often encoded by several closely related paralogous genes that can have redundant roles and are therefore difficult to analyze by loss-of-function analysis. A typical example is the Wnt signaling pathway, which in mammals is mediated by 19 Wnt ligands that can bind to 10 Frizzled (FZD) receptors. Although significant progress in understanding Wnt-FZD receptor interactions has been made in recent years, tools to generate systematic interaction maps have been largely lacking. Here we generated cell lines with multiplex mutant alleles of FZD1 , FZD2 , and FZD7 and demonstrate that these cells are unresponsive to canonical Wnt ligands. Subsequently, we performed genetic rescue experiments with combinations of FZDs and canonical Wnts to create a functional ligand-receptor interaction map. These experiments showed that whereas several Wnt ligands, such as Wnt3a, induce signaling through a broad spectrum of FZD receptors, others, such as Wnt8a, act through a restricted set of FZD genes. Together, our results map functional interactions of FZDs and 10 Wnt ligands and demonstrate how multiplex targeting by clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 can be used to systematically elucidate the functions of multigene families.-Voloshanenko, O., Gmach, P., Winter, J., Kranz, D., Boutros, M. Mapping of Wnt-Frizzled interactions by multiplex CRISPR targeting of receptor gene families. © The Author(s).

  7. Inhibition of adipocytogenesis by canonical WNT signaling in human mesenchymal stem cells

    International Nuclear Information System (INIS)

    Shen, Longxiang; Glowacki, Julie; Zhou, Shuanhu

    2011-01-01

    The WNT signaling pathway plays important roles in the self-renewal and differentiation of mesenchymal stem cells (MSCs). Little is known about WNT signaling in adipocyte differentiation of human MSCs. In this study, we tested the hypothesis that canonical and non-canonical WNTs differentially regulate in vitro adipocytogenesis in human MSCs. The expression of adipocyte gene PPARγ2, lipoprotein lipase, and adipsin increased during adipocytogenesis of hMSCs. Simultaneously, the expression of canonical WNT2, 10B, 13, and 14 decreased, whereas non-canonical WNT4 and 11 increased, and WNT5A was unchanged. A small molecule WNT mimetic, SB-216763, increased accumulation of β-catenin protein, inhibited induction of WNT4 and 11 and inhibited adipocytogenesis. In contrast, knockdown of β-catenin with siRNA resulted in spontaneous adipocytogenesis. These findings support the view that canonical WNT signaling inhibits and non-canonical WNT signaling promotes adipocytogenesis in adult human marrow-derived mesenchymal stem cells.

  8. A Study of LGK974 in Patients With Malignancies Dependent on Wnt Ligands

    Science.gov (United States)

    2018-02-22

    Pancreatic Cancer; BRAF Mutant Colorectal Cancer; Other Tumor Types With Documented Genetic Alterations Upstream in the Wnt Signaling Pathway; Melanoma; Triple Negative Breast Cancer; Head and Neck Cancer

  9. Wnt Ligands as a Part of the Stem Cell Niche in the Intestine and the Liver.

    Science.gov (United States)

    Degirmenci, Bahar; Hausmann, George; Valenta, Tomas; Basler, Konrad

    2018-01-01

    The term "Wnt signaling" does not refer to one uniform signal transduction cascade. Instead, it describes the multiple discrete signals elicited by Wnt ligands following their interaction with distinct receptor complexes. The interaction of stem cells with niche cells is coordinated by the involvement of different signaling pathways, including Wnt signaling. The stem cell populations are highly sensitive to modulation of Wnt pathway activity. Wnt signaling is of paramount importance for stem cell self-renewal, survival, proliferation, differentiation, movement, and cell polarity. Aberrant activation of Wnt/β-catenin signaling is associated with the pathology of many types of cancer, such as colorectal cancer and hepatocellular carcinoma. Importantly, although often initiated by mutation(s) downstream of the Wnt-receptor complex, the progression of colorectal cancer still seems to be augmented by Wnt ligand-mediated signaling. This chapter focuses on the role of Wnt ligands in the intestine and the liver during homeostasis and cancer. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Wnt5a Regulates the Assembly of Human Adipose Derived Stromal Vascular Fraction-Derived Microvasculatures.

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    Venkat M Ramakrishnan

    Full Text Available Human adipose-derived stromal vascular fraction (hSVF cells are an easily accessible, heterogeneous cell system that can spontaneously self-assemble into functional microvasculatures in vivo. However, the mechanisms underlying vascular self-assembly and maturation are poorly understood, therefore we utilized an in vitro model to identify potential in vivo regulatory mechanisms. We utilized passage one (P1 hSVF because of the rapid UEA1+ endothelium (EC loss at even P2 culture. We exposed hSVF cells to a battery of angiogenesis inhibitors and found that the pan-Wnt inhibitor IWP2 produced the most significant hSVF-EC networking decrease (~25%. To determine which Wnt isoform(s and receptor(s may be involved, hSVF was screened by PCR for isoforms associated with angiogenesis, with only WNT5A and its receptor, FZD4, being expressed for all time points observed. Immunocytochemistry confirmed Wnt5a protein expression by hSVF. To see if Wnt5a alone could restore IWP2-induced EC network inhibition, recombinant human Wnt5a (0-150 ng/ml was added to IWP2-treated cultures. The addition of rhWnt5a significantly increased EC network area and significantly decreased the ratio of total EC network length to EC network area compared to untreated controls. To determine if Wnt5a mediates in vivo microvascular self-assembly, 3D hSVF constructs containing an IgG isotype control, anti-Wnt5a neutralizing antibody or rhWnt5a were implanted subcutaneously for 2w in immune compromised mice. Compared to IgG controls, anti-Wnt5a treatment significantly reduced vessel length density by ~41%, while rhWnt5a significantly increased vessel length density by ~62%. However, anti-Wnt5a or rhWnt5a did not significantly affect the density of segments and nodes, both of which measure vascular complexity. Taken together, this data demonstrates that endogenous Wnt5a produced by hSVF plays a regulatory role in microvascular self-assembly in vivo. These findings also suggest that

  11. Spatio-temporal expression patterns of Wnt signaling pathway during the development of temporomandibular condylar cartilage.

    Science.gov (United States)

    Chen, Kan; Quan, Huixin; Chen, Gang; Xiao, Di

    2017-11-01

    There is a growing body of evidence supporting the involvement of the Wnt signaling pathway in various aspects of skeletal and joint development; however, it is unclear whether it is involved in the process of temporomandibular joint development. In order to clarify this issue, we examined the spatio-temporal distribution of mRNAs and proteins of the Wnt family during the formation of the mandibular condylar cartilage at the prenatal and postnatal stages. An in situ hybridization test revealed no mRNAs of β-catenin and Axin2 during early mesenchymal condensation; the ligands surveyed in this study (including Wnt-4, 5a, and 9a) were clearly detected at various ranges of expression, mainly in the condylar blastema and later distinct cartilaginous layers. Apart from β-catenin and Axin2, the Wnt family members surveyed in this study, including Lef-1, were found to be immunopositive during early chondrogenesis in the condylar cartilage at E14.5. After distinct chondrocyte layers were identified within the cartilage at E16.5, the expression of the Wnt signaling members was different and mainly restricted to proliferating cells and mineralized hypertrophic chondrocytes. In the adult mandibular condylar cartilage, the Wnt-4 mRNA, as well as the Wnt-4 and Wnt-9a proteins, was not observed. Our findings demonstrated that the Wnt signaling pathway was associated with the development of mandibular condylar cartilage. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Selective modulation of Wnt ligands and their receptors in adipose tissue by chronic hyperadiponectinemia.

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    Nobuhiko Wada

    Full Text Available BACKGROUND: Adiponectin-transgenic mice had many small adipocytes in both subcutaneous and visceral adipose tissues, and showed higher sensitivity to insulin, longer life span, and reduced chronic inflammation. We hypothesized that adiponectin regulates Wnt signaling in adipocytes and thereby modulates adipocyte proliferation and chronic inflammation in adipose tissue. MATERIALS AND METHODS: We examined the expression of all Wnt ligands and their receptors and the activity of Wnt signaling pathways in visceral adipose tissue from wild-type mice and two lines of adiponectin-transgenic mice. The effects of adiponectin were also investigated in cultured 3T3-L1 cells. RESULTS: The Wnt5b, Wnt6, Frizzled 6 (Fzd6, and Fzd9 genes were up-regulated in both lines of transgenic mice, whereas Wnt1, Wnt2, Wnt5a, Wnt9b, Wnt10b, Wnt11, Fzd1, Fzd2, Fzd4, Fzd7, and the Fzd coreceptor low-density-lipoprotein receptor-related protein 6 (Lrp6 were reduced. There was no difference in total β-catenin levels in whole-cell extracts, non-phospho-β-catenin levels in nuclear extracts, or mRNA levels of β-catenin target genes, indicating that hyperadiponectinemia did not affect canonical Wnt signaling. In contrast, phosphorylated calcium/calmodulin-dependent kinase II (p-CaMKII and phosphorylated Jun N-terminal kinase (p-JNK were markedly reduced in adipose tissue from the transgenic mice. The adipose tissue of the transgenic mice consisted of many small cells and had increased expression of adiponectin, whereas cyclooxygenase-2 expression was reduced. Wnt5b expression was elevated in preadipocytes of the transgenic mice and decreased in diet-induced obese mice, suggesting a role in adipocyte differentiation. Some Wnt genes, Fzd genes, and p-CaMKII protein were down-regulated in 3T3-L1 cells cultured with a high concentration of adiponectin. CONCLUSION: Chronic hyperadiponectinemia selectively modulated the expression of Wnt ligands, Fzd receptors and LRP coreceptors

  13. Aberrant Wnt signaling pathway in medial temporal lobe structures of Alzheimer's disease

    DEFF Research Database (Denmark)

    Riise, Jesper; Plath, Niels; Pakkenberg, Bente

    2015-01-01

    alterations of the intracellular Wnt pathway signaling components β-catenin, Gsk3β and Tcf7l1/Tcf3 and the phosphorylation state of β-catenin and Gsk3β in the hippocampus suggestive of a link between AD and aberrant canonical activity. Alterations in Gsk3β co-appeared with hippocampal kinase...... on isolated Wnt pathway components. Here, we provide the first comprehensive pathway-focused evaluation of the Wnt pathway in the entorhinal cortex and hippocampus of AD brains. Our data demonstrate altered Wnt pathway gene expression at all levels of the pathway in both medial temporal lobe regions...

  14. The Wnt signaling pathway in familial exudative vitreoretinopathy and Norrie disease.

    Science.gov (United States)

    Warden, Scott M; Andreoli, Christopher M; Mukai, Shizuo

    2007-01-01

    The Wnt signaling pathway is highly conserved among species and has an important role in many cell biological processes throughout the body. This signaling cascade is involved in regulating ocular growth and development, and recent findings indicate that this is particularly true in the retina. Mutations involving different aspects of the Wnt signaling pathway are being linked to several diseases of retinal development. The aim of this article is to first review the Wnt signaling pathway. We will then describe two conditions, familial exudative vitreoretinopathy (FEVR) and Norrie disease (ND), which have been shown to be caused in part by defects in the Wnt signaling cascade.

  15. Wnt16 Is Associated with Age-Related Bone Loss and Estrogen Withdrawal in Murine Bone.

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    Henry Todd

    Full Text Available Genome Wide Association Studies suggest that Wnt16 is an important contributor to the mechanisms controlling bone mineral density, cortical thickness, bone strength and ultimately fracture risk. Wnt16 acts on osteoblasts and osteoclasts and, in cortical bone, is predominantly derived from osteoblasts. This led us to hypothesize that low bone mass would be associated with low levels of Wnt16 expression and that Wnt16 expression would be increased by anabolic factors, including mechanical loading. We therefore investigated Wnt16 expression in the context of ageing, mechanical loading and unloading, estrogen deficiency and replacement, and estrogen receptor α (ERα depletion. Quantitative real time PCR showed that Wnt16 mRNA expression was lower in cortical bone and marrow of aged compared to young female mice. Neither increased nor decreased (by disuse mechanical loading altered Wnt16 expression in young female mice, although Wnt16 expression was decreased following ovariectomy. Both 17β-estradiol and the Selective Estrogen Receptor Modulator Tamoxifen increased Wnt16 expression relative to ovariectomy. Wnt16 and ERβ expression were increased in female ERα-/- mice when compared to Wild Type. We also addressed potential effects of gender on Wnt16 expression and while the expression was lower in the cortical bone of aged males as in females, it was higher in male bone marrow of aged mice compared to young. In the kidney, which we used as a non-bone reference tissue, Wnt16 expression was unaffected by age in either males or females. In summary, age, and its associated bone loss, is associated with low levels of Wnt16 expression whereas bone loss associated with disuse has no effect on Wnt16 expression. In the artificially loaded mouse tibia we observed no loading-related up-regulation of Wnt16 expression but provide evidence that its expression is influenced by estrogen receptor signaling. These findings suggest that while Wnt16 is not an

  16. Inflammation and hypoxia in the kidney: friends or foes?

    Science.gov (United States)

    Haase, Volker H

    2015-08-01

    Hypoxic injury is commonly associated with inflammatory-cell infiltration, and inflammation frequently leads to the activation of cellular hypoxia response pathways. The molecular mechanisms underlying this cross-talk during kidney injury are incompletely understood. Yamaguchi and colleagues identify CCAAT/enhancer-binding protein δ as a cytokine- and hypoxia-regulated transcription factor that fine-tunes hypoxia-inducible factor-1 signaling in renal epithelial cells and thus provide a novel molecular link between hypoxia and inflammation in kidney injury.

  17. Modification of bacterial cell survival by postirradiation hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Vexler, F B; Eidus, L Kh

    1986-01-27

    It is shown that postirradiation hypoxia affects the survival of E.coli. Hypoxic conditions immediately after a single-dose irradiation diminish cell survival in nutrient medium. Increasing time intervals between irradiation and hypoxia decrease the efficiency of the latter, while 1 h after irradiation hypoxia does not modify the survival of irradiated cells. These findings reveal that the mechanisms of action of postirradiation hypoxia on eu- and prokaryotic cells are similar.

  18. Overexpression of Hypoxia-Inducible Factor-1α Exacerbates Endothelial Barrier Dysfunction Induced by Hypoxia

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    Pei Wang

    2013-09-01

    Full Text Available Background/Aims: The mechanisms involved in endothelial barrier dysfunction induced by hypoxia are incompletely understood. There is debate about the role of hypoxia-inducible factor-1α (HIF-1α in endothelial barrier disruption. The aim of this study was to investigate the effect of genetic overexpression of HIF-1α on barrier function and the underlying mechanisms in hypoxic endothelial cells. Methods: The plasmid pcDNA3.1/V5-His-HIF-1α was stably transfected into human endothelial cells. The cells were exposed to normoxia or hypoxia. The mRNA and protein expressions of HIF-1α were detected by RT-PCR and Western blot respectively. The barrier function was assessed by measuring the transendothelial electrical resistance (TER. The Western blot analysis was used to determine the protein expression of glucose transporter-1 (GLUT-1, zonular occludens-1 (ZO-1, occludin, and myosin light chain kinase (MLCK in endothelial cells. The mRNA expression of proinflammatory cytokines was detected by qRT-PCR. Results: Genetic overexpression of HIF-1α significantly increased the mRNA and protein expression of HIF-1α in endothelial cells. The overexpression of HIF-1α enhanced the hypoxia-induced increase of HIF-1α and GLUT-1 protein expression. HIF-1α overexpression not only exacerbated hypoxia-induced endothelial barrier dysfunction but also augmented hypoxia-induced up-regulation of MLCK protein expression. HIF-1α overexpression also enhanced IL-1β, IL-6 and TNF-α mRNA expression. Conclusion: We provide evidence that genetic overexpression of HIF-1α aggravates the hypoxia-induced endothelial barrier dysfunction via enhancing the up-regulation of MLCK protein expression caused by hypoxia, suggesting a potential role for HIF-1α in the pathogenesis of endothelial barrier dysfunction in hypoxia.

  19. Analysis of hypoxia and hypoxia-like states through metabolite profiling.

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    Julie E Gleason

    Full Text Available In diverse organisms, adaptation to low oxygen (hypoxia is mediated through complex gene expression changes that can, in part, be mimicked by exposure to metals such as cobalt. Although much is known about the transcriptional response to hypoxia and cobalt, little is known about the all-important cell metabolism effects that trigger these responses.Herein we use a low molecular weight metabolome profiling approach to identify classes of metabolites in yeast cells that are altered as a consequence of hypoxia or cobalt exposures. Key findings on metabolites were followed-up by measuring expression of relevant proteins and enzyme activities. We find that both hypoxia and cobalt result in a loss of essential sterols and unsaturated fatty acids, but the basis for these changes are disparate. While hypoxia can affect a variety of enzymatic steps requiring oxygen and heme, cobalt specifically interferes with diiron-oxo enzymatic steps for sterol synthesis and fatty acid desaturation. In addition to diiron-oxo enzymes, cobalt but not hypoxia results in loss of labile 4Fe-4S dehydratases in the mitochondria, but has no effect on homologous 4Fe-4S dehydratases in the cytosol. Most striking, hypoxia but not cobalt affected cellular pools of amino acids. Amino acids such as aromatics were elevated whereas leucine and methionine, essential to the strain used here, dramatically decreased due to hypoxia induced down-regulation of amino acid permeases.These studies underscore the notion that cobalt targets a specific class of iron proteins and provide the first evidence for hypoxia effects on amino acid regulation. This research illustrates the power of metabolite profiling for uncovering new adaptations to environmental stress.

  20. Effects of intermittent hypoxia on running economy.

    Science.gov (United States)

    Burtscher, M; Gatterer, H; Faulhaber, M; Gerstgrasser, W; Schenk, K

    2010-09-01

    We investigated the effects of two 5-wk periods of intermittent hypoxia on running economy (RE). 11 male and female middle-distance runners were randomly assigned to the intermittent hypoxia group (IHG) or to the control group (CG). All athletes trained for a 13-wk period starting at pre-season until the competition season. The IHG spent additionally 2 h at rest on 3 days/wk for the first and the last 5 weeks in normobaric hypoxia (15-11% FiO2). RE, haematological parameters and body composition were determined at low altitude (600 m) at baseline, after the 5 (th), the 8 (th) and the 13 (th) week of training. RE, determined by the relative oxygen consumption during submaximal running, (-2.3+/-1.2 vs. -0.3+/-0.7 ml/min/kg, Ptraining phase. Georg Thieme Verlag KG Stuttgart . New York.

  1. Kinetic modeling in PET imaging of hypoxia

    Science.gov (United States)

    Li, Fan; Joergensen, Jesper T; Hansen, Anders E; Kjaer, Andreas

    2014-01-01

    Tumor hypoxia is associated with increased therapeutic resistance leading to poor treatment outcome. Therefore the ability to detect and quantify intratumoral oxygenation could play an important role in future individual personalized treatment strategies. Positron Emission Tomography (PET) can be used for non-invasive mapping of tissue oxygenation in vivo and several hypoxia specific PET tracers have been developed. Evaluation of PET data in the clinic is commonly based on visual assessment together with semiquantitative measurements e.g. standard uptake value (SUV). However, dynamic PET contains additional valuable information on the temporal changes in tracer distribution. Kinetic modeling can be used to extract relevant pharmacokinetic parameters of tracer behavior in vivo that reflects relevant physiological processes. In this paper, we review the potential contribution of kinetic analysis for PET imaging of hypoxia. PMID:25250200

  2. Cutaneous vascular and core temperature responses to sustained cold exposure in hypoxia.

    Science.gov (United States)

    Simmons, Grant H; Barrett-O'Keefe, Zachary; Minson, Christopher T; Halliwill, John R

    2011-10-01

    We tested the effect of hypoxia on cutaneous vascular regulation and defense of core temperature during cold exposure. Twelve subjects had two microdialysis fibres placed in the ventral forearm and were immersed to the sternum in a bathtub on parallel study days (normoxia and poikilocapnic hypoxia with an arterial O(2) saturation of 80%). One fibre served as the control (1 mM propranolol) and the other received 5 mM yohimbine (plus 1 mM propranolol) to block adrenergic receptors. Skin blood flow was assessed at each site (laser Doppler flowmetry), divided by mean arterial pressure to calculate cutaneous vascular conductance (CVC), and scaled to baseline. Cold exposure was first induced by a progressive reduction in water temperature from 36 to 23°C over 30 min to assess cutaneous vascular regulation, then by clamping the water temperature at 10°C for 45 min to test defense of core temperature. During normoxia, cold stress reduced CVC in control (-44 ± 4%) and yohimbine sites (-13 ± 7%; both P cooling but resulted in greater reductions in CVC in control (-67 ± 7%) and yohimbine sites (-35 ± 11%) during cooling (both P cooling rate during the second phase of cold exposure was unaffected by hypoxia (-1.81 ± 0.23°C h(-1) in normoxia versus -1.97 ± 0.33°C h(-1) in hypoxia; P > 0.05). We conclude that hypoxia increases cutaneous (non-noradrenergic) vasoconstriction during prolonged cold exposure, while core cooling rate is not consistently affected.

  3. Fetal blood vessel count increases in compensation of hypoxia in premature placentas

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    K. Kartini

    2015-04-01

    Full Text Available Background Prematurity refers to live births before 37 weeks of gestation, wherein the baby is born before the body and its organ systems achieve perfect maturity, and this disorder is still a global problem. The high incidence of prematurity is a problem in developing and also in developed countries. Certain conditions accompanying pregnancies like preeclampsia, infection, and placental insufficiency, may trigger uterine hypoxia, causing premature birth. The placental condition is related to the intra-uterine fetal condition. In prolonged placental hypoxia, there occurs a compensatory mechanism, i.e. an increase in placental angiogenesis. This study aimed to evaluate the effect of hypoxia on fetal blood vessel count as compensatory mechanism for tissue hypoxia. Methods An observational-analytical cross-sectional design using paraffin blocks of conserved premature placentas, comprising 31 samples of hypoxic premature placentas and 28 samples of non-hypoxic premature placentas, selected using non-random consecutive sampling. The samples were made into slides and stained with hematoxylin-eosin for assessment of histological structure, including fetal blood vessel count and integrity, villus conditions, syncytiotrophoblastic nuclear changes, and syncytiotrophoblastic nuclear aggregation. Mann-Whitney test was used to compare the difference of blood vessel count between groups. Results Assessment of histological structure showed a significant increase in fetal blood vessel count in the hypoxic group [8.00 (5-15] as compared with the non-hypoxic group [7.50 (3-15]. Conclusion The hypoxia in premature placentas caused an increase in the number of fetal blood vessels as a form of compensation for disturbed oxygen homeostasis.

  4. Fetal blood vessel count increases in compensation of hypoxia in premature placentas

    Directory of Open Access Journals (Sweden)

    K Kartini

    2016-02-01

    Full Text Available BACKGROUND Prematurity refers to live births before 37 weeks of gestation, wherein the baby is born before the body and its organ systems achieve perfect maturity, and this disorder is still a global problem. The high incidence of prematurity is a problem in developing and also in developed countries. Certain conditions accompanying pregnancies like preeclampsia, infection, and placental insufficiency, may trigger uterine hypoxia, causing premature birth. The placental condition is related to the intra-uterine fetal condition. In prolonged placental hypoxia, there occurs a compensatory mechanism, i.e. an increase in placental angiogenesis. This study aimed to evaluate the effect of hypoxia on fetal blood vessel count as compensatory mechanism for tissue hypoxia. METHODS An observational-analytical cross-sectional design using paraffin blocks of conserved premature placentas, comprising 31 samples of hypoxic premature placentas and 28 samples of non-hypoxic premature placentas, selected using non-random consecutive sampling. The samples were made into slides and stained with hematoxylin-eosin for assessment of histological structure, including fetal blood vessel count and integrity, villus conditions, syncytiotrophoblastic nuclear changes, and syncytiotrophoblastic nuclear aggregation. Mann-Whitney test was used to compare the difference of blood vessel count between groups. RESULTS Assessment of histological structure showed a significant increase in fetal blood vessel count in the hypoxic group [8.00 (5-15] as compared with the non-hypoxic group [7.50 (3-15]. CONCLUSION The hypoxia in premature placentas caused an increase in the number of fetal blood vessels as a form of compensation for disturbed oxygen homeostasis.

  5. Synaptic Wnt/GSK3β Signaling Hub in Autism

    Science.gov (United States)

    Caracci, Mario O.; Ávila, Miguel E.; De Ferrari, Giancarlo V.

    2016-01-01

    Hundreds of genes have been associated with autism spectrum disorders (ASDs) and the interaction of weak and de novo variants derive from distinct autistic phenotypes thus making up the “spectrum.” The convergence of these variants in networks of genes associated with synaptic function warrants the study of cell signaling pathways involved in the regulation of the synapse. The Wnt/β-catenin signaling pathway plays a central role in the development and regulation of the central nervous system and several genes belonging to the cascade have been genetically associated with ASDs. In the present paper, we review basic information regarding the role of Wnt/β-catenin signaling in excitatory/inhibitory balance (E/I balance) through the regulation of pre- and postsynaptic compartments. Furthermore, we integrate information supporting the role of the glycogen synthase kinase 3β (GSK3β) in the onset/development of ASDs through direct modulation of Wnt/β-catenin signaling. Finally, given GSK3β activity as key modulator of synaptic plasticity, we explore the potential of this kinase as a therapeutic target for ASD. PMID:26881141

  6. Response of skeletal muscle mitochondria to hypoxia.

    Science.gov (United States)

    Hoppeler, Hans; Vogt, Michael; Weibel, Ewald R; Flück, Martin

    2003-01-01

    This review explores the current concepts relating the structural and functional modifications of skeletal muscle mitochondria to the molecular mechanisms activated when organisms are exposed to a hypoxic environment. In contrast to earlier assumptions it is now established that permanent or long-term exposure to severe environmental hypoxia decreases the mitochondrial content of muscle fibres. Oxidative muscle metabolism is shifted towards a higher reliance on carbohydrates as a fuel, and intramyocellular lipid substrate stores are reduced. Moreover, in muscle cells of mountaineers returning from the Himalayas, we find accumulations of lipofuscin, believed to be a mitochondrial degradation product. Low mitochondrial contents are also observed in high-altitude natives such as Sherpas. In these subjects high-altitude performance seems to be improved by better coupling between ATP demand and supply pathways as well as better metabolite homeostasis. The hypoxia-inducible factor 1 (HIF-1) has been identified as a master regulator for the expression of genes involved in the hypoxia response, such as genes coding for glucose transporters, glycolytic enzymes and vascular endothelial growth factor (VEGF). HIF-1 achieves this by binding to hypoxia response elements in the promoter regions of these genes, whereby the increase of HIF-1 in hypoxia is the consequence of a reduced degradation of its dominant subunit HIF-1a. A further mechanism that seems implicated in the hypoxia response of muscle mitochondria is related to the formation of reactive oxygen species (ROS) in mitochondria during oxidative phosphorylation. How exactly ROS interfere with HIF-1a as well as MAP kinase and other signalling pathways is debated. The current evidence suggests that mitochondria themselves could be important players in oxygen sensing.

  7. ENU mutagenesis reveals that Notchless homolog 1 (Drosophila affects Cdkn1a and several members of the Wnt pathway during murine pre-implantation development

    Directory of Open Access Journals (Sweden)

    Lossie Amy C

    2012-12-01

    Full Text Available Abstract Background Our interests lie in determining the genes and genetic pathways that are important for establishing and maintaining maternal-fetal interactions during pregnancy. Mutation analysis targeted to a 34 Mb domain flanked by Trp53 and Wnt3 demonstrates that this region of mouse chromosome 11 contains a large number of essential genes. Two mutant alleles (l11Jus1 and l11Jus4, which fall into the same complementation group, survive through implantation but fail prior to gastrulation. Results Through a positional cloning strategy, we discovered that these homozygous mutant alleles contain non-conservative missense mutations in the Notchless homolog 1 (Drosophila (Nle1 gene. NLE1 is a member of the large WD40-repeat protein family, and is thought to signal via the canonical NOTCH pathway in vertebrates. However, the phenotype of the Nle1 mutant mice is much more severe than single Notch receptor mutations or even in animals in which NOTCH signaling is blocked. To test the hypothesis that NLE1 functions in multiple signaling pathways during pre-implantation development, we examined expression of multiple Notch downstream target genes, as well as select members of the Wnt pathway in wild-type and mutant embryos. We did not detect altered expression of any primary members of the Notch pathway or in Notch downstream target genes. However, our data reveal that Cdkn1a, a NOTCH target, was upregulated in Nle1 mutants, while several members of the Wnt pathway are downregulated. In addition, we found that Nle1 mutant embryos undergo caspase-mediated apoptosis as hatched blastocysts, but not as morulae or blastocysts. Conclusions Taken together, these results uncover potential novel functions for NLE1 in the WNT and CDKN1A pathways during embryonic development in mammals.

  8. Strabismus-mediated primary archenteron invagination is uncoupled from Wnt/β-catenin-dependent endoderm cell fate specification in Nematostella vectensis (Anthozoa, Cnidaria: Implications for the evolution of gastrulation

    Directory of Open Access Journals (Sweden)

    Kumburegama Shalika

    2011-01-01

    Full Text Available Abstract Background Gastrulation is a uniquely metazoan character, and its genesis was arguably the key step that enabled the remarkable diversification within this clade. The process of gastrulation involves two tightly coupled events during embryogenesis of most metazoans. Morphogenesis produces a distinct internal epithelial layer in the embryo, and this epithelium becomes segregated as an endoderm/endomesodermal germ layer through the activation of a specific gene regulatory program. The developmental mechanisms that induced archenteron formation and led to the segregation of germ layers during metazoan evolution are unknown. But an increased understanding of development in early diverging taxa at the base of the metazoan tree may provide insights into the origins of these developmental mechanisms. Results In the anthozoan cnidarian Nematostella vectensis, initial archenteron formation begins with bottle cell-induced buckling of the blastula epithelium at the animal pole. Here, we show that bottle cell formation and initial gut invagination in Nematostella requires NvStrabismus (NvStbm, a maternally-expressed core component of the Wnt/Planar Cell Polarity (PCP pathway. The NvStbm protein is localized to the animal pole of the zygote, remains asymmetrically expressed through the cleavage stages, and becomes restricted to the apical side of invaginating bottle cells at the blastopore. Antisense morpholino-mediated NvStbm-knockdown blocks bottle cell formation and initial archenteron invagination, but it has no effect on Wnt/ß-catenin signaling-mediated endoderm cell fate specification. Conversely, selectively blocking Wnt/ß-catenin signaling inhibits endoderm cell fate specification but does not affect bottle cell formation and initial archenteron invagination. Conclusions Our results demonstrate that Wnt/PCP-mediated initial archenteron invagination can be uncoupled from Wnt/ß-catenin-mediated endoderm cell fate specification in

  9. The impact of hypoxia on oncolytic virotherapy

    Directory of Open Access Journals (Sweden)

    Guo ZS

    2011-11-01

    Full Text Available Z Sheng GuoUniversity of Pittsburgh Cancer Institute and Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USAAbstract: The hypoxic tumor microenvironment plays significant roles in tumor cell metabolism and survival, tumor growth, and progression. Hypoxia modulates target genes in target cells mainly through an oxygen-sensing signaling pathway mediated by hypoxia-inducible factor of transcription factors. As a result, hypoxic tumor cells are resistant to conventional therapeutics such as radiation and chemotherapy. Oncolytic virotherapy may be a promising novel therapeutic for hypoxic cancer. Some oncolytic viruses are better adapted than others to the hypoxic tumor environment. Replication of adenoviruses from both groups B and C is inhibited, yet replication of herpes simplex virus is enhanced. Hypoxia seems to exert little or no effect on the replication of other oncolytic viruses. Vaccinia virus displayed increased cytotoxicity in some hypoxic cancer cells even though viral protein synthesis and transgene expression were not affected. Vesicular stomatitis virus replicated to similar levels in both hypoxic and normoxic conditions, and is effective for killing hypoxic cancer cells. However, vesicular stomatitis virus and reovirus, but not encephalomyocarditis virus, are sensitive to elevated levels of hypoxia-inducible factor-1α in renal cancer cells with the loss of von Hippel–Lindau tumor suppressor protein, because elevated hypoxia-inducible factor activity confers dramatically enhanced resistance to cytotoxicity mediated by vesicular stomatitis virus or reovirus. A variety of hypoxia-selective and tumor-type-specific oncolytic adenoviruses, generated by incorporating hypoxia-responsive elements into synthetic promoters to control essential genes for viral replication or therapeutic genes, have been shown to be safe and efficacious. Hypoxic tumor-homing macrophages can function effectively as carrier

  10. Functional Consequences of 17q21.31/WNT3-WNT9B Amplification in hPSCs with Respect to Neural Differentiation

    Directory of Open Access Journals (Sweden)

    Chun-Ting Lee

    2015-02-01

    Full Text Available Human pluripotent stem cell (hPSC lines exhibit repeated patterns of genetic variation, which can alter in vitro properties as well as suitability for clinical use. We examined associations between copy-number variations (CNVs on chromosome 17 and hPSC mesodiencephalic dopaminergic (mDA differentiation. Among 24 hPSC lines, two karyotypically normal lines, BG03 and CT3, and BG01V2, with trisomy 17, exhibited amplification of the WNT3/WNT9B region and rapid mDA differentiation. In hPSC lines with amplified WNT3/WNT9B, basic fibroblast growth factor (bFGF signaling through mitogen-activated protein kinase (MAPK/ERK amplifies canonical WNT signaling by phosphorylating LRP6, resulting in enhanced undifferentiated proliferation. When bFGF is absent, noncanonical WNT signaling becomes dominant due to upregulation of SIAH2, enhancing JNK signaling and promoting loss of pluripotency. When bFGF is present during mDA differentiation, stabilization of canonical WNT signaling causes upregulation of LMX1A and mDA induction. Therefore, CNVs in 17q21.31, a “hot spot” for genetic variation, have multiple and complex effects on hPSC cellular phenotype.

  11. Effect of activation of canonical Wnt signaling by the Wnt-3a protein on the susceptibility of PC12 cells to oxidative and apoptotic insults

    International Nuclear Information System (INIS)

    Kawamoto, E.M.; Gleichmann, M.; Yshii, L.M.; Sá Lima, L. de; Mattson, M.P.; Scavone, C.

    2011-01-01

    Wnt proteins are involved in tissue development and their signaling pathways play an important role during embryogenesis. Wnt signaling can promote cell survival, which is beneficial for neurons, but could also lead to tumor development in different tissues. The present study investigated the effects of a Wnt protein on the susceptibility of a neural tumor cell line (PC12 cells) to the cytotoxic compounds ferrous sulfate (10 mM), staurosporine (100 and 500 nM), 3-nitropropionic acid (5 mM), and amyloid β-peptide (Aβ 25-35 ; 50 µM). Cells (1 × 10 6 cells/mL) were treated with the Wnt-3a recombinant peptide (200 ng/mL) for 24 h before exposure to toxic insults. The Wnt-3a protein partially protected PC12 cells, with a 6-15% increase in cell viability in the presence of toxic agents, similar to the effect measured using the MTT and lactate dehydrogenase cell viability assays. The Wnt-3a protein increased protein expression of β-catenin by 52% compared to control. These findings suggest that Wnt signaling can protect neural cells against apoptosis induced by toxic agents, which are relevant to the pathogenesis of Alzheimer's and Huntington's diseases

  12. Transcriptomic analysis of Portunus trituberculatus reveals a critical role for WNT4 and WNT signalling in limb regeneration.

    Science.gov (United States)

    Liu, Lei; Fu, Yuanyuan; Zhu, Fang; Mu, Changkao; Li, Ronghua; Song, Weiwei; Shi, Ce; Ye, Yangfang; Wang, Chunlin

    2018-06-05

    The swimming crab (Portunus trituberculatus) is among the most economically important seawater crustacean species in Asia. Despite its commercial importance and being well-studied status, genomic and transcriptomic data are scarce for this crab species. In the present study, limb bud tissue was collected at different developmental stages post amputation for transcriptomic analysis. Illumina RNA-sequencing was applied to characterise the limb regeneration transcriptome and identify the most characteristic genes. A total of 289,018 transcripts were obtained by clustering and assembly of clean reads, producing 150,869 unigenes with an average length of 956 bp. Subsequent analysis revealed WNT signalling as the key pathway involved in limb regeneration, with WNT4 a key mediator. Overall, limb regeneration appears to be regulated by multiple signalling pathways, with numerous cell differentiation, muscle growth, moult, metabolism, and immune-related genes upregulated, including WNT4, LAMA, FIP2, FSTL5, TNC, HUS1, SWI5, NCGL, SLC22, PLA2, Tdc2, SMOX, GDH, and SMPD4. This is the first experimental study done on regenerating claws of P. trituberculatus. These findings expand existing sequence resources for crab species, and will likely accelerate research into regeneration and development in crustaceans, particularly functional studies on genes involved in limb regeneration. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Transcriptome analysis of Wnt3a-treated triple-negative breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Sylvie Maubant

    Full Text Available The canonical Wnt/β-catenin pathway is activated in triple-negative breast cancer (TNBC. The activation of this pathway leads to the expression of specific target genes depending on the cell/tissue context. Here, we analyzed the transcriptome of two different TNBC cell lines to define a comprehensive list of Wnt target genes. The treatment of cells with Wnt3a for 6h up-regulated the expression (fold change > 1.3 of 59 genes in MDA-MB-468 cells and 241 genes in HCC38 cells. Thirty genes were common to both cell lines. Beta-catenin may also be a transcriptional repressor and we found that 18 and 166 genes were down-regulated in response to Wnt3a treatment for 6h in MDA-MB-468 and HCC38 cells, respectively, of which six were common to both cell lines. Only half of the activated and the repressed transcripts have been previously described as Wnt target genes. Therefore, our study reveals 137 novel genes that may be positively regulated by Wnt3a and 104 novel genes that may be negatively regulated by Wnt3a. These genes are involved in the Wnt pathway itself, and also in TGFβ, p53 and Hedgehog pathways. Thorough characterization of these novel potential Wnt target genes may reveal new regulators of the canonical Wnt pathway. The comparison of our list of Wnt target genes with those published in other cellular contexts confirms the notion that Wnt target genes are tissue-, cell line- and treatment-specific. Genes up-regulated in Wnt3a-stimulated cell lines were more strongly expressed in TNBC than in luminal A breast cancer samples. These genes were also overexpressed, but to a much lesser extent, in HER2+ and luminal B tumors. We identified 72 Wnt target genes higher expressed in TNBCs (17 with a fold change >1.3 which may reflect the chronic activation of the canonical Wnt pathway that occurs in TNBC tumors.

  14. Expression profile and function of Wnt signaling mechanisms in malignant mesothelioma cells

    International Nuclear Information System (INIS)

    Fox, Simon A.; Richards, Alex K.; Kusumah, Ivonne; Perumal, Vanathi; Bolitho, Erin M.; Mutsaers, Steven E.; Dharmarajan, Arun M.

    2013-01-01

    Highlights: •Expression profile of Wnt pathway related genes in mesothelioma cells. •Differential expression of key Wnt pathway molecules and regulators. •Wnt3a stimulated mesothelioma growth whereas sFRP4 was inhibitory. •Targeting β-Catenin can sensitise mesothelioma cells to cytotoxic drugs. -- Abstract: Malignant mesothelioma (MM) is an uncommon and particularly aggressive cancer associated with asbestos exposure, which currently presents an intractable clinical challenge. Wnt signaling has been reported to play a role in the neoplastic properties of mesothelioma cells but has not been investigated in detail in this cancer. We surveyed expression of Wnts, their receptors, and other key molecules in this pathway in well established in vitro mesothelioma models in comparison with primary mesothelial cultures. We also tested the biological response of MM cell lines to exogenous Wnt and secreted regulators, as well as targeting β-catenin. We detected frequent expression of Wnt3 and Wnt5a, as well as Fzd 2, 4 and 6. The mRNA of Wnt4, Fzd3, sFRP4, APC and axin2 were downregulated in MM relative to mesothelial cells while LEF1 was overexpressed in MM. Functionally, we observed that Wnt3a stimulated MM proliferation while sFRP4 was inhibitory. Furthermore, directly targeting β-catenin expression could sensitise MM cells to cytotoxic drugs. These results provide evidence for altered expression of a number of Wnt/Fzd signaling molecules in MM. Modulation of Wnt signaling in MM may prove a means of targeting proliferation and drug resistance in this cancer

  15. Wnt5a is associated with cigarette smoke-related lung carcinogenesis via protein kinase C.

    Science.gov (United States)

    Whang, Young Mi; Jo, Ukhyun; Sung, Jae Sook; Ju, Hyun Jung; Kim, Hyun Kyung; Park, Kyong Hwa; Lee, Jong Won; Koh, In Song; Kim, Yeul Hong

    2013-01-01

    Wnt5a is overexpressed during the progression of human non-small cell lung cancer. However, the roles of Wnt5a during smoking-related lung carcinogenesis have not been clearly elucidated. We investigated the associations between Wnt5a and the early development of cigarette smoke related lung cancer using human bronchial epithelial (HBE) cells (NHBE, BEAS-2B, 1799, 1198 and 1170I) at different malignant stages established by exposure to cigarette smoke condensate (CSC). Abnormal up-regulation of Wnt5a mRNA and proteins was detected in CSC-exposed transformed 1198 and tumorigenic 1170I cells as compared with other non-CSC exposed HBE cells. Tumor tissues obtained from smokers showed higher Wnt5a expressions than matched normal tissues. In non-CSC exposed 1799 cells, treatment of recombinant Wnt5a caused the activations of PKC and Akt, and the blockage of Wnt5a and PKC significantly decreased the viabilities of CSC-transformed 1198 cells expressing high levels of Wnt5a. This reduced cell survival rate was associated with increased apoptosis via the down-regulation of Bcl2 and the induction of cleaved poly ADP-ribose polymerase. Moreover, CSC-treated 1799 cells showed induction of Wnt5a expression and enhanced colony-forming capacity. The CSC-induced colony forming efficiency was suppressed by the co-incubation with a PKC inhibitor. In conclusion, these results suggest that cigarette smoke induces Wnt5a-coupled PKC activity during lung carcinogenesis, which causes Akt activity and anti-apoptosis in lung cancer. Therefore, current study provides novel clues for the crucial role of Wnt5a in the smoking-related lung carcinogenesis.

  16. Wnt5a is associated with cigarette smoke-related lung carcinogenesis via protein kinase C.

    Directory of Open Access Journals (Sweden)

    Young Mi Whang

    Full Text Available Wnt5a is overexpressed during the progression of human non-small cell lung cancer. However, the roles of Wnt5a during smoking-related lung carcinogenesis have not been clearly elucidated. We investigated the associations between Wnt5a and the early development of cigarette smoke related lung cancer using human bronchial epithelial (HBE cells (NHBE, BEAS-2B, 1799, 1198 and 1170I at different malignant stages established by exposure to cigarette smoke condensate (CSC. Abnormal up-regulation of Wnt5a mRNA and proteins was detected in CSC-exposed transformed 1198 and tumorigenic 1170I cells as compared with other non-CSC exposed HBE cells. Tumor tissues obtained from smokers showed higher Wnt5a expressions than matched normal tissues. In non-CSC exposed 1799 cells, treatment of recombinant Wnt5a caused the activations of PKC and Akt, and the blockage of Wnt5a and PKC significantly decreased the viabilities of CSC-transformed 1198 cells expressing high levels of Wnt5a. This reduced cell survival rate was associated with increased apoptosis via the down-regulation of Bcl2 and the induction of cleaved poly ADP-ribose polymerase. Moreover, CSC-treated 1799 cells showed induction of Wnt5a expression and enhanced colony-forming capacity. The CSC-induced colony forming efficiency was suppressed by the co-incubation with a PKC inhibitor. In conclusion, these results suggest that cigarette smoke induces Wnt5a-coupled PKC activity during lung carcinogenesis, which causes Akt activity and anti-apoptosis in lung cancer. Therefore, current study provides novel clues for the crucial role of Wnt5a in the smoking-related lung carcinogenesis.

  17. A growing field: The regulation of axonal regeneration by Wnt signaling.

    Science.gov (United States)

    Garcia, Armando L; Udeh, Adanna; Kalahasty, Karthik; Hackam, Abigail S

    2018-01-01

    The canonical Wnt/β-catenin pathway is a highly conserved signaling cascade that plays critical roles during embryogenesis. Wnt ligands regulate axonal extension, growth cone guidance and synaptogenesis throughout the developing central nervous system (CNS). Recently, studies in mammalian and fish model systems have demonstrated that Wnt/β-catenin signaling also promotes axonal regeneration in the adult optic nerve and spinal cord after injury, raising the possibility that Wnt could be developed as a therapeutic strategy. In this review, we summarize experimental evidence that reveals novel roles for Wnt signaling in the injured CNS, and discuss possible mechanisms by which Wnt ligands could overcome molecular barriers inhibiting axonal growth to promote regeneration. A central challenge in the neuroscience field is developing therapeutic strategies that induce robust axonal regeneration. Although adult axons have the capacity to respond to axonal guidance molecules after injury, there are several major obstacles for axonal growth, including extensive neuronal death, glial scars at the injury site, and lack of axonal guidance signals. Research in rodents demonstrated that activation of Wnt/β-catenin signaling in retinal neurons and radial glia induced neuronal survival and axonal growth, but that activation within reactive glia at the injury site promoted proliferation and glial scar formation. Studies in zebrafish spinal cord injury models confirm an axonal regenerative role for Wnt/β-catenin signaling and identified the cell types responsible. Additionally, in vitro and in vivo studies demonstrated that Wnt induces axonal and neurite growth through transcription-dependent effects of its central mediator β-catenin, potentially by inducing regeneration-promoting genes. Canonical Wnt signaling may also function through transcription-independent interactions of β-catenin with cytoskeletal elements, which could stabilize growing axons and control growth cone

  18. The Wnt Signaling Landscape of Mammary Stem Cells and Breast Tumors.

    Science.gov (United States)

    Alexander, Caroline M

    2018-01-01

    Attention has been focused on Wnt signaling in the mouse mammary gland for several decades, firstly by the discovery of several Wnt loci among the oncogenes revealed by MMTV-based insertional mutagenesis screening of mouse mammary gland, and then by the remarkable visualization of Wnt-dependent specification of mammary placodes in embryonic skin. This review aims to summarize the impact of recent data for our understanding of the roles of Wnt signaling in these roles. The amount and identity of both familiar and novel Wnt signaling components is examined for mouse mammary epithelial cells. The hierarchical arrangement of mammary epithelial cell progenitors and stem cells inferred from the study of isolated cells is reinterpreted in an era that has demonstrated almost limitless cellular plasticity. Functional definitions of stem and progenitor activities are reevaluated with the discovery of novel stem cell activities and regulators, and we draw parallels with the arrangement of replication-competent cells in other tissues. Although Wnt signaling is highly oncogenic for mouse mammary epithelia, the data supporting Wnt signaling as a tumor driver for human breast cancer are still flimsy, and there is little support for the recruitment of normal Wnt-dependent breast stem cells as tumor precursor cells for either mouse or human. We discuss possible explanations for this paradox and questions still unanswered, including the potential impact of recent discoveries of Wnt-secreting microenvironments, oncogenic changes in the Rspo/Lgr/Ubiquitin ligase amplifier complex, as they could apply to breast tissues, and the feedback suppression of Wnt signaling that characterizes its developmental activity and may hide Wnt signatures in tumors. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Activation of Wnt Signaling in Cortical Neurons Enhances Glucose Utilization through Glycolysis.

    Science.gov (United States)

    Cisternas, Pedro; Salazar, Paulina; Silva-Álvarez, Carmen; Barros, L Felipe; Inestrosa, Nibaldo C

    2016-12-09

    The Wnt signaling pathway is critical for a number of functions in the central nervous system, including regulation of the synaptic cleft structure and neuroprotection against injury. Deregulation of Wnt signaling has been associated with several brain pathologies, including Alzheimer's disease. In recent years, it has been suggested that the Wnt pathway might act as a central integrator of metabolic signals from peripheral organs to the brain, which would represent a new role for Wnt signaling in cell metabolism. Energy metabolism is critical for normal neuronal function, which mainly depends on glucose utilization. Brain energy metabolism is important in almost all neurological disorders, to which a decrease in the capacity of the brain to utilize glucose has been linked. However, little is known about the relationship between Wnt signaling and neuronal glucose metabolism in the cellular context. In the present study, we found that acute treatment with the Wnt3a ligand induced a large increase in glucose uptake, without changes in the expression or localization of glucose transporter type 3. In addition, we observed that Wnt3a treatment increased the activation of the metabolic sensor Akt. Moreover, we observed an increase in the activity of hexokinase and in the glycolytic rate, and both processes were dependent on activation of the Akt pathway. Furthermore, we did not observe changes in the activity of glucose-6-phosphate dehydrogenase or in the pentose phosphate pathway. The effect of Wnt3a was independent of both the transcription of Wnt target genes and synaptic effects of Wnt3a. Together, our results suggest that Wnt signaling stimulates glucose utilization in cortical neurons through glycolysis to satisfy the high energy demand of these cells. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Expression profile and function of Wnt signaling mechanisms in malignant mesothelioma cells

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Simon A., E-mail: s.fox@curtin.edu.au [Molecular Pharmacology Laboratory, School of Pharmacy, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA (Australia); Richards, Alex K.; Kusumah, Ivonne; Perumal, Vanathi [Molecular Pharmacology Laboratory, School of Pharmacy, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA (Australia); Bolitho, Erin M. [Western Australian Institute for Medical Research, The University of Western Australia Centre for Medical Research, Perth, WA (Australia); Mutsaers, Steven E. [Lung Institute of Western Australia, Centre for Asthma Allergy and Respiratory Research, University of Western Australia, Nedlands (Australia); Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, University of Western Australia and Western Australian Institute for Medical Research, Nedlands (Australia); Dharmarajan, Arun M. [School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA (Australia)

    2013-10-11

    Highlights: •Expression profile of Wnt pathway related genes in mesothelioma cells. •Differential expression of key Wnt pathway molecules and regulators. •Wnt3a stimulated mesothelioma growth whereas sFRP4 was inhibitory. •Targeting β-Catenin can sensitise mesothelioma cells to cytotoxic drugs. -- Abstract: Malignant mesothelioma (MM) is an uncommon and particularly aggressive cancer associated with asbestos exposure, which currently presents an intractable clinical challenge. Wnt signaling has been reported to play a role in the neoplastic properties of mesothelioma cells but has not been investigated in detail in this cancer. We surveyed expression of Wnts, their receptors, and other key molecules in this pathway in well established in vitro mesothelioma models in comparison with primary mesothelial cultures. We also tested the biological response of MM cell lines to exogenous Wnt and secreted regulators, as well as targeting β-catenin. We detected frequent expression of Wnt3 and Wnt5a, as well as Fzd 2, 4 and 6. The mRNA of Wnt4, Fzd3, sFRP4, APC and axin2 were downregulated in MM relative to mesothelial cells while LEF1 was overexpressed in MM. Functionally, we observed that Wnt3a stimulated MM proliferation while sFRP4 was inhibitory. Furthermore, directly targeting β-catenin expression could sensitise MM cells to cytotoxic drugs. These results provide evidence for altered expression of a number of Wnt/Fzd signaling molecules in MM. Modulation of Wnt signaling in MM may prove a means of targeting proliferation and drug resistance in this cancer.

  1. Homogeneous bilateral block shifts

    Indian Academy of Sciences (India)

    Douglas class were classified in [3]; they are unilateral block shifts of arbitrary block size (i.e. dim H(n) can be anything). However, no examples of irreducible homogeneous bilateral block shifts of block size larger than 1 were known until now.

  2. Frizzled-8 receptor is activated by the Wnt-2 ligand in non-small cell lung cancer

    International Nuclear Information System (INIS)

    Bravo, Dawn T; Yang, Yi-Lin; Kuchenbecker, Kristopher; Hung, Ming-Szu; Xu, Zhidong; Jablons, David M; You, Liang

    2013-01-01

    Wnt-2 plays an oncogenic role in cancer, but which Frizzled receptor(s) mediates the Wnt-2 signaling pathway in lung cancer remains unclear. We sought to (1) identify and evaluate the activation of Wnt-2 signaling through Frizzled-8 in non-small cell lung cancer, and (2) test whether a novel expression construct dominant negative Wnt-2 (dnhWnt-2) reduces tumor growth in a colony formation assay and in a xenograft mouse model. Semi-quantitative RT-PCR was used to identify the expression of Wnt-2 and Frizzled-8 in 50 lung cancer tissues from patients. The TCF reporter assay (TOP/FOP) was used to detect the activation of the Wnt canonical pathway in vitro. A novel dnhWnt-2 construct was designed and used to inhibit activation of Wnt-2 signaling through Frizzled-8 in 293T, 293, A549 and A427 cells and in a xenograft mouse model. Statistical comparisons were made using Student’s t-test. Among the 50 lung cancer samples, we identified a 91% correlation between the transcriptional increase of Wnt-2 and Frizzled-8 (p<0.05). The Wnt canonical pathway was activated when both Wnt-2 and Frizzled-8 were co-expressed in 293T, 293, A549 and A427 cells. The dnhWnt-2 construct we used inhibited the activation of Wnt-2 signaling in 293T, 293, A549 and A427 cells, and reduced the colony formation of NSCLC cells when β-catenin was present (p<0.05). Inhibition of Wnt-2 activation by the dnhWnt-2 construct further reduced the size and mass of tumors in the xenograft mouse model (p<0.05). The inhibition also decreased the expression of target genes of Wnt signaling in these tumors. We demonstrated an activation of Wnt-2 signaling via the Frizzled-8 receptor in NSCLC cells. A novel dnhWnt-2 construct significantly inhibits Wnt-2 signaling, reduces colony formation of NSCLC cells in vitro and tumor growth in a xenograft mouse model. The dnhWnt-2 construct may provide a new therapeutic avenue for targeting the Wnt pathway in lung cancer

  3. Expression of hypoxia-inducible factor-1 by trophectoderm cells in response to hypoxia and epidermal growth factor

    International Nuclear Information System (INIS)

    Jeong, Wooyoung; Bazer, Fuller W.; Song, Gwonhwa; Kim, Jinyoung

    2016-01-01

    The low oxygen environment in the uterine environment requires pre-implantation embryos to adapt to oxygen deficiency. Hypoxia-inducible factor (HIF)-1 is a master regulator whereby cells adapt to changes in oxygen concentrations. In addition to hypoxic conditions, non-hypoxic stimuli such as growth factors also activate expression of HIF-1. In this study, the mechanisms underlying low oxygen-dependent and epidermal growth factor (EGF)-dependent expression of HIF-1α were explored using porcine trophectoderm (pTr) cells. The results indicated that expression of HIF-1α and HIF-1β mRNAs was not affected by low concentrations of oxygen; however, hypoxic conditions markedly increased the abundance of HIF-1α protein, especially in nuclei of pTr cells. Even under normoxic conditions, the abundance of HIF-1α protein increased in response to EGF. This EGF-mediated increase in HIF-1α protein was blocked through inhibition of translation by cycloheximide. The inhibitors LY294002 (PI3K-AKT inhibitor), U0126 (inhibitor of ERK1/2) and rapamycin (mTOR inhibitor) also blocked the ability of EGF to increase HIF-1α protein and to phosphorylate AKT, ERK1/2 and mTOR proteins. Both hypoxia and EGF induced proliferation of pTr cells. This ability of EGF to stimulate proliferation of pTr cells was suppressed by EGFR siRNA, but not HIF-1α siRNA, but a significant decrease in EGF-induced HIF-1α protein occurred when pTr cells were transfected with HIF-1α siRNA. The results of the present study suggest that pTr cells adapt to oxygen deficiency and proliferate in response to an oxygen-dependent HIF-1 system, and that EGF at maternal–conceptus interface can increase the abundance of HIF-1α protein via translational regulation through AKT, ERK1/2 and mTOR signaling cascades. - Highlights: • HIF-1α expression is up-regulated in pTr cells under low oxygen concentrations. • EGF induces HIF-1α accumulation in pTr cells. • EGF-induced HIF-1α accumulation is blocked by de

  4. Expression of hypoxia-inducible factor-1 by trophectoderm cells in response to hypoxia and epidermal growth factor

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Wooyoung [Department of Animal Resources Science, Dankook University, Cheonan (Korea, Republic of); Bazer, Fuller W. [Center for Animal Biotechnology and Genomics and Department of Animal Science, Texas A& M University, College Station, TX (United States); Song, Gwonhwa, E-mail: ghsong@korea.ac.kr [Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul (Korea, Republic of); Kim, Jinyoung, E-mail: jinyoungkim@dankook.ac.kr [Department of Animal Resources Science, Dankook University, Cheonan (Korea, Republic of)

    2016-01-08

    The low oxygen environment in the uterine environment requires pre-implantation embryos to adapt to oxygen deficiency. Hypoxia-inducible factor (HIF)-1 is a master regulator whereby cells adapt to changes in oxygen concentrations. In addition to hypoxic conditions, non-hypoxic stimuli such as growth factors also activate expression of HIF-1. In this study, the mechanisms underlying low oxygen-dependent and epidermal growth factor (EGF)-dependent expression of HIF-1α were explored using porcine trophectoderm (pTr) cells. The results indicated that expression of HIF-1α and HIF-1β mRNAs was not affected by low concentrations of oxygen; however, hypoxic conditions markedly increased the abundance of HIF-1α protein, especially in nuclei of pTr cells. Even under normoxic conditions, the abundance of HIF-1α protein increased in response to EGF. This EGF-mediated increase in HIF-1α protein was blocked through inhibition of translation by cycloheximide. The inhibitors LY294002 (PI3K-AKT inhibitor), U0126 (inhibitor of ERK1/2) and rapamycin (mTOR inhibitor) also blocked the ability of EGF to increase HIF-1α protein and to phosphorylate AKT, ERK1/2 and mTOR proteins. Both hypoxia and EGF induced proliferation of pTr cells. This ability of EGF to stimulate proliferation of pTr cells was suppressed by EGFR siRNA, but not HIF-1α siRNA, but a significant decrease in EGF-induced HIF-1α protein occurred when pTr cells were transfected with HIF-1α siRNA. The results of the present study suggest that pTr cells adapt to oxygen deficiency and proliferate in response to an oxygen-dependent HIF-1 system, and that EGF at maternal–conceptus interface can increase the abundance of HIF-1α protein via translational regulation through AKT, ERK1/2 and mTOR signaling cascades. - Highlights: • HIF-1α expression is up-regulated in pTr cells under low oxygen concentrations. • EGF induces HIF-1α accumulation in pTr cells. • EGF-induced HIF-1α accumulation is blocked by de

  5. Cellular prion protein (PrPc and hypoxia: true to each other in good times and in bad, in sickness and in health

    Directory of Open Access Journals (Sweden)

    Sanja Ramljak

    2016-12-01

    Full Text Available The cellular prion protein (PrPc and hypoxia appear to be tightly intertwined. Beneficial effects of PrPc on neuronal survival under hypoxic conditions such as focal cerebral ischemia are strongly supported. Conversely, increasing evidence indicates detrimental effects of increased PrPc expression on cancer progression, another condition accompanied by low oxygen tensions. A switch between anaerobic and aerobic metabolism characterizes both conditions. A cellular process that might unite both is glycolysis. Putative role of PrPc in stimulation of glycolysis in times of need is indeed thought provoking. A significance of astrocytic PrPc expression for neuronal survival under hypoxic conditions and possible association of PrPc with the astrocyte-neuron lactate shuttle (ANLS is considered. We posit PrPc-induced lactate production via transactivation of lactate dehydrogenase A by hypoxia inducible factor 1α as an important factor for survival of both neurons and tumor cells in hypoxic microenvironment. Concomitantly, we discuss a cross-talk between Wnt/ß-catenin and PI-3K/Akt signaling pathways in executing PrPc-induced activation of glycolysis. Finally, we would like to emphasize that we see a great potential in joining expertise from both fields, neuroscience and cancer research in revealing the mechanisms underlying hypoxia-related pathologies. PrPc may prove focal point for future research.

  6. URG11 mediates hypoxia-induced epithelial-to-mesenchymal transition by modulation of E-cadherin and β-catenin

    International Nuclear Information System (INIS)

    Du, Rui; Huang, Chen; Bi, Qian; Zhai, Ying; Xia, Lin; Liu, Jie; Sun, Shiren; Fan, Daiming

    2010-01-01

    Upregulated gene 11 (URG11), recently identified as a new HBx-upregulated gene that may activate β-catenin and Wnt signaling, was found to be upregulated in a human tubule cell line under low oxygen. Here, we investigated the potential role of URG11 in hypoxia-induced renal tubular epithelial-to-mesenchymal (EMT). Overexpression of URG11 in a human proximal tubule cell line (HK2) promoted a mesenchymal phenotype accompanied by reduced expression of the epithelial marker E-cadherin and increased expression of the mesenchymal markers vimentin and α-SMA, while URG11 knockdown by siRNA effectively reversed hypoxia-induced EMT. URG11 promoted the expression of β-catenin and increased its nuclear accumulation under normoxic conditions through transactivation of the β-catenin promoter. This in turn upregulated β-catenin/T-cell factor (TCF) and its downstream effector genes, vimentin, and α-SMA. In vivo, strong expression of URG11 was observed in the tubular epithelia of 5/6-nephrectomized rats, and a Western blot analysis demonstrated a close correlation between HIF-1α and URG11 protein levels. Altogether, our results indicate that URG11 mediates hypoxia-induced EMT through the suppression of E-cadherin and the activation of the β-catenin/TCF pathway.

  7. Secreted Frizzled-related protein-2 (sFRP2) augments canonical Wnt3a-induced signaling

    Energy Technology Data Exchange (ETDEWEB)

    Marschall, Zofia von [Craniofacial and Skeletal Diseases Branch, NIDCR, NIH, DHHS, Bethesda, MD (United States); Fisher, Larry W., E-mail: lfisher@dir.nidcr.nih.gov [Craniofacial and Skeletal Diseases Branch, NIDCR, NIH, DHHS, Bethesda, MD (United States)

    2010-09-24

    Research highlights: {yields} sFRP2 enhances the Wnt3a-induced {beta}-catenin stabilization and its nuclear translocation. {yields} sFRP2 enhances LRP6 phosphorylation and Wnt3a/{beta}-catenin transcriptional reporter activity. {yields} Dickkopf-1 (DKK1) fully antagonizes both Wnt3a/sFRP2-induced LRP6 phosphorylation and transcriptional activity. {yields} sFRP2 enhances expression of genes known to be regulated by Wnt3a signaling. -- Abstract: Secreted Frizzled-related proteins (sFRP) are involved in embryonic development as well as pathological conditions including bone and myocardial disorders and cancer. Because of their sequence homology with the Wnt-binding domain of Frizzled, they have generally been considered antagonists of canonical Wnt signaling. However, additional activities of various sFRPs including both synergism and mimicry of Wnt signaling as well as functions other than modulation of Wnt signaling have been reported. Using human embryonic kidney cells (HEK293A), we found that sFRP2 enhanced Wnt3a-dependent phosphorylation of LRP6 as well as both cytosolic {beta}-catenin levels and its nuclear translocation. While addition of recombinant sFRP2 had no activity by itself, Top/Fop luciferase reporter assays showed a dose-dependent increase of Wnt3a-mediated transcriptional activity. sFRP2 enhancement of Wnt3a signaling was abolished by treatment with the Wnt antagonist, Dickkopf-1 (DKK1). Wnt-signaling pathway qPCR arrays showed that sFRP2 enhanced the Wnt3a-mediated transcriptional up-regulation of several genes regulated by Wnt3a including its antagonists, DKK1, and Naked cuticle-1 homolog (NKD1). These results support sFRP2's role as an enhancer of Wnt/{beta}-catenin signaling, a result with biological impact for both normal development and diverse pathologies such as tumorigenesis.

  8. Secreted Frizzled-related protein-2 (sFRP2) augments canonical Wnt3a-induced signaling

    International Nuclear Information System (INIS)

    Marschall, Zofia von; Fisher, Larry W.

    2010-01-01

    Research highlights: → sFRP2 enhances the Wnt3a-induced β-catenin stabilization and its nuclear translocation. → sFRP2 enhances LRP6 phosphorylation and Wnt3a/β-catenin transcriptional reporter activity. → Dickkopf-1 (DKK1) fully antagonizes both Wnt3a/sFRP2-induced LRP6 phosphorylation and transcriptional activity. → sFRP2 enhances expression of genes known to be regulated by Wnt3a signaling. -- Abstract: Secreted Frizzled-related proteins (sFRP) are involved in embryonic development as well as pathological conditions including bone and myocardial disorders and cancer. Because of their sequence homology with the Wnt-binding domain of Frizzled, they have generally been considered antagonists of canonical Wnt signaling. However, additional activities of various sFRPs including both synergism and mimicry of Wnt signaling as well as functions other than modulation of Wnt signaling have been reported. Using human embryonic kidney cells (HEK293A), we found that sFRP2 enhanced Wnt3a-dependent phosphorylation of LRP6 as well as both cytosolic β-catenin levels and its nuclear translocation. While addition of recombinant sFRP2 had no activity by itself, Top/Fop luciferase reporter assays showed a dose-dependent increase of Wnt3a-mediated transcriptional activity. sFRP2 enhancement of Wnt3a signaling was abolished by treatment with the Wnt antagonist, Dickkopf-1 (DKK1). Wnt-signaling pathway qPCR arrays showed that sFRP2 enhanced the Wnt3a-mediated transcriptional up-regulation of several genes regulated by Wnt3a including its antagonists, DKK1, and Naked cuticle-1 homolog (NKD1). These results support sFRP2's role as an enhancer of Wnt/β-catenin signaling, a result with biological impact for both normal development and diverse pathologies such as tumorigenesis.

  9. Role of hypoxia and hypoxia inducible factor in physiological and pathological conditions

    Directory of Open Access Journals (Sweden)

    Mozhgan Jahani

    2017-11-01

    Full Text Available Introduction: Organisms are exposed to oxygen deprivation (Hypoxia in various physiological and pathological conditions. There are different conserve evolutionary responses to counterview with this stress that primary transcriptional response to stress related to hypoxia is interceded by hypoxia-inducible factor (HIF-1 in mammals. This factor can regulate different genes that have essential roles in adaptation to this condition. In this review, the role of this factor in physiological and pathological conditions under hypoxic condition has been evaluated after examining structural features and regulation characteristics of HIF-1. Methods: First, articles related to the keywords of hypoxia and HIF-1 (from 1991-2016 were searched from valid databases such as Springer Link, Google Scholar, PubMed and Science direct. Then, the articles correlated with hypoxia, HIF-1 and their roles in physiological and pathological conditions (120 articles were searched and just 64 articles were selected for this study. Result: According to studies, there are different genes in cells and organs that can be regulated by HIF-1. Activation of genes expression by this protein occurs through its linkage to cis-acting of 50 base pair hypoxia response element (HRE region located in their promotor and enhancer. Depending on circumstances, activation of these genes can be beneficial or harmful. Conclusion: Activation of different genes in hypoxia by HIF-1 has different effects on physiological and pathological conditions. Therefore, HIF-1, as a hypoxia-inducible factor in hypoxic conditions, plays an essential role in the adaptation of cells and organs to changes related to the presence of oxygen.

  10. Frequently asked questions in hypoxia research

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    Wenger RH

    2015-09-01

    Full Text Available Roland H Wenger,1,2 Vartan Kurtcuoglu,1,2 Carsten C Scholz,1,2 Hugo H Marti,3 David Hoogewijs1,2,4 1Institute of Physiology and Zurich Center for Human Physiology (ZIHP, University of Zurich, 2National Center of Competence in Research “Kidney.CH”, Zurich, Switzerland; 3Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, 4Institute of Physiology, University of Duisburg-Essen, Essen, Germany Abstract: “What is the O2 concentration in a normoxic cell culture incubator?” This and other frequently asked questions in hypoxia research will be answered in this review. Our intention is to give a simple introduction to the physics of gases that would be helpful for newcomers to the field of hypoxia research. We will provide background knowledge about questions often asked, but without straightforward answers. What is O2 concentration, and what is O2 partial pressure? What is normoxia, and what is hypoxia? How much O2 is experienced by a cell residing in a culture dish in vitro vs in a tissue in vivo? By the way, the O2 concentration in a normoxic incubator is 18.6%, rather than 20.9% or 20%, as commonly stated in research publications. And this is strictly only valid for incubators at sea level. Keywords: gas laws, hypoxia-inducible factor, Krogh tissue cylinder, oxygen diffusion, partial pressure, tissue oxygen levels

  11. Hypoxanthine as a measurement of hypoxia.

    Science.gov (United States)

    Saugstad, O D

    1975-04-01

    The hypoxanthine concentration in plasma was found to be a sensitive parameter of hypoxia of the fetus and the newborn infant. The plasma level of hypoxanthine in the umbilical cord in 29 newborn infants with normal delivery varied between 0 and 11.0 mumol/liter with a mean of 5.8 mumol/liter, SD 3.0 mumol/liter. Compared with this reference group the hypoxanthine concentration in plasma of the umbilical cord in 10 newborn infants with clinical signs of intrauterine hypoxia during labor was found to be significantly higher, with a range of 11.0-61.5 mumol/liter, with a mean of 25.0 mumol/liter, SD 18.0 mumol/liter. The plasma level of hypoxanthine in two premature babies developing an idiopathic respiratory distress syndrome was monitored. The metabolite was found to be considerably increased, in one of them more than 24 hr after a period of hypoxia necessitating artificial ventilation. The hypoxanthine level in plasma of umbilical arterial blood was followed about 2 hr postpartum in three newborn infants with clinical signs of intrauterine hypoxia. The decrease of the plasma concentration of the metabolite seemed to be with a constant velocity, as it was about 10 mumol/liter/hr in these cases. A new method was used for the determination of hypoxanthine in plasma, based on the principle that PO2 decreased when hypoxanthine is oxidized to uric acid.

  12. Hypoxia and Angiogenesis in Endometrioid Endometrial Carcinogenesis

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    Nicole Horrée

    2007-01-01

    Full Text Available Background: Hypoxia-inducible factor 1α (HIF-1α plays an essential role in the adaptive response of cells to hypoxia, triggering biologic events associated with aggressive tumor behavior. Methods: Expression of HIF-1α and proteins in the HIF-1α pathway (Glut-1, CAIX, VEGF in paraffin-embedded specimens of normal (n = 17, premalignant (n = 17 and endometrioid endometrial carcinoma (n = 39 was explored by immunohistochemistry, in relation to microvessel density (MVD. Results: HIF-1α overexpression was absent in inactive endometrium but present in hyperplasia (61% and carcinoma (87%, with increasing expression in a perinecrotic fashion pointing to underlying hypoxia. No membranous expression of Glut-1 and CAIX was noticed in inactive endometrium, in contrast with expression in hyperplasia (Glut-1 0%, CAIX 61%, only focal and diffuse and carcinoma (Glut-1 94.6%, CAIX 92%, both mostly perinecrotically. Diffuse HIF-1α was accompanied by activation of downstream targets. VEGF was significantly higher expressed in hyperplasias and carcinomas compared to inactive endometrium. MVD was higher in hyperplasias and carcinomas than in normal endometrium (p < 0.001. Conclusion: HIF-1α and its downstream genes are increasingly expressed from normal through premalignant to endometrioid adenocarcinoma of the endometrium, paralleled by activation of its downstream genes and increased angiogenesis. This underlines the potential importance of hypoxia and its key regulator HIF-1α in endometrial carcinogenesis.

  13. Signaling hypoxia by hypoxia-inducible factor protein hydroxylases: a historical overview and future perspectives

    Science.gov (United States)

    Bishop, Tammie; Ratcliffe, Peter J

    2014-01-01

    By the early 1900s, the close matching of oxygen supply with demand was recognized to be a fundamental requirement for physiological function, and multiple adaptive responses to environment hypoxia had been described. Nevertheless, the widespread operation of mechanisms that directly sense and respond to levels of oxygen in animal cells was not appreciated for most of the twentieth century with investigators generally stressing the regulatory importance of metabolic products. Work over the last 25 years has overturned that paradigm. It has revealed the existence of a set of “oxygen-sensing” 2-oxoglutarate dependent dioxygenases that catalyze the hydroxylation of specific amino acid residues and thereby control the stability and activity of hypoxia-inducible factor. The hypoxia-inducible factor hydroxylase pathway regulates a massive transcriptional cascade that is operative in essentially all animal cells. It transduces a wide range of responses to hypoxia, extending well beyond the classical boundaries of hypoxia physiology. Here we review the discovery and elucidation of these pathways, and consider the opportunities and challenges that have been brought into focus by the findings, including new implications for the integrated physiology of hypoxia and therapeutic approaches to ischemic/hypoxic disease. PMID:27774477

  14. Hepcidin: A Critical Regulator of Iron Metabolism during Hypoxia

    Directory of Open Access Journals (Sweden)

    Korry J. Hintze

    2011-01-01

    Full Text Available Iron status affects cognitive and physical performance in humans. Recent evidence indicates that iron balance is a tightly regulated process affected by a series of factors other than diet, to include hypoxia. Hypoxia has profound effects on iron absorption and results in increased iron acquisition and erythropoiesis when humans move from sea level to altitude. The effects of hypoxia on iron balance have been attributed to hepcidin, a central regulator of iron homeostasis. This paper will focus on the molecular mechanisms by which hypoxia affects hepcidin expression, to include a review of the hypoxia inducible factor (HIF/hypoxia response element (HRE system, as well as recent evidence indicating that localized adipose hypoxia due to obesity may affect hepcidin signaling and organismal iron metabolism.

  15. Wnt/β-catenin signaling changes C2C12 myoblast proliferation and differentiation by inducing Id3 expression

    International Nuclear Information System (INIS)

    Zhang, Long; Shi, Songting; Zhang, Juan; Zhou, Fangfang; Dijke, Peter ten

    2012-01-01

    Highlights: ► Expression of Id3 but not Id1 is induced by Wnt3a stimulation in C2C12 cells. ► Wnt3a induces Id3 expression via canonical Wnt/β-catenin pathway. ► Wnt3a-induced Id3 expression does not depend on BMP signaling activation. ► Induction of Id3 expression is critical determinant in Wnt3a-induced cell proliferation and differentiation. -- Abstract: Canonical Wnt signaling plays important roles in regulating cell proliferation and differentiation. In this study, we report that inhibitor of differentiation (Id)3 is a Wnt-inducible gene in mouse C2C12 myoblasts. Wnt3a induced Id3 expression in a β-catenin-dependent manner. Bone morphogenetic protein (BMP) also potently induced Id3 expression. However, Wnt-induced Id3 expression occurred independent of the BMP/Smad pathway. Functional studies showed that Id3 depletion in C2C12 cells impaired Wnt3a-induced cell proliferation and alkaline phosphatase activity, an early marker of osteoblast cells. Id3 depletion elevated myogenin induction during myogenic differentiation and partially impaired Wnt3a suppressed myogenin expression in C2C12 cells. These results suggest that Id3 is an important Wnt/β-catenin induced gene in myoblast cell fate determination.

  16. Wnt-5a/Frizzled9 Receptor Signaling through the Gαo-Gβγ Complex Regulates Dendritic Spine Formation*

    Science.gov (United States)

    Ramírez, Valerie T.; Ramos-Fernández, Eva; Henríquez, Juan Pablo; Lorenzo, Alfredo; Inestrosa, Nibaldo C.

    2016-01-01

    Wnt ligands play crucial roles in the development and regulation of synapse structure and function. Specifically, Wnt-5a acts as a secreted growth factor that regulates dendritic spine formation in rodent hippocampal neurons, resulting in postsynaptic development that promotes the clustering of the PSD-95 (postsynaptic density protein 95). Here, we focused on the early events occurring after the interaction between Wnt-5a and its Frizzled receptor at the neuronal cell surface. Additionally, we studied the role of heterotrimeric G proteins in Wnt-5a-dependent synaptic development. We report that FZD9 (Frizzled9), a Wnt receptor related to Williams syndrome, is localized in the postsynaptic region, where it interacts with Wnt-5a. Functionally, FZD9 is required for the Wnt-5a-mediated increase in dendritic spine density. FZD9 forms a precoupled complex with Gαo under basal conditions that dissociates after Wnt-5a stimulation. Accordingly, we found that G protein inhibition abrogates the Wnt-5a-dependent pathway in hippocampal neurons. In particular, the activation of Gαo appears to be a key factor controlling the Wnt-5a-induced dendritic spine density. In addition, we found that Gβγ is required for the Wnt-5a-mediated increase in cytosolic calcium levels and spinogenesis. Our findings reveal that FZD9 and heterotrimeric G proteins regulate Wnt-5a signaling and dendritic spines in cultured hippocampal neurons. PMID:27402827

  17. Testing block subdivision algorithms on block designs

    Science.gov (United States)

    Wiseman, Natalie; Patterson, Zachary

    2016-01-01

    Integrated land use-transportation models predict future transportation demand taking into account how households and firms arrange themselves partly as a function of the transportation system. Recent integrated models require parcels as inputs and produce household and employment predictions at the parcel scale. Block subdivision algorithms automatically generate parcel patterns within blocks. Evaluating block subdivision algorithms is done by way of generating parcels and comparing them to those in a parcel database. Three block subdivision algorithms are evaluated on how closely they reproduce parcels of different block types found in a parcel database from Montreal, Canada. While the authors who developed each of the algorithms have evaluated them, they have used their own metrics and block types to evaluate their own algorithms. This makes it difficult to compare their strengths and weaknesses. The contribution of this paper is in resolving this difficulty with the aim of finding a better algorithm suited to subdividing each block type. The proposed hypothesis is that given the different approaches that block subdivision algorithms take, it's likely that different algorithms are better adapted to subdividing different block types. To test this, a standardized block type classification is used that consists of mutually exclusive and comprehensive categories. A statistical method is used for finding a better algorithm and the probability it will perform well for a given block type. Results suggest the oriented bounding box algorithm performs better for warped non-uniform sites, as well as gridiron and fragmented uniform sites. It also produces more similar parcel areas and widths. The Generalized Parcel Divider 1 algorithm performs better for gridiron non-uniform sites. The Straight Skeleton algorithm performs better for loop and lollipop networks as well as fragmented non-uniform and warped uniform sites. It also produces more similar parcel shapes and patterns.

  18. Pimonidazole: a novel hypoxia marker for complementary study of tumor hypoxia and tumor biology

    International Nuclear Information System (INIS)

    Varia, Mahesh A.; Kennedy, Andrew S.; Calkins-Adams, Dennise P.; Rinker, Lillian; Novotny, Debra; Fowler, Wesley C.; Raleigh, James A.

    1997-01-01

    Purpose/Objectives: Tumor hypoxia appears to be associated with treatment resistance and with gene expression that may lead to hypoxia-mediated selection of tumor cells as a source for cell growth and metastases. The objective of this study was to develop complementary techniques of hypoxia detection with molecular markers of cell proliferation and metastases in order to investigate the role of tumor hypoxia in tumor biology. Materials and Methods: Pimonidazole is a 2-nitroimidazole which is reductively-activated and becomes covalently bound to thiol-containing proteins only in hypoxic cells. These adducts can be detected using immunohistochemistry, enzyme linked immunosorbent assay or flow cytometry as a measure of hypoxia in tumors. Quantitative immunohistochemical analysis has been completed for five patients with squamous cell carcinoma of the cervix who were given pimonidazole hydrochloride (0.5 g/m 2 intravenously) followed by cervical biopsies 24 hours later. Informed consent was obtained according to a protocol approved by the Institutional Review Board. A minimum of 3 random biopsies were obtained from the tumors and at least four sections examined from each biopsy site. Formalin fixed, paraffin embedded tissue sections were immunostained for pimonidazole binding using a mouse monoclonal antibody. Commercially available monoclonal antibodies were used to detect cell proliferation markers MIB-1 (Ki-67) and to detect vascular endothelial growth factor (VEGF) in tumor cells in contiguous sections. The extent of immunostaining was expressed as the percent of immunostained to total tumor cells as determined by Chalkley point counting. Results: No clinical toxicities were associated with pimonidazole infusion. Immunostaining with pimonidazole antibody was observed in all patients indicating the presence of tumor hypoxia. Qualitatively there is little or no overlap between the areas of hypoxia and proliferation. Quantitative data tabulated below show the

  19. Canonical Wnt signaling induces a primitive endoderm metastable state in mouse embryonic stem cells.

    Science.gov (United States)

    Price, Feodor D; Yin, Hang; Jones, Andrew; van Ijcken, Wilfred; Grosveld, Frank; Rudnicki, Michael A

    2013-04-01

    Activation of the canonical Wnt signaling pathway synergizes with leukemia inhibitory factor (LIF) to maintain pluripotency of mouse embryonic stem cells (mESCs). However, in the absence of LIF, Wnt signaling is unable to maintain ESCs in the undifferentiated state. To investigate the role of canonical Wnt signaling in pluripotency and lineage specification, we expressed Wnt3a in mESCs and characterized them in growth and differentiation. We found that activated canonical Wnt signaling induced the formation of a reversible metastable primitive endoderm state in mESC. Upon subsequent differentiation, Wnt3a-stimulated mESCs gave rise to large quantities of visceral endoderm. Furthermore, we determined that the ability of canonical Wnt signaling to induce a metastable primitive endoderm state was mediated by Tbx3. Our data demonstrates a specific role for canonical Wnt signaling in promoting pluripotency while at the same time priming cells for subsequent differentiation into the primitive endoderm lineage. Copyright © 2013 AlphaMed Press.

  20. The Wnt antagonist, Dickkopf-1, as a target for the treatment of neurodegenerative disorders

    NARCIS (Netherlands)

    Caraci, Filippo; Busceti, Carla; Biagioni, Francesca; Aronica, Eleonora; Mastroiacovo, Federica; Cappuccio, Irene; Battaglia, Giuseppe; Bruno, Valeria; Caricasole, Andrea; Copani, Agata; Nicoletti, Ferdinando

    2008-01-01

    The canonical Wnt pathway contributes to the regulation of neuronal survival and homeostasis in the CNS. Recent evidence suggests that an increased expression of Dickkopf-1 (Dkk-1), a secreted protein that negatively modulates the canonical Wnt pathway, is causally related to processes of

  1. Amino acid limitation induces down-regulation of WNT5a at transcriptional level

    International Nuclear Information System (INIS)

    Wang Zuguang; Chen Hong

    2009-01-01

    An aberrant WNT signaling contributes to the development and progression of multiple cancers. WNT5a is one of the WNT signaling molecules. This study was designed to test the hypothesis that amino acid deprivation induces changes in the WNT signaling pathway in colon cancer cells. Results showed that targets of the amino acid response pathway, ATF3 and p21, were induced in the human colon cancer cell line SW480 during amino acid limitation. There was a significant decrease in the WNT5a mRNA level following amino acid deprivation. The down-regulation of WNT5a mRNA by amino acid deprivation is not due to mRNA destabilization. There is a reduction of nuclear β-catenin protein level by amino acid limitation. Under amino acid limitation, phosphorylation of ERK1/2 was increased and the blockage of ERK1/2 by the inhibitor U0126 partially restored WNT5a mRNA level. In conclusion, amino acid limitation in colon cancer cells induces phosphorylation of ERK1/2, which then down-regulates WNT5a expression.

  2. Cell intrinsic modulation of Wnt signaling controls neuroblast migration in C. elegans

    NARCIS (Netherlands)

    Mentink, Remco A; Middelkoop, Teije C; Rella, Lorenzo; Ji, Ni; Tang, Chung Yin; Betist, Marco C; van Oudenaarden, Alexander; Korswagen, Hendrik C

    2014-01-01

    Members of the Wnt family of secreted signaling proteins are key regulators of cell migration and axon guidance. In the nematode C. elegans, the migration of the QR neuroblast descendants requires multiple Wnt ligands and receptors. We found that the migration of the QR descendants is divided into

  3. Indian Hedgehog is an antagonist of Wnt signaling in colonic epithelial cell differentiation

    NARCIS (Netherlands)

    van den Brink, Gijs R.; Bleuming, Sylvia A.; Hardwick, James C. H.; Schepman, Berber L.; Offerhaus, G. Johan; Keller, Josbert J.; Nielsen, Corinne; Gaffield, William; van Deventer, Sander J. H.; Roberts, Drucilla J.; Peppelenbosch, Maikel P.

    2004-01-01

    Wnt signaling defines the colonic epithelial progenitor cell phenotype(1), and mutations in the gene adenomatous polyposis coli (APC) that activate the Wnt pathway cause the familial adenomatous polyposis coli (FAP) syndrome and most sporadic colon cancers(2). The mechanisms that regulate the

  4. Boehmenan, a lignan from Hibiscus ficulneus, showed Wnt signal inhibitory activity.

    Science.gov (United States)

    Shono, Takumi; Ishikawa, Naoki; Toume, Kazufumi; Arai, Midori A; Ahmed, Firoj; Sadhu, Samir K; Ishibashi, Masami

    2015-07-15

    The Wnt signal pathway modulates numerous biological processes, and its aberrant activation is related to various diseases. Therefore, inhibition of the Wnt signal may provide an effective (or efficient) strategy for these diseases. Cell-based luciferase assay targeting the Wnt signal (TOP assay) revealed that Hibiscus ficulneus extract inhibited the Wnt signal. The activity-guided isolation of the MeOH extract of H. ficulneus stems yielded four known (1-4) lignans along with myriceric acid (5). Compounds 1-4 potently inhibited the Wnt signal with TOPflash IC50 values of 1.0, 4.5, 6.3, and 1.9 μM, respectively. Compound 1 exhibited cytotoxicity against both Wnt-dependent (HCT116) and Wnt-independent (RKO) cells. Western blot analysis showed that 1 decreased the expression of full, cytosolic and nuclear β-catenin along with c-myc in STF/293 cells. Our results suggested that 1 may have inhibited the Wnt signal by decreasing β-catenin levels. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Sequence analysis and molecular characterization of Wnt4 gene in metacestodes of Taenia solium.

    Science.gov (United States)

    Hou, Junling; Luo, Xuenong; Wang, Shuai; Yin, Cai; Zhang, Shaohua; Zhu, Xueliang; Dou, Yongxi; Cai, Xuepeng

    2014-04-01

    Wnt proteins are a family of secreted glycoproteins that are evolutionarily conserved and considered to be involved in extensive developmental processes in metazoan organisms. The characterization of wnt genes may improve understanding the parasite's development. In the present study, a wnt4 gene encoding 491amino acids was amplified from cDNA of metacestodes of Taenia solium using reverse transcription PCR (RT-PCR). Bioinformatics tools were used for sequence analysis. The conserved domain of the wnt gene family was predicted. The expression profile of Wnt4 was investigated using real-time PCR. Wnt4 expression was found to be dramatically increased in scolex evaginated cysticerci when compared to invaginated cysticerci. In situ hybridization showed that wnt4 gene was distributed in the posterior end of the worm along the primary body axis in evaginated cysticerci. These findings indicated that wnt4 may take part in the process of cysticerci evagination and play a role in scolex/bladder development of cysticerci of T. solium.

  6. Soy Components Genistein and Lunasin Regulate E-Cadherin and Wnt Signaling in Mammary Epithelial Cells

    Science.gov (United States)

    Enhanced Wnt/beta-catenin signaling and loss of E-cadherin expression are considered hallmarks of tumorigenesis. We previously showed by microarray gene profiling that dietary intake of soy-based AIN-93G diets altered components of Wnt/beta-catenin signaling in rat mammary epithelial cells. To furth...

  7. Porcine Circovirus-Like Virus P1 Inhibits Wnt Signaling Pathway in Vivo and in Vitro.

    Science.gov (United States)

    Zhu, Xuejiao; Wen, Libin; Sheng, Shaoyang; Wang, Wei; Xiao, Qi; Qu, Meng; Hu, Yiyi; Liu, Chuanmin; He, Kongwang

    2018-01-01

    Porcine circovirus-like virus P1 is an important pathogen of the current pig industry, the infection mechanism is not entirely clear. Wnt signaling pathway plays an important role in the growth of young animals and infection of some viruses. This study was designed to demonstrate the effects of P1 infection on the Wnt signaling pathway. In vivo experiments, we demonstrated the down-regulatory effects of P1 infection in piglets and mice on the downstream components expression levels of Wnt signaling pathway, and the effects of Wnt signaling pathway activation on the pathogenesis of P1. In vitro studies, we found P1 infection down-regulated protein level of β-catenin and mRNA level of mmp2, prevented the β-catenin from entering into nucleus, abolished the TCF/LEF promoter activity, proved that P1 could inhibit the activation of Wnt signaling pathway in vitro . Finally, we found that VP1 of P1 virus also had the inhibitory effects on Wnt signaling pathway in vitro , elucidated the mechanism of P1's inhibitory effects on the Wnt signaling pathway and offered the possibility that the suppression of Wnt signaling pathway was involved in the post-weaning multisystemic wasting syndrome (PMWS), laying a foundation for elucidating the pathogenesis of P1.

  8. Binding of canonical Wnt ligands to their receptor complexes occurs in ordered plasma membrane environments.

    Science.gov (United States)

    Sezgin, Erdinc; Azbazdar, Yagmur; Ng, Xue W; Teh, Cathleen; Simons, Kai; Weidinger, Gilbert; Wohland, Thorsten; Eggeling, Christian; Ozhan, Gunes

    2017-08-01

    While the cytosolic events of Wnt/β-catenin signaling (canonical Wnt signaling) pathway have been widely studied, only little is known about the molecular mechanisms involved in Wnt binding to its receptors at the plasma membrane. Here, we reveal the influence of the immediate plasma membrane environment on the canonical Wnt-receptor interaction. While the receptors are distributed both in ordered and disordered environments, Wnt binding to its receptors selectively occurs in more ordered membrane environments which appear to cointernalize with the Wnt-receptor complex. Moreover, Wnt/β-catenin signaling is significantly reduced when the membrane order is disturbed by specific inhibitors of certain lipids that prefer to localize at the ordered environments. Similarly, a reduction in Wnt signaling activity is observed in Niemann-Pick Type C disease cells where trafficking of ordered membrane lipid components to the plasma membrane is genetically impaired. We thus conclude that ordered plasma membrane environments are essential for binding of canonical Wnts to their receptor complexes and downstream signaling activity. © 2017 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

  9. Noncanonical WNT-5A signaling impairs endogenous lung repair in COPD

    Science.gov (United States)

    Baarsma, Hoeke A.; John-Schuster, Gerrit; Heinzelmann, Katharina; Dagouassat, Maylis; Boczkowski, Jorge; Brusselle, Guy G.; Smits, Ron; Yildirim, Ali Ö.

    2017-01-01

    Chronic obstructive pulmonary disease (COPD) is a leading cause of death worldwide. One main pathological feature of COPD is the loss of functional alveolar tissue without adequate repair (emphysema), yet the underlying mechanisms are poorly defined. Reduced WNT–β-catenin signaling is linked to impaired lung repair in COPD; however, the factors responsible for attenuating this pathway remain to be elucidated. Here, we identify a canonical to noncanonical WNT signaling shift contributing to COPD pathogenesis. We demonstrate enhanced expression of noncanonical WNT-5A in two experimental models of COPD and increased posttranslationally modified WNT-5A in human COPD tissue specimens. WNT-5A was increased in primary lung fibroblasts from COPD patients and induced by COPD-related stimuli, such as TGF-β, cigarette smoke (CS), and cellular senescence. Functionally, mature WNT-5A attenuated canonical WNT-driven alveolar epithelial cell wound healing and transdifferentiation in vitro. Lung-specific WNT-5A overexpression exacerbated airspace enlargement in elastase-induced emphysema in vivo. Accordingly, inhibition of WNT-5A in vivo attenuated lung tissue destruction, improved lung function, and restored expression of β-catenin–driven target genes and alveolar epithelial cell markers in the elastase, as well as in CS-induced models of COPD. We thus identify a novel essential mechanism involved in impaired mesenchymal–epithelial cross talk in COPD pathogenesis, which is amenable to therapy. PMID:27979969

  10. NRAGE induces β-catenin/Arm O-GlcNAcylation and negatively regulates Wnt signaling

    International Nuclear Information System (INIS)

    Chen, Yuxin; Jin, Lei; Xue, Bin; Jin, Dong; Sun, Fenyong; Wen, Chuanjun

    2017-01-01

    The Wnt pathway is crucial for animal development, as well as tumor formation. Understanding the regulation of Wnt signaling will help to elucidate the mechanism of the cell cycle, cell differentiation and tumorigenesis. It is generally accepted that in response to Wnt signals, β-catenin accumulates in the cytoplasm and is imported into the nucleus where it recruits LEF/TCF transcription factors to activate the expression of target genes. In this study, we report that human NRAGE, a neurotrophin receptor p75 (p75NTR) binding protein, markedly suppresses the expression of genes activated by the Wnt pathway. Consistent with this finding, loss of function of NRAGE by RNA interference (RNAi) activates the Wnt pathway. Moreover, NRAGE suppresses the induction of axis duplication by microinjected β-catenin in Xenopus embryos. To our surprise, NRAGE induces nuclear localization of β-catenin and increases its DNA binding ability. Further studies reveal that NRAGE leads to the modification of β-catenin/Arm with O-linked beta-N-acetylglucosamine (O-GlcNAc), and failure of the association between β-catenin/Arm and pygopus(pygo) protein, which is required for transcriptional activation of Wnt target genes. Therefore, our findings suggest a novel mechanism for regulating Wnt signaling. - Highlights: • NRAGE suppresses the expressions of Wnt pathway downstream genes. • NRAGE induces nuclear localization of β-catenin and increases its DNA binding ability. • NRAGE activity leads to the O-GlcNAcylation of β-catenin.

  11. Efficient Purification and Optimization of Wnt3a, a Novel Therapeutic for Tissue Regeneration

    Science.gov (United States)

    Madhav, D.; Helms, J.; Dhamdhere, G.

    2012-12-01

    Wnt is a secreted protein that is present naturally in the body. When an organism is injured the amount of Wnt in the affected area increases. This protein acts as an activator of adult stem cells and signals them to begin differentiating and proliferating. This stem cell response augments the ongoing efforts of injured cells to heal faster by becoming the cells that were damaged by the injury. Adult stem cells play a great role in the healing of wounds, but as organisms age the amount of stem cells in their body decreases. This decrease, in effect, slows the healing of injuries because no stem cells are present to help the regenerative efforts of the body. The Wnt protein induces these stem cells not only to differentiate and proliferate, but also to self-replicate. The ability of Wnt to induce adult stem cells to self -replicate gives us an option to use the protein as a potential tissue regenerative drug. Post-translational Wnt has a lipid modification that makes the protein insoluble in water. To overcome this we fuse the protein with a liposome. A liposome is a lipid sphere with an aqueous center and a phospholipid membrane. The Wnt protein does not lose its function when joined with a liposome. Using this knowledge we can develop a viable means to inject the Wnt protein directly into organisms. The big problem now is to make enough purified Wnt to manufacture on a large scale.

  12. The role of Ryk and Ror receptor tyrosine kinases in Wnt signal transduction

    NARCIS (Netherlands)

    Green, J.; Nusse, R.; van Amerongen, R.

    2014-01-01

    Receptor tyrosine kinases of the Ryk and Ror families were initially classified as orphan receptors because their ligands were unknown. They are now known to contain functional extracellular Wnt-binding domains and are implicated in Wnt-signal transduction in multiple species. Although their

  13. Effects of genetic variants of the bovine WNT8A gene on nine ...

    Indian Academy of Sciences (India)

    2016-11-15

    Nov 15, 2016 ... College of Veterinary Medicine, Northwest A & F University, Yangling, Shaanxi ... using DNA pool sequencing and PCR–RFLP method. ... outputs of the complex Wnt8A locus and regulated the mesodermal patterning and .... structure analysis of the Wnt8A gene in the Qinchuan cattle population is shown in.

  14. Wnt signaling balances specification of the cardiac and pharyngeal muscle fields

    Science.gov (United States)

    Mandal, Amrita; Holowiecki, Andrew; Song, Yuntao Charlie; Waxman, Joshua S.

    2017-01-01

    Canonical Wnt/β-catenin (Wnt) signaling plays multiple conserved roles during fate specification of cardiac progenitors in developing vertebrate embryos. Although lineage analysis in ascidians and mice has indicated there is a close relationship between the cardiac second heart field (SHF) and pharyngeal muscle (PM) progenitors, the signals underlying directional fate decisions of the cells within the cardio-pharyngeal muscle field in vertebrates are not yet understood. Here, we examined the temporal requirements of Wnt signaling in cardiac and PM development. In contrast to a previous report in chicken embryos that suggested Wnt inhibits PM development during somitogenesis, we find that in zebrafish embryos Wnt signaling is sufficient to repress PM development during anterior-posterior patterning. Importantly, the temporal sensitivity of dorso-anterior PMs to increased Wnt signaling largely overlaps with when Wnt signaling promotes specification of the adjacent cardiac progenitors. Furthermore, we find that excess early Wnt signaling can cell autonomously promote expansion of the first heart field (FHF) progenitors at the expense of PM and SHF within the anterior lateral plate mesoderm (ALPM). Our study provides insight into an antagonistic developmental mechanism that balances the sizes of the adjacent cardiac and PM progenitor fields in early vertebrate embryos. PMID:28087459

  15. Porcine Circovirus-Like Virus P1 Inhibits Wnt Signaling Pathway in Vivo and in Vitro

    Directory of Open Access Journals (Sweden)

    Xuejiao Zhu

    2018-03-01

    Full Text Available Porcine circovirus-like virus P1 is an important pathogen of the current pig industry, the infection mechanism is not entirely clear. Wnt signaling pathway plays an important role in the growth of young animals and infection of some viruses. This study was designed to demonstrate the effects of P1 infection on the Wnt signaling pathway. In vivo experiments, we demonstrated the down-regulatory effects of P1 infection in piglets and mice on the downstream components expression levels of Wnt signaling pathway, and the effects of Wnt signaling pathway activation on the pathogenesis of P1. In vitro studies, we found P1 infection down-regulated protein level of β-catenin and mRNA level of mmp2, prevented the β-catenin from entering into nucleus, abolished the TCF/LEF promoter activity, proved that P1 could inhibit the activation of Wnt signaling pathway in vitro. Finally, we found that VP1 of P1 virus also had the inhibitory effects on Wnt signaling pathway in vitro, elucidated the mechanism of P1’s inhibitory effects on the Wnt signaling pathway and offered the possibility that the suppression of Wnt signaling pathway was involved in the post-weaning multisystemic wasting syndrome (PMWS, laying a foundation for elucidating the pathogenesis of P1.

  16. Effects of Wnt signaling on brown adipocyte differentiation and metabolism mediated by PGC-1alpha

    DEFF Research Database (Denmark)

    Kang, Sona; Bajnok, Laszlo; Longo, Kenneth A

    2005-01-01

    Activation of canonical Wnt signaling inhibits brown adipogenesis of cultured cells by impeding induction of PPARgamma and C/EBPalpha. Although enforced expression of these adipogenic transcription factors restores lipid accumulation and expression of FABP4 in Wnt-expressing cells, additional...

  17. Wnt ligand presentation and reception: from the stem cell niche to tissue engineering.

    Science.gov (United States)

    Mills, Kate M; Szczerkowski, James L A; Habib, Shukry J

    2017-08-01

    Stem cells reside in niches where spatially restricted signals maintain a delicate balance between stem cell self-renewal and differentiation. Wnt family proteins are particularly suited for this role as they are modified by lipids, which constrain and spatially regulate their signalling range. In recent years, Wnt/β-catenin signalling has been shown to be essential for the self-renewal of a variety of mammalian stem cells. In this review, we discuss Wnt-responsive stem cells in their niche, and mechanisms by which Wnt ligands are presented to responsive cells. We also highlight recent progress in molecular visualization that has allowed for the monitoring of Wnt signalling within the stem cell compartment and new approaches to recapitulate this niche signalling in vitro Indeed, new technologies that present Wnt in a localized manner and mimic the three-dimensional microenvironment of stem cells will advance our understanding of Wnt signalling in the stem cell niche. These advances will expand current horizons to exploit Wnt ligands in the rapidly evolving fields of tissue engineering and regenerative medicine. © 2017 The Authors.

  18. Interrelationship of canonical and non-canonical Wnt signalling pathways in chronic metabolic diseases.

    Science.gov (United States)

    Ackers, Ian; Malgor, Ramiro

    2018-01-01

    Chronic diseases account for approximately 45% of all deaths in developed countries and are particularly prevalent in countries with the most sophisticated and robust public health systems. Chronic metabolic diseases, specifically lifestyle-related diseases pertaining to diet and exercise, continue to be difficult to treat clinically. The most prevalent of these chronic metabolic diseases include obesity, diabetes, non-alcoholic fatty liver disease, chronic kidney disease and cardiovascular disease and will be the focus of this review. Wnt proteins are highly conserved glycoproteins best known for their role in development and homeostasis of tissues. Given the importance of Wnt signalling in homeostasis, aberrant Wnt signalling likely regulates metabolic processes and may contribute to the development of chronic metabolic diseases. Expression of Wnt proteins and dysfunctional Wnt signalling has been reported in multiple chronic diseases. It is interesting to speculate about an interrelationship between the Wnt signalling pathways as a potential pathological mechanism in chronic metabolic diseases. The aim of this review is to summarize reported findings on the contrasting roles of Wnt signalling in lifestyle-related chronic metabolic diseases; specifically, the contribution of Wnt signalling to lipid accumulation, fibrosis and chronic low-grade inflammation.

  19. A review of the evidence for the canonical Wnt pathway in autism spectrum disorders

    Directory of Open Access Journals (Sweden)

    Kalkman Hans

    2012-10-01

    Full Text Available Abstract Microdeletion and microduplication copy number variations are found in patients with autism spectrum disorder and in a number of cases they include genes that are involved in the canonical Wnt signaling pathway (for example, FZD9, BCL9 or CDH8. Association studies investigating WNT2, DISC1, MET, DOCK4 or AHI1 also provide evidence that the canonical Wnt pathway might be affected in autism. Prenatal medication with sodium-valproate or antidepressant drugs increases autism risk. In animal studies, it has been found that these medications promote Wnt signaling, including among others an increase in Wnt2 gene expression. Notably, the available genetic information indicates that not only canonical Wnt pathway activation, but also inhibition seems to increase autism risk. The canonical Wnt pathway plays a role in dendrite growth and suboptimal activity negatively affects the dendritic arbor. In principle, this provides a logical explanation as to why both hypo- and hyperactivity may generate a similar set of behavioral and cognitive symptoms. However, without a validated biomarker to stratify for deviant canonical Wnt pathway activity, it is probably too dangerous to treat patients with compounds that modify pathway activity.

  20. Making sense of Wnt signaling – linking hair cell regeneration to development

    Directory of Open Access Journals (Sweden)

    Lina eJansson

    2015-03-01

    Full Text Available Wnt signaling is a highly conserved pathway crucial for development and homeostasis of multicellular organisms. Secreted Wnt ligands bind Frizzled receptors to regulate diverse processes such as axis patterning, cell division, and cell fate specification. They also serve to govern self-renewal of somatic stem cells in several adult tissues. The complexity of the pathway can be attributed to the myriad of Wnt and Frizzled combinations as well as its diverse context-dependent functions. In the developing mouse inner ear, Wnt signaling plays diverse roles, including specification of the otic placode and patterning of the otic vesicle. At later stages, its activity governs sensory hair cell specification, cell cycle regulation, and hair cell orientation. In regenerating sensory organs from non-mammalian species, Wnt signaling can also regulate the extent of proliferative hair cell regeneration. This review describes the current knowledge of the roles of Wnt signaling and Wnt-responsive cells in hair cell development and regeneration. We also discuss possible future directions and the potential application and limitation of Wnt signaling in augmenting hair cell regeneration.

  1. Wnt-β-Catenin Signaling Promotes the Maturation of Mast Cells

    Directory of Open Access Journals (Sweden)

    Tomoko Yamaguchi

    2016-01-01

    Full Text Available Mast cells play an important role in the pathogenesis of allergic diseases. Immature mast cells migrate into peripheral tissues from the bone marrow and undergo complete maturation. Interestingly, mast cells have characteristics similar to hematopoietic stem cells (HSCs, such as self-renewal and c-kit expression. In HSCs, Wnt signaling is involved in their maintenance and differentiation. On the other hand, the relation between Wnt signaling and mast cell differentiation is poorly understood. To study whether Wnt signals play a role in the maturation of mast cells, we studied the effect of Wnt proteins on mast cell maturation of bone marrow-derived mast cells (BMMCs. The expression levels of CD81 protein and histidine decarboxylase mRNA and activity of mast cell-specific protease were all elevated in BMMCs treated with Wnt5a. In addition, Wnt5a induced the expression of Axin2 and TCF mRNA in BMMCs. These results showed that Wnt5a could promote the maturation of mast cells via the canonical Wnt signaling pathway and provide important insights into the molecular mechanisms underlying the differentiation of mast cells.

  2. Regulation of mRNA translation influences hypoxia tolerance

    International Nuclear Information System (INIS)

    Koritzinsky, M.; Wouters, B.G.; Koumenis, C.

    2003-01-01

    Hypoxia is a heterogenous but common characteristic of human tumours and poor oxygenation is associated with poor prognosis. We believe that the presence of viable hypoxic tumor cells reflects in part an adaptation and tolerance of these cells to oxygen deficiency. Since oxidative phosphorylation is compromized during hypoxia, adaptation may involve both the upregulation of glycolysis as well as downregulation of energy consumption. mRNA translation is one of the most energy costly cellular processes, and we and others have shown that global mRNA translation is rapidly inhibited during hypoxia. However, some mRNAs, including those coding for HIF-1 α and VEGF, remain efficiently translated during hypoxia. Clearly, the mechanisms responsible for the overall inhibition of translation during hypoxia does not compromize the translation of certain hypoxia-induced mRNA species. We therefore hypothesize that the inhibition of mRNA translation serves to promote hypoxia tolerance in two ways: i) through conservation of energy and ii) through differential gene expression involved in hypoxia adaptation. We have recently identified two pathways that are responsible for the global inhibition of translation during hypoxia. The phosphorylation of the eukaryotic initiation factor eIF2 α by the ER resident kinase PERK results in down-regulation of protein synthesis shortly after the onset of hypoxia. In addition, the initiation complex eIF4F is disrupted during long lasting hypoxic conditions. The identification of the molecular pathways responsible for the inhibition of overall translation during hypoxia has rendered it possible to investigate their importance for hypoxia tolerance. We have found that mouse embryo fibroblasts that are knockout for PERK and therefore not able to inhibit protein synthesis efficiently during oxygen deficiency are significantly less tolerant to hypoxia than their wildtype counterparts. We are currently also investigating the functional significance

  3. Poly(ferrocenylsilane)-block-Polylactide Block Copolymers

    NARCIS (Netherlands)

    Roerdink, M.; van Zanten, Thomas S.; Hempenius, Mark A.; Zhong, Zhiyuan; Feijen, Jan; Vancso, Gyula J.

    2007-01-01

    A PFS/PLA block copolymer was studied to probe the effect of strong surface interactions on pattern formation in PFS block copolymer thin films. Successful synthesis of PFS-b-PLA was demonstrated. Thin films of these polymers show phase separation to form PFS microdomains in a PLA matrix, and

  4. Wnt modulates MCL1 to control cell survival in triple negative breast cancer

    International Nuclear Information System (INIS)

    Yang, Lixin; Zhang, Hang; Zheng, Shu; Liu, Zheng; Ann, David; Yen, Yun; Perez, Aldwin Apollo; Fujie, Sayuri; Warden, Charles; Li, Jie; Wang, Yafan; Yung, Bryan; Chen, Yun-Ru; Liu, Xiyong

    2014-01-01

    Triple negative breast cancer (TNBC) has higher rates of recurrence and distant metastasis, and poorer outcome as compared to non-TNBC. Aberrant activation of WNT signaling has been detected in TNBC, which might be important for triggering oncogenic conversion of breast epithelial cell. Therefore, we directed our focus on identifying the WNT ligand and its underlying mechanism in TNBC cells. We performed large-scale analysis of public microarray data to screen the WNT ligands and the clinical significance of the responsible ligand in TNBC. WNT5B was identified and its overexpression in TNBC was confirmed by immunohistochemistry staining, Western blot and ELISA. ShRNA was used to knockdown WNT5B expression (shWNT5B). Cellular functional alteration with shWNT5B treatment was determined by using wound healing assay, mammosphere assay; while cell cycle and apoptosis were examined by flowcytometry. Mitochondrial morphology was photographed by electron microscope. Biological change of mitochondria was detected by RT-PCR and oxygen consumption assay. Activation of WNT pathway and its downstream targets were evaluated by liciferase assay, immunohistochemistry staining and immunoblot analysis. Statistical methods used in the experiments besides microarray analysis was two-tailed t-test. WNT5B was elevated both in the tumor and the patients’ serum. Suppression of WNT5B remarkably impaired cell growth, migration and mammosphere formation. Additionally, G0/G1 cell cycle arrest and caspase-independent apoptosis was observed. Study of the possible mechanism indicated that these effects occurred through suppression of mitochondrial biogenesis, as evidenced by reduced mitochondrial DNA (MtDNA) and compromised oxidative phosphorylation (OXPHOS). In Vivo and in vitro data uncovered that WNT5B modulated mitochondrial physiology was mediated by MCL1, which was regulated by WNT/β-catenin responsive gene, Myc. Clinic data analysis revealed that both WNT5B and MCL1 are associated with

  5. Wnt5a signaling is a substantial constituent in bone morphogenetic protein-2-mediated osteoblastogenesis

    International Nuclear Information System (INIS)

    Nemoto, Eiji; Ebe, Yukari; Kanaya, Sousuke; Tsuchiya, Masahiro; Nakamura, Takashi; Tamura, Masato; Shimauchi, Hidetoshi

    2012-01-01

    Highlights: ► Wnt5a is identified in osteoblasts in tibial growth plate and bone marrow. ► Osteoblastic differentiation is associated with increased expression of Wnt5a/Ror2. ► Wnt5a/Ror2 signaling is important for BMP-2-mediated osteoblastic differentiation. ► Wnt5a/Ror2 operates independently of BMP-Smad pathway. -- Abstract: Wnts are secreted glycoproteins that mediate developmental and post-developmental physiology by regulating cellular processes including proliferation, differentiation, and apoptosis through β-catenin-dependent canonical and β-catenin-independent noncanonical pathway. It has been reported that Wnt5a activates noncanonical Wnt signaling through receptor tyrosine kinase-like orphan receptor 2 (Ror2). Although it appears that Wnt5a/Ror2 signaling supports normal bone physiology, the biological significance of noncanonical Wnts in osteogenesis is essentially unknown. In this study, we identified expression of Wnt5a in osteoblasts in the ossification zone of the tibial growth plate as well as bone marrow of the rat tibia as assessed by immunohistochemistry. In addition, we show that osteoblastic differentiation mediated by BMP-2 is associated with increased expression of Wnt5a and Ror2 using cultured pre-osteoblasts, MC3T3-E1 cells. Silencing gene expression of Wnt5a and Ror2 in MC3T3-E1 cells results in suppression of BMP-2-mediated osteoblastic differentiation, suggesting that Wnt5a and Ror2 signaling are of substantial importance for BMP-2-mediated osteoblastic differentiation. BMP-2 stimulation induced phosphorylation of Smad1/5/8 in a similar fashion in both siWnt5a-treated cells and control cells, suggesting that Wnt5a was dispensable for the phosphorylation of Smads by BMP-2. Taken together, our results suggest that Wnt5a/Ror2 signaling appears to be involved in BMP-2-mediated osteoblast differentiation in a Smad independent pathway.

  6. Wnt pathway reprogramming during human embryonal carcinoma differentiation and potential for therapeutic targeting

    International Nuclear Information System (INIS)

    Snow, Grace E; Kasper, Allison C; Busch, Alexander M; Schwarz, Elisabeth; Ewings, Katherine E; Bee, Thomas; Spinella, Michael J; Dmitrovsky, Ethan; Freemantle, Sarah J

    2009-01-01

    Testicular germ cell tumors (TGCTs) are classified as seminonas or non-seminomas of which a major subset is embryonal carcinoma (EC) that can differentiate into diverse tissues. The pluripotent nature of human ECs resembles that of embryonic stem (ES) cells. Many Wnt signalling species are regulated during differentiation of TGCT-derived EC cells. This study comprehensively investigated expression profiles of Wnt signalling components regulated during induced differentiation of EC cells and explored the role of key components in maintaining pluripotency. Human embryonal carcinoma cells were stably infected with a lentiviral construct carrying a canonical Wnt responsive reporter to assess Wnt signalling activity following induced differentiation. Cells were differentiated with all-trans retinoic acid (RA) or by targeted repression of pluripotency factor, POU5F1. A Wnt pathway real-time-PCR array was used to evaluate changes in gene expression as cells differentiated. Highlighted Wnt pathway genes were then specifically repressed using siRNA or stable shRNA and transfected EC cells were assessed for proliferation, differentiation status and levels of core pluripotency genes. Canonical Wnt signalling activity was low basally in undifferentiated EC cells, but substantially increased with induced differentiation. Wnt pathway gene expression levels were compared during induced differentiation and many components were altered including ligands (WNT2B), receptors (FZD5, FZD6, FZD10), secreted inhibitors (SFRP4, SFRP1), and other effectors of Wnt signalling (FRAT2, DAAM1, PITX2, Porcupine). Independent repression of FZD5, FZD7 and WNT5A using transient as well as stable methods of RNA interference (RNAi) inhibited cell growth of pluripotent NT2/D1 human EC cells, but did not appreciably induce differentiation or repress key pluripotency genes. Silencing of FZD7 gave the greatest growth suppression in all human EC cell lines tested including NT2/D1, NT2/D1-R1, Tera-1 and 833

  7. Anteroposterior axis patterning by early canonical Wnt signaling during hemichordate development

    Science.gov (United States)

    Darras, Sébastien; Fritzenwanker, Jens H.; Uhlinger, Kevin R.; Farrelly, Ellyn; Pani, Ariel M.; Hurley, Imogen A.; Norris, Rachael P.; Osovitz, Michelle; Terasaki, Mark; Wu, Mike; Aronowicz, Jochanan; Kirschner, Marc; Gerhart, John C.

    2018-01-01

    The Wnt family of secreted proteins has been proposed to play a conserved role in early specification of the bilaterian anteroposterior (A/P) axis. This hypothesis is based predominantly on data from vertebrate embryogenesis as well as planarian regeneration and homeostasis, indicating that canonical Wnt (cWnt) signaling endows cells with positional information along the A/P axis. Outside of these phyla, there is strong support for a conserved role of cWnt signaling in the repression of anterior fates, but little comparative support for a conserved role in promotion of posterior fates. We further test the hypothesis by investigating the role of cWnt signaling during early patterning along the A/P axis of the hemichordate Saccoglossus kowalevskii. We have cloned and investigated the expression of the complete Wnt ligand and Frizzled receptor complement of S. kowalevskii during early development along with many secreted Wnt modifiers. Eleven of the 13 Wnt ligands are ectodermally expressed in overlapping domains, predominantly in the posterior, and Wnt antagonists are localized predominantly to the anterior ectoderm in a pattern reminiscent of their distribution in vertebrate embryos. Overexpression and knockdown experiments, in combination with embryological manipulations, establish the importance of cWnt signaling for repression of anterior fates and activation of mid-axial ectodermal fates during the early development of S. kowalevskii. However, surprisingly, terminal posterior fates, defined by posterior Hox genes, are unresponsive to manipulation of cWnt levels during the early establishment of the A/P axis at late blastula and early gastrula. We establish experimental support for a conserved role of Wnt signaling in the early specification of the A/P axis during deuterostome body plan diversification, and further build support for an ancestral role of this pathway in early evolution of the bilaterian A/P axis. We find strong support for a role of cWnt in

  8. M2 macrophages activate WNT signaling pathway in epithelial cells: relevance in ulcerative colitis.

    Directory of Open Access Journals (Sweden)

    Jesús Cosín-Roger

    Full Text Available Macrophages, which exhibit great plasticity, are important components of the inflamed tissue and constitute an essential element of regenerative responses. Epithelial Wnt signalling is involved in mechanisms of proliferation and differentiation and expression of Wnt ligands by macrophages has been reported. We aim to determine whether the macrophage phenotype determines the expression of Wnt ligands, the influence of the macrophage phenotype in epithelial activation of Wnt signalling and the relevance of this pathway in ulcerative colitis. Human monocyte-derived macrophages and U937-derived macrophages were polarized towards M1 or M2 phenotypes and the expression of Wnt1 and Wnt3a was analyzed by qPCR. The effects of macrophages and the role of Wnt1 were analyzed on the expression of β-catenin, Tcf-4, c-Myc and markers of cell differentiation in a co-culture system with Caco-2 cells. Immunohistochemical staining of CD68, CD206, CD86, Wnt1, β-catenin and c-Myc were evaluated in the damaged and non-damaged mucosa of patients with UC. We also determined the mRNA expression of Lgr5 and c-Myc by qPCR and protein levels of β-catenin by western blot. Results show that M2, and no M1, activated the Wnt signaling pathway in co-culture epithelial cells through Wnt1 which impaired enterocyte differentiation. A significant increase in the number of CD206+ macrophages was observed in the damaged mucosa of chronic vs newly diagnosed patients. CD206 immunostaining co-localized with Wnt1 in the mucosa and these cells were associated with activation of canonical Wnt signalling pathway in epithelial cells and diminution of alkaline phosphatase activity. Our results show that M2 macrophages, and not M1, activate Wnt signalling pathways and decrease enterocyte differentiation in co-cultured epithelial cells. In the mucosa of UC patients, M2 macrophages increase with chronicity and are associated with activation of epithelial Wnt signalling and diminution in

  9. Surface topography regulates wnt signaling through control of primary cilia structure in mesenchymal stem cells

    Science.gov (United States)

    McMurray, R. J.; Wann, A. K. T.; Thompson, C. L.; Connelly, J. T.; Knight, M. M.

    2013-01-01

    The primary cilium regulates cellular signalling including influencing wnt sensitivity by sequestering β-catenin within the ciliary compartment. Topographic regulation of intracellular actin-myosin tension can control stem cell fate of which wnt is an important mediator. We hypothesized that topography influences mesenchymal stem cell (MSC) wnt signaling through the regulation of primary cilia structure and function. MSCs cultured on grooves expressed elongated primary cilia, through reduced actin organization. siRNA inhibition of anterograde intraflagellar transport (IFT88) reduced cilia length and increased active nuclear β-catenin. Conversely, increased primary cilia assembly in MSCs cultured on the grooves was associated with decreased levels of nuclear active β-catenin, axin-2 induction and proliferation, in response to wnt3a. This negative regulation, on grooved topography, was reversed by siRNA to IFT88. This indicates that subtle regulation of IFT and associated cilia structure, tunes the wnt response controlling stem cell differentiation. PMID:24346024

  10. The role of glypicans in Wnt inhibitory factor-1 activity and the structural basis of Wif1's effects on Wnt and Hedgehog signaling.

    Directory of Open Access Journals (Sweden)

    Andrei Avanesov

    Full Text Available Proper assignment of cellular fates relies on correct interpretation of Wnt and Hedgehog (Hh signals. Members of the Wnt Inhibitory Factor-1 (WIF1 family are secreted modulators of these extracellular signaling pathways. Vertebrate WIF1 binds Wnts and inhibits their signaling, but its Drosophila melanogaster ortholog Shifted (Shf binds Hh and extends the range of Hh activity in the developing D. melanogaster wing. Shf activity is thought to depend on reinforcing interactions between Hh and glypican HSPGs. Using zebrafish embryos and the heterologous system provided by D. melanogaster wing, we report on the contribution of glypican HSPGs to the Wnt-inhibiting activity of zebrafish Wif1 and on the protein domains responsible for the differences in Wif1 and Shf specificity. We show that Wif1 strengthens interactions between Wnt and glypicans, modulating the biphasic action of glypicans towards Wnt inhibition; conversely, glypicans and the glypican-binding "EGF-like" domains of Wif1 are required for Wif1's full Wnt-inhibiting activity. Chimeric constructs between Wif1 and Shf were used to investigate their specificities for Wnt and Hh signaling. Full Wnt inhibition required the "WIF" domain of Wif1, and the HSPG-binding EGF-like domains of either Wif1 or Shf. Full promotion of Hh signaling requires both the EGF-like domains of Shf and the WIF domains of either Wif1 or Shf. That the Wif1 WIF domain can increase the Hh promoting activity of Shf's EGF domains suggests it is capable of interacting with Hh. In fact, full-length Wif1 affected distribution and signaling of Hh in D. melanogaster, albeit weakly, suggesting a possible role for Wif1 as a modulator of vertebrate Hh signaling.

  11. Proteomic Alterations in Response to Hypoxia Inducible Factor 2α in Normoxic Neuroblastoma Cells.

    Science.gov (United States)

    Cimmino, Flora; Pezone, Lucia; Avitabile, Marianna; Persano, Luca; Vitale, Monica; Sassi, Mauro; Bresolin, Silvia; Serafin, Valentina; Zambrano, Nicola; Scaloni, Andrea; Basso, Giuseppe; Iolascon, Achille; Capasso, Mario

    2016-10-07

    Hypoxia inducible factor (HIF)-2α protein expression in solid tumors promotes stem-like phenotype in cancer stem cells and increases tumorigenic potential in nonstem cancer cells. Recently, we have shown that HIF-1/2α gene expression is correlated to neuroblastoma (NB) poor survival and to undifferentiated tumor state; HIF-2α protein was demonstrated to enhance aggressive features of the disease. In this study, we used proteomic experiments on NB cells to investigate HIF-2α downstream-regulated proteins or pathways with the aim of providing novel therapeutic targets or bad prognosis markers. We verified that pathways mostly altered by HIF-2α perturbation are involved in tumor progression. In particular, HIF-2α induces alteration of central metabolism and splicing control pathways. Simultaneously, WNT, RAS/MAPK, and PI3K/AKT activity or expression are affected and may impact the sensitivity and the intensity of HIF-2α-regulated pathways. Furthermore, genes coding the identified HIF-2α-related markers built a signature able to stratify NB patients with unfavorable outcome. Taken together, our findings underline the relevance of dissecting the downstream effects of a poor survival marker in developing targeted therapy and improving patient stratification. Future prospective studies are needed to translate the use of these data into the clinical practice.

  12. The Ewing sarcoma secretome and its response to activation of Wnt/beta-catenin signaling.

    Science.gov (United States)

    Hawkins, Allegra G; Basrur, Venkatesha; da Veiga Leprevost, Felipe; Pedersen, Elisabeth; Sperring, Colin; Nesvizhskii, Alexey I; Lawlor, Elizabeth R

    2018-01-31

    Tumor: tumor microenvironment (TME) interactions are critical for tumor progression and the composition and structure of the local extracellular matrix (ECM) are key determinants of tumor metastasis. We recently reported that activation of Wnt/beta-catenin signaling in Ewing sarcoma cells induces widespread transcriptional changes that are associated with acquisition of a metastatic tumor phenotype. Significantly, ECM protein-encoding genes were found to be enriched among Wnt/beta-catenin induced transcripts, leading us to hypothesize that activation of canonical Wnt signaling might induce changes in the Ewing sarcoma secretome. To address this hypothesis, conditioned media from Ewing sarcoma cell lines cultured in the presence or absence of Wnt3a was collected for proteomic analysis. Label-free mass spectrometry was used to identify and quantify differentially secreted proteins. We then used in silico databases to identify only proteins annotated as secreted. Comparison of the secretomes of two Ewing sarcoma cell lines revealed numerous shared proteins, as well as a degree of heterogeneity, in both basal and Wnt-stimulated conditions. Gene set enrichment analysis of secreted proteins revealed that Wnt stimulation reproducibly resulted in increased secretion of proteins involved in ECM organization, ECM receptor interactions, and collagen formation. In particular, Wnt-stimulated Ewing sarcoma cells upregulated secretion of structural collagens, as well as matricellular proteins, such as the metastasis-associated protein, tenascin C (TNC). Interrogation of published databases confirmed reproducible correlations between Wnt/beta-catenin activation and TNC and COL1A1 expression in patient tumors. In summary, this first study of the Ewing sarcoma secretome reveals that Wnt/beta-catenin activated tumor cells upregulate secretion of ECM proteins. Such Wnt/beta-catenin mediated changes are likely to impact on tumor: TME interactions that contribute to metastatic

  13. HPV16 E6 and E6AP differentially cooperate to stimulate or augment Wnt signaling

    International Nuclear Information System (INIS)

    Sominsky, Sophia; Kuslansky, Yael; Shapiro, Beny; Jackman, Anna; Haupt, Ygal; Rosin-Arbesfeld, Rina; Sherman, Levana

    2014-01-01

    The present study investigated the roles of E6 and E6AP in the Wnt pathway. We showed that E6 levels are markedly reduced in cells in which Wnt signaling is activated. Coexpression of wild-type or mutant E6AP (C820A) in Wnt-activated cells stabilized E6 and enhanced Wnt/β-catenin/TCF transcription. Expression of E6AP alone in nonstimulated cells elevated β-catenin level, promoted its nuclear accumulation, and activated β-catenin/TCF transcription. A knockdown of E6AP lowered β-catenin levels. Coexpression with E6 intensified the activities of E6AP. Further experiments proved that E6AP/E6 stabilize β-catenin by protecting it from proteasomal degradation. This function was dependent on the catalytic activity of E6AP, the kinase activity of GSK3β and the susceptibility of β-catenin to GSK3β phosphorylation. Thus, this study identified E6AP as a novel regulator of the Wnt signaling pathway, capable of cooperating with E6 in stimulating or augmenting Wnt/β-catenin signaling, thereby possibly contributing to HPV carcinogenesis. - Highlights: • The roles of E6 and E6AP in the Wnt pathway were investigated. • E6AP stabilizes E6 and enhances E6 activity in augmentation of Wnt signaling. • E6AP cooperates with E6 to stabilize β-catenin and stimulate Wnt/β-catenin signaling. • E6AP and E6 act through different mechanisms to augment or stimulate Wnt signaling

  14. HPV16 E6 and E6AP differentially cooperate to stimulate or augment Wnt signaling

    Energy Technology Data Exchange (ETDEWEB)

    Sominsky, Sophia, E-mail: sophia.tab@gmail.com [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Kuslansky, Yael, E-mail: ykuslansky@gmail.com [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Shapiro, Beny, E-mail: benyshap@gmail.com [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Jackman, Anna, E-mail: jackman@post.tau.ac.il [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Haupt, Ygal, E-mail: ygal.haupt@petermac.org [Research Division, The Peter MacCallum Cancer Centre, East Melbourne (Australia); Rosin-Arbesfeld, Rina, E-mail: arina@post.tau.ac.il [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel); Sherman, Levana, E-mail: lsherman@post.tau.ac.il [Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel)

    2014-11-15

    The present study investigated the roles of E6 and E6AP in the Wnt pathway. We showed that E6 levels are markedly reduced in cells in which Wnt signaling is activated. Coexpression of wild-type or mutant E6AP (C820A) in Wnt-activated cells stabilized E6 and enhanced Wnt/β-catenin/TCF transcription. Expression of E6AP alone in nonstimulated cells elevated β-catenin level, promoted its nuclear accumulation, and activated β-catenin/TCF transcription. A knockdown of E6AP lowered β-catenin levels. Coexpression with E6 intensified the activities of E6AP. Further experiments proved that E6AP/E6 stabilize β-catenin by protecting it from proteasomal degradation. This function was dependent on the catalytic activity of E6AP, the kinase activity of GSK3β and the susceptibility of β-catenin to GSK3β phosphorylation. Thus, this study identified E6AP as a novel regulator of the Wnt signaling pathway, capable of cooperating with E6 in stimulating or augmenting Wnt/β-catenin signaling, thereby possibly contributing to HPV carcinogenesis. - Highlights: • The roles of E6 and E6AP in the Wnt pathway were investigated. • E6AP stabilizes E6 and enhances E6 activity in augmentation of Wnt signaling. • E6AP cooperates with E6 to stabilize β-catenin and stimulate Wnt/β-catenin signaling. • E6AP and E6 act through different mechanisms to augment or stimulate Wnt signaling.

  15. Wnt Drug Discovery: Weaving Through the Screens, Patents and Clinical Trials

    Directory of Open Access Journals (Sweden)

    Benjamin Lu

    2016-09-01

    Full Text Available The Wnt signaling pathway is intricately involved in many aspects of development and is the root cause of an increasing number of diseases. For example, colorectal cancer is the second leading cause of death in the industrialized world and aberration of Wnt signaling within the colonic stem cell is the cause of more than 90% of these cancers. Despite our advances in successfully targeting other pathways, such as Human Epidermal Growth Factor Receptor 2 (HER2, there are no clinically relevant therapies available for Wnt-related diseases. Here, we investigated where research activities are focused with respect to Wnt signaling modulators by searching the United States Patent and Trade Office (USPTO for patents and patent applications related to Wnt modulators and compared this to clinical trials focusing on Wnt modulation. We found that while the transition of intellectual property surrounding the Wnt ligand-receptor interface to clinical trials is robust, this is not true for specific inhibitors of β-catenin, which is constitutively active in many cancers. Considering the ubiquitous use of the synthetic T-cell Factor/Lymphoid Enhancer Factor (TCF/Lef reporter system and its success in identifying novel modulators in vitro, we speculate that this model of drug discovery does not capture the complexity of in vivo Wnt signaling that may be required if we are to successfully target the Wnt pathway in the clinic. Notwithstanding, increasingly more complex models are being developed, which may not be high throughput, but more pragmatic in our pursuit to control Wnt signaling.

  16. Probable Chemical Hypoxia Effects on Progress of CNV Through Induction of Promoter CpG Demethylation and Overexpression of IL17RC in Human RPE Cells.

    Science.gov (United States)

    Alivand, Mohammad Reza; Sabouni, Farzaneh; Soheili, Zahra-Soheila

    2016-09-01

    To survey the changes of promoter CpG methylation status and mRNA expression of IL17RC (interleukin 17 receptor C) gene in retinal pigment epithelium (RPE) cells under chemical hypoxia condition for choroidal neovascularization (CNV) modeling in vitro. RPE cells were cultured in both untreated as a control group and treated by cobalt chloride media as a hypoxia group for various concentrations (100-150μM) and times (24-36 hrs.) To confirm chemical hypoxia condition, mRNA expression of HIF (Hypoxia Inducible Factor) -1α, -2α, and Vascular Endothelial Growth Factor (VEGF) was compared between two groups by Real-time PCR. Also, in normoxia and hypoxia conditions, IL17RC expression changes and promoter CpG methylation status were evaluated by Real-time PCR and methylation-specific PCR (MSP) techniques, respectively. Overexpression of HIF-1α, HIF-2α, and VEGF was significant in hypoxia versus normoxia conditions. Our data showed overexpression of IL17RC (2.1- to 6.3-fold) and decreasing of its promoter methylation in comparison with hypoxia and normoxia conditions. It was found that there are significant association between promoter methylation status and expression of IL17RC in chemical hypoxia condition. Therefore, methylation of IL17RC could play as a marker in CNV and degeneration of RPE cells in vitro. Additionally, HIF-α and methylation phenomena may be considered as critical targets for blocking in angiogenesis of age-related degeneration in future studies.

  17. Expression of angiopoietin-1 in hypoxic pericytes: Regulation by hypoxia-inducible factor-2α and participation in endothelial cell migration and tube formation.

    Science.gov (United States)

    Park, Yoon Shin; Kim, Gyungah; Jin, Yoon Mi; Lee, Jee Young; Shin, Jong Wook; Jo, Inho

    2016-01-08

    We previously reported that hypoxia increases angiopoietin-1 (Ang1), but not Ang2, mRNA expression in bovine retinal pericytes (BRP). However, the mechanism underlying Ang1 expression is unknown. Here, we report that Ang1 protein expression increased in hypoxic BRP in a dose- and time-dependent manner. This increase was accompanied by an increase in hypoxia-inducible factor-2α (HIF2α) expression. Transfection with an antisense oligonucleotide for HIF2α partially inhibited the hypoxia-induced increase in Ang1 expression. HIF2α overexpression further potentiated hypoxia-stimulated Ang1 expression, suggesting that HIF2α plays an important role in Ang1 regulation in BRP. When fused the Ang1 promoter (-3040 to +199) with the luciferase reporter gene, we found that hypoxia significantly increased promoter activity by 4.02 ± 1.68 fold. However, progressive 5'-deletions from -3040 to -1799, which deleted two putative hypoxia response elements (HRE), abolished the hypoxia-induced increase in promoter activity. An electrophoretic mobility shift assay revealed that HIF2α was predominantly bound to a HRE site, located specifically at nucleotides -2715 to -2712. Finally, treatment with conditioned medium obtained from hypoxic pericytes stimulated endothelial cell migration and tube formation, which was completely blocked by co-treatment with anti-Ang1 antibody. This study is the first to demonstrate that hypoxia upregulates Ang1 expression via HIF2α-mediated transcriptional activation in pericytes, which plays a key role in angiogenesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Cyclosporine treatment reduces oxygen free radical generation and oxidative stress in the brain of hypoxia-reoxygenated newborn piglets.

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    Richdeep S Gill

    Full Text Available Oxygen free radicals have been implicated in the pathogenesis of hypoxic-ischemic encephalopathy. It has previously been shown in traumatic brain injury animal models that treatment with cyclosporine reduces brain injury. However, the potential neuroprotective effect of cyclosporine in asphyxiated neonates has yet to be fully studied. Using an acute newborn swine model of hypoxia-reoxygenation, we evaluated the effects of cyclosporine on the brain, focusing on hydrogen peroxide (H(2O(2 production and markers of oxidative stress. Piglets (1-4 d, 1.4-2.5 kg were block-randomized into three hypoxia-reoxygenation experimental groups (2 h hypoxia followed by 4 h reoxygenation (n = 8/group. At 5 min after reoxygenation, piglets were given either i.v. saline (placebo, controls or cyclosporine (2.5 or 10 mg/kg i.v. bolus in a blinded-randomized fashion. An additional sham-operated group (n = 4 underwent no hypoxia-reoxygenation. Systemic hemodynamics, carotid arterial blood flow (transit-time ultrasonic probe, cerebral cortical H(2O(2 production (electrochemical sensor, cerebral tissue glutathione (ELISA and cytosolic cytochrome-c (western blot levels were examined. Hypoxic piglets had cardiogenic shock (cardiac output 40-48% of baseline, hypotension (mean arterial pressure 27-31 mmHg and acidosis (pH 7.04 at the end of 2 h of hypoxia. Post-resuscitation cyclosporine treatment, particularly the higher dose (10 mg/kg, significantly attenuated the increase in cortical H(2O(2 concentration during reoxygenation, and was associated with lower cerebral oxidized glutathione levels. Furthermore, cyclosporine treatment significantly attenuated the increase in cortical cytochrome-c and lactate levels. Carotid blood arterial flow was similar among groups during reoxygenation. Conclusively, post-resuscitation administration of cyclosporine significantly attenuates H(2O(2 production and minimizes oxidative stress in newborn piglets following hypoxia-reoxygenation.

  19. Analysis of the expression and function of Wnt-5a and Wnt-5b in developing and regenerating axolotl (Ambystoma mexicanum) limbs.

    Science.gov (United States)

    Ghosh, Sukla; Roy, Stéphane; Séguin, Carl; Bryant, Susan V; Gardiner, David M

    2008-05-01

    Urodele amphibians are unique adult vertebrates because they are able to regenerate body parts after amputation. Studies of urodele limb regeneration, the key model system for vertebrate regeneration, have led to an understanding of the origin of blastema cells and the importance of positional interactions between blastema cells in the control of growth and pattern formation. Progress is now being made in the identification of the signaling pathways that regulate dedifferentiation, blastema morphogenesis, growth and pattern formation. Members of the Wnt family of secreted proteins are expressed in developing and regenerating limbs, and have the potential to control growth, pattern formation and differentiation. We have studied the expression of two non-canonical Wnt genes, Wnt-5a and Wnt-5b. We report that they are expressed in equivalent patterns during limb development and limb regeneration in the axolotl (Ambystoma mexicanum), and during limb development in other tetrapods, implying conservation of function. Our analysis of the effects of ectopic Wnt-5a expression is consistent with the hypothesis that canonical Wnt signaling functions during the early stages of regeneration to control the dedifferentiation of stump cells giving rise to the regeneration-competent cells of the blastema.

  20. FOXQ1, a novel target of the Wnt pathway and a new marker for activation of Wnt signaling in solid tumors.

    Directory of Open Access Journals (Sweden)

    Jon Christensen

    Full Text Available BACKGROUND: The forkhead box transcription factor FOXQ1 has been shown to be upregulated in colorectal cancer (CRC and metastatic breast cancer and involved in tumor development, epithelial-mesenchymal transition and chemoresistance. Yet, its transcriptional regulation is still unknown. METHODS: FOXQ1 mRNA and protein expression were analysed in a panel of CRC cell lines, and laser micro-dissected human biopsy samples by qRT-PCR, microarray GeneChip® U133 Plus 2.0 and western blots. FOXQ1 regulation was assayed by chromatin immunoprecipitation and luciferase reporter assays. RESULTS: FOXQ1 was robustly induced in CRC compared to other tumors, but had no predictive value with regards to grade, metastasis and survival in CRC. Prototype-based gene coexpression and gene set enrichment analysis showed a significant association between FOXQ1 and the Wnt pathway in tumors and cancer cell lines from different tissues. In vitro experiments confirmed, on a molecular level, FOXQ1 as a direct Wnt target. Analysis of known Wnt targets identified FOXQ1 as the most suitable marker for canonical Wnt activation across a wide panel of cell lines derived from different tissues. CONCLUSIONS: Our data show that FOXQ1 is one of the most over-expressed genes in CRC and a direct target of the canonical Wnt pathway. It is a potential new marker for detection of early CRC and Wnt activation in tumors of different origins.

  1. Inhibition of calcium uptake during hypoxia in developing zebrafish is mediated by hypoxia-inducible factor.

    Science.gov (United States)

    Kwong, Raymond W M; Kumai, Yusuke; Tzaneva, Velislava; Azzi, Estelle; Hochhold, Nina; Robertson, Cayleih; Pelster, Bernd; Perry, Steve F

    2016-12-15

    The present study investigated the potential role of hypoxia-inducible factor (HIF) in calcium homeostasis in developing zebrafish (Danio rerio). It was demonstrated that zebrafish raised in hypoxic water (30 mmHg; control, 155 mmHg P O 2 ) until 4 days post-fertilization exhibited a substantial reduction in whole-body Ca 2+ levels and Ca 2+ uptake. Ca 2+ uptake in hypoxia-treated fish did not return to pre-hypoxia (control) levels within 2 h of transfer back to normoxic water. Results from real-time PCR showed that hypoxia decreased the whole-body mRNA expression levels of the epithelial Ca 2+ channel (ecac), but not plasma membrane Ca 2+ -ATPase (pmca2) or Na + /Ca 2+ -exchanger (ncx1b). Whole-mount in situ hybridization revealed that the number of ecac-expressing ionocytes was reduced in fish raised in hypoxic water. These findings suggested that hypoxic treatment suppressed the expression of ecac, thereby reducing Ca 2+ influx. To further evaluate the potential mechanisms for the effects of hypoxia on Ca 2+ regulation, a functional gene knockdown approach was employed to prevent the expression of HIF-1αb during hypoxic treatment. Consistent with a role for HIF-1αb in regulating Ca 2+ balance during hypoxia, the results demonstrated that the reduction of Ca 2+ uptake associated with hypoxic exposure was not observed in fish experiencing HIF-1αb knockdown. Additionally, the effects of hypoxia on reducing the number of ecac-expressing ionocytes was less pronounced in HIF-1αb-deficient fish. Overall, the current study revealed that hypoxic exposure inhibited Ca 2+ uptake in developing zebrafish, probably owing to HIF-1αb-mediated suppression of ecac expression. © 2016. Published by The Company of Biologists Ltd.

  2. Cycling hypoxia: A key feature of the tumor microenvironment.

    Science.gov (United States)

    Michiels, Carine; Tellier, Céline; Feron, Olivier

    2016-08-01

    A compelling body of evidence indicates that most human solid tumors contain hypoxic areas. Hypoxia is the consequence not only of the chaotic proliferation of cancer cells that places them at distance from the nearest capillary but also of the abnormal structure of the new vasculature network resulting in transient blood flow. Hence two types of hypoxia are observed in tumors: chronic and cycling (intermittent) hypoxia. Most of the current work aims at understanding the role of chronic hypoxia in tumor growth, response to treatment and metastasis. Only recently, cycling hypoxia, with spatial and temporal fluctuations in oxygen levels, has emerged as another key feature of the tumor environment that triggers different responses in comparison to chronic hypoxia. Either type of hypoxia is associated with distinct effects not only in cancer cells but also in stromal cells. In particular, cycling hypoxia has been demonstrated to favor, to a higher extent than chronic hypoxia, angiogenesis, resistance to anti-cancer treatments, intratumoral inflammation and tumor metastasis. These review details these effects as well as the signaling pathway it triggers to switch on specific transcriptomic programs. Understanding the signaling pathways through which cycling hypoxia induces these processes that support the development of an aggressive cancer could convey to the emergence of promising new cancer treatments. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Block That Pain!

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    Skip Navigation Bar Home Current Issue Past Issues Block That Pain! Past Issues / Fall 2007 Table of ... contrast, most pain relievers used for surgical procedures block activity in all types of neurons. This can ...

  4. Bundle Branch Block

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    ... known cause. Causes can include: Left bundle branch block Heart attacks (myocardial infarction) Thickened, stiffened or weakened ... myocarditis) High blood pressure (hypertension) Right bundle branch block A heart abnormality that's present at birth (congenital) — ...

  5. Ethacrynic acid exhibits selective toxicity to chronic lymphocytic leukemia cells by inhibition of the Wnt/beta-catenin pathway.

    Directory of Open Access Journals (Sweden)

    Desheng Lu

    Full Text Available BACKGROUND: Aberrant activation of Wnt/beta-catenin signaling promotes the development of several cancers. It has been demonstrated that the Wnt signaling pathway is activated in chronic lymphocytic leukemia (CLL cells, and that uncontrolled Wnt/beta-catenin signaling may contribute to the defect in apoptosis that characterizes this malignancy. Thus, the Wnt signaling pathway is an attractive candidate for developing targeted therapies for CLL. METHODOLOGY/PRINCIPAL FINDINGS: The diuretic agent ethacrynic acid (EA was identified as a Wnt inhibitor using a cell-based Wnt reporter assay. In vitro assays further confirmed the inhibitory effect of EA on Wnt/beta-catenin signaling. Cell viability assays showed that EA selectively induced cell death in primary CLL cells. Exposure of CLL cells to EA decreased the expression of Wnt/beta-catenin target genes, including LEF-1, cyclin D1 and fibronectin. Immune co-precipitation experiments demonstrated that EA could directly bind to LEF-1 protein and destabilize the LEF-1/beta-catenin complex. N-acetyl-L-cysteine (NAC, which can react with the alpha, beta-unsaturated ketone in EA, but not other anti-oxidants, prevented the drug's inhibition of Wnt/beta-catenin activation and its ability to induce apoptosis in CLL cells. CONCLUSIONS/SIGNIFICANCE: Our studies indicate that EA selectively suppresses CLL survival due to inhibition of Wnt/beta-catenin signaling. Antagonizing Wnt signaling in CLL with EA or related drugs may represent an effective treatment of this disease.

  6. Identification and expression characterization of WntA during intestinal regeneration in the sea cucumber Apostichopus japonicus.

    Science.gov (United States)

    Li, Xiaoni; Sun, Lina; Yang, Hongsheng; Zhang, Libin; Miao, Ting; Xing, Lili; Huo, Da

    2017-08-01

    Wnt genes encode secreted glycoproteins that act as signaling molecules; these molecules direct cell proliferation, migration, differentiation and survival during animal development, maintenance of homeostasis and regeneration. At present, although the regeneration mechanism in Apostichopus japonicus has been studied, there is a little research on the Wnt signaling pathway in A. japonicus. To understand the potential role of the Wnt signaling pathway in A. japonicus, we cloned and sequenced the WntA gene in A. japonicus. Protein localization analysis showed that WntA protein was ubiquitously expressed in epidermal cells, the muscle and submucosa of the intestinal tissue. After stimulation and evisceration, the dynamic changes in expression of the WntA gene and protein showed that WntA was constitutively expressed during different stages of intestine regeneration in A. japonicus, with higher levels during the early wound healing stage and late lumen formation in the residual and nascent intestinal tissues, indicating its response to intestinal regeneration. Simultaneously, cell proliferation and apoptosis analysis showed that the patterns of cell proliferation were similar to the patterns of WntA protein expression during different intestinal regeneration stages in this organism. Taken together, these results suggested that WntA might participate in intestinal regeneration and may be connected with cell proliferation, apoptosis in different intestinal layers. This research could establish a basis for further examination of WntA functions in A. japonicus and Wnt genes in other echinoderms. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. WNT10B functional dualism: beta-catenin/Tcf-dependent growth promotion or independent suppression with deregulated expression in cancer.

    Science.gov (United States)

    Yoshikawa, Hirohide; Matsubara, Kenichi; Zhou, Xiaoling; Okamura, Shu; Kubo, Takahiko; Murase, Yaeko; Shikauchi, Yuko; Esteller, Manel; Herman, James G; Wei Wang, Xin; Harris, Curtis C

    2007-11-01

    We found aberrant DNA methylation of the WNT10B promoter region in 46% of primary hepatocellular carcinoma (HCC) and 15% of colon cancer samples. Three of 10 HCC and one of two colon cancer cell lines demonstrated low or no expression, and 5-aza-2'deoxycytidine reactivated WNT10B expression with the induction of demethylation, indicating that WNT10B is silenced by DNA methylation in some cancers, whereas WNT10B expression is up-regulated in seven of the 10 HCC cell lines and a colon cancer cell line. These results indicate that WNT10B can be deregulated by either overexpression or silencing in cancer. We found that WNT10B up-regulated beta-catenin/Tcf activity. However, WNT10B-overexpressing cells demonstrated a reduced growth rate and anchorage-independent growth that is independent of the beta-catenin/Tcf activation, because mutant beta-catenin-transduced cells did not suppress growth, and dominant-negative hTcf-4 failed to alleviate the growth suppression by WNT10B. Although WNT10B expression alone inhibits cell growth, it acts synergistically with the fibroblast growth factor (FGF) to stimulate cell growth. WNT10B is bifunctional, one function of which is involved in beta-catenin/Tcf activation, and the other function is related to the down-regulation of cell growth through a different mechanism. We suggest that FGF switches WNT10B from a negative to a positive cell growth regulator.

  8. Neural Differentiation of Human Adipose Tissue-Derived Stem Cells Involves Activation of the Wnt5a/JNK Signalling

    Directory of Open Access Journals (Sweden)

    Sujeong Jang

    2015-01-01

    Full Text Available Stem cells are a powerful resource for cell-based transplantation therapies, but understanding of stem cell differentiation at the molecular level is not clear yet. We hypothesized that the Wnt pathway controls stem cell maintenance and neural differentiation. We have characterized the transcriptional expression of Wnt during the neural differentiation of hADSCs. After neural induction, the expressions of Wnt2, Wnt4, and Wnt11 were decreased, but the expression of Wnt5a was increased compared with primary hADSCs in RT-PCR analysis. In addition, the expression levels of most Fzds and LRP5/6 ligand were decreased, but not Fzd3 and Fzd5. Furthermore, Dvl1 and RYK expression levels were downregulated in NI-hADSCs. There were no changes in the expression of ß-catenin and GSK3ß. Interestingly, Wnt5a expression was highly increased in NI-hADSCs by real time RT-PCR analysis and western blot. Wnt5a level was upregulated after neural differentiation and Wnt3, Dvl2, and Naked1 levels were downregulated. Finally, we found that the JNK expression was increased after neural induction and ERK level was decreased. Thus, this study shows for the first time how a single Wnt5a ligand can activate the neural differentiation pathway through the activation of Wnt5a/JNK pathway by binding Fzd3 and Fzd5 and directing Axin/GSK-3ß in hADSCs.

  9. Frontline Science: Wnt/β-catenin pathway promotes early engraftment of fetal hematopoietic stem/progenitor cells.

    Science.gov (United States)

    Kwarteng, Edward O; Hétu-Arbour, Roxann; Heinonen, Krista M

    2018-03-01

    The switch from fetal to adult hematopoietic stem/progenitor cells (HSPCs) is associated with profound changes in several genetic programs. Although HSPC ageing corresponds to alterations in Wnt signaling, relatively little is known about the relative roles of different Wnt signaling pathways in HSPC ontogeny. We hypothesized that proliferating fetal HSPCs would be more dependent on canonical β-catenin-dependent Wnt signaling when compared to quiescent adult bone marrow HSPCs. We have compared here Wnt signaling activities in murine fetal and adult HSPCs and demonstrate a shift from Wnt/β-catenin-dependent signaling in fetal liver HSPCs to more predominantly noncanonical Wnt/polarity signaling in adult HSPCs. β-Catenin was selectively required for fetal HSPC competitiveness shortly after transplant, and protected cells from oxidative stress. Our results emphasize the complexity of Wnt signaling dynamics in HSPC maintenance and function. ©2018 Society for Leukocyte Biology.

  10. Targeting Wnt signaling in colorectal cancer. A Review in the Theme: Cell Signaling: Proteins, Pathways and Mechanisms

    Science.gov (United States)

    Novellasdemunt, Laura; Antas, Pedro

    2015-01-01

    The evolutionarily conserved Wnt signaling pathway plays essential roles during embryonic development and tissue homeostasis. Notably, comprehensive genetic studies in Drosophila and mice in the past decades have demonstrated the crucial role of Wnt signaling in intestinal stem cell maintenance by regulating proliferation, differentiation, and cell-fate decisions. Wnt signaling has also been implicated in a variety of cancers and other diseases. Loss of the Wnt pathway negative regulator adenomatous polyposis coli (APC) is the hallmark of human colorectal cancers (CRC). Recent advances in high-throughput sequencing further reveal many novel recurrent Wnt pathway mutations in addition to the well-characterized APC and β-catenin mutations in CRC. Despite attractive strategies to develop drugs for Wnt signaling, major hurdles in therapeutic intervention of the pathway persist. Here we discuss the Wnt-activating mechanisms in CRC and review the current advances and challenges in drug discovery. PMID:26289750

  11. An Lmx1b-miR135a2 regulatory circuit modulates Wnt1/Wnt signaling and determines the size of the midbrain dopaminergic progenitor pool.

    Directory of Open Access Journals (Sweden)

    Angela Anderegg

    Full Text Available MicroRNAs regulate gene expression in diverse physiological scenarios. Their role in the control of morphogen related signaling pathways has been less studied, particularly in the context of embryonic Central Nervous System (CNS development. Here, we uncover a role for microRNAs in limiting the spatiotemporal range of morphogen expression and function. Wnt1 is a key morphogen in the embryonic midbrain, and directs proliferation, survival, patterning and neurogenesis. We reveal an autoregulatory negative feedback loop between the transcription factor Lmx1b and a newly characterized microRNA, miR135a2, which modulates the extent of Wnt1/Wnt signaling and the size of the dopamine progenitor domain. Conditional gain of function studies reveal that Lmx1b promotes Wnt1/Wnt signaling, and thereby increases midbrain size and dopamine progenitor allocation. Conditional removal of Lmx1b has the opposite effect, in that expansion of the dopamine progenitor domain is severely compromised. Next, we provide evidence that microRNAs are involved in restricting dopamine progenitor allocation. Conditional loss of Dicer1 in embryonic stem cells (ESCs results in expanded Lmx1a/b+ progenitors. In contrast, forced elevation of miR135a2 during an early window in vivo phenocopies the Lmx1b conditional knockout. When En1::Cre, but not Shh::Cre or Nes::Cre, is used for recombination, the expansion of Lmx1a/b+ progenitors is selectively reduced. Bioinformatics and luciferase assay data suggests that miR135a2 targets Lmx1b and many genes in the Wnt signaling pathway, including Ccnd1, Gsk3b, and Tcf7l2. Consistent with this, we demonstrate that this mutant displays reductions in the size of the Lmx1b/Wnt1 domain and range of canonical Wnt signaling. We posit that microRNA modulation of the Lmx1b/Wnt axis in the early midbrain/isthmus could determine midbrain size and allocation of dopamine progenitors. Since canonical Wnt activity has recently been recognized as a key

  12. Psychomotor skills learning under chronic hypoxia.

    Science.gov (United States)

    Bouquet, C A; Gardette, B; Gortan, C; Abraini, J H

    1999-09-29

    Psychomotor deficits are a prominent feature in subjects exposed to hypoxia. Eight subjects exposed to chronic hypoxia during a simulated climb to 8848 m (Everest-Comex 97) were investigated using both a simple psychomotor task (Purdue pegboard) and two complex psychomotor tasks including a recognition task of either a color stimulus (high semantic level) or an abstract sign (low semantic level). Exposure to hypoxic stress mainly produced psychomotor skills learning deficits compared to control study, with greater deficits in the complex psychomotor task. The pattern of results suggests disruptions of motor strategic process. Our data further suggest that the relative strength of implicit or automatic memory processes associated with semantic information processing may increase when disturbances occur in brain functions.

  13. Hypoxia: Exposure Time Until Significant Performance Effects

    Science.gov (United States)

    2016-03-07

    three alcoholic beverages per day (on average), or were taking any prescription medication (besides oral contraceptives). Likewise, those who were...or tested positively for pregnancy were disqualified from the study, as the risks of hypoxia to a human fetus are currently unknown. Also, those...that could impact inclusion in the study. After the questionnaire, all female participants provided a urine sample for pregnancy testing. Participants

  14. NASA Gulf of Mexico Initiative Hypoxia Research

    Science.gov (United States)

    Armstrong, Curtis D.

    2012-01-01

    The Applied Science & Technology Project Office at Stennis Space Center (SSC) manages NASA's Gulf of Mexico Initiative (GOMI). Addressing short-term crises and long-term issues, GOMI participants seek to understand the environment using remote sensing, in-situ observations, laboratory analyses, field observations and computational models. New capabilities are transferred to end-users to help them make informed decisions. Some GOMI activities of interest to the hypoxia research community are highlighted.

  15. Neuroprotective Role of Intermittent Hypobaric Hypoxia in Unpredictable Chronic Mild Stress Induced Depression in Rats

    Science.gov (United States)

    Deep, Satayanarayan; Prasad, Dipti; Singh, Shashi Bala; Khan, Nilofar

    2016-01-01

    Hypoxic exposure results in several pathophysiological conditions associated with nervous system, these include acute and chronic mountain sickness, loss of memory, and high altitude cerebral edema. Previous reports have also suggested the role of hypoxia in pathogenesis of depression and related psychological conditions. On the other hand, sub lethal intermittent hypoxic exposure induces protection against future lethal hypoxia and may have beneficial effect. Therefore, the present study was designed to explore the neuroprotective role of intermittent hypobaric hypoxia (IHH) in Unpredictable Chronic Mild Stress (UCMS) induced depression like behaviour in rats. The IHH refers to the periodic exposures to hypoxic conditions interrupted by the normoxic or lesser hypoxic conditions. The current study examines the effect of IHH against UCMS induced depression, using elevated plus maze (EPM), open field test (OFT), force swim test (FST), as behavioural paradigm and related histological and molecular approaches. The data indicated the UCMS induced depression like behaviour as evident from decreased exploration activity in OFT with increased anxiety levels in EPM, and increased immobility time in the FST; whereas on providing the IHH (5000m altitude, 4hrs/day for two weeks) these behavioural changes were ameliorated. The morphological and molecular studies also validated the neuroprotective effect of IHH against UCMS induced neuronal loss and decreased neurogenesis. Here, we also explored the role of Brain-Derived Neurotrophic Factor (BDNF) in anticipatory action of IHH against detrimental effect of UCMS as upon blocking of BDNF-TrkB signalling the beneficial effect of IHH was nullified. Taken together, the findings of our study demonstrate that the intermittent hypoxia has a therapeutic potential similar to an antidepressant in animal model of depression and could be developed as a preventive therapeutic option against this pathophysiological state. PMID:26901349

  16. Neuroprotective Role of Intermittent Hypobaric Hypoxia in Unpredictable Chronic Mild Stress Induced Depression in Rats.

    Directory of Open Access Journals (Sweden)

    Neetu Kushwah

    Full Text Available Hypoxic exposure results in several pathophysiological conditions associated with nervous system, these include acute and chronic mountain sickness, loss of memory, and high altitude cerebral edema. Previous reports have also suggested the role of hypoxia in pathogenesis of depression and related psychological conditions. On the other hand, sub lethal intermittent hypoxic exposure induces protection against future lethal hypoxia and may have beneficial effect. Therefore, the present study was designed to explore the neuroprotective role of intermittent hypobaric hypoxia (IHH in Unpredictable Chronic Mild Stress (UCMS induced depression like behaviour in rats. The IHH refers to the periodic exposures to hypoxic conditions interrupted by the normoxic or lesser hypoxic conditions. The current study examines the effect of IHH against UCMS induced depression, using elevated plus maze (EPM, open field test (OFT, force swim test (FST, as behavioural paradigm and related histological and molecular approaches. The data indicated the UCMS induced depression like behaviour as evident from decreased exploration activity in OFT with increased anxiety levels in EPM, and increased immobility time in the FST; whereas on providing the IHH (5000m altitude, 4hrs/day for two weeks these behavioural changes were ameliorated. The morphological and molecular studies also validated the neuroprotective effect of IHH against UCMS induced neuronal loss and decreased neurogenesis. Here, we also explored the role of Brain-Derived Neurotrophic Factor (BDNF in anticipatory action of IHH against detrimental effect of UCMS as upon blocking of BDNF-TrkB signalling the beneficial effect of IHH was nullified. Taken together, the findings of our study demonstrate that the intermittent hypoxia has a therapeutic potential similar to an antidepressant in animal model of depression and could be developed as a preventive therapeutic option against this pathophysiological state.

  17. Hypoxia-induced hypothermia mediated by GABA in the rostral parapyramidal area of the medulla oblongata.

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    Osaka, T

    2014-05-16

    Hypoxia evokes a regulated decrease in the body core temperature (Tc) in a variety of animals. The neuronal mechanisms of this response include, at least in part, glutamatergic activation in the lateral preoptic area (LPO) of the hypothalamus. As the sympathetic premotor neurons in the medulla oblongata constitute a cardinal relay station in the descending neuronal pathway from the hypothalamus for thermoregulation, their inhibition can also be critically involved in the mechanisms of the hypoxia-induced hypothermia. Here, I examined the hypothesis that hypoxia-induced hypothermia is mediated by glutamate-responsive neurons in the LPO that activate GABAergic transmission in the rostral raphe pallidus (rRPa) and neighboring parapyramidal region (PPy) of the medulla oblongata in urethane-chloralose-anesthetized, neuromuscularly blocked, artificially ventilated rats. Unilateral microinjection of GABA (15nmol) into the rRPa and PPy regions elicited a prompt increase in tail skin temperature (Ts) and decreases in Tc, oxygen consumption rate (VO2), and heart rate. Next, when the GABAA receptor blocker bicuculline methiodide (bicuculline methiodide (BMI), 10pmol) alone was microinjected into the rRPa, it elicited unexpected contradictory responses: simultaneous increases in Ts, VO2 and heart rate and a decrease in Tc. Then, when BMI was microinjected bilaterally into the PPy, no direct effect on Ts was seen; and thermogenic and tachycardic responses were slight. However, pretreatment of the PPy with BMI, but not vehicle saline, greatly attenuated the hypothermic responses evoked by hypoxic (10%O2-90%N2, 5min) ventilation or bilateral microinjections of glutamate (5nmol, each side) into the LPO. The results suggest that hypoxia-induced hypothermia was mediated, at least in part, by the activation of GABAA receptors in the PPy. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Cytoprotective effects of fisetin against hypoxia-induced cell death in PC12 cells.

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    Chen, Pei-Yi; Ho, Yi-Ru; Wu, Ming-Jiuan; Huang, Shun-Ping; Chen, Po-Kong; Tai, Mi-Hsueh; Ho, Chi-Tang; Yen, Jui-Hung

    2015-01-01

    Fisetin (3,7,3',4'-tetrahydroxyflavone), a flavonol compound of flavonoids, exhibits a broad spectrum of biological activities including anti-oxidant, anti-inflammatory, anti-cancer and neuroprotective effects. The aim of this study is to investigate the cytoprotective effect of fisetin and the underlying molecular mechanism against hypoxia-induced cell death in PC12 cells. The results of this study showed that fisetin significantly restored the cell viability of PC12 cells under both cobalt chloride (CoCl₂)- and low oxygen-induced hypoxic conditions. Treatment with fisetin successfully reduced the CoCl₂-mediated reactive oxygen species (ROS) production, which was accompanied by an increase in the cell viability of PC12 cells. Furthermore, we found that treatment of PC12 cells with fisetin markedly upregulated hypoxia-inducible factor 1α (HIF-1α), its nuclear accumulation and the hypoxia-response element (HRE)-driven transcriptional activation. The fisetin-mediated cytoprotection during CoCl₂ exposure was significantly attenuated through the administration of HIF-1α siRNA. Moreover, we demonstrated that MAPK/ERK kinase 1/2 (MEK1/2), p38 MAPK and phosphatidylinositol 3-kinase (PI3 K) inhibitors significantly blocked the increase in cell survival that was induced by fisetin treatment under hypoxic conditions. Consistently, increased phosphorylation of ERK, p38 and Akt proteins was observed in PC12 cells treated with fisetin. However, the fisetin-induced HRE-driven transcription was not affected by inhibition of these kinase signaling pathways. Current results reveal for the first time that fisetin promotes cell survival and protects against hypoxia-induced cell death through ROS scavenging and the activation of HIF1α-, MAPK/ERK-, p38 MAPK- and PI3 K/Akt-dependent signaling pathways in PC12 cells.

  19. Inflammation Intensity-dependent Expression of Osteoinductive Wnt Proteins is Critical for Ectopic New Bone Formation in Ankylosing Spondylitis.

    Science.gov (United States)

    Li, Xiang; Wang, Jianru; Zhan, Zhongping; Li, Sibei; Zheng, Zhaomin; Wang, Taiping; Zhang, Kuibo; Pan, Hehai; Li, Zemin; Zhang, Nu; Liu, Hui

    2018-02-26

    To investigate the molecular mechanism underlying the inflammation- related ectopic new bone formation in ankylosing spondylitis (AS). Spinal tissues and sera were collected from patients or normal volunteers to detect the expression of Wnt proteins. An in vitro cell culture system mimicking the local inflammatory microenvironment of bone-forming sites was established to study the relationship between inflammation and Wnt expression, the regulatory mechanism of inflammation-induced Wnt expression and the role of Wnt signaling in new bone formation. A modified collagen-induced arthritis (mCIA) and a proteoglycan -induced spondylitis (PGIS) animal model were used to confirm the key findings in vivo. The levels of osteoinductive Wnt proteins were obviously increased in the sera and spinal ligament tissues of patients with AS. Only constitutive low-intensity TNF-α stimulation, but not short-term or high-intensity TNF-α stimulation, induced persistent expression of osteoinductive Wnt proteins and subsequent bone formation through NF-κB (p65) and JNK/AP-1 (c-Jun) signaling pathways. Furthermore, inhibition of either Wnt/β-catenin or Wnt/PKCδ pathway significantly suppressed new bone formation. The increased expression of Wnt proteins was confirmed in both mCIA and PGIS models. A kyphotic and ankylosing phenotype of the spine was observed during long-term observation in mCIA model. Inhibition of either Wnt/β-catenin or Wnt/PKCδ signaling pathway significantly reduced the incidence and severity of this phenotype. Inflammation intensity-dependent expression of osteoinductive Wnt proteins is a key link between inflammation and ectopic new bone formation in AS. Activation of both canonical Wnt/β-catenin and noncanonical Wnt/PKCδ pathways is required for inflammation-induced new bone formation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. Wnt-10b secreted from lymphocytes promotes differentiation of skin epithelial cells

    International Nuclear Information System (INIS)

    Ouji, Yukiteru; Yoshikawa, Masahide; Shiroi, Akira; Ishizaka, Shigeaki

    2006-01-01

    Wnt-10b was originally isolated from lymphoid tissue and is known to be involved in a wide range of biological actions, while recently it was found to be expressed early in the development of hair follicles. However, few studies have been conducted concerning the role of Wnt-10b with the differentiation of skin epithelial cells. To evaluate its role in epithelial differentiation, we purified Wnt-10b from the supernatant of a concanavalin A-stimulated lymphocyte culture using an affinity column and investigated its effects on the differentiation of adult mouse-derived primary skin epithelial cells (MPSEC). MPSEC cultured with Wnt-10b showed morphological changes from cuboidal to spindle-shaped with inhibited proliferation, and also obtained characteristics of the hair shaft and inner root sheath of the hair follicle, represented by red-colored Ayoub Shklar staining, and reactions to AE-13 and AE-15 as seen with immunocytology. Further, RT-PCR analysis demonstrated the expression of mRNA for keratin 1, keratin 2, loricrin, mHa5, and mHb5, in association with a decreased expression of the basal cell marker keratin 5, in Wnt-10b-treated MPSEC. In addition, involvement of the canonical Wnt signal pathway was demonstrated by a TCF reporter (pTOPFLASH) assay. These results suggest that Wnt-10b promotes the differentiation of MPSEC and may play an important role in hair follicle development by promoting differentiation of epithelial cells

  1. Wnt1 inhibits hydrogen peroxide-induced apoptosis in mouse cardiac stem cells.

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    Jingjin Liu

    Full Text Available BACKGROUND: Because of their regenerative and paracrine abilities, cardiac stem cells (CSCs are the most appropriate, optimal and promising candidates for the development of cardiac regenerative medicine strategies. However, native and exogenous CSCs in ischemic hearts are exposed to various pro-apoptotic or cytotoxic factors preventing their regenerative and paracrine abilities. METHODS AND RESULTS: We examined the effects of H2O2 on mouse CSCs (mCSCs, and observed that hydrogen peroxide (H2O2 treatment induces mCSCs apoptosis via the caspase 3 pathway, in a dose-dependent manner. We then examined the effects of Wnt1 over-expression on H2O2-induced apoptosis in mCSCs and observed that Wnt1 significantly decreased H2O2-induced apoptosis in mCSCs. On the other hand, inhibition of the canonical Wnt pathway by the secreted frizzled related protein 2 (SFRP2 or knockdown of β-catenin in mCSCs reduced cells resistance to H2O2-induced apoptosis, suggesting that Wnt1 predominantly prevents H2O2-induced apoptosis through the canonical Wnt pathway. CONCLUSIONS: Our results provide the first evidences that Wnt1 plays an important role in CSCs' defenses against H2O2-induced apoptosis through the canonical Wnt1/GSK3β/β-catenin signaling pathway.

  2. Deregulated WNT signaling in childhood T-cell acute lymphoblastic leukemia

    International Nuclear Information System (INIS)

    Ng, O H; Erbilgin, Y; Firtina, S; Celkan, T; Karakas, Z; Aydogan, G; Turkkan, E; Yildirmak, Y; Timur, C; Zengin, E; Dongen, J J M van; Staal, F J T; Ozbek, U; Sayitoglu, M

    2014-01-01

    WNT signaling has been implicated in the regulation of hematopoietic stem cells and plays an important role during T-cell development in thymus. Here we investigated WNT pathway activation in childhood T-cell acute lymphoblastic leukemia (T-ALL) patients. To evaluate the potential role of WNT signaling in T-cell leukomogenesis, we performed expression analysis of key components of WNT pathway. More than 85% of the childhood T-ALL patients showed upregulated β-catenin expression at the protein level compared with normal human thymocytes. The impact of this upregulation was reflected in high expression of known target genes (AXIN2, c-MYC, TCF1 and LEF). Especially AXIN2, the universal target gene of WNT pathway, was upregulated at both mRNA and protein levels in ∼40% of the patients. When β-CATENIN gene was silenced by small interfering RNA, the cancer cells showed higher rates of apoptosis. These results demonstrate that abnormal WNT signaling activation occurs in a significant fraction of human T-ALL cases independent of known T-ALL risk factors. We conclude that deregulated WNT signaling is a novel oncogenic event in childhood T-ALL

  3. Apcdd1 is a novel Wnt inhibitor Mutated in Hereditary Hypotrichosis Simplex

    Science.gov (United States)

    Shimomura, Yutaka; Agalliu, Dritan; Vonica, Alin; Luria, Victor; Wajid, Muhammad; Baumer, Alessandra; Belli, Serena; Petukhova, Lynn; Schinzel, Albert; Brivanlou, Ali H.; Barres, Ben A.; Christiano, Angela M.

    2011-01-01

    Hereditary hypotrichosis simplex (HHS) is a rare autosomal dominant form of hair loss characterized by hair follicle (HF) miniaturization1, 2. Using genetic linkage analysis, we mapped a novel locus for HHS to chromosome 18p11.22, and identified a mutation (L9R) in the APCDD1 gene in three families. We show that APCDD1 is a membrane-bound glycoprotein that is abundantly expressed in human HFs, and can interact in vitro with WNT3A and LRP5, two essential components of Wnt signaling. Functional studies revealed that APCDD1 inhibits Wnt signaling in a cell-autonomous manner and functions upstream of β-catenin. Moreover, APCDD1 represses activation of Wnt reporters and target genes, and inhibits the biological effects of Wnt signaling during both the generation of neurons from progenitors in the developing chick nervous system, and axis specification in Xenopus embryos. The mutation L9R is located in the signal peptide of APCDD1, and perturbs its translational processing from ER to the plasma membrane. L9R-APCDD1 likely functions in a dominant-negative manner to inhibit the stability and membrane localization of the wild-type protein. These findings describe a novel inhibitor of the Wnt signaling pathway with an essential role in human hair growth. Since APCDD1 is expressed in a broad repertoire of cell types3, our findings suggest that APCDD1 may regulate a diversity of biological processes controlled by Wnt signaling. PMID:20393562

  4. To Wnt or Lose: The Missing Non-Coding Linc in Colorectal Cancer.

    Science.gov (United States)

    Shen, Peng; Pichler, Martin; Chen, Meng; Calin, George A; Ling, Hui

    2017-09-20

    Colorectal cancer (CRC) is the third most frequent cancer and one of the leading causes for cancer-related mortality. Aberrant activation of the Wnt signaling is an essential initiating factor in colon carcinogenesis, and a driving force of CRC progression. Recently, long non-coding RNAs (lncRNAs) have emerged as significant players in CRC pathogenesis through diversified mechanisms. Although both Wnt signaling and lncRNAs represent interesting research areas for CRC, an effort of directly connecting these two areas is lacking. To fill in the knowledge gap, we focus on the reported findings of lncRNAs that regulate Wnt signaling or essential Wnt signaling targets. These include several newly discovered lncRNAs originated from the amplified cancer-associated chromosome 8q24 region that surrounds the essential Wnt target MYC gene, lncRNAs reported to be involved in CRC stem cells, and several individual lncRNAs connected to Wnt signaling through other mechanisms. This review will provide essential information that assists in understanding the missing link of lncRNAs to the classical Wnt signaling in CRC.

  5. Timing is everything: Reiterative Wnt, BMP and RA signaling regulate developmental competence during endoderm organogenesis.

    Science.gov (United States)

    Rankin, Scott A; McCracken, Kyle W; Luedeke, David M; Han, Lu; Wells, James M; Shannon, John M; Zorn, Aaron M

    2018-02-01

    A small number of signaling pathways are used repeatedly during organogenesis, and they can have drastically different effects on the same population of cells depending on the embryonic stage. How cellular competence changes over developmental time is not well understood. Here we used Xenopus, mouse, and human pluripotent stem cells to investigate how the temporal sequence of Wnt, BMP, and retinoic acid (RA) signals regulates endoderm developmental competence and organ induction, focusing on respiratory fate. While Nkx2-1+ lung fate is not induced until late somitogenesis stages, here we show that lung competence is restricted by the gastrula stage as a result of Wnt and BMP-dependent anterior-posterior (A-P) patterning. These early Wnt and BMP signals make posterior endoderm refractory to subsequent RA/Wnt/BMP-dependent lung induction. We further mapped how RA modulates the response to Wnt and BMP in a temporal specific manner. In the gastrula RA promotes posterior identity, however in early somite stages of development RA regulates respiratory versus pharyngeal potential in anterior endoderm and midgut versus hindgut potential in posterior endoderm. Together our data suggest a dynamic and conserved response of vertebrate endoderm during organogenesis, wherein early Wnt/BMP/RA impacts how cells respond to later Wnt/BMP/RA signals, illustrating how reiterative combinatorial signaling can regulate both developmental competence and subsequent fate specification. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Small Molecules Inspired by the Natural Product Withanolides as Potent Inhibitors of Wnt Signaling.

    Science.gov (United States)

    Sheremet, Michael; Kapoor, Shobhna; Schröder, Peter; Kumar, Kamal; Ziegler, Slava; Waldmann, Herbert

    2017-09-19

    Wnt signaling is a fundamental pathway that drives embryonic development and is essential for stem cell maintenance and tissue homeostasis. Dysregulation of Wnt signaling is linked to various diseases, and a constitutively active Wnt pathway drives tumorigenesis. Thus, disruption of the Wnt response is deemed a promising strategy for cancer drug discovery. However, only few clinical drug candidates that target Wnt signaling are available so far, and new small-molecule modulators of Wnt-related processes are in high demand. Here we describe the synthesis of small molecules inspired by withanolide natural products by using a pregnenolone-derived β-lactone as the key intermediate that was transformed into a δ-lactone appended to the D-ring of the steroidal scaffold. This natural-product-inspired compound library contained potent inhibitors of Wnt signaling that act upstream of the destruction complex to stabilize Axin in a tankyrase-independent manner. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Small-molecule Wnt agonists correct cleft palates in Pax9 mutant mice in utero.

    Science.gov (United States)

    Jia, Shihai; Zhou, Jing; Fanelli, Christopher; Wee, Yinshen; Bonds, John; Schneider, Pascal; Mues, Gabriele; D'Souza, Rena N

    2017-10-15

    Clefts of the palate and/or lip are among the most common human craniofacial malformations and involve multiple genetic and environmental factors. Defects can only be corrected surgically and require complex life-long treatments. Our studies utilized the well-characterized Pax9 -/- mouse model with a consistent cleft palate phenotype to test small-molecule Wnt agonist therapies. We show that the absence of Pax9 alters the expression of Wnt pathway genes including Dkk1 and Dkk2 , proven antagonists of Wnt signaling. The functional interactions between Pax9 and Dkk1 are shown by the genetic rescue of secondary palate clefts in Pax9 -/- Dkk1 f/+ ;Wnt1Cre embryos. The controlled intravenous delivery of small-molecule Wnt agonists (Dkk inhibitors) into pregnant Pax9 +/- mice restored Wnt signaling and led to the growth and fusion of palatal shelves, as marked by an increase in cell proliferation and osteogenesis in utero , while other organ defects were not corrected. This work underscores the importance of Pax9-dependent Wnt signaling in palatogenesis and suggests that this functional upstream molecular relationship can be exploited for the development of therapies for human cleft palates that arise from single-gene disorders. © 2017. Published by The Company of Biologists Ltd.

  8. Emerging Role and Therapeutic Implication of Wnt Signaling Pathways in Autoimmune Diseases

    Science.gov (United States)

    Shi, Juan; Chi, Shuhong; Xue, Jing; Yang, Jiali; Li, Feng; Liu, Xiaoming

    2016-01-01

    The Wnt signaling pathway plays a key role in many biological aspects, such as cellular proliferation, tissue regeneration, embryonic development, and other systemic effects. Under a physiological condition, it is tightly controlled at different layers and arrays, and a dysregulated activation of this signaling has been implicated into the pathogenesis of various human disorders, including autoimmune diseases. Despite the fact that therapeutic interventions are available for ameliorating disease manifestations, there is no curative therapy currently available for autoimmune disorders. Increasing lines of evidence have suggested a crucial role of Wnt signaling during the pathogenesis of many autoimmune diseases; in addition, some of microRNAs (miRNAs), a class of small, noncoding RNA molecules capable of transcriptionally regulating gene expression, have also recently been demonstrated to possess both physiological and pathological roles in autoimmune diseases by regulating the Wnt signaling pathway. This review summarizes currently our understanding of the pathogenic roles of Wnt signaling in several major autoimmune disorders and miRNAs, those targeting Wnt signaling in autoimmune diseases, with a focus on the implication of the Wnt signaling as potential biomarkers and therapeutic targets in immune diseases, as well as miRNA-mediated regulation of Wnt signaling activation in the development of autoimmune diseases. PMID:27110577

  9. Role of the Wnt receptor Frizzled-1 in presynaptic differentiation and function

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    Alvarez Alejandra R

    2009-11-01

    Full Text Available Abstract Background The Wnt signaling pathway regulates several fundamental developmental processes and recently has been shown to be involved in different aspects of synaptic differentiation and plasticity. Some Wnt signaling components are localized at central synapses, and it is thus possible that this pathway could be activated at the synapse. Results We examined the distribution of the Wnt receptor Frizzled-1 in cultured hippocampal neurons and determined that this receptor is located at synaptic contacts co-localizing with presynaptic proteins. Frizzled-1 was found in functional synapses detected with FM1-43 staining and in synaptic terminals from adult rat brain. Interestingly, overexpression of Frizzled-1 increased the number of clusters of Bassoon, a component of the active zone, while treatment with the extracellular cysteine-rich domain (CRD of Frizzled-1 decreased Bassoon clustering, suggesting a role for this receptor in presynaptic differentiation. Consistent with this, treatment with the Frizzled-1 ligand Wnt-3a induced presynaptic protein clustering and increased functional presynaptic recycling sites, and these effects were prevented by co-treatment with the CRD of Frizzled-1. Moreover, in synaptically mature neurons Wnt-3a was able to modulate the kinetics of neurotransmitter release. Conclusion Our results indicate that the activation of the Wnt pathway through Frizzled-1 occurs at the presynaptic level, and suggest that the synaptic effects of the Wnt signaling pathway could be modulated by local activation through synaptic Frizzled receptors.

  10. Roles of ADAM13-regulated Wnt activity in early Xenopus eye development

    Science.gov (United States)

    Wei, Shuo; Xu, Guofeng; Bridges, Lance C.; Williams, Phoebe; Nakayama, Takuya; Shah, Anoop; Grainger, Robert M.; White, Judith M.; DeSimone, Douglas W.

    2012-01-01

    Pericellular proteolysis by ADAM family metalloproteinases has been widely implicated in cell signaling and development. We recently found that Xenopus ADAM13, an ADAM metalloproteinase, is required for activation of canonical Wnt signaling during cranial neural crest (CNC) induction by regulating a novel crosstalk between Wnt and ephrin B (EfnB) signaling pathways (Wei et al., 2010b). In the present study we show that the metalloproteinase activity of ADAM13 also plays important roles in eye development in X. tropicalis. Knockdown of ADAM13 results in reduced expression of eye field markers pax6 and rx1, as well as that of the pan-neural marker sox2. Activation of canonical Wnt signaling or inhibition of forward EfnB signaling rescues the eye defects caused by loss of ADAM13, suggesting that ADAM13 functions through regulation of the EfnB-Wnt pathway interaction. Downstream of Wnt, the head inducer Cerberus was identified as an effector that mediates ADAM13 function in early eye field formation. Furthermore, ectopic expression of the Wnt target gene snail2 restores cerberus expression and rescues the eye defects caused by ADAM13 knockdown. Together these data suggest an important role of ADAM13-regulated Wnt activity in eye development in Xenopus. PMID:22227340

  11. Butyrate and bioactive proteolytic form of Wnt-5a regulate colonic epithelial proliferation and spatial development

    Science.gov (United States)

    Uchiyama, Kazuhiko; Sakiyama, Toshio; Hasebe, Takumu; Musch, Mark W.; Miyoshi, Hiroyuki; Nakagawa, Yasushi; He, Tong-Chuan; Lichtenstein, Lev; Naito, Yuji; Itoh, Yoshito; Yoshikawa, Toshikazu; Jabri, Bana; Stappenbeck, Thaddeus; Chang, Eugene B.

    2016-01-01

    Proliferation and spatial development of colonic epithelial cells are highly regulated along the crypt vertical axis, which, when perturbed, can result in aberrant growth and carcinogenesis. In this study, two key factors were identified that have important and counterbalancing roles regulating these processes: pericrypt myofibroblast-derived Wnt-5a and the microbial metabolite butyrate. Cultured YAMC cell proliferation and heat shock protein induction were analzyed after butryate, conditioned medium with Wnt5a activity, and FrzB containing conditioned medium. In vivo studies to modulate Hsp25 employed intra-colonic wall Hsp25 encoding lentivirus. To silence Wnt-5a in vivo, intra-colonic wall Wnt-5a silencing RNA was used. Wnt-5a, secreted by stromal myofibroblasts of the lower crypt, promotes proliferation through canonical β-catenin activation. Essential to this are two key requirements: (1) proteolytic conversion of the highly insoluble ~40 kD Wnt-5a protein to a soluble 36 mer amino acid peptide that activates epithelial β-catenin and cellular proliferation, and (2) the simultaneous inhibition of butyrate-induced Hsp25 by Wnt-5a which is necessary to arrest the proliferative process in the upper colonic crypt. The interplay and spatial gradients of these factors insures that crypt epithelial cell proliferation and development proceed in an orderly fashion, but with sufficient plasticity to adapt to physiological perturbations including inflammation. PMID:27561676

  12. Emerging Role and Therapeutic Implication of Wnt Signaling Pathways in Autoimmune Diseases

    Directory of Open Access Journals (Sweden)

    Juan Shi

    2016-01-01

    Full Text Available The Wnt signaling pathway plays a key role in many biological aspects, such as cellular proliferation, tissue regeneration, embryonic development, and other systemic effects. Under a physiological condition, it is tightly controlled at different layers and arrays, and a dysregulated activation of this signaling has been implicated into the pathogenesis of various human disorders, including autoimmune diseases. Despite the fact that therapeutic interventions are available for ameliorating disease manifestations, there is no curative therapy currently available for autoimmune disorders. Increasing lines of evidence have suggested a crucial role of Wnt signaling during the pathogenesis of many autoimmune diseases; in addition, some of microRNAs (miRNAs, a class of small, noncoding RNA molecules capable of transcriptionally regulating gene expression, have also recently been demonstrated to possess both physiological and pathological roles in autoimmune diseases by regulating the Wnt signaling pathway. This review summarizes currently our understanding of the pathogenic roles of Wnt signaling in several major autoimmune disorders and miRNAs, those targeting Wnt signaling in autoimmune diseases, with a focus on the implication of the Wnt signaling as potential biomarkers and therapeutic targets in immune diseases, as well as miRNA-mediated regulation of Wnt signaling activation in the development of autoimmune diseases.

  13. Fgf9 and Wnt4 act as antagonistic signals to regulate mammalian sex determination.

    Directory of Open Access Journals (Sweden)

    Yuna Kim

    2006-06-01

    Full Text Available The genes encoding members of the wingless-related MMTV integration site (WNT and fibroblast growth factor (FGF families coordinate growth, morphogenesis, and differentiation in many fields of cells during development. In the mouse, Fgf9 and Wnt4 are expressed in gonads of both sexes prior to sex determination. Loss of Fgf9 leads to XY sex reversal, whereas loss of Wnt4 results in partial testis development in XX gonads. However, the relationship between these signals and the male sex-determining gene, Sry, was unknown. We show through gain- and loss-of-function experiments that fibroblast growth factor 9 (FGF9 and WNT4 act as opposing signals to regulate sex determination. In the mouse XY gonad, Sry normally initiates a feed-forward loop between Sox9 and Fgf9, which up-regulates Fgf9 and represses Wnt4 to establish the testis pathway. Surprisingly, loss of Wnt4 in XX gonads is sufficient to up-regulate Fgf9 and Sox9 in the absence of Sry. These data suggest that the fate of the gonad is controlled by antagonism between Fgf9 and Wnt4. The role of the male sex-determining switch--Sry in the case of mammals--is to tip the balance between these underlying patterning signals. In principle, sex determination in other vertebrates may operate through any switch that introduces an imbalance between these two signaling pathways.

  14. Novel applications of trophic factors, Wnt and WISP for neuronal repair and regeneration in metabolic disease

    Directory of Open Access Journals (Sweden)

    Kenneth Maiese

    2015-01-01

    Full Text Available Diabetes mellitus affects almost 350 million individuals throughout the globe resulting in significant morbidity and mortality. Of further concern is the growing population of individuals that remain undiagnosed but are susceptible to the detrimental outcomes of this disorder. Diabetes mellitus leads to multiple complications in the central and peripheral nervous systems that include cognitive impairment, retinal disease, neuropsychiatric disease, cerebral ischemia, and peripheral nerve degeneration. Although multiple strategies are being considered, novel targeting of trophic factors, Wnt signaling, Wnt1 inducible signaling pathway protein 1, and stem cell tissue regeneration are considered to be exciting prospects to overcome the cellular mechanisms that lead to neuronal injury in diabetes mellitus involving oxidative stress, apoptosis, and autophagy. Pathways that involve insulin-like growth factor-1, fibroblast growth factor, epidermal growth factor, and erythropoietin can govern glucose homeostasis and are intimately tied to Wnt signaling that involves Wnt1 and Wnt1 inducible signaling pathway protein 1 (CCN4 to foster control over stem cell proliferation, wound repair, cognitive decline,β-cell proliferation, vascular regeneration, and programmed cell death. Ultimately, cellular metabolism through Wnt signaling is driven by primary metabolic pathways of the mechanistic target of rapamycin and AMP activated protein kinase. These pathways offer precise biological control of cellular metabolism, but are exquisitely sensitive to the different components of Wnt signaling. As a result, unexpected clinical outcomes can ensue and therefore demand careful translation of the mechanisms that govern neural repair and regeneration in diabetes mellitus.

  15. Wnt target genes and where to find them [version 1; referees: 3 approved

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    Aravinda-Bharathi Ramakrishnan

    2017-05-01

    Full Text Available Wnt/β-catenin signaling is highly conserved throughout metazoans, is required for numerous essential events in development, and serves as a stem cell niche signal in many contexts. Misregulation of the pathway is linked to several human pathologies, most notably cancer. Wnt stimulation results in stabilization and nuclear import of β-catenin, which then acts as a transcriptional co-activator. Transcription factors of the T-cell family (TCF are the best-characterized nuclear binding partners of β-catenin and mediators of Wnt gene regulation. This review provides an update on what is known about the transcriptional activation of Wnt target genes, highlighting recent work that modifies the conventional model. Wnt/β-catenin signaling regulates genes in a highly context-dependent manner, and the role of other signaling pathways and TCF co-factors in this process will be discussed. Understanding Wnt gene regulation has served to elucidate many biological roles of the pathway, and we will use examples from stem cell biology, metabolism, and evolution to illustrate some of the rich Wnt biology that has been uncovered.

  16. Optical imaging of tumor hypoxia dynamics

    Science.gov (United States)

    Palmer, Gregory M.; Fontanella, Andrew N.; Zhang, Guoqing; Hanna, Gabi; Fraser, Cassandra L.; Dewhirst, Mark W.

    2010-11-01

    The influence of the tumor microenvironment and hypoxia plays a significant role in determining cancer progression, treatment response, and treatment resistance. That the tumor microenvironment is highly heterogeneous with significant intratumor and intertumor variability presents a significant challenge in developing effective cancer therapies. Critical to understanding the role of the tumor microenvironment is the ability to dynamically quantify oxygen levels in the vasculature and tissue in order to elucidate the roles of oxygen supply and consumption, spatially and temporally. To this end, we describe the use of hyperspectral imaging to characterize hemoglobin absorption to quantify hemoglobin content and oxygen saturation, as well as dual emissive fluorescent/phosphorescent boron nanoparticles, which serve as ratiometric indicators of tissue oxygen tension. Applying these techniques to a window-chamber tumor model illustrates the role of fluctuations in hemoglobin saturation in driving changes in tissue oxygenation, the two being significantly correlated (r = 0.77). Finally, a green-fluorescence-protein reporter for hypoxia inducible factor-1 (HIF-1) provides an endpoint for hypoxic stress in the tumor, which is used to demonstrate a significant association between tumor hypoxia dynamics and HIF-1 activity in an in vivo demonstration of the technique.

  17. Hypoxia in the changing marine environment

    International Nuclear Information System (INIS)

    Zhang, J; Cowie, G; Naqvi, S W A

    2013-01-01

    The predicted future of the global marine environment, as a combined result of forcing due to climate change (e.g. warming and acidification) and other anthropogenic perturbation (e.g. eutrophication), presents a challenge to the sustainability of ecosystems from tropics to high latitudes. Among the various associated phenomena of ecosystem deterioration, hypoxia can cause serious problems in coastal areas as well as oxygen minimum zones in the open ocean (Diaz and Rosenberg 2008 Science 321 926–9, Stramma et al 2008 Science 320 655–8). The negative impacts of hypoxia include changes in populations of marine organisms, such as large-scale mortality and behavioral responses, as well as variations of species distributions, biodiversity, physiological stress, and other sub-lethal effects (e.g. growth and reproduction). Social and economic activities that are related to services provided by the marine ecosystems, such as tourism and fisheries, can be negatively affected by the aesthetic outcomes as well as perceived or real impacts on seafood quality (STAP 2011 (Washington, DC: Global Environment Facility) p 88). Moreover, low oxygen concentration in marine waters can have considerable feedbacks to other compartments of the Earth system, like the emission of greenhouse gases to the atmosphere, and can affect the global biogeochemical cycles of nutrients and trace elements. It is of critical importance to prediction and adaptation strategies that the key processes of hypoxia in marine environments be precisely determined and understood (cf Zhang et al 2010 Biogeosciences 7 1–24). (synthesis and review)

  18. Hypoxia in the changing marine environment

    Science.gov (United States)

    Zhang, J.; Cowie, G.; Naqvi, S. W. A.

    2013-03-01

    The predicted future of the global marine environment, as a combined result of forcing due to climate change (e.g. warming and acidification) and other anthropogenic perturbation (e.g. eutrophication), presents a challenge to the sustainability of ecosystems from tropics to high latitudes. Among the various associated phenomena of ecosystem deterioration, hypoxia can cause serious problems in coastal areas as well as oxygen minimum zones in the open ocean (Diaz and Rosenberg 2008 Science 321 926-9, Stramma et al 2008 Science 320 655-8). The negative impacts of hypoxia include changes in populations of marine organisms, such as large-scale mortality and behavioral responses, as well as variations of species distributions, biodiversity, physiological stress, and other sub-lethal effects (e.g. growth and reproduction). Social and economic activities that are related to services provided by the marine ecosystems, such as tourism and fisheries, can be negatively affected by the aesthetic outcomes as well as perceived or real impacts on seafood quality (STAP 2011 (Washington, DC: Global Environment Facility) p 88). Moreover, low oxygen concentration in marine waters can have considerable feedbacks to other compartments of the Earth system, like the emission of greenhouse gases to the atmosphere, and can affect the global biogeochemical cycles of nutrients and trace elements. It is of critical importance to prediction and adaptation strategies that the key processes of hypoxia in marine environments be precisely determined and understood (cf Zhang et al 2010 Biogeosciences 7 1-24).

  19. Intrauterine hypoxia: clinical consequences and therapeutic perspectives

    Directory of Open Access Journals (Sweden)

    Thompson LP

    2015-09-01

    Full Text Available Loren P Thompson,1 Sarah Crimmins,1 Bhanu P Telugu,2 Shifa Turan1 1Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA; 2Department of Animal Sciences, University of Maryland, College Park, MD, USA Abstract: Intrauterine hypoxia is a significant clinical challenge in obstetrics that affects both the pregnant mother and fetus. Intrauterine hypoxia can occur in pregnant women living at high altitude and/or with cardiovascular disease. In addition, placental hypoxia can be generated by altered placental development and spiral artery remodeling leading to placental insufficiency and dysfunction. Both conditions can impact normal maternal cardiovascular homeostasis leading to preeclampsia and/or impair transfer of O2/nutrient supply resulting in fetal growth restriction. This review discusses the mechanisms underlying altered placental vessel remodeling, maternal and fetal consequences, patient management, and potential future therapies for improving these conditions. Keywords: fetal growth restriction, oxidative stress, extravillous trophoblast invasion, Doppler ultrasound, pulsatility index, preeclampsia 

  20. Generalized Block Failure

    DEFF Research Database (Denmark)

    Jönsson, Jeppe

    2015-01-01

    Block tearing is considered in several codes as a pure block tension or a pure block shear failure mechanism. However in many situations the load acts eccentrically and involves the transfer of a substantial moment in combination with the shear force and perhaps a normal force. A literature study...... shows that no readily available tests with a well-defined substantial eccentricity have been performed. This paper presents theoretical and experimental work leading towards generalized block failure capacity methods. Simple combination of normal force, shear force and moment stress distributions along...... yield lines around the block leads to simple interaction formulas similar to other interaction formulas in the codes....

  1. Enhanced chondrogenesis and Wnt signaling in PTH-treated fractures.

    Science.gov (United States)

    Kakar, Sanjeev; Einhorn, Thomas A; Vora, Siddharth; Miara, Lincoln J; Hon, Gregory; Wigner, Nathan A; Toben, Daniel; Jacobsen, Kimberly A; Al-Sebaei, Maisa O; Song, Michael; Trackman, Philip C; Morgan, Elise F; Gerstenfeld, Louis C; Barnes, George L

    2007-12-01

    Studies have shown that systemic PTH treatment enhanced the rate of bone repair in rodent models. However, the mechanisms through which PTH affects bone repair have not been elucidated. In these studies we show that PTH primarily enhanced the earliest stages of endochondral bone repair by increasing chondrocyte recruitment and rate of differentiation. In coordination with these cellular events, we observed an increased level of canonical Wnt-signaling in PTH-treated bones at multiple time-points across the time-course of fracture repair, supporting the conclusion that PTH responses are at least in part mediated through Wnt signaling. Since FDA approval of PTH [PTH(1-34); Forteo] as a treatment for osteoporosis, there has been interest in its use in other musculoskeletal conditions. Fracture repair is one area in which PTH may have a significant clinical impact. Multiple animal studies have shown that systemic PTH treatment of healing fractures increased both callus volume and return of mechanical competence in models of fracture healing. Whereas the potential for PTH has been established, the mechanism(s) by which PTH produces these effects remain elusive. Closed femoral fractures were generated in 8-wk-old male C57Bl/6 mice followed by daily systemic injections of either saline (control) or 30 microg/kg PTH(1-34) for 14 days after fracture. Bones were harvested at days 2, 3, 5, 7, 10, 14, 21, and 28 after fracture and analyzed at the tissue level by radiography and histomorphometry and at the molecular and biochemical levels level by RNase protection assay (RPA), real-time PCR, and Western blot analysis. Quantitative muCT analysis showed that PTH treatment induced a larger callus cross-sectional area, length, and total volume compared with controls. Molecular analysis of the expression of extracellular matrix genes associated with chondrogenesis and osteogenesis showed that PTH treated fractures displayed a 3-fold greater increase in chondrogenesis relative to

  2. Ubiquitination is absolutely required for the degradation of hypoxia-inducible factor - 1 alpha protein in hypoxic conditions

    International Nuclear Information System (INIS)

    Wang, Ronghai; Zhang, Ping; Li, Jinhang; Guan, Hongzai; Shi, Guangjun

    2016-01-01

    The hypoxia-inducible factor (HIF) is recognized as the master regulator of hypoxia response. HIF-α subunits expression are tightly regulated. In this study, our data show that ts20 cells still expressed detectable E1 protein even at 39.5° C for 12 h, and complete depletion of E1 protein expression at 39.5° C by siRNA enhanced HIF-1α and P53 protein expression. Further inhibition of E1 at 39.5 °C by siRNA, or E1 inhibitor Ube1-41 completely blocked HIF-1α degradation. Moreover, immunoprecipitations of co-transfection of HA-ubiquitin and FLAG–HIF–1α plasmids directly confirmed the involvement of ubiquitin in the hypoxic degradation of HIF-1α. Additionally, hypoxic HIF-1 α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization. Taken together, our data suggest that constitutive HIF-1α protein degradation in hypoxia is absolutely ubiquitination-dependent, and unidentified E3 ligase may exist for this degradation pathway. - Highlights: • HIF-1α protein is constitutively degraded in hypoxic conditions. • Requirement of ubiquitination for HIF-1α degradation in hypoxia. • Hypoxic HIF-1α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization.

  3. Ubiquitination is absolutely required for the degradation of hypoxia-inducible factor - 1 alpha protein in hypoxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ronghai [Department of Urology, Linzi District People' s Hospital, Zibo, 255400 (China); Zhang, Ping, E-mail: zpskx001@163.com [Department of Gynecology, Qingdao Municipal Hospital, Qingdao, 266011 (China); Li, Jinhang [Department of Gynecology, Qingdao Municipal Hospital, Qingdao, 266011 (China); Guan, Hongzai [Laboratory Department, School of Medicine, Qingdao University, Qingdao, 266071 (China); Shi, Guangjun, E-mail: qdmhshigj@yahoo.com [Department of Hepatobiliary Surgery, Qingdao Municipal Hospital, Qingdao, 266071 (China)

    2016-01-29

    The hypoxia-inducible factor (HIF) is recognized as the master regulator of hypoxia response. HIF-α subunits expression are tightly regulated. In this study, our data show that ts20 cells still expressed detectable E1 protein even at 39.5° C for 12 h, and complete depletion of E1 protein expression at 39.5° C by siRNA enhanced HIF-1α and P53 protein expression. Further inhibition of E1 at 39.5 °C by siRNA, or E1 inhibitor Ube1-41 completely blocked HIF-1α degradation. Moreover, immunoprecipitations of co-transfection of HA-ubiquitin and FLAG–HIF–1α plasmids directly confirmed the involvement of ubiquitin in the hypoxic degradation of HIF-1α. Additionally, hypoxic HIF-1 α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization. Taken together, our data suggest that constitutive HIF-1α protein degradation in hypoxia is absolutely ubiquitination-dependent, and unidentified E3 ligase may exist for this degradation pathway. - Highlights: • HIF-1α protein is constitutively degraded in hypoxic conditions. • Requirement of ubiquitination for HIF-1α degradation in hypoxia. • Hypoxic HIF-1α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization.

  4. Hypoxia-inducible factor-1 plays a role in phosphate-induced vascular smooth muscle cell calcification.

    Science.gov (United States)

    Mokas, Sophie; Larivière, Richard; Lamalice, Laurent; Gobeil, Stéphane; Cornfield, David N; Agharazii, Mohsen; Richard, Darren E

    2016-09-01

    Medial vascular calcification is a common complication of chronic kidney disease (CKD). Although elevated inorganic phosphate stimulates vascular smooth muscle cell (VSMC) osteogenic transdifferentiation and calcification, the mechanisms involved in their calcification during CKD are not fully defined. Because hypoxic gene activation is linked to CKD and stimulates bone cell osteogenic differentiation, we used in vivo and in vitro rodent models to define the role of hypoxic signaling during elevated inorganic phosphate-induced VSMC calcification. Cell mineralization studies showed that elevated inorganic phosphate rapidly induced VSMC calcification. Hypoxia strongly enhanced elevated inorganic phosphate-induced VSMC calcification and osteogenic transdifferentiation, as seen by osteogenic marker expression. Hypoxia-inducible factor-1 (HIF-1), the key hypoxic transcription factor, was essential for enhanced VSMC calcification. Targeting HIF-1 expression in murine VSMC blocked calcification in hypoxia with elevated inorganic phosphate while HIF-1 activators, including clinically used FG-4592/Roxadustat, recreated a procalcifying environment. Elevated inorganic phosphate rapidly activated HIF-1, even in normal oxygenation; an effect mediated by HIF-1α subunit stabilization. Thus, hypoxia synergizes with elevated inorganic phosphate to enhance VSMC osteogenic transdifferentiation. Our work identifies HIF-1 as an early CKD-related pathological event, prospective marker, and potential target against vascular calcification in CKD-relevant conditions. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  5. Hypoxia symptoms during altitude training in professional Iranian fighter pilots.

    Science.gov (United States)

    Alagha, Babak; AhmadBeygi, Shervin; Ahmadbeigy, Shervin; Moosavi, Seyed Ali Javad; Jalali, Seyed Mahmood

    2012-01-01

    Susceptibility to hypoxia is influenced by a multitude of factors, including fatigue, physical activity, illnesses, ambient temperature, rate of ascent, destination altitude, medications, and alcohol. Anecdotally, several reports have been made regarding changes in the form of hypoxia presentation in Iranian fighter pilots in the absence of these factors. This study focused specifically on the effect of pilot age on susceptibility to hypoxia and its initial presentation. We assumed that a pilot's age may increase his susceptibility to hypoxia and consequently reduce the amount of time it takes for hypoxia to present. Because our literature review did not reveal any previous study addressing the possible relationship between age and susceptibility to hypoxia, the purpose of this study is to address and clarify this relationship. In this retrospective study, we collected information from Iranian fighter pilots (n = 30) through an anonymous questionnaire in 2000. The form of hypoxia presentation of each subject was evaluated during five altitude chamber training (ACT) sessions that were conducted routinely from 1972 to 1984. To enhance the accuracy of the study's results, confounding factors such as prior hypoxia experience in an ACT session have been taken into consideration. The results revealed a statistically significant relationship between age and a change in the form of hypoxia presentation in our subjects. Increased age reduced the amount of time before the first individual hypoxia symptom appeared (P < .000002). Although having previous hypoxia experience may help pilots to recognize their symptoms earlier, its effect was not statistically significant (P < .18). A few changes in the nature of individual symptoms were observed; however, we did not find a meaningful statistical correlation between pilot age and change in the nature of symptoms. Susceptibility ot hypoxia increases with pilot age. Copyright © 2012 Air Medical Journal Associates. Published by

  6. Endogenous markers of tumor hypoxia. Predictors of clinical radiation resistance?

    International Nuclear Information System (INIS)

    Vordermark, D.; Brown, J.M.

    2003-01-01

    Background: Eppendorf electrode measurements of tumor oxygenation have defined an adverse effect of tumor hypoxia on prognosis after radiotherapy and other treatment modalities, in particular in head and neck and cervix carcinomas as well as soft tissue sarcomas. Recently, the immunohistochemical detection of proteins involved in the ''hypoxic response'' of tumor cells has been discussed as a method to estimate hypoxia in clinical tumor specimens. Material and Methods: This review focuses on clinical and experimental data, regarding prognostic impact and comparability with other methods of hypoxia detection, for three proteins suggested as endogenous markers of tumor hypoxia: hypoxia-inducible factor-1α (HIF-1α), carbonic anhydrase 9 (CA 9), and glucose transporter 1 (GLUT1). Results: None of the three potential hypoxia markers is exclusively hypoxia-specific, and in each case protein can be detected under normoxic conditions in vitro. HIF-1α responds rapidly to hypoxia but also to reoxygenation, making this marker quite unstable in the context of clinical sample collection. The perinecrotic labeling pattern typical of chronic hypoxia and a reasonable agreement with injectable hypoxia markers such as pimonidazole have most consistently been described for CA 9. All three markers showed correlation with Eppendorf electrode measurements of tumor oxygenation in carcinoma of the cervix. In nine of 13 reports, among them all three that refer to curative radiotherapy for head and neck cancer, HIF-1α overexpression was associated with poor outcome. CA 9 was an adverse prognostic factor in cervix, head and neck and lung cancer, but not in two other head and neck cancer reports. GLUT1 predicted for poor survival in colorectal, cervix and lung cancer. Conclusion: Endogenous markers have the potential to indicate therapeutically relevant levels of hypoxia within tumors. Clinical trials assessing a marker's ability to predict a benefit from specific hypoxia

  7. Discovery and characterization of a potent Wnt and hedgehog signaling pathways dual inhibitor.

    Science.gov (United States)

    Ma, Haikuo; Chen, Qin; Zhu, Fang; Zheng, Jiyue; Li, Jiajun; Zhang, Hongjian; Chen, Shuaishuai; Xing, Haimei; Luo, Lusong; Zheng, Long Tai; He, Sudan; Zhang, Xiaohu

    2018-04-10

    Embryonic stem cell pathways such as hedgehog and Wnt pathways are central to the tumorigenic properties of cancer stem cells (CSC). Since CSCs are characterized by their ability to self-renew, form differentiated progeny, and develop resistance to anticancer therapies, targeting the Wnt and hedgehog signaling pathways has been an important strategy for cancer treatment. Although molecules targeting either Wnt or hedgehog are common, to the best of our knowledge, those targeting both pathways have not been documented. Here we report a small molecule (compound 1) that inhibits both Wnt (IC 50  = 0.5 nM) and hedgehog (IC 50  = 71 nM) pathways based on reporter gene assays. We further identified that the molecular target of 1 for Wnt pathway inhibition was porcupine (a member of the membrane-bound O-acyltransferase family of proteins), a post-translational modification node in Wnt signaling; while the target of 1 mitigating hedgehog pathway was Smoothened, a key G protein coupled receptor (GPCR) mediating hedgehog signal transduction. Preliminary analysis of structure-activity-relationship identified key functional elements for hedgehog/Wnt inhibition. In in vivo studies, compound 1 demonstrated good oral exposure and bioavailability while eliciting no overt toxicity in mice. An important consideration in cancer treatment is the potential therapeutic escape through compensatory activation of an interconnected pathway when only one signaling pathway is inhibited. Toward this end, compound 1 may not only lead to the development of new therapeutics for Wnt and hedgehog related cancers, but may also help to develop potential cancer treatment which needs to target Wnt and hedgehog signaling simultaneously. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  8. Inhibition of Wnt Signaling Pathways Impairs Chlamydia trachomatis Infection in Endometrial Epithelial Cells.

    Science.gov (United States)

    Kintner, Jennifer; Moore, Cheryl G; Whittimore, Judy D; Butler, Megan; Hall, Jennifer V

    2017-01-01

    Chlamydia trachomatis infections represent the predominant cause of bacterial sexually transmitted infections. As an obligate intracellular bacterium, C. trachomatis is dependent on the host cell for survival, propagation, and transmission. Thus, factors that affect the host cell, including nutrition, cell cycle, and environmental signals, have the potential to impact chlamydial development. Previous studies have demonstrated that activation of Wnt/β-catenin signaling benefits C. trachomatis infections in fallopian tube epithelia. In cervical epithelial cells chlamydiae sequester β-catenin within the inclusion. These data indicate that chlamydiae interact with the Wnt signaling pathway in both the upper and lower female genital tract (FGT). However, hormonal activation of canonical and non-canonical Wnt signaling pathways is an essential component of cyclic remodeling in another prominent area of the FGT, the endometrium. Given this information, we hypothesized that Wnt signaling would impact chlamydial infection in endometrial epithelial cells. To investigate this hypothesis, we analyzed the effect of Wnt inhibition on chlamydial inclusion development and elementary body (EB) production in two endometrial cell lines, Ishikawa (IK) and Hec-1B, in nonpolarized cell culture and in a polarized endometrial epithelial (IK)/stromal (SHT-290) cell co-culture model. Inhibition of Wnt by the small molecule inhibitor (IWP2) significantly decreased inclusion size in IK and IK/SHT-290 cultures ( p Wnt inhibition caused chlamydiae to become aberrant in morphology. EB formation was also impaired in IK, Hec-1B and IK/SHT-290 cultures regardless of whether Wnt inhibition occurred throughout, in the middle (24 hpi) or late (36 hpi) during the development cycle. Overall, these data lead us to conclude that Wnt signaling in the endometrium is a key host pathway for the proper development of C. trachomatis .

  9. Human placental trophoblast invasion and differentiation: a particular focus on Wnt signalling

    Directory of Open Access Journals (Sweden)

    Martin eKnöfler

    2013-09-01

    Full Text Available Wingless ligands, a family of secreted proteins, are critically involved in organ development and tissue homeostasis by ensuring balanced rates of stem cell proliferation, cell death and differentiation. Wnt signalling components also play crucial roles in murine placental development controlling trophoblast lineage determination, chorioallantoic fusion and placental branching morphogenesis. However, the role of the pathway in human placentation, trophoblast development and differentiation is only partly understood. Here, we summarize our present knowledge about Wnt signalling in the human placenta and discuss its potential role in physiological and aberrant trophoblast invasion, gestational diseases and choriocarcinoma formation. Differentiation of proliferative first trimester cytotrophoblasts into invasive extravillous trophoblasts is associated with nuclear recruitment of β-catenin and induction of Wnt-dependent T-cell factor 4 suggesting that canonical Wnt signalling could be important for the formation and function of extravillous trophoblasts. Indeed, activation of the pathway was shown to promote trophoblast invasion in different in vitro trophoblast model systems as well as trophoblast cell fusion. Methylation-mediated silencing of inhibitors of Wnt signalling provided evidence for epigenetic activation of the pathway in placental tissues and choriocarcinoma cells. Similarly, abundant nuclear expression of β-catenin in invasive trophoblasts of complete hydatidiform moles suggested a role for hyper-activated Wnt signalling. In contrast, upregulation of Wnt inhibitors was noticed in placentae of women with preeclampsia, a disease characterized by shallow trophoblast invasion and incomplete spiral artery remodelling. Moreover, changes in Wnt signalling have been observed upon cytomegalovirus infection and in recurrent abortions. In summary, the current literature suggests a critical role of Wnt signalling in physiological and abnormal

  10. Epigenetic mediated transcriptional activation of WNT5A participates in arsenical-associated malignant transformation

    International Nuclear Information System (INIS)

    Jensen, Taylor J.; Wozniak, Ryan J.; Eblin, Kylee E.; Wnek, Sean M.; Gandolfi, A. Jay; Futscher, Bernard W.

    2009-01-01

    Arsenic is a human carcinogen with exposure associated with cancer of the lung, skin, and bladder. Many potential mechanisms have been implicated as playing a role in the process of arsenical-induced malignancy including the perturbation of signaling pathways and aberrant epigenetic regulation. We initiated studies to examine the role of a member of the non-canonical WNT signaling pathway, WNT5A, in UROtsa cells and arsenite [URO-ASSC] and monomethylarsonous acid [URO-MSC] malignantly transformed variants. We present data herein that suggest that WNT5A is transcriptionally activated during arsenical-induced malignant transformation. This WNT5A transcriptional activation is correlated with the enrichment of permissive histone modifications and the reduction of repressive modifications in the WNT5A promoter region. The epigenetic activation of WNT5A expression and acetylation of its promoter remain after the removal of the arsenical, consistent with the maintenance of an anchorage independent growth phenotype in these cells. Additionally, treatment with epigenetic modifying drugs supports a functional role for these epigenetic marks in controlling gene expression. Reduction of WNT5A using lentiviral shRNA greatly attenuated the ability of these cells to grow in an anchorage independent fashion. Extension of our model into human bladder cancer cell lines indicates that each of the cell lines examined also express WNT5A. Taken together, these data suggest that the epigenetic remodeling of the WNT5A promoter is correlated with its transcriptional activation and this upregulation likely participates in arsenical-induced malignant transformation

  11. Endothelial Dysfunction in Human Diabetes Is Mediated by Wnt5a-JNK Signaling.

    Science.gov (United States)

    Bretón-Romero, Rosa; Feng, Bihua; Holbrook, Monika; Farb, Melissa G; Fetterman, Jessica L; Linder, Erika A; Berk, Brittany D; Masaki, Nobuyuki; Weisbrod, Robert M; Inagaki, Elica; Gokce, Noyan; Fuster, Jose J; Walsh, Kenneth; Hamburg, Naomi M

    2016-03-01

    Endothelial dysfunction is linked to insulin resistance, inflammatory activation, and increased cardiovascular risk in diabetes mellitus; however, the mechanisms remain incompletely understood. Recent studies have identified proinflammatory signaling of wingless-type family member (Wnt) 5a through c-jun N-terminal kinase (JNK) as a regulator of metabolic dysfunction with potential relevance to vascular function. We sought to gain evidence that increased activation of Wnt5a-JNK signaling contributes to impaired endothelial function in patients with diabetes mellitus. We measured flow-mediated dilation of the brachial artery and characterized freshly isolated endothelial cells by protein expression, eNOS activation, and nitric oxide production in 85 subjects with type 2 diabetes mellitus (n=42) and age- and sex-matched nondiabetic controls (n=43) and in human aortic endothelial cells treated with Wnt5a. Endothelial cells from patients with diabetes mellitus displayed 1.3-fold higher Wnt5a levels (P=0.01) along with 1.4-fold higher JNK activation (P<0.01) without a difference in total JNK levels. Higher JNK activation was associated with lower flow-mediated dilation, consistent with endothelial dysfunction (r=0.53, P=0.02). Inhibition of Wnt5a and JNK signaling restored insulin and A23187-mediated eNOS activation and improved nitric oxide production in endothelial cells from patients with diabetes mellitus. In endothelial cells from nondiabetic controls, rWnt5a treatment inhibited eNOS activation replicating the diabetic endothelial phenotype. In human aortic endothelial cells, Wnt5a-induced impairment of eNOS activation and nitric oxide production was reversed by Wnt5a and JNK inhibition. Our findings demonstrate that noncanonical Wnt5a signaling and JNK activity contribute to vascular insulin resistance and endothelial dysfunction and may represent a novel therapeutic opportunity to protect the vasculature in patients with diabetes mellitus. © 2016 American Heart

  12. Tissue hypoxia during ischemic stroke: adaptive clues from hypoxia-tolerant animal models.

    Science.gov (United States)

    Nathaniel, Thomas I; Williams-Hernandez, Ashley; Hunter, Anan L; Liddy, Caroline; Peffley, Dennis M; Umesiri, Francis E; Imeh-Nathaniel, Adebobola

    2015-05-01

    The treatment and prevention of hypoxic/ischemic brain injury in stroke patients remain a severe and global medical issue. Numerous clinical studies have resulted in a failure to develop chemical neuroprotection for acute, ischemic stroke. Over 150 estimated clinical trials of ischemic stroke treatments have been done, and more than 200 drugs and combinations of drugs for ischemic and hemorrhagic strokes have been developed. Billions of dollars have been invested for new scientific breakthroughs with only limited success. The revascularization of occluded cerebral arteries such as anti-clot treatments of thrombolysis has proven effective, but it can only be used in a 3-4.5h time frame after the onset of a stroke, and not for every patient. This review is about novel insights on how to resist tissue hypoxia from unconventional animal models. Ability to resist tissue hypoxia is an extraordinary ability that is not common in many laboratory animals such as rat and mouse models. For example, we can learn from a naked mole-rat, Chrysemys picta, how to actively regulate brain metabolic activity to defend the brain against fluctuating oxygen tension and acute bouts of oxidative stress following the onset of a stroke. Additionally, a euthermic arctic ground squirrel can teach us how the brain of a stroke patient can remain well oxygenated during tissue hypoxia with no evidence of cellular stress. In this review, we discuss how these animals provide us with a system to gain insight into the possible mechanisms of tissue hypoxia/ischemia. This issue is of clinical significance to stroke patients. We describe specific physiological and molecular adaptations employed by different animals' models of hypoxia tolerance in aquatic and terrestrial environments. We highlight how these adaptations might provide potential clues on strategies to adapt for the clinical management of tissue hypoxia during conditions such as stroke where oxygen demand fails to match the supply. Copyright

  13. Cognitive responses to hypobaric hypoxia: implications for aviation training

    Directory of Open Access Journals (Sweden)

    Neuhaus C

    2014-11-01

    Full Text Available Christopher Neuhaus,1,2 Jochen Hinkelbein2,31Department of Anesthesiology, Heidelberg University Hospital, Ruprecht Karls University of Heidelberg, Heidelberg, 2Emergency Medicine and Air Rescue Working Group, German Society of Aviation and Space Medicine (DGLRM, Munich, 3Department of Anesthesiology and Intensive Care Medicine, University Hospital of Cologne, Cologne, GermanyAbstract: The aim of this narrative review is to provide an overview on cognitive responses to hypobaric hypoxia and to show relevant implications for aviation training. A principal element of hypoxia-awareness training is the intentional evocation of hypoxia symptoms during specific training sessions within a safe and controlled environment. Repetitive training should enable pilots to learn and recognize their personal hypoxia symptoms. A time span of 3–6 years is generally considered suitable to refresh knowledge of the more subtle and early symptoms especially. Currently, there are two different technical approaches available to induce hypoxia during training: hypobaric chamber training and reduced-oxygen breathing devices. Hypoxia training for aircrew is extremely important and effective, and the hypoxia symptoms should be emphasized clearly to aircrews. The use of tight-fitting masks, leak checks, and equipment checks should be taught to all aircrew and reinforced regularly. It is noteworthy that there are major differences in the required quality and quantity of hypoxia training for both military and civilian pilots.Keywords: cognitive response, aviation training, pilot, hypoxia, oxygen, loss of consciousness

  14. Wnt/β-catenin Signaling in Normal and Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Kenneth C. Valkenburg

    2011-04-01

    Full Text Available The ability of Wnt ligands to initiate a signaling cascade that results in cytoplasmic stabilization of, and nuclear localization of, β-catenin underlies their ability to regulate progenitor cell differentiation. In this review, we will summarize the current knowledge of the mechanisms underlying Wnt/β-catenin signaling and how the pathway regulates normal differentiation of stem cells in the intestine, mammary gland, and prostate. We will also discuss how dysregulation of the pathway is associated with putative cancer stem cells and the potential therapeutic implications of regulating Wnt signaling.

  15. Rubinstein-Taybi syndrome predisposing to non-WNT, non-SHH, group 3 medulloblastoma.

    Science.gov (United States)

    Bourdeaut, Franck; Miquel, Catherine; Richer, Wilfrid; Grill, Jacques; Zerah, Michel; Grison, Camille; Pierron, Gaelle; Amiel, Jeanne; Krucker, Clementine; Radvanyi, Francois; Brugieres, Laurence; Delattre, Olivier

    2014-02-01

    Medulloblastomas (MB) are classified in four subgroups: the well defined WNT and Sonic Hedgehog (SHH) subgroups, and the less defined groups 3 and 4. They occasionally occur in the context of a cancer predisposition syndrome. While germline APC mutations predispose to WNT MB, germline mutations in SUFU, PTCH1, and TP53 predispose to SHH tumors. We report on a child with a Rubinstein-Taybi syndrome (RTS) due to a germline deletion in CREBBP, who developed a MB. Biological profilings demonstrate that this tumor belongs to the group 3. RTS may therefore be the first predisposition syndrome identified for non-WNT/non-SHH MB. © 2013 Wiley Periodicals, Inc.

  16. WNT and DKK Determine Hair Follicle Spacing Through a Reaction-Diffusion Mechanism

    Science.gov (United States)

    Sick, Stefanie; Reinker, Stefan; Timmer, Jens; Schlake, Thomas

    2006-12-01

    Mathematical reaction-diffusion models have been suggested to describe formation of animal pigmentation patterns and distribution of epidermal appendages. However, the crucial signals and in vivo mechanisms are still elusive. Here we identify WNT and its inhibitor DKK as primary determinants of murine hair follicle spacing, using a combined experimental and computational modeling approach. Transgenic DKK overexpression reduces overall appendage density. Moderate suppression of endogenous WNT signaling forces follicles to form clusters during an otherwise normal morphogenetic program. These results confirm predictions of a WNT/DKK-specific mathematical model and provide in vivo corroboration of the reaction-diffusion mechanism for epidermal appendage formation.

  17. Blocked Randomization with Randomly Selected Block Sizes

    Directory of Open Access Journals (Sweden)

    Jimmy Efird

    2010-12-01

    Full Text Available When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes.

  18. Developmental Hypoxia Has Negligible Effects on Long-Term Hypoxia Tolerance and Aerobic Metabolism of Atlantic Salmon (Salmo salar).

    Science.gov (United States)

    Wood, Andrew T; Clark, Timothy D; Andrewartha, Sarah J; Elliott, Nicholas G; Frappell, Peter B

    Exposure to developmental hypoxia can have long-term impacts on the physiological performance of fish because of irreversible plasticity. Wild and captive-reared Atlantic salmon (Salmo salar) can be exposed to hypoxic conditions during development and continue to experience fluctuating oxygen levels as juveniles and adults. Here, we examine whether developmental hypoxia impacts subsequent hypoxia tolerance and aerobic performance of Atlantic salmon. Individuals at 8°C were exposed to 50% (hypoxia) or 100% (normoxia) dissolved oxygen (DO) saturation (as percent of air saturation) from fertilization for ∼100 d (800 degree days) and then raised in normoxic conditions for a further 15 mo. At 18 mo after fertilization, aerobic scope was calculated in normoxia (100% DO) and acute (18 h) hypoxia (50% DO) from the difference between the minimum and maximum oxygen consumption rates ([Formula: see text] and [Formula: see text], respectively) at 10°C. Hypoxia tolerance was determined as the DO at which loss of equilibrium (LOE) occurred in a constantly decreasing DO environment. There was no difference in [Formula: see text], [Formula: see text], or aerobic scope between fish raised in hypoxia or normoxia. There was some evidence that hypoxia tolerance was lower (higher DO at LOE) in hypoxia-raised fish compared with those raised in normoxia, but the magnitude of the effect was small (12.52% DO vs. 11.73% DO at LOE). Acute hypoxia significantly reduced aerobic scope by reducing [Formula: see text], while [Formula: see text] remained unchanged. Interestingly, acute hypoxia uncovered individual-level relationships between DO at LOE and [Formula: see text], [Formula: see text], and aerobic scope. We discuss our findings in the context of developmental trajectories and the role of aerobic performance in hypoxia tolerance.

  19. 31 CFR 595.301 - Blocked account; blocked property.

    Science.gov (United States)

    2010-07-01

    ... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY TERRORISM SANCTIONS REGULATIONS General Definitions § 595.301 Blocked account; blocked property. The terms blocked account and blocked...

  20. Activation and Inhibition of The Wnt3A Signaling Pathway in Buffalo (Bubalus bubalis Embryonic Stem Cells: Effects of WNT3A, Bio and Dkk1

    Directory of Open Access Journals (Sweden)

    Mohammad Zandi

    2015-07-01

    Full Text Available Background: This research studies the effects of activation and inhibition of Wnt3A signaling pathway in buffalo (Bubalus bubalis embryonic stem (ES cell-like cells. Materials and Methods: To carry on this experimental study, the effects of activation and inhibition of Wnt3A signaling in buffalo ES cell-like cells were examined using Bio (0.5 mM combined with WNT3A (200 ng/ml, as an activator, and Dickkopf-1 (Dkk1, 250 ng/ml, as an inhibitor, of the pathway. ES cells were cultured up to three weeks in ES cell medium without fibroblast growth factor-2 (FGF-2 and leukemia inhibitory factor (LIF, but in the presence of Bio, WNT3A, Bio+WNT3A and Dkk1. The effects of these supplements were measured on the mean area of ES cell colonies and on the expression levels of a number of important genes related to pluripotency (Oct4, Nanog, Sox2 and c-Myc and the Wnt pathway (β-catenin. ES cell colonies cultured in ES cell medium that contained optimized quantities of LIF and FGF-2 were used as the control. Data were collected for week-1 and week-3 treated cultures. In addition, WNT3A-transfected ES cells were compared with the respective mock-transfected colonies, either alone or in combination with Dkk1 for expression of β-catenin and the pluripotency-related genes. Data were analyzed by ANOVA, and statistical significance was accepted at P<0.05. Results: Among various examined concentrations of Bio (0.5-5 mM, the optimum effect was observed at the 0.5 mM dose as indicated by colony area and expressions of pluripotency- related genes at both weeks-1 and -3 culture periods. At this concentration,the expressions of Nanog, Oct3/4, Sox2, c-Myc and β-catenin genes were nonsignificantly higher compared to the controls. Expressions of these genes were highest in the Bio+WNT3A treated group, followed by the WNT3A and Bio-supplemented groups, and lowest in the Dkk1-treated group. The WNT-transfected colonies showed higher expressions compared to both mock and Dkk1

  1. A Wnt5 Activity Asymmetry and Intercellular Signaling via PCP Proteins Polarize Node Cells for Left-Right Symmetry Breaking.

    Science.gov (United States)

    Minegishi, Katsura; Hashimoto, Masakazu; Ajima, Rieko; Takaoka, Katsuyoshi; Shinohara, Kyosuke; Ikawa, Yayoi; Nishimura, Hiromi; McMahon, Andrew P; Willert, Karl; Okada, Yasushi; Sasaki, Hiroshi; Shi, Dongbo; Fujimori, Toshihiko; Ohtsuka, Toshihisa; Igarashi, Yasunobu; Yamaguchi, Terry P; Shimono, Akihiko; Shiratori, Hidetaka; Hamada, Hiroshi

    2017-03-13

    Polarization of node cells along the anterior-posterior axis of mouse embryos is responsible for left-right symmetry breaking. How node cells become polarized has remained unknown, however. Wnt5a and Wnt5b are expressed posteriorly relative to the node, whereas genes for Sfrp inhibitors of Wnt signaling are expressed anteriorly. Here we show that polarization of node cells is impaired in Wnt5a -/- Wnt5b -/- and Sfrp mutant embryos, and also in the presence of a uniform distribution of Wnt5a or Sfrp1, suggesting that Wnt5 and Sfrp proteins act as instructive signals in this process. The absence of planar cell polarity (PCP) core proteins Prickle1 and Prickle2 in individual cells or local forced expression of Wnt5a perturbed polarization of neighboring wild-type cells. Our results suggest that opposing gradients of Wnt5a and Wnt5b and of their Sfrp inhibitors, together with intercellular signaling via PCP proteins, polarize node cells along the anterior-posterior axis for breaking of left-right symmetry. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Noncanonical Wnt signaling promotes obesity-induced adipose tissue inflammation and metabolic dysfunction independent of adipose tissue expansion.

    Science.gov (United States)

    Fuster, José J; Zuriaga, María A; Ngo, Doan Thi-Minh; Farb, Melissa G; Aprahamian, Tamar; Yamaguchi, Terry P; Gokce, Noyan; Walsh, Kenneth

    2015-04-01

    Adipose tissue dysfunction plays a pivotal role in the development of insulin resistance in obese individuals. Cell culture studies and gain-of-function mouse models suggest that canonical Wnt proteins modulate adipose tissue expansion. However, no genetic evidence supports a role for endogenous Wnt proteins in adipose tissue dysfunction, and the role of noncanonical Wnt signaling remains largely unexplored. Here we provide evidence from human, mouse, and cell culture studies showing that Wnt5a-mediated, noncanonical Wnt signaling contributes to obesity-associated metabolic dysfunction by increasing adipose tissue inflammation. Wnt5a expression is significantly upregulated in human visceral fat compared with subcutaneous fat in obese individuals. In obese mice, Wnt5a ablation ameliorates insulin resistance, in parallel with reductions in adipose tissue inflammation. Conversely, Wnt5a overexpression in myeloid cells augments adipose tissue inflammation and leads to greater impairments in glucose homeostasis. Wnt5a ablation or overexpression did not affect fat mass or adipocyte size. Mechanistically, Wnt5a promotes the expression of proinflammatory cytokines by macrophages in a Jun NH2-terminal kinase-dependent manner, leading to defective insulin signaling in adipocytes. Exogenous interleukin-6 administration restores insulin resistance in obese Wnt5a-deficient mice, suggesting a central role for this cytokine in Wnt5a-mediated metabolic dysfunction. Taken together, these results demonstrate that noncanonical Wnt signaling contributes to obesity-induced insulin resistance independent of adipose tissue expansion. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  3. Block Cipher Analysis

    DEFF Research Database (Denmark)

    Miolane, Charlotte Vikkelsø

    ensurethat no attack violatesthe securitybounds specifiedbygeneric attack namely exhaustivekey search and table lookup attacks. This thesis contains a general introduction to cryptography with focus on block ciphers and important block cipher designs, in particular the Advanced Encryption Standard(AES...... on small scale variants of AES. In the final part of the thesis we present a new block cipher proposal Present and examine its security against algebraic and differential cryptanalysis in particular....

  4. The zebrafish miR-462/miR-731 cluster is induced under hypoxic stress via hypoxia-inducible factor 1α and functions in cellular adaptations.

    Science.gov (United States)

    Huang, Chun-Xiao; Chen, Nan; Wu, Xin-Jie; Huang, Cui-Hong; He, Yan; Tang, Rong; Wang, Wei-Min; Wang, Huan-Ling

    2015-12-01

    Hypoxia, a unique and essential environmental stress, evokes highly coordinated cellular responses, and hypoxia-inducible factor (HIF) 1 in the hypoxia signaling pathway, an evolutionarily conserved cellular signaling pathway, acts as a master regulator of the transcriptional response to hypoxic stress. MicroRNAs (miRNAs), a major class of posttranscriptional gene expression regulators, also play pivotal roles in orchestrating hypoxia-mediated cellular adaptations. Here, global miRNA expression profiling and quantitative real-time PCR indicated that the up-regulation of the miR-462/miR-731 cluster in zebrafish larvae is induced by hypoxia. It was further validated that miR-462 and miR-731 are up-regulated in a Hif-1α-mediated manner under hypoxia and specifically target ddx5 and ppm1da, respectively. Overexpression of miR-462 and miR-731 represses cell proliferation through blocking cell cycle progress of DNA replication, and induces apoptosis. In situ detection revealed that the miR-462/miR-731 cluster is highly expressed in a consistent and ubiquitous manner throughout the early developmental stages. Additionally, the transcripts become restricted to the notochord, pharyngeal arch, liver, and gut regions from postfertilization d 3 to 5. These data highlight a previously unidentified role of the miR-462/miR-731 cluster as a crucial signaling mediator for hypoxia-mediated cellular adaptations and provide some insights into the potential function of the cluster during embryonic development. © FASEB.