scholarly journals Multiple signaling pathways involved in stimulation of osteoblast differentiation by N-methyl-D-aspartate receptors activation in vitro

2011 ◽  
Vol 32 (7) ◽  
pp. 895-903 ◽  
Author(s):  
Jie-li Li ◽  
Lin Zhao ◽  
Bin Cui ◽  
Lian-fu Deng ◽  
Guang Ning ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Osteoblast Differentiation ◽  
Multiple Signaling ◽  
Stimulation Of

scholarly journals Multiple Signaling Pathways Converge on the Cbfa1/Runx2 Transcription Factor to Regulate Osteoblast Differentiation

2003 ◽  
Vol 44 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Renny Franceschi ◽  
Guozhi Xiao ◽  
Di Jiang ◽  
Rajaram Gopalakrishnan ◽  
Shuying Yang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Signaling Pathways ◽  
Osteoblast Differentiation ◽  
Multiple Signaling

scholarly journals Acid Stimulation of the Citrate Transporter NaDC-1 Requires Pyk2 and ERK1/2 Signaling Pathways

2018 ◽  
Vol 29 (6) ◽  
pp. 1720-1730 ◽  
Author(s):  
Miriam Zacchia ◽  
Xuefei Tian ◽  
Enrica Zona ◽  
Robert J. Alpern ◽  
Patricia A. Preisig
Keyword(s):  
Proximal Tubule ◽  
Signaling Pathways ◽  
Cultured Cells ◽  
Wild Type ◽  
Experimental Conditions ◽  
Opossum Kidney ◽  
Citrate Transporter ◽  
Stimulation Of

Background Urine citrate is reabsorbed exclusively along the renal proximal tubule via the apical Na+-dicarboxylate cotransporter NaDC-1. We previously showed that an acid load in vivo and media acidification in vitro increase NaDC-1 activity through endothelin-1 (ET-1)/endothelin B (ETB) signaling. Here, we further examined the signaling pathway mediating acid-induced NaDC-1 activity.Methods We transiently transfected cultured opossum kidney cells, a model of the proximal tubule, with NaDC-1 and ETB and measured [14C]-citrate uptake after media acidification under various experimental conditions, including inactivation of Pyk2 and c-Src, which were previously shown to be activated by media acidification. Wild-type (Pyk2+/+) and Pyk2-null (Pyk2−/−) mice were exposed to NH4Cl loading and euthanized after various end points, at which time we harvested the kidneys for immunoblotting and brush border membrane NaDC-1 activity studies.Results Inhibition of Pyk2 or c-Src prevented acid stimulation but not ET-1 stimulation of NaDC-1 in vitro. Consistent with these results, NH4Cl loading stimulated NaDC-1 activity in kidneys of wild-type but not Pyk2−/− mice. In cultured cells and in mice, ERK1/2 was rapidly phosphorylated by acid loading, even after Pyk2 knockdown, and it was required for acid but not ET-1/ETB stimulation of NaDC-1 in vitro. Media acidification also induced the phosphorylation of Raf1 and p90RSK, components of the ERK1/2 pathway, and inhibition of these proteins blocked acid stimulation of NaDC-1 activity.Conclusions Acid stimulation of NaDC-1 activity involves Pyk2/c-Src and Raf1-ERK1/2-p90RSK signaling pathways, but these pathways are not downstream of ET-1/ETB in this process.

A Serine Protease Activity Is Induced by G-CSF and Degrades Stat5 Proteins in Myeloid Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2180-2180
Author(s):  
Yaling Qiu ◽  
Dazhong Zhuang ◽  
Alexandra MacRae ◽  
Fan Dong
Keyword(s):  
Signaling Pathways ◽  
Protease Activity ◽  
Myeloid Cells ◽  
Granulocytic Differentiation ◽  
Protein Levels ◽  
Serine Protease Activity ◽  
Cell Type Specific ◽  
Multiple Signaling ◽  
Activation Status

Abstract Granulocytic progenitor cells become progressively less capable of proliferation and survival with terminal differentiation. Granulocyte colony-stimulating factor (G-CSF) is the major regulator of granulopoiesis and stimulates the activation of multiple signaling pathways including the signal transducer and activator of transcription 5 (Stat5) pathway. Little is known about the activation status of G-CSF-stimulated signaling pathways at the distinct stages of granulocytic differentiation. When myeloid 32D cells transfected with the G-CSF receptor were induced to differentiate with G-CSF, Stat5 activation in response to G-CSF was gradually attenuated. Activation of other signaling molecules including Stat1, Stat3, Erk1/2, JNK and p38 was not altered significantly. Stat5 activation was also downregulated in multipotent FDCP-mix cells, which differentiated into mature granulocytes upon induction with G-CSF, but not in pro-B BaF/3 transfected with the G-CSF receptor, which showed no terminal granulocytic differentiation in response to G-CSF, suggesting that the effect of G-CSF is cell type specific. Attenuated activation of Stat5 correlated with reduced Stat5 protein levels, which was associated with expression of a protease activity capable of degrading Stat5 protein in vitro. The Stat5 protease activity was upregulated when myeloid cells were induced to differentiate with G-CSF, but its upregulation by G-CSF was blocked upon expression of leukemogenic proteins Bcr-Abl and Tel-Jak2. The activity of the Stat5 protease was inhibited partially by PMSF and completely by a1-antitrypsin, suggesting that it belongs to the serine family of protease. Our data provide the first evidence that a Stat5 protease activity is upregulated by G-CSF and may have important implications for understanding the molecular mechanism by which G-CSF orchestrates granulopoiesis.

scholarly journals Multiple Signaling Pathways Are Involved in the Interleukine-4 Regulated Expression of DC-SIGN in THP-1 Cell Line

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Changzhong Jin ◽  
Lijuan Wu ◽  
Jie Li ◽  
Meixin Fang ◽  
Linfang Cheng ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Binding Site ◽  
Signaling Pathways ◽  
Specific Inhibitor ◽  
High Expression ◽  
Intercellular Adhesion Molecule ◽  
Erk Pathway ◽  
Regulated Expression ◽  
Multiple Signaling

Dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN) is an important pattern recognition receptor on dendritic cells (DCs), and its expression shows significant cytological and histological specificity, being interleukine-4 (IL-4) dependent. The signaling pathways through which IL-4 regulates expression of DC-SIGN are still unclear. We used phorbol 12-myristate 13-acetate- (PMA-) differentiated THP-1 cells as thein vitromodel of monocyte/macrophage cells to study the signaling pathways involved in IL-4-regulated expression of DC-SIGN. We found that a high expression of DC-SIGN could be induced by IL-4 at the levels of mRNA and cell surface protein. Upregulated expression of DC-SIGN was almost completely blocked by the specific inhibitor of ERK pathway, and partly reduced by the specific inhibitors of JAK-STAT and NF-κB pathways. The activation of the three signaling pathways was directly confirmed by testing the phosphorylation of protein kinase within the cytoplasm and nucleus over time. The analysis ofcis-acting elements of DC-SIGN promoter showed that the activity of DC-SIGN promoter without Ets-1 transcription factors binding site almost completely disappeared. Our results demonstrated that multiple signaling pathways are involved in IL-4 induced high expression of DC-SIGN on THP-1 cells, in which ERK pathway is the main signaling pathway and mediated by the Ets-1 transcription factors binding site.

Additive Interaction between Oxaliplatin and DMAG in Pediatric Acute Lymphoblastic Leukemia (ALL) Cells. Evidence for Interference with Multiple Signaling Pathways.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4590-4590
Author(s):  
Aarthy Jayanthan ◽  
Jane Fowler ◽  
Lucas Coppes ◽  
Tanya Trippett ◽  
Ron Anderson ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Cell Line ◽  
Cell Lines ◽  
Leukemic Cell ◽  
Signaling Molecules ◽  
Molecular Abnormalities ◽  
Pediatric All ◽  
Multiple Signaling ◽  
Isobologram Analysis

Abstract Oxaliplatin is an analogue from diaminocyclohexanae platinum family of agents that has been found to have significant antitumour activity against a number of aggressive malignancies. However, its effectiveness in the treatment of leukemia has not been widely explored. Studies conducted in a number of solid tumour models indicate that the activity of oxaliplatin is significantly increased when combined with other antineoplastic agents. This provides a unique approach to develop combined treatment protocols with minimum toxicity. We tested the hypothesis that oxaliplatin induced cytotoxicity may be facilitated by a decrease in specific pro-survival signals found in leukemic cells. We took advantage of the observation that ansamycin antibiotics such as 17- (dimethylaminoethylamino) -17-demethoxygeldanamycin (DMAG) affect many of the critical survival pathways by virtue of their ability to induce degradation of critical signaling molecules that are also Hsp-90 client proteins. Cell lines were established from pediatric ALL patients with a spectrum of molecular abnormalities including Bcr-Abl fusion gene (n=8). The ability of oxaliplatin and DMAG to induce apoptosis in these cells was analyzed by cell growth assays using Alamar blue. Western blot analysis was used to detect changes in apoptosis related proteins Bax, BCL-2, p53 and survivin. Preliminary experiments with each agent were used to establish the inhibitory concentrations in culture. The effects of combining oxaliplatin and DMAG were analyzed by isobologram analysis for each cell line. Changes in signaling pathways were identified by an antibody array technique in which changes in phosphorylation and expression of approximately 50 signaling molecules in cells treated with oxaliplatin and DMAG. Results indicate that both agents were able induce apoptosis in all leukemic cell lines. However, IC50 for both agents varied between cell lines and appears to be marginally higher for DMAG compared to oxaliplatin (0.001 to 5 uM/L vs. 0.01 to 10 uM/L). Oxaliplatin had no significant inhibitory effect on one of the cell lines examined. This line was derived from a patient who was originally diagnosed with JMML who then recurred with ALL. The leukemic cell line from Ph chromosome positive ALL showed the highest IC50 for both agents. Isobologram analysis of the data from experiments where both agents were used together suggested an additive effect on most of the lines with some notable exceptions. Antibody arrays showed significant variations in the loss or dephosphorylation of signaling molecules in the presence of oxaliplatin or oxaliplatin and DMAG, most notable Akt1/2, B-catenin and p38 MAPK. We describe strong in vitro data to suggest the potential use of oxaloplatin in combination with DMAG for the treatment of pediatric leukemias. Our methodology also provides an experimental model to conduct in vitro biological correlative studies to monitor the effectiveness of these agents. Finally we provide evidence for the existence of multiple signaling pathways in pediatric ALL cells that are differentially affected by different anti-neoplastic agents and discuss, in detail, the utility of this approach to understand the biology of leukemic growth and survival.

scholarly journals Stimulation of NFκB Activity by Multiple Signaling Pathways Requires PAK1

2000 ◽  
Vol 275 (26) ◽  
pp. 19693-19699 ◽  
Author(s):  
Jeffrey A. Frost ◽  
Jennifer L. Swantek ◽  
Steven Stippec ◽  
Min Jean Yin ◽  
Richard Gaynor ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Multiple Signaling ◽  
Stimulation Of

scholarly journals Multiple Grb2-Mediated Integrin-Stimulated Signaling Pathways to ERK2/Mitogen-Activated Protein Kinase: Summation of Both c-Src- and Focal Adhesion Kinase-Initiated Tyrosine Phosphorylation Events

1998 ◽  
Vol 18 (5) ◽  
pp. 2571-2585 ◽  
Author(s):  
David D. Schlaepfer ◽  
K. C. Jones ◽  
Tony Hunter
Keyword(s):  
Protein Kinase ◽  
Focal Adhesion Kinase ◽  
Signaling Pathways ◽  
Focal Adhesion ◽  
Herbimycin A ◽  
Mitogen Activated Protein ◽  
Erk2 Activation ◽  
Stimulation Of

ABSTRACT Fibronectin receptor integrin-mediated cell adhesion triggers intracellular signaling events such as the activation of the Ras/mitogen-activated protein (MAP) kinase cascade. In this study, we show that the nonreceptor protein-tyrosine kinases (PTKs) c-Src and focal adhesion kinase (FAK) can be independently activated after fibronectin (FN) stimulation and that their combined activity promotes signaling to extracellular signal-regulated kinase 2 (ERK2)/MAP kinase through multiple pathways upstream of Ras. FN stimulation of NIH 3T3 fibroblasts promotes c-Src and FAK association in the Triton-insoluble cell fraction, and the time course of FN-stimulated ERK2 activation paralleled that of Grb2 binding to FAK at Tyr-925 and Grb2 binding to Shc. Cytochalasin D treatment of fibroblasts inhibited FN-induced FAK in vitro kinase activity and signaling to ERK2, but it only partially inhibited c-Src activation. Treatment of fibroblasts with protein kinase C inhibitors or with the PTK inhibitor herbimycin A or PP1 resulted in reduced Src PTK activity, no Grb2 binding to FAK, and lowered levels of ERK2 activation. FN-stimulated FAK PTK activity was not significantly affected by herbimycin A treatment and, under these conditions, FAK autophosphorylation promoted Shc binding to FAK. In vitro, FAK directly phosphorylated Shc Tyr-317 to promote Grb2 binding, and in vivo Grb2 binding to Shc was observed in herbimycin A-treated fibroblasts after FN stimulation. Interestingly, c-Src in vitro phosphorylation of Shc promoted Grb2 binding to both wild-type and Phe-317 Shc. In vivo, Phe-317 Shc was tyrosine phosphorylated after FN stimulation of human 293T cells and its expression did not inhibit signaling to ERK2. Surprisingly, expression of Phe-925 FAK with Phe-317 Shc also did not block signaling to ERK2, whereas FN-stimulated signaling to ERK2 was inhibited by coexpression of an SH3 domain-inactivated mutant of Grb2. Our studies show that FN receptor integrin signaling upstream of Ras and ERK2 does not follow a linear pathway but that, instead, multiple Grb2-mediated interactions with Shc, FAK, and perhaps other yet-to-be-determined phosphorylated targets represent parallel signaling pathways that cooperate to promote maximal ERK2 activation.

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