scholarly journals Adiponectin as Well as Compressive Forces Regulate in vitro β-Catenin Expression on Cementoblasts via Mitogen-Activated Protein Kinase Signaling Activation

Author(s):  
Jiawen Yong ◽  
Julia von Bremen ◽  
Gisela Ruiz-Heiland ◽  
Sabine Ruf

We aimed to investigate the molecular effect that adiponectin exerts on cementoblasts especially in the presence of compressive forces. OCCM-30 cells (M. Somerman, NIH, NIDCR, United States) were used. Real-time reverse transcriptase–polymerase chain reaction (RT-PCR) and western blots were employed to verify if the mRNA and protein levels of adiponectin receptors (AdipoRs), mitogen-activated protein kinase (MAPK), and β-catenin signaling were influenced by compressive forces or adiponectin. Moreover, siRNAs targeting P38α, JNK1, ERK1, ERK2, and AdipoRs as well as pharmacological MAPK inhibition were performed. We found that compressive forces increase the expression of AdipoRs. Adiponectin and compression up-regulate P38α,JNK1, ERK1, and ERK2 as well as β-catenin gene expression. Western blots showed that co-stimuli activate the MAPK and β-catenin signaling pathways. MAPK inhibition alters the compression-induced β-catenin activation and the siRNAs targeting AdipoRs, P38α, and JNK1, showing the interaction of single MAPK molecules and β-catenin signaling in response to compression or adiponectin. Silencing by a dominantly negative version of P38α and JNK1 attenuates adiponectin-induced TCF/LEF reporter activation. Together, we found that light compressive forces activate β-catenin and MAPK signaling pathways. Adiponectin regulates β-catenin signaling principally by inactivating the GSK-3β kinase activity. β-Catenin expression was partially inhibited by MAPK blockade, indicating that MAPK plays a crucial role regulating β-catenin during cementogenesis. Moreover, adiponectin modulates GSK-3β and β-catenin mostly through AdipoR1. P38α is a key connector between β-catenin, TCF/LEF transcription, and MAPK signaling pathway.

Author(s):  
Tiziana Latronico ◽  
Marilena Larocca ◽  
Serafina Milella ◽  
Anna Fasano ◽  
Rocco Rossano ◽  
...  

AbstractIsothiocyanates (ITCs), present as glucosinolate precursors in cruciferous vegetables, have shown anti-inflammatory, antioxidant and anticarcinogenic activities. Here, we compared the effects of three different ITCs on ROS production and on the expression of matrix metalloproteinase (MMP)-2 and -9, which represent important pathogenetic factors of various neurological diseases. Primary cultures of rat astrocytes were activated by LPS and simultaneously treated with different doses of Allyl isothiocyanate (AITC), 2-Phenethyl isothiocyanate (PEITC) and 2-Sulforaphane (SFN). Results showed that SFN and PEITC were able to counteract ROS production induced by H2O2. The zymographic analysis of cell culture supernatants evidenced that PEITC and SFN were the most effective inhibitors of MMP-9, whereas, only SFN significantly inhibited MMP-2 activity. PCR analysis showed that all the ITCs used significantly inhibited both MMP-2 and MMP-9 expression. The investigation on the mitogen-activated protein kinase (MAPK) signaling pathway demonstrated that ITCs modulate MMP transcription by inhibition of extracellular-regulated protein kinase (ERK) activity. Results of this study suggest that ITCs could be promising nutraceutical agents for the prevention and complementary treatment of neurological diseases associated with MMP involvement.


2002 ◽  
Vol 22 (6) ◽  
pp. 631-647 ◽  
Author(s):  
Elaine A. Irving ◽  
Mark Bamford

Protein kinase-mediated signaling cascades constitute the major route by which cells respond to their extracellular environment. Of these, three well-characterized mitogen-activated protein kinase (MAPK) signaling pathways are those that use the extracellular signal-regulated kinase (ERK1/2) or the stress-activated protein kinase (p38/SAPK2 or JNK/SAPK) pathways. Mitogenic stimulation of the MAPK-ERK1/2 pathway modulates the activity of many transcription factors, leading to biological responses such as proliferation and differentiation. In contrast, the p38/SAPK2 and JNK/SAPK (c-Jun amino-terminal kinase/stress-activated protein kinase) pathways are only weakly, if at all, activated by mitogens, but are strongly activated by stress stimuli. There is now a growing body of evidence showing that these kinase signaling pathways become activated following a variety of injury stimuli including focal cerebral ischemia. Whether their activation, however, is merely an epiphenomenon of the process of cell death, or is actually involved in the mechanisms underlying ischemia-induced degeneration, remains to be fully understood. This review provides an overview of the current understanding of kinase pathway activation following cerebral ischemia and discusses the evidence supporting a role for these kinases in the mechanisms underlying ischemia-induced cell death.


Reproduction ◽  
2004 ◽  
Vol 128 (5) ◽  
pp. 517-526 ◽  
Author(s):  
Anne Navarrete Santos ◽  
Sarah Tonack ◽  
Michaela Kirstein ◽  
Marie Pantaleon ◽  
Peter Kaye ◽  
...  

The addition of insulin during in vitro culture has beneficial effects on rabbit preimplantation embryos leading to increased cell proliferation and reduced apoptosis. We have previously described the expression of the insulin receptor (IR) and the insulin-responsive glucose transporters (GLUT) 4 and 8 in rabbit preimplantation embryos. However, the effects of insulin on IR signaling and glucose metabolism have not been investigated in rabbit embryos. In the present study, the effects of 170 nM insulin on IR, GLUT4 and GLUT8 mRNA levels, Akt and Erk phosphorylation, GLUT4 translocation and methyl glucose transport were studied in cultured day 3 to day 6 rabbit embryos. Insulin stimulated phosphorylation of the mitogen-activated protein kinase (MAPK) Erk1/2 and levels of IR and GLUT4 mRNA, but not phosphorylation of the phosphatidylinositol 3-kinase-dependent protein kinase, Akt, GLUT8 mRNA levels, glucose uptake or GLUT4 translocation. Activation of the MAPK signaling pathway in the absence of GLUT4 translocation and of a glucose transport response suggest that in the rabbit preimplantation embryo insulin is acting as a growth factor rather than a component of glucose homeostatic control.


2005 ◽  
Vol 22 (1) ◽  
pp. 57-69 ◽  
Author(s):  
C. N. Hahn ◽  
Z. J. Su ◽  
C. J. Drogemuller ◽  
A. Tsykin ◽  
S. R. Waterman ◽  
...  

Angiogenesis is a complex multicellular process requiring the orchestration of many events including migration, alignment, proliferation, lumen formation, remodeling, and maturation. Such complexity indicates that not only individual genes but also entire signaling pathways will be crucial in angiogenesis. To define an angiogenic blueprint of regulated genes, we utilized our well-characterized three-dimensional collagen gel model of in vitro angiogenesis, in which the majority of cells synchronously progress through defined morphological stages culminating in the formation of capillary tubes. We developed a comprehensive three-tiered approach using microarray analysis, which allowed us to identify genes known to be involved in angiogenesis and genes hitherto unlinked to angiogenesis as well as novel genes and has proven especially useful for genes where the magnitude of change is small. Of interest is the ability to recognize complete signaling pathways that are regulated and genes clustering into ontological groups implicating the functional importance of particular processes. We have shown that consecutive members of the mitogen-activated protein kinase and leukemia inhibitory factor signaling pathways are altered at the mRNA level during in vitro angiogenesis. Thus, at least for the mitogen-activated protein kinase pathway, mRNA changes as well as the phosphorylation changes of these gene products may be important in the control of blood vessel morphogenesis. Furthermore, in this study, we demonstrated the power of virtual Northern blot analysis, as an alternative to quantitative RT-PCR, for measuring the magnitudes of differential gene expression.


2006 ◽  
Vol 11 (4) ◽  
pp. 423-434 ◽  
Author(s):  
Charlotta Grånäs ◽  
Betina Kerstin Lundholt ◽  
Frosty Loechel ◽  
Hans-Christian Pedersen ◽  
Sara Petersen Bjørn ◽  
...  

The RAS-mitogen-activated protein kinase (MAPK) signaling pathway has a central role in regulating the proliferation and survival of both normal and tumor cells. This pathway has been 1 focus area for the development of anticancer drugs, resulting in several compounds, primarily kinase inhibitors, in clinical testing. The authors have undertaken a cell-based, high-throughput screen using a novel ERF1 Redistribution® assay to identify compounds that modulate the signaling pathway. The hit compounds were subsequently tested for activity in a functional cell proliferation assay designed to selectively detect compounds inhibiting the proliferation of MAPK pathway-dependent cancer cells. The authors report the identification of 2 cell membrane-permeable compounds that exhibit activity in the ERF1 Redistribution® assay and selectively inhibit proliferation of MAPK pathway-dependent malignant melanoma cells at similar potencies (IC50 =< 5 μM). These compounds have drug-like structures and are negative in RAF, MEK, and ERK in vitro kinase assays. Drugs belonging to these compound classes may prove useful for treating cancers caused by excessive MAPK pathway signaling. The results also show that cell-based, high-content Redistribution® screens can detect compounds with different modes of action and reveal novel targets in a pathway known to be disease relevant.


2003 ◽  
Vol 2 (6) ◽  
pp. 1187-1199 ◽  
Author(s):  
Philip Müller ◽  
Gerhard Weinzierl ◽  
Andreas Brachmann ◽  
Michael Feldbrügge ◽  
Regine Kahmann

ABSTRACT In the phytopathogenic fungus Ustilago maydis, pheromone-mediated cell fusion is a prerequisite for the generation of the infectious dikaryon. The pheromone signal elevates transcription of the pheromone genes and elicits formation of conjugation hyphae. Cyclic AMP and mitogen-activated protein kinase (MAPK) signaling are involved in this process. The MAPK cascade is presumed to be composed of Ubc4 (MAPK kinase kinase), Fuz7 (MAPK kinase), and Ubc3/Kpp2 (MAPK). We isolated the kpp4 gene and found it to be allelic to ubc4. Epistasis analyses with constitutively active alleles of kpp4 and fuz7 substantiate that Kpp4, Fuz7, and Kpp2/Ubc3 are components of the same module. Moreover, we demonstrate that Fuz7 activates Kpp2 and shows interactions in vitro. Signaling via this cascade regulates expression of pheromone-responsive genes, presumably through acting on the transcription factor Prf1. Interestingly, the same cascade is needed for conjugation tube formation, and this process does not involve Prf1. In addition, fuz7 as well as kpp4 deletion strains are nonpathogenic, while kpp2 deletion mutants are only attenuated in pathogenesis. Here we show that strains expressing the unphosphorylatable allele kpp2T182A/Y184F are severely affected in tumor induction and display defects in early infection-related differentiation.


Author(s):  
Hua Luo ◽  
Chi Teng Vong ◽  
Dechao Tan ◽  
Jinming Zhang ◽  
Hua Yu ◽  
...  

Panax notoginseng saponins (PNS) are the main active ingredients of Panax notoginseng (Burk) F. H. Chen, which are used as traditional Chinese medicine for thousands of years and have various clinical effects, including anti-inflammation, anti-oxidation, and cardiovascular protection. Inflammatory bowel disease (IBD) is a complex gastrointestinal inflammatory disease that cannot be cured completely nowadays. The anti-inflammatory and protective effects of PNS were analyzed in vitro and in dextran sulfate sodium (DSS)-induced colitis mouse model. PNS inhibited the release of nitric oxide (NO), tumor necrosis factor-[Formula: see text] (TNF-[Formula: see text], interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1) in Pam3CSK4-induced RAW 264.7 macrophages. In the animal study, compared with DSS-induced mice, PNS reduced the expression of pro-inflammatory cytokines (TNF-[Formula: see text], IL-6, and MCP-1) in the colon tissues. Furthermore, PNS treatment led to a remarkable reduction in the activation of the inhibitor of nuclear factor kappa-B kinase [Formula: see text]/[Formula: see text] (IKK[Formula: see text]/[Formula: see text], I[Formula: see text]B[Formula: see text] and p65 induced by DSS. On the other hand, PNS inhibited the phosphorylation of c-Jun N-terminal kinase (JNK), p38, and extracellular regulated protein kinase 1/2 (ERK1/2). Taken together, our results suggested that PNS conferred profound protection for colitis mice through the downregulation of mitogen-activated protein kinase (MAPK) and NF-[Formula: see text]B signaling pathways, which were associated with reducing inflammatory responses, alleviating tissue damage, and maintaining of intestinal integrity and functionality.


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